CN111946816B - Air piston and cylinder - Google Patents

Abstract

The invention discloses an air-floating piston and an air cylinder, which comprise a piston main body, wherein an air cavity is arranged in the piston main body and is controlled by a one-way air inlet valve to be closed or communicated with the outside of the piston main body; the piston main body is provided with a mounting hole, and the mounting hole is communicated with the air cavity and the outside of the piston main body along the radial direction of the piston main body; the throttling plug is assembled in the mounting hole; a through hole is formed in the throttling plug along the axial direction of the throttling plug, a capillary tube is fixed in the through hole, one end of the capillary tube extends out of the through hole and extends into the air cavity, and the air cavity is communicated with the outside of the piston main body through the capillary tube. According to the air floating piston and the air cylinder, the capillary tube with the inner diameter of 0.05-0.2 mm is used for replacing the throttling slit which is directly processed in the throttling plug, the requirement of the air floating piston on the processing precision is greatly reduced by using the capillary tube, the processing cost is low, the assembly difficulty is small, and the air floating piston and the air cylinder have high air film rigidity.

Description

Air piston and cylinder

technical field

The invention relates to the technical field of power machinery, in particular to an air-floating piston, and also to a cylinder containing the air-floating piston.

Background technique

Small regenerative low-temperature refrigerators are usually driven by linear motors, and gap sealing (unilateral gap 12-25un) technology is used between the piston and the cylinder. In order to ensure friction-free movement between the piston and the cylinder, gas bearing technology is required. The high-pressure air film in the air gap between the cylinder and the cylinder provides sufficient radial support for the piston. The traditional air-floating piston has a throttling slit in the throttling plug, and uses the throttling and stabilizing effect of the throttling slit. When the gas is output from the throttling slit, the gas speed drops suddenly, and the kinetic energy is converted into the pressure supporting the piston. Potential energy, thus providing radial support to the piston. The slit width of the throttling slit is in the range of 0.05-0.5mm. In the actual production process, the processing accuracy of the throttling slit is too high, resulting in the high processing cost of the air-floating piston, and it is difficult to achieve low-cost batch production. Production.

Contents of the invention

The technical problem to be solved by the present invention is to provide an air-floating piston and cylinder, which reduces the requirements for processing accuracy, has low processing cost, is less difficult to assemble, and has higher air film rigidity.

In order to solve the above technical problems, the present invention provides an air bearing piston, comprising:

The piston main body is provided with an air cavity inside, and the air cavity is controlled by a one-way air intake valve to be closed or communicated with the outside of the piston main body; the piston main body is provided with a mounting hole along the The radial direction of the piston body communicates with the air cavity and the outside of the piston body;

a throttling plug, the throttling plug is assembled in the installation hole;

The throttling plug is provided with a through hole along its axial direction, and a capillary is fixed in the through hole, and one end of the capillary protrudes from the through hole and extends into the air cavity, so that the air cavity also passes through the air cavity. The capillary communicates with the outside of the piston body.

In a preferred embodiment of the present invention, it further includes that one end of the capillary extending into the air cavity has a 90° bending portion, and the bending direction of the 90° bending portion is away from the air inlet of the air cavity .

In a preferred embodiment of the present invention, it further includes that the portion of the capillary extending into the air cavity is helically arranged along the outer wall of the throttle plug.

In a preferred embodiment of the present invention, it further includes that the outer diameter of the capillary matches the inner diameter of the through hole, and the two are fixed by gluing.

In a preferred embodiment of the present invention, it further includes that when the throttle plug is assembled in the installation hole, the end cap of the throttle plug is lower than the opening of the installation hole, and the hole of the installation hole The diameter of the port is 1.5 to 2.5 times the outer diameter of the end cap of the throttle plug.

In a preferred embodiment of the present invention, it further includes that the throttling plug is threadedly fitted in the installation hole, and its end away from the end cap protrudes from the installation hole and extends into the air cavity.

In a preferred embodiment of the present invention, it further includes that two air cavities are arranged in the piston main body, the two air cavities are arranged at intervals along the axial direction of the piston main body, and the two air cavities pass through the air channel connected.

In a preferred embodiment of the present invention, it further includes that the piston body is provided with a valve seat, and the valve seat and the piston body have an interference fit to close the air cavity, and the valve seat is provided with a valve for communicating with the air cavity. The air intake passage outside the cavity and the piston main body, the one-way air intake valve is rotatably connected to the valve seat, and the free end of the one-way air intake valve blocks the air intake passage.

