Differential with face gear for electric drive system
By using a combination of face gears and differentials in electric vehicles, along with a reduction gearbox, the problems of high cost and insufficient design flexibility of mechanical differentials are solved, achieving flexibility in torque transmission and compensation for wheel speed differences.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-13
- Publication Date
- 2026-04-07
AI Technical Summary
Existing mechanical differentials are costly and lack design flexibility when transmitting torque, making it difficult to meet the power output requirements of modern vehicles.
It adopts a combination of face gear and differential, and is connected to the drive wheel through the output shaft. It uses a pinion carrier and housing structure to realize the angular displacement and torque transmission of the output shaft, and combines with a reduction gearbox to adapt to different wheel speeds.
It achieves improved design flexibility and reduced costs while transmitting torque, and can effectively compensate for wheel speed differences when the vehicle is turning.
Smart Images
Figure CN121816684A_ABST
Abstract
Description
[0001] Cross-reference to related applications This application claims priority to U.S. Patent Application No. 18 / 368628, filed September 15, 2023, which is hereby expressly incorporated herein by reference in its entirety. Technical Field
[0002] This application relates to battery or hybrid electric vehicles and (more particularly) to differentials for such vehicles. Background Technology
[0003] Vehicles typically employ mechanical differentials to transfer rotational forces from the engine to the wheels, while also compensating for varying wheel speeds at different angles during cornering. Depending on the power output of modern vehicles, mechanical differentials can be designed to handle the substantial torque transmitted from the engine. The gear design included in the differential can be chosen to robustly handle torque, depending on the level of torque received by the differential. For example, a differential can use bevel gears to reliably transmit torque from the engine to the wheels. However, the use of bevel gears can be very expensive. Helpfully, drive systems with greater design flexibility allow for the use of other gear designs while still ensuring robust torque transmission to the wheels. Summary of the Invention
[0004] In one implementation, an electric drive system in a battery electric vehicle (BEV) includes: an output shaft configured to be coupled to the drive wheel of the BEV and having a face gear at a distal end; a differential including a pinion carrier housing a pinion rotatably connected to the pinion carrier via a gear pin; and a housing housing the differential having an outer surface configured to be coupled to a rotary motor of the BEV, wherein the pinion engages the face gear and allows angular displacement of the output shaft relative to another output shaft.
[0005] In another implementation, an electric drive system in a BEV includes: an output shaft configured to be coupled to the drive wheel of the BEV and having a face gear at a distal end; a differential including a pinion carrier housing a pinion rotatably connected to the pinion carrier via a gear pin; a housing housing the differential and having an outer surface configured to be coupled to a rotary motor of the BEV; and one or more reduction gearboxes coupled to the output shaft and configured to be coupled to the drive wheel of the BEV, wherein the pinion engages the face gear and allows angular displacement of the output shaft relative to another output shaft. Attached Figure Description
[0006] Figure 1 It is a block diagram depicting how a battery electric vehicle (BEV) with a differential is implemented; Figure 2This is a schematic diagram depicting the implementation of an electric drive system, including a differential, in a BEV; Figure 3 It is a perspective view depicting the implementation of a differential in an electric drive system used in a BEV; Figure 4 It is a cross-sectional view depicting the implementation of a differential in an electric drive system used in a BEV; Figure 5 It is a perspective view depicting the implementation of a portion of the differential used in the electric drive system of a BEV; Figure 6 It is a perspective view depicting the implementation of a portion of the differential used in the electric drive system of a BEV; Figure 7 This is a perspective view depicting the implementation of a portion of the differential used in an electric drive system of a BEV; and Figure 8 It is a cross-sectional view depicting the implementation of a portion of the differential used in the electric drive system of a BEV; Figure 9 It is a cross-sectional view depicting the implementation of a portion of the differential used in the electric drive system of a BEV. Detailed Implementation
[0007] Battery electric vehicles (BEVs) may include an electric motor directly coupled to a differential using face gears to drive multiple wheels of the BEV. The differential may be coupled substantially coaxially with the output shaft of the electric motor. One or more gear sets are coupled between the output of the differential and the drive wheels of the BEV, such that the gear ratio between the wheels and the output of the differential allows for a load within the rated load value of the face gears. In one example, the gear ratio between the output shaft of the electric motor and the drive wheel may be eight to one or greater.
