A new rear wheel steering device

Abstract

The utility model discloses a novel rear wheel steering device relates to automobile steering technical field, aims at solving the problem of relatively lower transmission efficiency, the structure of displacement sensor mechanism is complicated in prior art, adopts the technical scheme that the shell assembly has the screw rod inside, the planetary roller assembly is engaged outside the screw rod, the nut is engaged outside the planetary roller assembly, and the nut is fixed with the shell assembly through the bearing between, the other end of nut is fixed with worm wheel, and the screw rod has the pull rod on both sides, and there is the steering limit mechanism between pull rod and shell assembly, and the steering limit mechanism includes response module and sliding module, and sliding module is linked with pull rod, the utility model discloses the transmission structure of screw rod, planetary roller assembly and nut, make the rolling friction between roller, nut and screw rod, realize smaller wear, through the design of sliding module and response module, can guarantee the stability of response sheet in the moving process, and can limit the torsion of pull rod.

Description

Technical Field

[0001] This utility model relates to the field of automotive steering technology, specifically a novel rear-wheel steering device. Background Technology

[0002] With the rapid development of automotive intelligence and electrification technologies, modern vehicles place higher demands on handling performance and chassis integrated control. Rear wheel steering, as a key technology for improving vehicle agility and stability, is gradually being applied to mid-to-high-end passenger vehicles. This system independently controls the rear wheel steering angle, enabling the rear wheels to rotate in the opposite direction to the front wheels at low speeds to reduce the turning radius and improve parking and narrow-corner handling; at high speeds, the rear wheels rotate in the same direction as the front wheels to enhance vehicle stability and support high-speed lane changes and emergency obstacle avoidance. With the widespread adoption of advanced driver assistance systems (such as LKA, ACC, and APA), and the increasing demands on chassis precision and response speed for higher levels of autonomous driving (especially Level 3 and above), rear wheel steering is becoming a key component of intelligent chassis systems and is gaining widespread industry attention due to its ability to effectively improve trajectory tracking capabilities and anti-interference performance.

[0003] The current rear-wheel steering system mainly adopts a trapezoidal lead screw and belt pulley assembly structure, and the spindle limiting mechanism and displacement sensor are arranged separately. It has the following main problems: 1. The transmission efficiency of trapezoidal lead screws is relatively low, mainly due to the sliding friction between their thread surfaces, which leads to a higher demand for motor output torque and higher cost. 2. The spindle limit and displacement sensor mechanism has a complex structure and occupies a large space; 3. The spindle limiting mechanism and the displacement sensor sensing part are arranged separately. Its structure is complex and it is arranged in two positions, which puts high requirements on the parts and occupies a lot of space. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the existing defects and provide a new type of rear wheel steering device that can effectively solve the problems in the background art.

[0005] To achieve the above objectives, this utility model discloses a novel rear wheel steering device. The technical solution includes a housing assembly containing a lead screw, which meshes with a planetary roller assembly. The planetary roller assembly meshes with a nut, which is fixed to the housing assembly via a bearing. The other end of the nut is fixed to a worm gear. The housing assembly has a motor controller assembly, which includes a servo motor and a control module. A worm gear is connected to the output shaft of the servo motor and rotatably connects to the inside of the housing assembly, meshing with the worm gear. There are pull rods on both sides of the lead screw, and a steering limiting mechanism is located between the pull rods and the housing assembly. The steering limiting mechanism includes a sensing module and a sliding module. The sensing module is fixed to the housing assembly, and the sliding module is connected to the pull rods. The relative position of the sliding module is sensed by the sensing module to determine the position of the pull rods.

[0006] As a preferred technical solution of this utility model, the planetary roller assembly includes a cage and rollers. The cage and the lead screw are concentrically arranged and do not contact each other. Multiple rollers are arranged in a ring on the cage, and the rollers are rotatably connected to the cage. The rollers are engaged with the lead screw.

[0007] As a preferred technical solution of this utility model, the cage has end face bearings on both sides, the outer diameter of the end face bearings is matched with the inner diameter of the nut, and there is a fixed stop on the other side of the end face bearings, the fixed stop is interference-fitted with the inner diameter of the nut.

[0008] As a preferred technical solution of this utility model, the bearing and the nut are in transition fit. There is a locking nut on one side of the bearing, which is threaded to the outer diameter of the nut. There is a locking stud on the other side of the bearing, which is threaded to the inner diameter of the housing assembly, thereby achieving the fixation between the nut, the bearing and the housing assembly.

