Integrated reducing mechanism power assembly of electric steering column

Abstract

The invention relates to an integrated reducing mechanism power assembly of an electric steering column, which comprises an external reducing mechanism shell, and a worm wheel shaft assembly is mounted on the right side in the reducing mechanism power assembly and is meshed with a worm shaft assembly on the left side; an upper bearing, a middle bearing and a lower bearing are fixed to the upper portion, the middle portion and the lower portion of the worm shaft assembly respectively, the lower half portion of the worm shaft is meshed with the worm gear to input torque, the upper half portion of the worm shaft is provided with a motor rotor assembly, and the motor rotor assembly and a stator assembly fixed to the inner wall of the speed reduction mechanism shell form a motor assembly to provide assistance. And a base is assembled at the tail part of the motor at the upper end, a PCBA for controlling the operation of the motor is assembled on the base, and the outside is sealed by an end cover to form an integrated speed reducing mechanism power assembly. The power-assisted motor and the speed reducing mechanism of the electric steering column are highly integrated, so that the number of parts is effectively reduced, and the cost is reduced; and the axial length of the motor is obviously shortened, so that the arrangement and the light weight of the whole vehicle are facilitated, and the positive significance is realized on the interior design and the endurance mileage improvement in the automobile industry.

Description

Technical Field

[0001] The invention relates to a highly integrated electric steering column, in particular to an electric steering column integrated speed reducing mechanism power assembly, belonging to the technical field of automobile electric steering systems. Background Art

[0002] With the development of the automobile industry, electric power steering systems (EPS) have been widely used in various types of vehicles. EPS uses motors to provide auxiliary torque to the steering system, reducing the manual input to the steering wheel. Compared with traditional hydraulic steering systems, EPS not only has high steering efficiency, good steering feel, and less structural space, but is also easy to control automatically, which is more conducive to the realization of future autonomous driving technology.

[0003] The reduction mechanism powertrain is a key component in EPS and plays the role of assisting torque amplification output. The traditional EPS reduction mechanism powertrain consists of two parts: the power-assisted motor and the reduction mechanism. The motor is fixed to the reduction mechanism by bolts, and the motor torque output end is connected to the worm in the reduction mechanism through a coupling and a buffer pad to transmit the motor power. The motor provides power, and the reduction mechanism amplifies the power to achieve EPS power steering. This structural principle is simple, and the modules are distributed and assembled, which is more convenient for production line production.

[0004] However, with the development of new energy vehicles in the existing technology, the shortcomings of this structure, such as low integration, large axial volume of the motor, large number of parts, large assembly mass and high cost, are becoming increasingly prominent, which is not conducive to the overall vehicle layout and the endurance of new energy vehicles. In view of the low integration, large volume and high cost of the current traditional EPS, we propose an integrated reduction mechanism powertrain to effectively solve the above problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an integrated speed reduction mechanism power assembly with reasonable structure and convenient assembly.

[0006] In order to achieve the above purpose, the specific technical scheme of the present invention is as follows: an integrated speed reduction mechanism power assembly, including a speed reduction mechanism housing, the interior of the speed reduction mechanism housing is rotatably connected with a worm shaft and a worm wheel shaft assembly, the worm shaft and the worm wheel shaft assembly are meshed, and a lower bearing is sleeved and pressed between the lower part of the worm shaft and the speed reduction mechanism housing; the outer ring of the lower end bearing is interference fit with the speed reduction mechanism housing and clearance fit with the worm shaft; A motor stator assembly is fixedly installed in the motor cavity on the left side of the reduction mechanism housing, a motor rotor assembly is fixedly installed on the top of the worm shaft, an upper cover is fixedly connected to the top of the reduction mechanism housing, and an upper bearing is sleeved and pressed between the upper part of the worm shaft and the upper cover; A shaft retaining ring and a middle bearing are fixedly connected to the middle of the outer surface of the worm shaft, the inner ring of the middle bearing has an interference fit with the worm bearing, and the outer ring has a clearance fit with the reduction mechanism housing; the outer surface of the shaft retaining ring abuts against the inner side wall of the reduction mechanism housing.

