JP2001032888A - Drive unit for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To devise a thrust load working on a rotor to constantly work in one direction without increasing the thrust load large whichever of forwarding and backwarding directions rotation of an electric motor is in. SOLUTION: Rotation of a rotor 15 of an electric motor 5 is transmitted to a sun gear S1 through a rotor hub 19 and a shaft 20, decelerated by a first planetary gear 6b, decelerated further by a second planetary gear 6a from the sun gear S2, and output from an output shaft 10. The both sun gears S1, S2 are made of helical gears of helix angles in the opposite directions, and thrust loads work in a direction to push each other or in a direction to separate from each other in accordance with the rotating direction of the rotor. In the case of pushing each other, the thrust load of the sun gear S1 works on the shaft 20 through a step part 20a and works on the side of a car body against the thrust load of the sun gear S2. In the case of separating from each other, the thrust load of the sun gear S1 mainly works on the side of the car body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive unit for an electric vehicle having a two-stage planetary gear unit, and more particularly to a drive unit suitable for an in-wheel type electric vehicle drive unit.

[0002]

2. Description of the Related Art In-wheel type drive units are housed independently of each other in left and right drive wheels, and the drive units of the right and left drive wheels have different rotational driving directions of electric motors.

Conventionally, as an in-wheel type drive unit, a reduction gear comprising a two-stage planetary gear unit is housed in a case together with an electric motor, and the rotation of the motor is amplified by the two-stage reduction gear and the drive wheels are amplified. Something to communicate to has been devised.

[0004]

The same drive unit of the in-wheel type is installed on each of the left and right drive wheels, and therefore, the same helical gear of the planetary gear unit constituting the reduction gear has the same torsion angle direction. ing. As described above, the same drive unit is installed in the left and right driving wheels, and the driving rotation direction is different, so that the thrust load acting direction in the reduction gear is also different.

In particular, as described above, when two planetary gears arranged side by side in the axial direction are decelerated, if the torsional angles of the first and second stage planetary gears are the same, the two planetary gears have the same direction. The thrust load due to the planetary gears also increases, and as described above, since the same drive unit is used for the left and right drive vehicles, the difference between the thrust loads acting on the drive units on the left and right drive wheels increases.

[0006] Based on the difference in the thrust load direction between the left and right driving wheels, a sensor provided in a case for detecting the amount of axial displacement between the stator and the rotor and the rotational position of the rotor and a sensor detected by the sensor provided on the rotor hub are used. The amount of displacement in the axial direction from the drive unit differs between the left and right drive wheels, causing a difference in the electric motor performance of the drive unit between the left and right drive wheels and affecting the running performance of the electric vehicle.

In particular, on the side where the thrust load acts in the direction of the wheel, the rolling resistance increases due to the increase of the pressing force on the wheel bearing, and as a result, the running performance of the electric vehicle may be affected. is there.

On the other hand, on the side where the thrust load acts in the direction of the fuselage, the thrust bearing for supporting the thrust load has to be large, and the overall length of the drive unit becomes large. This causes a problem in the mountability of this type of drive unit, which is required.

When fixing a reaction force element of a planetary gear, for example, a ring gear, to a case of a drive unit,
In order to counter the large thrust load, it is necessary to increase the rigidity of the means for fixing the reaction force element,
This causes an increase in cost and weight.

Therefore, the present invention is configured such that the thrust load acting on the rotor always acts in one direction without increasing the thrust load, regardless of whether the rotation of the electric motor is in the forward or reverse direction. An object of the present invention is to provide a drive unit for an electric vehicle that solves the above-mentioned problems.

[0011]

According to a first aspect of the present invention, there is provided a planetary gear unit (6) in which an electric motor (5) and first and second planetary gears (6b) (6a) are juxtaposed in the axial direction. Wherein the rotation of the electric motor is transmitted to the output shaft (10) via the planetary gear unit composed of a helical gear, wherein the first and second planetary gears (6b) are provided. The thrust load acting on the rotor of the electric motor (15) is set to a predetermined direction regardless of whether the rotation of the rotor of the electric motor (15) is normal or reverse. Set to be
A drive unit for an electric vehicle is characterized in that:

According to a second aspect of the present invention, the rotor (1
5) is integrally coupled to the input element (S1) of the first planetary gear (6b), and transmits to the second planetary gear (6a) via reduction by the first planetary gear (6b). When the thrust load (Sb) acting on the second planetary gear is set to be larger than the thrust load (Sa) acting on the first planetary gear, and when the rotor (15) rotates in either the forward or reverse direction, The thrust load (Sa) of the first planetary gear (6b) acts on the rotor, and the rotor (15)
Rotates in the other direction, the difference (Sb-Sa) between the thrust loads acting on the first and second planetary gears acts on the rotor, so that the rotation of the rotor is either normal or reverse. The electric vehicle drive unit according to claim 1, wherein a thrust load in a predetermined one direction is applied.

According to a third aspect of the present invention, the first and second planetary gears (6b) and (6a) include an input element (S1) (S2) and an output element (CR1) (CR2), respectively.
And the fixed elements (R1) and (R2), and the fixed elements (R1) and (R2) are provided with thrust loads (Sa) and (S) in opposite directions regardless of whether the rotation of the rotor is normal or reverse.
3. The electric vehicle drive unit according to claim 1, wherein b) operates.

