Electric power steering device of automobile

Abstract

The invention discloses an automobile electric power steering device which is characterized in that a first transmission wheel is coaxially connected with the output end of a motor, a first synchronous belt is wound on the peripheral walls of the first transmission wheel and a first belt wheel, the first belt wheel is coaxially connected with a second transmission wheel, and a second synchronous belt is wound on the peripheral walls of the second transmission wheel and a second belt wheel; the second belt wheel is coaxially connected with the steering screw rod, the speed reduction shell is provided with a first strip-shaped groove and an eccentric adjusting assembly, the first transmission wheel is movably matched with the first strip-shaped groove through a first screw, and the eccentric adjusting assembly movably abuts against the second synchronous belt. A first screw can drive a first transmission wheel to move along a first strip-shaped groove, then the tensioning force of a first synchronous belt is adjusted, by rotating an eccentric adjusting assembly, the different diameters of the eccentric adjusting assembly abut against a second synchronous belt, and the tensioning force of the second synchronous belt is adjusted; therefore, the tension degree of the first synchronous belt and the second synchronous belt is adjusted.

Description

Technical Field

[0001] The present invention relates to the technical field of steering gears, in particular to an electric power steering device for an automobile. Background Art

[0002] With the increasing demand for energy conservation and environmental protection in automobiles, electric power steering (EPS) systems are gaining widespread adoption. Based on the motor's location, electric power steering systems can be categorized into three main types: column-assisted steering (C-EPS), pinion-assisted steering (P-EPS), and rack-assisted steering (R-EPS). As electric steering becomes increasingly common, the power assistance provided by C-EPS and P-EPS is limited, limiting their use to small and medium-sized vehicles. To meet the needs of mid-to-large vehicles, R-EPS is required.

[0003] The R-EPS's motor and rack are arranged parallel to each other, meeting the chassis layout requirements of different vehicle models. The motor's power assist is applied directly to the rack via a ball screw structure, resulting in a short reaction time and direct power assist. The power assist effect is both fast and accurate, enhancing the driver's control of the steering system. The ball screw also has a higher load capacity, enabling the use of a higher-power motor to provide greater power assist torque, meeting the needs of larger vehicles. Currently, most R-EPS systems are belt-type, connecting the motor and ball screw via a belt. Due to the high output power of the motor used, the belt tension must be strictly controlled. If the belt is too loose, it will jump teeth. If it is too tight, it will wear quickly, affecting its service life. Therefore, belt installation and tension adjustment are crucial. Summary of the Invention

[0004] In response to the technical problem that the belt tensioning force needs to be strictly controlled, the present invention proposes an automobile electric power steering device, in which a first screw can drive a first transmission wheel to move along a first strip groove, thereby adjusting the tensioning force of the first synchronous belt. By rotating the eccentric adjustment component, the different diameters of the eccentric adjustment component are abutted against the second synchronous belt, and the tensioning force of the second synchronous belt is adjusted, thereby achieving adjustment of the tension of the first synchronous belt and the second synchronous belt.

[0005] The technical solution adopted by the present invention is as follows: An electric power steering device for an automobile includes a motor, a first transmission wheel, a second transmission wheel, a first pulley, a second pulley, a first synchronous belt, a second synchronous belt, a reduction housing and a steering screw, wherein: the first transmission wheel is coaxially connected to the output end of the motor, the first synchronous belt is wound around the first transmission wheel and the outer peripheral wall of the first pulley, the first pulley is coaxially connected to the second transmission wheel, the second synchronous belt is wound around the second transmission wheel and the outer peripheral wall of the second pulley, the second pulley is coaxially connected to the steering screw, the first transmission wheel, the second transmission wheel, the first pulley and the second pulley are respectively arranged inside the reduction housing; the reduction housing is provided with a first strip groove and an eccentric adjustment assembly, the first transmission wheel is movably engaged with the first strip groove through a first screw, and the eccentric adjustment assembly is movably abutted against the second synchronous belt.