[0007] Furthermore, a flat square is fixedly connected to the upper end of the worm shaft. During assembly, the flat square can be used to clamp the worm shaft to prevent the worm shaft from rotating when tightening the locking nut. It can also be used as a torque output interface for motor assembly performance testing.

[0008] A retaining ring groove matching the shaft retaining ring is provided in the middle of the outer surface of the worm shaft. When the bearing is pressed, the retaining ring is installed to prevent the middle bearing from axial displacement and fixation failure. A retaining shoulder is fixedly connected to the middle of the outer surface of the worm shaft and corresponding to the position below the middle bearing. It can be used for bearing press-fitting limit and motor rotor assembly press-fitting limit to prevent the worm tooth shape from being deformed by force during press-fitting, which affects the meshing effect.

[0009] The bottom of the worm shaft is fixedly connected with a lower bearing limiting step, and the lower surface of the lower bearing limiting step is in close contact with the upper surface of the lower bearing. The locking nut cooperates with the lower end bearing to jointly restrict the axial movement of the worm rotor assembly. The end of the lower end bearing is compressed by the tail cover nut to prevent the risk of the bearing loosening and also to seal the mechanism.

[0010] Furthermore, the outer surface of the middle bearing is symmetrically and evenly spaced with O-ring grooves, and O-rings are placed on the inner walls of the O-ring grooves. There are two O-ring grooves, which are evenly spaced and distributed on the outer ring of the middle bearing. Since the inner ring of the middle bearing and the worm bearing have an interference fit, and the outer ring and the speed reduction mechanism housing have a clearance fit, when the worm shaft and the worm wheel are meshed and run at high speed, the middle bearing will produce a deflection. The double O-rings can effectively suppress the impact sound of the bearing deflection on the speed reduction mechanism housing, thereby improving the quietness of the system.

[0011] Furthermore, a corrugated gasket for eliminating axial clearance is provided between the end face of the upper bearing and the end cover. The corrugated gasket can effectively suppress the axial clearance movement of the worm shaft, and at the same time produce a pre-tightening effect on the worm shaft, eliminate the clearance caused by the durable wear of the worm gear, and reduce the durable abnormal noise.

[0012] Furthermore, a thread is provided at the bottom of the worm shaft, a locking nut is threadedly sleeved on the outer surface of the thread, and the upper surface of the locking nut is in contact with the lower surface of the lower bearing.

[0013] Furthermore, a tail cover nut is threadedly connected through the bottom of the side wall of the reduction mechanism housing, and the tail cover nut is sleeved on the outside of the locking nut.

[0014] Furthermore, a PCBA board is fixedly mounted on the upper surface of the upper cover, a magnetic ring is abutted between the PCBA board and the upper cover, and the magnetic ring is sleeved on the top of the outer surface of the worm shaft, and the rotation of the motor is controlled by the magnetic ring and the PCBA board.

[0015] Furthermore, the upper surface of the upper cover is riveted and fixedly connected with a top cover made of steel material, and the top cover is sleeved on the outside of the PCBA board. The steel top cover can effectively prevent dust and foreign matter from damaging the PCBA and the motor, and can also isolate the influence of the external magnetic field on the controller. The riveted fixing structure is more convenient for rapid assembly.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The integration of the EPS reduction mechanism powertrain has been improved, and parts such as the motor housing, the motor and worm connection structure, and the worm locking structure have been eliminated, significantly reducing the cost of parts; 2. Through the combination design of subsystem parts, the product volume of EPS is reduced, the layout difficulty of the vehicle manufacturer is reduced, and the constraints on the vehicle interior design are also reduced, which is beneficial to the styling development of the vehicle manufacturer; 3. EPS reduces the number of parts, reduces the weight of the steering system, and reduces the load on the vehicle, which has a significant positive effect on improving the vehicle's endurance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] Figure 2 It is a schematic diagram of the structure of the housing stator assembly of the present invention.

