Drive unit

Abstract

To provide a driving device the size increase of which can be suppressed.SOLUTION: A driving device of the present invention is provided with a motor having a rotor arranged outside in a radial direction of a stator in a wheel of a vehicle wheel and comprises: a shaft arranged inside in the radial direction of the stator and coupled with the rotor via a rotary member; and a rotation sensor provided in the shaft to detect rotations of the shaft.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drive device. [Background technology]

[0002] Patent Document 1 discloses a vehicle drive device in which a so-called outer rotor type motor having a rotor arranged radially outside a stator is provided inside a wheel of a vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-100333 Summary of the Invention [Problem to be solved by the invention]

[0004] In an outer rotor type motor equipped in a vehicle drive device, if a rotation sensor is attached to the axial end faces of the rotor and stator, the axial length of the motor will increase, which will result in an increase in the size of the motor and, ultimately, the size of the vehicle drive device.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a drive device that can prevent an increase in size. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the drive device of the present invention is a drive device in which a motor having a rotor arranged radially outside a stator is installed within a wheel of a vehicle, and is characterized by comprising: a shaft arranged radially inside the stator and connected to the rotor via a rotating member; and a rotation sensor installed on the shaft for detecting rotation of the shaft. [Effects of the Invention]

[0007] The drive device of the present invention has the advantage of preventing the axial length of the motor from becoming too long and the size from becoming too large by providing a rotation sensor on a shaft arranged radially inside the stator. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram schematically illustrating an in-wheel motor unit according to the first embodiment. [Figure 2] FIG. 2 is a diagram schematically showing an in-wheel motor unit according to the second embodiment. [Figure 3] FIG. 3 is a diagram showing an example of how the sensor wiring and the brake wiring are routed. [Figure 4] FIG. 4 is a diagram schematically showing an in-wheel motor unit according to the third embodiment. [Figure 5] FIG. 5 is a diagram showing an example of how the sensor wiring and the brake wiring are taken out. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Embodiment 1) A first embodiment of a drive device according to the present invention will be described below, but the present invention is not limited to this embodiment.

[0010] FIG. 1 is a diagram schematically illustrating an in-wheel motor unit 1 according to a first embodiment. The in-wheel motor unit 1 is a drive device capable of driving and braking a wheel 10. The wheel 10 is a drive wheel including a wheel 11 and a tire 12, and is provided on both the left and right sides of a vehicle. The in-wheel motor unit 1 is provided inside the wheel 11. Note that FIG. 1 shows the right wheel of the wheels 10 provided on both the left and right sides, as viewed from the rear side of the vehicle. The direction parallel to the central axis of rotation of the wheel 10 is referred to as the axial direction.

[0011] The in-wheel motor unit 1 includes a motor 2, a reducer 3, a rotation sensor 4, a housing 5, a shaft 6, and an output member 7.

[0012] The motor 2 is an in-wheel motor that drives the wheels 10. The motor 2 is a three-phase AC motor, and is electrically connected to a power supply device mounted on the vehicle. During power running, the motor 2 generates power torque using power supplied from the power supply device to drive the wheels 10. During regeneration, the motor 2 is rotated by the rotational force of the wheels 10 to generate power, and supplies the generated power to the power supply device.

[0013] This motor 2 is an outer rotor type motor in which a rotor 21 is disposed radially outside a stator 22.

[0014] The rotor 21 is attached to the rotating member 23 and rotates integrally with the rotating member 23. The rotating member 23 is a cup-shaped member and has a cylindrical portion 23a and a disk portion 23b. The cylindrical portion 23a extends along the axial direction, and the rotor 21 is fixed to its inner circumferential surface. The disk portion 23b extends radially inward from one axial end of the cylindrical portion 23a, and its inner circumferential portion is connected to the shaft 6. For example, the inner circumferential portion of the disk portion 23b is spline-fitted with the outer circumferential portion of the shaft 6. Therefore, the rotor 21 is connected to the shaft 6 via the rotating member 23 and rotates integrally with the rotating member 23 and the shaft 6.

