An oil-free air compressor for vehicles

Abstract

The present invention relates to the technical field of air compressors, and particularly to an oil-free air compressor for vehicles, which includes a motor, a crankcase, and at least one air compression device provided on the main shaft box. The air compression device at least includes a cylinder, a piston, a connecting rod, a drive shaft, and a crankshaft. The drive shaft is the output shaft of the motor. A connecting external thread is provided at a position on the drive shaft close to the motor. A connecting internal thread adapted to the connecting external thread is provided on one side of the rotary shaft hole of the crankshaft close to the drive motor. When the drive shaft is in a rotating state, there is a tendency for the connecting external thread and the connecting internal thread to be screwed tightly relative to each other. In this embodiment, the output shaft of the motor and the drive shaft of the air compressor are of an integral structure. Compared with the prior art method of connecting the output shaft of the motor and the drive shaft by a coupling, the defects such as vibration and noise caused by the coupling are eliminated, and its transmission stability is better and the transmission accuracy is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of air compressors, and particularly relates to an oil-free air compressor for vehicles. Background Art

[0002] An electric air compressor is the main body in an air source device. It is a device that converts the mechanical energy of a prime mover (usually an electric motor) into gas pressure energy and is a pneumatic generating device for compressed air. The common electric air compressors on the market at present have the following technical defects:

[0003] (1) The main shaft of the air compressor is connected to the output shaft of the driving electric motor through a coupling. This connection method of the coupling will cause defects such as vibration and noise;

[0004] (2) Between the crankshaft and the main shaft of the air compressor or between multiple crankshafts, they are usually connected by a coupling or a key connection or other means, and also have the defects of large vibration and high noise;

[0005] (3) The cooling performance of the air compression device is poor, resulting in limited continuous working time and limited life of the air compressor;

[0006] (4) The electric air compressors used on the market at present are mainly oil-lubricated. When the oil-lubricated air compressor exhausts, part of the lubricating oil is discharged with the compressed air, resulting in system failures such as braking. And it is necessary to be equipped with an oil cooling system, which is large in volume, occupies a large space, is heavy in weight and is prone to oil leakage failures. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an oil-free air compressor for vehicles with an improved structure to solve the technical defects of the electric air compressor in the prior art.

[0008] To solve the above technical problem, the technical solution provided by the present invention is as follows: An oil-free air compressor for vehicles, at least including an electric motor, a crankcase, and at least one air compression device provided on the main shaft box. One end of the crankcase is fixedly connected to the electric motor, and a crankcase cover is connected to the end of the crankcase away from the electric motor; The air compression device at least includes:

[0009] A cylinder, the cylinder includes a cylinder body and a piston cavity axially penetrating the cylinder body. One end of the cylinder body is fixedly connected to the crankcase, and the piston cavity is communicated with the inner cavity of the crankcase;

[0010] A piston, the piston is adapted to the piston cavity and is slidably and sealingly connected to the piston cavity;

[0011] A connecting rod, the connecting rod is provided with a crank connection end and a piston connection end, and the piston connection end is movably connected to the piston;

[0012] A crankshaft, the crankshaft is provided with a connecting rod connecting neck, the connecting rod connecting neck is movably connected to the connecting end of the crankshaft, and the crankshaft is provided with a rotating shaft hole;

[0013] It further includes a drive shaft adapted to the rotating shaft hole, the drive shaft is the output shaft of the motor, a connecting external thread is provided at a position close to the motor on the drive shaft, and a connecting internal thread adapted to the connecting external thread is provided on one side of the rotating shaft hole of the crankshaft close to the drive motor. When the drive shaft is in a rotating state, there is a tendency for the connecting external thread and the connecting internal thread to be screwed tightly relative to each other.

[0014] In a preferred embodiment, at least two air compression devices are provided on the crankcase, and the two air compression devices are correspondingly connected to the drive shaft of the crankshaft assembly. The crankshaft assembly includes a crankshaft close to the motor side and a sub-crankshaft provided on the side of the crankshaft away from the motor. The sub-crankshaft is provided with a connecting rod connecting neck and a rotating shaft hole, and the crankshaft and the sub-crankshaft are fixedly connected.

[0015] In a preferred embodiment, two air compression devices are provided on the crankcase, and the two air compression devices are arranged in a V shape.

