Large output torque electric power steering device for commercial vehicle

Abstract

The invention relates to the technical field of automobile steering devices, in particular to a large-output-torque electric power steering device for a commercial vehicle, which comprises a speed reducer shell and a steering gear shell which are fastened together, a planetary speed reducing mechanism is mounted in the speed reducer shell, and a worm and gear transmission mechanism is mounted in the steering gear shell. The power output ends of the planetary reducing mechanism and the worm and gear transmission mechanism are respectively connected with a sun gear output shaft; a power transmission mechanism connected with a power output shaft of the motor is installed on the input shaft end cover, and the power transmission mechanism is connected with the planetary speed reduction mechanism. The motor is connected with a motor controller, the motor controller is in signal connection with an electronic control unit, and the electronic control unit is in signal connection with a torque sensor of the vehicle; the speed reducer is small in size, light in weight, large in transmission ratio, high in output torque, low in energy consumption, high in reliability, small in part number and convenient to arrange, the number of parts is small, and the running performance and fuel economy of an automobile are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile steering devices, in particular to a large-output-torque electric power-assisted steering device for commercial vehicles. BACKGROUND

[0002] In the current automobile manufacturing industry, large-tonnage trucks and commercial vehicles are widely used in various fields such as logistics and transportation due to their high load capacity and high efficiency. However, with the increasing strictness of environmental regulations and the growing demand for high-performance vehicles, the current mainstream structure of commercial vehicles in China is still the pure hydraulic ball structure. The hydraulic power steering system requires a large number of parts such as power steering oil pumps, hoses, hydraulic oil, belts, and pulleys mounted on the engine, which are complicated to arrange, heavy in weight, and not only waste energy but also are not conducive to environmental protection. In addition, there are parasitic losses and liquid leakage losses. Currently, there is a lack of steering gears that can better adapt to high power consumption and high steering assistance demand.

[0003] A high-performance electric power-assisted steering gear will significantly improve the maneuverability and stability of commercial vehicles, reduce the risk of traffic accidents caused by steering system failures, and provide safer driving protection for drivers and passengers. The design of large transmission ratio and high output torque will enable commercial vehicles to maintain excellent steering performance under heavy load and high torque conditions, improving the transportation efficiency and economic benefits of vehicles. The low-energy design will help reduce the fuel consumption and emissions of commercial vehicles, meet the requirements of environmental regulations, and promote the development of green transportation.

[0004] Therefore, it is necessary to design a large-ratio electric power-assisted steering gear for large-tonnage trucks and commercial vehicles, which can significantly improve the performance of commercial vehicles, reduce energy consumption, and enhance driving safety. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a large-output-torque electric power-assisted steering device for commercial vehicles with small size, light weight, large transmission ratio, high output torque, low energy consumption, and high reliability.

[0006] To solve the above technical problems, the technical solution of the present application is: a large-output-torque electric power-assisted steering device for commercial vehicles, comprising a reducer housing and a steering gear housing that are installed together, a planetary reduction mechanism is installed in the reducer housing, a worm gear transmission mechanism is installed in the steering gear housing, a sun gear output shaft is connected to the power output end of the planetary reduction mechanism and the power output end of the worm gear transmission mechanism, respectively, and the sun gear output shaft is connected to the steering rocker arm of the vehicle.

[0007] The motor is further provided with an input shaft end cover installed between the motor housing and the speed reducer housing, a power transmission mechanism connected with the power output shaft of the motor is installed on the input shaft end cover, and the power transmission mechanism is connected with the planetary speed reduction mechanism;

[0008] The motor is further provided with a motor controller, the motor controller is signal connected with an electronic control unit, and the electronic control unit is signal connected with a torque sensor of the vehicle.

[0009] As a preferred technical solution, the speed reducer housing comprises a cylindrical housing, one end of the cylindrical housing is open, the other end of the cylindrical housing is closed through an end cover, the outside of the center of the end cover is provided with the sun gear output shaft through a bearing, the inside of the center of the end cover is integrally provided with a Z1 gear shaft, the sun gear output shaft passes through the shaft hole of the Z1 gear shaft, and the two ends of the cylindrical housing are respectively provided with mounting flanges.

