JP2017158377A - Vehicle driving device with two motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle driving device with two motors in which loss of torque of a rolling bearing caused by induction thrust in a shaft direction is reduced in decelerators in two left and right rows.SOLUTION: The vehicle driving device with two motors comprises two electric motors 1L and 1R, and two decelerators 2L and 2R that decelerate individually driving force of the two electric motors 1L and 1R and transmits the force to left and right driving wheels. Gears of left and right gear rows constituting the decelerators 2L and 2R are formed of herical gears. Inboard sides of output gear shafts 25L and 25R are supported by rolling bearings 37a fitted into bearing fitting holes 35a constituted of through-holes provided at a partition wall 21 of a center casing 20a of a decelerator casing 20, and a thrust bearing 60 is provided between opposing shaft end surfaces of the left and right output gear shafts 25L and 25R.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a two-motor vehicle drive device including two electric motors and a reduction gear for independently driving left and right drive wheels.

  Patent Document 1 discloses a two-motor vehicle drive device including two electric motors and a speed reducer that drive left and right drive wheels independently of each other.

  This type of two-motor vehicle drive device eliminates the need for a differential gear that distributes the drive force of one electric motor to the left and right like a one-motor vehicle drive device that drives left and right drive wheels with one electric motor. Has the advantage.

  In addition, since the two-motor vehicle drive device is provided with an electric motor for driving independently for each of the left and right drive wheels, it is easy to vary the drive force of the left and right drive wheels. By generating a large amount of driving force on the wheels on the outside of the turn, it is easy to improve the running performance such as turning performance.

  As shown in FIG. 10, the conventional two-motor vehicle drive device disclosed in Patent Document 1 has two left and right electric motors 101 that individually drive left and right drive wheels, and two decelerations that reduce the rotation of the electric motor 101. The two speed reducers 102 are arranged in the center of the left and right electric motors 101.

  As shown in FIG. 10, the speed reducer 102 has an input gear shaft 123 having an input gear 123 a to which driving force is transmitted from the motor shaft 112, a large-diameter gear 124 a meshing with the input gear 123 a of the input gear shaft 123, and an output. An intermediate gear shaft 124 having a small-diameter gear 124b meshing with the gear 125a, and an output gear having an output gear, which is pulled out from the speed reducer casing 128 and transmits a driving force to the driving wheels via the constant velocity joint 126 and the intermediate shaft 127. A parallel shaft gear reducer including a shaft 125. The gear shafts of the left and right speed reducers 102 are arranged so as to overlap each other when viewed in a direction orthogonal to the gear shaft.

JP 2010-48379 A

  In order to reduce noise and vibration, helical gears are used for the gears 123, 124, and 125 constituting the parallel gear shaft reducer used in the two reduction gears 102. 123, 124, and 125 are supported by a reduction gear casing 128 so that both ends thereof are rotatable by rolling bearings.

  In the helical gear, since the gear teeth are inclined with respect to the shaft, an induced thrust is generated in the axial direction (thrust direction) when the driving force is transmitted. When both ends of the gear shaft are supported by the rolling bearing, the axially induced thrust is received by the rolling bearing. Due to this induced thrust, an axial load is applied to the rolling bearing and a torcross is generated, deteriorating the efficiency of the drive transmission system.

  In view of this, an object of the present invention is to provide a two-motor vehicle drive device that reduces the number of torcrosses of a rolling bearing due to axially induced thrust in two rows of left and right speed reducers.

  In order to solve the above-described problems, the present invention provides two electric motors for independently driving left and right driving wheels, and individually reduces the driving force of the two electric motors to the left and right driving wheels. Two reduction gears for transmission, and a motor casing of two electric motors is fixedly arranged on the left and right sides of a reduction gear casing that accommodates the two reduction gears in parallel on the left and right sides. The machine meshes with an input gear shaft having an input gear to which driving force is transmitted from the motor shaft, an output gear shaft having an output gear for transmitting driving force to the driving wheel, a large-diameter gear meshed with the input gear, and an output gear. An intermediate gear shaft having a small-diameter gear is arranged in parallel, and each gear of each gear shaft is a parallel shaft gear reducer formed by a helical gear. On both sides In the two-motor vehicle drive device having a three-piece structure of left and right side casings to be defined, the central casing is provided with a partition wall in the center, and the reduction gear casing has two storage chambers on the left and right by the partition wall. Each gear shaft of the speed reducer is supported by rolling bearings fitted in bearing fitting holes respectively provided in partition walls of the side casing and the central casing, and at least the inboard side of the output gear shaft Is supported by a rolling bearing fitted in a bearing fitting hole comprising a through hole provided in the partition wall of the central casing, and a thrust bearing is provided between the opposed shaft end faces of the left and right output gear shafts. And

