Silent air compressor

Abstract

The utility model discloses a mute air compressor, which relates to the field of compressors and comprises a crankcase, a crankshaft is arranged in the crankcase, two first-stage cylinders are arranged on one side of the crankcase, two second-stage cylinders are arranged on the other side of the crankcase, first-stage pistons are arranged in the first-stage cylinders, and first-stage connecting rods are arranged between the first-stage pistons and the crankshaft. A second-stage piston is arranged in the second-stage air cylinder, a second-stage connecting rod is arranged between the second-stage piston and the crankshaft, a motor used for driving the crankshaft to rotate is arranged at one end of the crankcase, a cooler is arranged at the other end of the crankcase, fan blades are arranged on the side, close to the crankcase, of the cooler, and the fan blades are in transmission connection with the crankshaft. A crankshaft cavity is formed in the box body in the length direction in a penetrating mode, first interlayer grooves are symmetrically formed in the two ends of the box body, an end plate is detachably connected to the end, close to the cooler, of the box body, and a middle bracket is installed between the end, close to the motor, of the box body and the motor. The vibration amplitude and noise generated when the compressor works can be greatly reduced.

Description

Technical Field

[0001] The present application relates to the field of compressors, and in particular to a silent air compressor. Background Art

[0002] In order to improve the riding comfort of vehicles, all vehicles are equipped with air-conditioning equipment. At present, no matter it is a family car, commercial bus or high-speed train, the air-conditioning equipment is equipped with a compressor to adjust the temperature inside the car.

[0003] The existing compressor structure includes a crankcase, a crankshaft installed in the crankcase, a piston cylinder arranged on the crankcase, a piston arranged in the piston cylinder, a connecting rod connected between the piston and the crankshaft, and a motor arranged on one side of the crankcase. When in use, the motor drives the crankshaft to rotate, driving the connecting rod to move, and the connecting rod drives the piston to reciprocate in the piston cylinder, thereby compressing the air. The transmission between the crankshaft and the connecting rod is an eccentric transmission, so this transmission method inevitably generates noise and vibration in the crankcase.

[0004] In household cars and commercial buses, the noise requirements for compressors are relatively low. However, for EMUs, the maintenance of EMUs is generally carried out in a unified periodic manner after a certain number of years. During the maintenance period, the EMU is always in service and is generally not maintained. Therefore, the compressors installed on EMUs have strict requirements on noise. Summary of the invention

[0005] In order to optimize the noise of the compressor when it is working, the present application provides a silent air compressor.

[0006] The silent air compressor provided in this application adopts the following technical solution:

[0007] A silent air compressor comprises a crankcase, a crankshaft is arranged in the crankcase, two primary cylinders are arranged on one side of the crankcase, and two secondary cylinders are arranged on the other side, a primary piston is arranged in the primary cylinder, a primary connecting rod is arranged between the primary piston and the crankshaft, a secondary piston is arranged in the secondary cylinder, and a secondary connecting rod is arranged between the secondary piston and the crankshaft, a motor for driving the crankshaft to rotate is arranged at one end of the crankcase, and a cooler for cooling compressed air is arranged at the other end, a fan blade is arranged on a side of the cooler close to the crankcase, and the fan blade is drivingly connected to the crankshaft, the crankcase comprises a case body, a crankshaft cavity is opened through the case body along its length direction, first interlayer grooves are symmetrically opened at both ends of the case body, an end of the case body close to the cooler is detachably connected to an end plate, and an intermediate bracket is installed between the end of the case body close to the motor and the motor.

[0008] By adopting the above technical solution and making the crankcase hollow, the sound insulation and noise reduction performance of the crankcase can be improved.

[0009] Preferably, a first noise reduction plate is fixed to a side of the end plate close to the casing, and a first axial hole for passing the crankshaft is penetrated on the first noise reduction plate; a second noise reduction plate is fixed to a side of the intermediate bracket close to the casing, and a second axial hole for passing the crankshaft is penetrated on the second noise reduction plate.