[0006] Optionally, the reduction housing is provided with the first strip groove on one side, and a plurality of first protrusions are provided on the other side of the reduction housing. The motor is provided with a plurality of second protrusions along the circumferential direction, and the first protrusions and the second protrusions are arranged in a one-to-one correspondence. The first protrusion is provided with a second strip groove, or the second protrusion is provided with a second strip groove, and the second strip groove is for the second screw to pass through.

[0007] Optionally, a through hole is provided on a side of the reduction housing away from the first strip-shaped groove, and the first protrusion is arranged along the circumference of the through hole.

[0008] Optionally, the first screw includes a limiting portion, a threaded portion and a smooth portion connected in sequence, the outer peripheral wall of the threaded portion is sleeved with a first nut, the limiting portion and the first nut are respectively arranged on both sides of the first strip groove, a first bearing is provided at one end of the inner peripheral wall of the first transmission wheel, and an internal spline is provided at the other end of the inner peripheral wall of the first transmission wheel, the smooth portion is tightly fitted with the inner ring of the first bearing, the output end of the motor is provided with an external spline that cooperates with the internal spline, and the smooth portion and the output end of the motor do not contact each other.

[0009] Optionally, the eccentric adjustment assembly includes a third screw, a cam, a second bearing and a roller. The third screw is eccentrically fixed to the cam, and the free end of the third screw passes through the cam and the reduction housing in sequence and is matched with a second nut. The inner ring of the second bearing is tightly fitted with the outer peripheral wall of the cam, and the outer ring of the second bearing is tightly fitted with the inner peripheral wall of the roller, and the roller rolls against the second synchronous belt.

[0010] Optionally, the reduction housing includes a first reduction housing and a second reduction housing, the first reduction housing is provided with a first cavity for accommodating a first transmission wheel, a first pulley and a first synchronous belt, the second reduction housing is provided with a second cavity for accommodating a second transmission wheel, a second pulley, an eccentric adjustment assembly and a second synchronous belt, the first strip groove and the eccentric adjustment assembly are arranged on the same side of the first reduction housing, and the motor is arranged on the other side of the first reduction housing.

[0011] Optionally, it also includes a steering housing, a steering nut is provided on the outer peripheral wall of the steering screw, the steering screw and the steering nut are both arranged inside the steering housing, the reduction housing is connected to the steering housing, the steering housing is provided with an oil inlet pipe, the oil inlet pipe is connected to a sealing assembly, the sealing assembly includes an end cover and a connecting pipe with a hollow hole, one end of the connecting pipe is provided with a first boss that is gap-matched with the end cover, and the other end of the connecting pipe is provided with a second boss that is tightly connected to the oil inlet pipe, and a breathable and waterproof membrane is provided inside the first boss.

[0012] Optionally, a plurality of water flow grooves are provided at intervals along the circumferential direction at the free end of the first boss, and the breathable and waterproof membrane is flush with the lowest point of the water flow grooves.

[0013] Optionally, a plurality of elastic ridges are provided at intervals on the inner peripheral wall of the end cover, the elastic ridges correspond to the water flow grooves in an staggered manner, the elastic ridges are interference fit with the outer peripheral wall of the first boss, the outer peripheral wall of the first boss is provided with an annular groove, and the elastic ridges and the annular groove are arranged perpendicular to each other.

[0014] Optionally, the connecting pipe is provided with a cover plate, the bottom surface of the cover plate is provided with an elastic ring bulge that abuts against the free end of the oil inlet pipe, the free end of the oil inlet pipe is provided with a limiting groove that cooperates with the cover plate, the outer peripheral wall of the second boss is provided with an external thread, and the oil inlet pipe is provided with an internal thread that cooperates with the external thread.

