Title of Invention

TRANSMISSION FOR WORK VEHICLE

Abstract A transmission for work vehicle comprises' a transmission case; a first transmission shaft for input of power from an engine of the work vehicle, a wide gear supported to the first transmission shaft to be rotatable therewith; a second transmission shaft provided within the transmission case and extending parallel to the first transmission shaft; a first transmission gear supported to the second transmission shaft in one side region thereof to be rotatable therewith, the first transmission gear being in constant engagement with the wide gear; a large diameter gear supported to the second transmission shaft in other side region thereof to be rotatable therewith; a third transmission shaft for output, the third transmission shaft being provided within the transmission case and extending parallel to the first transmission shaft, and a first shift gear supported to the third transmission shaft in one side region thereof to be rotatable therewith, the first shift gear being shiffcable relative to the third transmission shaft between an engaging position and a disengaging position with the wide gear; a second shift gear supported to the third transmission shaft in other side region thereof to be rotatable therewith, the second shift gear being shiftable relative to the third transmission shaft between an engaging position and a disengaging position with the large diameter gear. This invention relates to a transmission for work vehicle such as a tractor.
Full Text FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE
TRANSMISSION FOR WORK VEHICLE
APPLICANT
KUBOTA CORPORATION
of 2-47, Shikitsuhigashi 1-chome, Naniwa-ku, Osaka-shi,
Osaka, Japan; Nationality: a Japanese corporation
and
THE SIAM KUBOTA INDUSTRY CO., LTD.
of 101/19-24, Moo20, Navanakorn, Khlongneung Khlongluang,
Pathumtani 12120, Thailand; Nationality: a Thai company
The following specification particularly describes
the nature of this invention and the manner in which it is to be performed

