Air compressor

Abstract

The utility model provides an air compressor, and belongs to the technical field of air compression. The air compressor comprises a brushless motor, a crank, a rack, a bearing support, a first compression assembly, a second compression assembly, a third bearing and a fourth bearing. The brushless motor comprises a rotor assembly, the rotor assembly comprises a motor shaft, the first compression assembly comprises a first connecting rod, a first bearing, a first piston and a first air cylinder, and the second compression assembly comprises a second connecting rod, a second bearing, a second piston and a second air cylinder; the motor shaft can drive the first connecting rod and the second connecting rod to move, the first piston can be driven by the first connecting rod to do reciprocating motion in the first air cylinder, the second piston can be driven by the second connecting rod to do reciprocating motion in the second air cylinder, the crank is fixedly connected with the motor shaft, and the brushless motor is fixedly installed on the rack. The application is beneficial to improving the conditions of low transmission efficiency and high energy consumption of the motor.

Description

Technical Field

[0001] The utility model relates to the technical field of air compression, in particular to an air compressor. Background Art

[0002] In industrial production, air compressors are used as power sources and are widely applied. Among them, air compressors with double compression components are widely used in many working conditions that require faster working speeds and higher working efficiencies due to their faster working speeds, higher powers and efficiencies.

[0003] For a conventional air compressor with double compression components, the two compression components are located at opposite ends of the air compressor. The motor uses a brush-type series-wound motor with a relatively high rotational speed, and the maximum rotational speed can reach a high speed of 14,000 rpm. Moreover, because the rotational speed of the brush-type series-wound motor fluctuates greatly, generally, the brush-type series-wound motor is combined with a belt drive mechanism to drive the air compressor to work to ensure the working conditions performance at high rotational speeds. As shown in the attached drawings of the background art, however, this belt drive method is prone to problems such as slipping, resulting in low transmission efficiency and high energy consumption; in some working scenarios, the motor needs to work at a low rotational speed (about 3,200 rpm). Due to the existence of the belt drive mechanism, the transmission efficiency is low and the energy consumption is high, and the effect is not ideal in actual industrial operations. Summary of the Utility Model

[0004] Aiming at the problems existing in the prior art, the utility model provides an air compressor, which is conducive to improving the situation of low motor transmission efficiency and high energy consumption.

[0005] The utility model is realized through the following technical solutions:

[0006] An air compressor, comprising a brushless motor, a crank, a frame, a bearing bracket, a first compression assembly, a second compression assembly, a third bearing, and a fourth bearing. The brushless motor includes a rotor assembly, and the rotor assembly includes a motor shaft. The first compression assembly includes a first connecting rod, a first bearing, a first piston, and a first cylinder. The second compression assembly includes a second connecting rod, a second bearing, a second piston, and a second cylinder. The motor shaft can drive the first connecting rod and the second connecting rod to move. The first piston can reciprocate in the first cylinder driven by the first connecting rod, and the second piston can reciprocate in the second cylinder driven by the second connecting rod. The crank is fixedly connected to the motor shaft. One end of the first connecting rod away from the first piston is rotatably connected to the crank through the first bearing. One end of the second connecting rod away from the second piston is rotatably connected to the crank through a part of the second bearing. The brushless motor is fixedly installed on the frame. The third bearing cooperates with the motor shaft. The bearing bracket is provided with a first bearing receiving cavity for receiving the third bearing. The frame is provided with a second bearing receiving cavity for receiving the fourth bearing, and the fourth bearing cooperates with the motor shaft.

[0007] Preferably, the brushless motor further includes a stator assembly. The brushless motor is clamped and fixed by the bearing bracket and the frame, and the stator assembly is fixed on the frame by the bearing bracket. The motor shaft is provided with straight knurling, which is located on the circumferential side of the end of the motor shaft facing the crank. A flat position is provided at the straight knurling of the motor shaft. The crank is provided with a first threaded hole. The motor shaft and the crank are fixed together by a first screw. The first screw is screwed into the first threaded hole and abuts against the flat position.

[0008] Preferably, the rotor assembly further includes a rotor core, a plurality of magnets, a first baffle, and a second baffle. The plurality of magnets are attached to the rotor core. The motor shaft is provided with a plurality of straight protrusions. The motor shaft passes through the first baffle, the second baffle, and the rotor core. The rotor core, the first baffle, and the second baffle are fixed on the motor shaft by interference fit with the plurality of straight protrusions on the motor shaft. The first baffle and the second baffle are located on opposite sides of the rotor core in the axial direction, and the plurality of magnets are blocked between the first baffle and the second baffle. The motor shaft is fixedly connected to the rotor core. The bearing bracket is provided with a first through hole, and the first through hole extends in a direction away from the crank through the first bearing receiving cavity.