[0016] In a preferred embodiment, a threaded connection hole is provided on the crankshaft, a light hole adapted to the threaded connection hole is provided on the sub-crankshaft, the crankshaft and the sub-crankshaft are fixedly connected by a connecting bolt, and the threaded section of the connecting bolt passes through the light hole and is threadedly connected to the threaded connection hole.

[0017] In a preferred embodiment, it further includes a heat dissipation system, the heat dissipation system is arranged on the side of the crankcase away from the motor, the heat dissipation system at least includes a heat dissipation fan and a fan cover, the fan cover is provided with a wind cavity for accommodating the heat dissipation fan and guiding the heat dissipation air, the fan cover is provided with guiding covers whose positions and numbers correspond one by one to the air compression devices, and the heat dissipation fan is fixedly connected to the drive shaft.

[0018] In a preferred embodiment, a heat dissipation end connection thread is provided at the free end of the drive shaft, the heat dissipation fan is further configured with a connecting sleeve, and the heat dissipation fan is fixedly connected to the drive shaft by a threaded connection between the connecting sleeve and the heat dissipation end connection thread. When the drive shaft is in a rotating state, there is a tendency for the connecting sleeve and the heat dissipation end connection thread to be screwed tightly relative to each other.

[0019] A preferred embodiment, wherein the crankshaft connecting end and the connecting rod neck are connected by a rolling bearing, and skeleton rubber seals are installed between the inner and outer rings on both sides of the rolling bearing; the piston at least includes a piston body, and an axially extending connecting rod cavity and a radially extending pin hole are provided inside the piston body. A piston pin is installed in the pin hole, and the piston connecting end and the piston pin are connected by a needle bearing, and sealing oil seals are installed on both sides of the needle bearing; a sealing ring groove and a guide ring groove are provided outside the piston body, a sealing ring is installed in the sealing ring groove, and a guide ring is installed in the guide ring groove. Both the sealing ring and the guide ring are made of self-lubricating and wear-resistant composite materials.

[0020] A preferred embodiment, wherein a plurality of first heat dissipation fins are provided outside the cylinder body, and an intake chamber surrounding the piston chamber is provided inside the cylinder body. The intake chamber is open on the lower end surface of the piston body, and an air outlet is provided on the upper end surface of the piston body; the cylinder head includes a cylinder head body, and an intake cavity and an exhaust cavity are provided inside the cylinder head body and are isolated from each other. The air outlet is communicated with the intake cavity, and a plurality of second heat dissipation fins are provided outside the cylinder head body; a valve plate assembly is provided between the cylinder and the cylinder head. The valve plate assembly at least includes a valve plate, and at least the following are provided on the valve plate:

[0021] Intake through holes, which respectively communicate the air outlet and the intake cavity,

[0022] Suction through holes, which respectively communicate the intake cavity and the piston chamber, and the suction through holes are configured with suction valve plates;

[0023] Exhaust through holes, which respectively connect the piston chamber and the exhaust cavity, and the exhaust through holes are configured with exhaust valve plates.

[0024] A preferred embodiment, wherein an exhaust joint is provided on one side of the piston body, an exhaust hole communicating with the exhaust passage is provided on the piston body from the upper end surface of the piston body, and an exhaust valve hole communicating with the exhaust cavity and the exhaust hole is provided on the valve plate.

[0025] A preferred embodiment, wherein the exhaust through holes and the suction through holes are staggered in the radial direction of the valve plate, the exhaust through holes are closer to the center of the valve plate than the suction through holes, the suction valve plate is arranged on the side of the valve plate facing the piston chamber, the exhaust valve plate is arranged on the side of the valve plate facing the cylinder head, and an avoidance through groove for communicating the exhaust through hole and the piston chamber is provided on the suction valve plate.

[0026] The oil-free air compressor for vehicles in this embodiment has the following beneficial effects compared with the prior art:

[0027] (1) The drive shaft is the output shaft of the motor. That is, the output shaft of the motor and the drive shaft of the air compressor are of an integral structure. Compared with the prior art method of connecting the motor output shaft and the drive shaft with a coupling, defects such as vibration and noise caused by the coupling are eliminated, and its transmission stability is better and the transmission accuracy is higher.

[0028] (2) The crankshaft and the drive shaft are connected by a threaded connection. Compared with the key connection in the prior art, the assembly accuracy is higher, and at the same time, defects such as vibration and noise caused by the key connection are eliminated.