[0019] Figure 3 It is a schematic diagram of the structure of the worm rotor assembly of the present invention.

[0020] Figure 4 It is a schematic diagram of the middle bearing structure of the present invention.

[0021] Figure 5 It is a schematic diagram of the worm shaft structure of the present invention.

[0022] Description of the drawings: 1. Top cover; 2. PCBA board; 3. Magnetic ring; 4. Upper cover; 5. Corrugated gasket; 6. Upper bearing; 7. Motor stator assembly; 8. Motor rotor assembly; 9. Shaft retaining ring; 10. Middle bearing; 10-1. O-ring groove; 10-2. O-ring; 11. Worm shaft; 11-1. Flat square; 11-2. Retaining ring groove; 11-3. Shoulder; 11-4. Lower bearing limit step; 11-5. Thread; 12. Worm shaft assembly; 13. Speed ​​reduction mechanism housing; 14. Lower bearing; 15. Locking nut; 16. Tail cover nut. DETAILED DESCRIPTION Example

[0023] The embodiment provides an electric steering column integrated speed reduction mechanism power assembly, the structure of which is as follows: Figure 1 As shown, it includes a reduction mechanism housing 13, the interior of which is rotatably connected with a worm shaft 11 and a worm wheel shaft assembly 12 (the right side of the reduction mechanism housing 13 is a worm wheel assembly groove), the worm shaft 11 is lengthened by 60 mm so that it is combined with the motor shaft, and the worm shaft 11 and the worm wheel shaft assembly 12 are meshed, and a lower bearing 14 is sleeved and pressed between the lower part of the worm shaft 11 and the reduction mechanism housing 13; A motor stator assembly 7 is fixedly installed in the motor cavity on the left side of the reduction mechanism housing 13, and a motor rotor assembly 8 is fixedly installed on the top of the worm shaft 11, wherein the motor rotor assembly 8 on the worm shaft 11 and the motor stator assembly 7 assembled in the extended inner cavity of the reduction mechanism housing 13 together form a booster motor; The top of the reduction mechanism housing 13 is fixedly connected with an upper cover 4, and an upper bearing 6 is pressed and mounted between the upper part of the worm shaft 11 and the upper cover 4. A shaft retaining ring 9 and a middle bearing 10 are fixedly connected to the middle of the outer surface of the worm shaft 11, and the outer surface of the shaft retaining ring 9 abuts against the inner side wall of the reduction mechanism housing 13.

[0024] In the present application, a motor stator, rotor, and PCBA assembly structure are developed and installed on the steering column reduction mechanism housing 13, and the reduction mechanism worm shaft is lengthened and combined with the motor shaft to integrate the steering column power-assist motor and the reduction mechanism into one, thereby realizing an integrated design structure integrating the power-assist motor and the reduction mechanism.

[0025] Specifically, a flat square 11-1 is fixedly connected to the upper end of the worm shaft 11, which can be used to fix the locking nut 15 when it is tightened, and can also be used as a torque output interface during assembly performance testing; a retaining ring groove 11-2 matching the shaft retaining ring 9 is opened in the middle of the outer surface of the worm shaft 11, and a retaining shoulder 11-3 is fixedly connected to the middle of the outer surface of the worm shaft 11 and corresponds to the position below the middle bearing 10, so that the lower end of the middle bearing 10 is limited by the retaining shoulder 11-3 and the upper end is limited by the shaft retaining ring 9 to prevent the middle bearing 10 from moving upward or downward and coming out, and can also be used for support during press-fitting of the motor stator assembly 8 to prevent the toothed part of the worm shaft 11 from being deformed due to the press-fitting pressure; The bottom of the worm shaft 11 is fixedly connected with a lower bearing limiting step 11-4, and the lower surface of the lower bearing limiting step 11-4 is in close contact with the upper surface of the lower bearing 14. Correspondingly, a thread 11-5 is provided at the bottom of the worm shaft 11, and the outer surface of the thread 11-5 is threadedly sleeved with a locking nut 15, and the upper surface of the locking nut 15 is in contact with the lower surface of the lower bearing 14, wherein the lower end surface of the worm shaft 11 is locked with the thread 11-5 at the lower part of the worm shaft 11 by the locking nut 15, thereby fixing the worm shaft 11, and the locking nut 15 and the lower bearing 14 are jointly constrained to prevent the axial movement of the worm shaft 11.

