A Stirling refrigerator

Abstract

This application discloses a Stirling refrigerator, comprising: a cylinder assembly, a power piston assembly, and a linear motor assembly. The power piston assembly includes a power piston and a power leaf spring, the cylinder assembly includes a power cylinder, and the linear motor assembly is configured to drive the power piston to perform linear reciprocating motion within the power cylinder. The power piston and power cylinder are provided with an anti-deviation structure and a pneumatic suspension structure. The pneumatic suspension structure includes an air float hole on the power piston; the anti-deviation structure includes a cylinder anti-deviation hole on the power cylinder, an annular anti-deviation groove on the power piston, a power piston anti-deviation hole, and an axial channel. By improving the internal structure, particularly the anti-deviation structure and the dynamic vibration damper structure, this refrigerator effectively prevents the power piston from generating deviation and current surges during operation, and improves the reliability and lifespan of the vibration damping structure.

Description

Technical Field

[0001] This application relates to the field of refrigeration technology, and in particular to a Stirling refrigerator. Background Technology

[0002] A Stirling refrigerator is a highly efficient refrigeration device based on the reverse Stirling cycle (or reverse Carnot cycle). Its core working principle is that a compressor drives a piston to make linear reciprocating motion in a cylinder, compressing and expanding the working gas (such as helium) to achieve a cooling effect.

[0003] In Stirling refrigerators, the key components of the compressor are the power piston assembly and the linear motor assembly. To ensure the power piston can operate efficiently and with low friction within the power cylinder for extended periods, a pneumatic suspension structure and an anti-deviation structure are typically designed between the power piston and the cylinder. The pneumatic suspension structure utilizes air flotation holes on the side of the power piston. High-pressure gas from the compression chamber forms an air film in the tiny gap between the piston and the cylinder, generating buoyancy and allowing the piston to suspend within the cylinder, thus achieving near-zero friction and zero wear.

[0004] However, simply having a pneumatic suspension structure still presents a critical problem. During compressor operation, the volume of the compression chamber is much smaller than that of the back pressure chamber. The reciprocating motion of the piston causes drastic pressure fluctuations in the compression chamber, with an amplitude much greater than that in the back pressure chamber. Simultaneously, some high-pressure gas inevitably leaks into the back pressure chamber through the tiny gap between the piston and cylinder, causing an increase in the average pressure of the back pressure chamber. This pressure imbalance (the difference between the average pressure and fluctuation amplitude in the compression chamber and the back pressure chamber) generates a net force at both ends of the power piston, causing the entire power piston to be biased towards the compression chamber. This bias reduces the effective stroke of the power piston, lowers the effective gas compression work, thereby weakening the cooling performance at the expansion end, and may even lead to cylinder knocking due to the piston approaching the cylinder end excessively, and trigger an abnormal surge in operating current.

[0005] Existing technologies typically integrate pneumatic suspension and anti-deviation structures onto the power piston and cylinder. The anti-deviation structure usually involves a limited number of fixed-position anti-deviation holes on both the cylinder and piston. This presents a design contradiction: increasing the size of the air flotation holes to enhance air flotation capacity, while providing better suspension, also leads to more high-pressure gas leakage into the back pressure chamber, exacerbating the pressure rise in the back pressure chamber. With a fixed anti-deviation structure (specifically, the diameter, position, and number of anti-deviation holes), its flow capacity and pressure regulation capability are fixed, failing to effectively cope with the increased back pressure rise caused by increased air flotation flow. This results in difficulty in effectively suppressing piston deviation, causing the power piston to still deviate, sudden changes in refrigerator current, increased risk of cylinder knocking, and reduced refrigeration performance. Conversely, reducing the air flotation hole flow rate can reduce leakage and alleviate deviation pressure, but the air flotation capacity will be insufficient to effectively maintain the piston's suspension state, leading to piston-cylinder wall contact friction and severely impacting the refrigerator's lifespan. More importantly, in the traditional anti-deviation hole design, the cylinder anti-deviation hole and the power piston anti-deviation hole will periodically misalign during the piston reciprocating motion, resulting in a discontinuous pressure balance channel. This limits the effect of dynamic pressure regulation and increases the requirements for hole position accuracy during assembly.

[0006] Furthermore, in Stirling refrigerators with a single-piston structure, the reciprocating motion of the piston generates significant axial vibration, which typically requires a dynamic vibration absorber to counteract it. The dynamic vibration absorber usually consists of a leaf spring support structure and a counterweight. When the refrigerator operates alone, its light weight allows the dynamic vibration absorber to meet vibration reduction requirements with only a small displacement. However, when the Stirling refrigerator is integrated into a final application (such as a refrigerator), the rigid connection to the refrigerator casing significantly increases the effective mass of the stator, forcing the dynamic vibration absorber to require a larger displacement to counteract the same magnitude of vibration. Traditional dynamic vibration absorbers typically use a method of directly stacking leaf springs, with a large counterweight placed on one side of the leaf spring structure. This structure has the following disadvantages: First, during stacking, the multiple leaf springs experience fretting wear at the contact surface due to differences in surface flatness and roughness. Especially with increased amplitude, this drastically reduces the fatigue strength of the leaf springs, making them prone to breakage. Second, suspending a large counterweight on one side generates a large bending moment on the leaf spring structure, resulting in low reliability over long-term operation.

