Two-speed transmission for electric vehicle using double planetary composite gear train

Abstract

The application discloses a two-gear transmission of an electric vehicle using a double planetary composite wheel system, which comprises a driving motor, a first speed reducer, a double planetary composite wheel system, a second speed reducer, a differential, a multi-plate friction clutch, a controllable one-way clutch, a first intermediate shaft, a second intermediate shaft and the like. The torque output by the driving motor is transmitted to the planetary carrier of the double planetary composite wheel system after the first speed reducer; the multi-plate friction clutch can realize the connection between the planetary carrier and the first intermediate shaft; the controllable one-way clutch is used for connecting the first intermediate shaft and the shell; the two sun gears of the double planetary composite wheel system are fixedly connected with the first intermediate shaft and the second intermediate shaft respectively; the torque after the gear shifting of the double planetary composite wheel system is transmitted to the differential through the second speed reducer. The two-gear transmission can realize seven states of one-gear driving, two-gear driving, neutral gear, one-gear regenerative braking, two-gear regenerative braking, reverse driving and parking braking by controlling the multi-plate friction clutch and the controllable one-way clutch.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicle transmission, and specifically relates to a highly integrated two-speed transmission for electric vehicles using a dual-planetary composite gear system. Background Technology

[0002] In recent years, with social development and progress, electric vehicles, characterized by zero fuel consumption, high integration, fast power response, and superior driving performance, have experienced rapid development and gradually gained market recognition. As the market expands and becomes more widespread, electric vehicles will continue to evolve towards high-end, high-performance, and diverse personalization, thus increasing the demand for advanced drive technologies that can improve chassis performance. One such technology is the two-speed transmission with seamless shifting in electric vehicles.

[0003] Currently, two-speed transmissions for electric vehicles have attracted considerable attention from scholars and manufacturers. Compared to the drive method of a single motor with a reducer, the use of a two-speed transmission can significantly reduce the maximum torque and maximum speed requirements of the drive motor, thereby reducing the size and cost of the motor. On the other hand, by optimizing the transmission ratio of a two-speed transmission, the utilization rate of the drive motor's high-efficiency range can be greatly improved, thereby improving the overall vehicle economy and increasing the driving range.

[0004] However, the use of stepped two-speed transmissions is accompanied by the problem of power interruption during gear shifts. To solve the problem of uninterrupted gear shifting in two-speed transmissions, some scholars have proposed a two-speed transmission scheme of "friction clutch + one-way overrunning clutch". However, if this scheme is applied to a single-axle drive electric vehicle, it cannot realize reversing and first-gear regenerative braking energy recovery. Therefore, some people have proposed a two-speed transmission scheme of "friction clutch + one-way overrunning clutch + claw clutch". However, this scheme has many actuators and a complex structure, and it is not easy to switch between first-gear regenerative braking and second-gear regenerative braking states during regenerative braking without regenerative braking power interruption. Therefore, to solve the above problems, this invention proposes a configuration scheme of "friction clutch + controllable one-way clutch".

[0005] Meanwhile, internal gear rings suffer from drawbacks such as low transmission efficiency, complex manufacturing process, and low production efficiency. To avoid using internal gear rings, this invention employs a double planetary compound gear system. Furthermore, to reduce additional friction losses, the controllable one-way clutch in this invention will be a non-contact controllable one-way clutch; simultaneously, to avoid oil churning losses, this invention fixes the driven part of the friction clutch to the inner ring of the one-way clutch to prevent its rotation in first gear.

[0006] In response to the aforementioned background, existing technical deficiencies, and technical expectations, this invention proposes a two-speed transmission for electric vehicles using a double planetary compound gear system. This transmission utilizes only two pairs of gears and one double planetary compound gear system, along with a controllable one-way clutch and a friction clutch. It can achieve seven different driving states: first gear drive, second gear drive, neutral, first gear regenerative braking, second gear regenerative braking, vehicle braking, and parking brake. Furthermore, it facilitates uninterrupted gear shifting during drive and uninterrupted downshifting during regenerative braking. Summary of the Invention

[0007] This invention provides a two-speed transmission for electric vehicles using a dual planetary compound gear system, which can realize seven different driving states: first-gear drive, second-gear drive, neutral, first-gear regenerative braking, second-gear regenerative braking, vehicle in neutral, and parking brake. This two-speed transmission can freely switch between different driving modes based on a controllable one-way clutch and a friction clutch, with low switching control difficulty. Simultaneously, this two-speed transmission avoids the use of an internal gear ring, reducing friction between the inner and outer rings of the one-way clutch and the oil churning loss of the friction clutch, thus improving the overall transmission efficiency of the system.

