CN116641872A

CN116641872A - Piston and compressor

Info

Publication number: CN116641872A
Application number: CN202310441218.XA
Authority: CN
Inventors: 李业林; 贾波; 胡文祥; 史正良; 赖金通; 郑慧芸
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2023-04-23
Filing date: 2023-04-23
Publication date: 2023-08-25

Abstract

The invention relates to the field of compressors, in particular to a piston and a compressor; the piston includes: a piston body having a first axial end formed with a pressurizing end surface for pressurizing fluid in the compression chamber; the pressurizing end face is provided with a sliding hole, and a sliding rod is arranged in the sliding hole; the first end of the slide bar can gradually extend into the compression cavity along with the temperature rise in the compression cavity so as to solve the technical problem of reduced volumetric efficiency caused by the increase of the working frequency rise pressure ratio of the piston compressor.

Description

Piston and compressor

Technical Field

The invention relates to the field of compressors, in particular to a piston and a compressor.

Background

The reciprocating piston compressor has a cylinder head assembly with valve assembly, and a cylinder head to press the valve assembly onto the cylinder seat, and the cylinder head covers the valve assembly to form one sealed cavity. In order to prevent the piston of the piston compressor from being impacted and damaged by the valve assembly in the process of running to the top dead center, the piston connected with one end of the connecting rod generates larger centrifugal force when running under the high-speed working condition, and the crankshaft connected with the other end of the connecting rod also generates larger deformation, so that the impact problem is more serious), and meanwhile, in order to avoid impact noise generated when the compressor impacts the valve assembly and influences the experience of a user, a gap with a certain distance is reserved between the front end surface of the piston and the valve assembly when the piston of the conventional piston compressor is at the top dead center. While the main influencing factor of the volumetric efficiency lambda is the volumetric coefficient lambda _V Coefficient of pressure lambda _P Temperature coefficient lambda _T Leakage coefficient lambda _l I.e. λ=λ _V λ _P λ _T λ _l Wherein the volume coefficient lambda _V The magnitude of the influence of the clearance volume and the compression ratio on the volumetric efficiency is mainly reflected and can be expressed as lambda _V ＝1-c(ε ^1/m -1), wherein c is the clearance volume, ε is the compression ratio, and m is the polytropic exponent, and λ is known to increase with increasing clearance volume and compression ratio _V With a consequent decrease, in particular in the cold regime, i.e. compression ratio vs. lambda _V The influence of (2) is dominant when the volume coefficient is very low; therefore, if the reserved gap is larger, the volumetric efficiency is reduced, and particularly under the working condition of high compression ratio, the volumetric efficiency is reduced more obviously.

For energy saving, some technical means are also proposed in the capacity-variable adjusting technology of small piston compressors, such as the patent CN 110469497A of the grignard electric appliance and the refrigeration equipment with the same, the patent CN 214787931U of the gabexa, an effective cylinder volume for the refrigeration compressor, the electromagnetic capacity-variable device for a compressor cylinder of CN 215256727U, the capacity-variable device for adjusting the effective cylinder volume of the compressor of CN 214787934U, and the capacity-variable structure of CN 112012918A of the piston refrigeration compressor, which are all that a slide valve structure or a rotary valve structure capable of adjusting the volume of the cylinder is additionally arranged on the side of the cylinder seat in the direction of piston motion or the cylinder head at the front end in the direction of piston motion, the position of the slide valve structure can be adjusted by utilizing different pressure gases in the cylinder head under different working conditions, the position of the slide valve structure can also be adjusted by the electromagnetic structure, and the rotary valve structure can be controlled by a micro motor.

However, these structures are improved on the basis of the fit clearance between the piston and the valve assembly at the position where the piston of the original piston compressor is at the top dead center, but the hollow cavity with these slide valve structures is added on the original basis to increase the clearance volume of the compressor, the volume coefficient of the compressor is smaller, and the volumetric efficiency is lower.

Aiming at the technical problems, no better solution exists at present.

Disclosure of Invention

In order to solve the technical problem of reduced volumetric efficiency caused by the increase of the working frequency and the pressure ratio of the piston compressor, a piston and a compressor are provided.

In one aspect, the present invention provides a piston for a piston compressor, the piston compressor being formed with a compression chamber, comprising:

a piston body having a first axial end formed with a pressurizing end surface for pressurizing the fluid in the compression chamber;

the pressurizing end face is provided with a sliding hole, and a sliding rod is arranged in the sliding hole; the first end of the slide bar can gradually extend into the compression cavity along with the temperature rise in the compression cavity.

Preferably, the slide bar gradually tapers back into the slide hole as the temperature in the compression chamber decreases.

Preferably, a heat induction spring is arranged in the sliding hole, a first end of the heat induction spring is fixedly connected with the sliding rod, and a second end of the heat induction spring is fixedly connected with the inner wall surface of the sliding hole;

the length of the heat induction spring can be increased along with the temperature rise in the compression cavity so as to push the first end of the sliding rod to extend into the compression cavity;

and an elastic piece is further arranged in the sliding hole, and the heat induction spring can be stretched to compress the elastic piece.

Preferably, a heat induction spring is arranged in the sliding hole, a first end of the heat induction spring is connected with the sliding rod, and a second end of the heat induction spring is connected with the inner wall surface of the sliding hole;

the length of the heat induction spring can be increased along with the temperature rise in the compression cavity so as to push the first end of the sliding rod to extend into the compression cavity; the length of the heat sensing spring can be shortened along with the temperature reduction in the compression cavity so as to pull the first end of the sliding rod to slide towards the direction back to the compression cavity.

Preferably, the sliding hole is a through hole penetrating through two axial ends of the piston, and one end of the sliding hole, which is far away from the compression cavity, is sealed by a screw; when the sliding rod is arranged in the sliding hole, a first interval is formed between the screw and one end, far away from the compression cavity, of the sliding rod, and the heat induction spring is arranged in the first interval.

Preferably, a buffer portion is disposed at an end of the first end of the slide bar.

Preferably, the inner wall surface of the sliding hole comprises a first step surface facing away from the compression cavity;

the second end of the sliding rod is provided with a rod head, and the rod head is provided with a second step surface facing the first end of the sliding rod; when the sliding rod is inserted into the sliding hole, a second interval is formed between the first step surface and the second step surface, the elastic piece is a mechanical spring, and the mechanical spring is arranged in the second interval and sleeved on the sliding rod.