[0007] Therefore, there is an urgent need in the field to develop a Stirling refrigerator to solve the above-mentioned technical problems, especially to optimize the anti-bias structure to prevent the power piston from generating bias and current surge during operation, and to improve the structure of the power vibration absorber to improve its vibration reduction reliability and fatigue life. Summary of the Invention

[0008] The purpose of this application is to provide a Stirling refrigerator that, through improvements to its internal structure, particularly the anti-deviation structure and the dynamic vibration damper structure, can effectively prevent the dynamic piston from generating deviation and current surge during operation, and improve the reliability and lifespan of the vibration damping structure.

[0009] This application provides a Stirling refrigerator, including: a cylinder assembly, a power piston assembly, and a linear motor assembly. The power piston assembly includes a power piston and a power leaf spring. The cylinder assembly includes a power cylinder. The linear motor assembly is configured to drive the power piston to perform linear reciprocating motion within the power cylinder.

[0010] Among them, the power piston and the power cylinder are provided with an anti-deviation structure and a pneumatic suspension structure, and the pneumatic suspension structure includes an air float hole provided on the power piston.

[0011] The anti-deviation structure includes a cylinder anti-deviation hole provided on the power cylinder, an annular anti-deviation groove provided on the power piston, a power piston anti-deviation hole, and an axial channel. The annular anti-deviation groove is a continuous groove machined around the entire circumference of the power piston, located between two rows of air float holes, and when the power piston is installed in the power cylinder, the annular anti-deviation groove and the cylinder anti-deviation hole are aligned in the axial direction.

[0012] The anti-deviation hole of the power piston is disposed on the annular anti-deviation groove. The axial channel is in fluid communication with the anti-deviation hole of the power piston. The axial channel extends from the anti-deviation hole of the power piston along the axial direction of the power piston and leads to the Stirling compression chamber. Thus, the gas in the Stirling compression chamber flows from the axial channel, through the annular anti-deviation groove and the cylinder anti-deviation hole to the back pressure chamber. The cylinder anti-deviation hole, the annular anti-deviation groove, the power piston anti-deviation hole and the axial channel form a microchannel to balance the gas pressure of the compression chamber and the back pressure chamber.

[0013] In another preferred embodiment, the number of anti-deviation holes of the power piston is at least 2.

[0014] Preferably, the number of anti-deviation holes in the power piston is 4.

[0015] In another preferred embodiment, the air float holes are arranged along the outer peripheral surface of the power piston, and the number of air float holes per air float hole is 4.

[0016] Preferably, the number of cylinder anti-deviation holes is at least 3. Preferably, the cylinder anti-deviation holes are through holes located on the side wall of the power cylinder, and the cylinder anti-deviation holes are opened along the circumferential wall surface of the cylinder.

[0017] In another preferred embodiment, the Stirling refrigerator further includes a dynamic vibration absorber structure and a housing assembly, wherein the dynamic vibration absorber structure, cylinder assembly, dynamic piston assembly, and linear motor assembly are all located within the housing assembly;

[0018] The dynamic vibration absorber structure includes a first dynamic vibration absorber counterweight, a second dynamic vibration absorber counterweight, and a damping plate spring structure. The damping plate spring structure includes a plurality of damping plate spring plates arranged at predetermined intervals. The first dynamic vibration absorber counterweight and the second dynamic vibration absorber counterweight are disposed on the upper and lower sides of the damping plate spring structure.

[0019] In another preferred embodiment, the distance between two adjacent damping leaf springs is 1 / 3 of the maximum stroke of a single damping leaf spring.

[0020] In another preferred embodiment, two adjacent damping leaf springs are separated by leaf spring spacers, the width of which is 1 / 3 of the limit stroke of a single damping leaf spring.

[0021] In another preferred embodiment, the weight of the first dynamic vibration absorber is equal to the weight of the second dynamic vibration absorber.

[0022] Preferably, the total mass of the first dynamic vibration absorber counterweight, the second dynamic vibration absorber counterweight, and the damping plate spring remains unchanged compared to the prior art structure with only one counterweight and damping plate spring. If only one counterweight is used, the diameter weight of the counterweight will increase in order to keep the weight constant (at the same time, a large counterweight on one side will increase the bending moment due to the shift in the center of gravity). If two counterweights are used, the diameter weight of a single counterweight can be reduced (the center of gravity is centered, and there is no bending moment).

[0023] In another preferred embodiment, the outer circumference of the plurality of damping leaf springs arranged at predetermined intervals is fixed to the housing of the housing assembly by screws and a damping stator, and the profiles of the plurality of damping leaf springs are arranged in a manner of cross-interference.

[0024] In another preferred embodiment, the outer circumference of the plurality of damping leaf springs arranged at predetermined intervals is fixed to the damping stator by screws, and then the damping stator is welded to the housing of the housing assembly.

