Multi-stage gear type all-electric power steering gear

Abstract

The invention relates to the field of steering gears, in particular to a multi-stage gear type all-electric power steering gear which comprises a steering mechanism which comprises a middle shell, a second-stage planet carrier arranged in the middle shell and an output shaft fixedly connected to the second-stage planet carrier. The first power mechanism comprises a core shaft assembly shell which is arranged at the left end of the middle shell and communicated with the middle shell, an input shaft is arranged on the core shaft assembly shell, and a first planet assembly and a second planet assembly which are used for providing power for rotation of an output shaft are arranged in the middle shell; a rotating component for providing assistance for the second planetary component is arranged in the core shaft assembly shell; the second power mechanism comprises a motor assembly shell which is arranged at the right end of the middle shell and communicates with the middle shell, when the device steers, through transmission of two sets of planetary gears and transmission of a worm gear and a worm, gear contact with a larger area is achieved, and therefore the device can bear higher torsion impact and cannot be damaged or broken.

Description

Technical Field

[0001] The present invention relates to the field of steering gears, in particular to a multi-stage gear type full electric power steering gear. Background Art

[0002] The electric power steering system is a power steering system that directly relies on the motor to provide auxiliary torque. Compared with the traditional hydraulic power steering system, the electric power steering system has many advantages. The electric power steering system is mainly composed of a torque sensor, a vehicle speed sensor, an electric motor, a reduction mechanism and an electronic control unit (ECU).

[0003] During use, the steering gear used in the vehicle uses a torque sensor to detect the torque of the steering wheel, and then controls the start of the motor, which drives the recirculating ball steering gear to steer (for large torque). In actual use, since it mainly relies on the rolling of the internal steel balls, it is necessary to ensure that the steel balls are sufficiently lubricated during the transmission process. Insufficient lubrication will cause friction between the rolling steel balls and the threads, which will cause wear of the steel balls, thereby affecting the service life of the recirculating ball steering gear. Although there is also a rack and pinion steering, the contact surface of this type is small and cannot be used for larger torques. Summary of the Invention

[0004] In view of the problem that the electric power-assisted recirculating ball steering gear mentioned above or in the prior art mainly relies on the rolling of the internal steel balls, it is necessary to ensure that the steel balls are sufficiently lubricated during the transmission process. If the lubrication is insufficient, the friction between the rolling of the steel balls and the threads will cause wear of the steel balls, thereby affecting the service life of the recirculating ball steering gear, the present invention is proposed.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: including a steering mechanism, including an intermediate housing, a secondary planetary carrier arranged in the intermediate housing, and an output shaft fixedly connected to the secondary planetary carrier; a first power mechanism, including a core shaft assembly housing arranged at the left end of the intermediate housing and connected to the intermediate housing, an input shaft is provided on the core shaft assembly housing, a first planetary assembly and a second planetary assembly that provide power for the rotation of the output shaft are provided in the intermediate housing, and a rotating assembly that provides power for the second planetary assembly is provided in the core shaft assembly housing; a second power mechanism, including a motor assembly housing arranged at the right end of the intermediate housing and connected to the intermediate housing, a power-assist motor is provided in the motor assembly housing, and the output end of the power-assist motor is provided with a transmission assembly that provides power for the first planetary assembly, and a control assembly for controlling the start of the power-assist motor is provided outside the core shaft assembly housing.

[0006] As a preferred solution of the multi-stage gear-type full-electric power steering device of the present invention, wherein: the first planetary assembly includes a first rotating shaft rotatably connected to the intermediate housing, a second large gear is fixedly connected to the first rotating shaft, a first sun gear is fixedly connected to the first rotating shaft, a first planetary carrier is provided on the upper side of the first sun gear, a second rotating shaft is fixedly connected to the first planetary carrier, and a first planetary gear meshing with the first sun gear is rotatably connected to the second rotating shaft.

