A leaf spring pad device incorporating a positioning pin

Abstract

The utility model relates to a spring washer device of integrated positioning pin, including washer body (1), its characterized in that: washer body (1) adopts nylon PA6 -MC material integrated forming, the geometric center of washer body (1) is pre -buried with metal positioning axle sleeve (3), the upper end of this positioning axle sleeve (3) is extended and is formed with the positioning hole (31) for connecting the leaf spring, the lower end is extended and is formed with the positioning pin (32) for connecting the axle, washer body (1) four corners respectively pre -buried with metal support column (2), and the axial both ends of each metal support column (2) are flush with washer body surface to provide rigid support. The utility model discloses a novel spring washer with the functions of light weight, high corrosion resistance and integrated positioning, which breaks through the systemic limitations of traditional metal materials and split structure.

Description

Technical Field

[0001] This utility model belongs to the technical field of vehicle suspension systems, and particularly relates to a leaf spring pad device with integrated positioning pin. Background Technology

[0002] As a key adjustment component of the suspension system, the leaf spring pad is mainly used to control the vehicle's axle load, height, attitude angle, and caster angle parameters. Currently, the industry generally uses ductile iron QT450-10 material to manufacture the pad body; please refer to [link / reference]. Figure 7 Its typical structure is a planar plate-like column with a weight-reducing groove in the middle. However, this traditional solution has significant drawbacks:

[0003] Lightweight bottleneck: Ductile iron has a density as high as 7.3 g / cm³. Even with the design of weight reduction grooves, the weight of a single part is still 1.2-1.5kg, resulting in excessive weight of the suspension system, which directly affects the vehicle's fuel economy.

[0004] Insufficient corrosion resistance: In harsh working conditions such as mines and salt spray, cast iron surfaces are prone to oxidation and rust, requiring frequent spraying of anti-rust coatings for maintenance, which increases the total life cycle cost;

[0005] Low assembly efficiency: The pad body requires additional machining of positioning holes, and assembly relies on independent pins to connect it to the axle. The split structure results in a pin hole alignment error of ≥0.5mm, forcing the production line to repeatedly adjust the positioning, increasing the assembly time of a single part by more than 30%, and severely restricting the production cycle.

[0006] Existing attempts to further enlarge the weight-reducing groove to reduce weight will weaken the structural strength and fail to meet the requirements.

[0007] While replacing cast iron with stainless steel improves corrosion resistance, it also significantly increases material costs and reduces weight by less than 15%. Therefore, there is an urgent need for a new type of leaf spring pad that combines lightweight, high corrosion resistance, and integrated positioning functions to overcome the systemic limitations of traditional metal materials and split structures. Utility Model Content

[0008] To address the problems existing in the prior art, this utility model provides a leaf spring pad device with integrated positioning pins.

[0009] This utility model is implemented as follows: a leaf spring pad device with integrated positioning pin, including a pad body, characterized in that: the pad body is integrally molded from nylon PA6-MC material;

[0010] A metal positioning bushing is pre-embedded at the geometric center of the pad body. The upper end of the positioning bushing extends to form a positioning hole for connecting the leaf spring, and the lower end extends to form a positioning pin for connecting the axle. Metal support columns are pre-embedded at the four corners of the pad body, and the axial ends of each metal support column are exposed on the surface of the pad body to provide rigid support.

[0011] The surface of the pad body on the locating pin side forms a 2-degree angle with the horizontal plane.

[0012] More preferably, the outer surfaces of the metal positioning bushing and the metal support column are provided with knurled patterns, which are embedded in the nylon material to enhance the bonding strength.

[0013] More preferably, the positioning hole of the positioning bushing is a blind hole structure, and the positioning pin is a solid cylinder, both of which are eccentrically formed on the positioning bushing.

[0014] More preferably, the number of metal support columns is four, symmetrically distributed at the four vertices of a rectangle centered on the positioning bushing.