[0026] A tail cover nut 16 is threadedly connected to the bottom of the side wall of the reduction mechanism housing 13, and the tail cover nut 16 is sleeved on the outside of the locking nut 15 to tighten the outer ring of the lower bearing 14 to prevent the risk of the lower bearing 14 loosening and also to seal the mechanism.

[0027] The outer surface of the middle bearing 10 is symmetrically and evenly spaced with O-ring grooves 10-1, and the inner wall of the O-ring groove 10-1 is placed with an O-ring 10-2. Since the inner ring of the middle bearing 10 has an interference fit with the worm shaft 11, and the outer ring has a clearance fit with the reduction mechanism housing 13, when the worm shaft 11 and the worm wheel shaft assembly 12 are engaged and running at high speed, the double O-rings 10-2 can effectively suppress the impact of the outer ring of the bearing on the reduction mechanism housing 13, thereby reducing the generation of abnormal noise.

[0028] The upper surface of the upper cover 4 is fixedly mounted with a PCBA board 2, a magnetic ring 3 is abutted between the PCBA board 2 and the upper cover 4, and the magnetic ring 3 is sleeved on the top of the outer surface of the worm shaft 11, wherein the upper surface of the upper cover 4 is fixedly connected with a top cover 1, and the top cover 1 is sleeved on the outside of the PCBA board 2, so as to realize the independent sealing of the entire speed reduction mechanism housing 13 and the outside, which can effectively prevent dust and foreign matter from damaging the PCBA board 2 and the motor, and can also isolate the influence of the external magnetic field on the controller; The PCBA board 2 can control the rotation of the motor (servo motor of the reducer assembly) according to the signal. The motor assists the rotation of the worm shaft assembly 12 through the tooth meshing of the worm shaft 11, amplifies the output power of the motor and transmits it, realizing the EPS integrated reduction mechanism power steering.

[0029] When using the integrated speed reduction mechanism power assembly, first install the motor stator assembly 7 and the lower bearing 14 into the left cavity of the speed reduction mechanism housing 13 to form a housing stator assembly, then install the middle bearing 10 into the middle of the worm shaft 11, and then install the shaft retaining ring 9 into the retaining ring groove 11-2 in the middle of the worm shaft 11, and then install the motor stator assembly 7 into the upper part of the worm shaft 11, and fix the upper bearing 6 on the top to form a worm rotor assembly; Install the worm rotor assembly into the housing stator assembly, lock the lower end of the worm shaft 11 with the locking nut 15 and the thread 11-5 to fix the worm shaft 11, screw the tail cover nut 16 into the thread below the reduction mechanism housing 13, and press the outer ring of the lower bearing 14; assemble the rear cover 4 into the stopper above the assembly and fix it with bolts, press the magnetic ring 3 into the upper end of the worm shaft 11, and then fix the PCBA 2 on the upper cover 4 with bolts, and seal the outermost assembly with the upper cover 1 and fix it with rivets; install the worm wheel shaft assembly into the right groove of the reduction mechanism housing 13, and the worm wheel meshes with the lower teeth of the worm shaft 11, so as to realize the assembly of the entire reduction mechanism power assembly; To sum up, in this application, the reduction mechanism housing, worm shaft and worm gear shaft assembly are provided to improve the integration of the EPS reduction mechanism powertrain, eliminate parts such as the motor housing, the motor and worm connection structure, and the worm locking structure, and significantly reduce the parts cost. By reducing the number of parts through EPS, the weight of the steering system is reduced, and the load on the car is reduced, which has a significant positive effect on improving the car's endurance. In addition, through the combination design of subsystem parts, the product volume of EPS is reduced, the layout difficulty of the vehicle manufacturer is reduced, and the constraints on the car's interior design can be reduced, which is beneficial to the styling development of the vehicle manufacturer. In addition, the axial length of the motor is significantly shortened, which is more conducive to the layout and lightweight of the vehicle, and has positive significance for the interior design and mileage improvement of the automotive industry.

