Torque feedback device

Abstract

The invention relates to a torque feedback device. The torque feedback device is used for providing feedback torque for a steering wheel of the drive-by-wire vehicle and comprises an execution motor and a speed reducer, the execution motor outputs the feedback torque to the steering wheel through the speed reducer, and the speed reducer is a harmonic gear speed reducer. The torque feedback device provided by the invention has an improved structure.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular to a torque feedback device for a steering wheel of a wire-controlled vehicle. Background Art

[0002] In the steering system of traditional vehicles, a mechanical connection needs to be set between the steering wheel and the wheel. The mechanical connection can transfer the reaction torque on the wheel to the steering wheel, making it easier for the driver to control the vehicle. However, in the steering systems of some new vehicles, the steering wheel is mechanically decoupled from the wheel. In this case, the system detects the rotation position of the steering wheel through a sensor, and sends instructions to the actuator that drives the wheel steering according to the rotation position, thereby controlling the steering angle of the wheel. This type of vehicle is called a wire-controlled vehicle. In a wire-controlled vehicle, the system also detects the reaction torque of the wheel, and sends instructions to the torque feedback device of the steering wheel according to the reaction torque, so that the torque feedback device generates a corresponding feedback torque on the steering wheel, so that the driver can perceive the reaction torque as realistic as possible through the steering wheel.

[0003] Torque feedback devices usually provide feedback torque through motors. Since the output torque of conventional motors usually has a high speed, a reducer needs to be set between the motor and the steering wheel to change the speed of the output torque. In some existing torque feedback devices, the reducer is implemented by a worm gear mechanism. The worm gear mechanism requires a large installation space, which is obviously not conducive to the layout design of the wire control system. Other torque feedback devices use planetary gear reducers. However, the gear clearance of planetary gear reducers is large, which may cause noise problems and affect the driving experience. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide an improved torque feedback device.

[0005] The above technical problems are solved by a torque feedback device according to the present invention. The torque feedback device is used to provide feedback torque for the steering wheel of a wire-controlled vehicle. The torque feedback device includes an actuator motor and a reducer, and the actuator motor outputs feedback torque to the steering wheel via the reducer. The reducer is a harmonic gear reducer. The harmonic gear reducer has a more compact layout and can reduce the size of the torque feedback device. At the same time, the gear clearance of the harmonic gear reducer is small, which can reduce noise.

[0006] According to a preferred embodiment of the present invention, the torque feedback device may further include a controller, which calculates the feedback torque according to the driving parameters of the wire-controlled vehicle and controls the actuator motor to generate the feedback torque. The controller of the torque feedback device is integrated with the reducer and the actuator motor, which can effectively reduce the layout space required for the torque feedback device.

[0007] According to another preferred embodiment of the present invention, the torque feedback device may further include a housing, in which the controller, the actuator motor and the harmonic gear reducer are mounted, so that the controller, the actuator motor and the harmonic gear reducer of the torque feedback device can be integrated and packaged together via the housing.

[0008] According to another preferred embodiment of the present invention, the harmonic gear reducer and the actuator motor can be arranged around a common rotation axis, and the rotation axes of the harmonic gear reducer and the actuator motor are arranged to coincide with the rotation axis of the steering wheel, thereby facilitating the connection between the reducer and the actuator motor and enabling the layout of the torque feedback device to be more compact.

[0009] According to another preferred embodiment of the present invention, the controller, the actuator motor and the harmonic gear reducer can be arranged in sequence in the housing along the axial direction, thereby achieving a simple and compact layout of the internal structure of the housing.

[0010] According to another preferred embodiment of the present invention, the housing may include a housing body, a motor cover, and a controller cover, the actuator motor and the harmonic gear reducer are encapsulated by the housing body and the motor cover, and the controller is encapsulated by the motor cover and the controller cover. The actuator motor and the reducer are separated from the controller by the motor cover, which is beneficial to prevent the lubricating fluid and dust in the installation space of the transmission mechanism from contaminating the circuit board of the controller.