[0009] Preferably, the rotor assembly also includes a rotor core, a plurality of magnets, a first baffle, and a second baffle. A plurality of magnet mounting grooves are circumferentially opened on the rotor core, and the openings of the plurality of magnet mounting grooves shrink along the direction away from the central axis of the motor shaft. The magnet mounting grooves are used to accommodate magnets, and both sides of the bottom of the plurality of magnet mounting grooves are provided with glue retaining grooves; the first baffle and the second baffle are located on opposite sides of the rotor core in the axial direction, the first baffle blocks one side of the plurality of magnets, and the second baffle blocks the other opposite side of the plurality of magnets.

[0010] Preferably, the brushless motor includes a rotor core, the rotor core has a plurality of ventilation holes, the extension direction of the ventilation holes is parallel to the motor shaft, the first baffle has a plurality of first through holes connected to the ventilation holes, and the second baffle has a plurality of second through holes connected to the ventilation holes.

[0011] Preferably, the brushless motor includes a stator assembly, which includes a first insulating skeleton, a second insulating skeleton, and a stator core, wherein the first insulating skeleton includes a plurality of first insulating surfaces and a plurality of first insulating teeth, wherein the plurality of first insulating surfaces are recessed to form a plurality of first grooves, and the plurality of first grooves are located between two adjacent first insulating teeth of the first insulating skeleton; the second insulating skeleton includes a plurality of second insulating surfaces and a plurality of second insulating teeth, wherein the plurality of second insulating surfaces are recessed to form a plurality of second grooves, and the plurality of second grooves are located between two adjacent second insulating teeth of the second insulating skeleton; the stator core includes a plurality of stator core teeth, wherein a plurality of accommodating cavities are formed between adjacent stator core teeth, and the plurality of accommodating cavities are used to accommodate and engage the plurality of first insulating teeth and the plurality of second insulating teeth, wherein the first insulating skeleton and the second insulating skeleton are located on both sides of the stator core and are engaged with the stator core, and the plurality of first grooves and the plurality of second grooves are covered by the tooth surfaces of the stator core teeth.

[0012] Preferably, the frame includes a plurality of flanges, the plurality of flanges are distributed in an annular shape, a plurality of the flanges are provided with engaging grooves toward the annular center, a plurality of the engaging grooves are located on the side of the flange facing the annular center and at the end of the flange, a plurality of the engaging grooves are used to accommodate the stator core, and the bearing bracket clamps the stator core in the engaging groove at the bottom end of the engaging groove under the action of the plurality of the flanges.

[0013] Preferably, the brushless motor includes a stator assembly, the frame includes a plurality of first bosses, the first bosses are arranged on the flange, the first bosses are located on the side of the flange away from the stator assembly, the first bosses extend in a direction away from the stator assembly, and the bearing bracket includes a plurality of second bosses, and the first bosses are connected and fastened to the second bosses by fasteners.

[0014] Preferably, it further includes a first fan and a second fan. The first fan is located at the end of the motor shaft away from the crank, and the second fan is located at the end of the crank away from the first fan. The first compression assembly further includes a first cylinder head, and the second compression assembly further includes a second cylinder head. The first cylinder and the first cylinder head are arranged in sequence and fixed together by fastening elements. The second cylinder and the second cylinder head are arranged in sequence and fixed together by fastening elements. The bearing bracket has a plurality of ventilation openings. The rotational speed range of the brushless motor is 2900 - 3500 rpm.

[0015] Preferably, the distance between the central axis of the first bearing and the central axis of the motor shaft is greater than the distance between the central axis of the second bearing and the central axis of the motor shaft. A gasket is provided between the first bearing and the second bearing, and the gasket closely adheres to the inner rings of the first bearing and the second bearing.

[0016] Preferably, the first fan has a first fan threaded hole, and the end of the motor shaft away from the crank is provided with a first threaded portion that is threadedly engaged with the first fan threaded hole. On the side of the second fan facing away from the crank, an annular groove is formed, and on the other side of the second fan, a polygonal groove is formed. The second fan further includes a locking hole that communicates the annular groove and the polygonal groove. The diameter of the locking hole is smaller than the dimensions of the annular groove and the polygonal groove. The locking hole, the annular groove, and the polygonal groove on the second fan together form a locking flange. The air compressor further includes a locking member and a fixing member. The locking member includes a first engaging portion and a second engaging portion. The first engaging portion and the second engaging portion are respectively located at both ends of the locking member. The locking member is provided with a stepped hole that penetrates the first engaging portion and the second engaging portion. The first engaging portion includes an annular flange, a locking groove, and a polygonal flange. The annular flange can fall into the annular groove, the locking groove is used to accommodate the locking flange, and the polygonal flange can fall into the polygonal groove. The second engaging portion includes an engaging cylinder and a plurality of engaging teeth. The plurality of engaging teeth are located at the end of the engaging cylinder facing away from the first engaging portion. The outer peripheral dimension of the first engaging portion is greater than the outer peripheral dimension of the second engaging portion. The first engaging portion and the second engaging portion form an abutting flange, and the abutting flange tightly abuts against the outer side surface of the inner ring of the second bearing. The second engaging portion falls into a part of the inner ring of the second bearing. The crank includes a second threaded hole and a plurality of tooth grooves. The second threaded hole is located at the end of the crank away from the first fan, and the plurality of tooth grooves are located on the end surface of the crank away from the first fan. The plurality of tooth grooves are used to accommodate the plurality of engaging teeth. The fixing member includes a second threaded portion and an extension portion. The second threaded portion is threadedly engaged with the second threaded hole, and the extension portion tightly abuts against the end surface of the stepped hole.