[0010] As a preferred technical solution, the planetary speed reduction mechanism is a two-stage planetary reducer, the sun gear of the two-stage planetary reducer comprises the sun gear output shaft and the Z1 gear shaft fixedly installed on the speed reducer housing, the planetary gears of the two-stage planetary reducer comprise Z2 planetary gears meshing with the sun gear output shaft, Z2' planetary gears meshing with the Z1 gear shaft, and Z4 planetary gear carriers meshing with the power transmission mechanism.

[0011] As a preferred technical solution, the shaft center of the input shaft end cover is provided with a shaft coupling accommodating cavity close to the motor, the shaft center of the input shaft end cover is provided with an end cover stepped hole away from the motor, the Z7 gear shaft is installed in the end cover stepped hole through a bearing, and two support shafts are further installed on the shaft center of the input shaft end cover away from the motor, and the two support shafts are symmetrically arranged with the shaft line of the input shaft end cover as the center.

[0012] As a preferred technical solution, the power transmission mechanism comprises a shaft coupling connected with the power output shaft of the motor, the shaft coupling is located in the shaft coupling accommodating cavity, the shaft coupling is fixedly connected with the Z7 gear shaft, Z6 gears are respectively installed on the two support shafts, the Z7 gear shaft is meshed with the two Z6 gears, and the Z6 gears are further meshed with the Z4 planetary gear carriers.

[0013] As a preferred technical solution, the input torque is transmitted to the shaft coupling through the motor, the shaft coupling is transmitted to the Z7 gear shaft, the Z6 gears are transmitted to the Z4 planetary gear carriers, the Z2 planetary gears and the Z2' planetary gears are further transmitted to the sun gear output shaft, and the sun gear output shaft outputs the torque.

[0014] As a preferred technical scheme, the worm gear transmission mechanism comprises a worm connected with the steering shaft, and a sector worm engaged with the worm.

[0015] As a preferred technical scheme, the steering gear housing comprises a worm housing cavity and a worm housing cavity, one end of the worm housing cavity is open, a through hole is formed in the other end of the worm housing cavity for the sun gear output shaft to pass out, one end of the worm housing cavity is sealed by a compression plug, the other end of the worm housing cavity is sealed by a steering shaft cover, and both ends of the worm are respectively installed in the worm housing cavity through bearings.

[0016] As a preferred technical scheme, the steering shaft is internally installed with a torsion bar.

[0017] As a preferred technical scheme, the open end of the worm housing cavity is provided with a mounting flange for cooperation with the reducer housing.

[0018] Due to the above technical scheme, the large output torque electric power steering device for commercial vehicles comprises a reducer housing and a steering gear housing which are snap-fitted together, a planetary reduction mechanism is installed in the reducer housing, a worm gear transmission mechanism is installed in the steering gear housing, a sun gear output shaft is connected to the power output end of the planetary reduction mechanism and the power output end of the worm gear transmission mechanism, respectively, and the sun gear output shaft is connected with the steering rocker arm of the vehicle; further comprising a motor, an input shaft end cover is installed between the motor housing and the reducer housing, a power transmission mechanism connected with the power output shaft of the motor is installed on the input shaft end cover, the power transmission mechanism is connected with the planetary reduction mechanism; the motor is connected with a motor controller, the motor controller is signal connected with an electronic control unit, and the electronic control unit is signal connected with a torque sensor of the vehicle; the beneficial effects of the present application are: when the driver operates the steering wheel to steer, the torque sensor detects the steering and torque of the steering wheel, and sends the voltage signal to the electronic control unit, the electronic control unit sends instructions to the motor controller according to the torque voltage signal, the rotation direction and the vehicle speed signal detected by the torque sensor, so that the motor outputs the corresponding size and direction of the steering assist torque, thereby generating auxiliary power. When the automobile is not steering, the electronic control unit does not send instructions to the motor controller, and the motor does not work. That is, the electronic control unit (ECU) determines the rotation direction and the best assist torque of the motor according to the signal output by the torque sensor, sends control signals to the motor and the clutch, controls the rotation of the direct current motor through the power drive circuit, the output of the motor is reduced and the torque is increased after the planetary reduction mechanism, a two-stage planetary reducer with a larger transmission ratio is used, the worm gear transmission mechanism is used, the input large torque is reduced, and the transmission efficiency of the transmission system is increased.