[0008] To achieve the above objectives, the following technical solution is adopted:

[0009] A two-speed transmission for an electric vehicle using a dual planetary composite gear train, characterized in that it includes: a drive motor, which is a hollow rotor shaft motor, arranged coaxially with the output shaft of the transmission at one end of the transmission, for outputting driving torque or electromagnetic braking torque;

[0010] The first reducer is used to reduce the torque output by the drive motor and increase its torque before outputting it.

[0011] A dual planetary composite gear train, arranged parallel to the output shaft of the transmission in the middle of the transmission, includes: a first sun gear, a first planet gear, a second sun gear, a second planet gear, a planet carrier, and a first intermediate shaft. The first planet gear and the second planet gear are integrally formed and rotatably supported on the planet carrier. The first sun gear and the second sun gear mesh with the first planet gear and the second planet gear respectively. The pitch circle radius of the first sun gear is smaller than that of the second sun gear. The planet carrier is fixedly connected to the output end of the first reducer. An integral first sun gear is machined on the inner end of the first intermediate shaft and is arranged coaxially and spaced apart from the second sun gear.

[0012] The second reducer receives torque from the second sun gear, reduces its speed, increases its torque, and then outputs it.

[0013] The differential is arranged coaxially with the output shaft of the transmission at the other end of the transmission. It receives the torque from the second reducer through the differential housing and distributes it evenly to the left and right half-shafts of the transmission and then to the left and right drive wheels.

[0014] A multi-plate friction clutch has its driving part fixedly connected to the planetary carrier and its driven part fixedly connected to the first intermediate shaft. When the hydraulic pressure pushes the pressing piston, the multi-plate friction clutch engages; when the hydraulic pressure unloads and releases the piston, the multi-plate friction clutch disengages.

[0015] The controllable one-way clutch has its outer ring fixedly connected to the housing and its inner ring fixedly connected to the first intermediate shaft. The controllable one-way clutch can be controlled to achieve a one-way lock-up state and can be controlled to switch from the one-way lock-up state to a two-way lock-up state or a two-way overrun state.

[0016] The transmission housing is used to house all components except the drive motor, and the drive motor is fixed to one end of the transmission housing. The left output shaft of the transmission extends from the left side of the transmission housing and passes through the rear flange of the hollow rotor shaft of the drive motor to connect to the left drive wheel of the vehicle. The right output shaft of the transmission extends from the right side of the transmission housing and connects to the rear flange of the right drive wheel of the vehicle.

[0017] The first intermediate shaft is rotatably supported on the transmission housing and supports the planetary carrier via needle roller bearings;

[0018] Preferably, the first reducer includes: a first driving gear and a first driven gear; the first driving gear and the first driven gear mesh and transmit power; the first driving gear is splinedly connected to the hollow rotor shaft of the drive motor; and the first driven gear is fixedly connected to the planetary carrier.

[0019] Preferably, the differential includes a differential housing, a plurality of planetary bevel gears, a left half-shaft bevel gear, and a right half-shaft bevel gear; the plurality of planetary bevel gears are rotatably supported on the differential housing; the left half-shaft bevel gear and the right half-shaft bevel gear mesh with the plurality of planetary bevel gears for transmission, and are respectively connected to the universal joint drive shafts of the left drive wheel and the right drive wheel through the left half-shaft and the right half-shaft, respectively.

[0020] Preferably, the second reducer includes: a second driving gear, a second driven gear, and a second intermediate shaft; the second driving gear meshes with the second driven gear; the second driving gear is splined and supported in the middle of the second intermediate shaft; the inner end of the second intermediate shaft is splinedly connected to the second sun gear; the second intermediate shaft is rotatably supported on the transmission housing, and supports the planetary carrier by needle roller bearings and the first intermediate shaft by bearings arranged in the countersunk hole at the center of the first sun gear; the second driven gear is fixedly connected to the differential housing.

[0021] Preferably, the controllable one-way clutch includes an inner ring, an outer ring, a plurality of first pawls, a plurality of second pawls, a plurality of return springs, a control disc, and a control mechanism;

[0022] The inner ring and the outer ring have a certain gap between them. The inner ring has a splined surface that is fixedly connected to the first intermediate shaft, and a bidirectional ratchet protrusion on its outer surface. The outer ring has a splined surface that is fixedly connected to the transmission housing. Multiple evenly staggered first pawls and multiple second pawls are installed on the inner surface. The first pawls and second pawls are installed in opposite directions. Each of the movable ends of the first pawls and second pawls is fixedly mounted with a control pin. A return spring is installed between the first pawl and the outer ring, and between the second pawl and the outer ring. The control pin cooperates with the control disc and can move radially within the space defined by the control disc under the drive of the control mechanism. The movable ends of the first pawls and second pawls can contact the bidirectional ratchet protrusion on the outer surface of the inner ring under the action of the return spring, thereby locking the inner ring from rotating counterclockwise and clockwise, respectively.