[0015] The shaft 6 is a rotating shaft member connected to the reducer 3. The rotor 21 is connected to the reducer 3 via the shaft 6. Therefore, the shaft 6 functions as the input shaft of the reducer 3 when transmitting the power of the motor 2 to the wheels 10. Because the motor 2 is connected to the wheels 10 via the reducer 3 so as to be able to transmit power, the power output from the motor 2 is transmitted to the wheels 10 via the reducer 3.

[0016] The stator 22 includes a stator core and a stator coil wound around the stator core. The stator coil is electrically connected to a power supply via motor wiring. The stator 22 is fixed to the housing 5.

[0017] The housing 5 is a non-rotating member that houses the motor 2 and the rotation sensor 4. The housing 5 has a cylindrical partition 51 that radially separates a space that houses the motor 2 from a space that houses the rotation sensor 4 that detects the rotation of the shaft 6.

[0018] The partition 51 is a cylindrical portion extending in the axial direction. Within the housing 5, the motor 2 is disposed on the outer circumferential side of the partition 51, and the rotation sensor 4 is disposed on the inner circumferential side of the partition 51. On the outer circumferential side of the partition 51, the stator 22 is fixed to the outer circumferential surface of the partition 51. On the inner circumferential side of the partition 51, a fixed portion 42 included in the rotation sensor 4 is fixed to the housing 5. The fixed portion 42 included in the rotation sensor 4 is a non-rotating member among the members that constitute the rotation sensor 4. Furthermore, on the inner circumferential side of the partition 51 within the housing 5, a rotating portion 41 included in the rotation sensor 4 is fixed to the shaft 6. The rotating portion 41 included in the rotation sensor 4 is a rotating member among the members that constitute the rotation sensor 4. In this way, in the in-wheel motor unit 1, the single housing 5 serves as both the housing that houses the motor 2 and the housing that houses the rotation sensor 4.

[0019] The housing 5 has an inner circumferential disk portion 52 extending radially inward from one axial end of the partition portion 51, and an outer circumferential disk portion 53 extending radially outward from the other axial end of the partition portion 51. The inner circumferential disk portion 52 extends radially inside the motor 2. A bearing 61 is attached to the inner circumferential portion of the disk portion 52. The outer circumferential disk portion 53 extends radially in a position axially opposite the motor 2. The disk portion 53 extends radially outside the cover 8 in the radial direction. A bearing 63 is attached to the outer circumferential portion of this disk portion 53. The bearing 63 and the cover 8 are positioned so as to overlap in the axial direction.

[0020] A cover 8 is attached to the housing 5 so as to axially partition the space that houses the rotation sensor 4. The cover 8 is fixed to the housing 5 so as to close an opening on one axial side of the partition portion 51 (the opening on the vehicle inner side). The cover 8 is fixed to the housing 5 by, for example, bolting.

[0021] The reducer 3 is a power transmission mechanism provided in the power transmission path between the motor 2 and the wheel 10. The reducer 3 is arranged alongside the motor 2 in the axial direction, with at least a portion of it located inside the wheel 11. The reducer 3 and the rotation sensor 4 are arranged in a position where they overlap in the axial direction. With regard to the positional relationship between the motor 2 and the reducer 3, the motor 2 is arranged relatively on the inside of the vehicle, and the reducer 3 is arranged relatively on the outside of the vehicle.

[0022] When transmitting the power of the motor 2 to the wheel 10, the reducer 3 reduces the rotation speed of the motor 2 and outputs the reduced speed to the output member 7. The output member 7 is connected to a rotating member (output element) on the output side of the reducer 3 and functions as the output member of the reducer 3. The output member 7 is connected to the wheel 11 so as to rotate integrally therewith. The output member 7 and the wheel 11 are fastened together with a plurality of bolts 9. The output member 7 has a hollow shaft portion and is disposed inside the rim portion of the wheel 11. The output member 7 is disposed along the central axis of rotation of the wheel 10 and is rotatably supported relative to the housing 5 by a bearing 63. The bearing 63 is a rolling bearing whose outer ring is attached to the output member 7 and whose inner ring is attached to the housing 5. The motor 2, the reducer 3, and the rotation sensor 4 are disposed inside the output member 7.

