Vehicle active steering transmission device with variable transmission ratio, and automobile

Abstract

The invention discloses a variable transmission ratio automobile active steering transmission device, comprising: a first planetary gear transmission mechanism and a second planetary gear transmission mechanism coaxially and symmetrically arranged, an assisting angle motor connected and arranged between the first planetary gear transmission mechanism and the second planetary gear transmission mechanism, a cylindrical inner gear ring coaxially arranged outside the first planetary gear transmission mechanism and the second planetary gear transmission mechanism and meshing with each planetary gear of each planetary gear transmission mechanism, an input shaft and an output shaft. The invention builds the assisting angle motor into the transmission device, reducing the space occupied by the entire transmission device; the motor directly drives the planet carrier to move, improving the transmission efficiency; the active steering is a deceleration and distance increasing transmission, the motor driving torque is small, the required motor power is small, thereby reducing the size of the mechanism and the required cost; when the control system fails, the mechanical steering system can still work normally, realizing failure backup, and having good safety.

Description

Technical Field

[0001] The invention relates to an automobile active steering system, in particular to an automobile active steering transmission device with a variable transmission ratio, which can improve the low-speed steering sensitivity of the vehicle, ensure the high-speed steering stability, and thus improve the vehicle's handling performance. Background Art

[0002] The automobile steering system is a series of devices that change or maintain the direction of the car according to the driver's wishes. It is crucial to the car's driving safety and handling stability.

[0003] The transmission ratio of most existing steering systems is not adjustable, that is, when the mechanical steering system is designed, the transmission ratio is fixed. With the increasing demand of drivers, such a fixed transmission ratio steering system has increasingly affected the user experience. An ideal steering system should be able to sense road conditions and vehicle speed, and then actively change the transmission ratio, that is, the transmission ratio is small at low speeds so that the steering is flexible, and the transmission ratio is large at high speeds so that the steering is smooth.

[0004] The active steering system adds a device to the steering system that can adjust the steering ratio according to the vehicle speed.

[0005] Figure 1 This is a simplified diagram of a specially processed variable pitch steering gear rack that is often used in the industry. The rack is dense in the middle and sparse on both sides, so that when turning in the middle area (high speed and small turning angle), the rack displacement is small, the transmission ratio is large, and the steering is relatively smooth; when turning in the two side areas (low speed and large turning angle), the rack displacement is large, the transmission ratio is small, and the steering is more flexible. The advantages of this method are: it is very simple in technology, and the effect of variable transmission ratio can be achieved by simply changing the pitch of the rack, without adding other devices, and the cost is low; the disadvantage is that the transmission ratio of the steering system changes directly with the steering wheel angle rather than the vehicle speed. In actual situations, it is not always a large turning angle at low speed and a small turning angle at high speed, and the transmission ratio only changes qualitatively indirectly with the vehicle speed, and fails to achieve accurate quantitative changes.

[0006] Figure 2It is the active steering system of BMW. The system disconnects the intermediate shaft between the steering wheel and the steering gear and adds a transmission device. The device mainly includes: input shaft 1, output shaft 11, two parallel planetary gear mechanisms, worm gears and auxiliary angle motor 7. Among them, the sun gear 2, planetary gear 3, planetary carrier 5 and inner gear ring 4 constitute planetary row I, and the sun gear 10, planetary gear 9, planetary carrier 5 and inner gear ring 8 constitute planetary row II. The two planetary rows share a planetary carrier 5, and the outer ring of the inner gear ring 8 is a worm gear. The inner gear ring 4 is fixed, and the transmission ratio of planetary row I and planetary row II is the same. One end of the input shaft 1 is connected to the steering wheel, and the other end is connected to the sun gear 2; one end of the output shaft 11 is connected to the sun gear 10, and the other end is connected to the input shaft of the steering gear. The working principle of the device is: when the steering wheel is turned, if the assisting angle motor does not work, the inner gear ring 8 does not rotate due to the self-locking function of the worm gear, and the transmission ratio between the input shaft and the output shaft is 1; if the control system detects the vehicle speed signal and controls the assisting angle motor to rotate, the inner gear ring 8 will be driven to rotate by the worm gear, and the transmission ratio changes at this time. The advantages of the device are: when the control part fails, the mechanical steering system can still work normally, and the failure backup can be realized, and the safety is good; after the control system detects the vehicle speed, the motor drives the inner gear ring to rotate, and the transmission ratio changes directly with the vehicle speed, and theoretically, it can have the best transmission ratio, and the effect is good. The disadvantages of the device are: the assisting angle motor and the worm gear are installed outside the device, occupying a certain space, and when the motor drives the worm 6 to rotate through the inner gear ring 8, the planetary gear 9, and the sun gear 10, the output is a speed-increasing torque-reducing transmission (the transmission ratio is less than 1), resulting in the motor having a larger driving torque, and the motor power and size are also larger, which increases the cost.

