CN217976490U

CN217976490U - Air compressor

Info

Publication number: CN217976490U
Application number: CN202222516564.3U
Authority: CN
Inventors: 王东; 舒向东
Original assignee: Sichuan Danfu Environmental Technology Co ltd
Current assignee: Sichuan Danfu Environmental Technology Co ltd
Priority date: 2022-09-22
Filing date: 2022-09-22
Publication date: 2022-12-06
Anticipated expiration: 2032-09-22

Abstract

The utility model discloses an air compressor relates to air compressor technical field, and mainly used solves traditional multistage air compression equipment and has the problem that air compression is efficient, the energy consumption is high. The main structure is as follows: the piston mounting cylinder is characterized by comprising a piston mounting cylinder, wherein two ends of the piston mounting cylinder are respectively connected with an air inlet cylinder cover and an air exhaust cylinder cover; an air inlet channel and an output flow channel are arranged in the air inlet cylinder cover, and an exhaust channel and an input flow channel are arranged in the exhaust cylinder cover; a communicating flow channel with two ends respectively communicated with the air outlet end of the output flow channel and the air inlet end of the input flow channel is arranged in the side wall of the piston mounting cylinder; the air inlet end of the air inlet channel, the air inlet end of the output flow channel, the air outlet end of the input flow channel and the air inlet end of the exhaust channel are all provided with one-way valves. The utility model provides a pair of air compressor, this air compressor can improve air compression efficiency to reach the purpose that reduces the energy consumption.

Description

Air compressor

Technical Field

The utility model relates to an air compressor technical field especially relates to an air compressor.

Background

At present, with the market demand, the application of the multi-stage air compressor is more and more extensive. The existing multistage air compressor generally communicates a plurality of independently arranged compression cavities through a straight-through communication pipeline, and finally achieves the required pressure by pressurizing air step by step, namely natural air is firstly sucked into a first-stage compression cavity, the air is compressed to the interstage pressure by a first piston in the first-stage compression cavity, and then the part of compressed air is sent into a second-stage compression cavity through a pipeline, secondary compression is carried out by a second piston, and the like until the air is compressed to the final exhaust pressure, so that the whole compression process is completed.

However, in the operation of the conventional multi-stage air compressor, when the air in the compression chamber is compressed, a part of the air flows into the communication pipeline, so that the compression chamber cannot compress the air to a preset compression ratio. Therefore, the traditional multistage air compression equipment always has the problems of low air compression efficiency and high energy consumption, and further the working efficiency of the air compression equipment is low.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an air compressor, this air compressor can improve air compression efficiency to reach the purpose that reduces the energy consumption.

In order to achieve the purpose, the utility model provides an air compressor, which comprises a piston installation cylinder, wherein the two ends of the piston installation cylinder are respectively connected with an air inlet cylinder cover and an air exhaust cylinder cover, the inner diameter of the air inlet side of the piston installation cylinder is larger than that of the air outlet side of the piston installation cylinder, a piston capable of reciprocating along the air flow direction is arranged in the piston installation cylinder, and the two ends of the piston are respectively provided with a first piston body and a second piston body which are in sliding sealing fit with the inner wall of the piston installation cylinder;

the exhaust cylinder cover is internally provided with an exhaust channel of which the air inlet end is communicated with the inner cavity of the piston mounting cylinder and an input channel of which the air outlet end is communicated with the inner cavity of the piston mounting cylinder; a communicating flow channel with two ends respectively communicated with the air outlet end of the output flow channel and the air inlet end of the input flow channel is arranged in the side wall of the piston mounting cylinder; and the air inlet end of the air inlet channel, the air inlet end of the output flow channel, the air outlet end of the input flow channel and the air inlet end of the exhaust channel are all provided with one-way valves which can be opened along the air flow direction.

As a further improvement, a motor interface is arranged on the side wall of one side of the piston installation cylinder, and a motor for driving the piston to move back and forth is arranged on the motor interface.

