CN111946816A - Air Floating Pistons and Cylinders - Google Patents

Abstract

The invention discloses an air-floating piston and a cylinder, comprising a piston main body, wherein an air cavity is arranged in the piston main body, and the air cavity is controlled by a one-way intake valve to be closed or communicated with the outside of the piston main body; the The piston main body is provided with an installation hole, and the installation hole communicates with the air cavity and the outside of the piston main body along the radial direction of the piston main body; a throttle plug is assembled in the installation hole; The choke plug is provided with a through hole along its axial direction, a capillary tube is fixed in the through hole, and one end of the capillary tube extends out of 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 the air-floating piston and the cylinder of the present invention, a capillary tube with an inner diameter of 0.05-0.2 mm is used to replace the throttling slit directly in the throttling plug, the capillary tube greatly reduces the requirement of the air-floating piston on the machining accuracy, the processing cost is low, and the assembly is difficult Small, and has a high air film stiffness.

Description

Air Floating Pistons and Cylinders

technical field

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

Background technique

The small regenerative cryogenic refrigerator is usually driven by a linear motor, and the gap sealing (unilateral gap 12-25un) technology is used between the piston and the cylinder. The high-pressure gas film in the air gap with the cylinder provides sufficient radial support for the piston. The traditional air-floating piston processes 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 velocity drops sharply, and the kinetic energy is converted into the pressure supporting the piston. potential energy, thereby 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 machining 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 batches Production.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an air-floating piston and a cylinder, which can reduce the requirement of machining precision, have low machining cost, small assembly difficulty and high air film rigidity.

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

A piston main body, an air cavity is arranged in the piston main body, and the air cavity is controlled by a one-way 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, and the mounting hole is along the The radial direction of the piston body communicates with the air chamber and the outside of the piston body;

a throttle plug, which is assembled in the mounting hole;

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

In a preferred embodiment of the present invention, it further includes that the 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 spirally 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 is matched with the inner diameter of the through hole, and the two are fixed by gluing.

In a preferred embodiment of the present invention, when the throttle plug is assembled in the installation hole, the end cap of the throttle plug is lower than the orifice of the installation hole, and the hole of the installation hole The diameter of the mouth is 1.5-2.5 times the outer diameter of the end cap of the throttle plug.

In a preferred embodiment of the present invention, it further comprises that the throttle 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.

In a preferred embodiment of the present invention, it further includes 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 pass through the air passage. Connected.

In a preferred embodiment of the present invention, a valve seat is further provided in the piston body, the valve seat and the piston body are in an interference fit to close the air cavity, and the valve seat is provided with a valve seat that communicates with the air The cavity and the intake passage outside the piston body, 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.

In a preferred embodiment of the present invention, the main body portion of the one-way intake valve further includes a circular 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:

In the air-floating piston and cylinder of the present invention, a capillary tube with an inner diameter of 0.05-0.2 mm is used instead of directly processing a throttling slit in the throttling plug, and the throttling and stabilizing effect of the capillary tube is used, when the gas is output from the installation hole, the gas velocity suddenly increases The kinetic energy is all converted into the pressure potential energy of the supporting 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, resulting in low processing costs and assembly difficulty. stiffness.

Description of drawings

1 is a schematic structural diagram of an air-floating piston in a preferred embodiment of the present invention;

Fig. 2 is the axial sectional schematic diagram of the air flotation piston shown in Fig. 1;

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

4 is a schematic structural diagram of a choke plug in a preferred embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a choke plug in another embodiment of the present invention.

Description of the labels in the figure:

1-cylinder, 2-piston body, 4-valve seat, 6-air chamber, 8-check intake valve, 10-installation hole, 12-throttle plug, 14-through hole, 16-capillary tube, 18-90 °Bending part, 20-end cap, 22-screw, 24-head, 26-inlet passage, 27-inlet, 28-circular segment, 30-air passage, 32-cylindrical groove, 34 -Threaded hole.

