A bearing bushing mechanism for reducing noise in a steering system and its assembly process

Abstract

The present invention relates to the technical field of key automotive parts, specifically a bearing bushing mechanism and its assembly process for steering system noise reduction, comprising a bushing body and a fluid, wherein the bushing body comprises an outer ring wall, an inner ring wall, an inlet, a one-way valve, a convex bulge, and a side convex bulge, wherein the inner ring wall is provided with a convex bulge and a side convex bulge, and a cavity structure is provided between the outer ring wall, the inner ring wall, the convex bulge, and the side convex bulge, wherein a fluid is injected into the cavity structure, the cavity structure is connected to the inlet, a one-way valve is provided in the inlet, the outer ring wall is interference-fitted with the housing of the reduction mechanism, and the inner ring wall is sleeved outside the bearing of the worm. Compared with the prior art, when the bearing changes in different positions, the fluid flows correspondingly in the cavity structure, thereby improving the damping and nonlinear stiffness, realizing the gap compensation, ensuring the better performance of the reduction mechanism, and reducing the structural noise itself. The present invention has the advantages of simple structure, low manufacturing cost, and easy disassembly and assembly.

Description

Technical Field

[0001] The invention relates to the technical field of key automobile parts, in particular to a bearing bushing mechanism for reducing the noise of a steering system and an assembly process thereof. Background Art

[0002] The steering system reduction mechanism amplifies the motor torque through the combination of worm gear and worm, thereby driving the rack to move to achieve the function of vehicle steering. As a power transmission and load-bearing unit, it is easy for parts to separate and collide under the conditions of reversing and bad roads, resulting in knocking noise, which can easily lead to customer discomfort and complaints, and even after-sales claims.

[0003] In order to ensure that the worm can rotate smoothly and reduce the tooth clearance between the worm wheel and the worm during movement, the bearings at both ends of the worm need to be set as different supports, with one end fixed and the other end loose. The bushing design of the loose end is particularly important.

[0004] At present, the design of the reduction mechanism bushing is mostly a combination of high-rigidity plastic and low-rigidity rubber. No matter how the technical solution is improved, the following problems exist: 1. The manufacturing and assembly accuracy is difficult to control, which can easily cause the worm movement to get stuck and generate noise; 2. There is a gap in the bushing itself, and there is a risk of knocking under reversing and bad road conditions; 3. After durability, there is a gap in the bushing itself, which generates noise; 4. The gap is initially eliminated through pin adjustment, but the no-load torque is too large, and even a stick-slip problem occurs.

[0005] Therefore, it is necessary to design a bearing bushing mechanism and its assembly process for steering system noise reduction, so as to improve damping and nonlinear stiffness, realize clearance compensation, and thus achieve noise reduction. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a bearing bushing mechanism and an assembly process thereof for reducing the noise of a steering system, so as to improve damping and nonlinear stiffness, realize clearance compensation, and thus achieve noise reduction.

[0007] In order to achieve the above-mentioned purpose, the present invention provides a bearing bushing mechanism for reducing noise in a steering system, comprising a bushing body and a fluid, wherein the bushing body comprises an outer ring wall, an inner ring wall, an inlet, a one-way valve, a convex bulge, and a side convex bulge, the inner ring wall is provided with a convex bulge and a side convex bulge, a cavity structure is provided between the outer ring wall, the inner ring wall, the convex bulge and the side convex bulge, the cavity structure is injected with fluid, the cavity structure is connected with the inlet, a one-way valve is provided in the inlet, the outer ring wall is interference fit with the reduction mechanism housing, and the inner ring wall is sleeved outside the bearing of the worm.

[0008] In the initial installation state, the bearing is against the convex bump, and there is a gap between the side convex bump and the bearing.