According to a fourth aspect of the present invention, the input element of the first planetary gear (6b) is a sun gear (S1), the input element of the second planetary gear (6a) is a sun gear (S2), and The sun gear is integrally connected to an output element (CR1) of the first planetary gear, and the rotor (15) is integrally connected to a rotatably supported shaft (20) to form a sun gear of the first planetary gear. (S1) is formed integrally with the shaft (20), and the sun gear (S2) of the second planetary gear is rotatably supported on the shaft (20), and a thrust is formed on a step (20a) formed on the shaft. When the rotor (15) rotates in one of forward and reverse directions by contacting via a bearing (26b), the two sun gears (S
1) The thrust loads (Sa) and (Sb) of (S2) act in directions away from each other, and the thrust load (Sa) of the sun gear (S1) of the first planetary gear exclusively passes through the shaft (20). When the rotor (15) rotates to the other side, the thrust loads (Sa) and (Sb) of the two sun gears (S1) and (S2) act so as to press each other. , The difference between the two thrust loads (| Sb−
3. The electric vehicle drive unit according to claim 2, wherein Sa |) acts.

According to a fifth aspect of the present invention, there is provided a rotor hub (19) for supporting a rotor (15) of the electric motor (5).
A detected portion (19b) is provided, and the detected portion is detected by a rotational position detecting means (21) mounted on the case (3) to detect the rotational position of the rotor, and the rotation of the rotor is reversed. In any case, the thrust load acting on the rotor hub (19) is reduced by the rotational position detecting means (21).
The drive unit for an electric vehicle according to any one of claims 1 to 4, wherein the drive unit is set to act toward the side.

According to a sixth aspect of the present invention, the drive unit (1) is an in-wheel type in which the drive unit (1) is disposed in a drive wheel (2) and the output shaft (10) is connected to the drive wheel. The same drive unit is arranged on wheels, and the rotors (15) of the electric motor rotate in opposite directions to each other on the left and right drive wheels.
6. The electric vehicle drive unit according to any one of the above items 1 to 5.

According to a seventh aspect of the present invention, when the vehicle is in a forward traveling state, in each of the drive units for the left and right drive wheels, the thrust load acting on the rotor (15) acts on the body side. 7. The drive unit for an electric vehicle according to claim 6, wherein the drive unit is set as follows.

[Operation] Based on the above configuration, the rotation of the rotor (15) of the electric motor (5) is reduced, for example, from the output element (CR1) via the input element (S1) of the first planetary gear (6b). The rotation is transmitted to the input element (S2) of the second planetary gear (6a) and to the drive wheels (2) via the output shaft (10).

At this time, the thrust load based on the helical gear acts on the rotor (15) in one predetermined direction regardless of whether the rotation of the rotor is in the forward or reverse direction. For example, referring to FIG. 3, the sun gear (S1), which is an input element of the first planetary gear, and the sun gear (S2), which is an input element of the second planetary gear, rotate in the same direction and have helical torsion in different directions. When the rotor (15) rotates, for example, counterclockwise, the first sun gear (S1) applies a thrust load (Sa) (Sb) in the left direction in the drawing and the second sun gear (S2) applies a thrust load (Sa) (Sb) in the right direction in the drawing. The second sun gear (S
2) The thrust load (Sb) of the first sun gear (S1)
(Sa <Sb).

At this time, for example, the first sun gear (S1)
Is formed on a shaft (20) integral with the rotor hub (19), and the thrust load (Sa) acting on the sun gear (S1) is directly applied to the rotor hub (19) and the rotor (15) via the shaft (20). The second sun gear (S2) is rotatable on the shaft (20) and has a thrust bearing (26b) on its step (20a).
, And the thrust load of the rotor hub (1) only in one predetermined direction is transmitted through the shaft (20).
9) and does not act on the rotor (15).

Therefore, the thrust load (Sb) acting on the second sun gear (S2) in the right direction in the drawing is:
It acts on the shaft (20) via the thrust bearing (26b) and the stepped portion (20a), and acts so as to press against the thrust load (Sa) of the first sun gear (S1). Difference between Sa) and (Sb) (| S
b-Sa |) acts on the rotor hub (19) and the rotor (15) in one predetermined direction via the shaft (20).

When the rotor (15) is rotated counterclockwise, for example, the first sun gear (S1) and the second sun gear (S1) are rotated.
The thrust loads (Sa) and (Sb) acting on 2) are in the opposite directions as described above, and both loads act in directions away from each other. At this time, the thrust load (Sb) of the second sun gear (S1) does not act on the shaft (20), and only the thrust load (Sa) of the first sun gear (S1) passes through the shaft (20). Acts on the rotor hub (19) and the rotor (15) in one predetermined direction.

The reference numerals in parentheses are for the purpose of comparison with the drawings, but are for convenience and do not limit the configuration of the present invention.

[0024]

According to the first aspect of the present invention, the thrust load acting on the rotor by the first and second planetary gears is in one predetermined direction regardless of whether the rotation of the electric motor is in the forward or reverse direction. Therefore, even if the electric motor rotates forward and backward, it is possible to accurately maintain the axial position accuracy of the rotor,
It is possible to obtain stable electric motor performance without changing the electric motor performance due to forward and reverse rotation of the electric motor, thereby improving the reliability and performance of the electric vehicle.

According to the second aspect of the present invention, the thrust load acting on the second planetary gear due to the torque increase due to the deceleration of the first planetary gear is made larger than the thrust load acting on the first planetary gear, and In one-way rotation, the thrust load of the first planetary gear acts exclusively on the rotor, and in the other direction of rotation of the electric motor, the difference between the thrust loads of both planetary gears acts on the rotor, regardless of whether the electric motor rotates normally or not. In addition to constantly applying a one-way thrust load to the rotor stably, it is possible to reliably maintain the axial positioning accuracy of the rotor, and reduce the maximum thrust load to reduce wheel bearing loss, By reducing the capacity of the thrust bearing, it is possible to reduce the size of the thrust bearing, and in particular to prevent the axial direction from becoming longer.