[0008] See Figure 1 This illustrates an implementation of a battery electric vehicle (BEV). The BEV 10 can be detachably connected to and receive power from a power grid 12. The power grid 12 may include any of a variety of power generators and transmission mechanisms. A generator (not shown) produces AC power, which can then be transmitted over long distances for residential and commercial use. The generator can be connected to the power grid 12, which transmits AC power from the generator to end users, such as residences or businesses.
[0009] BEV 10 includes an electric drive system 14, which includes one or more rotating motors (also referred to as electric motors) having a stator with stator windings and a rotor (not shown) that is angularly displaceable relative to the stator. The rotor may be coupled to a differential, which may be concentrically positioned about the rotor such that the outer surface of the differential is concentrically received by the radially inward surface of the rotor. In one implementation, the rotating motor is a permanent magnet synchronous motor, which includes a rotor having a plurality of angularly spaced permanent magnets. The permanent magnets may be made of any of many different materials, one example being neodymium alloys or other rare earth elements. The electric drive system 14 may also include a differential and one or more transmissions, as described in more detail below. The stator windings may receive current, the supply of which may be regulated by a control system 16, which induces angular displacement of the rotor relative to the stator. The control system 16 may include a set of power control electronics and a microprocessor to facilitate the operation of the rotating motor 16. These electronic devices may include an inverter implemented using multiple MOSFETs, which are turned on and off in a coordinated sequence and timing under the guidance of a motor controller to induce angular movement of the rotor. The control system 16 may output a current command that regulates the current supplied from the vehicle battery 20 to the rotating motor 14. The current command may be implemented using one or more microprocessors having input / output terminals and non-volatile memory in which data can be stored and accessed. The control system 16 may also include a DC-DC converter to regulate the voltage level of the power supplied to the motor 14.
[0010] BEV service equipment (not shown), also known as a BEV charging station, receives AC power from the grid 12 and supplies power to the BEV 10. A wire 18 is detachably connected to a plug-in interface on the BEV 10 and electrically links the BEV charging station to the vehicle battery 20, allowing AC power to be transferred between the charging station and the vehicle battery 20, rectified into DC power, and then used to charge the vehicle battery 20. The BEV charging station can be classified as a "Level 2" BEV service equipment, receiving 240 VAC from the grid 12 and supplying 240 V AC to the BEV 10, where the AC power is rectified. In other implementations, the class of AC power input to and / or output from the charging station may be different.
[0011] The term "battery electric vehicle" or "BEV" can refer to a vehicle that is wholly or partially propelled by a rotary or electric motor. BEV can refer to electric vehicles, plug-in electric vehicles, hybrid electric vehicles, and battery-powered vehicles. The vehicle battery 20 supplies DC power, converted from AC power, to one or more motors 14 that propel the BEV 10. As described above, the control system 16 converts the DC power back to AC power to induce angular movement of the rotor relative to the stator. The vehicle battery 20 or more batteries are rechargeable and, for example, may include lead-acid batteries, nickel-cadmium (NiCd) batteries, nickel-metal hydride batteries, lithium-ion batteries, and lithium polymer batteries. Typical BEV battery voltages range from 200 VDC to 800 VDC. The term "electric drive system" can include not only electric motors but also inverters, vehicle batteries, and other electrical components of the BEV.
[0012] Figure 2 The implementation of an electric drive system 14 used in a BEV 10 is depicted. The electric drive system 14 may include a rotary motor 22, a differential 24, and a reduction gearbox 26 connecting the differential 24 and the drive wheels 28 of the BEV 10. The rotary motor 22 includes a stator 32 having stator windings housed in slots within the stator 32. The rotary motor 22 may also include a rotor 34 having an inner diameter 36 (shown in the figure) configured to engage with the differential 24 and transfer rotational movement of the rotor 34 to the differential 24. Figure 4 (Middle). The rotor 34 is housed within the stator 32 such that when the stator windings receive current, the rotor 34 is angularly displaced relative to the stator 32.
