Title of Invention

EXHAUST GAS SENSOR MOUNTING STRUCTURE OF 4-CYCLE ENGINE

Abstract

To facilitate, in an exhaust gas sensor mounting structure of a 4-cycle engine in which an exhaust gas sensor to which a cord extending toward one side is connected is mounted on a side surface of a cylinder head which constitutes a portion of an engine body, a pull-around operation of the cord by setting the extending direction of the cord from the exhaust gas sensor to the fixed direction at the time of mounting the exhaust gas sensor on the cylinder head. [Means for Resolution] A sensor mounting hole 39 for mounting the exhaust gas sensor 38 in a state that a distal end portion of the exhaust gas sensor 38 faces the inside of an exhaust port 34 is formed in a cylinder head 26, and a sensor guard member 49 having a fitting recessed portion 48 is fitted on a rear end portion of the exhaust gas sensor 38 so as to play the role of positioning an extending direction of the cord 45 is mounted on the cylinder head 26. [Selected Drawing] Fig. 3

Full Text

[Designation of Document] Specification [Title of the Invention] EXHAUST GAS SENSOR MOUNTING STRUCTURE OF 4-CYCLE ENGINE [Technical Field] [0001] The present invention relates to an exhaust gas sensor mounting structure of a 4-cycle engine in which an exhaust gas sensor to which a cord extending toward one side is connected is mounted on a side surface of a cylinder head which constitutes a portion of an engine body. [Background Art] [0002] There has been known an exhaust gas sensor mounting structure in which an exhaust gas sensor is mounted on a cylinder head around an exhaust port in patent document 1, for example. [Patent Document 1] JP-A-2004-315430 [Disclosure of the Invention] [Problems that the Invention is to Solve] [0003] Here, although a cord extends from a side surface of a head portion of the exhaust gas sensor, in the exhaust gas sensor disclosed in the patent document 1, the extending direction of the cord from the exhaust gas sensor is not set to the fixed direction at the time of mounting the exhaust gas sensor on the cylinder head and hence; there exists a drawback that a pull-around operation of the cord is difficult. [0004] The present invention has been made under such a circumstance and it is an object of the present invention to provide an exhaust gas sensor mounting structure of a 4-cycle engine which can facilitate a pull-around operation of a cord by fixing the extending direction of the cord from the exhaust gas sensor at the time of mounting the exhaust gas sensor on the cylinder head. [Means for Solving the Problem] [0005] To achieve the above-mentioned object, the invention described in claim 1 is characterized in that, in an exhaust gas sensor mounting structure of a 4-cycle engine in which an exhaust gas sensor to which a cord extending toward one side is connected is mounted on a side surface of a cylinder head which constitutes a portion of an engine body, a sensor mounting hole for mounting the exhaust gas sensor in a state that a distal end portion of the exhaust gas sensor faces the inside of an exhaust port is formed in the cylinder head, and a sensor guard member having a fitting recessed portion which is fitted into a rear end portion of the exhaust gas sensor so as to play the role of positioning an extending direction of the cord is mounted on the cylinder head. The invention described in claim 2 is characterized in that, in addition to the constitution of the invention described in claim 1, the exhaust gas sensor includes a sensor main portion which is mounted on the cylinder head and a cap which is mounted on a rear portion of the sensor main portion in a state that the cord extends from a side surface of the cap, and an outer opening end of an air passage which is communicated with the inside of the sensor main portion and opens at an outer surface of the cap is covered with the sensor guard member which fits the fitting recessed portion thereof on the cap. [0007] Further, the invention described in claim 3 is characterized in that, in addition to the constitution of the invention described in claim 2, the outer opening end of the air passage is arranged above an axis of the sensor mounting hole formed in the cylinder head, a clamper which clamps a middle portion of the cord extending from the exhaust gas sensor is mounted on the engine body below the exhaust gas sensor, and the cord is wired to assume a position which is gradually lowered toward the clamper between the exhaust gas sensor and the clamper. [0008] Here, an oxygen sensor 38 described in an embodiment corresponds to the exhaust gas sensor of the present invention, and a first clamper 56 described in the embodiment corresponds to the clamper of the present invention. [Advantage of the Invention] [0009] According to the invention described in claim 1, by fitting the fitting recessed portion of the sensor guard member mounted on the cylinder head on the rear end portion of the