[0009] In the working state, when the worm is lifted up and compresses the convex bulge, the fluid in the convex bulge is squeezed and flows to the side convex bulge, the side convex bulge holds the bearing tightly, and the rigidity of the bushing body increases. When the worm falls, the volume of the convex bulge increases and the pressure decreases, the fluid in the side convex bulge flows back to the convex bulge, and the worm returns to the initial installation position, solving the problem of existing bushing sticking.

[0010] When the worm gear wears and causes the worm to fall, the convex bump is squeezed by the fluid and expands downward, eliminating the gap between the bushing body and the bearing.

[0011] A sealing plug is also provided in the inlet, and the sealing plug is located outside the one-way valve, and the sealing plug is threadedly matched with the inner wall of the inlet.

[0012] The convex bulge and the side convex bulge are both symmetrical with respect to the center line of the bushing body. The convex bulge is located above the bearing, and the side convex bulge is located on the left and right sides of the bearing.

[0013] The wall thickness of the convex hull and the side convex hull is smaller than the wall thickness of the outer annular wall and the inner annular wall.

[0014] The fluid includes one or more combination of air, inert gas and industrial grease. Solid medium is added into the fluid.

[0015] An assembly process for a bearing bushing mechanism for reducing noise in a steering system comprises the following steps: step 1, pre-storing fluid in a cavity structure until the pressure in the cavity structure is 0.5 to 1 times of an initial design pressure P; step 2, pressing a bushing body pre-storing fluid into a corresponding position of a reducer housing, and installing a worm connected to a bearing into a corresponding position of the reducer housing; step 3, detecting the pressure p in the bushing body cavity structure, if the pressure p is less than the initial design pressure P, pressing fluid into the bushing body through a fluid supply system until the pressure p reaches the initial design pressure P; if the pressure p is greater than the initial design pressure P, allowing the fluid in the bushing body to flow out, and then pressing fluid into the bushing body through the fluid supply system until the pressure p reaches the initial design pressure P.

[0016] The calculation formula of the initial design pressure P is P = F / S, F is the design preload of the bushing body on the worm, and S is the contact area between the convex hull of the bushing body and the bearing.

[0017] The method further comprises step 4 of blocking the inlet of the bushing body with a sealing plug.

[0018] The fluid supply system comprises a fluid container, a constant pressure pump system, a pressure gauge and a valve. The input end of the constant pressure pump system is connected to the fluid container, and the output end of the constant pressure pump system is provided with a pressure gauge and a valve.

[0019] Compared with the prior art, the present invention designs a bearing bushing mechanism and its assembly process for steering system noise reduction. When the bearing position changes, the fluid flows in the cavity structure accordingly, which improves the damping and nonlinear stiffness, realizes the gap compensation, ensures the better performance of the speed reduction mechanism, and reduces the structural noise itself. The present invention has the advantages of simple structure, low manufacturing cost, and easy disassembly and assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is an axonometric view of the bearing bushing mechanism of the present invention.

[0021] Figure 2 It is a cross-sectional view of the bearing bushing mechanism of the present invention.

[0022] Figure 3 The cross-sectional view of the bearing bushing mechanism of the present invention after assembly Figure 1 .

[0023] Figure 4 The cross-sectional view of the bearing bushing mechanism of the present invention after assembly Figure 2 .

[0024] Figure 5 It is a schematic diagram of the nonlinear stiffness of the bearing bushing mechanism of the present invention.

[0025] Figure 6 Schematic diagram of the fluid supply system used in the present invention. DETAILED DESCRIPTION

[0026] The present invention will now be further described with reference to the accompanying drawings.

[0027] See also Figures 1 to 4 The present invention provides a bearing bushing mechanism for reducing noise in a steering system, comprising a bushing body and a fluid. The bushing body 3 comprises an outer ring wall 8, an inner ring wall 9, an inlet 7, a one-way valve 2, a convex bulge 10, and a side convex bulge 11. The inner ring wall 9 is provided with a convex bulge 10 and a side convex bulge 11. A cavity structure is provided between the outer ring wall 8, the inner ring wall 9, the convex bulge 10, and the side convex bulge 11. Fluid is injected into the cavity structure. The cavity structure is connected to the inlet 7. A one-way valve 2 is provided in the inlet 7 to prevent fluid leakage and ensure that the fluid in the cavity structure is maintained at a certain pressure. The outer ring wall 8 is interference-fitted with the reduction mechanism housing 6, and the inner ring wall 9 is sleeved outside the bearing 4 of the worm 5.

