A push piston assembly for Stirling refrigerator

Abstract

The invention relates to a push piston assembly for a Stirling refrigerator, wherein a push air flotation inner sleeve is fixed on the inner side of a guide piston and has a first gap with the guide piston; a valve plate component is provided at a position on the inner side of the guide piston corresponding to an air intake hole; a porous medium component is provided at a position of the push air flotation inner sleeve opposite to the first gap, and the porous medium component is connected to a first micro-annular groove located around the guide piston through a first small hole on the push air flotation inner sleeve; a second micro-annular groove is provided at a position near the first micro-annular groove around the guide piston, and a second gap is provided between the area between the first micro-annular groove and the second micro-annular groove and the guide piston, and the first micro-annular groove and the second micro-annular groove are connected through the second gap; by analogy, the Nth micro-annular groove and the N+1th micro-annular groove are connected through the N+1th gap; a second small hole is provided on the guide piston at the position where the N+1th micro-annular groove is located and overlaps with part of the N+1th micro-annular groove, and the second small hole is connected to the outside of the side wall of the guide piston.

Description

Technical Field

[0001] The invention relates to a push piston assembly for a Stirling refrigerator and a Stirling refrigerator, belonging to the technical field of low-temperature refrigeration. Background Art

[0002] In order to achieve the requirements of long life and high reliability, the piston and cylinder of a traditional Stirling refrigerator need to maintain a sealed gap and no contact. An air bearing structure is usually used to keep the piston suspended when moving in the cylinder.

[0003] As published on March 8, 2022, a Chinese patent document with publication number CN215983307U discloses a piston for a Stirling refrigerator, in which a porous medium throttle is used in the push piston part for throttling and a support lining is used inside the piston for insulation and support.

[0004] Its air bearing adopts a throttle structure, which makes the piston more complicated. One piston generally adopts multiple (4~16) throttles, and the gas flow detection and assembly of the same batch of throttles used by the piston are required to ensure the consistency of the gas flow rate in each outlet direction. The use of multiple porous medium throttles increases the processing cost and detection cost, and increases the difficulty of assembly, prolongs the assembly time of the refrigerator. At the same time, the reliability of the throttle screw cannot be guaranteed. This structure is not suitable for mass production. Although the support lining can insulate, the insulation effect is not good. The use of the support lining increases the weight of the piston and the complexity of processing and assembly. In addition, the selection of the lining material and the heat conduction characteristics may also lead to uneven temperature distribution, further affecting the cooling effect. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a push piston assembly of a Stirling refrigerator, which uses only a metal porous medium to control the inlet and outlet air flow rates. After the air flow enters the microgroove, it is evenly distributed and throttled by the small holes on the surface of the piston. Compared with the throttle, the air outlet is more uniform, the flow consistency is good, the control cost is low, the assembly yield is high, and the assembly time is short; the push piston is filled with soft cotton, and the total mass of the piston assembly can be flexibly adjusted to isolate the heat exchange between the guide piston and the push piston. Compared with the support liner (the prior art cited in the background technology), the isolation is better and the cost is lower. At the same time, the difficulty of assembling the coaxiality of the push piston and the guide piston is further reduced, thereby improving the assembly yield of the component and stabilizing the performance consistency of the refrigerator.

[0006] The present invention adopts the following technical solutions:

[0007] A push piston assembly for a Stirling refrigerator, comprising a guide piston rod 1, a guide piston 2, a push piston 7, and a push air flotation inner sleeve 5, wherein the push air flotation inner sleeve 5 is fixed to the inner side of the guide piston 2 and has a first gap with the guide piston 2; a valve plate component is provided at a portion of the inner side of the guide piston 2 corresponding to the air intake hole; a porous medium component 6 is provided at the push air flotation inner sleeve 5 facing the first gap, and the porous medium component is connected to a first micro-annular groove 8 located around the guide piston 2 through a first small hole on the push air flotation inner sleeve 5 ; A second micro-annular groove 9 is provided near the first micro-annular groove around the guide piston 2, and a second gap of setting is provided between the region between the first micro-annular groove 8 and the second micro-annular groove 9 and the guide piston 2, and the first micro-annular groove 8 and the second micro-annular groove 9 are communicated with each other through the second gap; By analogy, the Nth micro-annular groove and the N+1th micro-annular groove are communicated with each other through the N+1th gap, N≥1; A second small hole which overlaps with the N+1th micro-annular groove part is provided on the guide piston 2 at the position of the N+1th micro-annular groove, and the second small hole is communicated with the outside of the side wall of the guide piston 2;