[0030] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. An electric steering column integrated speed reduction mechanism power assembly, comprising a speed reduction mechanism housing (13), characterized in that: The interior of the reduction mechanism housing (13) is rotatably connected to a worm shaft (11) and a worm wheel shaft assembly (12); the worm shaft (11) is lengthened and integrated with the motor shaft, and the worm shaft (11) and the worm wheel shaft assembly (12) are meshed with each other; a lower bearing (14) is sleeved and press-fitted between the lower portion of the worm shaft (11) and the reduction mechanism housing (13); the outer ring of the lower bearing is interference-fitted with the reduction mechanism housing and clearance-fitted with the worm shaft; A motor stator assembly (7) is fixedly mounted in the motor cavity on the left side of the speed reduction mechanism housing (13); a motor rotor assembly (8) is fixedly mounted on the top of the worm shaft (11); an upper cover (4) is fixedly connected to the top of the speed reduction mechanism housing (13); and an upper bearing (6) is sleeved and press-fitted between the upper part of the worm shaft (11) and the upper cover (4); A shaft retaining ring (9) and a middle bearing (10) are fixedly connected to the middle of the outer surface of the worm shaft (11); the inner ring of the middle bearing is interference-fitted with the worm shaft, and the outer ring is clearance-fitted with the reduction mechanism housing; the outer surface of the shaft retaining ring (9) is in contact with the inside of the side wall of the reduction mechanism housing (13).

2. The electric steering column integrated speed reduction mechanism power assembly according to claim 1, characterized in that: The upper end of the worm shaft (11) is fixedly connected to a flat square (11-1); a retaining ring groove (11-2) matching the shaft retaining ring (9) is provided in the middle of the outer surface of the worm shaft (11); a retaining shoulder (11-3) is fixedly connected to the middle of the outer surface of the worm shaft (11) and corresponds to a position below the middle bearing (10); the bottom of the worm shaft (11) is fixedly connected to a lower bearing limiting step (11-4), and the lower surface of the lower bearing limiting step (11-4) is in close contact with the upper surface of the lower bearing (14).

3. The electric steering column integrated speed reduction mechanism power assembly according to claim 1, characterized in that: The outer surface of the middle bearing (10) is symmetrically and evenly spaced with O-ring grooves (10-1), and an O-ring (10-2) is placed on the inner wall of the O-ring groove (10-1).

4. The electric steering column integrated speed reduction mechanism power assembly according to claim 1, characterized in that: A corrugated gasket (5) for eliminating axial clearance is provided between the end surface of the upper bearing (6) and the end cover.

5. The electric steering column integrated speed reduction mechanism power assembly according to claim 1, characterized in that: The bottom of the worm shaft (11) is provided with a thread (11-5), the outer surface of the thread (11-5) is sleeved with a threaded locking nut (15), and the upper surface of the locking nut (15) is in contact with the lower surface of the lower bearing (14).

6. The electric steering column integrated speed reduction mechanism power assembly according to claim 5, characterized in that: A tail cover nut (16) is threadedly connected through the bottom of the side wall of the speed reduction mechanism housing (13), and the tail cover nut (16) is sleeved on the outside of the locking nut (15).

7. The electric steering column integrated speed reduction mechanism power assembly according to claim 1, characterized in that: A PCBA board (2) is fixedly mounted on the upper surface of the upper cover (4), a magnetic ring (3) is abutted between the PCBA board (2) and the upper cover (4), and the magnetic ring (3) is sleeved on the top of the outer surface of the worm shaft (11).

8. The electric steering column integrated speed reduction mechanism power assembly according to claim 7, characterized in that: The upper surface of the upper cover (4) is riveted and fixedly connected to a top cover (1), and the top cover (1) is sleeved on the outside of the PCBA board (2).

Images