JP5144468B2 - Vehicle drive device - Google Patents

Description

  The present invention relates to a vehicle drive device that transmits a drive force of a rotating electrical machine to drive wheels. More specifically, the present invention relates to an in-wheel type vehicle drive device accommodated in a drive wheel.

  An in-wheel type vehicle drive device includes a motor (rotary electric machine) and a speed reducer in a drive wheel, and the rotation of the motor is torque-amplified by the speed reducer and transmitted to the drive wheel. . In this type of drive device, one of the two drive device cases (outer case) is provided with a wheel support portion, and the other (inner case) is provided with a motor stator attachment portion and a vehicle attachment portion (suspension device). ) Is provided. In other words, each of the drive device cases is subjected to a large load (Patent Document 1).

  Also, as another drive device, a case cover that closes the opening of the case by concentrating on the drive device case a portion that receives a large load, such as a vehicle attachment portion, a wheel support portion, a motor stator attachment portion, etc. There is also (patent document 2).

JP 2007-57015 A JP 2005-81871 A

  However, in the driving device described in Patent Document 1, a large load acts on each case, so that there is a possibility that the degree of adhesion of each case is reduced at the joint portion of the case and oil leakage occurs. For in-wheel type vehicle drive devices, it is desired to reduce the weight of the drive device in order to reduce the unsprung weight of the vehicle. However, in this drive device, a large load is applied to each case. Therefore, it has been difficult to reduce the weight of the case in terms of strength.

  On the other hand, in the driving device described in Patent Document 2, since no load acts on the case cover, the degree of close contact between the case and the cover does not decrease, so oil leakage is reliably prevented. be able to. In addition, since no load is applied to the case cover, the case cover can be reduced in weight and cost. As a result, the drive device can be reduced in weight and cost.

  However, in the drive device described in Patent Document 2, when the case cover is assembled, the rotor is not supported, and therefore the rotor is strongly eccentric due to the magnetic force of the permanent magnet provided in the rotor. In this state, if the rotation detection unit for detecting the rotation position of the rotor is to be assembled together with the cover, the rotation detection unit cannot be smoothly assembled to the rotor, and therefore the rotation detection unit may interfere with the rotor or the like and be damaged. There was a problem that it was very difficult to assemble the case cover.

  Accordingly, the present invention has been made to solve the above-described problems, and is an in-wheel type vehicle drive device capable of improving the assemblability of the case cover while achieving weight reduction and cost reduction. It is an issue to provide.

  The present invention, which has been made to solve the above-described problems, transmits the driving force of a rotating electrical machine including a stator wound with a coil and a rotor rotatably disposed on the inner periphery of the stator to driving wheels. The in-wheel type vehicle drive device includes a drive device case that houses the rotating electrical machine, and a case cover that closes an opening of the drive device case, and the drive device case is an output unit to the drive wheel. The case cover includes a rotor support portion that supports one end of the rotor, and a rotation detection portion that detects a rotational position of the rotor, and the rotor The support portion abuts against the end portion of the rotor prior to assembly of the rotation detection portion to the rotor, and the rotor is disposed concentrically with the stator while correcting the eccentricity of the rotor. , Characterized in that it comprises the sleeve portion guides smoothly formed assembly of the rotor of the rotation detecting unit.

  In this in-wheel type vehicle drive device, a drive device case that houses a rotating electrical machine is provided with a support portion that supports an output portion to a drive wheel, and an attachment portion to the vehicle. That is, a portion where a large load acts on the drive device case is concentrated. The case cover that closes the opening of the drive device case is merely provided with a rotor support portion that supports one end of the rotor and a rotation detection portion that detects the rotational position of the rotor. Hardly works. Accordingly, the case cover can be reduced in weight and cost. As a result, the weight and cost of the drive device can be reduced. In addition, since almost no load acts on the case cover, the degree of adhesion at the joint between the drive device case and the case cover does not decrease, so that oil leakage can be reliably prevented.