[0028] In the initial installation state, the bearing 4 abuts against the convex bump 10 , and there is a gap between the side convex bump 11 and the bearing 4 . Such a structure can compensate and eliminate the tooth clearance of the worm and worm wheel.

[0029] In the working state, when the worm 5 is lifted up and compresses the convex bulge 10, the fluid in the convex bulge 10 is squeezed and flows to the side convex bulge 11, and the side convex bulge 11 holds the bearing 4 tightly, and the rigidity of the bushing body 3 is increased, showing good nonlinearity. When the worm 5 falls, the volume of the convex bulge 10 increases and the pressure decreases, and the fluid in the side convex bulge 11 flows back to the convex bulge 10, and the worm 5 returns to the initial installation position.

[0030] When the worm wheel wears and causes the worm 5 to fall, the convex bump 10 is squeezed by the fluid and expands downward, eliminating the gap between the bushing body 3 and the bearing 4, and maintaining the low-noise operation of the entire reduction mechanism. Therefore, the self-adjusting function of the present invention solves the problem of gaps caused by wear in existing products.

[0031] A sealing plug 1 is also provided in the inlet 7, and the sealing plug 1 is located outside the one-way valve 2 to prevent the one-way valve 2 from failing. The sealing plug 1 is threadedly matched with the inner wall of the inlet 7, which ensures the sealing of the fluid and is easy to disassemble.

[0032] The convex bump 10 and the side convex bump 11 are both symmetrical with respect to the center line of the bushing body 3 . The convex bump 10 is located above the bearing 4 , and the side convex bump 11 is located on the left and right sides of the bearing 4 .

[0033] The wall thickness of the convex bump 10 and the side convex bump 11 is smaller than the wall thickness of the outer annular wall 8 and the inner annular wall 9. The wall thickness of the outer annular wall 8 and the inner annular wall 9 ensures sufficient strength and is not easily deformed under high pressure.

[0034] The fluid includes a combination of one or more media including air, inert gas, and industrial grease.

[0035] Solid medium is added into the fluid. During the vibration of the bushing body 3, the solid and the fluid medium rub against each other to dissipate energy, so that the bushing mechanism becomes a damper.

[0036] An assembly process of a bearing bushing mechanism for steering system noise reduction includes the following steps: Step 1, pre-storing fluid in a cavity structure until the pressure in the cavity structure is 0.5 to 1 times of the initial design pressure P. Pre-storing fluid in the bushing body is convenient for installation and can prevent parts from being damaged during installation; Step 2, pressing the bushing body with pre-storing fluid into the corresponding position of the reducer housing, and installing the worm connected with the bearing into the corresponding position of the reducer housing; Step 3, detecting the pressure p in the cavity structure of the bushing body. If the pressure p is less than the initial design pressure P, press the fluid into the bushing body through a fluid supply system until the pressure p reaches the initial design pressure P; if the pressure p is greater than the initial design pressure P, let the fluid in the bushing body flow out, and then press the fluid into the bushing body through the fluid supply system until the pressure p reaches the initial design pressure P. Step 4, using a sealing plug to block the entrance of the bushing body to prevent the runny nose from overflowing.

[0037] The calculation formula of the initial design pressure P is P=F / S, F is the design preload of the bushing body on the worm, and S is the contact area between the convex hull of the bushing body and the bearing.

[0038] See also Figure 6 The fluid supply system includes a fluid container 12, a constant pressure pump system 13, a pressure gauge 14, and a valve 15. The input end of the constant pressure pump system 13 is connected to the fluid container 12, and the output end of the constant pressure pump system 13 is provided with a pressure gauge 14 and a valve 15.