BACKGROUND OF THE INVENTION
Transmission for a work vehicle is constructed such that with realization of a traveling transmission condition, one of a plurality of gears incorporated in a traveling transmission line is stopped (see e.g. Japanese Published Utility Model No. 2-44131).
With the above-described construction, in feeding transmission oil to
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respect portions in a transmission case with e.g. splashing-up of the transmission oil by gears, the efficiency of feeding the oil to the respective portions may be reduced. And, if the amount of oil inside the transmission case is small, the feeding of the oil to the respective portions may become reliable, thus presenting the risk of seizure of the bearings or the like.
SUMMARY OF THE INVENTION
The object of the present invention is to reliably avoid such seizure of bearings or the like inside the transmission case.
A transmission for work vehicle comprises- a transmission case; a first transmission shaft for input of power from an engine of the work vehicle, a wide gear supported to the first transmission shaft to be rotatable therewith; a second transmission shaft provided within the transmission case and extending parallel to the first transmission shaft; a first transmission gear supported to the second transmission shaft in one side region thereof to be rotatable therewith, the first transmission gear being in constant engagement with the wide gear; a large diameter gear supported to the second transmission shaft in other side region thereof to be rotatable therewith; a third transmission shaft for output, the third transmission shaft being provided within the transmission case and extending parallel to the first transmission shaft, and a first shift gear supported to the third transmission shaft in one side region thereof to be rotatable therewith, the first shift gear being shiftable relative to the third transmission shaft between an engaging position and a disengaging position with the wide gear; a second shift gear supported to the third transmission shaft in other side region thereof to be rotatable therewith, the second shift gear being shiftable relative to the third transmission shaft between an engaging position and a disengaging position with the large diameter gear.
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With this construction, under either the condition when the first shift gear is meshed with the wide gear or the condition when the second shift gear is meshed with the large gear, all the gears are rotated. Hence, the splashing feeding of the transmission oil to the respective portions inside the transmission case by the splashing-up of the oil by the gears can be effected in a stable manner over an extended area.
Therefore, in addition to more reliable avoidance of the seizure of the bearings or the like inside the transmission case, power transmission with a large speed changing ratio can be effected.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an overall left side view of a tractor,
Fig. 2 is an overall right side view of the tractor,
Fig. 3 is an overall plan view of the tractor,
Fig. 4 is an overall perspective view of the tractor as seen from its right front side,
Fig. 5 an overall perspective view of the tractor as seen from its left rear side,
Fig. 6 is a schematic overall left side view of the tractor,
Fig. 7 is a perspective view of principal portions showing arrangements of an engine, a transmission case, etc.,
Fig. 8 is a rear view in vertical section of the transmission case,
Fig. 9 is a rear view in vertical section of principal portions of the transmission case,
Fig. 10 is a side view in vertical section of the transmission case,
Fig. 11 is a rear view in vertical section of principal portions of the transmission case allowing power takeoff,
Fig. 12 is a side view in vertical section of principal portions of the transmission case allowing power takeoff,
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Fig. 13 is an exploded plan view in section of the principal portions of the transmission case,
Fig. 14 is a perspective view of principal portions showing a speed changing operational construction,
Fig. 15 is a left side view of principal portions showing the speed changing operational construction,
Fig. 16 is a plan view of the principal portions showing the speed changing operational construction,
Fig. 17 is a front view in vertical section of principal portions showing a main speed changing operational construction,
Fig. 18 is a front view in vertical section of principal portions showing an auxiliary speed changing operational construction,
Fig. 19 is a plan view in section of principal portions showing the auxiliary speed changing operational construction,
Fig. 20 is a rear view in vertical section of principal portions showing a sealing construction,
Fig. 21 is a rear view in vertical section of principal portions showing a supporting construction for an auxiliary transmission line in the transmission case,
Fig. 22 is a rear view in vertical section of principal portions showing an exploded condition of the transmission case,
Fig. 23 is a side view in vertical section of a rear portion of the transmission case,
Fig. 24 is a perspective view of principal portions showing arrangement of a working oil tank and its supporting construction,
Fig. 25 is a perspective view of principal portions showing a maintenance construction for an air cleaner,
Fig. 26 is a perspective view of principal portions showing an accelerator operational construction as seen from the right rear side thereof,
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Fig. 27 is a perspective view of principal portions showing the accelerator operational construction as seen from the left rear side thereof,
Fig. 28 is a side view of principal portions showing the accelerator operational construction,
Fig. 29 is a side view in vertical section of principal portions showing the accelerator operational construction,
Fig. 30 is an exploded perspective view of principal portions showing the accelerator operational construction,
Fig. 31 is a plan view in section of principal portions showing the accelerator operational construction,
Fig. 32 is a perspective view of principal portions showing arrangement and supporting construction for a lift cylinder and a lift arm.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Fig. 1 is an overall left side view of a tractor as an example of a work vehicle. Fig. 2 is an overall right side view of the tractor. Fig. 3 is an overall plan view of the tractor. Fig. 4 is an overall perspective view of the tractor as seen from its right front side. Fig. 5 is an overall perspective view of the tractor as seen from its left rear side. Fig. 6 is a schematic overall left side view of the tractor. This tractor includes a vehicle body frame 1 provided in the form of a framework made of band steel or the like, a riding operator's section 2 formed at a rear portion of the vehicle body frame 1, an engine 3 mounted at a front portion of the vehicle body frame 1, a transmission case 4 connected to a rear end of the vehicle body frame 1 and acting also as a frame, front wheels 5 disposed at the front right and left sides of the vehicle body frame 1, rear wheels 6 disposed on the right and left sides of the transmission case 4, a hydraulic lift cylinder 7 disposed upwardly of the transmission case 4, a pair of right and left Kft arms 8 pivotable up/down with an operation of the lift cylinder 7, and so on. At a rear portion of the
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tractor 7, an implement such as an unillustrated disc plow, a rotary plow , etc. or a trailer, can be operatively connected via e.g. a link mechanism 9.
The riding operator’s section 2 includes a boarding step 10 provided on the rear side of the vehicle body frame 1, a steering wheel 11 for steering the right and left front wheels 5, a driver's seat 12 disposed rearwardly of and with a predetermined space relative to the steering wheel 11, and so on.
As shown in Figs. 1-9, the engine 3 is a lateral mount type diesel engine mounted such that its output shaft 13 extends to the left side of the vehicle body and the engine is mounted at the front portion of the vehicle body frame 1, with the entire engine being dispose at a position higher than the boarding step 10. Power from this engine 3 is transmitted, via a belt transmission device 14 and a dry multiple plate type main clutch 15, to a first input transmission shaft 16 disposed at a front end upper portion of the transmission case 4.
As shown in Figs. 1-5 and Figs. 8-11, the transmission case 4 incorporates therein a traveling transmission line 27 including the following components for example. Namely, in association with an operation of a main speed change lever (an example of “manually operated member”) 17 disposed on the left side of the driver's seat 12 at the riding operator's section 2, a gear type main speed change device 18 switches over the power transmitted to the first transmission shaft 16, among a neutral condition where the power is not transmitted to the transmission downstream side, a reverse traveling condition where the power is transmitted as being speed-changed into a low speed reverse power for reverse traveling, a low speed forward traveling condition suitable for e.g. a rotary plow operation, where the power is transmitted as being speed-changed into a low speed forward rotational force, an intermediate speed forward traveling condition suitable for e.g. a disc plow operation, where the power is transmitted as being speed-changed into an intermediate speed forward rotational force, and a high speed forward
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traveling condition suitable for e.g. a trailer operation, where the power is transmitted as being speed-changed into a high speed forward rotational force. In association with an operation of an auxiliary speed change lever (another example of “operational tool”) 19 disposed rearwardly of the main speed change lever 17, a gear type auxiliary speed change device 20 switches over the speed-changed power from the main speed change device 18, among a neutral condition where the power is not transmitted to the transmission downstream side, a low speed condition where the power is transmitted as being speed-changed into a low speed power, and a high speed condition where the power is transmitted as being speed-changed into a high speed power. A rear wheel differential device 22 transmits the speed-changed power from the auxiliary speed change device 20 to a pair of right and left differential shafts (an example of “transmission shaft”) 21 with allowing differential rotation there between. In association with a step-on operation on a differential lock pedal 23 disposed at the right lower side of the driver's seat 12 at the riding operator's section 2, a lock mechanism 24 switches over a released condition where the differential movement of the right and left differential shafts 21 by the rear wheel differential device 22 is allowed, to a locked condition where the differential movement is inhibited. A transmission gear 26 transmits the power from the right and left differential shafts 21 to rear axles (still another example of “transmission shaft”) 25.
