CN111266903B

CN111266903B - Clamp

Info

Publication number: CN111266903B
Application number: CN202010243164.2A
Authority: CN
Inventors: 张涛; 葛建伟; 高兆春; 殷伟
Original assignee: Zhejiang Headman Intelligent Equipment Co ltd
Current assignee: Zhejiang Headman Intelligent Equipment Co ltd
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2024-07-09
Anticipated expiration: 2040-03-31
Also published as: CN111266903A

Abstract

The invention provides a clamp, and belongs to the technical field of clamps. The clamping device solves the problem that the thin-wall annular part is easy to deform during clamping. The clamping assembly is provided with a first clamping part which is cylindrical and elastic, the clamping assembly is also provided with a second clamping part which is cylindrical and elastic, the clamping part is positioned on the first inner side of the clamping part, an annular mounting channel is arranged between the clamping part and the first clamping part, conical surface contact is formed between the clamping part and the second clamping part and the base, and when the connecting plate slides along the central axis direction, the clamping part and the clamping part are mutually close through the conical surface contact. The device has the advantages of high processing precision, difficult deformation of parts, simple structure, low cost and the like.

Description

Clamp

Technical Field

The invention belongs to the technical field of clamps and relates to a clamp.

Background

When the end face of the thin-wall annular part is used for machining holes or grooves, the thin-wall annular part is unsuitable for clamping by adopting a conventional main shaft clamp because the thin-wall annular part is weak in structural strength. At present, a relatively common clamping mode is to realize clamping through a surface-to-surface contact mode, for example, a numerical control lathe clamp with the application number 201410441910.3 disclosed in China patent publication comprises a clamp seat, a main body, a spring chuck, a pull ring, a supporting seat, a conical sleeve, a positioning cylinder seat, a pull rod head, a clamping block and a positioning cylinder, wherein the clamp seat is fixed on a main shaft, the front end of the main body is fixedly connected with the clamp seat, the supporting seat is positioned in the main body, the front end of the supporting seat is fixed on the clamp seat, the positioning cylinder seat is fixed on the rear end surface of the supporting seat, the positioning cylinder is fixed on the rear end surface of the supporting seat, an annular groove is formed in the inner wall of the rear end of the main body, a conical sleeve is arranged in the annular groove, the inner wall of the conical sleeve is a conical surface, the spring chuck is arranged in the main body and is positioned between the main body and the supporting seat, the outer wall of the rear end of the spring chuck is provided with a conical surface matched and contacted with the conical surface of the inner wall of the conical sleeve, the clamping block is fixed on the inner wall of the rear end of the spring chuck, the pull ring is fixed on the pull rod head, the pull ring is fixedly connected with the clamping cylinder of the spring chuck through the pull rod. The spring chuck is driven to shrink inwards in a conical surface matching mode when the pull ring moves, so that the spring chuck is clamped on the peripheral surface of the annular part to prevent deformation of the annular part.

However, in the actual production process, it is found that, because the thin-walled annular part has a very thin wall thickness, when the collet chuck is clamped on the outer peripheral surface of the part, the part is easy to deform due to the clamping force exerted on a single side because of no support on the inner side of the part, so that the perpendicularity between the end surface of the part to be machined and the clamping surface is poor, and thus the machined end surface of the part cannot be kept perpendicular to the feeding direction of the cutter, and the machining precision is poor.

In addition to this, there is a type of clamp that clamps the inner peripheral surface of a ring-shaped part to achieve clamping, for example, a machine tool clamp disclosed in application No. 200710134795.5 that can process a thin-walled workpiece of a revolving body, but in this manner, a situation that the part is deformed due to unilateral stress occurs.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a clamp which solves the problem that a thin-wall annular part is easy to deform during clamping.

