A pump body assembly and a compressor having the same

Abstract

The application provides a pump body assembly and a compressor with the same, and the pump body assembly comprises a cylinder base, a piston and a valve plate assembly; the cylinder base is provided with a cylinder hole; the valve plate assembly is connected with the cylinder base, the valve plate assembly is provided with an exhaust hole, and the exhaust hole is communicated with the cylinder hole; the valve plate assembly comprises a valve piece, and the valve piece covers the exhaust hole; the piston is provided with a first end face facing the exhaust hole, the first end face is provided with an elastic piece, and the piston is movably arranged in the cylinder hole, so that the elastic piece extends into the exhaust hole or is away from the exhaust hole. Under the action of the elasticity of the elastic piece, the valve piece is timely closed, the problems of backflow and delayed closing of the exhaust hole are improved, and the working efficiency of the valve plate assembly is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of compressor, in particular to a pump body assembly and a compressor with the same. BACKGROUND

[0002] The piston is one of the core components of the refrigerator compressor, and the structure design and material composition thereof play a decisive role in the performance, cooling capacity and reliability of the compressor. With the increasing requirement on the efficiency level of the compressor, the compressor is operated at a wide frequency and high speed, and the conventional piston structure and material will cause serious heat and wear between the piston and the cylinder and noise problems at high speed operation, which cannot meet the use requirement of the development of the compressor. When the compressor is operated at a high frequency, the exhaust hole of the compressor exists backflow and delayed closing of exhaust gas when the compressor exhausts, which affects the performance level of the compressor. SUMMARY

[0003] The present application provides a pump body assembly and a compressor with the same, which can solve the technical problem that the exhaust hole of the compressor exists backflow and delayed closing of exhaust gas when the compressor exhausts.

[0004] The present application provides a pump body assembly, which comprises a cylinder seat, a piston and a valve plate assembly.

[0005] The cylinder seat is provided with a cylinder hole.

[0006] The valve plate assembly is connected with the cylinder seat, the valve plate assembly is provided with an exhaust hole, the exhaust hole is communicated with the cylinder hole, the valve plate assembly comprises a valve sheet, and the valve sheet covers the exhaust hole.

[0007] The piston has a first end face facing the exhaust hole, the first end face is provided with an elastic member, and the piston is movably arranged in the cylinder hole, so that the elastic member extends into the exhaust hole or away from the exhaust hole.

[0008] In some embodiments, the piston is made of ceramic material.

[0009] In some embodiments, the gap between the piston and the cylinder hole is 4-6um.

[0010] In some embodiments, the piston is movably arranged along the axis of the cylinder hole, the cylinder hole is provided with a coating layer, the radial outer edge of the piston has a gap with the coating layer, and the coating layer has the same thermal expansion coefficient as the piston.

[0011] In some embodiments, the pump body assembly further comprises a piston pin and a connecting rod, the connecting rod and the piston have a pin shaft hole, the piston pin is arranged in the pin shaft hole, so that the connecting rod is connected with the piston.

[0012] The outer wall of the piston pin is provided with an oil storage groove or the inner wall of the pin hole is provided with an oil storage groove.

[0013] In some embodiments, the oil storage groove is provided on the inner wall of the pin hole of the piston, and the oil storage groove is in a spiral shape.

[0014] In some embodiments, the piston pin is made of a ceramic material, or both the piston pin and the piston are made of a ceramic material.

[0015] In some embodiments, the elastic member is a spring, the elastic member is arranged on the axis of the exhaust hole, and in the radial direction of the exhaust hole, the diameter of the elastic member is smaller than the diameter of the exhaust hole.

[0016] In some embodiments, the material composition of the ceramic material is AlSiC, wherein the raw materials of the ceramic material include SiC and Al in percentage by mass, the percentage by mass of SiC is greater than 70%, and Al is a sintering aid.

[0017] A compressor comprising a pump body assembly, the pump body assembly being the pump body assembly described above.