[0007] Figure 3 The invention is an active steering transmission device of the front wheel active steering system of the automobile described in patent CN102874300B. The active steering transmission device includes a mechanical transmission device and a power drive device. The mechanical transmission device is composed of two sets of parallel NGW type planetary gear transmission mechanisms; the sun gear 20, the planetary gear 15, and the inner ring gear 14 form a planetary row I; the sun gear 20, the planetary gear 17, and the inner ring gear 16 form a planetary row II, and the sun gear 20 is shared by the two planetary rows; the input shaft 12 is connected to one of the planetary carriers, and the output shaft 18 is connected to the second planetary carrier; the inner ring gear 16 is fixed, and the inner ring gear 14 is fixed to the worm wheel 19, and the motor drives the worm gear to drive the inner ring gear 15 to rotate. The advantages of this device are: it adopts mechanical connection, high safety, and the active steering output is driven by the power drive device to output the inner ring gear through the planetary carrier, which is a reduction transmission, and the driving torque of the motor and worm gear mechanism is small, thereby reducing the size of the mechanism, reducing costs, and reducing the space occupied; the disadvantages of this device are: the structure is relatively complicated, and the auxiliary angle motor and worm gear are installed outside the device, occupying a certain space. Summary of the invention

[0008] The purpose of the present invention is to overcome the problems existing in the existing active steering system transmission device and to provide a variable transmission ratio active steering transmission device with simple structure, small size, high efficiency, low cost and high safety.

[0009] The technical solution adopted by the present invention to solve its technical problem is:

[0010] An automobile active steering transmission device with a variable transmission ratio, comprising:

[0011] The first planetary gear transmission mechanism and the second planetary gear transmission mechanism are coaxially symmetrically arranged with a certain gap therebetween.

[0012] an assisting angle motor, connected and arranged between the first planetary gear transmission mechanism and the second planetary gear transmission mechanism;

[0013] The first planetary gear transmission mechanism comprises:

[0014] First sun gear;

[0015] A plurality of first planetary gears are evenly distributed and meshed with the first sun gear;

[0016] A first planet carrier, one end of which is fixedly connected to the housing of the assisting angle motor, and the other end of which is rotatably connected to the center holes of the first planetary wheels;

[0017] The second planetary gear transmission mechanism comprises:

[0018] Second sun gear;

[0019] A plurality of second planetary gears are evenly distributed and meshed with the second sun gear;

[0020] A second planet carrier, one end of which is drivingly connected to the output shaft of the assisting angle motor, and the other end of which is rotatably connected to the center holes of the second planetary gears;

[0021] A cylindrical inner gear ring, coaxially arranged outside the first planetary gear transmission mechanism and the second planetary gear transmission mechanism and meshing with the first planetary gear and the second planetary gear at the same time;

[0022] An input shaft and an output shaft, wherein one end of the input shaft is coaxially connected to the first sun gear, and the other end is connected to the input shaft of a steering wheel or a steering gear; one end of the output shaft is coaxially connected to the second sun gear, and the other end is connected to the input shaft of a steering wheel or a steering gear.

[0023] Furthermore, the first planetary gear transmission mechanism and the cylindrical inner gear ring form a planetary row I, and the second planetary gear transmission mechanism and the cylindrical inner gear ring form a planetary row II, and the transmission ratios of the planetary row I and the planetary row II are the same.

[0024] Furthermore, the first sun gear and the second sun gear have the same structural parameters, and the first planet gears and the second planet gears have the same structural parameters.