As a further improvement of the present invention, the motor includes a motor stator housing and a motor rotor coaxially disposed in the motor stator housing, one end of the motor stator housing is connected to the motor interface, the other end is connected to the motor rear end cover, one end of the motor rotor is rotatably connected to the motor rear end cover, and the other end is rotatably mounted in the motor interface through a mounting bearing;

and an eccentric shaft which is eccentrically arranged is arranged on the end face of a motor rotor arranged in the motor interface, and the eccentric shaft is in transmission connection with the piston through a transmission block.

As a further improvement, the extending direction of the motor rotor and the eccentric shaft is perpendicular to the moving direction of the piston, and the piston is further provided with a transmission shaft pin perpendicular to the moving direction of the piston, the upper portion and the lower portion of the transmission block are respectively provided with an eccentric shaft jack and a transmission shaft pin jack for inserting the eccentric shaft and the transmission shaft pin in a rotary manner.

As a further improvement, the exhaust cylinder cover is further provided with a dryer, and the air outlet end of the exhaust channel is communicated with the air inlet end of the dryer.

As a further improvement of the present invention, a sealing ring is disposed on the outer wall of the first piston body and surrounds the axis of the first piston body, and a piston guide ring is disposed on the outer wall of the first piston body near one side of the second piston body and surrounds the axis of the first piston body.

As a further improvement of the present invention, a sealing top ring disposed around the axis of the first piston body is further disposed between the sealing ring and the outer wall of the first piston body.

As a further improvement of the present invention, a sealing ring is disposed on the outer wall of the second piston body and surrounds the axis of the second piston body, and a piston guide ring is disposed on the outer wall of the second piston body, which is close to the first piston body, and surrounds the axis of the first piston body.

As a further improvement of the present invention, a sealing top ring disposed around the axis of the second piston body is further disposed between the sealing ring and the outer wall of the second piston body.

As a further improvement, the check valve comprises a valve plate and a valve plate which are arranged in an overlapping manner, and the surfaces of the valve plate and the valve plate are perpendicular to the air flow direction.

Compared with the prior art, the utility model discloses an air compressor's advantage does:

1. along with the reciprocating movement of the piston, air is firstly sucked into the air inlet side of the piston mounting cylinder from the air inlet channel, then is compressed by the first piston body, and then the air after primary compression is sent to the air outlet side of the piston mounting cylinder through the output flow channel, the communication flow channel and the input flow channel, is subjected to secondary compression of the second piston body along with the resetting of the piston and is sent to the exhaust channel, so that the whole air compression process is completed.

In the device, because the inner diameter of the air inlet side of the piston mounting cylinder is larger than the inner diameter of the air outlet side of the piston mounting cylinder, secondary pressurization and compression of air can be completed in two compression processes, and a higher compression ratio is achieved. The one-way valves arranged at the air outlet end of the air inlet channel can prevent air from flowing back to the air inlet channel under the compression of the first piston body, and the one-way valves arranged at the air inlet end of the output flow channel and the air outlet end of the input flow channel can ensure that air can enter the air outlet side of the piston installation cylinder through the output flow channel, the communication flow channel and the input flow channel and can not flow back after reaching preset pressure under the compression of the first piston body. Meanwhile, the check valve arranged at the air outlet end of the input flow channel can prevent air from flowing back to the communicating flow channel under the compression of the second piston body, and the check valve arranged at the air inlet end of the exhaust channel can ensure that the air can enter the exhaust channel after reaching a preset pressure under the compression of the second piston body. Compare in current air compression equipment, this air compressor so designs, can guarantee that the air can both reach predetermined pressure promotion in twice compression process to can guarantee whole air compressor's air compression ratio, and then can improve air compression efficiency, thereby reach the purpose that reduces the energy consumption.

2. The secondary air compressor can continuously perform air suction, primary compression, secondary compression and exhaust by utilizing the reciprocating movement of the piston and matching the first piston body and the second piston body at the two ends of the piston. Compared with the existing multistage air compressor, the air compressor can smoothly and continuously complete secondary compression of air by only driving one piston, the number of parts is reduced, and the structure is simplified.

3. The eccentric shaft can be driven to eccentrically rotate by the rotation of a motor rotor in the motor, and then the piston is driven to reciprocate by the linkage of the transmission block and the transmission pin shaft. The driving structure can stably and continuously drive the piston in a reciprocating mode, and the normal operation of the whole secondary air machine compressor is guaranteed.