According to the third aspect of the present invention, the fixed elements of the first and second planetary gears always have their thrust loads acting in opposite directions regardless of the forward or reverse rotation of the electric motor. The thrust loads are reduced by canceling each other, so that the rigidity of the fixing means for fixing these fixing elements to the case or the like can be reduced or the number thereof can be reduced. For example, when the fixing element of the first and second planetary gears is a ring gear formed on a drum-shaped member, an annular disk (30) for fixing the drum-shaped portion (27) to the case (3a) and a retaining stopper. It is not necessary to increase the rigidity of the fixing snap ring (28) (that is, the thickness of the disk and the snap ring can be reduced);
Further, it is possible to reduce the number of bolts (31) for fixing the disk (30) to the case (3b), and together with these, it is possible to reduce the size, weight and cost in the axial direction. be able to.

According to the present invention, the sun gear of the first planetary gear is integrally formed on the shaft integrally connected to the rotor, and the sun gear of the second planetary gear is rotatably supported and the stepped portion thereof is provided. , Through a thrust bearing, depending on the direction of rotation of the rotor, a relatively large thrust load acts on the shaft against the smaller thrust load or does not act on the shaft. Therefore, the thrust load acting on the rotor can be always held in one predetermined direction with a highly reliable configuration.

According to the fifth aspect of the present invention, it is preferable that the electric motor, particularly the DC brushless motor, accurately detect the rotational position of the rotor in order to exhibit its performance. Instead, the rotor always faces the rotation position means to generate a thrust load, and the relative position between the rotation position detection means fixed to the case and the detected portion provided on the rotor hub is always maintained with high accuracy. In addition to maintaining the relative position between the motor and the rotor with high accuracy, the performance of the electric motor can always be maintained in a good state.

According to the sixth aspect of the present invention, the drive unit capable of maintaining high performance regardless of the forward / reverse rotation of the electric motor is applied as an in-wheel type in which the rotation of the electric motor is reversed between left and right drive wheels. By doing
While the same drive unit can be placed on the left and right drive wheels to reduce costs, the drive unit for the left and right drive wheels maintains almost the same high performance, and the performance of this type of in-wheel type electric vehicle Can be improved.

According to the seventh aspect of the present invention, when the vehicle is in the forward state, any of the drive units disposed on the left and right drive wheels causes the thrust load acting on the rotor to act on the body side. Therefore, the thrust load acting on the wheel bearing supporting the output shaft to the case can be reduced or eliminated, and the load on the wheel bearing can be reduced, and the running performance of the vehicle can be improved.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 are diagrams showing an in-wheel type drive unit suitable for use in an electric vehicle for a golf cart. As shown in FIG.
The drive unit 1 includes a wheel rim 2a of the drive wheel 2.
Is housed inside.

The drive unit 1 is divided into two cases 3
An electric motor (electric rotating means) 5 and a planetary gear unit 6 are accommodated in an integrated case 3 composed of a and 3b, and the integrated case 3 is suspended on a vehicle body 9 via a suspension device 7. . An output shaft 10 is rotatably supported by the outer case 3a via a wheel bearing 11 and protrudes out of the case. A hub 12 for fixing the wheel rim 2a is spline-engaged with the output shaft 10 and a nut is formed. It is stopped and fixed by 14.

As shown in detail in FIG. 2, the electric motor 5 is a brushless DC motor, and has a stator 13 fixed to the inner case 3b and a minute gap (air gap) G with the stator 13. And a rotor 15 rotatably supported. The electric motor (electric rotating means) 5 outputs a rotational force as a motor and also functions as a regenerative brake. Not only the brushless DC motor but also other synchronous or induction type AC motors, A DC motor may be used. Furthermore, the inner case 3b
An opening 17 for a multi-hole seal connector 16 is formed in the vehicle body, and electrically (electrically and electrically) communicates with a controller and a battery in the vehicle body. The rotor 1
5 has a rotor core 15a composed of a large number of laminated plates and a permanent magnet 15b such as a rare earth magnet which is embedded at predetermined intervals in the circumferential direction of the core and extends in the axial direction. And is fixed and supported on the outer peripheral surface of the. On the other hand, the stator 13 is formed of a number of laminated plates, and is wound around the magnetic pole teeth, and a magnetic pole part core 13a in which a number of magnetic pole teeth are formed radially outward from an annular portion arranged on the inner diameter side. Three-phase field coil 13b and an annular yoke core 13c integrally connected to the tip of the magnetic pole teeth
And the yoke core is connected to the inner case 3b.
It is fixed to the one.

The rotor hub 19 has a flange portion 19a extending in the inner diameter direction at an inner end thereof, and the flange portion 19a is fixed to the shaft 20. The shaft 20 is supported at both ends by the output shaft 10 and the inner case 3b via radial bearings 18 and 22, respectively. The rotor hub 19 has two flanges 1 projecting inward to form an annular groove.
9b and 19b are provided integrally, and a detecting portion 21a of a rotational position sensor (means) 21 is inserted between the flanges from outside the inner case 3b to detect the rotational position of the rotor. ing. The rotation position sensor 21 is preferably formed of a Hall element, but may be another rotation displacement sensor such as a photoelectric encoder such as a shaft encoder, a magnetic rotation sensor, or a resolver. The brushless DC motor 5
It is necessary to accurately control the alternating current applied to the stator while accurately determining the positional relationship between the rotor 15 and the stator 13.
Since the performance of the electric motor is greatly affected together with the positional accuracy of the stator and the rotor of the electric motor, it is necessary to sufficiently increase the axial positional accuracy between the sensor detector 21a and the rotor hub 19.