[0025] Furthermore, when the auxiliary angle motor is not working, it is in a self-locking state, the second planetary carrier does not rotate, and the transmission ratio of the transmission device is 1; when the auxiliary angle motor drives the second planetary carrier to rotate the second sun gear via the second planetary gear in the same direction as the first sun gear, the angle of rotation of the output shaft is greater than the angle of rotation of the input shaft, and the transmission ratio of the transmission device is less than 1; when the auxiliary angle motor drives the second planetary carrier to rotate the second sun gear via the second planetary carrier in an opposite direction to the first sun gear, the angle of rotation of the output shaft is greater than the angle of rotation of the input shaft, and the transmission ratio of the transmission device is less than 1.

[0026] Furthermore, the assist angle motor is controllably connected to a vehicle control system, and the vehicle control system determines a required transmission ratio of a vehicle steering system according to current road conditions and vehicle speed, and then controls the assist angle motor to work so as to achieve a target transmission ratio.

[0027] An automobile comprises a steering wheel and a steering gear, wherein an automobile active steering transmission device with a variable transmission ratio is arranged between the steering wheel and the steering gear.

[0028] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0029] The present invention integrates the assisting angle motor into the transmission device, thus reducing the space occupied by the entire transmission device;

[0030] When the assisting angle motor is working, it directly drives the planetary carrier to rotate and change the transmission ratio of the transmission device, eliminating the worm gear mechanism and improving the transmission efficiency.

[0031] Active steering is a motor-driven planetary carrier that outputs through the planetary gear and sun gear. It is a speed reduction and distance increase transmission. The motor driving torque is small and the required motor power is small, which can reduce the size of the mechanism and reduce the required cost.

[0032] When the control system fails, the mechanical steering system can still work normally, which can achieve failure backup and has good safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a simplified diagram of a variable pitch rack;

[0034] Figure 2This is a schematic diagram of the principle of BMW's automotive active steering system;

[0035] Figure 3 It is a schematic diagram of the principle of the active steering transmission device of the automobile active steering system described in patent CN102874300B;

[0036] Figure 4 It is a schematic diagram of the principle of a variable transmission ratio automobile active steering transmission device according to an embodiment of the present invention;

[0037] Figure 5 It is a schematic structural diagram of a vehicle active steering transmission device with a variable transmission ratio according to an embodiment of the present invention;

[0038] Figure 6 for Figure 5 Schematic diagram of the cross-sectional structure in the middle AA direction;

[0039] Explanation of the accompanying drawings: 1-input shaft, 2-the sun gear, 3-planetary gear, 4-inner ring gear, 5-planet carrier, 6-worm, 7-motor, 8-inner ring gear with worm gear as outer ring, 9-planetary gear, 10-the sun gear, 11-output shaft, 12-input shaft, 13-worm, 14-inner ring gear, 15-planetary gear, 16-inner ring gear, 17-planetary gear, 18-output shaft, 19-worm gear, 20-the sun gear, 21-input shaft, 22-first sun gear, 23-first planetary gear, 24-inner ring gear, 25-motor, 26-second planetary gear, 27-second sun gear, 28-output shaft, 29-first planet carrier, 30-second planet carrier. DETAILED DESCRIPTION

[0040] In order to better understand the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be noted that the specific implementation methods are not limitations of the protection scope of the present invention.

[0041] like Figures 4 to 6 As shown, a vehicle active steering transmission device with a variable transmission ratio comprises:

[0042] The first planetary gear transmission mechanism and the second planetary gear transmission mechanism are coaxially symmetrically arranged with a certain gap therebetween.

[0043] An assisting angle motor 25, connected and arranged between the first planetary gear transmission mechanism and the second planetary gear transmission mechanism;

[0044] The first planetary gear transmission mechanism comprises:

[0045] A first sun gear 22;

[0046] Three first planetary gears 23 are evenly distributed and mesh with the first sun gear 22;

[0047] A first planet carrier 29, one end of which is fixedly connected to the housing of the assisting angle motor 25, and the other end of which is rotatably connected to the center holes of the first planetary gears 23;

[0048] The second planetary gear transmission mechanism comprises:

[0049] Second sun gear 27;

[0050] Three second planetary gears 26 are evenly distributed and mesh with the second sun gear 27;

[0051] A second planet carrier 30, one end of which is drivingly connected to the output shaft of the assisting angle motor 25, and the other end of which is rotatably connected to the center holes of the second planetary gears 26;

[0052] The cylindrical inner gear ring 24 is coaxially arranged outside the first planetary gear transmission mechanism and the second planetary gear transmission mechanism and meshes with the first planetary gears 23 and the second planetary gears 26 at the same time.

