A roller screw transmission pair structure and a pure electric steering gear having the same

Abstract

The utility model relates to the field of steering gears, specifically a roller screw transmission pair structure and a pure electric steering gear having the same. It includes a hole elastic ring, a planet carrier, an inner gear ring, a steering nut, a roller and a steering screw; the steering nut has an internal thread, and both ends of the axial direction have coaxially distributed circular stepped holes a; the inner gear ring is installed at each of the two stepped holes a, and its outer end has a circular stepped hole b; the hole elastic ring is arranged on the steering nut and pressed against the outer side of the inner gear ring; the planet carrier is coaxially installed at the stepped hole b; a plurality of rollers are evenly distributed around the planet carrier, and it has an external thread a meshing with the internal thread of the steering nut, and both ends of the rollers have an external gear part and an optical axis part, the optical axis part is rotatably arranged on the planet carrier, and the external gear part meshes with the inner gear ring. The utility model is suitable for high-speed, high-precision and high-load use conditions, the transmission pair has high transmission efficiency, can withstand high loads and high impacts, and has a long service life.

Description

Technical Field

[0001] The utility model relates to the field of steering gears, in particular to a roller screw transmission pair structure and a pure electric steering gear having the same. Background Art

[0002] With the rapid development of the automotive industry, the performance and efficiency of steering gears are crucial to the maneuverability, safety and comfort of vehicles. Traditional steering gear designs are often limited by the performance of their transmission systems and are difficult to meet the growing performance requirements of automobiles.

[0003] Traditional steering gear transmission pairs are mostly ball screw transmission pairs, which cannot meet the requirements of high speed, high precision and high load. In addition, the steering assistance mode of commercial vehicles is generally hydraulic, and some light trucks use electric recirculating ball steering assistance. However, due to structural limitations, recirculating ball steering cannot withstand high loads and high impacts, and the steel balls and raceways are prone to wear, so the service life is short. Utility Model Content

[0004] The purpose of the utility model is to address the problems existing in the background technology and to propose a roller screw transmission pair structure and a pure electric steering gear having the same, which is suitable for high-speed, high-precision and high-load use conditions. The transmission pair has high transmission efficiency, can withstand high loads and high impacts, and has a long service life.

[0005] On the one hand, the utility model proposes a roller screw transmission pair structure, including a hole elastic retaining ring, a planetary carrier, an inner gear ring, a steering nut, a roller and a steering screw; the steering nut has an internal thread, and both axial ends have coaxially distributed circular stepped holes a; one inner gear ring is installed at each of the two stepped holes a, and its outer end has a circular stepped hole b; the hole elastic retaining ring is arranged on the steering nut and pressed against the outer side of the inner gear ring; the planetary carrier is coaxially installed at the stepped hole b; a plurality of rollers are evenly distributed around the planetary carrier, and have an external thread a meshing with the internal thread of the steering nut, and both ends of the rollers have an external gear part and an optical axis part, the optical axis part is rotatably arranged on the planetary carrier, and the external gear part meshes with the inner gear ring; the steering screw is coaxially distributed with the steering nut, and has an external thread b meshing with the roller external thread a, and has an axially distributed rack part on the outer peripheral surface.

[0006] On the other hand, the utility model proposes a pure electric steering gear, including the above-mentioned roller screw transmission pair structure, and also includes a mounting assembly, an input assembly, a housing, a rocker shaft and a drive assembly; the input assembly is arranged on the mounting assembly and is connected to the steering screw to detect the input torque signal; a bearing is arranged between the housing and the steering screw; the rocker shaft is rotatably arranged on the housing and has an incomplete gear portion meshing with the rack portion; the drive assembly is arranged on the mounting assembly and is transmission-connected to the steering screw.

[0007] Preferably, the mounting assembly includes a box body connected to the shell and an upper cover connected to the box body through a first bolt.