On the other hand, the planetary gear unit 6 is housed in the rotor hub 19 outside the flange portion 19a (left side in the drawing). The gear unit 6
Consists of two simple planetary gears 6a and 6b provided side by side in the axial direction.
2 is an input element, carriers CR1 and CR2 are output elements, and ring gears R1 and R2 are fixed (reactional) elements, forming a two-stage reduction gear. That is, the carrier CR1 of the inner (first) planetary gear 6b is connected to the sun gear S2 of the outer (second) planetary gear 6a, and the two ring gears R1, R2 are integrally formed. Also,
The inner sun gear S1 is formed integrally with the shaft 20 to constitute an input member, the outer sun gear S2 is rotatably supported on the shaft 20 via a needle bearing 23, and the outer carrier CR2 is connected to the output carrier CR2. It is formed integrally with the shaft 10. Each carrier CR
1 and CR2 rotatably support a plurality of pinion gears P1 and P2 via needle bearings 24 and 25, respectively, and the ring gears R1 and R2 and the sun gear S
1, S2 and the pinion gears P1 and P2 are formed of helical gears in a predetermined torsion angle direction, as described later.

[0036] Then, with the flange portion 19a, between the outer race of the radial ball bearing 22 for supporting one end of the shaft 20 to the inner casing boss portion 3b _1, and the outer (second) and the tip of the sun gear S2, the output shaft Thrust bearings 26a and 26c are interposed between the outer race of the radial ball bearing 18 supporting the other end of the shaft 20 and the shaft 20, respectively.
Step 20a and the integral inner (first) carrier CR1
A thrust bearing 26b with a race is interposed between the outer sun gear S2 and the outer sun gear S2. As a result, the thrust load acting on the outer sun gear S2 is reduced by the intermediate thrust bearing 26b and the step 2
0a and the rotor hub 19 via the shaft 20, but acts on the output shaft 10 via the thrust bearing 26c and on the case 3 via the wheel bearing 11 in the wheel direction (left direction in the drawing), 20
(Therefore, it does not act on the rotor hub 19).

Each of the ring gears R1 and R2 is formed of an internal gear having a different number of teeth formed on the inner peripheral surface of the drum-shaped member 27. A spline 27a is formed on the outer peripheral surface of the drum-shaped member 27. ing. Also, the outer case 3a
A flange 29 is integrally formed on the inner surface of the ring and projects inward in the axial direction in an annular manner. An annular disk 30 is fixed to the flange 29 by bolts 31. A spline 30a is formed on the inner peripheral surface of the disk 30. The spline 30a engages with the spline 27a of the drum-shaped member 27 and is prevented from being pulled out by a snap ring 28. , R2 are integrally (non-rotatably) supported by the case 3a.

An annular disk 3 for fixing the drum-shaped member 27
0 is tightly fixed to the tip of the annular flange 29 to form an annular space C between the disk 30, the outer case 3a and the annular flange 29, and a bottom portion thereof. ,
That is, a portion below the inner peripheral surface of the drum-shaped member 27 is an oil reservoir chamber A in which oil can be stored. Further, a narrow cut groove (small opening) 39 is formed at the lowermost portion of the annular flange portion 29, and the cut groove 39 is formed in the oil reservoir chamber A.
A discharge path is configured to squeeze and discharge a predetermined amount of oil stored in the tank. On the other hand, an oil sump B is formed in the lower part of the integral case 3, and the oil level of the oil sump B can be changed according to the amount of oil stored in the oil reservoir chamber A.

Then, as shown in FIG.
The planetary gear 6b) and the outer (second) planetary gear 6a are set such that the helical gears have opposite twist angles. Specifically, when viewed from the wheel side, the inner sun gear S1 is set to the left-hand screw direction and the outer sun gear S1 is set to the right-hand screw direction, and the inner pinion P1 and the inner ring gear are meshed with each other in the set torsion angle direction. A predetermined twist angle direction of R1, outer pinion P2, and outer ring gear R2 is set. The same drive unit 1 is used for the left drive wheel and the right drive wheel.

Next, the operation of the above embodiment will be described. Based on the driver's depression of the accelerator pedal, the rotor 15 of the electric motor 5 is driven by a signal from the controller.
Rotates. The rotation of the rotor 15 is transmitted to the inner sun gear S1 via the rotor hub 19 and the shaft 20,
Since the inner ring gear R1 is fixed, the inner carrier CR1 is reduced in speed and rotates in the same direction. Further, the inner carrier CR1 rotates the outer sun gear S2 integrally and the outer ring gear R2 is fixed,
Similarly, the outer carrier CR2 decelerates and rotates in the same direction,
It is transmitted to the output shaft 10. That is, the rotation of the rotor 15 is controlled by the inner planetary gear 6 b and the outer planetary gear 6.
The driving wheel 2 is decelerated at the two stages a and transmitted to the output shaft 10 to drive and drive the driving wheels 2.

Thus, even on a road with a lot of undulations such as a golf course, the electric motor 5 is controlled from the low speed rotation at the start by the large torque due to the two-stage deceleration and based on the accelerator pedal depression amount of the driver. The golf cart travels at a desired speed under the control of medium speed and high speed rotation. In addition, the electric motor 5 functions as a regenerative brake by the brake operation of the driver, and the cart stops by the action of a friction brake (not shown).

The drive of the drive unit 1 is performed by driving both left and right drive wheels, that is, one of the front wheels and the rear wheels (2
The electric motor 5 is driven to rotate in the opposite direction on the left and right drive wheels because the same drive unit 1 is used on the left and right sides. That is, when the vehicle is moved forward, the electric motor of the left drive unit rotates clockwise and the electric motor of the right drive unit rotates counterclockwise when viewed from the machine body side. 12 is rotated in the same direction.