[0029] (3) In the case of multiple air compression devices, the adjacent crankshafts are directly fixedly connected. Since the crankshaft close to the motor side is directly threadedly connected to the drive shaft, and the remaining secondary crankshafts are all fixedly connected to this crankshaft based on this crankshaft, the formed crankshaft assembly also has the technical advantages of low vibration and low noise.

[0030] (4) The air compression devices are arranged in a V shape, saving the installation space and making the design layout of the whole vehicle more reasonable.

[0031] (5) The crankshaft connection end of the connecting rod is connected to the crankshaft through a rolling bearing, and the piston connection end is connected to the piston pin through a needle bearing. Since there are frame-type rubber sealing rings on both sides of the rolling bearing, lubricating grease can be stored in the sealed cavity; there are sealing oil seals on both sides of the needle bearing, and lubricating grease can be stored in the sealed cavity formed by the sealing oil seals; that is, both the needle bearing and the rolling bearing can be lubricated by the stored lubricating grease without additional lubricating oil. In addition, the piston realizes sliding sealing with the piston cavity through a sealing ring and a guide ring made of a self-lubricating wear-resistant composite material, and the self-lubricating wear-resistant composite material has the characteristic of self-lubrication and also does not require lubricating oil for lubrication.

[0032] Therefore, the oil-free air compressor for vehicles in this embodiment does not need to be equipped with an oil cooling system, has a simpler structure, lower cost, and avoids system failures caused by lubricating oil being discharged with the compressed air, and has better reliability.

[0033] (6) An intake chamber surrounding the piston cavity is provided inside the cylinder body. Before the gas is compressed, it has to pass through the intake chamber inside the cylinder body first. The gas passing through this intake chamber conducts an effective cooling process on the cylinder, and then combined with the heat dissipation of the heat dissipation fins I outside the cylinder body, the internal cooling and external heat dissipation combination method can effectively reduce the working temperature of the cylinder, thereby improving the continuous working time and working life of the air compression device and the oil-free air compressor for vehicles.

[0034] (7) The interior of the cylinder head is provided with an intake cavity communicating with the intake chamber, that is, the air needs to pass through the intake cavity inside the cylinder head before being compressed. The gas passing through the intake cavity also has a cooling effect on the cylinder head and the valve plate assembly. Combining with the external heat dissipation fins II, the cooling and heat dissipation method of combining internal cooling with external heat dissipation can also effectively reduce the working temperature of the cylinder head, thereby increasing the continuous working time and working life of the air compression device and the oil-free air compressor for vehicles.

[0035] (8) The valve plate assembly is independently arranged between the cylinder head and the cylinder, and has both the functions of air intake and exhaust. Compared with the structural form in the prior art where the air intake assembly and the exhaust assembly are separately arranged, the structure is simpler, more compact, the production cost is lower, the assembly efficiency is higher, and due to the concentration of functions, it is more convenient for replacement and maintenance. Description of the Drawings

[0036] Figure 1 is the external structure schematic diagram of the oil-free air compressor for vehicles in this embodiment;

[0037] Figure 2 is Figure 1 the external structure schematic diagram of the oil-free air compressor for vehicles shown after hiding the fan cover;

[0038] Figure 3 is Figure 1 the external structure schematic diagram of the oil-free air compressor for vehicles shown from another angle;

[0039] Figure 4 is the side view structure schematic diagram of the oil-free air compressor for vehicles in this embodiment;

[0040] Figure 5 is Figure 4 the A-A sectional view structure schematic diagram shown;

[0041] Figure 6 is the connection state structure schematic diagram of the motor and the crankshaft assembly in this embodiment;

[0042] Figure 7 is the exploded state structure schematic diagram of the motor and the crankshaft assembly in this embodiment;

[0043] Figure 8 is the structure schematic diagram of the crankshaft assembly in this embodiment;

[0044] Figure 9 is the exploded state structure schematic diagram of the crankshaft assembly in this embodiment;

[0045] Figure 10 is the structure schematic diagram of the crankshaft in this embodiment;

[0046] Figure 11 is the structure schematic diagram of the sub-crankshaft in this embodiment;

[0047] Figure 12 It is a schematic diagram of the external structure of the air compression device in this embodiment;

[0048] Figure 13 is Figure 12 A partial sectional structure schematic diagram of the air compression device shown;

