Pneumatic clamping device

Abstract

The utility model discloses a kind of pneumatic clamping devices, solve current relevant pneumatic clamp, processing precision is lower, and due to the technical problem that pneumatic clamp is rotated with workpiece and leads to gas path connection is limited, by being a complete pneumatic structure with cylinder and piston, piston divides cylinder into upper / lower chamber, first air inlet and outlet passage and second air inlet and outlet passage are respectively at the upper and lower sides of piston, compressed gas enters upper chamber or lower chamber, and pushes piston to move up / down. First annular air groove and second annular air groove are set on the outer wall of cylinder cylindrical portion, at the instant of air intake, first annular air groove and second annular air groove will form a small pressure vessel, reduce the greater impact force brought by compressed gas at the instant of air intake, increase the overall strength and its pressure resistance of pneumatic clamping device structure, improve the stability of pneumatic clamping device, and then guarantee the press-fitting precision of workpiece to be processed.

Description

Technical Field

[0001] This utility model relates to clamping devices, specifically to a pneumatic clamping device. Background Technology

[0002] In recent years, the processing and manufacturing industry has developed rapidly, high-speed cutting technology has continued to advance, machining time has been reduced accordingly, and production efficiency has been continuously improved. Improving process equipment and shortening pre-processing preparation time have become important development directions for improving production efficiency.

[0003] High-speed cutting, due to its high cutting speed, high feed efficiency, and stringent machining accuracy requirements, demands extremely high standards in its preparatory work, requiring comprehensive control over multiple aspects, including equipment, cutting tools, workpieces, and processes. Among these, workpiece clamping typically requires the use of highly rigid and precisely positioned pneumatic clamps to ensure secure clamping, uniform clamping force, and to prevent workpiece loosening or deformation during high-speed cutting. Simultaneously, the clamps must be securely connected to the worktable to prevent overall vibration.

[0004] However, existing pneumatic clamps mainly consist of a cylinder, a piston, and a piston rod. Compressed air enters the cylinder, pushing the piston to reciprocate within the cylinder. The piston rod connects the piston and the clamp body, transmitting the piston's motion to the clamp body to clamp and release the workpiece. Limited by the characteristics of the pneumatic structure, the controllability of air pressure and flow is poor, making it difficult to ensure motion stability and resulting in lower workpiece machining accuracy. Furthermore, because the pneumatic clamp needs to rotate with the workpiece to perform cutting operations, connecting the air circuit can be difficult. Utility Model Content

[0005] The purpose of this utility model is to solve the technical problems of existing pneumatic clamps, which are limited by the characteristics of pneumatic structure, have poor controllability of air pressure and flow, make it difficult to ensure motion stability, resulting in low workpiece processing accuracy, and make air circuit connection difficult because the pneumatic clamp needs to rotate with the workpiece. Therefore, this utility model provides a pneumatic clamping device.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is: a pneumatic clamping device, which is characterized by including a cylinder, a piston, a connecting sleeve, an upper pressure cover, and a workpiece mounting assembly.

[0007] The bottom of the cylinder is a frustum, and the top is a cylindrical part coaxially connected to the frustum, with the diameter of the cylindrical part being smaller than the diameter of the frustum.

[0008] The piston is installed inside the frustum section, which divides the interior of the frustum section into an upper chamber and a lower chamber.

[0009] The cylindrical part has a first through hole, a first air inlet and outlet passage and a second air inlet and outlet passage, and a first annular air groove and a second annular air groove are provided on the outer wall of the cylindrical part along the circumferential direction; the first ends of the first air inlet and outlet passage and the second air inlet and outlet passage are respectively connected to the upper chamber and the lower chamber, and the second ends are respectively connected to the first annular air groove and the second annular air groove.