As shown in FIG. 3, the left drive unit comprises a helical gear having a twist angle in the left-hand screw direction by right rotation of the inner (first) sun gear S1 based on right rotation of the rotor 15 of the electric motor. In the sun gear S1,
A tangential load Fa and a thrust load Sa indicated by arrows are generated. Further, a tangential load Fb and a thrust load Sb indicated by arrows are generated in the outer (second) sun gear S2 formed of a helical gear having a right-handed twist angle and rotating rightward through deceleration by the inner planetary gear 6b. At this time, the thrust loads Sa and Sb act in a direction in which the inner sun gear S1 is in the wheel direction (left direction in the drawing), while the outer sun gear S2 is in the fuselage direction (right direction in the drawing). And the thrust load S of the outer sun gear S2 whose torque has been increased through deceleration by the inner planetary gear 6b.
b is larger than the thrust load Sa of the inner sun gear S1 (Sa <Sb).

The thrust load Sb of the outer sun gear S2 acts on the shaft 20 in the machine direction via the thrust bearing 26b and the stepped portion 20a, and the inner sun gear S1 is formed directly on the shaft 20. The load Sa acts on the shaft 20 in the wheel direction. Therefore, a thrust load of [Sb-Sa] acts on the shaft 20, the rotor hub 19 integrated with the shaft, and the rotor 15 in the fuselage direction.

On the other hand, in the right drive unit, based on the left rotation of the rotor 15 of the electric motor 5, the inner sun gear S1 and the outer sun gear S2 also rotate left, and each sun gear has the same direction as that in FIG. A force (a vector of the same length in the opposite direction) is generated. That is, the thrust load Sa of the inner sun gear S1 is in the fuselage direction, while the thrust load Sb of the outer sun gear S2 is in the wheel direction, acting in a direction away from each other, and the thrust load S of the outer sun gear S1.
b is larger than that of the inner sun gear (Sa <S
b).

The thrust load Sa of the inner sun gear S1 directly acts on the shaft 20 (in the body direction).
Thrust load S of outer sun gear S2 acting in the wheel direction
b is the thrust bearing 26c, ball bearing 2
1 acts on the output shaft 10 via the outer race and on the case 3 via the wheel bearings 11,
It has no effect on zero. Thus, the shaft 20, and thus the integral rotor hub 19 and rotor 15, have |
Sa | thrust load acts in the fuselage direction.

As a result, in the drive units disposed on the left and right drive wheels, a thrust load in the body direction acts on the shaft 20, the rotor 15 and the rotor hub 19 when the vehicle advances. And shaft 2
_No. 0 is positioned with high accuracy on the inner case 3b (3b ₁ ) via the outer race of the thrust bearing 26a and the ball bearing 22 with respect to the thrust load in the fuselage direction, so that the same drive unit 1 is used. , A flange portion 19b serving as a detected portion provided on the rotor hub 19 in both the left and right drive units
And a rotational position detection sensor 2 installed in the inner case 3b.
The rotation accuracy of the rotor can be detected with high accuracy while maintaining the position accuracy with the first detection unit 21a in good condition. Similarly,
In both the left and right drive units, the position accuracy of the rotor 15 and the stator 13 installed in the inner case 3b in the axial direction can be maintained well, and the performance of the electric motor 5 can always be maintained at a predetermined high efficiency. Similarly, the rotor 1
As long as the axial position accuracy of No. 5 is satisfactorily maintained, the positional accuracy with the stator 13 supported by the inner case 3a is also always accurately maintained.

Further, the thrust loads Sa and Sb acting on the inner and outer sun gears S1 and S2 are superimposed regardless of whether the rotation of the electric motor 5 is normal or reverse, and do not act in the wheel direction. The thrust load acting on the output shaft 10 via the outer race 26c and the ball bearing 21 is also reduced, and the load on the wheel bearing 11 supporting the output shaft 10 to the case 3 is also reduced. That is, when the electric motor 5 is rotating clockwise,
The inner sun gear S1 and the outer sun gear S2 press against each other and act as a whole in the body direction, so that there is no thrust load acting on the output shaft 10 via the thrust bearing 26c. When the electric motor 5 is rotating counterclockwise, the thrust load Sa of the inner sun gear S1 acts on the machine body direction and does not act on the wheel direction, but the thrust load Sb of the outer sun gear S2 acts on the thrust bearing 26c and the like. Acts on the output shaft 10.

On the other hand, a thrust load caused by the helical gear also acts on the ring gears R1 and R2 fixed to the case as reaction force supporting members. The thrust loads of the ring gears R1 and R2 operate so as to cancel out the thrust loads of the sun gears S1 and S2, respectively, and the planetary gears 6a and 6b are balanced so that no thrust load is generated. Is set.

In the left drive unit 1, as shown in FIG. 3, a tangential load Fa and a thrust load Sa in the arrow direction are generated on the inner ring gear R1, and a tangential load Fa in the arrow direction is generated on the outer ring gear R2. Fb and thrust load Sa occur. The two thrust loads Sa, Sb move away from each other, that is, Sa of the inner ring gear R1 acts on the fuselage, and that of the outer ring gear R2 acts on the wheels, and the inner planetary gear 6 as the first-stage reduction gear.
The thrust load Sb of the outer ring gear R2 whose torque has been increased via b is larger than that of the inner ring gear R1 (Sa <Sb).

Since the two ring gears R1 and R2 are formed directly on the drum member 27, the thrust loads Sa and Sb acting on the respective ring gears in the opposite directions cancel each other out in the drum member 27. , And therefore the difference [Sb−
Sa] acts in the wheel direction. The thrust load of the drum-shaped member 27 in the wheel direction acts on the annular disk 30 via splines 27a and 30a, and is applied to the outer case 3a (29) to which the disk 30 is fixed by bolts 31. The thrust load S
Since a and Sb act in opposite directions to each other and are reduced to the difference therebetween, the force acting on the drum-shaped member 27, the disc 30, and the like is not large.

