Plate spring and Stirling refrigerator
By designing unequal-thickness leaf springs, the radial stiffness and stress distribution uniformity of the Stirling refrigerator were improved, solving the problem of insufficient radial stiffness of leaf springs in the prior art, extending the service life of the piston assembly, and achieving lightweighting of the refrigerator.
Patent Information
- Application Number
- CN202422833238.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-11-20
AI Technical Summary
In existing small Stirling refrigerators, the radial stiffness of the flexible leaf springs is insufficient, which leads to piston wear, affects the service life of the refrigerator, and prevents its size from being reduced.
Design a leaf spring comprising a base circle and several cantilever arms, the cantilever arms extending in the same direction centered on the base circle, and optimizing the thickness distribution through an unequal thickness structure to improve radial stiffness and uniform stress distribution.
Without increasing the axial stiffness ratio, the radial stiffness is significantly improved, stress concentration is reduced, the service life of the piston assembly is extended, and the refrigerator is made lighter and smaller.
Smart Images
Figure CN223511388U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of Stirling refrigerators, and more particularly to a leaf spring and a Stirling refrigerator. Background Technology
[0002] In the structure of a small Stirling refrigerator, flexible leaf springs are typically used to support the piston to ensure that the piston can move without contact with the guide cylinder wall.
[0003] For example Figure 1 This illustrates the expander pushing assembly of a Stirling refrigerator in the prior art, which mainly includes: a piston assembly 1, a leaf spring 2, a guide cylinder 4, and a Dewar assembly 5. The leaf spring 2 is connected to the guide cylinder 4 and is axially fixed by a leaf spring fixing screw 3. At the same time, the leaf spring 2 is also connected to the piston assembly 1, and the guide cylinder 4 is connected to the Dewar assembly 5 by a cylinder positioning screw 6.
[0004] At the same time, such as Figure 3-4 As shown, the leaf spring 2 is a complete circular structure with consistent thickness in all parts, which leads to a significant increase in the radial dimension of the expander. Consequently, the overall size of the refrigeration unit exceeds the design requirements, making it difficult to achieve the goals of lightweighting and miniaturization.
[0005] Furthermore, when the overall dimensions, axial stiffness, and maximum displacement of the refrigerant are limited, the aforementioned equal-thickness plate spring 2 may exhibit insufficient radial stiffness or excessive maximum stress, failing to achieve sufficient radial support and design safety factor. This leads to wear of the push assembly (i.e., piston assembly), thereby affecting the working life of the expander. Utility Model Content
[0006] The purpose of this invention is to provide a leaf spring and a Stirling refrigerator. The leaf spring is lightweight and small in size. It can effectively improve the radial stiffness while maintaining a relatively constant ratio between maximum stress and axial stiffness. It also makes the stress distribution of the leaf spring more uniform during operation and effectively reduces stress concentration.
[0007] To achieve the above objectives, this utility model provides the following technical solution:
[0008] On the one hand, a leaf spring is provided, which includes:
[0009] The base circle portion has a base circle portion mounting hole;
[0010] And several cantilever arms, with one end of each cantilever arm connected to the base circle portion, and the other end of each cantilever arm extending freely in the same direction and around the vertical central axis of the base circle portion.
[0011] Preferably, at least one end of the cantilever that extends freely has a cantilever mounting hole.
[0012] Preferably, all cantilever sections are integrally formed with the base circle.
[0013] Preferably, all cantilever connections to one end of the base circle are evenly spaced in the circumferential direction.
[0014] Preferably, the distance between two adjacent cantilever arms is the same in the radial direction.
[0015] Preferably, the leaf spring has an unequal thickness structure.
[0016] Preferably, the thickness of the portion of the leaf spring with the base circle center as the center and the radius ≤ the first radius threshold R1 is the same, and the thickness of the portion with the first radius threshold R1 < radius ≤ the second radius threshold R2 gradually decreases from the inside to the outside in the radial direction.
[0017] Preferably, the thickness of the portion within the radius ≤ the first radius threshold R1 ranges from 0.3 to 0.5 mm.
[0018] Preferably, the minimum thickness of the portion within the range of the first radius threshold R1 < radius ≤ second radius threshold R2 is in the range of [0.1-0.3 mm].
[0019] On the other hand, a Stirling refrigerator is also provided, which includes the aforementioned leaf spring.
