A floating self-centering type clamp structure for improving press fitting precision of a lifting bushing

Abstract

The utility model provides a kind of floating self-centering type fixture structure for improving bushing press fitting accuracy, including base assembly and upper press head assembly, the base assembly includes the press fitting base for supporting product, the press fitting base is internally provided with the positioning mandrel that can float up and down, the top end of the positioning mandrel can be installed bushing after being passed out the inner hole of product;The upper press head assembly includes upper press head, the upper press head is internally provided with the centre of the top that can float up and down, the tip of the centre of the top projects upper press head setting and can be with the axial center of positioning mandrel cooperation centring, the centre of the top can be driven down after moving down positioning mandrel and bushing is pressed into the inner hole of product.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical manufacturing technology, specifically relating to a floating self-centering fixture structure for improving the accuracy of bushing pressing. Background Technology

[0002] In precision machinery manufacturing (such as automotive transmissions and industrial robot joints), bushing press fitting is a key process to ensure the fitting accuracy of transmission components. The structure of a typical bushing press fitting fixture is shown below. Figure 2 Pressing equipment (see) Figure 1 As shown, the usage method is as follows:

[0003] 1. Install the fixture base 1' onto the equipment workbench 4', and install the fixture pressure head 2' onto the equipment tailstock 3';

[0004] 2. When using, first install product 5' into the fixture base 1'. The fixture base 1' is positioned in conjunction with the outer circle of product 5'. The outer circle of product 5' is not precision machined after heat treatment, with a tolerance of 0.2. Install bushing 6' into the upper pressure head 2'. The inner hole of bushing 6' is positioned in conjunction with the upper pressure head 2'.

[0005] 3. The movement of the tailstock 3' drives the upper pressure head 2' to move, thereby pressing the bushing 6' into the inner hole of the product 5';

[0006] 4. Move the upper pressure head 2' upwards, remove the product, and complete one pressing process.

[0007] The original solution has the following obvious drawbacks:

[0008] 1. Insufficient concentricity: When the tailstock 3' moves, the concentricity between it and the fixture base 1', the clearance between the fixture and the equipment, and the clearance between the fixture and the product (such as the outer diameter tolerance of the fixture base and the product being 0.2) cause press-fitting eccentricity (the cumulative eccentricity reaches more than 0.3mm), resulting in unilateral stress.

[0009] 2. Quality issues: Bushing shear deformation increases product scrap rate; burrs cause gear cleanliness to exceed standards, leading to customer complaints; unilateral force causes frequent damage to fixtures and equipment;

[0010] 3. High equipment dependence: The precision error of the press fitting machine itself is difficult to eliminate, which restricts the stability of the process. Summary of the Invention

[0011] To overcome the shortcomings of the existing technology, this utility model proposes a floating self-centering fixture structure to improve the accuracy of bushing pressing, which improves the concentricity of pressing, significantly extends the life of the fixture and equipment, and eliminates burrs and improves cleanliness.

[0012] The technical solution adopted in this utility model is:

[0013] A floating self-centering clamping structure for improving bushing pressing accuracy includes a base assembly and an upper pressing head assembly. The base assembly includes a pressing base for supporting the product, and a locating mandrel capable of floating up and down passes through the pressing base. The top end of the locating mandrel can pass through the inner hole of the product to install the bushing. The upper pressing head assembly includes an upper pressing head, and a tip capable of floating up and down passes through the upper pressing head. The tip of the tip protrudes from the upper pressing head and can align with the axis of the locating mandrel. The tip can move downwards, driving the locating mandrel to move downwards and pressing the bushing into the inner hole of the product. This invention dynamically adjusts the concentricity by the up and down movement of the locating pin and the tip, thereby eliminating equipment accuracy errors.

[0014] Furthermore, the top of the positioning mandrel is provided with a central hole that mates with the tip of the center point.

[0015] Furthermore, the upper pressure head is connected to the tailstock of the equipment that drives its up and down movement via an upper connector.

[0016] Furthermore, the upper part of the tip is installed inside the upper connector and a first spring is provided between the tip and the upper connector.

[0017] Furthermore, the first spring is a cylindrical helical compression spring.

[0018] Furthermore, the press-fit base is mounted on the equipment workbench via a flange.

