Title of Invention

DRIVING APPARATUS FOR RAILWAY ROLLING STOCKS

Abstract A driving apparatus for railway rolling stocks includes a boss member (10) fit on an end portion of an axle (1) , a wheel (9) at a drive side fit on an outer circumference of the boss member, a wheel (3) opposite the drive side fit on another end portion of the axle, a gear (2) fit on the outer circumference of the boss member, in a position nearer to a central portion of the axle than the wheel at the drive side, a main motor (4) arranged in a space between the wheels, in parallel to the axle, and a pinion (5) fit on a shaft end (4a) of the main motor, the pinion meshing with the gear, for the main motor to have increased torque with an enlarged capacity, affording to secure permissible torque transmission at fitting portions of and between gear and wheel and permissible torque transmission at fitting portions of and between wheel and axle, allowing wheel replacement work without needing a removal of the gear, for a facilitated replacement of wheel and gear.
Full Text DRIVING APPARATUS FOR RAILWAY ROLLING STOCKS
BACKGROUND OF THE INVENTION 1- Field of Art
The present invention relates to a driving apparatus for railway rolling stocks-2. Description of Relevant Art
For the railway rolling stock, recent years have observed increasing traffic volumes, in particular of freight shipments abroad shipping a great amount of cargo at a time, with increasing needs for a motive power locomotive for traction with an increased capacity. For electric locomotives, in general, the driving apparatus is configured with a main motor arranged parallel to an axle, a pinion fit on an end of an output shaft of the main motor, and a gear meshing therewith and fit on the axle, for transmission of torque from the main motor to the axle
Such the configuration of driving apparatus for railway rolling stocks employs a structure for' a distance between a center axis of the main motor's shaft and a center axis of the axle to be a center to-center distance between the pinion and the gear, where the axle is provided with axle bearings, which are fixed in positions to both ends of the main motor at a prescribed spacing from each other, so’ that the gear as well as the pinion can keep a prescribed dimensional relationship to the main motor. The gear fit on the axle is. adapted for transmission of torque transmitted thereto from the main motor through the pinion, to the axle. Thus, for a pair of fit portions of and between the gear and the axle, their diameters, fit length

in between, and tightening margin in between are determined so that they can be kept from slipping, even with an abnormality of the main motor applying them greater torque than specified maximum torque. To this point, as torque is transmitted from the main motor through the pinion and the gear to the axle, as described, and therefrom to wheels, the pair of fit portions of and between the gear and the axle should have their diameters, fit length, and tightening margin determined to endure transmission of a magnitude of torque that allows the wheels to roll on rail surfaces, by friction of the rail surfaces,
For a respective pair of fit portions of and between the axle and the gear and wheels, assuming a constant tightening margin in between, the magnitude of transmittable torque is proportional to the fit surface area, so that the diameters and/or the fit length of the paired fit portions should be increased, as the main motor has greater torque. As the magnitude of torque to be output from the main motor increases, the diameter as well as the length of the main motor is to be increased. Teeth of the gear should also be rendered stronger, needing a greater tooth width.
Such being the case, for an increased output of electric locomotive, it is necessary to make greater the size of the main motor and the teeth width of the gear, as well as fit portions of and between the gear and the axle, and fit portions of and between the axle and the wheels. On the other hand, the rail gauge is fixedly predetermined, so that the driving apparatus to be assembled within a space between a wheel at the drive side and a wheel opposite the drive side receives a restriction from

the axial length of the axle, and unable to be longer than a prescribed length. Therefore, for greater torque to be transmitted by fitting the gear and the wheels, it is necessary to increase diametrical dimensions of associated fit portions, as a matter of course.
Fig. 6 shows a driving apparatus for locomotives according to a related art. According to this related art, the driving apparatus for locomotives includes a gear 102 fit on an axle 101, and a pair of wheels 103 fit on both end portions of the axle 101. A main motor 104 is arranged in position, with its shaft 104a in parallel to the axle 101. The main motor 104 is fixed at a distance off from the axle 101, by use of axle bearings 105. The main motor 104 has a pinion 106 fit on an end of the shaft 104a, and the pinion 106 has a center-to-center distance held to the gear 102 by the axle bearings 105. The gear 102 and the pinion 106 are commonly covered by a gear casing 107, for a hermetical sealing from outside air. It is noted that journal bearings 20 are put on both ends of the axle 1, at outer sides of the wheels 3 and 9.
Fig. 7 shows a driving apparatus for railway rolling stocks as addressed to high-power locomotives according to another related art. According to this related art, the driving apparatus for railway rolling stocks includes a large-capacity main motor 104 arranged in position, with its shaft 104a in parallel to an axle 101. The main motor 104 is fixed at a distance off from the axle 101, by use of axle bearings 105. The main motor 104 has a pinion 106 fit on an end of the shaft 104a, and the pinion 106 has a center-to-center distance held to a gear

