Centering device and centering method for rotationally symmetric molds

Abstract

This invention provides a centering device and method for a rotary symmetrical mold with high centering accuracy. The centering device for the rotary symmetrical mold includes a rotating table mounted on a base and capable of rotating on the base. A vertical column has a tapered groove at its upper end and a connector at its lower end, which passes through the center hole of a limiting plate and contacts the rotary symmetrical mold. A column is vertically fixed to the base, a lifting guide rail is mounted on the column, and a slider is mounted on the lifting guide rail and can move vertically up and down on it. A fine-tuning device is mounted on the slider, and a cross brace is installed below the fine-tuning device. The cross brace can be used for horizontal position fine-tuning on the fine-tuning device. A tapered block with its cone tip facing downwards is mounted at the bottom of the cross brace. This invention uses a vertical column to control the centering of the rotary symmetrical mold and the precision machining machine, achieving a centering accuracy of up to 0.5μm, an improvement of more than 20 times. It has a simple structure and a long service life.

Description

Technical Field

[0001] This invention belongs to the field of precision machining technology, and particularly relates to a centering device and centering method for a rotationally symmetrical mold. Background Technology

[0002] Rotationally symmetric molds are tools specifically designed for manufacturing rotating parts, which typically exhibit rotational symmetry in shape, such as cylindrical, conical, spherical, and aspherical surfaces. Due to the rotational symmetry of these parts, mold design must ensure the symmetry and consistency of all machined surfaces to guarantee the product's geometric accuracy. Furthermore, rotating parts are widely used in machinery, automotive, and aerospace industries, demanding high dimensional accuracy and surface quality; therefore, mold manufacturing must also meet corresponding high-precision standards. Additionally, some rotating parts possess complex structures, such as threads, concave and convex shapes, and holes; these features must be fully considered in mold design, and appropriate machining methods and process parameters must be selected.

[0003] Machining a rotary symmetrical mold on a CNC machine tool requires mounting the mold on a corresponding fixture. Precise centering is necessary during mounting, ensuring the center of the mold aligns with the center of the machine's rotating mechanism. After centering, locking is performed to prevent vibration during machining due to inaccurate centering, which could affect machining accuracy. CN220178713U discloses a method for controlling the center position of the rotary symmetrical mold by using a limiting groove or slot. However, the machining accuracy of the limiting groove or slot, as well as clamping eccentricity errors, affect the centering level, which can only reach the micrometer level. Furthermore, deformation of the limiting groove or slot further reduces the centering accuracy. Additionally, a single limiting groove size can only be used for rotary symmetrical molds with the same outer diameter. If multiple sizes of rotary symmetrical molds are needed, the limiting grooves must be designed separately, which is very inconvenient in actual industrial production. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a centering device for a rotationally symmetrical mold with high centering accuracy.

[0005] The present invention also provides a centering method using the centering device of the above-mentioned rotationally symmetrical mold.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows: a centering device for a rotary symmetric mold, comprising a vertical rod, a base, a column, a lifting guide rail, a slider, a cross brace, a conical block, a fine-tuning device, a rotating table, and a limiting plate. The rotating table is mounted on the base and can rotate on the base. The upper end of the vertical rod is provided with a groove of a certain taper, and the lower end of the vertical rod is provided with a joint. The joint of the vertical rod passes through the center hole of the limiting plate and contacts the rotary symmetric mold. The column is vertically fixed on the base. The lifting guide rail is mounted on the column. The slider is mounted on the lifting guide rail and can move vertically up and down on the lifting guide rail. The fine-tuning device is mounted on the slider. The cross brace is installed below the fine-tuning device. The cross brace can be finely adjusted in the horizontal direction using the fine-tuning device. The conical block is mounted at the bottom of the cross brace with its cone tip facing down.

[0007] Furthermore, the limiting block is fixed to the base and restricts the downward movement of the slider.

[0008] Furthermore, the taper of the groove in the upright is 90-150°, and the taper of the cone tip of the cone block is 20-60° smaller than the taper of the groove in the upright.

[0009] Furthermore, the length-to-diameter ratio of the upright is 5 to 100.

[0010] Furthermore, the joint of the upright is fixed to the upright with adhesive, and the stiffness of the joint material is less than the stiffness of the material of the rotationally symmetrical mold.

[0011] Furthermore, a central hole is provided on the rotating platform, and the rotating platform rotates on the base (2) via the ball bearing structure.

[0012] Furthermore, the center hole of the limiting plate and the diameter of the upright are reserved with a positive assembly tolerance of 2 micrometers, and the center hole of the rotating table and the diameter of the upright are reserved with a positive assembly tolerance of 2 micrometers.

