CN210435395U

CN210435395U - High-precision pneumatic chuck structure

Info

Publication number: CN210435395U
Application number: CN201921349570.6U
Authority: CN
Inventors: 陈万群; 滕翔宇; 霍德鸿; 丁辉
Original assignee: Jiangsu Jijingkai High End Equipment Technology Co ltd
Current assignee: Jiangsu Jijingkai High End Equipment Technology Co ltd
Priority date: 2019-08-20
Filing date: 2019-08-20
Publication date: 2020-05-01
Anticipated expiration: 2029-08-20

Abstract

The utility model relates to a high-precision pneumatic chuck structure, which is arranged on a flange of a machine tool and comprises a rotating shaft fixedly connected with the flange, a pneumatic component arranged in the front part of the rotating shaft, a chuck component arranged on the pneumatic component and a ventilating bearing arranged at the rear part of the rotating shaft, wherein the ventilating bearing adopts an air hydrostatic bearing, a ventilating groove is arranged in the rotating shaft, and the ventilating groove is communicated with the pneumatic component and the air hydrostatic bearing; one part of air introduced into the aerostatic bearing forms an air film in the aerostatic bearing, and the other part of air enters the pneumatic assembly through the vent groove to drive the chuck assembly. Due to the homogenization effect of the gas film, the rotation precision can be further improved, and the influence of the shape error of the mechanical bearing on the rotation precision and the rotation stability of the chuck is greatly reduced; meanwhile, in the aerostatic bearing, the rotating part and the static part of the chuck are separated by adopting the air film, so that the direct contact of mechanical parts is avoided, and the friction force in the operation process is effectively reduced.

Description

High-precision pneumatic chuck structure

Technical Field

The utility model belongs to the technical field of the manufacturing technology of lathe chuck and specifically relates to a high accuracy air chuck structure is related to.

Background

The pneumatic chuck is a mechanical device for clamping a workpiece by radial movement of movable jaws uniformly distributed on the chuck, and is often mounted on a lathe, an internal grinding machine and an external grinding machine for use. Along with the development of the ultra-precision machining and manufacturing technology, the requirement of many high-tech products on the machining precision of an ultra-precision machining tool is higher and higher, and the pneumatic chuck is widely applied to high-precision turning and grinding due to the advantages of high clamping efficiency, high clamping precision, simple chuck structure and the like.

The rotation of chuck is connected the drive through ring flange and work piece main shaft, and outside compressed air source passes through the air chamber that air flue connector part got into the chuck, and air flue connector is static part, and air flue connector reduces the friction between chuck rotating part and the static part through adopting the bearing technique. The accuracy of the rotation of the chuck, which is directly connected to the spindle, determines to a large extent the rotation error of the workpiece end at high rotational speeds. In addition to the inherent machining precision of the chuck, the bearing technology used in the gas passage connector portion also largely determines the rotational precision of the chuck.

The traditional contact type rolling bearing is widely used on an air chuck to reduce friction between a static part and a rotating part of the air chuck, and due to the structure of the traditional contact type rolling bearing, the traditional contact type rolling bearing is difficult to achieve extremely high machining precision, so that vibration is generated in the rotating process to reduce the rotating precision of the chuck. Creep phenomenon occurs at low speed operation, and thermal deformation of the chuck portion caused by frictional heat generation of the bearing during long-time high-speed rotation also reduces the revolution accuracy of the workpiece end.

Disclosure of Invention

The utility model aims to solve the technical problem that a high accuracy air chuck structure is provided, it realizes that the high accuracy gyration of chuck vibrates simultaneously lessly, can not appear the phenomenon of crawling when the low speed, and can not produce the friction themogenesis phenomenon when high-speed yet.

The utility model provides a technical scheme that its technical problem adopted is: a high-precision pneumatic chuck structure is arranged on a flange plate of a machine tool and comprises a rotating shaft fixedly connected with the flange plate, a pneumatic assembly arranged at the front part of the rotating shaft, a chuck assembly arranged on the pneumatic assembly and a ventilating bearing arranged at the rear part of the rotating shaft, wherein the ventilating bearing adopts an air hydrostatic bearing, a ventilating groove is arranged in the rotating shaft, and the ventilating groove is communicated with the pneumatic assembly and the air hydrostatic bearing; one part of air introduced into the aerostatic bearing forms an air film in the aerostatic bearing, and the other part of air enters the pneumatic assembly through the vent groove to drive the chuck assembly.