The aim of the invention can be achieved by the following technical scheme:

The clamp comprises a base, wherein a connecting plate is arranged in the base in a sliding manner along the direction of a central axis, and a clamping assembly in linkage relation with the connecting plate is arranged on the clamping assembly, and a clamping part I which is cylindrical and elastic is arranged on the clamping assembly.

The fixture is mainly used when the end face of the thin-wall annular part is machined, the base is fixed on the main shaft of the numerical control lathe, the central line direction of the base and the axial direction of the main shaft are in the same direction, and therefore the sliding direction of the connecting plate and the axial direction of the main shaft can be ensured to be in the same direction, and the cylinder piston rod in the main shaft of the numerical control lathe is fixed with the connecting plate. The staff places the annular part of thin wall class in the annular installation passageway between clamping part one and clamping part two, then controls the work of the hydro-cylinder of taking certainly in the numerical control lathe main shaft, and the piston rod of hydro-cylinder pulls the connecting plate to keeping away from the cavity direction, and the clamping component is linked along with the connecting plate and makes clamping part one inwards shrink under the conical surface effect and makes clamping part two outwards expand under the conical surface effect, namely clamping part one and clamping part two are close to each other. Thus, the first clamping part is clamped on the outer peripheral surface of the thin-wall annular part, and the second clamping part is clamped on the inner peripheral surface of the thin-wall annular part, so that the inner and outer clamping is realized.

Through the setting of clamping part one and clamping part two, formed the inside and outside clamp to thin wall class annular part, the unilateral atress's condition can not appear in thin wall department of thin wall class annular part like this, utilizes inside and outside clamp to form the balance promptly for thin wall class annular part can not warp when the centre gripping, has ensured that the terminal surface of thin wall class annular part can keep better straightness with the clamping face after the centre gripping, thereby guarantees machining precision and the quality of product. In the clamp, the clamping action of the clamping assembly is formed along with the linkage of the connecting plate, and the connecting plate is directly driven by the existing oil cylinder in the main shaft of the numerically controlled lathe without driving by other driving sources or modes, so that the structure is simpler and the cost is lower. Moreover, the mutual approaching of the first clamping part and the second clamping part can be realized at the same time only through one action of the oil cylinder, and the clamping efficiency is improved well.

In the above-mentioned fixture, the first clamping part comprises a plurality of first clamping petals, the second clamping part comprises a plurality of second clamping petals, the outer side wall of each first clamping petal is in conical surface contact with the base, and the inner side wall of each second clamping petal is in conical surface contact with the base.

When the clamping assembly I moves along with the sliding of the connecting plate, each clamping flap I is clamped inwards under the action of the conical surface, and each clamping flap II is tensioned outwards under the action of the conical surface, so that the inner and outer clamping of the thin-wall annular part is formed to prevent the deformation of the thin-wall annular part.

In the fixture, the base comprises a base body with a concave cavity at one end and a guide component arranged in the concave cavity, the clamping component is arranged in the concave cavity, the first clamping petals are matched with the inner wall of the mouth of the concave cavity, and the guide component is positioned on the inner side of the second clamping petals and can enable the two end parts of the second clamping petals to be outwards tensioned when the connecting plate slides.

When the connecting plate slides, one end part of each clamping flap is clamped inwards under the action of the inner wall of the mouth part of the concave cavity, and the two end parts of each clamping flap are tensioned outwards under the action of the guide component. By means of the arrangement of the inner wall of the opening of the concave cavity and the guide component, the actions of the first clamping valve and the second clamping valve when the connecting plate slides can be mutually not interfered, and the reliability of clamping the inner and outer surfaces of the thin-wall annular part to prevent the deformation of the thin-wall annular part is ensured.

In the clamp, the second clamping petals are fixed on the bottom wall of the concave cavity, the guide assembly comprises a positioning rod fixed at the center of the bottom wall of the concave cavity and a guide core sleeved outside the positioning rod, the guide core is in conical surface contact with the second clamping petals, a spring is sleeved on the positioning rod, a blocking piece extending into the concave cavity is arranged on the connecting plate, and the guide core abuts against the blocking piece under the action of the elastic force of the spring.