[0018] The pump body assembly and the compressor with the pump body assembly have the following beneficial effects:

[0019] The elastic member is arranged on the first end surface of the piston, and compared with the valve plate being bent only by the exhaust pressure, the elastic member arranged in the embodiment provides an external force to the valve plate, pushes the valve plate to open, improves the opening force of the valve plate, makes the exhaust opening more timely, and after the exhaust is completed, the valve plate will be closed in time under the action of the elastic force of the elastic member, improves the backflow and the exhaust hole delayed closing problem, and improves the working efficiency of the valve plate assembly. Moreover, the movement process of the elastic member is related to the reciprocating motion of the piston, fully combines the motion law of the piston, and does not need to arrange an additional moving part to drive the elastic member to move. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only exemplary, and those skilled in the art can also obtain other embodiment drawings according to the provided drawings without creating any creative labor.

[0021] Figure 1 It is a schematic view of the pump body assembly of the embodiment of the present application;

[0022] Figure 2 It is a sectional view of the pump body assembly of the embodiment of the present application;

[0023] Figure 3 A schematic view of the elastic member when it extends into the exhaust hole of the embodiment of the present application;

[0024] Figure 4 A schematic view of the elastic member when it extends into the exhaust hole of the embodiment of the present application; Figure 3 An enlarged view of the detail at A in the embodiment of the present application;

[0025] Figure 5 A schematic view of the coating of the embodiment of the present application;

[0026] Figure 6 A schematic view of the oil storage groove of the embodiment of the present application;

[0027] Figure 7 A comparison curve of thermal expansion deformation of the piston of SiC ceramic material and the conventional material piston;

[0028] Figure 8 An unbalanced excitation force distribution diagram of the piston with different balance weights;

[0029] Figure 9 A noise verification curve diagram of the piston of SiC ceramic material and the conventional material piston.

[0030] FIG. 1 is a cylinder seat; 2 is a cylinder hole; 201 is a coating; 3 is a valve plate assembly; 301 is an exhaust hole; 302 is a valve plate; 4 is a piston; 401 is a first end face; 5 is a piston pin; 501 is a pin shaft hole; 502 is an oil storage groove; 6 is a connecting rod; 7 is an elastic member; 8 is a crankshaft. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and in the absence of the opposite description, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0033] For purposes of the description hereinafter, spatial relative terms, such as "above", "below", "upper", "lower", and the like, can be used to describe the relative position of one element or feature to another element or feature as illustrated in the figures. It will be understood that the spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "up" other elements or features would then be oriented "below" or "down" the other elements or features. Thus, the exemplary term "above" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0034] In addition, it should be noted that the use of "first", "second", and the like words of distinction do not connote any meaning of importance, but are used only to distinguish one element from another, and are used subject to change only the context. Consequently, the use of such terms is not intended to limit the scope of the present application to the specific embodiments presented herein. Nor, therefore, should these terms be taken to exclude the device from claiming usage in

[0035] With reference to the drawings Figures 1 to 4 As shown, according to the embodiment of the present application, a pump body assembly is provided, which comprises a cylinder seat 1, a piston 4 and a valve plate assembly 3; the cylinder seat 1 is provided with a cylinder hole 2; the valve plate assembly 3 is connected with the cylinder seat 1, and the valve plate assembly 3 is provided with an exhaust hole 301, which is communicated with the cylinder hole 2; the valve plate assembly 3 comprises a valve piece 302, which covers the exhaust hole 301; the piston 4 is provided with a first end surface 401 facing the exhaust hole 301, and the first end surface 401 is provided with an elastic member 7; the piston 4 is movably arranged in the cylinder hole 2, so that the elastic member 7 extends into or away from the exhaust hole 301

[0036] It is worth mentioning that in the present embodiment, when the elastic member 7 extends into the exhaust hole 301, the elastic member 7 also abuts against the valve piece 302.

[0037] Specifically, the piston 4 reciprocates in the cylinder bore 2, when the first end face 401 gradually approaches the exhaust hole 301, the gas in the cylinder bore 2 is compressed, at the same time, the elastic member 7 gradually moves to the exhaust hole 301, the elastic member 7 is in the elongated state, when the piston 4 moves to the position, the piston 4 runs to the top dead center position, the compressor starts the exhaust process, at this time, the elastic member 7 extends into the exhaust hole 301, the elastic member 7 abuts against the valve plate 302, the elastic member 7 is in the compressed state, the valve plate 302 is opened, the valve plate 302 no longer covers the exhaust hole 301, both ends of the exhaust hole 301 are open, so as to exhaust the compressed gas in the cylinder bore 2; when the exhaust is finished and the suction starts, the first end face 401 gradually moves away from the exhaust hole 301, the elastic member 7 extends from the exhaust hole 301 and gradually moves away from the valve plate 302, the elastic force of the elastic member 7 is recovered, and the valve plate 302 covers the exhaust hole 301 again.

