Oil-free air compressor and vehicle

Abstract

The present invention relates to the technical field of new energy vehicles, and specifically relates to an oil-free air compressor and a vehicle. An oil-free air compressor, comprising a cylinder body, which is internally provided with a primary compression chamber, a primary exhaust chamber and a high-pressure chamber; wherein the primary compression chamber and the primary exhaust chamber are coaxially arranged and are respectively parallel to the axis of the high-pressure chamber; the sum of the axial length of the primary compression chamber and the axial length of the primary exhaust chamber is less than the axial length of the high-pressure chamber; further comprising a first valve plate assembly, which is arranged between the primary compression chamber and the primary exhaust chamber; the first valve plate assembly is provided with a first check valve body, which is used to allow unidirectional flow from the primary compression chamber to the primary exhaust chamber. Compared with the prior art, the present invention shortens the stroke of the low-pressure piston assembly inside the primary compression chamber by reducing the axial length of the primary compression chamber (low-pressure chamber) and the axial length of the low-pressure piston connecting rod assembly. Therefore, the present invention solves the technical problem existing in the prior art: how to shorten the axial stroke of the low-pressure piston assembly.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of new energy vehicles, and specifically relates to an oil-free air compressor and a vehicle.BACKGROUND ART

[0002] Piston-type oil-free air compressors are used for air compression in new energy vehicles. Reference document CN201822042980.8 discloses the structure of an electrically driven oil-free air compressor used in new energy vehicles. This oil-free air compressor comprises a cylinder body, which is internally provided with a low-pressure chamber. A low-pressure piston assembly is arranged within the low-pressure chamber. The low-pressure piston assembly moves reciprocally inside the low-pressure chamber, thereby compressing the air entering the low-pressure chamber.

[0003] Usually, the axial stroke of the low-pressure piston assembly inside the low-pressure chamber directly affects the surface treatment area of the inner wall of the low-pressure chamber, thereby affecting the processing cost of the piston cylinder.

[0004] Specifically, in the prior art, the low-pressure piston assembly needs to move from the lowest point of the low-pressure chamber to the highest point of the low-pressure chamber to complete one air compression process. That is, the axial stroke of the low-pressure piston assembly inside the low-pressure chamber is equal to the axial length of the low-pressure chamber. This leads to, under the condition that the diameter of the low-pressure chamber is determined, the length of the low-pressure chamber that contacts and slides with the low-pressure piston assembly being the entire axial length of the low-pressure chamber. If the diameter of the low-pressure chamber is D and the entire axial length of the low-pressure chamber is L, then the area of the inner wall of the low-pressure chamber that needs surface treatment equals πDL. The surface treatment refers to using specific process so as to improve the wear resistance, temperature resistance, corrosion resistance of that part of the inner wall of the low-pressure chamber, and to reduce the friction coefficient. Therefore, the larger the surface treatment area of the inner wall of the low-pressure chamber, the higher the processing cost of the piston cylinder.

[0005] In summary, in order to reduce the processing cost of the piston cylinder, the surface treatment area of the inner wall of the low-pressure chamber needs to be reduced. Ultimately, the axial stroke of the low-pressure piston assembly inside the low-pressure chamber needs to be reduced.

[0006] Therefore, the technical problem existing in the prior art is how to shorten the axial stroke of the low-pressure piston assembly.SUMMARY

[0007] In view of the technical problem in the prior art of how to shorten the axial stroke of the low-pressure piston assembly, the present invention provides an oil-free air compressor and a vehicle.

[0008] The present invention is achieved through the following technical solution:

[0009] An oil-free air compressor, comprising a cylinder body, which is internally provided with a primary compression chamber, a primary exhaust chamber and a high-pressure chamber;

[0010] wherein the primary compression chamber and the primary exhaust chamber are coaxially arranged and are respectively parallel to the axis of the high-pressure chamber; the sum of the axial length of the primary compression chamber and the axial length of the primary exhaust chamber is less than the axial length of the high-pressure chamber;

[0011] further comprising a first valve plate assembly, which is arranged between the primary compression chamber and the primary exhaust chamber; the first valve plate assembly is provided with a first check valve body, which is used to allow unidirectional flow from the primary compression chamber to the primary exhaust chamber;

[0012] further comprising a box body, which is located below the cylinder body and is connected to the cylinder body;

[0013] further comprising a crankshaft assembly, a low-pressure connecting rod and a low-pressure piston assembly; the crankshaft assembly is arranged inside the box body, and the primary compression chamber is located between the primary exhaust chamber and the crankshaft assembly; the low-pressure piston assembly is movably arranged inside the primary compression chamber and is connected to the crankshaft assembly through the low-pressure connecting rod;

[0014] further comprising a high-pressure connecting rod and a high-pressure piston assembly; the high-pressure piston assembly is movably arranged inside the high-pressure chamber and is connected to the crankshaft assembly through the high-pressure connecting rod;

[0015] the direction from the primary compression chamber pointing to the primary exhaust chamber is defined as upward, and the opposite direction is defined as downward, along the axial direction of the primary compression chamber and the primary exhaust chamber;

[0016] the top dead center of the high-pressure piston assembly is located above the first valve plate assembly, and the top dead center of the motion of the low-pressure piston assembly is located below the first valve plate assembly.