[0023] Preferably, the control disk is mounted on the side of the inner and outer rings and can rotate around the second intermediate axis. The control disk is machined with multiple sets of two different shaped control grooves arranged alternately on the circumference, which respectively cooperate with the control pins of the first pawl and the second pawl to constrain the spatial range of movement of each control pin. The total number of control pins is the same as the total number of control grooves. Specifically, when the control disk is in the middle position, the first pawl control pin is not controlled by the control groove, and the movable end of the first pawl is pushed against the bidirectional ratchet protrusion on the outer surface of the inner ring under the action of the return spring. Meanwhile, the second pawl control pin is controlled by the control groove, and the movable end of the second pawl is pushed outward under the action of the control groove, not contacting the bidirectional ratchet protrusion on the outer surface of the inner ring. At this time, the controllable... The one-way clutch is in a one-way locked state when the inner ring is locked by counterclockwise rotation. When the control disc rotates counterclockwise from the middle position by a certain angle, neither the first pawl control pin nor the second pawl control pin is controlled by the control groove. The movable ends of the first pawl and the second pawl are pushed against the bidirectional ratchet protrusion on the outer surface of the inner ring under the action of the return spring. At this time, the controllable one-way clutch is in a bidirectional locked state. When the control disc rotates clockwise from the middle position by a certain angle, both the first pawl control pin and the second pawl control pin are controlled by the control groove. The movable ends of the first pawl and the second pawl are pushed outward under the action of the control groove and do not contact the bidirectional ratchet protrusion on the outer surface of the inner ring. At this time, the inner and outer rings of the controllable one-way clutch are completely separated, and the one-way clutch is in a bidirectional overrunning state.

[0024] Preferably, the control mechanism includes: a worm gear, a worm, and a control motor. The worm gear has a fan-shaped spoke structure, and its spokes are fixedly connected to the control disk. The worm meshes with the worm gear for transmission. The control motor is fixedly connected to the worm. The output torque of the control motor is reduced and increased by the worm gear and the transmission direction is changed vertically to achieve rotational control of the control disk.

[0025] Preferably, when the two-speed transmission is in first gear, the multi-plate friction clutch is disengaged, the controllable one-way clutch is locked in both directions, and the drive motor outputs driving torque in the positive direction; when the two-speed transmission is in second gear, the multi-plate friction clutch is engaged, the controllable one-way clutch is overrunning in both directions, and the drive motor outputs driving torque in the positive direction; when the two-speed transmission is in neutral, the multi-plate friction clutch is disengaged, the controllable one-way clutch is overrunning in both directions, and the drive motor does not output any torque; when the two-speed transmission is in first gear regenerative braking mode, the multi-plate friction clutch is disengaged. In the following states: when the two-speed transmission is in second gear regenerative braking mode, the multi-plate friction clutch is engaged, the controllable one-way clutch is in bidirectional overrunning mode, and the drive motor outputs electromagnetic braking torque in the positive direction; when the two-speed transmission is in reverse mode, the multi-plate friction clutch is disengaged, the controllable one-way clutch is in bidirectional lock-up mode, and the drive motor outputs driving torque in the reverse direction; when the two-speed transmission is in parking brake mode, the multi-plate friction clutch is engaged, the controllable one-way clutch is in bidirectional lock-up mode, and the drive motor does not output any torque.

[0026] The one-way lock-up state of the controllable one-way clutch refers to all transition states when the two-speed transmission switches between first-speed drive and second-speed drive, and when it switches between first-speed regenerative braking and second-speed regenerative braking.

[0027] The beneficial effects of this invention are:

[0028] 1. The present invention provides a two-speed transmission for electric vehicles using a dual-planetary composite gear system, which can realize seven different driving states: first-gear drive state, second-gear drive state, neutral state, first-gear regenerative braking state, second-gear regenerative braking state, reverse driving state, and parking braking state; the two-speed transmission can freely switch between different driving modes based on a controllable one-way clutch and a multi-plate friction clutch, and the switching control is easy.