In the initial state, the guide core is abutted against the blocking piece and cannot move. When the connecting plate moves, the blocking piece is separated from the guide core to lose the blocking effect on the guide core, and the guide core moves in the same direction with the connecting plate under the action of the elastic force of the spring, so that the guide core can automatically and outwards tighten the end part of each second clamping valve on the inner peripheral surface of the thin-wall annular part under the action of the conical surface; when the connecting plate returns, the blocking piece is propped against the guide core to overcome the elastic force of the spring and synchronously return.

By the arrangement mode, a linkage relation is formed between the guide core and the connecting plate, and the outward tensioning of the two end parts of each clamping flap can be synchronously realized when the clamping flaps are clamped inwards under the action of the inner wall of the mouth part of the concave cavity, so that deformation of the thin-wall annular part during clamping is prevented.

In the above-mentioned fixture, as another technical scheme, each second clamping piece is fixed on the bottom wall of the concave cavity, the guiding component comprises a guiding core and a plurality of pull rods penetrating through the bottom wall of the concave cavity to fix the guiding core with the connecting plate, and the guiding core is in conical surface contact with each second clamping piece.

In the clamp, the clamping valve comprises a second arc-shaped sheet body and a second arc-shaped block body fixedly connected to the two end parts of the arc-shaped sheet body, the clamping assembly comprises a second annular supporting block fixed on the bottom wall of the concave cavity, each second arc-shaped sheet body is fixedly connected to the second annular supporting block along the circumferential direction, and the guide core is in clearance fit with the second annular supporting block.

The second clamping valve and the second annular supporting block are combined into a structure similar to an elastic chuck, so that the second clamping valve can be conveniently fixed in the concave cavity, and meanwhile, when the guide core moves, the second arc-shaped block can be outwards tensioned on the inner peripheral wall of the thin-wall annular part by means of elasticity.

In the clamp, the clamping valve I comprises an arc-shaped sheet body I and arc-shaped block I fixedly connected to one end of the arc-shaped sheet body, the clamping assembly further comprises annular supporting blocks I which are arranged in the concave cavity in a sliding mode, the arc-shaped sheet bodies I are fixedly connected to the annular block I along the circumferential direction, and the connecting plate and the annular supporting blocks I are fixed through a plurality of fastening pieces I penetrating through the bottom wall of the concave cavity.

The first clamping valve and the first annular supporting block are also combined into a structure similar to an elastic chuck, the first annular supporting block and the connecting plate are fixed together through the first fastening piece, and when the connecting plate slides, the first clamping valve can be driven to move through the first annular supporting block, so that the first arc-shaped blocks are contracted inwards and clamped on the peripheral wall of the thin-wall annular part under the action of the inner wall of the opening of the concave cavity.

In the clamp, an annular positioning block is arranged outside the clamping part, a plurality of second fasteners are fixedly connected to the bottom wall of the concave cavity, the positioning block is fixed to each second fastener, an annular flange is arranged at the edge of one end face of the positioning block, facing the mouth of the concave cavity, of the positioning block, and the end part of the annular flange is positioned between each first arc-shaped block and each second arc-shaped block.

When the thin-wall annular part is put into the mounting channel, the thin-wall annular part can be abutted against the end face of the annular flange, and therefore the thin-wall annular part is just positioned between each first arc-shaped block and each second arc-shaped block, and accordingly the first clamping part and the second clamping part can accurately clamp the thin-wall annular part to prevent deformation caused by unilateral stress.

In the fixture, the first annular supporting block is positioned between the positioning block and the bottom wall of the concave cavity, the second fastening piece comprises a fixing sleeve penetrating through the first annular supporting block and a second fastening screw penetrating through the positioning block and the fixing sleeve in sequence and being in threaded connection with the bottom wall of the concave cavity, and two ends of the fixing sleeve are respectively abutted against the positioning block and the bottom wall of the concave cavity.