[0007] As a preferred solution of the multi-stage gear-type full-electric power steering device of the present invention, the second planetary assembly includes a secondary sun gear fixedly connected to the primary planetary carrier, a secondary planetary carrier is provided on the upper side of the secondary sun gear, the secondary planetary carrier is fixedly connected to the output shaft, and a plurality of shafts are fixedly connected to the secondary planetary carrier, and the plurality of shafts are rotatably connected to secondary planetary gears that mesh with the secondary sun gear.

[0008] As a preferred solution of the multi-stage gear-type full-electric power steering device of the present invention, wherein: the secondary planetary carrier is provided with a sector plate fixedly connected thereto, and the intermediate housing is provided with a notch that cooperates with the sector plate.

[0009] As a preferred solution of the multi-stage gear-type full-electric power steering device of the present invention, wherein: a first ring gear and a second ring gear are fixedly connected in the intermediate housing, the first ring gear and the second ring gear are respectively engaged with the first-stage planetary gear and the second-stage planetary gear, and the first gear and the second gear are fixedly connected by multiple fixing columns.

[0010] As a preferred solution of the multi-stage gear-type full-electric power steering device of the present invention, the rotating assembly includes a torsion bar fixedly connected to the input shaft, the torsion bar is fixedly connected to a worm at one end away from the input shaft, and the secondary planetary carrier is fixedly connected to a worm wheel meshing with the worm.

[0011] As a preferred solution of the multi-stage gear-type full-electric power steering device of the present invention, wherein: the transmission assembly includes a first-stage pinion fixedly connected to the output end of the power-assisting motor, a support shaft is rotatably connected in the motor assembly housing, a first-stage large gear meshing with the first-stage pinion is fixedly connected to the support shaft, a second-stage pinion is fixedly connected to the first-stage large gear, the second-stage pinion is meshed with the second-stage large gear, the first-stage pinion and the second-stage pinion are both helical gears, and the first-stage pinion and the second-stage pinion are symmetrically arranged.

[0012] As a preferred solution of the multi-stage gear-type full-electric power steering device of the present invention, the control component includes an ECU controller fixedly connected to the core shaft assembly housing, the ECU controller cooperates with the torsion bar, and the motor assembly housing is provided with a start-stop controller for controlling the power-assisted motor.

[0013] Beneficial effects of the multi-stage gear-type all-electric power steering device of the present invention: 1. The present invention adopts the design of two sets of planetary gears, which has a larger gear contact area and 360-degree uniform load. Multiple gear surfaces jointly and evenly bear the instantaneous impact load, making it more able to withstand higher torque impact without damage or cracking. At the same time, the planetary reduction power steering device has a simple technical structure and a small number of parts. It does not need to consider sealing and high lubricity through gear transmission, and has lower maintenance costs and better reliability.

[0014] 2. By setting the first-stage pinion and the second-stage pinion as helical gears, during the transmission process, the first-stage pinion and the second-stage pinion are symmetrically arranged, the axial forces offset each other, reducing bearing wear and extending service life.

[0015] 3. By setting the worm gear to drive the second planetary carrier to move, and the power-assisting motor to drive the second planetary carrier to move, two control methods are realized, and the control is more stable. In addition, when the power-assisting motor is damaged, short-term steering control can still be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic diagram of the external structure of a multi-stage gear-type fully electric power steering device.

[0018] Figure 2 Schematic diagram of a multi-stage gear-type fully electric power steering system with the middle housing removed.

[0019] Figure 3 This is a schematic diagram of the external structure of the gear ring of a multi-stage gear-type full-electric power steering system.

[0020] Figure 4 This is a schematic diagram of the external structure of the first planetary assembly of a multi-stage gear-type fully electric power steering system.

[0021] Figure 5 This is an exploded view of the first and second planetary carriers of the multi-stage gear-type fully electric power steering system.