[0023] Shaft 6 is disposed on the central axis of rotation of wheel 10. Shaft 6 is rotatably supported relative to housing 5 and cover 8 by bearings 61 and 62. Bearing 61 is a rolling bearing with an outer ring attached to housing 5 and an inner ring attached to shaft 6. Bearing 62 is a rolling bearing with an outer ring attached to cover 8 and an inner ring attached to shaft 6.

[0024] As described above, according to embodiment 1, for an in-wheel motor unit 1 having a motor 2 in which the rotor 21 is arranged radially outside the stator 22, the rotation sensor 4 is located radially inside the stator 22, and the rotating part 41 included in the rotation sensor 4 is fixed to the shaft 6, and by providing the rotation sensor 4 on the shaft 6, it is possible to prevent the axial length of the motor 2 from becoming longer and to prevent the in-wheel motor unit 1 from becoming larger.

[0025] (Embodiment 2) A second embodiment of the driving device according to the present invention will be described below. In the description of the second embodiment, the same components as those in the first embodiment will not be described and their reference numerals will be used instead.

[0026] 2 is a diagram schematically showing an in-wheel motor unit 1 according to embodiment 2. The in-wheel motor unit 1 of embodiment 2 includes a brake 70 arranged inside the motor 2.

[0027] The brake 70 is a device that applies a braking force to the wheel 10, and is, for example, a non-excitation operated electromagnetic brake. In the in-wheel motor unit 1, the shaft 6 is provided in front of the reducer 3 (upstream of the reducer 3 in the power transmission path), so the brake 70 applies a braking force to the wheel 10 via the reducer 3 by braking the shaft 6. Therefore, the braking torque generated by the brake 70 is amplified by the reducer 3 and transmitted to the wheel 10. This amplification effect is the same when the motor 2 is powering or regenerating. During powering, the power torque generated by the motor 2 is amplified by the reducer 3 and transmitted to the wheel 10. During regeneration, the regenerative torque generated by the motor 2 is amplified by the reducer 3 and transmitted to the wheel 10. The motor 2 functions as a regenerative brake and can apply a braking force to the wheel 10.

[0028] Brake 70 is in an operating state where it brakes shaft 6 when not energized, and in a released state where it uses the magnetic attractive force generated when energized to release shaft 6 so that it can rotate. Brake 70 is a normally closed brake. Brake 70 includes a fixed plate 71, a pressing mechanism 72, a rotating disc 73, and brake wiring 74. The pressing mechanism 72 includes an electromagnetic coil, a yoke, a spring, an armature, etc.

[0029] The rotary disk 73 is connected to the shaft 6 so as to rotate integrally with the shaft 6. The rotary disk 73 is connected to the shaft 6 via a hub. The rotary disk 73, the hub, and the shaft 6 rotate integrally.

[0030] The electromagnetic coil is excited when energized. This electromagnetic coil is electrically connected to a power supply via brake wiring 74. This power supply is a common power supply for the motor 2. The yoke is a member that holds the electromagnetic coil. This yoke has a U-shaped cross section and is formed into an overall circular ring shape. The yoke has bolt holes through which bolts are inserted. The yoke is fixed to the housing 5 with the bolts, with the electromagnetic coil housed in the U-shaped portion. The spring is sandwiched between the yoke and the armature and applies a biasing force to the armature. This biasing force is a force in the engagement direction. The axial movement of this spring is restricted by the inner peripheral portion of the yoke. The armature is a disk-shaped plate member and is disposed between the rotating disk 73 and the electromagnetic coil. One surface of the armature faces the electromagnetic coil and the yoke in the axial direction, and the other surface of the armature faces the rotating disk 73 in the axial direction. A force is applied to the armature by the spring, pushing it towards the rotary disk 73 side.

