Pneumatic hydraulic clamping device

Abstract

This invention discloses a pneumatic-hydraulic clamping device, relating to the field of clamping equipment technology. It includes a fixed jaw, a movable jaw, a pneumatically driven hydraulic cylinder, a clamping cylinder, and a control assembly. The pneumatically driven hydraulic cylinder includes a first air chamber and a first oil chamber, while the clamping cylinder includes a second air chamber and a second oil chamber. The first oil outlet of the first oil chamber is connected to the second oil inlet of the clamping cylinder via a one-way valve, and the second oil outlet of the clamping cylinder is connected to the first oil inlet of the first oil chamber via a control valve. The movable jaw is connected to a second piston in the clamping cylinder. This invention uses high-pressure gas to drive hydraulic oil from the first oil chamber into the second oil chamber, pushing the second piston and causing the movable jaw to clamp the workpiece. Simultaneously, a one-way valve is installed between the first oil outlet and the second oil inlet to prevent hydraulic oil backflow and maintain pressure. The incompressible nature of hydraulic oil ensures clamping stability. Furthermore, this invention uses high-pressure gas to drive hydraulic oil, simplifying hydraulic equipment and reducing equipment investment costs.

Description

Technical Field

[0001] This invention relates to the field of clamping equipment technology, and in particular to a pneumatic-hydraulic clamping device. Background Technology

[0002] A bench vise is a commonly used clamping tool in mechanical manufacturing. It is a random accessory for machine tools such as milling machines and drilling machines. It is fixed to the machine tool's worktable to clamp workpieces for cutting and machining; it can also be used to clamp workpieces during benchwork.

[0003] The bench vise currently in widespread use is the screw-driven bench vise, where the movable jaw moves back and forth under the drive of the screw, cooperating with the fixed jaw to clamp and fix the workpiece. This type of mechanical bench vise has a simple structure, but it is relatively troublesome to use. It requires repeatedly shaking the screw to open and close the jaw, which is labor-intensive, has low work efficiency, and the force multiplication factor during clamping is small, affecting its performance.

[0004] To address the problems of manual vises, existing technologies have gradually developed hydraulic vises (such as the invention patent application number "201910180581.4", entitled "A Hydraulic Vise") or pneumatic vises (such as the invention patent application number "201510220209.3", entitled "A Pneumatic Vise"). Both hydraulic and pneumatic vises can achieve automatic control. The advantages of hydraulic vises are stable clamping process and high clamping force; the disadvantages are high cost, large size, and pollution. The advantages of pneumatic vises are simple equipment, ease of use, and relatively fast piston movement speed; the disadvantages are that gas is compressible, resulting in low pressure and difficulty in precise control. Summary of the Invention

[0005] The purpose of this invention is to provide a pneumatic-hydraulic clamping device to solve the problems existing in the prior art. By using high-pressure gas to drive hydraulic oil from the first oil chamber into the second oil chamber, the device pushes the second piston and drives the movable jaws to clamp the workpiece. At the same time, a one-way valve is set between the first oil outlet and the second oil inlet to prevent hydraulic oil backflow and maintain pressure. This not only utilizes the incompressible property of hydraulic oil to ensure clamping stability, but also simplifies the hydraulic equipment and reduces equipment investment costs by using high-pressure gas to drive the hydraulic oil.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides a pneumatic-hydraulic clamping device, including a fixed jaw, a movable jaw, a pneumatically driven hydraulic cylinder, a clamping cylinder, and a control component. The control component includes a two-position four-way directional valve, a high-pressure air inlet, a check valve, and an exhaust port. The pneumatically driven hydraulic cylinder includes a first air chamber and a first oil chamber, and the clamping cylinder includes a second air chamber and a second oil chamber. The P port of the four-way two-position directional valve is connected to the high-pressure air inlet, and the T port of the four-way two-position directional valve is connected to the exhaust port. The A port of the four-way two-position directional valve is connected to the first air chamber, and the B port of the four-way two-position directional valve is connected to the second air chamber; the first oil chamber is provided with a first oil inlet and a first oil outlet, and the clamping cylinder is provided with a second oil inlet and a second oil outlet. The first oil outlet is connected to the second oil inlet through the one-way valve, and the second oil outlet is connected to the first oil inlet through the control valve; the movable jaw is positioned opposite the fixed jaw, and the movable jaw is connected to the second piston in the clamping cylinder.