[0019] The application provides a large-torque output on the basis of a large transmission ratio realized by a planetary gear set, and a human-powered steering device composed of a worm gear transmission mechanism to form a whole steering system, which is a relatively high-quality scheme for realizing large-torque output, reduces the input torque through the planetary gear with a large transmission ratio, and directly provides steering assistance by the motor torque. The application provides an electric power steering device with the advantages of a large transmission ratio, high output torque, low energy consumption, high reliability, etc. The high-performance electric power steering device will significantly improve the maneuverability and stability of commercial vehicles, reduce the risk of traffic accidents caused by steering system failures, and provide safer driving protection for drivers and passengers. The design of a large transmission ratio and high output torque will enable commercial vehicles to maintain excellent steering performance under heavy load and high torque conditions, improving the transportation efficiency and economic benefits of vehicles. The low energy consumption design will help reduce the fuel consumption and emissions of commercial vehicles, meet the requirements of environmental protection regulations, and promote the development of green transportation. The application has flexible arrangement, high transmission efficiency, and the output of the motor is reduced and increased in torque after passing through the planetary reduction mechanism, driving the worm gear transmission mechanism to generate large steering assistance. Compared with mechanical hydraulic power steering devices, the electric power steering device only needs electricity and does not use hydraulic pressure, which eliminates many components. There is no oil pump, oil pipe, pressure flow control valve, oil tank, etc. required by the hydraulic system, the number of parts is small, the arrangement is convenient, and the weight is light. Moreover, there is no parasitic loss and liquid leakage loss. Therefore, the electric power steering system of the application can save about 80% of energy under various driving conditions, improve the operating performance and fuel economy of the vehicle, and meet the needs of large vehicle steering devices in all aspects. BRIEF DESCRIPTION OF DRAWINGS

[0020] The following drawings are only intended to illustrate and explain the application and do not limit the scope of the application. Among them:

[0021] Figure 1 is a perspective view of the large output torque electric power steering device for commercial vehicles according to the application;

[0022] Figure 2 is a C view in Figure 1 ;

[0023] Figure 3 is a D view in Figure 1 ;

[0024] Figure 4 is a B-B sectional view in Figure 3 ;

[0025] Figure 5 is a partial structure diagram of the large output torque electric power steering device for commercial vehicles according to the application;

[0026] Figure 6 is an E view in Figure 5 ;

[0027] Figure 7 is the second partial structural schematic diagram of the high-torque electric power steering device for commercial vehicles of the present application;

[0028] Figure 8 is Figure 2 is the sectional view of A-A direction in

[0029] Figure 9 is the structural schematic diagram of the steering gear housing of the present application;

[0030] Figure 10 is the structural schematic diagram of the reducer housing of the present application;

[0031] Figure 11 is the structural schematic diagram of the input shaft end cover of the present application;

[0032] Figure 12 is the sectional view of the input shaft end cover of the present application;

[0033] Figure 13 is the structural schematic diagram of the Z7 gear shaft of the present application;

[0034] Figure 14 is the structural schematic diagram of the sun gear output shaft of the present application;

[0035] Figure 15 is the structural schematic diagram of the Z4 planet carrier of the present application.

[0036] In the figure: 1-motor; 2-input shaft end cover; 21-coupling accommodating cavity; 22-end cover stepped hole; 23-Z7 gear shaft; 24-supporting shaft; 25-coupling; 26-Z6 gear; 3-reducer housing; 31-Z2' planetary gear; 32-Z4 planet carrier; 33-Z1 gear shaft; 34-sun gear output shaft; 35-Z2 planetary gear; 4-steering gear housing; 41-worm accommodating cavity; 42-worm accommodating cavity; 43-pressing screw plug; 44-steering shaft cover; 45-worm; 46-segmented worm; 47-torsion bar; 48-steering shaft. DETAILED DESCRIPTION