[0008] Preferably, the push piston 7 is fixed to the guide piston 2 and forms an internal space, in which a flexible material is placed, and the flexible material is used to adjust the counterweight of the push piston assembly for the Stirling refrigerator and isolate the heat exchange between the guide piston and the push piston.

[0009] Furthermore, the flexible material is silk cotton, which is weighed to ensure that the total weight of the push piston assembly is controlled within an error range of 0.1 g, and then the push piston 7 is bonded to the guide piston assembly with glue.

[0010] Preferably, the volume of the first micro-annular groove 8 is larger than that of the second micro-annular groove 9 .

[0011] Preferably, the porous medium component 6 is made of metal.

[0012] Preferably, the second small hole has an enlarged hole at the end thereof, and the number and rows of the second small holes arranged along the circumference of the guide piston 2 are adjusted according to the length of the guide piston 2 .

[0013] Preferably, the push air-floating inner bushing 5 is coaxially fixedly connected to the guide piston rod 1 via a short shaft, and the short shaft passes through the guide piston 2 and is fixed to the guide piston 2 via a nut.

[0014] Preferably, a coaxial hole is machined at the center of the surface of the guide piston 2, and the guide piston rod 1 is coaxially assembled with the guide piston 2 through the coaxial hole. The two are connected by screws, and the screws on the inner wall of the guide piston 2 are fixed with nuts, and the contact between the nut and the guide piston 2 is sealed with glue to prevent leakage of high-pressure gas inside the guide piston 2.

[0015] Preferably, the valve plate component includes a valve plate seat 3 and a valve plate 4, the valve plate seat 3 is connected to the guide piston 2 by screws, and the valve plate component has the function of a one-way valve.

[0016] Preferably, O-rings are placed in the upper and lower grooves of the push-floating inner sleeve 5 for sealing; the push-floating inner sleeve 5 is connected to the guide piston assembly with screws and fastened with nuts, and the contact points between the upper and lower surfaces of the push-floating inner sleeve 5 and the nuts are sealed with glue to prevent air leakage.

[0017] The beneficial effects of the present invention are:

[0018] 1) Simplify the structure and reduce costs: By improving the throttle design in the push piston assembly, the traditional complex throttle structure is eliminated, and metal porous media and micro grooves are used for airflow throttling. Compared with the traditional throttle throttling method, this design not only reduces the complexity of the piston structure, but also effectively reduces the manufacturing cost, while reducing the weight of the piston assembly, making the movement of the piston in the low-temperature refrigerator Stirling refrigerator more stable, which helps to improve the overall refrigeration efficiency. Although the traditional support lining (background technology citation) can provide a certain insulation effect, due to the limited insulation effect and increased structural complexity and mass, the use of silk cotton to fill the push piston can reduce the mass of the piston and the insulation effect of the push piston and the guide piston will be better than the support lining.

[0019] 2) Improved thermal insulation and weight control: The present invention fills the push piston with a flexible material (silk floss), which not only has good thermal insulation properties, but also significantly reduces the weight of the piston. Compared with traditional support liners, silk floss is lighter, and due to its uniform structure and good thermal insulation ability, it effectively blocks the heat exchange between the push piston and the guide piston, improving the cooling effect of the system. At the same time, the use of silk floss also simplifies the piston structure, so that the overall weight of the piston assembly is controlled within the range of ±0.1g, achieving precise quality control. Through precise weight allocation, the piston maintains dynamic balance during operation, thereby reducing unnecessary energy loss and improving the operating stability and reliability of the Stirling refrigerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A cross-sectional view of a push piston assembly for a Stirling refrigerator used in a low-temperature refrigerator.