[0053] An input shaft 21 and an output shaft 28, wherein one end of the input shaft 21 is coaxially connected to the first sun gear 22, and the other end is connected to the input shaft of the steering wheel or the steering gear; one end of the output shaft 28 is coaxially connected to the second sun gear 27, and the other end is connected to the input shaft of the steering wheel or the steering gear.

[0054] The first planetary gear transmission mechanism and the cylindrical inner gear ring 24 form a planetary gear row I, and the second planetary gear transmission mechanism and the cylindrical inner gear ring 24 form a planetary gear row II. The transmission ratios of the planetary gear row I and the planetary gear row II are the same.

[0055] The first sun gear 22 and the second sun gear 27 have the same structural parameters, and the first planetary gears 23 and the second planetary gears 26 have the same structural parameters.

[0056] When the auxiliary angle motor 25 is not working, it is in a self-locking state, the second planetary carrier 30 does not rotate, and the transmission ratio of the transmission device is 1; when the auxiliary angle motor 25 drives the second planetary carrier 30 to rotate the second sun gear 27 via the second planetary gear 26 in the same direction as the first sun gear 22, the rotation angle of the output shaft 28 is greater than the rotation angle of the input shaft 21, and the transmission ratio of the transmission device is less than 1; when the auxiliary angle motor 25 drives the second planetary carrier 30 to rotate the second sun gear 27 via the second planetary carrier 26 in the opposite direction to the rotation direction of the first sun gear 22, the rotation angle of the output shaft 28 is greater than the rotation angle of the input shaft 21, and the transmission ratio of the transmission device is less than 1.

[0057] The assist angle motor 25 is controllably connected to the vehicle control system, and the vehicle control system determines the required transmission ratio of the vehicle steering system according to the current road conditions and vehicle speed, and then controls the assist angle motor 25 to work to achieve the target transmission ratio.

[0058] When the steering wheel is rotated by an angle θ1, if the assisting angle motor 25 is not working, the output angle θ2 is equal to θ1 through the input shaft 21, the first sun gear 22, the first planetary gear 23, the inner ring 24, the second planetary gear 26 and the second sun gear 27 to the output shaft 28, and the transmission ratio of the transmission device is θ1 / θ2=1; if the assisting angle motor 25 is working, and the direction in which the second planetary carrier 30 is driven to rotate via the second planetary gear 26 to drive the second sun gear 27 is consistent with the input shaft 21, then the output shaft 28 angle θ2 is greater than θ1, and the transmission ratio θ1 / θ2<1 at this time; if the assisting angle motor 25 is working, and the direction in which the second planetary carrier 30 is driven to rotate via the second planetary gear 26 to drive the second sun gear 27 is opposite to the input shaft 21, then the output shaft 28 angle θ2 is greater than θ1, and the transmission ratio θ1 / θ2>1 at this time. It can be seen that in the actual process, the control system only needs to control the motor to drive the second planetary carrier 30 to rotate according to the vehicle speed signal, so as to change the transmission ratio of the transmission device, and then change the transmission ratio of the entire steering system, thereby meeting the driver's requirements for flexible low-speed steering and smooth high-speed steering of the vehicle, and improving the vehicle's maneuverability and comfort.

[0059] In the active steering transmission device, since the planetary row I and the planetary row II are symmetrical, the auxiliary steering motor 25 can either have a housing fixedly connected to the first planetary carrier 23 and a motor output shaft connected to the second planetary carrier 26, or a housing fixedly connected to the second planetary carrier 26 and a motor output shaft connected to the first planetary carrier 23, both of which can change the transmission ratio of the transmission device.

[0060] The auxiliary angle motor 25 is built into the transmission device, which reduces the space occupied by the entire transmission device; the auxiliary angle motor 25 directly drives the planetary carrier to move, eliminating the worm gear transmission mechanism and improving the transmission efficiency; active steering is that the auxiliary angle motor 25 drives the planetary carrier to output through the planetary gear and the sun gear, which is a speed reduction and distance increase transmission. The motor driving torque is small and the required motor power is small, thereby reducing the size of the mechanism and the required cost; when the control system fails, the mechanical steering system can still work normally, and failure backup can be achieved, which has good safety.

