Double-piston assembly, two-stage compressor and vehicle

Abstract

The embodiment of the invention discloses a double-piston assembly, a two-stage compressor and a vehicle. The double-piston assembly comprises a piston frame, a first piston, a second piston, a bush and a sliding block, an installation groove is formed in the piston frame, the first piston and the second piston are connected through the piston frame, the bush is installed in the installation groove, a sliding groove is formed in the bush, and the sliding groove is provided with a first guide face and a second guide face which are parallel to each other and face each other in the first direction. The sliding block is arranged in the sliding groove in a matched mode, can move in the sliding groove in the second direction orthogonal to the first direction and is guided by the first guiding face and the second guiding face. The double-piston assembly is more compact in structure, low in manufacturing and maintenance cost and long in service life.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular to a dual-piston assembly, a two-stage compressor and a vehicle. Background Art

[0002] A compressor is a widely used air compression device, which can also be generally referred to as an air pump. It can be used to supply compressed air to pneumatic devices, such as air springs, of vehicles such as off-road vehicles, sport utility vehicles (SUVs), passenger vehicles and commercial vehicles. In order to improve the compression efficiency, the related art proposes a two-stage compressor, which has two pistons rigidly connected to each other by a piston rack, and the piston rack is connected to the drive shaft by a crank-connecting rod mechanism, and the two pistons are radially opposite to the rotation axis of the drive shaft. Due to the large size of the connecting rod of the crank-connecting rod mechanism and the large space required for the movement of the crank-connecting rod mechanism, the compressor is large in size and difficult to miniaturize. The related art also proposes a two-stage compressor, in which the piston rack is connected to the drive shaft by a slide guide device, but this two-stage compressor has the problems of high manufacturing cost, short service life, and high noise after a period of use. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention provides a dual-piston assembly with low manufacturing cost and long service life.

[0005] An embodiment of the present invention further provides a two-stage compressor having the dual-piston assembly of the above embodiment.

[0006] An embodiment of the present invention further provides a vehicle having the two-stage compressor of the above embodiment.

[0007] The dual-piston assembly of an embodiment of the present invention includes a piston frame, a first piston, a second piston, a bushing and a slider, the piston frame having a mounting groove, the first piston and the second piston being connected to each other through the piston frame, the bushing being mounted in the mounting groove, the bushing having a slide groove, the slide groove having a first guide surface and a second guide surface which are parallel to each other and face each other in a first direction (A), the slider being fitted in the slide groove, the slider being movable in the slide groove along a second direction (B) orthogonal to the first direction and being guided by the first guide surface and the second guide surface.

[0008] The double piston assembly of the embodiment of the present invention has a more compact structure and can reciprocate in a smaller space. Moreover, by adding a bushing to the piston frame, the slider slides in the slide groove of the bushing, and the entire piston frame does not need to be made of wear-resistant materials, nor does it need to be subjected to wear-resistant treatment. After the bushing is worn, only the bushing needs to be repaired, such as spraying a wear-resistant coating on the first guide surface and the second guide surface, or only the bushing needs to be replaced without replacing the entire piston frame, thereby reducing manufacturing and maintenance costs and increasing the service life of the piston frame.

[0009] The two-stage compressor of an embodiment of the present invention includes a cylinder, a double-piston assembly and a driving device, the cylinder having a first compression chamber and a second compression chamber, the double-piston assembly is the double-piston assembly described in the above embodiment, the first piston is movably disposed in the cylinder for compressing the gas in the first compression chamber, the second piston is movably disposed in the cylinder for compressing the gas in the second compression chamber, the first compression chamber and the second compression chamber are connected by a connecting air passage running through the piston frame, the first piston and the second piston, and the driving device is connected to the slider for driving the slider to slide in the slide groove.

[0010] The vehicle of the embodiment of the present invention comprises a pneumatic device and the two-stage compressor described in the above embodiment, wherein the two-stage compressor is connected to the pneumatic device and is used to supply compressed air to the pneumatic device. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of an explosion of a dual piston assembly according to a first embodiment of the present invention.

[0012] Figure 2 1 is a side view of a dual piston assembly according to a first embodiment of the present invention.

[0013] Figure 3 Schematic cross-sectional view of a dual-piston assembly according to a first embodiment of the present invention.

[0014] Figure 4 Schematic diagram of an explosion of a two-stage compressor according to an embodiment of the present invention.

[0015] Figure 5 It is a cross-sectional schematic diagram of a two-stage compressor according to an embodiment of the present invention.

[0016] Figure 6 It is a schematic cross-sectional view of a cylinder liner of a two-stage compressor according to an embodiment of the present invention.

[0017] Figure 7 It is a partial exploded schematic diagram of a dual-piston assembly according to a second embodiment of the present invention.

[0018] Figure 8Schematic diagram of an explosion of a dual piston assembly according to a second embodiment of the present invention.

[0019] Fig. 9 4 is a cross-sectional schematic diagram of a dual-piston assembly according to a second embodiment of the present invention.

[0020] Fig.10 Schematic diagram of an explosion of a dual-piston assembly according to a third embodiment of the present invention.

[0021] Fig.11 4 is a cross-sectional schematic diagram of a dual-piston assembly according to a third embodiment of the present invention.

[0022] Fig.12 Schematic diagram of an explosion of a dual-piston assembly according to a fourth embodiment of the present invention.

[0023] Fig.13 4 is a cross-sectional schematic diagram of a dual-piston assembly according to a fourth embodiment of the present invention.

[0024] Fig.14 It is a schematic structural diagram of the valve plate of the two-stage compressor according to an embodiment of the present invention.

[0025] Fig.15 It is a schematic cross-sectional view of a valve plate of a two-stage compressor according to an embodiment of the present invention.

[0026] Fig.16 It is a cross-sectional schematic diagram of another valve plate of the two-stage compressor according to an embodiment of the present invention.

[0027] Fig.17 It is a partial schematic diagram showing that the valve plate of the two-stage compressor according to an embodiment of the present invention is in a closed state.

[0028] Fig.18 It is a partial schematic diagram showing that the valve plate of the two-stage compressor according to an embodiment of the present invention is in an open state.

[0029] Fig.19 Schematic diagram of an explosion of a two-stage compressor according to another embodiment of the present invention.

[0030] Fig. 20 It is a cross-sectional schematic diagram of a two-stage compressor according to another embodiment of the present invention.

[0031] Fig.21 It is a cross-sectional schematic diagram of the assembled planetary reduction assembly and motor of the two-stage compressor according to another embodiment of the present invention.

[0032] Fig. 22 It is an exploded schematic diagram of a planetary reduction assembly and a motor of a two-stage compressor according to another embodiment of the present invention.

[0033] Fig.23 It is a three-dimensional schematic diagram of a crankshaft of a two-stage compressor according to another embodiment of the present invention.