[0015] The beneficial effects of the present invention are as follows: (1) When in use, the motor drives the first pulley to rotate synchronously through the first transmission wheel and the first synchronous belt, and the first pulley drives the second pulley to rotate synchronously through the second transmission wheel and the second synchronous belt, so that the second pulley drives the steering screw to rotate. The two-stage pulley transmission formed by the first transmission wheel and the first pulley, and the second transmission wheel and the second pulley has a larger transmission speed ratio and higher transmission efficiency. The first screw can drive the first transmission wheel to move along the first strip groove, thereby adjusting the tension of the first synchronous belt. By rotating the eccentric adjustment component, the different diameters of the eccentric adjustment component are abutted against the second synchronous belt, and the tension of the second synchronous belt is adjusted, thereby adjusting the tension of the first synchronous belt and the second synchronous belt.

[0016] (2) During assembly, first move the first transmission wheel along the first strip groove to adjust the tightness of the first synchronous belt. When it is adjusted to the appropriate position, tighten the first nut through the through hole so that the limiting part of the first screw and the first nut clamp the two sides of the first strip groove. Then, the output end of the motor is coaxially assembled with the first transmission wheel through the cooperation of the external spline and the internal spline. When the tension of the second synchronous belt needs to be adjusted, rotate the eccentric adjustment component as a whole so that the large diameter or small diameter of the eccentric adjustment component abuts against the second synchronous belt, thereby adjusting the tension of the second synchronous belt. After adjustment, tighten the second nut through the through hole. The third screw is provided with a clamping protrusion. The clamping protrusion and the second nut are respectively located on both sides of the reduction housing. Tightening the second nut can install the eccentric adjustment component on the reduction housing.

[0017] (3) The oil inlet pipe is used to add lubricating oil to the interior of the electric power steering device of the automobile. In the prior art, the oil inlet pipe is generally sealed with screws. When the heat from the outside or the motor and controller causes the air pressure inside the steering device to increase, the oil seal, steering housing or reduction housing of the steering device are very likely to leak oil due to the high pressure. The provision of a breathable waterproof membrane allows the electric power steering device of the automobile to maintain internal and external pressure balance, while preventing moisture from entering the interior of the electric power steering device of the automobile. The end cover is interference-fitted with the outer peripheral wall of the first boss through the elastic ribs on the inner peripheral wall of the end cover and the outer peripheral wall of the first boss. Water and gas flow out through the gap between the inner peripheral wall of the end cover and the outer peripheral wall of the first boss. The provision of an annular groove increases the pulling force of the end cover, making it difficult to pull out. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of an electric power steering device for an automobile proposed in an embodiment of the present invention;

[0019] Figure 2 A transmission diagram of an electric power steering device for an automobile proposed in an embodiment of the present invention;

[0020] Figure 3 A schematic diagram of a second strip groove of an electric power steering device for an automobile according to an embodiment of the present invention;

[0021] Figure 4 A schematic diagram of an eccentric adjustment assembly of a pulley speed reduction steering device according to an embodiment of the present invention;

[0022] Figure 5 A schematic diagram of the oil inlet pipeline of the pulley speed reduction steering device proposed in an embodiment of the present invention;

[0023] Figure 6 A schematic diagram of a capping assembly with a pulley deceleration and steering device according to an embodiment of the present invention;

[0024] Figure 7 Schematic diagram of the waterproof and breathable membrane of the cover assembly proposed in an embodiment of the present invention.

[0025] The symbols in the drawings are: 1, motor; 2, first transmission wheel; 3, second transmission wheel; 4, first pulley; 5, second pulley; 6, first synchronous belt; 7, second synchronous belt; 8, reduction housing; 9, steering screw; 10, first strip groove; 11, eccentric adjustment assembly; 12, first screw; 13, first protrusion; 14, second protrusion; 15, second strip groove; 16, second screw; 17, through hole; 18, limit portion; 19, threaded portion; 20, first nut; 2 1. Third screw; 22. Cam; 23. Second bearing; 24. Roller; 25. First reduction housing; 26. Second reduction housing; 27. Steering housing; 28. Steering nut; 29. ​​Oil inlet pipe; 30. Sealing cover assembly; 31. Hollow hole; 32. Connecting pipe; 33. End cover; 34. First boss; 35. Second boss; 36. Breathable waterproof membrane; 37. Water flow groove; 38. Elastic convex strip; 39. Ring groove; 40. Cover plate; 41. Elastic ring convex; 42. External thread. DETAILED DESCRIPTION

[0026] The present application will be further described in detail below with reference to the accompanying drawings and examples.

