Internal expansion clamp

Abstract

An internal expansion clamp includes an oil cylinder and a rocker mechanism. A reciprocating drive structure is provided at the top of the piston rod of the oil cylinder and is used to drive the rocker to rotate. A workpiece positioning plate is provided on the piston rod and is coaxially arranged with the piston rod. At least three positioning claws are provided on the workpiece positioning plate to limit the outer ring of the workpiece. The rocker mechanism includes a rocker and a rocker fixing plate. An even number of rocker support members are provided on the fixing plate. The rocker support members pass through the through holes on the workpiece positioning plate. There are at least three rockers. The rockers are pivotally connected to the rocker support members through a pin provided in the middle of the rocker. The inner end of the rocker reciprocates with the reciprocating drive structure. The invention has the advantages of a large adjustable range of expansion size, good concentricity with the workpiece, good clamping state, and is suitable for use with workpieces of different outer diameters.

Description

Technical Field

[0001] The invention relates to the technical field of clamps, in particular to an internal expansion clamp with a large adjustable expansion size range and good concentricity. Background Art

[0002] The existing internal expansion clamp generally includes an internal expansion body and an external expansion cone. The internal expansion body is sleeved in the external expansion cone. The internal expansion body is pressurized by external force to expand the claw-shaped external expansion cone. The outer surface of the external expansion cone is in close contact with the inner surface of the workpiece to achieve the purpose of expanding the workpiece. Due to structural design problems, the existing internal expansion clamp has the following problems: first, due to the limitation of the internal expansion body structure, the adjustable range of the expansion size of the external expansion body is very small, generally only adjustable within 1mm; second, there is a deviation between the inner diameter of the internal expansion body, the external expansion cone and the workpiece, and the deviation is difficult to adjust; third, the expansion of the workpiece and the internal expansion clamp is achieved by the mutual expansion of the outer surface of the external expansion cone and the inner surface of the workpiece, which has poor stability and may cause slippage. Summary of the invention

[0003] In order to overcome the above problems, the invention provides the society with an internal expansion clamp with a large adjustable range of expansion size.

[0004] The invention also has the advantage of good concentricity between the clamp and the workpiece.

[0005] The present invention also has the advantage of good clamping state.

[0006] The technical solution of the invention is: to provide an internal expansion clamp, including a cylinder and a rocker mechanism, a reciprocating drive structure is provided at the top end of the piston rod of the cylinder and is used to drive the rocker to rotate, and the piston rod is sleeved with a workpiece positioning plate coaxially arranged with the piston rod, and at least three positioning claws for limiting the outer ring of the workpiece are provided on the workpiece positioning plate; the rocker mechanism includes a rocker and a rocker fixing plate, an even number of rocker support members are provided on the fixing plate, and the rocker support members pass through the through holes on the workpiece positioning plate; there are at least 3 rockers, and the rocker is pivotally connected to the rocker support member through a pin shaft provided in the middle of the rocker, and the inner end of the rocker reciprocates with the reciprocating drive structure.

[0007] As an improvement to the present invention, the reciprocating drive structure includes a first conical body and a second conical body, the first conical body is arranged on the top end of the piston rod, the first small end face of the first conical body is oriented toward the end away from the cylinder, the second conical body is connected to the top end by screws, the second small end face of the second conical body is arranged opposite to the small end face of the first conical body, an annular groove is formed between the first small end face of the first conical body and the small end face of the second conical body, and the inner end of the rocker arm extends into the annular groove.

[0008] As an improvement to the present invention, the positioning claw is movably connected to the workpiece positioning plate to adjust the size of the inner circle of the circle where the positioning claw is located.

[0009] As an improvement to the present invention, the positioning claw is an independent component, and the positioning claw includes a clamping portion and a connecting portion, the width of the clamping portion is smaller than the width of the connecting portion, and a receiving groove for accommodating the connecting portion is provided on the circumference of the workpiece positioning disk, and the positioning claw is slidably connected to the receiving groove; a positioning screw is provided at the bottom of the receiving groove, and a limit member is provided in the receiving groove, and the limit member is fixed to the side of the workpiece positioning disk relative to the receiving groove by a fastener, and an adjustment screw for adjusting the positioning claw is provided on the limiting member.

[0010] As an improvement to the present invention, the present invention further comprises a flange, and the flange is connected to the cylinder body of the oil cylinder.

[0011] As an improvement to the present invention, an inwardly inclined inclined surface for guiding the workpiece is provided on the inner wall surface of the positioning claw.

[0012] As an improvement to the present invention, the first frustum and / or the second frustum may be replaced by a cone.

[0013] The invention has the advantages of a large adjustable range of expansion size, good concentricity with the workpiece, good clamping state, and is suitable for use with workpieces of different outer diameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the decomposed structure of an embodiment of the present invention.

[0015] Figure 2 yes Figure 1 Schematic diagram of the assembled structure with the pendulum open.

[0016] Figure 3 yes Figure 1 Schematic diagram of the assembled structure with the rocker arm closed.