[0017] Further, the oil-free air compressor comprises an intercooler valve plate and a cylinder head; the combination of the intercooler valve plate and the cylinder head covers the cylinder body, and the intercooler valve plate is located between the cylinder head and the cylinder body;

[0018] the cylinder head and the intercooler valve plate jointly define a secondary exhaust chamber; the intercooler valve plate is provided with a second check valve body, which may allow unidirectional flow from the high-pressure chamber to the secondary exhaust chamber;

[0019] the secondary exhaust chamber is further provided with a noise reduction rib, which extends along the axial direction of the primary compression chamber; one end of the noise reduction rib is connected to the inner wall of the secondary exhaust chamber, and the other end is not in contact with any inner wall of the secondary exhaust chamber.

[0020] Further, the number of the noise reduction ribs is multiple, and the multiple noise reduction ribs are arranged parallel to each other at intervals.

[0021] Further, the oil-free air compressor comprises an intercooler, which is used to drive the external air of the oil-free air compressor to flow and form cooling air;

[0022] further comprising a first air blowing channel, which is used to deliver a portion of the cooling air;

[0023] a first air duct is provided inside the side wall of the cylinder body; the intercooler valve plate is provided with a second through hole; a second air duct is provided inside the cylinder head, and the second air duct forms a first air outlet on the surface of the cylinder head;

[0024] the first air duct, the second through hole, the second air duct and the first air outlet are respectively components of the first air blowing channel.

[0025] Further, the outer surface of the cylinder head is provided with a heat dissipation rib, and the first air outlet faces the heat dissipation rib.

[0026] Further, a second air blowing channel is provided; one end of the second air blowing channel is connected to the first air duct, and the other end intersects with the side wall of the cylinder head to form a second air outlet.

[0027] Further, the box body is provided with an opening;

[0028] further comprising a steel sleeve and a bearing; both the steel sleeve and the bearing are arranged inside the box body, and, the steel sleeve is located between the bearing and the box body along the radial direction of the bearing; the crankshaft assembly is rotatably connected to the steel sleeve through the bearing;

[0029] further comprising a connecting member and a foot pad; one end of the connecting member is connected to the steel sleeve, and the other end passes through the opening of the box body and is connected to the foot pad.

[0030] Further, the outer ring surface of the bearing is provided with a first engagement slot, and the steel sleeve is provided with a first engagement hole; further comprising an engagement member, one end of the engagement member is inserted into the first engagement hole, and the other end is engaged into the first engagement slot.

[0031] Further, the number of the openings, the number of the connecting members and the number of the foot pads are all the same.

[0032] A vehicle, which comprises the aforementioned oil-free air compressor.

[0033] Compared with the prior art, the advantages of the present invention are:

[0034] 1. In the present invention, the sum of the axial length of the primary compression chamber and the axial length of the primary exhaust chamber is less than the axial length of the high-pressure chamber, thereby making the axial length of the primary compression chamber (low-pressure chamber) in the present invention smaller than the axial length of the low-pressure chamber in the prior art. In the present invention, the top dead center of the high-pressure piston assembly is located above the first valve plate assembly, and the top dead center of the motion of the low-pressure piston assembly is located below the first valve plate assembly, thereby making the axial length of the low-pressure piston connecting rod assembly in the present invention smaller than that of the low-pressure piston connecting rod assembly in the prior art, to match the primary compression chamber in the present invention which has a smaller axial length compared to the prior art. In the present invention, the maximum axial stroke of the low-pressure piston assembly is the axial length of the primary compression chamber. Compared with the prior art, the present invention shortens the stroke of the low-pressure piston assembly inside the primary compression chamber by reducing the axial length of the primary compression chamber (low-pressure chamber) and the axial length of the low-pressure piston connecting rod assembly. Therefore, the present invention solves the technical problem existing in the prior art: how to shorten the axial stroke of the low-pressure piston assembly.DESCRIPTION OF DRAWINGS

[0035] FIG. 1 is a structural schematic view of the cylinder body in Example 1;

[0036] FIG. 2 is a structural schematic view of the first check valve body in FIG. 1;

[0037] FIG. 3 is a structural sectional view of the oil-free air compressor in Example 1;

[0038] FIG. 4 is a structural schematic view of the cylinder body from another perspective;

[0039] FIG. 5 is a structural schematic view of the intercooler valve plate of the present invention;

[0040] FIG. 6 is a partial sectional view of the cylinder end of the present invention;

[0041] FIG. 7 is a schematic view of the back side of the cylinder head of the present invention;

[0042] FIG. 8 is a structural schematic view of the steel sleeve of the present invention;

[0043] FIG. 9 is a structural schematic view of the bearing of the present invention.

[0044] Label in the drawings: cylinder body (1), first valve plate assembly (3), first unidirectional channel (301), primary compression chamber (4), primary exhaust chamber (5), first check valve body (6), fixed shaft (601), elastic sheet (602), low-pressure piston assembly (7), high-pressure chamber (8), high-pressure piston assembly (9), intercooler valve plate (10), cylinder head (11), secondary exhaust chamber (12), second check valve body (13), noise reduction rib (14), intercooler (15), first air duct (16), second through hole (17), second air duct (18), first air outlet (19), heat dissipation rib (20), second air blowing channel (22), crankshaft assembly (23), high-pressure connecting rod (24), low-pressure connecting rod (25), box body (26), opening (27), steel sleeve (28), bearing (29), connecting member (30), foot pad (31), first gas port (32), second gas port (33), first engagement slot (34), engagement member (35), heat conduction rib (36), primary intake valve sheet (37), motor (38), plum blossom elastic coupling (39), flywheel (40), crankshaft (41), counterweight (42), first engagement hole (43), dust collection groove (44).DETAILED DESCRIPTIONS