[0027] like Figure 1 and 2As shown, this embodiment discloses an electric power steering device for an automobile, comprising a motor 1, a first transmission wheel 2, a second transmission wheel 3, a first pulley 4, a second pulley 5, a first synchronous belt 6, a second synchronous belt 7, a reduction housing 8 and a steering screw 9, wherein: the first transmission wheel 2 is coaxially connected to the output end of the motor 1, the first synchronous belt 6 is wound around the outer peripheral wall of the first transmission wheel 2 and the first pulley 4, the first pulley 4 is coaxially connected to the second transmission wheel 3, the second synchronous belt 7 is wound around the outer peripheral wall of the second transmission wheel 3 and the second pulley 5, the second pulley 5 is coaxially connected to the steering screw 9, the first transmission wheel 2, the second transmission wheel 3, the first pulley 4, and the second pulley 5 are respectively arranged inside the reduction housing 8; the reduction housing 8 is provided with a first strip groove 10 and an eccentric adjustment component 11, the first transmission wheel 2 is movably engaged with the first strip groove 10 by a first screw 12, and the eccentric adjustment component 11 is movably abutted against the second synchronous belt 7. During operation, the motor 1 drives the first pulley 4 to rotate synchronously via the first transmission wheel 2 and the first synchronous belt 6. The first pulley 4 then drives the second pulley 5 to rotate synchronously via the second transmission wheel 3 and the second synchronous belt 7, causing the second pulley 5 to rotate the steering screw 9. The two-stage pulley transmission formed by the first transmission wheel 2 and the first pulley 4, and the second transmission wheel 3 and the second pulley 5, has a larger transmission ratio and higher transmission efficiency. The first screw 12 drives the first transmission wheel 2 to move along the first strip groove 10, thereby adjusting the tension of the first synchronous belt 6. By rotating the eccentric adjustment component 11, the different diameters of the eccentric adjustment component 11 abut against the second synchronous belt 7, adjusting the tension of the second synchronous belt 7, thereby adjusting the tension of the first synchronous belt 6 and the second synchronous belt 7.

[0028] In this embodiment, if Figure 3As shown, the reduction housing 8 has a first strip groove 10 on one side and a plurality of first protrusions 13 on the other side. The motor 1 has a plurality of second protrusions 14 along its circumference, with the first protrusions 13 and the second protrusions 14 arranged in a one-to-one correspondence. The first protrusions 13 are provided with a second strip groove 15, or the second protrusions 14 are provided with a second strip groove 15, which is provided for the passage of a second screw 16. When the tension of the first synchronous belt 6 needs to be adjusted, the second screw 16 is removed, the motor 1 is separated from the reduction housing 8, and the first screw 12 is loosened. A through hole 17 is provided on the side of the reduction housing 8 facing away from the first strip groove 10, and the first protrusions 13 are arranged along the circumference of the through hole 17. The first screw 12 includes a stopper 18, a threaded portion 19, and a smooth portion connected in sequence. The outer peripheral wall of the threaded portion 19 is provided with a first nut 20. The stopper 18 and the first nut 20 are respectively provided on either side of the first strip groove 10. A first bearing is provided at one end of the inner peripheral wall of the first transmission wheel 2, and an internal spline is provided at the other end of the inner peripheral wall of the first transmission wheel 2. The smooth portion is tightly engaged with the inner ring of the first bearing. The output end of the motor 1 is provided with an external spline that engages with the internal spline, and the smooth portion does not contact the output end of the motor 1. During assembly, the first transmission wheel 2 is first moved along the first strip groove 10 to adjust the tension of the first synchronous belt 6. When the adjustment is to the appropriate position, the first nut 20 is tightened through the through hole 17 so that the stopper 18 and the first nut 20 of the first screw 12 clamp the two sides of the first strip groove 10. Then, the output end of the motor 1 is coaxially assembled with the first transmission wheel 2 through the engagement of the external spline and the internal spline. The design of the second slot 15 ensures that the motor output remains coaxial with the first transmission pulley 2. A second screw passes through the first or second protrusion and engages with a nut, securing the motor. The second transmission pulley and the first pulley are coaxially connected by a transmission rod, which is rotatably connected to the reduction housing 8 via a bearing, providing support for the transmission rod.