  Further, in this vehicle drive device, when the case cover is assembled to the drive device case, the rotation detecting portion is smoothly assembled without interfering with the rotor or the like while correcting the eccentricity of the rotor by the sleeve portion on which the guide is formed. be able to. That is, since the rotation detector can be assembled without causing interference with the rotor or the like, the assemblability of the case cover is improved.

  In the in-wheel type vehicle drive device according to the present invention, the guide has a tapered shape that gradually decreases in diameter from the tip, and the diameter of the tip is larger than the eccentric amount of the rotor. It is desirable.

  By making the shape of the guide in this way, the sleeve portion that can reliably correct the eccentricity of the rotor can be realized with a very simple configuration. This also contributes to cost reduction of the case cover.

  Further, in the in-wheel type vehicle drive device according to the present invention, either the joint surface of the drive device case with the case cover, or the joint surface of the case cover with the drive device case, A fitting projection that fits into a fitting hole formed on the other side is provided, and a tip end portion of the fitting projection is formed in the fitting hole prior to assembly of the rotation detection unit to the rotor. It is desirable to be fitted.

  In this vehicle drive device, a fitting projection is provided on the joint surface of the drive device case with the case cover, and a fitting hole for fitting the fitting projection is formed on the joint surface of the case cover with the drive device case. Alternatively, a fitting projection is provided on the joint surface of the case cover with the drive device case, and a fitting hole for fitting the fitting projection is formed on the joint surface of the drive device case with the case cover. . When the case cover is assembled to the drive device case, the tip of the fitting protrusion provided on the drive device case side or the case cover side is positioned on the case cover side prior to assembly of the rotation detection unit to the rotor. Or it fits in the fitting hole formed in the drive device case side.

  In this manner, the fitting cover and the fitting hole are fitted, whereby the case cover is accurately positioned with respect to the drive device case. Thereby, the rotor eccentric by the sleeve portion can be reliably arranged on the same core as the stator. For this reason, since the rotation detection unit can be more smoothly assembled to the rotor without causing interference with the rotor or the like, the assemblability of the case cover can be further improved.

  Here, since the guide is provided in the sleeve portion of the case cover, the axial length (axial length) of the driving device may be increased correspondingly. However, since an in-wheel type drive device is required to be compact, it is necessary to shorten the axial length as much as possible.

  Therefore, in the in-wheel type vehicle drive device according to the present invention, the rotor support portion may overlap the rotation detection portion and the coil end of the stator in the axial direction.

  By doing so, the rotor support portion and the rotation detection portion are positioned on the inner periphery side of the coil end of the stator. it can.

  In the in-wheel type vehicle drive device according to the present invention, the rotor includes a rotor core including a permanent magnet, and a rotor hub to which the rotor core is fixed. The flange portion of the rotor hub includes the sleeve portion. It is also preferable that a relief portion having a reduced thickness is formed so that the tip of the contact portion does not come into contact.

  By forming the relief portion in the flange portion of the rotor hub in this manner, it is possible to reliably suppress an increase in the axial length of the drive device due to the provision of the guide in the sleeve portion. In addition, since only the relief portion is thin, the center of the flange portion can secure the same thickness as the conventional one, so that a sufficient joint area with the rotor shaft can be secured and the necessary joint strength can be maintained. it can.

  According to the in-wheel type vehicle drive device of the present invention, as described above, it is possible to improve the assemblability of the case cover while reducing the weight and cost of the drive device case.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a most preferred embodiment that embodies an in-wheel type vehicle drive device of the present invention will be described in detail with reference to the drawings. In the following embodiments, a drive unit for an electric vehicle to which the present invention is applied will be described as an example.

  Therefore, the drive unit according to the present embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a schematic configuration of a drive unit for an electric vehicle according to an embodiment. FIG. 2 is a cross-sectional view showing a schematic configuration of a brake device in a conventional drive unit. FIG. 3 is an exploded perspective view showing a part of the brake device in the drive unit according to the embodiment.