Preferably, the sliding rod comprises a first rod section and a second rod section, the cross section area of the first rod section is larger than that of the second rod section, and the sliding rod is fixedly connected with the rod head through the second rod section.

Preferably, the club head is provided with a protrusion protruding away from the slide bar.

Preferably, the first rod section and the sliding hole slide in a sealing manner.

On the other hand, the application also provides a compressor comprising the piston.

According to the application, the sliding rod is arranged on the piston, so that the sliding rod can slide towards the compression cavity or slide back to the compression cavity along with the temperature in the compression cavity to change the clearance volume included in the compression cavity, and as the working frequency of the compressor is improved, the temperature in the compression cavity is correspondingly increased, the longer the sliding rod stretches into the compression cavity, the smaller the compression cavity and the clearance volume are, so that adverse effects caused by the increase of the pressure ratio due to the increase of the temperature are reduced, the working efficiency of the compressor is improved, and compared with the increase of the clearance volume caused by the adjustment of the volume of the compression cavity by other electromagnetic structures, the clearance volume is reduced while the size of the compression cavity is adjusted, and the operation efficiency of the compressor is further improved.

Drawings

FIG. 1 is an exploded view of a pump body assembly of a compressor according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a pump body assembly according to an embodiment of the present invention;

FIG. 3 is an exploded view of a piston and accessory according to an embodiment of the present invention;

FIG. 4 is an oblique view of a piston according to an embodiment of the present invention;

FIG. 5 is a cross-sectional view of a piston according to an embodiment of the present invention;

FIG. 6 is an exploded view of a thermally sensitive slide bar assembly according to an embodiment of the present invention;

FIG. 7 is a schematic view showing the relationship between a slide bar and a club head according to an embodiment of the present invention;

FIG. 8 is a schematic view of a slide bar on a piston under low frequency operation in accordance with an embodiment of the present invention;

FIG. 9 is a schematic view of the slide bar on the piston during intermediate frequency operation in accordance with an embodiment of the present invention;

FIG. 10 is a schematic view of a slide bar on a piston under high frequency operation in accordance with an embodiment of the present invention;

FIG. 11 is an enlarged view of the portion K of FIG. 10 according to an embodiment of the present invention;

FIG. 12 is a schematic view of the heat-sensitive spring and the mechanical spring removed at K in FIG. 10 according to an embodiment of the present invention;

FIG. 13 is a graph of actual operating pressure versus volume (P-V) for a piston compressor in accordance with an embodiment of the present invention;

the reference numerals are expressed as:

10. a cylinder block; 20. a planar rolling bearing; 30. a crankshaft assembly; 40. a piston assembly; 41. a piston body; 41a, an outer cylindrical surface; 41b, a slit groove; 41c, inner holes; 41d, upper limit ribs; 41e, lower limit ribs; 41h, sliding holes; 41h-1, large round hole; 41h-2, small round holes; 41h-3, a first step surface; 41f, large pin holes; 41g, small pin holes; 42. a connecting rod; 43. a piston pin; 44. a clamp spring pin; 45. a thermally-induced slide bar assembly; 45a, a slide bar; 45a-1, a first pole segment; 45a-2, a second pole segment; 45b, mechanical springs; 45c, a club head; 45c-1, a base, 45c-2 and a bulge; 45c-3, grooves; 45c-4, a second step surface; 45d, a heat induction spring; 46. a screw; 50. a valve assembly; 51. an air suction valve gasket; 52. a suction valve plate; 53. a valve plate; 54. an exhaust valve plate; 55. an exhaust valve limiting plate; 56. v-shaped clamp springs; 60. a cylinder head; 70. a suction muffler assembly; 2. a compression chamber; 3. pressurizing the end face; 101. a first interval; 102. and a second interval.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, the "plurality" generally includes at least two, but does not exclude the case of at least one.

It should be understood that the term "and/or" as used herein is merely one relationship describing the association of the associated objects, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship; the first and second are used herein only to distinguish between different technical features, and not to have a sequential order; the terms "upper", "lower", "front" and "rear" are also used herein for more convenient description of the positional relationship of the technical features, and they are not absolute positional relationships, but rather have a certain meaning in combination with the actual use condition or the specific azimuth description.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product or system. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a commodity or system comprising such elements.

For reciprocating piston compressors, the pump head assembly of the cylinder thereof is de-suctionBesides the valve components of the air valve and the exhaust valve, the air valve and the exhaust valve also comprise a cylinder cover which is used for pressing and fixing the valve components on the cylinder seat, the cylinder cover completely covers the valve components to form a closed cavity, when the piston reciprocates in the cylinder, the air or refrigerant is compressed and acted, the air or refrigerant is discharged out of the cylinder through the exhaust hole and the exhaust valve and enters and fills the cavity surrounded by the cylinder cover, and the compressed refrigerant is conveyed to the outside of the compressor through the inner exhaust coil pipe and finally enters into a refrigeration cycle system such as a refrigerator. In order to prevent the piston of the piston compressor from being impacted and damaged by the valve assembly in the process of running to the top dead center, the piston connected with one end of the connecting rod generates larger centrifugal force when running under the high-speed working condition, and the crankshaft connected with the other end of the connecting rod also generates larger deformation, so that the impact problem is more serious), and meanwhile, in order to avoid impact noise generated when the compressor impacts the valve assembly and influences the experience of a user, a gap with a certain distance is reserved between the front end surface of the piston and the valve assembly when the piston of the conventional piston compressor is at the top dead center. While the main influencing factor of the volumetric efficiency lambda is the volumetric coefficient lambda _V Coefficient of pressure lambda _P Temperature coefficient lambda _T Leakage coefficient lambda _l I.e. λ=λ _V λ _P λ _T λ _l Wherein the volume coefficient lambda _V The magnitude of the influence of the clearance volume and the compression ratio on the volumetric efficiency is mainly reflected and can be expressed as lambda _V ＝1-c(ε ^1/m -1), wherein c is the clearance volume, ε is the compression ratio, and m is the polytropic exponent, and λ is known to increase with increasing clearance volume and compression ratio _V With a consequent decrease, in particular in the cold regime, i.e. compression ratio vs. lambda _V The influence of (2) is dominant when the volume coefficient is very low; therefore, if the reserved gap is larger, the volumetric efficiency is reduced, and particularly under the working condition of high compression ratio, the volumetric efficiency is reduced more obviously.