[0007] Preferably, the control valve includes a pilot check valve, wherein port A of the pilot check valve is connected to the first oil inlet, port B of the pilot check valve is connected to the second oil outlet, and port C of the pilot check valve is connected to port B of the two-way four-position directional valve.

[0008] Preferably, the pneumatic-hydraulic clamping device further includes a pressure regulating passage connected in parallel with the two-position four-way directional valve and the pneumatic-driven hydraulic cylinder; along the gas flow direction, the pressure regulating passage includes a pressure regulating cylinder of a pressure regulating valve and an overflow pressure reducing valve connected in sequence, the pressure regulating inlet of the pressure regulating valve is connected to the high-pressure inlet, the pressure regulating cylinder includes a third piston and a third air chamber and a third adjusting chamber located on both sides of the third piston, the third air chamber is connected to the overflow pressure reducing valve, the piston rod of the third piston is located in the third adjusting chamber, and the end of the piston rod passes out from the adjusting chamber and extends vertically into the pipeline between the first oil outlet and the second oil inlet; a pressure gauge is also provided between the overflow pressure reducing valve and the pressure regulating cylinder.

[0009] Preferably, the pneumatic-hydraulic clamping device further includes a screw, on which a guide nut is threadedly connected, and the guide nut is fixedly connected to the movable jaw; one end of the screw is rotatably connected to the second piston in the clamping cylinder and is limited in the axial direction of the screw, and the other end of the screw is connected to a rotating force-applying part.

[0010] Preferably, the second piston is provided with an axial through hole, and a central screw passes through the axial through hole and is threaded to the end of the screw, so that the second piston abuts against the end of the screw.

[0011] Preferably, the rotating force-applying part includes a rotating handle.

[0012] Preferably, the movable jaw is provided with a receiving groove, and the guide nut has an insertion part that inserts into the receiving groove; along the axial direction of the guide nut, one end face of the insertion part is a first conical surface, and the receiving groove has a second conical surface directly opposite the first conical surface. A groove is provided on the second conical surface, and an adjusting hemisphere is rolled in the groove; a fastening screw coaxial with the guide nut is also threaded onto the movable jaw, and a compression spring is coaxially provided at the end of the fastening screw, abutting against the other end face of the insertion part. Under the action of the compression spring, the first conical surface fits against the plane of the adjusting hemisphere.

[0013] Preferably, both the end of the fixed jaw and the end of the movable jaw opposite it are provided with jaw pads.

[0014] Preferably, it also includes a frame, one end of which is fixed to the control component and the other end of which is fixed to the clamping cylinder; the screw is rotatably mounted on the frame; and the movable jaws are slidably mounted on the frame.

[0015] Preferably, in the moving direction of the movable jaw, a movable cover is provided at the end of the movable jaw, and a fixed cover is also provided on the frame. The fixed cover is located above the screw and is sleeved on the outside of the movable cover.

[0016] The present invention achieves the following technical effects compared to the prior art:

[0017] 1. This invention can drive hydraulic oil from the first oil chamber into the second oil chamber through high-pressure gas to push the second piston and drive the movable jaws to clamp the workpiece. At the same time, a one-way valve is set between the first oil outlet and the second oil inlet to prevent hydraulic oil backflow and maintain pressure. The incompressible property of hydraulic oil can be used to ensure the stability of clamping. In addition, the invention can simplify hydraulic equipment and reduce equipment investment costs by using high-pressure gas to drive hydraulic oil.

