CN110355394A - A kind of high-precision pneumatic chuck structure - Google Patents

Abstract

The invention relates to a high-precision pneumatic chuck structure, which is installed on a flange of a machine tool, and includes a rotating shaft fixedly connected with the flange, a pneumatic assembly arranged at the front of the rotating shaft, a chuck assembly arranged on the pneumatic assembly and The ventilated bearing is arranged at the rear of the rotating shaft. The ventilated bearing adopts an air static pressure bearing, and a ventilating groove is arranged in the rotating shaft. The ventilating groove communicates with the pneumatic component and the air static pressure bearing; part of the air introduced into the air static pressure bearing is in the air static pressure bearing The air film is formed, and the other part enters the pneumatic assembly through the air groove to drive the chuck assembly. Due to the homogenization effect of the gas film, the rotation accuracy can be further improved, and the influence of the shape error of the mechanical bearing on the rotation accuracy and rotation stability of the chuck is greatly reduced; The rotating part of the disk is separated from the stationary part, avoiding direct contact of mechanical parts and effectively reducing friction during operation.

Description

A High Precision Pneumatic Chuck Structure

technical field

The invention relates to the technical field of machine tool chuck production and manufacturing, in particular to a high-precision pneumatic chuck structure.

Background technique

Pneumatic chuck is a mechanical device that uses the radial movement of movable jaws evenly distributed on the chuck to clamp the workpiece. It is often installed on lathes, internal grinding machines and external grinding machines. With the development of ultra-precision machining and manufacturing technology, many high-tech products have higher and higher requirements for ultra-precision machining machine tools. Pneumatic chucks have the advantages of high clamping efficiency, high clamping precision, and simple chuck structure. It is widely used in high-precision turning and grinding.

The rotation of the chuck is driven by the connection between the flange and the spindle of the workpiece. The external compressed air source enters the air chamber of the chuck through the airway connector. The airway connector is a static part. The airway connector adopts bearing technology Reduces friction between the rotating and stationary parts of the chuck. As a chuck directly connected to the spindle, its rotation accuracy largely determines the rotation error of the workpiece end at high speed. In addition to the machining accuracy of the chuck itself, the bearing technology used in the airway connector also largely determines the rotation accuracy of the chuck.

Traditional contact rolling bearings are widely used in pneumatic chucks to reduce the friction between their stationary and rotating parts. Due to their own structure, it is difficult for traditional contact bearings to achieve extremely high machining accuracy, resulting in vibration during rotation Thereby reducing the rotation accuracy of the chuck. Crawling will occur during low-speed operation, and during long-term high-speed rotation, the thermal deformation of the chuck part caused by the frictional heat of the bearing will also reduce the rotation accuracy of the workpiece end.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-precision pneumatic chuck structure, which realizes the high-precision rotation of the chuck and has less vibration, and does not crawl at low speeds, and does not produce friction at high speeds. thermal phenomenon.

The technical solution adopted by the present invention to solve the technical problem is: a high-precision pneumatic chuck structure installed on the flange of the machine tool, including a rotating shaft fixedly connected with the flange, a pneumatic assembly arranged at the front of the rotating shaft, The chuck assembly arranged on the pneumatic assembly and the ventilated bearing arranged at the rear of the rotating shaft, the ventilated bearing adopts an aerostatic bearing, and a ventilating groove is arranged in the rotating shaft, and the ventilating groove communicates the pneumatic assembly and the air Static pressure bearing; part of the air introduced into the air static pressure bearing forms an air film in the air static pressure bearing, and the other part enters the pneumatic assembly through the air groove to drive the chuck assembly.

More specifically, the aerostatic bearing includes an air bearing guide rail and an air bearing arranged coaxially with the air bearing guide rail, and several throttles for axial thrust and radial support are arranged on the air bearing hole.

More specifically, the pneumatic assembly includes a pneumatic housing with the rotating shaft as the center, a pneumatic piston set in the pneumatic housing and sleeved on the rotating shaft, a front cover set on the pneumatic housing, and a pneumatic piston set between the front cover and the pneumatic piston. There is a return spring between them, an air chamber is formed between the pneumatic casing and the pneumatic piston, and the air chamber communicates with the ventilation groove.

More specifically, the throttle hole includes several radial throttle holes arranged radially, an axial throttle hole connected to several radial throttle holes, and an annular air supply groove connected to several radial throttle holes. Air intake holes are arranged on the annular air supply groove.

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

Further specifically, a groove is provided inside the front cover, and the return spring is located in the groove.

More specifically, the rotating shaft, the air bearing rail and the pneumatic housing are integrally formed.

More specifically, the chuck assembly includes a slidable power wedge disposed on the front cover, a claw disposed on the power wedge, and a protruding wedge disposed on the pneumatic piston and cooperating with the power wedge, so The said convex wedge protrudes obliquely in the direction away from the rotating shaft.

