CN103047220B - Cylinder barrel air supply pressure equalizing air floatation friction-free air cylinder - Google Patents

Abstract

Disclosed is a cylinder barrel air supply pressure equalizing air floatation friction-free air cylinder. A piston is sleeved in a cylinder barrel with clearance between each other. The piston is fixedly connected with a piston rod. One end of the cylinder barrel is provided with a base while the other end of the cylinder barrel is provided with an end cover. An air source inlet is arranged on the base. The piston rod penetrates through the end cover. The cylinder barrel comprises an outer cylinder barrel and a microporous material layer, wherein the microporous material layer is attached to the inner wall of the outer cylinder barrel, the outer wall of the outer cylinder barrel is provided with an air inlet hole, the microporous material layer is provided with a first groove in axial distribution at the outer wall air inlet hole, the contact surface of the microporous material layer with the inner wall of the outer cylinder barrel is provided with a second groove along the circumferential direction, and the second groove is distributed on the surface of the microporous material layer axially and evenly. One side, close to the air inlet, of the piston is provided a circular third groove. A hole is radially punched in the third groove to be communicated with a cavity, close to a rod cavity, of the piston. The piston rod is connected with one end of a piston cavity. The cavity is communicated with the rod cavity in the cylinder barrel through a through hole. By the air cylinder high in control precision, influences of high-low pressure air flows on air film production are avoided.

Description

Cylinder air supply equal pressure air bearing frictionless cylinder

technical field

The invention relates to an air flotation cylinder. the

Background technique

Ordinary cylinders usually use mechanical seals, and there is contact friction between the cylinder and the piston. the

Traditional low-friction cylinders rely on improving machining accuracy, using special low-friction materials or grease lubrication to reduce friction, but there are defects such as difficult processing, high cost, difficult maintenance and short life; or by improving the sealing form to reduce friction For example, the German FESTO company uses a special sealing technology to apply to the cylinder, using a one-way sealing ring, which has very small sliding resistance. Japan's SMC company adopts ball guide sleeve technology and gap sealing technology. This low-friction cylinder has made breakthroughs in uniform velocity, high and low pressure friction, high speed and high frequency. Complicated, difficult to process and manufacture, and expensive. the

In order to meet the requirements of ultra-precision constant force output control and micro-pressure action control, gas lubrication technology is applied to realize zero-friction cylinder. For example, the patent application No. 201120080863.6 "A Frictionless Cylinder with Air Bearing" has announced a frictionless cylinder designed according to the principle of air flotation. There is a very small gap between the cylinder and the piston. Evenly distributed orifices are arranged in the radial direction, and the piston in the cylinder is supplied with air through the hollow piston rod and hose, and connected by a ball joint so that the frictionless cylinder can withstand a certain radial load without the piston being stuck in the cylinder Inside. However, the air supply method through the hollow piston rod and hose is complex, cumbersome to assemble, and difficult to maintain. Later, the frictionless cylinder was optimized, and the compressed air in the cylinder's own cavity was used as a lubricant to introduce the gas into the gap to make the piston In a fully suspended state in the cylinder, the piston and cylinder do not touch each other, thereby eliminating the friction between the piston and cylinder in the cylinder structure. However, no matter which air supply method is used, because there is a gap between the piston and the cylinder, there is a large pressure difference between the high-pressure chamber and the low-pressure chamber of the cylinder, so that air pressure flow will be formed in the gap, which directly affects the passage of the piston. The air pressure film formed by the orifice in the gap, on the other hand, the premise of the formation of the air film is that there is a certain pressure difference in the gap, and the air pressure in the gap near the end of the high pressure chamber increases, resulting in uneven thickness and pressure distribution of the gas film. The stability, precision and carrying capacity of the frictionless cylinder have been affected. the

Contents of the invention

In order to overcome the deficiencies of existing air flotation cylinders that the high and low pressure air flow affects the air film and the control accuracy is low, the present invention provides a cylinder air supply balance that effectively avoids the impact of high and low pressure air flow on the air film and has high control accuracy. Pressure type air bearing frictionless cylinder. the

The technical solution adopted by the present invention to solve its technical problems is:

An air-floating and friction-free cylinder with air supply and pressure equalization for the cylinder. The air-flotation and friction-free cylinder includes a cylinder, a piston, a piston rod, a base and an end cover. The piston is set in the cylinder and exists between the cylinder. gap, the piston is fixedly connected to one end of the piston rod, the base is installed at one end of the cylinder, the end cover is installed at the other end of the cylinder, the air inlet is provided on the base, and the piston rod passes through the end Cover, the cylinder includes an outer cylinder and a microporous material layer, a layer of microporous material is added on the inner wall of the outer cylinder, and there are air inlet holes on the outer wall of the outer cylinder, and the microporous material layer is placed on the outer wall of the outer cylinder. There is a first axially distributed groove at the air inlet hole on the outer wall, and the surface of the microporous material layer in contact with the inner wall of the outer cylinder has a second groove along the circumferential direction, and the second groove is formed on the surface of the microporous material. The surface is uniformly distributed in the axial direction; the piston has a third groove on the side close to the air inlet, and a hole is punched radially from the third groove to communicate with the cavity on the side of the piston close to the rod cavity. It is connected with one end of the piston having a cavity, and the cavity communicates with the rod cavity in the cylinder through the through hole.