[0017] Preferably, the frame further includes a spacer portion. The spacer portion is provided with a second bearing receiving hole and a plurality of through holes. The plurality of through holes surround the second bearing receiving hole. The frame is provided with a second through hole located in the spacer portion and on the side of the second bearing receiving hole close to the crank. The motor shaft passes through the second bearing receiving hole and the second through hole.

[0018] By replacing the brushed motor with a brushless motor, removing the belt drive mechanism, providing a crank fixed to the motor shaft, and providing a first connecting rod rotatably connected to the crank through a first bearing and a second connecting rod rotatably connected to the crank through a part of a second bearing, the driving mode of the motor for the first connecting rod and the second connecting rod is improved to crank direct drive, improving the situation of low motor transmission efficiency and high energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a perspective view of an air compressor of the prior art;

[0020] Figure 2 is a perspective view of the air compressor of the present application;

[0021] Figure 3 is a perspective view of the air compressor of the present application from another angle;

[0022] Figure 4 is a perspective view of the air compressor of the present application with the first fan removed;

[0023] Figure 5 is a perspective view of the air compressor of the present application with the first fan, bearing bracket, etc. removed;

[0024] Figure 6 is an exploded view of the stator assembly of the air compressor of the present application;

[0025] Figure 7 is an enlarged exploded view of the stator assembly of the air compressor of the present application from the opposite perspective;

[0026] Figure 8 is a perspective view of the air compressor of the present application with the first fan, bearing bracket, stator assembly, etc. removed;

[0027] Figure 9 is an exploded view of the rotor assembly of the air compressor of the present application;

[0028] Figure 10 is a perspective view of the rotor core of the air compressor of the present application;

[0029] Figure 11 is a sectional view of the air compressor of the present application;

[0030] Figure 12Partial enlarged sectional view of the air compressor of the present application;

[0031] Figure 13 Exploded view of the motor shaft, crank, etc. of the air compressor of the present application;

[0032] Figure 14 Exploded view of the motor shaft, crank, bearing bracket, etc. of the air compressor of the present application;

[0033] Figure 15 Exploded sectional view of the crank, second fan, fixing parts, etc. of the air compressor of the present application;

[0034] Figure 16 Stereogram of the frame of the air compressor of the present application;

[0035] Figure 17 Stereogram of the second fan of the air compressor of the present application from the opposite perspective;

[0036] Figure 18 Stereogram of the crank and locking parts of the air compressor of the present application. Detailed implementation mode

[0037] According to Figure 1-18 As shown, the air compressor includes a first compression assembly 2, a second compression assembly 7, a brushless motor 3, a crank 4, a frame 5, a bearing bracket 6, a third bearing 61, and a fourth bearing 8. The air compression method of the air compressor is two-stage compression. The first compression assembly 2 inputs the initially compressed air to the second compression assembly 7, and the second compression assembly 7 performs secondary compression on the air that has been initially compressed and then outputs it. The brushless motor 3 is located between the first compression assembly 2 and the second compression assembly 7. The brushless motor 3 is fixedly installed on one side of the frame 5. The brushless motor 3 includes a rotor assembly 31. The rotor assembly 31 includes a motor shaft 311. The crank 4 is fixedly and detachably sleeved on one end of the motor shaft 311. In this embodiment, the brushless motor 3 can be driven by direct current or alternating current. According to the design of the maximum efficiency of the brushless motor 3, the rotational speed range of the brushless motor 3 is 2900 - 3500 rpm.

[0038] The first compression assembly 2 includes a first connecting rod 21, a first bearing 211, a first piston 22, and a first cylinder 23. One end of the first connecting rod 21 is fixedly connected to the first piston 22, and the end of the first connecting rod 21 away from the first piston 22 is rotatably connected to the crank 4 through the first bearing 211. The first piston 22 can reciprocate in the first cylinder 23 under the drive of the first connecting rod 21.