[0038] In the embodiment, the elastic member 7 is arranged on the first end face 401 of the piston 4, compared with the valve plate 302 being bent only by the exhaust pressure, the elastic member 7 arranged in the embodiment is equivalent to providing an external force to the valve plate 302, pushing the valve plate 302 to open, improving the opening force of the valve plate 302, making the exhaust opening more timely, after the exhaust is finished, the valve plate 302 is closed in time under the action of the elastic force of the elastic member 7, improving the backflow and the delayed closing problem of the exhaust hole 301, and improving the working efficiency of the valve plate 302 assembly. Moreover, the movement process of the elastic member 7 is related to the reciprocating movement of the piston 4, fully combining the movement law of the piston 4, without arranging additional movement components to drive the elastic member 7 to move.

[0039] Referring to Figures 1 to 4 It is shown that the piston 4 is made of ceramic material.

[0040] Specifically, the direction shown in Figure 1 When the compressor exhausts, the piston 4 moves to the left, when the compressor exhausts and starts to suck, the piston 4 moves away from the exhaust hole 301, that is, moves to the right, and the piston 4 reciprocates in the cylinder bore 2. In the embodiment, the piston 4 reciprocates, the ceramic material has the characteristics of light weight, the piston 4 is made of ceramic material, the overall weight of the piston 4 is reduced, the unbalanced inertia force caused by the high-frequency piston 4 impact is effectively reduced, and the noise level of the whole machine is reduced.

[0041] Referring to Figures 1 to 4 It is shown that the gap between the piston 4 and the cylinder bore 2 is 4-6um.

[0042] In the embodiment, the piston 4 is made of ceramic material, the gap between the piston 4 and the cylinder bore 2 is 4-6 um, and the fitting gap between the outer diameter of the conventional powder metallurgy material piston 4 and the hole of the cylinder seat 1 is 6-10 um. Since the piston 4 is made of ceramic material, the thermal expansion coefficient is lower, and the high-temperature thermal expansion coefficient of the piston 4 is reduced by 45%. In order to reduce the leakage and the clearance volume, the fitting gap between the piston 4 and the cylinder bore 2 is set to 4-6 um, so as to ensure the lubricating oil flow and the sufficient sealing, reduce the clearance volume between the piston 4 and the cylinder bore 2, maximize the lubricating oil flow and the sealing, improve the wear problem of the piston 4 and the cylinder bore 2, and improve the reliability of the compressor.

[0043] Referring to Figures 1 to 5 As shown in the figure, the piston 4 is movably arranged along the axis of the cylinder bore 2, the cylinder bore 2 is provided with a coating 201, and the radial outer edge of the piston 4 has a gap with the coating 201, and the coating 201 has the same thermal expansion coefficient as the piston 4.

[0044] Specifically, when the piston 4 performs exhaust movement, the first end surface 401 of the piston 4 gradually approaches the exhaust hole 301, the compressor exhaust is completed, and the suction is started. The piston 4 moves away from the exhaust hole 301, so that the piston 4 contacts the inner wall of the cylinder bore 2 during reciprocating movement, and friction is generated between the two. In the embodiment, the inner wall of the cylinder bore 2 is provided with a wear-resistant and high-temperature-resistant coating 201, and the coating 201 has the same thermal expansion coefficient as the piston 4. It is ensured that the piston 4 and the cylinder bore 2 have the same deformation under high-frequency operation of the compressor, so as to ensure that the gap between the piston 4 and the cylinder bore 2 does not increase or decrease due to thermal deformation, thereby improving the wear resistance of the cylinder bore 2 and the piston 4. In other embodiments, the material of the coating 201 ensures that the piston 4 has the same or similar material hardness and expansion coefficient.

[0045] As a specific embodiment, the coating 201 is a DLC coating 201, and the thickness of the coating 201 is 0.01-0.02 mm. The diamond-like carbon film (DLC film) is a metastable material combined in the form of sp3 and sp2 bonds, which has excellent properties of diamond and graphite, high hardness, high resistivity, good optical performance, and excellent tribological properties.