  As shown in FIG. 1, the drive unit 10 is housed in a wheel rim 11 a of the drive wheel 11. The drive unit 10 includes a motor (rotary electric machine) 20, a planetary gear 40, and a brake device 60. The motor 20 and the planetary gear 40 are housed in the case 12, and the opening 12 a of the case 12 is closed by the case cover 13. A plurality of knock pins 50 for positioning the case cover 13 with respect to the case 12 are provided on the joint surface of the case cover 13 with the case 12. On the other hand, a pin hole 51 into which these knock pins 50 are fitted is formed on the joint surface of the case 12 with the case cover 13. The length of the knock pin 50 (the length protruding from the joint surface) is such that when the case cover 13 is attached to the case 12, the tip of the knock pin 50 is inserted into the pin hole 51 prior to assembly of the resolver 31 described later. It is set to fit. The case 12 is provided with an attachment portion 14 for the vehicle, and the case 12 is suspended from the vehicle via a suspension device assembled to the attachment portion 14.

  An output shaft 15 is rotatably supported by a boss portion 12b of the case 12 via a bearing 16 and protrudes out of the case. A hub 17 for fixing the wheel rim 11 a is spline-engaged with the output shaft 15 and is secured and fixed by a nut 18.

  The motor 20 is a brushless DC motor, and includes a stator 21 fixed to the case 12 and a rotor 25 that is rotatably supported with a small gap (air gap) from the stator 21. The stator 21 is composed of a large number of laminated steel plates, and includes a stator core 22 in which a large number of teeth are radially formed from an annular portion disposed on the inner diameter side, and a three-phase coil 23 wound around the teeth. Have. The stator 21 is fixed to the case 12.

  On the other hand, the rotor 25 is composed of a large number of laminated steel plates, and a rotor core 26 having permanent magnets such as rare earth magnets embedded therein at predetermined intervals in the circumferential direction and extending in the axial direction, and the rotor core 26 fixed to the outer circumferential surface. The rotor hub 27 is supported, and the rotor shaft 28 is fixed to the center of the rotor hub 27. The rotor hub 27 has a flange portion 27 a extending in the inner diameter direction at the inner end thereof, and the flange portion 27 a is fixed to the rotor shaft 28. The rotor shaft 28 is supported by the output shaft 15 via a bearing 29 at one end, and supported by the rotor support 19 of the case cover 13 via a bearing 30 at the other end.

  The rotor support portion 19 is provided on the inner side of the case cover, and includes a sleeve portion 13a in which a guide 13b having a tapered shape that gradually decreases in diameter from the front end side is formed at the front end portion. When the case cover 13 is attached to the case 12, the guide 13 b abuts against the end of the rotor 25 (more precisely, the bearing 30) prior to assembly of the resolver 31 described later, and corrects the eccentricity of the rotor 25. Is. The maximum diameter (the diameter of the tip portion) of the guide 13b is set larger than the eccentric amount of the rotor 25 (rotor shaft 28). Further, an annular relief portion 27 c is formed in the flange portion 27 a so that the tip of the guide 13 b does not contact the flange portion 27 a of the rotor hub 27. The escape portion 27c is formed inside the sleeve portion 27b, and the thickness thereof is thinner than the flange portion 27a located inside the sleeve portion 27b. Thereby, since the center of the flange part 27a has the same thickness as the conventional one, a sufficient area for joining with the rotor shaft 28 can be secured and the necessary joining strength is maintained.

  A resolver 31 for detecting the rotation position (rotation angle) of the rotor 25 is provided at the end of the rotor 25 on the case cover 13 side. The resolver 31 includes a rotor (excitation coil) 31a and a stator (detection coil) 31b. The rotor 31a is attached to the outer periphery of a sleeve portion 27b formed in the flange portion 27a, and the stator 31b is a case cover. 13 is attached. In the present embodiment, the resolver 31 is configured by assembling the case cover 13 to the case 12 so that the stator 31b is disposed on the outer periphery of the rotor 31a.