[0022] Figure 6 This is a schematic diagram of the cross-sectional structure of the intermediate housing of a multi-stage gear-type fully electric power steering system.

[0023] Figure 7 This is a schematic diagram of the external structure of the second planetary assembly of the multi-stage gear type full electric power steering.

[0024] Figure 8 This is a schematic diagram of the external structure of the sector plate of a multi-stage gear-type full electric power steering system.

[0025] Figure 9 This is a block diagram of the semi-redundant electronic control hardware system of a multi-stage gear-type full electric power steering system.

[0026] In the figure: 10, intermediate housing; 11, secondary planetary carrier; 12, output shaft; 20, core shaft assembly housing; 21, input shaft; 22, first planetary assembly; 221, first rotating shaft; 222, secondary large gear; 223, primary sun gear; 224, primary planetary carrier; 225, primary planetary gear; 23, second planetary assembly; 231, secondary sun gear; 232, secondary planetary gear; 233, sector plate; 234, notch; 235, first ring gear; 236, second ring gear; 237, fixing column; 24, rotating assembly; 241, torsion bar; 242, worm; 243, worm gear; 30, motor assembly housing; 31, power assist motor; 32, transmission assembly; 321, primary pinion; 322, primary large gear; 323, secondary pinion; 33, control assembly; 331, ECU controller; 332, start-stop controller. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] Reference Figures 1 to 8 A multi-stage gear-type full-electric power steering device includes a steering mechanism, including an intermediate housing 10, a secondary planetary carrier 11 arranged in the intermediate housing 10, and an output shaft 12 fixedly connected to the secondary planetary carrier 11; a first power mechanism, including a core shaft assembly housing 20 arranged at the left end of the intermediate housing 10 and communicated with the intermediate housing 10, an input shaft 21 is provided on the core shaft assembly housing 20, a first planetary assembly 22 and a second planetary assembly 23 for providing power for the rotation of the output shaft 12 are provided in the intermediate housing 10, and a rotating assembly 24 for providing power for the second planetary assembly 23 is provided in the core shaft assembly housing 20; a second power mechanism, including a motor assembly housing 30 arranged at the right end of the intermediate housing 10 and communicated with the intermediate housing 10, a power-assist motor 31 is provided in the motor assembly housing 30, and a transmission assembly 32 for providing power for the first planetary assembly 22 is provided at the output end of the power-assist motor 31, and a control assembly 33 for controlling the start of the power-assist motor 31 is provided outside the core shaft assembly housing 20.

[0029] Specifically, the output shaft 12 here is connected to the boom of the vehicle steering, and steering is performed by rotating the output shaft 12. The outer end of the input shaft 21 is connected to the converter, and the end of the converter is connected to the steering wheel. When the steering wheel rotates, the input shaft 21 rotates through transmission. The power-assisted motor 31 here can rotate forward and reverse. The power-assisted motor 31 here is existing technology and will not be described here.

[0030] Furthermore, the first planetary assembly 22 includes a first rotating shaft 221 rotatably connected to the intermediate housing 10, a secondary large gear 222 is fixedly connected to the first rotating shaft 221, a primary sun gear 223 is fixedly connected to the first rotating shaft 221, a primary planetary carrier 224 is provided on the upper side of the primary sun gear 223, a second rotating shaft is fixedly connected to the primary planetary carrier 224, and a primary planetary gear 225 meshing with the primary sun gear 223 is rotatably connected to the second rotating shaft; the second planetary assembly 23 includes a secondary sun gear 231 fixedly connected to the primary planetary carrier 224, a secondary planetary carrier 11 is provided on the upper side of the secondary sun gear 231, the secondary planetary carrier 11 is fixedly connected to the output shaft 12, a plurality of shaft bodies are fixedly connected to the secondary planetary carrier 11, and the plurality of shaft bodies are rotatably connected to secondary planetary gears 232 meshing with the secondary sun gear 231.