[0037] The present application is further described below in conjunction with the accompanying drawings and examples. In the following detailed description of the application, certain exemplary embodiments of the application are described by way of illustration only. It will be apparent to those skilled in the art that the embodiments described can be modified in various ways without departing from the spirit and scope of the application. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0038] As Figures 1 to 15The utility model discloses a high-torque electric power steering device for commercial vehicle, which comprises a reducer housing 3 and a steering housing 4 that are buckled together, a planetary reducer mechanism is installed in the reducer housing 3, a worm gear transmission mechanism is installed in the steering housing 4, a sun gear output shaft 34 is connected to the power output end of the planetary reducer mechanism and the power output end of the worm gear transmission mechanism respectively, and the sun gear output shaft 34 is connected to the steering rocker arm of the vehicle; the utility model also comprises a motor 1, an input shaft end cover 2 is installed between the motor housing of the motor 1 and the reducer housing 3, a power transmission mechanism connected to the power output shaft of the motor 1 is installed on the input shaft end cover 2, the power transmission mechanism is connected to the planetary reducer mechanism; the motor 1 is connected to a motor controller, the motor controller is connected to an electronic control unit, and the electronic control unit is connected to the torque sensor of the vehicle; when the driver steers the steering wheel, the torque sensor detects the steering and torque of the steering wheel, sends a voltage signal to the electronic control unit, and the electronic control unit sends an instruction to the motor controller according to the torque voltage signal, the rotation direction and the vehicle speed signal detected by the torque sensor, so that the motor 1 outputs a corresponding size and direction of steering assist torque, thereby generating auxiliary power. When the vehicle is not steering, the electronic control unit does not send an instruction to the motor controller, and the motor 1 does not work. That is, the electronic control unit (ECU) determines the rotation direction and the optimal assist torque of the motor 1 according to the signal output by the torque sensor, sends a control signal to the motor 1 and the clutch, controls the rotation of the direct current motor 1 through the power driving circuit, the output of the motor 1 is reduced and the torque is increased after the planetary reducer mechanism, a two-stage planetary reducer with a large transmission ratio is used, the worm gear transmission mechanism is used, the input large torque is reduced, and the transmission efficiency of the transmission system is increased.

[0039] The application provides a large torque output on the basis of a large transmission ratio realized by a planetary gear set, and a human-powered steering gear composed of a worm gear transmission mechanism to form the entire steering system, which is a relatively high-quality scheme for realizing a large torque output, reduces the input torque through the planetary gear with a large transmission ratio, and directly provides steering assistance by the motor 1 torque. The application provides an electric power steering gear with the advantages of a large transmission ratio, high output torque, low energy consumption, high reliability, etc. The high-performance electric power steering gear will significantly improve the maneuverability and stability of commercial vehicles, reduce the risk of traffic accidents caused by steering system failures, and provide safer driving protection for drivers and passengers. The design of a large transmission ratio and high output torque will enable commercial vehicles to maintain excellent steering performance under heavy load and high torque conditions, improving the transportation efficiency and economic benefits of the vehicle. The low energy consumption design will help reduce the fuel consumption and emissions of commercial vehicles, meet environmental regulations, and promote the development of green transportation. The application has flexible arrangement, high transmission efficiency, and the output of the motor 1 is reduced and increased in torque after passing through the planetary reduction mechanism, driving the worm gear transmission mechanism to generate large steering assistance. Compared with mechanical hydraulic power steering gears, the electric power steering gear only needs electricity and omits many elements. There is no oil pump, oil pipe, pressure flow control valve, oil tank, etc. required by the hydraulic system, the number of parts is small, the arrangement is convenient, and the weight is light. Moreover, there is no parasitic loss and liquid leakage loss. Therefore, the electric power steering system of the application can save about 80% of energy under various driving conditions, improve the operating performance and fuel economy of the vehicle, and meet the various needs of large vehicle steering gears.

[0040] As Figure 1 , Figure 2 , Figure 4 and Figure 10 shown, the reducer housing 3 includes a cylindrical housing, one end of the cylindrical housing is open, the other end of the cylindrical housing is closed by an end cover, the outside of the center of the end cover is installed with a sun gear output shaft 34 through a bearing, the inside of the center of the end cover is integrally provided with a Z1 gear shaft 33, the sun gear output shaft 34 passes through the shaft hole of the Z1 gear shaft 33, and the two ends of the cylindrical housing are respectively provided with mounting flanges. The size of the cylindrical housing is matched with the size of the worm gear containing cavity 41 of the steering gear housing 4, and the two are relatively buckled together and then fixed and connected through a sealing gasket and bolts. The mounting flange provides space for the installation of bolts, the Z1 gear shaft 33 is engaged with the Z2' planetary gear 31 as a sun gear, and the end cover provides axial positioning for the sun gear output shaft 34.