[0025] Preferably, the profiles of multiple damping leaf springs are arranged in a manner of cross-interference, thereby increasing the wind resistance of the leaf spring movement, improving the bandwidth of the damping coverage, and making the damping effect more significant.

[0026] In another preferred embodiment, the linear motor comprises, from the inside to the outside, an inner magnetic yoke, a magnetic ring, and an outer magnetic yoke in its radial direction. The outer magnetic yoke has a recess facing the magnetic ring for winding a coil. A magnetic ring support frame is provided at the lower end of the magnetic ring and is connected to the power piston. When the energized coil interacts with the magnetic ring, the linear reciprocating motion of the magnetic ring drives the magnetic ring support frame to perform linear reciprocating motion, thereby driving the power piston to perform linear reciprocating motion within the power cylinder.

[0027] In another preferred embodiment, the coil is wound with flat wire, thereby increasing the number of turns of the coil within the limited space of the recess and improving motor efficiency. In another preferred embodiment, the power leaf spring is connected to the magnetic ring support frame via a first connector.

[0028] In another preferred embodiment, the power piston mechanism further includes a power leaf spring, which is connected to the magnetic ring support frame via a first connector.

[0029] In another preferred embodiment, the power leaf spring, the magnetic ring support frame, and the power piston are fixedly connected by the first connecting member.

[0030] In another preferred embodiment, the first connecting member is a power piston fixing screw, and the number of power piston fixing screws is 1, which is a ring-shaped screw.

[0031] In another preferred embodiment, the power piston is an annular component, the power piston includes a central cavity, and the Stirling refrigerator further includes a discharge piston assembly, the discharge piston assembly includes a first discharge piston and a discharge piston connecting rod, the discharge piston connecting rod passes sequentially through the power leaf spring, the magnetic ring support frame, the central cavity of the power piston and the compression chamber of the Stirling refrigerator in the axial direction of the discharge piston connecting rod, and is connected to the first discharge piston.

[0032] In another preferred embodiment, the magnetic ring support frame includes a first connecting portion and a second connecting portion. The first connecting portion is annular and substantially perpendicular to the second connecting portion. The first connecting portion is connected to the lower end of the magnetic ring, and the upper surface of the second connecting portion is connected to the lower surface of the power piston.

[0033] In another preferred embodiment, the discharge piston connecting rod passes through the second connecting portion and leaves a certain gap between it and the second connecting portion.

[0034] In another preferred embodiment, in the radial direction, a portion of the first connecting portion is located between the inner yoke and the outer yoke.

[0035] In another preferred embodiment, a cold finger assembly is further included, coaxially disposed on the upper end of the housing assembly. The cold finger assembly includes a cold finger base and a hot end heat sink, the hot end heat sink being located above the cold finger base, and the power cylinder being connected to the cold finger base.

[0036] A second aspect of this application provides a refrigerator comprising the Stirling refrigeration unit described above.

[0037] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. It should be understood that the accompanying drawings described below are merely some implementation examples of the present invention, and those skilled in the art can obtain other implementation examples based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram showing the positional relationship between the cylinder anti-deviation hole and the power piston anti-deviation hole of a Stirling refrigerator according to an embodiment of this application.

[0040] Figure 2 This is a schematic diagram of a portion of the anti-deviation structure of a Stirling refrigerator according to an embodiment of this application, showing the anti-deviation hole and annular anti-deviation groove on the power piston.

[0041] Figure 3 This is a schematic diagram of the structure of a power piston including an anti-deviation structure in a Stirling refrigerator according to an embodiment of this application;

[0042] Figure 4 This is a schematic diagram of the dynamic vibration absorber structure of a Stirling refrigerator according to an embodiment of this application;

[0043] Figure 5 This is an isometric schematic diagram of the dynamic vibration absorber structure of a Stirling refrigerator according to an embodiment of this application;

[0044] Figure 6 This is an interference diagram of the leaf spring profile of an axial dynamic vibration absorber structure according to an embodiment of this application;

[0045] Figure 7 This is a schematic diagram of the structure of a Stirling refrigerator according to an embodiment of this application.

[0046] Figure 8This is a schematic diagram of a magnet-embedded linear motor in a Stirling refrigerator according to one embodiment of this application.

[0047] In each of the attached figures, the markings are as follows:

[0048] 100 - Air float hole; 200 - Cylinder anti-deviation hole; 300 - Annular anti-deviation groove; 400 - Power piston anti-deviation hole; 500 - Axial channel;

[0049] 1-Cold cap; 2-Cold end heat exchanger; 3-Discharge cylinder; 4-Regenerator shell; 5-Second discharge piston; 6-Hot end copper chain; 7-Hot end radiator; 8-Cold finger base; 9-Shell;

[0050] 10-Coil; 11-Outer yoke; 12-Electrode; 13-Soft magnetic mounting bracket; 14-Electrode welding shell; 15-Vibration damping counterweight nut; 16-Vibration damping counterweight block; 17-Vibration damping leaf spring; 18-Vibration damping counterweight screw; 19-Vibration damping fixing screw; 20-Leaf spring locking screw; 21-Vibration damping fixing shaft; 22-Discharge leaf spring; 23-Leaf spring support column; 24-Power leaf spring; 25-Power piston fixing screw;