[0011] According to another preferred embodiment of the present invention, the torque feedback device may further include a sensor for detecting the rotational position of the steering wheel, the sensor being arranged on the output end and / or the housing of the harmonic gear reducer. The sensor may thus be integrated inside the housing.

[0012] According to another preferred embodiment of the present invention, the torque feedback device may further include a stop structure for limiting the rotation range of the steering wheel, the stop structure being arranged between the output end of the harmonic gear reducer and the housing. The stop structure may prevent the steering wheel from rotating excessively.

[0013] According to another preferred embodiment of the present invention, the controller can be configured to control the execution motor to return the steering wheel to the center position when the steering wheel is not subjected to the driver's operating force. Thus, the automatic return function of the steering wheel can be realized by the controller.

[0014] According to another preferred embodiment of the present invention, the actuator motor may be a brushless DC motor. The brushless DC motor has a simple structure and low cost, and can reduce the cost of the torque feedback device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below in conjunction with the accompanying drawings. The same reference numerals in the drawings represent elements with the same functions.

[0016] Figure 1An exploded view of a torque feedback device according to an exemplary embodiment of the present invention is shown;

[0017] Figure 2 A perspective view showing a torque feedback device according to an exemplary embodiment of the present invention;

[0018] Figure 3 A cross-sectional view showing a torque feedback device according to an exemplary embodiment of the present invention; and

[0019] Figure 4 A schematic diagram illustrating a harmonic gear reducer of a torque feedback device according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following detailed description and drawings are used to exemplarily illustrate the principles of the present invention. The present invention is not limited to the preferred embodiments described, and the protection scope of the present invention is defined by the claims.

[0021] According to an embodiment of the present invention, a torque feedback device for a wire-controlled vehicle is provided. The torque feedback device is used to be installed together with a steering wheel of the wire-controlled vehicle so as to provide feedback torque to the steering wheel when the driver manipulates the steering wheel.

[0022] Figures 1 to 4 An exemplary embodiment of a torque feedback device according to the present invention is shown. Figure 1 and Figure 2 The exploded view and stereogram of the torque feedback device are shown respectively. Figure 1 and Figure 2 As shown, the torque feedback device is installed together with the steering wheel 10 of the wire-controlled vehicle. The steering wheel 10 and the torque feedback device are applied to the wire-controlled vehicle, that is, there is no mechanical connection between the steering wheel 10 and the wheels of the vehicle. In this case, the torque feedback device provides feedback torque to the steering wheel 10 to ensure the driving experience of the driver.

[0023] The torque feedback device includes an actuator motor 20 and a reducer. In the present invention, the reducer used in the torque feedback device is a harmonic gear reducer 30. The actuator motor 20 can output feedback torque for the steering wheel 10. The harmonic gear reducer 30 is connected between the output shaft of the actuator motor 20 and the input shaft of the steering wheel 10, so that the actuator motor 20 can output feedback torque to the steering wheel 10 via the harmonic gear reducer 30. The harmonic gear reducer 30 has a predetermined transmission ratio, so that the rotation speed of the output torque of the actuator motor 20 changes (especially decreases) after passing through the harmonic gear reducer 30, so as to be adjusted to a rotation speed adapted to the operating rotation speed of the steering wheel 20.

[0024] In a wire-controlled vehicle, the steering wheel 10 is mechanically decoupled from the wheels, and the actuator motor 20 is required to generate feedback torque corresponding to the vehicle's driving state. The actuator motor 20 is preferably a brushless DC motor. This motor has a simple structure and is easy to maintain, has a high service life and control accuracy, and can effectively save layout space and production costs. Alternatively, the actuator motor 20 can also be other various known types of motors, as long as it can provide feedback torque for the steering wheel 10.

