Air compressor

Abstract

The application provides an air compressor, which comprises: an air tank for storing compressed air; a shell; a compression unit accommodated in the shell for compressing air sucked from outside and supplying the air to the air tank; the compression unit comprises a cylinder and a piston arranged in the cylinder and in sliding fit with the cylinder; a driving unit for driving the piston, the driving unit comprises a motor and a transmission mechanism, the motor is provided with a rotating shaft, the transmission mechanism is used for converting the rotating motion of the rotating shaft into the reciprocating motion of the piston for compressing air, the motor is a two-stage induction motor, the inner diameter of the cylinder ranges from 67.7 mm to 72.7 mm, and the stroke of the piston ranges from 13 mm to 20 mm; so that the air charging time of the air compressor is not more than 70 seconds. The air charging efficiency, cost and service life of the air compressor reach a better balance.

Description

Technical Field

[0001] This invention relates to an air compressor. Background Technology

[0002] The working principle of an air compressor typically involves a motor driving an eccentric transmission mechanism. This mechanism converts the motor's rotational motion into reciprocating motion of a piston, causing a change in cylinder volume. Due to the pressure change within the cylinder, air enters through the intake port, passing through an air filter (muffler). During the compression stroke, as the cylinder volume decreases, the compressed air passes through the exhaust valve, exhaust pipe, and one-way valve into the air tank. When the exhaust pressure reaches the rated pressure, a pressure switch automatically shuts off the compressor. When the air tank pressure drops to the preset pressure, the pressure switch automatically reconnects and restarts the compressor.

[0003] Currently, most air compressors on the market, labeled as having a 30L air tank, typically have a filling time of over 130 seconds, requiring a long waiting period to refill the air tank with compressed air. This affects the user's work efficiency.

[0004] Therefore, it is necessary to develop a new air compressor to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an air compressor with short air intake time and high working efficiency.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is: an air compressor, the air compressor comprising: an air tank for storing compressed air; a housing; a compression unit housed within the housing for compressing air drawn in from the outside and supplying air to the air tank; the compression unit comprising a cylinder and a piston disposed within the cylinder and slidingly engaged with the cylinder; a drive unit for driving the piston, the drive unit comprising a motor and a transmission mechanism, the motor having a rotating shaft, the transmission mechanism for converting the rotational motion of the rotating shaft into the reciprocating motion of the piston for compressing air, the motor being a two-stage induction motor, the inner diameter of the cylinder ranging from 67.7mm to 72.7mm, and the piston stroke ranging from 13mm to 20mm; thereby ensuring that the air compressor's air intake time is no more than 70 seconds.

[0007] Preferably, the inner diameter of the cylinder is in the range of 67.7mm to 72.7mm, and the piston stroke is in the range of 14mm to 20mm; the air compressor's air supply time is no more than 65 seconds.

[0008] Preferably, the inner diameter of the cylinder is in the range of 69.7mm to 72.7mm, and the piston stroke is in the range of 13mm to 20mm; the air compressor's air supply time is no more than 60 seconds.

[0009] Preferably, the inner diameter of the cylinder is in the range of 69.7mm to 72.7mm, and the piston stroke is in the range of 14mm to 20mm; the air compressor's air supply time is no more than 55 seconds.

[0010] Preferably, the piston includes a cup, and the cup is made of polytetrafluoroethylene.

[0011] Preferably, the cylinder is made of ceramic-plated aluminum, chrome-plated steel, or anodized aluminum.

[0012] Preferably, one end of the cylinder abuts against a valve plate, and the minimum gap between the valve plate and the piston is defined as the top gap, which ranges from 0.2mm to 0.8mm.

[0013] Preferably, the top gap ranges from 0.4 mm to 0.6 mm.

[0014] Preferably, one end of the cylinder abuts against a valve plate, the valve plate including a first side facing the piston, a groove provided on the first side for receiving an intake valve plate, the intake valve plate being completely received in the groove, and the distance between the valve plate and the first side is in the range of 0.5mm-0.7mm.

[0015] Preferably, one end of the cylinder abuts against a valve plate, and the valve plate has an intake valve plate on the side facing the piston. The piston includes a cup and a cup pressure plate connecting the cup to the transmission mechanism. The cup pressure plate has a recess that at least partially accommodates the intake valve plate, and the depth of the recess is in the range of 0.5mm-1mm.

[0016] Preferably, the air compressor includes two compression units.

[0017] Preferably, the housing includes a support portion for housing the compression unit, and a cylinder head is provided at the upper end of the support portion. The cylinder head is provided with an air inlet and an air outlet.

[0018] Preferably, the housing includes a support portion for housing the compression unit, the upper end of the support portion is provided with a cylinder head, the support portion has an upper end near the cylinder head and a lower end opposite to it, and an air outlet is provided at the upper end.

[0019] Another technical solution of the present invention to solve the above-mentioned technical problem is: an air compressor, the air compressor comprising: an air tank for storing compressed air; a housing; a compression unit housed within the housing for compressing air drawn in from the outside and supplying air to the air tank; the compression unit comprising a cylinder and a piston disposed within the cylinder and slidingly engaged with the cylinder; a drive unit for driving the piston, the drive unit comprising a motor and a transmission mechanism, the motor having a rotating shaft, the transmission mechanism for converting the rotational motion of the rotating shaft into the reciprocating motion of the piston for compressing air, the motor being a two-stage induction motor, the inner diameter of the cylinder ranging from 65.7 mm to 72.7 mm, and the piston stroke ranging from 14 mm to 20 mm; thereby ensuring that the air compressor's air intake time is no more than 70 seconds.