  Further, the helical direction of the helical gears constituting the output gear of the output gear shaft is changed to the twist direction in which the axial direction induced thrust generated in the output gear is inward when the vehicle moves forward by the driving force from the electric motor. In this way, the twist direction of the helical gear teeth that form each gear of each gear shaft may be defined.

  Further, the helical gears that form the large-diameter gear that meshes with the input gear and the small-diameter gear that meshes with the output gear in the intermediate gear shaft may have the same twisting direction.

  As described above, according to the present invention, the axially induced thrust is canceled by receiving the axially induced thrust by the helical gears of the output gear shafts of the left and right wheels by the thrust bearing inserted between the gear shaft end portions. It is possible to suppress the axial load due to the induced thrust to the rolling bearing that supports the output gear shaft, and to reduce the torque cross of the output gear shaft.

It is a cross-sectional top view which shows embodiment of the 2 motor vehicle drive device which concerns on this invention. It is the end elevation which looked at the gear train of the embodiment of FIG. 1 from the direction of II-II line of FIG. It is sectional drawing to which the gear train part of embodiment of FIG. 1 was expanded. It is an expanded sectional view of the output gear shaft part of the embodiment of FIG. It is a cross-sectional top view of the left part of embodiment of the 2 motor vehicle drive device which concerns on this invention. It is a cross-sectional top view which shows other embodiment of the 2 motor vehicle drive device based on this invention. It is sectional drawing to which the gear train part of embodiment of FIG. 6 was expanded. It is a cross-sectional top view of the left side part of other embodiment of the 2 motor vehicle drive device which concerns on this invention. It is a schematic plan view which shows an example of the electric vehicle which uses the 2 motor vehicle drive device which concerns on this invention. It is a cross-sectional top view which shows an example of the conventional 2 motor vehicle drive device.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, the two-motor vehicle drive device A according to the present invention has a reduction gear casing 20 that accommodates two reduction gears 2L and 2R in parallel in the left and right directions. A structure in which motor casings 3L and 3R of the base electric motors 1L and 1R are fixedly arranged is adopted.

  The electric vehicle B shown in FIG. 9 is a rear wheel drive system, and independently drives the chassis 51, the front wheels 52 as steering wheels, the rear wheels 53 as drive wheels, and the left and right rear wheels 53, respectively. The two-motor vehicle drive device A is mounted on the chassis 51 at the center position of the left and right rear wheels 53 as drive wheels, and the drive force of the two-motor vehicle drive device A is constant speed. It is transmitted to the rear wheel 53 that is the left and right drive wheels via the joint 15 and the drive shaft 16. An inverter 9 that supplies electric power to the two-motor vehicle drive device A is installed at the center of the chassis 51.

  As a mounting form of the two-motor vehicle drive device A, a front wheel drive system and a four wheel drive system may be used in addition to the rear wheel drive system shown in FIG.

  The left and right electric motors 1L, 1R in the two-motor vehicle drive device A are housed in motor casings 3L, 3R, as shown in FIG.

  The motor casings 3L and 3R include cylindrical motor casing bodies 3aL and 3aR, outer walls 3bL and 3bR that close the outer surfaces of the motor casing bodies 3aL and 3aR, and reduction gears on the inner surfaces of the motor casing bodies 3aL and 3aR. It consists of inner walls 3cL and 3cR separated from 2L and 2R. The inner walls 3cL and 3cR of the motor casing bodies 3aL and 3aR are provided with openings for drawing out the motor shaft 12a.

  As shown in FIG. 1, the electric motors 1 </ b> L and 1 </ b> R are of a radial gap type in which a stator 11 is provided on the inner peripheral surface of the motor casing body 3 aL and 3 aR, and a rotor 12 is provided on the inner periphery of the stator 11. I am using something. The electric motors 1L and 1R may be axial gap types.

