CNC positioning jig based on pneumatic driving

Abstract

The utility model relates to a CNC (Computer Numerical Control) positioning jig based on pneumatic driving, which comprises a box body, the inside of the box body is a sealed cavity, a thin film sheet is arranged in the center of the top of the box body, a positioning plate is arranged in the center of the thin film sheet, the thin film sheet and the positioning plate are made of elastic materials, and an elastic chuck is arranged on the positioning plate. The side face and the bottom of the box body communicate with a positive pressure pipeline and a negative pressure pipeline correspondingly, and pressure maintaining valves are installed on the positive pressure pipeline and the negative pressure pipeline correspondingly. According to the utility model, gas is filled into the box body by utilizing the positive pressure pipeline, so that a film sheet can be uniformly expanded outwards to drive the elastic chuck to uniformly expand, a workpiece can be uniformly supported, the positioning precision of the workpiece is improved, and the machining precision of CNC is further improved; gas in the box body is exhausted through the negative pressure pipeline, so that the film piece can be evenly expanded inwards to drive the elastic chuck to evenly contract, the contraction force of the elastic chuck is controlled by controlling the gas displacement through the pressure stabilizing valve, the outer wall of a workpiece is prevented from being damaged, and the workpiece can be evenly and firmly clamped.

Description

Technical Field

[0001] The utility model relates to the technical field of precision clamps, in particular to a CNC positioning fixture based on air pressure drive. Background Art

[0002] When a CNC machine performs precision machining on a workpiece, it is necessary to use a positioning fixture to accurately position the workpiece, and high consistency in repeated positioning is required. There are many types of CNC positioning fixtures, among which the elastic chuck is a commonly used positioning fixture. For a workpiece that needs to be clamped from the inside, when the elastic chuck acts on the inner wall of the workpiece, the elastic chuck expands to hold the workpiece, and the elastic chuck contracts to release the workpiece. For a workpiece that needs to be clamped from the outside, when the elastic chuck acts on the outer wall of the workpiece, the elastic chuck contracts to clamp the workpiece, and the elastic chuck expands to release the workpiece.

[0003] The existing elastic chuck positioning fixture uses an inner support rod to control the contraction and expansion of the elastic chuck. The inner support rod is connected to the cylinder piston. The insertion and extraction power of the inner support rod is provided by the cylinder. The elastic chuck expands with the insertion of the inner support rod and contracts with the extraction of the inner support rod. In actual use, the existing elastic chuck positioning fixture has the following problems:

[0004] 1. When the elastic chuck acts on the inner wall of the workpiece, when the inner support rod is inserted, the extrusion force of each spring of the elastic chuck is uneven, which will cause the workpiece position to be offset, the workpiece positioning is not accurate enough, and the CNC processing accuracy is reduced;

[0005] 2. When the elastic chuck acts on the outer wall of the workpiece, the inner support rod cannot provide contraction force for the elastic chuck. The contraction force of the elastic chuck comes from its own elastic force. Therefore, the contraction force of the elastic chuck cannot be accurately controlled. Excessive contraction force will damage the outer wall of the workpiece. Too little contraction force will cause the workpiece to be unreliably fixed, reducing the CNC machining accuracy. Utility Model Content

[0006] The purpose of the utility model is to design a CNC positioning fixture based on air pressure drive, so that it can solve the problems mentioned in the background technology.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] A CNC positioning fixture based on air pressure drive includes a box body, the interior of the box body is a sealed cavity, a film is provided at the top center of the box body, a positioning plate is provided at the center of the film, the film and the positioning plate are both made of elastic materials, an elastic chuck is installed on the positioning plate, the side and bottom of the box body are respectively connected to a positive pressure pipeline and a negative pressure pipeline, and pressure-stabilizing valves are installed on the positive pressure pipeline and the negative pressure pipeline.

[0009] Furthermore, a bottom plate is fixedly connected to the bottom of the box body, a first air hole is provided on the side of the bottom plate, a second air hole connected to the bottom of the box body is provided on the top of the bottom plate, the first air hole is connected to the second air hole, and the air inlet of the negative pressure pipeline is connected to the first air hole.

[0010] Furthermore, a cover shell for covering the elastic clamp is placed on the top of the box body, an operating hole cooperating with the elastic clamp is provided on the top of the cover shell, the clamp end of the elastic clamp passes through the operating hole, and a circular ring plate surrounding the operating hole is provided on the top of the cover shell.

[0011] Furthermore, the cover shell is provided with a plurality of first screw holes distributed on its circumference, the box body is provided with second screw holes corresponding one-to-one to the first screw holes, and the first screw holes and the second screw holes are connected by first screws.

[0012] Furthermore, the elastic clamp includes a plurality of circumferentially distributed clamping petals, a slit is provided between adjacent clamping petals, a third screw hole is provided on the clamping petal, a fourth screw hole corresponding to the third screw hole is provided on the positioning plate, and the third screw hole and the fourth screw hole are connected by a second screw.