As shown in Figs. 6-12, the transmission case 4 can be divided into four portions along the right/left direction of the vehicle body. A first case portion 28 having a large capacity and a second case portion 29 having a small capacity, which are disposed at the right and left center of the case, together support, at the front end upper portion thereof, the first transmission shaft 16 oriented along the right/left direction, with a left end of the shaft projecting to the left side from the first case portion 28. Within an accommodating space formed between the first case portion 28 and the
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second case portion 29, there are accommodated the main speed change device 18, the auxiliary speed change device 20 and the rear wheel differential device 22. Within an accommodating space formed between the first case portion 28 and a third case portion 30 disposed on the left side thereof, there are accommodated the lock mechanism 24, the left differential shaft 21 and the transmission gear 26. The first case portion 28 and the third case portion 30 together support the left rear axle 25, with the shaft extending to the left side from the third case portion 30. Within an accommodating space formed between the second case portion 29 and a fourth case portion 31 disposed on the right side thereof, there are accommodated the right differential shaft 21 and the transmission gear 26. The second case portion 29 and the fourth case portion 31 together support the right rear axle 25, with the shaft extending to the right side from the fourth case portion 31. Further, an output section 32 having the right and left rear axles 25 and the transmission gear 26 is disposed at the rearmost and lowermost portion of the case. An upper half portion including e.g. the first transmission shaft 16 is disposed under a forward rising posture, with a front end portion thereof including the first transmission shaft 16 being located upward and is disposed at a position higher than the boarding step 10.
And, the bottom side of the fourth case portion 31 together with the bottom side of the second case portion 29 formed narrow are bolt-connected to the bottom side of the first case portion 28. With this, compared with a conceivable construction in which e.g. the bottom side of the first case portion 28 is provided, at vertical portions thereof, with a connecting area dedicated for the bolt-connection with the bottom side of the fourth case portion 31 and a further connecting area dedicated for the further bolt-connection with the bottom side of the second case portion 29, the above-described construction allows restriction in the amount of bulging of the bottom side of the
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transmission case 4, thus providing a greater ground-clearance for the transmission case 4.
As shown in Figs. 8- 19, at an upper area of the transmission case 4, there are provided a first operational shaft 35 for slidably operating a first shift gear 33 of the main speed change device 18 via a first shift fork (an example of a “movable member”) 34, to and from reverse traveling positions Rl, R2 and low speed forward traveling positions Fl, F2, a second operational shaft 38 for slidably operating a second shift gear 36 of the main speed change device 18 via a second shift fork (another example of “movable member”) 37 to and from intermediate speed forward traveling positions F3, F4 and high speed forward traveling positions F5, F6 and a third operational shaft 41 for slidably operating a shift gear 39 of the auxiliary speed change device 20 via a third shift fork (still another example of “movable member”) 40 to and from a low speed position L and a high speed position H, and a fourth operational shaft 44 for slidably operating a shift pawl 42 of the lock mechanism 24 via a fourth shift fork 43 to and from a locked position and a released position.
The first operational shaft 35 is operatively coupled to the main speed change lever 17 via a first coupling mechanism LI and the second operational shaft 38 is operatively coupled also with the main speed change lever 17, via a second coupling mechanism L2, respectively, with each shaft 35, 38 being selectively coupled with an operation of the main speed change lever 17. With this operable coupling, when the main speed change lever 17 is operated along a main speed changing guide groove 45A formed in an "H"-shape in a lever guide 45 to one of the neutral position N, reverse traveling positions Rl, R2, low speed forward traveling positions Fl, F2, intermediate speed forward traveling positions F3, F4 and the high speed forward traveling positions F5, F6, in correspondence with such operated position, the main speed change 18 is switched over to the neutral condition, reverse traveling condition,
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intermediate speed forward traveling condition, or the high speed forward traveling condition.
The third operational shaft 41 is operatively coupled with the auxiliary speed change lever 19 via a third coupling mechanism L3. With this operable coupling, when the auxiliary speed change lever 19 is operated along an auxiliary speed changing guide groove 45B formed in a straight line shape in the lever guide 45 to the neutral position N, low speed position L or the high speed position H, in correspondence with such operated position, the auxiliary speed change device 20 is switched over to the neutral condition, the low speed condition or the high speed condition.
The fourth operational shaft 44 is operatively coupled with the differential lock pedal 23 via a fourth coupling mechanism (not shown). With this operable coupling, when the differential lock pedal 23 is stepped on, the lock mechanism 24 is switched over from the released condition to the locked condition. Upon release of the stepping-on operation of the differential lock pedal 23, the lock mechanism 24 is switched over from the locked condition to the released condition.
Incidentally, the speed at the forward traveling first position Fl for realizing the low speed forward traveling condition for the rotary plow for effecting a rotary plow operation is set to about 1.1 kg/h. The speed at the forward traveling second speed position F2 for realizing the high-speed forward traveling condition for a rotary plow operation is set to about 1.7 kg/h. The speed at the forward traveling third speed position F3 for realizing the low speed forward traveling condition for the disc plow for effecting a disc plow operation is set to about 3.8 kg/h. The speed at the forward traveling fourth speed position F4 for realizing the high speed traveling condition for the disc plow operation is set to about 6.0 kg/h. The speed at the forward traveling fifth speed position F5 for realizing the low speed forward traveling condition for the trailer for effecting a trailer
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operation is set to about 13.8 kg/m. The speed at the forward traveling sixth speed position F6 for realizing the high speed traveling condition for the trailer operation is set to about 21.7 kg/h. The speed at the reverse traveling first position Rl for realizing the reverse traveling low speed condition is set to about 2.8 kg/m. The speed at the reverse traveling second position F2 for realizing the reverse traveling high speed condition is set to about 4.3 kg/h, respectively.
As shown in Figs. 2-4, Fig. 8 and Figs. 9 and 11, between the first case portion 28 and the third case portion 30 and between the second case portion 29 and the fourth case portion 31, there is respectively accommodated a wet multiple plate type side brake 47 for applying a braking force corresponding to a step-on operation on a corresponding one of right and left brake pedals 46 arranged at the right forward area of the riding operator's section 2, to the associated differential shaft 21.
As shown in Fig. 8, Fig. 9 and Fig. 11, the third case portion 30 and the fourth case portion 31 each incorporates an operational shaft 48 for braking one side brake 47 associated therewith. Between these operational shafts 48 and bearing portions 30A, 31A of the third case portion 30 and the fourth case portion 31 for supporting these shafts 48, there are interposed oil seals 49 to be attachable and detachable from the outside of the transmission case 4.
As shown in Fig. 13, also between the first operational shaft 35 and the second operational shaft 38 described hereinbefore and bearing portions 28A, 28B of the first case portion 28 supporting these shafts, there are interposed oil seals 49. Further, though not shown, also between the third operational shaft 41 and the fourth operational shaft 44 described hereinbefore and bearing portions of the first case portion 28 supporting these shafts, there are interposed oil seals 49 to be attachable and detachable from the outside of the transmission case 4.
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As shown in Fig. 8 and Fig. 20, between the left rear axle 25 and a bearing portion 30B of the third case portion 30 supporting its outer side and between the right rear axle 25 and a bearing portion 3 IB of the fourth case portion 31 supporting its outer side, there are respectively provided two oil seals 50, 51 side by side,. Of these oil seals 50, 51, the oil seal 51 disposed on the outer side of the vehicle body is adapted to be attachable and detachable from the outside of the transmission case 4.
On outer ends of the bearing portions 31A, 3 IB of the third case portion 30 and the fourth case portion 31 for the rear axles 25, there are attached covers 52 for preventing adhesion or intrusion of muddy water or the like to or between the right and left rear axles 25 and the bearing portions 30B, 3 IB therefor.
As shown in Figs. 7-13, the first case portion 28 is provided with a great depth so as to provide a large accommodating capacity for accommodating substantially entirely the main speed change device 18, the auxiliary speed change device 20 and the rear differential device 22. And, at a rear end of this first case portion 28, there is provided a power takeout portion 28C for allowing mounting of a power takeout (PTO) unit 53.