[0018] 2. By setting a screw, the position of the movable jaw can be adjusted to be closer to or further away from the fixed jaw without moving the second piston. This reduces the movement distance of the second piston during the clamping or adjustment process before placing the workpiece, allowing the second piston to have a shorter stroke. This reduces the size of the pneumatic hydraulic cylinder and clamping cylinder, further simplifies the structure of the pneumatic hydraulic clamping device, and reduces manufacturing costs. 3. By setting a pressure regulating passage, the present invention makes it easier to accurately control the oil inlet pressure of the clamping cylinder. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of the pneumatic-hydraulic clamping device in this invention;

[0021] Figure 2 This is a bottom view of the pneumatic-hydraulic clamping device in this invention;

[0022] Figure 3 This is a side sectional view of the pneumatic-hydraulic clamping device in this invention;

[0023] Figure 4 This is a schematic diagram of the clamping principle of the pneumatic-hydraulic clamping device in this invention;

[0024] Figure 5 This is a schematic diagram illustrating the release principle of the pneumatic-hydraulic clamping device in this invention.

[0025] The components include: 1. Fixed jaws; 2. Movable jaws; 3. Pneumatic hydraulic cylinder; 4. Clamping cylinder; 5. Control components; 6. Two-position four-way directional valve; 7. Center screw; 8. High-pressure air inlet; 9. Second oil chamber; 10. Second air chamber; 11. Second piston; 12. Check valve; 13. Pilot check valve; 14. Pressure regulating valve; 15. Overflow pressure reducing valve; 16. Pressure regulating cylinder; 17. Screw; 18. Guide nut; 19. Protective cover; 20. Fastening screw; 21. Compression spring; 22. Adjusting hemisphere; 23. Jaw pad; 24. Frame; 25. Fixed cover; 26. Movable cover; 27. Air supply mechanism; 28. Quick connector; 29. ​​Rotating handle; 30. Gas flow pipe; 31. Hydraulic oil flow pipe. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The purpose of this invention is to provide a pneumatic-hydraulic clamping device to solve the problems existing in the prior art. By using high-pressure gas to drive hydraulic oil from the first oil chamber into the second oil chamber, the device pushes the second piston and drives the movable jaws to clamp the workpiece. At the same time, a one-way valve is set between the first oil outlet and the second oil inlet to prevent hydraulic oil backflow and maintain pressure. This not only utilizes the incompressible property of hydraulic oil to ensure clamping stability, but also simplifies the hydraulic equipment and reduces equipment investment costs by using high-pressure gas to drive the hydraulic oil.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] like Figures 1-5 As shown, this embodiment provides a pneumatic-hydraulic clamping device, including a fixed jaw 1, a movable jaw 2, a pneumatic-driven hydraulic cylinder 3, a clamping cylinder 4, and a control component 5. The control component 5 includes a two-position four-way directional valve 6, a high-pressure air inlet 8, a one-way valve 12, and an exhaust port. The high-pressure air inlet 8 is connected to an air supply mechanism via a quick connector 28. The pneumatic-driven hydraulic cylinder 3 includes a first air chamber and a first oil chamber. The clamping cylinder 4 includes a second air chamber 10 and a second oil chamber 9. The P port of the four-way two-position directional valve is connected to the high-pressure air inlet 8. The T port of the directional valve is connected to the exhaust port, the A port of the four-way two-position directional valve is connected to the first air chamber, and the B port of the four-way two-position directional valve is connected to the second air chamber 10; the first oil chamber is provided with a first oil inlet and a first oil outlet, and the clamping cylinder 4 is provided with a second oil inlet and a second oil outlet. The first oil outlet is connected to the second oil inlet through a one-way valve 12, and the second oil outlet is connected to the first oil inlet through a control valve; the movable jaw 2 is positioned opposite the fixed jaw 1, and the movable jaw 2 is connected to the second piston 11 in the clamping cylinder 4.