4. The sealing rings arranged on the outer walls of the first piston body and the second piston body can ensure sliding sealing fit between the first piston body and the inner wall of the piston mounting cylinder, so that air leakage is avoided, air compression to a preset compression ratio is guaranteed, and compression efficiency is guaranteed. Meanwhile, the piston guide ring can play a role in sliding guide, and the stability of the piston during reciprocating movement can be ensured.

5. The sealing top ring can support the sealing ring, so that the sealing effect between the sealing ring and the inner wall of the piston mounting cylinder is ensured.

The invention will become more apparent from the following description when taken in conjunction with the accompanying drawings which illustrate embodiments of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic sectional view of the present invention;

fig. 2 is a schematic diagram of the explosion structure of the present invention.

Wherein: 1-a piston mounting cylinder; 11-a motor interface; 111-mounting a bearing; 12-a communicating flow channel; 2-a piston; 21-a first piston body; 22-a second piston body; 23-a transmission pin shaft; 231-pin shaft mounting seats; 24-a piston guide ring; 25-a sealing ring; 26-sealing the top ring; 3-row of cylinder heads; 31-an exhaust channel; 32-a dryer; 33-an input flow channel; 4-entering the cylinder head; 41-an intake passage; 42-an output flow channel; 5-a one-way valve; 51-a valve plate; 52-valve plate; 6, a motor; 61-an eccentric shaft; 62-motor stator housing; 63-a motor rotor; 64-motor rear end cap; 7-a transmission block; 71-eccentric shaft jack; 72-drive pin shaft jack.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without making creative efforts belong to the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined or explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the product of the present invention is used, the description is only for convenience of description of the present invention and simplification, but the indication or suggestion that the device or element to be referred must have a specific position, be constructed and operated in a specific position, and therefore, the present invention should not be construed as being limited thereto.

Furthermore, the terms "horizontal", "vertical", "suspended" and the like do not require that the components be absolutely horizontal or suspended, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the embodiments of the present invention, "a plurality" means at least 3.

In the description of the embodiments of the present invention, it should be further noted that unless explicitly stated or limited otherwise, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Embodiments of the present invention will now be described with reference to the accompanying drawings.

Examples

The utility model discloses a concrete implementation mode is shown in fig. 1-2, an air compressor, including both ends be connected with respectively into piston installation section of thick bamboo 1 of cylinder head 4 and row cylinder head 3. The inner diameter of the air inlet side of the piston mounting cylinder 1 is larger than that of the air outlet side of the piston mounting cylinder, and a piston 2 capable of reciprocating along the air flow direction is arranged in the piston mounting cylinder 1. The two ends of the piston 2 are respectively provided with a first piston body 21 and a second piston body 22 which are in sliding sealing fit with the inner wall of the piston mounting cylinder 1. An air inlet channel 41 with an air outlet end communicated with the inner cavity of the piston mounting cylinder 1 is arranged in the air inlet cylinder cover 4, and an output flow channel 42 with an air inlet end communicated with the inner cavity of the piston mounting cylinder 1 is also arranged. The exhaust cylinder cover 3 is provided with an exhaust channel 31 with an air inlet end communicated with the inner cavity of the piston mounting cylinder 1, and is also provided with an input flow channel 33 with an air outlet end communicated with the inner cavity of the piston mounting cylinder 1. A communicating flow passage 12 is arranged in the side wall of the piston mounting cylinder 1, and two ends of the communicating flow passage are respectively communicated with the air outlet end of the output flow passage 42 and the air inlet end of the input flow passage 33. The air outlet end of the air inlet channel 41, the air inlet end of the output flow channel 42, the air outlet end of the input flow channel 33 and the air inlet end of the air outlet channel 31 are all provided with one-way valves 5 which can be opened along the air flow direction. In this embodiment, the exhaust cylinder cover 3 is further provided with a dryer 32, and the air outlet end of the exhaust channel 31 is communicated with the air inlet end of the dryer 32.