[0021] Figure 2 yes Figure 1 A partial enlarged view of .

[0022] Figure 3 Another cross-sectional view of a push piston assembly for a Stirling refrigerator used in a low-temperature refrigerator (showing the air inlet hole).

[0023] Figure 4 yes Figure 3 A partial enlarged view of .

[0024] Figure 5 It is another cross-sectional view of a push piston assembly for a Stirling refrigerator used in a low-temperature refrigerator (showing the air outlet holes, which are not limited to a row of four holes and can be freely selected according to the size and length of the piston).

[0025] Figure 6 yes Figure 5 Magnified view of the circled area.

[0026] Among them, 1 is the guide piston rod, 2 is the guide piston, 3 is the valve plate seat, 4 is the valve plate, 5 is the push air flotation liner, 6 is the porous medium component, 7 is the push piston, 8. the first micro-annular groove, 9. the second micro-annular groove, 10. the expanded slot hole. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0028] The present invention designs a push piston assembly of a Stirling refrigerator, which uses only a metal porous medium to control the inlet and outlet air flow rates. After the airflow enters the microgroove, it is evenly distributed and throttled by small holes on the surface of the piston. Compared with the throttle throttling, the air outlet is more uniform, the flow consistency is good, the control cost is low, the assembly yield is high, and the assembly time is short; the push piston is filled with soft cotton, and the total mass of the piston assembly can be flexibly adjusted, and the heat exchange between the guide piston and the push piston is isolated. Compared with the support liner, the isolation is better and the cost is lower. At the same time, the difficulty of assembling the coaxiality of the push piston and the guide piston is further reduced, thereby improving the assembly yield of the component and stabilizing the performance consistency of the refrigerator.

[0029] See also Figure 1-6 A push piston assembly for a Stirling refrigerator for a low-temperature refrigerator includes a guide piston rod 1, a guide piston 2, a valve plate seat 3, a valve plate 4, a push air flotation inner sleeve 5, a porous medium component 6, and a push piston 7.

[0030] See also Figure 1-4 A coaxial hole is machined at the center of the upper surface of the guide piston 2. The guide piston rod 1 is coaxially assembled with the guide piston 2 through the small hole. The two are connected by screws. The screws on the inner wall of the guide piston 2 are fixed with nuts, and the contact between the nut and the guide piston 2 is sealed with glue to prevent leakage of high-pressure gas inside the guide piston 2;

[0031] See also Figure 1-2The valve plate component includes a valve plate seat 3 and a valve plate 4. The valve plate component is connected to the guide piston 2 by screws. There is a through hole on the upper surface of the guide piston 2. The gas flows in from the hole and passes through the valve plate seat 3 to open the valve plate 4 and enter the internal cavity of the guide piston 2. Then the high-pressure gas flows into the porous medium component 6 for primary throttling. The valve plate component has the function of a one-way valve;

[0032] See also Figure 4 , push the upper and lower grooves of the air flotation inner sleeve 5 to place O-rings for sealing. There are two microgrooves in the middle, and there is a gap between the microgrooves. The gas that has been throttled once by the porous medium component 6 flows into the large microgroove (the first micro-annular groove 8) through the small holes to rectify the uniform airflow. The gas in this microgroove flows into the small microgroove (the second micro-annular groove 9) through the gap and enters the small holes on the surface of the guide piston for secondary throttling. The small microgroove and the small holes on the surface of the guide piston 2 overlap by half (it can also be a one-third or two-thirds ratio, etc.), the purpose is to control the gas output. The number of small holes and the number of rows can be freely selected according to the size and length of the piston, and are not limited to four small holes in a row. Figure 1-6 The porous medium component 6 can be made of metal or non-metal.