When a twist angle in a predetermined direction is formed in the splines 27a, 30a in which the drum-shaped member 27 and the disk 30 are engaged, the splines are generated by the tangential force (Fa + Fb) acting on the drum-shaped member 27. The thrust load based on the torsion angle cancels out the thrust load (Sb-Sa) by the helical ring gear, thereby accurately positioning the drum-shaped member 27 and reducing the force acting on the disk 30.

On the other hand, in the right drive unit 1,
Since the rotor 15 of the electric motor rotates counterclockwise, a load in the direction opposite to the arrow shown in FIG. 3 also acts on the ring gears R1 and R2. That is, a thrust load Sa in the wheel direction acts on the inner ring gear R1, and a thrust load Sb in the fuselage direction acts on the outer ring gear R2.
Acts in the direction of pushing each other and the outer thrust load S
Since b is larger than the inner Sa (Sa <Sb),
A thrust load of | Sb-Sa | acts on the drum-shaped member 27 in the machine body direction.

The thrust load of the drum-shaped member 27 in the machine direction is carried by the inner case 3a via the snap ring 28, the disc 30, and the bolt 31, but the thrust loads cancel each other. Since they are reduced together, they are not large, so that the snap ring 28 and the disc 30
It is not necessary to increase the rigidity of the disk 30 and it is not necessary to provide a large number of bolts 31 for fixing the disk 30 to the case.

Similarly, when a torsion angle is formed in the splines 27a, 30a in which the drum-shaped member 27 and the disk 30 are engaged, a tangential force acting on the drum-shaped member (the vector arrow indicates | Fa + Fb The thrust load based on the spline twist angle due to ||) is the thrust load due to the helical ring gear (the vector arrow
b-Sa |), and the drum-shaped member 27,
The force acting on the disk 30 and the snap ring 28 can be further reduced.

Therefore, as described above, the thrust loads are canceled each other, and the maximum thrust load of the entire apparatus can be reduced. As a result, a thrust bearing having a small load capacity can be used. Along with the fact that the snap ring 28 and the disc 30 can be thin and low in rigidity, the axial size of the drive unit can be reduced.

Next, an embodiment embodying the above description will be described with reference to the table of FIG. In the left drive unit, when the vehicle advances, the electric motor 5 rotates clockwise, a thrust load of 300 [kgf] in the machine direction occurs on the outer sun gear S2, and 100 [kgf] on the inner sun gear S1.
A thrust load in the wheel direction is generated. These two thrust loads act so as to press each other at the step portion 20a of the shaft 20, and the shaft 20, and therefore the rotor 15 and the rotor hub 19, have (300-100 = 200) [kgf].
Thrust load in the direction of the fuselage acts.

The outer ring gear R2 has a weight of 300 kg.
f], and a thrust load of 100 [kgf] in the machine direction is generated on the inner ring gear R1. These two thrust loads act on the integral drum-shaped member 27 as a (300-100 = 200) [kgf] thrust load in the wheel direction.

On the other hand, in the right drive unit, when the vehicle advances, the electric motor 5 rotates left and the outer sun gear S2
A thrust load of 300 [kgf] in the wheel direction occurs,
A thrust load of 100 [kgf] in the machine direction is generated on the inner sun gear S1. Since the thrust load (300 [kgf]) of the outer sun gear S1 does not act on the shaft 20, the thrust load (100 [kgf]) of the inner sun gear S1 is exclusively applied to the shaft 20, and thus to the rotor 15 and the rotor hub 19 integrated therewith. Acts in the fuselage direction.

The outer ring gear R2 has a weight of 300 kg.
f], and a thrust load in the wheel direction of 100 [kgf] is generated in the inner ring gear R1. Therefore, the drum-shaped member 27 in which each ring gear is integrally formed has (300-100). = 200) [k
gf] in the machine direction.

In the above description, the forward direction of the wheels has been described. However, when the vehicle travels in the reverse direction, the rotational direction of the electric motor is also reversed. Therefore, only the relationship between the left and right drive units is reversed. is there.

Next, another embodiment will be described with reference to FIGS. FIG. 5 shows that the helical gears of the first (inner) planetary gear and the second (outer) planetary gear, that is, the input elements of both planetary gears are in opposite directions of the torsional angle, and the two sun gears are the same as in the previous embodiment. FIG. 4 is a diagram showing two-stage planetary gear units (gear trains) in which the two rotate in the same direction.

The gear train 1 shown in FIG. 5 is shown by the skeleton of the previous embodiment (see FIGS. 1 to 4). When the rotation of the electric motor is input to the sun gear of the first planetary gear, In this embodiment, the ring gear is fixed, and the output is output from the carrier of the second planetary gear.In this embodiment, as described above, the input rotation (the rotation of the electric motor and the first sun gear) rotates forward (the right drive unit). In the case of the present skeleton centered on the left rotation, the left rotation described above is forward rotation), the first and second sun gears act so that the thrust loads are separated from each other, and thus the second sun gear The thrust load in the wheel direction is applied to the sensor portion of the shaft, and therefore the rotor and the rotor hub (1 in FIG. 2).
9b), a thrust force in the machine direction (toward the sensor unit) based on the first sun gear acts.

When the input rotation is reversed (corresponding to the right rotation in the left drive unit in the previous embodiment)
The thrust loads of the first and second sun gears act in a direction in which they press against each other, and the thrust load resulting from the difference acts on the sensor portion (rotor hub) in the machine direction.

The second gear train in FIG. 5 transmits the input rotation to the first sun gear, outputs the second ring gear, connects the first carrier to the second sun gear, and connects the first ring gear to the first ring gear. And the second carrier is fixed. The gear train is reduced by one stage by a first planetary gear and transmitted to a second sun gear, and the rotation of the second sun gear is output from a ring gear via a pinion gear whose rotation is prevented by being reduced from a ring gear. I do.

