Maintenance-free structure for axial clearance of automobile steering kingpin and assembly method of maintenance-free structure

Abstract

The invention discloses an axial clearance maintenance-free structure of an automobile steering main pin and an assembling method of the axial clearance maintenance-free structure of the automobile steering main pin. According to the axial clearance maintenance-free structure of the automobile steering main pin, an upper-section assembling structure and a lower-section assembling structure of the steering main pin are matched, and a steering knuckle and a steering fork head are assembled together; in the upper section assembly structure, the upper section of the main pin is assembled with a first assembly hole in the steering knuckle, an inner spline seat and an upper cover are arranged above the first assembly hole of the steering knuckle, a gland is screwed in a central blind hole in the top of the upper section of the main pin, an outer spline sliding block is arranged on the gland, and a belleville spring is assembled between the outer spline sliding block and the gland; in the lower section assembling structure, the lower section of the main pin is assembled with a second assembling hole in the steering knuckle, a supporting base is embedded in the bottom of the second assembling hole, two ball bowls are oppositely pressed in a cavity of the supporting base and a central blind hole in the bottom of the lower section of the main pin, and a steel ball is assembled between the two ball bowls. According to the invention, automatic adjustment of the axial clearance of the steering main pin is realized, and the purpose of ensuring the steering control stability of the vehicle is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of automobiles, in particular to an axial clearance maintenance-free structure of an automobile steering kingpin and an assembly method thereof. Background Art

[0002] In the automobile steering system, the role of the steering kingpin is to articulate the steering shaft and the steering knuckle, so that the steering knuckle swings around the kingpin to achieve wheel steering. The steering kingpin clearance of the automobile is an important indicator to ensure the steering performance of the vehicle. Too large a clearance will cause problems such as loose steering and vehicle shimmy, while too small a clearance will cause heavy steering and difficulty in steering return. It can be seen that the appropriate steering kingpin clearance can ensure smooth steering and excellent vehicle handling stability.

[0003] In the traditional automobile steering system structure, the automobile steering kingpin is usually composed of two parts: the upper kingpin section and the lower kingpin section, which are arranged on the steering fork. The upper kingpin section and the lower kingpin section of the steering kingpin are respectively assembled with the upper and lower coaxial pin holes of the steering knuckle through the bearing assembly; the pressure bearing or tapered roller bearing sleeved on the lower kingpin section is supported by the lower part of the steering knuckle to bear the axial load. At present, when assembling automobile axles, the axial clearance of the steering kingpin is generally adjusted by increasing or decreasing the thickness of the upper and lower gaskets of the bearing, so that the steering kingpin is assembled in an axial pre-interference manner, and it is expected that a certain axial clearance can be generated after loading and running. However, with the increase of vehicle mileage, the wear between the mating parts causes the axial clearance of the steering kingpin to continue to expand, so it needs to be maintained and adjusted regularly. In addition, the axial pre-interference assembly method increases the friction torque of the bearing, which will lead to poor lubrication of the bearing rolling elements and the inner and outer rings of the bearing. A large amount of heat will be generated due to dry friction, resulting in wear, bonding, and cracking of the inner and outer rings of the bearing, causing the bearing to heat up and be damaged. If the preload force is insufficient and the axial clearance is too large, it will cause greater vibration during vehicle operation, which will also shorten the service life of the bearing. Summary of the invention