[0017] Figure 4 yes Figure 3 Schematic diagram of the main view plane structure.

[0018] Figure 5 yes Figure 4 Schematic diagram of the AA cross-sectional structure.

[0019] Figure 6 It is a structural schematic diagram of another clamp assembly in the present invention.

[0020] Figure 7 It is a schematic diagram of the use state when the inner circle of the workpiece in the present invention is relatively large. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the invention more clearly understood, the invention is described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention and are not used to limit the invention.

[0022] See also Figures 1 to 5 , Figures 1 to 5 The invention discloses an internal expansion clamp, comprising an oil cylinder 1 and a rocker mechanism 2, wherein a reciprocating driving structure 12 is provided at the top end 111 of a piston rod 11 of the oil cylinder 1 and is used to drive a rocker 21 to rotate. A workpiece positioning plate 13 is provided on the piston rod 11 near the top end 111 and is coaxially arranged with the piston rod 11. At least three uniformly arranged positioning claws 131 are provided on the workpiece positioning plate 13 for defining the outer ring of a workpiece 4. The rocker mechanism 2 comprises a rocker 21 and a rocker fixing plate 22. An even number of swing rod support members 221 are provided, and a pair of swing rod support members 221 is used to set a swing rod 21, and the swing rod support member 221 passes through the through hole 132 on the workpiece positioning plate 13; the number of the swing rods 21 is at least 3, and in this embodiment, there are 4. Of course, there can also be more than 3. Due to space limitations, the number of the swing rods 21 should not be too many, and 3 or 4 are preferred. The swing rod 21 is pivotally connected to the swing rod support member 221 through a pin 211 provided in the middle of the swing rod 21, and the inner end 212 of the swing rod 21 reciprocates with the reciprocating drive structure 12. In this embodiment, the side surface of the inner end 212 of the swing rod 21 is formed by a smooth transition of an arc surface, so as to facilitate the coordinated movement with the reciprocating drive structure 12.

[0023] Preferably, the reciprocating drive structure 12 includes a first conical body 121 and a second conical body 122, the first conical body 121 being arranged on the top end 111 of the piston rod 11, the first small end face 1211 of the first conical body 121 being oriented toward an end away from the oil cylinder 1, the second conical body 122 being connected to the top end 111 by a screw 123, the second small end face 1221 of the second conical body 122 being arranged opposite to the small end face of the first conical body 121, an annular groove 124 being formed between the first small end face 1211 of the first conical body 121 and the small end face 1221 of the second conical body 122, and the inner end 212 of the rocker arm 21 extending into the annular groove 124.

[0024] When in use, first fix the oil cylinder 1 on the fixing seat 5 through the flange 14. The fixing seat 5 in the present invention is a CNC four-axis. It should be noted that in the present invention, only the CNC four-axis is used as an example for explanation, but the present invention includes but is not limited to the CNC four-axis. Any base that can fix the oil cylinder is acceptable. In this embodiment, the oil cylinder 1 is arranged horizontally. The oil cylinder 1 can also be arranged vertically or obliquely according to needs. The workpiece positioning plate 13 is fixedly connected to the other side of the fixing seat 5, or is fixedly connected to the fixing seat 5 through a turntable 51. In this embodiment, the turntable 51 is a four-axis turntable; when When it is necessary to clamp the workpiece 4, the piston rod 11 is pushed outward, the first frustum 121 pushes the inner end 212 of the rocker arm 21 to rotate outward, and the outer end 213 of the rocker arm 21 rotates in the opposite direction to press the workpiece 4. When the workpiece 4 is clamped, no relative sliding occurs between the workpiece 4 and the fixture. When in use, the inner diameter of the workpiece 4 only needs to be larger than the outer diameter of the circle where the rocker arm support 221 is located and smaller than the inner diameter of the circle where the positioning claw 131 is located by a predetermined distance. This distance only needs to ensure that the rocker arm 21 can press the workpiece, which can greatly expand the expansion size of the workpiece 4. The present invention can be adjusted within the range of 0.1-100mm.

[0025] Preferably, the present invention further comprises a flange 14 , and the flange 14 is connected to the cylinder body of the oil cylinder 1 .

[0026] Preferably, an inwardly inclined inclined surface 1313 for guiding the workpiece is provided on the inner wall surface of the positioning claw 131 .

[0027] Preferably, the first frustum body 121 and / or the second frustum body 122 may be replaced by a cone.

[0028] See also Figure 6 The positioning claw 131 is movably connected to the workpiece positioning disk 13, and is used to adjust the size of the inner circle of the circle where the positioning claw 131 is located. Specifically, the positioning claw 131 is an independent component, and the positioning claw 131 includes a clamping portion 1311 and a connecting portion 1312. The width of the clamping portion 1311 is smaller than the width of the connecting portion 1312. A receiving groove 133 for receiving the connecting portion 1312 is provided on the circumference of the workpiece positioning disk 13, and the positioning claw 131 is slidably connected to the receiving groove 133; a positioning screw 1331 is provided at the bottom of the receiving groove 133, and the positioning screw 1331 is provided in a screw hole 1332. A limiting member 134 is provided in the receiving groove 133, and the limiting member 134 is fixed to the side of the workpiece positioning disk 13 relative to the receiving groove 133 by a fastener 1341. An adjusting screw 1342 for adjusting the positioning claw 131 is provided in the limiting member 134. The structure of the movable positioning claw 131 can be suitable for use with workpieces of different outer diameters.

