Steering gear and ball screw thereof

Abstract

The ball screw comprises a rod body, a first through hole is formed in the rod body in the axial direction, the first through hole penetrates through the end, used for being connected with a ball cup, of the rod body, the rod body is further provided with a second through hole, and one end of the second through hole penetrates through the end, away from the ball cup, of the first through hole to form a first opening; the other end of the second through hole extends to the surface of the body to form a second opening. When the nut is driven by the motor to drive the rod body to move through the ball, extruded airflow in the shell enters the first through hole from the second opening in the surface of the rod body and flows out of the first opening, or the extruded airflow flows in from the first opening and flows out of the second opening, and compared with a gap between the nut and the roller path, the gap between the nut and the roller path is smaller. The ventilation effect of the first through hole and the second through hole is better, so that airflow circulation in the left cavity and the right cavity is smooth, the stability of the air pressure in the sealing cavity of the shell is facilitated, and the situation that the air pressure difference causes large pressure to the dustproof cover and the clamp is prevented.

Description

Technical Field

[0001] The invention relates to the technical field of automobile steering gears, in particular to a steering gear and a ball screw thereof. Background Art

[0002] The main function of the automobile power steering is to assist the driver to reduce the force of steering the wheel, making driving more handy, and the quiet driving environment can make the driver feel relaxed and not get tired driving too early. Telescopic dust covers are installed at both ends of the power steering. When the power steering is working, the dust covers will be telescopic. Due to the sealing structure, low pressure or high pressure will be formed inside the dust cover to hinder the power steering. When the steering in the prior art is running, the input shaft is rotated to drive the pinion to rotate, and the pinion and the rack part on the ball screw are meshed to make the ball screw move linearly, thereby driving the inner and outer tie rods to move and rotate the tire to complete the steering work.

[0003] However, this structure may cause uneven air pressure in the sealing cavity of the shell and produce an air pressure difference during operation. The airflow at the left and right ends of the shell mainly passes through the gap between the nut and the screw raceway or between the nut steel balls. Due to the small gap, the air pressure on one side is always higher during the movement of the screw, which causes greater pressure on the dust cover and the clamp, accelerates the aging of the parts, and affects the life of the parts. At the same time, it will also affect the noise, vibration and harshness (NVH) of the entire steering gear, affecting the quality of the product to a certain extent. Summary of the invention

[0004] In response to the above technical problems, the present invention proposes a steering gear and a ball screw thereof. Compared with the gap between the nut and the raceway, the first through hole and the second through hole have better ventilation effect, so that the airflow in the left and right cavities flows smoothly, thereby helping to stabilize the air pressure inside the shell sealing cavity.

[0005] The technical solution adopted by the present invention is as follows: A ball screw for a steering gear includes a rod body, a first through hole is provided inside the rod body along the axial direction, the first through hole passes through one end of the rod body for connection with the ball head seat, the rod body is also provided with a second through hole, one end of the second through hole passes through the end of the first through hole away from the ball head seat to form a first opening, and the other end of the second through hole extends to the surface of the body to form a second opening.

[0006] Optionally, the outer peripheral wall of the rod body is provided with a spiral track for cooperating with a nut, and the spiral track is located between the first opening and the second opening.

[0007] Optionally, the rod body includes a first transmission section and a second transmission section connected to the first transmission section, the spiral track is provided on an outer peripheral wall of the first transmission section, and the second transmission section is provided with a rack for cooperating with a gear.

[0008] The present invention also discloses a steering gear, comprising a nut, a gear and the ball screw for the steering gear described above, wherein the nut cooperates with the spiral track on the outer peripheral wall of the first transmission section, the gear cooperates with the rack on the surface of the second transmission section, and the nut is located between the first opening and the second opening.

[0009] Optionally, it also includes a ball head seat, which includes a connecting block and a seat body, the connecting block cooperates with the first opening, the connecting block is provided with a third through hole, one end of the third through hole is connected to the first through hole, and the other end of the third through hole extends to the surface of the seat body to form a third opening.