[0004] The present invention provides a maintenance-free structure for the axial clearance of a steering kingpin of an automobile and an assembly method thereof, aiming to realize automatic adjustment of the axial clearance of the steering kingpin during the loading and operation of the vehicle through the optimized design of the assembly structure and the assembly method of the kingpin upper section and the kingpin lower section, so as to achieve the purpose of ensuring the steering control stability of the vehicle.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme: A maintenance-free structure for the axial clearance of a steering kingpin of an automobile. The steering knuckle and the steering fork in the steering system of the automobile are hingedly assembled together through the cooperation of the upper assembly structure and the lower assembly structure of the steering kingpin of the automobile. A central blind hole is respectively arranged at the top of the upper kingpin section and the bottom of the lower kingpin section. In the upper section assembly structure, the kingpin upper section is assembled with the first assembly hole on the steering knuckle, and a bearing is assembled between the kingpin upper section and the first assembly hole of the steering knuckle. An inner spline seat and an upper cover are arranged above the first assembly hole of the steering knuckle. The central blind hole at the top of the kingpin upper section is a threaded hole. A gland is screwed into the threaded hole to form a cavity between the gland and the upper cover. An outer spline slider is arranged on the gland. The outer spline slider cooperates with the inner spline seat to slide up and down in the cavity between the gland and the upper cover. A disc spring is assembled between the outer spline slider and the gland. In the lower section assembly structure, the kingpin lower section is assembled with the second assembly hole on the steering knuckle, and a bearing is assembled between the kingpin lower section and the second assembly hole of the steering knuckle. The second assembly hole is a stepped hole, and a support base is embedded in the bottom of the second assembly hole. The support base is provided with a cavity with an open upper portion. Two ball bowls are relatively pressed in the cavity of the support base and the bottom center blind hole of the kingpin lower section, and a steel ball is assembled between the two ball bowls.

[0006] The above-mentioned maintenance-free structure for the axial clearance of the automobile steering kingpin has an adjusting gasket installed between the inner spline seat and the upper end surface of the steering knuckle in the upper section assembly structure.

[0007] The above-mentioned maintenance-free structure for the axial clearance of the steering kingpin of the automobile has a lower adjusting gasket installed between the bottom of the cavity of the supporting base and the ball bowl assembled therewith in the lower section assembly structure.

[0008] The above-mentioned automobile steering kingpin axial clearance maintenance-free structure is provided with an adjustment process hole on the bottom surface of the support base.

[0009] In the above-mentioned maintenance-free structure for the axial clearance of the steering kingpin of the automobile, the number of disc springs assembled between the external spline slider and the gland is at least two, which are assembled in a combination mode of being overlapped in the same direction and in parallel.

[0010] In the above-mentioned maintenance-free structure for the axial clearance of the steering kingpin of an automobile, the bearings installed between the upper section of the kingpin and the first assembly hole and between the lower section of the kingpin and the second assembly hole are both needle bearings.

[0011] The above-mentioned maintenance-free structure for the axial clearance of the automobile steering kingpin, the upper cover and the inner spline seat are fixedly assembled with the steering knuckle by a group of bolts evenly arranged along the circumferential direction.

[0012] A maintenance-free assembly method for an automobile steering kingpin axial clearance structure is provided, wherein the axial assembly clearance of a steel ball is reserved in a kingpin lower section assembly structure, and a disc spring is pre-compressed in a kingpin upper section assembly structure, so as to realize automatic adjustment of the steering kingpin axial clearance during vehicle loading and operation. The specific operation steps are as follows: a. According to the force on the steering kingpin, calculate the maximum load that the steering kingpin can bear when the vehicle is fully loaded, and then set the preload and precompression s of the disc spring according to the characteristics of the disc spring; b. According to the vehicle load and the size chain relationship of each matching component, set the reserved gap x1 between the steel ball and the bottom ball bowl of the lower section of the kingpin, and calculate the theoretical thickness b1 of the lower adjustment gasket; c. Select a lower adjustment gasket with a thickness consistent with the theoretical thickness, place it at the bottom of the cavity of the support base, and press-fit a ball bowl with the opening facing upward into the cavity of the support base and the central blind hole at the bottom of the kingpin lower section. Place a steel ball in the ball bowl and place it in the central blind holes on the top surface of the kingpin upper section and the bottom surface of the kingpin lower section on the steering fork head. Rotary Press the cover and a ball bowl with the opening downward, and then assemble the steering fork head and the steering knuckle; d. Place the inner spline seat in the upper assembly structure of the kingpin above the first assembly hole of the steering knuckle, place the outer spline slider on the gland and assemble it with the inner spline seat, place the parallel superimposed combined disc spring on the gland in a free state, press the upper cover on the disc spring, select an upper adjustment gasket of appropriate thickness according to the pre-compression amount s of the disc spring, place it between the bottom surface of the inner spline seat and the upper end surface of the first assembly hole of the steering knuckle, and then fix the upper cover, the inner spline seat, the upper adjustment gasket and the steering knuckle with bolts; e. Adjust the axial clearance of the kingpin lower section. Use the detection tool to measure the actual clearance x2 between the steel ball and the bottom bowl of the kingpin lower section, calculate the difference Δ2 between the measured actual clearance x2 and the set reserved clearance x1, that is, Δ2 = x2- x1, and then calculate the actual thickness b2 of the lower adjustment gasket based on the Δ2 value; f. Disassemble the steering fork and steering knuckle, replace the adjustment gasket with a thickness dimension consistent with the calculated actual thickness b2, repeat steps c and d to complete the assembly process of the automobile steering kingpin axial clearance maintenance-free structure.