[0039] The present invention is carried out according to the above-mentioned assembly steps, and the operation is simple and the controllability is good. Example

[0040] In this embodiment, the fluid is air, the outer ring wall 8 of the bushing body 3 is interference fit with the speed reduction mechanism housing 6, the inner ring wall 9 is matched with the bearing 4 of the worm 5, and the inner ring of the bearing 4 is interference fit with the worm 5; air is injected into the cavity structure, and the inner ring wall 9 is provided with a convex bulge 10 located above the bearing 4 and two side convex bulges 11 located on the left and right sides of the bearing 4 to support the worm bearing. The convex bulge 10 is relatively large and its end face is elliptical.

[0041] In this example, the assembly steps of the bearing bushing mechanism are as follows:

[0042] Step 1: pre-store air in the cavity structure until the pressure inside the cavity structure is twice the initial design pressure P.

[0043] Step 2, press the bushing body pre-filled with air into the corresponding position of the reducer housing, and install the worm connected with the bearing into the corresponding position of the reducer housing.

[0044] Step 3, detect the pressure p in the cavity structure of the bushing body. If the pressure p is less than the initial design pressure P, air is pressed into the bushing body through the fluid supply system until the pressure p reaches the initial design pressure P; if the pressure p is greater than the initial design pressure P, the air in the bushing body is allowed to flow out, and then air is pressed into the bushing body through the fluid supply system until the pressure p reaches the initial design pressure P.

[0045] Step 4: Use a sealing plug to block the inlet of the bushing body to prevent air from escaping. Example

[0046] In this embodiment, the fluid is hydraulic oil in industrial grease, the outer ring wall 8 of the bushing body 3 is interference fit with the speed reduction mechanism housing 6, the inner ring wall 9 is matched with the bearing 4 of the worm 5, and the inner ring of the bearing 4 is interference fit with the worm 5; hydraulic oil is injected into the cavity structure, and the inner ring wall 9 is provided with a convex bulge 10 located above the bearing 4 and two side convex bulges 11 located on the left and right sides of the bearing 4 to support the worm bearing. The convex bulge 10 is relatively large and the end face is elliptical.

[0047] In this example, the assembly steps of the bearing bushing mechanism are as follows:

[0048] Step 1: pre-store hydraulic oil in the cavity structure until the pressure in the cavity structure is 0.5 times the initial design pressure P.

[0049] Step 2: press the bushing body pre-filled with hydraulic oil into the corresponding position of the reducer housing, and install the worm connected with the bearing into the corresponding position of the reducer housing.

[0050] Step 3, detect the pressure p in the cavity structure of the bushing body. If the pressure p is less than the initial design pressure P, pressurize hydraulic oil into the bushing body through the fluid supply system until the pressure p reaches the initial design pressure P; if the pressure p is greater than the initial design pressure P, let the hydraulic oil in the bushing body flow out, and then pressurize hydraulic oil into the bushing body through the fluid supply system until the pressure p reaches the initial design pressure P.

[0051] Step 4: Use a sealing plug to block the inlet of the bushing body to prevent the hydraulic oil from overflowing.

[0052] The above embodiments are designed based on the combination of fluidity and structural changes. Figure 5 The nonlinear stiffness ensures that the bushing provides lower stiffness under low torque so that the worm can rotate smoothly, and provides higher stiffness under high torque to compensate for the clearance of the worm and worm wheel.