[0034] Fig.24 2 is a perspective schematic diagram of a vehicle according to an embodiment of the present invention.

[0035] Reference numerals:

[0036] 100. Vehicle; 10012. Secondary compressor; 1002. Pneumatic device;

[0037] 1. Cylinder; 1011. First cylinder cavity; 1012. Second cylinder cavity; 1021. First compression chamber; 1022. Second compression chamber; 11. Cylinder body; 111. Intake passage; 112. Front bearing; 113. Intake port; 114. Exhaust port; 12. Cylinder liner; 121. Wear-resistant layer; 122. Oblique port; 13. Cylinder head; 15. Exhaust valve;

[0038] 2. Double piston assembly; 201. Connecting air passage; 202. Valve plate mounting groove;

[0039] 21. Piston rack;

[0040] 211, mounting slot;

[0041] 221, first piston; 2211, first piston head; 22111, air intake hole; 2212, first piston ring; 2213, pressure ring; 2214, first guide ring;

[0042] 222, second piston; 2221, second piston head; 2222, second piston ring; 2223, second guide ring;

[0043] 223, fixed part;

[0044] 224, flange;

[0045] 23, bushing; 231, slide groove; 2311, first guide surface; 2312, second guide surface; 232, first bushing body; 2321, first groove; 2322, first elastic member; 233, second bushing body; 2331, second groove; 2332, second elastic member;

[0046] 24, slider; 241, first working surface; 2411, first receiving groove; 2412, first rolling element; 242, second working surface; 2421, second receiving groove; 2422, second rolling element; 243, slider hole; 244, slot;

[0047] 25. Bearings;

[0048] 26, bearing seat; 261, lug; 262, seat hole;

[0049] 3. Planetary reduction assembly; 301. Matching hole; 31. Internal gear ring; 311. Cylinder; 312. Annular boss; 32. Planet carrier; 321. Assembly groove; 322. Rear bearing; 33. Sun gear; 34. Planet gear; 35. Planet gear shaft;

[0050] 4. Motor; 401. Matching part; 41. Motor shaft; 42. Motor housing; 43. Motor rear end cover; 44. Rotor; 45. Stator; 46. Rotor front bearing; 47. Rotor rear bearing; 48. Sealing ring;

[0051] 5. crankshaft; 51. main shaft; 511. assembly hole; 52. eccentric shaft; 53. balance block;

[0052] 7. Dryer; 71. Air outlet;

[0053] 8, valve disc; 81, disc body; 82, slot; 821, outer slot section; 822, inner slot section; 823, connecting slot section; 83, sealing portion; 84, mounting portion; 85, swing arm; 86, first connecting portion; 87, second connecting portion; 801, first valve disc; 802, second valve disc;

[0054] 9. Driving device. DETAILED DESCRIPTION

[0055] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0056] The dual piston assembly according to the embodiment of the present invention will be described below with reference to the accompanying drawings.

[0057] like Figure 1-Figure 24 As shown, the dual-piston assembly 2 includes a piston frame 21 , a first piston 221 , a second piston 222 , a bushing 23 and a slider 24 .

[0058] The piston frame 21 can also be generally referred to as a piston rod. The first piston 221 and the second piston 222 are connected to each other through the piston frame 21. In other words, the piston frame 21 has a first end and a second end along its length direction. The first piston 221 is arranged at the first end of the piston frame 21, and the second piston 222 is arranged at the second end of the piston frame 21.

[0059] The piston frame 21 has a mounting groove 211 therein, for example, the middle cross section of the piston frame 21 is enlarged, and the mounting groove 211 is formed in the middle of the piston frame 21. The bushing 23 is installed in the mounting groove 211. Preferably, the bushing 23 is detachably installed in the mounting groove 211, for example, the bushing 23 can be pressed into the mounting groove 211 by a cold pressing or hot pressing process. The bushing 23 has a slide groove 231 therein, and the slide groove 231 has a first guide surface 2311 and a second guide surface 2312, the first guide surface 2311 and the second guide surface 2312 face each other in the first direction A, and the first guide surface 2311 and the second guide surface 2312 are parallel to each other.

[0060] The slider 24 is fitted in the slide groove 231 and is movable in the slide groove 231 along a second direction B, wherein the second direction B is orthogonal to the first direction A. The slider 24 is guided by the first guide surface 2311 and the second guide surface 2312 to slide in the slide groove 231 .

[0061] In some specific examples, the first direction A may be a length direction of the piston frame 21 , and the second direction B may be a width direction of the piston frame 21 .

[0062] In some specific examples, the sizes of the first piston 221 and the second piston 222 may be different. For example, the diameter of the first piston 221 is larger than the diameter of the second piston 222. The first piston 221 may be called a low-pressure side piston, and the second piston 222 may be called a high-pressure side piston. The air compressed by the first piston 221 may be compressed by the second piston 222 for the second time.

[0063] In the dual-piston assembly 2 of the embodiment of the present invention, the slider 24 is driven by the driving device 9 to move back and forth in the slide groove 231 to drive the first piston 221 and the second piston 222 to compress the air.

[0064] Compared with the crank-connecting rod mechanism used in the related art, the dual piston assembly of the embodiment of the present invention adopts a slider and a slide groove structure, which is more compact, so that it can reciprocate in a smaller space, which is conducive to the miniaturization of the dual piston assembly. In addition, the dual piston assembly of the embodiment of the present invention, by adding a bushing in the piston frame, the slider slides in the slide groove of the bushing. During manufacturing, the entire piston frame does not need to be made of wear-resistant materials, and the piston frame does not need to be wear-resistant, which reduces costs. Moreover, after the bushing is worn, only the worn surface of the bushing can be repaired, such as spraying a wear-resistant coating on the first guide surface and the second guide surface, or only replacing the bushing without replacing the entire piston frame, which reduces manufacturing and maintenance costs and increases the service life of the piston frame.

[0065] In some examples, such as Figure 1-Figure 20 As shown, the first piston 221 and / or the second piston 222 is provided with a valve plate 8. Preferably, as Figure 1As shown, the first piston 221 is provided with a first valve plate 801 , and the second piston 222 is provided with a second valve plate 802 . The first valve plate 801 and the second valve plate 802 can be referred to as intake valve plates. Here, the first valve plate 801 and the second valve plate 802 can be collectively referred to as valve plates 8 .

[0066] like Figure 14-Figure 18 As shown, the valve plate 8 includes a plate body 81, and the plate body 81 is provided with a slot 82, and the slot 82 penetrates the plate body 81 along the thickness direction of the plate body 81. The slot 82 divides the plate body 81 into a sealing portion 83, a mounting portion 84 and a plurality of swing arms 85. The sealing portion 83 and the mounting portion 84 are concentric with each other, that is, the center of the sealing portion 83 coincides with the center of the mounting portion 84, and the mounting portion 84 is arranged around the sealing portion 83.