[0010] The connecting sleeve is fitted onto the cylindrical part, and each end of the sleeve has a countersunk plate. Each countersunk plate contains a bearing. The outer rings of the two bearings are interference-fitted with the connecting sleeve, and the inner rings of the bearings are interference-fitted with the outer wall of the cylindrical part, so that the cylindrical part can rotate relative to the connecting sleeve. The inner wall of the connecting sleeve and the outer wall of the cylindrical part are sealed. The connecting sleeve has a first air hole and a second air hole in the radial direction. The outer ends of the first air hole and the second air hole are connected to an external air source, and their inner ends are respectively connected to the first annular air groove and the second annular air groove.

[0011] The upper pressure cap is connected to the top surface of the cylindrical part so that the inner rings of the two bearings are pressed between the upper pressure cap and the frustum part; a gap is left between the lower end of the connecting sleeve and the frustum part.

[0012] The workpiece mounting assembly is mounted on the top of the upper pressure cover. The workpiece mounting assembly includes a clamping head, the small end of which passes through the first through hole and is connected to the piston to lock and release the workpiece to be processed mounted on the workpiece mounting assembly.

[0013] Furthermore, the first air inlet / outlet passage and the second air inlet / outlet passage respectively include a first air passage and a second air passage arranged along the axial direction of the cylindrical portion, and a first air channel and a second air channel arranged along its radial direction. The lower end of the first air passage is connected to the upper chamber, and the upper end is connected to the first air channel. The lower end of the second air passage is connected to the lower chamber through a third air passage, and the upper end is connected to the second air channel. The first annular air groove and the second annular air groove are located at the outer ends of the first air channel and the second air channel, respectively.

[0014] The third air passage includes a third air channel arranged radially along the frustum portion and a fourth air channel arranged axially along the frustum portion, and the third air channel and the fourth air channel are connected. The lower end of the second air passage is connected to the third air channel, and the lower end of the fourth air channel is connected to the lower chamber.

[0015] Furthermore, the upper pressure cover has an annular boss on the side near the bearing that corresponds to the inner ring of the bearing, and the connection between the cylindrical part and the frustum part has an annular limiting step that corresponds to the inner ring of the bearing. The upper pressure cover is connected to the top surface of the cylindrical part so that the inner rings of the two bearings are clamped and limited by the annular boss and the annular limiting step.

[0016] Furthermore, the workpiece mounting assembly also includes a workpiece mounting base, one end of which is connected to the upper pressure cover, and the other end has a workpiece mounting position. The small end of the clamping head passes through a through hole at the axis of the workpiece mounting base, and an annular flat washer is fitted on the small end of the clamping head.

[0017] Furthermore, the annular flat pad has an installation notch, defined as follows: the diameter of the small end of the pressing head is D1, and the maximum opening distance of the installation notch is D2, then D1≤D2≤1.3D1.

[0018] Furthermore, the pneumatic clamping device also includes a mounting base, which is connected to the bottom surface of the frustum portion, and the mounting base has a guide channel on the side near the cylinder.

[0019] The piston has a first guide post and a second guide post at its two ends, respectively. The first guide post is located in the first through hole, and the second guide post is located in the guide channel. The small end of the pressing head is connected to the first guide post.

[0020] Furthermore, the pneumatic clamping device also includes a connecting shaft, and the small end of the clamping head is connected to the first guide post through the connecting shaft.

[0021] Furthermore, the piston has a threaded hole that passes through the first guide post and the second guide post, the lower end of the connecting shaft is located in the threaded hole, and the other end is connected to the small end of the clamping head.

[0022] Furthermore, if the height of the mounting base is defined as h1 and the height of the frustum is defined as h2, then 0.8h2≤h1≤1.1h2.

[0023] Furthermore, the piston has annular bosses on both its upper and lower end faces, with the two annular bosses located on the periphery of the first guide post and the second guide post, respectively.