exhaust gas sensor mounted on the cylinder head, the extending direction of the cord from the exhaust gas sensor is set to the fixed direction and hence, it is possible to facilitate a pull-around operation of the cord by setting the extending direction of the cord to the fixed direction while protecting the exhaust gas sensor with the sensor guard member. [0010] Further, according to the invention described in claim 2, the outer opening end of the air passage is covered with the sensor guard member and hence, it is possible to prevent the intrusion of dust or the like from the outside into the inside of the exhaust gas sensor through the air passage using the sensor guard member. [0011] Further, according to the invention described in claim 3, the outer opening end of the air passage is arranged above the axis of the sensor mounting hole, and the middle portion of the cord is clamped by the clamper below the exhaust gas sensor and the cord is wired to assume a position which is gradually lowered toward the clamper and hence, the intrusion of dust, water or the like from the outside into the inside of the exhaust gas sensor through the air passage can be prevented more effectively and, at the same time, it is possible to prevent water which moves on the cord from flowing toward a cap side. [Best Mode for Carrying Out the Invention] [0012] Hereinafter, a mode for carrying out the present invention is explained based on one embodiment of the present invention shown in attached drawings. [0013] Fig. 1 to Fig. 4 are views showing one embodiment of the present invention, wherein Fig. 1 is a side view of a motorcycle, Fig. 2 is an enlarged side view of an essential part of an engine body. Fig. 3 is an enlarged cross-sectional view taken along a line 3-3 in Fig. 2, and Fig. 4 is an enlarged cross-sectional view taken along a line 4-4 in Fig. 2. [0014] Here, in the explanation of the embodiment made hereinafter, front and rear directions and left and right directions are directions in a state that a rider faces the advancing direction of the motorcycle. First of all, in Fig. 1, a vehicle body frame F of the motorcycle includes a head pipe 12 which steerablly supports a front fork 11 for supporting a front wheel WF, a main frame 13 which extends in the rearward and downward direction from the head pipe 12, and a seat rail 14 which extends in the rearward and upward direction and is contiguously mounted on a lower portion of the main frame 13. A steering handle 15 is joined to an upper portion of the front fork 11, and a seat 16 on which a rider sits is arranged above the seat rail 14 in an openable manner. [0016] A storing box 17 which is covered with the seat 16 from above is arranged at a front lower portion of the seat 16, a fuel tank 18 is arranged at a rear lower position of the seat, and the storing box 17 and the fuel tank 18 are respectively supported on the seat rail 14. [0017] On the main frame 13, a power unit P which is constituted of a 4-cycle engine E and a power transmission device T which changes an output of the engine E in a continuously variable manner and performs a speed-reduction operation is supported in a suspended manner in a state that the power unit P is arranged below the vehicle body frame F. A rear wheel WR is pivotally supported between rear portions of a pair of swing arms 19... which has front end portions thereof rockably supported on the power unit P. An output of the power unit P is transmitted to the rear wheel WR by way of a chain transmission means 20 arranged on a left side of the vehicle body fame F. A rear cushion 21 is arranged between the swing arms 19... and the seat rail 14. [0018] Further, the vehicle body frame F, the engine E in the power unit P, the storing box 17 and the fuel tank 18 are covered with a vehicle body cover 22. [0019] In Fig. 2, an engine body 23 of the engine E in the power unit P includes a crankcase 24, a cylinder block 25 which is joined to a front end of the crankcase 24 in a frontwardly inclined posture, and a cylinder head 26 which is joined to a front end of the cylinder block 25. [0020] A crankshaft 27 which has an axis extending in the lateral direction is rotatably supported on the crankcase 24, and the power transmission device T is incorporated in a power transmission case 28 (see Fig. 1) which adopts a portion of the crankcase 24 as a constitutional element thereof. [0021] An intake system 30 is connected to an intake port 29 which opens at an upper side surface of the cylinder head 26. The intake system 30 is constituted of an intake pipe 31 which has a downstream end thereof connected to the cylinder head 26 in a communicable manner with the intake port 29 and is formed in a frontwardly curved shape, a throttle body 32 (see Fig. 1) which is arranged above the cylinder head 26 and has a downstream end thereof connected to an upstream end of the intake pipe 31, and an air cleaner 33 which is arranged above a front portion of the throttle body 