[0033] See also Figure 2 The push-pull air flotation inner sleeve 5 is connected to the guide piston assembly with screws and fastened with nuts. The contact points between the upper and lower surfaces of the push-pull air flotation inner sleeve 5 and the nuts are sealed with glue to prevent air leakage.

[0034] In this embodiment, the push piston 7 is filled with silk floss, weighed and the total weight of the push piston assembly is controlled within the error range of 0.1g, and then the push piston 7 is glued to the guide piston assembly. The main function of the silk floss is to balance the weight and isolate the heat exchange between the guide piston and the push piston. The attached figure does not directly show the silk floss.

[0035] A method for assembling a push piston assembly for a Stirling refrigerator for a low-temperature refrigerator, comprising the following steps:

[0036] Step 1: First, connect the coaxial holes on the upper surface of the guide piston rod 1 and the guide piston 2 with screws to ensure that the coaxiality of the two is within 0.01mm, tighten them with nuts, and apply glue to the contact point between the nut and the guide piston 2 to prevent air leakage.

[0037] Step 2: Connect the valve seat 3 and valve plate 4 in the valve plate component to the guide piston 2 through screws. The valve plate component is close to the inner hole surface of the guide piston 2. When the gas enters through the small hole on the upper surface of the guide piston 2, the valve plate 4 is opened. The valve plate component acts as a one-way valve, so that the external high pressure can still be maintained when the piston resets backward, thereby achieving the effect of flotation.

[0038] Step 3: Place the porous medium component 6 into the small hole of the push-pull air flotation liner 5 .

[0039] Step 4: Connect the push air flotation inner sleeve 5 and the guide piston component with screws, tighten them with nuts, and apply glue to the contact area between the nut and the push air flotation inner sleeve 5 to prevent air leakage; use O-rings to seal the upper and lower grooves where the push air flotation inner sleeve 5 contacts the guide piston to ensure that the gas can only enter the micro-groove of the push air flotation inner sleeve 5 and flow into the small hole of the guide piston for secondary throttling through the small hole after one throttling through the porous medium component 6.

[0040] Step 5: Step 5 should be to use a tool to inspect the air of the assembled guide piston assembly, adjust the air flow by controlling the pressure regulating valve, and judge the quality of the air bearing assembly of the guide piston assembly by reading the flow meter;

[0041] Step 6: Place the silk floss into the push piston 7, weigh it and ensure that the total weight control accuracy of the push piston assembly is 0.1g, and then glue the push piston 7 and the guide piston together.

[0042] In summary, compared with the prior art, the present invention simplifies the structure and reduces the cost: by improving the throttle design in the push piston assembly, the traditional complex throttle structure is eliminated, and the metal porous medium and micro grooves are used for air flow throttling. Compared with the traditional throttle throttling method, this design not only reduces the complexity of the piston structure, but also effectively reduces the manufacturing cost, while reducing the weight of the piston assembly, making the movement of the piston in the low-temperature refrigerator Stirling refrigerator more stable, which helps to improve the overall refrigeration efficiency. Although the traditional support lining (background technology citation) can provide a certain thermal insulation effect, due to the limited thermal insulation effect and increased structural complexity and mass, the use of silk cotton to fill the push piston can reduce the mass of the piston and the thermal insulation effect of the push piston and the guide piston will be better than the support lining; improve the thermal insulation effect and weight control: the present invention fills the push piston with a flexible material (silk cotton), which not only has good thermal insulation performance, but also significantly reduces the weight of the piston. Compared with the traditional support lining, the silk cotton material is lighter, and due to its uniform structure and good thermal insulation ability, it effectively blocks the heat exchange between the push piston and the guide piston, and improves the refrigeration effect of the system. At the same time, the use of silk cotton also simplifies the piston structure, so that the overall weight of the piston assembly is controlled within the range of ±0.1g, achieving precise quality control. Through precise weight adjustment, the piston maintains dynamic balance during operation, thereby reducing unnecessary energy loss and improving the operating stability and reliability of the Stirling refrigerator.