[0025] The harmonic gear reducer 30 may be any harmonic gear reducer known in the prior art. Figure 4 FIG. 2 shows a schematic diagram of a harmonic gear reducer 30 according to an embodiment of the present invention. Figure 4 As shown, the basic structure and working principle of a conventional harmonic gear reducer 30 are explained by taking an elliptical spherical bearing harmonic gear reducer as an example. The harmonic gear reducer 30 mainly includes a coaxially arranged harmonic generator 31, a flexible wheel 32 and a rigid wheel 33. In the present embodiment, the harmonic generator 31 is schematically shown as an elliptical spherical bearing harmonic generator, but this is not restrictive, and other types of harmonic generators can also be used. The flexible wheel 32 surrounds the radial outer side of the elliptical outer ring of the harmonic generator 31. The flexible wheel 32 is made of a flexible material, which can be deformed as the harmonic generator 31 rotates. The rigid wheel 33 surrounds the radial outer side of the flexible wheel 32, which is made of a rigid material. The flexible wheel 32 has external teeth, and the rigid wheel 33 has internal teeth corresponding to the external teeth of the flexible wheel 32. The external teeth of the flexible wheel 32 can only mesh with the internal teeth of the rigid wheel 33 in the area radially elongated as the harmonic generator 31 rotates. The meshing area between the flexible wheel 32 and the rigid wheel 33 thus gradually moves in the circumferential direction as the harmonic generator 31 rotates, and the rigid wheel 33 is driven to rotate at a speed much lower than the input speed of the harmonic generator 31. Therefore, the torque with a reduced speed can be output via the rigid wheel 33. In order to facilitate the output of torque from the rigid wheel 33, the harmonic gear reducer 30 may further include an output shaft 34 coaxially fixedly connected to the rigid wheel 33, and the output shaft 34 is axially located on the side of the rigid wheel 33 facing the steering wheel 10.

[0026] Figure 3 FIG. 4 shows a cross-sectional view of the torque feedback device through the central axis. Figure 3 As shown, the actuator motor 20 and the harmonic gear reducer 30 can preferably be arranged around a common rotation axis, which is the central axis of the actuator motor 20 and the harmonic gear reducer 30. When the torque feedback device is installed with the steering wheel 10, the rotation axis of the steering wheel 10 is also arranged to coincide with the rotation axis of the actuator motor 20 and the harmonic gear reducer 30. In the axial direction, the harmonic gear reducer 30 is closer to the steering wheel 10 than the actuator motor 20.

[0027] The torque feedback device also includes a controller 40 for controlling the operation of the actuator motor 20. The controller 40 is, for example, an integrated circuit control component commonly used in the prior art. Since the steering wheel 10 and the actuator motor 20 are both mechanically decoupled from the wheels, when the driver operates the steering wheel, the controller 40 needs to first obtain the driving parameters of the vehicle's driving system, especially the wheels and other components, and then calculate the required feedback torque based on the driving parameters, and finally issue corresponding control instructions to the actuator motor 20 so that the actuator motor 20 generates the corresponding feedback torque. The controller 40 needs to communicate with the controller (external controller) that controls the driving system, especially the wheels (for example, via a CAN bus), and needs to communicate with the actuator motor 20. The driving parameters obtained by the controller 40 from the external controller for calculating the feedback torque may include the wheel speed and friction of the wheel. In terms of spatial layout, the controller 40 is integrated and assembled with the actuator motor 20 and the harmonic gear reducer 30 as part of the torque feedback device, and is separated from the wheels and the external controller in space. The control function of the controller 40 can be realized by the software stored therein.

[0028] Preferably, a steering wheel return function may be integrated into the software of the controller 40. Specifically, the controller 40 may be configured to control the actuator motor 20 to drive the steering wheel 10 to actively rotate back to the initial position (neutral position) when the steering wheel 10 is not subjected to the driver's operating force, that is, to return the steering wheel 10 to the center.