[0045] The following describes the technical solution of the invention in further non-limiting detail by combining preferred embodiments and their accompanying drawings. In the description of the present invention, it should be understood that the directions or positional relationships indicated by terms such as “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “up”, “down”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” are based on the directions or positional relationships shown in the drawings. Furthermore, terms “first”, “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical feature. Thus, features defined with “first”, “second” may explicitly or implicitly include at least one such feature. In the description of the present invention, “a plurality of” means at least two, such as two, three, etc., unless otherwise explicitly and specifically defined. The Examples described below with reference to the drawings are exemplary, intended to explain the present invention and should not be construed as limiting the present invention.Example 1

[0046] As shown in FIGS. 1 to 3, this Example proposes an oil-free air compressor, comprising a cylinder body 1, which is internally provided with a primary compression chamber 4, a primary exhaust chamber 5 and a high-pressure chamber 8; wherein the primary compression chamber 4 and the primary exhaust chamber 5 are coaxially arranged and are respectively parallel to the axis of the high-pressure chamber 8; the sum of the axial length of the primary compression chamber 4 and the axial length of the primary exhaust chamber 5 is less than the axial length of the high-pressure chamber 8; further comprising a first valve plate assembly 3, which is arranged between the primary compression chamber 4 and the primary exhaust chamber 5; the first valve plate assembly 3 is provided with a first check valve body 6, which is used to allow unidirectional flow from the primary compression chamber 4 to the primary exhaust chamber 5; further comprising a box body 26, which is located below the cylinder body 1 and is connected to the cylinder body 1; further comprising a crankshaft assembly 23, a low-pressure connecting rod 25 and a low-pressure piston assembly 7; the crankshaft assembly 23 is arranged inside the box body 26, and the primary compression chamber 4 is located between the primary exhaust chamber 5 and the crankshaft assembly 23; the low-pressure piston assembly 7 is movably arranged inside the primary compression chamber 4 and is connected to the crankshaft of the crankshaft assembly 23 through the low-pressure connecting rod 25; further comprising a high-pressure connecting rod 24 and a high-pressure piston assembly 9; the high-pressure piston assembly 9 is movably arranged inside the high-pressure chamber 8 and is connected to the crankshaft assembly 23 through the high-pressure connecting rod 24; the direction from the primary compression chamber 4 pointing to the primary exhaust chamber 5 is defined as upward, and the opposite direction is defined as downward, along the axial direction of the primary compression chamber 4 and the primary exhaust chamber 5; the top dead center of the high-pressure piston assembly 9 is located above the first valve plate assembly 3, and the top dead center of the motion of the low-pressure piston assembly 7 is located below the first valve plate assembly 3.

[0047] The cylinder body 1 is made of metal. The cylinder body 1 may be machined to form the primary compression chamber 4, the primary exhaust chamber 5 and the first valve plate assembly 3.

[0048] The first valve plate assembly 3 is provided with the first check valve body 6. The primary compression chamber 4 and the primary exhaust chamber 5 may be connected unidirectionally through the first check valve body 6. When gas flows, it flows unidirectionally from the primary compression chamber 4 to the primary exhaust chamber 5.

[0049] Combining FIGS. 1 to 3, specifically, the first valve plate assembly 3 is provided with a first unidirectional channel 301. One end of the first unidirectional channel 301 is connected to the primary compression chamber 4, and the other end is connected to the primary exhaust chamber 5. The first check valve body 6 comprises a fixed shaft 601 and an elastic sheet 602. The first unidirectional channel 301 corresponds to the edge of the elastic sheet 602 along the axial direction of the primary exhaust chamber 5. When gas is compressed inside the primary compression chamber 4 and the gas pressure reaches a certain value, the gas acts on the edge of the elastic sheet 602 through the first unidirectional channel 301, causing the edge of the elastic sheet 602 to lift away from the first valve plate assembly 3. The edge of the elastic sheet 602 does not block the first unidirectional channel 301, allowing the primary compression chamber 4 and the primary exhaust chamber 5 to be connected through the first unidirectional channel 301. In other situations, for example, when the gas pressure is insufficient to push the edge of the elastic sheet 602 to lift away from the first valve plate assembly 3, or when the low-pressure piston assembly 7 moves downward and a negative pressure is generated inside the primary compression chamber 4, the edge of the elastic sheet 602 swings towards the direction of the first valve plate assembly 3, and the edge of the elastic sheet 602 blocks the first unidirectional channel 301, cutting off the connection between the primary compression chamber 4 and the primary exhaust chamber 5.

[0050] The primary compression chamber 4 is also called the low-pressure chamber. The low-pressure piston assembly 7 is confined inside the primary compression chamber 4.

[0051] The high-pressure chamber 8 is also called the secondary compression chamber. The size and dimensions of the high-pressure chamber 8 are the same as those in the prior art. The processing method for the high-pressure chamber 8 has various options. For example, the high-pressure chamber 8 runs through the cylinder body 1 from top to bottom, forming a first port and a second port on the upper surface and lower surface of the cylinder body 1, respectively. The air that has been primarily compressed by the low-pressure piston assembly 7 in the primary compression chamber 4 continues to be delivered to the high-pressure chamber 8, i.e., the secondary compression chamber, to be secondarily compressed by the high-pressure piston assembly 9.

[0052] On the premise that the axial length of the high-pressure chamber 8 in this Example is equal to the axial length of the high-pressure chamber in the prior art, in the prior art, the axial length of the low-pressure chamber is consistent with the axial length of the high-pressure chamber; while in this Example, the sum of the axial length of the primary compression chamber 4 and the axial length of the primary exhaust chamber 5 is less than the axial length of the high-pressure chamber 8. Therefore, the axial length of the primary compression chamber 4, that is, the low-pressure chamber in this Example is smaller than the axial length of the high-pressure chamber 8. Thus, it may be deduced without any doubt that: the axial length of the primary compression chamber 4 (low-pressure chamber) in this Example is smaller than the axial length of the low-pressure chamber in the prior art.