[0013] In the above-mentioned assembly method of the maintenance-free structure of the axial clearance of the automobile steering kingpin, in the step d, the thickness dimension of the upper adjusting gasket is determined by the following method: respectively measure the distance h1 between the upper end face of the inner spline seat and the upper end face of the first assembly hole of the steering knuckle, and the distance h2 between the bottom face of the upper cover and the upper end face of the first assembly hole of the steering knuckle, and calculate the difference Δ1 between h2 and h1, and accordingly determine that the thickness dimension w1 of the upper adjusting gasket is the difference between Δ1 and the pre-compression amount s of the disc spring, that is, w1=Δ1-s.

[0014] In the above-mentioned maintenance-free assembly method of the automobile steering kingpin axial clearance structure, in the step e, the actual thickness dimension b2 of the lower adjustment gasket is the difference between Δ2 and the theoretical thickness b1 of the lower adjustment gasket, that is, b2=Δ2- b1.

[0015] The present invention provides a maintenance-free structure for the axial clearance of a steering kingpin of an automobile, so that the axial load of the steering kingpin is borne by a steel ball of a lower section assembly structure, the steel ball is installed in a central blind hole of the lower section of the steering kingpin and two ball bowls at the lower part of the steering knuckle, and the axial clearance of the lower section of the steering kingpin can be ensured by increasing or decreasing the thickness of a lower adjustment gasket, so as to replace the axial pre-interference assembly structure of a pressure bearing or a tapered roller bearing in the prior art, thereby effectively avoiding the problem of over-tightening or over-loosening caused by improper axial pre-interference adjustment and the safety risks brought about thereby; in the maintenance-free structure for the axial clearance of the steering kingpin, the axial clearance of the upper section of the steering kingpin is maintenance-free adjusted by using two or more disc springs that are overlapped in the same direction in parallel, the disc spring has a variable stiffness characteristic of a small space and a large bearing capacity, and is arranged in a space formed by an upper cover and an outer spline slider, the outer spline slider and the inner spline seat are assembled by splines, and when the steering kingpin moves up and down, the outer spline teeth of the outer spline slider are driven to slide up and down along the inner spline groove of the inner spline seat.

[0016] The present invention also provides a method for assembling a maintenance-free structure of an automobile steering kingpin axial clearance. When assembling the steering knuckle and the steering fork head, the disc spring is pre-compressed by a certain stroke to generate a certain preload force. During the operation of the automobile, due to complex factors such as axial dynamic load impact or steel ball wear, the steering kingpin will move up and down and the axial clearance will change. The disc spring will be further compressed or rebounded on the basis of the pre-compression stroke to overcome the axial load impact and automatically compensate for the axial clearance, thereby realizing automatic adjustment of the steering kingpin axial clearance during the loading and operation of the vehicle, thereby achieving the purpose of ensuring the steering control stability of the vehicle.