  The rotor 12 has a motor shaft 12a in the center, and the motor shaft 12a is drawn from the openings of the inner side walls 3cL and 3cR of the motor casing bodies 3aL and 3aR to the speed reducers 2L and 2R, respectively. A seal member 13 is provided between the openings of the inner side walls 3cL and 3cR of the motor casing bodies 3aL and 3aR and the motor shaft 12a.

  The motor shaft 12a is rotatably supported by the rolling bearings 14a and 14b on the inner side walls 3cL and 3cR and the outer side walls 3bL and 3bR of the motor casing bodies 3aL and 3aR (FIG. 1).

  As shown in FIG. 1, a speed reducer casing 20 that accommodates two speed reducers 2L and 2R provided in parallel in the left and right is a central casing 20a and left and right side casings 20bL fixed to both side surfaces of the central casing 20a. , 20bR three-piece structure. The left and right side casings 20bL and 20bR are fixed to the openings on both sides of the central casing 20a by a plurality of bolts (not shown).

  By fixing the side surface of the side casings 20bL and 20bR of the reduction gear casing 20 on the outboard side and the inner side walls 3cL and 3cR of the motor casing bodies 3aL and 3aR of the electric motors 1L and 1R with a plurality of bolts 29, the reduction gears are obtained. Two electric motors 1L and 1R are fixedly arranged on the left and right sides of the casing 20 (FIG. 1). The inboard side is the right side of FIG. 1, and the outboard side is the left side of FIG.

  As shown in FIG. 1, a partition wall 21 is provided at the center of the center casing 20a. The reduction gear casing 20 is divided into two left and right by the partition wall 21, and independent left and right accommodation chambers for accommodating the two reduction gears 2L and 2R are provided in parallel.

  As shown in FIG. 1, the speed reducers 2L and 2R are provided symmetrically and mesh with the input gear shafts 23L and 23R having the input gear 23a to which the driving force is transmitted from the motor shaft 12a. Intermediate gear shafts 24L and 24R having small diameter gears 24b meshing with the large diameter gear 24a and the output gear 25a, and the output gear 25a, are pulled out from the speed reducer casing 20 and are the constant velocity joint 15 and the drive shaft 16 (FIG. 9). This is a parallel shaft gear reducer provided with output gear shafts 25L, 25R that transmit the driving force to the drive wheels via the. The left and right input gear shafts 23L and 23R, intermediate gear shafts 24L and 24R, and output gear shafts 25L and 25R are arranged coaxially.

  Both ends of the input gear shafts 23L and 23R of the speed reducers 2L and 2R are fitted into bearing fitting holes 27a formed on both the left and right sides of the partition wall 21 of the central casing 20a and bearing fitting holes 27b formed in the side casings 20bL and 20bR. The rolling bearings 28a and 28b are rotatably supported.

  The end portions on the outboard side of the input gear shafts 23L and 23R are drawn outward from the opening portions 27c provided in the side casings 20bL and 20bR, and the openings 27c and the outer end portions of the input gear shafts 23L and 23R are connected to each other. A seal member 31 is provided between them to prevent leakage of the lubricating oil sealed in the speed reducers 2L and 2R and to prevent dust and muddy water from entering the speed reducers 2L and 2R from the outside.

  The input gear shafts 23L and 23R have a hollow structure, and the motor shaft 12a is inserted into the hollow input gear shafts 23L and 23R. The input gear shaft 23 and the motor shaft 12a are spline-coupled (including serration coupling).

  The intermediate gear shafts 24L and 24R are stepped gears having a large-diameter gear 24a meshing with the input gear 23a and a small-diameter gear 24b meshing with the output gear 25a on the outer peripheral surface. At both ends of the intermediate gear shafts 24L and 24R, rolling bearings 34a fitted into bearing fitting holes 32a formed on both surfaces of the partition wall 21 of the central casing 20a and bearing fitting holes 32b formed on the side casings 20bL and 20bR, 34b is supported.

  The output gear shafts 25L and 25R have a large-diameter output gear 25a, and are formed in bearing fitting holes 35a formed on both surfaces of the partition wall 21 of the central casing 20a and bearing fitting holes 35b formed on the side casings 20bL and 20bR. It is supported by the fitted rolling bearings 37a and 37b.