[0039] The second compression assembly 7 includes a second connecting rod 71, a second bearing 711, a second piston 72, and a second cylinder 73. One end of the second connecting rod 71 is fixedly connected to the second piston 72, and the other end of the second connecting rod 71 away from the second piston 72 is rotationally connected to the crank 4 through a part of the second bearing 711. The second piston 72 can reciprocate in the second cylinder 73 driven by the second connecting rod 71. The rotation of the motor shaft 311 can drive the rotation of the crank 4, thereby driving the movement of the first connecting rod 21 and the second connecting rod 71, and further driving the movement of the first piston 22 and the second piston 72 in the first cylinder 23 and the second cylinder 73 to compress air. This way of directly driving the rotation of the crank 4 by the motor shaft 311 and then driving the movement of the first connecting rod 21 and the second connecting rod 71 improves the low motor transmission efficiency and high energy consumption situation.

[0040] The brushless motor 3 is fixedly installed on the frame 5. The bearing bracket 6 is provided with a first bearing receiving cavity 62 for receiving a third bearing 61, and the third bearing 61 is located in the first bearing receiving cavity 62. The bearing bracket 6 is provided with a first through hole 621 that penetrates the first bearing receiving cavity 62 and extends in a direction away from the crank 4. The motor shaft 311 penetrates the first bearing receiving cavity 62 and the first through hole 621, and the motor shaft 311 passes through the first through hole 621 and cooperates with the third bearing 61, so that the motor shaft 311 of the brushless motor 3 rotates smoothly.

[0041] The frame 5 further includes a spacer portion 54. The spacer portion 54 is provided with a second bearing receiving cavity 541, a second through opening 542, and a plurality of through ports 543. The second bearing receiving cavity 541 is used for receiving a fourth bearing 8, and the fourth bearing 8 cooperates with the motor shaft 311. The plurality of through ports 543 surround the second bearing receiving cavity 541. The second through opening 542 is located on the side of the second bearing receiving cavity 541 close to the crank 4. The motor shaft 311 penetrates the second bearing receiving cavity 541 and the second through opening 542, and the motor shaft 311 cooperates with the fourth bearing 8 so that the motor shaft 311 of the brushless motor 3 rotates smoothly.

[0042] The motor shaft 311 is provided with a straight knurl 3111. The straight knurl 3111 is located on the circumferential side of one end of the motor shaft 311 facing the crank 4, and a flat portion 3112 is provided at the position where the straight knurl 3111 is provided on the motor shaft 311. The crank 4 is provided with a first threaded hole 41. The motor shaft 311 and the crank 4 are fixed together by a first screw 42. The first screw 42 is screwed into the first threaded hole 41 and abuts against the flat portion 3112.

[0043] The rotor assembly 31 of the brushless motor 3 further includes a rotor core 312, a plurality of magnets 313, a first baffle 314, and a second baffle 315. The plurality of magnets 313 are attached to the rotor core 312. By using a suitable attachment method to fix the plurality of magnets 313 on the rotor core 312, the brushless motor 3 can achieve the effect of normal operation. In this embodiment, the method of attaching the plurality of magnets 313 to the rotor core 312 is as follows: A plurality of magnet mounting grooves 3121 are circumferentially formed on the rotor core 312. The openings of the plurality of magnet mounting grooves 3121 contract along the direction away from the axis of the rotor core 312. Glue-retaining grooves 3122 are formed on both sides of the magnet mounting groove 3121. The magnet mounting groove 3121 is used to accommodate the magnet 313. When installing the magnet 313, glue is usually applied to the side of the magnet 313 facing the bottom surface of the magnet mounting groove 3121 to increase the fixing effect between the magnet 313 and the rotor core 312. The formed glue-retaining grooves 3122 are beneficial for accommodating glue residues when the magnet 313 is installed in the magnet mounting groove 3121, preventing the magnet 313 from completely squeezing out the glue from the magnet mounting groove 3121. The remaining glue increases the bonding firmness between the magnet 313 and the rotor core 312. Also, because the opening of the magnet mounting groove 3121 contracts along the direction away from the axis of the rotor core 312, the magnet 313 is firmly fixed in the magnet mounting groove 3121. The material of the magnet 313 can be a magnetic steel or other equivalent substitutes. In this embodiment, the materials of the magnets 313 are all magnetic steels.

[0044] The motor shaft 311 passes through the first baffle 314, the second baffle 315, and the rotor core 312. A plurality of straight-grooved protrusions 3114 are provided on the motor shaft 311. The rotor core 312, the first baffle 314, and the second baffle 315 are fixed on the motor shaft 311 by interference fit with the plurality of straight-grooved protrusions 3114 on the motor shaft 311. The first baffle 314 and the second baffle 315 are located on opposite sides of the rotor core 312 in the axial direction. The plurality of magnets 313 are located between the first baffle 314 and the second baffle 315. The first baffle 314 and the second baffle 315 can either block both sides of the plurality of magnets 313 and tightly abut against the plurality of magnets 313 at the same time, or the first baffle 314 and the second baffle 315 do not contact both sides of the plurality of magnets 313 and only play a certain limiting role. In this embodiment, the first baffle 314 is blocked on one side of the plurality of magnets 313, and the second baffle 315 is blocked on the opposite side of the plurality of magnets 313, achieving the effect of the first baffle 314 and the second baffle 315 tightly abutting against and fixing the magnet 313 at the same time.