[0029] 2. The two-speed transmission for electric vehicles using a double planetary compound gear system described in this invention employs a non-contact controllable one-way clutch, which avoids friction between the inner and outer rings of the controllable one-way clutch in second gear. Simultaneously, in first gear, the driven part of the multi-plate friction clutch is in a non-rotating state, effectively avoiding oil churning losses. Furthermore, the two-speed transmission of this invention avoids the use of an internal gear ring, which suffers from low transmission efficiency, complex manufacturing processes, and low production efficiency. In summary, the two-speed transmission for electric vehicles using a double planetary compound gear system described in this invention can effectively improve the overall transmission efficiency of the transmission system.

[0030] 3. The electric vehicle two-speed transmission using a dual planetary compound gear system described in this invention can achieve shift control without power interruption and shift control without regenerative braking force interruption based on multi-plate friction clutch and controllable one-way clutch.

[0031] 4. The electric vehicle two-speed transmission using a dual planetary compound gear system described in this invention can achieve the parking requirement in non-stop and engine-off scenarios by controlling the engagement of a multi-plate friction clutch and the bidirectional locking of a controllable one-way clutch, thus solving the problems of poor dynamic response and high system energy consumption caused by the need to activate the hydraulic braking system when parking in conventional electric vehicles. Attached Figure Description

[0032] Figure 1 This is a simplified structural diagram of a two-speed transmission for an electric vehicle using a dual planetary composite gear train, as described in this invention.

[0033] Figure 2 This is a structural diagram of a two-speed transmission for an electric vehicle using a dual planetary composite gear train, as described in this invention.

[0034] Figure 3 This is a partial structural diagram of a controllable one-way clutch for a two-speed transmission of an electric vehicle using a dual planetary compound gear system, as described in this invention.

[0035] Figure 4 This is a structural diagram of a controllable one-way clutch control mechanism for a two-speed electric vehicle using a dual planetary compound gear train, as described in this invention.

[0036] Figure 5 This is a schematic diagram illustrating the one-way lock-up principle of a controllable one-way clutch in a two-speed electric vehicle transmission using a dual planetary compound gear system, as described in this invention.

[0037] Figure 6 This is a schematic diagram illustrating the principle of the controllable one-way clutch in the bidirectional lock-up state of a two-speed electric vehicle transmission using a dual planetary compound gear system, as described in this invention.

[0038] Figure 7This is a schematic diagram illustrating the principle of a controllable one-way clutch in a two-speed electric vehicle using a dual planetary compound gear train, as described in this invention.

[0039] Figure 8 This is a schematic diagram of the torque flow in the first gear driving state of a two-speed transmission for an electric vehicle using a dual planetary compound gear system, as described in this invention.

[0040] Figure 9 This is a schematic diagram of the torque flow of a two-speed transmission for an electric vehicle using a dual planetary compound gear system in second-speed driving mode, as described in this invention.

[0041] Figure 10 This is a schematic diagram of the torque flow in the first gear regenerative braking state of a two-speed transmission for an electric vehicle using a dual planetary compound gear train, as described in this invention.

[0042] Figure 11 This is a schematic diagram of the torque flow of a two-speed transmission for an electric vehicle using a dual planetary composite gear system in second gear regenerative braking state, as described in this invention. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description. An embodiment of a two-speed transmission for an electric vehicle using a dual planetary compound gear system according to the present invention is as follows:

[0044] like Figure 1 , Figure 2 The electric vehicle two-speed transmission using a dual planetary compound gear system mainly includes: a drive motor 100, a first reducer 200, a multi-plate friction clutch 300, a controllable one-way clutch 400, a dual planetary compound gear system 500, a second reducer 600, a differential 700, a left housing 901, a main housing 902, and a right housing 903, etc.

[0045] The drive motor 100, used to output driving and braking torque, includes an outer stator 101, an inner rotor 102, a drive motor output shaft 103, and a motor housing 104. The outer stator 101 is fixedly supported on the motor housing 104. The drive motor output shaft 103 is rotatably supported on the motor housing 104 and the left housing 901 through bearings. The inner rotor 102 is fixedly connected to the drive motor output shaft 103. In this invention, it is considered that when the drive motor 100 rotates counterclockwise when viewed from the right, the vehicle is in a forward driving state.

[0046] The first reducer 200 is used to reduce and increase the torque output by the drive motor 100 before outputting it to the double planetary compound gear train 500. The first reducer 200 includes: a first driving gear 201 and a first driven gear 202; the first driving gear 201 and the first driven gear 202 mesh and transmit power; the first driving gear 201 is fixedly connected to the output shaft 103 of the drive motor via a spline.