[0029] like Figure 4As shown, the eccentric adjustment assembly 11 includes a third screw 21, a cam 22, a second bearing 23 and a roller 24. The third screw 21 is eccentrically fixed to the cam 22, and the free end of the third screw 21 passes through the cam 22 and the reduction housing 8 in sequence and is matched with a second nut. The inner ring of the second bearing 23 is tightly fitted with the outer peripheral wall of the cam 22, and the outer ring of the second bearing 23 is tightly fitted with the inner peripheral wall of the roller 24. The roller 24 rolls against the second synchronous belt 7. The third screw 21, the cam 22, the second bearing 23 and the roller 24 form an eccentric adjustment assembly 11. When it is necessary to adjust the tension of the second synchronous belt 7, the third screw is rotated, and then the eccentric adjustment assembly 11 is rotated as a whole, so that the large diameter or small diameter of the eccentric adjustment assembly 11 is against the second synchronous belt 7, and then the tension of the second synchronous belt 7 is adjusted. After adjustment, the second nut is tightened through the through hole 17. The third screw 21 is provided with a clamping protrusion, and the clamping protrusion and the second nut are respectively located on both sides of the reduction housing 8. Tightening the second nut can install the eccentric adjustment assembly 11 on the reduction assembly.

[0030] like Figure 1 As shown, the reduction housing 8 includes a first reduction housing 25 and a second reduction housing 26. The first reduction housing 25 is provided with a first cavity for accommodating the first transmission wheel 2, the first pulley 4, and the first synchronous belt 6. The second reduction housing 26 is provided with a second cavity for accommodating the second transmission wheel 3, the second pulley 5, the eccentric adjustment assembly 11, and the second synchronous belt 7. The first strip groove 10 and the eccentric adjustment assembly 11 are provided on the same side of the first reduction housing 25, and the motor 1 is provided on the other side of the first reduction housing 25. A sealing plate may be provided on the side of the second reduction housing facing away from the first reduction housing to seal the second transmission wheel, the second pulley, the eccentric adjustment assembly, and the second synchronous belt in the second cavity.