More particularly, the transmission case 4 is adapted for allowing selection of use modes between a first use mode (see Figs. 8-10) not mounting the PTO unit 53 targeted to a user who desires to effect an operation not requiring any implement power takeoff from the transmission case 4 for a disc plow operation, a trailer operation, etc. and a second use mode (see Fig. 11 and Fig. 12) mounting the PTO unit 53 targeted to a user who desires to effect an operation requiring some implement power takeoff from the transmission case 4 for e.g. a rotary plow operation. In the first use mode, a cover 54 is bolt-connected to the PTO portion 28C for closing a power takeoff opening 28a formed in this PTO portion 28C.
As shown in Fig. 12, referring to the PTO unit 53 which is mounted in
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the second use mode, a substantially cylindrical PTO case 55 bolt-connected to the PTO portion 28C supports, via a first bearing 56 and a pair of oil seals 57, 58, a PTO shaft 59 for allowing power transmission to an implement and at an end of this PTO shaft 59 on the side of the transmission case 4, there are mounted a bevel gear 60 and a second bearing 61.
Of the pair of oil seals 57, 58, the oil seal 58 disposed on the outer side of the vehicle body is attachable and detachable from the outside of the transmission case 4.
As shown in Fig. 8, Fig. 9, Fig. 11, Fig. 13 and Fig. 21, the second case portion 29 is formed shallow like a lid sectioned from the first case portion 28 by a dividing line PL set adjacent enough to provide a first bearing portion 29A for supporting the right end of the first transmission shaft 16, second through fifth bearing portions 29B-29E supporting respective right ends of second through fifth transmission shafts 62-65 disposed parallel with the first transmission shaft 16, a sixth bearing portion 29F for supporting the left end of the right differential shaft 21 and a seventh bearing portion 29G for supporting the left end of the right rear axle 25, the dividing line PL extending normal to the respective shafts 16, 21, 25 and 62-65. At upper forward and rear portions of the second case portion 29, there are provided supporting portions 67 for detachably supporting an auxiliary transmission line 66 for allowing power transmission from the first transmission shaft 16 to the PTO shaft 59 in the second use condition. These support portions 67 can be divided into two portions, i.e. a first supporting portion 68 to be first bolt-connected to the second case portion 29 and a second supporting portion 69 to be subsequently bolt-connected to the second case portion 28 together with the first supporting portion 68 after the connection thereof.
As shown in Fig. 12, the auxiliary transmission line 66 which is mounted in the second use mode is provided as a shaft transmission type including bevel gears 71, 72 mounted on opposed ends of an auxiliary
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transmission shaft 70 disposed upwardly of the second through fifth transmission shafts 62-65 under a posture normal to the first transmission shaft 16 and the second through fifth transmission shafts 62-65, etc. And, this auxiliary transmission shaft 70 is supported via bearings 73 to the forward and rear supporting portions 67. The bevel gear 71 mounted on one end of the shaft is meshed with a bevel gear 74 mounted on the first transmission shaft 16 and the bevel gear 72 mounted on the other end thereof is meshed with a bevel gear 60 of the PTO unit 53.
As shown in Fig. 11 and Fig. 12, in the second use mode, between the first transmission shaft 16 and the bevel gear 74, there is interposed an auxiliary clutch 75 for switching over power transmission condition from the first transmission shaft 16 to the PTO shaft 59. At upper portions of the first case portion 29 and the second case portion 29, there is provided a fifth operational shaft 78 for slidably operating a shift member 76 of the auxiliary clutch 75 via a fifth shift fork 77 to and from a transmitting position and a non-transmitting position. This fifth operational shaft 78 is operatively coupled via an unillustrated coupling mechanism with an auxiliary clutch lever 79 (see Fig. 1, Fig. 2 and Fig. 4) disposed on the right side of the driver's seat 12 at the riding operator's section 2.
Further, though not shown, between the fifth operational shaft 78 and bearing portions of the first case portion 28 and the second case portion 29 supporting the shaft, there are also interposed oil seals 49 to be attachable and detachable from the outside of the transmission case 4.
Namely, each of the oil seals 49, 51, 58 other than the inner side oil seals 50, 57 can be readily replaced by a new one from outside the transmission case 4, without requiring disassemble of the transmission case 4. Further, as the sealing portion disposed lower than a reference level OS of transmission oil is constructed as a double construction, there is no trouble of draining the transmission oil for the replacement of the outer side oil seals
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51, 58. As a result, it is possible to speedily cope with wear or damage in the oil seals 49, 51, 58.
As shown in Figs. 8-13, inside the transmission case 4, on the left end of the first transmission shaft 16, there is mounted a wide gear 80 rotatable in unison with the first transmission shaft 16. And, power outputted from this wide gear 80 is transmitted to the main speed change device 18.
The second transmission shaft 62 disposed adjacent downwardly of the first transmission shaft 16 mounts a small gear 81 for low speed forward traveling, a first transmission gear 82 constantly meshed with the wide gear 80, an intermediate gear 83 for the intermediate speed forward traveling, and a large gear 84 for high speed forward traveling, with these gears being arranged in the mentioned order from the left end of the shaft 62 and spilled with this second transmission shaft 62 to be rotatable in unison therewith. The third transmission shaft 63 disposed adjacent downwardly of the first transmission shaft 16 and the second transmission shaft 62 mounts the first shift gear 33 slidable to the rear traveling positions Rl, R2 meshed with the wide gear 80, the low speed forward traveling positions Fl, F2 meshed with the small gear 81 and the neutral position N meshed with neither of these gears 80, 81, the second shift gear 36 slidable to the intermediate speed forward traveling positions F3, F3 meshed with the intermediate gear 83, the high speed forward traveling positions F5, F6 meshed with the large gear 84 and the neutral position N meshed with neither of thee gears 83, 84 and a second transmission gear 85, with these gears being arranged in the mentioned order from the left end of the shaft 63 and splined with this third transmission shaft 63 to be rotatable in unison therewith. And, the second transmission shaft 62, the third transmission shaft 63 and the respective gears 33, 36, 81-85 mounted on these transmission shafts 62, 63 together constitute the main speed change device 18.
The fourth transmission shaft 64 disposed adjacent downwardly of
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the third transmission shaft 63 mounts the shift gear 39 and a third transmission gear 86 constantly meshed with the second transmission gear 85, with these gears 39, 86 being arranged in the mentioned order from the left end of the shaft and splined with this fourth transmission shaft 64 to be rotatable in unison therewith. The fifth transmission shaft 65 disposed adjacent downwardly of the fourth transmission shaft 64 mounts a large low speed gear 87, a small fourth transmission gear 89 constantly meshed with the input gear 88 of the rear wheel differential device 22 and an intermediate-sized high speed gear 90, with these gears being arranged in the mentioned order from the left end of the shaft 65 and splined with this fifth transmission shaft 65 to be rotatable in unison therewith. The shift gear 39 is slidable to a low speed position L meshed with the low speed gear 87, a high speed position H meshed with the high speed gear 90 and a neutral position N meshed with neither of these gears 87, 90. And, the fourth transmission shaft 64, the fifth transmission shaft 65 and the respective gears 39, 86, 87, 89 and 90 mounted on these transmission shafts 64, 65 together constitute the auxiliary speed change device 20.
The right and left differential shafts 21 disposed rearwardly of the fifth transmission shaft 65 include the rear wheel differential device 22 and integrally form a small fifth transmission gear 91 constantly meshed with the transmission gear 26 splined on the right/left rear axles 25 disposed rearwardly of the right/left differential shaft 21.
With the above-described constructions, in order to construct the transmission case 4 for the first use mode, as shown in Figs. 8-10, Fig. 13 and Fig. 22, the first case portion 28 is mounted on e.g. an assembly table, under a posture with its dividing face from the second case portion 29 being positioned upward. And, from the side of this dividing face, the first transmission shaft 16 mounting the wide gear 80, the spacer 92 or the like, the respective transmission shafts 62, 63 and the gears 33, 36, 81-85 of the
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main speed change device 18, the respective operational shafts 35, 38 and the respective shift forks 34, 37 for the main speed change device 18, the third operational shaft 41 and the third shift fork 40 for the auxiliary speed change device 20 and the rear wheel differential device 22, etc. are assembled according to a predetermined procedure. After these assemblies and checking of operations of the components, the second case portion 29 is joined to the dividing face and upper portions of these case portions are bolt connected with each other. Then, to this second case portion 29, there is assembled the fourth case portion 31 in which the differential shafts 21, the rear wheel axles 25, the transmission gear 26 and the side brakes 47 and the operational shafts 48 therefor have been assembled according to a predetermined procedure, with an upper portion of the fourth case portion 31 being bolt-connected to the second case portion 29 and with a lower portion thereof being bolt-connected to the second case portion 29. Then, the lower portions of the fourth case portion 31 and the second case portion 29 are together bolt-connected with the first case portion 29. Thereafter, this assembly is reversed and to the first case portion 29, there is assembled and bolt-connected the third case portion 30 in which the differential shafts 21, the rear axles 25, the transmission gear 26, the shift pawl 42 of the lock mechanism 24, the side brakes 47 and the operational shafts 48 therefor have been assembled according to a predetermined procedure. In this way, the transmission case 4 can be assembled relatively easily.