The annular support block I is arranged between the positioning block and the bottom wall of the concave cavity, so that the whole structure is more compact, and the volume of the whole clamp is not increased. The second fastening piece comprises a fixing sleeve and a second fastening screw, the fixing sleeve penetrates through the first annular supporting block, the second fastening screw sequentially penetrates through the positioning block and the fixing sleeve and is in threaded connection with the bottom wall of the concave cavity, normal movement of the first elastic chuck is guaranteed through cooperation of the fixing sleeve and the first annular supporting block, and normal fixation of the positioning block in the concave cavity is guaranteed through cooperation of the second fastening screw and the fixing sleeve.

In the fixture, the inner side of each arc-shaped block is provided with an arc-shaped raised line I, and the outer side of each arc-shaped block is provided with an arc-shaped raised line II.

The first arc-shaped raised strips can be tightly attached to the outer peripheral surface of the thin-wall annular part, and the second arc-shaped raised strips can be tightly attached to the inner peripheral surface of the thin-wall annular part, so that the clamping effect is further improved. Especially when the length of the thin-wall annular part along the base is shorter, the first raised strips and the second raised strips can be respectively attached to the whole peripheral wall and the whole inner peripheral wall of the thin-wall annular part, and deformation of the parts during clamping is ensured to be less likely to occur.

Compared with the prior art, the clamp has the following advantages:

1. The inner and outer clamping of the thin-wall annular part is formed through the actions of the first clamping part and the second clamping part, so that a good supporting effect is achieved, the thin-wall annular part is ensured not to deform during clamping due to unilateral stress, and the machining precision and the quality of products are ensured;

2. the inward contraction of each first clamping valve and the outward tensioning of each second clamping valve can be simultaneously realized through one-time action of the oil cylinder in the main shaft of the numerical control lathe, so that the clamping efficiency is improved well, and the clamping device does not need to be driven by other driving sources or modes, so that the structure is simpler and the cost is lower;

3. the positioning blocks are arranged, so that the clamp can accurately clamp the thin-wall annular parts, and machining precision is guaranteed.

Drawings

Fig. 1 is a schematic perspective view of the fixture and the thin-wall annular part.

Fig. 2 is a cross-sectional view of an embodiment of the present clamp (when a thin-walled annular part is attached).

Fig. 3 is a partial enlarged view of fig. 2.

Fig. 4 is a schematic perspective view of a first elastic chuck in the present clamp.

Fig. 5 is a partially exploded view of the three-dimensional structure of the second collet in the present clamp.

In the figure, 1, a base; 1a, a seat body; 1a1, a cavity; 1a2, annular lugs; 1b, a seat board; 2. a connecting plate; 3. a clamping part I; 3a, clamping a first valve; 3a1, arc sheet body one; 3a2, arc block one; 3a21, first convex strips; 4. a second clamping part; 4a, clamping a second valve; 4a1, an arc-shaped sheet body II; 4a2, arc-shaped blocks II; 4a3, clamping blocks; 4a31, second protruding strips; 5. a mounting channel; 6. a positioning rod; 7. a guide core; 8. a spring; 9. a blocking member; 9a, a guide sleeve; 9b, positioning screws; 10. annular support blocks II; 11. annular support blocks I; 12. a first fastener; 12a, sliding sleeve; 12b, fastening screw one; 13. a positioning block; 13a, an annular flange; 14. a second fastener; 14a, a fixed sleeve; 14b, fastening a second screw; 15. a fixing screw; 16. installing a screw; 17. thin-walled annular parts.