[0017] The automobile steering kingpin axial clearance maintenance-free structure and assembly method thereof described in the present invention can be adapted to steering axles and steering drive axles of various types of automobiles, semi-trailers, and special equipment such as agricultural machinery, forestry machinery, and engineering machinery, and therefore has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional structural diagram of a maintenance-free structure of the axial clearance of the steering kingpin of an automobile; Figure 2 yes Figure 1 The enlarged view of the structure at position Ⅰ in the middle; Figure 3 yes Figure 1 A magnified view of the structure at center Ⅱ; Figure 4 It is a schematic diagram of the steering fork in the automobile steering system; Figure 5 It is a schematic diagram of the steering knuckle in the automobile steering system; Figure 6 It is a schematic diagram of the inner spline seat in the upper kingpin assembly structure; Figure 7It is a schematic diagram of the external spline slider in the kingpin upper section assembly structure; Figure 8 It is a schematic diagram of two opposing ball bowls and lower adjustment gasket in the kingpin lower section assembly structure; Fig. 9 , Fig.10 It is a schematic diagram of the assembly process of the disc spring and the upper adjustment gasket in the upper section assembly structure of the kingpin; Fig.11 , Fig.12 It is a schematic diagram of adjusting the thickness of the lower adjustment gasket in the kingpin lower section assembly structure.

[0019] Explanation of the symbols in the figure: 1 is the steering fork, 1-1 is the upper section of the main pin, 1-2 is the lower section of the main pin, and 1-3 is the center blind hole; 2 is a steering knuckle, 2-1 is a first assembly hole, and 2-2 is a second assembly hole; 3 is the steering shaft of the car; 4 is a bolt; 5 is a bearing; 6 is an upper adjustment gasket; 7 is an internal spline seat, 7-1 is an internal spline groove; 8 is a gland; 9 is an external spline slider, 9-1 is an external spline tooth; 10 is a disc spring; 11 is an upper cover; 12 is a support base, 12-1 is an adjustment process hole; 13 is a steel ball; 14 is a lower adjustment gasket; 15 is the ball bowl. DETAILED DESCRIPTION

[0020] The invention provides a maintenance-free structure for the axial clearance of a steering kingpin of an automobile and an assembly method thereof, which are suitable for automatically controlling the axial clearance of the steering kingpin of a steering axle and a steering drive axle of various automobiles, semi-trailers, and special equipment such as agricultural machinery, forestry machinery, and engineering machinery. The structure enables the axial load of the steering kingpin to be borne by a steel ball of a lower section assembly structure, and the steel ball is supported in two ball bowls at the lower section of the steering kingpin and the lower part of the steering knuckle. The axial clearance of the lower section of the steering kingpin can be ensured by increasing or decreasing the thickness of a lower adjustment gasket at the lower side of the steel ball bowl, so as to replace the axial pre-interference assembly structure of a pressure bearing or a tapered roller bearing in the prior art, thereby effectively avoiding the safety risks caused by over-tight or over-loose fitting of an axial pre-interference assembly method.

[0021] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0022] See Figure 1. Figure 2 , Figure 3 , Figure 4 , Figure 5 The present invention provides a maintenance-free structure for the axial clearance of an automobile steering kingpin, which hinges and assembles a steering knuckle 2 and a steering fork 1 in an automobile steering system together through the cooperation of an upper assembly structure and a lower assembly structure of the automobile steering kingpin; the inner side of the steering fork 1 is assembled with an automobile steering shaft 3, an upper kingpin section 1-1 is arranged at the upper end of the outer side of the steering fork 1, a lower kingpin section 1-2 is arranged at the lower end, and a center blind hole 1-3 is arranged at the top of the upper kingpin section 1-1 and the bottom of the lower kingpin section 1-2; a first assembly hole 2-1 is arranged at the upper end of the steering knuckle 2, and a second assembly hole 2-2 is arranged at the lower end of the steering knuckle 2.