As the piston 2 reciprocates, air is first sucked from the air inlet passage 41 to the air inlet side of the piston mounting cylinder 1, then compressed by the first piston body 21, and then, the primarily compressed air is sent to the air outlet side of the piston mounting cylinder 1 via the output flow passage 42, the communication flow passage 12, and the input flow passage 33, and is secondarily compressed by the second piston body 22, which is restored with the piston 2, and sent to the air outlet passage 31, thereby completing the entire air compression process.

Specifically, as shown in fig. 1, when the piston 1 moves from top to bottom, the first piston body 21 starts to compress the air at the air inlet side of the piston mounting cylinder 1, and when the air at the air inlet side of the piston mounting cylinder 1 is compressed to a preset pressure, the check valves 5 at the air inlet end of the output flow passage 42 and the air outlet end of the input flow passage 33 are simultaneously opened, and the air reaches the air outlet side of the piston mounting cylinder 1 through the output flow passage 42, the communication flow passage 12 and the input flow passage 33. At this time, the output flow passage 42, the communication flow passage 12, the input flow passage 33, and the cavity on the air outlet side of the piston mounting tube 1 are filled with compressed air, and primary compression of air is completed. Then, when the piston 2 moves from bottom to top, the check valve 5 at the air inlet end of the output flow passage 42 and the air outlet end of the input flow passage 33 will be closed rapidly under the action of the pressure difference, the second piston body 22 starts to compress the air at the air outlet side of the piston installation cylinder 1, and when the air compression at the air outlet side of the piston installation cylinder 1 leads the preset pressure, the check valve 5 on the exhaust passage 31 is opened, and the high-pressure air is pressed into the dryer 32 through the check valve 5 on the exhaust passage 31 to complete the secondary compression. At the same time, the check valve 5 on the intake passage 41 is also opened, and new gas is again sucked in as the piston 2 moves upward, so that the next cycle of compression is performed. In this process, since the check valves 5 at the gas inlet end of the output flow passage 42 and the gas outlet end of the input flow passage 33 are both in the closed state, when new gas is sucked, the high-pressure gas in the output flow passage 42, the communication flow passage 12 and the input flow passage 33 does not flow back, so that the gas compression efficiency can be greatly improved.

In the device, because the inner diameter of the air inlet side of the piston mounting cylinder 1 is larger than the inner diameter of the air outlet side of the piston mounting cylinder, secondary pressurization and compression of air can be completed in two compression processes, and a higher compression ratio is achieved. The check valve 5 disposed at the outlet end of the inlet channel 41 can prevent air from flowing back into the inlet channel 4 under compression of the first piston body 21, and the check valves 5 disposed at the inlet end of the outlet channel 42 and the outlet end of the inlet channel 33 can ensure that air can enter the outlet side of the piston mounting cylinder 1 through the outlet channel 42, the communication channel 12 and the inlet channel 33 and cannot flow back after reaching a preset pressure under compression of the first piston body 21. Meanwhile, the check valve 5 disposed at the outlet end of the input flow passage 33 can prevent the air from flowing back into the communicating flow passage 12 under the compression of the second piston body 22, and the check valve 5 disposed at the inlet end of the exhaust passage 31 can ensure that the air can enter the exhaust passage 31 only after reaching a preset pressure under the compression of the second piston body 22. Compare in current air compression equipment, this air compressor so designs, can guarantee that the air can both reach predetermined pressure promotion in twice compression process to can guarantee whole air compressor's air compression ratio, and then can improve air compression efficiency, thereby reach the purpose that reduces the energy consumption. In addition, the secondary air compressor can continuously perform air suction, primary compression, secondary compression, and air discharge by the reciprocating movement of the piston 2 in cooperation with the first piston body 21 and the second piston body 22 at both ends of the piston 2. Compare in current multistage air compressor, this air compressor only needs drive a piston 2 can be smooth and the secondary compression of the completion air that lasts, has reduced part quantity, has simplified the structure.