[0049] Figure 14 is Figure 12 A schematic diagram of the external structure of the air compression device shown with the cylinder head hidden;

[0050] Figure 15 It is a schematic diagram of the external structure of the cylinder in the upward view state of this embodiment;

[0051] Figure 16 It is a schematic diagram of the external structure of the cylinder in the downward view state of this embodiment;

[0052] Figure 17 It is a sectional view of the cylinder in this embodiment;

[0053] Figure 18 It is a schematic diagram of the structure of the cylinder head in the upward view state of this embodiment;

[0054] Figure 19 It is a schematic diagram of the structure of the valve plate assembly in the upward view state of this embodiment;

[0055] Figure 20 It is a schematic diagram of the structure of the valve plate assembly in the downward view state of this embodiment;

[0056] Figure 21 It is a sectional view of the valve plate assembly in this embodiment;

[0057] Figure 22 It is a schematic diagram of the structure of the valve plate in this embodiment;

[0058] Figure 23 It is a schematic diagram of the structure of the suction valve plate in this embodiment;

[0059] Figure 24 It is a schematic diagram of the structure of the backing plate in this embodiment.

[0060] Figure 25 It is a front structure schematic diagram of the connection state of the crankshaft, connecting rod and piston in this embodiment;

[0061] Figure 26 is Figure 25 A sectional view of the schematic diagram of the connection state structure of the crankshaft, connecting rod and piston shown;

[0062] Figure 27 is Figure 25 A rear structure schematic diagram of the connection state of the crankshaft, connecting rod and piston shown. Detailed Implementation Manner

[0063] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0064] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0065] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, an integral connection, or a detachable connection; it can be the communication inside two elements; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0066] As Figures 1 - 5 shown, an oil-free air compressor for a vehicle in this embodiment includes a motor 100, a crankcase 200, two air compression devices 300 arranged in a V shape on the main shaft box, and a heat dissipation system 400 arranged on the side of the crankcase away from the motor. One end of the crankcase 200 is fixedly connected to the motor, and the other end is fixedly connected with a crankcase cover 210.

[0067] In this embodiment, the two air compression devices 300 are arranged in a V shape, with a compact structure, saving installation space and making the design layout of the whole vehicle more reasonable. The heat dissipation system 400 is arranged on the opposite side of the motor, and its layout is also more reasonable, making the overall occupied space of the device smaller, and the fan cover structure for guiding the heat dissipation air to the air compression device is simpler.

[0068] The air compression device 300 of this embodiment, as Figures 12 - 15 shown, includes a cylinder 310, a cylinder head 320, a piston 30, a connecting rod 20, and a valve plate assembly 330. The cylinder 310 includes a cylinder body 311 and a piston cavity 312 axially penetrating the cylinder body 311. The piston 30 is slidably and sealingly connected to the piston cavity 312 and reciprocates in the piston cavity. One end of the connecting rod 20 is movably connected to the piston 30, and the other end is connected to the crankshaft of the air compressor to provide the driving force for the reciprocating movement of the piston. The valve plate assembly 330 is fixedly connected between the cylinder head and the cylinder.

[0069] The air cylinder 310 of this embodiment, as Figures 15 - 17 shown, an air inlet chamber 313 surrounding the piston chamber 312 is provided inside the air cylinder body 311. The central angle of the air inlet chamber surrounding the piston chamber is between 90° and 360°. In this embodiment, preferably, the central angle is between 180° and 270°. The air inlet chamber 313 is open on the lower end surface of the piston body 311, and an air outlet 314 is provided on the upper end surface of the piston body.

[0070] Wherein, a plurality of first heat dissipation fins 318 are provided outside the air cylinder body 311 of this embodiment for heat dissipation.

[0071] In this embodiment, an exhaust joint 316 is provided on one side of the piston body 311. The exhaust joint 316 has an exhaust passage 317. At the same time, the piston body is also provided with an exhaust hole 315 communicating with the exhaust passage from the upper end surface of the piston body.

[0072] As Figure 18 shown, the cylinder head 320 of this embodiment includes a cylinder head body 321. An air inlet chamber 322 and an exhaust chamber 323 that are isolated from each other are provided inside the cylinder head body 321, and a partition plate 324 is provided between the air inlet chamber 322 and the exhaust chamber 323. Among them, the air inlet chamber 322 communicates with the air outlet 314 of the air inlet chamber 313. A plurality of second heat dissipation fins 325 are provided outside the cylinder head body 321 for heat dissipation. The exhaust chamber 323 communicates with the exhaust hole 315 on the piston body.