[0019] Furthermore, a second spring is provided between the positioning mandrel and the flange.

[0020] Furthermore, the second spring is a rectangular helical spring.

[0021] Furthermore, the inner hole of the product and the positioning mandrel are fitted with a clearance of H7 / g6.

[0022] Furthermore, the press-fitting between the upper pressure head assembly and the base assembly is carried out in stages.

[0023] The beneficial effects of this utility model are:

[0024] (1) Floating self-centering design: The concentricity is dynamically adjusted by a double spring system (positioning mandrel and center), eliminating equipment accuracy error and improving the press-fit concentricity to 100% qualified;

[0025] (2) Optimization of fit clearance: The inner hole of the product and the mandrel adopt H7 / g6 fit, the clearance is reduced by 0.2 compared with the previous one, the accuracy is improved to 0.025, and the burr and cleanliness problems are completely eliminated;

[0026] (3) Optimization of pressing process: staged pressing (contact → pre-press → in place) avoids impact load and significantly extends the life of fixtures and equipment. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the press-fitting equipment.

[0028] Figure 2 This is a schematic diagram of the existing press-fitting fixture and press-fitting process.

[0029] Figure 3 This is a schematic diagram of the structure of this utility model.

[0030] Figure 4 This is a schematic diagram of the pressing process of this utility model.

[0031] In the diagram: 1. Flange; 2. Second spring; 3. Press-fit base; 4. Positioning mandrel; 5. Upper pressure head; 6. Center; 7. First spring; 8. Upper connector; 9. Product; 10. Bushing; 11. Inner hole; 12. Center hole; 20. Upper pressure head assembly; 30. Base assembly. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements and equivalents that may be included within the scope of the claims.

[0033] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.

[0034] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0035] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0036] See Figure 2 This embodiment provides a floating self-centering fixture structure to improve the pressing accuracy of bushings, including a base assembly 30 and an upper pressing head assembly 20. The base assembly 30 includes a pressing base 3 for supporting the product, and a positioning mandrel 4 that can float up and down is inserted inside the pressing base 3. The top end of the positioning mandrel 4 can pass through the inner hole 11 of the product 9 and install the bushing 10. The upper pressing head assembly 20 includes an upper pressing head 5, and a tip 6 that can float up and down is inserted inside the upper pressing head 5. The tip of the tip 6 protrudes from the upper pressing head 5 and can be aligned with the axis of the positioning mandrel 4. The upper pressing head 5 can move downwards, driving the positioning mandrel 4 to move downwards and pressing the bushing 10 into the inner hole 11 of the product 9. This utility model dynamically adjusts the concentricity by the up and down floating of the positioning mandrel 4 and the tip 6, thereby eliminating equipment accuracy errors.

[0037] In this embodiment, the top center of the positioning mandrel 4 is provided with a central hole 12 that mates with the tip of the center tip 6. The mating of the tip and the central hole enables the upper pressure head and the pressing base to be concentric.

[0038] In this embodiment, the upper pressure head 5 is connected to the tailstock of the equipment that drives its up-and-down movement via an upper connector 8. The upper part of the tip 6 is installed inside the upper connector 8, and a first spring 7 is provided between the tip 6 and the upper connector 8. The first spring 7 allows the tip 7 to float after contacting the positioning mandrel 4, ensuring that the positioning mandrel 4 and the tip 6 are concentric throughout the pressing process. Preferably, the first spring 7 is a cylindrical helical compression spring. The upper end of the cylindrical helical compression spring is connected to the upper connector, and its lower end is installed in the groove of the tip 6. The upper end of the tip 6 has a flange to ensure the reliability of the tip 6 installation and prevent it from coming out of the upper pressure head 5.

[0039] In this embodiment, the press-fit base 3 is mounted on the equipment workbench via a flange 1. A second spring 2 is provided between the positioning mandrel 4 and the flange 1. The positioning mandrel 4 floats up and down under pressure via the second spring 2. Preferably, the second spring 2 is a rectangular helical spring. The lower end of the rectangular helical spring is connected to the flange, and its upper end is fitted onto the lower end of the positioning mandrel 4.