[0053] The structures of the low-pressure piston assembly 7 and the high-pressure piston assembly 9 are the same as those in the prior art and will not be elaborated here.

[0054] In this Example, the combination of the low-pressure piston assembly 7 and the low-pressure connecting rod 25 is the low-pressure piston connecting rod assembly, and the combination of the high-pressure piston assembly 9 and the high-pressure connecting rod 24 was the high-pressure piston connecting rod assembly.

[0055] As mentioned above, this Example shortens the axial length of the primary compression chamber 4 (low-pressure chamber). If the low-pressure piston connecting rod assembly from the prior art were still used to connect to the crankshaft assembly, it would lead to insufficient axial space in the cylinder body. Therefore, in this Example, in order to match the primary compression chamber 4 which has a smaller axial length compared to the prior art, the axial length of the low-pressure piston connecting rod assembly is further shortened.

[0056] Specifically, this Example proposes that: the top dead center of the high-pressure piston assembly 9 is located above the first valve plate assembly 3, and the top dead center of the motion of the low-pressure piston assembly 7 is located below the first valve plate assembly 3. Both the high-pressure connecting rod 24 and the low-pressure connecting rod 25 are connected to the same crankshaft assembly 23, it can be concluded that:

[0057] On the premise that the axial length of the high-pressure piston connecting rod assembly in present invention is consistent with that of the high-pressure piston connecting rod assembly in the prior art; in the prior art, the axial length of the low-pressure piston connecting rod assembly is consistent with the axial length of the high-pressure piston connecting rod assembly. In this Example, since the top dead center of the high-pressure piston assembly 9 is located above the top dead center of the low-pressure piston assembly 7, that is, the top dead center of the high-pressure piston connecting rod assembly is located above the top dead center of the low-pressure piston connecting rod assembly, and since both the high-pressure piston connecting rod assembly and the low-pressure piston connecting rod assembly are connected to the same crankshaft assembly 23, therefore, the axial length of the low-pressure piston connecting rod assembly in this Example is smaller than that of the high-pressure piston connecting rod assembly. Thus, it can be deduced without any doubt that: the axial length of the low-pressure piston connecting rod assembly in this Example is smaller than that of the low-pressure piston connecting rod assembly in the prior art.

[0058] In summary, compared with the prior art, this Example not only shortens the axial length of the primary compression chamber 4 but also shortens the axial length of the low-pressure piston connecting rod assembly.

[0059] From the background technology, it is known that the technical problem existing in the prior art for this Example is how to shorten the axial stroke of the low-pressure piston assembly.

[0060] In this Example, the sum of the axial length of the primary compression chamber 4 and the axial length of the primary exhaust chamber 5 is less than the axial length of the high-pressure chamber 8, thereby making the axial length of the primary compression chamber 4 (low-pressure chamber) in this Example smaller than that of the low-pressure chamber in the prior art. In this Example, the top dead center of the high-pressure piston assembly 9 is located above the first valve plate assembly 3, and the top dead center of the motion of the low-pressure piston assembly 7 is located below the first valve plate assembly 3, thereby making the axial length of the low-pressure piston connecting rod assembly in this Example smaller than that of the low-pressure piston connecting rod assembly in the prior art, to match the primary compression chamber 4 in this Example which has a smaller axial length compared to the prior art. In this Example, the maximum axial stroke of the low-pressure piston assembly 7 is the axial length of the primary compression chamber 4. Compared with the prior art, this Example shortens the stroke of the low-pressure piston assembly 7 inside the primary compression chamber 4 by reducing the axial length of the primary compression chamber 4 (low-pressure chamber) and the axial length of the low-pressure piston connecting rod assembly. Therefore, this Example solves the technical problem existing in the prior art: how to shorten the axial stroke of the low-pressure piston assembly.

[0061] Furthermore, since this Example shortens the axial length of the primary compression chamber 4 (low-pressure chamber), under the condition that the diameter of the primary compression chamber 4 (low-pressure chamber) in this Example is consistent with the diameter of the low-pressure chamber in the prior art, the surface treatment area of the inner wall of the primary compression chamber 4 in this Example is smaller, saving processing costs.

[0062] Furthermore, in this Example, the low-pressure piston assembly 7 only moves within the primary compression chamber 4. The low-pressure piston assembly 7 has the characteristics of large diameter and heavy weight. Compared with the prior art, this Example has a lower top dead center for the motion of the low-pressure piston assembly 7, resulting in a lower center of gravity. Therefore, this leads to the oil-free air compressor using this Example having a lower center of gravity compared to the prior art. An oil-free air compressor with a lower center of gravity operates more stably.

[0063] The compressed air, abbreviated as compressed air, has significant energy due to being worked on multiple times. During the transmission process, the compressed air easily collides with the inner walls of the transmission channel, generating pulsation noise. Usually, the oil-free air compressor is arranged under the vehicle chassis, and the driver's cab is located above the oil-free air compressor. The pulsation noise from compressed air transmission will seriously affect the overall vehicle comfort and is difficult to meet the vehicle NVH requirements.

[0064] How to reduce the pulsation noise of compressed air is a technical problem that needs to be solved. This technical problem is solved by the following technical solution.

