An expander and stirling cryocooler

Abstract

The utility model belongs to refrigerating machine technical field, concretely provides an expander, including cold finger protection cylinder and the base connected in cold finger one end, the cold finger is inlaid with the cold accumulator of sliding, the cavity that base and cold finger enclose forms is equipped with the guide piston, one end of guide piston is fixedly connected with base, the other end sliding sleeve joint has guide cylinder, guide cylinder with cold accumulator is connected. The utility model provides this kind of expander of improvement guide piston and guide cylinder's relative motion structure, make guide cylinder move forward and backward relative to piston after being subjected to gas force, carry out gas compression and expansion to refrigerate, guide piston can be integrated with expander base and process, reduce processing cost. Simultaneously still can join magnetic force spring subassembly, replace leaf spring in axial direction and carry out the location, can effectively reduce the risk of cylinder collision.

Description

Technical Field

[0001] This utility model belongs to the field of refrigeration technology, specifically relating to an expander and a Stirling refrigeration machine. Background Technology

[0002] Linear Stirling refrigerators are widely used in civilian and military equipment such as infrared thermal imagers, infrared forward-looking and night vision devices, missile guidance, and space applications. The expander, as the core component of the Stirling refrigerator, is the component that realizes the cooling effect.

[0003] Conventional expanders use leaf springs or column springs to connect with the guide piston. When subjected to gas force, the piston moves axially back and forth, and the corresponding leaf springs or column springs can limit the displacement. However, when the gas force is greater than the spring's restoring force, the piston will collide with the cylinder, thus affecting the life of the parts. Utility Model Content

[0004] The purpose of this invention is to overcome the problem of cylinder collision that easily occurs when existing expanders use mechanical springs for limiting.

[0005] Therefore, this utility model provides an expander, including a cold finger and a base connected to one end of a protective cylinder for the cold finger; a cold accumulator is slidably disposed inside the cold finger; a guide piston is disposed in the cavity formed by the base and the protective cylinder for the cold finger; one end of the guide piston is fixedly connected to the base, and the other end is slidably sleeved with a guide cylinder; the guide cylinder is connected to the cold accumulator.

[0006] Specifically, the expander also includes a magnetic spring assembly; the magnetic spring assembly is installed in the cavity formed by the base and the cold finger; the magnetic spring assembly is used to generate a magnetic force to limit the excessive axial movement of the guide cylinder.

[0007] Specifically, the aforementioned magnetic spring assembly includes a first magnetic component and a second magnetic component; the first magnetic component is mounted on the base; the second magnetic component is mounted on the guide cylinder; both the first magnetic component and the second magnetic component are magnetized radially along the guide piston and in the same magnetization direction, or both the first magnetic component and the second magnetic component are magnetized axially along the guide piston and in opposite magnetization directions.

[0008] Specifically, an annular protrusion is provided inside the base; the guide piston is fixed inside the annular protrusion, and one end extends out of the annular protrusion and is connected to the guide cylinder; the first magnetic component is installed on the annular protrusion.

[0009] Specifically, the aforementioned magnetic spring assembly further includes a third magnetic component; the third magnetic component is installed inside the cold finger protection cylinder; the third magnetic component and the second magnetic component are both magnetized radially along the guide piston and in the same magnetization direction, or the third magnetic component and the second magnetic component are both magnetized axially along the guide piston and in opposite magnetization directions.

[0010] Specifically, the first magnetic component, the second magnetic component, and the third magnetic component are all annular and coaxially arranged along the length of the guide piston.

[0011] Specifically, the aforementioned guide piston is integrally formed with the base.

[0012] Specifically, the aforementioned guide cylinder is coaxially sleeved and fixed to the cold accumulator and is internally connected.

[0013] Specifically, the aforementioned cold finger includes a cold finger protection cylinder and a cold finger cylinder connected together; the cold finger protection cylinder has an air intake channel communicating with the internal cavity, and the guide cylinder has an air intake hole communicating with the air intake channel and the interior of the guide cylinder.

[0014] This invention also provides a Stirling refrigerator, including the aforementioned expander.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0016] The expander provided by this utility model improves the relative motion structure between the guide piston and the guide cylinder. This allows the guide cylinder to move back and forth relative to the piston under gas force, compressing and expanding the gas for cooling. The guide piston can be integrally machined with the expander base, reducing manufacturing costs. Furthermore, the addition of a magnetic spring assembly replaces the leaf spring for axial positioning, effectively reducing the risk of cylinder collision.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of the expander provided by this utility model.