[0046] Referring to Figures 1 to 6 As shown in the figure, the pump body assembly further includes a piston pin 5 and a connecting rod 6. The connecting rod 6 and the piston 4 have a pin shaft hole 501, and the piston pin 5 is arranged in the pin shaft hole 501 to connect the connecting rod 6 and the piston 4. An oil storage groove 502 is formed in the outer wall of the piston pin 5 or the inner wall of the pin shaft hole 501.

[0047] Specifically, one end of the connecting rod 6 is connected with the eccentric wheel of the crankshaft 8, the crankshaft 8 is driven to rotate by the motor, one end of the connecting rod 6 is connected with the eccentric wheel of the crankshaft 8, and the other end is connected with the piston 4. When the crankshaft 8 rotates, the movement of the eccentric wheel makes the connecting rod 6 move, causing the connecting rod 6 to swing, thereby driving the piston 4 to reciprocate.

[0048] In this embodiment, since the connecting rod 6 and the piston 4 are connected through the piston pin 5, when the compressor is operated at high frequency, friction will occur between the piston pin 5 and the pin hole 501 of the connecting rod 6, which is easy to cause wear of the piston pin 5 and the connecting rod 6. The oil storage groove 502 is arranged on the outer wall of the piston pin 5 or the inner wall of the pin hole 501, which can improve the lubrication effect of the piston pin 5 and the connecting rod 6 and improve the wear problem of the piston pin 5 and the connecting rod 6.

[0049] For reference Figures 1 to 6 As shown in the figure, the oil storage groove 502 is arranged on the inner wall of the pin hole 501 of the piston 4, and the oil storage groove 502 is in a spiral shape.

[0050] In this embodiment, the oil storage groove 502 can be arranged on the outer wall of the piston pin 5 or the inner wall of the pin hole 501 of the piston 4. The crankshaft 8 of the compressor rotates to drive the piston 4 to reciprocate, the crankshaft 8 is provided with an oil supply groove, the lubricating oil flows upward from the bottom wall of the crankshaft 8, the lubricating oil is thrown out of the oil supply groove, part of the lubricating oil is thrown onto the piston pin 5, and the lubricating oil flows into the oil storage groove 502. The lubricating oil flowing into the oil storage groove 502 plays a lubricating role between the piston pin 5 and the connecting rod 6, and since the oil storage groove 502 is in a spiral shape, the flow path of the lubricating oil is increased, the oil storage groove 502 plays a role of storing lubricating oil, thereby improving the lubrication effect between the piston pin 5 and the connecting rod 6 and avoiding dry friction between the two.

[0051] For reference Figures 1 to 4 As shown in the figure, the piston pin 5 is made of ceramic material, or the piston pin 5 and the piston 4 are both made of ceramic material.

[0052] Specifically, when the crankshaft 8 rotates, the movement of the eccentric wheel makes the connecting rod 6 move, causing the connecting rod 6 to swing, thereby driving the piston 4 to reciprocate. When the piston 4 performs the exhaust process, the first end surface 401 of the piston 4 and the elastic member 7 gradually approach the exhaust hole 301. In the process of continuous exhaust, the elastic member 7 will enter the exhaust hole 301, and the valve plate 302 will open more timely. When the compressor exhausts, the piston 4 will move away from the exhaust hole 301, and under the action of the elastic member 7, the exhaust valve plate 302 will be closed in time.

[0053] In the embodiment, the piston pin 5 is made of ceramic material, the mass of the piston pin 5 is reduced, the ceramic material has the characteristic of high thermal conductivity, the heat of the cylinder head can be accelerated, the temperature of the movement core is reduced, and the performance level of the whole machine is improved. The inner wall of the pin shaft hole 501 of the piston 4 is further provided with an oil storage groove 502, and the material characteristics can further reduce the friction between the piston pin 5 and the connecting rod 6.