[0047] A double planetary composite gear train 500 includes: a first sun gear 501, a first planet gear 502, a second sun gear 504, a second planet gear 503, a planet gear shaft 505, a left planet carrier 506, and a right planet carrier 507. The first sun gear 501 and the second sun gear 504 are coaxially arranged and mesh with the first planet gear 502 and the second planet gear 503 respectively. The first planet gear 502 and the second planet gear 503 are integrally formed and rotatably supported on the planet gear shaft 505. The left planet carrier 506... The left planet carrier 506 and the right planet carrier 507 are respectively arranged on the left and right sides of the double planetary compound gear train 500 to fix and support the planetary gear rotation shaft 505; the left planet carrier 506 is rotatably supported on the first intermediate shaft 801, and the right planet carrier 507 is rotatably supported on the second intermediate shaft 802; the first sun gear 501 is integrally formed with the right end of the first intermediate shaft 801, and the second sun gear 504 is fixedly supported on the left end of the second intermediate shaft 802; the pitch circle radius of the first sun gear 501 is smaller than the pitch circle radius of the second sun gear 504.

[0048] The first driven gear 202 is integrated with the left planetary carrier 506.

[0049] The second reducer 600 reduces and increases the torque output from the double planetary compound gear train 500 before outputting it to the differential 700. The second reducer 600 includes a second intermediate shaft 802, a second drive gear 601, and a second driven gear 602. The middle part of the second intermediate shaft 802 is rotatably supported on the main housing 902 by a bearing, and the right end is rotatably supported on the right housing 903 by a bearing. The second drive gear 601 is fixedly supported on the second intermediate shaft 802 by a spline, and the second driven gear 602 meshes with the second drive gear 601 for transmission.

[0050] The differential 700 receives torque from the second reducer 600 and distributes it evenly to the left and right drive wheels; the differential 700 is coaxially arranged with the drive motor 100. In this embodiment, the differential 700 is a bevel gear differential, which includes: a left half-shaft bevel gear 701, a right half-shaft bevel gear 702, multiple planetary bevel gears 703, multiple planetary bevel gear shafts 704, and a differential housing 705. The differential housing 705 and the second driven gear 602 are integrally formed; multiple planetary bevel gear shafts 704 are fixedly supported on the differential housing 705, and multiple planetary bevel gears 703 are rotatably supported on the planetary bevel gear shafts 704; the left half-shaft bevel gear 701 and the right half-shaft bevel gear 702 are arranged on the left and right sides of the differential 700, and respectively mesh with the planetary bevel gears 703 for transmission; the left half-shaft bevel gear 701 is fixedly connected to the left half-shaft 803 through a spline, and the left half-shaft 803 passes through the hollow drive motor output shaft 103 and is fixedly connected to the left flange 805 through a spline; the left nut 807 is bolted to the left half-shaft 803 to fix the left flange 805; the right half-shaft bevel gear 702 is fixedly connected to the right half-shaft 804 through a spline, and the right half-shaft 804 is fixedly connected to the right flange 806 through a spline; the right nut 808 is bolted to the right half-shaft 804 to fix the right flange 806.

[0051] The multi-plate friction clutch 300 is used to connect the left planetary carrier 506 and the first intermediate shaft 801. It includes a driving part 301 and a driven part 302. The driving part 301 is fixedly connected to the left planetary carrier 506, and the driven part 302 is fixedly connected to the first intermediate shaft 801 via a spline.

[0052] The left end of the first intermediate shaft 801 is rotatably supported on the left housing 901 via a bearing, and the right end is rotatably supported on the second intermediate shaft 802 via a bearing.

[0053] like Figures 1-4As shown, the controllable one-way clutch 400 is used to connect the first intermediate shaft 801 and the left housing 901. It can achieve a one-way locking state and can be directly switched from the one-way locking state to a two-way locking state or a two-way overrunning state. The controllable one-way clutch 400 includes an inner ring 401, an outer ring 402, multiple first pawls 403, multiple second pawls 404, multiple return springs 405, a control disc 406, a worm gear 407, a worm 408, and a control motor 409. There is a certain gap between the inner ring 401 and the outer ring 402. The inner surface of the inner ring 401 is machined with splines and is fixedly connected to the first intermediate shaft 801, and the outer surface is machined with a two-way ratchet protrusion. The outer surface of the outer ring 402 is machined with splines and is fixedly connected to the left housing 901, and the inner surface is equipped with multiple first pawls 403 and multiple second pawls 404. Two pawls 404; the first pawl 403 and the second pawl 404 are installed in opposite directions, and control pins 403(a) and 404(a) are respectively installed on the movable ends of the first pawl 403 and the second pawl 404; a return spring 405 is installed between the first pawl 403 and the outer ring 402 and between the second pawl 404 and the outer ring 402; the movable ends of the first pawl 403 and the second pawl 404 can contact the bidirectional ratchet protrusion on the outer surface of the inner ring 401 under the action of the return spring 405, thereby locking the inner ring 401 from rotating counterclockwise and clockwise respectively.