[0019] Figure 2 This is a schematic diagram of the base structure of the expander provided by this utility model.

[0020] Explanation of reference numerals in the attached drawings: 1. Base; 101. Annular protrusion; 102. Connecting flange; 2. Cold finger protection cylinder; 201. Air inlet passage; 3. Guide piston; 4. Guide cylinder; 5. First magnetic component; 6. Second magnetic component; 7. Third magnetic component; 8. Cold accumulator; 9. Cold finger cylinder. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0022] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0024] Reference Figure 1 This utility model provides an expander, including a cold finger protection cylinder 2 and a base 1 connected to one end of the cold finger protection cylinder 2; a cold accumulator 8 is slidably disposed inside the cold finger; a guide piston 3 is disposed in the cavity formed by the base 1 and the cold finger protection cylinder 2; one end of the guide piston 3 is fixedly connected to the base 1, and the other end is slidably sleeved with a guide cylinder 4, preferably with a clearance fit between the guide piston 3 and the guide cylinder 4; the guide cylinder 4 is connected to the cold accumulator 8. During operation, the guide cylinder 4 reciprocates relative to the guide piston 3 to generate a cooling effect.

[0025] Furthermore, the expander also includes a magnetic spring assembly; the magnetic spring assembly is installed in the cavity formed by the base 1 and the cold finger; the magnetic spring assembly is used to generate a magnetic force to limit the excessive axial movement of the guide cylinder 4. When the guide cylinder 4 moves, the magnetic spring assembly generates a magnetic force and applies it to the guide cylinder 4, limiting the range of movement of the guide cylinder 4 and preventing cylinder collision due to excessive movement.

[0026] Specifically, the magnetic spring assembly includes a first magnetic element 5 and a second magnetic element 6. The first magnetic element 5 is mounted on the base 1; the second magnetic element 6 is mounted on the guide cylinder 4. Both the first magnetic element 5 and the second magnetic element 6 are magnetized radially along the guide piston 3 in the same direction, or both are magnetized axially along the guide piston 3 in opposite directions. When the guide cylinder 4 is in its initial state, the first magnetic element 5 and the second magnetic element 6 are in equilibrium. When the guide cylinder 4 moves towards the base 1, a repulsive force is generated between the first magnetic element 5 and the second magnetic element 6. As the distance between them decreases, the repulsive force increases, effectively reducing the risk of cylinder collision.

[0027] Preferred, such as Figure 2 As shown, an annular protrusion 101 is provided inside the base 1 to facilitate the installation of the first magnetic component 5. One end of the guide piston 3 is fixed inside the annular protrusion 101, and the other end extends out of the annular protrusion 101 and is connected to the guide cylinder 4; the first magnetic component 5 is installed on the annular protrusion 101, so that when the guide cylinder 4 is sleeved on the guide piston 3, the first magnetic component 5 and the second magnetic component 6 are distributed along the axial direction of the guide piston 3.

[0028] Furthermore, the magnetic spring assembly also includes a third magnetic element 7 arranged along the length of the guide piston 3; the third magnetic element 7 is installed inside the cold finger; the third magnetic element 7 and the second magnetic element 6 are both magnetized radially along the guide piston 3 and in the same magnetization direction, or the third magnetic element 7 and the second magnetic element 6 are both magnetized axially along the guide piston 3 and in opposite magnetization directions. The first magnetic element 5, the second magnetic element 6, and the third magnetic element 7 are all permanent magnets (such as magnets, magnetic rings, etc.). When the guide cylinder 4 and the second magnetic element 6 are in their initial positions, the resultant magnetic force generated by the first magnetic element 5 and the third magnetic element 7 on both sides of the second magnetic element 6 is zero. When the guide cylinder 4 drives the second magnetic element 6 to reciprocate synchronously, the second magnetic element 6 deviates from its initial position, and the balance between the first magnetic element 5, the third magnetic element 7, and the second magnetic element 6 is broken. The repulsive force applied on both sides produces a restoring effect similar to a mechanical spring, preventing the guide cylinder 4 from moving excessively and hitting the cylinder. The magnitude of the magnetic force can be adjusted by adjusting the size and material of the first magnetic element 5, the second magnetic element 6, and the third magnetic element 7.

[0029] The first magnetic component 5, the second magnetic component 6, and the third magnetic component 7 are preferably all in a ring shape and arranged coaxially along the length of the guide piston 3. The repulsive force direction is parallel to the movement direction of the guide cylinder 4 (the length direction of the guide piston 3) to avoid uneven force distribution and deviation of the guide cylinder 4 during movement.