[0065] As shown in FIGS. 3 to 5, the oil-free air compressor of this Example further comprises an intercooler valve plate 10 and a cylinder head 11. The combination of the intercooler valve plate 10 and the cylinder head 11 covers the cylinder body 1, and the intercooler valve plate 10 is located between the cylinder head 11 and the cylinder body 1. The cylinder head 11 and the intercooler valve plate 10 jointly define a secondary exhaust chamber 12. The intercooler valve plate 10 is provided with a second check valve body 13, which may allow unidirectional flow from the high-pressure chamber 8 to the secondary exhaust chamber 12. The secondary exhaust chamber 12 is further provided with a noise reduction rib 14. The noise reduction rib 14 extends along the axial direction of the primary compression chamber 4. One end of the noise reduction rib 14 is connected to the inner wall of the secondary exhaust chamber 12, and the other end is not in contact with any inner wall of the secondary exhaust chamber 12.

[0066] The noise reduction rib 14 may be made of metal or other materials. Preferably, in this Example, the material of the noise reduction rib 14 is consistent with that of the cylinder head 11. The noise reduction rib 14 may be processed by machining, turning, or integrated casting. Preferably, the number of the noise reduction ribs 14 is multiple, and the multiple noise reduction ribs 14 are arranged parallel to each other at intervals.

[0067] The structure and principle of the second check valve body 13 are similar to those of the first check valve body 6 and will not be elaborated here. In this Example, gas flows unidirectionally in the order of primary compression chamber 4, primary exhaust chamber 5, high-pressure chamber 8, and secondary exhaust chamber 12.

[0068] The advantages of such solution are as follows:

[0069] Firstly, in this Example, due to the setting of the noise reduction ribs 14, during the process of compressed air passing through the secondary exhaust chamber 12, on one hand, the pulsation energy of the gas is absorbed by the noise reduction ribs 14 and conducted to the cylinder head 11; on the other hand, the pulsation energy of the gas is blocked and attenuated by the noise reduction ribs 14. This Example reduces the pulsation energy of the gas by setting the noise reduction ribs 14, thereby reducing the pulsation noise of the gas.

[0070] Secondly, in the prior art, the cylinder head needed to accommodate the spaces for both the primary exhaust chamber and the secondary exhaust chamber. In this Example, the primary exhaust chamber originally arranged in the cylinder head in the prior art is arranged in the cylinder body 1. It can be understood that, in this Example, the cylinder head 11 only needs to accommodate one chamber, that is, the secondary exhaust chamber 12. Therefore, this Example allows the secondary exhaust chamber 12 to occupy the internal space of the cylinder head 11 as much as possible, making the secondary exhaust chamber 12 in this Example larger in volume than the secondary exhaust chamber in the prior art. Furthermore, the noise reduction ribs 14 may be made relatively thin, making the cavity volume of the secondary exhaust chamber 12 larger. If the volume of the secondary exhaust chamber 12 in this Example is larger than that in the prior art, the gas with pulsation energy occupies a smaller proportion of the volume when entering the secondary exhaust chamber 12, resulting in smaller airflow fluctuations inside the secondary exhaust chamber 12, which further helps to reduce gas pulsation noise.

[0071] Thirdly, in this Example, the primary compression chamber 4, the primary exhaust chamber 5 and the secondary exhaust chamber 12 are arranged in a gradient from bottom to top, making the structure compact and rationally utilizing space. In addition, it may also serve the function of reducing mechanical noise. Specifically, the operating noise of the crankshaft assembly 23 inside the air compressor is mechanical noise. During the upward transmission of mechanical noise from bottom to top, it sequentially passes through the three chambers: the primary compression chamber 4, the primary exhaust chamber 5 and the secondary exhaust chamber 12, which are filled with air. This has a function of attenuating and reducing noise. The principle is: 1. air is a good sound-absorbing material that may absorb part of the noise energy, and when noise passes through the air to the chamber, the air damping effect between air molecules may gradually weaken the noise energy; 2. when noise is transmitted into the chamber, part of the noise may be absorbed by the wall material of the chamber, and the remaining noise may cause air vibration inside the chamber. This vibration may collide with the inner walls of the chamber and be blocked by them, thereby weakening the noise. Therefore, this Example may also reduce mechanical noise from bottom to top.

[0072] Fourthly, oil-free air compressors are usually arranged under the vehicle chassis, below the driver's cab. This Example reduces the gas pulsation noise and mechanical noise of the oil-free air compressor, further improving the comfort of the driver.

[0073] Further, the low-pressure piston assembly 7 has a primary intake valve sheet 37. The structure and setting method of the primary intake valve sheet 37 are both prior art. See the content disclosed in patent document CN201822042980.8.

[0074] Further, the oil-free air compressor of this Example further comprises a motor 38, a crankshaft assembly 23, a plum blossom elastic coupling 39 and a flywheel 40. The crankshaft assembly 23 comprises a crankshaft 41 and two counterweights 42. The crankshaft 41 is a two-piece combined and opposed structure. The two counterweights 42 are respectively arranged on both sides of the crankshaft 41. The motor 38 is arranged on one side of the crankshaft assembly 23. The counterweight 42 facing the motor 38 is connected to the main shaft of the motor 38 through the plum blossom elastic coupling 39 and the flywheel 40. Further, the high-pressure piston assembly 9 is connected to the crankshaft 41 through the high-pressure connecting rod 24, and the low-pressure piston assembly 7 is connected to the crankshaft 41 through the low-pressure connecting rod 25.

[0075] Further, as shown in FIG. 3, the oil-free air compressor further comprises an intercooler 15. The intercooler 15 comprises an intercooling channel and a fan for cooling the intercooling channel. The intercooling channel is used to deliver compressed air, and the two ends of the intercooling channel are a cooling inlet and a cooling outlet, respectively. The rotation of the fan drives the surrounding external air of the air compressor to form cooling air, which is used to cool the intercooling channel.