[0041] As Figures 4 to 8As shown in the figures, the planetary speed reducer is a two-stage planetary reducer, the sun gear of the two-stage planetary reducer includes a sun gear output shaft 34 and a Z1 gear shaft 33 fixedly installed on the reducer housing 3, the planetary gear of the two-stage planetary reducer includes a Z2 planetary gear 35 meshing with the sun gear output shaft 34, a Z2' planetary gear 31 meshing with the Z1 gear shaft 33, and a Z4 planetary carrier 32 meshing with the power transmission mechanism. The two-stage planetary reducer is a prior art, and its structure and working principle are not described here.

[0042] As shown in the figures, Figure 4 , Figure 11 , Figure 12 and Figure 13 As shown in the figures, the shaft center of the input shaft end cover 2 is provided with a shaft coupling accommodating cavity 21 near the side of the motor 1, and the shaft center of the input shaft end cover 2 is provided with an end cover stepped hole 22 away from the side of the motor 1, the Z7 gear shaft 23 is installed in the end cover stepped hole 22 through a bearing, and two support shafts 24 are installed on the shaft center of the input shaft end cover 2 away from the side of the motor 1, and the two support shafts 24 are symmetrically arranged with the axis of the input shaft end cover 2 as the center. The shaft coupling accommodating cavity 21 is a cylindrical cavity for providing space for the installation of the shaft coupling 25, and the end cover stepped hole 22 provides space for the installation of the Z7 gear shaft 23 for fixing the Z7 gear shaft 23. The two support shafts 24 are used to install the Z6 gear 26, and the Z6 gear 26 is used to drive the planetary speed reducer.

[0043] As shown in the figures, Figures 4 to 7 The power transmission mechanism includes a shaft coupling 25 connected with the power output shaft of the motor 1, the shaft coupling 25 is located in the shaft coupling accommodating cavity 21, the shaft coupling 25 is fixedly connected with the Z7 gear shaft 23, the shaft coupling 25 transmits power from the motor 1 to the Z7 gear shaft 23, the two support shafts 24 are respectively provided with Z6 gears 26, the Z7 gear shaft 23 is meshed with the two Z6 gears 26, the Z6 gears 26 rotate in the reducer housing 3, and the Z6 gears 26 are also meshed with the Z4 planetary carrier 32.

[0044] As shown in the figures, Figures 4 to 7 The input torque is transmitted to the shaft coupling 25 through the motor 1, the shaft coupling 25 transmits the torque to the Z7 gear shaft 23, the Z6 gears 26 transmit the torque to the Z4 planetary carrier 32, and the Z2 planetary gear 35 and the Z2' planetary gear 31 transmit the torque to the sun gear output shaft 34, and the sun gear output shaft 34 outputs the torque.

[0045] As shown in the figures, Figure 1 , Figure 2 , Figure 4 and Figure 9As shown in the drawings, the steering gear housing 4 comprises a worm gear accommodating cavity 41 and a worm accommodating cavity 42, which are integrally arranged and connected through each other, the worm gear accommodating cavity 41 is open at one end, a through hole is arranged at the other end of the worm gear accommodating cavity 41 for the sun gear output shaft 34 to pass through, the worm accommodating cavity 42 is sealed at one end by a compression plug 43, and the other end is sealed by a steering shaft cover 44, and the two ends of the worm 45 are respectively installed in the worm accommodating cavity 42 through bearings.

[0046] As shown in the drawings, Figures 4 to 8 As shown in the drawings, the worm gear and worm drive mechanism comprises a worm 45 connected with the steering shaft 48, the worm 45 is engaged with a sector worm gear 46, and the worm shaft sleeve of the sector worm gear 46 is in interference fit with the sun gear output shaft 34. When the worm 45 drives the sector worm gear 46 to move, the sector worm gear 46 transmits torque to the sun gear output shaft 34 due to the interference fit with the sun gear output shaft 34.