102 by the axle bearings 105. The gear 102 and the pinion 106 are commonly covered by a gear casing 107, for a hermetical sealing from outside air. This structure is analogous to that of that related art shown in Fig, 6_ However, in this related art, for great output torque from the large capacity main motor 104 to be transmitted between the gear 102 and a wheel 108 at the drive side without slips along their fit surfaces, the wheel 108 is formed with a boss portion 108a elongated along the axle 101. And, for a fitting to the axle 101, the gear 102 is configured to fit on an outer circumferential surface of the boss portion 108a elongated as a fit portion of the wheel 108 in the axial direction of the axle 101. According to this related art, although the gear 102 has an identical fit length to the boss portion 108a, their fit portions have increased diameters, allowing the increases in diameters of the fit portions to transmit the more greater torque.
However, for the driving apparatus for railway rolling stocks as addressed to high-power locomotives, the fitting between the wheel 108 and the axle 101 employs a structure with an elongate total fit length and an increased tightening margin, which constitutes a difficulty in press fitting, requiring extreme caution, and if they are press fit with overlooked minor burrs or scrapes left at the fitting inlet, the fit surfaces may be injured, giving damages to the axle 101 in most cases. The press fitting of the wheel 108 onto the axle 101 is done, not simply in the manufacture, but also in the way of use at the user, where replacement of a wheel is performed, as the wheel is worn by a constant rate of abrasion, and to be carried out

after a service about one-year in an earliest case, together with a pulling-out, which affects more adversely, as the wheel boss portion 108a has an increased fit length. Further, for the wheel 108 as a component to be worn and replaced with lapse of a constant term of use as described, the boss portion 108a to be fit with an increased length may render the manufacturing cost of wheel 108 higher, with increased expenses for wheel replacement and maintenance, either, as a problem.
Patent document"‘1 to be referred to:
Japanese Patent Application Laying-Open Publication No. 10-278783
Patent document-2 to be referred to:
Japanese Patent Application Laying-Open Publication No. 2003-327117
SUMMARY OF INVENTION
The present invention has been devised in view of such points in the relevant art. It therefore is an object of the present invention to provide a driving apparatus for railway rolling stocks in which a main motor can have increased torque with an enlarged capacity, affording to secure permissible torque transmission at fitting portions of and between gear and wheel and permissible torque transmission at fitting portions of and between wheel and axle, allowing wheel replacement work without needing a removal of the gear’ for a facilitated replacement of wheel and gear.
According to an aspect of the present invention, a driving apparatus for railway rolling stocks comprises an axle, a boss

member fit on an end portion of the axle, a wheel at a drive side fit on an outer circumference of the boss member, a wheel opposite the drive side fit on another end portion of the axle, a gear fit on the outer circumference of the boss member, in a position nearer to a central portion of the axle than the wheel at the drive side, a main motor arranged in a space between the wheels, in parallel to the axle, and a pinion fit on a shaft end of the main motor, the pinion meshing with the gear.
According to the aspect of the present invention, for a wheel to fit on an axle, the portion of a boss is configured as a divided structure, whereby a gear, which would have been fit on a boss portion of a wheel in a related art, is allowed to fit on an outer circumference of a boss member as divided-Further, according to the aspect of the present invention, in comparison with the related art in which the boss portion must be elongate in an axial direction of the axle for the wheel to fit thereon, the boss member as divided from the wheel can have simply a wheel-fitting boss portion of the boss member per se adapted for the wheel to fit thereon, allowing the wheel to fit simply on an outer circumference of the boss member, affording to provide the fitting portion with an expanded diameter with an enlarged surface area for the fitting, resulting in possible transmission of greater torque.
Further, according to the aspect of the present invention, the boss member has one half thereof configured for the wheel to fit thereon and the other part thereof configured for the gear to fit thereon, whereby for wheel replacement, the removal work as well as attachment work for the wheel as a single member