In order to solve the technical problem of the reduction of volumetric efficiency caused by the increase of the operating frequency rise-to-pressure ratio of the piston compressor, the present invention provides a piston, as shown in fig. 1-13, for a piston compressor, which is formed with a compression chamber 2, comprising: a piston body 41 having a pressurizing end surface 3 formed at a first axial end thereof, the pressurizing end surface 3 being for pressurizing the fluid in the compression chamber 2; the pressurizing end face 3 is provided with a sliding hole 41h, and a sliding rod 45a is arranged in the sliding hole 41 h; the first end of the slide rod 45a can gradually extend into the compression chamber 2 as the temperature in the compression chamber 2 increases.

The compression chamber 2 comprises a clearance volume, and when the slide rod 45a extends into the compression chamber 2, the slide rod 45a enters the clearance volume; the reduction in the size of the clearance volume by extending the slide bar 45a into the clearance volume at least partially reduces the adverse effect of the increase in pressure ratio on the compressor. The piston compressor is provided with a cylinder hole, and the piston slides in the cylinder hole to compress and apply work to a compression cavity 2 of the compressor; when the compressor operates under the working condition of low frequency and low speed, less heat is generated by mechanical friction, the temperature of compressed gas or refrigerant is low, and the first end of the sliding rod 45a does not or rarely extend into the compression cavity 2; when the first end of the slide rod 45a does not extend into the compression chamber 2, the end face of the first end of the slide rod 45a is flush with the end face of the first end of the piston, avoiding an increase in clearance volume. When the working frequency of the compressor is increased, the running speed of the piston is correspondingly increased, more heat is generated by mechanical friction, the temperature of the compressed gas or refrigerant is higher, and the length of the first end of the sliding rod 45a extending into the clearance volume is larger, so that the clearance volume is reduced. When the compressor is operated under the working condition of the highest frequency and the highest speed, more heat is generated by mechanical friction, the temperature generated by compressed gas or refrigerant reaches the highest, the length of the first end of the sliding rod 45a extending into the compression cavity 2 reaches the longest, the clearance volume reaches the smallest, and the sliding rod 45a gradually retracts into the sliding hole 41h along with the temperature reduction in the compression cavity 2.

That is, the size of the clearance volume decreases with an increase in temperature, the clearance volume is a part of the compression chamber 2, and the size of the compression chamber 2 also decreases with an increase in temperature; volumetric efficiency λ=λ of piston compressor _V ×λ _P ×λ _T ×λ _l . Wherein the volume coefficient lambda _V Reflects the magnitude of the influence of the clearance volume and the compression ratio on the volumetric efficiency, expressed as lambda _V ＝1-c(ε ^1/m -1), c is the clearance volume, ε is the compression ratio, m is the polytropic index, and λ is known to increase with increasing clearance volume and compression ratio _V With a consequent decrease in the volumetric coefficient lambda, especially in high-pressure specific conditions of low-temperature refrigeration _V Lower at this time the compression ratio is against lambda _V And thus in the event of an increase in the temperature in the compression chamber 2 leading to an increase in the compression ratio, the increase in the compression ratio is at least partially reduced by the way the slide bar 45a protrudes into the clearance volume to reduce the size of the clearance volume.

As the working frequency of the compressor is higher, the temperature in the compression cavity 2 is higher, the discharge pressure is higher at a fixed suction pressure, the corresponding pressure ratio (the ratio of absolute discharge pressure to absolute suction pressure) is also higher, the pressure required to be applied when the compressor compresses the gas or refrigerant in the compression cavity 2 is higher, the power consumption of the compressor is higher, and the performance of the compressor is reduced; the reduction of the clearance volume can reduce the adverse effect of the pressure ratio increase on the compressor. The volumetric efficiency of the compressor under the low-frequency working condition is not affected, and the volumetric efficiency under the working conditions of high compression ratios such as medium frequency and high frequency is not reduced.

The second end of the piston is provided with an inner hole 41c of the piston, one end of a connecting rod 42 driving the piston to slide is arranged in the inner hole 41c of the piston, and the inner hole 41c of the piston is provided with an upper limit rib 41d and a lower limit rib 41e for limiting the connecting rod 42; the sliding holes 41h are symmetrically arranged on the planes of the upper limit rib 41d and the lower limit rib 41e about the axis of the piston; due to the structural limitation of the piston, the number of sliding holes 41h is generally even and symmetrically arranged about the axis of the piston.

When the operating frequency of the compressor is lowered, the temperature in the compression chamber 2 is lowered, the pressure ratio is reduced, the slide rod 45a slides toward the slide hole 41h, the clearance volume is increased, the compression chamber 2 is increased, more gas can be sucked for compression, and the compression efficiency is improved.

Preferably, as shown in fig. 6-12, a heat sensing spring 45d is arranged in the sliding hole 41h, a first end of the heat sensing spring 45d is fixedly connected with the sliding rod 45a, and a second end of the heat sensing spring 45d is fixedly connected with the inner wall surface of the sliding hole 41 h; the length of the heat sensing spring 45d can be increased as the temperature in the compression chamber 2 increases to push the first end of the slide bar 45a to extend into the compression chamber 2.

An elastic member is further provided in the slide hole 41h, and is compressed when the heat sensitive spring 45d is extended. The elastic member may employ a mechanical spring 45b made of spring steel; the heat-sensitive spring 45d is made of a one-way memory alloy, and the memory alloy is binary memory alloy or ternary memory alloy; the binary memory alloy or the ternary memory alloy is Ni-Ti system or Cu-based system or Fe-based system, the austenite temperature line Ac of the memory alloy is in the range of the operation temperature of the compressor, the operation temperature range of the compressor is generally room temperature to 200 ℃, when the temperature in the compression cavity 2 is higher than the temperature line Ac, the memory alloy is gradually transformed from a martensite phase to an austenite phase, and at the moment, the heat induction spring 45d is stretched and the mechanical spring 45b is compressed to store elastic potential energy; when the ambient temperature decreases, the heat sensing spring 45d cannot automatically contract, and at this time, the compressed mechanical spring 45b releases elastic potential energy and slides the slide rod 45a toward the slide hole 41h, and at the same time, the slide rod 45a contracts the heat sensing spring 45 d. The one-way memory alloy has low price, the mechanical spring reacts rapidly, and the heat sensing spring 45d can be made of the one-way memory alloy by making the heat sensing spring 45d and the mechanical spring 45b, so that the cost is reduced; on the other hand, the mechanical spring 45b deforms more rapidly, and the movement of the slide bar 45a can be accelerated.