  Outboard side ends of the output gear shafts 25L and 25R are drawn out of the reduction gear casing 20 through openings formed in the side casings 20bL and 20bR, and are pulled out to the outboard side of the output gear shafts 25L and 25R. The outer ring member 15a of the constant velocity joint 15 is splined (including serration coupling) to the inner peripheral surface of the end.

  The constant velocity joint 15 coupled to the output gear shafts 25L and 25R is connected to the drive wheel 53 via the drive shaft 16 (see FIG. 9).

  A seal member 39 is provided between the end of the output gear shaft 25L, 25R on the outboard side and the opening 35c formed in the side casing 20bL, 20bR, and leakage of the lubricating oil sealed in the speed reducers 2L, 2R And prevents dust and muddy water from entering the reducers 2L and 2R from the outside.

  The gear shafts 23L, 23R, 24L, 24R, 25L, and 25R constituting the gear shafts 23L, 23R, 24L, 24R, 25L, and 25R constituting the parallel shaft gear reducers used for the two speed reducers 2L and 2R of the two-motor vehicle drive device A Is a helical gear, and the gear shafts 23L, 23R, 24L, 24R, 25L, and 25R are supported by the reduction gear casing 20 so that both ends thereof are rotatable by rolling bearings as described above.

  In the helical gear, since the gear teeth are inclined with respect to the shaft, an induced thrust (hereinafter referred to as thrust force) is generated in the axial direction (thrust direction) when the driving force is transmitted.

  The direction of the thrust force generated during forward drive by the helical gear in the two-motor vehicle drive device A according to the present invention is indicated by arrows in FIG.

  Here, FIG. 2 shows an end view seen from the direction of the line II-II in FIG. 1, and the rotation direction of the output gear shaft 25L is shown by an arrow. The front of the vehicle is the upper side of FIG. 2, and the output gear shaft 25L rotates clockwise.

  In the two-motor vehicle drive device A according to the present invention, as shown in FIG. 1, the torsional direction of the helical gear teeth constituting the output gear 25a of the output gear shafts 25L and 25R is changed to the thrust force ( Helical gears that form the gears 23a, 24a, 24b, 25a of the gear shafts 23L, 23R, 24L, 24R, 25L, 25R in the two speed reducers 2L, 2R so that f2) is inward Defines the twist direction of the teeth.

  The helical gear teeth of the gear trains of the reduction gears 2L and 2R are shown in FIG. 1 and FIG. 3 as the gear trains of the left reduction gear 2L and the right reduction gear 2R. The twist direction of the input gear 23a of the shaft 23L is right-handed, the twist direction of the large-diameter gear 24a of the intermediate gear shaft 24L is left-handed, the twist direction of the small-diameter gear 24b of the intermediate gear shaft 24L is left-handed, and the output of the output gear shaft 25L The twist direction of the gear 25a is right twist. The twist directions of the large diameter gear 24a and the small diameter gear 24b of the intermediate gear shaft 24L are both left-handed. In the input gear shaft 23R, the input gear 23a is twisted in the left direction, the intermediate gear shaft 24R in the large diameter gear 24a is twisted in the right direction, the small gear 24b in the intermediate gear shaft 24R is twisted in the right direction, and the output gear shaft 25R. The twist direction of the output gear 25a is left-handed. The twist directions of the large diameter gear 24a and the small diameter gear 24b of the intermediate gear shaft 24R are both right-handed.

Direction of thrust force generated during forward drive by the helical gears forming the gears 23a, 24a, 24b, 25a in the two-motor vehicle drive device A according to the present invention (
FIG. 1 shows f1 and f2).

  Since the intermediate gear shafts 24L and 24R have two gears, a large-diameter gear 24a that meshes with the input gear 23a of the input gear shafts 23L and 23R and a small-diameter gear 24b that meshes with the output gear 25a of the output gear shafts 25L and 25R. When the thrust forces generated in the two gears are in the same direction, the thrust direction force increases. Therefore, the thrust forces (f1, f2) generated during forward drive, which occupy most of the traveling direction, are opposite to each other (f1 inward, f2 Outward), the thrust force generated in the two gears is canceled out to reduce the thrust force applied to the intermediate gear shafts 24L, 24R.

  The direction of the thrust force (f2) applied to the intermediate gear shafts 24L and 24R is symmetrical between the right and left drive transmission systems in the left and right rows of reduction gears 2L and 2R, that is, both the left and right thrust forces are external. The torsion direction of the helical gear teeth is set so as to be oriented.

