Long-distance electric adjusting steering column with double-lead-screw structure

Abstract

The invention discloses a long-distance electric adjusting steering column of a double-lead-screw structure. The long-distance electric adjusting steering column comprises a column body, an axial driving unit, a transmission mechanism and a connecting mechanism. The transmission mechanism comprises a first lead screw, a first lead screw nut, a second lead screw and a second lead screw nut, and the first lead screw is connected with the output end of the axial driving unit; the pipe column body comprises an inner pipe, a middle pipe and an outer pipe; the first lead screw nut is matched with the first lead screw, the output torque of the axial driving unit is transmitted through the first lead screw, the first lead screw nut enables the inner pipe and the middle pipe to slide relatively, the second lead screw nut is matched with the second lead screw, and the output torque of the axial driving unit is used for driving the middle pipe and the outer pipe to slide relatively. Long-distance stable adjustment of the steering column is achieved, and driving comfort and adjustment convenience are improved.

Description

Technical Field

[0001] This invention relates to the field of automotive steering technology, specifically to a long-distance electrically adjustable steering column with a dual-screw structure. Background Technology

[0002] In automotive design, the electric adjustment function of the steering column (including axial length and angle adjustment) is one of the key features for improving driving comfort. Most existing electric adjustable steering columns suffer from short adjustment ranges. With the increasing prevalence of intelligent driving, steering wheels will no longer be essential in the future, and in certain usage scenarios, they may need to be hidden, requiring electric adjustable columns with a larger axial adjustment range. The development of long-range electric adjustable columns has encountered drawbacks such as low transmission efficiency, large fluctuations in adjustment speed, insufficient structural stability, and large space requirements.

[0003] Specifically, such as Figure 8 As shown, the axial adjustment structure uses a relatively long lead screw to meet the long stroke adjustment range. Due to the limitations of existing processing technology, the coaxiality of the lead screw is difficult to control when it is too long, resulting in large fluctuations in the axial adjustment speed.

[0004] Specifically, such as Figure 9 As shown, a relatively long lead screw is used. Since the lead screw cannot be shortened, when the column is axially retracted to the shortest distance, the rear end of the lead screw will intrude into the space outside the column envelope, which is not conducive to the overall vehicle layout. Summary of the Invention

[0005] The technical problem this invention aims to solve is the shortcomings of electric adjustment of automotive steering columns, such as short travel, low transmission efficiency, large fluctuations in adjustment speed, insufficient structural stability, and large space occupation. The purpose of this invention is to provide a long-distance electric adjustment steering column, achieving stable adjustment over long distances and improving driving comfort and adjustment convenience.

[0006] To solve the above-mentioned technical problems, the present invention provides a long-distance electrically adjustable steering column with a dual lead screw structure, including a column body, an axial drive unit, a transmission mechanism, and a connecting mechanism; The transmission mechanism includes a first lead screw, a first lead screw nut, a second lead screw, and a second lead screw nut, wherein the first lead screw is connected to the output end of the axial drive unit; The tubular body includes an inner tube, a middle tube, and an outer tube. The inner tube is slidably fitted inside the middle tube, and the middle tube is slidably fitted inside the outer tube, for adjusting the axial length. The connecting mechanism includes an inner tube connecting bracket, an intermediate tube connecting bracket, and an outer tube connecting bracket; the inner tube connecting bracket is used to connect the inner tube to the first lead screw nut; the intermediate tube connecting bracket is used to connect the intermediate tube to the axial drive unit; the outer tube connecting bracket is used to connect the outer tube to the second lead screw, and at the same time provides guidance and support for the adjustment of the tube column body; The first lead screw nut engages with the first lead screw, enabling the output torque of the axial drive unit to be transmitted through the first lead screw. The first lead screw nut allows for relative sliding between the inner tube and the intermediate tube. The second lead screw is rigidly connected to the outer tube connecting bracket, and the axial drive unit is connected to the intermediate tube through the intermediate tube connecting bracket; the second lead screw nut cooperates with the second lead screw to realize the output torque of the axial drive unit to drive the relative sliding between the intermediate tube and the outer tube.