[0030] During clamping, high-pressure air inlet 8 receives air, which enters the first air chamber of the pneumatic hydraulic cylinder 3 via the two-position four-way directional valve 6, pushing the first piston in the pneumatic hydraulic cylinder 3 to move and expel the hydraulic oil from the first oil chamber. The hydraulic oil enters the second oil chamber 9 of the clamping cylinder 4 via the one-way valve 12, pushing the second piston 11 to move, and the gas in the second air chamber is discharged through the two-position four-way directional valve 6 and the exhaust port. Driven by the second piston 11, the movable jaw 2 moves towards the fixed jaw 1, clamping the workpiece. Because a one-way valve 12 is provided between the first oil outlet and the second oil inlet, backflow of hydraulic oil is prevented, thus maintaining pressure. When released, the two-position four-way directional valve 6 reverses, and high-pressure air inlet 8 enters. The gas enters the second air chamber 10 through the two-position four-way directional valve 6, pushing the second piston 11 to move in the opposite direction. The movable jaw 2 moves with the second piston 11 to release the workpiece. At the same time, the second oil outlet opens, and hydraulic oil enters the first oil chamber from the second oil outlet and the first oil inlet, pushing the first piston to move in the opposite direction and expelling the gas in the first air chamber from the exhaust port.

[0031] Therefore, this embodiment enables high-pressure gas to drive hydraulic oil from the first oil chamber into the second oil chamber 9, pushing the second piston 11 and causing the movable jaw 2 to clamp the workpiece. Simultaneously, a one-way valve 12 is installed between the first oil outlet and the second oil inlet to prevent hydraulic oil backflow and maintain pressure. The incompressible nature of hydraulic oil ensures clamping stability. Furthermore, this embodiment uses high-pressure gas to drive the hydraulic oil, simplifying the hydraulic equipment and reducing equipment investment costs.

[0032] In this embodiment, the two-position four-way directional valve 6 can be either an electromagnetic directional valve or a manual directional valve.

[0033] In this embodiment, the control valve is a pilot-operated check valve 13. Port A of the pilot-operated check valve 13 is connected to the first oil inlet, port B is connected to the second oil outlet, and port C is connected to port B of the two-way four-position directional valve. During clamping, the pilot-operated check valve 13 is not open, and hydraulic oil cannot be discharged from the second oil outlet. During releasing, high-pressure gas acts on the pilot-operated check valve 13, opening it and allowing hydraulic oil to flow from the second oil outlet into the first oil chamber, causing the hydraulic oil to circulate between the first and second oil chambers under the control of the control component 5. Simultaneously, in this embodiment, the first oil outlet and the first oil inlet of the pneumatically driven hydraulic cylinder are the same port.

[0034] When the first piston is driven by high-pressure gas, the pressure loss of the high-pressure gas causes the gas pressure at the high-pressure inlet 8 to differ from the oil pressure at the first oil outlet. Even with a hydraulic oil pressure sensor at the first oil outlet, it is difficult to adjust the oil pressure by adjusting the inlet pressure. In this embodiment, the pneumatic-hydraulic clamping device also includes a pressure regulating passage connected in parallel with the two-position four-way directional valve 6 and the pneumatic-driven hydraulic cylinder 3. Along the gas flow direction, the pressure regulating passage includes a pressure regulating cylinder 16 connected in sequence with a pressure regulating valve 14 and an overflow pressure reducing valve 15. The pressure regulating inlet of the pressure regulating valve 14 is connected to the high-pressure inlet 8. The pressure regulating cylinder 16 includes a third piston and a third air chamber and a third adjusting chamber located on both sides of the third piston. The third air chamber is connected to the overflow pressure reducing valve 15. The piston rod of the third piston is located in the third adjusting chamber, and the end of the piston rod passes through the adjusting chamber and extends vertically into the pipeline between the first oil outlet and the second oil inlet. A pressure gauge is also provided between the overflow pressure reducing valve 15 and the third air chamber. The pressure regulating valve 14 can adjust the air pressure in the pressure regulating passage. Gas enters the third air chamber and applies pressure to the third piston. Hydraulic oil between the first oil outlet and the second oil inlet applies pressure to the third piston through the piston rod. When the third piston is in a balanced state, the pressure on both sides is equal. The reading on the pressure gauge is the inlet oil pressure of the clamping cylinder 4. The overflow pressure of the relief pressure reducing valve 15 is the same as the inlet oil pressure. Therefore, by adjusting the pressure regulating valve 14 and the overflow pressure reducing valve 15, the inlet oil pressure of the clamping cylinder 4 can be adjusted.