  Such a motor 20 is electrically connected to a controller and a battery in the vehicle body, and outputs a rotational force as a motor and also functions as a regenerative brake. The motor 20 is not limited to a brushless DC motor, and may be another synchronous or induction AC motor, or a DC motor.

  In the planetary gear 40, the sun gear S serves as an input element, the carrier CR serves as an output element, and the ring gear R serves as a fixed (reaction) element, thereby constituting a reduction gear. That is, the sun gear S is formed integrally with the rotor shaft 28, the carrier CR is formed integrally with the output shaft 15, and the ring gear R is fixed to the case 12.

  Specifically, the carrier CR includes a carrier body 41 that is bulged and integrally formed at one end of the output shaft 15, and a carrier cover 42 that is integrally fixed to the carrier body 41. Two pinion shafts 43 are disposed over the main body 41 and the cover 42, and the pinions P are rotatably supported by the pinion shafts 43 via needle bearings. A ring-shaped member 46 having spline teeth 45 on the outer peripheral surface is fixed to the inner surface of the case 12 by bolts 47. The ring gear R is fixed to the case 12 integrally by engaging the spline teeth 45 of the ring-shaped member 46 with the stepped portion of the teeth and retaining the ring gear R by the snap ring 48.

  The brake device 60 includes a brake rotor 61 fixed to the hub 17 and a brake caliper 62 attached to the case 12 so that the outer peripheral end of the brake rotor 61 passes inside. The brake caliper 62 is disposed on the outer periphery of the case 12 and includes a brake piston 63 and brake pads 64 and 65. The brake piston 63 is accommodated in a piston case 66 that includes a part of the case 12. That is, the piston case 66 is integrated with the case 12. Thereby, in the drive unit 10, the radial dimension is reduced as compared with the case where the piston case 166 and the case (drive device case) 112 have separate structures, like the brake device 160 in the conventional drive unit shown in FIG. ing.

  In such a brake device 60, the brake piston 63 moves forward (moves to the left in FIG. 1) in the piston case 66 by rotating the brake piston 63. In the present embodiment, the brake piston 63 is rotated by a motor. When the brake piston 63 moves forward, the brake pad 64 is pushed toward the brake rotor 61 by the brake piston 63. In response to this, the brake pad 65 moves to the brake rotor 61 side. As a result, the brake rotor 61 is sandwiched between the brake pads 64 and 65 so that the drive wheel 11 is braked.

  In the brake device 60, as shown in FIG. 3, a tension spring 67 is used as a return spring for returning the brake piston 63 to its original position, and this is disposed between the case 12 and the brake rotor 61. ing. As a result, the brake device 60 can be arranged further radially inward as compared with the case where the torsion spring 167 is used as the return spring as in the brake device 160 in the conventional drive unit shown in FIG. The radial dimension can be further reduced.

  Next, an assembly procedure of the drive unit 10 having the above configuration will be described with reference to FIGS. FIG. 4 is a diagram showing a state in the middle of assembling the drive unit for an electric vehicle according to the embodiment, and shows a state before the case cover is attached. FIG. 5 is a diagram showing a state in the middle of assembling the drive unit for an electric vehicle according to the embodiment, and shows a state in which the case cover is attached to the case.

  To assemble the drive unit 10, as shown in FIG. 4, the motor 12, the planetary gear 40, and the like are housed in the case 12, and the case 12 is attached to the driving wheel 11 and the brake device 60 on the outer periphery of the case 12. Attach to the vehicle. In this state, one end of the rotor 25 provided in the motor 20 is not supported. For this reason, the rotor 25 is strongly decentered by the magnetic force of the permanent magnet provided in the rotor core 26.