Further, the air inlet and the air inlet on the outer wall of the cylinder are connected to the same air source. the

The beneficial effects of the present invention are mainly manifested in: effectively avoiding the influence of high and low pressure airflow on the gas film, and having high control precision. the

Description of drawings

Fig. 1 is a schematic diagram of an air-floating frictionless cylinder with air supply and equal pressure from the cylinder. the

Detailed ways

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

Referring to Fig. 1 , an air-floating frictionless air cylinder with equal pressure supplied by a cylinder is composed of a cylinder, a piston 6, a piston rod 7, a base 1, and an end cover 8. The piston 6 is set in the cylinder and There is a very small gap 14 between them, the piston is fixedly connected to one end of the piston rod 7, the base 1 is installed at one end of the cylinder, the end cover 8 is installed at the other end of the cylinder, and the air source is provided on the base. Port 15, the piston rod 7 passes through the end cover 8; the cylinder is composed of an outer cylinder 2 and a microporous material layer 3, and a layer of microporous material layer 3 is added on the inner wall of the outer cylinder 2, There is an air inlet 13 on the outer wall of the outer cylinder 2, and the microporous material layer 3 has a first groove 11 axially distributed at the air inlet, and the microporous material layer 3 and the outer cylinder 2 The surface in contact with the inner wall has second grooves 4 along the circumferential direction, and the second grooves 4 are uniformly distributed axially on the surface of the microporous material layer. The piston has a third groove on the side near the air inlet, and the hole 5 is drilled radially from the third groove to communicate with the cavity on the side of the piston near the rod cavity. The piston rod 7 is threaded with the piston 6. One end with a cavity is connected, and the cavity communicates with the rod cavity in the cylinder through the through hole 12. the

Described air source air inlet 15 and the air inlet 13 on the outer wall of the cylinder are connected to the same air source to ensure that the pressure is the same. the

In this embodiment, the cylinder is designed according to the principle of the air bearing and air bearing sleeve. The high-pressure gas enters from the air inlet of the cylinder and pushes the piston to move. At the same time, the gas passes through the air inlet on the cylinder The microporous material layer on the inner wall of the cylinder forms an air film in the gap between the piston and the cylinder. The two ends of the piston form a high-pressure chamber and a low-pressure chamber according to the difference in gas pressure. The premise for the gas to flow out of the microporous material is that there is a pressure difference. Since the gas in the high-pressure chamber and the gas in the cylinder are connected to the same gas source, there is no part of the high-pressure chamber. Gas leakage, and part of the airflow in the low-pressure cavity will leak from the microporous material layer, but because the leakage is extremely small, it is a feasible design. One end of the piston is affected by the gas in the high-pressure chamber, which causes the pressure in the gap to rise, which is not conducive to the formation of a stable gas film. Therefore, there is a pressure relief groove on the piston. The pressure relief groove communicates with the low-pressure chamber, and the gas entering the gap from the high-pressure chamber passes through After the damping is sealed, it is left out of the pressure relief groove, and at the same time, a low pressure area in the gap is created, which promotes the formation of a stable air film. the

The above examples are used to explain the present invention, rather than to limit the present invention, within the spirit of the present invention and the protection scope of the claims, any modification and change to the present invention will fall into the protection scope of the present invention. the

Claims (2)

1. A cylinder barrel air supply equal pressure type air-floating frictionless cylinder, the air-floating frictionless cylinder comprises a cylinder barrel, a piston, a piston rod, a base and an end cover, and the piston is sleeved in the cylinder barrel and connected to the cylinder barrel There is a gap between them, the piston is fixedly connected to one end of the piston rod, a base is installed at one end of the cylinder, an end cover is installed at the other end of the cylinder, an air inlet is provided on the base, and the piston rod passes through The end cover is characterized in that: the cylinder includes an outer cylinder and a microporous material layer, a layer of microporous material is added on the inner wall of the outer cylinder, and there are air inlet holes on the outer wall of the outer cylinder, so The microporous material layer has a first axially distributed groove at the air inlet of the outer wall, and the surface of the microporous material layer in contact with the inner wall of the outer cylinder has a second groove along the circumferential direction, and the second groove The grooves are uniformly distributed in the axial direction on the surface of the microporous material layer; the piston has a third groove on the side close to the air inlet, and the cavity on the side of the piston close to the rod cavity is punched radially from the third groove The piston rod is connected to one end of the piston with a cavity, and the cavity communicates with the rod cavity in the cylinder through a through hole. 2. The air-floating frictionless air cylinder with equal pressure supplied by the cylinder according to claim 1, characterized in that: the air inlet and the air inlet on the outer wall of the cylinder are connected to the same air source.