[0035] Furthermore, in this embodiment, the pneumatic-hydraulic clamping device also includes a screw 17, on which a guide nut 18 is threadedly connected, and the guide nut 18 is fixedly connected to the movable jaw 2; the second piston 11 is provided with an axial through hole, and a central screw 7 passes through the axial through hole and is threadedly connected to one end of the screw 17, so that the second piston 11 abuts against the end of the screw 17, and the other end of the screw 17 is connected to a rotating force-applying part. Typically, the force-applying part is a rotating handle 29.

[0036] In use, first rotate the screw 17 by turning the handle 29, causing the guide nut 18 to move the movable jaw 2 away from the fixed jaw 1. Then, place the workpiece between the fixed jaw 1 and the movable jaw 2, and rotate the screw 17 to bring the movable jaw 2 closer to the fixed jaw 1. When the distance between the movable jaw 2 and the workpiece is less than the clamping stroke of the second piston 11, stop rotating the screw 17, and introduce high-pressure gas into the high-pressure air inlet 8. The hydraulic oil in the second oil chamber 9 pushes the second piston 11 to move, causing the movable jaw 2 to clamp the workpiece.

[0037] In this embodiment, by setting the screw 17, the position of the movable jaw 2 can be adjusted without moving the second piston 11, so that it is closer to or farther away from the fixed jaw 1. This reduces the movement distance of the second piston 11 during the clamping of the workpiece or the adjustment process before placing the workpiece, allowing the second piston 11 to have a shorter stroke. This reduces the volume of the pneumatic hydraulic cylinder and the clamping cylinder 4, further simplifies the structure of the pneumatic hydraulic clamping device, and reduces manufacturing costs.

[0038] Furthermore, in this embodiment, the movable jaw 2 is provided with a receiving groove, and the guide nut 18 has an insertion part for inserting into the receiving groove; along the axial direction of the guide nut 18, one end face of the insertion part is a first conical surface, and the receiving groove has a second conical surface that is directly opposite to the first conical surface. A groove is provided on the second conical surface, and an adjusting hemisphere 22 is rolled in the groove; the movable jaw 2 is also threadedly connected with a fastening screw 20 coaxial with the guide nut 18, and a compression spring 21 is coaxially provided at the end of the fastening screw 20 that abuts against the other end face of the insertion part. Under the action of the compression spring 21, the first conical surface fits against the plane of the adjusting hemisphere 22.

[0039] Furthermore, in this embodiment, both the end of the fixed jaw 1 and the end of the movable jaw 2 opposite to it are provided with jaw pads 23.

[0040] This embodiment also includes a frame 24. A control component 5 (including the pressure regulating valve 14 and overflow pressure reducing valve 15 in the pressure regulating passage) is fixed to one end of the frame 24, and a clamping cylinder 4 is fixed to the other end. A protective cover 19 is provided outside the control component 5. Both the pneumatic hydraulic cylinder and the pressure regulating cylinder 16 are housed within the protective cover 19. A gas flow pipe 30 and a hydraulic oil flow pipe 31 connect the clamping cylinder 4 and the pneumatic hydraulic cylinder. The screw 17 is rotatably mounted on the frame 24. The movable jaw 2 is slidably mounted on the frame 24. A movable cover 27 is provided at the end of the movable jaw 2 in the direction of movement. A fixed cover 25 is also provided on the frame 24, located above the screw 17 and fitted over the movable cover 27. The fixed cover 25 and the movable cover 27 prevent dust or chips from falling onto the surface of the screw 17 and inside the frame 24.