  The thrust force f2 generated during forward drive of the output gear 25a of the output gear shaft 25L, 25R, which is the final stage of the right drive transmission system and the left drive transmission system in the left and right rows of the reduction gears 2L, 2R, is inward. Is set.

  Since the output gear 25a of the output gear shafts 25L and 25R is the final stage gear of the drive transmission system, the load torque is large, and the inward thrust force generated during forward travel is also large.

  As described above, when the inward thrust force of the output gear shafts 25L and 25R is received by the rolling bearings 37a and 37a, an axial load is applied and a torcross is generated. Particularly, since the inward thrust force of the output gear shafts 25L and 25R is large, the torque cross here deteriorates the efficiency of the drive transmission system.

  Therefore, in this embodiment, the bearing fitting holes 35a formed on both surfaces of the partition wall 21 of the central casing 20a that supports the output gear shafts 25L and 25R are cylindrical through holes that communicate with the left and right accommodation chambers. Forming. The inboard side of the output gear shafts 25L and 25R is supported by rolling bearings 37a and 37a that are fitted into the bearing fitting holes 35a. A thrust bearing 60 is inserted between the opposed shaft end faces of the output gear shafts 25L and 25R, and a thrust bearing 60 is provided between the opposed shaft end faces of the output gear shafts 25L and 25R. The shafts 25L and 25R are connected via a thrust bearing 60. In this embodiment, a thrust ball bearing is used as the thrust bearing 60 to be inserted, but a thrust cylindrical roller bearing, a thrust tapered roller bearing, a thrust self-aligning roller bearing, or the like may be used.

  As shown in FIGS. 1 and 3, the output gear shafts 25L and 25R have shaft end portions protruding from the rolling bearing 37a. And the convex part 25L1 and 25R1 which are inserted in the internal-diameter part of the axial washer of the thrust bearing 60 are provided in this axial part. The convex portion 25L1 of the shaft end portion of the output gear shaft 25L is fitted into the inner diameter portion of one shaft washer of the thrust bearing 60, and the convex portion 25R1 of the shaft end portion of the output gear shaft 25R is fitted to the other shaft washer of the thrust bearing 60. The thrust bearing 60 is inserted between the opposed shaft end faces of the output gear shafts 25L and 25R, and the left and right output gear shafts 25L and 25R are connected via the thrust bearing 60.

  A thrust force, which is an inward induced thrust generated when the output gear 25a of the output gear shaft 25L, 25R is driven forward, is received by a thrust bearing 60 inserted between the gear shaft end portions of the output gear shaft 25L, 25R. Can be canceled. For this reason, since the axial load by induced thrust is not applied to the rolling bearings 37a and 37a that support the output gear shafts 25L and 25R, the torque cross of the output gear shafts 25L and 25R is reduced.

  The thrust bearing 60 is subjected to differential rotation of the left and right output gear shafts 25L and 25R when the vehicle is turning, but the torque cross here is small because it receives only the rotational speed difference between the inner and outer wheels. Further, at least when the vehicle is traveling straight, differential rotation does not occur, so that no torque cross occurs.

  As described above, the input gear shafts 23L and 23R, the intermediate gear shafts 24L and 24R, and the output gear shafts 25L and 25R that are the gear shafts of the speed reducers 2L and 2R are supported by the rolling bearings. Each rolling bearing is fitted in each bearing fitting hole provided in the speed reducer casing 20. The inner ring of the rolling bearing and each gear shaft 23L, 23R, 24L, 24R, 25L, 25R are fitted with tightness (tight fitting) so that the gear shaft can be rotated at the center of rotation. The outer ring and each bearing fitting hole are fitted with a clearance (loose fitting) to facilitate the assembling work of each gear shaft.

  Here, since the outer ring of each gear shaft support bearing is loosely fitted, it is necessary to reduce the backlash in the axial direction of the gear shaft from the viewpoint of reducing noise and vibration during driving and preventing wear of the bearing hole. is there. In order to properly maintain the axial bearing gap, the dimensions affecting the gap, such as the reduction gear casing 20, the gear shafts 23L, 23R, 24L, 24R, 25L, and 25R, are managed with high accuracy. Further, a spacer is inserted between the bearing fitting hole provided in the reducer casing 20 and the rolling bearing, and the clearance is adjusted for assembly.