[0009] As a preferred technical solution of this utility model, the sensing module includes a sliding cavity, which is integrated with the housing assembly. A displacement sensor is located at the top of the sliding cavity, and the displacement sensor is electrically connected to the motor controller assembly.

[0010] As a preferred technical solution of this utility model, the sliding module includes a ball end screw, which is threadedly connected to the pull rod. The ball end screw has a limit block, which is a separate design and is fastened to the ball end screw. There is an O-ring between the ball end screw and the limit block, and a sensing plate is on the top of the limit block.

[0011] As a preferred technical solution of this utility model, the two sides of the lead screw are threadedly connected to the pull rod.

[0012] Compared with the prior art, the beneficial effects of this utility model are: the transmission structure of the lead screw, planetary roller assembly and nut enables rolling friction between the rollers, nut and lead screw, resulting in less wear, improved transmission efficiency and extended service life of core components. The design of sliding module and sensing module can ensure the stability of the sensing plate during movement and limit the torsion of the pull rod. The main components are compactly designed, which greatly saves installation space. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a partial cross-sectional view of the structure of this utility model; Figure 3 This is an enlarged view of section A of the structure of this utility model; Figure 4 This is an enlarged view of section B of the structure of this utility model; Figure 5 This is an exploded view of the planetary roller assembly of this utility model; Figure 6 This is an exploded view of the sliding module of this utility model.

[0014] In the diagram: 1. Housing assembly; 2. Lead screw; 3. Planetary roller assembly; 301. Cage; 302. Roller; 4. Nut; 5. Bearing; 6. Locking stud; 7. Locking nut; 8. Worm gear; 9. Motor controller assembly; 10. Tie rod; 11. Sliding cavity; 12. Displacement sensor; 13. Ball end screw; 15. Sensing plate; 16. Worm gear; 17. Fixing screw; 18. Limit block; 19. O-ring; 20. Fixing stop; 21. End face bearing. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example 1

[0016] like Figures 1 to 6As shown, this utility model discloses a novel rear wheel steering device. The technical solution includes a housing assembly 1, inside which is a lead screw 2. The lead screw 2 is externally engaged with a planetary roller assembly 3. The planetary roller assembly 3 includes a cage 301 and rollers 302. The cage 301 is concentrically arranged with the lead screw 2 but does not contact it. Multiple rollers 302 are arranged in a ring array on the cage 301, and the rollers 302 are rotatably connected to the cage 301. The rollers 302 mesh with the lead screw 2, thereby achieving small clearance, high rigidity, and improved efficiency. End face bearings 21 are located on both sides of the cage 301. The outer diameter of the end face bearings 21 matches the inner diameter of the nut 4. On the other side of 1, there is a fixed stop 20, which is interference-fitted with the inner diameter of the nut 4 to limit the movement of the planetary roller assembly 3. The roller 302 externally engages with the nut 4. The nut 4 is fixed to the housing assembly 1 by a bearing 5, which is an intermediate fit with the nut 4. On one side of the bearing 5, there is a locking nut 7, which is threaded to the outer diameter of the nut 4. On the other side of the bearing 5, there is a locking stud 6, which is threaded to the inner diameter of the housing assembly 1, thereby fixing the nut 4, the bearing 5, and the housing assembly 1. The other end of the nut 4 is fixed to the worm gear 8 by a fixing screw 17. The housing assembly 1 has a motor controller group 9. Group 9 includes a servo motor and a control module. The control module receives steering commands and controls the rotation of the servo motor. A worm gear 16 is connected to the output shaft of the servo motor. The worm gear 16 is rotatably connected to the inside of the housing assembly 1 and meshes with the worm wheel 8. The lead screw 2 is threadedly connected to the pull rod 10 on both sides. There is a steering limit mechanism between the pull rod 10 and the housing assembly 1. The steering limit mechanism includes a sensing module and a sliding module. The sensing module is fixed to the housing assembly 1 and includes a sliding cavity 11, which is integrated with the housing assembly 1. A displacement sensor 12 is located at the top of the sliding cavity 11. The displacement sensor 12 is an inductive non-contact displacement sensor. Electrically connected to the motor controller group 9, the sliding cavity 11 contains a sliding module, which is connected to the pull rod 10. The sliding module includes a ball head screw 13, which is threadedly connected to the pull rod 10. The ball head screw 13 has a limit block 18, which is made of plastic and has lubricating oil for lubrication. The limit block 18 is a separate design and is fastened to the ball head screw 13. There is an O-ring 19 between the ball head screw 13 and the limit block 18 for buffering, thereby limiting the circumferential movement of the pull rod 10 and preventing abnormal noise. The top of the limit block 18 has a sensor plate 15, which senses the relative position of the sliding module through the sensor module to determine the position of the pull rod 10.