[0031] Among them, the first-level sun gear 223 and the second-level large gear 222 are arranged in the upper and lower positions, the first-level sun gear 223 is at the upper end of the second-level large gear 222, the second-level planetary gears 232 and the first-level planetary gears 225 are arranged in the upper and lower positions, and the multiple second-level planetary gears 232 and the multiple first-level planetary gears 225 are divided into two layers, and the multiple first-level planetary gears 225 are located on the lower side of the multiple second-level planetary gears 232.

[0032] Preferably, the secondary planetary carrier 11 is provided with a sector plate 233 fixedly connected, and the intermediate housing 10 is provided with a notch 234 that cooperates with the sector plate 233; the intermediate housing 10 is fixedly connected with a first ring gear 235 and a second ring gear 236, the first ring gear 235 and the second ring gear 236 are respectively engaged with the primary planetary gear 225 and the secondary planetary gear 232, and the first ring gear 235 and the second ring gear 236 are fixedly connected by a plurality of fixing columns 237; the rotating assembly 24 includes a torsion bar 241 fixedly connected to the input shaft 21, and the torsion bar 241 is fixedly connected to a worm 242 at one end away from the input shaft 21, and a worm wheel 243 engaged with the worm 242 is fixedly connected to the secondary planetary carrier 11.

[0033] It should be noted that the first-stage planetary gear 225 is meshed with the first-stage sun gear 223 and the first ring gear 235. When the first-stage sun gear 223 rotates, it will drive multiple first-stage planetary gears 225 to rotate around the first-stage sun gear 223. The first ring gear 235 and the second ring gear 236 here are both inner ring gears. A protrusion is provided on the intermediate housing 10, and a groove that matches the protrusion is provided on the outer side wall of the first ring gear 235 and the second ring gear 236. The protrusion and the groove cooperate to prevent the first ring gear 235 and the second ring gear 236 from self-rotating.

[0034] Furthermore, the transmission assembly 32 includes a first-stage pinion 321 fixedly connected to the output end of the power-assisting motor 31, a support shaft is rotatably connected in the motor assembly housing 30, a first-stage large gear 322 is fixedly connected to the support shaft and meshed with the first-stage pinion 321, a second-stage pinion 323 is fixedly connected to the first-stage large gear 322, and the second-stage pinion 323 meshes with the second-stage large gear 222; the control assembly 33 includes an ECU controller 331 fixedly connected to the core shaft assembly housing 20, the ECU controller 331 cooperates with the torsion bar 241, and a torque sensor is integrated in the ECU controller 331 for detecting the rotation of the torsion bar 241 (this is the existing technology and will not be described in detail here). The motor assembly housing 30 is provided with a start-stop controller 332 for controlling the power-assisting motor 31.

[0035] It is worth noting that there is a buffer pad between the four claws of the power-boosting motor 31 (the four claws are also called the stator or stator of the power-boosting motor 31) and the first-stage pinion 321. Its function is that when the power-boosting motor 31 is running, a sudden stop will generate inertia and recoil force inside the power-boosting motor 31, causing impact and damage to the internal components of the power-boosting motor 31. The buffer of the power-boosting motor 31 can reduce the possibility of the power-boosting motor 31 stopping suddenly, thereby reducing damage to the internal components of the power-boosting motor 31 and extending the life of the power-boosting motor 31.

[0036] During use, the steering wheel rotates through the transmission to deflect the input shaft 21, and the output shaft 12 rotates to rotate the worm 242, thereby rotating the worm 242, driving the secondary planetary carrier 11 to deflect, causing the output shaft 12 to rotate, deflecting the boom, and realizing steering. When steering, the fan-shaped plate 233 on the secondary planetary carrier 11 cooperates with the notch 234 to limit the rotation angle of the secondary planetary carrier 11, avoid oversteering, and ensure steering stability. It is worth noting that the steering wheel is not directly fixed to the input shaft 21, and a converter is provided in the middle, so that the deflection angle of the steering wheel will be larger than that of the secondary planetary carrier 11, which will not affect the steering wheel.