[0024] The advantages of this utility model compared to the prior art are:

[0025] 1. This utility model discloses a pneumatic clamping device. The cylinder and piston form a complete pneumatic structure. The piston divides the cylinder into an upper chamber and a lower chamber. A first and second air inlet / outlet passage are located on the cylinder, respectively on the upper and lower sides of the piston. Compressed gas enters the upper or lower chamber, pushing the piston up / down. A first and second annular groove are provided on the outer wall of the cylindrical part of the cylinder. At the moment of air intake, the first and second annular grooves form a small pressure vessel, reducing the large impact force brought by the compressed gas intake, increasing the overall strength and pressure resistance of the pneumatic clamping device structure, improving the stability of the pneumatic clamping device, and thus ensuring the pressing accuracy of the workpiece to be processed. Furthermore, the air source is connected to the outer wall of the connecting sleeve and does not rotate with the workpiece to be processed, thus freeing the air path connection from restriction.

[0026] 2. This utility model discloses a pneumatic clamping device in which the connecting sleeve and the cylinder are supported by double bearings, reducing the impact force on the workpiece during the air intake process and thus weakening the impact of the air intake process on the workpiece. Furthermore, the high rotational speed of the bearings, small radial clearance, and ability to withstand large radial and axial loads further improve the accuracy and stability of this pneumatic clamping device.

[0027] 3. The present invention provides a pneumatic clamping device, wherein a first guide post and a second guide post are provided on the piston, and a through threaded hole is provided to accommodate a portion of the unused connecting shaft, thereby increasing the adjustment range of the connecting shaft and enabling the clamping head to clamp workpieces of different heights.

[0028] 4. The present invention provides a pneumatic clamping device, wherein the height of the mounting base 1 is h1 and the height of the frustum is h2. The heights of the two satisfy the following condition: 0.8h2≤h1≤1.1h2. Since the height of the machining tool is limited, increasing the height of the mounting base and reducing the height of the frustum is more conducive to machining stability.

[0029] 5. This utility model provides a pneumatic clamping device with an annular flat pad. The annular flat pad has high planar accuracy, which can ensure that the workpiece to be processed will not be tilted under force, and effectively avoid deformation or movement of the workpiece to be processed caused by uneven force. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view (including part of the mounting base) of an embodiment of a pneumatic clamping device according to the present invention;

[0031] Figure 2 This is a cross-sectional view of the cylinder, piston, and bearing in an embodiment of a pneumatic clamping device according to the present invention.

[0032] Figure 3 This is a cross-sectional view of the cylinder in an embodiment of the pneumatic clamping device of this utility model;

[0033] Figure 4 This is a cross-sectional view of the connecting sleeve in an embodiment of the pneumatic clamping device of this utility model.

[0034] The annotations in the attached figures are explained as follows:

[0035] 1. Mounting base; 2. Cylinder; 201. First annular air groove; 202. Second annular air groove; 3. Piston; 301. First guide post; 302. Second guide post; 4. Connecting sleeve; 401. Sealing groove; 5. Upper pressure cover; 6. Workpiece mounting seat; 7. Annular flat washer; 8. Pressing head; 9. Workpiece to be processed; 10. Connecting shaft; 11. Bearing. Detailed Implementation

[0036] To make the objectives, advantages and features of this utility model clearer, the following describes in further detail a pneumatic clamping device proposed by this utility model in conjunction with the accompanying drawings and specific embodiments.

[0037] like Figure 1-4 As shown, this utility model addresses the technical problems of low machining accuracy and limited air circuit connection caused by the rotation of the pneumatic clamp with the workpiece in current related pneumatic fixtures. It designs a pneumatic clamping device, including a mounting base 1, a cylinder 2, a piston 3, a connecting sleeve 4, an upper pressure cover 5, and a workpiece mounting assembly. The workpiece mounting assembly includes a workpiece mounting seat 6 and a clamping head 8.