[0051] 26-Magnetic ring support frame; 261-First connecting part; 262-Second connecting part;

[0052] 27-Inner magnetic yoke fixing aluminum ring; 28-Inner magnetic yoke; 29-Magnetic ring; 30-Power piston; 31-Connecting rod; 32-Power cylinder; 33-First discharge piston; 34-Regenerator; 35-Cold end copper chain. Detailed Implementation

[0053] Through extensive and in-depth research, the inventors have developed a Stirling refrigerator for the first time. By improving the anti-deviation structure of the Stirling refrigerator, the compressor is guaranteed to operate without deviation or current surge throughout its entire stroke range. Furthermore, the anti-deviation hole of the power piston does not need to be aligned with the anti-deviation hole of the cylinder, simplifying the assembly process. In addition, by improving the structure of the power vibration absorber, the fretting wear of the damping plate spring sheet in the power vibration absorber structure is reduced, thereby improving fatigue strength and operational stability. Moreover, by setting up a magnet-embedded linear motor, the high-order frequency component of the motor current is significantly reduced, thereby reducing the high-order vibration and noise of the refrigerator and improving operational stability.

[0054] In the following description, many technical details are presented to help the reader better understand this application. However, those skilled in the art will understand that the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0055] the term

[0056] As used herein, the terms “axial” and “axial direction” are used interchangeably, as are the terms “radial” and “radial direction”.

[0057] As used herein, the terms “linear motor assembly” and “linear motor” are used interchangeably;

[0058] As used herein, the terms "integrated cylinder" and "power cylinder" are used interchangeably;

[0059] In this invention, all directional indicators (such as up, down, left, right, front, back, etc.) are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0060] This application has at least one of the following advantages:

[0061] (a) This application sets a continuous annular anti-deviation groove around the entire circumference between the two exhaust float holes of the power piston, and opens multiple power piston anti-deviation holes on the annular groove. This structure greatly enhances the gas return capacity from the back pressure chamber to the compression chamber. Even during the movement of the power piston, the cylinder anti-deviation hole always remains connected with the annular groove, ensuring the continuous effectiveness of the pressure balance channel. This effectively suppresses the deviation of the power piston throughout the entire stroke range, avoiding current surge and cylinder collision risk. At the same time, due to the existence of the annular groove, it is not necessary to precisely align the power piston anti-deviation hole and the cylinder anti-deviation hole during assembly, simplifying the assembly process.

[0062] (b) The dynamic vibration absorber structure of this application adopts a design with counterweights on both sides, placing the first and second dynamic vibration absorber counterweights on the upper and lower sides of the damping plate spring structure respectively, which balances the bending moment caused by the large mass body suspended on one side, thereby improving the stability of operation;

[0063] (c) The dynamic vibration absorber structure of this application arranges multiple damping leaf springs at certain intervals instead of stacking them directly. Preferably, they are isolated by a shim with a thickness / width of 1 / 3 of the limit stroke of the damping leaf spring. The shim does not interfere with the profile of the leaf spring, effectively reducing the contact area and fretting wear between the damping leaf springs, and significantly improving the fatigue strength and long-term operational reliability of the leaf spring.

[0064] (d) The dynamic vibration absorber structure of the Stirling refrigerator of this application, by arranging multiple individual damping plate springs at intervals, eliminates the need for precise matching of each damping plate spring compared to damping plate springs that are stacked together.

[0065] (e) The Stirling refrigerator of this application significantly reduces the high-order frequency component of the motor current by setting a linear motor with built-in magnet, thereby reducing the high-order vibration and noise of the refrigerator and improving the operational stability.

[0066] (f) The Stirling refrigerator of this application integrates the cylinder seat and the cylinder into one unit and is made of the same material. It not only undertakes the mechanical connection of the cylinder seat, but also undertakes the functions of sealing the cylinder gap and smooth wear resistance, which significantly reduces the processing cost and process flow and facilitates mass production.

[0067] To make the objectives, technical solutions, and advantages of the present invention clearer, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. It should be understood that these are merely examples provided to the reader of possible implementations of the present invention and are not intended to limit the scope of the invention.

[0068] A Stirling refrigerator

[0069] This application provides a Stirling refrigerator, see [link to details]. Figure 1-3 and Figure 7 The Stirling refrigerator includes a housing assembly, a cylinder assembly, a power piston assembly, a discharge piston assembly, a linear motor assembly, a power vibration damper structure, and a cooling finger assembly. The power piston assembly includes a power piston and a power leaf spring. The cylinder assembly includes a power cylinder. The linear motor assembly is configured to drive the power piston to perform linear reciprocating motion within the power cylinder.

[0070] Anti-deviation structure and aerodynamic suspension structure

[0071] refer to Figures 1 to 3 An anti-deviation structure and a pneumatic suspension structure are provided on the power piston and the power cylinder. The pneumatic suspension structure includes an air float hole 100 on the power piston. The anti-deviation structure is one of the core improvements of this application. The anti-deviation structure mainly includes at least two cylinder anti-deviation holes 200 on the power cylinder 32, and an annular anti-deviation groove 300, a power piston anti-deviation hole 400, and an axial channel 500 on the power piston 30.