[0045] The rotor core 312 is provided with a plurality of ventilation holes 3123, the extending direction of the ventilation holes 3123 is parallel to the motor shaft 311, a plurality of first through holes 3141 communicating with the ventilation holes 3123 are provided on the first baffle 314, and a plurality of second through holes 3151 communicating with the ventilation holes 3123 are provided on the second baffle 315. In this embodiment, the number of the ventilation holes 3123 is ten, which are evenly distributed along the circumferential direction of the rotor core 312, the magnetic density of the rotor core 312 is not saturated, and the rotor core 312 works normally in the brushless motor 3; on the one hand, the ventilation holes 3123 can reduce the mass of the rotor core 312 and reduce the moment of inertia of the rotor core 312; on the other hand, the provided ventilation holes 3123 are beneficial to the air flow flowing through the ventilation holes 3123 to take away the heat of the rotor core 312, which is beneficial to reducing the temperature of the rotor core 312.

[0046] The brushless motor 3 further includes a stator assembly 32, the stator assembly 32 includes a first insulating skeleton 321, a second insulating skeleton 322, and a stator core 323. The first insulating skeleton 321 includes a plurality of first insulating surfaces 3213 and a plurality of first insulating tooth portions 3212. A plurality of first grooves 3211 are formed by the depression of the plurality of first insulating surfaces 3213, and the plurality of first grooves 3211 are located between two adjacent first insulating tooth portions 3212 of the first insulating skeleton 321; the second insulating skeleton 322 includes a plurality of second insulating surfaces 3223 and a plurality of second insulating tooth portions 3222. A plurality of second grooves 3221 are formed by the depression of the plurality of second insulating surfaces 3223, and the plurality of second grooves 3221 are located between two adjacent second insulating tooth portions 3222 of the second insulating skeleton 322. The stator core 323 includes a plurality of stator core tooth portions 3231, and a plurality of accommodating cavities 3232 are formed between adjacent stator core tooth portions 3231. The plurality of accommodating cavities 3232 are used for accommodating and fitting a plurality of first insulating tooth portions 3212 and a plurality of second insulating tooth portions 3222. The first insulating skeleton 321 and the second insulating skeleton 322 are located on both sides of the stator core 323 and are both fitted with the stator core 323. The plurality of first grooves 3211 and the plurality of second grooves 3221 are covered by the tooth surfaces of the stator core tooth portions 3231. The first grooves 3211 are beneficial to reducing the contact area of the joint surface between the stator core 323 and the first insulating skeleton 321, and the second grooves 3221 are beneficial to reducing the contact area of the joint surface between the stator core 323 and the second insulating skeleton 322. When windings are wound on the first insulating skeleton 321 and the second insulating skeleton 322, the first insulating skeleton 321 and the second insulating skeleton 322 will generate corresponding deformations. The provided first grooves 3211 and second grooves 3221 are beneficial to ensuring the flat installation of the first insulating skeleton 321 and the second insulating skeleton 322 with the stator core 323.

[0047] The stator assembly 32 is fixed to the frame 5 by the bearing bracket 6. Furthermore, the stator core 323 is fixed to the frame 5 by the bearing bracket 6, so that the bearing bracket 6 fixes the stator assembly 32. The brushless motor 3 is clamped and fixed to the frame 5 by the bearing bracket 6.

[0048] The frame 5 includes a plurality of flanges 51, which are distributed in an annular shape. A snap-fit groove 511 is formed on the plurality of flanges 51 toward the annular center. The plurality of snap-fit grooves 511 are located on the side of the flange 51 facing the annular center and at the end of the flange 51. The plurality of snap-fit grooves 511 are used to accommodate the stator core 323. Under the action of the plurality of flanges 51, the bearing bracket 6 clamps the stator core 323 located in the snap-fit groove 511 at the bottom end of the snap-fit groove 511.

[0049] The frame 5 includes a plurality of first bosses 52, which are arranged on the flange 51, and are located on the side of the flange 51 away from the stator assembly 32. The first boss 52 extends in a direction away from the stator assembly 32. The bearing bracket 6 includes a plurality of second bosses 63, and the first bosses 52 and the second bosses 63 are connected and fastened by a fastener 81. In this embodiment, the fastener 81 is a second screw. The plurality of first bosses 52 are all provided with a second threaded hole 521, and the second bosses 63 are all provided with a through hole 631 corresponding to the second threaded hole 521. The second screw penetrates the through hole 631 and is screwed with the second threaded hole 521 for fixing, so that the bearing bracket 6 can fix the stator assembly 32 on the frame 5.