And regarding the driving of the piston 2, a motor interface 11 is arranged on one side wall of the piston mounting cylinder 1, and a motor 6 for driving the piston 2 to reciprocate is arranged on the motor interface 11. Specifically, the motor 6 includes a motor stator housing 62 and a motor rotor 63 coaxially disposed within the motor stator housing 62. One end of the motor stator shell 62 is hermetically connected with the motor interface 11, and the other end is hermetically connected with the motor rear end cover 64. One end of the motor rotor 63 is rotatably connected with the motor rear end cover 64, and the other end is rotatably installed in the motor interface 11 through an installation bearing 111. In this embodiment, an eccentric shaft 61 is eccentrically disposed on an end surface of a motor rotor 63 installed in the motor interface 11, and the eccentric shaft 61 is drivingly connected to the piston 2 through a transmission block 7. Specifically, the extending directions of the motor rotor 63 and the eccentric shaft 61 are both perpendicular to the moving direction of the piston 2, and the piston 2 is further provided with a transmission shaft pin 23 perpendicular to the moving direction of the piston 2. The upper part and the lower part of the transmission block 7 are respectively provided with an eccentric shaft insertion hole 71 and a transmission pin shaft insertion hole 72 for rotatably inserting the eccentric shaft 61 and the transmission pin shaft 23. As shown in fig. 1, a notch is formed in the sidewall of the piston 2 to accommodate the actuator block 7, and a pin mounting seat 231 is formed at the lower portion of the notch to mount the actuator pin 23.

The eccentric shaft 61 can be driven to eccentrically rotate by the rotation of the motor rotor 63 in the motor 6, and then the piston 2 is driven to reciprocate by the linkage of the transmission block 7 and the transmission pin shaft 23. The driving structure can stably and continuously drive the piston 2 in a reciprocating manner, and the normal operation of the whole secondary air compressor is ensured.

Furthermore, a sealing ring 25 is disposed around the axis of the first piston body 21 on the outer wall thereof, and a piston guide ring 24 is disposed around the axis of the first piston body 21 on the outer wall thereof on the side closer to the second piston body 22. The sealing ring 25 arranged on the outer wall of the first piston body 21 can ensure the sliding sealing fit between the first piston body 21 and the inner wall of the piston installation cylinder 1, so that air leakage is avoided, air compression to a preset compression ratio is ensured, and the compression efficiency is ensured. Meanwhile, the piston guide ring 24 can play a role of sliding guide, and can ensure the stability of the piston 2 during reciprocating movement. In this embodiment, a top sealing ring 26 disposed around the axis of the first piston body 21 is further disposed between the sealing ring 25 and the outer wall of the first piston body 21. The sealing top ring 26 can support the sealing ring 25, so that the sealing effect between the sealing ring 25 and the inner wall of the piston mounting cylinder 1 is ensured.

Meanwhile, the outer wall of the second piston body 22 is also provided with a sealing ring 25 arranged around the axis thereof, and the outer wall of the second piston body 22 on the side close to the first piston body 21 is also provided with a piston guide ring 24 arranged around the axis thereof. The sealing ring 25 arranged on the outer wall of the second piston body 22 can ensure the sliding sealing fit between the second piston body 22 and the inner wall of the piston installation cylinder 1, so that air leakage is avoided, air compression to a preset compression ratio is guaranteed, and compression efficiency is guaranteed. Meanwhile, the piston guide ring 24 can play a role of sliding guide, and can ensure the stability of the piston 2 during reciprocating movement. In this embodiment, a top sealing ring 26 disposed around the axis of the second piston body 22 is further disposed between the sealing ring 25 and the outer wall of the second piston body 22. The sealing top ring 26 can support the sealing ring 25, so that the sealing effect between the sealing ring 25 and the inner wall of the piston mounting cylinder 1 is ensured.

In addition, regarding the check valve 5, the check valve 5 in the present embodiment includes a valve plate 51 and a valve plate 52 that are disposed in an overlapping manner. The surfaces of the valve plate 51 and the valve plate 52 are perpendicular to the air flow direction, and can sense the air pressure variation in time and open/close.

The present invention has been described above with reference to the preferred embodiments, but the present invention is not limited to the above-disclosed embodiments, and various modifications, equivalent combinations, which are made according to the essence of the present invention, should be covered.