[0040] In this embodiment, the inner hole of product 9 and the positioning mandrel 4 are fitted with a clearance of H7 / g6, which reduces the clearance by 0.2 compared to the previous version, and improves the accuracy to 0.025.

[0041] In this embodiment, the pressing between the upper pressure head assembly 20 and the base assembly 30 is carried out in a staged pressing manner: contact → pre-pressing → in place.

[0042] The pressing process of this utility model is as follows: Figure 4 As shown, the specific steps are as follows:

[0043] (1) Prepare the fixtures and products;

[0044] (2) Insert product 9 into positioning mandrel 4, with product inner hole fitting mandrel H7 / g6;

[0045] (3) Insert the bushing 10 into the positioning mandrel 4, and fit the inner hole;

[0046] (4) The tailstock of the equipment moves down and the pressing process begins; a. The center point 6 contacts the center hole 12 of the positioning mandrel 4, and the upper pressing head 5 and the pressing base 3 are concentric through the contact force of the center hole 12; b. The tailstock of the equipment continues to move, the first spring 7 retracts, and the upper pressing head 5 contacts the bushing 10; c. The tailstock of the equipment continues to move, the upper pressing head 5 contacts the positioning mandrel 4 and continues to move, the second spring 2 retracts, and the bushing 10 is pressed into place;

[0047] (5) The tailstock of the equipment moves upward, and product 9 and positioning spindle 4 spring up together;

[0048] (6) Remove product 9 to complete one pressing process.

[0049] This utility model features a floating self-centering design: A dual-spring system (positioning mandrel and center) dynamically adjusts concentricity, eliminating equipment accuracy errors and improving press-fit concentricity to 100% compliance; Optimized fit clearance: The product's inner hole and mandrel use an H7 / g6 fit, reducing the clearance by 0.2mm compared to before, improving accuracy to 0.025mm, and completely eliminating burr and cleanliness issues; Optimized press-fit process: Staged press-fitting (contact → pre-press → final position) avoids impact loads, significantly extending the lifespan of fixtures and equipment.

Claims

1. A floating self-centering fixture structure for improving the press-fitting accuracy of a bushing, comprising a base assembly and an upper press head assembly, the base assembly comprising a press-fitting base for supporting a product, a positioning mandrel capable of floating up and down being arranged in the press-fitting base, and a top end of the positioning mandrel being capable of passing out of an inner hole of the product to install a bushing; characterized in that: The upper pressure head assembly includes an upper pressure head, inside which is a tip that can float up and down. The tip of the tip protrudes from the upper pressure head and can be aligned with the axis of the positioning mandrel. After the tip moves down, it drives the positioning mandrel to move down and presses the bushing into the inner hole of the product.

2. The floating self-aligning fixture structure for improving the press fitting accuracy of a bushing according to claim 1, characterized in that: The top of the positioning mandrel has a central hole that mates with the tip of the center point.

3. The floating self-centering clamp structure for improving bushing pressing accuracy according to claim 1, characterized in that: The upper pressure head is connected to the tailstock of the equipment that drives it to move up and down via an upper connector.

4. The floating self-centering clamp structure for improving bushing pressing accuracy according to claim 3, characterized in that: The upper part of the tip is installed inside the upper connector and a first spring is provided between the tip and the upper connector.

5. A floating self-centering clamp structure for improving bushing pressing accuracy according to claim 4, characterized in that: The first spring is a cylindrical helical compression spring.

6. The floating self-centering clamp structure for improving bushing pressing accuracy according to claim 1, characterized in that: The press-fit base is mounted on the equipment workbench via a flange.

7. A floating self-centering clamp structure for improving bushing pressing accuracy according to claim 6, characterized in that: A second spring is provided between the positioning mandrel and the flange.

8. The floating self-centering clamp structure for improving bushing pressing accuracy according to claim 7, characterized in that: The second spring is a rectangular helical spring.

9. A floating self-centering clamp structure for improving bushing pressing accuracy according to claim 1, characterized in that: The inner hole of the product and the positioning mandrel are fitted with a clearance of H7 / g6.

10. A floating self-centering clamp structure for improving bushing pressing accuracy according to claim 1, characterized in that: The press-fitting between the upper pressure head assembly and the base assembly is carried out in stages.

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