Detailed ways

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

Example

The embodiment of the present invention discloses an air-floating piston. Referring to FIGS. 1 to 3 , the air-floating piston includes a piston body 2 and a throttle plug 12 . The piston body 2 is provided with an air cavity 6 , which passes through the air cavity 6 . The one-way intake valve 8 is controlled to be closed or communicated with 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 in an interference fit to close the space. In the air chamber 6, the valve seat 4 is provided with an intake passage 26 that communicates the air chamber 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 cavity 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 cavity 6 through the air intake passage 26; When the external pressure of the piston main body 2 is lower than the pressure of the air cavity 6 , the one-way intake valve 8 blocks the air intake passage 26 to prevent the gas outside the piston main body 2 from entering the air cavity 6 .

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

Figure 3 shows the 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 air pushes open the one-way intake valve 8, and the external high-pressure gas It enters into the air cavity 6 through the intake passage 26 in the valve seat 4, and then is sprayed from the orifice of the installation hole 10 through the throttling and pressure stabilization effect of the capillary 16, and is evenly sprayed to the inner surface of the cylinder; based on fluid mechanics Bernoulli's principle, when the gas is output from the orifice of the mounting hole 10, the gas velocity drops sharply, and the kinetic energy is all converted into the pressure potential energy supporting the piston, thereby providing sufficient radial support for the piston and achieving 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 traditional air flotation or sprinkler throttling slit. The throttling slit, the air-floating piston of the embodiment of the present invention, the processing difficulty of processing the through hole 14 on the throttling plug 12 that is compatible with the capillary 16 is greatly reduced, and the processing accuracy requirements of the through hole 14 are also greatly reduced, so that the The processing cost of the air-floating piston is reduced accordingly. On the other hand, for 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 relatively difficult. In the embodiment of the present invention, the capillary 16 is used instead, which directly overcomes the problem of high assembly difficulty, brings the technical advantage of less assembly difficulty, and has higher air film rigidity, providing sufficient radial support for the piston.

Specifically, the capillary 16 and the through hole 14 are fixed by gluing. In an implementation scheme of gluing and fixing, a small amount of clear water-like epoxy glue is dipped with a very fine brush and evenly coated on the through hole 14 of the choke plug 12. The inner wall that is in contact with the capillary 16, and then insert the capillary 16 into the through hole 14. When inserting the capillary 16, the end of the inserted capillary 16 is controlled to be lower than the orifice of the through hole 14. Before the glue dries, use an alcohol cotton ball at the hole position of the through hole 14. Wipe up any spilled glue. In order to prevent the capillary 16 and the through hole 14 from clogging the inner diameter of the capillary 16 during the gluing process, as shown in FIG.

The throttle plug 12 includes a screw 22 and an end cap 20. The throttle plug 12 is threadedly fitted into the mounting hole 10, and one end away from the end cap 20 protrudes from the mounting hole 10 to extend. inside the air cavity 6 . Specifically, the mounting hole 10 includes a cylindrical groove 32 located at the orifice and a threaded hole 34 communicating with it. When the throttle plug 12 is assembled in the mounting hole 10, the screw thread 22 is tightly fitted with the threaded hole 34, 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 gas pressure P ejected from the through hole 14 is constant, the air buoyancy force F 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 , 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 air buoyancy will be uneven; Pressure drop and 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 orifice of the installation hole 10 . , and the diameter of the orifice of the mounting hole 10 (ie the notch of the cylindrical groove 32 ) is 1.5-2.5 times the outer diameter of the end cap 20 of the throttle plug 12 .

Referring to FIGS. 3 and 4 , the end of the capillary 16 extending into the air cavity 6 has a 90° bent 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 cavity 6 .