Here, when the case cover 13 to which the stator 31b of the resolver 31 is fixed is to be assembled to the case 12, the rotor 25 is eccentric, so that the stator 31b of the resolver 31 is smoothly placed on the outer periphery of the rotor 31a. It cannot be inserted (assembled), and the assembly of the case cover 13 may be very difficult.
However, in the present embodiment, the rotor support portion 19 of the case cover 13 has a sleeve portion 13a in which a tapered guide 13b is formed. The maximum diameter of the guide 13b is set larger than the eccentric amount of the rotor 25. Accordingly, as shown in FIG. 5, when the case cover 13 is assembled to the case 12, the sleeve portion 13a causes the eccentricity of the rotor 25 before the stator 31b of the resolver 31 is assembled to the outer periphery of the rotor 31a. The rotor 25 is arranged concentrically with the stator 21 after being reliably corrected.

  At this time, the knock pin 50 provided in the case cover 13 starts to be fitted into the pin hole 51 formed in the case 12. Thereby, positioning with respect to case 12 of case cover 13 is performed with sufficient accuracy. From this state, when the case cover 13 is pushed into the case 12 and the case cover 13 is joined to the case 12, the drive unit 10 shown in FIG. 1 is completed. At this time, simultaneously with the assembly of the case cover 13, the stator 31b of the resolver 31 is assembled to the outer periphery of the rotor 31a. When the resolver 31 is assembled, since the eccentricity of the rotor 25 is corrected, the stator 31b of the resolver 31 does not interfere with the rotor 25 and the like. Thus, in the drive unit 10, the assemblability of the case cover 13 is very good.

  In the drive unit 10 assembled in this way, when a current flows through the coil 23 of the stator 21, the rotor 25 rotates and the motor 20 outputs a predetermined torque. Then, the output torque of the motor 20 is transmitted to the planetary gear 40 via the rotor shaft 28. The planetary gear 40 receives the output torque received from the rotor shaft 28 via the sun gear S, and switches the output torque stepwise by the pinion gear P to output it to the carrier CR. As a result, the carrier CR and the hub 17 are rotated at a predetermined rotational speed, and the drive wheel 11 is driven.

When the vehicle travels, loads from the drive wheels 11 and the vehicle act on the drive unit 10, but these loads all act on the case 12 and do not act on the case cover 13. For this reason, the case cover 13 is not required to be as strong as the case 12. Accordingly, the case cover 13 can be reduced in weight and cost. Thereby, weight reduction and cost reduction of the drive unit 10 can be achieved.
In addition, since almost no load is applied to the case cover 13, the degree of close contact between the joint surfaces of the case 12 and the case cover 13 does not decrease, so that oil leakage can be reliably prevented.

  Here, the in-wheel type drive unit is required to be compact. However, in the drive unit 10, the guide 13 b is provided in the sleeve portion 13 a of the case cover 13, so that the axial length of the drive unit 10 is increased accordingly. There is a possibility that the length (axial length) becomes long.

  However, in the drive unit 10, as shown in FIG. 1, the rotor support portion 19 of the case cover 13 that supports the rotor 25 has a resolver 31 and a coil end of the stator 21 (a portion where the coil 23 projects from the stator core 22) and a shaft. Overlapping in the direction. Further, the flange portion 27 a of the rotor hub 27 is provided with a relief portion 27 c of the guide 13 b. For these reasons, the drive unit 10 is provided with the guide 13b so that the axial length is not increased.

  As described above in detail, according to the drive unit 10 according to the present embodiment, the rotor cover 19 that supports one end of the rotor 25 is provided in the case cover 13. The rotor support portion 19 is provided with a sleeve portion 13a in which a tapered guide 13b is formed. Thereby, when the case cover 13 is assembled to the case 12, the resolver 31 can be assembled while correcting the eccentricity of the rotor 25 by the guide 13b, so that the assemblability of the case cover 13 is improved.