[0061] In summary, the transmission ratios of the planetary gears I and II in the above embodiment are the same. The auxiliary angle motor is built into the transmission device and is fixedly connected to the planetary carrier 3 and remains stationary. The motor output shaft is connected to the planetary carrier 10. When the motor is not working, it is in a self-locking state, and the planetary carrier 10 does not rotate. At this time, the transmission ratio of the transmission device is 1; when the motor is working, it drives the planetary carrier 10 to rotate, thereby changing the transmission ratio.

[0062] Another embodiment of the present invention provides an automobile, comprising a steering wheel and a steering gear, wherein an automobile active steering transmission device with a variable transmission ratio as described in the above embodiment is installed between the steering wheel and the steering gear.

[0063] The above embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A variable transmission ratio active steering transmission device for an automobile, characterized in that: include: The first planetary gear transmission mechanism and the second planetary gear transmission mechanism are coaxially symmetrically arranged with a certain gap therebetween. an assisting angle motor (25), connected and arranged between the first planetary gear transmission mechanism and the second planetary gear transmission mechanism; The first planetary gear transmission mechanism comprises: A first sun gear (22); A plurality of first planetary gears (23) are evenly distributed and meshed with the first sun gear (22); A first planet carrier (29), one end of which is fixedly connected to the housing of the assisting angle motor (25), and the other end of which is rotatably connected to the center holes of the first planetary gears (23); The second planetary gear transmission mechanism comprises: A second sun gear (27); A plurality of second planetary gears (26) are evenly distributed and mesh with the second sun gear (27); A second planetary carrier (30), one end of which is drivingly connected to the output shaft of the assisting angle motor (25), and the other end of which is rotatably connected to the center holes of the second planetary gears (26); A cylindrical inner gear ring (24) is coaxially arranged outside the first planetary gear transmission mechanism and the second planetary gear transmission mechanism and is meshed with each of the first planetary gear (23) and the second planetary gear (26); An input shaft (21) and an output shaft (28), wherein one end of the input shaft (21) is coaxially connected to the first sun gear (22), and the other end is connected to the input shaft of the steering wheel; one end of the output shaft (28) is coaxially connected to the second sun gear (27), and the other end is connected to the input shaft of the steering gear; The first planetary gear transmission mechanism and the cylindrical inner gear ring (24) form a planetary gear row I, and the second planetary gear transmission mechanism and the cylindrical inner gear ring (24) form a planetary gear row II, and the transmission ratios of the planetary gear row I and the planetary gear row II are the same; The first sun gear (22) and the second sun gear (27) have the same structural parameters, and the first planetary gears (23) and the second planetary gears (26) have the same structural parameters.

2. The variable transmission ratio active steering transmission device for an automobile according to claim 1, characterized in that: When the assisting angle motor (25) is not working, it is in a self-locking state, the second planetary carrier (30) does not rotate, and the transmission ratio of the transmission device is 1; when the assisting angle motor (25) drives the second planetary carrier (30) to rotate the second sun gear (27) via the second planetary gear (26) in the same direction as the first sun gear (22), the rotation angle of the output shaft (28) is greater than the rotation angle of the input shaft (21), and the transmission ratio of the transmission device is less than 1; when the assisting angle motor (25) drives the second planetary carrier (30) to rotate the second sun gear (27) via the second planetary gear (26) in the opposite direction to the first sun gear (22), the rotation angle of the output shaft (28) is less than the rotation angle of the input shaft (21), and the transmission ratio of the transmission device is greater than 1.

3. The variable transmission ratio active steering transmission device for automobile according to claim 1, characterized in that: The assisting turning angle motor (25) is controllably connected to a vehicle control system, and the vehicle control system determines the required transmission ratio of the vehicle steering system according to current road conditions and vehicle speed, and then controls the assisting turning angle motor (25) to work so as to achieve a target transmission ratio.

4. A car, comprising a steering wheel and a steering gear, characterized in that: An automobile active steering transmission device with a variable transmission ratio as described in any one of claims 1 to 3 is installed between the steering wheel and the steering gear.

Images