[0041] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0042] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A pneumatic-hydraulic clamping device, characterized in that, The device includes a fixed jaw, a movable jaw, a pneumatically driven hydraulic cylinder, a clamping cylinder, and a control assembly. The control assembly includes a two-position four-way directional valve, a high-pressure air inlet, a check valve, and an exhaust port. The pneumatically driven hydraulic cylinder includes a first air chamber and a first oil chamber. The clamping cylinder includes a second air chamber and a second oil chamber. The P port of the two-position four-way directional valve is connected to the high-pressure air inlet, the T port is connected to the exhaust port, the A port is connected to the first air chamber, and the B port is connected to the second air chamber. The first oil chamber has a first oil inlet and a first oil outlet. The clamping cylinder has a second oil inlet and a second oil outlet. The first oil outlet is connected to the second oil inlet via the check valve, and the second oil outlet is connected to the first oil inlet via a control valve. The movable jaw is positioned opposite the fixed jaw and is connected to a second piston in the clamping cylinder. The pneumatic-hydraulic clamping device also includes a pressure regulating passage connected in parallel with the two-position four-way reversing valve and the pneumatic-driven hydraulic cylinder; along the gas flow direction, the pressure regulating passage includes a pressure regulating valve and a pressure regulating cylinder connected in sequence, the pressure regulating inlet of the pressure regulating valve is connected to the high-pressure inlet, the pressure regulating cylinder includes a third piston and a third air chamber and a third adjusting chamber located on both sides of the third piston, the third air chamber is connected to the overflow pressure reducing valve, the piston rod of the third piston is located in the third adjusting chamber, and the end of the piston rod passes out from the third adjusting chamber and extends vertically into the pipeline between the first oil outlet and the second oil inlet; a pressure gauge is also provided between the overflow pressure reducing valve and the pressure regulating cylinder.

2. The pneumatic-hydraulic clamping device according to claim 1, characterized in that, The control valve includes a pilot check valve, wherein port A of the pilot check valve is connected to the first oil inlet, port B of the pilot check valve is connected to the second oil outlet, and port C of the pilot check valve is connected to port B of the two-way four-position directional valve.

3. The pneumatic-hydraulic clamping device according to claim 1 or 2, characterized in that, The pneumatic-hydraulic clamping device further includes a screw, on which a guide nut is threadedly connected, and the guide nut is fixedly connected to the movable jaw; one end of the screw is rotatably connected to the second piston in the clamping cylinder and is limited in the axial direction of the screw, and the other end of the screw is connected to the rotating force application part.

4. The pneumatic-hydraulic clamping device according to claim 3, characterized in that, The second piston is provided with an axial through hole, and a central screw passes through the axial through hole and is threaded to the end of the screw, so that the second piston abuts against the end of the screw.

5. The pneumatic-hydraulic clamping device according to claim 4, characterized in that, The rotating force-applying part includes a rotating handle.

6. The pneumatic-hydraulic clamping device according to claim 4, characterized in that, The movable jaws are provided with a receiving groove, and the guide nut has an insertion part that inserts into the receiving groove; along the axial direction of the guide nut, one end face of the insertion part is a first conical surface, and the receiving groove has a second conical surface that is directly opposite to the first conical surface. A groove is provided on the second conical surface, and an adjusting hemisphere is rolled in the groove; a fastening screw coaxial with the guide nut is also threaded onto the movable jaws, and a compression spring is coaxially provided at the end of the fastening screw, abutting against the other end face of the insertion part. Under the action of the compression spring, the first conical surface fits against the plane of the adjusting hemisphere.

7. The pneumatic-hydraulic clamping device according to claim 6, characterized in that, Both the fixed jaw and the opposite end of the movable jaw are provided with jaw pads.

8. The pneumatic-hydraulic clamping device according to claim 6, characterized in that, It also includes a frame, one end of which is fixed to the control component and the other end of which is fixed to the clamping cylinder; the screw is rotatably mounted on the frame; and the movable jaws are slidably mounted on the frame.

9. The pneumatic-hydraulic clamping device according to claim 8, characterized in that, In the moving direction of the movable jaw, a movable cover is provided at the end of the movable jaw, and a fixed cover is also provided on the frame. The fixed cover is located above the screw and is sleeved on the outside of the movable cover.

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