Steering actuator for increasing steering speed

Abstract

The invention relates to a steering gear, in particular to a steering actuator for increasing the steering speed. The steering gear comprises a shell, a rack, a ball head pull rod and steering execution mechanisms, the two ends of the shell are respectively provided with the steering execution mechanisms, and each steering execution mechanism comprises a main controller, a driving motor, a worm and worm wheel and a gear shaft. A steering wheel of the steering actuator is decoupled from a steering gear, steering can be faster, in-situ full-angle steering only needs one second, and the steering actuator can rapidly turn around in situ; meanwhile, faster steering can be achieved without being limited by rotation of a steering wheel, and therefore the requirement for the steering speed can be met. The problems that an existing steering gear is low in steering speed and cannot meet the automatic driving requirement are solved.

Description

Technical Field

[0001] The invention relates to a steering actuator, in particular to a steering actuator capable of enhancing steering speed. Background Art

[0002] The traditional steering gear (steering actuator) includes a housing, an input shaft, a rack and a ball rod, wherein the top end of the input shaft is connected to the steering wheel through an intermediate shaft and a steering column; the bottom end of the input shaft is connected to the gear shaft through a torsion bar, and the gear shaft meshes with the rack. The steering wheel can drive the rack to move axially through the steering column, intermediate shaft, input shaft, torsion bar, and gear shaft in sequence, thereby pulling the ball rod to move, thereby pulling the wheel connected to the ball rod to deflect and complete the steering. Due to the large friction between the tire and the ground, it is difficult to turn the steering wheel. Generally, an electric motor or hydraulic power assist is required to reduce steering resistance and improve driving feel. During the steering process, it is necessary to detect the rotation angle of the gear shaft when assisting, so as to feedback and adjust the power motor to ensure the accuracy of the steering. At present, the detection of the gear shaft is to detect the torque angle between the torsion bar and the gear shaft and the input shaft through a torque angle signal sensor, and then indirectly detect the rotation of the gear shaft (see Figure 3 ).

[0003] The above-mentioned traditional steering gear also has the following defects: since the steering wheel is connected to the gear shaft through the steering column, the intermediate shaft, the input shaft, and the torsion bar in sequence, the steering wheel and the gear shaft are in a strong connection state, so the gear shaft can only rotate when the steering wheel is turned; since the rotation of the steering wheel is easily affected by the driver's manual intervention and the driver's reaction speed, the steering wheel turns slowly, and the steering wheel rotation speed affects the gear shaft rotation speed, resulting in the gear shaft being unable to rotate quickly, which greatly affects the transmission between the steering wheel and the gear shaft, thereby affecting the steering speed, making it difficult to meet the steering speed requirements for autonomous driving or assisted driving above L3 level.

[0004] In addition, in the prior art, connecting teeth are respectively provided at both ends of the rack, and the connecting teeth at one end of the rack are connected to the gear shaft of the motor-assisted steering assistance, and the connecting teeth at the other end of the rack are connected to the gear shaft of the mechanical assistance, and the gear shaft of the mechanical assistance is connected to the steering wheel through a torsion bar, an input shaft, an intermediate shaft and a steering column. For example, a double-input shaft electric power steering device and a car disclosed in the patent application with the announcement number CN209650364U. It can speed up the steering speed through multiple assistance. However, since one end of the above-mentioned steering gear rack is mechanically assisted and the other end of the rack is motor-assisted, the mechanical assistance and the motor assistance on the rack are not completely the same, which will cause the rack to be unbalanced. The solution is to change the phase angle of the connecting teeth at both ends of the rack, change the force at both ends of the rack, so that the circumferential forces at both ends of the rack offset each other partially, thereby reducing the flipping of the rack and making it difficult for the circumferential force to affect the movement of the rack. However, the circumferential forces at both ends of the rack cannot be completely offset, and will still affect the movement speed of the rack.

[0005] Therefore, it is necessary to design a steering actuator that enhances the steering speed to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a steering actuator which can flexibly and quickly turn and enhance the steering speed in view of the shortcomings of the prior art.