[0076] As shown in FIGS. 3 to 4, the cylinder body 1 of the oil-free air compressor in this Example is internally provided with a first connection channel and a second connection channel. One end of the first connection channel is connected to the cooling inlet of the intercooling channel, and the other end intersects with the upper surface of the cylinder body 1 to form a first gas port 32. One end of the second connection channel is connected to the cooling outlet of the intercooling channel, and the other end intersects with the upper surface of the cylinder body 1 to form a second gas port 33.

[0077] During use, the motor 38 provides the power source, and drives the crankshaft 41 to rotate through the flywheel 40 and the plum blossom elastic coupling 39, thereby achieving alternating reciprocal motion of the low-pressure piston assembly 7 and the high-pressure piston assembly 9, causing a periodic change in the volume of the primary compression chamber 4 and the high-pressure chamber 8 (secondary compression chamber) to achieve the purpose of compressing air.

[0078] When the low-pressure piston assembly 7 moves from top dead center to bottom dead center, a negative pressure is generated in the primary compression chamber 4, and gas is sucked into the primary compression chamber 4 through the primary intake valve sheet 37 of the low-pressure piston assembly 7. When the low-pressure piston assembly 7 moves from bottom dead center to top dead center, the gas in the primary compression chamber 4 is squeezed, the gas pressure increases, and the gas enters the primary exhaust chamber 5 through the first check valve body 6. At this point, the primary compression of the gas is completed. The gas at this time has lower pressure and higher temperature. Then, the gas passes through the first gas port 32, passes through the first connection channel, enters the intercooling channel and is cooled by the fan, and then is delivered to the second gas port 33 through the second connection channel.

[0079] Subsequently, when the high-pressure piston assembly 9 moves from top dead center to bottom dead center, a negative pressure is generated in the high-pressure chamber 8 (secondary compression chamber), and gas is sucked into the high-pressure chamber 8; when the high-pressure piston assembly 9 moves from bottom dead center to top dead center, the gas in the high-pressure chamber 8 is squeezed again, the gas pressure increases, and the gas enters the secondary exhaust chamber 12 through the second check valve body 13. At this point, the secondary compression of the gas is completed. As the pistons move reciprocally, the above process repeats, and gas is continuously compressed and discharged.

[0080] The combination of the cylinder body 1, the intercooler valve plate 10 and the cylinder head 11 forms the cylinder end. From the previous content, it is known that high-temperature compressed air may flow inside the cylinder end. How to cool the cylinder end is a technical problem that needs to be solved. This technical problem is solved by the following technical solution.

[0081] As shown in FIGS. 3 to 7, the oil-free air compressor of this Example further comprises a first air blowing channel, which is used to deliver a portion of the cooling air driven by the fan of the intercooler 15. A first air duct 16 is provided within the side wall of the cylinder body 1. The intercooler valve plate 10 is provided with a second through hole 17. A second air duct 18 is provided inside the cylinder head 11, and the second air duct 18 forms a first air outlet 19 on the surface of the cylinder head 11. The first air duct 16, the second through hole 17, the second air duct 18 and the first air outlet 19 are respectively components of the first air blowing channel.

[0082] During use, a portion of the cooling air driven by the fan of the intercooler 15 passes through the first air duct 16, the second through hole 17 and the second air duct 18 in sequence, and finally blows out from the first air outlet 19. The cooling air in the first air blowing channel carries away the heat within the channel during flow, including the heat from the inner wall of the first air duct 16 arranged in the cylinder body 1, the heat from the inner wall of the second through hole 17 arranged in the intercooler valve plate 10, and the heat from the inner wall of the second air duct 18 arranged in the cylinder head 11. This achieves the purpose of cooling the cylinder body 1, the intercooler valve plate 10 and the cylinder head 11 respectively, that is, cooling the cylinder end.

[0083] Preferably, several heat conduction ribs 36 are arranged inside the second through hole 17. The several heat conduction ribs 36 are arranged at intervals and are respectively connected to the hole wall of the second through hole 17. The purpose is to increase the contact area between the intercooler valve plate 10 and the cooling air, making the heat exchange efficiency between the intercooler valve plate 10 and the cooling air higher.

[0084] Further preferably, the outer surface of the cylinder head 11 is provided with heat dissipation ribs 20, and the first air outlet 19 faces the heat dissipation ribs 20. The cooling air blowing out from the first air outlet 19 continues to sweep towards the heat dissipation ribs 20 on the outer surface of the cylinder head 11, thereby carrying away the heat of the cylinder head 11 through the heat dissipation ribs 20. The setting of the heat dissipation ribs 20 increases the heat exchange efficiency between the cooling air and the cylinder head 11, serving the purpose of further cooling the surface of the cylinder head 11.

[0085] Further, as shown in FIGS. 3 to 4, the oil-free air compressor of this Example is further provided with a second air blowing channel 22. One end of the second air blowing channel 22 is connected to the first air duct 16, and the other end intersects with the side wall of the cylinder head 11 to form a second air outlet.

[0086] In this Example, a portion of the cooling air is diverted from the first air duct 16, and blows out from the second air outlet on the side wall of the cylinder head 11 through the second air blowing channel 22, to achieve the purpose of cooling the side wall of the cylinder head 11.