[0072] The annular anti-deviation groove 300 is a continuous groove machined around the entire circumference of the power piston, located between the two exhaust float holes 100 on the outer circumference surface of the power piston. When the power piston 30 is installed in the power cylinder 32, the annular anti-deviation groove 300 and the cylinder anti-deviation hole 200 are aligned in the axial direction.

[0073] The anti-deviation hole 400 of the power piston is provided on the annular anti-deviation groove 300. The axial channel 500 is in fluid communication with the anti-deviation hole 400 of the power piston. The axial channel 500 extends from the anti-deviation hole 400 of the power piston along the axial direction of the power piston and leads to the Stirling compression chamber. Thus, the gas in the Stirling compression chamber flows from the axial channel 500, through the anti-deviation hole 400 of the power piston on the annular anti-deviation groove 300 and the anti-deviation hole 200 of the cylinder, to the back pressure chamber. The anti-deviation hole 200 of the cylinder, the annular anti-deviation groove 300, the anti-deviation hole 400 of the power piston and the axial channel 500 form a microchannel to balance the gas pressure of the compression chamber and the back pressure chamber.

[0074] During compressor operation, pressure fluctuations in the compression chamber can cause gas to flow to the back pressure chamber via the following path: compression chamber → axial channel 500 → power piston anti-deviation hole 400 → annular anti-deviation groove 300 → cylinder anti-deviation hole 200 → back pressure chamber. More importantly, when the pressure in the back pressure chamber is too high, the gas can also flow in the opposite direction via this path (back pressure chamber → cylinder anti-deviation hole 200 → annular anti-deviation groove 300 → power piston anti-deviation hole 400 → axial channel 500 → compression chamber), thereby achieving dynamic pressure balance between the two chambers.

[0075] Preferably, the number of anti-deviation holes 400 on the power piston is at least 2, and more preferably, the number of anti-deviation holes 400 on the power piston is 4.

[0076] Preferably, the number of cylinder anti-deviation holes 200 is at least 2.

[0077] Preferably, the air float holes 100 are arranged along the outer peripheral surface of the power piston, and the number of air float holes 100 per air float is 4.

[0078] In one embodiment, by machining a groove (i.e., annular anti-deviation groove 300) around the circumference of the anti-deviation hole 400 of the power piston and setting an axial channel 500 along the axial direction from the anti-deviation hole 400 of the power piston, and setting the number of anti-deviation holes 400 of the power piston to 4, this method enhances the gas flow rate of high-pressure gas returning from the back pressure chamber to the compression chamber, significantly suppresses the current surge problem caused by the deviation of the power piston, and has little impact on the coefficient of performance (COP) of the refrigerator.

[0079] Dynamic vibration absorber structure

[0080] like Figure 4-6 As shown, the dynamic vibration absorber structure of this application includes a first dynamic vibration absorber counterweight, a second dynamic vibration absorber counterweight, and a damping plate spring structure. The damping plate spring structure includes a plurality of damping plate spring plates 17 arranged at predetermined intervals. The first dynamic vibration absorber counterweight and the second dynamic vibration absorber counterweight are disposed on the upper and lower sides of the damping plate spring structure.

[0081] In one embodiment, both the first and second dynamic vibration absorber counterweights include a vibration damping counterweight nut 15, a vibration damping counterweight block 16, and a vibration damping counterweight screw 18. The first and second dynamic vibration absorber counterweights are fixedly connected by a vibration damping fixing shaft 21 and a vibration damping fixing screw 19. The vibration damping leaf spring 17 is fixedly connected to the housing 9 by a leaf spring locking screw 20.

[0082] Preferably, the distance between two adjacent damping plate springs 17 is 1 / 3 of the maximum stroke of a single damping plate spring 17.

[0083] Preferably, two adjacent damping leaf springs 17 are separated by leaf spring spacers, the width of which is 1 / 3 of the limit stroke of a single damping leaf spring.

[0084] Preferably, the outer circumference of the plurality of damping plate spring sheets arranged at predetermined intervals is fixed to the damping stator by screws, and then the stator is welded to the housing.

[0085] The profiles of multiple damping leaf springs are arranged according to a cross-interference pattern, thereby increasing the wind resistance of the leaf spring movement, expanding the frequency band of the damping coverage, and making the damping effect more significant. See [link to relevant documentation]. Figure 6 .