More specifically, the aerostatic bearing comprises an air floatation guide rail and an air floatation bearing coaxially arranged with the air floatation guide rail, and a plurality of throttling holes with axial thrust and radial support functions are arranged on the air floatation bearing.

Further specifically, the pneumatic assembly comprises a pneumatic shell taking the rotating shaft as the center, a pneumatic piston arranged in the pneumatic shell and sleeved on the rotating shaft, a front cover arranged on the pneumatic shell, and a return spring arranged between the front cover and the pneumatic piston, an air chamber is formed between the pneumatic shell and the pneumatic piston, and the vent groove is communicated with the air chamber.

More specifically, the throttle holes comprise a plurality of radial throttle holes arranged in the radial direction, axial throttle holes communicated with the plurality of radial throttle holes and annular air supply grooves communicated with the plurality of radial throttle holes, and air inlet holes are formed in the annular air supply grooves.

More specifically, the annular air supply groove is an annular groove arranged on the cylindrical surface of the air bearing, and a sealing ring is arranged on the annular groove.

Further specifically, a groove is formed in the inner side of the front cover, and the return spring is located in the groove.

Further specifically, the rotating shaft, the air-floating guide rail and the pneumatic shell are integrally formed.

Further specifically, the chuck assembly comprises a power wedge which is arranged on the front cover and can slide, a clamping jaw which is arranged on the power wedge, and a convex wedge which is arranged on the pneumatic piston and matched with the power wedge, wherein the convex wedge obliquely extends in the direction away from the rotating shaft.

The utility model has the advantages that: after the structure is adopted, due to the homogenization effect of the gas film, compared with the pneumatic chuck utilizing the traditional mechanical contact type bearing, the utility model not only can further improve the rotation precision, but also greatly reduces the influence of the shape error of the ball or the roller in the mechanical bearing on the rotation precision and the rotation stability of the chuck; meanwhile, in the aerostatic bearing, the rotating part and the static part of the chuck are separated by adopting the air film, so that the direct contact of mechanical parts is avoided, the friction force in operation is effectively reduced, and the creeping phenomenon cannot occur.

Drawings

FIG. 1 is a schematic sectional view of the present invention;

fig. 2 is an enlarged schematic structural view of a portion a of fig. 1.

In the figure: 1. a flange plate; 2. a rotating shaft; 3. a vent channel; 4. an air-float guide rail; 5. an air bearing; 6. a pneumatic housing; 7. a pneumatic piston; 8. a front cover; 9. a return spring; 10. an air chamber; 11. a power wedge; 12. a claw; 13. a convex wedge; 51. a radial orifice; 52. an axial orifice; 53. an annular air supply groove; 54. and (4) air inlet holes.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 1, the high-precision pneumatic chuck structure is mounted on a flange plate 1 of a machine tool, and comprises a rotating shaft 2 fixedly connected with the flange plate 1, a pneumatic assembly arranged in front of the rotating shaft 2, a chuck assembly arranged on the pneumatic assembly, and a ventilating bearing arranged at the rear of the rotating shaft 2, wherein the ventilating bearing adopts an air hydrostatic bearing, a ventilating groove 3 is arranged in the rotating shaft 2, and the ventilating groove 3 is communicated with the pneumatic assembly and the air hydrostatic bearing; one part of air introduced into the aerostatic bearing forms an air film in the aerostatic bearing, and the other part of air enters the pneumatic assembly through the vent groove 3 to drive the chuck assembly; the air is introduced to the air hydrostatic bearing, so that the chuck assembly is adjusted and an air film is formed, and the rotation precision is improved.