[0023] See also Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 7 The automobile steering kingpin axial clearance maintenance-free structure of the present invention has an upper section assembly structure in which: the kingpin upper section 1-1 is assembled with the first assembly hole 2-1 on the steering knuckle 2, and a bearing 5 is assembled between the kingpin upper section 1-1 and the first assembly hole 2-1, and the bearing 5 is a needle bearing; an inner spline seat 7 and an upper cover 11 are arranged above the first assembly hole 2-1 of the steering knuckle 2, and the inner spline seat 7 and the upper cover 11 are fixedly installed on the steering knuckle 2 by a group of bolts 4 arranged along the circumferential direction, and an adjusting gasket 6 is assembled between the inner spline seat 7 and the upper end surface of the steering knuckle 2; The central blind hole at the top of the kingpin upper section 1-1 is preferably a threaded hole, in which a pressure cover 8 is screwed into the threaded hole to form a cavity between the pressure cover 8 and the upper cover 11; an external spline slider 9 is arranged on the pressure cover 8, and the external spline teeth 9-1 of the external spline slider 9 cooperate with the internal spline groove 7-1 of the internal spline seat 7 to provide a guiding effect for the external spline slider 9, so that the external spline slider 9 can slide up and down in the cavity between the pressure cover 8 and the upper cover 11, and a disc spring 10 is assembled between the external spline slider 9 and the pressure cover 8; the disc spring 10 is preferably two pieces, which are assembled in a combination of parallel overlapping in the same direction.

[0024] See also Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 8The maintenance-free structure of the axial clearance of the automobile steering kingpin described in the present invention has a lower section assembly structure in which the kingpin lower section 1-2 is assembled with the second assembly hole 2-2 on the steering knuckle 2, and a bearing 5 is assembled between the kingpin lower section 1-2 and the second assembly hole 2-2, and the bearing 5 is a needle bearing; the second assembly hole 2-2 of the steering knuckle 2 is a stepped hole, and a support base 12 is embedded at the bottom of the second assembly hole 2-2; the support base 12 is provided with a cavity with an upper opening, and two ball bowls 15 are relatively pressed in the cavity of the support base 12 and the bottom center blind hole of the kingpin lower section 1-2, and a lower adjustment gasket 14 is installed between the bottom of the cavity of the support base 12 and the ball bowl 15 assembled therewith; a steel ball 13 is assembled between the two ball bowls 15.

