JP2017025969A - Two-motor vehicle drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-motor vehicle drive unit composed of a gear row in a torsional direction which is intended by a layout while preventing an erroneous combination of left and right gears when forming a gear assembly by combining two gears to one shaft, in a left-and-right two-row reduction gear which is formed of helical gears.SOLUTION: Gears of gear shafts constituting reduction gears 2L, 2R are composed of parallel shaft gear reduction gears which are formed of helical gears, and in intermediate gear shafts 24L, 24R, a large-diameter gear 24a is fit to a shaft part 24s, and shapes of fitting parts between the large-diameter gear 24a and the shaft part 24s are made to differ from each other at the left and right reduction gears 2L, 2R.SELECTED DRAWING: Figure 2

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 and Patent Document 2 disclose a two-motor vehicle drive device including two electric motors and a reduction gear for independently driving left and right drive wheels.

  This type of two-motor vehicle drive device does not require a differential gear or the like 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 by 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. 8, the two-motor vehicle drive device includes left and right electric motors 101 that individually drive left and right drive wheels, and two reduction gears 102 that reduce the rotation of the electric motor 101, and the left and right electric motors. Two speed reducers 102 are arranged in the center of 101.

  As shown in FIG. 8, the speed reducer 102 has an input gear shaft 123 having an input gear 123a to which a driving force is transmitted from the motor shaft 112, a large-diameter gear 124a meshing with the input gear 123a 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.

Japanese Patent Laid-Open No. 11-243664 JP 2010-48379 A

  Helical gears are used for the gears of the gear shafts 123, 124, and 125 constituting the parallel gear shaft speed reducer used for the two speed reducers 102 of the two-motor vehicle drive device in consideration of noise reduction. There are many cases. The helical gear has a twist angle and generates an axial (thrust) force when rotating. For this reason, the speed reducer is designed in consideration of the twist direction of each gear so that the direction of this force can be balanced as a drive device. The bearing and housing that support the gear shaft are also designed in consideration of the thrust force.

  Further, when two gears are provided on one shaft, like the intermediate gear shaft in the above-described reduction gear, one gear is formed integrally with the shaft, and the other gear is fitted to the shaft portion to form 2 A gear assembly having two gears may be constructed.

  By the way, conventionally, the fitting portion of the gear and the shaft portion in the gear assembly is formed in the same shape in the left and right gears. For this reason, gears with different twist directions may be mistakenly incorporated. In this case, a gear train different from the intended twist direction is also assembled for the subsequent gears. In this way, when gears with a different direction of twisting from the design of the gear are combined, a load in the axial direction different from the direction intended by the design is applied to the drive unit, causing failure or damage to the bearing or housing. This will cause problems such as.

  Therefore, in the present invention, when a gear assembly is formed by combining two gears on one shaft in two right and left rows of reduction gears, the right and left gears are prevented from being mistaken, and the gear in the twist direction intended by the design is provided. A two-motor vehicle drive device comprising a row is provided.

  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. The two reduction gears transmit the driving force to the driving wheel via the input gear shaft having an input gear to which the driving force is transmitted from the motor shaft and the drive shaft. An output gear shaft having an output gear, a large-diameter gear meshing with the input gear, and an intermediate gear shaft having a small-diameter gear meshing with the output gear are arranged in parallel, and each gear of each gear shaft is formed by a helical gear. In the two-motor vehicle drive device including a parallel shaft gear reducer, the intermediate gear shaft is provided with at least one gear fitted to the shaft portion, and the shape of the fitting portion between the gear and the shaft portion is a left and right reduction gear. The machine has a different shape To.

  In addition, the gear and shaft portion of the intermediate gear shaft can be fitted by spline coupling and a press-fitting portion, and the diameter of the press-fitting portion can be made different by the left and right speed reducers.

In addition, the gear and shaft portion of the intermediate gear shaft can be fitted by spline coupling and press-fitting portions, and the spline specifications can be made different between the left and right speed reducers.

  Further, the fitting between the gear and the shaft portion in the intermediate gear shaft may be spline fitting, and the spline specifications may be different between the left and right speed reducers.

  The two speed reducers may be accommodated in a left and right parallel in a speed reducer casing, and the motor casings of the two electric motors may be fixedly arranged on the left and right with the speed reducer casing as the center.

  As described above, according to the present invention, since the shape of the fitting portion between the gear and the shaft portion is different between the left and right speed reducers, when the wrong gear is to be assembled, it cannot be assembled or incorporated. However, a gap is generated, and an error in combination can be recognized due to looseness, etc., and an error in the combination of the left and right speed reducers can be prevented.