[0067] The swing arm 85 is an elastic arm, and the width of the swing arm 85 is substantially constant in the length direction thereof. The first end of the swing arm 85 is connected to the sealing portion 83 , and the second end of the swing arm 85 is connected to the mounting portion 84 .

[0068] When the number of the swing arms 85 is an even number, the plurality of swing arms 85 are arranged in pairs, that is, the plurality of swing arms 85 are divided into at least one pair, and the two swing arms 85 in the same pair of swing arms 85 are centrally symmetrical with respect to the center of the sealing portion 83, that is, one swing arm 85 rotates 180 degrees and overlaps with the other swing arm 85. When the number of the swing arms 85 is an odd number, the plurality of swing arms 85 are uniformly arranged around the center of the sealing portion 83 along the circumference of the sealing portion 83, for example, the number of the swing arms 85 is N, N is an odd number, and of two adjacent swing arms 85, one swing arm 85 rotates 360 / N degrees around the center of the sealing portion 83 and overlaps with the other swing arm 85.

[0069] In the embodiment of the present invention, the swing arms 85 are centrally symmetrical or evenly arranged along the circumference of the sealing portion 83, which improves the force uniformity of the sealing portion 83 and improves the uniformity of the valve plate 8 in opening and closing the valve port.

[0070] Optionally, the thickness T of the sheet body 81 may be greater than or equal to 0.1 mm and less than or equal to 0.5 mm, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0071] The valve plate 8 may be a metal plate, such as a stainless steel plate or an alloy plate. Alternatively, the valve plate 8 may also be made of a non-metal plate, such as a resin plate whose flexibility and strength meet the design requirements.

[0072] The width of the slot 82 should ensure that the swing arm 85, the sealing portion 83 and the mounting portion 84 do not interfere with each other during the use of the valve plate 8. Preferably, the width H of the swing arm 85 can be greater than or equal to 1.3 mm and less than or equal to 5 mm, and the width of the slot 82 can be greater than or equal to 1 mm and less than or equal to 4 mm. If the swing arm 85 is too narrow, fatigue deformation will occur after the valve plate 8 is used for a period of time. If the swing arm 85 is too wide, the sensitivity of the switch valve port of the sealing portion 83 will be affected. The slot 82 can be formed by stamping a metal sheet. In other words, the valve plate 8 is formed integrally by stamping a metal sheet.

[0073] Compared with the valve disc in the related art, in the embodiment of the present invention, the opening height of the valve disc is uniform, the flow area of ​​the valve port is large at the same opening height, the air flow is smooth, the air resistance is small, and the response speed of the valve disc is high. In addition, the swing arm is symmetrically arranged at the center or evenly arranged along the circumference, so that the sealing part is evenly stressed, which not only improves the sensitivity of the valve disc opening and closing, but also reduces the fatigue of the valve disc after a period of use, thereby extending the service life of the valve disc.

[0074] In addition, compared with the width variation of the swing arm of the valve plate in the related art, in the embodiment of the present invention, the width of the swing arm is generally consistent in its length direction, which further improves the force uniformity of the sealing part and the uniformity of the opening and closing of the valve port, thereby further improving the response speed and sensitivity of the valve plate.

[0075] In some specific examples, such as Fig.14 and Fig.15 As shown, the sheet body 81 can be a stainless steel sheet with a thickness of 0.1 mm. The sealing portion 83 is circular, and the mounting portion 84 is annular and surrounds the sealing portion 83. The swing arm 85 is in an arc shape, and the width H of the swing arm 85 can be 5 mm. There are two swing arms 85 and they are centrally symmetrical with respect to the center of the sealing portion 83. The swing arm 85 is connected to the sealing portion 83 through the first connecting portion 86 and is connected to the mounting portion 84 through the second connecting portion 87, so that the width of the swing arm 85 can be more uniform, further improving the uniformity of the valve plate 8 opening and closing the valve port.

[0076] There are two slots 82, each of which includes an outer slot segment 821, an inner slot segment 822, and a connecting slot segment 823 connected between the outer slot segment 821 and the inner slot segment 822. Fig.15 As shown, one swing arm 85 is located between the outer slot segment 821 of one slot 82 and the inner slot segment 822 of another slot 82 , and the other swing arm 85 is located between the inner slot segment 822 of the one slot 82 and the outer slot segment 821 of the other slot 82 .

[0077] The outer slot segment 821 and the inner slot segment 822 are both arc-shaped, and the connecting slot segment 823 is composed of a plurality of arc segments protruding in different directions and smoothly connected to each other. The center angle θ of the inner slot segment 822 and the outer slot segment 821 is equal, and preferably, the center angle θ is greater than or equal to 120 degrees and less than or equal to 150 degrees. Fig.14 and Fig.15 In the embodiment shown, the central angle θ is 120 degrees.

[0078] In other specific examples, such as Fig.16 As shown, the sheet 81 can be a stainless steel sheet with a thickness of 0.3 mm. The sealing portion 83 is circular, and the mounting portion 84 is annular and surrounds the sealing portion 83. The swing arm 85 is in an arc shape, and the width H of the swing arm 85 can be 4 mm. There are three swing arms 85 and they are evenly arranged around the center of the sealing portion 83 along the circumference of the sealing portion 83. The swing arm 85 is connected to the sealing portion 83 through the first connecting portion 86 and connected to the mounting portion 84 through the second connecting portion 87.

[0079] There are three slots 82, each of which includes an outer slot segment 821, an inner slot segment 822, and a connecting slot segment 823 connecting the outer slot segment 821 and the inner slot segment 822. Fig.16 As shown, each swing arm 85 is located between an outer slot segment 821 of a slot 82 and an inner slot segment 822 of another adjacent slot 82. The outer slot segment 821 and the inner slot segment 822 are both arc-shaped, and preferably, the central angle θ is greater than or equal to 60 degrees and less than or equal to 90 degrees.

[0080] The installation and operation of the valve plate will be described below by taking the valve plate (second valve plate) provided on the second piston as an example.

[0081] like Fig.17 and Fig.18 As shown, a valve plate mounting groove 202 is provided on the second piston 222, and the second valve plate 802 is installed in the valve plate mounting groove 202. The mounting portion 84 is fixed by the fixing portion 223 on the second piston 222, and the sealing portion 83 is opposite to the port (also called the valve port) of the connecting air channel 201 that passes through the second piston 222.

[0082] Preferably, a flange 224 surrounding the valve port is provided on the surface of the second piston 222, and the upper surface of the flange 224 can be referred to as a sealing surface. Fig.17 As shown, when the air pressure in the communicating air passage 201 is less than the sum of the elastic force of the swing arm 85 and the air pressure in the compression chamber (the second compression chamber 1022), the valve plate 8 presses on the upper surface of the flange 224 to close the valve port. Fig.18As shown, when the air pressure in the connecting air channel 201 is greater than the sum of the elastic force of the swing arm 85 and the air pressure in the second compression chamber 1022, the gas in the connecting air channel 201 pushes the sealing portion 83 to move upward and away from the sealing surface, thereby opening the valve port, and the air flow F in the connecting air channel 201 enters the second compression chamber 1022 through the slot 82 of the valve plate 8.