[0007] The technical solution of the present invention is: A steering actuator for enhancing steering speed, comprising a housing, a rack, a ball head tie rod and a steering actuator, wherein a rack is mounted on the housing through a support seat, and ball head tie rods are respectively arranged at both ends of the rack. The invention is characterized in that steering actuators are respectively arranged at both end ends of the housing, and the steering actuator comprises a main controller connected to a steering wheel control central line, a drive motor, a worm gear and a gear shaft, the drive motor is electrically connected to the main controller, the output shaft of the drive motor is connected to the gear shaft through a worm gear, and the gear shaft is meshed with the rack.

[0008] The gear shafts are respectively provided with single-axis angle signal sensors for detecting the rotation angle of the gear shafts, and the single-axis angle signal sensors are electrically connected to the main controller.

[0009] Preferably, the main controller is connected to the steering wheel control center via a CAN bus.

[0010] The contact angle between the rack and the support seat is 15°-33°.

[0011] Preferably, the contact angle between the rack and the support seat is 30°.

[0012] One end of the rack is provided with a connecting tooth A, and the other end of the rack is provided with a connecting tooth B. The connecting tooth A and the connecting tooth B are respectively connected to the gear shafts at the ends of the shell; the phase angles of the connecting tooth A and the connecting tooth B are the same.

[0013] The beneficial effects of the present invention are: The steering wheel of the steering actuator with enhanced steering speed is decoupled from the steering gear, which can achieve a flexible transmission ratio. The steering wheel angle can be fully rotated by 150°, so that the driver does not need to cross his hands when driving the vehicle to fully turn the direction, which is more convenient for parking and entering the garage, and the steering wheel turns more quickly; because the steering wheel rotation angle is reduced, and the drive motor can rotate faster without restriction, it can turn faster, and it only takes 1s to turn at full angle on the spot, so that it can quickly turn around on the spot; at the same time, the steering wheel is decoupled from the steering gear, and the steering gear can work without being restricted by the steering wheel rotation, and can turn faster, so as to meet the steering speed requirements of automatic driving or L3 or above assisted driving. In addition, steering and steering assistance are carried out through multiple steering actuators, and the torque can be evenly distributed through multiple steering actuators, which can effectively reduce the torque borne by a single steering actuator while ensuring the output of a large total torque, thereby effectively reducing the size of a single steering actuator; at the same time, the intermediate shaft, input shaft and torsion bar are eliminated, so that the steering gear is decoupled from the steering wheel, further reducing the space occupied in the cabin, and making the cabin and chassis layout more flexible. The problem that the existing steering gear has slow steering speed and is difficult to meet the requirements of automatic driving is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the installation of the single-axis angle signal sensor of the present invention; Figure 3 It is a schematic diagram of the arrangement of sensors in the prior art; Figure 4 is a schematic diagram of the contact angle (15°) of the present invention; Figure 5 is a schematic diagram of the contact angle (30°) of the present invention; Figure 6 is a schematic diagram of the contact angle (33°) of the present invention; Figure 7 It is a schematic diagram of the structure of a rack in the prior art; Figure 8 It is a schematic diagram of the structure of the rack of the present invention; Fig. 9 It is the statistical diagram of the wear amount of the present invention; Fig.10 It is a force statistical diagram of the rack of the present invention; Fig.11 It is a force statistical diagram of the rack in the prior art.

[0015] In the figure: 1. housing, 2. rack, 3. ball head pull rod, 4. support seat, 5. main controller, 6. drive motor, 7. gear shaft, 8. single-axis angle signal sensor, 9. connecting tooth A, 10. connecting tooth B, 11. input shaft, 12. torsion bar, 13. torque angle signal sensor, 14. worm wheel, 15. worm. DETAILED DESCRIPTION