[0050] The air compressor further includes a first fan 3113 and a second fan 43. The first fan 3113 is located at one end of the motor shaft 311 away from the crank 4, and the second fan 43 is located at the end of the crank 4 away from the first fan 3113. The first compression assembly 2 also includes a first cylinder head 25, and the second compression assembly 7 also includes a second cylinder head 75. The first cylinder 23 and the first cylinder head 25 are arranged in sequence and fixed together by fastening elements. The second cylinder 73 and the second cylinder head 75 are arranged in sequence and fixed together by fastening elements. The bearing bracket 6 has a plurality of vents 64. In this embodiment, the first fan 3113 is an axial flow fan, and the second fan 43 is a radial flow fan. When the first fan 3113 rotates, part of the heat dissipation airflow generated passes through the stator assembly 32, the rotor assembly 31, and the plurality of through-holes 543 from the vents 64, thereby dissipating the heat of the stator assembly 32 and the rotor assembly 31; when the second fan 43 rotates, part of the heat dissipation airflow blows on the first compression assembly 2 and the second compression assembly 7, dissipating the heat of the first compression assembly 2 and the second compression assembly 7. The first fan 3113 and the second fan 43 cooperate to achieve heat dissipation for the air compressor.

[0051] The distance between the central axis of the first bearing 211 and the central axis of the motor shaft 311 is greater than the distance between the central axis of the second bearing 711 and the central axis of the motor shaft 311; a gasket 316 is provided between the first bearing 211 and the second bearing 711, and the gasket 316 is in close contact with the inner rings of the first bearing 211 and the second bearing 711. The stroke of the first connecting rod 21 cooperating with the first bearing 211 is greater than the stroke of the second connecting rod 71 cooperating with the second bearing 711. Therefore, the first cylinder 23 serves as a primary compression cylinder, and the second cylinder 73 serves as a secondary compression cylinder. The second cylinder 73 performs secondary compression on the compressed gas of the first cylinder 23. Furthermore, the first compression assembly 2 conveys the initially compressed air to the second compression assembly 7 via the air pipeline 82. The second compression assembly 7 performs secondary compression on the initially compressed air and then outputs it, realizing the function of two-stage compression of the air compressor.

[0052] The first fan 3113 has a first fan threaded hole 31131, and a first threaded portion 3115 that is screwed and fitted with the first fan threaded hole 31131 is provided at the end of the motor shaft 311 away from the crank 4; an annular groove 431 is formed on the side of the second fan shape 43 facing away from the crank 4, and a polygonal groove 432 is formed on the other side of the second fan shape. The second fan 43 further includes a locking hole 433 that communicates the annular groove 431 and the polygonal groove 432. The diameter of the locking hole 433 is smaller than the sizes of the annular groove 431 and the polygonal groove 432. The locking hole 433, the annular groove 431, and the polygonal groove 432 on the second fan 43 together form a locking flange 434.

[0053] The air compressor further includes a locking member 1 and a fixing member 9. The locking member 1 includes a first engaging portion 11 and a second engaging portion 12. The first engaging portion 11 and the second engaging portion 12 are respectively located at both ends of the locking member 1. A stepped hole 13 that penetrates the first engaging portion 11 and the second engaging portion 12 is formed on the locking member 1. The first engaging portion 11 includes an annular flange 111, a locking groove 112, and a polygonal flange 113. The annular flange 111 can fall into the annular groove 431, the locking groove 112 is used to accommodate the locking flange 434, and the polygonal flange 113 can fall into the polygonal groove 432. The locking member 1 realizes the fixation of the locking member 1 and the second fan shape 43 through the cooperation of the annular flange 111 and the annular groove 431, the cooperation of the locking groove 112 and the locking flange 434, and the cooperation of the polygonal flange 113 and the polygonal groove 432. Among them, the locking member 1 is a hard powder metallurgy metal part, and an insert (similar to overmolding) is carried out in the mold cavity of the second fan 43.

[0054] The second engaging portion 12 includes an engaging cylinder 121 and a plurality of engaging teeth 122. The plurality of engaging teeth 122 are located at the end of the engaging cylinder 121 away from the first engaging portion 11. The outer peripheral dimension of the first engaging portion 11 is larger than that of the second engaging portion 12. The first engaging portion 11 and the second engaging portion 12 form an abutting flange 14. The abutting flange 14 tightly abuts against the outer side surface of the inner ring of the second bearing 711, and the part of the second engaging portion 12 falls into the inner ring of the second bearing 711.