In this embodiment as well, when the input rotation is forward rotation (corresponding to the forward drive direction of the right drive unit), the thrust loads of the first and second sun gears act in directions away from each other, and the second sun gear The thrust load of the first sun gear acts on the sensor section (rotor hub) in the direction of the fuselage only on the sensor portion (rotor hub). When the input rotation is reverse (corresponding to the forward direction of the left drive unit), the thrust loads of the first and second sun gears act in a direction in which they push each other, and the sensor unit (rotor hub) applies both thrust loads. The difference acts in the direction of the fuselage (in the direction of the sensor unit).

The gear train 3 in FIG. 5 is input to the first sun gear and output from the second sun gear.
In addition, both carriers are integrally connected, and both ring gears are fixed. The rotation of the first sun gear is transmitted to the common carrier at a reduced speed and then transmitted to the second sun gear at an increased speed. At this time, the total gear ratio is set to be larger than 1, that is, set so as to decelerate.

Also in this embodiment, when the input rotation is forward rotation, the thrust loads of the first and second sun gears act in directions away from each other, and only the thrust load of the first sun gear is applied to the sensor unit. (Rotor hub) in the direction of the fuselage. When the input rotation is reverse, the thrust loads of the first and second sun gears act in a direction of pressing each other, and the difference between the two thrust loads acts on the sensor portion (rotor hub) in the machine direction.

The gear train 4 in FIG. 5 is input to the first sun gear and output from the second sun gear.
Both ring gears are connected and both carriers are fixed. The rotation of the first sun gear is reduced and transmitted to the common ring gear, and the rotation of the ring gear is further increased and transmitted to the second sun gear. At this time, the total gear ratio is set to be larger than 1 and the overall As slow down.

Also in this embodiment, when the input rotation is forward rotation, the thrust loads of the first and second sun gears act in directions away from each other, and only the thrust load of the first sun gear is applied to the sensor unit. (Rotor hub) in the direction of the fuselage. When the input rotation is reverse, the thrust loads of the first and second sun gears act so as to press each other, and the difference between the two thrust loads acts on the sensor portion (rotor hub) in the machine body direction.

FIG. 6 shows the helical gears of the first (inner) planetary gear and the second (outer) planetary gear, that is, the torsional angles of the input elements of both planetary gears are in the same direction, and these sun gears are in opposite directions. Rotate. It is a figure showing each planetary gear unit (gear train) of two steps.

The gear train 5 in FIG. 6 is input to the first sun gear, output from the second sun gear, and connects the first ring gear with the second sun gear.
The first carrier and the second ring gear are fixed. The rotation of the first sun gear is reduced and transmitted to the first carrier and the second ring gear, and the rotation of the ring gear is further increased and transmitted to the sun gear, where the total gear ratio is -1. Set smaller and decelerate as a whole.

Even in this embodiment, when the input rotation is forward rotation, the thrust loads of the first and second sun gears act in directions away from each other, and only the thrust load of the first sun gear is applied to the sensor unit. (Rotor hub) in the direction of the fuselage. When the input rotation is reverse, the thrust loads of the first and second sun gears act so as to press each other, and the difference between the two thrust loads acts on the sensor portion (rotor hub) in the machine body direction.

The gear train 6 in FIG. 6 inputs to the first sun gear and outputs from the second carrier, and connects the first ring gear and the second sun gear together with the first carrier and the second carrier. The second ring gear is fixed. The rotation of the first sun gear is reduced to the first
, And the rotation of the second sun gear is reduced and output from the second carrier.

Also in this embodiment, when the input rotation is forward rotation, the thrust loads of the first and second sun gears act in directions away from each other, and only the thrust load of the first sun gear is applied to the sensor unit. (Rotor hub) in the direction of the fuselage. When the input rotation is reverse, the thrust loads of the first and second sun gears act so as to press each other, and the difference between the two thrust loads acts on the sensor portion (rotor hub) in the machine body direction.

The gear train 7 in FIG. 6 inputs to the first sun gear, outputs from the second ring gear, connects the first ring gear to the second sun gear, and connects the first and second sun gears. The carrier is fixed. The rotation of the first sun gear is reduced and transmitted to the first ring gear and the second sun gear, and the rotation of the second sun gear is further reduced and output from the second ring gear.

Even in this embodiment, when the input rotation is forward rotation, the thrust loads of the first and second sun gears act in directions away from each other, and only the thrust load of the first sun gear is applied to the sensor unit. (Rotor hub) in the direction of the fuselage. When the input rotation is reverse, the thrust loads of the first and second sun gears act so as to press each other, and the difference between the two thrust loads acts on the sensor portion (rotor hub) in the machine body direction.

The gear train 8 in FIG. 6 inputs to the first sun gear, outputs from the second sun gear, and connects the first ring gear and the second carrier.
The first carrier and the second ring gear are fixed. The rotation of the first sun gear is reduced and transmitted to the first ring gear and the second carrier, and the rotation of the second carrier is increased in speed and output from the second sun gear. The total gear ratio is set to be smaller than -1, and the vehicle is decelerated as a whole.

Also in this embodiment, when the input rotation is forward rotation, the thrust loads of the first and second sun gears act in directions away from each other, and only the thrust load of the first sun gear is applied to the sensor unit. (Rotor hub) in the direction of the fuselage. When the input rotation is reverse, the thrust loads of the first and second sun gears act so as to press each other, and the difference between the two thrust loads acts on the sensor portion (rotor hub) in the machine body direction.