to be removed from the boss’ member can be performed with the boss member left as it is fit on the axle, without needing the gear to be removed together even in replacement of the wheel, thus affording a far enhanced workability in replacement work of the wheel, allowing for a reduced maintenance cost. In addition, of the wheel as a consumable supply, a boss portion occupying a great volume is separated, the portion being little abrasive, permitting simply an outer wheel portion to be replaced, allowing for a reduction effect in price of the wheel, as well-
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a sectional view of a driving apparatus for railway rolling stocks according to a first embodiment of the present invention.
Fig, 2 is a sectional view of a driving apparatus for railway rolling stocks according to a second embodiment of the present invention.
Fig. 3 is a sectional view of a driving apparatus for railway rolling stocks according to a third embodiment of the present invention.
Fig. 4 is a sectional view of a driving apparatus for railway rolling stocks according to a fourth embodiment of the present invention.
Fig. 5 is a sectional view of a driving apparatus for railway rolling stocks according to a fifth embodiment of the present invention.
Fig. 6 is a sectional view of a driving apparatus for

railway rolling stocks according to a related art.
Fig, 7 is a sectional view of a driving apparatus for railway rolling stocks according to another related art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
There will be described below the preferred embodiments of the present invention into details with reference to the accompanying drawings. Like members or elements will be designated by like reference characters.
(First Embodiment)
Fig, 1 shows a driving apparatus for railway rolling stocks according to a first embodiment of the present invention. In this driving apparatus for railway rolling stocks, a wheel 9 at the drive side is fit on one end portion of an axle 1, and a wheel 3 opposite the drive side is fit on the other end portion of the axle 1. A main motor 4 is arranged in position, with its shaft 4a in parallel to the axle 1. The main motor 4 is fixed at a distance off from the axle 1 by axle bearings 5, A pinion 6 is fit on an end of the shaft 4a of the main motor 4, and for this pinion 6 to be put in meshing engagement with a gear 2 fit on the axle 1, a center-to-center distance between the gear 2 and the pinion 6 is held by the axle bearings 5. The gear 2 and the pinion 6 are configured to be commonly covered by a gear casing 1, for a hermetical sealing from outside air.
Further’- this driving apparatus for railway rolling stocks includes a boss member 10 configured to be elongate in the axial direction of the axle 1, and fit on the axle 1* The boss member 10 has a wheel-fitting boss portion lOA as its one

half in the axial direction and a gear-fitting boss portion lOB as its other half in the axial direction, with a setting D > d, where D is an outside diameter of the wheel-fitting boss portion lOA, and d is an outside diameter of the gear-fitting boss portion lOB. For a fit portion of the wheel 9 on the wheel-fitting boss portion lOA, the diameter D is set to be adequate in size for transmission of large torque from the main motor 4 . Also for a fit portion of the gear 2 on the gear-fitting boss portion lOB, the diameter d is set to be adequate in size for transmission of large torque from the main motor 4 through the pinion 6, It is noted that journal bearings 20 are put on both ends of the axle 1, at outer sides of the wheels 3 and 9.
For railway rolling stocks, both a wheel 9 at the drive side and a wheel 3 opposite the drive side are worn by their friction with rails, as they run, needing their replacement every constant interval. In this respect, according to the present embodiment, the replacement is facilitated, in particular of the wheel 9 at the drive side, which is fit on the wheel-fitting boss portion lOA of the boss member 10, as a single member to be pulled off from the wheel-fitting boss portion lOA for replacement thereof.
Such being the case, according to the present embodiment, the replacement of wheel 9 is very facile, in comparison with the driving apparatus for railway rolling stocks as addressed to high-power locomotives according to the related art shown in Fig. 7, in which the wheel 108 is integrally formed with the boss portion 108a, on which the gear 102 also is fit, disabling the wheel 108 to be pulled off as a single member, in addition

to that the wheel 108 has an elongate boss-fit length constituting a difficulty in work to pull off the wheel 108 from the axle 101. Further, the separate configuration of wheel 9 and boss member 10 permits the wheel 9 to be reduced in size as a consumable supply that can be manufactured at a low price in comparison with a wheel in the related art, allowing for reduction in both manufacturing cost and maintenance cost.
(Second Embodiment)
Description is now made of a driving apparatus for railway rolling stocks according to a second embodiment of the present invention, with reference to Fig. 2. In the present embodiment, which includes a boss member 11 fit on one end portion of an axle 1, the boss member 11 has a wheel-fitting boss portion llA as one half thereof adapted for a wheel 9 at the drive side to fit thereon, and a gear-fitting boss portion IIB as the other half thereof adapted for a gear 2 to fit thereon. The present embodiment is different from the first embodiment in that dimensions of a fitting diameter Dl of the wheels-fitting boss portion llA and a fitting diameter dl of the gear-fitting boss portion llB are set such that Dl The present embodiment permits the wheel 9 to be pulled off toward the outside of the axle 1 as a leftward direction in the state shown in Fig. 2, for replacement of the wheel 9_ Also for the gear 2 to be replaced, as necessary, it permits, after removal of the wheel 9, the gear 2 to be pulled off in