[0038] The bottom of cylinder 2 is a frustum, and the top is a cylindrical part coaxially connected to the frustum, with the diameter of the cylindrical part being smaller than that of the frustum. A piston 3 is installed inside the frustum, dividing the interior of the frustum into an upper chamber and a lower chamber. The cylindrical part has a first through hole, a first air inlet / outlet passage, and a second air inlet / outlet passage. The first air inlet / outlet passage and the second air inlet / outlet passage respectively include a first air passage and a second air passage arranged axially along the cylindrical part, and a first air channel and a second air channel arranged radially along it. The lower end of the first air passage is connected to the upper chamber, and the upper end is connected to the first air channel. The lower end of the second air passage is connected to the lower chamber through a third air passage, and the upper end is connected to the second air channel. The first annular groove 201 and the second annular groove 202 are located at the outer ends of the first air channel and the second air channel, respectively. The end faces of the first annular groove and the second annular groove are arc-shaped.

[0039] The third air passage includes a third air channel arranged radially along the frustum portion and a fourth air channel arranged axially along the frustum portion, and the third air channel and the fourth air channel are connected. The lower end of the second air passage is connected to the third air channel, and the lower end of the fourth air channel is connected to the lower chamber.

[0040] On the connecting sleeve 4, sealing grooves 401 are respectively provided on both sides corresponding to the positions of the first annular air groove 201 and the second annular air groove 202. O-rings are provided in the sealing grooves to increase the sealing performance of the entire air circuit and ensure pressure stability.

[0041] The connecting sleeve 4 is fitted onto the cylindrical part, and both ends of the sleeve have recesses. A bearing 11 is installed in each of the two recesses. The outer ring of the bearing 11 is interference-fitted with the connecting sleeve 4, and the inner ring of the bearing 11 is interference-fitted with the outer wall of the cylindrical part, allowing the cylindrical part to rotate relative to the connecting sleeve 4. A first air hole and a second air hole are provided radially along the connecting sleeve 4. The outer ends of both the first and second air holes are connected to an external air source, and their inner ends are respectively connected to the first annular air groove 201 and the second annular air groove 202. The cylinder 2 and piston 3 form a complete pneumatic structure. The piston 3 divides the cylinder 2 into an upper chamber and a lower chamber. The first and second air inlet / outlet passages are both located on the cylinder 2 and on the upper and lower sides of the piston 3, respectively. Compressed gas enters the upper or lower chamber, pushing the piston up / down. A first annular groove 201 and a second annular groove 202 are provided on the outer wall of the cylindrical part of cylinder 2. At the moment of air intake, the first annular groove 201 and the second annular groove 202 will form a small pressure vessel, reducing the large impact force brought by the instantaneous intake of compressed gas, increasing the overall strength and pressure resistance of the pneumatic clamping device structure, improving the stability of the pneumatic clamping device, and thus ensuring the pressing accuracy of the workpiece to be processed. In addition, the air source is connected to the outer wall of the connecting sleeve 4 and does not rotate with the workpiece to be processed, so that the air circuit connection is not restricted.

[0042] The upper pressure cover 5 has an annular boss on the side near the bearing 11 that matches the inner ring size of the bearing 11. The connection between the cylindrical and frustum portions has an annular limiting step that matches the inner ring size of the bearing 11. The upper pressure cover 5 connects to the top surface of the cylindrical portion, so that the inner rings of the two bearings 11 are clamped and limited by the annular boss and the annular limiting step, leaving a gap between the lower end of the connecting sleeve 4 and the frustum portion. The bearing 11 is a deep groove ball bearing. Deep groove ball bearings have high rotational speed, small radial clearance, and can withstand increased radial and axial loads, further improving the accuracy and stability of the pneumatic clamping device. Furthermore, the connecting sleeve 4 and the cylinder 2 are supported by double bearings 11, reducing the impact force on the workpiece during the air intake process, thus weakening the impact of the air intake process on the workpiece. The high rotational speed, small radial clearance, and ability to withstand large radial and axial loads of the bearing 11 further improve the accuracy and stability of the pneumatic clamping device.