[0031] like Figure 5 and 7As shown, it also includes a steering housing 27, a steering nut 28 is provided on the outer peripheral wall of the steering screw 9, the steering screw 9 and the steering nut 28 are both arranged inside the steering housing 27, the reduction housing 8 is connected to the steering housing 27, the steering housing 27 is provided with an oil inlet pipe 29, the oil inlet pipe 29 is connected to a cover assembly 30, the cover assembly 30 includes an end cover 33 and a connecting pipe 32 with a hollow hole 31, one end of the connecting pipe 32 is provided with a first boss 34 that is clearance-matched with the end cover 33, and the other end of the connecting pipe 32 is provided with a second boss 35 that is tightly connected to the oil inlet pipe 29, and a breathable and waterproof membrane 36 is provided inside the first boss 34. The oil inlet pipe 29 is used to add lubricating oil to the electric power steering system. In conventional technology, the oil inlet pipe 29 is typically sealed with screws. When the air pressure inside the electric power steering system rises, the oil seal, steering housing 27, or reduction housing 8 are susceptible to oil leakage due to the high pressure. The provision of the breathable waterproof membrane 36 maintains pressure balance between the inside and outside of the electric power steering system while preventing moisture from entering the system. The inner diameter of the hollow hole 31 of the connecting pipe 32 is 8-9 cm. If the diameter of the hollow hole 31 is less than 8 cm, lubricating oil can easily accumulate on the inner wall of the hollow hole 31, causing blockage and impairing air evacuation. If the hollow hole 31 is larger than 9 cm, the dimensions of the connecting pipe 32 and the breathable waterproof membrane 36 must be increased accordingly, increasing manufacturing costs. The free end of the first boss 34 is provided with a plurality of water flow grooves 37 spaced circumferentially. The breathable waterproof membrane 36 is flush with the lowest point of the water flow grooves 37. The water isolated by the breathable waterproof membrane 36 can flow out from the water flow channel 37 and out from the gap between the end cover 33 and the first boss 34 .

[0032] In this embodiment, if Figure 6As shown, the inner circumferential wall of the end cap 33 is provided with a plurality of elastic ridges 38 at intervals. These ridges 38 correspond to the water flow grooves 37 in a staggered manner and form an interference fit with the outer circumferential wall of the first boss 34. The outer circumferential wall of the first boss 34 is provided with an annular groove 39, and the elastic ridges and annular groove 39 are arranged perpendicular to each other. The elastic ridges 38 on the inner circumferential wall of the end cap 33 form an interference fit with the outer circumferential wall of the first boss 34, allowing water and gas to flow out through the gap between the inner circumferential wall of the end cap 33 and the outer circumferential wall of the first boss 34. The provision of the annular groove 39 increases the pull-out force of the end cap 33, making it difficult to pull out. The connecting pipe 32 is provided with a cover plate 40. The bottom surface of the cover plate 40 is provided with an elastic annular protrusion 41 that abuts against the free end of the oil inlet pipe 29. The free end of the oil inlet pipe 29 is provided with a retaining groove that cooperates with the cover plate 40. The outer peripheral wall of the second boss 35 is provided with an external thread 42, and the oil inlet pipe 29 is provided with an internal thread that cooperates with the external thread 42. When the first boss 34 and the oil inlet pipe 29 are tightly fitted together through the external thread 42 and the internal thread, the cover plate 40 seals the oil inlet pipe 29, and the elastic annular protrusion 41 further provides a sealing effect.

[0033] It is understood that the specific embodiments described above are only used to explain the relevant inventions, rather than to limit the inventions. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not have contradictions or conflicts. Any equivalent structural transformation made using the contents of the present invention specification and drawings, directly or indirectly applied to other related technical fields, are also included in the protection scope of the present invention.

Claims

1. An automotive electric power steering device, characterized in that: It includes a motor, a first transmission wheel, a second transmission wheel, a first pulley, a second pulley, a first synchronous belt, a second synchronous belt, a reduction housing and a steering screw, wherein: The first transmission wheel is coaxially connected to the output end of the motor, the first synchronous belt is wound around the first transmission wheel and the outer peripheral wall of the first pulley, the first pulley is coaxially connected to the second transmission wheel, the second synchronous belt is wound around the second transmission wheel and the outer peripheral wall of the second pulley, the second pulley is coaxially connected to the steering screw, and the first transmission wheel, the second transmission wheel, the first pulley, and the second pulley are respectively arranged inside the reduction housing; The reduction housing is provided with a first strip groove and an eccentric adjustment assembly. The first transmission wheel is movably matched with the first strip groove through a first screw, and the eccentric adjustment assembly is movably abutted against the second synchronous belt.