  Further, in the drive unit 10, since the boss portion 12 b that supports the output shaft 15 and the attachment portion 14 to the vehicle are provided in the case 12, a large load acts only on the case 12, and the case cover 13 has almost no load. Does not work. For this reason, the case cover 13 can be reduced in weight and cost, and as a result, the drive unit 10 can be reduced in weight and cost. In addition, since almost no load acts on the case cover 13, the degree of adhesion between the case 12 and the case cover 13 does not decrease, so that oil leakage can be reliably prevented.

  It should be noted that the above-described embodiment is merely an example and does not limit the present invention in any way, and various improvements and modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the knock pin 50 is provided on the case cover 13, but the knock pin 50 may be provided on the case 12. In this case, the pin hole 51 may be formed on the case cover 13 side.

It is sectional drawing which shows schematic structure of the drive unit for electric vehicles which concerns on embodiment. It is sectional drawing which shows schematic structure of the brake device in the conventional drive unit. It is a disassembled perspective view which shows a part of brake device in the drive unit which concerns on embodiment. It is a figure which shows the mode in the middle of the assembly of the drive unit for electric vehicles which concerns on embodiment, and shows the state before attaching a case cover. It is a figure which shows the mode in the middle of the assembly of the drive unit for electric vehicles which concerns on embodiment, and shows the state which has attached the case cover to the case.

Explanation of symbols

10 Drive unit (vehicle drive unit)
11 Drive Wheel 12 Case 12a Opening 12b Boss (Output Shaft Support)
13 Case cover 13a Sleeve portion 13b Guide 14 Mounting portion 15 Output shaft 19 Rotor support portion 20 Motor 21 Stator 25 Rotor 27 Rotor hub 27a Flange portion 27b Sleeve portion 27c Escape portion 28 Rotor shaft 31 Resolver 31a Rotor (excitation coil)
31b Stator (detection coil)
40 planetary gear 50 dowel pin (fitting protrusion)
51 pin hole (fitting hole)
60 Brake device

Claims (5)

In an in-wheel type vehicle drive device that transmits a driving force of a rotating electrical machine including a stator wound with a coil and a rotor disposed rotatably on the inner periphery of the stator to driving wheels.
A drive case for housing the rotating electrical machine;
A case cover for closing the opening of the drive device case;
The drive device case includes a support portion that supports an output portion to the drive wheel, and an attachment portion to the vehicle.
The case cover includes a rotor support portion that supports one end of the rotor, and a rotation detection portion that detects a rotation position of the rotor,
The rotor support portion abuts against an end portion of the rotor prior to assembly of the rotation detection portion to the rotor, and the rotor is arranged concentrically with the stator while correcting eccentricity of the rotor. A vehicle drive device comprising a sleeve portion on which a guide for smoothly assembling the rotation detection portion to the rotor is formed. The vehicle drive device according to claim 1,
The vehicle drive device according to claim 1, wherein the guide has a tapered shape that gradually decreases in diameter from the tip, and a diameter of the tip is larger than an eccentric amount of the rotor. In the vehicle drive device according to claim 1 or 2,
Either one of the joint surface of the drive device case with the case cover or the joint surface of the case cover with the drive device case is provided with a fitting protrusion that fits into a fitting hole formed in the other. And
The vehicle drive device according to claim 1, wherein a front end portion of the fitting protrusion is fitted into the fitting hole prior to assembly of the rotation detecting portion to the rotor. The vehicle drive device according to any one of claims 1 to 3,
The vehicle drive device according to claim 1, wherein the rotor support portion overlaps the rotation detection portion and a coil end of the stator in the axial direction. The vehicle drive device according to any one of claims 1 to 4,
The rotor includes a rotor core including a permanent magnet, and a rotor hub to which the rotor core is fixed,
The vehicle drive device according to claim 1, wherein an escape portion having a reduced thickness is formed on the flange portion of the rotor hub so that the tip of the sleeve portion does not contact.

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