[0025] See also Figures 1 to 12 The present invention also provides a maintenance-free structure assembly method for the axial clearance of the steering kingpin of an automobile, which is special in that: the axial assembly clearance of the steel ball is reserved in the assembly structure of the lower section of the kingpin, and the disc spring is pre-compressed in the assembly structure of the upper section of the kingpin, so as to realize the automatic adjustment of the axial clearance of the steering kingpin during the loading and operation of the vehicle. The following is a specific embodiment of a steering drive axle with a full load mass of 8 tons to illustrate its operation steps: a. According to the stress conditions of the vehicle, the maximum load that each steering kingpin (single-sided steel ball) bears under the maximum load state of the steering drive axle is calculated to be 3700 kg (36260N), and then according to the set disc spring preload coefficient C (preload coefficient C = F disc spring preload force / N single-sided steel ball, according to relevant design requirements, the preload coefficient C is generally between 0.4-0.5, and the preload coefficient C in this embodiment is 0.443), the preload force of the disc spring is calculated to be 36260×0.443=16062N, and two parallel superimposed disc springs 10 are selected, preferably with a model specification of 30.5×70×2.5mm, a free state height of 7.4mm, a flattened height of 5mm, and a corresponding maximum stroke of 2.4mm. According to the preload force requirements of the disc spring, the pre-compression amount s of the disc spring 10 is set to 75% of the maximum stroke, that is, the disc spring 10 and the compression amount s=1.8 mm; b. According to the vehicle load and the size chain relationship of each matching component, set the reserved gap x1 between the steel ball 13 and the bottom ball bowl of the kingpin lower section 1-2 to 0-0.3mm, and then calculate the theoretical thickness b1 of the lower adjustment gasket 14; c. Select a lower adjustment gasket 14 with a thickness value consistent with the theoretical thickness, place it at the bottom of the cavity of the support base 12, and press-fit a ball bowl 15 with an opening upward into the cavity of the support base 12 and the bottom center blind hole of the kingpin lower section 1-2, place a steel ball 13 in the ball bowl 15, screw-fit the pressure cover 8 and press-fit a ball bowl 15 with an opening downward into the center blind holes on the top surface of the kingpin upper section 1-1 and the bottom surface of the kingpin lower section 1-2 on the steering fork 1, and then assemble the steering fork 1 with the steering knuckle 2; d. Place the inner spline seat 7 in the kingpin upper section assembly structure above the first assembly hole 2-1 of the steering knuckle 2, place the outer spline slider 9 on the pressure cover 8 and assemble it with the inner spline seat 7, place the parallel overlapping combined disc spring 10 on the pressure cover 8 in a free state, press the upper cover 8 on the disc spring 10, place the two parallel overlapping combined disc springs 10 selected in step a between the bottom surface of the inner spline seat 7 and the upper end surface of the steering knuckle 2, respectively measure the distance h1 between the upper end surface of the inner spline seat 7 and the upper end surface of the steering knuckle 2, and the distance h2 between the bottom surface of the upper cover 11 and the upper end surface of the steering knuckle 2, calculate the difference Δ1 between h2 and h1, and determine the thickness dimension w1 of the upper adjustment gasket 6 as the difference between Δ1 and the pre-compression amount s of the disc spring 10, that is, w1=Δ1-s, and then connect the upper cover 8, the inner spline seat 7, the upper adjustment gasket 6 and the steering knuckle 2 through six groups of bolts 4 arranged along the circumference of the upper cover 11; e. Adjustment of the axial clearance of the kingpin lower section. Use a detection tool to measure the actual clearance x2 between the steel ball 13 and the bottom ball bowl of the kingpin lower section 1-2, calculate the difference Δ2 between the measured actual clearance x2 and the set reserved clearance x1, that is, Δ2= x2-x1, and then calculate the actual thickness b2 of the lower adjustment gasket 14. The actual thickness dimension b2 of the lower adjustment gasket 14 is the difference between Δ2 and the theoretical thickness b1 of the lower adjustment gasket, that is, b2=Δ2- b1; f. Disassemble the steering fork 1 and the steering knuckle 2, and push out the ball bowl 15 pressed into the central blind hole 1-3 of the kingpin lower section 1-2 of the steering fork 1 through the adjustment process hole 12-1 on the bottom surface of the support base 12, and replace the adjustment gasket 14 with a thickness consistent with the calculated actual thickness b2, and repeat steps c and d to complete the assembly process of the maintenance-free structure of the automobile steering kingpin axial clearance.

[0026] In a specific embodiment of a steering drive axle with a full load mass of 8 tons, according to relevant design requirements, the preload coefficient C of the disc spring (=F disc spring preload / N single-sided steel ball) is between 0.4-0.5; the total preload safety factor of the upper cover connecting bolts: B1=Pmax / F disc spring preload, B2=Pmax / F disc spring max; the value is between 5-5.5. In this embodiment, the disc spring 10 is a combination of two parallel overlapping disc springs 10, with a model specification of 30.5×70×2.5mm, a free state height of 7.4mm, a flattened height of 5mm, and a corresponding maximum stroke of 2.4mm. The pre-compression amount s of the disc spring 10 is set to 75% of the maximum stroke, that is, the disc spring 10 and the compression amount s=1.8 mm, thus forming the initial preload force. According to the force analysis calculation, F disc spring preload force = 8031 ​​× 2 = 16062N; the bearing capacity of the steel ball at the lower part of each steering kingpin is N single-side steel ball, N single-side steel ball = 36260N; then the disc spring preload coefficient C = F disc spring preload force / N single-side steel ball = 16062 / 36260 = 0.443; in this embodiment, six M8 × 40-10.9 grade connecting bolts are selected and tightened step by step. The preload force of each bolt is P0=M×1000 / (dK); wherein M is the tightening torque, which is 35Nm; d is the thread diameter of 8mm; K is the tightening torque coefficient, which is generally 0.1-0.3, and K in this embodiment is 0.3; then P0=14583N; total preload force Pmax=6P0=87498N; F disc spring preload force=16062N; F disc spring max=18720N; safety factor: B1=Pmax / F disc spring preload force=5.45; B2=Pmax / F disc spring max=4.674; after comparison, the preload coefficient C of the disc spring and the total preload safety factor B of the upper cover bolts in this embodiment meet the design requirements.

