unit

Abstract

The present application provides a unit that realizes a reduction in the radial dimension of the unit and improves the acoustic vibration performance when the radial dimension of the unit is reduced. The unit includes a first motor, a second motor, a first planetary gear mechanism connected to the first motor, a second planetary gear mechanism connected to the second motor, and a housing that accommodates the first motor, the second motor, the first planetary gear mechanism, and the second planetary gear mechanism. The first motor, the second motor, the first planetary gear mechanism, and the second planetary gear mechanism are coaxially arranged, and are configured such that the rotational phase of a first pinion relative to a first ring gear of the first planetary gear mechanism is offset from the rotational phase of a second pinion relative to a second ring gear of the second planetary gear mechanism.

Description

Technical Field

[0001] This invention relates to units. Background Technology

[0002] Patent Document 1 discloses a vehicle drive unit having a pair of rotary motors and a pair of planetary gear mechanisms that independently drives the left and right wheels.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-139577 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, in the vehicle drive system of Patent Document 1, gear pairs are provided separately to transmit the driving force from a pair of rotating motors to the left and right wheels respectively. Therefore, there is a possibility that the vehicle drive system can be made larger.

[0008] The purpose of this invention is to reduce the radial dimension of the unit and improve the acoustic performance when the radial dimension of the unit is reduced.

[0009] Technical solutions for solving technical problems

[0010] According to one aspect of the invention, the unit comprises: a first electric motor; a second electric motor; a first planetary gear mechanism connected to the first electric motor; a second planetary gear mechanism connected to the second electric motor; and a housing that accommodates the first electric motor, the second electric motor, the first planetary gear mechanism, and the second planetary gear mechanism, wherein the unit is configured such that the rotational phase of the first pinion of the first planetary gear mechanism relative to the first ring gear is offset from the rotational phase of the second pinion of the second planetary gear mechanism relative to the second ring gear.

[0011] Invention Effects

[0012] According to one aspect of the present invention, the first electric motor, the second electric motor, the first planetary gear mechanism, and the second planetary gear mechanism are coaxially arranged, so the constituent components are not arranged radially. Therefore, the radial dimension of the unit can be reduced. Furthermore, the rotational phase shift between the first gear ring of the first planetary gear mechanism and the second gear ring of the second planetary gear mechanism, which are configured to be coaxially arranged, allows the position of the peak value of the vibration waveform generated by the rotation of the pinion to shift. Therefore, it is possible to prevent the peak values ​​of the vibration waveform from overlapping and thus amplifying the vibration, thereby improving acoustic performance. Therefore, it is possible to reduce the radial dimension of the unit and improve the acoustic performance when the radial dimension of the unit is reduced. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating the outline of the units in an embodiment of the present invention.

[0014] Figure 2 This is a structural diagram illustrating the first gear ring of the first planetary gear mechanism.

[0015] Figure 3 This is a structural diagram illustrating the second gear ring of the second planetary gear mechanism.

[0016] Figure 4 This is a structural diagram showing the state in which the first ring gear of the first planetary gear mechanism and the second ring gear of the second planetary gear mechanism overlap in the direction of rotation axis. Detailed Implementation

[0017] Hereinafter, the driving unit 1, which is a unit of an embodiment of the present invention, will be described with reference to the accompanying drawings.

[0018] First, refer to Figure 1 The overall structure of drive unit 1 will be described. Figure 1 This is a schematic diagram illustrating the general outline of drive unit 1.

[0019] The drive unit 1 is applied to the vehicle 100 to drive a pair of drive wheels 2 of the vehicle 100 to rotate. The drive unit 1 includes a first electric motor 10, a second electric motor 20, a first planetary gear mechanism 30, a second planetary gear mechanism 40, and a housing 50.

[0020] The first electric motor 10, the second electric motor 20, the first planetary gear mechanism 30, and the second planetary gear mechanism 40 are arranged coaxially. "Coaxial arrangement" means that they are configured with the same center of rotation. That is, if multiple elements are arranged coaxially, they are configured to overlap each other when viewed from the direction of the rotation axis. As a result, the components are not arranged radially, thus enabling a reduction in the radial dimension of the drive unit 1.