[0010] By adopting the above technical solution, a sandwich space is formed between the first noise reduction plate and the end plate, and a sandwich space is also formed between the second noise reduction plate and the middle bracket. If the noise in the crankcase is transmitted outward through the two ends of the crankcase, it needs to pass through the sandwich space. The sandwich space has good sound insulation function, so it can greatly prevent the noise in the crankcase from being transmitted out through the ends of the crankcase.

[0011] Preferably, the crankshaft is connected to the first noise reduction plate bearing, a first end seal is fixed to the side of the first noise reduction plate away from the casing, the first end seal sleeve is arranged on the crankshaft, a sandwich guide plate is fixed to the side of the end plate away from the casing, the end of the crankshaft passes through the sandwich guide plate, a second end seal is fixed on the sandwich guide plate, and the second end seal sleeve is arranged on the crankshaft.

[0012] By adopting the above technical scheme, the functions of the first end seal and the second end seal are to prevent external dust or water from entering the crankcase, and at the same time reduce the transmission of noise in the crankcase to the outside. A sandwich space is formed between the first noise reduction plate and the end plate, and a sandwich space is also formed between the second noise reduction plate and the middle bracket. If the noise in the crankcase is transmitted outward through the two ends of the crankcase, it needs to pass through the sandwich space, and the sandwich space has good sound insulation function, so it can greatly prevent the noise in the crankcase from being transmitted through the end of the crankcase; a sandwich space is formed between the sandwich guide plate and the end plate, which further improves the sound insulation and noise reduction performance.

[0013] Preferably, the first-stage piston is an internally aspirated piston, a coupling is connected between the motor output shaft and the crankshaft, the coupling is located in the intermediate bracket, a support plate is fixed to the side of the intermediate bracket close to the housing, a third axial hole is penetrated through the support plate, the end of the crankshaft is penetrated through the third axial hole, a plurality of connecting holes connected to the housing are formed on the side around the second axial hole of the support plate, an air supply hole connected to the connecting hole is formed on the side wall of the intermediate bracket, and an air filter is connected to the air supply hole.

[0014] By adopting the above technical solution, during use, the first-stage piston draws air from the crankcase, thereby accelerating the air flow in the crankcase, which is beneficial to reducing the temperature in the crankcase. At the same time, the outside air enters the middle bracket through the air filter and then enters the crankcase, so the middle bracket is also cooled.

[0015] Preferably, a second interlayer groove is formed at one end of the intermediate bracket.

[0016] By adopting the above technical solution, the sound insulation and noise reduction performance of the middle bracket is improved.

[0017] Preferably, the first-stage cylinder includes a first-stage cylinder body detachably mounted on the box body, an air outlet valve assembly is provided at an opening at one end of the first-stage cylinder body away from the box body, a first-stage valve cover is installed at a side of the air outlet valve assembly away from the cylinder body, a third interlayer groove is provided at a side of the first-stage valve cover away from the first-stage cylinder body, and a first-stage groove cover for closing the third interlayer groove is detachably mounted at a side of the first-stage valve cover away from the first-stage cylinder body.

[0018] By adopting the above technical solution, the sound insulation and noise reduction performance of the first-stage valve cover is improved, and the noise generated during the operation of the first-stage cylinder is prevented from being transmitted outward.

[0019] Preferably, the secondary cylinder is a secondary cylinder body detachably mounted on the box body, a ventilation valve assembly is provided at an opening at one end of the secondary cylinder body away from the box body, a secondary valve cover is installed on a side of the ventilation valve assembly away from the secondary cylinder body, a fourth interlayer groove is provided on a side of the secondary valve cover away from the secondary cylinder body, and a secondary groove cover for closing the fourth interlayer groove is detachably mounted on the side of the secondary valve cover away from the secondary cylinder body.

[0020] By adopting the above technical solution, the sound insulation and noise reduction performance of the secondary valve cover is improved, and the noise during the operation of the secondary cylinder is prevented from being transmitted outward.