[0030] In a more detailed embodiment, the first magnetic element 5 and the third magnetic element 7 are both magnetic ring structures, and the second magnetic element 6 is a ring-shaped magnet, such as... Figure 1As shown, the magnet is fixed to the outside of the guide cylinder 4 by bonding or other feasible methods. Two magnetic rings are located at both ends of the magnet and are respectively connected and fixed to the base 1 or cold-fin. After the magnetic rings and magnet are magnetized, when the guide cylinder 4 moves axially, it drives the magnet to move along the magnetic ring on one side of the axis. The magnetic ring on this side and the magnet will generate a repulsive force. As the moving distance increases, the repulsive force will become larger and larger, which can effectively reduce the risk of cylinder collision.

[0031] Furthermore, the guide piston 3 is integrally formed with the base 1, which can reduce processing costs.

[0032] In one embodiment, specifically, the guide cylinder 4 is coaxially sleeved and fixed to the cold accumulator 8 and internally connected. The guide cylinder 4 drives the cold accumulator 8 to reciprocate within the cold finger to generate a cooling effect.

[0033] Furthermore, the cold finger includes a cold finger protection cylinder 2 and a cold finger cylinder 9. The cold finger protection cylinder 2 is connected to the base 1, and the cold finger cylinder 9 is located at the end of the cold finger protection cylinder 2 away from the base 1. The cold finger protection cylinder 2 has an air inlet channel 201 communicating with the internal cavity, and the guide cylinder 4 has an air inlet hole communicating with the air inlet channel 201 and the interior of the guide cylinder 4. Gas enters the cavity formed by the base 1 and the cold finger protection cylinder 2 through the air inlet channel 201, causing the guide cylinder 4 located within it to be subjected to the force of the flowing gas, resulting in axial reciprocating motion. The cold finger cylinder 9 can be a cylindrical shape with openings at both ends; one end is sealed to the cold finger protection cylinder 2, and the other end can be sealed with a cold head. The third magnetic component 7 is preferably fixed inside the cold finger protection cylinder 2.

[0034] Specifically, the cold accumulator 8 includes a cold accumulator shell and a cold accumulator mesh filled inside the cold accumulator shell; the guide cylinder 4 is connected to one end of the cold accumulator shell. The outer shell of the cold accumulator 8 is clearance-fitted with the cold finger cylinder 9 and reciprocates within the cold finger cylinder 9.

[0035] Preferably, the cold finger cylinder 9, the cold accumulator 8, the guide cylinder 4, and the guide piston 3 are arranged coaxially. The cold accumulator 8, the guide cylinder 4, and the guide piston 3 constitute a pushing assembly.

[0036] Furthermore, such as Figure 2 As shown, a connecting flange 102 is provided on the base 1; the base 1 is connected to the cold finger protection cylinder 2 through the connecting flange 102.

[0037] Example 1: This example provides an expander, including a base 1, a cold finger protection cylinder 2, a cold finger cylinder 9, a guide piston 3, a guide cylinder 4, a magnetic spring assembly, and a cold accumulator 8;

[0038] An annular protrusion 101 is provided inside the base 1; a guide piston 3 is provided inside the annular protrusion 101, and one end extends out of the annular protrusion 101; the guide piston 3, the annular protrusion 101 and the base 1 are integrally formed.

[0039] One end of the cold finger protection cylinder 2 is sealed to the base 1, and the other end is sealed to the cold finger cylinder 9, forming a cavity inside the three. The cold finger protection cylinder 2 is provided with an air inlet channel 201 that communicates with the internal cavity, and the guide cylinder 4 is provided with an air inlet hole that communicates with the air inlet channel 201 and the interior of the guide cylinder 4.

[0040] The guide piston 3, guide cylinder 4, magnetic spring assembly and cold accumulator 8 are all located in the cavity, and the cold finger cylinder 9, cold accumulator 8, guide cylinder 4 and guide piston 3 are coaxially arranged; the guide cylinder 4 is slidably sleeved on the outside of the guide piston 3, and the guide piston 3 and guide cylinder 4 are clearance-fitted; one end of the cold accumulator 8 is connected to the end of the guide cylinder 4 away from the guide piston 3, and the other end of the cold accumulator 8 extends into the interior of the cold finger cylinder 9;

[0041] The magnetic spring assembly includes a first magnetic element 5, a second magnetic element 6, and a third magnetic element 7 arranged sequentially along the length of the guide piston 3. The first magnetic element 5 is a magnetic ring, which is mounted on the annular protrusion 101 of the base 1. The second magnetic element 6 is an annular magnet, which is bonded to the outer wall of the guide cylinder 4. The third magnetic element 7 is also a magnetic ring, which is installed inside the cold finger protection cylinder 2. The magnetic ring and the magnet are both radially magnetized and the magnetization direction is the same. The first magnetic element 5, the second magnetic element 6, and the third magnetic element 7 are arranged coaxially along the length of the guide piston 3.