Preferably, a heat sensing spring 45d is arranged in the sliding hole 41h, a first end of the heat sensing spring 45d is connected with the sliding rod 45a, and a second end of the heat sensing spring 45d is connected with the inner wall surface of the sliding hole 41h; the length of the heat sensing spring 45d can be increased along with the temperature rise in the compression chamber 2 so as to push the first end of the sliding rod 45a to extend into the compression chamber 2; the length of the heat sensing spring 45d can be shortened as the temperature in the compression chamber 2 decreases to pull the first end of the slide bar 45a to slide in a direction away from the compression chamber 2. The heat-sensitive spring 45d is made of the double-way memory alloy, the ambient temperature is increased, the heat-sensitive spring 45d is elongated, the ambient temperature is reduced, and the heat-sensitive spring 45d is shortened; the mechanical spring can be eliminated by adopting the double-way memory alloy, the structure is simplified, and the production efficiency is improved.

Preferably, as shown in fig. 11-12, the sliding hole 41h is a through hole penetrating through two axial ends of the piston, and one end of the sliding hole 41h far from the compression chamber 2 is sealed by a screw 46; when the slide rod 45a is disposed in the slide hole 41h, a first space 101 is formed between the screw 46 and an end of the slide rod 45a remote from the compression chamber 2, and the heat sensitive spring 45d is disposed in the first space 101.

The heat sensing spring 45d is arranged in the first interval 101 and stretches or shortens along with the temperature change in the compression cavity 2, and since the first interval 101 is arranged at the end part of the sliding rod 45a, on one hand, the heat sensing spring 45d is arranged at one axial end, so that a buffer effect is generated when the sliding rod collides with a valve assembly in the compression cavity 2, and the sliding rod 45a is prevented from bending and not retracting into the sliding hole 41h; on the other hand, the cross-sectional area of the slide bar 45a can be made as large as possible within the allowable range, and when the first end of the slide bar 45a extends into the compression chamber 2 for a certain length, the larger the cross-sectional area is, the larger the size range of the adjustable clearance volume is, and the adverse effect of the pressure ratio rise on the compressor is further reduced.

Preferably, the end of the first end of the slide bar 45a is provided with a buffer.

A polymer layer may be coated at the end of the first end of the slide bar 45a to form a buffer, such as polytetrafluoroethylene; the buffer portion can effectively avoid impact noise and vibration caused by the impact of the slide rod 45a on the valve assembly due to unexpected conditions (the slide rod 45a has a tendency to move forward due to inertial force when the piston moves in the top dead center direction). The screw 46 is an internally countersunk screw 46, and a sealant or an adhesive may be applied to the threaded portion of the screw 46 to ensure sealing.

Preferably, as shown in fig. 6 to 7, the inner wall surface of the sliding hole 41h includes a first stepped surface 41h-3 facing away from the compression chamber 2; the second end of the slide bar 45a is provided with a head 45c, and the head 45c is formed with a second step surface 45c-4 facing the first end of the slide bar 45 a; when the slide bar 45a is inserted into the slide hole 41h, a second space 102 is formed between the first step surface 41h-3 and the second step surface 45c-4, the elastic member is a mechanical spring 45b, and the mechanical spring 45b is disposed in the second space 102 and sleeved on the slide bar 45 a.

The rod head 45c has a guiding function on the sliding rod 45a in the sliding hole 41h, so that the sliding rod 45a is prevented from being blocked in the sliding hole 41 h. Meanwhile, the first step surface 41h-3 formed by the rod head 45c has a limiting effect on the mechanical spring 45b, so that the mechanical spring 45b can conveniently apply work to the slide rod 45 a. The mechanical spring 45b is arranged in the second interval 102 and sleeved on the sliding rod 45a, and two ends of the mechanical spring 45b are respectively abutted against the first step surface 41h-3 and the second step surface 45c-4; the mechanical spring 45b is adopted, and the mechanical spring 45b is sleeved on the sliding rod 45a, so that the cross section area of the sliding hole 41h can be reduced, the occupation of the sliding hole 41h on a piston entity is reduced, and the rigidity of the piston is ensured; while ensuring the rigidity of the piston, the cross-sectional area of the slide rod 45a can be made as large as possible, when the first end of the slide rod 45a extends into the compression chamber 2 for a certain length, the larger the cross-sectional area is, the larger the size range of the adjustable clearance volume is, and the adverse effect of the pressure ratio rise on the compressor is further reduced.

A groove 45c-3 may be provided on the head 45c, and one end of the slide bar 45a is inserted into the groove 45c-3 with interference; in the radial direction of the slide bar 45a, the cross section area of the slide bar 45a4 is smaller than that of the rod head 45c, and in actual processing, the slide bar 45a4 and the rod head 45c are respectively processed, so that the material consumption can be reduced, and the cost can be reduced.

Preferably, as shown in FIG. 7, the slide bar 45a includes a first bar section 45a-1 and a second bar section 45a-2, the cross-sectional area of the first bar section 45a-1 being greater than the cross-sectional area of the second bar section 45a-2, the slide bar being fixedly coupled to the club head 45c via the second bar section 45 a-2.

The cross-sectional area of the first rod section 45a-1 is larger than that of the second rod section 45a-2, so that the weight of the sliding rod 45a is reduced and the sliding sensitivity of the sliding rod 45a under the action of the heat sensing spring 45d and the mechanical spring 45b is improved while the effective adjustment of the clearance volume of the sliding rod 45a is ensured.

Preferably, as shown in FIG. 7, the head 45c is provided with a protrusion 45c-2 protruding away from the slide bar 45a 4.