  Since the bearing fitting hole 35a provided in the partition wall 21 of the central casing 20a is formed in a cylindrical through hole communicating with the left and right accommodation chambers, a spacer is inserted to keep the axial bearing gap properly. 65 does not need to be managed for each of the left and right output gear shafts 25L and 25R, and a single spacer 65 may be inserted into the shaft connected by the thrust bearing 60 as shown in FIG. For this reason, the number of the spacers 65 can be reduced.

  Further, since the bearing fitting hole 35a into which the output gear shafts 25L and 25R provided in the partition wall 21 of the central casing 20a are fitted can be formed by passing through a cylindrical hole, the machining can be easily performed.

  As described above, the intermediate gear shafts 24L and 24R have two gears, a large-diameter gear 24a that meshes with the input gear 23a of the input gear shafts 23L and 23R and a small-diameter gear 24b that meshes with the output gear 25a of the output gear shafts 25L and 25R. Therefore, the thrust forces (f1, f2) generated during forward drive, which occupies most of the traveling direction, are opposite to each other (f1 is inward and f2 is outward), and the thrust forces generated in the two gears are offset. Thus, the thrust force applied to the intermediate gear shafts 24L and 24R is reduced. In this embodiment, as shown in FIG. 5, the large-diameter gear 24a and the output small-diameter gear 24b have the same twist direction, the large-diameter gear 24a has a large twist angle, and the small-diameter gear 24b has a small twist angle. Then, the induced thrust in the axial direction can be offset or reduced by making the torsion angles of the large diameter gear 24a and the output small diameter gear 24b different so as to satisfy the following expression.

d1 / d2 = tanβ1 / tanβ2
Here, d1 is a reference circle diameter of the large diameter gear 24a, and d2 is a reference circle diameter of the small diameter gear 24b. β1 is a reference cylindrical helix angle of the large diameter gear 24a, and β2 is a reference cylindrical helix angle of the small diameter gear 24b.

  As described above, when there is no or small induced thrust in the axial direction, constant pressure preload with a small spring constant becomes possible, and the axial clearance can be canceled. For this reason, as described above, in the intermediate gear shafts 24L and 24R having no axially induced thrust, the torque cross of the rolling bearing 34a is eliminated, and the efficiency of the speed reducers 2L and 2R is improved.

  In addition, strict dimensional control of the reducer casing 20 and the intermediate gear shafts 24L and 24R is not required, and stable assembly in a short time is possible by inserting springs such as wave springs in place of a plurality of spacers to be prepared. Become.

  In addition, by eliminating or reducing the axial direction induced thrust, constant pressure preload by inserting a spring such as a wave spring becomes possible, and the shafts of the intermediate gear shafts 24L and 24R generated by fluctuations in rotational torque and changes in the rotational direction. Displacement is eliminated, sound vibration is reduced, and the life of the rolling bearing is improved.

  Further, the input gear shafts 23L and 23R mesh with the large gear 24a of the intermediate gear shafts 24L and 24R have a large twist angle, and the small gear 24b meshed with the output gear 25a of the output gear shafts 25L and 25R. Since the force in the thrust direction with respect to the torque increased in the final stage can be reduced, the burden on the rolling bearing 37a can be further reduced, which contributes to the improvement of efficiency and the improvement of the life of the rolling bearing 37a.

  In addition, the output gear shaft 25L, 25R, which generates an inward thrust force, has a three-piece structure including a central casing 20a and left and right side casings 20bL, 20bR fixed to both side surfaces of the central casing 20a. When incorporated in the reduction gear casing 20, since the large thrust force generated in the output gear 25a in the final stage of the left and right gear trains is inward, the left and right side casings 20bL and 20bR are separated from the central casing 20a. Not subject to direction force.

  The central casing 20a and the left and right side casings 20bL and 20bR are arranged so that the lubricating oil sealed in the speed reducer casing 20 does not leak and muddy water does not enter the speed reducer casing 20 from the outside. A sealing structure such as an O-ring or a liquid gasket is provided on the contact surface between the side casings 20bL and 20bR, and the central casing 20a and the left and right side casings 20bL and 20bR are fixed by fastening with bolts.