[0013] The differential 24 includes a pinion carrier 38, a pinion 40, a pinion pin 42 holding the pinion 40 in the carrier 38, two output shafts 44, and a housing 46, as shown. Figures 3 to 9As shown, the pinion carrier 38 may have a substantially cylindrical shape and a ring gear 48 circumferentially positioned around the outer surface 50 of the carrier 38. The ring gear 48 may include radially outward gear teeth. The pinion carrier 38 may include a plurality of spokes 52 and a central hub 54 that together define a pinion slot 56 circumferentially positioned within the carrier 38 between the spokes 52 and shaped to receive a pinion 40. An aperture 58 in the outer axial surface 60 of the pinion carrier 38 may be shaped to fit snugly to the outer surface of a pin 42, and a socket 62 in the hub 54 may be shaped to receive one end of the pin 42. The pinion 40 may be positioned in the slot 56 such that the pin 42 may be pushed through the aperture 58 and the central axis of the pin 40, such that the aperture 58 and the socket 62 hold the pin 42 together with the pin 40 in place. In this implementation, the pinion carrier 38 includes five pinions 40, but differentials with different numbers of pinions are possible. The pinion 40 may have a bore 64 and radially outward gear teeth circumferentially surrounding the pinion 40. In one implementation, the gear teeth may be spur gear teeth. The number of gear teeth on the pinion 40 may be selected based on various factors, such as the number of teeth on the face gear 66 included in the output shaft 44.
[0014] The output shaft 44 may include a face gear 66 having gear teeth shaped to mesh with the gear teeth of the pinion 40. The face gear 66 may be positioned at the distal end of the output shaft 44 and has a disc-shaped surface 68 substantially perpendicular to the axis of rotation (x) of the output shaft and substantially parallel to the gear face of the pinion 40. In one implementation, the output shaft 44 may be cast from metal and include an annular shoulder 70 in which spur gear teeth are formed during casting. In other implementations, the annular shoulder 70 and the disc-shaped surface 68 may be relatively smooth, wherein the spur gear teeth are cut into the surface 68 after casting.
[0015] The housing 46 may be substantially tubular, having cavities for accommodating the differential 24 and the output shaft 44. The outer surface of the housing 46 may engage with the rotor 34 to prevent angular displacement of the housing 46 relative to the rotor 34. In this implementation, the housing 46 may be concentrically accommodated and mechanically attached to the rotor 34 such that when the rotor 34 rotates relative to the stator 32, the housing 46 also rotates. The housing 46 may be made of any of a variety of materials, such as metal alloys. At the midpoint of the axial direction of the housing 46, a radially inward surface may include gear teeth shaped to engage the ring gear 48 on the pinion carrier 38, thereby preventing angular displacement of the carrier 38 relative to the housing 46 when the carrier 38 is accommodated within the housing 46. The face gear 66 of the output shaft 44 may be accommodated within the housing 46 such that the face gear 66 engages with the pinion 40, while one end of the output shaft 44 may extend beyond the housing 46 to engage with the input end 72 of the reduction gearbox 26 (shown in…). Figure 2(Middle). The bearing 74 can be positioned within the housing 46 about the outer surface of the output shaft 44 and engages the radially inward surface of the housing 46 to provide support. A C-shaped retaining ring 76 can be received within a groove included in the housing 46 to axially restrain the components received within the housing 46.
[0016] Back Figure 2 The reduction gearbox 26 connects the output shaft 44 from the differential 24 to the drive wheel 28 of the BEV 10. The gear reduction amount can be selected based on the torque load allowed by the face gear 66 of the engagement pinion 40. In one implementation, the reduction gearbox 26 has a gear reduction ratio greater than eight to one, meaning that for every eight revolutions of the output shaft 44, the drive wheel 28 rotates once, and also meaning that the drive wheel 28 receives eight times the amount of torque applied to the output shaft 44. It is possible that other implementations use even larger gear ratios. Furthermore, it should be recognized that the reduction gearbox 26 can be implemented in any of many ways. In this implementation, the reduction gearbox 26 can be a two-stage reduction gearbox with three shafts. The input shaft 78 includes a drive gear 80, which is smaller than the driven gear 82 connected to the intermediate shaft 84. The intermediate shaft 84 may include a drive gear 80 that engages with a driven gear 82 on a gearbox output shaft 86, which is ultimately connected to the drive wheel 28 of the BEV 10. The drive gear 80 may have a smaller diameter and fewer teeth than the driven gear 82.