[0013] A centering method for a rotationally symmetric mold, comprising the following steps:

[0014] 1) The rotary table is installed on the base, and the joint of the upright is inserted into the center hole of the rotary table; the conical block is lowered to a suitable height by the lifting guide rail and the slider, so that the tip of the conical block is placed in the groove of the upright; the rotary table is manually rotated to observe whether the upright as a whole shakes. If there is shaking, the horizontal position of the cross brace on the fine adjustment device is finely adjusted until neither end of the upright shakes with the rotation of the rotary table. At this time, the rotary table and the conical block are in a coaxial state.

[0015] 2) The conical block is lifted by the lifting guide rail and slider, and the upright is removed from the rotating table. An adhesive with a curing time longer than the centering adjustment time is applied to the rotating table. The rotary symmetry mold is placed on the rotating table, and the limiting plate is placed on the rotary symmetry mold. The joint of the upright passes through the center hole of the limiting plate and contacts the rotary symmetry mold. The conical block is lowered by the lifting guide rail and slider, so that the tip of the conical block is placed in the groove of the upright. The rotating table is manually rotated to observe whether the upright shakes. If it shakes, the relative position of the rotary symmetry mold and the rotating table is manually adjusted until neither end of the upright shakes with the rotation of the rotating table. At this time, the rotary symmetry mold and the rotating table are in the same center state.

[0016] Furthermore, the limiting plate is placed on the rotary symmetric mold and holds the rotary symmetric mold in place, so that the rotary symmetric mold and the upright will not deviate excessively during the rotation centering process, and the limiting plate completely covers the rotary symmetric mold, protecting the surface of the rotary symmetric mold to be processed from environmental dust.

[0017] Furthermore, by utilizing the lever amplification principle of the upright, the micron-level deviation of the rotary symmetric mold is amplified by 10 to 200 times on the upright, and centering is achieved by manually adjusting the relative position of the rotary symmetric mold and the rotary table.

[0018] The beneficial effects of this invention are: the method of this invention uses a vertical rod to control the centering of the rotary symmetrical mold and the precision machining machine, and the centering accuracy can reach up to 0.5μm, which is more than 20 times higher than the accuracy; the centering device of this invention does not rely on the machining accuracy of the tooling fixture, nor does it require the use of expensive observation devices, and has a simple structure and low cost; the centering device of this invention does not affect the centering accuracy even if it is deformed after long-term use, and has a long service life. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the centering device of the present invention.

[0020] Figure 2 This is a schematic diagram of the installation of the upright of the centering device of the present invention. Detailed Implementation

[0021] like Figure 1-2 As shown, the centering device of the present invention includes a vertical rod 1, a base 2, a column 3, a lifting guide rail 4, a slider 5, a cross brace 6, a conical block 7, a limiting block 8, a fine-tuning device 9, a rotating table 10, and a limiting disk 20. The rotating table 10 is mounted on the base 2 and can rotate on the base 2 via a ball bearing structure. The rotating table 10 has a central hole. The upper end of the vertical rod 1 has a tapered groove 11, and the lower end of the vertical rod 1 has a joint 12 with a certain rigidity. The joint 12 of the vertical rod 1 passes through the central hole of the limiting disk 20 and contacts the rotationally symmetrical mold 30. Figure 2As shown; the column 3 is vertically fixed on the base 2, the lifting guide rail 4 is set on the column 3, the slider 5 is set on the lifting guide rail 4 and the slider 5 can move vertically up and down on the lifting guide rail 4; the fine adjustment device 9 is installed on the slider 5, and the cross brace 6 is installed below the fine adjustment device 9. The cross brace 6 can be finely adjusted in the horizontal direction on the fine adjustment device 9; the cone block 7 is installed at the bottom of the cross brace 6 with the cone tip facing down; the limit block 8 is fixed on the base 2 and restricts the downward movement of the slider 5 to prevent the slider 5 from falling too far and causing the cone block 7 to hit the base 2; the limit plate 20 is set on the rotary symmetrical mold 30.

[0022] The taper of the aforementioned groove 11 can be 90–150°. The taper of the cone tip of the cone block 7 is 20–60° smaller than the taper of the groove 11 of the upright rod 1, so as to facilitate placing the cone tip of the cone block 7 in the groove 11 of the upright rod 1. The length-to-diameter ratio of the upright rod 1 can be 5–100, so as to use upright rods 1 with different length-to-diameter ratios to change the lever magnification factor. The joint 12 of the upright rod 1 can be fixed to the upright rod 1 with adhesive. The rigidity of the material of the joint 12 is less than the rigidity of the material of the rotationally symmetric mold 30. To avoid scratching the surface of the rotary symmetry mold 30 and to prevent deformation that could affect measurement accuracy during centering, the connector 12 can be made of hard plastics or alloy materials such as PEEK or Teflon. A 2-micron positive fit tolerance is allowed between the center hole of the limiting plate 20 and the diameter of the upright 1, ensuring that the upright 1 will not jam when the connector 12 passes through the center hole of the limiting plate 20, and that the upright 1 will not wobble significantly. The limiting plate 20 can be a cover shape, covering the rotary symmetry mold 30 and securing it in place. Figure 2 As shown; the center hole of the rotary table 10 and the diameter of the upright rod 1 are reserved with a positive assembly tolerance of 2 mils. After the rotary table 10 is removed, it can be used to connect the rotary symmetrical mold 30 and the spindle of the precision machining machine.