Claims

1. A maintenance-free structure for the axial clearance of a steering kingpin of an automobile, wherein a steering knuckle (2) and a steering fork (1) in an automobile steering system are assembled together by cooperating with an upper assembly structure and a lower assembly structure of the steering kingpin of the automobile, and a central blind hole (1-3) is provided at the top of the upper kingpin section (1-1) and the bottom of the lower kingpin section (1-2) of the steering fork (1); the characteristics are as follows: In the upper section assembly structure, the kingpin upper section (1-1) is assembled with a first assembly hole (2-1) on the steering knuckle (2), and a bearing (5) is assembled between the kingpin upper section (1-1) and the first assembly hole (2-1). An inner spline seat (7) and an upper cover (11) are arranged above the first assembly hole (2-1) of the steering knuckle (2). The central blind hole (1-3) at the top of the kingpin upper section (1-1) is a threaded hole. A pressure cover (8) is screwed into the threaded hole to form a cavity between the pressure cover (8) and the upper cover (11). An outer spline slider (9) is arranged on the pressure cover (8). The outer spline slider (9) cooperates with the inner spline seat (7) to slide up and down in the cavity between the pressure cover (8) and the upper cover (11). A disc spring (10) is assembled between the outer spline slider (9) and the pressure cover (8); In the lower section assembly structure, the kingpin lower section (1-2) is assembled with a second assembly hole (2-2) on the steering knuckle (2), and a bearing (5) is assembled between the kingpin lower section (1-2) and the second assembly hole (2-2); the second assembly hole (2-2) is a stepped hole; a support base (12) is embedded in the bottom of the second assembly hole (2-2); the support base (12) is provided with a cavity with an upper opening; two ball bowls (15) are relatively pressed into the cavity of the support base (12) and the bottom center blind hole of the kingpin lower section (1-2); and a steel ball (13) is assembled between the two ball bowls (15).

2. The maintenance-free structure for the axial clearance of the steering kingpin of an automobile according to claim 1, characterized in that: In the upper section assembly structure, an adjustment gasket (6) is installed between the inner spline seat (7) and the upper end surface of the steering knuckle (2).

3. The maintenance-free structure for the axial clearance of the steering kingpin of an automobile according to claim 2, characterized in that: In the lower section assembly structure, a lower adjustment gasket (14) is installed between the bottom of the cavity of the support base (12) and the ball bowl (15) assembled therewith.

4. The maintenance-free structure for the axial clearance of the steering kingpin of an automobile according to claim 3 is characterized in that: An adjustment process hole (12-1) is provided on the bottom surface of the support base (12).

5. The maintenance-free structure for the axial clearance of the automotive steering kingpin according to any one of claims 1 to 4, characterized in that: The disc springs (10) assembled between the external spline slider (9) and the pressure cover (8) are at least two in number and are assembled in a parallel overlapping manner in the same direction.

6. The maintenance-free structure for the axial clearance of the steering kingpin of an automobile according to claim 5, characterized in that: The bearings (5) mounted between the kingpin upper section (1-1) and the first assembly hole (2-1) and between the kingpin lower section (1-2) and the second assembly hole (2-2) are both needle roller bearings.

7. The maintenance-free structure for the axial clearance of the steering kingpin of an automobile according to claim 5, characterized in that: The upper cover (11) and the inner spline seat (7) are fixedly assembled with the steering knuckle (2) via a group of bolts (4) evenly arranged in the circumferential direction.