[0021] Preferably, the cooler is a combined cooler, the exhaust ports of the two primary cylinders are connected to a primary air duct, the primary air duct is connected to the first air inlet of the cooler, the first air outlet of the cooler is connected to a primary air supply pipe, the primary air supply pipe is connected to the air intake ports of the two secondary cylinders, the exhaust ports of the two secondary cylinders are connected to a secondary air duct, the secondary air duct is connected to the second air inlet of the cooler, and the second air outlet of the cooler is connected to a secondary air supply pipe.

[0022] By adopting the above technical solution, the use of a combined cooler can improve the compactness of the equipment. Secondly, the air compressed twice is cooled by the cooler, which greatly reduces the temperature of the secondary compressed air.

[0023] Preferably, the primary air guide tube, the primary air supply tube, the secondary air guide tube and the air supply tube are all configured as hollow sandwich tubes.

[0024] By adopting the above technical solution, the noise generated by the compressed air being transported in the pipeline is reduced from being transmitted to the outside.

[0025] Preferably, shock-absorbing pads are installed at the bottom of the motor and the crankcase, and mounting fixing plates are installed at the top of the motor and the crankcase.

[0026] By adopting the above technical solution, the vibration transmission of the compressor is reduced.

[0027] In summary, the present application includes at least one of the following beneficial technical effects:

[0028] 1. The present application designs the housing, the first-stage valve cover, the second-stage valve cover and the intermediate bracket to be hollow interlayers, which is beneficial to reduce the transmission of the compressor working noise to the outside, thereby improving the noise and vibration impact of the compressor working noise on the surrounding devices;

[0029] 2. With the help of the interlayer space formed between the first noise reduction plate and the end plate, and the interlayer space also formed between the second noise reduction plate and the middle bracket, if the noise in the crankcase is transmitted outward through the two ends of the crankcase, it needs to pass through the interlayer space, and the interlayer space has a good sound insulation function, so it can greatly prevent the noise in the crankcase from being transmitted out through the ends of the crankcase;

[0030] 3. A sandwich space is formed between the sandwich guide plate and the end plate to further improve the performance of sound insulation and noise reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The overall structure of a silent air compressor according to the present application is shown in FIG. Figure 1 ;

[0032] Figure 2 The overall structure of a silent air compressor according to the embodiment of the present application is shown in FIG. Figure 2 ;

[0033] Figure 3 A cross-sectional view of a silent air compressor in a horizontal direction according to an embodiment of the present application;

[0034] Figure 4 for Figure 3 A partial enlarged view of the middle A part;

[0035] Figure 5 A vertical cross-sectional view of a silent air compressor according to an embodiment of the present application;

[0036] Figure 6 This is a schematic diagram of the overall structure of the box body according to the embodiment of the present application;

[0037] Figure 7 This is a schematic diagram of the overall structure of the middle bracket in the embodiment of the present application;

[0038] Figure 8 This is a schematic diagram of the overall structure of the first-level valve cover and the first-level tank cover of the embodiment of the present application;

[0039] Fig. 9 This is a schematic diagram of the overall structure of the secondary valve cover and the secondary tank cover of the embodiment of the present application;

[0040] Figure numerals: 1, crankshaft; 2, primary cylinder; 3, secondary cylinder; 4, primary piston; 5, primary connecting rod; 6, secondary piston; 7, secondary connecting rod; 8, motor; 9, cooler; 10, fan blade; 11, housing; 12, crankshaft cavity; 13, first interlayer groove; 14, end plate; 15, intermediate bracket; 16, first noise reduction plate; 17, first shaft hole; 18, second noise reduction plate; 19, second shaft hole; 20, first end seal; 21, interlayer guide plate; 22, second end seal; 23, coupling; 24, bracket; 25. The third axial hole; 26. The connecting hole; 27. The air supply hole; 28. The air filter; 29. ​​The second interlayer groove; 30. The first-level cylinder body; 31. The exhaust valve assembly; 32. The first-level valve cover; 33. The third interlayer groove; 34. The first-level groove cover; 35. The second-level cylinder body; 36. The ventilation valve assembly; 37. The second-level valve cover; 38. The fourth interlayer groove; 39. The second-level groove cover; 40. The first-level air guide pipe; 41. The first-level air supply pipe; 42. The second-level air guide pipe; 43. The second-level air supply pipe; 44. The shock-absorbing pad; 45. The mounting plate. DETAILED DESCRIPTION