[0031] For example, when the electromagnetic coil is energized, the magnetic attractive force generated by the energization attracts the armature toward the electromagnetic coil against the biasing force of the spring, causing it to move in the axial direction. When the electromagnetic coil is not energized, no magnetic attractive force is generated, so the armature is pushed in the engagement direction by the biasing force of the spring and pressed against the rotating disk 73. In this non-energized state, the biasing force of the spring clamps the rotating disk 73 between the armature and the fixed plate 71, and the brake 70 is activated.

[0032] The fixed plate 71 is an annular plate member fixed to the yoke, and functions as a brake plate that brakes the rotating disc 73. This fixed plate 71 is fixed to the yoke by a screw and a collar. The screw is inserted into the collar and threadedly engages with the yoke. The collar restricts the axial movement of the fixed plate 71 and supports the armature. The armature is supported by the collar so that it can move axially relative to the yoke, and is fixed non-rotatably by the screw. The fixed plate 71 is prevented from moving axially by the collar, and is fixed non-rotatably by the screw.

[0033] The brake wiring 74, connected to the electromagnetic coil, extends from the space that accommodates the brake 70, defined by the housing 5 and the cover 8, at a position above the center of rotation of the shaft 6, through the inside of the cover 8 in the axial direction, and then taken out to the outside of the cover 8. In the in-wheel motor unit 1, the motor 2 and the brake 70 are controlled by a common control unit. This control unit can control the motor 2 and the brake 70 using a common voltage command.

[0034] In the in-wheel motor unit 1 according to the second embodiment, an end of the shaft 6 communicates with the interior of the cover 8 in the axial direction, and the axial end face of the shaft 6 is exposed to the outside through the cover 8. A shaft portion 43 connected to a rotating portion 41 included in the rotation sensor 4 is fitted into a fitting hole provided in the axial end face of the shaft 6 and fixed so as to be coaxial with the rotation axis of the shaft 6. In this way, in the in-wheel motor unit 1 according to the second embodiment, the rotation sensor 4 is provided on the shaft 6 on the outside in the axial direction relative to the cover 8. A sensor wire 44 extending from the rotation sensor 4 is connected to a control unit that controls the motor 2 and the brake 70, and a signal corresponding to the detection result of the rotation of the shaft 6 detected by the rotation sensor 4 is output to the control unit via the sensor wire 44 and is used by the control unit to control the motor 2, the brake 70, etc.

[0035] As explained above, in the in-wheel motor unit 1 according to the second embodiment, it is possible to know the rotation speed and phase of the motor 2 by detecting the rotation of the shaft 6 with the rotation sensor 4, without increasing the axial length of the motor 2. Furthermore, by providing a small-diameter (compact) rotation sensor 4 for the brake 70, it is possible to prevent the in-wheel motor unit 1 from becoming larger. Furthermore, because the rotation sensor 4 is smaller in the radial direction than the brake 70, it is possible to route the brake wiring 74 from a position radially outside the rotation sensor 4 on the cover 8, as shown in FIG. 3 .

[0036] (Embodiment 3) A third embodiment of the driving device according to the present invention will be described below. In the description of the third embodiment, the same configurations as those of the first and second embodiments will be omitted and the same reference numerals will be used instead.

[0037] 4 is a diagram schematically showing an in-wheel motor unit 1 according to a third embodiment. In the in-wheel motor unit 1 according to the third embodiment, the rotation sensor 4 is disposed on the shaft 6, with a rotating part 41 included in the rotation sensor 4 fixed to the shaft 6, radially inside the stator 22. A sensor wiring 44 of the rotation sensor 4 extends from a space that accommodates the rotation sensor 4, defined by the housing 5 and the cover 8, at a position above the center of rotation of the shaft 6, through the inside of the housing 5, specifically through the inside of the partition part 51 and the disk part 53, and then taken out and extends to the outside of the housing 5 (disk part 53) in the axial direction.

