Dual-mode electric power steering gear driven by belt

Abstract

The invention provides a dual-mode electric power steering gear driven by a belt, which comprises a steering gear shell assembly, an input shaft and screw nut assembly, a side cover rocker arm shaft assembly, an adjusting support assembly, an upper cover assembly, a sensor support plate, a corner torque sensor, a belt transmission assembly, a planetary reducer assembly and a motor assembly, a motor assembly serves as a power source, power is transmitted to an input shaft and screw assembly through a planetary reducer assembly and a belt transmission assembly in sequence, the input shaft and screw nut assembly outputs torque and angular displacement through a sector shaft, assistance torque is output through an input shaft, and two control modes of angular position and torque assistance are achieved. The scheme has the beneficial effects that according to the description of the scheme, the structure is simple, the design is reasonable, turbine and worm structures in a heavy circulating ball type dual-mode electric power steering gear are replaced by the planetary reducer, the belt gear and the like, the size is smaller, and the efficiency is improved.

Description

Technical Field

[0001] The invention relates to the fields of electromechanical systems and motor vehicle applications, and in particular to a dual-mode electric power steering device using belt drive. Background Art

[0002] In the automotive industry, with the continuous growth of the number of fuel vehicles, vehicle emissions are increasingly polluting the environment. At the same time, oil, as a non-renewable energy source, is also facing the crisis of depletion. Therefore, low-emission or zero-emission electric large-tonnage commercial vehicles have become the core development direction of today's wheeled vehicle technology due to their advantages of energy saving and environmental protection. Electric power steering technology (EPS) has been widely used in the field of domestic vehicles at home and abroad due to its significant advantages such as high integration, energy saving and high efficiency, but it is mostly used for family cars or passenger cars with steering loads ≤2t, while large-tonnage electric power steering technology suitable for electric buses, heavy trucks, special vehicles, etc. is still in a blank state, with urgent market demand and broad prospects.

[0003] In response to military needs, military wheeled vehicles have heavy single-axle loads, complex road conditions (such as trenches, off-road mountain roads, icy and snowy roads, and muddy roads), and harsh operating conditions. The chassis must not only meet the requirements of high mobility during road marches and operations, but also have good driving stability and off-road safety under extremely harsh road conditions. Among them, the steering system of wheeled vehicles is an important subsystem of the automobile chassis system, and its performance directly affects the vehicle's handling stability, driving comfort and driving safety. At present, the steering system of my country's military wheeled vehicles basically adopts a hydraulic power steering system, and the actuator is a recirculating ball hydraulic power steering gear. Therefore, the vehicle's steering return mainly depends on the steering positioning parameters, such as the kingpin castor angle and the kingpin inclination angle. When the positioning parameter error is large, the vehicle's return ability will become poor and unstable, thereby affecting the vehicle's maneuverability; for example, when the vehicle is driving at high speed, there will be a feeling of "floating" in the steering, that is, the steering assist is too large, which is determined by the principle of the recirculating ball hydraulic power steering gear. The steering pump in the hydraulic power steering system is powered by the engine. At high speed, the engine speed increases, the pressure of the hydraulic power steering system increases, and the steering assist naturally increases. Although the current new steering oil pump can achieve a decrease in oil pump flow pressure relief during high-speed steering, it cannot fundamentally solve the problem of "floating".

[0004] In order to improve the performance of the steering system and meet the driver's requirements for low-speed steering lightness, high-speed steering road feel and fuel economy, the automobile steering system has gone through four development stages: mechanical steering system (MS), hydraulic power steering system (HPS), electronically controlled hydraulic power steering system (EHPS) and electric power steering system (EPS).

[0005] The HPS system uses an engine-driven steering oil pump to provide hydraulic power, and achieves power steering through a steering control valve, solving the problem of excessive driver burden when the mechanical steering system is turning in situ and at low speeds. However, because its power assist effect is only related to the driver's operating force, the power assist characteristics are the same at different vehicle speeds, which can easily lead to "floating" steering when driving at high speeds. It is difficult for the driver to grasp the road feedback information and the steering road feel is poor.

[0006] The EHPS system adds an electronic control system to the HPS system. The electronic control unit adjusts the power assist of the hydraulic power assist system through the added solenoid valve according to the vehicle speed signal, thereby achieving a power assist effect in which the power assist torque changes with the vehicle speed. The EHPS also meets the driver's requirements for the lightness of the car's steering at low speeds and a good road feel at high speeds. However, due to the addition of electronic control units, vehicle speed sensors, solenoid valves, fluid distribution valves and other devices, the structure is more complex and the cost is higher. It is also unable to overcome the inherent defects of the traditional HPS, such as complex process, power assist characteristics affected by engine speed, energy consumption when not steering, easy leakage of hydraulic oil, high requirements for sealing, and frequent maintenance.

[0007] As people's requirements for automobile performance continue to increase, people hope that steering is light at low speeds and that they have good road feel at high speeds. None of the above systems can take into account the requirements of light steering at low speeds and road feel at high speeds at the same time. In order to solve the above contradictions in the steering system, the electric power steering system was born in the late 20th century. The electric power steering system is a new type of power steering device that uses an electric motor as a power source. It has developed rapidly in recent years and is gradually replacing traditional hydraulic and electro-hydraulic power steering gears. The electric power steering system is generally composed of a mechanical steering gear, a torque sensor, a vehicle speed sensor, an EPS controller, a reducer and a motor. Its working principle is as follows: the EPS controller obtains the steering torque, steering wheel angle and vehicle speed signal applied by the driver to the steering wheel by collecting the measurement values ​​of each sensor; according to the EPS control strategy, the target power torque is calculated and converted into the current command of the motor to control the motor to generate the corresponding power torque; the power torque is amplified by the reduction mechanism and acts on the mechanical steering gear to assist the driver in overcoming the steering resistance torque and realize the steering of the vehicle. EPS uses a motor to provide steering torque, which is adjusted in real time by the EPS controller, so that the car has different steering feelings at different speeds. At low speeds, the motor provides a larger torque, making the steering wheel easier to operate, thereby reducing the driver's steering burden; at high speeds, the motor provides a smaller torque, making the steering wheel more stable, thereby improving the steering road feel and improving the safety of the car when driving at high speeds. Therefore, EPS has become a research hotspot in the field of automotive power steering.