[0008] Preferably, the input assembly includes a torsion bar having one end connected to one end of a steering screw, an input shaft sleeved on the torsion bar and rotatably arranged on the upper cover, a cylindrical pin connecting the torsion bar and the input shaft, a torque angle sensor arranged on the steering screw, and a magnetic ring arranged on the input shaft and facing the torque angle sensor.

[0009] Preferably, the drive assembly includes a motor mounted on the housing via a second bolt, a coupling connected to the output end of the motor, a worm connected to the coupling and rotatably disposed on the housing, and a worm wheel mounted on the steering screw and meshingly connected to the worm.

[0010] Preferably, a controller is provided on the motor, and a wiring harness is connected between the controller and the torque angle sensor.

[0011] Preferably, the housing is connected with an adjusting screw plug for axially locking the steering screw, and a locking nut is sleeved on the outer circumference of the adjusting screw plug.

[0012] Compared with the prior art, the utility model has the following beneficial technical effects:

[0013] The utility model is suitable for use under high-speed, high-precision and high-load conditions. The transmission pair has high transmission efficiency, can withstand high loads and high impacts, and has a long service life. When in use, the steering screw is driven to rotate, and the steering screw drives the multiple meshing rollers to rotate, and the rollers drive the steering nut to move in a straight line. Multiple rollers participate in the movement at the same time, with many contact points and less wear. It can withstand larger loads and stresses, and thus can greatly improve the service life. The requirements for the use environment are low, and good performance can still be guaranteed in poor environments. The pure electric steering gear can achieve two deceleration and torque increase. By changing the transmission mode of the transmission pair, the load-bearing capacity, transmission efficiency and service life of the pure electric steering gear are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view of the roller screw transmission pair structure of the embodiment of the utility model;

[0015] Figure 2 This is a partial structural cross-sectional view of a pure electric steering gear according to an embodiment of the utility model;

[0016] Figure 3 It is a side view of the pure electric steering gear according to an embodiment of the utility model.

[0017] Figure numerals: 1. cylindrical pin; 2. torsion bar; 3. input shaft; 4. first bolt; 5. upper cover; 6. housing; 7. magnetic ring; 8. torque angle sensor; 9. worm gear; 10. anti-loosening nut; 11. adjusting plug; 12. elastic retaining ring for hole; 13. planetary carrier; 14. inner ring gear; 15. steering nut; 16. roller; 17. thrust angular contact ball bearing; 18. steering screw; 19. housing; 20. rocker shaft; 21. second bolt; 22. wiring harness; 23. deep groove ball bearing; 24. worm; 25. shock absorber pad; 26. coupling; 27. motor; 28. controller. DETAILED DESCRIPTION

[0018] Embodiment 1

[0019] like Figure 1 As shown, a roller screw transmission pair structure proposed in this embodiment includes a hole elastic ring 12, a planet carrier 13, an inner gear ring 14, a steering nut 15, a roller 16 and a steering screw 18.

[0020] The steering nut 15 has an internal thread and has coaxially distributed circular stepped holes a at both ends of the axial direction. An inner gear ring 14 is installed at each of the two stepped holes a. The inner gear ring 14 is pressed into the inner side of the steering nut 15 with interference fit, and its outer end has a circular stepped hole b. The hole elastic circlip 12 is set on the steering nut 15 and pressed against the outer side of the inner gear ring 14. The two hole elastic circlips 12 fix the two inner gear rings 14 respectively to ensure that the roller 16 is fully supported and has no axial movement. The planet carrier 13 is coaxially installed at the stepped hole b of the inner gear ring 14.

[0021] There are multiple rollers 16 evenly distributed around the planetary carrier 13. They have external threads a that mesh with the internal threads of the steering nut 15. Both ends of the rollers have external gear parts and optical axis parts. The optical axis part is rotatably set on the planetary carrier 13, and the external gear part meshes with the internal gear ring 14. The external gear part and the internal gear ring 14 have the same module but different numbers of teeth, ensuring that the rollers 16 are axially parallel to the steering screw 18 and the steering nut 15.