[0029] In order to facilitate integration of the actuator motor 20, the harmonic gear reducer 30 and the controller 40 of the torque feedback device, the torque feedback device may further include a housing 50. Figure 3 As shown, the actuator motor 20, the harmonic gear reducer 30 and the controller 40 are respectively installed in the housing 50 to form a complete device. Preferably, the harmonic gear reducer 30 and the actuator motor 20 are coaxially arranged in the housing 50, and the controller 40, the actuator motor 20 and the harmonic gear reducer 30 are arranged in sequence along the axial direction in the housing 50, wherein the harmonic gear reducer 30 is closest to the steering wheel 10 in the axial direction.

[0030] The housing 50 may be composed of multiple parts so that different components can be installed separately. Figure 3As shown, the housing 50 may include a housing body 51, a motor cover 52 and a controller cover 53. The actuator motor 20 and the harmonic gear reducer 30 are encapsulated by the housing body 51 and the motor cover 52. The housing body 51 is formed as a substantially cylindrical component, and the actuator motor 20 and the harmonic gear reducer 30 are accommodated in the radial inner side of the housing body 51. The motor cover 52 is closed and fixed to the axial end of the housing body 51 away from the steering wheel 10. In the housing body 51, the actuator motor 20 is closer to the motor cover 52 than the harmonic gear reducer 30. The rigid wheel 33 of the harmonic gear reducer 30 is rotatably mounted at the other axial end of the housing body 51, and the output shaft 34 of the harmonic gear reducer 30 extends axially out of the housing body 51 in a direction away from the motor cover 52 so as to connect the steering wheel 10. The controller 40 is encapsulated by the motor cover 52 and the controller cover 53. The motor cover 52 forms a substantially cylindrical cavity on the side facing away from the housing body 51 to accommodate the controller 40. The controller cover 53 is fixed to the axial end of the motor cover 52 facing away from the housing body 51, thereby closing the cavity accommodating the controller 40. The space accommodating the actuator motor 20 and the harmonic gear reducer 30 is separated from the space accommodating the controller 40 by the motor cover 52.

[0031] The torque feedback device may also include a sensor (not shown) for detecting the rotational position (rotational angle) of the steering wheel 10. The sensor may be integrated inside the housing 50. For example, the sensor may be arranged at the output end (particularly the rigid wheel 33) of the harmonic gear reducer 30 and / or at a position of the housing 50 corresponding to the output end of the harmonic gear reducer 30, so as to detect the rotational position of the output end of the harmonic gear reducer 30. Since the output end of the harmonic gear reducer 30 is torsionally connected to the steering wheel 10, the rotational position of the output end of the harmonic gear reducer 30 is the rotational position of the steering wheel 10. The sensor used may be any type of sensor known in the prior art, such as a Hall sensor, as long as it can detect the rotational position of the steering wheel 10. The rotational position of the steering wheel 10 detected by the sensor may be provided to an external controller that controls the travel system, particularly the wheels, through a communication connection (wired or wireless), so as to convert the driver's operation of the steering wheel 10 into directional control of the travel system.

[0032] Preferably, the torque feedback device may further include a stop structure (not shown) for limiting the rotation range of the steering wheel 10. Similarly, the stop structure may also be integrated inside the housing 50, for example, it may be arranged between the output end of the harmonic gear reducer 30 and the housing 50. For example, the stop structure may be arranged on the radial outer side of the rigid wheel 33 of the harmonic gear reducer 30 and / or on the radial inner side of the housing 50 (particularly the housing body 51). Such a stop structure may be, for example, a protrusion extending from the radial outer side of the rigid wheel 33 and / or a protrusion extending from the radial inner side of the housing 50, which can stop the rigid wheel 33 when the rigid wheel 33 rotates to a predetermined limit position along with the steering wheel 10, thereby preventing the rigid wheel 33 and the steering wheel 10 from further rotating relative to the housing 50 beyond the predetermined rotation range.

