Automobile steering knuckle master pin bushing and preparation process

Abstract

The invention relates to an automobile steering knuckle master pin bush and a preparation technology. The master pin bush comprises a bush outer wall, a middle layer and a bush inner wall. The lining outer wall, the middle layer and the lining inner wall are arranged from outside to inside; compared with a copper alloy bush, the kingpin bush has the advantages that the kingpin bush is resistant to oxidation corrosion and not prone to adhesive abrasion with a steering knuckle kingpin, and the friction coefficient of the kingpin bush is 53% lower than that of copper alloy under the grease lubrication condition; the kingpin bush can adapt to grease lubrication, can also adapt to oil lubrication, and can adapt to the dry friction condition of short-term oil shortage. According to market verification, the kingpin bush completely meets the requirements of the kingpin for severe working conditions such as abrasive wear caused by heavy load, low speed, high temperature and impurities, and the kingpin part of the kingpin is free of maintenance all the time.

Description

Technical Field

[0001] The invention relates to the technical field of automobile parts manufacturing, in particular to an automobile steering knuckle kingpin bushing and a preparation process thereof. Background Art

[0002] In actual application, bushings need to bear radial and axial loads in multiple directions, and have high requirements for bushing wear-resistant layer and strength. In particular, the working conditions of the steering knuckle kingpin and bushing are bad, and there are many after-sales wear and tear failures. For example, crawler-driven machinery such as excavators, bulldozers, cranes, etc., when supported by JF-800 bimetallic bearings, bears a large pressure. After long-term observation, it is found that after local wear of JF-800 bearings, abrasive particles will be produced, and abrasive particles will produce sanding in the oil. The bushing enters a rapid wear stage, and eventually oil leakage, abnormal noise, temperature rise, and large machine movement resistance will occur. The failure forms of the kingpin are mostly manifested as oxidation corrosion, abrasive wear, and adhesive wear. Obvious corrosion pits, corrosion products, and scratches caused by abrasive wear can be seen; the bushing is mainly manifested as adhesive wear and abrasive wear of the copper alloy layer.

[0003] With the development of lightweight vehicles and polymer materials, plastic sliding bearings are gradually replacing metal-based sliding bearings, with better application performance and can replace some rolling bearings, achieving special use effects. At present, engineering plastics are widely used in camshaft bushings, shoe pin bushings, roller bushings and kingpin bushings in bridge factories at home and abroad. Based on this, in order to reduce the abrasive wear trend of the kingpin and copper alloy bushing and increase the service life, it is necessary to develop a kingpin bushing with good wear resistance that can adapt to heavy-load and low-speed conditions. Summary of the invention

[0004] The purpose of the present invention is to provide a kingpin bushing for an automobile steering knuckle and a preparation process thereof in view of the deficiencies in the prior art.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] A kingpin bushing for a steering knuckle of an automobile comprises a bushing outer wall, an intermediate layer and a bushing inner wall; the bushing outer wall, the intermediate layer and the bushing inner wall are arranged from outside to inside.

[0007] As a further illustration of the invention, a plurality of oil pits are provided on the inner wall of the bushing.

[0008] As a further description of the invention, the kingpin bushing is a plastic kingpin bushing; the plastic kingpin bushing is made of modified nylon.

[0009] As a further description of the invention, the interference of the outer diameter of the plastic kingpin bushing is 0.2 mm, and the clearance between the inner diameter of the plastic kingpin bushing and the steering knuckle kingpin is 0.05-0.08 mm.

[0010] As a further description of the invention, the kingpin bushing is a steel-back kingpin bushing; the outer wall of the bushing is made of steel, the middle layer is made of copper powder, and the inner wall of the bushing is made of modified nylon.

[0011] As a further illustration of the invention, the thickness of the intermediate layer is 0.25-0.35 mm, and the thickness of the inner wall of the bushing is 0.4-0.6 mm.

[0012] As a further illustration of the invention, the clearance between the inner diameter of the steel back kingpin bushing and the steering knuckle kingpin is 0.05-0.1 mm.

[0013] The invention discloses a preparation process of a kingpin bushing of an automobile steering knuckle. The preparation process of the plastic kingpin bushing comprises: heating and drying modified nylon particles, and then performing injection molding.

[0014] A preparation process for a kingpin bushing of an automobile steering knuckle. The preparation process of the steel-back kingpin bushing is as follows: placing a steel substrate, laying copper powder on the steel substrate, heating it to 850-900°C in a mesh belt furnace, sintering it for 1-2 hours, laying modified nylon particles on the surface of the copper powder layer, heating it to 240-280°C, rolling it, heating it to 100-200°C during rolling, cooling it, slitting it, cutting it, and finally rolling it.