With the above-described constructions, in order to construct the transmission case 4 for the second use mode, as shown in Figs. 11-13, the first case portion 28 is mounted on e.g. an assembly table, under the posture with its dividing face from the second case portion 29 being positioned upward. And, from the side of this dividing face, the respective transmission shafts 62, 63 and the respective gears 33, 36, 81-85 of the main speed change device 18, the operational shafts 35, 38 and the shift forks 34, 37 for the main speed
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change device 18, the respective transmission shafts 64, 65 and the third shift fork 40 for the auxiliary speed change device 20, the rear wheel differential device 22, the PTO shaft 59 of the PTO unit 53 and the bevel gear 60 ,etc. are assembled according to a predetermined procedure. After these assemblies and checking of operations of the components, to the dividing face, there is assembled the second case portion 29 in which the first transmission shaft 16 mounting the wide gear 80, the bevel gear 74, the shift member 76 for the auxiliary clutch 75, the fifth operational shaft 78 and the fifth shift fork 77 for the shift member 76, and the auxiliary transmission shaft 70 and the bevel gears 71, 72 of the auxiliary transmission line 66 have been assembled according to a predetermined procedure. And, upper portions of these case portions are bolt-connected with each other. Then, to this second case portion 29, there is assembled the fourth case portion 31 in which the differential shaft 21, the rear axles 25, the transmission gear 26, the side brakes 47 and their operational shafts 48 have been assembled according to a predetermined procedure, and an upper portion of the fourth case portion 31 is bolt-connected with the second case portion 29. And, a lower portion of the fourth case portion 31, together with the lower portion of the second case portion 29, are bolt-connected to the first case portion 29. Thereafter, this assembly is reversed and to the first case portion 29, there is assembled and bolt-connected the third case portion 30 in which the differential shafts 21, the rear axles 25, the transmission gear 26, the shift pawl 42 of the lock mechanism 24, the side brakes 47 and the operational shafts 48 therefor have been assembled according to a predetermined procedure. In this way, the transmission case 4 can be assembled relatively easily.
And, in either the first use mode or the second use mode, inside the transmission case 4, even under the non-transmitting condition where the first shift gear 33 and the second shaft gear 36 of the main speed change device 18 are set at the neutral positions N, as long as the main clutch 15 is
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engaged, power from the engine 3 constantly rotates not only the wide gear 80, but also the small gear 81, the first transmission gear 32, the intermediate gear 83 and the large gear 84 which are disposed downwardly of the wide gear 80. With this construction, even when the oil level of the transmission oil has decreased from the reference level OS to the vicinity of the lower ends of the first transmission gear 82, the large gear 84, etc., the transmission oil can be splashed up by the first transmission gear 82, the large gear 84, etc. to be supplied as lubricant oil to the bearings 93 supporting the first transmission shaft 16, the second transmission shaft 62, etc. and the wide gear 80.
Further, under the transmitting condition where the first shift gear 33 or the second shift gear 36 of the main speed change device 18 is set at a position other than the neutral position N, in addition to the power transmission under the non-transmitting condition described above, the power from the engine 3 rotate also the first shift gear 33, the second shaft gear 36, the shift gear 39, the second transmission gear 85 and the third transmission gear 68. With this construction, even when the oil level of the transmission oil has decreased from the reference level OS to the vicinity of the lower ends of the low speed gear 87, the input gear 88 of the rear wheel differential device 22, etc., the transmission oil can be splashed up by the shift gear 39, the third transmission gear 86 or can be splashed away by the first transmission gear 82 or the large gear 84, etc. to be supplied as lubricant oil to the bearings 93 supporting the first transmission shaft 16, the second through fourth transmission shafts 62-64, etc. and the wide gear 80.
And, under the above-described transmitting condition, when the shift gear 39 of the auxiliary speed change device 20 is set to a position other than the neutral position N, in addition to the above-described power transmission, the power from the engine 3 rotates also the low speed gear 87, the fourth transmission gear 89, the high speed gear 90, the input gear 88 of
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the rear wheel differential device 22, the right and left fifth transmission gears 91 and the right and left transmission gears 26. In other words, all the gears 26, 33, 36, 39, 80-91 incorporated within the transmission case 4 are rotated. With this, even when the oil level of the transmission oil has decreased from the reference level OS to the vicinity of the lower ends of the low speed gear 87, the input gear 88 of the rear wheel differential device 22, etc., the transmission oil can be splashed up by the low speed gear 87 or the input gear 88 or can be splashed away by the shift gear 39 or the first shift gear 33 to be supplied as lubricant oil to the bearings 93 supporting the first transmission shaft 16, the second through fifth transmission shafts 62-65, etc. and the wide gear 80.
That is to say, even when due to negligence in oil replenishment, the oil level of the transmission oil has decreased from the reference level OS to the vicinity of the lower ends of the low speed gear 87 or the input gear 88 of the rear wheel differential device 22, during traveling of the vehicle, all the gears 26, 33, 36, 39, 80-91 incorporated in the transmission case 4 are rotated to splash up the transmission oil. Hence, the transmission oil as lubricant oil can be supplied in a relatively stable manner to these gears 26, 33, 36, 39, 80-91 and the bearings 93, etc. thus preventing seizure of the bearings 93.
As shown in Fig. 23, at a rear left upper portion of the transmission case 4, there is communicated and connected a breather 94 forming a ventilation hole (not shown) relative to a plug 95 screwed to a reduced diameter portion 94A formed at the tip end of the breather 94 and having an enlarged diameter portion 94B for preventing leak of the transmission oil through the ventilation hole.
As shown in Figs. 13-17, between the first operational shaft 35 and the first shift fork 34, there is provided a first cam 97 adapted for converting a rotary movement of the first operational shaft 35 into a sliding movement of the first shift fork 34, by means of a pair of cam holes 34a formed at a boss
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portion 34A of the first shift fork 34 and a coupling pin 96 inserted and housed within the first operational shaft 35 to be inserted into these cam holes 34a.
Between the second operational shaft 38 and the second shift fork 37, there is provided a second cam 99 adapted for converting a rotary movement of the second operational shaft 38 into a sliding movement of the second shift fork 37, by means of a pair of cam holes 37a formed at a boss portion 37A of the second shift fork 37 and a coupling pin 98 inserted and housed within the second operational shaft 38 to be inserted into these cam holes 37a.
The first operational shaft 35 projects to the left outer side from the first case portion 28 and a coupling end portion 35A thereof to be operatively coupled with the main speed change lever 17 via the first coupling mechanism LI has a projecting length which is set as a minimum length required for the coupling with the first coupling mechanism LI.
The second operational shaft 38 projects to the left outer side from the first case portion 28 and a coupling end portion 38A thereof to be operatively coupled with the main speed change lever 17 via the second coupling mechanism L2 has a projecting length which is set as a length longer than the projecting length of the coupling end portion 35A of the first operational shaft 35, so as to allow juxtaposition in the right/left direction of the first coupling mechanism LI and the second coupling mechanism L2.
To a side wall of the first case portion 28, there is connected a bracket 101 having a first fixed shaft 100 oriented along the right/left direction. And, to a boss 102 rotatably fitted on this first fixed shaft 100, the main speed change lever 17 is attached to be pivotable to the right/left about a support shaft 103 oriented along the fore and aft direction and formed integrally with the boss 102, with the lever 17 being pivotally urged to the left side of the vehicle body by means of a coil spring 104.
The first coupling mechanism LI includes such components as a
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coupling arm 105 rotatable with the first operational shaft 35 about its axis, a first coupling member 106 fitted on the boss 102 of the first fixed shaft 100 to be pivotable along the fore and aft direction to the inner side of the vehicle body, a coupling link 107 for operatively coupling a first arm portion 106A of the first coupling member 106 with the coupling arm 105. As a first concave portion 17A defined in the main speed change lever 17 is outwardly engaged with a second arm portion 106B of the first coupling member 106 with the urging force of the coil spring 104 at the neutral position of the main speed change lever 17, selective coupling is established between the first coupling mechanism LI and the main speed change lever 17.
The second coupling mechanism L2 includes such components as a coupling arm 108 rotatable with the second operational shaft 38 about its axis, a second coupling member 109 fitted on the boss 102 of the first fixed shaft 100 to be pivotable along the fore and aft direction to the outer side of the vehicle body, a coupling link 110 for operatively coupling a first arm portion 109Aof the second coupling member 109 with the coupling arm 108. As a second concave portion 17B defined in the main speed change lever 17 is outwardly engaged with a second arm portion 109B of the second coupling member 109 with the urging force of the coil spring 104 at the neutral position of the main speed change lever 17, selective coupling is established between the second coupling mechanism L2 and the main speed change lever 17.
With the above-described coupling construction, in operation of the main speed change device 18, at the neutral position N of the main speed change lever 17, in association with a pivotal operation of the main speed change lever 17 therefrom to the right or left, the first concave portion 17Aor the second concave portion 17B of the main speed change lever 17 can be selectively coupled with one of the second arm portion 106B of the first coupling mechanism LI and the second arm portion 109B of the second