[0017] As the rotor 34 rotates relative to the stator 32 in response to current flow through the stator windings, the housing 46 rotates, thereby transmitting torque to the differential 24. The housing 46 transmits torque to the pinion carrier 38, which in turn transmits it to the face gear 66 of the output shaft 44 via the pinion 40. The output shaft 44 can rotate the drive wheel 28 via the reduction gearbox 26. During BEV 10 operation, one drive wheel 28 can rotate at a different speed than the other. The differential 24 compensates for this difference in angular velocity between the output shafts 44 by the rotation of the pinion 40, which allows for angular displacement of one output shaft relative to the other.
[0018] It should be understood that the foregoing description is of one or more embodiments of the present invention. The invention is not limited to the specific embodiments disclosed herein, but is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to specific embodiments and should not be construed as limiting the scope of the invention or the definition of the terms used in the claims, except where the terms or phrases are expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiments will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to fall within the scope of the appended claims.
[0019] As used in this specification and claims, the term "for example" ("e.g.") is used in conjunction with a list of one or more components or other items. e.g. The words “…”, “for example”, “for instance”, “such as”, and “for instance”, as well as the verbs “including,” “have,” “contain,” and their other verbal forms, should each be interpreted as open-ended, meaning that the contents of this list should not be understood as excluding other, additional components or items. They should be interpreted using the broadest reasonable meaning of other terms, unless they are used in a context that requires a different interpretation.
Claims
1. An electric drive system in a battery electric vehicle (BEV), comprising: The output shaft is configured to connect to the drive wheel of the BEV and has a face gear at the distal end; A differential including a pinion carrier housing a pinion rotatably connected to the pinion carrier via a pinion pin; as well as A housing that houses the differential has an outer surface configured to be coupled to a rotary motor of the BEV, wherein the pinion engages the face gear and allows angular displacement of the output shaft relative to another output shaft.
2. The electric drive system according to claim 1, wherein the rotor of the rotary motor is concentrically housed within the housing.
3. The electric drive system according to any one of the preceding claims, wherein the gear ratio between the drive wheel and the output shaft of the BEV is greater than or equal to eight to one.
4. The electric drive system according to any one of the preceding claims, wherein the pinion carrier includes a central hub, spokes, a pinion groove, and an aperture on the outer surface of the pinion carrier, the aperture receiving the pinion pin and rotatably fixing the pinion relative to the pinion carrier.
5. The electric drive system of claim 4, further comprising a socket in the central hub, the socket receiving the gear pin.
6. The electric drive system according to any one of the preceding claims further includes a bearing positioned between the outer surface of the output shaft and the housing.
7. The electric drive system according to any one of the preceding claims further includes a C-shaped retaining ring for axially fixing the pinion carrier and the face gear within the housing.
8. The electric drive system according to any one of the preceding claims, wherein the output shaft extends along the output shaft axis, and wherein the face gear has a surface that engages the pinion, the surface being substantially perpendicular to the output shaft axis.
9. The electric drive system of claim 8, wherein the surface of the face gear engaging the pinion is perpendicular to the output shaft axis.
10. The electric drive system according to any one of claims 8 and 9, wherein the surface of the face gear engaging the pinion is a disc-shaped surface.
11. The electric drive system according to any one of the preceding claims, comprising the rotary motor, wherein the rotary motor comprises a stator and a rotor housed within the stator.
12. The electric drive system according to any one of the preceding claims, wherein the housing is substantially tubular.
13. The electric drive system according to any one of the preceding claims further includes one or more reduction gearboxes, said one or more reduction gearboxes being coupled to the output shaft and configured to be coupled to the drive wheel of the BEV.
14. The electric drive system of claim 13, wherein the gear ratio between the drive wheel and the output shaft of the BEV is greater than or equal to eight to one.
15. The electric drive system according to any one of claims 13 and 14, wherein the one or more reduction gearboxes are two-stage reduction gearboxes.