the leftwardly outer direction of the axle 1, like the wheel 9. Therefore, the present embodiment permits, even for the gear 2, a completion of replacement without having the boss member 11 pulled off from the axle 1, thus allowing for a facilitated replacement of wheel 9 as well as a facilitated replacement of gear 2, as an advantage -
(Third Embodiment)
Description is now made of a driving apparatus for railway rolling stocks according to a third embodiment of the present invention, with reference to Fig, 3, In the present embodiment, which includes a boss member 12 fit on one end portion of an axle 1, the boss member 12 has a wheel-fitting boss portion 12A as one half thereof adapted for a wheel 9 to fit thereon, a gear-fitting boss portion 12B as the other half thereof adapted for a gear 2 to fit thereon, and a peripheral projection 12C formed on an end of the gear-fitting boss portion 12B, at the side nearer to a central portion of the axle, for the gear 2 to be received by the projection 12C for a positioning to keep it from intruding over there into a region at the side of an axle bearing 5. The gear 2 has a fitting recess formed in a stepped shape so as to fit on the gear-fitting boss portion 12B and the projection 12C, with a setting for the lateral side of the gear 2 to be flush with the end face of the boss member 12 in their fit state.
It is noted that in the embodiment shown in Fig. 3, for configuration of other parts than described, like elements to the second embodiment shown in Fig. 2 are designated by like reference characters. Further, in the present embodiment.

dimensions of a fitting diameter D2 of the wheel-fitting boss portion 12A and a fitting diameter d2 of the gear-fitting boss portion 12B are set such that D2 According to the present embodiment in which the boss member 12 fit on one end portion of the axle 1 is formed with the wheel-fitting boss portion 12A, the gear-fitting boss portion 12B, and the projection 12C, the replacement of wheel 9 is very facilitated, like the first embodiment, permitting the wheel 9 to be reduced in size as a consumable supply that can be manufactured at a low price in comparison with a wheel in a related art, while allowing for a facilitated replacement of the gear 2 also, as an advantage, and an exact and facile positioning of the gear 2, as another advantage-(Fourth Embodiment)
Description is now made of a driving apparatus for railway rolling stocks according to a fourth embodiment of the present invention, with reference to Fig. 4. The present embodiment features a boss member 13. The boss member 13 is configured, like the third embodiment, with. a wheel-fitting boss portion ISA as one half thereof, a gear-fitting boss portion 13B as the other half thereof, and a peripheral projection 13C formed on an end thereof, but is different from the third embodiment in that an outside diameter D3 of the wheel-fitting boss portion 13A and an outside diameter d3 of the gear-fitting boss portion

13B are set equal to each other (D3 - d3) , thus eliminating the step. It is noted that in the embodiment shown in Fig, 4, for configuration of other parts than described, like elements to the third embodiment shown in Fig. 3 are designated by like reference characters -
According to the present embodiment, the gear 2 can be set in position in the press fitting direction (axial direction) by a concavo-convex relationship, like the third embodiment, and the wheel 9 to be press-fit until it contacts the lateral side of the gear 2 can be set in position in the press fitting direction per se, thus affording actions and effects similar to those in the third embodiment, allowing for a simplified assembly work relative to the third embodiment, as an advantage.
(Fifth Embodiment)
Description is now made of a driving apparatus for railway rolling stocks according to a fifth embodiment of the present invention, with reference to Fig. 5. In the driving apparatus for railway rolling stocks according to the present embodiment, a boss member 13 similar to that in the fourth embodiment is fit on one end portion of an axle 1, and a gear 2 and a wheel 9 at the drive side are both fit on the boss member 13. The present embodiment features a divided structure of a wheel 15 opposite the drive side at the other end portion of the axle 1, where it includes a boss member 16 fit on the other end portion of the axle 1, and the boss portion 16 has a wheel-fitting boss portion 16A thereof configured for the wheel 15 opposite the drive side to fit thereon, and a peripheral projection 16B thereof configured for a positioning of the wheel 15 _ It is noted