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coupling mechanism L2 which are disposed on the right and left sides thereof. And, under such selectively coupled condition, if the main speed change lever 17 is pivoted along the fore and aft direction, the resultant rotational movement of the first operational shaft 35 or the second operational shaft 38 is converted by the associated cam 97, 99 into a sliding movement of the first shift fork 34 or the second shift fork 37, whereby the first shift gear 33 or the second shift gear 36 is slidably operated in the direction corresponding to the operated direction of the main speed change lever 17, thus realizing a speed-changed condition corresponding to the operated position of the main speed change lever 17.
That is to say, as the operational construction of the main speed change device 18 is constructed as the cam type construction wherein the rotational movement of the first operational shaft 35 or the second operational shaft 38 is converted into the sliding movement of the first shift fork 34 or the second shift fork 37, compared with a sliding construction wherein a sliding movement of the first operational shaft 35 or the second operational shaft 38 is used for sliding the first shift fork 34 or the second shift fork 37, due to absence of any operational member which is slid to the lateral outer side of the transmission case 4 during a speed changing operation of the main speed change device 18, the main speed change operating construction can be formed compact in the right/left width thereof, and, the right/left width of the entire transmission case incorporating this main speed changing operational construction can be formed compact accordingly. Consequently, by effectively utilizing free space made available in the right/left direction, it become easier to effect e.g. the power transmission from the engine 3 to the transmission case 4 via the belt type transmission device 14 and the main clutch 15, the operable coupling between the right and left brake pedals 46 and the side brakes 47, the operable coupling between the differential lock pedal 23 and the lock
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mechanism 24, etc.
As shown in Figs. 14-16 and Fig. 18 and Fig. 19, the auxiliary speed change device 20 is constructed as a sliding type device in which the shift fork 37 is slid by a sliding movement of the third operational shaft 41. The third operational shaft 41 projects to the left outer side from the first case portion 29. And, its coupling end 41A to be operatively coupled with the auxiliary speed change lever 19 via a third coupling mechanism L3 has a projecting length which is set for allowing sliding movement between a side wall of the first case portion 28 and the second coupling mechanism L2.
The third coupling mechanism L3 includes a crank arm 112 which is pivotable about a second fixed shaft 111 attached to the bracket 101 and oriented substantially vertical and a coupling pin 113 for operatively coupling a first arm portion 112A of this crank arm 112 with a coupling end 41a of the third operational shaft 41. And, to an engaging concave portion 112a defined in the second arm portion 112B of the crank arm 112, there is operatively coupled a coupling portion 19Aof the auxiliary speed change lever 19 which is pivotable along the fore and aft direction about a third fixed shaft 158 attached to the bracket 101 and oriented along the right/left direction.
With the above operable coupling construction, in operation of the auxiliary speed change device 20, when the auxiliary speed change lever 19 is pivotally operated along the fore and aft direction, this pivotal movement is converted by the crank arm 112 into a sliding movement of the third operational shaft 41. And, this sliding movement slides, via the shift fork 37, the shift gear 39 in the direction corresponding to the operated direction of the auxiliary speed change lever 19, thus realizing a speed-changed condition corresponding to the operated position of the auxiliary speed change lever 19.
And, although the auxiliary speed change device 20 is constructed as the sliding type device described above, since the sliding projection and
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retraction of the third operational shaft 41 relative to the first case portion 29 is effected between the side wall of the first case portion 28 and the second coupling mechanism L2, like the main speed changing construction described above, the auxiliary speed changing construction can be formed compact in the right/left width thereof, so that the entire transmission case including this auxiliary speed changing construction too can be formed correspondingly compact in the right/left width thereof. Consequently, by effectively utilizing free space made available in the right/left direction, it become easier to effect e.g. the power transmission from the engine 3 to the transmission case 4 via the belt type transmission device 14 and the main clutch 15, the operable coupling between the right and left brake pedals 46 and the side brakes 47, the operable coupling between the differential lock pedal 23 and the lock mechanism 24, etc.
Moreover, as the first case portion 28 incorporates therein the main speed change lever 17, the auxiliary speed change lever 19 and the first through third coupling mechanisms L1-L3 for operatively coupling such levers to the main speed change device 18 or the auxiliary speed change device 20, in effecting a maintenance operation to the inside of the transmission case 4 such as gear replacement for the main speed change device 18 or the auxiliary speed change device 20, this can be done relatively easily by detaching the second case portion 29 from the first case portion 28, without having to dismount such speed change levers 17, 19 or the first through third coupling mechanisms L1-L3. As a result, maintenance to the inside of the transmission case 4 can be facilitated.
As shown in Figs. 1-7 and Figs. 24-27, upwardly of the engine 3 mounted at the right/left center of the vehicle body, there are disposed such components as a fuel tank 115 covered with a tank cover 114, a radiator 117 covered with a radiator cover 116, a muffler 118, etc. Forwardly and downwardly of the engine 3, there is disposed a battery 120 covered with a
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front cover 119. Further, immediately below the engine 3, there is disposed a working oil tank 121 which is relatively resistant against adverse influence from muddy water adhesion, by effectively utilizing a space downwardly of the engine 3 made available by disposing this engine at a relatively high position for effectively restricting muddy water adhesion.
Namely, as the battery 120 and the working oil tank 121 which have relatively large weights are disposed on the front side of the vehicle body and downwardly of the engine 3, it is possible to obtain good balance in the fore and aft direction when an implement or the like is connected to the rear side of the vehicle body and to maintain the center of gravity of the vehicle body low, though the engine 3 is disposed at the relatively high position. Consequently, the stability of the vehicle body is improved.
The radiator 117 is configured to introduce air from the right side of the vehicle body and discharge the air toward the muffler 118 disposed on the left side of the vehicle body.
As shown in Fig. 6 and Fig. 24, the working oil tank 121 is disposed between right and left main frames 122 of the vehicle body frame 1 and between front and rear connecting frames 123 interconnecting these main frames 122 and is supported by right and let receiving metal members 124 bolt-connected to the right and left main frames 122.
As shown in Figs. 1-6 and Figs. 25-27, between the engine 3 and a steering post 125 disposed erect rearwardly of the engine 3 and by effectively utilizing space formed therebetween, there are arranged an air cleaner 126, electronic devices (not shown) and also a cover 127 for covering these components.
And, the tank cover 114, the radiator cover 116 and the cover 127 together form an engine hood A for covering the engine 3 from above.
Referring to the cover 127 in details, at a front end upper portion of its back side, there is provided a first engaging portion (not shown) outwardly
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engageable with high precision with a pair of right and left retaining pins 129 provided erect on a support stay 128 attached to a rear upper end of the radiator 117. Further, at a rear end upper portion of the back side, there is provided a second engaging portion (not shown) outwardly engageable with a retaining pin (not shown) projected erect at an upper portion of a support frame 130 provided in the steering post 125, with having looseness in the fore and aft direction. Right and left opposed lower portions of the cover 127 are bolt-connected to the vehicle body frame 1 with a predetermined distance in the fore and aft direction relative to the radiator cover 116. And, at right and left opposed sides of the cover 127, there are formed concave portions 127A for securing foot clearance for a seated driver in order to restrict inadvertent contact with the driver's foot.
The cover 127 includes an upper lid 131 for opening/closing an opening 127a formed at an upper portion and a side lid 132 for opening/closing an opening 127b formed in a left side thereof, with a pair of retaining pawls 131a, 132a provided at the rear ends of the lid being retained in engaging recesses 127c, 127d formed at rear edges of the corresponding openings 127a, 127 and also with front end portions of the lids being secured to the cover 127 by corresponding bolts 133 each having a knob, so that the lids can be readily detached from the cover.
With the above-described construction, for e.g. replacement of a fuse (not shown) as an example of electronic device or component disposed inside the cover 127, by removing the upper lid 131, the fuse replacement can be readily effected through the opening 127a formed at the upper portion of the cover, without having to remove the entire cover 127. Further, for replacement of an element 126A for the air cleaner 126, by removing the side lid 132, the replacement of the element 126Aor detachment of a lid 126B for the air cleaner 126 can be easily effected through the opening 127b formed at the left portion of the cover 127, without having to remove the entire cover
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127.