Detailed Description

The following are specific embodiments of the present invention and the technical solutions of the present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

Example 1

As shown in fig. 1 and 2, the fixture comprises a base 1, wherein the base 1 comprises a base body 1a and a seat plate 1b, the base body 1a is in a cylindrical block shape, an installation cavity is formed in one end face of the base body 1a, and a connecting plate 2 is arranged in the installation cavity along the central axis direction of the base body 1a, namely, in an axial sliding manner. The outer peripheral wall of the seat body 1a is provided with an annular lug 1a2, the seat board 1b is connected to an end face of the seat body 1a provided with a mounting cavity, the seat board 1b and the seat body 1a are fixed through a fixing screw 15 penetrating through the annular lug 1a2 and penetrating into the seat board 1b, and the connection of the seat board 1b enables the connecting board 2 to slide in the mounting cavity only without falling out of the mounting cavity. The seat board 1b is in a ring shape, when in use, the seat board 1b is fixed on a main shaft of the numerical control lathe, and a cylinder piston rod in the main shaft of the numerical control lathe is fixed with the connecting board 2 through a central hole of the seat board 1b.

As shown in fig. 1, 2 and 3, the other end face of the seat body 1a is provided with a concave cavity 1a1, a clamping component is arranged in the concave cavity 1a1, and the clamping component and the connecting plate 2 form a linkage relation. Be equipped with clamping part one 3 on the clamping component, be equipped with clamping part two 4 on the clamping component, clamping part one 3 all is the tube-shape and has elasticity with clamping part two 4, and clamping part two 4 are located the inboard of clamping part one 3 and are equipped with annular installation passageway 5 between the two, form conical surface contact between clamping part one 3 and clamping part two 4 all and the base, pass through conical surface contact when connecting plate 2 slides along the central axis direction can make clamping part one 3 and clamping part two 4 be close to each other.

As shown in fig. 2,3 and 4, the first clamping portion 3 includes a plurality of first clamping segments 3a, and an outer sidewall of each first clamping segment 3a is in conical surface contact with the base 1. Each clamping flap one 3a comprises an arc-shaped sheet body one 3a1 and an arc-shaped block one 3a2 fixedly connected to the end part of the arc-shaped sheet body one 3a1, the clamping assembly comprises an annular supporting block one 11 which is arranged in the concave cavity 1a1 in a sliding mode, each arc-shaped sheet body one 3a1 is fixedly connected to the end face, facing the mouth part of the concave cavity 1a1, of the annular supporting block one 11 along the circumferential direction, the connecting plate 2 and the annular supporting block one 11 are fixed through a plurality of fastening pieces one 12 penetrating through the bottom wall of the concave cavity 1a1, and the outer side wall of each arc-shaped block one 3a2 is in conical surface contact with the inner wall of the mouth part of the concave cavity 1a 1. Specifically, each clamping flap one 3a and the annular supporting block one 11 are of an integrated structure, namely, a structure identical to that of the elastic chuck is formed by combining, when the connecting plate 2 moves, each clamping flap one 3a can be driven to move towards the corresponding side through the annular supporting block one 11, and then each arc-shaped block one 3a2 is contracted inwards under the action of the conical surface. The inner side of each arc-shaped block 3a2 is provided with an arc-shaped raised line 3a21.

As shown in fig. 2, in this embodiment, each fastener one 12 includes a sliding sleeve 12a penetrating through the bottom wall of the cavity 1a1 and a fastening screw one 12b penetrating through the annular support block one 11 and the sliding sleeve 12a in sequence and being screwed into the connecting plate 2, and two ends of the sliding sleeve 12a respectively abut against the connecting plate 2 and the annular support block one 11. The first annular support block 11 is abutted against the end of the sliding sleeve 12a, so that a gap is formed between the first annular support block 11 and the bottom wall of the concave cavity 1a1, and the first annular support block 11 can be ensured to slide smoothly in the direction approaching the mounting cavity.

