CN112443994A

CN112443994A - Piston device for rotary Stirling refrigerator

Info

Publication number: CN112443994A
Application number: CN202011418216.1A
Authority: CN
Inventors: 叶重; 罗高乔; 王波; 朱魁章; 孙闽; 徐海峰
Original assignee: China Electronics Technology Group Corp No 16 Institute
Current assignee: China Electronics Technology Group Corp No 16 Institute; CETC 16 Research Institute
Priority date: 2020-12-07
Filing date: 2020-12-07
Publication date: 2021-03-05

Abstract

The invention discloses a piston device for a rotary Stirling refrigerator, which comprises a connecting rod and a piston, wherein the connecting rod is rotationally connected with the piston through a piston pin; the invention flexibly increases the motion freedom of the piston relative to the connecting rod by adding the ball joint between the connecting rod and the piston pin, so that the connecting rod and the piston can move in a self-adaptive relative motion manner in the operation process, the coaxiality requirement of the piston in the cylinder in linear reciprocating operation is ensured, the influence of the connecting rod on the lateral force of the piston in the planar motion process is reduced, the assembly precision requirement of the piston and the cylinder is reduced, the coaxiality requirement of the piston and the cylinder is ensured, and the service life of the piston and the cylinder is prolonged.

Description

Piston device for rotary Stirling refrigerator

Technical Field

The invention relates to the technical field of connecting rod pistons, in particular to a piston device for a rotary Stirling refrigerator.

Background

The stirling cryocooler is an active cryocooler adopting reverse stirling cycle, and is widely applied in the industrial and military fields, such as cooling of cryogenic electronic devices, infrared detectors, superconducting devices, etc., in missile guidance, infrared forward-view and night vision, thermal imagers, etc. The demand quantity of the Stirling refrigerating machines is increased rapidly, and higher requirements are also put forward on the service life of the refrigerating machines.

The stirling cryocooler is generally divided into a linear type and a rotary type according to the motion mode of the compressor, wherein the linear cryocooler is driven by a linear motor, and has the advantages of high reliability, low vibration noise and the like, but also has the defects of high technical difficulty, large volume and weight, high manufacturing cost, long debugging period and the like, and is mainly applied to aerospace and other occasions with strict requirements on reliability.

The rotary Stirling refrigerator is driven by a rotary motor, is supported by a crank connecting rod mechanism and a bearing, converts the rotary motion of the motor into the linear reciprocating motion of a single piston, has the characteristics of small volume, light weight and compact structure, is widely used in the infrared detectors in the military fields of airborne, missile-borne and the like, and provides a low-temperature environment for the infrared detector assembly. However, the existing piston has high requirement on assembly precision in the assembly process, and the problem that the lateral friction force of the piston to the cylinder is large, the working time of the piston is short and the like due to poor coaxiality of the piston and the cylinder in the working process

Disclosure of Invention

The invention aims to provide a piston device for a rotary Stirling refrigerator, which solves the problems in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

the piston comprises a connecting rod and a piston, wherein the connecting rod is rotatably connected with the piston through a piston pin, and the piston pin is movably connected with the connecting rod through a ball joint;

one end of the connecting rod, which is close to the piston, is provided with a step hole, the ball joint comprises a ball head which is rotatably connected in the step hole, and the ball head is sleeved on the piston pin.

As a further scheme of the invention: the connecting rod is internally provided with a circular boss, the circular boss is positioned at one end of the stepped hole, the connecting rod is internally provided with an annular groove, and the annular groove is positioned at one end, far away from the circular boss, of the stepped hole.

As a further scheme of the invention: the ball joint is positioned between the circular boss and the annular groove, and an elastic check ring for limiting is clamped in the annular groove.

As a further scheme of the invention: the ball head is rotatably connected between the concave spherical surfaces of the lower ball seat and the upper ball seat.

As a further scheme of the invention: and a wave-shaped gasket is arranged between the lower ball seat and the circular boss.

As a further scheme of the invention: the lower ball seat and the upper ball seat are made of polyimide materials, the surface smoothness of the lower ball seat and the upper ball seat is not more than Ra0.1, the ball head is made of bearing steel GGr15, the quenching hardness is not less than HRC70, and the surface smoothness is not more than Ra0.01.