As shown in fig. 2, the aerostatic bearing comprises an air-floating guide rail 4 and an air-floating bearing 5 coaxially arranged with the air-floating guide rail 4, the air-floating guide rail 4 is fixed on the flange plate 1 and rotates with the flange plate 1, a plurality of throttle holes for axial thrust and radial support are arranged on the air-floating bearing 5, a plurality of axial throttle holes 52 are uniformly arranged around the shaft core of the air-floating bearing 5 in the axial direction, the axial throttle holes 52 are arranged into 8 groups, each group has 1, the axial throttle holes 52 are through holes, and the openings at the two sides of the axial throttle holes respectively correspond to the positions of the flange plate 1 and the pneumatic component one by one; a plurality of radial throttle holes 51 are arranged in the radial direction of the air bearing 5, 8 groups are arranged in the scheme, each group comprises 3 throttle holes which are uniformly distributed, and the radial throttle holes 51 are communicated with the axial throttle holes 52 in the same radial plane; meanwhile, in order to ensure that all the radial throttle holes 51 are communicated with the axial throttle holes 52, an annular air supply groove 53 is formed in the air bearing 5, the annular air supply groove 53 is communicated with one radial throttle hole 51 in each radial plane, and at least one air inlet hole 54 is formed in the annular air supply groove 53 to realize air inlet; for convenience of processing, the annular air supply groove 53 is arranged on the cylindrical surface of the air bearing 5 to form an annular groove, and a sealing ring is arranged on the annular groove to realize the function of the annular air supply groove 53; the radial throttle hole 51 is processed into a through hole, and the through hole is positioned on the cylindrical surface of the air bearing 5, and one side of the through hole is sealed, so that the through hole is convenient to clean; after passing through the radial throttle hole 51, the gas entering from the gas inlet 54 forms a gas film between the gas bearing 5 and the gas guide rail 4, and after passing through the axial throttle hole 52, the gas film forms between the gas bearing 5 and the flange plate 1 and between the gas bearing 5 and the pneumatic assembly.

The pneumatic assembly comprises a pneumatic shell 6 taking the rotating shaft 2 as the center, a pneumatic piston 7 arranged in the pneumatic shell 6 and sleeved on the rotating shaft 2, a front cover 8 arranged on the pneumatic shell 6 and a return spring 9 arranged between the front cover 8 and the pneumatic piston 7, wherein an air chamber 10 is formed between the pneumatic shell 6 and the pneumatic piston 7, the vent groove 3 is communicated with the air chamber 10, the air chamber 10 is arranged at one side close to the flange plate 1, the air chamber 10 is an annular space, and 3 vent grooves 3 are all communicated into the air chamber 10; in order to position the return springs 9 conveniently, 3 grooves are formed in the front cover 8, and the return springs 9 are fixed in the grooves in a one-to-one correspondence mode, wherein 3 grooves are formed in the front cover; when the clamping device works, the air hydrostatic bearing is ventilated, air enters the vent groove 3 along the throttling hole, the vent groove 3 leads the air into the air chamber 10, the air pressure in the air chamber 10 is increased, so that the pneumatic piston 7 moves to one side far away from the flange plate 1 and compresses the return spring 9, and the clamping operation of the flange plate assembly is realized; when the chuck does not work, the ventilation is stopped, the air pressure in the air chamber 10 is reduced, the return spring 9 enables the pneumatic piston 7 to recover to the initial position, and at the moment, the chuck component is loosened.

The chuck assembly comprises a power wedge block 11 which is arranged on the front cover 8 and can slide, a clamping jaw 12 which is arranged on the power wedge block 11, and a convex wedge 13 which is arranged on the pneumatic piston 7 and matched with the power wedge block 11, wherein the convex wedge 13 extends in an inclined way in the direction far away from the rotating shaft 2; the chuck components are arranged in 3 groups and are uniformly distributed on the front cover 8 around the rotating shaft; when the pneumatic piston 7 drives the convex wedge 13 to be close to the power wedge block 11, the convex wedge 13 enables the power wedge block 11 to move towards the center of the rotating shaft 2, and the power wedge block 11 drives the clamping jaws 12 to move towards the center of the rotating shaft 2, so that a workpiece is clamped; when the pneumatic piston 7 drives the convex wedge 13 to be far away from the power wedge 11, the convex wedge 13 enables the power wedge 11 and the clamping jaws 12 to be far away from the center of the rotating shaft 2, and the workpiece is loosened.