[0033] The torque feedback device according to the present invention uses a harmonic gear transmission as a transmission mechanism between the actuator motor and the steering wheel. The harmonic gear reducer has a high transmission ratio and occupies a small space, which can effectively save space. At the same time, the harmonic gear reducer has a small gear gap and generates little noise, thereby providing excellent NVH performance. In addition, the controller that controls the actuator motor of the torque feedback device is also integrated with the harmonic gear reducer and the actuator motor, thereby achieving a more compact space layout.

[0034] Although possible embodiments are described by way of example in the above description, it should be understood that there are still a large number of variations of embodiments through the combination of all known and other technical features and embodiments that are easily conceivable to the skilled person. It should also be understood that the exemplary embodiment is only an example and that such an embodiment in no way limits the scope of protection, application and configuration of the present invention. The above description is more to provide the skilled person with a technical guide for converting at least one exemplary embodiment, wherein various changes can be made, especially changes in the functions and structures of the components, as long as they do not depart from the scope of protection of the claims.

[0035] Reference numerals list

[0036] 10. Steering Wheel

[0037] 20 Actuator motor

[0038] 30 Harmonic gear reducer

[0039] 31 Harmonic Generator

[0040] 32 Flexspline

[0041] 33 Steel Wheel

[0042] 34 Output shaft

[0043] 40 Controller

[0044] 50 Shell

[0045] 51 Shell body

[0046] 52 Motor cover

[0047] 53 Controller cover

Claims

1. A torque feedback device for providing feedback torque to a steering wheel (10) of a controlled-by-wire vehicle, the torque feedback device comprising an actuator motor (20) and a reducer, the actuator motor (20) outputting the feedback torque to the steering wheel (10) via the reducer, It is characterized in that The reducer is a harmonic gear reducer (30).

2. The torque feedback device according to claim 1, characterized in that: The torque feedback device further comprises a controller (40), wherein the controller (40) calculates the feedback torque according to the driving parameters of the controlled-by-wire vehicle and controls the actuator motor (20) to generate the feedback torque.

3. The torque feedback device according to claim 2, characterized in that: The torque feedback device further comprises a housing (50), in which the controller (40), the actuator motor (20) and the harmonic gear reducer (30) are installed.

4. The torque feedback device according to claim 3, characterized in that: The harmonic gear reducer (30) and the actuator motor (20) are arranged around a common rotation axis, and the rotation axes of the harmonic gear reducer (30) and the actuator motor (20) are arranged to coincide with the rotation axis of the steering wheel (10).

5. The torque feedback device according to claim 4, characterized in that: The controller (40), the actuator motor (20) and the harmonic gear reducer (30) are sequentially arranged in the axial direction in the housing (50).

6. The torque feedback device according to claim 5, characterized in that: The housing (50) comprises a housing body (51), a motor cover (52) and a controller cover (53); the actuator motor (20) and the harmonic gear reducer (30) are encapsulated by the housing body (51) and the motor cover (52); and the controller (40) is encapsulated by the motor cover (52) and the controller cover (53).

7. The torque feedback device according to claim 3, characterized in that: The torque feedback device further comprises a sensor for detecting the rotational position of the steering wheel (10), wherein the sensor is arranged on the output end of the harmonic gear reducer (30) and / or the housing (50).

8. The torque feedback device according to claim 3, characterized in that: The torque feedback device further comprises a stop structure for limiting the rotation range of the steering wheel (10), wherein the stop structure is arranged between the output end of the harmonic gear reducer (30) and the housing (50).

9. The torque feedback device according to claim 2, characterized in that: The controller (40) is configured to control the actuator motor (20) to correct the steering wheel (10) when the steering wheel (10) is not subjected to a driver's operating force.

10. The torque feedback device according to any one of claims 1 to 9, characterized in that: The actuator motor (20) is a brushless DC motor.

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