When the heat sensing spring 45d is arranged in the first interval 101, one end of the heat sensing spring 45d is sleeved on the protrusion 45c-2, the protrusion 45c-2 forms a radial positioning function on the heat sensing spring 45d, so that the heat sensing spring 45d is prevented from shaking in the first interval 101, and the stability of the heat sensing spring 45d driving the sliding rod 45a to move is improved. The length of the protrusion 45c-2 can be extended and the length of the screw 46 screwed in can be adjusted, and when the protrusion 45-c abuts against the screw 46, the mechanical spring 45b has a certain elastic force so that the protrusion 45-c keeps in contact with the screw 46, and the end face of the first end of the slide bar 45a is flush with the pressing end face 3 of the piston.

Preferably, the first rod segment 45a-1 is sealingly slid with the sliding aperture 41 h.

The first rod section 45a-1 and the sliding hole 41h are sealed and slide, so that communication between the inside of the sliding hole 41h and the compression cavity 2 is avoided, further, the increase of the clearance volume caused by the arrangement of the sliding hole 41h is avoided, and the performance of the compressor is improved.

The invention also provides a compressor comprising the piston.

As shown in fig. 1 to 13, the pump body assembly of the compressor includes a cylinder block 10, a planar rolling bearing 20, a crankshaft assembly 30, a piston assembly 40, a valve assembly 50, a cylinder head 60, and a suction muffler assembly 70. The crankshaft assembly 30 is disposed in the shaft hole of the cylinder block 10, and the plane rolling bearing 20 is disposed between the crankshaft assembly 30 and the cylinder block to avoid abrasion between the bearing seat of the cylinder block 10 and the crankshaft assembly 30, so that sliding friction is changed into rolling friction, and friction power consumption is reduced. The piston main body 41 of the piston assembly 40 and the small shaft hole of the connecting rod 42 are connected together by a piston pin 43, the piston pin 43 is assembled in a through hole big pin hole 41f, the piston pin 43 is limited and fixed on the piston main body 41 by a clamp spring pin 44, the clamp spring pin 44 is assembled in a blind hole small pin hole 41g, the big shaft hole of the connecting rod 42 is connected with the eccentric crank position of the crank assembly 30, and the motor drives the crank assembly 30 to drive the piston assembly 40 to do reciprocating rectilinear motion in the compression cavity of the cylinder seat 10 so as to do compression work on sucked gas or refrigerant. The valve assembly 50 comprises an air suction valve plate 52, an air discharge valve gasket 51, an air suction valve plate 53, an air discharge valve plate 54, an air discharge valve limiting plate 55 and a V-shaped clamp spring 56, and the fixed cylinder cover 60 not only can press the valve assembly 50 to enable the compression cavity of the cylinder seat 10 to form a closed cavity, but also can press the air discharge valve limiting plate 50 and the V-shaped clamp spring 56 of the valve assembly 50, so that the air discharge valve plate 54 is subjected to lift limiting. Wherein, the suction valve gasket 51 and the exhaust valve gasket 51 are respectively arranged between the cylinder seat 10 and the suction valve plate 52 and between the valve plate 53 and the cylinder cover 60, so as to enhance the sealing performance between the valve assembly 50 and the cylinder seat and between the valve assembly 50 and the cylinder cover 60. A suction muffler assembly 70 is provided at a suction front end of the valve assembly 50, and the suction muffler assembly 70 can reduce pulsation noise of a gas flow generated by a gas or a refrigerant sucked into the compression chamber through the suction port. As shown in fig. 4, the outer cylindrical surface 41a of the piston body 41 of the piston assembly 40 is provided with a notch groove 41b for storing lubricating oil and reducing the contact area between the piston body 41 and the cylinder wall of the cylinder block 10, thereby achieving the purpose of reducing friction power consumption. An upper limit rib 41d and a lower limit rib 41e are arranged in an inner hole 41c of the piston main body 41, so that the overall strength of the piston main body 41 is enhanced, and meanwhile, small pin holes 41g and sliding holes are formed in the two limit ribs. A through hole large pin hole 41f is formed in the outer cylindrical surface 41a of the piston body 41, and a piston pin 43 can be inserted into the large pin hole 41f, so that the piston body 41 and the connecting rod 42 form a rotatable hinge structure. A blind hole small pin hole 41g is formed in the plane of the upper limit rib 41d, and the small pin hole 41g is turned into the clamp spring pin 44 to prevent the piston pin 43 from freely moving in the large pin hole 41 f.

The operation of the compressor at different operating frequencies is described below.

As shown in fig. 6, the slide bar 45a, the mechanical spring 45b, the rod head 45c and the heat sensing spring 45d together form a heat sensing slide bar assembly 45, and the heat sensing slide bar assembly 45 is fixedly limited in the sliding hole 41h by an inner countersunk head screw 46. The sliding hole comprises a large round hole 41h-1 and a small round hole 41h-2, and the large round hole 41h-1 and the small round hole 41h-2 are connected through a first step surface.

As shown in FIG. 7, one end of the slide bar 45a is a first bar section 45a-1 and the other end of the slide bar 45a is a small second bar section 45a-2. One end of the club head 45c is a base 45c-1, the other end of the club head 45c is a protrusion 45c-2, a groove 45c-3 is formed in the plane of the base 45c-1, and the club head 45c can slide in the axial direction of the sliding hole 41 h. The second leg 45a-2 of the slide bar 45a is then press-fit into the recess 45c-3 of the abutment 45c-1 of the club head 45 c.

As shown in fig. 3, 4, 5 and 6, the assembly sequence of the heat-sensitive slide bar assembly 45 is that the mechanical spring 45b is installed at one end of the slide bar 45a toward the end of the slide bar 45a in the assembly composed of the slide bar 45a and the head 45c which are press-fitted, then the pressed slide bar 45a and the head 45c and the assembly with the mechanical spring 45b are assembled into the slide hole 41h, then the heat-sensitive spring 45d is also installed into the slide hole 41h, and finally the inner countersunk head screw 46 is assembled and fixed at the tail part in the slide hole 41 h.

Wherein, the first rod section 45a-1 end of the sliding rod 45a of the heat sensing sliding rod assembly 45 is inserted into the small round hole 41h-2 at the front end of the sliding hole 41h of the piston main body 41, one end of the mechanical spring 45b is abutted against the plane of the base 45c-1 of the rod head 45c, the other end of the mechanical spring 45b is abutted against the first step surface 41h-3 between the large round hole 41h-1 and the small round hole 41h-2 of the sliding hole 41h, one end of the heat sensing spring 45d is abutted against the large base surface of the rod head 45c provided with the protrusion 45c-2, and the other end of the heat sensing spring 45d is abutted against the plane of the inner countersunk screw 46.