In a preferred embodiment of the present invention, it further includes that the main body part of the one-way intake valve includes an arc segment.

Based on the same inventive concept, the present invention also provides a cylinder, including the air-floating piston.

Beneficial effects of the present invention:

The air-floating piston and cylinder of the present invention use a capillary with an inner diameter of 0.05-0.2mm instead of directly processing the throttling slit in the throttling plug, and utilize the throttling and stabilizing effect of the capillary. When the gas is output from the installation hole, the gas speed suddenly The kinetic energy is fully converted into the pressure potential energy supporting the piston, thereby providing sufficient radial support for the piston, and the use of capillary tubes greatly reduces the requirements for machining accuracy of the air-floating piston, with low processing costs, low assembly difficulty, and a high air film stiffness.

Description of drawings

Fig. 1 is the structural representation of air-floating piston in the preferred embodiment of the present invention;

Fig. 2 is the schematic diagram of the axial section of the air bearing piston shown in Fig. 1;

Fig. 3 is a schematic diagram of the working principle of the air-floating piston of the present invention;

Fig. 4 is a schematic structural view of a throttle plug in a preferred embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a throttle plug in another embodiment of the present invention.

Explanation of symbols in the figure:

1-Cylinder, 2-Piston body, 4-Valve seat, 6-Cavity, 8-One-way intake valve, 10-Installation hole, 12-Throttle plug, 14-Through hole, 16-Capillary, 18-90 °bending part, 20-end cap, 22-screw, 24-head, 26-intake channel, 27-inlet, 28-arc segment, 30-air channel, 32-cylindrical groove, 34 -Threaded hole.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the examples given are not intended to limit the present invention.

Example

The embodiment of the present invention discloses an air-floating piston. As shown in FIGS. The one-way intake valve 8 is controlled to be closed or connected to the outside of the piston main body 2; specifically, the piston main body 2 is provided with a valve seat 4, and the valve seat 4 and the piston main body 2 are closed by interference fit. The air cavity 6, the valve seat 4 is provided with an air intake passage 26 communicating with the air cavity 6 and the outside of the piston body 2, the one-way intake valve 8 is rotatably connected to the valve seat 4, and the The free end of the one-way intake valve 8 blocks the intake passage 26 . When the external pressure of the piston main body 2 is greater than the pressure of the air chamber 6, the air outside the piston main body 2 pushes open the one-way intake valve 8, and the external high-pressure gas enters the air chamber 6 through the air intake passage 26; otherwise, when When the external pressure of the piston body 2 is lower than the pressure of the air chamber 6 , the one-way air intake valve 8 blocks the air intake channel 26 to prevent the gas outside the piston body 2 from entering the air chamber 6 .

The piston body 2 is provided with a mounting hole 10, the mounting hole 10 communicates with the air cavity 6 and the outside of the piston body 2 along the radial direction of the piston body 2, and the throttle plug 12 is assembled on the In the installation hole 10; the throttling plug 12 is provided with a through hole 14 along its axial direction, and the capillary 16 is fixed in the through hole 14, and the inner diameter of the capillary 16 is 0.05 ~ 0.2mm, and the capillary 16 One end protrudes from the through hole 14 and extends into the air chamber 6 , so that the air chamber 6 communicates with the outside of the piston body 2 through the capillary 16 .

Figure 3 is a schematic diagram of the working principle of the air-floating piston. When in use, the air-floating piston and the cylinder block are in clearance fit. When the external pressure of the piston is greater than the pressure of the air chamber 6, the external gas pushes open the one-way intake valve 8, and the external high-pressure gas Enter the air cavity 6 through the air intake channel 26 in the valve seat 4, and then spray out from the orifice of the installation hole 10 through the throttling and stabilizing effect of the capillary 16, and evenly spray to the inner surface of the cylinder; based on fluid mechanics Bernoulli's principle, when the gas is output from the orifice of the installation hole 10, the gas velocity drops suddenly, and all the kinetic energy is converted into the pressure potential energy supporting the piston, so as to provide sufficient radial support for the piston and realize frictionless between the piston and the cylinder sports.