[0008] At present, electric power steering technology has been maturely applied in the field of small passenger cars, and in terms of structural form, most of them are rack and pinion steering devices or steering column steering devices. As for large-tonnage and heavy-duty vehicles, the applicant has previously applied for related technologies. For example, CN106379404A discloses a heavy-duty recirculating ball dual-mode electric power steering gear. The electric power steering device comprises: a housing assembly, an input shaft and screw assembly, a gear fan shaft assembly, a support seat assembly, a turbine, a worm, an inner end cover assembly, an angle torque sensor, an outer end cover assembly, a plum blossom connection sleeve assembly, and a motor assembly. A cavity with one end closed and the other end open is arranged in a horizontal direction inside the housing assembly. The input shaft and screw assembly is installed in the cavity of the housing assembly. One end of the input shaft and screw assembly is installed at the closed end. The other end of the input shaft and screw assembly extends out of the cavity of the housing assembly. The gear fan shaft assembly is installed in the housing assembly in a direction perpendicular to the input shaft and screw assembly so that the gear fan shaft assembly and the input shaft and screw assembly are connected through The gears are meshed; the support seat assembly is sleeved on the outside of the input shaft and the screw assembly and is used to limit the input shaft and the screw assembly; the worm is installed in the housing assembly along a direction perpendicular to the input shaft and the screw assembly, and one end of the worm is coaxially installed with the plum blossom connection sleeve assembly and the motor assembly in sequence; the turbine is meshed with the worm, and the worm drives the input shaft and the screw assembly to rotate; the inner end cover assembly is sleeved on the input shaft and the screw assembly and installed on the outside of the turbine, the angular torque sensor is axially connected to the input shaft and the screw assembly, the outer end cover assembly is sleeved on the input shaft and the screw assembly and installed on the outside of the angular torque sensor, and is fixed to the front end of the housing assembly.

[0009] However, the above-mentioned heavy-duty recirculating ball dual-mode electric power steering still has the following problems: 1. Difficulty in spatial arrangement. Since the steering device of heavy-duty vehicles is generally arranged in the vehicle power compartment, the space is tight. The current heavy-duty recirculating ball dual-mode electric power steering device occupies a large longitudinal space and is difficult to match the system.

[0010] 2. High requirements for processing precision. The heavy-duty recirculating ball dual-mode electric power steering uses a worm gear transmission, which requires high processing precision. The efficiency at the worm gear is 85%, and the total efficiency is 72%, which is low.

[0011] 3. Key components are difficult to repair. The input shaft of the heavy-duty recirculating ball dual-mode electric power steering gear is an integrated structure with the screw assembly, gear fan shaft assembly, turbine, and worm. It is difficult to test and repair and cannot be disassembled modularly.

[0012] 4. Low load bearing. The gear fan shaft assembly adopts assembled nuts, which bear a low load. If the steering nut and the guide tube pressure plate are not assembled tightly, a gap may occur, resulting in low transmission efficiency, low bearing capacity of the steel ball movement, and limited impact resistance.

[0013] In view of the above problems, the present invention provides a new steering device to solve various problems faced by the steering of heavy vehicles. Summary of the invention

[0014] The present invention aims at the deficiencies in the prior art and provides a dual-mode electric power steering device using belt drive which has a simple structure and reasonable design, not only saving layout space, but also improving transmission efficiency, enhancing load-bearing capacity, reducing parts processing requirements and facilitating parts maintenance, assembly and replacement.

[0015] In order to achieve the above object, the present invention provides a dual-mode electric power steering gear using belt drive, comprising a steering gear housing assembly, wherein an input shaft and a screw nut assembly and a side cover rocker arm shaft assembly are connected inside the steering gear housing assembly, and the input shaft and the screw nut assembly are drivingly connected to the side cover rocker arm shaft assembly; The input shaft and the screw nut assembly are movably connected with an adjustment support assembly, and the adjustment support assembly is arranged inside the steering gear housing assembly and is used for axially limiting the input shaft and the screw assembly; A motor assembly is disposed outside the steering gear housing assembly, the motor assembly is drivingly connected to a planetary reducer assembly, the planetary reducer assembly is drivingly connected to a belt drive assembly, and the belt drive assembly is drivingly connected to the input shaft and the screw nut assembly; The motor assembly, the planetary reducer assembly, and the input shaft and the screw nut assembly are located at the same end of the belt transmission assembly, and the axis lines of the motor assembly, the planetary reducer assembly, the input shaft and the screw nut assembly are parallel; The belt drive assembly comprises a small pulley and a large pulley, and the small pulley and the large pulley are connected with a belt; The small pulley is a hollow cylinder, which is transmission-connected to the planetary reducer assembly; The large pulley is connected to the input shaft and the screw nut assembly, and the input shaft and the screw nut assembly are spline-connected to the large pulley; The belt transmission assembly also includes a wheelbase support plate, the wheelbase support plate is provided with a large flange hole and an oblong hole, the planetary reducer assembly is connected to the wheelbase support plate, and the output end of the planetary reducer assembly passes through the large flange hole to connect to the small pulley; The wheelbase support plate is connected with a pad, and the pad is installed between the wheelbase support plate and the steering gear housing to constrain the coaxial position of the two; The wheelbase support plate is connected to an adjustment block, which contacts the side of the pad and is used to fine-tune the relative position of the wheelbase support plate and the pad perpendicular to the axial direction of the large pulley; A large pulley sealing plate is arranged on the outer side of the large pulley, and the large pulley sealing plate is coaxial with the steering screw rod and is used to prevent the belt from falling off; A small pulley sealing plate is arranged outside the small pulley, and the small pulley sealing plate is coaxial with the planetary reducer assembly and is used to prevent the belt from falling off; The steering screw is provided with a limiting sleeve, the end of which is in close contact with the large pulley, so as to prevent the large pulley from sliding toward the other end of the steering screw; The wheelbase support plate is connected with a belt drive assembly housing.

[0016] Further, the steering gear housing assembly includes a steering gear housing, wherein a first through-type cavity and a second through-type cavity perpendicular to each other are arranged inside the steering gear housing, and the distance between the axis lines of the first through-type cavity and the second through-type cavity at the closest point is a set value; Specifically, the first through-type cavity is provided with a first end face A perpendicular to the first through-type cavity at one end of the steering gear housing, and starting from the first end face A as a reference surface, a first inner circular surface B, a second inner circular surface C, a third inner circular surface D, a fourth inner circular surface E, a fifth inner circular surface F, a portion of the transmission cavity G located in the first through-type cavity, a sixth inner circular surface H, a seventh inner circular surface I, an eighth inner circular surface J, a ninth inner circular surface K, a first internal threaded surface L and a second end face M parallel to the first end face A, which constitute the coaxial center of the first through-type cavity, are processed in sequence; Specifically, the second through-type cavity is that the steering gear housing is provided with a third end surface N perpendicular to the first end surface A and parallel to the axis of the first through-type cavity, and starting from the third end surface N, a tenth inner circular surface O constituting the coaxial center of the second through-type cavity, a portion of the transmission cavity G located in the second through-type cavity, an eleventh inner circular surface P, a twelfth inner circular surface Q, a thirteenth inner circular surface R and a fourth end surface S parallel to the third end surface N are processed in sequence; The tenth inner circular surface O includes two arcs with different inner diameters but are concentric, and the radius of the arc of the tenth inner circular surface O close to the first through-type cavity is larger than the radius of the other arc; The steering gear housing is also processed with a fourteenth inner circular surface T, a fifteenth inner circular surface U, and a sixteenth inner circular surface V.