[0016] The steering actuator for enhancing steering speed comprises a housing 1, a rack 2, a ball tie rod 3 and a steering actuator. The housing 1 is provided with a rack 2, and both ends of the rack 2 are supported by support seats 4 provided on the housing 1. Both ends of the rack 2 are provided with ball tie rods 3, and the ball tie rods 3 are connected to wheels. Steering actuators are provided at both ends of the housing 1. When a single power-assisting mechanism is driven, the force-bearing area must be increased to ensure durability, thereby reducing pressure. The steering actuators provided at both ends of the housing 1 cooperate to drive the rack 2, and the torque required to drive the rack 2 is shared by multiple steering actuators, thereby reducing pressure by reducing torque, and reducing the torque required to be provided by a single steering actuator, thereby effectively reducing the volume occupied by a single steering actuator.

[0017] The steering actuator includes a main controller 5, a drive motor 6, a worm gear and a gear shaft 7. The drive motor 6 is electrically connected to the main controller 5 so as to control the start, stop and rotation of the drive motor 6 through the main controller 5, wherein the rotation of the drive motor 6 includes the rotation angle, rotation torque and rotation speed of the output shaft of the drive motor 6. A worm 15 is connected to the output shaft of the drive motor 6, a worm gear 14 is connected to the worm 15, a gear shaft 7 is inserted at the end face center of the worm gear 14, and the gear shaft 7 is meshed with the rack 2. The function of the worm 15 is to drive the worm gear 14 to rotate through the rotating worm 15 when the drive motor 6 drives the worm 15 to rotate, and then drive the gear shaft 7 to rotate through the rotating worm gear 14, thereby driving the rack 2 to move through the rotating gear shaft 7.

[0018] The main controller 5 is connected to the steering wheel control center line. The steering wheel control center can detect the rotation of the steering wheel, and it converts the rotation signal of the steering wheel into a digital signal and transmits it to the main controller 5. The main controller 5 controls the drive motor 6 to rotate according to the rotation signal of the steering wheel, thereby steering. Since the steering wheel is connected to the steering gear line, the steering wheel can be decoupled from the steering gear, and then the intermediate shaft between the steering wheel and the steering gear can be discarded, thereby further reducing the space occupation, so that the cabin and the chassis can be flexibly arranged. During the driving process of the vehicle, the drive motor 6 can also detect the reaction force of the road surface transmitted to the drive motor 6 in sequence through the wheel, the ball head tie rod 3, the rack 2, the gear shaft 7, and the worm gear, and then detect the road surface information. The drive motor 6 transmits the road surface signal to the steering wheel control center through the main controller 5, so that the steering wheel control center can control the rotation damping of the steering wheel according to the road surface information, thereby transmitting road sense information to the driver.

[0019] In the prior art, an output shaft is mounted on the gear shaft 7, a torsion bar is arranged between the output shaft and the gear shaft, and a torque angle signal sensor is arranged at the bottom end of the output shaft. The torque angle signal sensor detects the change of the torque angle, detects the change or change trend of the torque between the gear shaft and the output shaft, and thus detects the rotation angle of the gear shaft; the torque angle signal sensor can only be used to detect the output shaft and the torsion bar (see Figure 3 ).

[0020] In the present application, the gear shafts 7 of the steering actuators at both ends of the housing 1 are respectively provided with single-axis angle signal sensors 8 (such as HELLA 6PD 312.472-71 type) for detecting the rotation angle of the gear shaft 7, and the single-axis angle signal sensor 8 is electrically connected to the main controller 5. The function of the single-axis angle signal sensor 8 is to detect the rotation angle of the gear shaft 7 through the single-axis angle signal sensor 8, and then transmit the rotation angle signal of the gear shaft 7 to the main controller 5, so that the main controller 5 can feedback and adjust the rotation of the gear shaft 7 according to the rotation angle of the gear shaft 7, to ensure that the gear shaft 7 rotates in place, that is, to ensure that the steering is in place. Since the detection is performed by the single-axis angle signal sensor 8, the single-axis angle signal sensor 8 does not need the cooperation of the output shaft and the torsion bar, that is, it can detect the rotation of the gear shaft 7, thereby saving the space occupied by the output shaft and the torsion bar.