Further, in order to prevent the sealing performance of the piston main body 41 from being adversely affected after the heat-sensitive slide bar assembly 45 is installed, an adhesive is applied before the inner countersunk screw 46 is fitted into the slide hole 41 h.

The base material of the heat-sensitive spring is made of memory alloy, and the material of the mechanical spring is made of spring steel. Wherein the memory alloy also has Shape Memory Effect (SME) and Superelasticity (SE).

Further, the memory alloy is one of a binary memory alloy or a ternary memory alloy, and the binary memory alloy or the ternary memory alloy is one of a Ni-Ti system or a Cu system or an Fe system. Wherein the austenite temperature line Ac of the selected memory alloy is within a range of operating temperatures of the compressor, which is about room temperature to about 200 ℃. When the temperature in the compressor is higher than the austenite temperature line Ac, the memory alloy gradually changes from the martensite phase to the austenite phase; when the temperature in the compressor is lower than the austenite temperature line Ac, the memory alloy gradually changes from austenite phase to martensite phase, so as to achieve the purpose of deforming, extending and contracting the heat-sensitive spring.

As shown in fig. 8, when the compressor is operated under the low frequency and low speed condition, the temperature generated by the compressed gas or refrigerant and the temperature generated by the mechanical friction are relatively low, the temperature does not reach the austenite temperature line Ac of the base material memory alloy of the heat sensing spring 45b, the mechanical spring 45b is in a compressed state, the heat sensing spring 45d is in an extended state, so that the end face 45a-3 of the first rod section of the slide rod 45a is flush with the end face of the first end of the piston main body 41, that is, the first rod section 45a-1 of the slide rod 45a is still completely located in the small round hole 41h-2 of the sliding hole 41h of the piston main body 41, and the volume of the compressor is V1. At this time, as shown in fig. 13, the pressure-volume (P-V) of the piston compressor in actual operation is shown in fig. 13, the suction process is shown as a curve 4-1, the compression process is shown as a curve 1-2, the discharge process is shown as a curve 2-3, and the expansion process is shown as a curve 3-4, i.e., the P-V of the piston compressor in operation is changed into a closed loop curve 4 ～ 1 ～ 2 ～ 3 which is repeatedly circulated.

As shown in fig. 9, when the compressor is operated under the medium-frequency and medium-speed working condition, the temperature generated by the compressed gas or refrigerant and the temperature generated by the mechanical friction gradually increase, and the temperature is slightly greater than the austenite temperature line Ac of the base material memory alloy of the heat sensing spring 45d, the heat sensing spring 45d gradually expands, the mechanical spring 45b gradually contracts, so that the sliding rod 45a gradually extends out of the first end of the piston body 41, that is, the first rod section 45a-1 of the sliding rod 45a gradually extends into the compression chamber from the small round hole 41h-2 of the sliding hole 41h of the piston body 41, during which the heat sensing spring 45d starts to exert the Shape Memory Effect (SME) of the memory alloy, and at this time the volume of the compressor in the compressor is V2. While the main influencing factor of the volumetric efficiency lambda of the piston compressor is the volumetric coefficient lambda _V Coefficient of pressure lambda _P Temperature coefficient lambda _T Leakage coefficient lambda _l I.e. λ=λ _V λ _P λ _T λ _l Wherein the volume coefficient lambda _V The magnitude of the influence of the clearance volume and the compression ratio on the volumetric efficiency is mainly reflected and can be expressed as lambda _V ＝1-c(ε ^1/m -1), wherein c is the clearance volume, ε is the compression ratio, and m is the polytropic exponent, and λ is known to increase with increasing clearance volume and compression ratio _V With a consequent decrease in the volumetric coefficient lambda, especially in high-pressure specific conditions of low-temperature refrigeration _V Lower, i.e. when the compression ratio is against lambda _V In the case of an increase in the compression ratio, the adverse effects of the increase in the pressure ratio are partially or completely counteracted by a reduction in the size of the clearance volume, i.e. the volume V2 < V1 of the compression chamber is such that the increase in the pressure ratio is relative to the volume coefficient lambda _V The influence of (c) is gradually reduced and the volumetric efficiency lambda of the compressor is only slightly adversely affected or not at all. At this time, as shown in fig. 13, the pressure-volume (P-V) of the piston compressor in actual operation is shown in fig. 13, the suction process is shown as a curve 4' to 1, the compression process is shown as a curve 1 to 2', the discharge process is shown as a curve 2' to 3, and the expansion process is shown as a curve 3 to 4', i.e., the P-V of the piston compressor in operation is changed into a closed loop curve 4' to 1 ' to 2' to 3 which is repeatedly circulated.

As shown in FIG. 12When the compressor is operated under the working condition of high frequency and high speed, the temperature generated by compressed gas or refrigerant and the temperature generated by mechanical friction reach the highest, the temperature is much higher than the austenite temperature line Ac of the base material memory alloy of the heat sensing spring 45d, the heat sensing spring 45d is in a fully extended state, the mechanical spring 45b is in a fully contracted state, so that the sliding rod 45a extends out of the first end of the piston main body 41 to the maximum extent, namely the first rod section 45a-1 of the sliding rod 45a extends into the compression cavity from the small round hole 41h-2 of the sliding hole 41h of the piston main body 41 to the maximum extent, the heat sensing spring 45d fully plays the role of the Shape Memory Effect (SME) of the memory alloy in the process, and the volume of the compressor in the compressor is V3. While the main influencing factor of the volumetric efficiency lambda of the piston compressor is the volumetric coefficient lambda _V Coefficient of pressure lambda _P Temperature coefficient lambda _T Leakage coefficient lambda _l I.e. λ=λ _V λ _P λ _T λ _l Wherein the volume coefficient lambda _V The magnitude of the influence of the clearance volume and the compression ratio on the volumetric efficiency is mainly reflected and can be expressed as lambda _V ＝1-c(ε ^1/m -1), wherein c is the clearance volume, ε is the compression ratio, and m is the polytropic exponent, and λ is known to increase with increasing clearance volume and compression ratio _V With a consequent decrease in the volumetric coefficient lambda, especially in high-pressure specific conditions of low-temperature refrigeration _V Lower, i.e. when the compression ratio is against lambda _V In the case of an increase in the compression ratio, the adverse effects of the increase in the pressure ratio are partially or completely counteracted by a reduction in the size of the clearance volume, i.e. the volume V2 < V1 of the compression chamber is such that the increase in the pressure ratio is relative to the volume coefficient lambda _V The influence of (c) is gradually reduced and the volumetric efficiency lambda of the compressor is only slightly adversely affected or not at all. At this time, as shown in FIG. 13, the pressure-volume (P-V) of the piston compressor in actual operation is shown as curves 4 ' to 1 in the suction process and curves 1 to 2 in the compression process, the exhaust process is the curves 2 ' -3, the expansion process is the curves 3-4 ', i.e. the P-V change of the operation of the piston compressor is the closed loop curves 4 ' -1-2 ' -3 of the repeated circulation.