The outer diameter of the capillary 16 is matched with the inner diameter of the through hole 14, and the capillary is used to replace the throttle slit of the traditional air flotation or sprinkler, compared with the 0.05-0.2mm slit width processed on the throttle plug 12 The throttling slit, the air-floating piston of the embodiment of the present invention, the processing difficulty of processing the through hole 14 adapted to the capillary 16 on the throttle plug 12 is greatly reduced, and the processing accuracy requirements for the through hole 14 are also greatly reduced, so that The processing cost of the air bearing piston is reduced accordingly. On the other hand, in the traditional air-floating piston, due to the small slit width of the throttling slit, it is difficult to ensure that the throttling slit is not blocked during the assembly process, which makes the assembly of the air-floating piston more difficult. In the embodiment of the present invention, the capillary 16 is used instead, which directly overcomes the problem of high assembly difficulty, brings technical advantages of low assembly difficulty, and has high air film stiffness, providing sufficient radial support for the piston.

Specifically, the capillary 16 and the through hole 14 are fixed by gluing. In one implementation of gluing and fixing, use a very fine brush to pick up a little water-like epoxy glue, and evenly apply it to the through hole 14 of the throttle plug 12. The inner wall in contact with the capillary 16, then insert the capillary 16 into the through hole 14, when inserting the capillary 16, control the end of the inserted capillary 16 to be lower than the opening of the through hole 14, and use an alcohol cotton ball to position the through hole 14 before the glue dries Wipe away the glue that has been squeezed and spilled. In order to prevent capillary 16 and through hole 14 from blocking the inner diameter of capillary 16 during the gluing process, as shown in FIG.

The throttle plug 12 includes a screw rod 22 and an end cap 20, the throttle plug 12 is threadedly fitted in the installation hole 10, and its end away from the end cap 20 protrudes from the installation hole 10 and extends to Inside the air chamber 6. Specifically, the mounting hole 10 includes a cylindrical groove 32 at the opening and a threaded hole 34 communicating therewith. When the throttle plug 12 is assembled in the mounting hole 10, the threaded hole 34 is screwed tightly through the screw rod 22. The end cap 20 is accommodated in the cylindrical groove 32 , and the brim of the end cap 20 is lower than the outer surface of the piston body 2 . It can be seen from the formula F=P·A that when the pressure P of the gas ejected from the through hole 14 is constant, the size F of the air buoyancy force is positively related to the cross-sectional area A of the cylindrical groove 32, in order to ensure that the gas piston can provide sufficient air buoyancy force , A must be within a reasonable range, if A is too small, the gas ejected from the through hole 14 will not be able to fully diffuse and equalize the pressure, the gas pressure will not be fully utilized, and the buoyancy will be uneven; if A is too large, the gas will diffuse excessively and cause gas The pressure drop and the air buoyancy are too small. In the technical solution of this embodiment, when the throttle plug 12 is assembled in the installation hole 10, the end cap 20 of the throttle plug 12 is lower than the opening of the installation hole 10 , and the diameter of the opening of the mounting hole 10 (that is, the opening of the cylindrical groove 32 ) is 1.5 to 2.5 times the outer diameter of the end cap 20 of the throttle plug 12 .

Referring to Figures 3 and 4, the end of the capillary 16 extending into the air chamber 6 has a 90° bending portion 18, in order to avoid uneven pressure at the outlet of the through hole 14 due to the influence of the dynamic pressure of the air inlet 27 , the bending direction of the 90° bending portion 18 is away from the air inlet 27 of the air chamber 6 .

It can be understood that, in order to uniform the radial bearing capacity of the piston, the piston body 2 is provided with a plurality of mounting holes 10 along the circumferential direction (for example, four mounting holes 10 are arranged at intervals along the circumferential direction), corresponding to each Each of the mounting holes 10 is configured with one throttle plug 12 .

In another embodiment, in order to further uniform the radial bearing capacity of the piston, the piston body 2 is provided with two air cavities 6, and the two air cavities 6 are arranged at intervals along the axial direction of the piston body 2, And the two air cavities 6 communicate through the air channel 30 . Specifically, when changing from one air cavity 6 to two air cavities 6, a seal head 24 is provided in the piston body 2, and the seal head 24 is in interference fit with the piston body 2. At this time, the seal head 24 and the valve The seat 4 cooperates to divide the interior of the piston main body 2 into two air chambers 6 arranged at intervals in the axial direction. A plurality of mounting holes 10 are arranged corresponding to each air chamber 6 on the piston main body 2, and each of the mounting holes is equipped with a throttle plug 12. Based on the above principles, setting two air chambers 6 can Further even the radial bearing capacity of the piston.