[0013] Furthermore, two adjacent clamping petals are provided with arc-shaped plates cooperating with the workpiece.

[0014] Furthermore, a pressure-stabilizing valve is installed on the positive pressure pipeline.

[0015] Furthermore, the ends of the positive-pressure pipeline and the negative-pressure pipeline away from the box body are both connected to an air compressor.

[0016] The beneficial effects of the utility model are:

[0017] When the elastic chuck acts on the inner wall of the workpiece, the positive pressure pipeline is used to fill the box with gas. The positive air pressure in the box will push the film to expand outside the box. Since the positive air pressure in the box is uniform in all directions, the film can expand outward evenly, driving the elastic chuck to expand evenly, and can evenly tighten the workpiece, improve the positioning accuracy of the workpiece, and thus improve the processing accuracy of CNC.

[0018] When the elastic chuck acts on the outer wall of the workpiece, the gas in the box is discharged by using the negative pressure pipeline. The box is in a negative pressure state, and the air pressure outside the box will push the film to expand into the inside of the box. Since the negative air pressure in the box is uniform in all directions, the film can expand inward evenly, driving the elastic chuck to shrink evenly. The contraction force of the elastic chuck is controlled by controlling the exhaust volume through the pressure-stabilizing valve, avoiding damage to the outer wall of the workpiece, and can also clamp the workpiece evenly and firmly, thereby improving the processing accuracy of CNC. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the structure of the utility model;

[0021] Figure 2 It is a cross-sectional view of the utility model;

[0022] Figure 3 This is a schematic diagram of the structure of the cover shell in the utility model;

[0023] Figure 4 It is a structural schematic diagram of the elastic chuck in the utility model;

[0024] Figure 5 It is a schematic diagram of the expanded structure of the utility model for clamping the inside of a workpiece.

[0025] The names of the components marked in the figure are as follows:

[0026] 1. Box body; 2. Diaphragm; 3. Positioning plate; 4. Elastic chuck; 5. Positive pressure pipeline; 6. Negative pressure pipeline; 7. Bottom plate; 8. First air hole; 9. Second air hole; 10. Cover shell; 11. Working hole; 12. Circular ring plate; 13. First screw hole; 14. Second screw hole; 15. Clamp; 16. Third screw hole; 17. Fourth screw hole; 18. Arc plate; 19. Pressure regulating valve. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the utility model, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0028] like Figure 1-5As shown, a CNC positioning fixture based on air pressure drive includes a box body 1, the interior of the box body 1 is a sealed cavity, a film sheet 2 is provided at the top center of the box body 1, a positioning plate 3 is provided at the center of the film sheet 2, the film sheet 2 and the positioning plate 3 are both made of elastic materials, and an elastic chuck 4 is installed on the positioning plate 3, and the elastic chuck 4 is driven to expand or contract through the expansion of the elastic film sheet 2 and the positioning plate 3; a bottom plate 7 is fixedly connected to the bottom of the box body 1, a first air hole 8 is provided on the side of the bottom plate 7, and a top of the bottom plate 7 is provided with a first air hole 8 that is connected to the box body 1 The second air hole 9 connected to the bottom of the box 1, the first air hole 8 is connected to the second air hole 9, the side of the box 1 is connected to the positive pressure pipeline 5, the first air hole 8 is connected to the negative pressure pipeline 6, and the positive pressure pipeline 5 and the negative pressure pipeline 6 are both installed with a pressure stabilizing valve 19, and the pressure stabilizing valve 19 is used to control the air intake of the positive pressure pipeline 5 and the exhaust volume of the negative pressure pipeline 6; the positive pressure pipeline 5 and the negative pressure pipeline 6 are connected to an air compressor at one end away from the box 1, and the air compressor fills the box 1 with gas through the positive pressure pipeline 5, or the air compressor discharges the gas in the box 1 through the negative pressure pipeline 6;

[0029] A cover shell 10 for covering the elastic chuck 4 is placed on the top of the box body 1, which has the function of protecting the elastic chuck 4; an operating hole 11 is provided on the top of the cover shell 10 to match the elastic chuck 4, and the chuck end of the elastic chuck 4 passes through the operating hole 11. A circular plate 12 surrounding the operating hole 11 is provided on the top of the cover shell 10, which is used to place the workpiece that needs to be clamped from the inside on the circular plate 12 to maintain the balance of the workpiece; a plurality of first screw holes 13 are distributed on the circumference of the cover shell 10, and second screw holes 14 corresponding to the first screw holes 13 are provided on the box body 1. The first screw holes 13 and the second screw holes 14 are connected by first screws, which is convenient for fixing or disassembling the cover shell 10;

[0030] The elastic chuck 4 includes a plurality of circumferentially distributed clamping petals 15, with slits provided between adjacent clamping petals 15, a third screw hole 16 provided on the clamping petal 15, a fourth screw hole 17 corresponding to the third screw hole 16 on the positioning plate 3, and the third screw hole 16 and the fourth screw hole 17 are connected by a second screw, so as to facilitate the fixing or disassembly of the elastic chuck 4; wherein two adjacent clamping petals 15 are provided with an arc-shaped plate 18 cooperating with the workpiece, and the structure of the clamping petal 15 is modified according to the shape changes of different workpieces.