As shown in fig. 2, 3 and 5, the second clamping portion 4 includes a plurality of second clamping flaps 4a, and the inner side wall of each second clamping flap 4a is in conical surface contact with the base 1. The base 1 further comprises a guide component arranged in the concave cavity 1a1, wherein the guide component is positioned at the inner side of each clamping flap 4a and can enable the end part of each clamping flap 4a to be outwards tensioned when the connecting plate 2 slides. Specifically, each second clamping flap 4a comprises a second arc-shaped sheet body 4a1 and a second arc-shaped block body 4a2 fixedly connected to the end part of the second arc-shaped sheet body 4a1, the clamping assembly comprises a second annular supporting block 10 fixed on the bottom wall of the concave cavity 1a1 through a plurality of mounting screws 16, the second annular supporting block 10 is positioned on the inner side of the first annular supporting block 11, and each second arc-shaped sheet body 4a1 is fixedly connected to the end face, facing the mouth part of the concave cavity 1a1, of the second annular supporting block 10 along the circumferential direction. Each second clamping flap 4 further comprises a clamping block 4a3 fixedly connected to the outer side of each second arc-shaped block 4a2, and an arc-shaped convex strip 4a31 is arranged on the outer side of each clamping block 4a 3.

As shown in fig. 2, the guide assembly comprises a positioning rod 6 fixed at the center of the bottom wall of the concave cavity 1a1 and a guide core 7 sleeved outside the positioning rod 6, wherein the guide core 7 is in conical surface contact with each arc-shaped block body two 4a 2. The positioning rod 6 is sleeved with a spring 8, the connecting plate 2 is provided with a blocking piece 9 extending into the concave cavity 1a1, and the guide core 7 abuts against the blocking piece 9 under the action of the elastic force of the spring 8. The second clamping petals 4a and the second annular supporting blocks 10 are of an integrated structure, namely, a structure identical to that of the elastic chuck is formed, and when the connecting plate 2 slides, the guide core 7 moves along with the connecting plate 2, so that the second arc-shaped blocks 4a2 are outwards tensioned under the action of the conical surface.

As shown in fig. 1 and 2, further, a mounting hole is provided in the center of the bottom wall of the cavity 1a1, and one end of the positioning rod 6 is screwed into the mounting hole. The guide core 7 is cylindrical blocky, a matching hole is formed in the center of one end face of the guide core 7, the positioning rod 6 is provided with a head, the positioning rod 6 penetrates through the guide core 7 from the matching hole, and the other end of the guide core 7 is in clearance fit with the center hole of the annular support block II 10. The spring 8 is sleeved on the positioning rod 6 in the matching hole, and two ends of the spring 8 are respectively abutted against the head and the hole bottom surface of the matching hole. The number of the blocking pieces 9 is a plurality, and each blocking piece 9 is columnar and distributed along the circumferential direction. Specifically, each blocking member 9 comprises a guide sleeve 9a passing through the bottom wall of the cavity 1a1 and a set screw 9b passing through the guide sleeve 9a and penetrating into the connection plate 2, the guide sleeve 9a being axially fixed between the set screw 9b and the connection plate 2.

As shown in fig. 2 and 3, an annular positioning block 13 is arranged outside the second clamping part 4, a plurality of second fasteners 14 are fixedly connected to the bottom wall of the concave cavity 1a1, and the positioning block 13 is fixed on each fastener. The edge of the end face of the positioning block 13 facing the mouth of the cavity 1a1 is provided with an annular flange 13a, and the annular flange 13a is positioned between each arc-shaped block 3a2 and each clamping block 4a 3. The positioning block 13 is positioned at the inner side of the first clamping part 3, and the first annular supporting block 11 is positioned between the positioning block 13 and the bottom wall of the concave cavity 1a 1. The second fastening piece 14 comprises a fixed sleeve 14a penetrating through the first annular supporting block 11 and a second fastening screw 14b penetrating through the positioning block 13 and the fixed sleeve 14a in sequence and being in threaded connection with the bottom wall of the concave cavity 1a1, and two ends of the fixed sleeve 14a are respectively abutted against the positioning block 13 and the bottom wall of the concave cavity 1a 1.