Claims

1. A bearing bushing mechanism for reducing noise in a steering system, comprising a bushing body and a fluid, characterized in that: The bushing body (3) comprises an outer ring wall (8), an inner ring wall (9), an inlet (7), a one-way valve (2), a convex bulge (10), and a side convex bulge (11); the inner ring wall (9) is provided with a convex bulge (10) and a side convex bulge (11); a cavity structure is provided between the outer ring wall (8), the inner ring wall (9), the convex bulge (10), and the side convex bulge (11); a fluid is injected into the cavity structure; the cavity structure is connected to the inlet (7); a one-way valve (2) is provided in the inlet (7); the outer ring wall (8) is interference-fitted with a reduction mechanism housing (6); the inner ring wall (9) is sleeved outside a bearing (4) of a worm gear (5); in an initial installation state, the bearing (4) abuts against the convex bulge ( 10), there is a gap between the side convex bulge (11) and the bearing (4); in the working state, when the worm (5) is lifted and compresses the convex bulge (10), the fluid in the convex bulge (10) is squeezed and flows to the side convex bulge (11), the side convex bulge (11) holds the bearing (4), and the rigidity of the bushing body (3) increases; when the worm (5) falls, the volume of the convex bulge (10) increases and the pressure decreases, the fluid in the side convex bulge (11) flows back to the convex bulge (10), and the worm (5) returns to the initial installation position; after the worm (5) falls due to wear of the worm wheel, the convex bulge (10) is squeezed by the fluid and expands downward, thereby eliminating the gap between the bushing body (3) and the bearing (4).

2. A bearing bushing mechanism for reducing noise in a steering system according to claim 1, characterized in that: A sealing plug (1) is also provided in the inlet (7). The sealing plug (1) is located outside the one-way valve (2), and the sealing plug (1) is threadedly engaged with the inner wall of the inlet (7).

3. A bearing bushing mechanism for reducing noise in a steering system according to claim 1, characterized in that: The convex bump (10) and the side convex bump (11) are both symmetrical with respect to the center line of the bushing body (3); the convex bump (10) is located above the bearing (4), and the side convex bump (11) is located on the left and right sides of the bearing (4).

4. A bearing bushing mechanism for reducing noise in a steering system according to claim 1, characterized in that: The wall thickness of the convex bulge (10) and the side convex bulge (11) is smaller than the wall thickness of the outer annular wall (8) and the inner annular wall (9).

5. The bearing bushing mechanism for reducing noise in a steering system according to claim 1, characterized in that: The fluid includes a combination of one or more media selected from the group consisting of air, inert gas, and industrial grease.

6. A bearing bushing mechanism for reducing noise in a steering system according to claim 1 or 5, characterized in that: A solid medium is added into the fluid.

7. An assembly process of a bearing bushing mechanism for steering system noise reduction as claimed in claim 1, characterized in that: The method comprises the following steps: step 1, pre-storing fluid in a cavity structure until the pressure in the cavity structure is 0.5 to 1 times of an initial design pressure P; step 2, pressing a bushing body pre-storing fluid into a corresponding position of a reducer housing, and installing a worm connected with a bearing into a corresponding position of the reducer housing; step 3, detecting the pressure p in the bushing body cavity structure; if the pressure p is less than the initial design pressure P, pressing the fluid into the bushing body through a fluid supply system until the pressure p reaches the initial design pressure P; if the pressure p is greater than the initial design pressure P, allowing the fluid in the bushing body to flow out, and then pressing the fluid into the bushing body through the fluid supply system until the pressure p reaches the initial design pressure P.

8. The assembly process of a bearing bushing mechanism for steering system noise reduction according to claim 7, characterized in that: The calculation formula of the initial design pressure P is P = F / S, F is the design preload of the bushing body on the worm, and S is the contact area between the convex hull of the bushing body and the bearing.

9. The assembly process of a bearing bushing mechanism for steering system noise reduction according to claim 7, characterized in that: The method further comprises step 4 of blocking the inlet of the bushing body with a sealing plug.

10. The assembly process of a bearing bushing mechanism for steering system noise reduction according to claim 7, characterized in that: The fluid supply system comprises a fluid container (12), a constant pressure pump system (13), a pressure gauge (14), and a valve (15); the input end of the constant pressure pump system (13) is connected to the fluid container (12), and the output end of the constant pressure pump system (13) is provided with a pressure gauge (14) and a valve (15).

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