[0086] Dynamic vibration absorber structural design method

[0087] This application designs the structure of a dynamic vibration absorber using the following method: First, a model of a refrigeration unit's spring oscillator system is established. The refrigeration unit's outer casing is considered as the stator. The dynamic piston assembly and its dynamic spring, along with the discharge piston assembly and its discharge spring, constitute the first part of the spring oscillator system. The damping plate spring and the large mass body (i.e., the counterweight of the dynamic vibration absorber) in the dynamic vibration absorber constitute the second part of the spring oscillator system. By combining the inertial force and phase of the dynamic piston assembly with the inertial force and phase of the discharge piston assembly through simulation calculations, the combined force and frequency acting on the refrigeration unit's outer casing are obtained. Then, the spring stiffness and dynamic mass of the dynamic vibration absorber are calculated. Generally, the ratio of dynamic mass to stator mass in a dynamic vibration absorber must be above 0.05 to ensure a wider frequency range for vibration reduction and suppression. The dynamic mass of the dynamic vibration absorber is obtained using this method, and the stiffness is calculated using the natural frequency formula. Since the required stiffness is very high, multiple leaf springs are typically used. Different spring designs produce different multi-order vibration modes. In actual operation, the movement of the leaf springs is a comprehensive manifestation of these multi-order modes. The greater the stroke, the more severe the irregularity of the leaf spring movement, especially noticeable when placing a refrigerator on it. Stacking leaf springs can cause fretting wear and reduce lifespan. Adding thin shims between leaf springs can cause mutual interference and abnormal noise during operation. Based on this, and considering the stroke and vibration mode, it is proposed that the thickness / width of the shims between the leaf springs in the vibration absorber should be at least 1 / 3 of the limit stroke to ensure efficient, reliable, and long-life operation of the vibration absorber springs. Simultaneously, considering the bending moment effect of the large mass on the vibration absorber, the large mass is divided into two parts and placed at the beginning and end of the vibration absorber to balance the bending moment and improve the stability of the dynamic vibration absorber operation.

[0088] Linear motor assembly

[0089] like Figure 7 and 8 As shown, the linear motor assembly of the Stirling refrigerator in this application is a linear motor with an internal magnet and an external coil.

[0090] The linear motor assembly includes, from the inside to the outside, an inner magnetic yoke 28, a magnetic ring 29, and an outer magnetic yoke 11 along its radial direction. The outer magnetic yoke 11 has a recess facing the magnetic ring 29, which is used to wind the coil 10. A magnetic ring support frame 26 is provided at the lower end of the magnetic ring 29. The magnetic ring support frame 26 is connected to the power piston 30. When the energized coil 10 interacts with the magnetic ring 29, the linear reciprocating motion of the magnetic ring 29 drives the magnetic ring support frame 26 to perform linear reciprocating motion, thereby driving the power piston 30 to perform linear reciprocating motion in the power cylinder 32.

[0091] When energized, the alternating current flowing through coil 10 generates an alternating magnetic field. This magnetic field interacts with the magnetic ring 29, causing the magnetic ring 29 and its support frame 26 to reciprocate linearly along the axial direction. This reciprocating motion is then connected to the power piston 30 via the power piston fixing screw 25, driving the power piston 30 to reciprocate within the power cylinder 32, compressing the working gas. Simultaneously, the discharge piston, under the pressure wave of the compression chamber and the action of the discharge leaf spring, maintains a certain phase difference with the power piston, completing the Stirling cycle. Preferably, the coil is wound with flat wire, thereby increasing the number of turns within the limited space of the recess, improving motor efficiency.

[0092] Since the magnet (magnetic ring 29) is located inside the mover and the coil is fixed on the outer magnetic yoke 11, the high-order electromagnetic force components experienced by the magnetic ring 29 during the movement are significantly reduced, thereby effectively reducing the high-frequency vibration caused by motor excitation.

[0093] The lower end of the magnetic ring 29 is connected to a magnetic ring support frame 26, which is used to transmit the linear motion of the magnetic ring 29 to the piston assembly.

[0094] The magnetic ring support frame 26 includes a first connecting part 261 and a second connecting part 262. The first connecting part 261 is annular and is substantially perpendicular to the second connecting part 262. The first connecting part 261 is connected to the lower end of the magnetic ring 29, and the upper surface of the second connecting part 262 is connected to the lower surface of the power piston 30.

[0095] The coil 10 is wound inside the recess of the outer magnetic yoke 11, forming a winding connection with the outer magnetic yoke 11 to constitute the excitation coil structure of the linear motor.

[0096] Preferably, the magnetic ring support frame 26 and the magnetic ring 29 are fixedly connected by adhesive to ensure the structural stability of the magnetic ring during reciprocating motion.

[0097] The housing assembly also includes a motor fixing structure, which includes a soft magnetic fixing frame 13. The upper end face of the soft magnetic fixing frame 13 is connected to the outer magnetic yoke 11, and the lower end face of the soft magnetic fixing frame 13 is connected to the power leaf spring 24.

[0098] The outer magnetic yoke 11 is also located below the cold finger base 8. The soft magnetic fixing frame 13, the outer magnetic yoke 11 and the cold finger base 8 are connected by screw fixing, so that the motor magnetic circuit structure and the whole frame form an integrated support.

[0099] Preferably, in the radial direction, the soft magnetic fixing frame 13 is located outside the magnetic ring support frame 26.

[0100] Preferably, the motor fixing structure further includes an inner magnetic yoke fixing aluminum ring 27, which is located directly below the inner magnetic yoke 28.