[0017] The working principle of this utility model is as follows: After receiving the vehicle steering command, the motor controller group 9 controls the servo motor to rotate. The output shaft of the servo motor drives the worm gear 16 to rotate. The worm gear 16 meshes with the worm wheel 8 for transmission. The rotation of the worm wheel 8 drives the nut 4 to rotate inside the housing assembly 1. The nut 4 meshes with the lead screw 2 through the planetary roller assembly 3, converting the rotational motion into the axial linear motion of the lead screw 2, which in turn drives the tie rods 10 on both sides to move axially, thereby realizing the steering of the rear wheels. At the same time, the tie rod 10 drives the ball head screw 13 of the sliding module to move in the sliding cavity 11. The sensing plate 15 and the limit block 18 follow the movement of the ball head screw 13. The limit block 18 can limit the circumferential movement of the tie rod 10 to prevent abnormal noise. The displacement sensor 12 monitors the position signal of the sensing plate 15 in real time. The motor controller group 9 confirms the difference between the target displacement and the actual displacement based on the feedback signal, and then revises the control strategy in real time to realize closed-loop control.

[0018] The circuits and mechanical connections involved in this utility model are common practices used by those skilled in the art, and technical inspiration can be obtained through a limited number of experiments. They are common knowledge.

[0019] Components not described in detail in this article are existing technologies.

[0020] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A novel rear-wheel steering device, comprising a housing assembly (1), characterized in that: Inside the housing assembly (1) is a lead screw (2), which meshes with a planetary roller assembly (3) on the outside. The planetary roller assembly (3) meshes with a nut (4) on the outside. The nut (4) is fixed to the housing assembly (1) by a bearing (5). The other end of the nut (4) is fixed to a worm wheel (8). The housing assembly (1) has a motor controller group (9), which includes a servo motor and a control module. The output shaft of the servo motor is connected to a worm (16). The worm (16) is rotatably connected to the inside of the housing assembly (1) and meshes with the worm wheel (8). There are pull rods (10) on both sides of the lead screw (2). There is a steering limit mechanism between the pull rod (10) and the housing assembly (1). The steering limit mechanism includes a sensing module and a sliding module. The sensing module is fixed to the housing assembly (1), and the sliding module is connected to the pull rod (10). The relative position of the sliding module is sensed by the sensing module to realize the judgment of the position of the pull rod (10).

2. A novel rear-wheel steering device according to claim 1, characterized in that: The planetary roller assembly (3) includes a cage (301) and rollers (302). The cage (301) is concentrically arranged with the lead screw (2) and does not contact it. Multiple rollers (302) are arranged in a ring on the cage (301) and are rotatably connected to the cage (301). The rollers (302) mesh with the lead screw (2).

3. A novel rear-wheel steering device according to claim 2, characterized in that: The cage (301) has end face bearings (21) on both sides. The outer diameter of the end face bearings (21) matches the inner diameter of the nut (4). The other side of the end face bearings (21) has a fixed stop (20). The fixed stop (20) is interference-fitted with the inner diameter of the nut (4).

4. A novel rear-wheel steering device according to claim 1, characterized in that: The bearing (5) and the nut (4) are in transition fit. There is a locking nut (7) on one side of the bearing (5), which is threaded to the outer diameter of the nut (4). There is a locking stud (6) on the other side of the bearing (5), which is threaded to the inner diameter of the housing assembly (1), thereby achieving the fixation between the nut (4), the bearing (5) and the housing assembly (1).

5. A novel rear-wheel steering device according to claim 1, characterized in that: The sensing module includes a sliding cavity (11), which is integrated with the housing assembly (1). A displacement sensor (12) is located on the top of the sliding cavity (11), and the displacement sensor (12) is electrically connected to the motor controller assembly (9).

6. A novel rear-wheel steering device according to claim 1, characterized in that: The sliding module includes a ball head screw (13), which is threadedly connected to the pull rod (10). The ball head screw (13) has a limit block (18), which is a separate design and is fastened to the ball head screw (13). There is an O-ring (19) between the ball head screw (13) and the limit block (18). There is a sensor plate (15) on the top of the limit block (18).

7. A novel rear-wheel steering device according to claim 1, characterized in that: The lead screw (2) is threaded to the pull rod (10) on both sides.

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