[0031] Working principle:

[0032] like Figure 1-5As shown, when the CNC positioning fixture is in use, in the case of processing a workpiece that needs to be clamped from the inside, the workpiece is placed on the annular plate 12 and aligned with the clamping end of the elastic clamp 4, and then the air compressor is started. The air compressor fills gas into the box body 1 through the positive pressure pipeline 5, and adjusts the air intake of the positive pressure pipeline 5 through the pressure regulating valve 19 on the positive pressure pipeline 5. The positive air pressure in the box body 1 will push the film 2 to expand outside the box body 1. Since the positive air pressure in the box body 1 is isotropic, the film 2 can expand evenly outward, driving the elastic clamp 4 to relax evenly and evenly tighten the workpiece. When the workpiece needs to be removed, it is only necessary to start the air compressor, and the air compressor discharges the gas in the box body 1 through the negative pressure pipeline 6, and the elastic clamp 4 will loosen the workpiece;

[0033] When processing a workpiece that needs to be clamped from the outside, the part of the workpiece that needs to be clamped is placed in the clamping end of the elastic clamp 4, and then the air compressor is started. The air compressor discharges the gas in the box body 1 through the negative pressure pipeline 6, and adjusts the exhaust volume of the negative pressure pipeline 6 through the pressure-stabilizing valve 19 on the negative pressure pipeline 6. The box body 1 is in a negative pressure state, and the air pressure outside the box body 1 will push the film 2 to expand toward the inside of the box body 1. Since the negative air pressure in the box body 1 is isotropic, the film 2 can expand inward evenly, driving the elastic clamp 4 to contract evenly. The exhaust volume is controlled by the pressure-stabilizing valve 19 to control the contraction force of the elastic clamp 4, so as to avoid damaging the outer wall of the workpiece and to clamp the workpiece evenly and securely. When the workpiece needs to be removed, it is only necessary to start the air compressor. The air compressor fills gas into the box body 1 through the positive pressure pipeline 5, and the elastic clamp 4 will release the workpiece.

[0034] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A CNC positioning fixture based on air pressure drive, characterized in that: The invention comprises a box body (1), the interior of the box body (1) is a sealed cavity, a film (2) is provided at the center of the top of the box body (1), a positioning plate (3) is provided at the center of the film (2), the film (2) and the positioning plate (3) are both made of elastic materials, an elastic clamp (4) is installed on the positioning plate (3), the side and bottom of the box body (1) are respectively connected to a positive pressure pipeline (5) and a negative pressure pipeline (6), and a pressure stabilizing valve (19) is installed on both the positive pressure pipeline (5) and the negative pressure pipeline (6).

2. The pneumatically driven CNC positioning fixture according to claim 1, characterized in that: The bottom of the box body (1) is fixedly connected to a bottom plate (7), a first air hole (8) is provided on the side of the bottom plate (7), a second air hole (9) connected to the bottom of the box body (1) is provided on the top of the bottom plate (7), the first air hole (8) is connected to the second air hole (9), and the air inlet of the negative pressure pipeline (6) is connected to the first air hole (8).

3. The pneumatically driven CNC positioning fixture according to claim 1, characterized in that: A cover shell (10) for covering the elastic clamp (4) is placed on the top of the box body (1); an operating hole (11) cooperating with the elastic clamp (4) is provided on the top of the cover shell (10); a clamp end of the elastic clamp (4) passes through the operating hole (11); and a circular ring plate (12) surrounding the operating hole (11) is provided on the top of the cover shell (10).

4. The pneumatically driven CNC positioning fixture according to claim 3, characterized in that: A plurality of first screw holes (13) are distributed on the circumference of the cover shell (10), and second screw holes (14) corresponding to the first screw holes (13) are provided on the box body (1), and the first screw holes (13) and the second screw holes (14) are connected by first screws.

5. The pneumatically driven CNC positioning fixture according to claim 1, characterized in that: The elastic clamp (4) comprises a plurality of circumferentially distributed clamping petals (15), a slot is provided between adjacent clamping petals (15), a third screw hole (16) is provided on the clamping petals (15), a fourth screw hole (17) corresponding to the third screw hole (16) is provided on the positioning plate (3), and the third screw hole (16) and the fourth screw hole (17) are connected by a second screw.

6. The pneumatically driven CNC positioning fixture according to claim 5, characterized in that: Two adjacent clamping petals (15) are provided with arc-shaped plates (18) that match the workpiece.

7. The pneumatically driven CNC positioning fixture according to claim 1, characterized in that: The ends of the positive pressure pipeline (5) and the negative pressure pipeline (6) away from the box body (1) are both connected to an air compressor.

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