[0043] A workpiece mounting seat 6 is installed on the top of the upper pressure cover 5. The end of the workpiece mounting seat 6 furthest from the upper pressure cover 5 has a workpiece mounting position. The small end of the clamping head 8 passes through a through hole at the axis of the workpiece mounting seat 6 and is connected to the piston 3. An annular flat washer 7 is fitted on the small end of the clamping head 8 to lock and release the workpiece 9 to be processed mounted on the workpiece mounting seat 6. The annular flat washer 7 has a mounting notch. Defined as follows: if the diameter of the small end of the clamping head 8 is D1, and the maximum opening distance of the mounting notch is D2, then D1≤D2≤1.3D1. Preferably, D1=D2. The high planar accuracy of the annular flat washer 7 ensures that the workpiece to be processed will not be tilted under pressure, effectively avoiding deformation or movement of the workpiece caused by uneven force.

[0044] The mounting base 1 is connected to the bottom surface of the frustum, and the mounting base 1 has a guide channel on the side near the cylinder 2. Let the height of the mounting base 1 be h1, and the height of the frustum be h2. Then, 0.8h2≤h1≤1.1h2. Designing the mounting base 1 to be approximately the same height as the frustum is beneficial for machining stability, as the height of the machining tool is limited. Increasing the height of the mounting base while decreasing the height of the frustum improves machining stability.

[0045] The piston 3 has a first guide post 301 and a second guide post 302 at both ends, threaded holes penetrating the first guide post 301 and the second guide post 302, and annular grooves on the upper and lower end faces of the piston 3. The first guide post 301 is located in the first through hole, and the second guide post 302 is located in the guide channel. The small end of the clamping head 8 is connected to the first guide post 301 via a connecting shaft 10. The first guide post 301 and the second guide post 302 are provided on the piston 3, and the through threaded holes can accommodate part of the unused connecting shaft, increasing the adjustment range of the connecting shaft and enabling the clamping head to clamp workpieces of different heights.

[0046] In operation, compressed air enters through the second air hole and then through the second inlet / outlet passage into the lower chamber. Under the action of the compressed air, piston 3 moves upward, and connecting shaft 10 drives clamping head 8 to move upward together, installing the workpiece to be processed and installing the annular flat washer 7. After installation, the compressed air in the lower chamber is discharged, and compressed air enters through the first air hole and through the first inlet / outlet passage into the upper chamber. Under the action of the compressed air, piston 3 moves downward, and the annular flat washer 7 clamps the workpiece to be processed, completing the clamping operation of the workpiece.

[0047] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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; 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 based on the specific circumstances.

[0048] In the description of this utility model, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this utility model.

Claims

1. A pneumatic clamping device, characterized in that: Includes cylinder (2), piston (3), connecting sleeve (4), upper pressure cover (5) and workpiece mounting assembly; The bottom of the cylinder (2) is a frustum, and the top is a cylindrical part coaxially connected to the frustum, and the diameter of the cylindrical part is smaller than the diameter of the frustum. The piston (3) is provided inside the frustum section, and the interior of the frustum section is divided into an upper chamber and a lower chamber; The cylindrical part has a first through hole, a first air inlet / outlet passage and a second air inlet / outlet passage, and a first annular air groove (201) and a second annular air groove (202) are provided on the outer wall of the cylindrical part along the circumferential direction; the first ends of the first air inlet / outlet passage and the second air inlet / outlet passage are respectively connected to the upper chamber and the lower chamber, and the second ends are respectively connected to the first annular air groove (201) and the second annular air groove (202); The connecting sleeve (4) is fitted onto the cylindrical part, and both ends of the sleeve have countersunk platforms. Each countersunk platform is equipped with a bearing (11). The outer rings of the two bearings (11) are interference-fitted with the connecting sleeve (4), and the inner rings are interference-fitted with the outer wall of the cylindrical part, so that the cylindrical part can rotate relative to the connecting sleeve (4). The inner wall of the connecting sleeve (4) and the outer wall of the cylindrical part are sealed. The connecting sleeve (4) has a first air hole and a second air hole in the radial direction. The outer ends of the first air hole and the second air hole are connected to an external air source, and their inner ends are respectively connected to the first annular air groove (201) and the second annular air groove (202). The upper pressure cap (5) is connected to the top surface of the cylindrical part so that the inner rings of the two bearings (11) are pressed between the upper pressure cap (5) and the frustum part; a gap is left between the lower end of the connecting sleeve (4) and the frustum part. The workpiece mounting assembly is mounted on the top of the upper pressure cover (5). The workpiece mounting assembly includes a clamping head (8). The small end of the clamping head (8) passes through the first through hole and is connected to the piston (3) so as to lock and release the workpiece (9) to be processed mounted on the workpiece mounting assembly.