[0055] The crank 4 includes a second threaded hole 44 and a plurality of tooth grooves 45. The second threaded hole 44 is located at the end of the crank 4 away from the first fan 3113. The plurality of tooth grooves 45 are located on the end surface of the crank 4 away from the first fan 3113. The plurality of tooth grooves 45 are used to accommodate the plurality of engaging teeth 122. The fixing member 9 includes a second threaded portion 91 and an extension portion 92. The second threaded portion 91 is in threaded engagement with the second threaded hole 44, and the extension portion 92 tightly abuts against the end surface of the stepped hole 13. Through the cooperation of the plurality of engaging teeth 122 and the plurality of tooth grooves 45, and the threaded engagement of the second threaded portion 91 and the second threaded hole 44, the purpose of fixing the second fan-shaped member 43 and the locking member 1 with the fixing member 9 is achieved.

[0056] The above embodiments are only preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered by the protection scope defined by the claims of the present invention.

Claims

1. An air compressor, characterized in that, It includes a brushless motor, a crank, a frame, a bearing bracket, a first compression assembly, a second compression assembly, a third bearing, and a fourth bearing. The brushless motor includes a rotor assembly, and the rotor assembly includes a motor shaft. The first compression assembly includes a first connecting rod, a first bearing, a first piston, and a first cylinder. The second compression assembly includes a second connecting rod, a second bearing, a second piston, and a second cylinder. The motor shaft can drive the first connecting rod and the second connecting rod to move. The first piston can reciprocate in the first cylinder driven by the first connecting rod. The second piston can reciprocate in the second cylinder driven by the second connecting rod. The crank is fixedly connected to the motor shaft. One end of the first connecting rod away from the first piston is rotatably connected to the crank through the first bearing. One end of the second connecting rod away from the second piston is rotatably connected to the crank through a part of the second bearing. The brushless motor is fixedly installed on the frame. The third bearing cooperates with the motor shaft. The bearing bracket is provided with a first bearing receiving hole for receiving the third bearing. The frame is provided with a second bearing receiving hole for receiving the fourth bearing. The fourth bearing cooperates with the motor shaft.

2. The air compressor according to claim 1, characterized in that, The brushless motor further includes a stator assembly. The brushless motor is clamped and fixed by the bearing bracket and the frame. The stator assembly is fixed on the frame by the bearing bracket. The motor shaft is provided with straight knurling, which is located on the circumferential side of the end of the motor shaft facing the crank. A flat position is provided at the straight knurling of the motor shaft. The crank is provided with a first threaded hole. The motor shaft and the crank are fixed together by a first screw. The first screw is screwed into the first threaded hole and abuts against the flat position.

3. The air compressor according to claim 1, characterized in that, The rotor assembly further includes a rotor core, a plurality of magnets, a first baffle, and a second baffle. The plurality of magnets are attached to the rotor core. The motor shaft is provided with a plurality of straight protrusions. The motor shaft passes through the first baffle, the second baffle, and the rotor core. The rotor core, the first baffle, and the second baffle are fixed on the motor shaft by interference fit with the plurality of straight protrusions on the motor shaft. The first baffle and the second baffle are located on opposite sides of the rotor core in the axial direction, and the plurality of magnets are blocked between the first baffle and the second baffle. The motor shaft is fixedly connected to the rotor core. The bearing bracket is provided with a first through hole, and the first through hole extends in a direction away from the crank through the first bearing receiving hole.

4. The air compressor according to claim 1, characterized in that, The rotor assembly further includes a rotor core, a plurality of magnets, a first baffle, and a second baffle. The rotor core is provided with a plurality of magnet mounting grooves along the circumferential direction. The openings of the plurality of magnet mounting grooves contract along a direction away from the central axis of the motor shaft. The magnet mounting grooves are used for receiving magnets. Glue-retaining grooves are provided on both sides of the bottom of each of the plurality of magnet mounting grooves. The first baffle and the second baffle are located on opposite sides of the rotor core in the axial direction. The first baffle blocks one side of the plurality of magnets, and the second baffle blocks the opposite side of the plurality of magnets.

5. The air compressor according to claim 1, characterized in that, The brushless motor includes a rotor core, a first baffle, and a second baffle. The first baffle and the second baffle are located on opposite sides of the rotor core in the axial direction. The rotor core is provided with a plurality of ventilation holes, and the extending direction of the ventilation holes is parallel to the motor shaft. A plurality of first through holes communicating with the ventilation holes are formed in the first baffle, and a plurality of second through holes communicating with the ventilation holes are formed in the second baffle.