[0043] The above are preferred embodiments of the present invention. Ordinary technicians in this field can also make various changes or improvements on this basis. Without departing from the overall concept of the present invention, these changes or improvements should fall within the scope of the protection required by the present invention.

Claims

1. A push piston assembly for a Stirling refrigerator, comprising a guide piston rod (1), a guide piston (2), and a push piston (7), characterized in that: It also includes a push air-floating inner sleeve (5), wherein the push air-floating inner sleeve (5) is fixed to the inner side of the guide piston (2) and has a first gap with the guide piston (2); A valve plate component is provided at a position on the inner side of the guide piston (2) corresponding to the air suction hole; A porous medium component (6) is provided on the push air flotation inner sleeve (5) directly opposite to the first gap, and the porous medium component is connected to a first micro-annular groove (8) located around the guide piston (2) through a first small hole on the push air flotation inner sleeve (5); a second micro-annular groove (9) is provided around the guide piston (2) beside the first micro-annular groove, and a set second gap is provided between the area between the first micro-annular groove (8) and the second micro-annular groove (9) and the guide piston (2), and the first micro-annular groove (8) and the second micro-annular groove (9) are connected through the second gap; and by analogy, the Nth micro-annular groove and the N+1th micro-annular groove are connected through the N+1th gap, N≥1; A second small hole is provided on the guide piston (2) at the location of the N+1th micro-annular groove and partially overlaps with the N+1th micro-annular groove, and the second small hole is communicated with the outside of the side wall of the guide piston (2).

2. The push piston assembly for a Stirling refrigerator according to claim 1, characterized in that: The push piston (7) is fixed to the guide piston (2) to form an internal space, in which a flexible material is placed. The flexible material is used to adjust the counterweight of the push piston assembly for the Stirling refrigerator and to isolate the heat exchange between the guide piston and the push piston.

3. The push piston assembly for a Stirling refrigerator according to claim 2, characterized in that: The flexible material is silk cotton, which is weighed to ensure that the total weight of the push piston assembly is controlled within an error range of 0.1 g, and then the push piston (7) is bonded to the guide piston assembly with glue.

4. The push piston assembly for a Stirling refrigerator according to claim 1, characterized in that: The volume of the first micro-annular groove (8) is larger than that of the second micro-annular groove (9).

5. The push piston assembly for a Stirling refrigerator according to claim 1, characterized in that: The porous medium component (6) is made of metal.

6. The push piston assembly for a Stirling refrigerator according to claim 1, characterized in that: The end of the second small hole is provided with an enlarged hole; the second small holes are arranged along the circumference of the guide piston (2), and the number and number of rows of the second small holes are adjusted according to the length of the guide piston (2).

7. The push piston assembly for a Stirling refrigerator according to claim 1, characterized in that: The push air-floating inner sleeve (5) is coaxially fixedly connected to the guide piston rod (1) via a short shaft, and the short shaft passes through the guide piston (2) and is fixed to the guide piston (2) via a nut.

8. The push piston assembly for a Stirling refrigerator according to claim 1, characterized in that: A coaxial hole is machined at the center of the surface of the guide piston (2). The guide piston rod (1) is coaxially assembled with the guide piston (2) through the coaxial hole. The two are connected by screws. The screws on the inner wall of the guide piston (2) are fixed with nuts, and the contact between the nut and the guide piston (2) is sealed with glue to prevent leakage of high-pressure gas inside the guide piston (2).

9. The push piston assembly for a Stirling refrigerator according to claim 1, characterized in that: The valve plate component comprises a valve plate seat (3) and a valve plate (4); the valve plate seat (3) is connected to the guide piston (2) via screws; and the valve plate component has the function of a one-way valve.

10. The push piston assembly for a Stirling refrigerator according to claim 1, characterized in that: O-rings are placed in the upper and lower grooves of the push air flotation inner sleeve (5) for sealing; the push air flotation inner sleeve (5) is connected to the guide piston assembly with screws and fastened with nuts, and the contact points between the upper and lower surfaces of the push air flotation inner sleeve (5) and the nuts are sealed with glue to prevent air leakage.

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