A tooling fixture positioning spring pin

Abstract

This utility model discloses a tooling fixture positioning spring pin with a drag-reducing groove structure, including a spring pin body and a spring assembly. The spring pin body has a tapered surface, and the spring assembly applies axial elastic pressure to the spring pin body. A drag-reducing groove group is provided in the axial center of the tapered surface. The drag-reducing groove group includes three rectangular drag-reducing grooves, which are symmetrically distributed 120° equally in the circumferential direction. The groove width is 2.0±0.1mm, and the groove depth is 0.8±0.1mm. This utility model replaces traditional linear contact with three-point intermittent contact, solving the problems of unstable contact, stress concentration, and insufficient accuracy in the prior art. It significantly improves positioning accuracy, contact pressure uniformity, and compatibility, and extends the service life of the spring pin. It is suitable for tooling fixture positioning scenarios for workpieces such as die-cast parts.

Description

Technical Field

[0001] This utility model relates to the field of tooling and fixture technology, and in particular to a tooling and fixture positioning spring pin. Background Technology

[0002] In the field of machining, especially in die casting, the positioning accuracy of tooling fixtures directly determines the final machining quality of the workpiece. Currently, die casting tooling fixtures generally adopt the linear positioning method of spring pin tapered surface. Its core structure includes spring pin body and spring: the tapered surface of the spring pin body abuts against the edge of the workpiece's circular hole through spring pressure, forming a continuous annular line contact (full circumference contact), and constraining the workpiece's degree of freedom through two-point symmetrical contact.

[0003] However, this traditional structure has the following significant drawbacks: Poor contact stability: Linear contact is highly sensitive to the flatness of the workpiece hole edge. When the roughness of the workpiece hole edge is high, the tiny protrusions or depressions on the hole edge will disrupt the balance of contact forces, causing the spring pin to lose its support for the workpiece, which can easily lead to workpiece tilting and seriously affect the consistency of subsequent machining datum.

[0004] Significant stress concentration: The contact pressure is concentrated on a single ring-shaped contact line. Excessive local pressure can cause micro-deformation of the workpiece. For die-cast parts with high precision requirements, this deformation may directly lead to the scrapping of the workpiece and increase production costs. At the same time, long-term stress concentration will also accelerate the wear of the spring needle and shorten its service life.

[0005] Insufficient positioning accuracy: In actual measurements at machining centers, when using traditional spring pin positioning, the flatness error of the workpiece machining surface fluctuates greatly, often exceeding the reference requirements for precision machining, and failing to meet the needs of high-precision machining. Utility Model Content

[0006] The purpose of this utility model is to provide a tooling fixture positioning spring pin with a drag-reducing groove structure, which solves the problems of unstable contact, stress concentration and insufficient accuracy in the prior art by optimizing the contact form and structural design.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A tooling fixture positioning spring pin with a drag-reducing groove structure includes a spring pin body and a spring assembly. The spring pin body has a tapered surface. The spring assembly is used to apply axial elastic pressure to the spring pin body. A drag-reducing groove group is provided in the axial middle of the tapered surface. The drag-reducing groove group includes three rectangular drag-reducing grooves. The three drag-reducing grooves are symmetrically distributed in a 120° even distribution in the circumference. The groove width of the drag-reducing groove is 2.0±0.1mm, and the groove depth is 0.8±0.1mm. The sidewall of the drag-reducing groove transitions perpendicularly to the tapered surface at 90°. The raised tapered surface between two adjacent drag-reducing grooves forms an independent contact area.

[0008] Preferably, the drag-reducing groove has a gradient depth design, and the groove depth ranges from 0.5 to 1.0 mm.

[0009] Preferably, the width deviation of the drag-reducing groove is controlled within ±0.05mm.

[0010] Preferably, the surface roughness Ra of the contact area is ≤1.6μm.

[0011] Preferably, the main body of the spring needle is made of alloy structural steel.

[0012] Preferably, the spring stiffness of the spring assembly is 5-8 N / mm.

[0013] The beneficial effects of this utility model are: Three-point intermittent contact reduces the sensitivity to the flatness of the workpiece hole edge, effectively controls flatness error, and meets the requirements of precision machining.

[0014] The pressure is distributed across three contact areas, avoiding stress concentration, reducing micro-deformation of the workpiece, and lowering the scrap rate.

[0015] It can be adapted to workpieces with higher hole edge roughness, reducing the requirements for workpiece pretreatment and expanding the application range.

[0016] The contact pressure distribution is more uniform, reducing local wear on the spring pin, extending its service life, and reducing maintenance costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a positioning spring pin for a tooling fixture proposed in this utility model; Figure 2 for Figure 1 A schematic diagram of the structure viewed from below; Figure 3 for Figure 1 A schematic diagram of the vertical cross-section structure.