  The gears 23a, 24a, 24b, and 25a are formed so that the large thrust force generated in the output gear 25a at the final stage of the left and right gear trains is inward during forward drive. When the torsional direction is specified, the helical gear teeth twist direction and tooth surface during reverse travel (during reverse drive) by the driving force from the electric motor and forward travel with regenerative braking (forward coast) The thrust force generated in the output gear 25a is reversed outward from the direction of the force applied in the circumferential direction. However, the frequency of retreat is less than that of the advance, and the frequency of applying a large driving force while retreating is less. Time is less likely to be a problem even when going outwards. The forward coast is less frequent than the forward drive, and a mechanical braking device such as a disc brake is also activated. In this case, the outward thrust force generated by the gears is also reduced, which is unlikely to be a problem.

  Therefore, it is possible to effectively prevent leakage of the lubricating oil sealed in the reduction gear casing from the contact surface between the central casing 20a and the left and right side casings 20bL and 20bR and intrusion of muddy water from the outside.

  Next, another embodiment of the present invention will be described with reference to FIGS. In the embodiment shown in FIGS. 6 to 8, the input gear shafts 23L and 23R other than the bearing fitting holes 35a formed on both surfaces of the partition wall 21 of the central casing 20a that supports the output gear shafts 25L and 25R are provided. The bearing fitting holes 27a formed on both surfaces of the supporting central casing 20a and the bearing fitting holes 32a formed on both surfaces of the central casing 20a supporting the intermediate gear shafts 24L, 24R are also cylindrical in shape communicating with the left and right accommodation chambers. It is formed with through holes.

  The inboard sides of the input gear shafts 23L and 23R are supported by rolling bearings 28a and 28a that are fitted into the bearing fitting holes 27a. A thrust bearing 60 is inserted between the opposed shaft end faces of the input gear shafts 23L and 23R, and the thrust bearing 60 is provided between the opposed shaft end faces of the input gear shafts 23L and 23R. 25L and 25R are connected via a thrust bearing 60.

  The inboard side of the intermediate gear shafts 24L and 24R is supported by rolling bearings 34a and 34a that are fitted into the bearing fitting holes 32a. A thrust bearing 60 is inserted between the opposed shaft end surfaces of the intermediate gear shafts 24L and 24R, and the thrust bearing 60 is provided between the opposed shaft end surfaces of the intermediate gear shafts 24L and 24R. 25L and 25R are connected via a thrust bearing 60.

  As shown in FIGS. 6 to 8, the input gear shafts 23L and 23R have shaft end portions protruding from the rolling bearing 28a. And the convex part 23L1, 23R1 fitted in the internal diameter part of the axial washer of the thrust bearing 60 is provided in this axial part. The convex portion 23L1 of the shaft end portion of the input gear shaft 23L is fitted into the inner diameter portion of one shaft washer of the thrust bearing 60, and the convex portion 23R1 of the shaft end portion of the input gear shaft 23R is fitted to the other shaft washer of the thrust bearing 60. The thrust bearing 60 is inserted between the shaft end portions of the input gear shafts 23L and 23R, and the left and right output gear shafts 25L and 25R are connected via the thrust bearing 60.

  Further, the intermediate gear shafts 24L, 24R have shaft end portions protruding from the rolling bearing 34a. And the convex part 24L1, 24R1 fitted in the internal diameter part of the axial washer of the thrust bearing 60 is provided in this axial part. The convex portion 24L1 of the shaft end portion of the intermediate gear shaft 24L is fitted into the inner diameter portion of one shaft washer of the thrust bearing 60, and the convex portion 24R1 of the shaft end portion of the intermediate gear shaft 24R is the other shaft washer of the thrust bearing 60. The thrust bearing 60 is inserted between the shaft end portions of the intermediate gear shafts 24L and 24R, and the left and right intermediate gear shafts 24L and 24R are connected via the thrust bearing 60.

  As shown in FIGS. 7 and 8, a bearing fitting hole 27a into which the input gear shafts 23L and 23R provided in the partition wall 21 of the central casing 20a are fitted, and a bearing fitting hole 32a into which the intermediate gear shafts 24L and 24R are fitted. Is formed in a cylindrical through hole communicating with the left and right accommodation chambers, so that the spacer 65 to be inserted in order to keep the axial bearing gap properly is the left and right input gear shafts 23L, 23R, the intermediate gear shaft 24L, It is not necessary to manage each of 24R, and one spacer 65 may be inserted into the shaft connected by the thrust bearing 60. For this reason, the number of the spacers 65 can be reduced. Since the bearing fitting hole 27a and the bearing fitting hole 32a can be formed by passing through a cylindrical hole, the machining can be easily performed.