[0073] As Figures 19 - 21 shown, the valve plate assembly 330 of this embodiment has Figure 22 the valve plate 331 as shown. An air inlet through hole 3311, an air suction through hole 3313, an exhaust through hole 3314, and an exhaust valve hole 3312 are provided on the valve plate 331. Among them, the air inlet through hole 3311 communicates with the air outlet 314 and the air inlet chamber 322 respectively, and is used to provide an air flow channel for air to enter the air inlet chamber from the air inlet chamber. The air inlet through hole is preferably an arc-shaped hole.

[0074] In this embodiment, there are two air suction through holes 3313, which are arranged around the center of the valve plate 331 and are preferably arc-shaped holes. Among them, the two air suction through holes 3313 communicate with the air inlet chamber 322 and the piston chamber 312 respectively, and are used to provide an air flow channel for air to enter the piston chamber from the air inlet chamber during suction.

[0075] In this embodiment, there are three exhaust through holes 3314, which are arranged around the center of the valve plate 331 and are preferably arc-shaped holes. Among them, the three exhaust through holes 3314 are respectively connected to the piston chamber 312 and the exhaust chamber 323, and are used to discharge the compressed air in the piston chamber into the exhaust chamber.

[0076] Preferably, the exhaust through - holes 3314 and the intake through - holes 3313 are staggered in the radial direction of the valve plate, and the exhaust through - holes are closer to the center of the valve plate than the intake through - holes.

[0077] In this embodiment, the exhaust valve holes 3312 are respectively communicated with the exhaust cavity and the exhaust holes, and are used to discharge the compressed air in the exhaust cavity from the exhaust passage through the exhaust valve holes.

[0078] As Figure 21 As shown, in this embodiment, an exhaust valve sheet 333 is disposed on the side of the valve plate 331 facing the cylinder head. The center of the exhaust valve sheet 333 is fixedly connected to the valve plate, and the edge position covers the exhaust through - holes. The exhaust valve sheet has a certain elasticity. An intake valve sheet 332 is disposed on the side of the valve plate 331 facing the cylinder. The center of the intake valve sheet is fixedly connected to the valve plate, and the edge position covers the intake through - holes. The intake valve sheet has a certain elasticity.

[0079] Preferably, in this embodiment, the intake valve sheet 332 and the exhaust valve sheet 333 are fixedly connected to the valve plate 331 by bolts 336 and nuts 337. In this embodiment, the nut 337 is located on the side of the exhaust valve sheet.

[0080] Preferably, in this embodiment, a guide plate 334 is further provided between the exhaust valve sheet 333 and the nut 337. One side of the guide plate 334 facing the exhaust valve sheet 333 is a guiding surface, and the distance from the guiding surface to the valve plate gradually increases from the center to the edge. The function of the guiding surface is to control the deformation formation of the exhaust valve sheet during the exhaust process, and prevent the exhaust valve sheet from being unable to return to its original state due to excessive deformation.

[0081] Preferably, in this embodiment, a lining 335 is provided between the intake valve sheet 332 and the nut of the bolt to ensure that the center of the intake valve sheet 332 can be closely attached to the valve plate.

[0082] An intake valve sheet of this embodiment is as Figure 23 As shown, it includes an outer edge 3321 for covering the intake through - holes and a central fixing part 3323. A through - hole 3324 for the bolt to pass through is provided on the central fixing part 3323. Based on the characteristic that the intake through - holes and the exhaust through - holes of this embodiment are staggered in the radial direction, an avoidance through - groove 3322 for communicating the exhaust through - holes and the piston cavity is provided between the outer edge 3321 and the central fixing part 3323.

[0083] As Figure 24 As shown, a backing plate 338 is further provided between the cylinder head and the valve plate assembly of this embodiment. The backing plate 338 is provided with a separating strip 3383 adapted to the separator plate. Based on the separation of the separating strip, an intake groove 3382 and an exhaust groove 3381 adapted to the intake cavity and the exhaust cavity are provided. For the consideration of the structural strength and the degree of deformation, a number of connecting strips 3384 are further provided in the intake groove 3382.