[0054] The control disc 406 is mounted on the side of the inner ring 401 and the outer ring 402, and can rotate around the second intermediate shaft 801; the control disc 406 is machined with control grooves for controlling the first pawl 403 control pin 403(a) and the second pawl 404 control pin 404(a), specifically as follows: Figure 5 As shown, when the control panel 406 is in the middle position, the first pawl 403 control pin 403(a) is not controlled by the control groove on the control panel 406. The movable end of the first pawl 403 is pushed against the bidirectional ratchet protrusion on the outer surface of the inner ring 401 under the action of the return spring 405. Meanwhile, the second pawl 404 control pin 404(a) is controlled by the control groove on the control panel 406. The movable end of the second pawl 404 is pushed outward under the action of the control groove and does not contact the bidirectional ratchet protrusion on the outer surface of the inner ring 401. At this time, the controllable one-way clutch 400 is in a one-way locked state where the inner ring 401 is locked by counterclockwise rotation. Figure 6 As shown, when the control disk 406 rotates counterclockwise from the middle position by a certain angle, neither the first pawl 403 control pin 403(a) nor the second pawl 404 control pin 404(a) is controlled by the control groove on the control disk 406. Under the action of the return spring 405, the movable ends of the first pawl 403 and the second pawl 404 are pushed against the bidirectional ratchet protrusion on the outer surface of the inner ring 401. At this time, the controllable one-way clutch 400 is in a bidirectional locked state. Figure 7As shown, when the control disk 406 rotates clockwise from the middle position by a certain angle, the first pawl 403 control pin 403(a) and the second pawl 404 control pin 404(a) are both controlled by the control groove on the control disk 406. The moving ends of the first pawl 403 and the second pawl 404 are both pushed outward under the action of the control groove, and do not contact the bidirectional ratchet protrusion on the outer surface of the inner ring 401. At this time, the controllable one-way clutch 400 is in a bidirectional overrunning state.

[0055] The worm gear 407 is fixedly connected to the control disk 406, and the worm 408 meshes with the worm gear 407 for transmission. The control motor 409 is fixedly connected to the worm 408, and the control motor 409 can control the rotation of the control disk 406 through the worm 408 and the worm gear 407.

[0056] When the two-speed transmission is in first gear, the multi-plate friction clutch 300 is disengaged, the controllable one-way clutch 400 is in a bidirectional locked state, and the drive motor rotates in the forward direction, outputting positive torque. At this time, the torque transmission path of the two-speed transmission is as follows: Figure 8 As shown; when the two-speed transmission is in second gear, the multi-plate friction clutch 300 is engaged, the controllable one-way clutch 400 is in a bidirectional overrunning state, and the drive motor rotates in the forward direction, outputting positive torque. The torque transmission path of the two-speed transmission at this time is as follows: Figure 9 As shown; when the two-speed transmission is in neutral, the multi-plate friction clutch 300 is disengaged, the controllable one-way clutch 400 is in a bidirectional overrunning state, and the drive motor does not output torque; when the two-speed transmission is in first gear regenerative braking state, the multi-plate friction clutch 300 is disengaged, the controllable one-way clutch 400 is in a bidirectional locked state, the drive motor rotates in the forward direction and outputs reverse torque, and the torque flow transmission path of the two-speed transmission at this time is as follows. Figure 10 As shown; when the two-speed transmission is in second gear regenerative braking state, the multi-plate friction clutch 300 is engaged, the controllable one-way clutch 400 is in bidirectional overrunning state, and the drive motor rotates in the forward direction to output reverse torque. At this time, the torque flow transmission path of the two-speed transmission is as follows: Figure 11 As shown; when the two-speed transmission is in reverse, the multi-plate friction clutch 300 is disengaged, the controllable one-way clutch 400 is in a bidirectional locked state, and the drive motor rotates in the opposite direction to output reverse torque; when the two-speed transmission is in parking brake state, the multi-plate friction clutch 300 is engaged, the controllable one-way clutch 400 is in a bidirectional locked state, and the drive motor does not output torque; the one-way locked state of the controllable one-way clutch 400 is the transition state when switching between the first gear and the second gear of the two-speed transmission.