[0083] A dual-piston assembly according to a first embodiment of the present invention will be described below with reference to the accompanying drawings.

[0084] like Figure 1-Figure 3 As shown, the dual-piston assembly 2 includes a piston frame 21 , a first piston 221 , a second piston 222 , a bushing 23 , a slider 24 and a bearing 25 .

[0085] The piston frame 21 has a first end and a second end in the length direction thereof. The first piston 221 is disposed at the first end of the piston frame 21 , and the second piston 222 is disposed at the second end of the piston frame 21 .

[0086] The first piston 221 includes a first piston head 2211, a first piston ring 2212, a pressure ring 2213 and a first guide ring 2214. The first piston head 2211 has a first piston ring groove, and the first piston ring 2212 is assembled in the first piston ring groove. The pressure ring 2213 is mounted on the first piston head 2211, and the pressure ring 2213 has a first guide ring groove, and the first guide ring 2214 is assembled in the first guide ring groove.

[0087] The first piston head 2211 is provided with an air intake hole 22111, and external air enters the first compression chamber 1021 through the air intake hole 22111. A first valve plate 801 is provided on the surface of the first piston head 2211. The first valve plate 801 may be the valve plate 8 of the above-mentioned embodiment, and is used to open and close the port (valve port) of the air intake hole 22111. Figure 1 As shown, in this embodiment, there are two first valve plates 801, and accordingly, there are two air intake holes 22111 to meet the air intake demand.

[0088] The second piston 222 includes a second piston head 2221, a second piston ring 2222 and a second guide ring 2223. The second piston head 2221 has a second piston ring groove and a second guide ring groove, the second piston ring 2222 is assembled in the second piston ring groove, and the second guide ring 2223 is assembled in the second guide ring groove.

[0089] like Figure 3 As shown, the dual-piston assembly 2 includes a connecting air channel 201 that passes through the first piston 221, the piston rack 21 and the second piston 222. A second valve plate 802 is provided on the surface of the second piston head 2221 for opening and closing the port (valve port) of the connecting air channel 201. The second valve plate 802 can be the valve plate 8 of the above-mentioned embodiment.

[0090] The middle part of the piston frame 21 has a substantially rectangular mounting groove 211. The bushing 23 is in a rectangular ring shape, and the bushing 23 is detachably mounted in the mounting groove 211, for example, the bushing 23 is pressed into the mounting groove 211 by a hot pressing or cold pressing process. The inner cavity of the bushing 23 constitutes a slide groove 231, which is substantially rectangular and has a first guide surface 2311 and a second guide surface 2312 facing each other in the first direction A, and a wear-resistant coating is provided on the first guide surface 2311 and the second guide surface 2312 to improve the wear resistance of the bushing 23. The wear-resistant coating can be formed on the first guide surface 2311 and the second guide surface 2312 by spraying or electroplating.

[0091] The slider 24 is slidably engaged in the slide groove 231 along a second direction B orthogonal to the first direction A. Specifically, the slider 24 has a first working surface 241 and a second working surface 242 which are separated from each other along the first direction A. The first working surface 241 is in sliding contact with the first guide surface 2311, and the second working surface 242 is in sliding contact with the second guide surface 2312.

[0092] The wear coefficient of the slider 24 is greater than the wear coefficient of the bushing 23. In other words, the bushing 23 is more wear-resistant than the slider 24, thereby extending the service life of the bushing 23. The slider 24 is easier to replace than the bushing 23, which can improve maintenance efficiency.

[0093] For example, the bushing 23 can be made of metal, the slider 24 can be made of a low friction coefficient composite material, such as a polytetrafluoroethylene-based composite material or a polyetheretherketone-based composite material, or the surface of the slider 24 is provided with a low friction coefficient composite material layer. For example, the composite material or the composite material layer can be formed by adding graphite, copper powder, carbon fiber or glass fiber to a composite polytetrafluoroethylene material.

[0094] The slider 24 has a slider hole 243, and the bearing 25 is assembled in the slider hole 243. The bearing 25 can be connected to the driving shaft that drives the dual piston assembly 2, so that the slider 24 is driven to slide back and forth in the slide groove 231, thereby driving the first piston 221 and the second piston 222 to move.

[0095] A dual-piston assembly according to a second embodiment of the present invention will be described below with reference to the accompanying drawings.

[0096] like Figure 7-Figure 9 As shown, the dual-piston assembly 2 includes a piston frame 21 , a first piston 221 , a second piston 222 , a bushing 23 , a slider 24 , a bearing seat 26 and a bearing 25 .

[0097] The slider 24 has a slider hole 243 in it, and the bearing seat 26 is installed in the slider hole 243. An anti-rotation structure for preventing the bearing seat 26 from rotating relative to the slider 24 is provided between the slider 24 and the bearing seat 26. In one example, the anti-rotation structure includes a slot 244 and a lug 261. The slot 244 can be provided on the end surface of the slider 24, and the lug 261 is provided on the bearing seat, and the lug 261 is fitted in the slot 244, so that the bearing seat 26 can be prevented from rotating relative to the slider 24, thereby improving the firmness of the bearing seat 26. The bearing seat 26 has a seat hole 262 in it, and the bearing 25 is installed in the seat hole 262 of the bearing seat 26. In an optional example, the slider hole 243 is non-circular, and the cross-sectional profile of the bearing seat 26 is non-circular to match the slider hole 243, so that when the bearing seat 26 is installed in the slider hole 243, the bearing seat 26 can be prevented from rotating relative to the slider 24. In this example, the non-circular slider hole and the non-circular cross-sectional profile of the bearing seat constitute an anti-rotation structure.

[0098] The bearing seat can be a metal bearing seat, and the slider can be made of a resin composite material, such as a polytetrafluoroethylene-based composite material or a polyetheretherketone-based composite material. Since the bearing seat is a metal bearing seat, compared with the slider, the bearing seat is not easily thermally expanded during the operation of the double piston assembly, so that the bearing is not easy to loosen in the bearing seat, thereby improving the firmness of the bearing and reducing noise.

[0099] Other aspects of the dual-piston assembly of the second embodiment of the present invention may be similar to those of the dual-piston assembly of the above embodiment, and will not be described in detail herein.

[0100] A dual-piston assembly according to a third embodiment of the present invention will be described below with reference to the accompanying drawings.

[0101] like Fig.10 and Fig.11 As shown, the dual-piston assembly 2 includes a piston frame 21 , a first piston 221 , a second piston 222 , a bushing 23 , a slider 24 , a bearing seat 26 and a bearing 25 .