[0023] The centering method for the rotationally symmetric mold of the present invention includes the following steps:

[0024] 1) Confirm the coaxiality of the conical block 7 and the rotary table 10.

[0025] The rotary table 10 is installed on the base 2, and the joint 12 of the upright 1 is inserted into the center hole of the rotary table 10. The conical block 7 is lowered to a suitable height by the lifting guide rail 3 and the slider 5, so that the cone tip of the conical block 7 is placed in the groove 11 of the upright 1. The rotary table 10 is manually rotated to observe whether the upright 1 shakes. If it shakes, the horizontal position of the cross brace 6 on the fine adjustment device 9 is finely adjusted until neither end of the upright 1 shakes with the rotation of the rotary table 10. At this time, the rotary table 10 and the conical block 7 are in a coaxial state.

[0026] 2) Confirm that the rotary symmetrical mold 30 and the rotary table 10 are in the same center state.

[0027] Lift the conical block 7 via the lifting guide rail 3 and slider 5, and remove the upright 1 from the rotary table 10; apply an adhesive with a curing time longer than the centering adjustment time onto the rotary table 10; place the rotary symmetry mold 30 on the rotary table 10; place the limiting plate 20 on the rotary symmetry mold 30 and lock it in place, so that the rotary symmetry mold 30 and the upright 1 will not deviate excessively during the rotation and centering process, and the limiting plate 20 completely covers the rotary symmetry mold 30, protecting the rotary symmetry mold 30 from environmental dust contamination of the surface to be processed during the centering process; connect the joint of the upright 1... 12 passes through the center hole of the limiting plate 20 and contacts the rotary symmetry mold 30; lower the cone block 7 through the lifting guide rail 3 and the slider 5 so that the cone tip of the cone block 7 is placed in the groove 11 of the upright 1; manually rotate the rotating table 10 and observe whether the upright 1 shakes. If it shakes, manually adjust the relative position of the rotary symmetry mold 30 and the rotating table 10 (at this time, the adhesive on the rotating table 10 has not yet cured, and the rotary symmetry mold 30 can be moved easily) until neither end of the upright 1 shakes with the rotation of the rotating table 10. At this time, the rotary symmetry mold 30 and the rotating table 10 are in the same center state.

[0028] After the adhesive on the rotary table 10 has cured, remove the upright 1 and the limiting plate 20, lift the conical block 7, and then transfer the rotary table 10 and the fixed rotary symmetrical mold 30 to the precision machining machine for subsequent processing operations.

[0029] This invention utilizes the lever amplification principle of the upright rod 1 to amplify and display the minute deviation of the rotary symmetric mold 30 from the center on the upright rod 1, so that the micron-level deviation can be amplified by 10 to 200 times and thus can be observed with the naked eye. By manually adjusting the relative position of the rotary symmetric mold 30 and the rotating table 10, the centering purpose can be achieved.

[0030] Example 1

[0031] The upright 1 is 100mm long and 10mm in diameter. The groove 11 has a taper of 120°. The connector 12 is made of PEEK rigid plastic. The cone tip of the cone block 7 has a taper of 90°. The rotary symmetrical mold 30 has a diameter of 40mm, a height of 15mm, and a flat upper surface.

[0032] The centering method of this invention is used to achieve a centering accuracy of 5 μm.

[0033] Example 2

[0034] The upright 1 is 200mm long and 5mm in diameter. The groove 11 has a taper of 150°. The connector 12 is made of aluminum alloy. The cone tip of the cone block 7 has a taper of 100°. The rotary symmetric mold 30 has a diameter of 20mm, a height of 12mm, an aspherical upper surface, and a center radius of 25mm.

[0035] The centering method of this invention is used to achieve a centering accuracy of 1 μm.

