Electric power steering device and steering housing thereof

Abstract

The utility model discloses an electric power steering device and a steering shell thereof, the electric power steering device comprises a body, the inner circumferential wall of the body is provided with a cylindrical protrusion used for being in sliding fit with a steering nut, and one side of the cylindrical protrusion is provided with a through hole used for a rack on the steering nut to penetrate through. Notches are formed in the connecting positions of the two axial ends of the cylindrical protrusion and the through hole respectively, and the distance between the two notches is larger than the distance between the two opposite side walls of the through hole. The rack is movably located in the through hole, the two end faces of the steering nut are prevented from interfering with the cylindrical protrusion in the reciprocating motion through the arrangement of the notches, meanwhile, the effect of the overall weight of the shell is achieved, and cost is reduced and efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of steering gear, specifically relates to electric power steering device and its steering casing. BACKGROUND

[0002] With the popularization of automobile electric power steering system (EPS), the structure design of its core component - electric steering casing directly influences the reliability and durability of the steering system. The traditional electric steering casing needs to integrate and accommodate key components such as worm gear transmission system, steering screw rod and steering nut. The rack of the outer peripheral wall of the steering nut needs to pass through the hole of the casing and mesh with the fan teeth of the rocker shaft. However, there are the following contradictory design defects in the prior art: in order to ensure the meshing accuracy of the rack and the rocker shaft, the hole needs to maintain a very small gap with the rack, but during reciprocating motion, the steering nut is easy to produce frictional interference with the inner wall of the hole, resulting in abnormal vibration, noise and transmission efficiency loss. SUMMARY

[0003] In view of the technical problem that the steering nut is easy to produce frictional interference with the inner wall of the hole, the utility model provides an electric power steering device and its steering casing. The setting of the gap avoids the interference between the two end faces of the steering nut and the cylindrical protrusion during reciprocating movement, and also plays a role in the overall weight of the casing.

[0004] The technical scheme adopted by the utility model is as follows: a steering casing, comprising a body, a cylindrical protrusion is arranged on the inner peripheral wall of the body for sliding cooperation with a steering nut, a through hole is arranged on one side of the cylindrical protrusion for the rack on the steering nut to pass through, and a gap is arranged at the connection between the axial two ends of the cylindrical protrusion and the through hole. The distance between the two gaps is greater than the distance between the opposite two side walls of the through hole.

[0005] Optionally, the inner wall of the cylindrical protrusion is surrounded to form a first cavity for accommodating the steering nut, the casing is further provided with a second cavity for accommodating a worm gear, the first cavity and the second cavity are communicated, and the diameter of the second cavity is greater than that of the first cavity.

[0006] The utility model further discloses an electric power steering device, which comprises a steering nut and the above-mentioned steering casing, one side of the steering nut is in sliding abutment with the cylindrical protrusion, and the middle part of the other side of the steering nut is provided with a rack for meshing with a rocker shaft.

[0007] Optionally, one end of the steering nut is provided with a first protruding ring, the other end of the steering nut is provided with a second protruding ring, the rack is arranged between the first protruding ring and the second protruding ring, one side of the first protruding ring and one side of the second protruding ring are respectively in sliding abutment with the cylindrical protrusion, the other side of the first protruding ring is in movable cooperation with the gap at one end of the cylindrical protrusion, and the other side of the second protruding ring is in movable cooperation with the gap at the other end of the cylindrical protrusion.

[0008] Optionally, the diameter of the first convex ring is the same as the diameter of the second convex ring, and the free ends of the rack protrude from the outer wall surface of the first convex ring and the outer wall surface of the second convex ring.

[0009] Optionally, the root of the rack is provided with a reinforcing rib, and the reinforcing rib, the first convex ring and the second convex ring form a groove.

[0010] Optionally, the outer peripheral wall of the first convex ring and the outer peripheral wall of the second convex ring are respectively provided with an annular groove, and a wear-resistant ring is installed in the annular groove and protrudes from the annular groove.

[0011] Optionally, the inner peripheral wall of the steering nut is provided with a flat groove for installing a ball returning device and an inner raceway for rolling of the ball.