When the piston compressor is turned from high frequency to low frequency or is turned from high frequency/medium frequency to stop directly, the heat sensing spring 45d does not have a trend of extending any more, but has a trend of recovering the original contracted state, so that no force is generated on the mechanical spring 45b any more, the force generated by the heat sensing spring 45d is smaller than the force generated by the mechanical spring 45b, the heat sensing spring 45d is gradually compressed by the force of the mechanical spring 45b until the heat sensing spring 45d is completely compressed and recovered to the original contracted state, and the heat sensing spring 45b plays a role of Super Elasticity (SE) of the memory alloy in the process.

In another embodiment, on the basis of fig. 6, the heat-sensitive spring 45d and the mechanical spring 45b are arranged in opposite positions, the heat-sensitive spring 45d is heated to be shortened, and the mechanical spring 45b is stretched. The austenite temperature line Ac of the memory alloy is selected to be within the operating temperature range of the compressor, which is approximately room temperature to 200 c. When the temperature in the compressor is higher than the austenite temperature line Ac, the memory alloy gradually changes from the martensite phase to the austenite phase; when the temperature in the compressor is lower than the austenite temperature line Ac, the memory alloy gradually changes from the austenite phase to the martensite phase, so that the purpose of deforming and shrinking the heat-sensitive spring is achieved.

The process comprises the following steps:

when the compressor is operated under the working condition of low frequency and low speed, the temperature generated by compressed gas or refrigerant and the temperature generated by mechanical friction are relatively low, the temperature does not reach the austenite temperature line Ac of the base material memory alloy of the heat sensing spring 45b, the heat sensing spring 45b is in an extension state, the mechanical spring 45d is in a compression state, the end face 45a-3 of the first end of the sliding rod 45a is flush with the first end face of the piston main body 41, namely, the first rod section 45a-1 of the sliding rod 45a is completely positioned in the small round hole 41h-2 of the sliding hole 41h of the piston main body 41, and the volume of the compressor is V1. At this time, as shown in fig. 13, the pressure-volume (P-V) of the piston compressor in actual operation is shown in fig. 13, the suction process is shown as a curve 4-1, the compression process is shown as a curve 1-2, the discharge process is shown as a curve 2-3, and the expansion process is shown as a curve 3-4, i.e., the P-V of the piston compressor in operation is changed into a closed loop curve 4 ～ 1 ～ 2 ～ 3 which is repeatedly circulated.

When the compressor operates under the working condition of medium frequency and medium speed, the temperature generated by compressed gas or refrigerant and the temperature generated by mechanical friction are gradually increased, the temperature is slightly larger than the austenite temperature line Ac of the base material memory alloy of the heat sensing spring 45b, the heat sensing spring 45b is gradually contracted, the mechanical spring 45d is gradually extended, the sliding rod 45a is gradually extended out of the front end face of the piston main body 41, namely, the first rod section 45a-1 of the sliding rod 45a is gradually extended into the compression cavity from the small round hole 41h-2 of the sliding hole 41h of the piston main body 41, the heat sensing spring 45b starts to play the role of the Shape Memory Effect (SME) of the memory alloy in the process, and the volume of the compressor in the compressor is V2. While the main influencing factor of the volumetric efficiency lambda of the piston compressor is the volumetric coefficient lambda _V Coefficient of pressure lambda _P Temperature coefficient lambda _T Leakage coefficient lambda _l I.e. λ=λ _V λ _P λ _T λ _l Wherein the volume coefficient lambda _V The magnitude of the influence of the clearance volume and the compression ratio on the volumetric efficiency is mainly reflected and can be expressed as lambda _V ＝1-c(ε ^1/m -1), wherein c is the clearance volume, ε is the compression ratio, and m is the polytropic exponent, and λ is known to increase with increasing clearance volume and compression ratio _V With a consequent decrease in the volumetric coefficient lambda, especially in high-pressure specific conditions of low-temperature refrigeration _V Lower, i.e. when the compression ratio is against lambda _V In the case of an increase in the compression ratio, the adverse effects of the increase in the pressure ratio are partially or completely counteracted by a reduction in the size of the clearance volume, i.e. the volume V2 < V1 of the compression chamber is such that the increase in the pressure ratio is relative to the volume coefficient lambda _V The influence of (c) is gradually reduced and the volumetric efficiency lambda of the compressor is only slightly adversely affected or not at all. At this time, as shown in fig. 10, the pressure-volume (P-V) of the piston compressor in actual operation is shown in fig. 10, the suction process is shown as a curve 4' to 1, the compression process is shown as a curve 1 to 2', the discharge process is shown as a curve 2' to 3, and the expansion process is shown as a curve 3 to 4', i.e., the P-V of the piston compressor in operation is changed into a closed loop curve 4' to 1 ' to 2' to 3 which is repeatedly circulated.