2. The automotive electric power steering device according to claim 1, characterized in that: The reduction housing is provided with the first strip groove on one side, and a plurality of first protrusions are provided on the other side. The motor is provided with a plurality of second protrusions along the circumferential direction. The first protrusions are arranged in a one-to-one correspondence with the second protrusions. The first protrusion is provided with a second strip groove, or the second protrusion is provided with a second strip groove, and the second strip groove is for the second screw to pass through.

3. The automotive electric power steering device according to claim 2, characterized in that: A through hole is provided on a side of the reduction housing away from the first strip groove, and the first protrusion is arranged along the circumference of the through hole.

4. The automotive electric power steering device according to claim 1, characterized in that: The first screw includes a limiting portion, a threaded portion and a smooth portion connected in sequence, the outer peripheral wall of the threaded portion is sleeved with a first nut, the limiting portion and the first nut are respectively arranged on both sides of the first strip groove, a first bearing is arranged at one end of the inner peripheral wall of the first transmission wheel, and an internal spline is arranged at the other end of the inner peripheral wall of the first transmission wheel, the smooth portion is tightly matched with the inner ring of the first bearing, the output end of the motor is provided with an external spline matched with the internal spline, and the smooth portion and the output end of the motor do not contact each other.

5. The automotive electric power steering device according to claim 1, characterized in that: The eccentric adjustment assembly includes a third screw, a cam, a second bearing and a roller. The third screw is eccentrically fixed on the cam, and the free end of the third screw passes through the cam and the reduction housing in sequence and is matched with a second nut. The inner ring of the second bearing is tightly matched with the outer peripheral wall of the cam, the outer ring of the second bearing is tightly matched with the inner peripheral wall of the roller, and the roller rolls against the second synchronous belt.

6. The automotive electric power steering device according to claim 2, characterized in that: The reduction housing includes a first reduction housing and a second reduction housing, the first reduction housing is provided with a first cavity for accommodating a first transmission wheel, a first pulley and a first synchronous belt, the second reduction housing is provided with a second cavity for accommodating a second transmission wheel, a second pulley, an eccentric adjustment assembly and a second synchronous belt, the first strip groove and the eccentric adjustment assembly are arranged on the same side of the first reduction housing, and the motor is arranged on the other side of the first reduction housing.

7. The automotive electric power steering device according to claim 1, characterized in that: It also includes a steering housing, a steering nut is provided on the outer peripheral wall of the steering screw, the steering screw and the steering nut are both arranged inside the steering housing, the reduction housing is connected to the steering housing, the steering housing is provided with an oil inlet pipeline, the oil inlet pipeline is connected with a sealing assembly, the sealing assembly includes an end cover and a connecting pipe with a hollow hole, one end of the connecting pipe is provided with a first boss which is gap-matched with the end cover, the other end of the connecting pipe is provided with a second boss which is tightly connected with the oil inlet pipeline, and a breathable and waterproof membrane is provided inside the first boss.

8. The automotive electric power steering device according to claim 7, characterized in that: The free end of the first boss is provided with a plurality of water flow grooves at intervals along the circumferential direction, and the breathable and waterproof membrane is flush with the lowest point of the water flow grooves.

9. The automotive electric power steering device according to claim 8, characterized in that: The inner wall of the end cover is provided with a plurality of elastic ridges at intervals, the elastic ridges correspond to the water flow grooves in an alternating manner, the elastic ridges are interference fit with the outer wall of the first boss, the outer wall of the first boss is provided with an annular groove, and the elastic ridges and the annular groove are arranged perpendicular to each other.

10. The automotive electric power steering device according to claim 7, characterized in that: The connecting pipe is provided with a cover plate, the bottom surface of the cover plate is provided with an elastic ring convex which abuts against the free end of the oil inlet pipe, the free end of the oil inlet pipe is provided with a limiting groove which cooperates with the cover plate, the outer peripheral wall of the second boss is provided with an external thread, and the oil inlet pipe is provided with an internal thread which cooperates with the external thread.

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