32 and to which an upstream end of the throttle body 32 is connected. On the throttle body 32, a fuel injection valve (not shown in the drawing) is mounted. [0022] An exhaust system 35 is connected to an exhaust port 34 which opens at a lower side surface of the cylinder head 26. The exhaust system 35 is constituted of an exhaust pipe 36 (see Fig. 1) which has an upstream end thereof connected to the cylinder head 26 in a communicable manner with the exhaust port 34 and extends rearwardly along a right-and-lower side portion of the power unit P, and an exhaust muffler 37 (see Fig. 1) which is arranged on a right side of the rear wheel WR and is connected to a downstream end of the exhaust pipe 36. [0023] In Fig, 3, on the cylinder head 26, an oxygen sensor 38 which constitutes an exhaust gas sensor is mounted for detecting oxygen density in an exhaust gas which flows through the exhaust port 34. For mounting the oxygen sensor 38 on the cylinder head 26, a sensor mounting hole 3 9 which is communicated with the exhaust port 34 is formed in a right surface of the cylinder head 26. The oxygen sensor 38 includes a sensor main portion 41 having a housing 40 which is mounted on the cylinder head 26 by threadedly engaging a distal end side thereof with the sensor mounting hole 39, and a cap 42 which is detachably mounted on a rear portion of the sensor main portion 41. The sensor main portion 41 is mounted on the cylinder head 26 in a state that a distal end portion of the sensor main portion 41 faces the exhaust port 34. [0024] The housing 40 is formed in a cylindrical shape. An engaging portion 40a which projects in the radially outward direction andhas a hexagonal transverse cross sectional shape, for example, is formed on an axially middle portion of the housing 4 0 for allowing a rotary tool to engage with the engaging portion 40a. Male threads 43 which threadedly engage with the sensor mounting hole 39 which constitutes a threaded hole are formed on an outer surface of the housing 40 on a side closer to a distal end side of the housing 40 than the engaging portion 40a. [0025] The cap 42 is made of a resilient material such as rubber, for example. The cap 42 is integrally formed of a bottomed cylindrical portion 42a which is resiliently fitted in a rear portion of the housing 40 of the sensor main portion 41 and a pair of cylindrical projections 42b, 42c which projects in the sideward direction from a rear portion of the bottomed cylindrical portion 42a. Both projections 42b, 42c project toward both sides from the rear portion of the bottomed cylindrical portion 42a in a state that the projections 42b, 42c have axes thereof arranged on a diametral line of the bottomed cylindrical portion 42a. [0026] One projection 42b out of both projections 42b, 42c forms an air passage 44 which introduces air into the inside of the sensor main portion 41 therein. The air passage 44 opens at an outer end of the projection 42b, that is, an outer surface of the cap 42. A cord 45 is connected to another projection 42c out of both projections 42b, 42c in a state that the cord 45 extends in the sideward direction from the projection 42c. A connection terminal 4 6 which is arranged in the inside of the cap 42 in a connected state with the cord 45 is electrically connected with a connection terminal 47 on a side of the sensor main portion 41 when the cap 42 is fitted on a rear portion of the sensor main portion 41. Further, the cord 45 extends toward a side opposite to an opening portion of the air passage 44 from a rear side surface of the oxygen sensor 38, that is, a side surface of the cap 42. Further, a sensor guard member 4 9 having a fitting recessed portion 48 which is fitted into a rear end portion of the oxygen sensor 38 so as to play the role of positioning the extending direction of the cord 4 5 is mounted on the cylinder head 26, For mounting the sensor guard member 4 9 on the cylinder head 26, a boss portion 51 having a flat mounting seat 50 on a projecting end thereof is integrally formed on a right side surface of the cylinder head 26 at a front and oblique upper position of the mounting hole 39 in a projecting manner. A bottomed threaded hole 52 which opens at a mounting seat 50 is formed in the boss portion 51 and/ at the same time, a positioning projection 53 which projects from the mounting seat 50 is integrally formed on the boss portion 51 at a position offset from the threaded hole 52, [0028] The sensor guard member 49 integrally includes a mounting plate portion 4 9a which is brought into contact with the mounting seat 50, a raised plate portion 4 9b which has a proximal end portion thereof contiguously formed with the mounting plate portion 49a at a right angle and extends toward a side away from the mounting seat 50, a pair of side plate portions 49c, 49d which is contiguously formed with both sides of a distal-end side of the raised plate portion 49b at a right angle and faces each other in an opposed manner, and