[0101] The inner magnetic yoke 28, the inner magnetic yoke fixing aluminum ring 27, and the power cylinder 32 are fixedly connected by adhesive to ensure the stability of the magnetic circuit structure and reduce assembly gaps.

[0102] The magnetic ring support frame 26, the power piston fixing screw 25, and the power piston 30 are connected by threads, thereby reliably transmitting the linear motion of the magnetic ring to the power piston 30.

[0103] The applicant conducted simulation calculations on the linear motor with built-in magnets and external coils in this application, and found that this configuration of built-in magnets and external coils significantly reduces the high-order frequency components of the motor current, thereby reducing the high-order vibration and noise of the refrigerator and improving the operational stability.

[0104] Cylinder assembly and piston assembly

[0105] The cylinder assembly and piston assembly are the core components for achieving gas compression and expansion. The piston assembly includes the power piston assembly and the exhaust piston assembly.

[0106] The cylinder assembly is housed inside the housing assembly and consists of a power cylinder 32 (i.e., an integrated cylinder) and an exhaust cylinder 3. The exhaust cylinder 3 is made of plastic, while the power cylinder 32 is made of metal (such as aluminum alloy, titanium alloy, stainless steel, etc.).

[0107] The discharge cylinder 3 is connected to the upper outer side of the power cylinder 32 via a threaded connection, facilitating assembly and maintenance. The power cylinder 32 is machined with an annular groove for the flow of gas in the compression chamber.

[0108] The power cylinder 32 includes a first cylinder section, a second cylinder section, and a third cylinder section. In the radial direction, the first cylinder section is located between the power piston 30 and the inner magnetic yoke 28, and the second cylinder section is connected to the cold finger base 8. The first discharge piston 33 reciprocates within the third cylinder section.

[0109] The power piston assembly includes a power piston 30 and a power leaf spring 24. The power piston 30 is an annular component with a central cavity. It is connected to the magnetic ring support frame 26 via a power piston fixing screw 25, the power leaf spring 24, and the second connecting part 262 of the magnetic ring support frame 26. In the axial direction, the power leaf spring 24 is located below the magnetic ring support frame 26. Preferably, there is one power piston fixing screw, and the power piston screw 25 is annular. The long side of the power piston screw 25 passes through the second connecting part 262 of the magnetic ring support frame 26 and the power piston 30 in sequence. The head of the power piston screw 25 is located below the power leaf spring 24, and the discharge piston connecting rod 31 also passes through the power piston screw 25.

[0110] The discharge piston assembly includes a first discharge piston 33, a second discharge piston 5, a discharge piston connecting rod 31, and a discharge leaf spring. In the axial direction of the discharge piston connecting rod 31, the discharge piston connecting rod 31 passes sequentially through the power leaf spring 24, the magnetic ring support frame 26 (the first connecting part 261 of the magnetic ring support frame 26), the central cavity of the power piston 30, and the compression chamber of the Trin refrigerator, and is connected to the first discharge piston 33.

[0111] The discharge leaf spring 22 is located at the end of the discharge leaf spring 22 opposite to the first discharge piston 33.

[0112] The discharge leaf spring 22 is fixed to the soft magnetic bracket 13 by screws and leaf spring support column 23. Its central area is connected to the end of the discharge piston connecting rod 31, providing radial support and axial elastic restoring force for the discharge piston.

[0113] The power leaf spring 24 and the discharge leaf spring 22 are pressed together by screws and leaf spring support column 23. The leaf spring support column 23 is connected to the soft magnetic fixing frame 13 by threads.

[0114] The second discharge piston 5 is threadedly connected to the first discharge piston 33. The second discharge piston 5 reciprocates within the discharge cylinder 3 under the drive of the discharge piston connecting rod 31.

[0115] Preferably, the second discharge piston is made of plastic, and the first discharge piston is made of metal.

[0116] housing assembly

[0117] The housing assembly includes a housing 9, which is a cylindrical structure with an open top and a closed bottom. The housing 9 covers the outer side of the outer magnetic yoke 11 in the radial direction, and its upper end is connected to the cold finger base 8.

[0118] An electrical interface is provided on the side of the housing 9 for the electrode 12 to pass through, enabling the connection between the external power supply and the internal coil 10. The housing 9, the electrode 12, and the electrode welding shell 14 are connected by welding, thereby achieving reliable lead-out of the electrical interface and structural sealing.

[0119] Cold finger components

[0120] The cooling component is used to achieve the cooling effect and is located at the top of the unit.

[0121] The cold finger assembly includes a cold cap 1, a cold end heat exchanger 2, a cold end copper chain 35, a regenerator 34, a hot end copper chain 6, a hot end radiator 7, and a cold finger base 8 arranged sequentially from top to bottom along the axial direction.

[0122] The regenerator 34 is encased in a regenerator shell 4. The cold-end heat exchanger 2 is fitted over the cold-end copper chain 35 and the regenerator shell 4, and is used to efficiently transfer cooling energy to the cold cap 1. The hot-end radiator 7 is welded and fixed to the cold finger base 8. This structure achieves efficient heat exchange of the working fluid between the hot and cold ends in the Stirling cycle. Specifically, cooling energy is conducted away from the cold head (i.e., the cold-end heat exchanger 2 and the cold cap 1), while heat is conducted through the hot-end copper chain 6 to the hot-end radiator 7 and dissipated into the environment.