It can be understood that, in order to equalize the radial bearing capacity of the piston, the piston body 2 is provided with a plurality of the mounting holes 10 along the circumferential direction (for example, four mounting holes 10 are arranged at intervals along the circumferential direction), corresponding to each of the mounting holes 10. Each of the mounting holes 10 is provided with one of the throttle plugs 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 with each other through the air passage 30 . Specifically, when one air chamber 6 is changed to two air chambers 6, the piston body 2 is provided with a head 24, and the head 24 is in an interference fit with the piston body 2. At this time, the head 24 and the valve The seat 4 is fitted to divide the interior of the piston body 2 into two air cavities 6 arranged at an axial interval. The piston main body 2 is provided with a plurality of the mounting holes 10 corresponding to each air cavity 6, and each of the mounting holes is provided with one of the throttle plugs 12. Based on the above principle description, two air cavities 6 can be provided. Further evens out 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 (ie, its free end) blocks the intake passage 26, and when the external pressure is higher than the pressure of the air chamber 6 , the one-way intake valve 8 swings with its connection point with the valve seat 4 as the fulcrum (or the root of the one-way intake valve 8). Referring to FIG. 1, in the technical solution of this embodiment, the one-way intake valve The main body of the air valve 8 includes a circular arc section 28, and the circular arc section 28 of the one-way intake valve 8 can buffer the force on the root of the one-way intake valve 8 when it swings, so that the one-way intake valve 8 is not easily affected. Broken to extend the service life of the one-way intake valve 8.

In another embodiment of the present invention, for the application of the high inlet pressure of the air chamber 6, the length of the capillary 16 needs to be increased to further reduce the pressure of the gas ejected from the through hole 14. At the same time, the longer capillary 16 also The pressure stabilization 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 set. Under the limited length of the capillary 16, the spiral arrangement has greater resistance along the path than the straight arrangement, so that the throttling and voltage stabilization effect of the capillary 16 is more significant. On the other hand, when the length of the capillary 16 is increased by means of a helical arrangement to be applied to a scenario with a high intake pressure, it is beneficial to reduce the diameter of the air flotation piston compared to the straight arrangement. Based on the same principle, the capillary 16 is used to replace the traditional gas The throttling slit of the float piston can reduce the diameter of the air float 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 includes all the technical effects of the air-floating piston, and can also realize frictionless motion between the cylinder and the piston, thereby 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 is subject to the claims.

Claims (10)

1. An air-floating piston, comprising, A piston main body, an air cavity is arranged in the piston main body, and the air cavity is controlled by a one-way 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, and the mounting hole is along the The radial direction of the piston body communicates with the air chamber and the outside of the piston body; a throttle plug, which is assembled in the mounting hole; It is characterized in that: the choke plug is provided with a through hole along its axial direction, a capillary tube is fixed in the through hole, and one end of the capillary tube extends out of the through hole and extends into the air cavity, so that the The air cavity is also communicated with the outside of the piston body through the capillary. 2 . The air-floating piston according to claim 1 , wherein the 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 The air inlet of the air chamber. 3 . The air flotation piston according to claim 1 or 2 , wherein the part of the capillary extending into the air cavity is spirally arranged along the outer wall of the throttle plug. 4 . 4 . The air-floating piston of claim 1 , wherein the outer diameter of the capillary tube matches the inner diameter of the through hole, and the two are fixed by gluing. 5 . 5. The air-floating piston of claim 1, wherein when the throttle plug is assembled in the installation hole, the end cap of the throttle plug is lower than the orifice of the installation hole, and The diameter of the orifice of the installation hole is 1.5-2.5 times the outer diameter of the end cap of the throttle plug. 6 . The air-floating piston according to claim 5 , wherein the throttle plug is threadedly fitted in the mounting hole, and its end away from the end cap extends out of the mounting hole and extends to the mounting hole. 7 . inside the air cavity. 7 . The air-floating piston according to claim 1 , wherein two air cavities are provided in the piston body, the two air cavities are arranged at intervals along the axial direction of the piston body, and the two air cavities are arranged in the piston body. 8 . The air cavities communicate through the airway. 8 . The air-floating piston according to claim 1 , wherein a valve seat is provided in the piston body, the valve seat and the piston body are in interference fit to close the air cavity, and the valve seat is inside the valve seat. 9 . There is an intake passage communicating with the air chamber and the outside of the piston body, 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. 9 . The air-floating piston of claim 8 , wherein the main body portion of the one-way intake valve comprises a circular arc segment. 10 . 10. A cylinder, characterized in that it comprises the air-floating piston according to any one of claims 1 to 9.

Images