a push plate portion 49e which extends in the direction orthogonal to both side plate portions 49c, 49d and is contiguously formed with a distal end of the raised plate portion 49b at a right angle. A bolt 54 which passes through the mounting plate portion 49a threadedly engages with the threaded hole 52, and the positioning projection 53 is fitted in a positioning hole 55 formed in the mounting plate portion 49a. [0029] Further, both side plate portions 49c, 49d and the push plate portion 49e form the fitting recessed portion 48 in a cooperative manner. The sensor guard member 49 is mounted on the cylinder head 26 by sandwiching the projection 42b which forms the air passage 44 therein with both side plate portions 49c, 49d and by bringing the push plate portion 49e into contact with the projection 42b on a side opposite to the cylinder head 26. As described above, the air passage 44 of the oxygen sensor 38 extends in the frontward and upward direction in a state that a portion of the cap 42 is fitted in the fitting recessed portion 48. Here, the outer opening end of the air passage 44 is arranged above an axis C (see Fig. 2) of the sensor mounting hole 39 and hence, the outer opening end of the air passage 44 is covered with a raised plate portion 49b of the sensor guard member 49 from a front side thereof. [0030] On the other hand, in a state that the sensor guard member 49 which fits the fitting recessed portion 48 on the cap 42 is mounted on the cylinder head 26, the cord 45 extends in the direction opposite to the air passage 44, that is, in the rearward and downward direction from the cap 42. The first clamper 56 which clamps a middle portion of the cord 45 is mounted on the cylinder block 25 of the engine body 23 below the oxygen sensor 38. [0031] To explain this embodiment also in conjunction with Fig. 4, the first clamper 56 is formed by bending a rod material, and is fixedly mounted on a support plate 58 which is fastened to a right side surface of the cylinder bock 25 using bolts 57 by welding or the like. Further, the first clamper 56 includes an approximately C-shape formed fitting clamping portion 56a which is resiliently fitted on the cord 45 from a side, and a contact support portion 56b which i3 arranged behind the fitting clamping portion 56a and is brought into contact with the cord 45, The contact support portion 56b is configured to be brought into contact with an inner side surface of the cord 45 at a position offset to the outside from the center of the fitting clamping portion 56a along the lateral direction of the cylinder block 25. [0032] Here, the cord 45 is wired to assume a position which y is gradually lowered toward the first clamper 56 between the oxygen sensor 38 and the first clamper 56. [0033] A support plate 60 is fastened to a left side surface of the cylinder block 25 using bolts 59. A guard member 62 which covers an oil temperature sensor 61 mounted on a right lower portion of the cylinder block 25 from a front side and-below is fixedly mounted on the support plate 60 by welding or the like. Both support plates 58, 60 are connected with each other by a connecting bar 63, and axes of the bolts 57, 59 are aligned with each other. [0034] To focus on the constitution shown in Fig. 2, the cord 45 which is clamped by the first clamper 56 is clamped and curved upwardly by a second clamper 65 which is fastened to a lower portion of the crankcase 24 using bolts 64 behind the first clamper 56 and, further, the cord 45 is clamped by a third clamper 67 which is fastened to a lower portion of the crankcase 24 using bolts 66 above the second clamper 65. [0035] As shown in Fig. 1, the cord 4 5 extends rearwardly than the storage box 17 behind the third clamper 67, and is connected to a control unit 70 stored in the inside of the vehicle body cover 22 arranged between the storage box 17 and the fuel tank 18. [0036] Next, the manner of operation of this embodiment is explained. The sensor mounting hole 39 for mounting the oxygen sensor 38 in a state that a distal end portion of the oxygen sensor 38 faces the inside of the exhaust port 34 is formed in the cylinder head 26, The sensor guard member 49 having the fitting recessed portion 48 which is fitted on a rear end portion of the oxygen sensor 38 and plays a role of positioning the extending direction of the cord 4 5 is mounted on the cylinder head 26. Accordingly, in a state that the oxygen sensor 38 and the sensor guard member 49 are mounted on the cylinder head 26, the extending direction of the cord 45 from the oxygen sensor 38 is set to the fixed direction and hence, it is possible to facilitate a pull-around operation of the cord 45 by setting the extending direction of the cord 45 to the fixed direction while protecting the oxygen sensor 38 with the sensor guard member 49. [0037] Further, the oxygen sensor 38 includes the sensor main portion 41 which is mounted on the cylinder head 26 and the cap 42 which is mounted on the rear