[0010] Optionally, a groove cooperating with the spherical pull rod is provided at one end of the seat body away from the connecting block.

[0011] Optionally, it further includes a shell and a dust cover, the rod body is arranged inside the shell, one end of the dust cover is connected to the shell, and the other end of the dust cover is connected to the ball-type pull rod.

[0012] Optionally, the dust cover is a corrugated telescopic structure.

[0013] The beneficial effect of the present invention is that when the nut is driven by the motor to move the rod body through the ball, the squeezed airflow in the shell enters the first through hole from the second opening on the surface of the rod body and flows out from the first opening, or the squeezed airflow flows in from the first opening and flows out from the second opening. Compared with the gap between the nut and the raceway, the ventilation effect of the first through hole and the second through hole is better, so that the airflow in the left and right cavities flows smoothly, which helps to stabilize the air pressure inside the sealed cavity of the shell and prevent the air pressure difference from causing greater pressure on the dust cover and the clamp. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the structure of a ball screw for a steering gear provided in an embodiment of the present invention; Figure 2 A schematic diagram of a steering device provided in an embodiment of the present invention; Figure 3 It is a schematic diagram of the third through hole of the diverter proposed in an embodiment of the present invention.

[0015] The marks in the accompanying drawings are: 1. rod body; 11. first transmission section; 111. spiral track; 12. second transmission section; 121. rack; 2. first through hole; 21. first opening; 3. second through hole; 31. second opening; 4. nut; 5. ball head seat; 51. connecting block; 52. seat body; 6. third through hole; 7. spherical pull rod; 8. shell; 9. dust cover. DETAILED DESCRIPTION

[0016] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0017] like Figures 1 to 3 As shown, this embodiment discloses a ball screw for a steering gear, including a rod body 1, wherein a first through hole 2 is provided inside the rod body 1 along the axial direction, wherein the first through hole 2 penetrates one end of the rod body 1 for connecting with the ball head seat 5, and the rod body 1 is further provided with a second through hole 3, wherein one end of the second through hole 3 penetrates one end of the first through hole 2 away from the ball head seat 5 to form a first opening 21, and the other end of the second through hole 3 extends to the surface of the body to form a second opening 31. When the nut 4 is driven by the motor to drive the rod body 1 to move through the ball, the compressed airflow in the housing 8 enters the first through hole 2 from the second opening 31 on the surface of the rod body 1 and flows out from the first opening 21, or the compressed airflow flows in from the first opening 21 and flows out from the second opening 31. Compared with the gap between the nut 4 and the raceway, the ventilation effect of the first through hole 2 and the second through hole 3 is better, so that the airflow of the left and right cavities flows smoothly, thereby facilitating the stability of the air pressure inside the sealed cavity of the housing 8 and preventing the air pressure difference from causing a large pressure on the dust cover 9 and the clamp.

[0018] like Figure 1 As shown, the outer peripheral wall of the rod body 1 is provided with a spiral track 111 for cooperating with the nut 4, and the spiral track 111 is located between the first opening 21 and the second opening 31. The outer peripheral wall of the spiral track 111 is sleeved with a nut 4, and the nut 4 drives the rod body 1 to move left and right. The spiral track 111 is located between the first opening 21 and the second opening 31, that is, the nut 4 is located between the first opening 21 and the second opening 31, so that the airflow in the left and right cavities separated by the nut 4 can maintain a steady flow inside the housing 8 through the first opening 21 and the second opening 31. The rod body 1 includes a first transmission section 11 and a second transmission section 12 connected to the first transmission section 11, the outer peripheral wall of the first transmission section 11 is provided with the spiral track 111, and the second transmission section 12 is provided with a rack 121 for cooperating with a gear.