The clamp is mainly used when the thin-wall annular part 17 is processed, a worker places the thin-wall annular part 17 in the mounting channel 5 between the clamping part I3 and the clamping part II 4, and the thin-wall annular part 17 abuts against the end face of the annular flange 13 a. Then, the cylinder in the main shaft of the numerically controlled lathe is controlled to work, a piston rod of the cylinder pulls the connecting plate 2 to a direction away from the concave cavity 1a1, the connecting plate 2 drives the annular supporting blocks 11 to synchronously move through the fastening pieces 12, the arc-shaped blocks 3a2 on the clamping pieces 3a gradually shrink inwards under the action of the conical surface between the arc-shaped blocks and the opening of the concave cavity 1a1 in the moving process, and therefore the convex strips 3a21 are tightly propped against the outer peripheral surface of the thin-wall annular part 17.

While the connecting plate 2 moves, the blocking piece 9 on the connecting plate 2 is separated from the guide core 7, so that the blocking effect on the guide core 7 is lost, and the guide core 7 moves in the same direction with the connecting plate 2 under the action of the elastic force of the spring 8. In this way, the guide core 7 forces the arc-shaped blocks 4a2 to gradually expand outwards by the action of the conical surface, so that the convex strips 4a31 are tightly pressed against the inner peripheral surface of the thin-wall annular part 17. The clamping part I3 is clamped on the outer peripheral surface of the thin-wall annular part 17, and the clamping part II 4 is tightly propped against the inner peripheral surface of the thin-wall annular part 17, so that the inner and outer clamping of the thin-wall annular part 17 is formed, the situation of unilateral stress cannot occur at the thin wall of the thin-wall annular part 17, namely, the inner and outer clamping is utilized to form balance, the thin-wall annular part 17 cannot deform during clamping, the end surface of the thin-wall annular part 17 can keep good perpendicularity with the clamping surface after clamping, and therefore machining precision and product quality are guaranteed.

In the clamp, each clamping flap one 3a is fixed with a connecting plate 23 through an annular supporting block one 11, the guide core 7 and the connecting plate 2 form a linkage relation, the connecting plate 2 is directly driven by the existing oil cylinder in the main shaft of the numerical control lathe, and the clamp is not driven by other driving sources or modes, so that the structure is simpler and the cost is lower. Moreover, the inward contraction of the first clamping petals 3a and the outward tensioning of the second clamping petals 4a can be simultaneously realized only by one action of the oil cylinder, so that the clamping efficiency is improved well.

Example two

The present embodiment is basically the same in structure and principle as the first embodiment, except that: in this embodiment, the guiding assembly includes a guiding core 7 and a plurality of tie rods penetrating through the bottom wall of the cavity 1a1 to fix the guiding core 7 and the connecting plate 2, and the guiding core 7 contacts with each second clamping segment 4a in a conical surface.

The specific embodiments described herein are offered by way of example only to illustrate the spirit of the invention. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions thereof without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Claims