portion of the sensor main portion 41 in a state that the cord 45 extends from a side surface of the cap 42. The outer opening end of the air passage 44 which opens at the outer surface of the cap 42 through the inside of the sensor main portion 41 is covered from the front side with the raised plate portion 49b of the sensor guard member 49 being in a state that the fitting recessed portion 48 is fitted on the cap 42 and hence, it is possible to prevent the intrusion of dust or the like from the outside into the inside of the oxygen sensor 38 through the air passage 44 using the sensor guard member 49. [0038] Further, the outer opening end of the air passage 44 is arranged above the axis C of the sensor mounting hole 39 formed in the cylinder head 26 for mounting the oxygen sensor 38, the first clamper 56 which clamps the middle portion of the cord 45 extending from the oxygen sensor 38 is mounted on the cylinder block 25 of the engine body 23 below the oxygen sensor 38, and the cord 45 is wired to assume a position which is gradually lowered toward the first clamper 56 between the oxygen sensor 38 and the first clamper 56. Accordingly, the intrusion of dust, water or the like from the outside into the inside of the oxygen sensor 38 through the air passage 44 can be prevented more effectively and, at the same time, it is possible to prevent water which moves on the cord 45 from flowing into the cap 42, that is, the oxygen sensor 38 side. [0039] Although the embodiment of the present invention has been explained heretofore, the present invention is not limited to the above-mentioned embodiment, and various design modifications can be made without departing from the present invention described in Claims• [Brief Description of the Drawings] [0040] [Fig. 1] A side view of a motorcycle. [Fig. 2] An enlarged side view of an essential part of an engine body. [Fig. 3] An enlarged cross-sectional view taken along a line 3-3 in Fig. 2. [Fig. 4] An enlarged cross-sectional view taken along a line 4-4 in Fig. 2. [Description of Reference Numerals and Signs] [0041] 23: engine body 26: cylinder head 34: exhaust port 38: oxygen sensor constituting exhaust gas sensor 39: sensor mounting hole 41: sensor main portion 42: cap 44: air passage 45: cord 48: fitting recessed portion 49: sensor guard member 56: clamper [Designation of Document] Claims [Claim 1] An exhaust gas sensor mounting structure of a 4-cycle engine in which an exhaust gas sensor (38) to which a cord (45) extending toward one side is connected is mounted on a side surface of a cylinder head (26) which constitutes a portion of an engine body (23), wherein a sensor mounting hole (39) for mounting the exhaust gas sensor (38) in a state that a distal end portion of the exhaust gas sensor (38) faces the inside of an exhaust port (34) is formed in the cylinder head (26) , and a sensor guard member (49) having a fitting recessed portion (48) which is fitted on a rear end portion of the exhaust gas sensor (38) so as to play the role of positioning an extending direction of the cord (45) is mounted on the cylinder head (26) . [Claim 2] An exhaust gas sensor mounting structure of a 4-cycle engine according to claim 1, wherein the exhaust gas sensor (38) includes a sensor main portion (41) which is mounted on the cylinder head (26) and a cap (42) which is mounted on a rear portion of the sensor main portion (41) in a state that * the cord (45) extends from a side surface of the cap (42) , and an outer opening end of an air passage (44) which is communicated with the inside of the sensor main portion (41) and opens at an outer surface of the cap (42) is covered with the sensor guard member (49) which fits the fitting recessed portion (48) thereof on the cap (42). [Claim 3] An exhaust gas sensor mounting structure of a 4-cycle engine according to claim 2, wherein the outer opening end of the air passage (44) is arranged above an axis of the sensor mounting hole (39) formed in the cylinder head (26) , a clamper (56) which clamps a middle portion of the cord (45) extending from the exhaust gas sensor (38) is mounted on the engine body (23) below the exhaust gas sensor (38), and the cord (45) is wired to assume a position which is gradually lowered toward the clamper (56) between the exhaust gas sensor (38) and the clamper (56).

Documents:

2993-CHE-2007 AMENDED PAGES OF SPECIFICATION 09-08-2012.pdf

2993-CHE-2007 AMENDED CLAIMS 09-08-2012.pdf

2993-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 09-08-2012.pdf

2993-CHE-2007 FORM-3 09-08-2012.pdf

2993-CHE-2007 OTHER PATENT DOCUMENT 09-08-2012.pdf

2993-CHE-2007 CORRESPONDENCE OTHERS 20-01-2012.pdf

2993-che-2007-abstract.pdf

2993-che-2007-claims.pdf

2993-che-2007-correspondnece-others.pdf

2993-che-2007-description(complete).pdf

2993-che-2007-drawings.pdf

2993-che-2007-form 1.pdf

2993-che-2007-form 18.pdf

2993-che-2007-form 26.pdf

2993-che-2007-form 3.pdf

2993-che-2007-form 5.pdf

2993-che-2007-other documents.pdf