[0021] Preferably, the main controller 5 is connected to the steering wheel control center via a CAN bus. The CAN bus uses non-destructive arbitration technology. When two nodes transmit data to the network at the same time, the node with a low priority actively stops sending data, while the node with a high priority can continue to transmit data without being affected, effectively avoiding bus conflicts. Then, through the CAN bus, the main controllers 5 at both ends of the shell 1 control the drive motor 6 to operate in coordination, so that the rotation of the drive motor 6 is not prone to conflict. The CAN bus can transmit and receive data in a one-to-many and broadcast centralized manner, and can ensure data transmission between the main controllers 5 at both ends of the shell 1 and the steering wheel control center, ensuring that the steering wheel control center can drive the main controllers 5 at both ends of the shell 1 respectively, and can receive the road sense information transmitted by the main controllers 5 at both ends of the shell 1 respectively.

[0022] The contact angle between the rack 2 and the support seat 4 is 15°-33°. Preferably, the contact angle between the rack 2 and the support seat 4 is 30°.

[0023] A comparative experiment was conducted with the contact angle less than 15° (such as 13°) and the contact angle of 30° as variables. The other conditions of the experiment were the same, that is, the rack movement speed was 10mm / s, the load on the rack was 2000N, the rack stroke was ±72mm, the number of cycles was 100,000 times, the lubrication condition was grease coating, the maximum operating temperature was 80°C, and the rack surface roughness was Ra0.2. The rack diameters were counted before and after the experiment, and the rack wear was counted by the difference in rack diameters, and a bar graph of the wear statistics was drawn (see Fig. 9 ).

[0024] It is not difficult to see from the bar graph of the wear statistics that the wear of the rack when the contact angle between the rack and the support seat is 30° is much smaller than the wear of the rack when the contact angle between the rack and the support seat is less than 15°. Therefore, when the rack is driven by multiple steering angle actuators, selecting a contact angle of 15°-33° to support the rack can effectively reduce the wear by 65%.

[0025] One end of the rack 2 is provided with a connecting tooth A9, and one end of the rack 2 is provided with a connecting tooth B10. The connecting tooth A9 and the connecting tooth B10 are respectively connected to the gear shaft 7 at the ends of the housing 1; the phase angles of the connecting tooth A9 and the connecting tooth B10 are the same. Since the two ends of the rack are assisted by the motor respectively, and the phase angles of the connecting tooth A9 and the connecting tooth B10 are the same, the force at the two ends of the rack can be consistent, so that the circumferential force at the two ends of the rack can be completely offset, so that it is not easy to affect the movement of the rack.

[0026] Experimental verification: The experiment was conducted with the phase angles of the connecting teeth at both ends of the rack being 0° (same phase angle) and 5° (different phase angle) as variables, and the other conditions of the experiment were the same. The other conditions of the experiment were that the rotation speed of the gear shaft was 30-45rpm / min, the rack ends were unloaded, the rack stroke was 90% of the full stroke, and the lubrication method was grease coating. During the experiment, the force and force fluctuation of the rack were statistically analyzed.

[0027] When the phase angle of the connecting teeth at both ends of the rack is 0°, the forces on the rack are: left average moment: 1.264Nm; right average moment: 1.24Nm; left fluctuation: 0.3819Nm; right fluctuation: 0.3640Nm (see Fig.10 ).

[0028] When the phase angle of the connecting teeth at both ends of the rack is 5°, the forces on the rack are: left average moment: 1.475Nm; right average moment: 1.437Nm; left fluctuation: 0.5602Nm; right fluctuation: 0.5338Nm (see Fig.11 ).

[0029] From the above data comparison, it is not difficult to see that when the phase angle of the connecting teeth at both ends of the rack is 0°, the force on the rack is significantly better than when the phase angle of the connecting teeth at both ends of the rack is 5°, and the force and torque fluctuations of the rack are reduced. In the actual driving process of the vehicle, it is manifested as a smoother and faster rack movement and smoother steering.