[0007] Preferably, the axial drive unit includes a motor and a reduction gear set; the reduction gear set is used to reduce the motor speed and increase the torque at the first output end and the second output end.

[0008] Preferably, the reduction gear set includes a three-stage transmission; the first stage transmission consists of a worm and a first intermediate gear; the second stage transmission consists of a first intermediate gear and a second intermediate gear; the third stage transmission consists of a second intermediate gear, a third-stage driven first gear, and a third-stage driven second gear; the second lead screw nut is coaxially fixed with the third-stage driven second gear, and the first lead screw is coaxially fixed with the third-stage driven first gear.

[0009] Preferably, the first intermediate gear includes a first-stage driven gear and a second-stage driving gear; the second intermediate gear includes a second-stage driven gear and a third-stage driving gear.

[0010] Preferably, the axial drive unit includes a housing and a housing cover; Preferably, the housing and housing cover have a first assembly tolerance compensation mechanism to ensure correct installation of the worm gear. The first assembly tolerance compensation mechanism includes an O-ring and a motor shaft bushing.

[0011] Preferably, the housing and housing cover have a second assembly tolerance compensation mechanism to ensure the correct installation of the second intermediate gear. The second assembly tolerance compensation mechanism includes a rubber pad and a metal gasket.

[0012] Preferably, the housing and housing cover have a third assembly tolerance compensation mechanism to ensure the correct installation of the second lead screw nut. The third assembly tolerance compensation mechanism includes an O-ring and a metal washer.

[0013] Preferably, the housing and housing cover have a fourth assembly tolerance compensation mechanism to ensure the correct installation of the first lead screw. The fourth assembly tolerance compensation mechanism includes a rubber pad and a metal gasket.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Stable adjustment speed: The axial drive unit uses a dual lead screw structure, which reduces the lead screw length compared to using a single lead screw, thus improving the stability of the axial adjustment speed.

[0015] 2. Small footprint: In the dual lead screw structure with axial drive unit, when axial adjustment is performed, the first lead screw rotates and moves axially relative to the second lead screw nut; the second lead screw does not rotate and does not move axially relative to the second lead screw nut. This achieves axial overlap of the two lead screws when the axial storage is at its limit, reducing the space occupied by the lead screws at the storage limit.

[0016] 3. Low noise adjustment: The three-stage transmission between the axial drive unit motor and the lead screw increases the adjustment space of the reduction ratio within the drive unit, reduces the output load at the motor end, reduces vibration and abnormal noise, and improves the overall NVH performance.

[0017] 4. Stable structure: The third-stage driven gears on the first and second lead screws are meshed with the third-stage driving gear through a double-gear split transmission method, which realizes the even distribution of the output load of the two third-stage driven gears and improves the stability of the structure.

[0018] 5. Improved durability: The drive unit adopts an assembly method in which the housing and housing cover are assembled along the lead screw axis, ensuring that the axis of each gear inside the drive unit is independently controlled by the housing, improving the control accuracy of the center distance of each gear and enhancing the durability of the drive unit. Attached Figure Description

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a schematic diagram of the electrically adjustable steering column structure in Example 1; Figure 2 This is a schematic diagram of the structure of the electrically adjustable steering column after it has been retracted in Example 1; Figure 3 This is an exploded view of the axial drive unit and transmission mechanism of Example 1; Figure 4 This is an exploded view of the axial drive unit in Example 1; Figure 5 This is a schematic diagram of the first intermediate gear in Example 1; Figure 6 This is a schematic diagram of the second intermediate gear in Example 1; Figure 7 This is a schematic diagram of the first lead screw in Example 1; Figure 8 This is a schematic diagram of an existing electrically adjustable steering column; Figure 9 This is a schematic diagram of the existing electric adjustable steering column after it has been retracted. Detailed Implementation

[0020] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can fully understand other advantages and technical effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments, and the details in this specification can also be applied based on different viewpoints, with various modifications or changes made without departing from the overall design concept of the invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. The following exemplary embodiments of the present invention can be implemented in many different forms and should not be construed as being limited to the specific embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary embodiments to those skilled in the art. Example 1