[0017] Further, the fifteenth inner circular surface U is installed with a rectangular sealing ring, and the sixteenth inner circular surface V is installed with an oil plug with a vent cap, and the oil plug with a vent cap is used for discharging and sealing the lubricating oil in the transmission cavity G; The second inner circular surface C is provided with a first oil seal; The thirteenth inner circular surface R is provided with a second oil seal, and the second oil seal is flush with the fourth end surface S; The fourteenth inner cylindrical surface T is provided with an oil hole screw plug for injecting lubricating oil into the transmission cavity G and sealing.

[0018] Further, the input shaft and the screw nut assembly penetrate the first through-type cavity and are coaxial with the first through-type cavity; The input shaft and screw nut assembly includes an input shaft, the input shaft box has an axial cavity, one end of the input shaft is provided with an external spline and a torsion bar made of elastic material is connected to the end through a pin, and a steering screw is connected through the cavity; The torsion bar is embedded in the end of the steering screw and is fixedly connected to the steering screw, and a needle bearing is arranged between the steering screw and the torsion bar; The steering screw is sleeved with a steering nut, the steering screw is provided with an external thread for a steel ball to pass through, and the steering nut is provided with an internal thread for a steel ball to pass through; The two ends of the steering nut are provided with depressions; One side of the steering nut is provided with teeth, and the other side is provided with a through hole passing through both ends in the depression, and the through hole is used for the steel ball to pass through; A ball return device is connected to the depression of the steering nut, and the ball return device is provided with a groove for the steel ball to pass through, one end of the groove is connected to the through hole, and the other end of the groove is connected to the internal thread end of the steering nut; The fifth inner surface F is provided with an angular contact ball bearing, and the angular contact ball bearing is connected to the steering screw.

[0019] Furthermore, the outer diameter of the steering screw is provided with a first thread groove SA for the steel ball to pass through; The steering nut is provided with a second thread groove SB for the steel ball to pass through, and the first thread groove SA and the second thread groove SB together constitute a passage for the steel ball; The two ends of the steering nut are respectively provided with a first groove SC-1 and a second groove SC-2, and the bottoms of the first groove SC-1 and the second groove SC-2 are respectively provided with connecting bolt holes SE-1 and SE-2; A bead return hole SD is provided between the first groove SC-1 and the second groove SC-2; The first groove SC-1 and the second groove SC-2 are embedded and connected with the bead return device, and the bead return device is provided with a bead guide groove SF, one end of the bead guide groove SF is connected to the first groove SC-1 or the second groove SC-2, and the other end of the bead guide groove SF is connected to the bead return hole SD; The bead returner is in the shape of a long strip as a whole, one end of which is connected to the first groove SC-1 or the second groove SC-2, and the other end of which is provided with an arc-shaped protrusion on the side, and the arc-shaped protrusion is provided with a countersunk bolt hole groove SG.

[0020] Further, the side cover rocker arm shaft assembly passes through the second through-type cavity and is coaxial with the second through-type cavity; The side cover rocker shaft assembly comprises a rocker shaft, the rocker shaft is processed with a sector gear structure with involute bevel teeth, and one end of the rocker shaft is provided with an annular groove; The outer side of one end of the rocker shaft where the annular groove is arranged is connected with a needle bearing, the outer side of the needle bearing is connected with a side cover, there is a certain interval between the side cover and the rocker shaft, the side cover is connected with an adjustment screw, and the adjustment screw passes through the side cover and is inserted into the annular groove of the rocker shaft; The adjusting screw is connected with an adjusting nut outside the side cover; The inner end of the adjusting screw is sleeved with an arm shaft screw plug, and there is a certain distance between the arm shaft screw plug and the adjusting screw; The side cover is respectively fitted and clamped with the third end surface N and the tenth inner circular surface O from outside to inside along the axial direction of the second through-type cavity, and a sealing ring is provided between the side cover and the tenth inner circular surface O; The eleventh inner cylindrical surface P is installed with a needle bearing, and the needle bearing is connected to the rocker arm shaft.

[0021] Further, the adjustment support assembly includes an adjustment support, the adjustment support includes two outer cylindrical surfaces of different diameters, and the outer cylindrical surface with a larger diameter is connected to the steering gear housing, and a sealing ring is provided between the outer cylindrical surface with a smaller diameter of the adjustment support and the steering gear housing; The two ends of the inner diameter of the adjustment support are respectively connected with a skeleton oil seal and a bearing, and the inner diameter of the adjustment support is provided with four inner circular surfaces of different diameters for installing and positioning the skeleton oil seal and the bearing; The bearing is connected to the steering screw, and the skeleton oil seal is movably connected to the steering screw.

[0022] Further, the steering gear housing is connected to an upper cover assembly, the upper cover assembly includes an upper cover, the upper cover is connected to the second end surface M, and the central opening of the upper cover is used for the input shaft to pass through; A skeleton oil seal and a deep groove ball bearing are arranged between the upper cover and the input shaft.

[0023] Further, the first internal thread surface L is threadedly connected with a sensor support plate, the sensor support plate is provided with a slot, the slot is connected with an angle torque sensor, and the angle torque sensor is connected around the input shaft and the steering screw; The two magnetic rings of the rotation angle torque sensor are respectively fixed with glue to the steering screw and the input shaft; The rotation angle torque sensor signal is connected to a control system, and the control system signal is connected to a motor assembly.