[0042] When the guide cylinder 4 and the second magnetic component 6 are in their initial positions, the combined magnetic force exerted by the first magnetic component 5 and the third magnetic component 7 on the second magnetic component 6 on both sides is zero. When the guide cylinder 4 is subjected to the force of gas flowing in from the intake channel 201, it cooperates with the guide piston 3 to drive the second magnetic component 6 and the coolant accumulator 8 to reciprocate axially, generating a cooling effect. At this time, the second magnetic component 6 (magnet) deviates from its initial position, and the first magnetic component 5 or the third magnetic component 7 will generate a repulsive force with the second magnetic component 6, thus producing a restoring effect similar to a mechanical spring. When the guide cylinder 4 moves to one side, the magnetic ring and the magnet on that side will generate a repulsive force. As the moving distance increases, the repulsive force will become larger and larger, which can effectively reduce the risk of cylinder collision.

[0043] The above examples are merely illustrative of this utility model and do not constitute a limitation on the scope of protection of this utility model. All designs that are the same as or similar to this utility model are within the scope of protection of this utility model.

Claims

1. An expander, characterized in that: It includes a cold finger and a base (1) connected to one end of the cold finger; a cold accumulator (8) is slidably disposed inside the cold finger; a guide piston (3) is provided in the cavity formed by the base (1) and the cold finger; one end of the guide piston (3) is fixedly connected to the base (1), and the other end is slidably sleeved with a guide cylinder (4); the guide cylinder (4) is connected to the cold accumulator (8).

2. The expander as described in claim 1, characterized in that: It also includes a magnetic spring assembly; the magnetic spring assembly is installed in the cavity formed by the base (1) and the cold finger; the magnetic spring assembly is used to generate a magnetic force to limit the excessive axial movement of the guide cylinder (4).

3. The expander as described in claim 2, characterized in that: The magnetic spring assembly includes a first magnetic element (5) and a second magnetic element (6); the first magnetic element (5) is mounted on the base (1); the second magnetic element (6) is mounted on the guide cylinder (4); the first magnetic element (5) and the second magnetic element (6) are both magnetized radially along the guide piston (3) and the magnetization direction is the same, or the first magnetic element (5) and the second magnetic element (6) are both magnetized axially along the guide piston (3) and the magnetization direction is opposite.

4. The expander as described in claim 3, characterized in that: The base (1) is provided with an annular protrusion (101); the guide piston (3) is fixed inside the annular protrusion (101), and one end extends out of the annular protrusion (101) and is connected to the guide cylinder (4); the first magnetic component (5) is installed on the annular protrusion (101).

5. The expander as described in claim 3, characterized in that: The magnetic spring assembly further includes a third magnetic element (7); the third magnetic element (7) is installed inside the cold finger; the third magnetic element (7) and the second magnetic element (6) are both magnetized radially along the guide piston (3) and the magnetization direction is the same, or the third magnetic element (7) and the second magnetic element (6) are both magnetized axially along the guide piston (3) and the magnetization direction is opposite.

6. The expander as described in claim 5, characterized in that: The first magnetic component (5), the second magnetic component (6), and the third magnetic component (7) are all annular and coaxially arranged along the length of the guide piston (3).

7. The expander as described in claim 1, characterized in that: The guide piston (3) is integrally formed with the base (1).

8. The expander as described in claim 1, characterized in that: The guide cylinder (4) is coaxially sleeved and fixed with the accumulator (8) and internally connected.

9. The expander as described in claim 1, characterized in that: The cold finger includes a cold finger protection cylinder (2) and a cold finger cylinder (9) connected to each other; the cold finger protection cylinder (2) is provided with an air inlet channel (201) communicating with the internal cavity, and the guide cylinder (4) is provided with an air inlet hole communicating with the air inlet channel (201) and the interior of the guide cylinder (4).

10. A Stirling refrigerator, characterized in that, Includes the expander as described in any one of claims 1-9.

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