[0021] like Figures 1 to 7 As shown, this embodiment provides a long-distance electrically adjustable steering column with a dual-screw structure, including a column body, an axial drive unit 7, a transmission mechanism, and a connecting mechanism; The transmission mechanism includes a first lead screw 9, a first lead screw nut 8, a second lead screw 10, and a second lead screw nut 21. The first lead screw 9 is connected to the output end of the axial drive unit 7. The tubular body includes an inner tube 1, a middle tube 2, and an outer tube 3. The inner tube 1 is slidably fitted inside the middle tube 2, and the middle tube 2 is slidably fitted inside the outer tube 3, for adjusting the axial length. The connecting mechanism includes an inner tube connecting bracket 4, an intermediate tube connecting bracket 5, and an outer tube connecting bracket 6; the inner tube connecting bracket 4 is used to connect the inner tube 1 to the first lead screw nut 8; the intermediate tube connecting bracket 5 is used to connect the intermediate tube 2 to the axial drive unit 7; the outer tube connecting bracket 6 is used to connect the outer tube 3 to the second lead screw 10, and at the same time provides guidance and support for the adjustment of the tube column body. The first lead screw nut 8 engages with the first lead screw 9 via a trapezoidal thread, enabling the output torque of the axial drive unit 7 to be transmitted through the first lead screw 9. The first lead screw nut 8 allows for relative sliding between the inner tube 1 and the intermediate tube 2. The second lead screw 10 is rigidly connected to the outer tube connecting bracket 6, and the axial drive unit 7 is connected to the intermediate tube 2 through the intermediate tube connecting bracket 5; the trapezoidal thread of the second lead screw nut 21 cooperates with the second lead screw 10 to realize the output torque of the axial drive unit 7 to drive the relative sliding between the intermediate tube 2 and the outer tube 3.

[0022] The axial drive unit 7 includes a motor 20 and a reduction gear set; the reduction gear set is used to reduce the speed of the motor 20 and increase the torque at the first output end and the second output end.

[0023] The reduction gear set includes a three-stage transmission; the first stage transmission consists of a worm gear 19 and a first intermediate gear 18; the second stage transmission consists of a first intermediate gear 18 and a second intermediate gear 16; and the third stage transmission consists of a second intermediate gear 16, a third-stage driven first gear, and a third-stage driven second gear 32. The second lead screw nut 21 is coaxially fixed to the third-stage driven second gear 32, and the first lead screw 9 is coaxially fixed to the third-stage driven first gear 31. Two third-stage driven gears, namely the third-stage driven second gear 32 and the third-stage driven first gear 31, are provided to evenly distribute the load of the drive column axial adjustment onto the two third-stage driven gears, thereby improving structural stability.

[0024] The tubular column is folded down to its shortest possible length, such as... Figure 2 As shown, the first lead screw 9 and the second lead screw 10 can overlap in length to reduce the space occupied by the lead screws at the storage limit. Preferably, as shown... Figure 5 and Figure 6 As shown, the first intermediate gear 18 includes a first-stage driven gear 26 and a second-stage driving gear 25; the second intermediate gear 16 includes a second-stage driven gear 29 and a third-stage driving gear 28.

[0025] The axial drive unit 7 includes a housing 11 and a housing cover 17.

[0026] The housing 11 and the housing cover have independent positioning features to position the axis of the worm gear 19, and are designed with a first assembly tolerance compensation mechanism, including an O-ring 14 and a motor 20 shaft bushing 15, to ensure that the worm gear 19 is installed correctly.

[0027] The housing 11 and housing cover 17 have independent positioning features to position the axis of the second intermediate gear 16, and are designed with a second assembly tolerance compensation mechanism, including a rubber pad 22 and a small metal shim 23, to ensure that the second intermediate gear 16 is installed correctly.

[0028] The housing 11 and housing cover 17 have independent positioning features to position the axis of the second lead screw nut 21, and are designed with a third assembly tolerance compensation mechanism, including O-ring 12-large and metal washer 13-large, to ensure that the second lead screw nut 21 is installed correctly.