[0102] The bushing 23 includes a first bushing body 232 and a second bushing body 233, the first bushing body 232 and the second bushing body 233 are U-shaped, and the first bushing body 232 and the second bushing body 233 are butted along a first direction A to define a slide groove 231 located in the bushing 23. Preferably, the first bushing body 232 and the second bushing body 233 are symmetrical to each other. By dividing the bushing 23 into the first bushing body 232 and the second bushing body 233, the processing of the bushing 23 can be simplified, and the first bushing body 232 and the second bushing body 233 can be replaced separately, thereby reducing the manufacturing and maintenance costs.

[0103] The first bushing body 232 has a first outer surface, and the first outer surface is provided with a first groove 2321. A first elastic member 2322 is provided in the first groove 2321, and the first elastic member 2322 is stopped between the mounting groove 211 and the first bushing body 232. The second bushing body 233 has a second outer surface, and a second groove 2331 is provided in the second outer surface. A second elastic member 2332 is provided in the second groove 2331, and the second elastic member 2332 is stopped between the mounting groove 211 and the second bushing body 233. The first bushing body 232 and the second bushing body 233 are pressed toward each other by the first elastic member 2322 and the second elastic member 2332. For example, the first elastic member 2322 and the second elastic member 2332 are corrugated plates or curved plates.

[0104] The first elastic member and the second elastic member can ensure that the first bushing body and the second bushing body are reliably docked, the first guide surface of the first bushing body is reliably in contact with the first working surface of the slider, and the second guide surface of the second bushing body is reliably in contact with the second working surface of the slider, thereby reducing the impact noise when the slider slides and reverses.

[0105] Other aspects of the dual-piston assembly of the third embodiment of the present invention may be similar to those of the dual-piston assembly of the above-mentioned embodiments, and will not be described in detail herein.

[0106] A dual-piston assembly according to a fourth embodiment of the present invention will be described below with reference to the accompanying drawings.

[0107] like Fig.12 and Fig.13 As shown, the dual-piston assembly 2 includes a piston frame 21 , a first piston 221 , a second piston 222 , a bushing 23 , a slider 24 and a bearing 25 .

[0108] The slide groove 231 has a first guide surface 2311 and a second guide surface 2312. The slider 24 has a first working surface 241 and a second working surface 242. A plurality of first rolling elements 2412 are provided between the first working surface 241 and the first guide surface 2311, and a plurality of second rolling elements 2422 are provided between the second working surface 242 and the second guide surface 2312. The first rolling elements 2412 and the second rolling elements 2422 are, for example, cylinders. The first working surface 241 is provided with a first receiving groove 2411, and the first rolling element 2412 is provided in the first receiving groove 2411. The second working surface 242 is provided with a second receiving groove 2421, and the second rolling element 2422 is provided in the second receiving groove 2421. It can be understood that the first rolling element 2412 is partially exposed from the first receiving groove 2411 to contact the first guide surface 2311 of the bushing 23 , and the second rolling element 2422 is partially exposed from the second receiving groove 2421 to contact the second guide surface 2312 of the bushing 23 .

[0109] By providing the first rolling element 2412 and the second rolling element 2422, when the slider 24 moves in the slide groove 231, the rolling friction between the slider 24 and the bushing 23 reduces the wear of the slider 24 and the bushing 23, and the processing accuracy requirements of the bushing 23 and the slider 24 are reduced, thereby reducing the manufacturing cost. The first guide surface 2311, the second guide surface 2312, the groove surfaces of the first accommodating groove 2411 and the second accommodating groove 2421, and the surfaces of the first rolling element 2412 and the second rolling element 2422 can be hard surfaces that have been polished, with a surface hardness of ≥50HRC and a surface finish of ≤Ra0.8.

[0110] Other aspects of the dual-piston assembly of the fourth embodiment of the present invention may be similar to those of the dual-piston assembly of the above-mentioned embodiments, and will not be described in detail herein.

[0111] The two-stage compressor according to the embodiment of the present invention will be described below with reference to the accompanying drawings.

[0112] like Figure 1-Figure 24 As shown, the two-stage compressor 10012 of the embodiment of the present invention includes a cylinder 1, a dual-piston assembly 2 and a driving device 9.

[0113] The cylinder 1 comprises a cylinder body 11 and a cylinder head 13. The cylinder head 13 is mounted on the cylinder body 11, for example, detachably connected to the cylinder body 11 by bolts. The cylinder body 11 has a first cylinder chamber 1011 and a second cylinder chamber 1012. The cylinder body 11 has an air inlet 113, and the cylinder body 11 has an air inlet passage 111 connected to the air inlet 113.

[0114] The double piston assembly 2 may be the double piston assembly 2 in the above embodiment. The first piston 221 is movably fitted in the first cylinder chamber 1011 and defines a first compression chamber 1021 in the first cylinder chamber 1011, and the second piston 222 is movably fitted in the second cylinder chamber 1012 and defines a second compression chamber 1022 in the second cylinder chamber 1012. The first compression chamber 1021 and the second compression chamber 1022 are connected through a connecting air passage 201 that passes through the piston frame 21, the first piston 221 and the second piston 222.

[0115] The air intake passage 111 in the cylinder body 11 is connected to the first compression chamber 1021 through the air intake through hole 22111 in the first piston head 2211, so that external gas can enter the first compression chamber 1021 from the air intake port 113 through the air intake passage 111 and the air intake through hole 22111. The gas compressed in the first compression chamber 1021 enters the second compression chamber 1022 through the connecting air passage 201 for recompression. The first compression chamber 1021 can be called a primary or low-pressure compression chamber, and the second compression chamber 1022 can be called a secondary or high-pressure compression chamber.

[0116] The driving device 9 includes a motor 4 and a crankshaft 5. The motor 4 has a motor shaft 41, and the crankshaft 5 includes a main shaft portion 51 and an eccentric shaft portion 52. The first end of the eccentric shaft portion 52 is pivotally connected to the slider 24, and the second end of the eccentric shaft portion 52 is connected to the main shaft portion 51. The main shaft portion 51 is coaxially connected to the motor shaft 41, and the central axis of the eccentric shaft portion 52 is eccentric relative to the central axis of the motor shaft 41. The motor 4 drives the slider 24 to slide in the slide groove 231 through the crankshaft 5, thereby driving the first piston 221 to reciprocate in the first compression chamber 1021 through the piston frame 21 and driving the second piston 222 to reciprocate in the second compression chamber 1022.

[0117] Compared with the compressors in the related art that use crank connecting rods, the two-stage compressor of the embodiment of the present invention uses a structure in which a slider and a slide groove cooperate, the size of the piston frame is reduced, the length of the connecting air passage is reduced, the clearance volume of the low-pressure chamber is reduced, the volumetric efficiency of the two-stage compressor is improved, and the structure of the two-stage compressor is more compact, which is conducive to miniaturization. In addition, the bushing in the piston frame is easy to maintain and replace after being worn, and the cost is low.