[0041] The following is combined with Figure 1-9 This application is described in further detail.

[0042] The embodiment of the present application discloses a silent air compressor.

[0043] Reference Figure 1 , Figure 2 and Figure 3 A silent air compressor comprises a crankcase, in which a crankshaft 1 is rotatably arranged, two primary cylinders 2 are arranged on one side of the crankcase, and two secondary cylinders 3 are arranged on the other side, a primary piston 4 is telescopically arranged in the primary cylinder 2, a primary connecting rod 5 is connected between the primary piston 4 and the crankshaft 1, a secondary piston 6 is telescopically arranged in the secondary cylinder 3, and a secondary connecting rod 7 is connected between the secondary piston 6 and the crankshaft 1, a motor 8 for driving the crankshaft 1 to rotate is arranged at one end of the crankcase, and a cooler 9 for cooling compressed air is arranged at the other end, a fan blade 10 is arranged on the side of the cooler 9 close to the crankcase, and the fan blade 10 is drivingly connected to the crankshaft 1, a shock-absorbing pad 44 is installed at the bottom of the motor 8 and the crankcase, and a mounting fixing plate 45 is installed at the top of the motor 8 and the crankcase.

[0044] When in use, the compressor is fixed on the motor vehicle by the shock-absorbing pad 44 and the mounting plate 45, the motor 8 drives the crankshaft 1 to rotate, and the crankshaft 1 drives the primary piston 4 and the secondary piston 6 to move through the primary connecting rod 5 and the secondary connecting rod 7, so as to complete the suction, primary air compression and secondary air compression, and the compressed air passes through the cooler 9. The rotation of the crankshaft 1 drives the fan blades 10 to rotate at the same time, and the air is used to cool the cooler 9, thereby achieving the cooling of the compressed air.

[0045] Reference Figure 1 , Figure 2 and Figure 3 The cooler 9 is a combined cooler. The cooler 9 has two independent air inlets and air outlets. The two independent air inlets and air outlets are respectively used to cool the air compressed in the first stage and the air compressed in the second stage. A hollow square tube is connected between the exhaust ports of the two first-stage cylinders 2. The end of the hollow square tube close to the cooler 9 is connected to a first-stage air guide pipe 40. The first-stage air guide pipe 40 is connected to the first air inlet of the cooler 9. The first air outlet of the cooler 9 is connected to a first-stage air supply pipe 41. The end of the first-stage air supply pipe 41 away from the cooler 9 is connected to a hollow square tube. The first-stage air supply pipe 41 is connected to the air intake ports of the two second-stage cylinders 3 through the hollow square tube. A hollow square tube is also connected between the exhaust ports of the two second-stage cylinders 3. The hollow square tube is far away from the second-stage air guide pipe 42. The second-stage air guide pipe 42 is connected to the second air inlet of the cooler 9. The second air outlet of the cooler 9 is connected to the second air supply pipe 43. Figure 2 and Figure 5 The primary air guide pipe 40, the primary air delivery pipe 41, the secondary air guide pipe 42 and the air delivery pipe are all configured as hollow sandwich conduits. In the above scheme, the two cylinders on one side are connected by a hollow square tube to improve the stability of the overall structure. The hollow square tube is not only used to transport compressed air, but also serves as a connection reinforcement and reduces the vibration and noise of the cylinder. Among them, the hollow sandwich conduit is used to reduce the transmission of noise generated when compressed air is transported in the pipe to the outside.