Claims

1. An air compressor is characterized by comprising a piston mounting cylinder (1) of which two ends are respectively connected with an air inlet cylinder cover (4) and an air outlet cylinder cover (3), wherein the inner diameter of an air inlet side of the piston mounting cylinder (1) is larger than that of an air outlet side of the piston mounting cylinder, a piston (2) capable of reciprocating along the air flow direction is arranged in the piston mounting cylinder (1), and a first piston body (21) and a second piston body (22) which are in sliding sealing fit with the inner wall of the piston mounting cylinder (1) are respectively arranged at two ends of the piston (2);

an air inlet channel (41) with an air outlet end communicated with the inner cavity of the piston mounting cylinder (1) is arranged in the air inlet cylinder cover (4), an output flow channel (42) with an air inlet end communicated with the inner cavity of the piston mounting cylinder (1) is also arranged in the air exhaust cylinder cover (3), an exhaust channel (31) with an air inlet end communicated with the inner cavity of the piston mounting cylinder (1) is also arranged in the air exhaust cylinder cover, and an input flow channel (33) with an air outlet end communicated with the inner cavity of the piston mounting cylinder (1) is also arranged in the air exhaust cylinder cover; a communicating flow channel (12) with two ends respectively communicated with the air outlet end of the output flow channel (42) and the air inlet end of the input flow channel (33) is arranged in the side wall of the piston mounting cylinder (1); and the air outlet end of the air inlet channel (41), the air inlet end of the output flow channel (42), the air outlet end of the input flow channel (33) and the air inlet end of the exhaust channel (31) are respectively provided with a one-way valve (5) which can be opened along the air flow direction.

2. The air compressor according to claim 1, wherein a motor interface (11) is provided on a side wall of the piston mounting cylinder (1), and the motor interface (11) is provided with a motor (6) for driving the piston (2) to reciprocate.

3. The air compressor as claimed in claim 2, wherein the motor (6) comprises a motor stator housing (62) and a motor rotor (63) coaxially arranged in the motor stator housing (62), one end of the motor stator housing (62) is connected with the motor interface (11), the other end is connected with a motor rear end cover (64), one end of the motor rotor (63) is rotatably connected with the motor rear end cover (64), and the other end is rotatably installed in the motor interface (11) through a mounting bearing (111);

an eccentric shaft (61) which is eccentrically arranged is arranged on the end face of a motor rotor (63) arranged in the motor interface (11), and the eccentric shaft (61) is in transmission connection with the piston (2) through a transmission block (7).

4. The air compressor as claimed in claim 3, wherein the motor rotor (63) and the eccentric shaft (61) extend in a direction perpendicular to the moving direction of the piston (2), the piston (2) is further provided with a driving shaft pin (23) perpendicular to the moving direction of the piston (2), and the upper portion and the lower portion of the driving block (7) are respectively provided with an eccentric shaft insertion hole (71) and a driving shaft pin insertion hole (72) for rotatably inserting the eccentric shaft (61) and the driving shaft pin (23).

5. An air compressor according to claim 1, wherein the exhaust cylinder cover (3) is further provided with a drier (32), and the air outlet end of the exhaust channel (31) is communicated with the air inlet end of the drier (32).

6. The air compressor as claimed in claim 1, wherein the outer wall of the first piston body (21) is provided with a sealing ring (25) around its axial center, and the outer wall of the first piston body (21) on the side close to the second piston body (22) is provided with a piston guide ring (24) around its axial center.

7. The air compressor as claimed in claim 6, wherein a top sealing ring (26) is disposed around the axial center of the first piston body (21) between the sealing ring (25) and the outer wall of the first piston body (21).

8. The air compressor as claimed in any one of claims 1, 6 or 7, wherein the outer wall of the second piston body (22) is provided with a sealing ring (25) disposed around the axial center thereof, and the outer wall of the second piston body (22) on the side close to the first piston body (21) is provided with a piston guide ring (24) disposed around the axial center thereof.

9. The air compressor as claimed in claim 8, wherein a top sealing ring (26) is disposed around the axial center of the second piston body (22) between the sealing ring (25) and the outer wall of the second piston body (22).

10. An air compressor according to claim 1, wherein the check valve (5) comprises a valve plate (51) and a valve plate (52) which are arranged in an overlapping manner, and the surfaces of the valve plate (51) and the valve plate (52) are perpendicular to the air flow direction.