The air cleaner 126 includes an intake pipe 126C disposed rearwardly and downwardly on the right side of the vehicle body opposite to the left side thereof where the muffler 118 is disposed. Between the engine 3 and the air cleaner 126, there is provided a shielding plate 134 for restricting intake of hot air by the intake pipe 126C. The upper lid 131 defines a group of ventilation openings 131a aligned with each other.
As shown in Figs. 1-6, Fig. 9 and Fig. 113 the belt transmission device 14 includes an output pulley 135 fitted on an extension end of the output shaft 13 of the engine 3, an input pulley 136 fitted on an extension end of the first transmission shaft 16 of the transmission case 4 and a transmission belt 137 entrained about the output and input pulleys 135, 136, in such a manner that the belt extends around the left outer side of the clutch pedal 138 for the main clutch operation disposed on the left forward side of the boarding step 10 on the floor surface of the boarding step 10, so that the belt is offset to the left side of the boarding step 10 so as to bypass a pedal operating portion 139 formed on the boarding step 10. Further, a transmission cover 140 for the belt transmission device 14 is formed bent with an intermediate portion thereof being displaced downward, so that a transmission-wise downstream portion of the transmission cover 140 may be disposed to be aligned on the floor surface of the boarding step 10.
On the right side of the belt transmission device 14 offset toward the center of the boarding step 10 relative to the belt transmission device 14, there is provided a gear pump 142 driven by the power from the engine 3 via a belt type auxiliary transmission device 141 disposed adjacent on the right side of the belt transmission device 14. The gear pump 142 is disposed on the left rear downward side of the engine 3 and upwardly of the floor surface of the boarding step 10.
With the above-described construction, the output shaft 13 of the
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engine 3 and its peripheral portions, as well as the first transmission shaft 16 and the operational shafts 35, 38, 41, 44, 48, 78 of the transmission case 4 and their peripheral portions, the belt transmission device 14, the auxiliary transmission device 141, the gear pump 142, etc. are all disposed at positions higher than the level of the boarding step 10. With this, when this tractor travels on a muddy ground such as a paddy field, it is possible to prevent muddy water splashed with the traveling from adhering and adversely affecting the output shaft 13 of the engine 3 and its peripheral portions, as well as the first transmission shaft 16 and the operational shafts 35, 38, 41, 44, 48, 78 of the transmission case 4 and their peripheral portions, the belt transmission device 14, the auxiliary transmission device 141, the gear pump 142, etc.
Further, as the belt transmission device 14 is disposed on the floor surface of the boarding step 10, it is possible to avoid increase in the right/left width of the vehicle body which would occur if the belt transmission device 14 were disposed on the lateral outer side of the boarding step 10 and also to simplify the supporting structure for the belt transmission device 14. Moreover, although the belt transmission device 14 is disposed on the floor surface of the boarding step 10, it is possible to avoid the inconvenience of the operations of the respective operational pedals 23, 46, 138 provided on the boarding step 10 being interfered with by this belt transmission device 14. Further, compared with a construction in which the transmission-wise downstream portion of the belt transmission device 14 disposed on the floor surface is arranged at a high position spaced apart by a predetermined distance from the floor surface, the above construction can provide better feel of openness to the operator present at the riding operator's section 2.
As shown in Fig. 2, Fig. 4 and Figs. 26*31, at a portion of the support frame 130 rearwardly of the engine 3 and downwardly of the steering wheel 11, there is provided a crank-shaped pivot arm 143 pivotable about an axis
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extending along the right left direction. This pivot arm 143 has its first arm portion 143A operatively coupled with a speed governing lever (not shown) provided on the right side of the engine 3 via an operational cable (an example of “coupling member”) arranged to extend through the engine hood A under a substantially horizontal posture. The pivot arm 143 has also a second arm portion 143B operatively coupled with a coupling arm portion 145A of an accelerator pedal 145 which is provided on the right forward side of the boarding step 10 and pivotable about a rightAeft axis, via a vertically oriented coupling rod 146.
Namely, the operational wire 144 has the advantage of great freedom in the coupling arrangement, but suffers the disadvantage of tending to invite deterioration in its performance due to adhesion of muddy water thereto. Then, this operational wire 146 is disposed at the upper position where adhesion of muddy water splashed by the front and rear wheels 5, 6 hardly occurs and extends through the inside of the engine hood A. With this arrangement, the coupling operation between the pivot arm 143 and the speed governing lever by this operational wire 144 can proceed smoothly.
Moreover, since the operational rod 146 which does not invite deterioration in its performance due to adhesion of muddy water thereto is employed for the operational coupling between the second arm portion 143B of the pivot arm 143 and the coupling arm portion 145A of the accelerator pedal 145, the coupling operation between the pivot arm 143 and the accelerator pedal 145 by the coupling rod 146 can proceed smoothly.
As a result, the coupling operation between the accelerator pedal 145 and the speed governing lever can be carried out smoothly.
The engine 3 incorporates a return spring (not shown) for urging the speed governing lever to return to an engine stop position.
The accelerator pedal 145 is formed of e.g. a round pipe member which is bent to present an “angular-C” shape in its plan view and a hooked
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shape in its side view. The coupling arm portion 145A thereof is connected to the lower end of the coupling rod 146 downwardly of the boarding step 10. As this pedal 145 is stepped on, this step-on operation operates the speed governing lever to the higher speed side against the urging force of the return spring incorporated in the engine 3. Upon release of the step-on operation, the pedal 145 is returned to the low speed side by the urging force of the return spring, together with the speed governing lever.
Downwardly of the steering wheel 11, there is provided an accelerator lever 148 pivotable about a vertical axis in unison with an operational piece 147 which comes into contact with the first arm portion 143A of the pivot arm 143 from one side, which is the low speed side, thereof.
The accelerator lever 148 is formed of e.g. a round pipe member which is bent to present a hooked shape, with upper and lower ends of its vertical support shaft portion 148A being rotatably supported to the support frame 130, and at lower end portion thereof to which the crank-shaped operational piece 147 is fixed, there are fitted a first factional plate 149 interposed between the operational piece 147 and the support frame 130, a pivot plate 150 engaged with the operational piece 147 to be pivotable therewith, a second frictional plate 151 interposed between the pivot plate 150 and the support frame 130, a coil spring 152 for urging the above members to be pressed against each other, a washer 153 receiving the lower end of the coil spring 152. Further, a nut 154 for maintaining these members under the pressed contact condition is screw-fitted to the lever. With these, there is formed a friction type maintaining mechanism 155 for allowing the speed governing lever to be maintained at a desired operated position.
That is, with an operation on the accelerator lever 148, there can be provided a constant speed traveling condition at a desired set speed. And, with the accelerator pedal 145, a speed changing operation to the accelerating side from the set speed is made possible.
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The support frame 130 includes a spring plate 156 which comes into contact with the free end of the operational piece 147 in association with an operation of the accelerator lever 148 to an idling position, thus applying resistance against the operation. With this, the operator can readily recognize arrival of the accelerator lever 148 at the idling position. Hence, this restricts occurrence of inconvenience of inadvertent operation of the accelerator lever 148 to the engine stop position, thus stopping the engine 3.
The coupling rod 146 includes an extension portion 146A extending further upward from the coupling position to the first arm portion 143A of the pivot arm 143 and a gripping portion 146B which is formed by bending the extension end of the extension portion 146A toward the left side of the vehicle body In operation, if mud or grass becomes stuck between the rear face of the boarding step 10 and coupling arm portion 145A of the accelerator pedal 145, thus disabling the speed governing lever, together with the accelerator pedal 145, from returning to the low speed side with the urging force of the return spring of the engine 3 alone, the operator can grip the gripping portion 146B and lifts this up, whereby the speed governing lever, together with the accelerator pedal, can be forcibly returned to the low speed side.
Further, as the gripping portion 146B disposed downwardly of the steering wheel 11 is moved up/down in association with an operation of the accelerator pedal 145 or the accelerator lever 148, the operator can visually confirm the accelerator operated condition.
As shown in Fig. 6 and Fig. 32, the lift cylinder 7 is disposed upwardly of the transmission case 4 under a posture rearwardly lowered to extend along the upper face of the transmission case 4. And, this cylinder 7 is supported by a pair of right and left brackets 101 bolt-connected to the transmission case 4. With this, the shape and the construction of the transmission case 4 can be simplified, compared with a construction in which the lift cylinder 7 is integrated with the transmission case 4.
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Incidentally, in Fig. 6, numeral 157 denotes a pair of right and left mudguard covers for restricting adherence of muddy water to the respective operational shafts 35, 38, 41, 44, 48, 78 and the coupling mechanisms L1-L3 coupled therewith incorporated in the transmission case 4.
[Other embodiment]
The work vehicle can be a rice planting machine, a direct planting machine or a combined harvester, etc.
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Documents:

0511-che-2006 claims-duplicate.pdf

0511-che-2006 descripition(completed)-duplicate.pdf

0511-che-2006 drawings-duplicate.pdf

511-CHE-2006 CORRESPONDENCE OTHERS.pdf

511-CHE-2006 CORRESPONDENCE PO.pdf

511-CHE-2006 FORM-18.pdf

511-CHE-2006 POWER OF ATTORNEY.pdf

511-che-2006-abstract.pdf

511-che-2006-claims.pdf

511-che-2006-complete description.pdf

511-che-2006-correspondance-others.pdf

511-che-2006-diagrams.pdf

511-che-2006-form 1.pdf

511-che-2006-form 3.pdf

511-che-2006-form 5.pdf


Patent Number 229845
Indian Patent Application Number 511/CHE/2006
PG Journal Number 13/2009
Publication Date 27-Mar-2009
Grant Date 20-Feb-2009
Date of Filing 22-Mar-2006
Name of Patentee KUBOTA CORPORATION
Applicant Address 2-47, SHIKITSUHIGASHI 1-CHOME, NANIWA-KU, OSAKA-SHI, OSAKA,
Inventors:
# Inventor's Name Inventor's Address
1 FUJIMOTO, Satoshi C/O. KUBOTA CORPORATION, SAKAI SEIZOSHO, ISHIZUKITAMACHI 64, SAKAI-SHI, OSAKA,
2 EKPOL, Panus c/o The Sian1 Kubota Industry Co., Ltd., 101/19-24, Moo20, Navanakorn, Khlongneung Khlongluang, Pathumtani 12120,
PCT International Classification Number F16H 47/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2005-337856 2005-11-22 Japan