[0057] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A two-speed transmission for an electric vehicle using a dual planetary compound gear train, characterized in that, include: The drive motor is a hollow rotor shaft motor, which is coaxially arranged with the output shaft of the transmission at one end of the transmission, and is used to output drive torque or electromagnetic braking torque. The first reducer is used to reduce the torque output by the drive motor and increase its torque before outputting it. A dual planetary composite gear train, arranged parallel to the output shaft of the transmission in the middle of the transmission, includes: a first sun gear, a first planet gear, a second sun gear, a second planet gear, a planet carrier, and a first intermediate shaft. The first planet gear and the second planet gear are integrally formed and rotatably supported on the planet carrier. The first sun gear and the second sun gear mesh with the first planet gear and the second planet gear respectively. The pitch circle radius of the first sun gear is smaller than that of the second sun gear. The planet carrier is fixedly connected to the output end of the first reducer. An integral first sun gear is machined on the inner end of the first intermediate shaft and is arranged coaxially and spaced apart from the second sun gear. The second reducer receives torque from the second sun gear, reduces its speed, increases its torque, and then outputs it. The differential is arranged coaxially with the output shaft of the transmission at the other end of the transmission. It receives the torque from the second reducer through the differential housing and distributes it evenly to the left and right half-shafts of the transmission and then to the left and right drive wheels. A multi-plate friction clutch has its driving part fixedly connected to the planetary carrier and its driven part fixedly connected to the first intermediate shaft. When the hydraulic pressure pushes the pressing piston, the multi-plate friction clutch engages; when the hydraulic pressure unloads and releases the piston, the multi-plate friction clutch disengages. The controllable one-way clutch has its outer ring fixedly connected to the housing and its inner ring fixedly connected to the first intermediate shaft. The controllable one-way clutch can be controlled to achieve a one-way lock-up state and can be controlled to switch from the one-way lock-up state to a two-way lock-up state or a two-way overrun state. The transmission housing is used to house all components except the drive motor, and the drive motor is fixed to one end of the transmission housing. The left output shaft of the transmission extends from the left side of the transmission housing and passes through the rear flange of the hollow rotor shaft of the drive motor to connect to the left drive wheel of the vehicle. The right output shaft of the transmission extends from the right side of the transmission housing and connects to the right drive wheel of the vehicle. The first intermediate shaft is rotatably supported on the transmission housing and supports the planetary carrier via needle roller bearings; The electric vehicle two-speed transmission using a dual planetary compound gear system can operate in seven different driving states: first gear drive, second gear drive, neutral, first gear regenerative braking, second gear regenerative braking, reverse driving, and parking braking.

2. The two-speed transmission for an electric vehicle using a dual planetary composite gear train as described in claim 1, characterized in that, The first reducer includes: a first driving gear and a first driven gear; the first driving gear and the first driven gear mesh and transmit power; the first driving gear is splinedly connected to the hollow rotor shaft of the drive motor; and the first driven gear is fixedly connected to the planetary carrier.

3. The two-speed transmission for an electric vehicle using a dual planetary composite gear train as described in claim 1, characterized in that, The differential includes a differential housing, a plurality of planetary bevel gears, a left half-shaft bevel gear, and a right half-shaft bevel gear; the plurality of planetary bevel gears are rotatably supported on the differential housing; the left half-shaft bevel gear and the right half-shaft bevel gear mesh with the plurality of planetary bevel gears for transmission, and are respectively connected to the universal joint drive shafts of the left drive wheel and the right drive wheel through the left half-shaft and the right half-shaft, respectively.

4. A two-speed transmission for an electric vehicle using a dual planetary composite gear train as described in claim 1, characterized in that, The second reducer includes: a second driving gear, a second driven gear, and a second intermediate shaft; the second driving gear meshes with the second driven gear; the second driving gear is splined and supported in the middle of the second intermediate shaft; the inner end of the second intermediate shaft is splinedly connected to the second sun gear; the second intermediate shaft is rotatably supported on the transmission housing, and supports the planetary carrier by needle roller bearings and the first intermediate shaft by bearings arranged in the countersunk hole at the center of the first sun gear; the second driven gear is fixedly connected to the differential housing.

5. A two-speed transmission for an electric vehicle using a dual planetary composite gear train as described in claim 4, characterized in that, The controllable one-way clutch includes an inner ring, an outer ring, multiple first pawls, multiple second pawls, multiple return springs, a control disc, and a control mechanism; the control disc is mounted on the sides of the inner ring and the outer ring and can rotate around the second intermediate shaft. The inner ring and the outer ring have a certain gap between them. The inner ring has a splined surface that is fixedly connected to the first intermediate shaft, and a bidirectional ratchet protrusion on its outer surface. The outer ring has a splined surface that is fixedly connected to the transmission housing. Multiple evenly staggered first pawls and multiple second pawls are installed on the inner surface. The first pawls and second pawls are installed in opposite directions. Each of the movable ends of the first pawls and second pawls is fixedly mounted with a control pin. A return spring is installed between the first pawl and the outer ring, and between the second pawl and the outer ring. The control pin cooperates with the control disc and can move radially within the space defined by the control disc under the drive of the control mechanism. The movable ends of the first pawls and second pawls can contact the bidirectional ratchet protrusion on the outer surface of the inner ring under the action of the return spring, thereby locking the inner ring from rotating counterclockwise and clockwise, respectively.