[0038] In the in-wheel motor unit 1 according to the third embodiment, an end of the shaft 6 communicates with the interior of the cover 8 so as to protrude outside the cover 8 in the axial direction. A rotating disc 73 of the brake 70 is connected via a hub to the end of the shaft 6 protruding outside the cover 8. In the in-wheel motor unit 1 according to the third embodiment, the brake 70 includes a brake cover 75 that covers the fixed plate 71, the pressing mechanism 72, and the rotating disc 73, and the fixed plate 71 and the pressing mechanism 72 are fixed to the brake cover 75. The brake cover 75 is attached to the disk portion 53 of the housing 5. A brake wiring 74 of the brake 70 is taken out from inside the brake cover 75 and extends radially to the outside.

[0039] As explained above, in the in-wheel motor unit 1 according to the third embodiment, it is possible to know the rotation speed and phase of the motor 2 by detecting the rotation of the shaft 6 with the rotation sensor 4, without increasing the axial length of the motor 2. Furthermore, by installing a rotation sensor 4 that is small in diameter (compact) relative to the brake 70 inside the motor 2, it is possible to increase the diameter of the rotating disc 73 of the brake 70 outside the motor 2, and it is possible to mount the brake 70 with a large braking torque while preventing the in-wheel motor unit 1 from becoming larger.

[0040] Furthermore, by routing the sensor wiring 44 of the rotation sensor 4 through the inside of the housing 5 (partition portion 51 and disk portion 53) and extracting the sensor wiring 44 from a position radially outside the brake cover 75 on the disk portion 53 of the housing 5 as shown in Fig. 5, it is possible to increase the diameter of the rotating disk 73 of the brake 70, thereby increasing the holding torque and braking torque of the brake 70. Furthermore, the axial length of the brake 70 can be reduced, preventing the in-wheel motor unit 1 from becoming larger. [Explanation of symbols]

[0041] 1 In-wheel motor unit 2 motors 3 Reducer 4 Rotation Sensor 5. Housing 6 shafts 7 Output member 8 Cover 9 volts 10 wheels 11 Wheels 12 tires 23 Rotating member 23a Cylindrical part 23b Disc section 41 Rotating part 42 Fixed part 43 Shaft 44 Sensor wiring 51 Partition 52 Disc Section 53 Disc Section 70 Brake 71 Fixing plate 72 Pressing mechanism 73 Rotating Disk 74 Brake wiring 75 brake cover

Claims

[Claim 1] A drive device in which a motor having a rotor disposed radially outside a stator is provided in a wheel of a vehicle, a shaft disposed radially inside the stator and connected to the rotor via a rotating member; a rotation sensor provided on the shaft radially inside the stator and configured to detect rotation of the shaft; a housing that is a non-rotating member that accommodates the motor and the rotation sensor; a reducer arranged in line with the motor in the axial direction, at least a portion of which is arranged inside the wheel, and provided in a power transmission path between the motor and the wheel; an output member connected to a rotating element on an output side of the reducer, and disposed inside a rim portion of the wheel so as to rotate integrally with the wheel; It is equipped with the output member is rotatably supported relative to the housing, the housing has a cylindrical partition extending in an axial direction that radially divides a space that accommodates the motor and a space that accommodates the rotation sensor, the motor is disposed on the outer periphery side of the partition, and the rotation sensor is disposed on the inner periphery side of the partition, The stator is fixed to the outer peripheral surface of the partition portion on the outer peripheral side of the partition portion, a fixed portion included in the rotation sensor is fixed to the housing on an inner peripheral side of the partition portion, A driving device characterized in that a rotating part included in the rotation sensor is fixed to the shaft on the inner peripheral side of the partition part in the housing.

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