As a further scheme of the invention: a ball head through hole is formed in the ball head, and the piston pin is inserted into the ball head through hole.

As a further scheme of the invention: the piston comprises a piston body with a cylindrical structure and a piston head arranged at one end of the piston body, wherein a piston blind hole used for accommodating the connecting rod is formed in one end, close to the connecting rod, of the piston body, and the piston blind hole and the piston body are coaxially arranged.

As a further scheme of the invention: and the piston body is provided with a piston through hole, and the piston pin is inserted in the piston through hole.

As a further scheme of the invention: and a V-shaped groove is formed in the periphery of the piston body.

Compared with the prior art, the invention has the beneficial effects that: according to the invention, the ball joint is additionally arranged between the connecting rod and the piston pin, so that the motion freedom degree of the piston relative to the connecting rod is flexibly increased, the connecting rod and the piston can perform self-adaptive relative motion in the operation process, the coaxiality requirement of the piston in linear reciprocating motion in the cylinder is ensured, the influence of the connecting rod on the lateral force of the piston in the plane motion process is reduced, the assembly precision requirement on the piston and the cylinder is reduced, the coaxiality requirement of the piston and the cylinder is ensured, and the service life of the piston and the cylinder is prolonged.

Drawings

FIG. 1 is a sectional view of the present embodiment;

FIG. 2 is a cross-sectional view of the connecting rod and ball joint of the present embodiment;

FIG. 3 is a sectional view of the piston according to the present embodiment;

FIG. 4 is a view showing the piston of the present embodiment biased to the left extreme position relative to the connecting rod;

fig. 5 shows the piston of the present embodiment biased to the right extreme position relative to the connecting rod.

In the figure: 1-connecting rod, 11-circular boss, 12-stepped hole, 13-annular groove, 2-ball joint, 21-wave-shaped gasket, 22-lower ball seat, 23-ball head, 24-upper ball seat, 25-elastic retainer ring, 26-ball head through hole, 3-piston pin, 4-piston, 41-piston head, 42-piston body, 43-piston through hole, 44-V-shaped groove and 45-piston blind hole.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-5, in an embodiment of the present invention, the connecting rod 1 and the piston 4 are included, the connecting rod 1 is rotatably connected to the piston 4 by a piston pin 3, and the piston pin 3 is movably connected to the connecting rod 1 by a ball joint 2.

The piston 4 comprises a piston body 42 with a cylindrical structure and a piston head 41 arranged at one end of the piston body 42, one end of the piston body 42 close to the connecting rod 1 is provided with a piston blind hole 45 for accommodating the connecting rod 1, the piston blind hole 45 and the piston body 42 are coaxially arranged, the piston body 42 is provided with a piston through hole 43, the piston pin 3 is inserted into the piston through hole 43, the periphery of the piston body 42 is provided with two V-shaped grooves 44, the two V-shaped grooves 44 are respectively positioned at two ends of the piston through hole 43, in addition, the piston 4 is made of high-speed tool steel materials and is subjected to quenching and hardening treatment.

One end of a connecting rod 1 close to a piston 4 is provided with a step hole 12, a circular boss 11 is arranged in the connecting rod 1, the circular boss 11 is positioned at one end of the step hole 12, an annular groove 13 is arranged in the connecting rod 1, the annular groove 13 is positioned at one end of the step hole 12 far away from the circular boss 11, a ball joint 2 comprises a ball head 23 rotatably connected in the step hole 12, a ball head through hole 26 is arranged in the ball head 23, a piston pin 3 is inserted in the ball head through hole 26, the ball head 23 is made of bearing steel GGr15, the quenching hardness is not less than HRC70, the surface smoothness is not more than Ra0.01, the ball joint 2 is positioned between the circular boss 11 and the annular groove 13, an elastic retainer ring 25 for limiting is clamped in the annular groove 13, a lower ball seat 22 and an upper ball seat 24 are arranged in the step hole 12, the lower ball seat 22 and the upper ball seat 24 are in concave spherical shapes, be equipped with wave form gasket 21 between ball seat 22 and the circular boss 11 down, the material of wave form gasket 21 is stainless steel 316L, and wave form structure comprises 3 ~ 4 ripples, for ball head 23 is hugged closely to ball seat 22 and last ball seat 24 down provides certain pretightning force, and ball seat 22, last ball seat 24 are polyimide material down, and ball seat 22, the smooth finish of the surface of last ball seat 24 are not more than Ra0.1 down.