[0084] The piston 30 of this embodiment, as Figures 25 - 27 shown, at least includes a piston body 31. An axially extending connecting rod connection cavity 38 and a radially extending pin hole 32 are provided inside the piston body 31. A piston pin 39 is installed in the pin hole. Preferably, the pin hole penetrates the piston body radially to facilitate the insertion of the piston pin for connection.

[0085] A sealing ring groove 33 and a guide ring groove 34 are provided outside the piston body of this embodiment. A sealing ring 36 is installed in the sealing ring groove 33, and this sealing ring is used to achieve sliding sealing between the piston and the piston cavity. Preferably, in order to ensure the sealing performance and the compensation after the wear of the sealing ring, a lining spring 37 is provided between the inner ring of the sealing ring and the sealing ring groove. This lining spring 37 always provides an elastic force for the sealing ring to radially extend. After the sealing ring wears, the worn amount can also be compensated to improve the service life.

[0086] In this embodiment, a guide ring 35 is installed in the guide ring groove 34. The guide ring and the sealing ring together form a support to ensure the displacement direction of the piston relative to the piston cavity and prevent eccentric wear.

[0087] It should be noted that in this embodiment, both the sealing ring and the guide ring are made of self-lubricating and wear-resistant composite materials. The self-lubricating and wear-resistant composite material itself is not the inventive point of this application, and this type of material can be purchased in the market, such as polytetrafluoroethylene-based self-lubricating and wear-resistant composite materials.

[0088] As Figures 25 - 27 shown, the crankshaft 10 of this embodiment at least includes a connecting rod connection neck 11. The connecting rod 20 of this embodiment includes a crankshaft connection end 21 and a piston connection end 22. The piston connection end 22 is connected to the piston pin 39 through a needle roller bearing 25. Sealing oil seals 26 are installed on both sides of the needle roller bearing. A sealed cavity is formed between the two sealing oil seals 26 for storing grease, and this grease will not leak into the compressor.

[0089] Furthermore, the crankshaft connection end 21 of this embodiment is connected to the connecting rod connection neck 11 through a rolling bearing 23. Skeleton rubber sealing rings 24 are installed between the inner and outer rings on both sides of the rolling bearing. A sealed cavity is also formed between the skeleton rubber sealing ring 24 and the inner and outer rings of the rolling bearing for storing grease, and this grease will not leak into the compressor. Preferably, the rolling bearing 23 is a deep groove ball bearing.

[0090] In an optional embodiment, in order to save costs and reduce weight, under the condition of meeting the connection strength, a weight-reducing hole 27 is provided on the connecting rod.

[0091] The principle of the air compression device in this embodiment is that the crankshaft drives the piston to reciprocate in the piston chamber. During the intake process, when the piston moves downward in the piston chamber, air enters the intake chamber of the cylinder head from the intake chamber of the cylinder through the intake through-hole of the valve plate assembly. At this time, the intake valve disc is in the open state under the action of air pressure, and the exhaust valve disc is in the closed state. The gas in the intake chamber enters the piston chamber through the intake through-hole of the valve plate assembly. During the compression process, the piston moves upward in the piston chamber. At this time, the exhaust valve disc is in the open state, and the intake valve disc is in the closed state. The compressed air in the piston chamber enters the exhaust chamber through the exhaust through-hole and is discharged through the exhaust joint.

[0092] As an improvement of this embodiment, as Figure 6 , Figure 7 shown, the output shaft of the motor and the drive shaft 110 are of an integral structure, and a connecting external thread 111 is provided at a position on the drive shaft 110 close to the motor 100. Correspondingly, as Figure 7 , Figure 10 shown, a connecting internal thread 13 adapted to the connecting external thread 111 is provided on one side of the rotary shaft hole 12 of the crankshaft 10 of this embodiment close to the drive motor 100. When the drive shaft is in a rotating state, there is a tendency for the connecting external thread and the connecting internal thread to be screwed tightly relative to each other. That is, when the compressor is working normally, the rotation of the drive shaft will not cause the connecting external thread and the connecting internal thread to become loose from the threaded connection, and there will be a tendency to become tighter and tighter.

[0093] As Figures 1 - 4 shown, when there are two or more air compression devices, the crankshafts corresponding to the multiple air compression devices form a crankshaft assembly, and this crankshaft assembly is driven by a drive shaft.