[0037] When the input shaft 21 rotates, the torsion bar 241 deflects. The amount of rotation of the torsion bar 241 reflects the required rotation angle. At this time, the sensor detects the deflection and feeds it back to the ECU. The controller then controls the power-assist motor 31 to rotate through the start-stop controller 332. The power-assist motor 31 provides an output torque of appropriate size. The output end of the power-assist motor 31 rotates to drive the first-stage pinion 321 to rotate, so that the first-stage large gear 322 meshing with the first-stage pinion 321 rotates, thereby supporting the shaft to rotate, driving the second-stage pinion 323 to rotate, so that the second-stage large gear 222 meshing with the second-stage pinion 323 rotates. It is worth noting that the number of teeth of the first-stage pinion 321 here is less than that of the first-stage large gear 322, and the number of teeth of the second-stage pinion 323 is less than that of the second-stage large gear 222. Therefore, when the output end of the power-assist motor 31 rotates, it is always decelerating. Since there is a negative correlation between the torque and the speed of the power-assist motor 31, sufficient torque is guaranteed for transmission during deceleration. The first-stage pinion 321 and the second-stage pinion 323 here are both helical gears. At the same time, the two helical gears are symmetrically designed, and the axial forces offset each other, reducing bearing wear and improving service life.

[0038] Since the primary sun gear 223 is fixed to the secondary large gear 222, the primary sun gear 223 rotates, driving multiple primary planetary gears 225 to rotate around the primary sun gear 223, driving the primary planetary carrier 224 to rotate. Since the secondary sun gear 231 is fixed to the primary planetary carrier 224, the secondary sun gear 231 rotates, causing multiple secondary planetary gears 232 to rotate, and the secondary planetary carrier 11 to rotate. Since the output shaft 12 is fixed to the secondary planetary carrier 11, the rotation of the output end of the power-assist motor 31 can also drive the output shaft 12 to rotate. The secondary planetary carrier 11 is driven to rotate by the rotation of the turbine and the rotation of the output shaft 12 of the power-assist motor 31, making steering more labor-saving. It is worth noting that the above method uses the primary planetary gear 225 and the secondary planetary gear 232 to perform the transmission rod. Its advantage is that it has a larger area of ​​gear contact, 360-degree uniform load, and multiple gear surfaces jointly and evenly bear the instantaneous impact load, making it more able to withstand higher torque impacts without being damaged or broken.

[0039] Reference Figure 9 The present invention also designs a semi-redundant solution for use with the ECU controller, as follows: The ECU controller 331 adopts a semi-redundant solution, and its internal components are a single PMIC, a single MCU, a single CAN transceiver, a dual MOSFET pre-driver chip, and a dual three-phase MOSFET full-bridge. The MCU chip and the MOSFET pre-driver chip determine the status of the two sets of motor drive circuits through SPI communication, thereby realizing the switching of the two sets of power-assisting motor 31 drive circuits; the sensor supporting the ECU controller 331 is designed as a redundant sensor, and its internal sensor has two independent 5V power supply networks, as well as two independent torque detection circuits. Each detection circuit outputs two independent torque control signals; dual-winding motor: There are two completely independent windings, which act on a rotor together. Each winding has an independent phase line terminal. If a winding circuit fails, the other winding can provide 50% of the rated torque of the power-assisting motor 31.