[0012] The beneficial effects of the utility model are that: the rack is movably located in the through hole, the setting of the notch avoids interference between the two end surfaces of the steering nut and the cylindrical protrusion during reciprocating movement, and also plays a role in reducing the overall weight of the shell, thereby reducing cost and increasing efficiency. The cavity wall of the first cavity, i.e. the cylindrical protrusion, and the steering nut slide against each other, and through the reaction force of the shell on the steering nut, the radial force of the rocker shaft on the steering nut is offset, thereby avoiding deformation of the steering screw passing through the steering nut; the free end of the rack, i.e. the end engaged with the rocker shaft, protrudes from the first convex ring and the second convex ring, which can not only increase the strength of the rack itself, but also increase the convenience of assembling the rack and the rocker shaft, thereby avoiding interference of the first convex ring and the second convex ring with the engagement of the rack and the rocker shaft during assembly. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The structure diagram of the steering shell is provided for the embodiment of the utility model.

[0014] Figure 2 The structure diagram of the steering nut is provided for the embodiment of the utility model.

[0015] The marks in the drawings are as follows: 1, body; 2, cylindrical protrusion; 3, through hole; 4, notch; 5, second cavity; 6, steering nut; 7, rack; 8, first convex ring; 9, second convex ring; 10, reinforcing rib; 11, groove; 12, annular groove; 13, flat groove; 14, inner raceway. DETAILED DESCRIPTION

[0016] The application will be further described in detail below in combination with the drawings and embodiments.

[0017] As Figure 1As shown in the embodiment, the steering shell comprises a body 1, an inner circumferential wall of the body 1 is provided with a cylindrical protrusion 2 for slidingly matching with a steering nut 6, one side of the cylindrical protrusion 2 is provided with a through hole 3 for allowing a rack 7 on the steering nut 6 to pass through, and the axial two ends of the cylindrical protrusion 2 are respectively provided with notches 4 at the connection positions with the through hole 3, and the distance between the two notches 4 is greater than the distance between the opposite two side walls of the through hole 3. The rack 7 is movably arranged in the through hole 3, and the notches 4 avoid the interference between the two end faces of the steering nut 6 and the cylindrical protrusion 2 during reciprocating movement, and also play the role of the overall weight of the shell, thereby reducing the cost and increasing the efficiency.

[0018] In the embodiment, as shown in the figure, Figure 1 the inner wall of the cylindrical protrusion 2 is surrounded to form a first cavity for accommodating the steering nut 6, the shell is further provided with a second cavity 5 for accommodating a worm wheel, the first cavity is communicated with the second cavity 5, and the diameter of the second cavity 5 is greater than that of the first cavity. The steering nut 6 and the cavity wall of the first cavity, i.e. the cylindrical protrusion 2, slide against each other, and through the reaction force of the shell on the steering nut 6, the radial force of the rocker shaft on the steering nut 6 is offset, thereby avoiding the deformation of the steering screw passing through the inside of the steering nut 6 due to stress.

[0019] As shown in the figure, Figure 2 the embodiment further discloses an electric power-assisted steering device, which comprises the steering nut 6 and the above-mentioned steering shell, one side of the steering nut 6 slideably abuts against the cylindrical protrusion 2, and the middle part of the other side of the steering nut 6 is provided with the rack 7 for engaging with the rocker shaft. One end of the steering nut 6 is provided with a first protruding ring 8, the other end of the steering nut 6 is provided with a second protruding ring 9, the rack 7 is arranged between the first protruding ring 8 and the second protruding ring 9, one side of the first protruding ring 8 and one side of the second protruding ring 9 respectively slideably abut against the cylindrical protrusion 2, the other side of the first protruding ring 8 movably cooperates with the notch 4 at one end of the cylindrical protrusion 2, and the other side of the second protruding ring 9 movably cooperates with the notch 4 at the other end of the cylindrical protrusion 2.

[0020] As shown in the figure, Figure 2 the diameter of the first protruding ring 8 is the same as that of the second protruding ring 9, and the free ends of the rack 7 protrude from the outer wall surfaces of the first protruding ring 8 and the second protruding ring 9. The free ends of the rack 7, i.e. the end engaging with the rocker shaft, protrude from the first protruding ring 8 and the second protruding ring 9, which can increase the strength of the rack 7 itself and increase the convenience of the engagement between the rack 7 and the rocker shaft during assembly, thereby avoiding the interference of the first protruding ring 8 and the second protruding ring 9 with the engagement between the rack 7 and the rocker shaft during assembly.