Claims

1. A centering device for a rotationally symmetrical mold, characterized in that, The system includes a pole (1), a base (2), a column (3), a lifting guide rail (4), a slider (5), a cross brace (6), a conical block (7), a fine-tuning device (9), a rotating platform (10), and a limiting plate (20). The rotating platform (10) is mounted on the base (2) and can rotate on the base (2). The upper end of the pole (1) is provided with a groove (11) of a certain taper, and the lower end of the pole (1) is provided with a joint (12). The joint (12) of the pole (1) passes through the center hole of the limiting plate (20) and contacts the rotary symmetrical mold (30). The column (3) is vertically fixed on the base (2), and the lifting guide rail (4) is mounted on the column (3). The slider (5) is set on the lifting guide rail (4) and the slider (5) can move vertically up and down on the lifting guide rail (4); the fine adjustment device (9) is installed on the slider (5), and the cross brace (6) is installed below the fine adjustment device (9). The cross brace (6) can be finely adjusted in the horizontal direction on the fine adjustment device (9). The cone block (7) is installed at the bottom of the cross brace (6) with the cone tip facing down; the length to diameter ratio of the upright (1) is 5 to 100; the center hole of the limiting plate (20) and the diameter of the upright (1) are reserved with a positive assembly tolerance of 2 mils; the center hole of the rotating table (10) and the diameter of the upright (1) are reserved with a positive assembly tolerance of 2 mils.

2. The centering device for a rotationally symmetrical mold as described in claim 1, characterized in that, The limiting block (8) is fixed on the base (2) and restricts the downward movement of the slider (5).

3. The centering device for a rotationally symmetrical mold as described in claim 1 or 2, characterized in that, The taper of the groove (11) of the upright (1) is 90-150°, and the taper of the cone tip of the cone block (7) is 20-60° smaller than the taper of the groove (11) of the upright (1).

4. The centering device for a rotationally symmetrical mold as described in claim 1 or 2, characterized in that, The joint (12) of the upright (1) is fixed to the upright (1) by adhesive, and the stiffness of the material of the joint (12) is less than the stiffness of the material of the rotationally symmetrical mold (30).

5. The centering device for a rotationally symmetrical mold as described in claim 1 or 2, characterized in that, The rotating platform (10) is provided with a central hole, and the rotating platform (10) rotates on the base (2) through the ball bearing structure of the base (2).

6. A centering method for a rotationally symmetric mold, characterized in that, The method includes the following steps: 1) The rotating table (10) is installed on the base (2), and the joint (12) of the upright (1) is inserted into the center hole of the rotating table (10); the cone block (7) is lowered to a suitable height through the lifting guide rail (4) and the slider (5) so that the cone tip of the cone block (7) is placed in the groove (11) of the upright (1); the rotating table (10) is manually rotated, and the upright (1) is observed to see if it shakes. If it shakes, the horizontal brace (6) is adjusted in the horizontal direction on the fine adjustment device (9) until no end of the upright (1) shakes with the rotation of the rotating table (10). At this time, the rotating table (10) and the cone block (7) are in a coaxial state. 2) The conical block (7) is lifted by the lifting guide rail (4) and the slider (5), and the upright (1) is removed from the rotary table (10). An adhesive with a curing time longer than the centering adjustment time is applied to the rotary table (10). The rotary symmetry mold (30) is placed on the rotary table (10), the limiting plate (20) is placed on the rotary symmetry mold (30), and the joint (12) of the upright (1) passes through the center hole of the limiting plate (20) and contacts the rotary symmetry mold (30). The conical block (7) is lifted by the lifting guide rail (4) and the slider (5). The upright (1) is removed from the rotary table (10), and the rod (1) is removed from the rotary table (10). The joint (12) of the upright (1) passes through the center hole of the limiting plate (20) and contacts the rotary symmetry mold (30). The lifting guide rail (4) and the slider (5) are lowered so that the cone tip of the cone block (7) is placed in the groove (11) of the upright (1); the rotating table (10) is manually rotated to observe whether the upright (1) shakes. If it shakes, the relative position of the rotary symmetric mold (30) and the rotating table (10) is manually adjusted until neither end of the upright (1) shakes with the rotation of the rotating table (10). At this time, the rotary symmetric mold (30) and the rotating table (10) are in the same center state. Using the lever amplification principle of the upright (1), the micron-level deviation of the rotary symmetric mold (30) is amplified by 10 to 200 times on the upright (1), and centering is achieved by manually adjusting the relative position of the rotary symmetric mold (30) and the rotary table (10).

7. The centering method for a rotationally symmetric mold as described in claim 6, characterized in that, The limiting plate (20) is placed on the rotary symmetric mold (30) and holds the rotary symmetric mold (30) in place, so that the rotary symmetric mold (30) and the upright (1) will not deviate excessively during the rotation centering process. The limiting plate (20) covers the rotary symmetric mold (30) as a whole, protecting the surface of the rotary symmetric mold (30) from being contaminated by environmental dust.

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