[0021] The drive unit 1 transmits the output torque of the first motor 10 to one drive wheel 2 and the output torque of the second motor 20 to the other drive wheel 2, thereby driving a pair (in this case, left and right) drive wheels 2. The drive unit 1 can independently control the output torque of the first motor 10 and the output torque of the second motor 20.

[0022] The first motor 10 is housed within the housing 50. The first motor 10 is electrically connected to a battery (not shown) outside the drive unit 1 via an inverter (not shown), and receives power from the battery to function as a motor. Alternatively, the first motor 10 can also function as a generator. The first motor 10 has a rotor 11 and a stator 12.

[0023] The rotor 11 has a motor shaft 11a. The rotor 11 is rotatably supported on the housing 50 via bearings (not shown). The stator 12 is fastened to the inner wall of the housing 50 by a plurality of bolts (not shown).

[0024] The second motor 20 is housed within the housing 50. The second motor 20 is electrically connected to a battery outside the drive unit 1 via an inverter (not shown), receiving power from the battery to function as a motor. Additionally, the second motor 20 can also function as a generator. The second motor 20 has a rotor 21 and a stator 22.

[0025] The rotor 21 has a motor shaft 21a. The rotor 21 is rotatably supported on the housing 50 via bearings (not shown). The stator 22 is fastened to the inner wall of the housing 50 by a plurality of bolts (not shown).

[0026] The first planetary gear mechanism 30 is housed in the housing 50. The first planetary gear mechanism 30 is connected to the first electric motor 10. The first planetary gear mechanism 30 has a sun gear 31 as a first sun gear, a plurality of pinions 32 as first pinions, a planet carrier 33 as a first planet carrier, and a ring gear 34 as a first ring gear.

[0027] The sun gear 31 is connected to the motor shaft 11a of the first motor 10. The output torque of the first motor 10 is transmitted to the sun gear 31 via the motor shaft 11a. The sun gear 31 meshes with a plurality of pinions 32.

[0028] Multiple pinions 32 rotate on their own axis and revolve around the sun gear 31 by transmitting the rotation of the sun gear 31. The multiple pinions 32 mesh with the ring gear 34.

[0029] The planet carrier 33 is rotatably supported on the housing 50 via bearings (not shown). The planet carrier 33 rotates as the pinion 32 revolves around the sun gear 31. The rotation of the planet carrier 33 is transmitted to the drive wheel 2 via the drive shaft 2a.

[0030] The gear ring 34 is fixed to the inner wall of the housing 50 via a spline structure 35. Alternatively, the gear ring 34 can be fastened to the inner wall of the housing 50 using multiple bolts (not shown).

[0031] The second planetary gear mechanism 40 is housed within the housing 50. The second planetary gear mechanism 40 is connected to the second electric motor 20. The second planetary gear mechanism 40 has a sun gear 41 as a second sun gear, a plurality of pinions 42 as second pinions, a planet carrier 43 as a second planet carrier, and a ring gear 44 as a second ring gear.

[0032] The sun gear 41 is connected to the motor shaft 21a of the second motor 20. The output torque of the second motor 20 is transmitted to the sun gear 41 via the motor shaft 21a. The sun gear 41 meshes with a plurality of pinions 42.

[0033] Multiple pinions 42 rotate on their own axes and revolve around the sun gear 41 by transmitting the rotation of the sun gear 41. The multiple pinions 42 mesh with the ring gear 44.

[0034] The planet carrier 43 is rotatably supported on the housing 50 via bearings (not shown). The planet carrier 43 rotates as the pinion 42 revolves around the sun gear 41. The rotation of the planet carrier 43 is transmitted to the drive wheel 2 via the drive shaft 2a.

[0035] The gear ring 44 is fixed to the inner wall of the housing 50 via a spline structure 45. Alternatively, the gear ring 44 can be fastened to the inner wall of the housing 50 using multiple bolts (not shown).

[0036] The housing 50 is composed of one or more components. That is, the housing 50 may also be composed of multiple components. The housing 50 internally houses the first electric motor 10, the second electric motor 20, the first planetary gear mechanism 30, and the second planetary gear mechanism 40. The housing 50 is fixed to the vehicle 100 without rotation.