[0021] In the embodiment, as shown in the figure, Figure 2As shown, the root of the rack 7 is provided with a reinforcing rib 10, and the reinforcing rib 10, the first convex ring 8 and the second convex ring 9 form a groove 11. The reinforcing rib 10 increases the engagement strength of the rack 7, and the design of the groove 11 plays a role in reducing weight without affecting the engagement strength, thereby reducing the overall weight of the steering nut 6.

[0022] As shown in the drawings, the first convex ring 8 and the second convex ring 9 are arranged on the inner wall of the housing. Figure 2 As shown, the outer peripheral wall of the first convex ring 8 and the outer peripheral wall of the second convex ring 9 are respectively provided with an annular groove 12, and a wear-resistant ring is installed in the annular groove 12, and the wear-resistant ring protrudes from the annular groove 12. When the first convex ring 8 and the second convex ring 9 abut against the inner wall of the housing and reciprocate in the inner wall of the housing under the driving of the steering screw, the wear-resistant ring directly moves with the housing, thereby increasing the wear resistance of the steering nut 6. The material of the wear-resistant ring can be rubber.

[0023] In this embodiment, the inner wall of the steering nut 6 is provided with a flat groove 13 for installing a ball returning device and an inner raceway 14 for rolling of the ball, which is a prior art.

[0024] It can be understood that the above-described specific embodiments are only used to explain the related utility model, and are not limited to the utility model. In addition, it should be noted that, for the convenience of description, only the parts related to the utility model are shown in the drawings. The multiple technical solutions in the same embodiment and the multiple technical solutions of different embodiments can be arranged and combined to form new technical solutions without contradiction or conflict. Any equivalent structural transformation, direct or indirect application in other related technical fields, is also included in the protection scope of the utility model.

Claims

1. A steering housing characterized by, The body is provided with an inner circumferential wall with a cylindrical protrusion for sliding fit with a steering nut, one side of the cylindrical protrusion is provided with a through hole for the rack on the steering nut to pass through, and the axial ends of the cylindrical protrusion are respectively provided with notches at the connection with the through hole, the distance between the two notches is greater than the distance between the opposite side walls of the through hole.

2. The steering housing of claim 1, wherein, The inner wall of the cylindrical protrusion is surrounded to form a first cavity for accommodating the steering nut, the shell is further provided with a second cavity for accommodating a worm wheel, the first cavity and the second cavity are communicated, and the diameter of the second cavity is greater than the diameter of the first cavity.

3. An electric power steering apparatus characterized by comprising: The steering nut is slidingly abutted with the cylindrical protrusion on one side, and the rack for engaging with the rocker shaft is arranged in the middle of the other side of the steering nut.

4. The electric power assisted steering apparatus of claim 3, wherein One end of the steering nut is provided with a first protruding ring, the other end of the steering nut is provided with a second protruding ring, the rack is arranged between the first protruding ring and the second protruding ring, one side of the first protruding ring and one side of the second protruding ring are respectively slidingly abutted with the cylindrical protrusion, the other side of the first protruding ring is movably fitted with the notch at one end of the cylindrical protrusion, and the other side of the second protruding ring is movably fitted with the notch at the other end of the cylindrical protrusion.

5. The electric power assisted steering apparatus of claim 4, wherein The diameter of the first protruding ring is the same as the diameter of the second protruding ring, and the free ends of the rack protrude from the outer wall surfaces of the first protruding ring and the second protruding ring.

6. The electric power assisted steering apparatus of claim 4, wherein The root of the rack is provided with a reinforcing rib, and a groove is formed between the reinforcing rib, the first protruding ring and the second protruding ring.

7. The electric power assisted steering apparatus of claim 4, wherein The outer circumferential wall of the first protruding ring and the outer circumferential wall of the second protruding ring are respectively provided with annular grooves, wear-resistant rings are installed in the annular grooves, and the wear-resistant rings protrude from the annular grooves.

8. The electric power steering apparatus according to claim 3, characterized by The inner circumferential wall of the steering nut is provided with a flat groove for installing a return device and an inner raceway for rolling of the ball.

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