[0015] More preferably, the nylon PA6-MC material has a flexural strength ≥65 MPa, a flexural modulus ≥1850 MPa, a density range of 1.13-1.16 g / cm³, a tensile strength ≥60 MPa, an elongation at break ≥40%, a notched cantilever beam impact strength ≥7.0 KJ / m², a dimensional change rate ≤8% after thermal cycling test, and a Rockwell hardness ≥115 HRR.

[0016] More preferably, the metal positioning bushing and / or metal support column are made of 45# steel.

[0017] More preferably, the diameter of the locating pin and the clearance fit tolerance of the axle mounting hole are H7 / g6.

[0018] More preferably, the outer edge of the positioning hole is provided with a tapered guide surface;

[0019] The geometric dimensions of the pad body 1 are: length 160mm, width 89mm, and the minimum geometric center height of the pad body after removing the positioning pin is 20mm.

[0020] The advantages and technical effects of this utility model are as follows: The integrated positioning pin leaf spring washer device of this utility model has excellent overall technical effect, and achieves breakthrough improvement in several key performance dimensions:

[0021] Significant weight reduction and cost optimization: Replacing traditional ductile iron (QT450-10) with PA6-MC nylon material reduces part weight by 70%. Procurement costs are reduced by 5%, while the overall vehicle load is reduced, improving fuel economy.

[0022] Improved corrosion resistance and lifespan: PA6-MC material is naturally corrosion resistant, completely solving the problem of cast iron rust, significantly reducing maintenance frequency and costs, and extending service life.

[0023] Assembly efficiency and precision innovation: The integrated locating pin design eliminates the need for separate pin structures, thus eliminating pin hole alignment errors. Assembly steps are simplified, improving workshop assembly efficiency and production line cycle time. The locating bushing simultaneously connects the leaf spring (locating hole) and the axle (locating pin), ensuring high-precision positioning.

[0024] Strengthening structural strength and reliability: Pre-embedded metal support columns + knurling process: enhances the local strength of the nylon body and ensures the reliability of the component through friction locking.

[0025] High stress safety margin: The overall stress is ≤150MPa, which is far lower than the yield strength of PA6-MC material (310MPa), making it safe and reliable.

[0026] Enhanced NVH performance and comfort: Nylon materials possess high damping coefficients and low modulus of elasticity, effectively absorbing the impact energy and mechanical vibrations generated by vehicle bumps. This significantly reduces noise, vibration, and shock (NVH), improving ride comfort. Attached Figure Description

[0027] Figure 1 This is a top view of the present invention;

[0028] Figure 2 yes Figure 1 Sectional view of AA;

[0029] Figure 3 and Figure 4 This is a three-dimensional structural diagram of the present invention;

[0030] Figure 5 This is a stress analysis diagram of this utility model;

[0031] Figure 6 This is a schematic diagram of the assembly structure of this utility model;

[0032] Figure 7 This is a schematic diagram of the existing technology structure.

[0033] In the diagram: 1. Pad body; 2. Metal support column; 3. Metal positioning bushing; 31. Positioning hole; 32. Positioning pin. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this utility model.

[0035] Please see Figures 1 to 6 A leaf spring pad device with integrated positioning pin includes a pad body 1, wherein the pad body 1 is integrally molded from nylon PA6-MC material;

[0036] A metal positioning bushing 3 is pre-embedded in the geometric center of the pad body 1. The upper end of the positioning bushing 3 extends to form a positioning hole 31 for connecting the leaf spring, and the lower end extends to form a positioning pin 32 for connecting the axle.

[0037] Metal support columns 2 are pre-embedded at the four corners of the pad body 1. The axial ends of each metal support column 2 are flush with the surface of the pad body to provide rigid support. Traditional ductile iron pads are heavy, costly, and have low assembly efficiency. This solution uses nylon PA6-MC to replace ductile iron, achieving a 70% weight reduction and lowering costs. Pre-embedded metal positioning bushings integrate positioning holes and positioning pins, eliminating assembly errors of separate pins and improving assembly efficiency. The pre-embedded metal support columns at the four corners, with their ends exposed, compensate for the insufficient strength of nylon, ensuring structural reliability and overcoming the limitations of traditional metal materials and separate structures.