[0024] During operation, when the input shaft is rotated forward or backward through the steering wheel, since the input shaft and the steering screw are connected by an elastic torsion bar and there is a certain angle, preferably an angular displacement idle stroke of ± degrees, the steering screw and the input shaft can rotate coaxially with the input shaft only when the angular displacement idle stroke limit is reached. The angular torque sensor is connected to the input shaft and the steering screw. The control system calculates the target torque of the motor assembly by collecting the output torque value of the angular torque sensor, and drives the motor assembly to output the power assist torque in the torque control mode. The motor assembly performs a first-stage deceleration and torque increase through the planetary reducer assembly, and then performs a second-stage deceleration and torque increase through the belt drive assembly, and transmits the torque to the steering screw and drives the steering screw to rotate. At this time, the steel ball inside the input shaft and the screw nut assembly will follow the lead of the steering screw and roll on the inner thread of the steering nut. The steering nut guides the rolling steel ball to the groove of the ball return device at one end through the opening at one end of the inner thread. The steel ball enters the through hole of the steering nut through the groove of the ball return device. The steel ball then flows back along the through hole of the steering nut into the groove of the ball return device at the other end of the steering nut, and then enters the opening at the other end of the inner thread of the steering nut through the groove of the ball return device at the other end, and enters between the steering nut and the steering screw through the opening at the other end of the inner thread of the steering nut. The circulating rolling steel ball provides thrust to the steering nut, pushing the steering nut to make linear motion along the axial direction of the steering screw. Since the teeth of the steering nut are meshed with the rocker arm shaft assembly of the side cover, the rocker arm shaft converts the thrust and linear motion stroke of the steering nut into torque and angular displacement output.

[0025] When the input shaft stops rotating through the steering wheel, the elastic torsion bar between the input shaft and the steering screw overcomes the angular displacement between the input shaft and the steering screw during rotation and generates elastic deformation. When there is no external force on the input shaft, the relative position with the steering screw will be restored.

[0026] The beneficial effects of this scheme can be known from the description of the above scheme. The structure is simple and the design is reasonable. The advantages are as follows: 1. Save layout space. When the worm gear structure was originally used, the power assist device and the steering housing assembly crossed and stretched in two planes. This solution cancels the worm gear structure and uses a planetary reducer and belt drive instead, which can make the power assist device and the steering housing assembly parallel and close, making the structure more compact, saving space in the vehicle, and facilitating the space layout of the entire vehicle.

[0027] 2. Improve transmission efficiency. The transmission efficiency of the turbine and worm structure is about 85%. If the mature products of planetary reducer and belt gear are used instead, the transmission efficiency will be 95%.

[0028] 3. Reduced machining accuracy requirements. With belt drive, there is no accuracy requirement for the distance between the power assist device axis and the steering screw axis, thus reducing the machining accuracy requirements for parts.

[0029] 4. Modular design facilitates component maintenance, assembly and replacement. The electric steering device is divided into several modules, including the motor, planetary reducer assembly, belt drive assembly, input shaft and screw nut assembly, and side cover rocker shaft assembly. The modules are connected by matching, and a single module can be disassembled separately, which greatly facilitates maintenance, assembly and replacement.

[0030] 5. Enhanced load-bearing capacity. The new design of the steering nut uses an integrated nut instead of an assembled nut. The nut has enhanced load-bearing capacity, making the steel ball move more smoothly and insensitive to ground impact loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a top view of a partial cross-section of the present invention; Figure 2 It is a partial cross-sectional view of the present invention from the left side; Figure 3 It is a right side view of the present invention; Figure 4 It is a bottom sectional view of the steering gear housing of the present invention; Figure 5 It is a left side cross-sectional view of the steering gear housing of the present invention; Figure 6 It is a right side cross-sectional view of the belt drive assembly of the present invention; Figure 7 It is a top view cross-sectional view of the belt drive assembly; Figure 8 It is a top view cross-sectional view of the planetary reducer assembly; Fig. 9 It is a rear cross-sectional view of the upper cover assembly; Fig.10 It is a partial cross-sectional view of the input shaft and the screw nut assembly from the front view; Fig.11 It is a partial cross-sectional view of the left side view of the side cover rocker arm shaft assembly; Fig.12 It is a schematic diagram of the steering nut structure; Fig.13 yes Figure 1 A-A view; Fig.14 It is a schematic diagram of the structure of the bead return device; Fig.15 yes Fig.14 A front view of Fig.16 yes Fig.15 Left view of; In the figure, 1, steering gear housing assembly; 2, input shaft and screw nut assembly; 3, side cover rocker arm shaft assembly; 4, adjustment support assembly; 5, upper cover assembly; 6, sensor support plate; 7, angular torque sensor; 8, motor assembly; 9, belt drive assembly; 10, planetary reducer assembly; 11, steering gear housing; 12, rectangular sealing ring; 13, oil plug with vent cap; 14, first oil seal; 15, second oil seal; 16, angular contact ball bearing; 17, needle bearing; 18, oil hole screw plug; 19, input shaft; 20, steering screw; 21, steering nut; 22, bead return device; 23, torsion bar; 24, pin shaft; 25, needle bearing; 26, rocker arm shaft; 27, side cover; 28, adjustment screw; 29, adjustment nut; 30, arm shaft screw plug; 31, needle bearing; 32, sealing ring ; 33, adjustment support; 34, skeleton oil seal; 35, bearing; 36, sealing ring; 37, upper cover; 38, skeleton oil seal; 39, deep groove ball bearing; 40, belt cover; 41, pad; 42, belt housing; 43, small pulley sealing plate; 44, spacer; 45, large pulley sealing plate; 46, adjustment block; 47, small pulley; 48, large pulley; 49, belt; 50, upper sealing plate; 51 , small pulley shaft; 52, upper planetary carrier; 53, lower sealing plate; 54, planetary gear; 55, sealing plate; 56, inner ring gear; 57, sun gear shaft; 58, planetary gear housing; 59, oil-free bushing; 60-1, deep groove ball bearing; 60-2, deep groove ball bearing; 60-3, deep groove ball bearing; 60-4, deep groove ball bearing; 61-1, sealing ring; 61-2, sealing ring; 62, limit sleeve. DETAILED DESCRIPTION

[0032] In order to clearly illustrate the technical features of this solution, this solution is described below through a specific implementation method.