[0015] The invention discloses a preparation process of modified nylon particles. The modified nylon particles are prepared by mixing polytetrafluoroethylene micropowder, nylon powder, graphite powder and glass fiber or carbon fiber modified by a silane coupling agent. When the glass fiber accounts for 22%-28%, the polytetrafluoroethylene micropowder accounts for 2%-8%, the graphite powder accounts for 2%-8% and the nylon powder accounts for 62%-68%; when the carbon fiber accounts for 7%-13%, the polytetrafluoroethylene micropowder accounts for 2%-8%, the graphite powder accounts for 2%-8% and the nylon powder accounts for 77%-83%.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects:

[0017] Compared with copper alloy bushings, the kingpin bushing of the present invention has the advantages of being resistant to oxidation corrosion and not prone to adhesive wear with the steering knuckle kingpin. Under grease lubrication conditions, its friction coefficient is 53% lower than that of copper alloy.

[0018] The kingpin bushing of the present invention can adapt to grease lubrication, oil lubrication, and dry friction conditions due to a short-term lack of oil.

[0019] The kingpin bushing of the present invention has been verified by the market to fully meet the requirements of the steering knuckle kingpin facing severe working conditions such as heavy load and low speed, high temperature, and abrasive wear caused by impurities, thereby achieving lifelong maintenance-free of the steering knuckle kingpin. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 is a schematic diagram of material layup of a steel backing bushing of the present invention;

[0022] Figure 3 It is an expanded view of the inner wall of the bushing of the present invention.

[0023] In the figure, 1, pin bushing; 2, bushing outer wall; 3, middle layer; 4, bushing inner wall; 5, oil pit. DETAILED DESCRIPTION

[0024] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0025] Example 1

[0026] like Figure 1 , 3 As shown, this embodiment provides a kingpin bushing for a steering knuckle of an automobile. The kingpin bushing 1 includes a bushing outer wall 2, an intermediate layer 3 and a bushing inner wall 4. The bushing outer wall 2, the intermediate layer 3 and the bushing inner wall 4 are arranged from outside to inside.

[0027] When the kingpin bushing 1 is a plastic kingpin bushing, the plastic kingpin bushing is made of modified nylon. That is, the bushing outer wall 2, the middle layer 3 and the bushing inner wall 4 are made of the same material. The inner wall of the plastic kingpin bushing is not provided with an oil pit, but may be provided with a plurality of oil channels.

[0028] The interference of the outer diameter of the plastic kingpin bushing is 0.2mm, and the clearance between the inner diameter of the plastic kingpin bushing and the steering knuckle kingpin is 0.05-0.08mm. According to the linear expansion coefficients of the mixed modified nylon granules in the vertical and horizontal directions under the working conditions of 80-220℃, the vertical error does not exceed 6E-5, and the horizontal error does not exceed 2.5E-5. Through continuous optimization and calculation analysis, the interference of the outer diameter of the plastic kingpin bushing is preferably 0.2mm, and the clearance between the inner diameter of the plastic kingpin bushing and the steering knuckle kingpin is 0.05-0.08mm;

[0029] This embodiment also provides a preparation process of a kingpin bushing for a steering knuckle of an automobile. The preparation process of the plastic kingpin bushing is as follows: heating and drying the modified nylon particles, and then performing injection molding. The plastic kingpin bushing prepared in this way can be used for a steering knuckle kingpin of 2t or less.

[0030] Example 2

[0031] like Figure 1-3As shown, this embodiment provides a kingpin bushing for a steering knuckle of an automobile. The kingpin bushing 1 includes a bushing outer wall 2, an intermediate layer 3 and a bushing inner wall 4. The bushing outer wall 2, the intermediate layer 3 and the bushing inner wall 4 are arranged from outside to inside.

[0032] The inner wall 4 of the bushing is provided with a plurality of oil pits 5; in addition, a plurality of oil channels may also be provided.

[0033] When the kingpin bushing 1 is a steel back kingpin bushing, the bushing outer wall 2 is made of steel, the middle layer 3 is made of copper powder, and the bushing inner wall 4 is made of modified nylon. That is, the bushing outer wall 2, the middle layer 3 and the bushing inner wall 4 are made of different materials.

[0034] The thickness of the middle layer is 0.25-0.35 mm, and the thickness of the inner wall of the bushing is 0.4-0.6 mm.

[0035] The clearance between the inner diameter of the steel back kingpin bushing and the steering knuckle kingpin is 0.05-0.1mm. According to the linear expansion coefficients of the mixed modified nylon granules in the vertical and horizontal directions under the working conditions of 80-220℃, the vertical error does not exceed 6E-5, and the horizontal error does not exceed 2.5E-5. The calculation and analysis are continuously optimized, so that the clearance between the inner diameter of the steel back kingpin bushing and the steering knuckle kingpin is preferably 0.05-0.1mm.

[0036] This embodiment also provides a preparation process for a kingpin bushing of an automobile steering knuckle. The preparation process for a steel-backed kingpin bushing is as follows: a steel substrate is placed, copper powder is laid on the steel substrate, preferably, the copper powder is suspended at 60-80 mesh, and then heated to 850-900°C in a mesh belt furnace for 1-2 hours for sintering, and then modified nylon particles are laid on the surface of the copper powder layer, heated to 240-280°C, and rolled, and the rolling process needs to be heated to 100-200°C, and then cooled, slit, cut, and finally rolled. Among them, the sintering process is obtained through continuous experimentation and optimization.