[0118] A two-stage compressor according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0119] like Figure 4-Figure 6 As shown, the two-stage compressor 10012 includes a cylinder 1, a dual-piston assembly 2, a motor 4, a crankshaft 5 and a dryer 7.

[0120] The cylinder 1 comprises a cylinder body 11, a cylinder head 13 and an exhaust valve 15. The cylinder head 13 is mounted on the lower end of the cylinder body 11, and is detachably connected to the cylinder body 11, for example, by bolts.

[0121] The double piston assembly 2 may be the double piston assembly 2 of the above-mentioned embodiment. The cylinder body 11 has a first cylinder chamber 1011 and a second cylinder chamber 1012. The first piston 221 of the double piston assembly 2 is movably fitted in the first cylinder chamber 1011 and defines a first compression chamber 1021 in the first cylinder chamber 1011, and the second piston 222 is movably fitted in the second cylinder chamber 1012 and defines a second compression chamber 1022 in the second cylinder chamber 1012, and the first compression chamber 1021 and the second compression chamber 1022 are connected through a connecting air passage 201 that passes through the first piston 221, the piston rack 21, and the second piston 222.

[0122] The first piston 221 has an air inlet hole 22111 connected to the first compression chamber 1021, the second compression chamber 1022 has an exhaust port 114, the exhaust valve 15 is arranged at the exhaust port 114, the dryer 7 is connected to the cylinder body 11, so that the compressed air discharged from the second compression chamber 1022 through the exhaust port 114 enters the dryer 7 for drying, and the dried compressed air is discharged from the compressed air outlet (air outlet 71) of the dryer 7.

[0123] The cylinder body 11 has an air inlet 113. The air inlet passage 111 in the cylinder body 11 is connected to the air inlet 113 and the air inlet through hole 22111. A first valve plate 801 is provided at a port where the air inlet through hole 22111 is connected to the first compression chamber 1021. A second valve plate 802 is provided at a port where the air channel 201 is connected to the second compression chamber 1022.

[0124] The upper and lower parts of the cylinder body 11 are provided with cylinder sleeves 12, respectively. In other words, the inner cavity of the lower cylinder sleeve 12 constitutes the first cylinder cavity 1011, and the inner cavity of the upper cylinder sleeve 12 constitutes the second cylinder cavity 1012. The cylinder body 11 can be cast, and the cylinder sleeve 12 can be machined by pipe material, so that the wear-resistant treatment process of the cylinder sleeve 12 is simple, the quality is stable, and the processing accuracy is easy to ensure. There is no need to perform wear-resistant treatment on the cylinder body 11, which reduces the cost.

[0125] The inner wall surface of the cylinder sleeve 12 can be a hard surface that has been polished, with a microhardness of ≥350HV and a surface finish of ≤Ra0.8. The material of the cylinder sleeve 12 can be aluminum alloy, carbon steel, stainless steel, etc., and the surface treatment method can be hard coating or coating (wear-resistant layer 121) such as hard oxidation, hard chrome plating, plasma spraying, etc. Preferably, the inner wall of one end of the cylinder sleeve 12 has a bevel 122 to reduce the probability of damage to the piston ring and the guide ring during the introduction of the first piston 221 and the second piston 222 during assembly.

[0126] The crankshaft 5 includes a main shaft portion 51 and an eccentric shaft portion 52. The first end of the eccentric shaft portion 52 is pivotally connected to the slider 24 of the double piston assembly 2, and the second end of the eccentric shaft portion 52 is connected to the main shaft portion 51. The main shaft portion 51 is coaxially connected to the motor shaft 41 of the motor 4, and the central axis of the eccentric shaft portion 52 is eccentric relative to the central axis of the motor shaft 41. The motor 4 drives the slider 24 to slide in the slide groove 231 through the crankshaft 5, thereby driving the first piston 221 to reciprocate in the first compression chamber 1021 through the piston frame 21 and driving the second piston 222 to reciprocate in the second compression chamber 1022.

[0127] The operation of the two-stage compressor according to the embodiment of the present invention is briefly described below.

[0128] The motor 4 drives the slider 24 to slide in the slide groove 231 through the crankshaft 5, driving the double piston assembly 2 to move upward, the first valve plate 801 opens and the second valve plate 802 closes, and the external air F passes through the air inlet 113, the air inlet channel 111, and the air inlet through hole 22111 in the first piston 221, and enters the first compression chamber 1021. When the double piston assembly 2 moves to the top dead center and turns to move downward, the air is compressed in the first compression chamber 1021, the first valve plate 801 is closed and the second valve plate 802 is opened, and the gas in the first compression chamber 1021 enters the second compression chamber 1022 through the connecting air channel 201. When the double piston assembly 2 moves to the bottom dead center and turns to move upward again, the air is compressed again in the second compression chamber 1022. Then, the exhaust valve 15 opens, and the compressed gas in the second compression chamber 1022 is discharged into the dryer 7 for drying, and the dried gas is discharged from the air outlet 71, for example, supplied to the compressed gas using device. This cycle repeats.

[0129] A two-stage compressor according to another embodiment of the present invention will be described below with reference to the accompanying drawings.

[0130] like Figure 19-Figure 23 As shown, the two-stage compressor 10012 includes a cylinder 1, a dual-piston assembly 2 and a drive device 9.

[0131] The cylinder body 11 has a first cylinder chamber 1011 and a second cylinder chamber 1012. The double piston assembly 2 may be the double piston assembly 2 of the above embodiment. The first piston 221 of the double piston assembly 2 is movably fitted in the first cylinder chamber 1011 and defines a first compression chamber 1021 in the first cylinder chamber 1011, the second piston 222 is movably fitted in the second cylinder chamber 1012 and defines a second compression chamber 1022 in the second cylinder chamber 1012, and the first compression chamber 1021 and the second compression chamber 1022 are connected through the connecting air passage 201.

[0132] like Figure 19-Figure 23 As shown, the driving device 9 includes a motor 4, a crankshaft 5 and a planetary reduction assembly 3. The motor 4 has a motor shaft 41, and the motor shaft 41 is rotatably connected to the slider 24 of the double piston assembly 2 through the planetary reduction assembly 3 and the crankshaft 5. The planetary reduction assembly 3 has a large reduction ratio, so that the motor 4 can be a high-speed motor, and the required space is small, reducing the overall volume and weight of the two-stage compressor 10012.

[0133] For example, the motor 4 may be a DC high-speed motor, and the speed of the motor 4 may be greater than 4000 rpm. Preferably, the speed of the motor 4 is greater than 8000 rpm. The high-speed motor has a small size, high speed, small torque, small moment of inertia, and fast start-stop response.