[0094] In this embodiment, taking two air compression devices as an example, its crankshaft assembly includes a crankshaft 10 on one side close to the motor 100 and a sub-crankshaft 10' provided on the side of the crankshaft 10 away from the motor 100. The sub-crankshaft 10' is also provided with a connecting rod connecting neck 11 and a rotary shaft hole 12, and the crankshaft 10 and the sub-crankshaft 10' are fixedly connected.

[0095] As a preferred implementation manner of this embodiment, as Figures 7 - 11 shown, a threaded connection hole 14 is provided on the crankshaft 10 of this embodiment, and a clearance hole 15 adapted to the threaded connection hole 14 is provided on the sub-crankshaft 10'. A connecting bolt 16 passes through the clearance hole 15 and is threadedly connected to the threaded connection hole 14 to achieve the fixed connection between the crankshaft 10 and the sub-crankshaft 10'. The threaded connection method has the technical advantages of simple structure, low cost and high assembly efficiency.

[0096] The heat dissipation system 400 of this embodiment, as Figure 2 , Figure 3 ,Figure 5 As shown, it includes a cooling fan 410 and a fan cover 430. The fan cover 430 is provided with an air cavity 431 for accommodating the cooling fan and guiding the cooling air, and the fan cover 430 is provided with guiding covers 433 whose positions and quantities correspond one-to-one with the air compression devices, and an air inlet grid 432 is provided on the fan cover 430.

[0097] As an improvement of this embodiment, the cooling fan 410 is directly fixedly connected to the drive shaft 110, and the drive shaft 110 drives the cooling fan 410 to rotate. In this way, the cooling system does not require an independent drive source, has a more concise structure, lower cost, saves energy consumption, and can also ensure synchronous cooling during the operation of the compressor.

[0098] A preferred embodiment is as Figure 6 、 Figure 7 shown. The free end of the drive shaft is provided with a cooling end connection thread 112. Correspondingly, as Figure 2 、 Figure 5 shown, the cooling fan 410 is further configured with a connection sleeve 420. The cooling fan is fixedly connected to the drive shaft through a threaded connection between the connection sleeve 420 and the cooling end connection thread 112. And when the drive shaft is in a rotating state, there is a tendency for the connection sleeve 420 and the cooling end connection thread 112 to be screwed tightly relative to each other.

[0099] As Figures 1 - 3 shown, in this embodiment, an air inlet joint 220 is provided on the crankcase 200, and this air inlet joint is used to connect to an air inlet gas source. The exhaust joints 316 of each cylinder are connected to an exhaust pipe 230, and the compressed air is discharged from the air compressor through this exhaust pipe. It should be noted that, as a preference, in this embodiment, this exhaust pipe passes through the fan cover 430 of the cooling system, so that the exhaust pipe can be effectively cooled.