[0054] In the embodiment, the rotating motion of the crankshaft 8 of the compressor drives the piston 4 to make reciprocating motion through the connecting rod 6. The piston 4 and the piston pin 5 have reciprocating inertia force and rotating inertia force during the reciprocating motion, and the size of the reciprocating inertia force and the rotating inertia force periodically changes with the crankshaft 8 rotation angle during the rotation of the compressor. The generation of the inertia force will cause the compressor to vibrate, and the vibration needs to be balanced and eliminated by external design. The rotating inertia force can be completely balanced, while the reciprocating inertia force includes first-order reciprocating inertia force and second-order reciprocating inertia force, and only part of the first-order reciprocating inertia force can be balanced. The rotating inertia force is related to the rotating mass, and the reciprocating inertia force is related to the reciprocating mass. The reciprocating inertia force generated by the reciprocating motion of the piston 4 and the piston pin 5 is greatly affected by the mass. The piston 4 and the piston pin 5 in the embodiment are made of ceramic material, have the characteristic of light mass, and the reciprocating inertia force generated by the piston 4 and the piston pin 5 is also much lower. Therefore, the reciprocating inertia force caused by the unbalance can be reduced.

[0055] The material composition of the ceramic material is AlSiC. The raw material of the ceramic material includes SiC and Al in mass percentage, the mass percentage of SiC is greater than 70%, and Al is a sintering aid.

[0056] In the embodiment, a small amount of Al is added as a sintering aid, and the mass percentage of SiC is greater than 70% in mass percentage. The piston 4 made of AlSiC material has Mohs hardness of 9.2-9.5 and microhardness of 33400MPa, which is only second to diamond, and has the characteristic of high thermal conductivity, so that the heat of the cylinder head can be accelerated, the temperature of the movement core is reduced, and the performance of the whole machine is improved. Moreover, the overall mass of the piston 4 is reduced, the mass of the piston 4 is reduced by 54%, the reciprocating inertia force is reduced by 45%, the unbalanced inertia force caused by the high-frequency impact of the piston 4 is effectively reduced, and the noise level of the whole machine is reduced.

[0057] As a specific embodiment, when the piston 4 and the piston pin 5 are both made of ceramic material, the material characteristics make the piston 4 mass reduce by 54% than conventional powder metallurgy material, the reciprocating inertia force caused by the unbalance of the piston 4 reduces by 45%, effectively reducing the unbalanced inertia force caused by the impact of the piston 4 in high frequency operation, and the overall machine noise is reduced by 2-5 dB. In addition, the piston 4 has the characteristics of high thermal conductivity, which can accelerate the heat dissipation of the cylinder head, reduce the temperature of the movement, and improve the performance level of the whole machine. The high temperature thermal expansion coefficient of the piston 4 is reduced by 45% than the conventional powder metallurgy material piston 4, and the piston 4 and the cylinder hole 2 are optimized. The clearance setting is 4-6um, which reduces the clearance volume of the piston 4 and the cylinder hole 2, maximizes the lubricating oil flow and sealing, improves the wear problem of the piston 4 and the cylinder hole 2, and improves the reliability of the compressor.

[0058] For reference Figures 1 to 4 As shown in the figure, the elastic member 7 is a spring, and the elastic member 7 is arranged on the axis of the exhaust hole 301, and in the radial direction of the exhaust hole 301, the diameter of the elastic member 7 is smaller than the diameter of the exhaust hole 301.

[0059] In this embodiment, since the elastic member 7 is arranged on the first end surface 401 of the piston 4, in order to make the elastic member 7 smoothly abut against the valve plate 302 after extending into the exhaust hole 301, the elastic member 7 is arranged on the axis of the exhaust hole 301, and the axis of the exhaust hole 301 is a straight line in the horizontal direction, so that when the piston 4 moves to the position, the elastic member 7 abuts against the valve plate 302, and the valve plate 302 is more easily opened. In view of the fact that the piston 4 moves in the opposite direction when the compressor inhales, the elastic member 7 extends out of the exhaust hole 301, and the diameter of the elastic member 7 is smaller than the diameter of the exhaust hole 301, and even when the elastic member 7 extends into the exhaust hole 301, the elastic member 7 will not affect normal exhaust.

[0060] A compressor comprising a pump body assembly, the pump body assembly being the pump body assembly described above.