[0046] Reference Figure 3 and Figure 6 The crankcase includes a case body 11, and a crankshaft cavity 12 is opened through the case body 11 along the length direction thereof. First interlayer grooves 13 are symmetrically opened at both ends of the case body 11, and an end plate 14 is detachably connected to the end of the case body 11 close to the cooler 9. An intermediate bracket 15 is installed between the end of the case body 11 close to the motor 8 and the motor 8, and a second interlayer groove 29 is opened at one end of the intermediate bracket 15. The designs of the first interlayer groove 13 and the second interlayer groove 29 are respectively to realize the interlayer structure of the case body 11 and the intermediate bracket 15, thereby improving the sound insulation and noise reduction performance of the case body 11 and the intermediate bracket 15.

[0047] Reference Figure 3 and Figure 4A first noise reduction plate 16 is fixed to the side of the end plate 14 close to the box body 11, and a first axial hole 17 for passing the crankshaft 1 is penetrated on the first noise reduction plate 16. A second noise reduction plate 18 is fixed to the side of the intermediate bracket 15 close to the box body 11, and a second axial hole 19 for passing the crankshaft 1 is penetrated on the second noise reduction plate 18. Both the first noise reduction plate 16 and the second noise reduction plate 18 are metal sheets and are fixed by bolts. During use, a sandwich space is formed between the first noise reduction plate 16 and the end plate 14, and a sandwich space is also formed between the second noise reduction plate 18 and the intermediate bracket 15. If the noise in the crankcase is transmitted to the outside through the two ends of the crankcase, it needs to pass through the sandwich space, and the sandwich space has a good sound insulation function, so it can greatly prevent the noise in the crankcase from being transmitted through the ends of the crankcase.

[0048] Reference Figure 3 and Figure 4 The crankshaft 1 is connected to the first noise reduction plate 16 bearing, and a first end seal 20 is fixed on the side of the first noise reduction plate 16 away from the housing 11, and the first end seal 20 is sleeved on the crankshaft 1. A sandwich guide plate 21 is fixed by bolts on the side of the end plate 14 away from the housing 11, and the end of the crankshaft 1 passes through the sandwich guide plate 21, and a second end seal 22 is fixed on the sandwich guide plate 21, and the second end seal 22 is sleeved on the crankshaft 1, wherein the first end seal 20 and the second end seal 22 are used to prevent external dust or water from entering the crankcase, and at the same time reduce the transmission of noise in the crankcase to the outside, and a sandwich space is formed between the sandwich guide plate 21 and the end plate 14, which further improves the performance of sound insulation and noise reduction.

[0049] Reference Figure 3 and Figure 5 The first-stage cylinder 2 includes a first-stage cylinder body 30 detachably mounted on the box body 11. An outlet valve assembly 31 is provided at an opening at one end of the first-stage cylinder body 30 away from the box body 11. The specific structural design of the outlet valve assembly 31 can be found in the Chinese patent with the patent publication number CN113339241B and the patent name of a compressor mounting box body 11 and a three-stage air compressor using the box body 11, as well as the relevant records in the specification. The first-stage piston 4 is an internal suction piston. The specific structural design of the first-stage piston 4 can be found in the Chinese patent with the patent publication number CN113339241B and the patent name of a compressor mounting box body 11 and a three-stage air compressor using the box body 11. Figure 8 , Fig. 9 10, 11 and the related records in the specification, since the specific structure of the outlet valve assembly 31 and the first-stage piston 4 is disclosed in detail in the previously applied patent, this application does not repeat the structural description, refer to Figure 3 and Figure 8A first-level valve cover 32 is installed on the side of the exhaust valve assembly 31 away from the cylinder body, and a third interlayer groove 33 is opened on the side of the first-level valve cover 32 away from the first-level cylinder body 30. A first-level groove cover 34 for closing the third interlayer groove 33 is detachably installed on the side of the first-level valve cover 32 away from the first-level cylinder body 30. With the above scheme, the third interlayer groove 33 is a hollow interlayer, which reduces the cost of the first-level valve cover 32 and improves the sound insulation and noise reduction performance of the first-level valve cover 32.