Based on the structure, in order to facilitate installation, the rotating shaft 2, the air floatation guide rail 4 and the pneumatic shell 6 are integrally formed, and during installation, only corresponding parts need to be installed, so that the installation efficiency is improved.

To sum up, to current air chuck, the present case adopts aerostatic bearing to replace current mechanical contact bearing, because the homogenization error effect of air film, and is little than traditional mechanical contact bearing vibration, and the gyration precision is high, under low rotational speed operating mode, the phenomenon of crawling can not appear, under high speed operating mode, also can not produce the friction themogenesis phenomenon, greatly increased the gyration precision, improved the machining precision.

It is to be emphasized that: the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form, and any simple modifications, equivalent changes and modifications made by the technical spirit of the present invention to the above embodiments are all within the scope of the technical solution of the present invention.

Claims

1. A high-precision pneumatic chuck structure is arranged on a flange plate (1) of a machine tool and comprises a rotating shaft (2) fixedly connected with the flange plate (1), a pneumatic assembly arranged at the front part of the rotating shaft (2), a chuck assembly arranged on the pneumatic assembly and a ventilating bearing arranged at the rear part of the rotating shaft (2), and is characterized in that the ventilating bearing adopts an aerostatic bearing, a ventilating groove (3) is arranged in the rotating shaft (2), and the ventilating groove (3) is communicated with the pneumatic assembly and the aerostatic bearing; one part of air introduced into the aerostatic bearing forms an air film in the aerostatic bearing, and the other part of air enters the pneumatic assembly through the vent groove (3) to drive the chuck assembly.

2. The high-precision air chuck structure according to claim 1, wherein the aerostatic bearing comprises an air bearing rail (4) and an air bearing (5) coaxially arranged with the air bearing rail (4), and a plurality of orifices for axial thrust and radial support are arranged on the air bearing (5).

3. The high-precision pneumatic chuck structure according to claim 1, wherein the pneumatic assembly comprises a pneumatic housing (6) centered on the rotating shaft (2), a pneumatic piston (7) disposed in the pneumatic housing (6) and sleeved on the rotating shaft (2), a front cover (8) disposed on the pneumatic housing (6), and a return spring (9) disposed between the front cover (8) and the pneumatic piston (7), an air chamber (10) is formed between the pneumatic housing (6) and the pneumatic piston (7), and the vent groove (3) is communicated with the air chamber (10).

4. A high precision air chuck structure according to claim 3, characterized in that said aerostatic bearing comprises an air bearing rail (4) and an air bearing (5) coaxially arranged with the air bearing rail (4), said air bearing (5) being provided with orifices for axial thrust and radial support.

5. A high-precision air chuck structure according to claim 2 or 4, characterized in that the throttling holes comprise a plurality of radial throttling holes (51) which are radially arranged, axial throttling holes (52) which are communicated with the plurality of radial throttling holes (51) and annular air supply grooves (53) which are communicated with the plurality of radial throttling holes (51), and air inlet holes (54) are arranged on the annular air supply grooves (53).

6. A high accuracy air chuck structure according to claim 5, characterized in that said annular air supply groove (53) is an annular groove provided on the cylindrical surface of the air bearing (5), and a seal ring is provided on the annular groove.

7. A high precision pneumatic chuck structure according to claim 3, characterized in that the inner side of the front cover (8) is provided with a groove, and the return spring (9) is positioned in the groove.

8. The structure of the high-precision pneumatic chuck according to claim 5, characterized in that the rotating shaft (2), the air rail (4) and the pneumatic housing (6) are integrally formed.

9. A high precision pneumatic chuck construction according to claim 1, characterized in that the chuck assembly comprises a power wedge (11) slidably mounted on the front cover (8), a jaw (12) mounted on the power wedge (11), and a cam (13) mounted on the pneumatic piston (7) and cooperating with the power wedge (11), the cam (13) projecting obliquely away from the spindle (2).