[0100] In summary, the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. An oil-free air compressor for vehicles, comprising at least a motor (100), a crankcase (200), and at least one air compression device (300) provided on the crankcase. One end of the crankcase (200) is fixedly connected to the motor, and a crankcase cover (210) is connected to the end of the crankcase away from the motor; The air compression device at least includes: A cylinder (310), the cylinder includes a cylinder body (311) and a piston chamber (312) axially penetrating the cylinder body. One end of the cylinder body is fixedly connected to the crankcase, and the piston chamber communicates with the inner cavity of the crankcase; A piston (30), the piston is adapted to the piston chamber and is slidably and sealingly connected to the piston chamber; A connecting rod (20), the connecting rod is provided with a crankshaft connection end (21) and a piston connection end (22), and the piston connection end (22) is movably connected to the piston; A crankshaft (10), the crankshaft is provided with a connecting rod connection neck (11), the connecting rod connection neck (11) is movably connected to the crankshaft connection end (21), and the crankshaft is provided with a rotating shaft hole (12); A drive shaft (110), adapted to the rotating shaft hole. The drive shaft is the output shaft of the motor. A connecting external thread (111) is provided at a position on the drive shaft close to the motor. A connecting internal thread (13) adapted to the connecting external thread is provided on the side of the rotating shaft hole of the crankshaft close to the drive motor. When the drive shaft is in a rotating state, there is a tendency for the connecting external thread and the connecting internal thread to be screwed together relatively; It is characterized in that An intake chamber (313) surrounding the piston chamber is provided inside the cylinder body. The intake chamber is open on the lower end surface of the piston body, and an air outlet (314) is provided on the upper end surface of the piston body. The air outlet communicates with the intake chamber; A valve plate assembly is provided between the cylinder and the cylinder head. The valve plate assembly at least includes a valve plate, and the valve plate is at least provided with: Intake through holes (3311), the intake through holes respectively communicate the air outlet and the intake chamber, Suction through holes (3313), the suction through holes respectively communicate the intake chamber and the piston chamber, and the suction through holes are provided with suction valve plates; Exhaust through holes (3314), the exhaust through holes are respectively connected to the piston chamber and the exhaust chamber, and the exhaust through holes are provided with exhaust valve plates; It further includes a heat dissipation system (400). The heat dissipation system is arranged on the side of the crankcase away from the motor. The heat dissipation system at least includes a heat dissipation fan (410) and a fan cover (430). The fan cover is provided with an air cavity (431) for accommodating the heat dissipation fan and guiding the heat dissipation air. The fan cover is provided with guiding covers (433) corresponding to the air compression devices in position and quantity. The heat dissipation fan is fixedly connected to the drive shaft; The free end of the drive shaft is provided with a heat dissipation end connection thread (112), and the heat dissipation fan is further configured with a connection sleeve (420). The heat dissipation fan is fixedly connected to the drive shaft through a threaded connection between the connection sleeve (420) and the heat dissipation end connection thread (112). When the drive shaft is in a rotating state, there is a tendency for the connection sleeve (420) and the heat dissipation end connection thread (112) to be screwed tightly relative to each other; At least two air compression devices are provided on the crankcase. The two air compression devices are correspondingly connected to the drive shaft of the crankshaft assembly. The crankshaft assembly includes a crankshaft (10) on the side close to the motor and a sub-crankshaft (10') provided on the side of the crankshaft away from the motor. The sub-crankshaft (10') is provided with a connecting rod connection neck (11) and a rotating shaft hole (12). The crankshaft (10) and the sub-crankshaft (10') are fixedly connected.

2. The oil-free air compressor for vehicles according to claim 1, characterized in that, two air compression devices are provided on the crankcase, and the two air compression devices are arranged in a V shape.

3. The oil-free air compressor for vehicles according to claim 2, characterized in that, a threaded connection hole (14) is provided on the crankshaft (10), a light hole (15) adapted to the threaded connection hole (14) is provided on the sub-crankshaft (10'), the crankshaft (10) and the sub-crankshaft (10') are fixedly connected by a connecting bolt (16), and the threaded section of the connecting bolt (16) passes through the light hole (15) and is threadedly connected to the threaded connection hole (14).

4. The oil-free air compressor for vehicles according to any one of claims 1-3, characterized in that, the crankshaft connection end (21) and the connecting rod connection neck (11) are connected by a rolling bearing (23), and a skeleton rubber seal ring (24) is installed between the inner and outer rings on both sides of the rolling bearing; the piston at least includes a piston body (31), an axially extending connecting rod connection cavity (38) and a radially extending pin hole (32) are provided inside the piston body, a piston pin (39) is installed in the pin hole, the piston connection end (22) and the piston pin (39) are connected by a needle bearing (25), and seal oil seals (26) are installed on both sides of the needle bearing; a seal ring groove (33) and a guide ring groove (34) are provided outside the piston body, a seal ring (36) is installed in the seal ring groove (33), a guide ring (35) is installed in the guide ring groove (34), and both the seal ring and the guide ring are made of a self-lubricating and wear-resistant composite material.

5. The oil-free air compressor for vehicles according to claim 4, characterized in that, an exhaust joint (316) is provided on one side of the piston body, an exhaust hole (315) communicating with the exhaust passage (317) is provided on the piston body from the upper end surface of the piston body, and an exhaust valve hole (3312) communicating with the exhaust cavity and the exhaust hole is provided on the valve plate.

6. The oil-free air compressor for vehicles according to claim 5, characterized in that, The exhaust through-holes and the intake through-holes are arranged staggeredly in the radial direction of the valve plate. The exhaust through-holes are closer to the center of the valve plate than the intake through-holes. The intake valve plate is disposed on the side of the valve plate facing the piston chamber, and the exhaust valve plate is disposed on the side of the valve plate facing the cylinder head. An avoidance through-groove for communicating the exhaust through-hole and the piston chamber is provided on the intake valve plate.

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