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 top view of the crossing which expanded the reduction gear part of FIG. It is the end elevation which looked at the gear train of the embodiment of Drawing 1 from the direction of the III-III line of Drawing 1. It is a fragmentary sectional view which shows the intermediate gear shaft provided with the small diameter gear, and the large diameter gear fitted to this intermediate gear shaft. It is a fragmentary sectional view which shows the intermediate gear shaft provided with the small diameter gear of each right and left, and the large diameter gear fitted to this intermediate gear shaft. It is a fragmentary sectional view showing other examples of an intermediate gear shaft provided with a small diameter gear and a large diameter gear fitted to the intermediate gear shaft. 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 FIGS. 1 and 2, the two-motor vehicle drive device A according to the present invention has a reduction gear casing 20 that accommodates two reduction gears 2 </ b> L and 2 </ b> R in parallel on the left and right sides. A structure in which motor casings 3L and 3R of two electric motors 1L and 1R are fixedly arranged on the left and right is adopted.

  The electric vehicle B shown in FIG. 7 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. 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 intermediate 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 FIGS. 1 and 2, the speed reducer casing 20 that accommodates the two speed reducers 2L and 2R provided in parallel in the left and right is a central casing 20a and left and right sides fixed to both side surfaces of the central casing 20a. It has a three-piece structure of side casings 20bL and 20bR. 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).

  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 FIGS. 1 and 2, the speed reducers 2L and 2R are provided symmetrically and have input gear shafts 23L and 23R having an input gear 23a to which a driving force is transmitted from the motor shaft 12a, and the input gears. The intermediate gear shafts 24L and 24R having the large diameter gear 24a meshing with the output gear 23a and the small diameter gear 24b meshing with the output gear 25a, and the output gear 25a are pulled out from the speed reducer casing 20 and are connected to the constant velocity joint 15 and the intermediate shaft 16 ( FIG. 7) is a parallel shaft gear reducer provided with output gear shafts 25L, 25R that transmit a driving force to the drive wheels via FIG. 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 are inserted into bearing fitting holes 27a formed on both left and right sides of the partition wall 21 of the central casing 20a and bearing fitting holes 27b formed on the side casings 20bL and 20bR via rolling bearings 28a and 28b. And is supported rotatably.

  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. An oil seal 31 is provided between them to prevent leakage of lubricating oil sealed in the speed reducers 2L and 2R and intrusion of muddy water 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 shafts 23L and 23R and the motor shaft 12a are splined (including serrated coupling).

  The intermediate gear shafts 24L and 24R are stepped gear shafts 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.

  Both ends of the intermediate gear shafts 24L and 24R are respectively connected to 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 via rolling bearings 34a and 34b. It 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 rolling bearings 37a and 37b.

  Outboard side ends of the output gear shafts 25L and 25R are pulled out to the outside of the reduction gear casing 20 through openings 35c formed in the side casings 20bL and 20bR, and the output gear shafts 25L and 25R are pulled out to the outboard side. The outer joint member 15a of the constant velocity joint 15 is spline-coupled (including serration coupling) to the outer peripheral surface of the end portion.

  The constant velocity joint 15 coupled to the output gear shafts 25L and 25R is connected to the drive wheels via the intermediate shaft 16 (FIG. 7).

  An oil seal 39 is provided between the end of the output gear shafts 25L and 25R on the outboard side and the opening 35c formed in the side casings 20bL and 20bR, and leakage of the lubricating oil sealed in the speed reducers 2L and 2R In addition, entry of muddy water from the outside is prevented.

  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 each of the gear shafts 23L, 23R, 24L, 24R, 25L, 25R is supported on the reduction gear casing 20 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, a force is also generated in the axial direction (thrust direction) when the driving force is transmitted.

  Here, FIG. 3 shows an end view seen from the direction of line III-III 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 in FIG. 3, and the output gear shaft 25L rotates clockwise.

  In the two-motor vehicle drive device A according to the present invention, the gear shafts 23L, 23R, 24L, and the like in the two speed reducers 2L and 2R are arranged so that the direction of the force generated when the drive force is transmitted is balanced as the drive device. The helical directions of the helical gears forming the gears 23a, 24a, 24b, and 25a of 24R, 25L, and 25R are defined.

  The intermediate gear shafts 24L and 24R in the speed reducer have two gears, a large-diameter gear 24a that meshes with the input gear 23a and a small-diameter gear 24b that meshes with the output gear 25a. In the intermediate gear shafts 24L and 24R, the small-diameter gear 24b is formed integrally with the intermediate gear shafts 24L and 24R, and the large-diameter gear 24a is fitted to the shaft portion 24S of the intermediate gear shafts 24L and 24R. It consists of a gear assembly having two gears.

  In this embodiment, as shown in FIG. 4, a large-diameter gear 24a is provided with a female spline 24f and a press-fitting hole 24c for a press-fitting part 24d of the shaft part 24S. The intermediate gear shaft 24L (24R) is integrally formed with a small-diameter gear 24b, and is provided with a male spline 24e splined to the female spline 24f and a press-fitting portion 24d press-fitted into the press-fitting hole 24c. Yes.