As shown in fig. 12, when the compressor is operated under the high-frequency and high-speed working condition, the temperature generated by the compressed gas or refrigerant and the temperature generated by the mechanical friction reach the highest, and the temperature is much higher than the austenite temperature line Ac of the base material memory alloy of the heat sensing spring 45b, the heat sensing spring 45b is in a fully contracted state, the mechanical spring 45d is in a fully extended state, so that the sliding rod 45a extends out of the first end of the piston body 41 to the maximum extent, that is, the first rod section 45a-1 of the sliding rod 45a extends into the compression cavity from the small round hole 41h-2 of the sliding hole 41h of the piston body 41, during which the heat sensing spring 45b fully exerts the Shape Memory Effect (SME) of the memory alloy, and the volume of the compressor in the compressor is V3. While the main influencing factor of the volumetric efficiency lambda of the piston compressor is the volumetric coefficient lambda _V Coefficient of pressure lambda _P Temperature coefficient lambda _T Leakage coefficient lambda _l I.e. λ=λ _V λ _P λ _T λ _l Wherein the volume coefficient lambda _V The magnitude of the influence of the clearance volume and the compression ratio on the volumetric efficiency is mainly reflected and can be expressed as lambda _V ＝1-c(ε ^1/m -1), wherein c is the clearance volume, ε is the compression ratio, and m is the polytropic exponent, and λ is known to increase with increasing clearance volume and compression ratio _V With a consequent decrease in the volumetric coefficient lambda, especially in high-pressure specific conditions of low-temperature refrigeration _V Lower, i.e. when the compression ratio is against lambda _V In the case of an increase in the compression ratio, the adverse effects of the increase in the pressure ratio are partially or completely counteracted by a reduction in the size of the clearance volume, i.e. the volume V2 < V1 of the compression chamber is such that the increase in the pressure ratio is relative to the volume coefficient lambda _V The influence of (c) is gradually reduced and the volumetric efficiency lambda of the compressor is only slightly adversely affected or not at all. At this time, as shown in FIG. 13, the pressure-volume (P-V) of the piston compressor in actual operation is shown as curves 4 ' to 1 in the suction process and curves 1 to 2 in the compression process, the exhaust process is the curves 2 ' -3, the expansion process is the curves 3-4 ', i.e. the P-V change of the operation of the piston compressor is the closed loop curves 4 ' -1-2 ' -3 of the repeated circulation.

When the piston compressor is turned from high frequency to low frequency or is turned from high frequency/medium frequency to stop directly, the heat-sensitive spring 45b is contracted to a limit state and gradually returns to an original extended state, and the force generated by the heat-sensitive spring 45b is larger than that of the mechanical spring 45d, so that the mechanical spring 45d is gradually compressed by the force of the heat-sensitive spring 45b until the mechanical spring 45d is completely compressed and returns to an original contracted state, and the heat-sensitive spring 45b plays a role of Super Elasticity (SE) of the memory alloy in the process.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention. The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that modifications and variations can be made without departing from the technical principles of the present invention, and these modifications and variations should also be regarded as the scope of the invention.

Claims

1. A piston for a piston compressor, the piston compressor being formed with a compression chamber (2), characterized by comprising:

A piston body (41) having a first axial end formed with a pressurizing end surface (3), the pressurizing end surface (3) being for pressurizing the fluid in the compression chamber (2);

a sliding hole (41 h) is formed in the pressurizing end face (3), and a sliding rod (45 a) is arranged in the sliding hole (41 h); the first end of the sliding rod (45 a) can gradually extend into the compression cavity (2) along with the temperature rise in the compression cavity (2).

2. Piston according to claim 1, characterized in that the slide rod (45 a) tapers back into the slide hole (41 h) gradually as the temperature in the compression chamber (2) decreases.

3. The piston according to claim 2, wherein a heat-sensitive spring (45 d) is arranged in the sliding hole (41 h), a first end of the heat-sensitive spring (45 d) is fixedly connected with the sliding rod (45 a), and a second end of the heat-sensitive spring (45 d) is fixedly connected with an inner wall surface of the sliding hole (41 h);

the length of the heat induction spring (45 d) can be increased along with the temperature rise in the compression cavity (2) so as to push the first end of the sliding rod (45 a) to extend into the compression cavity (2);

an elastic piece is further arranged in the sliding hole (41 h), and the heat induction spring (45 d) can be stretched to compress the elastic piece.

4. The piston according to claim 1, wherein a heat-sensitive spring (45 d) is arranged in the sliding hole (41 h), a first end of the heat-sensitive spring (45 d) is connected with the sliding rod (45 a), and a second end of the heat-sensitive spring (45 d) is connected with an inner wall surface of the sliding hole (41 h);

the length of the heat induction spring (45 d) can be increased along with the temperature rise in the compression cavity (2) so as to push the first end of the sliding rod (45 a) to extend into the compression cavity (2); the length of the heat sensing spring (45 d) can be shortened along with the temperature reduction in the compression cavity (2) so as to pull the first end of the sliding rod (45 a) to slide towards the direction back to the compression cavity (2).

5. A piston according to claim 3, wherein the sliding hole (41 h) is a through hole penetrating through both axial ends of the piston, and an end of the sliding hole (41 h) remote from the compression chamber (2) is sealed by a screw (46); when the sliding rod (45 a) is arranged in the sliding hole (41 h), a first interval (101) is formed between the screw (46) and one end, far away from the compression cavity (2), of the sliding rod (45 a), and the heat induction spring (45 d) is arranged in the first interval (101).

6. Piston according to claim 5, characterized in that the end of the first end of the slide rod (45 a) is provided with a buffer.

7. Piston according to claim 5, characterized in that the inner wall surface of the sliding bore (41 h) comprises a first step surface (41 h-3) facing away from the compression chamber (2);

a second end of the sliding rod (45 a) is provided with a rod head (45 c), and the rod head (45 c) is provided with a second step surface (45 c-4) facing the first end of the sliding rod (45 a); when the sliding rod (45 a) is inserted into the sliding hole (41 h), a second interval (102) is formed between the first step surface (41 h-3) and the second step surface (45 c-4), the elastic piece is a mechanical spring (45 b), and the mechanical spring (45 b) is arranged in the second interval (102) and sleeved on the sliding rod (45 a).

8. The piston of claim 7 wherein said slide bar (45 a) comprises a first rod section (45 a-1) and a second rod section (45 a-2), said first rod section (45 a-1) having a cross-sectional area greater than said second rod section (45 a-2), said slide bar (45 a) being fixedly connected to said head (45 c) via said second rod section (45 a-2).

9. The piston according to claim 8, wherein the head (45 c) is provided with a projection (45 c-2) projecting away from the slide bar (45 a).

10. A compressor comprising a piston according to any one of claims 1 to 9.