[0030] When the steering actuator with enhanced steering speed turns the steering wheel to steer, the steering wheel control center transmits the steering signal to the main controller 5 at both ends of the housing 1 respectively. The main controller 5 controls the drive motor 6 to rotate, and the drive motor 6 drives the rack 2 to move through the worm gear and the gear shaft 7 in turn, and then the moving rack 5 pulls the wheel to deflect through the ball head tie rod 3 to steer. During the steering process, the rotation of the gear shaft 7 is detected by the single-axis angle signal sensor 8, and then the steering is detected. The single-axis angle signal sensor 8 transmits the detection signal to the main controller 5. After calculation, the main controller 5 controls the drive motor 6 again to form a closed-loop control until the gear shaft 7 rotates to the set angle, so that during the rotation of the gear shaft 7, the wheel is deflected to the set angle through the rack 2 and the ball head tie rod 3 in turn, thereby ensuring that the steering is completed.

[0031] The steering wheel of the steering actuator with enhanced steering speed is decoupled from the steering gear, which can achieve a flexible transmission ratio. The steering wheel angle can be fully rotated by 150°, so that the driver does not need to cross his hands when driving the vehicle to fully turn the direction, which is more convenient for parking and entering the garage, and the steering wheel turns more quickly; because the steering wheel rotation angle is reduced, and the drive motor can rotate faster without restriction, it can turn faster, and it only takes 1s to turn at full angle on the spot, so that it can quickly turn around on the spot; at the same time, the steering wheel is decoupled from the steering gear, and the steering gear can work without being restricted by the steering wheel rotation, and can turn faster, so as to meet the steering speed requirements of automatic driving or L3 or above assisted driving. In addition, steering and steering assistance are carried out through multiple steering actuators, and the torque can be evenly distributed through multiple steering actuators, which can effectively reduce the torque borne by a single steering actuator while ensuring the output of a large total torque, thereby effectively reducing the size of a single steering actuator; at the same time, the intermediate shaft, input shaft and torsion bar are eliminated, so that the steering gear is decoupled from the steering wheel, further reducing the space occupied in the cabin, and making the cabin and chassis layout more flexible. The problem that the existing steering gear has slow steering speed and is difficult to meet the requirements of automatic driving is solved.

Claims

1. A steering actuator for enhancing steering speed, comprising a housing (1), a rack (2), a ball tie rod (3) and a steering actuator, wherein the housing (1) is provided with a rack (2) via a support seat (4), and both ends of the rack (2) are provided with ball tie rods (3), characterized in that: Steering actuators are respectively arranged at the two end heads of the housing (1), and the steering actuators include a main controller (5) connected to a steering wheel control central line, a drive motor (6), a worm gear and a gear shaft (7), the drive motor (6) is electrically connected to the main controller (5), the output shaft of the drive motor (6) is connected to the gear shaft (7) via the worm gear, and the gear shaft (7) is meshed with the rack (2).

2. A steering actuator for enhancing steering speed according to claim 1, characterized in that: The gear shafts (7) are respectively provided with single-axis angle signal sensors (8) for detecting the rotation angle of the gear shafts (7), and the single-axis angle signal sensors (8) are electrically connected to the main controller (5).

3. A steering actuator for enhancing steering speed according to claim 1, characterized in that: The main controller (5) is connected to the steering wheel control center via a CAN bus.

4. A steering actuator for enhancing steering speed according to claim 1, characterized in that: The contact angle between the rack (2) and the support seat (4) is 15°-33°.

5. A steering actuator for enhancing steering speed according to claim 4, characterized in that: The contact angle between the rack (2) and the support seat (4) is 30°.

6. The steering actuator for enhancing steering speed according to claim 1, characterized in that: One end of the rack (2) is provided with a connecting tooth A (9), and one end of the rack (2) is provided with a connecting tooth B (10). The connecting tooth A (9) and the connecting tooth B (10) are respectively connected to the gear shaft (7) at the two ends of the housing (1); the phase angles of the connecting tooth A (9) and the connecting tooth B (10) are the same.

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