  The male spline 24e of the shaft portion 24S is fitted into the female spline 24f of the large-diameter gear 24a, splined, and the press-fit portion 24d of the shaft portion 24S is press-fitted into the press-fitting hole 24c, so that the shaft portion 24S and the large-diameter gear 24a are fitted. To form a gear assembly having two gears.

  By the way, if the fitting part of the gear and shaft part in the gear assembly is formed in the same shape in the left and right gears, gears having different twist directions may be mistakenly incorporated. In this case, a gear train different from the intended twist direction is also assembled for the subsequent gears. In this way, when gears with a different direction of twisting from the design of the gear are combined, a load in the axial direction different from the direction intended by the design is applied to the drive unit, causing failure or damage to the bearing or housing. This will cause problems such as.

  Therefore, in this embodiment, as shown in FIG. 5, the shape of the fitting portion 24k formed by the press-fitting hole 24c of the gear 24a and the press-fitting portion 24d of the shaft portion 24S is made different between the left and right speed reducers. In this embodiment, the diameter size φA of the left press-fit hole 24c and the press-fit portion 24d is smaller than the diameter size φB of the right press-fit hole 24c and the press-fit portion 24d.

  In this way, by changing the diameter of the fitting portion 24k, when trying to assemble the wrong gear, it is impossible to assemble it, or even if it is assembled, a gap is generated and the combination is misunderstood. Can prevent mistakes in the combination of reducers.

  In the embodiment of FIG. 5, the spline specifications of the left and right speed reducers may be the same, or the spline specifications may be different on the left and right. Also, if the left and right reduction gears have different spline specifications, the right and left press-fit portions 24d and the press-fit holes 24c may have the same diameter, but if the wrong gear is to be assembled, Since they are different, spline fitting cannot be performed well, and an error in the combination of the left and right speed reducers can be prevented.

  In the embodiment shown in FIG. 6, the fitting between the gear 24a and the shaft portion 24S is a spline fitting. When the fitting between the gear 24a and the shaft portion 24S is a spline fitting, the spline specifications are made different between the left and right speed reducers. By changing the spline specifications, when trying to set the wrong gear, the spline specifications will be different, so the spline will not fit well and the right and left speed reducer combinations can be prevented. .

  In the above-described embodiment, the small-diameter gear 24b is formed integrally with the intermediate gear shafts 24L and 24R, but the small gear 24b is also formed by fitting with the shaft portions of the intermediate gear shafts 24L and 24R. Also good.

  In this case, the shape of the fitting portion between the small gear 24b and the shaft portion 24S is made different between the left and right speed reducers.

  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 24c: Press-fit hole 24d: Press-fit portion 24e: Male spline 24f: Female spline 24S: Shaft portion 24k: Fitting portion 25L, 25R: Output gear shaft 2 a: output gears 26L, 26R: bolts 27a, 27b: bearing fitting holes 27c: openings 28a, 28b: rolling bearings 29: bolts 31: oil seals 32a, 32b: bearing fitting holes 34a, 34b: rolling bearings 35a, 35b: Bearing fitting hole 35c: Openings 37a, 37b: Rolling bearing 39: Oil seal 51: Chassis 52: Front wheel 53: Rear wheel A: 2-motor vehicle drive device B: Electric vehicle

Claims (5)

  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 base reduction gear meshes with the input gear, 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 via the drive shaft, and the input gear. In a two-motor vehicle drive device comprising a parallel shaft gear reducer in which a large-diameter gear and an intermediate gear shaft having a small-diameter gear meshing with an output gear are arranged in parallel, and each gear of each gear shaft is formed by a helical gear The intermediate gear shaft is provided with at least one gear fitted to the shaft portion, and the shape of the fitting portion between the gear and the shaft portion is different between the left and right speed reducers. Vehicle drive device.   The gear of the intermediate gear shaft and the shaft part are formed by spline coupling and a press-fitting part, and the diameter dimension of the pressure part is formed in different dimensions by the left and right speed reducers. 2 motor vehicle drive.   3. The gear of the intermediate gear shaft and the shaft portion are formed by spline coupling and press-fitting portions, and the spline specifications are made different between the left and right speed reducers. 2 motor vehicle drive device.   2. The two-motor vehicle drive device according to claim 1, wherein the intermediate gear shaft is spline-fitted with a gear and a shaft portion, and the spline specifications are different between the left and right speed reducers.   The two reduction gears are housed in a left and right parallel in a reduction gear casing, and the motor casings of two electric motors are fixedly arranged on the left and right with the reduction gear casing as a center. 5. A two-motor vehicle drive device according to claim 4.

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