[0033] like Figure 1-16 As shown, this embodiment is a dual-mode electric power steering gear using a belt drive, comprising a steering gear housing assembly 1, the steering gear housing assembly 1 is internally connected with an input shaft and a screw nut assembly 2 and a side cover rocker arm shaft assembly 3, and the input shaft and the screw nut assembly 2 are drivingly connected to the side cover rocker arm shaft assembly 3; The input shaft and the screw nut assembly 2 are movably connected with an adjustment support assembly 4, which is arranged inside the steering gear housing assembly 1 and is used for axially limiting the input shaft and the screw assembly 2; A motor assembly 8 is disposed outside the steering gear housing assembly 1, the motor assembly 8 is drivingly connected to a planetary reducer assembly 10, the planetary reducer assembly 10 is drivingly connected to a belt drive assembly 9, and the belt drive assembly 9 is drivingly connected to the input shaft and the screw nut assembly 2; The motor assembly 8, the planetary reducer assembly 10 and the input shaft and the screw nut assembly 2 are located at the same end of the belt transmission assembly 9, and the motor assembly 8, the planetary reducer assembly 10 and the axis lines of the input shaft and the screw nut assembly 2 are parallel; Preferably, the steering gear housing assembly 1 includes a steering gear housing 11, wherein a first through cavity and a second through cavity perpendicular to each other are arranged inside the steering gear housing 11, and the distance between the axis lines of the first through cavity and the second through cavity at the closest point is a set value; Specifically, the first through-type cavity is provided with a first end face A perpendicular to the first through-type cavity at one end of the steering gear housing 11, and the first end face A is used as a reference surface to sequentially process the first inner cylindrical surface B, the second inner cylindrical surface C, the third inner cylindrical surface D, the fourth inner cylindrical surface E, the fifth inner cylindrical surface F, the part of the transmission cavity G located in the first through-type cavity, the sixth inner cylindrical surface H, the seventh inner cylindrical surface I, the eighth inner cylindrical surface J, the ninth inner cylindrical surface K, the first internal threaded surface L and the second end face M parallel to the first end face A, which constitute the coaxial center of the first through-type cavity; The second through-type cavity is specifically that the steering gear housing 11 is provided with a third end surface N perpendicular to the first end surface A and parallel to the axis of the first through-type cavity, and starting from the third end surface N, a tenth inner circular surface O constituting the coaxial center of the second through-type cavity, a portion of the transmission cavity G located in the second through-type cavity, an eleventh inner circular surface P, a twelfth inner circular surface Q, a thirteenth inner circular surface R and a fourth end surface S parallel to the third end surface N are processed in sequence; The tenth inner circular surface O includes two arcs with different inner diameters but are concentric, and the radius of the arc of the tenth inner circular surface O close to the first through cavity is larger than the radius of the other arc; The steering gear housing 11 is further processed to have a fourteenth inner circumferential surface T, a fifteenth inner circumferential surface U, and a sixteenth inner circumferential surface V.

[0034] Preferably, the fifteenth inner circular surface U is provided with a rectangular sealing ring 12, and the sixteenth inner circular surface V is provided with an oil plug 13 with a vent cap, and the oil plug 13 with a vent cap is used for discharging and sealing the lubricating oil in the transmission cavity G; The second inner circular surface C is provided with a first oil seal 14; The thirteenth inner circular surface R is provided with a second oil seal 15, and the second oil seal 15 is flush with the fourth end surface S; The fourteenth inner cylindrical surface T is provided with an oil hole screw plug 18 for injecting lubricating oil into the transmission cavity G and sealing.

[0035] Preferably, the input shaft and the screw-nut assembly 2 pass through the first through-type cavity and are coaxial with the first through-type cavity; The input shaft and screw nut assembly 2 includes an input shaft 19, the input shaft 19 box has an axial cavity, one end of the input shaft 19 is provided with an external spline and a torsion bar 23 made of elastic material is connected to the end through a pin 24, and a steering screw 20 is connected through the cavity; The torsion bar 23 is embedded in the end of the steering screw 20 and is fixedly connected to the steering screw 20. A needle bearing 25 is provided between the steering screw 20 and the torsion bar 23. The steering screw 20 is sleeved with a steering nut 21, the steering screw 20 is provided with an external thread for a steel ball to pass through, and the steering nut 21 is provided with an internal thread for a steel ball to pass through; Both ends of the steering nut 21 are provided with depressions; One side of the steering nut 21 is provided with teeth, and the other side is provided with a through hole through both ends in the recess, and the through hole is used for the steel ball to pass through; A ball return device 22 is connected to the depression of the steering nut 21 . The ball return device 22 is provided with a groove for the steel ball to pass through. One end of the groove is connected to the through hole, and the other end of the groove is connected to the internal thread end of the steering nut 21 .

[0036] An angular contact ball bearing 16 is installed on the fifth inner circular surface F, and the angular contact ball bearing 16 is connected to the steering screw 20 .

[0037] Preferably, the outer diameter of the steering screw 20 is provided with a first thread groove SA for the steel ball to pass through; The steering nut 21 is provided with a second thread groove SB for the steel ball to pass through, and the first thread groove SA and the second thread groove SB together constitute a passage for the steel ball; The first groove SC-1 and the second groove SC-2 are respectively provided at both ends of the steering nut 21, and the bottoms of the first groove SC-1 and the second groove SC-2 are respectively provided with connecting bolt holes SE-1 and SE-2; A bead return hole SD is provided between the first groove SC-1 and the second groove SC-2; The first groove SC-1 and the second groove SC-2 are embedded and connected with a bead return device 22, and the bead return device is provided with a bead guide groove SF, one end of the bead guide groove SF is connected to the first groove SC-1 or the second groove SC-2, and the other end of the bead guide groove SF is connected to the bead return hole SD; The bead return device 22 is in the shape of a long strip as a whole. One end of the bead return device 22 is connected to the first groove SC-1 or the second groove SC-2. An arc-shaped protrusion is provided on the side of the other end of the bead return device 22, and a countersunk bolt hole groove SG is provided on the arc-shaped protrusion.

[0038] Preferably, the side cover rocker arm shaft assembly 3 passes through the second through cavity and is coaxial with the second through cavity; The side cover rocker shaft assembly 3 includes a rocker shaft 26, which is processed with a sector gear structure with involute bevel teeth, and one end of the rocker shaft 26 is provided with an annular groove; The outer side of one end of the annular groove of the rocker arm shaft 26 is connected with a needle bearing 31, and the outer side of the needle bearing 31 is connected with a side cover 27. There is a certain interval between the side cover 27 and the rocker arm shaft 26. The side cover 27 is connected with an adjustment screw 28, and the adjustment screw 28 passes through the side cover and is inserted into the annular groove of the rocker arm shaft 26. The adjusting screw 28 is connected to the outside of the side cover 27 with an adjusting nut 29; The inner end of the adjusting screw 28 is sleeved with an arm shaft screw plug 30 and there is a certain distance between the arm shaft screw plug 30 and the adjusting screw 28; The side cover 27 is respectively fitted and clamped with the third end surface N and the tenth inner circular surface O from outside to inside along the axial direction of the second through cavity, and a sealing ring 32 is provided between the side cover 27 and the tenth inner circular surface O; The eleventh inner cylindrical surface P is provided with a needle roller bearing 17 , and the needle roller bearing 17 is connected to the rocker arm shaft 26 .