[0029] Preferably, the present invention further comprises a first copper sleeve 61 and / or a second copper sleeve 62, wherein the first copper sleeve 61 and / or the second copper sleeve 62 is sleeved on the piston rod 11 and located on the side of the fixing seat 5 to ensure the concentricity of the piston rod 11 and the fixing seat 5; the positioning claw 131 is used to first position the outer ring of the workpiece on the pre-adjusting table to ensure the concentricity of the workpiece 4 and the piston rod 11, so that the piston rod 11, the fixing seat 5 and the workpiece 4 are completely concentric.

[0030] See also Figure 7 , Figure 7 The inner ring of the workpiece of the embodiment shown is Figure 5 Compared with the inner ring of the workpiece of the embodiment shown, Figure 7 The inner ring 63 of the workpiece of the illustrated embodiment is larger than Figure 5 The inner ring of the workpiece in the illustrated embodiment illustrates that the present invention is suitable for use in workpieces with different inner diameters.

[0031] Without departing from the concept of the invention, all equivalent changes made by applying the contents of the invention description and drawings are considered to be included in the scope of the claims of the invention.

Claims

1. An internal expansion clamp, characterized in that: The invention comprises an oil cylinder (1) and a rocker mechanism (2); a reciprocating drive structure (12) which moves with the piston rod (11) and is used to drive the rocker (21) to rotate is provided at the top end (111) of the piston rod (11) of the oil cylinder (1); a workpiece positioning plate (13) which is coaxially arranged with the piston rod (11) is sleeved on the piston rod (11); at least three positioning claws (131) for defining the outer ring of the workpiece are provided on the workpiece positioning plate (13); the rocker mechanism (2) comprises a rocker (21) and a rocker fixing plate (22); an even number of rocker support members (221) are provided on the rocker fixing plate (22); a pair of rocker support members (221) are provided on the rocker fixing plate (22); 1) used to set a swing rod (21), the swing rod support member (221) passes through the through hole (132) on the workpiece positioning disk (13); there are at least three swing rods (21), the swing rod (21) is pivotally connected to the swing rod support member (221) via a pin shaft (211) provided in the middle of the swing rod (21), and the inner end (212) of the swing rod (21) reciprocates with the reciprocating drive structure (12); the oil cylinder (1) is fixed to one side of the fixed seat (5), and the workpiece positioning disk (13) is fixedly connected to the other side of the fixed seat (5) via a turntable (51); the fixed seat (5) is a CNC four-axis, and the turntable (51) is a four-axis turntable; The reciprocating drive structure (12) comprises a first truncated cone (121) and a second truncated cone (122); the first truncated cone (121) is arranged on the top end (111) of the piston rod (11); a first small end surface (1211) of the first truncated cone (121) is oriented toward an end away from the oil cylinder (1); the second truncated cone (122) is connected to the top end (111) via a screw (123); a first small end surface (1211) of the first truncated cone (121) is disposed on the top end (111) of the piston rod (11); The two small end faces (1221) are arranged opposite to the small end face of the first truncated cone (121); an annular groove is formed between the first small end face (1211) of the first truncated cone (121) and the small end face (1221) of the second truncated cone (122); the inner end (212) of the swing rod (21) extends into the annular groove; the positioning claw (131) is movably connected to the workpiece positioning plate (13) for adjusting the size of the inner circle of the circle where the positioning claw (131) is located.

2. The internal expansion clamp according to claim 1, characterized in that: The positioning claw (131) is an independent component. The positioning claw (131) comprises a clamping portion (1311) and a connecting portion (1312). The width of the clamping portion (1311) is smaller than the width of the connecting portion (1312). A receiving groove (133) for receiving the connecting portion (1312) is provided on the circumference of the workpiece positioning disk (13). The positioning claw (131) is slidably connected to the receiving groove (133). A positioning screw (1331) is provided at the bottom of the receiving groove (133). A limiting member (134) is provided in the receiving groove (133). The limiting member (134) is fixed to the side of the workpiece positioning disk (13) relative to the receiving groove (133) by a fastener (1341). An adjusting screw (1342) for adjusting the positioning claw (131) is provided in the limiting member (134).

3. The internal expansion clamp according to claim 1 or 2, characterized in that: It also comprises a flange (14), wherein the flange (14) is connected to the cylinder body of the oil cylinder (1).

4. The internal expansion clamp according to claim 1 or 2, characterized in that: An inwardly inclined inclined surface (1313) for guiding a workpiece is provided on the inner wall surface of the positioning claw (131).

5. The internal expansion clamp according to claim 1 or 2, characterized in that: The first frustum (121) and / or the second frustum (122) may be replaced by a cone.

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