It should be noted that the present invention is not limited to the gear train shown in each of the above-described embodiments, but includes a two-stage planetary gear unit such as a gear train having a dual planetary gear, and a thrust load in the same direction regardless of whether the rotation of the electric motor is normal or reverse. Is similarly applicable to those in which

In the above-described embodiment, the in-wheel type drive unit in which the rotation of the electric motor is reversed in the left and right drive wheels has been described. However, the present invention is not limited to this. The same applies to other electric vehicle drive units such as a so-called de-freshing system in which the electric motor is directly transmitted to the left and right drive wheels, and a no-transmission system in which the rotation of the electric motor is simply decelerated and transmitted to the left and right drive wheels via a differential device. Applicable. in this case,
In the deflation method, the drive unit for the left and right drive wheels is the same as the in-wheel type described above, in which the rotation of the electric motor is reversed, but one drive unit of another method is installed in the vehicle body. In this case, the rotation of the electric motor is reversed when the vehicle is switched to forward or reverse, so that the above-described technical concept in which the thrust load becomes unidirectional can be applied. Further, the present invention can be similarly applied to a drive unit of a hybrid vehicle.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a drive wheel portion to which a drive unit according to the present invention is applied.

FIG. 2 is an enlarged sectional view showing the drive unit.

FIG. 3 is a schematic explanatory view showing a thrust load of two planetary gears.

FIG. 4 is a diagram showing a specific example of a direction and a magnitude of a thrust load.

FIG. 5 is a diagram showing an embodiment of each gear train (planetary gear unit) in which the helical torsional directions of two planetary gears are in opposite directions and the input elements of both planetary gears rotate in the same direction.

FIG. 6 is a diagram showing an embodiment of each gear train (planetary gear unit) in which the helical torsional directions of two planetary gears are the same and input elements of both planetary gears rotate in opposite directions.

[Explanation of symbols]

 Reference Signs List 1 drive unit 2 wheels 3 case 5 electric motor 6 planetary gear unit 6b first planetary gear S1 its sun gear (input element) CR1 its carrier (output element) R1 its ring gear (fixed element) 6a first planetary gear S2 its sun gear (input element) CR2 Its carrier (output element) R2 Its ring gear (fixed element) 13 Stator 15 Rotor 19 Rotor hub 19a Flange 19b Detected part (flange) 20 Shaft 20a Step 21 Rotational position detecting means (sensor) 26a, 26b, 26c Thrust Bearing Sa, Sb Thrust load

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ryota Horie 10 Takane, Fujii-cho, Anjo-shi, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Inventor Satoru Tanaka 2--19-12 Sotokanda, Chiyoda-ku, Tokyo No. Equos Research Co., Ltd. (72) Inventor Toshihisa Yoshida 60, Maruyama, Fujii-machi, Anjo-shi, Aichi F-term within AW Engineering Co., Ltd. 3D035 DA03 3J027 FA01 FA37 FB02 GA03 GB03 GC13 GC24 GC26 GD04 GD08 GD12 GE29

Claims (7)

[Claims] 1. An electric motor, and a planetary gear unit having first and second planetary gears juxtaposed in the axial direction.
A drive unit for an electric vehicle, which transmits rotation of an electric motor to an output shaft via the planetary gear unit formed of a helical gear, wherein a rotation direction of the first and second planetary gears and a torsion angle direction of the helical gear are provided. Wherein the thrust load acting on the rotor of the electric motor is set in a predetermined direction regardless of whether the rotation of the rotor is in the normal or reverse direction. 2. The second planetary gear acts on the second planetary gear by the rotor being integrally coupled to an input element of the first planetary gear and transmitting to the second planetary gear via deceleration by the first planetary gear. Is set to be larger than the thrust load acting on the first planetary gear, and when the rotor rotates in either forward or reverse, the thrust load of the first planetary gear acts exclusively on the rotor, and the rotor When the rotor rotates in the other direction, the difference between the thrust loads acting on the first and second planetary gears acts on the rotor. The drive unit for an electric vehicle according to claim 1, wherein a load is applied. 3. The first and second planetary gears include:
The thrust load in the direction opposite to each other is applied to each of the fixed elements, regardless of whether the rotation of the rotor is forward or reverse, each of which has an input element, an output element, and a fixed element. The drive unit for an electric vehicle as described in the above. 4. An input element of the first planetary gear is a sun gear, an input element of the second planetary gear is a sun gear, and the sun gear is integrally connected to an output element of the first planetary gear, and is rotatable. The first planetary gear sun gear is integrally formed with the shaft, the second planetary gear sun gear is rotatably supported by the shaft, and the shaft is supported by the shaft. When the rotor rotates in either forward or reverse direction, the thrust loads of the two sun gears act in a direction away from each other,
The thrust load of the sun gear of the first planetary gear exclusively acts on the rotor via the shaft, and when the rotor rotates to the other, the thrust loads of the two sun gears act so as to press each other, The drive unit for an electric vehicle according to claim 2, wherein a difference between the two thrust loads acts on the shaft and the rotor. 5. A detected portion is provided on a rotor hub supporting a rotor of the electric motor, and the detected portion is detected by a rotational position detecting means mounted on a case to detect a rotational position of the rotor. The electric vehicle according to any one of claims 1 to 4, wherein a thrust load acting on the rotor hub is set so as to act toward the rotation position detecting means, regardless of whether the rotation of the rotor hub is normal or reverse. Drive unit. 6. The in-wheel type wherein the drive unit is disposed in a drive wheel and the output shaft is connected to the drive wheel, wherein the same drive unit is disposed on left and right drive wheels,
The drive unit for an electric vehicle according to any one of claims 1 to 5, wherein the rotor of the electric motor rotates in opposite directions to each other at the left and right drive wheels. 7. The drive unit for each of the left and right drive wheels is set so that a thrust load acting on the rotor acts toward the fuselage when the vehicle is in a forward movement state. The drive unit for an electric vehicle according to the above.