[0038] The surface of the pad body 1 on the side of the locating pin 32 forms a 2-degree angle α with the horizontal plane, and the side of the locating hole is a planar structure. The purpose is to provide the vehicle with a 5-degree kingpin caster angle (the caster angle without the pad is 3 degrees), ensuring the vehicle's straight-line driving stability and automatic steering return function.

[0039] Preferably, the geometric dimensions of the pad body 1 are 160mm in length (matching the straight section of the leaf spring), 89mm in width (matching the width of the leaf spring), and a minimum center height of 20mm. The height of the pad can be adjusted according to the needs of vehicle posture and axle load adjustment.

[0040] In a further preferred embodiment, the outer surfaces of the metal positioning bushing 3 and the metal support column 2 are provided with knurled patterns; traditional pads are prone to corrosion under harsh working conditions and require frequent maintenance. This solution features knurled patterns on the outer surfaces of the metal positioning bushing and support column, with nylon embedded within, enhancing the bonding strength between the metal and nylon, overcoming the problem of easy peeling at the interface, improving overall durability, reducing maintenance costs due to corrosion, and extending service life.

[0041] In a further preferred embodiment, the positioning hole 31 of the positioning bushing 3 is a blind hole structure, and the positioning pin 32 is a solid cylinder, both eccentrically formed on the positioning bushing 3. Traditional split-type inclined pads and pins are designed as separate structures, resulting in large pin hole alignment errors and low assembly efficiency. Furthermore, due to the angled assembly of the inclined pad, the axis of the U-bolt is not completely parallel and coincident with the axis of the U-bolt mounting hole on the axle, leading to easy loosening of the U-bolt. In this application, the positioning hole of the positioning bushing is a blind hole, and the positioning pin is a solid cylinder, both eccentrically formed as a single unit. This eliminates assembly errors associated with split pins, improves assembly efficiency, and ensures that the axis of the U-bolt is parallel and coincident with the axis of the U-bolt mounting hole on the axle, effectively preventing the loosening of the U-bolt and its matching nut.

[0042] In a further preferred embodiment, the number of metal support columns 2 is four, symmetrically distributed at the four vertices of a rectangle centered on the positioning bushing 3. This arrangement of four metal support columns symmetrically distributed at the four vertices of a rectangle centered on the positioning bushing matches the stress characteristics of the axle mounting surface, resulting in a more uniform load distribution, preventing localized stress concentration, and improving the structural strength of the device.

[0043] Further preferably, the nylon PA6-MC material has a flexural strength ≥65 MPa, a flexural modulus ≥1850 MPa, a density range of (1.13-1.16) g / cm³, a tensile strength ≥60 MPa, an elongation at break ≥40%, a cantilever beam notched impact strength ≥7.0 KJ / m² without fracture, no cracking or damage after heat aging test, a dimensional change rate ≤8% after thermal cycling test, no cracking, stickiness, swelling, or other phenomena under a 10x magnifying glass after hot air aging test, a Rockwell hardness ≥115 HRR, and the sample must not crack or break under ultimate failure, and the dimensional change rate ≤1%.

[0044] The specific experiment is as follows: The geometric dimensions of the pad body 1 are as follows: length 160mm, width 89mm, and the minimum height of the geometric center of the pad body after removing the positioning pin is 20mm.

[0045] Five samples were selected for tests including bending strength, bending modulus, density, tensile strength, elongation at break, cantilever beam notched impact strength, heat aging resistance, thermal cycling resistance, hot air accelerated aging test, Rockwell hardness, and ultimate failure test. The experimental conditions and results are as follows.

[0046] Experimental conditions:

[0047]

[0048] The experimental results are as follows:

[0049]

[0050] While pre-embedding the metal support column, the positioning pin is integrated with the nylon body, and the overall stress of the components is only below 150MPa. Please refer to [link / reference]. Figure 5 With a yield strength far below the 310MPa of QT450-10 material, it maintains structural strength and hardness of parts while reducing weight. It also features a high damping coefficient and a low elastic modulus, enabling it to effectively absorb impact energy and mechanical vibration. This significantly reduces noise, vibration, and impact caused by vehicle bumps, improving overall vehicle NVH and comfort, extending service life, and reducing costs. Its low density allows for a 70% weight reduction while maintaining sufficient tensile and flexural strength to meet load-bearing requirements. Furthermore, it possesses excellent aging and corrosion resistance, balancing lightweight design, mechanical properties, corrosion resistance, and weather resistance. This effectively improves vehicle fuel economy, component corrosion resistance, and usage frequency.