[0123] The cold cap 1, cold end heat exchanger 2, regenerator shell 4, hot end radiator 7, and cold finger base 8 are fixedly connected by welding to form a stable and reliable overall structure of the cold finger assembly. The hot end copper chain 6, regenerator 34, and cold end copper chain 35 are arranged sequentially along the axial direction and are connected by compression to ensure good thermal contact.

[0124] It should be noted that in this patent application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this patent application, if it refers to performing an action according to an element, it means performing the action at least according to that element, including two cases: performing the action only according to that element, and performing the action according to that element and other elements. Expressions such as "multiple," "repeatedly," and "various" include two, two times, two kinds, and more than two, more than two times, and more than two kinds.

[0125] All documents mentioned in this application are considered to be incorporated in their entirety into the disclosure of this application so that they can serve as a basis for modifications if necessary. Furthermore, it should be understood that after reading the foregoing disclosure of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A Stirling refrigerator, characterized in that, include: The cylinder assembly, the power piston assembly, and the linear motor assembly, wherein the power piston assembly includes a power piston and a power leaf spring, the cylinder assembly includes a power cylinder, and the linear motor assembly is configured to drive the power piston to perform linear reciprocating motion within the power cylinder. Among them, the power piston and the power cylinder are provided with an anti-deviation structure and a pneumatic suspension structure, and the pneumatic suspension structure includes an air float hole provided on the power piston. The anti-deviation structure includes a cylinder anti-deviation hole provided on the power cylinder, an annular anti-deviation groove provided on the power piston, a power piston anti-deviation hole, and an axial channel. The annular anti-deviation groove is a continuous groove machined around the entire circumference of the power piston, located between two rows of air float holes, and when the power piston is installed in the power cylinder, the annular anti-deviation groove and the cylinder anti-deviation hole are aligned in the axial direction. The anti-deviation hole of the power piston is disposed on the annular anti-deviation groove. The axial channel is in fluid communication with the anti-deviation hole of the power piston. The axial channel extends from the anti-deviation hole of the power piston along the axial direction of the power piston and leads to the Stirling compression chamber. Thus, the gas in the Stirling compression chamber flows from the axial channel, through the annular anti-deviation groove and the cylinder anti-deviation hole to the back pressure chamber. The cylinder anti-deviation hole, the annular anti-deviation groove, the anti-deviation hole of the power piston and the axial channel form a microchannel to balance the gas pressure of the compression chamber and the back pressure chamber.

2. The Stirling refrigerator as described in claim 1, characterized in that, The number of anti-deviation holes in the power piston is at least 2.

3. The Stirling refrigerator as described in claim 1, characterized in that, The air float holes are arranged along the outer circumferential surface of the power piston, and the number of air float holes per air float hole is 4.

4. The Stirling refrigerator as described in claim 1, characterized in that, The Stirling refrigerator also includes a dynamic vibration absorber structure and a housing assembly, wherein the dynamic vibration absorber structure, cylinder assembly, dynamic piston assembly, and linear motor assembly are all located within the housing assembly; The dynamic vibration absorber structure includes a first dynamic vibration absorber counterweight, a second dynamic vibration absorber counterweight, and a damping plate spring structure. The damping plate spring structure includes a plurality of damping plate spring plates arranged at predetermined intervals. The first dynamic vibration absorber counterweight and the second dynamic vibration absorber counterweight are disposed on the upper and lower sides of the damping plate spring structure.

5. The Stirling refrigerator as described in claim 4, characterized in that, The distance between two adjacent damping plate springs is 1 / 3 of the maximum stroke of a single damping plate spring.

6. The Stirling refrigerator as described in claim 4, characterized in that, The weight of the first dynamic vibration absorber is equal to the weight of the second dynamic vibration absorber.

7. The Stirling refrigerator as described in claim 4, characterized in that, The outer circumferences of the plurality of damping leaf springs arranged at predetermined intervals are fixed to the housing of the housing assembly by screws and damping stators, and the profiles of the plurality of damping leaf springs are arranged in a manner of cross-interference.

8. The Stirling refrigerator as described in claim 1, characterized in that, The linear motor includes, from the inside to the outside, an inner magnetic yoke, a magnetic ring, and an outer magnetic yoke in its radial direction. The outer magnetic yoke has a recess facing the magnetic ring, which is used to wind a coil. A magnetic ring support frame is provided at the lower end of the magnetic ring. The magnetic ring support frame is connected to the power piston. When the energized coil interacts with the magnetic ring, the linear reciprocating motion of the magnetic ring drives the magnetic ring support frame to perform linear reciprocating motion, thereby driving the power piston to perform linear reciprocating motion in the power cylinder.

9. The Stirling refrigerator as described in claim 8, characterized in that, The power leaf spring is connected to the magnetic ring support frame via a first connector.

10. A refrigerator, characterized in that, The refrigerator includes a Stirling refrigerator as described in any one of claims 1-9.

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