[0018] In the diagram: 1. Spring pin body, 2. Spring assembly, 3. Tapered surface, 4. Drag reduction groove. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0020] Reference Figure 1-3 A tooling fixture positioning spring pin with a drag-reducing groove structure includes a spring pin body 1 and a spring assembly 2. The spring pin body 1 has a tapered surface 3. The spring assembly 2 is used to apply axial elastic pressure to the spring pin body 1. A drag-reducing groove group is provided in the axial middle of the tapered surface 3. The drag-reducing groove group includes three rectangular drag-reducing grooves 4. The three drag-reducing grooves 4 are symmetrically distributed in a 120° circumferential direction. The groove width of the drag-reducing groove 4 is 2.0±0.1mm, the groove depth of the drag-reducing groove 4 is 0.8±0.1mm, the sidewall of the drag-reducing groove 4 transitions perpendicularly to the tapered surface 3 at 90°, and the raised tapered surface 3 between two adjacent drag-reducing grooves 4 forms an independent contact area.

[0021] The drag-reducing groove 4 has a gradient depth design, with a groove depth range of 0.5-1.0 mm.

[0022] The width deviation of the drag-reducing groove 4 is controlled within ±0.05mm.

[0023] The surface roughness Ra of the contact area is ≤1.6μm.

[0024] The main body of the spring needle 1 is made of alloy structural steel.

[0025] The spring stiffness of spring assembly 2 is 5-8 N / mm.

[0026] Machining of the spring needle body 1: Using alloy structural steel, the initial shape of the spring needle body 1 with a tapered surface 3 is machined. Then, three rectangular drag-reducing grooves 4 are machined in the axial center of the tapered surface 3 using CNC milling equipment, ensuring that the three grooves 4 are symmetrically distributed 120° circumferentially. The dimensions of the drag-reducing grooves 4 are controlled as follows: groove width 2.0±0.1mm (can be controlled within ±0.05mm for high precision requirements), groove depth 0.8±0.1mm (depth can be designed in gradients of 0.5-1.0mm), and the groove sidewalls transition perpendicularly to the tapered surface 3 at a 90° angle to avoid stress concentration. Finally, the raised tapered surface 3 (contact area) between the grooves is ground to achieve a surface roughness Ra≤1.6μm, ensuring contact stability.

[0027] Spring assembly 2 assembly: Select spring assembly 2 with spring stiffness of 5-8N / mm and assemble it with the processed spring needle body 1 to ensure that the spring can provide stable axial elastic pressure to the spring needle body 1, so that the spring needle can reliably abut against the edge of the workpiece round hole when working.

[0028] To verify the technical effect of this utility model, a positioning test was conducted on ADC12 aluminum alloy die-cast parts (batch size 500 pieces) on the XYZ-2000 machining center. The test results are compared with the prior art in the following table:

[0029] Test results show that the positioning spring pin of the tooling fixture with drag-reducing groove 4 of this utility model, through three-point intermittent contact and the drag-reducing groove 4 design, significantly improves positioning accuracy, contact stability and compatibility, and extends the service life of the spring pin, fully achieving the preset technical objectives. Working principle of this utility model: During workpiece installation, the edge of the workpiece's circular hole only contacts the contact area formed by the three raised tapered surfaces 3 on the spring needle body 1. The spring assembly 2 pushes the spring needle body 1 to form a three-point support. The drag-reducing groove group eliminates the continuity of the contact surface, making the contact pressure evenly distributed in three discrete contact areas. Stable positioning is achieved by constraining the workpiece's degrees of freedom through three-point discontinuous contact.

[0030] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A tooling fixture positioning spring pin, comprising a spring pin body (1) and a spring assembly (2), wherein the spring pin body (1) has a tapered surface (3), and the spring assembly (2) is used to apply axial elastic pressure to the spring pin body (1), characterized in that: The tapered surface (3) has a drag-reducing groove group in the axial middle part. The drag-reducing groove group includes three rectangular drag-reducing grooves (4). The three drag-reducing grooves (4) are symmetrically distributed in a 120° circumferential direction. The groove width of the drag-reducing groove (4) is 2.0±0.1mm, and the groove depth of the drag-reducing groove (4) is 0.8±0.1mm. The sidewall of the drag-reducing groove (4) is perpendicular to the tapered surface (3) at 90°. The raised tapered surface (3) between two adjacent drag-reducing grooves (4) forms an independent contact area.

2. The tooling fixture positioning spring pin according to claim 1, characterized in that: The drag-reducing groove (4) has a gradient depth design, and the groove depth range of the drag-reducing groove (4) is 0.5-1.0mm.

3. The tooling fixture positioning spring pin according to claim 1, characterized in that: The groove width deviation of the drag-reducing groove (4) is controlled within ±0.05mm.

4. The tooling fixture positioning spring pin according to claim 1, characterized in that: The surface roughness Ra of the contact area is ≤1.6μm.

5. A tooling fixture positioning spring pin according to claim 1, characterized in that: The main body of the spring needle (1) is made of alloy structural steel.

6. A tooling fixture positioning spring pin according to claim 1, characterized in that: The spring stiffness of the spring assembly (2) is 5-8 N / mm.

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