6. A two-speed transmission for an electric vehicle using a dual planetary compound gear train as described in claim 5, characterized in that, The control panel is machined with multiple sets of two different shaped control grooves arranged alternately on the circumference, which respectively cooperate with the control pins of the first pawl and the second pawl to constrain the spatial range that each control pin can move. The total number of control pins is the same as the total number of control grooves. The constraint relationship is specifically manifested as follows: When the control panel is in the middle position, the first pawl control pin is not controlled by the corresponding control groove. The movable end of the first pawl is pushed against the bidirectional ratchet protrusion on the outer surface of the inner ring under the action of the return spring. At this time, the second pawl control pin is controlled by the corresponding control groove. The movable end of the second pawl is pushed outward under the action of the control groove and does not contact the bidirectional ratchet protrusion on the outer surface of the inner ring. At this time, the controllable one-way clutch is in a one-way locked state where the inner ring is locked by counterclockwise rotation. When the control plate rotates counterclockwise from the middle position by a certain angle, the first pawl control pin and the second pawl control pin are no longer controlled by their respective control slots. The movable ends of the first pawl and the second pawl are pushed against the bidirectional ratchet protrusion on the outer surface of the inner ring under the action of the reset spring. At this time, the controllable one-way clutch is in a bidirectional locked state. When the control disc rotates clockwise from the middle position by a certain angle, the first pawl control pin and the second pawl control pin are both controlled by their respective control grooves. The movable ends of the first pawl and the second pawl are both pushed outward under the action of the control grooves, and do not contact the bidirectional ratchet protrusion on the outer surface of the inner ring. At this time, the inner and outer rings of the controllable one-way clutch are completely separated, and the one-way clutch is in a bidirectional overrunning state.

7. A two-speed transmission for an electric vehicle using a dual planetary compound gear train as described in claim 5, characterized in that, The control mechanism includes a worm gear, a worm, and a control motor. The worm gear has a fan-shaped spoke structure, and its spokes are fixedly connected to the control disk. The worm meshes with the worm gear for transmission. The control motor is fixedly connected to the worm. The output torque of the control motor is reduced and increased by the worm gear and the transmission direction is changed vertically to achieve rotational control of the control disk.

8. A two-speed transmission for an electric vehicle using a dual planetary compound gear train as described in claim 1, characterized in that, When the two-speed transmission is in first gear, the multi-plate friction clutch is in a disengaged state, the controllable one-way clutch is in a bidirectional locked state, and the drive motor outputs drive torque in the positive direction. When the two-speed transmission is in second gear, the multi-plate friction clutch is engaged, the controllable one-way clutch is in bidirectional overrunning, and the drive motor outputs driving torque in the positive direction. When the two-speed transmission is in neutral, the multi-plate friction clutch is disengaged, the controllable one-way clutch is in bidirectional overrunning, and the drive motor does not output any torque. When the two-speed transmission is in first gear regenerative braking mode, the multi-plate friction clutch is disengaged, the controllable one-way clutch is in bidirectional lock-up, and the drive motor outputs electromagnetic braking torque in the positive direction. When the two-speed transmission is in second-gear regenerative braking mode, the multi-plate friction clutch is engaged, the controllable one-way clutch is in bidirectional overrunning mode, and the drive motor outputs electromagnetic braking torque in the positive direction; when the two-speed transmission is in reverse mode, the multi-plate friction clutch is disengaged, the controllable one-way clutch is in bidirectional lock-up mode, and the drive motor outputs driving torque in the opposite direction; when the two-speed transmission is in parking brake mode, the multi-plate friction clutch is engaged, the controllable one-way clutch is in bidirectional lock-up mode, and the drive motor does not output any torque.

9. A two-speed transmission for an electric vehicle using a dual planetary compound gear train as described in claim 8, characterized in that, The one-way lock-up state of the controllable one-way clutch refers to all transition states when the two-speed transmission switches between first-speed drive and second-speed drive, and when it switches between first-speed regenerative braking and second-speed regenerative braking.

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