[0050] Reference Figure 3 and Figure 7 A coupling 23 is connected between the output shaft of the motor 8 and the crankshaft 1, and the coupling 23 is located in the intermediate bracket 15. A support plate 24 is fixed to the side of the intermediate bracket 15 close to the case 11. A third axial hole 25 is penetrated through the support plate 24, and the end of the crankshaft 1 is penetrated in the third axial hole 25. The support plate 24 is provided with a plurality of connecting holes 26 connected with the case 11 on the side of the second axial hole 19. An air supply hole 27 connected with the connecting hole 26 is provided on the side wall of the intermediate bracket 15, and an air filter 28 is connected to the air supply hole 27. In use, the first-stage piston 4 inhales air from the crankcase, thereby accelerating the air flow in the crankcase, which is beneficial to reducing the temperature in the crankcase. At the same time, the outside air enters the intermediate bracket 15 through the air filter 28 and then enters the crankcase, so the intermediate bracket 15 is also cooled.

[0051] Reference Figure 3 and Fig. 9 , the secondary cylinder 3 is detachably mounted on the secondary cylinder body 35 on the box body 11, and a ventilation valve assembly 36 is arranged at the opening of one end of the secondary cylinder body 35 away from the box body 11. For the specific structural design of the ventilation valve assembly 36, please refer to Figures 16, 17, 18, 19 of the Chinese patent with patent publication number CN113339241B and the name of the patent, which is a compressor mounting box body 11 and a three-stage air compressor using the box body 11, as well as the relevant records in the specification. A secondary valve cover 37 is installed on the side of the ventilation valve assembly 36 away from the secondary cylinder body 35, and a fourth interlayer groove 38 is opened on the side of the secondary valve cover 37 away from the secondary cylinder body 35. A secondary groove cover 39 for closing the fourth interlayer groove 38 is detachably mounted on the side of the secondary valve cover 37 away from the secondary cylinder body 35. By adopting the above scheme, the fourth interlayer groove 38 forms a hollow interlayer, which reduces the cost of the secondary valve cover 37 and improves the sound insulation and noise reduction performance of the secondary valve cover 37.

[0052] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A silent air compressor, characterized in that: The invention comprises a crankcase, wherein a crankshaft (1) is arranged in the crankcase, two primary cylinders (2) are arranged on one side of the crankcase, and two secondary cylinders (3) are arranged on the other side, a primary piston (4) is arranged in the primary cylinder (2), a primary connecting rod (5) is arranged between the primary piston (4) and the crankshaft (1), a secondary piston (6) is arranged in the secondary cylinder (3), a secondary connecting rod (7) is arranged between the secondary piston (6) and the crankshaft (1), a motor (8) for driving the crankshaft (1) to rotate is arranged at one end of the crankcase, and a motor (8) for cooling the compressor is arranged at the other end. An air cooler (9), wherein a fan blade (10) is arranged on a side of the cooler (9) close to the crankcase, and the fan blade (10) is drivingly connected to the crankshaft (1). The crankcase comprises a case (11), and a crankshaft cavity (12) is opened through the case (11) along its length direction. First interlayer grooves (13) are symmetrically opened at both ends of the case (11). An end of the case (11) close to the cooler (9) is detachably connected to an end plate (14), and an intermediate bracket (15) is installed between the end of the case (11) close to the motor (8) and the motor (8).

2. A silent air compressor according to claim 1, characterized in that: A first noise reduction plate (16) is fixed to a side of the end plate (14) close to the inside of the housing (11), and a first axial hole (17) for passing the crankshaft (1) is formed through the first noise reduction plate (16). A second noise reduction plate (18) is fixed to a side of the intermediate bracket (15) close to the inside of the housing (11), and a second axial hole (19) for passing the crankshaft (1) is formed through the second noise reduction plate (18).