1. The fixture is used for clamping the inside and outside of a thin-wall annular part (17), and comprises a base (1), wherein a connecting plate (2) and a clamping assembly which is in linkage relation with the connecting plate (2) are arranged in the base (1) in a sliding manner along the direction of a central axis, a clamping part I (3) which is cylindrical and elastic is arranged on the clamping assembly, the fixture is characterized in that a clamping part II (4) which is cylindrical and elastic is also arranged on the clamping assembly, the clamping part II (4) is positioned at the inner side of the clamping part I (3) and an annular mounting channel (5) is arranged between the clamping part II and the clamping part II (4), conical surface contact is formed between the clamping part I (3) and the base (1), when the connecting plate (2) slides along the central axis direction, the clamping part I (3) and the clamping part II (4) can be mutually close through the conical surface contact, the clamping part I (3) comprises a plurality of clamping petals I (3 a), the clamping part II (4) comprises a plurality of clamping petals II (4 a), the outer side wall of each clamping petal I (3 a) is in conical surface contact with the base, the inner side wall of each clamping petal II (4 a) is in conical surface contact with the base, the base (1) comprises a base body (1 a) with a concave cavity (1 a 1) at one end and a guide component arranged in the concave cavity (1 a 1), the clamping component is arranged in the concave cavity (1 a 1), each clamping petal I (3 a) is matched with the inner wall at the mouth part of the concave cavity (1 a 1), The guide component is positioned at the inner side of each second clamping valve (4 a) and can enable the end part of each second clamping valve (4 a) to be outwards tensioned when the connecting plate (2) slides, each second clamping valve (4 a) is fixed on the bottom wall of the concave cavity (1 a 1), the guide component comprises a positioning rod (6) fixed at the center of the bottom wall of the concave cavity (1 a 1) and a guide core (7) sleeved outside the positioning rod (6), the guide core (7) is in conical surface contact with each second clamping valve (4 a), a spring (8) is sleeved on the positioning rod (6), a blocking piece (9) extending into the concave cavity (1 a 1) is arranged on the connecting plate (2), the guide core (7) is propped against the blocking piece (9) under the elastic force of the spring (8), The clamping valve II (4 a) comprises an arc-shaped sheet body II (4 a 1) and an arc-shaped block II (4 a 2) fixedly connected to the end part of the arc-shaped sheet body II (4 a 1), the clamping assembly comprises an annular support block II (10) fixed on the bottom wall of the concave cavity (1 a 1), each arc-shaped sheet body II (4 a 1) is fixedly connected to the annular support block II (10) along the circumferential direction, the guide core (7) is in clearance fit with the annular support block II (10), the clamping valve I (3 a) comprises an arc-shaped sheet body I (3 a 1) and an arc-shaped block I (3 a 2) fixedly connected to the end part of the arc-shaped sheet body I (3 a 1), the clamping assembly further comprises an annular support block I (11) arranged in the concave cavity (1 a 1) in a sliding mode, Each arc-shaped sheet body I (3 a 1) is fixedly connected to the annular supporting block I (11) along the circumferential direction, the connecting plate (2) is fixed with the annular supporting block I (11) through a plurality of fastening pieces I (12) penetrating through the bottom wall of the concave cavity (1 a 1), an annular positioning block II (13) is arranged outside the clamping part II (4), a plurality of fastening pieces II (14) are fixedly connected to the bottom wall of the concave cavity (1 a 1), the positioning block (13) is fixed on each fastening piece II (14), an annular flange (13 a) is arranged at the edge of one end face of the positioning block (13) facing the mouth of the concave cavity (1 a 1), the end part of the annular flange (13 a) is positioned between each arc-shaped block I (3 a 2) and each arc-shaped block II (4 a 2), The annular support block I (11) is positioned between the positioning block (13) and the bottom wall of the concave cavity (1 a 1), the fastening piece II (14) comprises a fixing sleeve (14 a) penetrating through the annular support block I (11) and a fastening screw II (14 b) penetrating through the positioning block (13) and the fixing sleeve (14 a) in sequence and being in threaded connection with the bottom wall of the concave cavity (1 a 1), two ends of the fixing sleeve (14 a) are respectively abutted against the positioning block (13) and the bottom wall of the concave cavity (1 a 1), the thin-wall annular part (17) is placed in the mounting channel (5), and the inward shrinkage of each clamping flap I (3 a) and the outward tensioning of each clamping flap II (4 a) are simultaneously realized through one-time action of an oil cylinder in a main shaft of the numerical control lathe.

2. The fixture according to claim 1, wherein an arc-shaped protruding strip I (3 a 21) is arranged on the inner side of each arc-shaped block I (3 a 2), and an arc-shaped protruding strip II (4 a 31) is arranged on the outer side of each arc-shaped block II (4 a 2).