[0020] In summary, this utility model has the following advantages compared with the prior art:
[0021] The leaf spring of this invention is lightweight and compact. It can effectively improve radial stiffness while maintaining a relatively constant ratio between maximum stress and axial stiffness. It also makes the stress distribution of the leaf spring more uniform during operation, effectively reducing stress concentration. At the same time, it can adjust the coaxiality of the piston assembly, which can significantly reduce piston wear and extend the service life of the refrigeration unit. Attached Figure Description
[0022] Figure 1 This is a partial structural diagram of the expander pushing assembly of a Stirling refrigerator in the prior art.
[0023] Figure 2 This is a partial cross-sectional view of the expander pushing assembly of a Stirling refrigerator in the prior art.
[0024] Figure 3 This is a structural diagram of a leaf spring in the prior art.
[0025] Figure 4 This is a cross-sectional view of a leaf spring in the prior art.
[0026] Figure 5 This is an overall structural diagram of the leaf spring of this utility model.
[0027] Figure 6 This is a cross-sectional view of the leaf spring of this utility model.
[0028] Figure 7 The simulation results of the axial stiffness of the leaf spring in this utility model are based on existing technology.
[0029] Figure 8 The simulation results of the radial stiffness of the leaf spring in this utility model are based on existing technology.
[0030] Figure 9 The results are simulation experiments of the maximum stress of the leaf spring in the present invention, based on existing technology.
[0031] Figure 10 The test results are for the axial stiffness ratio K of the medium diameter in the prior art and this utility model.
[0032] Figure 11 The test results are for the maximum stress to axial stiffness ratio S in the prior art and in this utility model.
[0033] Figure 12 This is a partial structural diagram of the Stirling refrigeration unit in this utility model.
[0034] Figure 13 This is a partial cross-sectional view of the Stirling refrigeration unit in this utility model. Detailed Implementation
[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.
[0036] Example 1
[0037] like Figure 5-6 As shown, this embodiment provides a leaf spring S0, which includes:
[0038] The base circle portion 10 has a base circle portion mounting hole 101;
[0039] A plurality of cantilever arms 20, wherein one end of each cantilever arm 20 is connected to the base circle portion 10, and the other end extends freely in the same direction (such as counterclockwise or clockwise) and around the vertical central axis Y of the base circle portion 10; at the same time, each cantilever arm 20 is an arc-shaped structure, and at least one cantilever arm 20 has a cantilever mounting hole 201 on one freely extending end;
[0040] Preferably, in this embodiment, the number of cantilever 20 is greater than or equal to 3, and all cantilever 20 is integrally formed with the base circle portion 10, and the ends of all cantilever 20 connected to the base circle portion 10 are evenly spaced in the circumferential direction, and in the radial direction, the distance between two adjacent cantilever 20 is the same.
[0041] from Figure 2 As can be seen from Figure 5, compared with the leaf spring 2 in the prior art, in the leaf spring S0 of this embodiment, there is no extra support structure between the free ends of two adjacent cantilever 20 (i.e. the end with the cantilever mounting hole 201). Therefore, under the premise that the overall diameter of the leaf spring remains unchanged, its weight can be reduced from 0.356g to 0.184g, that is, the weight can be reduced by about 48.3%.
[0042] Furthermore, this embodiment conducts simulation experiments on the leaf spring 2 in the prior art and the leaf spring S0 in this embodiment, and the results are as follows. Figure 7-9 As shown in Table 1, it can be seen that, compared with the leaf spring 2 in the prior art, the leaf spring S0 in this embodiment has no significant changes in the three performance indicators of axial stiffness, radial stiffness, and maximum stress, indicating that its performance is consistent with that of the leaf spring 2 in the prior art. Therefore, it can replace the leaf spring 2 in the prior art while reducing weight and volume and maintaining the same performance.
[0043] Table 1. Simulation results of leaf spring performance.
[0044] Existing technology leaf springs This embodiment features a leaf spring. Axial stiffness N / mm 0.989 0.989 Radial stiffness N / mm 21.11 21.10 Maximum stress (MPa) (1.5mm displacement) 506.69 506.83
[0045] Example 2:
[0046] The only difference between this embodiment and Embodiment 1 is that, Figure 6As shown, the leaf spring S0 has an unequal thickness structure. With the center of the base circle 101 as the center, the thickness of the portion m within the radius ≤ the first radius threshold R1 is the same, which is a uniform thickness D1, and the value range of the uniform thickness D1 is [0.3-0.5mm]. The thickness of the portion n within the radius ≤ the first radius threshold R1 < the second radius threshold R2 gradually decreases from the inside to the outside in the radial direction. Its maximum thickness D2 < the uniform thickness D1, and the value range of the minimum thickness D3 is [0.1-0.3mm]. The first radius threshold R1 and the second radius threshold R2 can be predetermined according to the actual leaf spring size and the force conditions.