The beneficial effects of the present invention are: after adopting the above-mentioned structure, due to the homogenization effect of the gas film, the present invention can not only further improve the rotation accuracy compared with the pneumatic chuck using the traditional mechanical contact bearing, but also greatly reduce the The impact of the shape error of the ball or roller on the rotation accuracy and rotation stability of the chuck; at the same time, in the aerostatic bearing, since the air film is used to separate the rotating part of the chuck from the stationary part, direct contact with mechanical parts is avoided , effectively reducing the friction during operation, and there will be no crawling phenomenon.

Description of drawings

Fig. 1 is the sectional structure schematic diagram of the present invention;

FIG. 2 is an enlarged structural schematic diagram of part A of FIG. 1 .

In the figure: 1. flange; 2. rotating shaft; 3. ventilation slot; 4. air bearing; 5. air bearing; 6. pneumatic housing; 7. pneumatic piston; 8. front cover; 9. return spring; 10. Air chamber; 11. Power wedge; 12. Claw; 13. Convex wedge; 51. Radial orifice; 52. Axial orifice; 53. Annular air supply groove; 54. Air inlet.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, a high-precision pneumatic chuck structure is installed on the flange 1 of the machine tool, including the rotating shaft 2 fixedly connected with the flange 1, the pneumatic assembly arranged in front of the rotating shaft 2, and the pneumatic assembly arranged on the The chuck assembly on the top and the ventilated bearing arranged at the rear of the rotating shaft 2, the ventilated bearing adopts an aerostatic bearing, and the ventilating groove 3 is arranged in the rotating shaft 2, and the ventilating groove 3 communicates the pneumatic assembly and the air Static pressure bearing; part of the air introduced into the air static pressure bearing forms an air film in the air static pressure bearing, and the other part enters the pneumatic assembly through the ventilation groove 3 to realize the drive of the chuck assembly; by ventilating the air static pressure bearing , realize the adjustment of the chuck assembly and form the air film, and improve the rotation accuracy.

As shown in Figure 2, the aerostatic bearing includes an air bearing 4 and an air bearing 5 coaxially arranged with the air bearing 4, the air bearing 4 is fixed on the flange 1 and rotates with the flange 1, A number of orifices for axial thrust and radial support are set on the air bearing 5, and a number of axial orifices 52 are evenly opened around the shaft core of the air bearing 5 in the axial direction. In this case The middle axial throttling holes 52 are arranged in 8 groups, each group has one. The axial throttling holes 52 are through holes, and the openings on both sides correspond to the position of the flange 1 and the pneumatic components respectively; A number of radial throttling holes 51 are arranged in the radial direction of the bearing 5. In this case, 8 groups are set, each group has 3, and they are evenly distributed. In the same radial plane, the radial throttling holes 51 and the axial throttling holes At the same time, in order to ensure the communication between all the radial orifices 51 and the axial orifices 52, an annular air supply groove 53 is set on the air bearing 5, and the annular air supply groove 53 connects each radial A radial throttle hole 51 in the plane is connected, and at least one air inlet 54 is opened on the annular air supply groove 53 to realize air intake; and for the convenience of processing, the annular air supply groove 53 is arranged on the An annular groove is formed on the cylindrical surface, and a sealing ring is installed on the annular groove to realize the function of the annular air supply groove 53; the radial throttle hole 51 is processed as a through hole, which is located on one side of the cylinder surface of the air bearing 5 for sealing This method is also more convenient to clean up; the gas entering from the air inlet 54 passes through the radial orifice 51 and forms an air film between the air bearing 5 and the air bearing rail 4, and the gas passed through After the axial throttle hole 52, an air film is formed between the air bearing 5 and the flange 1, and between the air bearing 5 and the pneumatic assembly.

The pneumatic assembly includes a pneumatic casing 6 centered on the rotating shaft 2, a pneumatic piston 7 set in the pneumatic casing 6 and sleeved on the rotating shaft 2, a front cover 8 arranged on the pneumatic casing 6, and a pneumatic piston set between the front cover 8 and the pneumatic piston. 7 between the return spring 9, the air chamber 10 is formed between the pneumatic housing 6 and the pneumatic piston 7, and the ventilation groove 3 communicates with the air chamber 10, and the air chamber 10 is arranged on the side close to the flange 1 , the air chamber 10 is an annular space, and three ventilating grooves 3 are provided, all of which are connected to the air chamber 10; in order to facilitate the positioning of the return spring 9, three grooves are provided on the front cover 8, and the return spring 9 is three One-to-one correspondence is fixed in the groove; when working, the air static pressure bearing is ventilated, and the gas enters the ventilation groove 3 along the orifice, and the ventilation groove 3 passes the gas into the air chamber 10, and the air pressure in the air chamber 10 increases. Make the pneumatic piston 7 move away from the side of the flange 1 and compress the return spring 9. At this time, the clamping operation of the chuck assembly is realized; when it is not working, the ventilation is stopped, and the air pressure in the air chamber 10 decreases. The return spring 9 makes the pneumatic piston 7 return to the initial position, and at this time, the loosening operation of the chuck assembly is realized.