[0039] Preferably, the adjustment support assembly 4 includes an adjustment support 33, the adjustment support 33 includes an outer cylindrical surface with two diameters, and the outer cylindrical surface with a larger diameter is connected to the steering gear housing 11, and a sealing ring 36 is provided between the outer cylindrical surface with a smaller diameter of the adjustment support 33 and the steering gear housing 11; The two ends of the inner diameter of the adjustment support 33 are respectively connected with a skeleton oil seal 34 and a bearing 35. The inner diameter of the adjustment support 33 is provided with four inner circular surfaces of different diameters for installing and positioning the skeleton oil seal 34 and the bearing 35. The bearing 35 is connected to the steering screw 20 , and the skeleton oil seal 34 is movably connected to the steering screw 20 .

[0040] Preferably, the steering gear housing 11 is connected to an upper cover assembly 5, the upper cover assembly 5 includes an upper cover 37, the upper cover 37 is connected to the second end surface M, and the central opening of the upper cover 37 is used for the input shaft 19 to pass through; A skeleton oil seal 38 and a deep groove ball bearing 39 are provided between the upper cover 37 and the input shaft 19 .

[0041] Preferably, the belt drive assembly 9 includes a small pulley 47 and a large pulley 48, and the small pulley 47 and the large pulley 48 are connected with a belt 49; The small pulley 47 is a hollow cylinder, which is transmission-connected to the planetary reducer assembly 9; The large pulley 48 connects the input shaft and the screw-nut assembly 2, and the input shaft and the screw-nut assembly 2 are spline-connected with the large pulley 48; The belt drive assembly 9 also includes a wheelbase support plate 40, which is provided with a large flange hole and an oblong hole, the planetary reducer assembly 10 is connected to the wheelbase support plate 40, and the output end of the planetary reducer assembly 10 passes through the large flange hole to connect to the small pulley 47; The wheelbase support plate 40 is connected with a backing plate 41, and the backing plate 41 is installed between the wheelbase support plate 40 and the steering gear housing 11 to constrain the coaxial position of the two; The wheelbase support plate 40 is connected with an adjustment block 46, which contacts the side of the pad 41 and is used to fine-tune the relative position of the wheelbase support plate 40 and the pad 41 perpendicular to the axial direction of the large pulley 48; A large pulley sealing plate 45 is disposed outside the large pulley 48, and the large pulley sealing plate 45 is coaxial with the steering screw 20 to prevent the belt 49 from falling off; A small pulley sealing plate 43 is provided on the outside of the small pulley 47, and the small pulley sealing plate 43 is coaxial with the planetary reducer assembly 9 to prevent the belt 49 from falling off; The steering screw 20 is provided with a limiting sleeve 44, the end of which is in close contact with the large pulley 48, so as to prevent the large pulley 48 from sliding toward the other end of the steering screw 20; The wheelbase support plate 40 is connected to a belt drive assembly housing 42 .

[0042] Preferably, the planetary reducer assembly 10 includes a planetary gear housing 58 , and the planetary gear housing 58 is provided with an inner gear ring 56 ; The inner gear ring 56 is meshed with a planetary gear 54, and the planetary gear 54 is meshed with a sun gear shaft 57, and the sun gear shaft 57 is located at the axis of the planetary gear housing 58; The two sides of the planetary gear 54 are rotatably connected to the upper planetary carrier 52 and the small pulley shaft 51, and the center of the upper planetary carrier 52 and the small pulley shaft 51 is rotatably connected to the sun gear shaft 57; A spacer 62 is provided between the upper planet carrier 52 and the small pulley shaft 51 to support the axial distance between the upper planet carrier 52 and the small pulley shaft 51; One end of the sun gear shaft 57 is provided with an internal spline for transmission connection with the output shaft of the motor assembly 8, and the other end of the sun gear shaft 57 is rotationally connected to the small pulley shaft 51; The sun gear shaft 57 is provided with teeth and meshes with the planetary gears 54 through the teeth. The small pulley shaft 51 includes a lower planet carrier end, which is rotatably connected to the planetary gear 54. A circular groove is provided at the center of the lower planet carrier end and is rotatably connected to the sun gear shaft 57 through the circular groove. The other end of the small pulley shaft 51 is connected to the belt drive assembly 9; An upper sealing plate 50 is connected to one end of the planetary gear housing 58 close to the motor assembly 8, and a deep groove ball bearing 60-1 and a sealing ring 61-1 are connected between the upper sealing plate 50 and the sun gear shaft 57; The end of the planetary gear housing 58 away from the motor assembly 8 is connected to a lower sealing plate 53, and a sealing plate 55 is provided on the side of the lower sealing plate 53 away from the planetary gear housing 58. A deep groove ball bearing 60-4 is connected between the lower sealing plate 53 and the small pulley shaft 51, and a sealing ring 61-2 is connected between the sealing plate 55 and the small pulley shaft 51; A deep groove ball bearing 60 - 3 is connected between the upper planet carrier 52 and the sun gear shaft 57 ; A deep groove ball bearing 60 - 2 is connected between the small pulley shaft 51 and the sun gear shaft 57 ; Oil-free bushings 59 are provided between the upper planet carrier 52 and the planetary gear 54 , and between the small pulley shaft 51 and the planetary gear 54 .

[0043] Preferably, the first internal thread surface L is threadedly connected with a sensor support plate 6, the sensor support plate 6 is provided with a slot, the slot is connected with an angle torque sensor 7, and the angle torque sensor 7 surrounds and connects the input shaft 19 and the steering screw 20; The two magnetic rings of the angular torque sensor 7 are respectively glued and fixed to the steering screw 20 and the input shaft 19; The signal of the rotation angle torque sensor 7 is connected to the control system, and the signal of the control system is connected to the motor assembly 8.