[0029] The housing 11 and housing cover 17 have independent positioning features to position the axis of the first lead screw 9, and are designed with a fourth assembly tolerance compensation mechanism, including a rubber pad 22 and a small metal washer 23, to ensure the correct installation of the first lead screw 9. The present invention has been described in detail above through specific embodiments and examples, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A long-distance electrically adjustable steering column with a dual-screw structure, characterized in that, It includes the tubular column body, axial drive unit, transmission mechanism, and connecting mechanism; The transmission mechanism includes a first lead screw, a first lead screw nut, a second lead screw, and a second lead screw nut, wherein the first lead screw is connected to the output end of the axial drive unit; The tubular body includes an inner tube, a middle tube, and an outer tube. The inner tube is slidably fitted inside the middle tube, and the middle tube is slidably fitted inside the outer tube, for adjusting the axial length. The connecting mechanism includes an inner tube connecting bracket, an intermediate tube connecting bracket, and an outer tube connecting bracket; the inner tube connecting bracket is used to connect the inner tube to the first lead screw nut; the intermediate tube connecting bracket is used to connect the intermediate tube to the axial drive unit; the outer tube connecting bracket is used to connect the outer tube to the second lead screw, and at the same time provides guidance and support for the adjustment of the tube column body; The first lead screw nut engages with the first lead screw, enabling the output torque of the axial drive unit to be transmitted through the first lead screw. The first lead screw nut allows for relative sliding between the inner tube and the intermediate tube. The second lead screw is rigidly connected to the outer tube connecting bracket, and the axial drive unit is connected to the intermediate tube through the intermediate tube connecting bracket; the second lead screw nut cooperates with the second lead screw to realize the output torque of the axial drive unit to drive the relative sliding between the intermediate tube and the outer tube.

2. The electrically adjustable steering column according to claim 1, characterized in that, The axial drive unit includes a motor and a reduction gear set; the reduction gear set is used to reduce the motor speed and increase the torque at the first output end and the second output end.

3. The electrically adjustable steering column according to claim 2, characterized in that, The reduction gear set includes a three-stage transmission; the first stage transmission consists of a worm and a first intermediate gear; the second stage transmission consists of a first intermediate gear and a second intermediate gear; the third stage transmission consists of a second intermediate gear, a third-stage driven first gear, and a third-stage driven second gear; the second lead screw nut is coaxially fixed with the third-stage driven second gear, and the first lead screw is coaxially fixed with the third-stage driven first gear.

4. The electrically adjustable steering column according to claim 3, characterized in that, The first intermediate gear includes a first-stage driven gear and a second-stage driving gear; the second intermediate gear includes a second-stage driven gear and a third-stage driving gear.

5. The electrically adjustable steering column according to claim 3, characterized in that, The axial drive unit includes a housing and a housing cover; the housing and housing cover have a first assembly tolerance compensation mechanism to ensure the worm gear is installed correctly.

6. The electrically adjustable steering column according to claim 5, characterized in that, The first assembly tolerance compensation mechanism includes an O-ring and a motor shaft bushing.

7. The electrically adjustable steering column according to claim 3, characterized in that, The axial drive unit includes a housing and a housing cover; the housing and housing cover have a second assembly tolerance compensation mechanism to ensure the correct installation of the second intermediate gear.

8. The electrically adjustable steering column according to claim 7, characterized in that, The second assembly tolerance compensation mechanism includes a rubber pad and a metal pad.

9. The electrically adjustable steering column according to claim 3, characterized in that, The axial drive unit includes a housing and a housing cover; the housing and housing cover have a third assembly tolerance compensation mechanism to ensure the correct installation of the second lead screw nut.

10. The electrically adjustable steering column according to claim 9, characterized in that, The third assembly tolerance compensation mechanism includes O-rings and metal gaskets.

11. The electrically adjustable steering column according to claim 3, characterized in that, The axial drive unit includes a housing and a housing cover; the housing and housing cover have a fourth assembly tolerance compensation mechanism to ensure the correct installation of the first lead screw.

12. The electrically adjustable steering column according to claim 11, characterized in that, The fourth assembly tolerance compensation mechanism includes rubber pads and metal gaskets.

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