8. A maintenance-free structure assembly method for the axial clearance of a steering kingpin of an automobile, characterized in that: The axial assembly clearance of the steel ball is reserved in the lower assembly structure of the kingpin, and the disc spring is pre-compressed in the upper assembly structure of the kingpin to realize the automatic adjustment of the axial clearance of the steering kingpin during the loading and operation of the vehicle. The specific operation steps are as follows: a. Calculate the maximum load that the steering kingpin bears when the vehicle is fully loaded based on the force applied to the steering kingpin, and then set the preload force and precompression amount s of the disc spring (10) in combination with the characteristics of the disc spring (10); b. According to the load condition of the whole vehicle and the assembly dimension chain relationship between the matching parts of the steering system, set the reserved gap x1 between the steel ball (13) and the bottom ball bowl of the kingpin lower section (1-2), and calculate the theoretical thickness b1 of the lower adjustment gasket (14); c. Select a lower adjustment gasket (14) whose thickness value is consistent with the theoretical thickness, place it at the bottom of the cavity of the support base (12), and press-fit a ball bowl (15) with an opening upward into the cavity of the support base (12) and the bottom center blind hole of the kingpin lower section (1-2), place a steel ball (13) in the ball bowl (15), screw or press-fit a gland (8) and a ball bowl (15) with an opening downward into the center blind holes of the top surface of the kingpin upper section (1-1) and the bottom surface of the kingpin lower section (1-2) on the steering fork (1), respectively, and then assemble the steering fork (1) and the steering knuckle (2); d. Place the inner spline seat (7) in the upper assembly structure of the kingpin above the first assembly hole (2-1) of the steering knuckle (2), place the outer spline slider (9) on the pressure cover (8) and assemble it with the inner spline seat (7), place the parallel superimposed combined disc spring (10) on the pressure cover (8) in a free state, press the upper cover (11) on the disc spring (10), select an upper adjustment gasket (6) of appropriate thickness according to the pre-compression amount s of the disc spring (10), place it between the bottom surface of the inner spline seat (7) and the upper end surface of the steering knuckle (2), and then fix the upper cover (11), the inner spline seat (7), the upper adjustment gasket (6) and the steering knuckle (2) with bolts (4); e. Adjusting the axial clearance of the kingpin lower section: using a detection tool to measure the actual clearance x2 between the steel ball (13) and the bottom ball bowl of the kingpin lower section (1-2), and calculating the difference Δ2 between the measured actual clearance x2 and the set reserved clearance x1, that is, Δ2 = x2-x1, and then calculating the actual thickness b2 of the lower adjustment gasket (14) based on the Δ2 value; f. Disassemble the steering fork (1) and the steering knuckle (2), replace the adjustment gasket (14) with a thickness dimension consistent with the calculated actual thickness b2, repeat steps c and d, and complete the assembly process of the maintenance-free structure of the steering kingpin axial clearance of the automobile.

9. The method for assembling the maintenance-free structure of the steering kingpin axial clearance of an automobile according to claim 8, characterized in that: In step d, the thickness dimension of the upper adjustment gasket (6) is determined by the following method: the distance h1 between the upper end surface of the inner spline seat (7) and the upper end surface of the steering knuckle (2) and the distance h2 between the bottom surface of the upper cover (11) and the upper end surface of the steering knuckle (2) are measured respectively, and the difference Δ1 between h2 and h1 is calculated. Based on this, the thickness dimension w1 of the upper adjustment gasket (6) is determined to be the difference between Δ1 and the pre-compression amount s of the disc spring (10), that is, w1=Δ1-s.

10. The method for assembling the maintenance-free structure of the steering kingpin axial clearance of an automobile according to claim 8, characterized in that: In the step e, the actual thickness dimension b2 of the lower adjustment gasket (14) is the difference between Δ2 and the theoretical thickness b1 of the lower adjustment gasket, that is, b2=Δ2- b1.

Images