2. The pneumatic clamping device according to claim 1, characterized in that: The first air inlet / outlet passage and the second air inlet / outlet passage respectively include a first air passage and a second air passage arranged along the axial direction of the cylindrical portion, and a first air channel and a second air channel arranged along its radial direction. The lower end of the first air passage is connected to the upper chamber, and the upper end is connected to the first air channel. The lower end of the second air passage is connected to the lower chamber through a third air passage, and the upper end is connected to the second air channel. The first annular air groove (201) and the second annular air groove (202) are located at the outer ends of the first air channel and the second air channel, respectively. The third air passage includes a third air channel arranged radially along the frustum portion and a fourth air channel arranged axially along the frustum portion, and the third air channel and the fourth air channel are connected. The lower end of the second air passage is connected to the third air channel, and the lower end of the fourth air channel is connected to the lower chamber.

3. The pneumatic clamping device according to claim 1, characterized in that: The upper pressure cover (5) has an annular boss on the side near the bearing (11) that corresponds to the inner ring of the bearing (11). The connection between the cylindrical part and the frustum part has an annular limiting step that corresponds to the inner ring of the bearing (11). The upper pressure cover (5) is connected to the top surface of the cylindrical part so that the inner rings of the two bearings (11) are clamped and limited by the annular boss and the annular limiting step.

4. The pneumatic clamping device according to claim 1, characterized in that: The workpiece mounting assembly also includes a workpiece mounting base (6), one end of which is connected to the upper pressure cover (5), and the other end has a workpiece mounting position. The small end of the clamping head (8) passes through the through hole at the axis of the workpiece mounting base (6), and an annular flat washer (7) is fitted on the small end of the clamping head (8).

5. The pneumatic clamping device according to claim 4, characterized in that, The annular flat pad (7) has an installation notch. Defined as follows: the diameter of the small end of the pressing head (8) is D1, and the maximum opening distance of the installation notch is D2. Then D1≤D2≤1.3D1.

6. The pneumatic clamping device according to any one of claims 1-5, characterized in that: It also includes a mounting base (1), which is connected to the bottom surface of the frustum, and the mounting base (1) has a guide channel on the side near the cylinder (2); The piston (3) has a first guide post (301) and a second guide post (302) at its two ends respectively. The first guide post (301) is located in the first through hole, and the second guide post (302) is located in the guide channel. The small end of the pressing head (8) is connected to the first guide post (301).

7. The pneumatic clamping device according to claim 6, characterized in that: It also includes a connecting shaft (10), the small end of the pressing head (8) being connected to the first guide post (301) via the connecting shaft (10).

8. The pneumatic clamping device according to claim 7, characterized in that: The piston (3) has a threaded hole that passes through the first guide post (301) and the second guide post (302). The lower end of the connecting shaft (10) is located in the threaded hole, and the other end is connected to the small end of the pressing head (8).

9. The pneumatic clamping device according to claim 8, characterized in that: Define the height of the mounting base (1) as h1 and the height of the frustum as h2, then 0.8h2≤h1≤1.1h2.

10. The pneumatic clamping device according to claim 6, characterized in that: The piston (3) is provided with annular protrusions on both its upper and lower end faces, and the two annular protrusions are located on the periphery of the first guide post (301) and the second guide post (302), respectively.

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