[0047] Furthermore, this embodiment conducts simulation experiments on the leaf spring 2 in the prior art and the leaf spring S0 in this embodiment, and the results are as follows. Figure 10-11 And as shown in Table 2.
[0048] Table 2. Leaf Spring Thickness Design
[0049] Uniform thickness D1 (mm) Minimum thickness D3 (mm) Leaf Spring Model 1 0.5 0.1 Leaf Spring Model 2 0.4 0.3 Leaf Spring Model 3 0.3 0.3 Leaf Spring Model 4 0.4 0.2 Leaf Spring Model 5 0.3 0.1
[0050] In this embodiment, leaf spring model 3 is equivalent to leaf spring 2 in the prior art, while leaf spring models 1, 2, 4, and 5 are all unequal-thickness leaf springs. Theoretically, leaf spring design requires a larger radial-axial stiffness ratio K while minimizing the ratio of maximum stress to axial stiffness S. Figure 10-11 As shown, compared to the leaf spring 3 in the prior art, the radial-axial stiffness ratio K of the leaf springs corresponding to leaf spring models 1, 2, 4, and 5 is greater than that of leaf spring 2. At the same time, the maximum stress and axial stiffness ratio S of the leaf springs corresponding to leaf spring models 2, 4, and 5 are not significantly different from those of leaf spring 2. In particular, the maximum stress and axial stiffness ratio S of leaf spring model 2 is smaller than that of leaf spring 2. This indicates that the leaf spring in this embodiment helps to improve the radial stiffness, thereby making the radial support capacity of piston assembly 1 stronger, making the stress distribution of the leaf spring more uniform during operation, effectively reducing stress concentration, and adjusting the coaxiality of piston assembly 1, which can significantly reduce piston wear and improve the service life of the refrigeration machine.
[0051] Example 3:
[0052] This embodiment provides a Stirling refrigerator, such as Figure 12-13 As shown, it includes: piston assembly 1, leaf spring S0 in embodiment 1 or 2, guide cylinder 4, and Dewar assembly 5;
[0053] The leaf spring S0 is connected to the guide cylinder 4. Fasteners such as the leaf spring fixing screw 3 pass through the mounting hole 101 of the base circle of the leaf spring S0. The leaf spring S0 is connected to the guide cylinder 4 to achieve axial fixation of the leaf spring S0. At the same time, the leaf spring S0 is also connected to the piston assembly 1. The guide cylinder 4 is connected to the Dewar assembly 5 through the cylinder positioning screw 6.
[0054] In summary, the leaf spring of this invention is lightweight and compact. It can effectively improve radial stiffness without significant changes in the ratio of maximum stress to axial stiffness S. This results in stronger radial support capacity of the piston assembly 1, more uniform stress distribution during operation of the leaf spring, effective reduction of stress concentration, and adjustment of the coaxiality of the piston assembly. This can significantly reduce piston wear and extend the service life of the refrigeration unit.
[0055] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A leaf spring, characterized in that, include: The base circle portion has a base circle portion mounting hole; And several cantilever arms, with one end of each cantilever arm connected to the base circle portion, and the other end of each cantilever arm extending freely in the same direction and around the vertical central axis of the base circle portion.
2. The leaf spring as described in claim 1, characterized in that, At least one end of the cantilever that extends freely has a cantilever mounting hole.
3. The leaf spring as described in claim 1, characterized in that, All cantilever arms are integrally molded with the base circle.
4. The leaf spring as described in claim 1, characterized in that, All cantilever connections to one end of the base circle are evenly spaced in the circumferential direction.
5. The leaf spring as described in claim 1, characterized in that, In the radial direction, the spacing between any two adjacent cantilever arms is the same.
6. The leaf spring as described in claim 1, characterized in that, The leaf spring has an unequal thickness structure.
7. The leaf spring as described in claim 6, characterized in that, The thickness of the leaf spring is the same for the portion with radius ≤ first radius threshold R1 centered on the base circle. The thickness of the portion with radius ≤ second radius threshold R2 gradually decreases radially from the inside to the outside.
8. The leaf spring as described in claim 7, characterized in that, The thickness of the portion within the radius ≤ the first radius threshold R1 ranges from 0.3 to 0.5 mm.
9. The leaf spring as described in claim 7, characterized in that, The minimum thickness of the portion within the range of the first radius threshold R1 < radius ≤ second radius threshold R2 is [0.1-0.3mm].
10. A Stirling refrigerator, characterized in that, Includes the leaf spring described in any one of claims 1-9.