3. A silent air compressor according to claim 2, characterized in that: The crankshaft (1) is connected to the bearing of the first noise reduction plate (16); a first end seal (20) is fixed to a side of the first noise reduction plate (16) away from the housing (11); the first end seal (20) is sleeved on the crankshaft (1); a sandwich guide plate (21) is fixed to a side of the end plate (14) away from the housing (11); an end of the crankshaft (1) passes through the sandwich guide plate (21); a second end seal (22) is fixed to the sandwich guide plate (21); and the second end seal (22) is sleeved on the crankshaft (1).

4. A silent air compressor according to claim 2 or 3, characterized in that: The first-stage piston (4) is an internally aspirated piston. A coupling (23) is connected between the output shaft of the motor (8) and the crankshaft (1). The coupling (23) is located in the intermediate bracket (15). A support plate (24) is fixed on a side of the intermediate bracket (15) close to the housing (11). A third axial hole (25) is formed through the support plate (24). The end of the crankshaft (1) is inserted into the third axial hole (25). The support plate (24) is provided with a plurality of connecting holes (26) connected to the housing (11) on the circumference of the second axial hole (19). An air supply hole (27) connected to the connecting hole (26) is formed on the side wall of the intermediate bracket (15). The air supply hole (27) is connected to an air filter (28).

5. A silent air compressor according to claim 4, characterized in that: A second interlayer groove (29) is formed at one end of the intermediate bracket (15).

6. A silent air compressor according to claim 4, characterized in that: The primary cylinder (2) comprises a primary cylinder body (30) detachably mounted on the box body (11); an air outlet valve assembly (31) is arranged at an opening at one end of the primary cylinder body (30) away from the box body (11); a primary valve cover (32) is installed at a side of the air outlet valve assembly (31) away from the cylinder body; a third interlayer groove (33) is opened at a side of the primary valve cover (32) away from the primary cylinder body (30); and a primary groove cover (34) for closing the third interlayer groove (33) is detachably mounted at a side of the primary valve cover (32) away from the primary cylinder body (30).

7. A silent air compressor according to claim 4, characterized in that: The secondary cylinder (3) is a secondary cylinder body (35) detachably mounted on the housing (11); a ventilation valve assembly (36) is provided at an opening at one end of the secondary cylinder body (35) away from the housing (11); a secondary valve cover (37) is installed at a side of the ventilation valve assembly (36) away from the secondary cylinder body (35); a fourth interlayer groove (38) is provided at a side of the secondary valve cover (37) away from the secondary cylinder body (35); and a secondary groove cover (39) for closing the fourth interlayer groove (38) is detachably mounted at a side of the secondary valve cover (37) away from the secondary cylinder body (35).

8. A silent air compressor according to claim 1, characterized in that: The cooler (9) is a combined cooler, wherein the exhaust ports of the two first-level cylinders (2) are connected to a first-level air guide pipe (40), the first-level air guide pipe (40) is connected to a first air inlet of the cooler (9), the first air outlet of the cooler (9) is connected to a first-level air supply pipe (41), the first-level air supply pipe (41) is connected to the air intake ports of the two second-level cylinders (3), the exhaust ports of the two second-level cylinders (3) are connected to a second-level air guide pipe (42), the second-level air guide pipe (42) is connected to a second air inlet of the cooler (9), and the second air outlet of the cooler (9) is connected to a second-level air supply pipe (43).

9. A silent air compressor according to claim 8, characterized in that: The primary air guide tube (40), the primary air supply tube (41), the secondary air guide tube (42) and the air supply tube are all configured as hollow sandwich tubes.

10. A silent air compressor according to claim 1, characterized in that: Shock-absorbing pads (44) are installed at the bottom of the motor (8) and the crankcase, and mounting fixing plates (45) are installed at the top of the motor (8) and the crankcase.

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