[0047] As shown in the drawings, Figure 8 As shown in the drawings, a torsion bar 47 is installed in the steering shaft 48. The steering shaft 48 and the torsion bar 47 are different functional components in the automobile steering system, and are respectively responsible for transmitting steering torque and suppressing body roll. The steering shaft 48 is a core component connecting the steering wheel and the steering gear, and mainly functions to transmit the steering torque applied by the driver. The upper end is fixed with the steering wheel, and the lower end is connected with the steering gear, supported through bearings and bushings in the steering column, to realize the transmission of steering force. The torsion bar 47 is an elastic element in the suspension system, used to resist body roll. When the vehicle turns, the torsion bar 47 generates a counterforce through its torsional elasticity, keeping the height of the vehicle body balanced left and right, and improving the ride comfort.

[0048] As shown in the drawings, Figure 9 As shown in the drawings, the open end of the worm gear accommodating cavity 41 is provided with a mounting flange for cooperation with the reducer housing 3. The mounting flange provides space for bolt installation.

[0049] The present application has the following advantages:

[0050] The driving motor 1 is used as input, the Z4 planetary gear carrier 32 drives the sun gear output shaft 34, the sector worm gear 46 is used as output, the worm 45 is connected with the motor 1, and the steering valve and the motor 1 are controlled by sensing the driver's steering intention and generating corresponding electric signals to utilize electric energy, so as to realize the control of vehicle steering.

[0051] The present application is flexible in arrangement and high in transmission efficiency, the output of the motor 1 is reduced in speed and increased in torque through the planetary reduction mechanism, then drives the worm gear transmission mechanism to generate large steering assist force, since the electric power steering gear only needs electric power and does not need hydraulic pressure, compared with the mechanical hydraulic power steering gear, many elements are omitted, such as oil pump, oil pipe, pressure flow control valve, oil tank and the like, the number of parts is less, the arrangement is convenient, and the weight is light, and there is no "parasitic loss" and liquid leakage loss, therefore, the present application can save energy by about 80% under various driving conditions, improves the running performance and fuel economy of the automobile, and meets the various needs of the steering gear of large automobile.

[0052] When the driver steers the steering wheel, the torque sensor detects the steering of the steering wheel and the size of the torque, and sends a voltage signal to the electronic control unit, the electronic control unit sends instructions to the motor controller according to the torque voltage signal, the rotation direction and the vehicle speed signal detected by the torque sensor, so that the motor 1 outputs a corresponding size and direction of steering assist torque, thereby generating auxiliary power. When the automobile is not steering, the electronic control unit does not send instructions to the motor controller, and the motor 1 does not work. That is, the electronic control unit (ECU) determines the rotation direction and the optimal assist torque of the motor 1 according to the signal output by the torque sensor, sends control signals to the motor 1 and the clutch, controls the rotation of the direct current motor 1 through the power drive circuit, the output of the motor 1 is reduced in speed and increased in torque through the planetary reduction mechanism, a two-stage planetary reducer with a larger transmission ratio is used, and the worm gear transmission mechanism is used to reduce the input large torque, so that the transmission efficiency of the transmission system is increased.

[0053] The present application will be oriented to market demand and driven by technological innovation, continuously promote the research and development and implementation of the project, and contribute to the development and progress of the commercial vehicle industry.

[0054] In the present application, the technical features related to software and circuit program are within the prior art, the essence of the technical solution of the present application is to improve the composition and connection relationship of the hardware part, and does not involve the improvement of the software program or circuit structure itself.

[0055] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application.

[0056] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A high-torque electric power steering device for a commercial vehicle, characterized by: The reducer housing (3) and the diverter housing (4) are snap-fitted together, the planetary reducer mechanism is installed in the reducer housing (3), the worm gear transmission mechanism is installed in the diverter housing (4), the power output end of the planetary reducer mechanism and the power output end of the worm gear transmission mechanism are respectively connected with the sun gear output shaft (34), and the sun gear output shaft (34) is connected with the steering rocker arm of the vehicle; The motor (1) is further provided, the motor housing and the reducer housing (3) are provided with an input shaft end cover (2), the input shaft end cover (2) is provided with a power transmission mechanism connected with the power output shaft of the motor (1), and the power transmission mechanism is connected with the planetary reducer mechanism. The motor (1) is connected with a motor controller, the motor controller is connected with an electronic control unit, and the electronic control unit is connected with a torque sensor of the vehicle.