[0087] Further, in the prior art, the crankshaft assembly is directly connected to the air compressor box body through bearings. The downward force generated by the combined weight of the crankshaft assembly, the low-pressure piston assembly and the high-pressure piston assembly, as well as the torque from the motion of the high and low-pressure piston assemblies, are all transmitted to the air compressor box body. Usually, in order to meet the requirements of lightweighting for the entire machine, the air compressor box body is made of aluminum material. This leads to the deformation or fracture of the air compressor housing under the long-term action of the aforementioned forces and torques during long-term use. Therefore, in order to extend the service life of the air compressor housing, this Example further includes the following technical solution.

[0088] As shown in FIGS. 3 and 8, the box body 26 is provided with openings 27; further comprises a steel sleeve 28 and a bearing 29. Both the steel sleeve 28 and the bearing 29 are arranged inside the box body 26, and, the steel sleeve 28 is located between the bearing 29 and the box body 26 along the radial direction of the bearing 29; the crankshaft assembly 23 is rotatably connected to the steel sleeve 28 through the bearing 29; further comprises a connecting member 30 and a foot pad 31, one end of the connecting member 30 is connected to the steel sleeve 28, and the other end passes through the opening 27 of the box body 26 and is connected to the foot pad 31.

[0089] The number of the openings 27, the number of the connecting members 30 and the number of the foot pads 31 are all the same. That is, the number of the openings 27 matches the number of the connecting members 30 and the foot pads 31, respectively. For example, in this Example, the box body 26 is provided with two openings 27 on both side, and the number of the connecting members 30 and the foot pads 31 is also two, respectively. One end of one connecting member 30 passes through one opening 27 and is connected to one foot pad 31, and the other connecting member 30 passes through the other opening 27 and is connected to the other foot pad 31.

[0090] The connecting member 30 may be a plate structure made of metal.

[0091] In this Example, the crankshaft assembly 23 is connected to the steel sleeve 28 through the bearing 29, and the steel sleeve 28 is connected to the foot pad 31 through the connecting member 30, thereby transferring the downward force generated by the combined weight of the crankshaft assembly 23, the low-pressure piston assembly 7 and the high-pressure piston assembly 9, as well as the torque from the motion of the low-pressure piston assembly 7 and the high-pressure piston assembly 9, to the foot pad 31 through the bearing 29, the steel sleeve 28 and the connecting member 30, so as to divert most of the force and torque originally acting on the air compressor box body 26, reduce the force and torque acting on the air compressor box body 26, and effectively extends the service life of the box body 26 of the air compressor.

[0092] Further, in the prior art, the crankshaft assembly is directly connected to the box body through bearings. During the operation of the air compressor, due to mechanical friction and the work done by compressing gas, a large amount of heat may be generated inside the box body, raising the temperature of the box body. However, the box body is made of aluminum material, the crankshaft assembly, bearings, and the like are made of steel. The thermal expansion coefficient of aluminum is greater than that of steel. This leads to, the expansion deformation degree of the box body is different from that of the crankshaft assembly and the bearing along the direction from top to bottom in FIG. 3, i.e., one radial direction of the bearing when heated. The expansion deformation of the box body is greater, causing the gap between the box body and the bearing to increase, resulting in the bearing moving downward and the crankshaft assembly connected to the bearing moving downward.

[0093] In this Example, a steel sleeve 28 made of steel is arranged between the bearing 29 and the box body 26, that is, the outer ring of the bearing 29 is fixed to the steel sleeve 28, and the material of the steel sleeve 28 is consistent with that of the crankshaft assembly 23 and the bearing 29. A large amount of heat may be generated inside the box body 26, and during the process of increasing the temperature of the box body, the thermal expansion deformation degree and amount of the bearing 29 and the steel sleeve 28 are consistent along the direction from top to bottom in FIG. 3, i.e., one radial direction of the bearing 29. No gap is generated between the outer ring of the bearing 29 and the steel sleeve 28, thereby avoiding the situation of the bearing 29 moving downward and the crankshaft assembly 23 connected to the bearing 29 moving downward.

[0094] Further, as shown in FIGS. 3 and 9, in this Example, the outer ring surface of the bearing 29 is provided with a first engagement slot 34, the steel sleeve 28 is provided with a first engagement hole 43; further comprises an engagement member 35. One end of the engagement member 35 is inserted into the first engagement hole 43, and the other end is engaged into the first engagement slot 34.

[0095] The engagement member 35 may be selected from structures such as a screw, a bolt, a pin, or a threaded locking pin. Preferably, in order to increase the connection strength between the engagement member 35 and the first engagement hole 43, the engagement member 35 is a threaded locking pin. The outer surface has first external threads, and the hole wall of the first engagement hole 43 is machined with first internal threads. The engagement member 35 (i.e., the threaded locking pin) is connected to the first engagement hole 43 by threaded engagement.

[0096] During startup and shutdown of the air compressor, the vibration impact from the motor is significant. This vibration easily causes a circumferential misalignment between the outer ring of the bearing 29 and the inner ring of the steel sleeve 28. Such misalignment is also called the slipping creep phenomenon of the bearing 29 relative to the steel sleeve 28. Over time, it may easily lead to the outer ring of the bearing 29 being worn by the inner ring of the steel sleeve 28.

[0097] In this Example, through the engagement of the engagement member 35 and the first engagement hole 43, the outer ring of the bearing 29 and the inner ring of the steel sleeve 28 are fixed together. Since the outer ring of the bearing 29 and the inner ring of the steel sleeve 28 are relatively fixed, it avoids the phenomenon of circumferential misalignment between the outer ring of the bearing 29 and the inner ring of the steel sleeve 28 caused by the startup and shutdown of the air compressor. This further avoids the aforementioned slipping creep phenomenon of the bearing 29 relative to the steel sleeve 28, and also avoids the situation of the outer ring of the bearing 29 being worn by the inner ring of the steel sleeve 28.