6. The air compressor according to claim 1, characterized in that, The brushless motor includes a stator assembly. The stator assembly includes a first insulating skeleton, a second insulating skeleton, and a stator core. The first insulating skeleton includes a plurality of first insulating surfaces and a plurality of first insulating tooth portions. A plurality of first grooves are formed by the depression of a plurality of the first insulating surfaces, and a plurality of the first grooves are located between two adjacent first insulating tooth portions of the first insulating skeleton. The second insulating skeleton includes a plurality of second insulating surfaces and a plurality of second insulating tooth portions. A plurality of second grooves are formed by the depression of a plurality of the second insulating surfaces, and a plurality of the second grooves are located between two adjacent second insulating tooth portions of the second insulating skeleton. The stator core includes a plurality of stator core tooth portions, and a plurality of accommodation cavities are formed between adjacent stator core tooth portions. The plurality of accommodation cavities are used to accommodate and fit a plurality of first insulating tooth portions and a plurality of second insulating tooth portions. The first insulating skeleton and the second insulating skeleton are located on both sides of the stator core and are both fitted with the stator core. A plurality of the first grooves and a plurality of the second grooves are covered by the tooth surfaces of the stator core tooth portions.

7. The air compressor according to claim 6, characterized in that, The frame includes a plurality of flanges, and the plurality of flanges are annularly distributed. A plurality of engaging grooves are formed on the plurality of flanges facing the annular center. The plurality of engaging grooves are located on the side of the flange facing the annular center and at the end of the flange. The plurality of engaging grooves are used to accommodate the stator core, and the bearing bracket clamps the stator core located in the engaging groove to the bottom end of the engaging groove under the action of the plurality of flanges.

8. The air compressor according to claim 1, characterized in that, The brushless motor includes a stator assembly. The frame includes a plurality of first bosses, and the first bosses are arranged on the flanges. The first bosses are located on the side of the flange facing away from the stator assembly, and the first bosses extend in a direction away from the stator assembly. The bearing bracket includes a plurality of second bosses, and the first bosses and the second bosses are connected and fastened by fasteners.

9. The air compressor according to claim 1, wherein, It further includes a first fan and a second fan. The first fan is located at one end of the motor shaft away from the crank, and the second fan is located at the end of the crank away from the first fan. The first compression assembly further includes a first cylinder head, and the second compression assembly further includes a second cylinder head. The first cylinder and the first cylinder head are arranged in sequence and fixed together by fastening elements. The second cylinder and the second cylinder head are arranged in sequence and fixed together by fastening elements. The bearing bracket has a plurality of ventilation openings. The rotational speed range of the brushless motor is 2900 - 3500 rpm.

10. The air compressor according to claim 9, characterized in that, The distance between the central axis of the first bearing and the central axis of the motor shaft is farther than the distance between the central axis of the second bearing and the central axis of the motor shaft. A gasket is arranged between the first bearing and the second bearing, and the gasket is in close contact with the inner rings of the first bearing and the second bearing.

11. The air compressor according to claim 9, characterized in that, The first fan has a first fan threaded hole, and the end of the motor shaft away from the crank is provided with a first threaded portion threadedly matched with the first fan threaded hole; An annular groove is formed on one side of the second fan-shaped part away from the crank, and a polygonal groove is formed on the other side of the second fan-shaped part. The second fan further comprises a locking hole connecting the annular groove and the polygonal groove, wherein the aperture of the locking hole is smaller than that of the annular groove and the polygonal groove, and the locking hole, the annular groove and the polygonal groove on the second fan together form a locking flange; The air compressor also includes a locking member and a fixing member, wherein the locking member includes a first clamping portion and a second clamping portion, wherein the first clamping portion and the second clamping portion are respectively located at two ends of the locking member, wherein the locking member is provided with a stepped hole penetrating through the first clamping portion and the second clamping portion, wherein the first clamping portion includes an annular flange, a locking groove, and a polygonal flange, wherein the annular flange can fall into the annular groove, wherein the locking groove is used to accommodate the locking flange, and wherein the polygonal flange can fall into the polygonal groove; wherein the second clamping portion includes a clamping cylinder and a plurality of clamping teeth, wherein the plurality of clamping teeth are located at an end of the clamping cylinder away from the first clamping portion; wherein the outer circumferential dimension of the first clamping portion is greater than the outer circumferential dimension of the second clamping portion, wherein the first clamping portion and the second clamping portion form a contact flange, wherein the contact flange is tightly against the outer side surface of the inner ring of the second bearing, and wherein the second clamping portion is inserted into a part of the inner ring of the second bearing; The crank comprises a second threaded hole and a plurality of tooth grooves, wherein the second threaded hole is located at an end of the crank away from the first fan, and the plurality of tooth grooves are located at an end surface of the crank away from the first fan, and the plurality of tooth grooves are used to accommodate a plurality of engaging teeth; The fixing member comprises a second threaded portion and an extension portion, the second threaded portion is threadedly engaged with the second threaded hole, and the extension portion is tightly against the end surface of the stepped hole.

12. The air compressor according to claim 1, wherein, The frame also includes a spacing portion, which has a second bearing accommodating hole and a plurality of through openings, and the plurality of through openings surround the second bearing accommodating hole. The frame has a second through opening, and the second through opening is located in the spacing portion. The second through opening is located on a side of the second bearing accommodating hole close to the crank, and the motor shaft passes through the second bearing accommodating hole and the second through opening.

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