[0037] Next, refer to Figures 2 to 4 The configuration of the gear ring 34 of the first planetary gear mechanism 30 and the gear ring 44 of the second planetary gear mechanism 40 will be described. Figure 2 This is a structural diagram illustrating gear ring 34. Figure 3 This is a structural diagram illustrating gear ring 44. Figure 4 This is a structural diagram showing the state in which gear ring 34 and gear ring 44 overlap in the direction of the rotation axis.

[0038] like Figure 2 As shown, the gear ring 34 of the first planetary gear mechanism 30 has an internal gear 34a. The internal gear 34a is formed into a ring shape on the inner circumference of the gear ring 34 by alternately arranging teeth 34b and tooth grooves 34c.

[0039] like Figure 3 As shown, the gear ring 44 of the second planetary gear mechanism 40 has an internal gear 44a. The internal gear 44a is formed into a ring shape on the inner circumference of the gear ring 44 by alternately arranging teeth 44b and tooth grooves 44c.

[0040] The circular pitch of the internal gear 34a of the gear ring 34 is set to be equal to the circular pitch of the internal gear 44a of the gear ring 44. "Circular pitch" is the interval between teeth 34b (tooth 44b) and refers to the width of the tooth groove 34c (tooth groove 44c).

[0041] like Figure 4 As shown, when viewed from the direction of the rotation axis, the teeth 34b of the internal gear 34a of the gear ring 34 of the first planetary gear mechanism 30 overlap with the tooth grooves 44c of the internal gear 44a of the gear ring 44 of the second planetary gear mechanism 40. Therefore, even assuming that the pinion 32 and the pinion 42 revolve around the same point on the circumference, they will not be in the same rotational phase because the internal gear 34a of the gear ring 34 and the internal gear 34a of the gear ring 44 are at opposite angles.

[0042] "Rotation phase" refers to the timing of the engagement of pinion 32 and ring gear 34 (and the timing of the engagement of pinion 42 and ring gear 44). In other words, "rotation phase offset" means that in the left and right planetary gear mechanisms 30 and 40, the timing of the engagement of pinion 32 and ring gear 34 and the timing of the engagement of pinion 42 and ring gear 44 are staggered.

[0043] Thus, the rotational phase of the pinion 32 relative to the ring gear 34 of the first planetary gear mechanism 30 is offset from the rotational phase of the pinion 42 relative to the ring gear 44 of the second planetary gear mechanism 40.

[0044] Therefore, by shifting the rotational phase of the first planetary gear mechanism 30 and the second planetary gear mechanism 40, the position of the peak value of the vibration waveform generated by the rotation of the pinions 32 and 42 in the two planetary gear mechanisms 30 and 40 is shifted. Since the first planetary gear mechanism 30 and the second planetary gear mechanism 40 are coaxially configured, even when the peak values ​​of the vibration waveform are at the same position, the vibration is amplified due to the overlap of the peak values ​​of the vibration waveforms because the two planetary gear mechanisms 30 and 40 are arranged in the direction of the rotation axis. However, due to the shift in the position of the peak values ​​of the vibration waveforms, the amplification of the vibration is suppressed, thereby improving the acoustic performance.

[0045] Furthermore, while achieving the effect of suppressing vibration amplification and improving acoustic performance, the peak position of the vibration waveform can be shifted by a simple method such as shifting the position of the teeth 34b and 42b of the gear rings 34 and 44. Therefore, one can enjoy the advantage of not needing complicated control.

[0046] More preferably, such as Figure 4As shown, the configuration is such that, when viewed from the direction of the rotation axis, the central portion of the tooth 34b of the internal gear 34a of the gear ring 34 overlaps with the central portion of the tooth groove 44c of the internal gear 44a of the gear ring 44. That is, the tooth 44b of the internal gear 44a of the gear ring 44 is located at the center between adjacent pairs of teeth 34b of the internal gear 34a of the gear ring 34. Furthermore, the tooth 34b of the internal gear 34a of the gear ring 34 is located at the center between adjacent pairs of teeth 44b of the internal gear 44a of the gear ring 44.

[0047] In this case, by overlapping the central portion of tooth 34b with the central portion of tooth groove 44c, the offset between teeth 34b and 42b of the two tooth rings 34 and 44 increases. If the offset increases, the amplification of vibration can be further suppressed, thus improving the sound vibration performance.