[0051] Further preferably, the metal positioning bushing 3 and / or the metal support column 2 are made of 45# steel. Replacing cast iron with stainless steel significantly increases costs and results in low weight reduction. This solution uses 45# steel for the metal positioning bushing and / or support column, combining high strength with low cost, avoiding the cost spike problem associated with stainless steel solutions, and controlling costs while ensuring performance.

[0052] In a further preferred embodiment, the diameter of the locating pin 32 and the clearance fit tolerance of the axle mounting hole are H7 / g6. This solution, with a locating pin diameter and axle mounting hole clearance fit tolerance of H7 / g6, solves the pin hole alignment error problem, enabling direct assembly without adjustment, improving assembly efficiency, and increasing production cycle time.

[0053] More preferably, the outer edge of the positioning hole 31 is provided with a tapered guide surface 33. The tapered guide surface, through its inclined geometry, provides guidance for the positioning pin during assembly. When there is a slight deviation between the positioning pin and the positioning hole, the tapered surface can guide the pin to automatically align with the hole, reducing the number of manual adjustments or repeated attempts.

[0054] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A leaf spring washer device with integrated positioning pin, comprising a washer body (1), characterized in that: The pad body (1) is integrally molded from nylon PA6-MC material; The geometric center of the pad body (1) is pre-embedded with a metal positioning bushing (3), the upper end of which extends to form a positioning hole (31) for connecting the leaf spring, and the lower end extends to form a positioning pin (32) for connecting the axle. Metal support columns (2) are pre-embedded at the four corners of the pad body (1), and the two ends of each metal support column (2) are flush with the surface of the pad body to provide rigid support.

2. The leaf spring washer device according to claim 1, characterized in that: The surface of the pad body (1) on the side of the positioning pin (32) forms an angle of 2 degrees with the horizontal plane; the side of the positioning hole (31) is a planar structure.

3. The leaf spring washer device according to claim 1, characterized in that: The outer surfaces of the metal positioning bushing (3) and the metal support column (2) are provided with knurled patterns, which are embedded in the nylon material to enhance the bonding strength.

4. The leaf spring washer device according to any one of claims 1 to 3, characterized in that: The positioning hole (31) of the positioning bushing (3) is a blind hole structure, and the positioning pin (32) is a solid cylinder. The two are eccentrically formed on the positioning bushing (3).

5. The leaf spring washer device according to claim 1, characterized in that: The number of metal support columns (2) is 4, symmetrically distributed at the four vertices of a rectangle centered on the positioning bushing (3).

6. The leaf spring washer device according to claim 1, characterized in that: The nylon PA6-MC material has a flexural strength ≥65 MPa, a flexural modulus ≥1850 MPa, a density range of 1.13-1.16 g / cm³, a tensile strength ≥60 MPa, an elongation at break ≥40%, a notched cantilever beam impact strength ≥7.0 KJ / m², a dimensional change rate ≤8% after thermal cycling test, and a Rockwell hardness ≥115 HRR.

7. The leaf spring washer device according to claim 1, characterized in that: The metal positioning bushing (3) and / or metal support column (2) are made of 45# steel.

8. The leaf spring washer device according to claim 1, characterized in that: The diameter of the positioning pin (32) and the clearance fit tolerance of the axle mounting hole are H7 / g6.

9. The leaf spring washer device according to claim 1, characterized in that: The outer edge of the positioning hole (31) is provided with a tapered guide surface (33).

10. The leaf spring washer device according to claim 1, characterized in that: The geometric dimensions of the pad body (1) are: length 160mm, width 89mm, and the minimum height of the geometric center of the pad body after removing the positioning pin is 20mm.

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