[0019] like Figure 2 and 3 As shown, this embodiment also discloses a steering gear, including a nut 4, a gear and a ball screw for the steering gear, wherein the nut 4 cooperates with the spiral track 111 on the outer peripheral wall of the first transmission section 11, and the gear cooperates with the rack 121 on the surface of the second transmission section 12, and the nut 4 is located between the first opening 21 and the second opening 31. The second opening 31 is located on the left side of the nut 4, and the first opening 21 is located on the right side of the nut 4. When the rod body 1 moves to the left, the airflow on the left side enters through the second opening 31 and flows out through the first opening 21. When the rod body 1 moves to the right, the airflow on the right side enters through the first opening 21 and flows out through the second opening 31.

[0020] like Figure 2As shown, it also includes a ball head seat 5, the ball head seat 5 includes a connecting block 51 and a seat body 52, the connecting block 51 cooperates with the first opening 21, the connecting block 51 is provided with a third through hole 6, one end of the third through hole 6 is connected to the first through hole 2, and the other end of the third through hole 6 extends to the surface of the seat body 52 to form a third opening. The airflow flows out or flows in from the third through hole 6 on the ball head seat 5.

[0021] like Figure 2 and 3 As shown, the end of the seat body 52 away from the connecting block 51 is provided with a groove that cooperates with the ball-type pull rod 7. It also includes a shell 8 and a dust cover 9. The rod body 1 is arranged inside the shell 8, one end of the dust cover 9 is connected to the shell 8, and the other end of the dust cover 9 is connected to the ball-type pull rod 7. The dust cover 9 is located at both ends of the shell 8, so that a sealed cavity is formed inside the shell 8. The dust cover 9 is a corrugated telescopic structure. When the pull rod moves left and right, the corrugated telescopic structure provides a telescopic space for the dust cover 9.

[0022] It is understandable 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 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 without contradictions or conflicts. All equivalent structural transformations made using the contents of the specification and drawings of the present invention, directly or indirectly used in other related technical fields, are similarly included in the protection scope of the present invention.

Claims

1. A ball screw for a steering gear, characterized in that: It includes a rod body, a first through hole is provided inside the rod body along the axial direction, the first through hole passes through one end of the rod body for connecting with the ball head seat, the rod body is also provided with a second through hole, one end of the second through hole passes through the end of the first through hole away from the ball head seat to form a first opening, and the other end of the second through hole extends to the surface of the body to form a second opening.

2. The ball screw for a steering gear according to claim 1, characterized in that: The outer peripheral wall of the rod body is provided with a spiral track for cooperating with a nut, and the spiral track is located between the first opening and the second opening.

3. The ball screw for a steering gear according to claim 2, characterized in that: The rod body includes a first transmission section and a second transmission section connected to the first transmission section. The outer peripheral wall of the first transmission section is provided with the spiral track, and the second transmission section is provided with a rack for cooperating with a gear.

4. A steering gear, characterized in that: It comprises a nut, a gear and a ball screw for a steering gear as claimed in claim 3, wherein the nut cooperates with the spiral track on the outer peripheral wall of the first transmission section, the gear cooperates with the rack on the surface of the second transmission section, and the nut is located between the first opening and the second opening.

5. The steering gear according to claim 4, characterized in that: It also includes a ball head seat, which includes a connecting block and a seat body. The connecting block cooperates with the first opening. The connecting block is provided with a third through hole. One end of the third through hole is connected to the first through hole, and the other end of the third through hole extends to the surface of the seat body to form a third opening.

6. The steering gear according to claim 5, characterized in that: One end of the seat body away from the connecting block is provided with a groove matched with the spherical pull rod.

7. The steering gear according to claim 4, characterized in that: It also includes a shell and a dust cover, the rod body is arranged inside the shell, one end of the dust cover is connected to the shell, and the other end of the dust cover is connected to the ball-type pull rod.

8. The steering gear according to claim 7, characterized in that: The dust cover is a corrugated telescopic structure.

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