that in the embodiment shown in Fig- 5, for configuration of other parts than described, like elements to the fourth embodiment shown in Fig. 4 are designated by like reference characters.
In the present embodiment, the boss member 13 for the wheel 9 at the drive side and the boss member 16 for the wheel 15 opposite the drive side have fitting diameters D3 and D4 thereof set such that D3 = D4. The present embodiment allows for effects of the fourth embodiment, and additionally permits the wheel 9 at the drive side and the wheel 15 opposite the drive to be commonly used, affording to provide wheels of a single kind as consumable supplies for maintenance to be simplified in control, and to manufacture a single kind of wheel that enables a mass production with an effect of cost reduction in the manufacture.
While preferred embodiments of the present invention have been described using specific terms, such description is for illustrative purposes, and it is to be understood that changes and variations may be made without departing from scope of the following claims.








What is claimed is:
1- A driving apparatus for railway rolling stocks
comprising:
an axle;
a boss member fit on an end portion of the axle;
a wheel at a drive side fit on an outer circumference of
the boss member;
a wheel opposite the drive side fit on another end portion
of the axle;
a gear fit on the outer circumference of the boss member, in a position nearer to a central portion of the axle than the wheel at the drive side;
a main motor arranged in a space between the wheels, in parallel to the axle; and
a pinion fit on a shaft end of the main motor, the pinion meshing with the gear.
2- The driving apparatus for railway rolling stocks as
claimed in claim 1, wherein an outside diameter of a
wheel-fitting boss portion of the boss member for the wheel to
fit thereon is smaller than an outside diameter of a
gear-fitting boss portion of the boss member for the gear to
fit thereon.
3. The driving apparatus for railway rolling stocks as claimed in claim 2, wherein the wheel-fitting boss portion of the boss member is provided with a projection at an end thereof

nearer to the central portion of the axle, the gear is formed with a recess in a corresponding portion thereof to fit on the projection, and for the gear fit on the gear-fitting boss portion, the projection and the recess are concavo-convexly fit to each other, whereby concavo-convexly contacting surfaces thereof have positions thereof in an axial direction of the axle falling into a place in the axial direction as preset for the gear.
4. The driving apparatus for railway rolling stocks as claimed in claim 1, wherein an outside diameter of a wheel-fitting boss portion of the boss member for the wheel to fit thereon is equal to an outside diameter of a gear-fitting boss portion of the boss member for the gear to fit thereon, and the wheel-fitting boss portion and the gear-fitting boss portion are continued to each other without steps therebetween.
5. The driving apparatus for railway rolling stocks as claimed in claim 1, wherein an outside diameter of a wheel-fitting boss portion of the boss member for the wheel to fit thereon is equal to an outside diameter of a gear-fitting boss portion of the boss member for the gear to fit thereon, the wheel-fitting boss portion and the gear-fitting boss portion being continued to each other without steps therebetween, the gear-fitting boss portion of the boss member is provided with a projection at an end thereof nearer to the central' portion of the axle, the gear is formed with a recess in a corresponding portion thereof to fit on the projection.

and for the gear fit on the gear-fitting boss portion, the projection and the recess are concavo-convexly fit to each other, whereby concavo-convexly contacting surfaces thereof have positions thereof in an axial direction of the axle falling into a place in the axial direction as preset for the'gear¬ed The driving apparatus for railway rolling stocks as claimed in any one of claims 1 to 5, wherein the wheel opposite the drive side includes an axle fitting portion thereof as a divided structure of a combination of a wheel part and a boss part having a fitting diameter and a fit length thereof set identical to a fitting diameter and a fit length of a wheel-fitting boss portion of the boss member for the wheel- at the drive side.


Documents:


Patent Number 258826
Indian Patent Application Number 635/CHE/2008
PG Journal Number 07/2014
Publication Date 14-Feb-2014
Grant Date 10-Feb-2014
Date of Filing 14-Mar-2008
Name of Patentee KABUSHIKI KAISHA TOSHIBA
Applicant Address 1-1, SHIBAURA 1-CHOME MINATO-KU TOKYO 105-8001
Inventors:
# Inventor's Name Inventor's Address
1 KINOSHITA, TSUTOMU C/O INTELLECTUAL PROPERTY DIVISION TOSHIBA CORPORATION, 1-1, SHIBAURA 1-CHOME MINATO-KU, TOKYO 105-8001
PCT International Classification Number B 61 F 3/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 P2007-067614 2007-03-15 Japan