[0040] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A multi-stage gear type fully electric power steering, characterized by: include, A steering mechanism comprising an intermediate housing (10), a secondary planetary carrier (11) disposed within the intermediate housing (10), and an output shaft (12) fixedly connected to the secondary planetary carrier (11); The first power mechanism comprises a core shaft assembly housing (20) arranged at the left end of the intermediate housing (10) and in communication with the intermediate housing (10), an input shaft (21) being provided on the core shaft assembly housing (20), a first planetary assembly (22) and a second planetary assembly (23) being provided in the intermediate housing (10) for providing power for the rotation of the output shaft (12), and a rotating assembly (24) being provided in the core shaft assembly housing (20) for providing power for the second planetary assembly (23); The second power mechanism comprises a power-assisting motor (31) assembly housing (30) disposed at the right end of the intermediate housing (10) and connected to the intermediate housing (10), wherein the power-assisting motor (31) assembly housing (30) is provided with a power-assisting motor (31), an output end of the power-assisting motor (31) is provided with a transmission assembly (32) for providing power to the first planetary assembly (22), and a control assembly (33) for controlling the start-up of the power-assisting motor (31) is provided outside the spindle assembly housing (20).

2. The multi-stage gear type full electric power steering device according to claim 1, characterized in that: The first planetary assembly (22) comprises a first rotating shaft (221) rotatably connected to the intermediate housing (10); a second large gear (222) is fixedly connected to the first rotating shaft (221); a first sun gear (223) is fixedly connected to the first rotating shaft (221); a first planet carrier (224) is provided on the upper side of the first sun gear (223); a second rotating shaft is fixedly connected to the first planet carrier (224); and a first planet gear (225) meshing with the first sun gear (223) is rotatably connected to the second rotating shaft.

3. The multi-stage gear type full electric power steering device according to claim 2, characterized in that: The second planetary assembly (23) includes a secondary sun gear (231) fixedly connected to the primary planetary frame (224), a secondary planetary frame (11) is provided on the upper side of the secondary sun gear (231), the secondary planetary frame (11) is fixedly connected to the output shaft (12), and a plurality of shafts are fixedly connected to the secondary planetary frame (11), and the plurality of shafts are rotatably connected to secondary planetary gears (232) meshing with the secondary sun gear (231).

4. The multi-stage gear type full electric power steering device according to claim 3, characterized in that: The secondary planet carrier (11) is provided with a sector plate (233) fixedly connected thereto, and the intermediate housing (10) is provided with a notch (234) that cooperates with the sector plate (233).

5. The multi-stage gear type full electric power steering device according to claim 4, characterized in that: A first ring gear (235) and a second ring gear (236) are fixedly connected in the intermediate housing (10); the first ring gear (235) and the second ring gear (236) are respectively engaged with the first-stage planetary gear (225) and the second-stage planetary gear (232); the first ring gear (235) and the second ring gear (236) are fixedly connected via a plurality of fixing columns (237).

6. The multi-stage gear type full electric power steering device according to claim 5, characterized in that: The rotating assembly (24) comprises a torsion bar (241) fixedly connected to the input shaft (21); one end of the torsion bar (241) away from the input shaft (21) is fixedly connected to a worm (242); and a worm wheel (243) meshing with the worm (242) is fixedly connected to the secondary planet carrier (11).

7. The multi-stage gear type full electric power steering according to claim 5 or 6, characterized in that: The transmission assembly (32) includes a first-stage pinion (321) fixedly connected to the output end of the power-assisting motor (31); a support shaft is rotatably connected in the assembly housing (30) of the power-assisting motor (31); a first-stage large gear (322) meshing with the first-stage pinion (321) is fixedly connected to the support shaft; a second-stage pinion (323) is fixedly connected to the first-stage large gear (322); the second-stage pinion (323) meshes with the second-stage large gear (222); the first-stage pinion (321) and the second-stage pinion (323) are both helical gears, and the first-stage pinion (321) and the second-stage pinion (323) are symmetrically arranged.

8. The multi-stage gear type full electric power steering device according to claim 7, characterized in that: The control assembly (33) includes an ECU controller (331) fixedly connected to the core shaft assembly housing (20), the ECU controller (331) cooperates with the torsion bar (241), and the power-assist motor (31) assembly housing (30) is provided with a start-stop controller (332) for controlling the power-assist motor (31).

Images