[0037] In the above-mentioned embodiment 1 and embodiment 2, a preparation process of modified nylon particles is also provided. The modified nylon particles are prepared by blending polytetrafluoroethylene powder, nylon powder, graphite powder and glass fiber or carbon fiber modified by a silane coupling agent; wherein, when the glass fiber is 22%-28%, the polytetrafluoroethylene powder is 2%-8%, the graphite powder is 2%-8%, and the nylon powder is 62%-68%; when the carbon fiber is 7%-13%, the polytetrafluoroethylene powder is 2%-8%, the graphite powder is 2%-8%, and the nylon powder is 77%-13%. 83%; the preparation process can adopt drum mixing, granulation, drying and storage; the preferred components are: 5% polytetrafluoroethylene powder, 25% glass fiber modified by silane coupling agent or 10% carbon fiber, 5% graphite powder, nylon powder can adopt nylon 46 and select 65% or 80% according to glass fiber and carbon fiber respectively; wherein, the added glass fiber is mainly used to enhance the strength of the substrate and improve the dimensional stability of the bushing; the added silane coupling agent is mainly used to improve the bonding strength between the glass fiber and the substrate.

[0038] The plastic kingpin bushing and steel-back kingpin bushing manufactured by the above preparation process are installed by pressing at room temperature with the knuckle kingpin. The operating temperature range is -40-175°C, the maximum static load is 250N / mm2, the maximum dynamic load is 140N / mm2, and the dry friction coefficient of the modified nylon does not exceed 0.2.

[0039] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0040] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0041] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A kingpin bushing for a steering knuckle of an automobile, characterized in that: The kingpin bushing comprises a bushing outer wall, an intermediate layer and a bushing inner wall; the bushing outer wall, the intermediate layer and the bushing inner wall are arranged from outside to inside.

2. The automotive steering knuckle kingpin bushing according to claim 1, characterized in that: The inner wall of the bushing is provided with a plurality of oil pits.

3. The automotive steering knuckle kingpin bushing according to claim 1, characterized in that: The kingpin bushing is a plastic kingpin bushing; the plastic kingpin bushing is made of modified nylon.

4. The automotive steering knuckle kingpin bushing according to claim 3, characterized in that: The interference of the outer diameter of the plastic kingpin bushing is 0.2 mm, and the clearance between the inner diameter of the plastic kingpin bushing and the steering knuckle kingpin is 0.05-0.08 mm.

5. The automotive steering knuckle kingpin bushing according to claim 2, characterized in that: The kingpin bushing is a steel-backed kingpin bushing; the outer wall of the bushing is made of steel, the middle layer is made of copper powder, and the inner wall of the bushing is made of modified nylon.

6. The automotive steering knuckle kingpin bushing according to claim 5, characterized in that: The thickness of the middle layer is 0.25-0.35 mm, and the thickness of the inner wall of the bushing is 0.4-0.6 mm.

7. The automotive steering knuckle kingpin bushing according to claim 6, characterized in that: The clearance between the inner diameter of the steel back kingpin bushing and the steering knuckle kingpin is 0.05-0.1 mm.

8. A process for preparing a kingpin bushing for a steering knuckle of an automobile, comprising the kingpin bushing for a steering knuckle of an automobile as claimed in any one of claims 3 to 4, characterized in that: The preparation process of the plastic kingpin bushing is: heating and drying modified nylon particles, and then performing injection molding.

9. A process for preparing a kingpin bushing for a steering knuckle of an automobile, comprising the kingpin bushing for a steering knuckle of an automobile as claimed in any one of claims 5 to 7, characterized in that: The preparation process of the steel-back kingpin bushing is as follows: placing a steel substrate, laying copper powder on the steel substrate, and then heating it to 850-900°C in a mesh belt furnace, sintering it for 1-2 hours, and then laying modified nylon particles on the surface of the copper powder layer, heating it to 240-280°C, and rolling it. The rolling process needs to be heated to 100-200°C, and then cooling, slitting, cutting, and finally rolling.

10. A process for preparing modified nylon particles, characterized in that: The modified nylon particles are prepared by blending polytetrafluoroethylene micropowder, nylon powder, graphite powder and glass fiber or carbon fiber modified by a silane coupling agent; wherein, when the glass fiber accounts for 22%-28%, the polytetrafluoroethylene micropowder accounts for 2%-8%, the graphite powder accounts for 2%-8%, and the nylon powder accounts for 62%-68%; when the carbon fiber accounts for 7%-13%, the polytetrafluoroethylene micropowder accounts for 2%-8%, the graphite powder accounts for 2%-8%, and the nylon powder accounts for 77%-83%.

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