[0061] For reference Figures 7 to 9As shown, in the present embodiment, the elastic member 7 is arranged on the first end surface 401 of the piston 4, and after the elastic member 7 extends into the exhaust hole 301, the elastic member 7 abuts against the valve piece 302 to provide a certain opening force to the valve piece 302. When the piston 4 moves reversely, the elastic member 7 provides a certain elastic force to make the valve piece 302 more easily close the exhaust hole 301. Moreover, according to the movement characteristics of the piston 4 and the piston pin 5, both the piston 4 and the piston pin 5 are made of ceramic material, and the material characteristics of the ceramic material make the mass of the piston 4 reduce by 54% than conventional powder metallurgy material, and the unbalanced reciprocating inertia force of the piston 4 reduces by 45%, effectively reducing the unbalanced inertia force caused by the impact of the piston 4 in high-frequency operation, and reducing the overall noise of the machine by 2-5 dB. In addition, the piston 4 has the characteristics of high thermal conductivity, which can accelerate the heat dissipation of the cylinder head, reduce the temperature of the movement, and improve the performance level of the whole machine. Moreover, the high-temperature thermal expansion coefficient of the piston 4 is reduced by 45% than conventional powder metallurgy material, and the piston 4 optimizes the fit clearance between the piston 4 and the cylinder hole 2 to be set at 4-6 um, reduces the clearance volume between the piston 4 and the cylinder hole 2, maximizes the lubricating oil flow and sealing performance, improves the wear problem between the piston 4 and the cylinder hole 2, and improves the reliability of the compressor.

[0062] Those skilled in the art will readily understand that the above-mentioned advantageous modes can be freely combined and superimposed without conflict.

[0063] The above is only the preferred embodiment of the present application, and should not be used to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above is only the preferred embodiment of the present application, and should not be used to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A pump body assembly, characterized by, The pump body assembly comprises: a cylinder base (1), a piston (4) and a valve plate assembly (3); a cylinder hole (2) is formed in the cylinder base (1); the valve plate assembly (3) is connected with the cylinder base (1), an exhaust hole (301) is formed in the valve plate assembly (3), the exhaust hole (301) is communicated with the cylinder hole (2); the valve plate assembly (3) comprises a valve piece (302), the valve piece (302) covers the exhaust hole (301); the piston (4) has a first end face (401) facing the exhaust hole (301), an elastic member (7) is arranged on the first end face (401), the piston (4) is arranged in the cylinder hole (2) in a reciprocating manner, so that the elastic member (7) extends into the exhaust hole (301) or is away from the exhaust hole (301); when the elastic member (7) extends into the exhaust hole (301), the elastic member (7) abuts against the valve piece (302), and the elastic member (7) is in a compressed state.

2. The pump body assembly of claim 1, wherein, The piston (4) is made of ceramic material.

3. The pump body assembly of claim 2, wherein, The gap between the piston (4) and the cylinder hole (2) is 4-6 um.

4. The pump body assembly of claim 1, wherein, The piston (4) is movably arranged along the axis of the cylinder hole (2), a coating layer (201) is arranged on the cylinder hole (2), there is a gap between the radial outer edge of the piston (4) and the coating layer (201), and the thermal expansion coefficient of the coating layer (201) is the same as that of the piston (4).

5. The pump body assembly of any one of claims 1 to 4, wherein, The pump body assembly further comprises a piston pin (5) and a connecting rod (6), the connecting rod (6) and the piston (4) have a pin shaft hole (501), the piston pin (5) is arranged in the pin shaft hole (501), so that the connecting rod (6) is connected with the piston (4); an oil storage groove (502) is formed in the outer wall of the piston pin (5) or the inner wall of the pin shaft hole (501).

6. The pump body assembly of claim 5, wherein, The oil storage groove (502) is formed in the inner wall of the pin shaft hole (501) of the piston (4), and the oil storage groove (502) is in a spiral shape.

7. The pump body assembly of claim 5, wherein, The piston pin (5) is made of ceramic material, or both the piston pin (5) and the piston (4) are made of ceramic material.

8. The pump body assembly of claim 1, wherein, The elastic member (7) is a spring, the elastic member (7) is arranged on the axis of the exhaust hole (301), and in the radial direction of the exhaust hole (301), the diameter of the elastic member (7) is smaller than the diameter of the exhaust hole (301).

9. The pump body assembly of claim 2, wherein, The material composition of the ceramic material is AlSiC, wherein, in terms of mass percentage, the raw material of the ceramic material comprises SiC and Al, the mass percentage of SiC is greater than 70%, and Al is a sintering aid.

10. A compressor comprising a pump body assembly, characterized by, The pump body assembly is any one of claims 1-9.

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