[0022] The steering screw 18 is coaxially arranged with the steering nut 15 , has an external thread b meshing with the external thread a of the roller 16 , and has a rack portion arranged in the axial direction on the outer peripheral surface.

[0023] This embodiment is suitable for high-speed, high-precision and high-load conditions. The transmission pair has high transmission efficiency, can withstand high loads and high impacts, and has a long service life. When in use, the steering screw 18 is driven to rotate, and the steering screw 18 drives the meshing multiple rollers 16 to rotate, and the rollers 16 drive the steering nut 15 to move in a straight line. Multiple rollers 16 participate in the movement at the same time, with many contact points, small wear, and can withstand large loads and stresses, so the service life can be greatly improved. The requirements for the use environment are low, and good performance can still be guaranteed in poor (dirty or poorly lubricated) environments. Compared with the traditional ball screw transmission pair, this transmission pair cancels the outer circulation parts such as the steel ball conduit and the conduit clamp, so it has high transmission speed and acceleration, and fewer parts are easy to disassemble and process, and can reduce noise.

[0024] Embodiment 2

[0025] like Figure 1-Figure 3 As shown, a pure electric steering gear proposed in this embodiment includes the roller screw transmission pair structure in the first embodiment, and also includes a mounting assembly, an input assembly, a housing 19, a rocker shaft 20 and a drive assembly.

[0026] The mounting assembly includes a box body 6 connected to the housing 19 and an upper cover 5 connected to the box body 6 via a first bolt 4 .

[0027] The input assembly is arranged on the mounting assembly and connected to the steering screw 18 to detect the input torque signal. The input assembly includes a torsion bar 2 connected to one end of the steering screw 18, an input shaft 3 sleeved on the torsion bar 2 and rotatably arranged on the upper cover 5, a cylindrical pin 1 connecting the torsion bar 2 and the input shaft 3, a torque angle sensor 8 arranged on the steering screw 18, and a magnetic ring 7 arranged on the input shaft 3 and facing the torque angle sensor 8. The magnetic ring 7 is used in conjunction with the torque angle sensor 8, and the torque angle sensor 8 adopts a non-contact sensor. When the driver turns the steering wheel, the torsion bar 2 is twisted and deformed, and the torque angle sensor 8 detects the torque signal and converts it into an electrical signal, and sends the signal to the controller 28 at the same time.

[0028] A bearing is provided between the housing 19 and the steering screw 18 , and the bearing is a thrust angular contact ball bearing 17 .

[0029] The rocker arm shaft 20 is rotatably arranged on the housing 19 and has an incomplete gear portion meshing with the rack portion. When the steering nut 15 moves in a straight line, the rocker arm shaft 20 with the incomplete gear portion can be driven to rotate through the rack portion, thereby achieving steering assistance.

[0030] The driving assembly is arranged on the mounting assembly and is connected to the steering screw 18 in a transmission manner. The driving assembly includes a motor 27 installed on the housing 6 through a second bolt 21, a coupling 26 connected to the output end of the motor 27, a worm 24 connected to the coupling 26 and rotatably arranged on the housing 6, and a worm wheel 9 sleeved on the steering screw 18 and meshingly connected with the worm 24. The motor 27 drives the worm 24 to rotate through the coupling 26, the worm 24 drives the worm wheel 9 to rotate, and the worm wheel 9 drives the steering screw 18 to rotate to provide assistance. A shock-absorbing pad 25 is arranged at the coupling 26 to reduce noise. The worm 24 is rotatably mounted on the housing 6 through a deep groove ball bearing 23. A controller 28 is provided on the motor 27. A wiring harness 22 is connected between the controller 28 and the torque angle sensor 8. The torque angle sensor 8 transmits the detected torque signal to the controller 28 through the wiring harness 22. After the controller 28 makes judgments and processes the torque signal, vehicle speed signal, etc., it gives the assist direction and assist current of the motor according to a predetermined assist characteristic curve, controls the motor to output the assist torque, and completes the steering assist control.