  With respect to the torque cross between the input gear shafts 23L and 23R and the intermediate gear shafts 24L and 24R, each gear is set so that a large thrust force generated in the output gear 25a at the final stage of the left and right gear trains is inward during forward drive. 23a, 24a, 24b, 25a, when the helical direction of the helical gear teeth is defined, the input gear shafts 23L, 23R and the intermediate gear shafts 24L, 24R Therefore, it is effective when the thrust bearing 60 is sandwiched between the shaft end portions. However, the effect of the vehicle is limited because the frequency of deceleration and reverse of the vehicle is less than that of forward, and the frequency of applying a large driving force while moving backward is less.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. The scope of the present invention is claimed. The equivalent meanings recited in the claims, and all modifications within the scope.

1L, 1R: Electric motor 2L, 2R: Reducer 3L, 3R: Motor casing 3aL, 3aR: Motor casing body 3bL, 3bR: Outer wall 3cL, 3cR: Inner wall 4: Power line 5: Terminal box 9: Inverter 11: Stator 12: Rotor 12a: Motor shaft 13: Seal members 14a, 14b: Rolling bearing 15: Constant velocity joint 15a: Outer joint member 16: Intermediate shaft 20: Reduction gear casing 20a: Central casing 20bL, 20bR: Side casing 21: Partition Wall 23L, 23R: Input gear shaft 23a: Input gear 24L, 24R: Intermediate gear shaft 24a: Large diameter gear 24b: Small diameter gear 25L, 25R: Output gear shaft 25a: Output gear 27a, 27b: Bearing fitting hole 27c: Opening Portions 28a and 28b: Rolling bearing 29: Bolt 3 : Oil seals 32a, 32b: Bearing fitting holes 34a, 34b: Rolling bearings 35a, 35b: Bearing fitting holes 35c: Openings 37a, 37b: Rolling bearings 39: Oil seal 51: Chassis 52: Front wheel 53: Rear wheel 60 : Thrust bearing 65: Spacer A: Two-motor vehicle drive device B: Electric vehicle

Claims (3)

Two electric motors for independently driving the left and right driving wheels, and two reduction gears for individually decelerating and transmitting the driving forces of the two electric motors to the left and right driving wheels. The motor casings of the two electric motors are fixedly arranged on the left and right sides of the reduction gear casing that houses the basic reduction gears in parallel on the left and right sides, and the two reduction gears are input to which driving force is transmitted from the motor shaft. An input gear shaft having a gear, an output gear shaft having an output gear for transmitting a driving force to the drive wheel, a large gear meshing with the input gear, and an intermediate gear shaft having a small gear meshing with the output gear are arranged in parallel. Each gear shaft is a parallel shaft gear reducer formed by a helical gear, and the reducer casing is composed of a central casing and left and right side casings fixed to both side surfaces of the central casing. In 2 motor vehicle drive apparatus with structure;
The central casing is provided with a partition wall in the center, the speed reducer casing is divided into two storage chambers on the left and right by the partition wall, and each gear shaft of the speed reducer is connected to the side casing and the central casing. Supported by rolling bearings fitted in bearing fitting holes provided in the partition walls,
At least the inboard side of the output gear shaft is supported by a rolling bearing fitted in a bearing fitting hole made of a through hole provided in the partition wall of the central casing, and between the opposed shaft end surfaces of the left and right output gear shafts. A two-motor vehicle drive device characterized in that a thrust bearing is provided on the motor.   The helical gear teeth constituting the output gear of the output gear shaft are twisted so that the axially induced thrust generated in the output gear when the vehicle moves forward by the driving force from the electric motor is inward. 2. The two-motor vehicle drive device according to claim 1, wherein a helical twisting direction of a helical gear forming each gear of each gear shaft is defined.   The two-motor vehicle drive device according to claim 1, wherein the helical gears forming the large-diameter gear meshing with the input gear and the small-diameter gear meshing with the output gear in the intermediate gear shaft have the same twist direction.

Images