The chuck assembly includes a slidable power wedge 11 arranged on the front cover 8, a claw 12 arranged on the power wedge 11, and a protruding wedge 13 arranged on the pneumatic piston 7 and cooperating with the power wedge 11. The above-mentioned convex wedge 13 protrudes obliquely in the direction away from the rotating shaft 2; the chuck assembly is arranged in 3 groups, and is evenly distributed on the front cover 8 around the rotating shaft; when the pneumatic piston 7 drives the convex wedge 13 close to the power wedge 11, the convex wedge 13 makes the power wedge 11 move toward the center of the rotating shaft 2, and the power wedge 11 drives the claw 12 to move toward the center of the rotating shaft 2 to realize the clamping of the workpiece; when the pneumatic piston 7 drives the convex wedge 13 away from the power wedge 11, the convex wedge 13 make the power wedge 11 and the claw 12 away from the center of the rotating shaft 2, and loosen the workpiece.

Based on the above structure, in order to facilitate the installation, the rotating shaft 2, the air bearing guide rail 4 and the pneumatic housing 6 are integrally formed. During installation, only the corresponding parts need to be installed, which improves the installation efficiency.

To sum up, for the existing pneumatic chuck, this case adopts the aerostatic bearing to replace the existing mechanical contact bearing. Due to the homogenization error effect of the air film, the vibration is smaller than the traditional mechanical contact bearing, and the rotation accuracy is high. Under low speed conditions, there will be no crawling phenomenon, and under high speed conditions, there will be no friction and heat generation, which greatly increases the rotation accuracy and improves the machining accuracy.

It should be emphasized that: the above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention are valid. Still belong to the scope of the technical solution of the present invention.

Claims (9)

1. a kind of high-precision pneumatic chuck structure is installed on the ring flange (1) of lathe, including is fixedly connected with ring flange (1) Shaft (2), setting turning in the Pneumatic assembly of shaft (2) front, the chuck assembly that is arranged on Pneumatic assembly and setting The ventilation bearing at axis (2) rear portion, which is characterized in that the ventilation bearing uses aerostatic bearing, in the shaft (2) Interior setting air channel (3), the air channel (3) are connected to Pneumatic assembly and aerostatic bearing；The aerostatic bearing The air a part being passed through forms air film in aerostatic bearing, and another part enters Pneumatic assembly reality by air channel (3) Now to the driving of chuck assembly.

2. high-precision pneumatic chuck structure according to claim 1, which is characterized in that the aerostatic bearing includes Air-float guide rail (4) and the air-bearing (5) being coaxially disposed with air-float guide rail (4), are arranged axis on the air-bearing (5) Several throttle orifices acted on to thrust and radial support.

3. high-precision pneumatic chuck structure according to claim 1, which is characterized in that the Pneumatic assembly includes to turn Pneumatic housing (6) centered on axis (2), setting in pneumatic housing (6) and be set on shaft (2) air rammer (7), set The front cover (8) being placed on pneumatic housing (6), the reset spring (9) being set between front cover (8) and air rammer (7), it is described Gas chamber (10) are formed between pneumatic housing (6) and air rammer (7), the air channel (3) is connected to gas chamber (10).

4. high-precision pneumatic chuck structure according to claim 3, which is characterized in that the aerostatic bearing includes Air-float guide rail (4) and the air-bearing (5) being coaxially disposed with air-float guide rail (4), are arranged axis on the air-bearing (5) Several throttle orifices acted on to thrust and radial support.

5. according to the high-precision pneumatic chuck structure described in claim 2 or 4, which is characterized in that the throttle orifice packet Include several radial throttle orifices (51) being arranged radially, the axial throttle orifice (52) of several radial throttle orifices (51) of connection and connection The annular air supply trough (53) of several radial direction throttle orifices (51), is arranged air inlet (54) on the annular air supply trough (53).

6. high-precision pneumatic chuck structure according to claim 5, which is characterized in that the annular air supply trough (53) is Annular groove on air-bearing (5) cylinder is set, and sealing ring is set on the annular groove.

7. high-precision pneumatic chuck structure according to claim 3, which is characterized in that setting on the inside of the front cover (8) Groove, the reset spring (9) are located in groove.

8. high-precision pneumatic chuck structure according to claim 5, which is characterized in that the shaft (2), air-float guide rail (4) and pneumatic housing (6) is integrally formed.

9. high-precision pneumatic chuck structure according to claim 1, which is characterized in that the chuck assembly includes setting On front cover (8) and slidable power voussoir (11), the claw (12) that is set on power voussoir (11) and it is arranged in gas Convex wedge (13) in piston (7) and with power voussoir (11) cooperation, the convex wedge (13) incline to the direction far from shaft (2) Tiltedly stretch out.