[0048] Here, by making the circular pitch of the gear ring 34 different from that of the gear ring 44, the positions of the teeth 34b and 44b of the gear rings 34 and 44 can also be shifted. However, in this case, when the two drive wheels 2 are rotated in the same way, the design difficulty of the two planetary gear mechanisms 30 and 40 increases.

[0049] In contrast, in drive unit 1, the circular pitch of the internal gear 34a of gear ring 34 is set to be equal to the circular pitch of the internal gear 44a of gear ring 44. By designing the circular pitches to be equal, the design difficulty can be reduced if the stop point and spline position of gear rings 34 and 44 are adjusted by offsetting teeth 34b and 42b during assembly.

[0050] The structure and effects of this implementation method are summarized above.

[0051] (1) The drive unit 1 includes: a first motor 10; a second motor 20; a first planetary gear mechanism 30 connected to the first motor 10; a second planetary gear mechanism 40 connected to the second motor 20; and a housing 50 that houses the first motor 10, the second motor 20, the first planetary gear mechanism 30 and the second planetary gear mechanism 40. The first motor 10, the second motor 20, the first planetary gear mechanism 30 and the second planetary gear mechanism 40 are coaxially arranged such that the rotational phase of the pinion 32 relative to the ring gear 34 of the first planetary gear mechanism 30 is offset from the rotational phase of the pinion 42 relative to the ring gear 44 of the second planetary gear mechanism 40.

[0052] According to this structure, the first motor 10, the second motor 20, the first planetary gear mechanism 30, and the second planetary gear mechanism 40 are arranged coaxially, so the components are not arranged radially. Therefore, the radial dimension of the drive unit 1 can be reduced.

[0053] Furthermore, by designing or controlling the structure, the rotational phases of the first planetary gear mechanism 30 and the second planetary gear mechanism 40 are shifted, thereby shifting the position of the peak value of the vibration waveform generated by the rotation of the pinions 32 and 42 in the two planetary gear mechanisms 30 and 40. Since the first planetary gear mechanism 30 and the second planetary gear mechanism 40 are coaxially configured, even when the peak values ​​of the vibration waveform are in the same position, the vibration is amplified due to the overlap of the peak values ​​of the vibration waveforms because the two planetary gear mechanisms 30 and 40 are arranged in the direction of the rotation axis. However, due to the shift in the position of the peak values ​​of the vibration waveforms, the amplification of the vibration is suppressed, thus improving the acoustic performance.

[0054] (2) The drive unit 1 includes: a first motor 10; a second motor 20; a first planetary gear mechanism 30 connected to the first motor 10; a second planetary gear mechanism 40 connected to the second motor 20; and a housing 50 that houses the first motor 10, the second motor 20, the first planetary gear mechanism 30, and the second planetary gear mechanism 40. The first motor 10, the second motor 20, the first planetary gear mechanism 30, and the second planetary gear mechanism 40 are coaxially arranged. When viewed from the direction of the rotation axis, the teeth 34b of the internal gear 34a of the gear ring 34 of the first planetary gear mechanism 30 are configured to have a portion that overlaps with the tooth groove 44c of the internal gear 44a of the gear ring 44 of the second planetary gear mechanism 40.

[0055] According to this structure, the first motor 10, the second motor 20, the first planetary gear mechanism 30, and the second planetary gear mechanism 40 are arranged coaxially, so the components are not arranged radially. Therefore, the radial dimension of the drive unit 1 can be reduced.

[0056] Furthermore, while achieving the effect of suppressing vibration amplification and improving acoustic performance, the peak position of the vibration waveform can be shifted by a simple method such as shifting the position of the teeth 34b and 42b of the gear rings 34 and 44. Therefore, one can enjoy the advantage of not needing complicated control.

[0057] (3) When viewed from the direction of rotation axis, the central portion of the tooth 34b of the internal gear 34a of the gear ring 34 has a portion that overlaps with the central portion of the tooth groove 44c of the internal gear 44a of the gear ring 44.

[0058] According to this structure, by overlapping the central portion of tooth 34b with the central portion of tooth groove 44c, the offset between teeth 34b and 42b of the two internal meshing gears 34 and 44 is increased. If the offset is increased, the amplification of vibration can be further suppressed, thus improving the acoustic performance.