[0134] In the embodiment of the present invention, by adopting a combination of a high-speed motor and a planetary reduction assembly, the two-stage compressor can quickly respond to load changes, thereby ensuring the stability and accuracy of the response.

[0135] Compared with ordinary reducers, the planetary reduction assembly has a high transmission efficiency, which can not only reduce the power consumption required by the motor, thereby reducing the energy consumption of the secondary compressor, but also improve the working efficiency of the secondary compressor, and is especially suitable for automotive compressors.

[0136] like Fig.21 and Fig. 22 As shown, the motor 4 includes a motor shaft 41, a motor housing 42, a motor rear end cover 43, a rotor 44 and a stator 45. The rear end of the motor housing 42 has an opening, and the other end of the motor housing 42 is provided with a hole for the motor shaft 41 to pass through, and a rotor front bearing 46 is installed in the hole. The motor rear end cover 43 is detachably installed at the opening of the motor housing 42 by bolts, and a groove is provided on the motor rear end cover 43, and a rotor rear bearing 47 is installed in the groove. The motor shaft 41 is connected to the rotor 44, and the part of the motor shaft 41 that passes through the motor housing 42 cooperates with the rotor front bearing 46, and one end of the motor shaft 41 located in the motor housing 42 cooperates with the rotor rear bearing 47.

[0137] like Fig.21 and Fig. 22 As shown, the planetary reduction assembly 3 includes an inner gear ring 31, a planet carrier 32, a sun gear 33 and a plurality of planetary gears 34. The planetary gears 34 are rotatably mounted on the planet carrier 32 via a planetary gear shaft 35, the sun gear 33 is mounted on the motor shaft 41 of the motor 4, the inner gear ring 31 is connected to the motor housing 42 of the motor 4, the planetary gears 34 are respectively meshed with the sun gear 33 and the inner gear ring 31, and the crankshaft 5 is connected to the planet carrier 32.

[0138] The inner gear ring 31 is configured as a fixed gear of the planetary reduction assembly 3. The inner gear ring 31 includes a cylinder 311 and an annular boss 312. The annular boss 312 is disposed on the inner peripheral wall of the cylinder 311. Internal teeth are formed on the inner peripheral wall surface of the annular boss 312. The annular boss 312 defines a matching hole 301 in the cylinder 311. The matching hole 301 is located at one end of the cylinder 311 close to the motor 4. The end of the motor housing 42 is provided with a matching portion 401 with a reduced diameter. The matching portion 401 is matched in the matching hole 301. One end of the cylinder 311 is butted with one end of the motor housing 42. The outer peripheral surface of the cylinder 311 is flush with the outer peripheral surface of the motor housing 42.

[0139] Through the close fit between the matching hole 301 and the matching part 401, the distance between the planetary reduction assembly 3 and the motor 4 is reduced, the compactness of the structure is improved, the volume and the occupied space are reduced, and the volume of the secondary compressor 10012 can be further reduced. In addition, the outer peripheral surface of the cylinder 311 is flush with the outer peripheral surface of the motor housing 42, which also improves the overall visual effect. Further, a sealing ring 48 or other sealing elements can be provided between the matching hole 301 and the matching part 401 to improve the sealing between the planetary reduction assembly 3 and the motor 4.

[0140] like Fig. 22 As shown, the end face ( Fig. 22 An assembly groove 321 is provided on the middle right end surface, and a rear bearing 322 is installed in the assembly groove 321. One end of the motor shaft 41 extending out of the motor housing 42 cooperates with the rear bearing 322.

[0141] The motor shaft 41 drives the sun gear 33 to rotate around the central axis X1. The central axis X1 is the central axis of the motor shaft 41, the sun gear 33 and the planet carrier 32. The planet gear 34 revolves around the central axis X1 and rotates around the central axis of the planet gear shaft 35, so that the planet carrier 32 rotates around the central axis X1.

[0142] Preferably, the teeth of the inner ring gear 31 and the planetary gear 34 are helical teeth, so as to reduce speed, increase torque and reduce noise.

[0143] like Figure 21-23 As shown, the crankshaft 5 includes a main shaft portion 51 and an eccentric shaft portion 52. One end of the main shaft portion 51 is connected to the planet carrier 32. The central axis of the main shaft portion 51 is coaxial with the central axis X1 of the planet carrier 32, the inner gear ring 31 and the motor shaft 41, which is referred to as the central axis X1 in the following description. The cylinder block 11 is provided with a front bearing 112, and the main shaft portion 51 cooperates with the front bearing 112.

[0144] Preferably, the main shaft portion 51 and the planetary carrier 32 can be formed integrally, thereby improving the overall strength and durability of the crankshaft 5, while also reducing the workload of assembling and maintaining the crankshaft 5, and improving the compactness of the structure, reducing the volume and occupied space, and further reducing the volume of the secondary compressor 10012.

[0145] The main shaft portion 51 is provided with an assembly hole 511, one end of the eccentric shaft portion 52 is fitted in the assembly hole 511, the other end of the eccentric shaft portion 52 extends out from the assembly hole 511, the center axis X2 of the eccentric shaft portion 52 is eccentric relative to the center axis X1 of the main shaft portion 51, and the other end of the eccentric shaft portion 52 is fitted with the bearing 25 in the piston frame 21.

[0146] Since the double-piston assembly 2 and the eccentric shaft portion 52 are eccentrically arranged relative to the main shaft portion 51, the crankshaft 5 will generate an unbalanced force when rotating. For this reason, a balancing block 53 is provided on the main shaft portion 51 to reduce or eliminate the vibration caused by the imbalance of the crankshaft 5, improve the stability and reliability of the operation of the crankshaft 5, and reduce the noise generated by the vibration of the crankshaft 5.

[0147] The vehicle according to the embodiment of the present invention will be described below with reference to the accompanying drawings.

[0148] like Fig.24 As shown, the vehicle 100 of the embodiment of the present invention includes a pneumatic device 1002 and a secondary compressor 10012. The secondary compressor 10012 may be the secondary compressor 10012 of the above-mentioned embodiment. The secondary compressor 10012 is connected to the pneumatic device 1002 and is used to supply compressed air to the pneumatic device 1002. For example, the pneumatic device 1002 may be an air spring of an air suspension system of the vehicle 100.

[0149] The vehicle of the embodiment of the present invention has a two-stage compressor with a compact structure, small size, light weight, miniaturization, and high applicability, thereby effectively solving the problems of large size and slow starting response of vehicle compressors in related technologies. Therefore, the two-stage compressor of the embodiment of the present invention can provide a more efficient, compact and reliable air supply solution for the vehicle's air suspension system.