2. The high-torque electric power steering apparatus for a commercial vehicle of claim 1, characterized in that: The reducer housing (3) comprises a cylindrical housing, one end of the cylindrical housing is open, the other end of the cylindrical housing is closed through an end cover, the outside of the center of the end cover is provided with the sun gear output shaft (34) through a bearing, the inside of the center of the end cover is integrally provided with a Z1 gear shaft (33), the sun gear output shaft (34) penetrates the shaft hole of the Z1 gear shaft (33), and the two ends of the cylindrical housing are respectively provided with mounting flanges.

3. The high-torque electric power steering apparatus for a commercial vehicle of claim 2, characterized in that: The planetary reducer mechanism is a two-stage planetary reducer, the sun gear of the two-stage planetary reducer comprises the sun gear output shaft (34) and the Z1 gear shaft (33) fixedly installed on the reducer housing (3), the planetary gear of the two-stage planetary reducer comprises a Z2 planetary gear (35) engaged with the sun gear output shaft (34), a Z2' planetary gear (31) engaged with the Z1 gear shaft (33) and a Z4 planetary gear carrier (32) engaged with the power transmission mechanism.

4. The high-torque electric power steering apparatus for a commercial vehicle of claim 3, characterized in that: The shaft center of the input shaft end cover (2) is provided with a shaft coupling accommodating cavity (21) close to one side of the motor (1), the shaft center of the input shaft end cover (2) is provided with an end cover stepped hole (22) away from the other side of the motor (1), the Z7 gear shaft (23) is installed in the end cover stepped hole (22) through a bearing, and two support shafts (24) are further installed on the shaft center of the input shaft end cover (2) away from the motor (1).

5. The high-torque electric power steering apparatus for a commercial vehicle of claim 4, characterized in that: The power transmission mechanism comprises a shaft coupling (25) connected with the power output shaft of the motor (1), the shaft coupling (25) is located in the shaft coupling accommodating cavity (21), the shaft coupling (25) is fixedly connected with the Z7 gear shaft (23), two Z6 gears (26) are respectively installed on the two support shafts (24), the Z7 gear shaft (23) is engaged with the two Z6 gears (26), and the Z6 gears (26) are further engaged with the Z4 planetary gear carrier (32).

6. The high-torque electric power steering apparatus for a commercial vehicle of claim 5, characterized in that: The input torque is transmitted to the coupling (25) through the motor (1), the coupling (25) is transmitted to the Z7 gear shaft (23), the Z6 gear (26) is transmitted to the Z4 planetary carrier (32), and then the Z2 planetary gear (35) and the Z2' planetary gear (31) are transmitted to the sun gear output shaft (34), and the sun gear output shaft (34) outputs torque.

7. The high-torque electric power steering apparatus for a commercial vehicle of claim 1, wherein: The worm gear mechanism comprises a worm (45) connected with a steering shaft (48), and a sector worm gear (46) is engaged on the worm (45), and a worm sleeve of the sector worm gear (46) is in interference fit with the sun gear output shaft (34).

8. The high-torque electric power steering apparatus for a commercial vehicle of claim 7, characterized in that: The diverter housing (4) comprises a worm gear accommodating cavity (41) and a worm accommodating cavity (42), one end of the worm gear accommodating cavity (41) is open, a through hole is formed at the other end of the worm gear accommodating cavity (41) for the sun gear output shaft (34) to pass out, one end of the worm accommodating cavity (42) is sealed by a compression plug (43), the other end of the worm accommodating cavity (42) is sealed by a steering shaft cover (44), and both ends of the worm (45) are respectively installed in the worm accommodating cavity (42) through bearings.

9. The high-torque electric power steering apparatus for a commercial vehicle of claim 7, wherein: A torsion bar (47) is installed in the steering shaft (48).

10. The high-torque electric power steering apparatus for a commercial vehicle of claim 8, wherein: An installation flange is arranged at the open end of the worm gear accommodating cavity (41) and is used in cooperation with the reducer housing (3).

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