[0059] (4) The circular pitch of the internal gear 34a of the gear ring 34 is set to be equal to the circular pitch of the internal gear 44a of the gear ring 44.

[0060] According to this structure, by making the circular pitch of gear ring 34 (the interval between teeth 34b (the width of tooth groove 34c)) and the circular pitch of gear ring 44 (the interval between teeth 44b (the width of tooth groove 44c)) different, the positions of teeth 34b and 44b of gear rings 34 and 44 can also be offset. However, in this case, the design difficulty of the two planetary gear mechanisms 30 and 40 increases when the two drive wheels 2 rotate in the same way. By designing the circular pitch to be equal, the design difficulty can be reduced if the dead center and spline position of gear rings 34 and 44 are adjusted by offsetting teeth 34b and 42b during assembly.

[0061] The embodiments of the present invention have been described above. However, the above embodiments are merely one example of the application of the present invention and do not imply that the technical scope of the present invention is limited to the specific structure of the above embodiments.

[0062] In the above embodiment, the rotational phase of the pinion 32 relative to the gear ring 34 is shifted relative to the gear ring 44 by a simple method of shifting the positions of the teeth 34b and 42b of the gear rings 34 and 44. Alternatively, the positions of the teeth 34b and 42b of the gear rings 34 and 44 may not be shifted, but the rotational phase of the pinion 32 relative to the gear ring 34 may be shifted relative to the gear ring 44 by controlling the rotational phase of the pinion 42 relative to the gear ring 44.

[0063] For example, sensors (not shown) that directly or indirectly detect the position of the tooth tips of pinions 32 and 42 are installed, and control is executed to shift the starting position of the rotation of the first motor 10 and the second motor 20 before rotation begins. Furthermore, the same control is executed during the rotation of the first motor 10 and the second motor 20 to ensure that pinions 32 and 42 are not simultaneously located at the same angle on the circumference. By controlling in this way, the rotational phase of pinion 32 relative to the gear ring 34 can be shifted from the rotational phase of pinion 42 relative to the gear ring 44.

[0064] Explanation of reference numerals in the attached figures

[0065] 1: Drive unit (unit)

[0066] 10: First electric motor

[0067] 20: Second electric motor

[0068] 30: First planetary gear mechanism

[0069] 32: Pinion (First Pinion)

[0070] 34: Gear ring (first gear ring)

[0071] 34a: Internal gear

[0072] 34b: teeth

[0073] 34c: Gear Alveolar

[0074] 40: Second planetary gear mechanism

[0075] 42: Pinion (Second pinion)

[0076] 44: Gear ring (second gear ring)

[0077] 44a: Internal gear

[0078] 44b: teeth

[0079] 44c: Tooth groove

[0080] 50: Outer shell

Claims

1. A unit, characterized in that, have: First electric motor; Second electric motor; A first planetary gear mechanism is connected to the first electric motor; The second planetary gear mechanism is connected to the second electric motor; A housing that accommodates the first electric motor, the second electric motor, the first planetary gear mechanism, and the second planetary gear mechanism. The unit is configured such that the rotational phase of the first pinion of the first planetary gear mechanism relative to the first gear ring is offset from the rotational phase of the second pinion of the second planetary gear mechanism relative to the second gear ring.

2. A unit, characterized in that, have: First electric motor; Second electric motor; A first planetary gear mechanism is connected to the first electric motor; The second planetary gear mechanism is connected to the second electric motor; A housing that accommodates the first electric motor, the second electric motor, the first planetary gear mechanism, and the second planetary gear mechanism. The first electric motor, the second electric motor, the first planetary gear mechanism, and the second planetary gear mechanism are coaxially arranged. The unit is configured such that, when viewed from the direction of the rotation axis, the teeth of the internal gear of the first gear ring of the first planetary gear mechanism have a portion that overlaps with the tooth grooves of the internal gear of the second gear ring of the second planetary gear mechanism.

3. The unit according to claim 2, characterized in that, When viewed from the direction of the rotation axis, the central portion of the tooth of the internal gear of the first gear ring has a portion that overlaps with the central portion of the tooth groove of the internal gear of the second gear ring.

4. The unit according to claim 2 or 3, characterized in that, The circular pitch of the internal gear of the first gear ring is set to be equal to the circular pitch of the internal gear of the second gear ring.

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