[0150] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0151] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0152] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0153] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0154] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0155] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A dual piston assembly, characterized in that: include: A piston frame, wherein the piston frame has a mounting groove; a first piston and a second piston, wherein the first piston and the second piston are connected to each other through the piston holder; A bushing, the bushing is installed in the installation groove, the bushing has a slide groove therein, and the slide groove has a first guide surface and a second guide surface which are parallel to each other and face each other in a first direction; A slider is fitted in the slide groove, the slider is movable in the slide groove along a second direction orthogonal to the first direction and is guided by the first guide surface and the second guide surface.

2. The dual piston assembly according to claim 1, characterized in that: The dual piston assembly further includes a bearing mounted within the slider.

3. The dual piston assembly according to claim 2, characterized in that: The dual-piston assembly also includes a bearing seat, which is a metal bearing seat and is installed in the slider, the bearing is installed in the bearing seat, and an anti-rotation structure is provided between the slider and the bearing seat to prevent the bearing seat from rotating relative to the slider.

4. The dual piston assembly according to claim 1, characterized in that: The bushing includes a first bushing body and a second bushing body, the first bushing body and the second bushing body are connected along the first direction, a first elastic member for pressing the first bushing body toward the second bushing body is provided between the first bushing body and the piston frame, and a second elastic member for pressing the second bushing body toward the first bushing body is provided between the second bushing body and the piston frame.

5. The dual piston assembly according to claim 4, characterized in that: The bushing has a first outer surface and a second outer surface, the first outer surface is provided with a first groove, the second outer surface is provided with a second groove, the first elastic member is arranged in the first groove, the second elastic member is arranged in the second groove, and the first elastic member and the second elastic member are corrugated plates or arc plates.

6. The dual piston assembly according to claim 1, characterized in that: The slider has a first working surface and a second working surface that are opposite to each other in the first direction, the first working surface is in sliding contact with the first guide surface, and the second working surface is in sliding contact with the second guide surface.

7. The dual piston assembly according to claim 1, characterized in that: The slider has a first working surface and a second working surface opposite to each other in the first direction, a plurality of first rolling members are arranged between the first working surface and the first guide surface, a plurality of second rolling members are arranged between the second working surface and the second guide surface, the first working surface is provided with a first accommodating groove for accommodating the first rolling member, and the second working surface is provided with a second accommodating groove for accommodating the second rolling member.

8. The dual piston assembly according to claim 1, characterized in that: The wear coefficient of the bushing is smaller than the wear coefficient of the slider.

9. The dual piston assembly according to claim 1, characterized in that: The first guide surface and the second guide surface are provided with a wear-resistant coating.

10. The dual piston assembly according to claim 1, characterized in that: The bushing is made of metal, and the slider is made of a polytetrafluoroethylene-based composite material or a polyetheretherketone-based composite material.

11. The dual piston assembly according to any one of claims 1 to 10, characterized in that: At least one of the first piston and the second piston is provided with a valve plate, the valve plate includes a plate body, the plate body is provided with a slot, the slot penetrates the plate body along the thickness direction of the plate body, the slot divides the plate body into a sealing portion, a mounting portion and a plurality of swing arms, the sealing portion and the mounting portion are concentric with each other, the mounting portion is arranged around the sealing portion, the first end of the swing arm is connected to the sealing portion, and the second end of the swing arm is connected to the mounting portion, wherein when the number of the swing arms is an even number, the plurality of swing arms are arranged in pairs, and the two swing arms in the same pair of swing arms are centrally symmetrical to each other relative to the center of the sealing portion, wherein when the number of the swing arms is an odd number, the plurality of swing arms are evenly arranged around the center of the sealing portion along the circumference of the sealing portion.

12. The dual piston assembly according to claim 11, characterized in that The sealing portion is circular, the mounting portion is annular, the swing arm is arc-shaped, there are two swing arms and they are centrally symmetrical with each other relative to the center of the sealing portion, there are two slots, each slot includes an arc-shaped outer slot segment, an arc-shaped inner slot segment and a connecting slot segment connected between the outer slot segment and the inner slot segment, one swing arm is located between the outer slot segment of one slot and the inner slot segment of another slot, and the other swing arm is located between the inner slot segment of the one slot and the outer slot segment of the other slot.

13. The dual piston assembly according to claim 11, characterized in that: The sealing portion is circular, the mounting portion is annular, the swing arm is arc-shaped, there are three swing arms and they are evenly arranged around the center of the sealing portion along the circumference of the sealing portion, there are three slots, each slot includes an arc-shaped outer slot segment, an arc-shaped inner slot segment and a connecting slot segment connected between the outer slot segment and the inner slot segment, and each swing arm is located between the outer slot segment of one slot and the inner slot segment of another slot.

14. A two-stage compressor, characterized in that: include: a cylinder having a first compression chamber and a second compression chamber; A double piston assembly, wherein the double piston assembly is a double piston assembly according to any one of claims 1 to 13, wherein the first piston is movably disposed in the cylinder for compressing gas in the first compression chamber, the second piston is movably disposed in the cylinder for compressing gas in the second compression chamber, and the first compression chamber and the second compression chamber are connected via a connecting air passage that runs through the piston frame, the first piston and the second piston; A driving device is connected to the slider and is used to drive the slider to slide in the slide groove.

15. The two-stage compressor according to claim 14, characterized in that The driving device includes a motor and a crankshaft, the motor has a motor shaft, the crankshaft includes a main shaft portion and an eccentric shaft portion, the first end of the eccentric shaft portion is rotatably connected to the slider, the second end of the eccentric shaft portion is connected to the main shaft portion, the main shaft portion is coaxially connected to the motor shaft, and the central axis of the eccentric shaft portion is eccentric relative to the central axis of the motor shaft.

16. The two-stage compressor according to claim 15, characterized in that The driving device further comprises a planetary reduction assembly, and the motor shaft is connected to the main shaft portion via the planetary reduction assembly.

17. The two-stage compressor according to claim 16, characterized in that The planetary reduction assembly includes an inner ring gear, a planet carrier, a sun gear and a plurality of planetary gears, the planetary gears are rotatably mounted on the planet carrier via planetary gear shafts, the sun gear is mounted on the motor shaft, the inner ring gear is connected to the motor housing of the motor, the planetary gears are respectively meshed with the sun gear and the inner ring gear, the main shaft portion is connected to the planet carrier, and the central axis of the main shaft portion is coaxial with the central axis of the planet carrier, the central axis of the inner ring gear and the central axis of the motor shaft.

18. The two-stage compressor according to claim 17, characterized in that The planet carrier is formed integrally with the main shaft portion. An assembly hole is provided at one end of the main shaft portion, and the second end of the eccentric shaft portion is fitted in the assembly hole.

19. The two-stage compressor according to claim 15, characterized in that The motor is a DC motor, and the rotation speed of the motor is greater than 4000 rpm.

20. A vehicle, characterized in that: include: A pneumatic device and a two-stage compressor according to any one of claims 14 to 19, wherein the two-stage compressor is connected to the pneumatic device and is used to supply compressed air to the pneumatic device.

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