[0098] Further, as shown in FIG. 3, the inner wall of the box body 26 of the air compressor in this Example is further machined with a dust collection groove 44. The opening of the dust collection groove 44 faces the crankshaft assembly 23. The dust collection groove 44 is used to collect debris falling from the power parts inside the box body 26 of the air compressor, such as debris falling from the surface of the crankshaft 41 due to friction between the crankshaft 41 and the bearing connected to it, debris falling from the outer surface of the high-pressure piston assembly 9 due to friction with the inner wall of the high-pressure chamber 8, and debris falling from the outer surface of the low-pressure piston assembly 7 due to friction with the inner wall of the primary compression chamber 4, etc.Example 2

[0099] This Example provides a vehicle, which comprises the oil-free air compressor of Example 1.

[0100] The above Examples only express several implementation modes of the present invention, and their description is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that for those of ordinary skill in the art, several modifications and improvements may be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be based on the appended claims.

Claims

1. An oil-free air compressor, wherein, comprising a cylinder body, the cylinder body is internally provided with a primary compression chamber, a primary exhaust chamber and a high-pressure chamber;wherein the primary compression chamber and the primary exhaust chamber are coaxially arranged and are respectively parallel to the axis of the high-pressure chamber; the sum of the axial length of the primary compression chamber and the axial length of the primary exhaust chamber is less than the axial length of the high-pressure chamber;further comprising a first valve plate assembly, the first valve plate assembly is arranged between the primary compression chamber and the primary exhaust chamber; the first valve plate assembly is provided with a first check valve body, the first check valve is used to allow unidirectional flow from the primary compression chamber to the primary exhaust chamber;further comprising a box body, the box body is located below the cylinder body and is connected to the cylinder body;further comprising a crankshaft assembly, a low-pressure connecting rod and a low-pressure piston assembly; the crankshaft assembly is arranged inside the box body, and the primary compression chamber is located between the primary exhaust chamber and the crankshaft assembly; the low-pressure piston assembly is movably arranged inside the primary compression chamber and is connected to the crankshaft assembly through the low-pressure connecting rod;further comprising a high-pressure connecting rod and a high-pressure piston assembly; the high-pressure piston assembly is movably arranged inside the high-pressure chamber and is connected to the crankshaft assembly through the high-pressure connecting rod;the direction from the primary compression chamber pointing to the primary exhaust chamber is defined as upward, and the opposite direction is defined as downward, along the axial direction of the primary compression chamber and the primary exhaust chamber;the top dead center of the high-pressure piston assembly is located above the first valve plate assembly, and the top dead center of the motion of the low-pressure piston assembly is located below the first valve plate assembly.

2. The oil-free air compressor according to claim 1, wherein, further comprising an intercooler valve plate and a cylinder head; the combination of the intercooler valve plate and the cylinder head covers the cylinder body, and the intercooler valve plate is located between the cylinder head and the cylinder body;the cylinder head and the intercooler valve plate jointly define a secondary exhaust chamber; the intercooler valve plate is provided with a second check valve body, the second check valve body may allow unidirectional flow from the high-pressure chamber to the secondary exhaust chamber;the secondary exhaust chamber is provided with a noise reduction rib, the noise reduction rib extends along the axial direction of the primary compression chamber;one end of the noise reduction rib is connected to the inner wall of the secondary exhaust chamber, and the other end is not in contact with any inner wall of the secondary exhaust chamber.

3. The oil-free air compressor according to claim 2, wherein, the number of the noise reduction ribs is multiple, and the multiple noise reduction ribs are arranged parallel to each other at intervals.

4. The oil-free air compressor according to claim 2, wherein, further comprising an intercooler, the intercooler is used to drive the external air of the oil-free air compressor to flow and form cooling air;further comprising a first air blowing channel, the first air blowing channel is used to deliver a portion of the cooling air;a first air duct is provided within the side wall of the cylinder body; the intercooler valve plate is provided with a second through hole; a second air duct is provided within the cylinder head, and the second air duct (1forms a first air outlet on the surface of the cylinder head;the first air duct, the second through hole, the second air duct and the first air outlet are respectively components of the first air blowing channel.

5. The oil-free air compressor according to claim 4, wherein, the outer surface of the cylinder head is provided with a heat dissipation rib, and the first air outlet faces the heat dissipation rib.

6. The oil-free air compressor according to claim 4, wherein, further providing a second air blowing channel; one end of the second air blowing channel is connected to the first air duct, and the other end intersects with the side wall of the cylinder head to form a second air outlet.

7. The oil-free air compressor according to claim 1, wherein, the box body is provided with an opening;further comprising a steel sleeve and a bearing; both the steel sleeve and the bearing are arranged inside the box body, and, the steel sleeve is located between the bearing and the box body along the radial direction of the bearing; the crankshaft assembly is rotatably connected to the steel sleeve through the bearing;further comprising a connecting member and a foot pad; one end of the connecting member is connected to the steel sleeve, and the other end passes through the opening of the box body and is connected to the foot pad.

8. The oil-free air compressor according to claim 7, wherein, the outer ring surface of the bearing is provided with a first engagement slot, the steel sleeve is provided with a first engagement hole; further comprising an engagement member, one end of the engagement member is inserted into the first engagement hole, and the other end is engaged into the first engagement slot.

9. The oil-free air compressor according to claim 7, wherein, the number of the openings, the number of the connecting members and the number of the foot pads are all the same.

10. A vehicle, wherein, comprising the oil-free air compressor according to claim 1.

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