[0044] During operation, when the input shaft 19 is rotated forward or backward through the steering wheel, since the input shaft 19 is connected to the steering screw 20 through the elastic torsion bar 23 and there is a certain angle, preferably an angular displacement idle stroke of ±10 degrees, the steering screw 20 and the input shaft 19 can rotate coaxially with the input shaft 19 only when the angular displacement idle stroke limit is reached. The angular torque sensor 7 is connected to the input shaft 19 and the steering screw 20. The control system calculates the target torque of the motor assembly 8 by collecting the output torque value of the angular torque sensor 7, and drives the motor assembly 8 to output the power assist torque in the torque control mode. The motor assembly 8 performs a first-stage deceleration and torque increase through the planetary reducer assembly 9, and then performs a second-stage deceleration and torque increase through the belt drive assembly 8, and transmits the torque to the steering screw 20 and drives the steering screw 20 to rotate. At this time, the steel ball in the input shaft and the screw nut assembly 2 will follow the screw lead of the steering screw 20 and roll on the inner thread of the steering nut 21. The steering nut 21 guides the rolling steel ball to the groove of the bead return device 22 at one end through the opening at one end of the inner thread. The steel ball enters the through hole of the steering nut 21 through the groove of the bead return device 22. The steel ball then flows back along the through hole of the steering nut 21 into the groove of the bead return device 22 at the other end of the steering nut 21, and then enters the opening at the other end of the inner thread of the steering nut 21 through the groove of the bead return device 22 at the other end, and enters between the steering nut 21 and the steering screw 20 through the opening at the other end of the inner thread of the steering nut 21. The circularly rolling steel ball provides thrust to the steering nut 21, pushing the steering nut 21 to make linear motion along the axial direction of the steering screw 20. Since the teeth of the steering nut 21 are meshed with the side cover rocker arm shaft assembly 3, the rocker arm shaft 26 converts the thrust and linear motion stroke of the steering nut 21 into torque and angular displacement output.

[0045] When the input shaft 19 stops being rotated by the steering wheel, the elastic torsion bar 23 between the input shaft 19 and the steering screw 20 overcomes the angular displacement stroke between the input shaft 19 and the steering screw 20 during the rotation process and generates elastic deformation. In the absence of external force on the input shaft 19, the relative position with the steering screw 20 will be restored.

[0046] Technical features not described in the present invention can be achieved through or by adopting existing technologies and will not be described in detail herein. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A dual-mode electric power steering using a belt drive, It is characterized in that The steering gear housing assembly (1) comprises an input shaft and a screw nut assembly (2) and a side cover rocker arm shaft assembly (3) connected internally to the steering gear housing assembly (1); the input shaft and a screw nut assembly (2) is drivingly connected to the side cover rocker arm shaft assembly (3); The input shaft and the screw nut assembly (2) are movably connected with an adjustment support assembly (4), and the adjustment support assembly (4) is arranged inside the steering gear housing assembly (1) and is used for axially limiting the input shaft and the screw assembly (2); The steering gear housing assembly (1) is provided with a motor assembly (8) outside, the motor assembly (8) is drivingly connected to a planetary reducer assembly (10), the planetary reducer assembly (10) is drivingly connected to a belt drive assembly (9), and the belt drive assembly (9) is drivingly connected to the input shaft and the screw nut assembly (2); The motor assembly (8), the planetary reducer assembly (10) and the input shaft and screw nut assembly (2) are located at the same end of the belt transmission assembly (9), and the axis lines of the motor assembly (8), the planetary reducer assembly (10) and the input shaft and screw nut assembly (2) are parallel; The belt drive assembly (9) comprises a small pulley (47) and a large pulley (48), and the small pulley (47) and the large pulley (48) are connected with a belt (49); The small pulley (47) is a hollow cylinder, and is transmission-connected to the planetary reducer assembly (9); The large pulley (48) is connected to the input shaft and the screw nut assembly (2), and the input shaft and the screw nut assembly (2) are spline-connected to the large pulley (48); The belt drive assembly (9) further comprises a wheelbase support plate (40), wherein the wheelbase support plate (40) is provided with a large flange hole and an oblong hole, the planetary reducer assembly (10) is connected to the wheelbase support plate (40), and the output end of the planetary reducer assembly (10) passes through the large flange hole to connect to the small pulley (47); The wheelbase support plate (40) is connected to a pad (41), and the pad (41) is installed between the wheelbase support plate (40) and the steering gear housing (11) to constrain the coaxial position of the two. The wheelbase support plate (40) is connected to an adjustment block (46), the adjustment block (46) contacts the side surface of the pad (41) and is used to fine-tune the relative position of the wheelbase support plate (40) and the pad (41) perpendicular to the axial direction of the large pulley (48); A large pulley sealing plate (45) is arranged outside the large pulley (48), and the large pulley sealing plate (45) is coaxial with the steering screw (20) and is used to prevent the belt (49) from falling off; A small pulley sealing plate (43) is arranged outside the small pulley (47), and the small pulley sealing plate (43) is coaxial with the planetary reducer assembly (9) and is used to prevent the belt (49) from falling off; The steering screw (20) is provided with a limiting sleeve (44), the end of the limiting sleeve (44) being in close contact with the large pulley (48) to prevent the large pulley (48) from sliding toward the other end of the steering screw (20); The wheelbase support plate (40) is connected to a belt drive assembly housing (42).

2. A dual-mode electric power steering device using belt drive according to claim 1, It is characterized in that The steering gear housing assembly (1) comprises a steering gear housing (11), wherein a first through-type cavity and a second through-type cavity which are perpendicular to each other are arranged inside the steering gear housing (11), and the distance between the axis centers of the first through-type cavity and the second through-type cavity at the closest point is a set value; Specifically, the first through-type cavity is provided with a first end face (A) perpendicular to the first through-type cavity at one end of the steering gear housing (11), and starting from the first end face (A) as a reference surface, a first inner circular surface (B), a second inner circular surface (C), a third inner circular surface (D), a fourth inner circular surface (E), a fifth inner circular surface (F), a portion of the transmission cavity (G) located in the first through-type cavity, a sixth inner circular surface (H), a seventh inner circular surface (I), an eighth inner circular surface (J), a ninth inner circular surface (K), a first internal threaded surface (L) and a second end face (M) parallel to the first end face (A) are sequentially processed to form a coaxial first through-type cavity; The second through-type cavity is specifically, the steering gear housing (11) is provided with a third end surface (N) perpendicular to the first end surface (A) and parallel to the axis of the first through-type cavity, and starting from the third end surface (N), a tenth inner circular surface (O) constituting the coaxial center of the second through-type cavity, a portion of the transmission cavity (G) located in the second through-type cavity, an eleventh inner circular surface (P), a twelfth inner circular surface (Q), a thirteenth inner circular surface (R) and a fourth end surface (S) parallel to the third end surface (N) are processed in sequence; The tenth inner circular surface (O) includes two arcs with different inner diameters but are concentric, and the radius of the arc of the tenth inner circular surface (O) close to the first through-type cavity is larger than the radius of the other arc; The steering gear housing (11) is also processed with a fourteenth inner circular surface (T), a fifteenth inner circular surface (U), and a sixteenth inner circular surface (V).