As a further improvement of the present invention, one end of the one-way intake valve 8 is rotatably connected to the valve seat 4, and the other end (i.e. its free end) blocks the intake passage 26. When the external pressure is higher than the pressure of the air cavity 6 , the one-way intake valve 8 swings with its connection point with the valve seat 4 as a fulcrum (or the root of the one-way intake valve 8), as shown in Figure 1, in the technical solution of this embodiment, the one-way intake valve The main part of air valve 8 comprises arc section 28, and the arc section 28 of one-way intake valve 8 can buffer the force on its root when one-way intake valve 8 swings, so that one-way intake valve 8 is not easy to be damaged. Break off, prolong the service life of one-way intake valve 8.

In another embodiment of the present invention, in view of the application situation where the air inlet pressure of the air cavity 6 is relatively high, the length of the capillary 16 needs to be increased to further reduce the pressure of the gas ejected from the through hole 14, and the longer capillary 16 is also The pressure stabilizing effect can be enhanced, so that the pressure at the outlet of the through hole 14 is more uniform. When the length of the capillary 16 increases, as shown in FIG. The outer wall of 12 is spirally arranged. Under the limited length of the capillary 16 , the helical arrangement has greater resistance along the course than the straight tube arrangement, so that the throttling and pressure stabilization effect of the capillary 16 is more significant. On the other hand, when the length of the capillary 16 is increased by spiral setting to apply to the scene with high intake pressure, it is beneficial to reduce the diameter of the air flotation piston compared with the straight tube setting; based on the same principle, using the capillary 16 to replace the traditional air The throttle slit of the floating piston can reduce the diameter of the air floating piston by increasing the length of the capillary 16 .

The embodiment of the present invention also discloses a cylinder, which includes the air-floating piston in the above embodiments. The cylinder contains all the technical effects of the air-floating piston, and can also realize frictionless movement between the cylinder and the piston, improving the use of the piston. life.

The above-mentioned embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention shall be determined by the claims.

Claims (4)

1. An air-floating piston, comprising, The piston main body is provided with an air cavity inside, and the air cavity is controlled by a one-way air intake valve to be closed or communicated with the outside of the piston main body; the piston main body is provided with a plurality of installation holes along the circumferential direction, The installation hole communicates with the air chamber and the outside of the piston body along the radial direction of the piston body; Throttle plugs, the throttle plugs are assembled in the installation holes, and each of the installation holes is equipped with a throttle plug; It is characterized in that: the throttling plug is provided with a through hole along its axial direction, a capillary is fixed in the through hole, and one end of the capillary protrudes from the through hole and extends into the air cavity, so that the The air chamber also communicates with the outside of the piston body through the capillary; One end of the capillary extending into the air cavity has a 90° bending portion, and the bending direction of the 90° bending portion is away from the air inlet of the air cavity; The part of the capillary extending into the air cavity is arranged spirally along the outer wall of the throttle plug; The outer diameter of the capillary matches the inner diameter of the through hole, and the two are fixed by gluing; When the throttle plug is assembled in the installation hole, the end cap of the throttle plug is lower than the opening of the installation hole, and the diameter of the opening of the installation hole is outside the end cap of the throttle plug. 1.5~2.5 times the diameter; The throttling plug is threadedly fitted in the mounting hole, and its end away from the end cap protrudes from the mounting hole and extends into the air cavity; The piston body is provided with a valve seat, and the valve seat and the piston body have an interference fit to close the air cavity, and the valve seat is provided with an air intake passage connecting the air cavity and the outside of the piston body, so The one-way intake valve is rotatably connected to the valve seat, and the free end of the one-way intake valve blocks the intake passage. 2. The air-floating piston according to claim 1, characterized in that: the piston body is provided with two air cavities, the two air cavities are arranged at intervals along the axial direction of the piston body, and the two air cavities The air cavities communicate with each other through the airway. 3. The air-floating piston according to claim 1, characterized in that: the main part of the one-way intake valve comprises a circular arc segment. 4. A cylinder, characterized in that it comprises the air-floating piston according to any one of claims 1-3.

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