[0031] The housing 19 is connected with an adjusting screw plug 11 for axially locking the steering screw 18 , and a locking nut 10 is sleeved on the outer circumference of the adjusting screw plug 11 .

[0032] In this embodiment, the worm 24 drives the worm wheel 9 to rotate, achieving deceleration and torque increase, and the steering screw 18 converts the rotational motion into the linear motion of the steering nut 15 through the roller screw transmission pair structure. The steering nut 15 then drives the rocker shaft 20 to rotate, converting the linear motion of the steering nut 15 into the rotational motion of the rocker shaft 20, and achieving deceleration and torque increase again. The pure electric steering gear improves the load capacity, transmission efficiency and service life of the pure electric steering gear by changing the transmission mode of the transmission pair.

[0033] The implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto, and various changes can be made within the knowledge scope of technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A roller screw transmission pair structure, characterized in that: include: A steering nut (15) having an internal thread and coaxially distributed circular stepped holes a at both axial ends; An inner gear ring (14), one of which is installed at each of the two stepped holes a, and has a circular stepped hole b at its outer end; A hole elastic retaining ring (12) is arranged on the steering nut (15) and pressed against the outside of the inner gear ring (14); A planet carrier (13) coaxially mounted at the stepped hole b; A plurality of rollers (16) are evenly distributed around the planet carrier (13), each having an external thread a meshing with the internal thread of the steering nut (15), and both ends of the rollers have an external gear portion and an optical axis portion, the optical axis portion is rotatably arranged on the planet carrier (13), and the external gear portion meshes with the internal gear ring (14); The steering screw (18) is coaxially distributed with the steering nut (15), has an external thread b meshing with the external thread a of the roller (16), and has a rack portion distributed along the axial direction on the outer peripheral surface.

2. A pure electric steering gear, characterized in that: The roller screw transmission pair structure according to claim 1 further comprises: Install components; An input assembly, which is disposed on the mounting assembly and connected to the steering screw (18) to detect an input torque signal; A housing (19) having a bearing disposed between it and the steering screw (18); A rocker arm shaft (20) is rotatably mounted on the housing (19) and has an incomplete gear portion meshingly connected with the rack portion; A driving assembly is arranged on the mounting assembly and is drivingly connected to the steering screw rod (18).

3. The pure electric steering gear according to claim 2, characterized in that: The mounting assembly comprises a box body (6) connected to a housing (19) and an upper cover (5) connected to the box body (6) via a first bolt (4).

4. The pure electric steering gear according to claim 3, characterized in that: The input assembly comprises a torsion bar (2) having one end connected to one end of a steering screw (18), an input shaft (3) sleeved on the torsion bar (2) and rotatably arranged on an upper cover (5), a cylindrical pin (1) connecting the torsion bar (2) and the input shaft (3), a torque angle sensor (8) arranged on the steering screw (18), and a magnetic ring (7) arranged on the input shaft (3) and facing the torque angle sensor (8).

5. The pure electric steering gear according to claim 4, characterized in that: The driving assembly comprises a motor (27) mounted on a housing (6) via a second bolt (21), a coupling (26) connected to an output end of the motor (27), a worm (24) connected to the coupling (26) and rotatably arranged on the housing (6), and a worm wheel (9) sleeved on a steering screw (18) and meshingly connected to the worm (24).

6. The pure electric steering gear according to claim 5, characterized in that: A controller (28) is provided on the motor (27), and a wiring harness (22) is connected between the controller (28) and the torque angle sensor (8).

7. The pure electric steering gear according to claim 2, characterized in that: The housing (19) is connected with an adjusting screw plug (11) for axially locking the steering screw rod (18), and a locking nut (10) is sleeved on the outer periphery of the adjusting screw plug (11).

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