3. A dual-mode electric power steering device using belt drive according to claim 2, It is characterized in that The fifteenth inner circular surface (U) is provided with a rectangular sealing ring (12), and the sixteenth inner circular surface (V) is provided with an oil plug with a vent cap (13), and the oil plug with a vent cap (13) is used for discharging and sealing the lubricating oil in the transmission cavity (G); The second inner circular surface (C) is provided with a first oil seal (14); The thirteenth inner circular surface (R) is provided with a second oil seal (15), and the second oil seal (15) is flush with the fourth end surface (S); The fourteenth inner cylindrical surface (T) is provided with an oil hole screw plug (18) for injecting lubricating oil into the transmission cavity (G) and for sealing.

4. A dual-mode electric power steering device using belt drive according to claim 2, It is characterized in that The input shaft and screw nut assembly (2) penetrates the first through-type cavity and is coaxial with the first through-type cavity; The input shaft and screw nut assembly (2) comprises an input shaft (19), the input shaft (19) box having an axial cavity, one end of the input shaft (19) being provided with an external spline and the end being connected to a torsion bar (23) made of an elastic material via a pin (24), the cavity being connected to a steering screw (20); The torsion bar (23) is embedded in the end of the steering screw (20) and is fixedly connected to the steering screw (20), and a needle bearing (25) is provided between the steering screw (20) and the torsion bar (23); The steering screw (20) is sleeved with a steering nut (21); the steering screw (20) is provided with an external thread for a steel ball to pass through, and the steering nut (21) is provided with an internal thread for a steel ball to pass through; Both ends of the steering nut (21) are provided with recesses; The steering nut (21) is provided with teeth on one side, and a through hole penetrating both ends is provided in the depression on the other side, the through hole being used for a steel ball to pass through; A bead return device (22) is connected to the depression of the steering nut (21), and the bead return device (22) is provided with a groove for the steel ball to pass through, one end of the groove is connected to the through hole, and the other end of the groove is connected to the internal thread end of the steering nut (21); An angular contact ball bearing (16) is mounted on the fifth inner circular surface (F), and the angular contact ball bearing (16) is connected to the steering screw (20).

5. A dual-mode electric power steering device using belt drive according to claim 4, It is characterized in that The outer diameter of the steering screw (20) is provided with a first thread groove SA for the steel ball to pass through; The steering nut (21) is provided with a second thread groove SB for a steel ball to pass through, and the first thread groove SA and the second thread groove SB together constitute a passage for the steel ball; The steering nut (21) is provided with a first groove SC-1 and a second groove SC-2 at both ends thereof, and connecting bolt holes SE-1 and SE-2 are provided at the bottoms of the first groove SC-1 and the second groove SC-2, respectively; A bead return hole SD is provided between the first groove SC-1 and the second groove SC-2; The first groove SC-1 and the second groove SC-2 are embedded and connected with the bead return device (22), and the bead return device is provided with a bead guide groove SF, one end of the bead guide groove SF is connected to the first groove SC-1 or the second groove SC-2, and the other end of the bead guide groove SF is connected to the bead return hole SD; The bead return device (22) is in the shape of a long strip as a whole, one end of the bead return device (22) is connected to the first groove SC-1 or the second groove SC-2, and the other end of the bead return device (22) is provided with an arc-shaped protrusion on the side surface, and the arc-shaped protrusion is provided with a countersunk bolt hole groove SG.

6. A dual-mode electric power steering device using belt drive according to claim 2, It is characterized in that The side cover rocker arm shaft assembly (3) passes through the second through-type cavity and is coaxial with the second through-type cavity; The side cover rocker shaft assembly (3) comprises a rocker shaft (26), the rocker shaft (26) being processed with a sector gear structure having involute bevel teeth, and one end of the rocker shaft (26) being provided with an annular groove; The outer side of one end of the rocker arm shaft (26) provided with the annular groove is connected to a needle bearing (31), the outer side of the needle bearing (31) is connected to a side cover (27), a certain interval is provided between the side cover (27) and the rocker arm shaft (26), the side cover (27) is connected to an adjustment screw (28), and the adjustment screw (28) passes through the side cover and is inserted into the annular groove of the rocker arm shaft (26); The adjusting screw (28) is connected to an adjusting nut (29) outside the side cover (27); An arm shaft screw plug (30) is sleeved on the inner end of the adjusting screw (28), and a certain distance exists between the arm shaft screw plug (30) and the adjusting screw (28); The side cover (27) is respectively fitted and clamped with the third end surface (N) and the tenth inner circular surface (O) from the outside to the inside along the axial direction of the second through-type cavity, and a sealing ring (32) is provided between the side cover (27) and the tenth inner circular surface (O); The eleventh inner cylindrical surface (P) is mounted with a needle roller bearing (17), and the needle roller bearing (17) is connected to the rocker arm shaft (26).

7. A dual-mode electric power steering device using belt drive according to claim 4, It is characterized in that The adjustment support assembly (4) comprises an adjustment support (33), the adjustment support (33) comprising two outer cylindrical surfaces of different diameters, the outer cylindrical surface of the larger diameter being connected to the steering gear housing (11), and a sealing ring (36) being provided between the outer cylindrical surface of the smaller diameter of the adjustment support (33) and the steering gear housing (11); The two ends of the inner diameter of the adjustment support (33) are respectively connected to a skeleton oil seal (34) and a bearing (35); the inner diameter of the adjustment support (33) is provided with four inner circular surfaces of different diameters for mounting and positioning the skeleton oil seal (34) and the bearing (35); The bearing (35) is connected to the steering screw (20), and the skeleton oil seal (34) is movably connected to the steering screw (20).

8. A dual-mode electric power steering device using belt drive according to claim 4, It is characterized in that The steering gear housing (11) is connected to an upper cover assembly (5), the upper cover assembly (5) comprising an upper cover (37), the upper cover (37) being connected to the second end surface (M), and the central opening of the upper cover (37) being used for the input shaft (19) to pass through; A skeleton oil seal (38) and a deep groove ball bearing (39) are provided between the upper cover (37) and the input shaft (19).

9. A dual-mode electric power steering device using belt drive according to claim 2, It is characterized in that The first internal thread surface (L) is threadedly connected to a sensor support plate (6), the sensor support plate (6) is provided with a slot, the slot is connected to a rotation angle torque sensor (7), and the rotation angle torque sensor (7) is connected around the input shaft (19) and the steering screw (20); The two magnetic rings of the rotation angle torque sensor (7) are respectively fixed to the steering screw (20) and the input shaft (19) by adhesive; The rotation angle torque sensor (7) is signal-connected to a control system, and the control system is signal-connected to a motor assembly (8).

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