Fig. 4 and 5 show the piston in the left and right extreme positions that may occur during operation of the connecting rod in this example. This embodiment is through a piston device, nimble increase the motion degree of freedom of the relative connecting rod of piston for connecting rod and piston can self-adaptation relative motion at the operation in-process, guarantee the straight reciprocating motion's of piston in the cylinder axiality requirement, reduce the connecting rod and reduce the lateral force influence that the plane motion in-process caused the piston, reduced the assembly precision requirement to piston and cylinder, and guaranteed the axiality requirement of piston and cylinder, prolonged the operating time of piston, improved the working life of refrigerator on the whole. The piston device is very suitable for being used in the field of taking the rotary Stirling refrigerator as a cold source in infrared detector assemblies in the military fields of airborne, missile-borne and the like.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A piston device for a rotary Stirling refrigerator comprises a connecting rod (1) and a piston (4), wherein the connecting rod (1) is rotatably connected with the piston (4) through a piston pin (3), and is characterized in that the piston pin (3) is movably connected with the connecting rod (1) through a ball joint (2);

one end of the connecting rod (1) close to the piston (4) is provided with a step hole (12), the ball joint (2) comprises a ball head (23) which is rotatably connected in the step hole (12), and the ball head (23) is sleeved on the piston pin (3).

2. A piston device for a rotary stirling cooler according to claim 1, wherein a circular boss (11) is provided in the connecting rod (1), the circular boss (11) being located at one end of the stepped bore (12), and an annular groove (13) is provided in the connecting rod (1), the annular groove (13) being located at one end of the stepped bore (12) remote from the circular boss (11).

3. A piston device for a rotating stirling cooler according to claim 2 wherein the ball joint (2) is located between the circular boss (11) and the annular groove (13), and a circlip (25) for limiting is snapped into the annular groove (13).

4. A piston device for a rotary stirling cooler according to claim 2, wherein the stepped bore (12) is provided with a lower ball seat (22) and an upper ball seat (24), the inner bores of the lower ball seat (22) and the upper ball seat (24) are of a concave spherical shape, the outer peripheries of the lower ball seat (22) and the upper ball seat (24) are of a cylindrical shape, and the ball head (23) is rotatably connected between the concave spherical surfaces of the lower ball seat (22) and the upper ball seat (24).

5. A piston device for a rotary Stirling refrigerator according to claim 4, wherein a corrugated gasket (21) is provided between said lower seat (22) and said circular boss (11).

6. A piston device for a rotary Stirling refrigerator according to claim 4, wherein the lower ball seat (22) and the upper ball seat (24) are made of polyimide, the surface finish of the lower ball seat (22) and the upper ball seat (24) is not more than Ra0.1, the ball head (23) is made of bearing steel GGr15, the quenching hardness is not less than HRC70, and the surface finish is not more than Ra0.01.

7. A piston device for a Stirling refrigerator of the rotary type according to claim 1, wherein a bulb through hole (26) is formed in said bulb (23), and said piston pin (3) is inserted into said bulb through hole (26).

8. A piston device for a rotary stirling cooler according to claim 1, wherein the piston (4) comprises a cylindrical piston body (42) and a piston head (41) arranged at one end of the piston body (42), one end of the piston body (42) close to the connecting rod (1) is provided with a blind piston hole (45) for accommodating the connecting rod, and the blind piston hole (45) is arranged coaxially with the piston body (42).

9. A piston device for a rotary Stirling refrigerator according to claim 8, wherein a piston through hole (43) is formed in the piston body (42), and the piston pin (3) is inserted into the piston through hole (43).

10. A piston device for a rotary Stirling refrigerator according to claim 8, wherein said piston body (42) is peripherally provided with V-grooves (44).