[0020] The air compressor of the present invention, by employing a two-stage induction motor, matches the rotational speed with the cylinder inner diameter and piston stroke, which can improve the air intake efficiency without affecting the lifespan of the air compressor, and at the same time, does not significantly increase the cost of the whole machine, thus achieving a good balance between efficiency, cost and lifespan. Attached Figure Description

[0021] Figure 1 This is a three-dimensional schematic diagram of the air compressor of the present invention.

[0022] Figure 2 for Figure 1 The diagram shows a partial exploded view of the air compressor.

[0023] Figure 3 for Figure 1 The diagram shows a partial cross-sectional view of the air compressor.

[0024] Figure 4 for Figure 1 The diagram shows a partial three-dimensional representation of an air compressor.

[0025] Figure 5 for Figure 1 The diagram shows a partial cross-sectional view of the air compressor.

[0026] Figure 6 for Figure 5 Enlarged view of a portion of the image.

[0027] Figure 7a and 7b The images show the front view and sectional view of the leather cup pressing plate.

[0028] Figure 8 for Figure 1 The diagram shows a comparison of the cylinder inner diameter, piston stroke, and air intake time of an air compressor. Detailed Implementation

[0029] The air compressor involved in this embodiment can be single-cylinder or multi-cylinder, and is not limited to a two-cylinder compressor. The following description uses a two-cylinder compressor as an example.

[0030] Please see Figure 1 The air compressor 30 includes a housing 32, an air tank 34 for storing compressed air, a compression unit 36 ​​housed within the housing 32, and a drive unit 38 for driving the compression unit 36. The compression unit 36 ​​compresses air drawn in from the outside and supplies the air to the air tank 34. In the following description, it is assumed that the air compressor 30 is located in the orientation in which it will be used, and the terms "upward," "downward," "upper," "lower," "above," "below," "below," "right," "left," "front," "rear," and similar terms are used. More specifically, Figure 1 The left, right, top, and bottom sides of the image are the front, rear, top, and bottom sides of the air compressor 30.

[0031] Compressed air discharged from compression unit 36 ​​enters air tank 34 through exhaust valve 31, exhaust pipe 33, and one-way valve 35 (check valve). Air tank 34 is designated as a 30L air tank, meaning it can store approximately 30L of compressed air. Air tank 34 has a hollow cylindrical structure extending along its longitudinal axis. In other words, air tank 34 extends in a front-to-back direction. Air tank 34 has a closed axial end.

[0032] The gas tank 34 has a top on which a pair of supports 42 are provided for connecting the outer casing 32. The gas tank 34 has a front end of the top and a rear end of the top, with a handle 40 at the front end and an auxiliary handle 41 at the rear end of the top.

[0033] The air tank 34 has a front bottom and a rear bottom. A shock-absorbing rubber support 44 is located at the front bottom, and a pair of wheels 46 are located at the rear bottom. The shock-absorbing rubber support 44 and the pair of wheels 46 are respectively located at the three corners of the air compressor 30. When the air compressor 30 is installed on the ground, the shock-absorbing rubber support 44 and the pair of wheels 46 can contact the ground to support the air compressor 30. When it is necessary to move the air compressor 30, simply pull the handle 40; the shock-absorbing rubber support 44 will move away from the ground, leaving only the wheels 46 in contact with the ground, thus allowing the air compressor 30 to be moved easily.

[0034] In the above embodiment, one shock-absorbing rubber support 44 and a pair of wheels 46 are provided. However, two shock-absorbing rubber supports 44 and one wheel can also be provided; or two shock-absorbing rubber supports 44 and two wheels 46 can be provided, in which case the two rubber supports 44 and the two wheels 46 are located at the four corners of the air compressor 30. When the air compressor 30 is installed on the ground, the two rubber supports 44 and the two wheels 46 can contact the ground to support the air compressor 30.

[0035] See also Figure 1 The air tank 34 is also equipped with a pressure switch 45, which is used to control the air compressor 30 to turn on or off.

[0036] Compressed air at a rate of 6 to 10 kg / cm² is supplied to the air tank 34 via the exhaust pipe 33. The air tank 34 is provided with several air outlets (not shown), which are connected to a connector 43 via a pressure reducing valve (not shown) for supplying air to pneumatic tools. The pressure reducing valve has a preset maximum compressed air pressure at the outlet side, which is connected to a check valve 3. 5 Regardless of the pressure of the compressed air, in this embodiment, the maximum pressure in the pressure reducing valve is selected from a predetermined value ranging from 6 to 8 kg / cm². Therefore, the compressed air obtained from the air outlet of the pressure reducing valve is independent of the pressure in the air tank 34 and can be selected as needed, generally equal to or lower than the maximum pressure.

[0037] The gas storage tank 34 is also equipped with a pressure gauge (not shown), which is used to monitor the pressure of the compressed air in the gas storage tank 34.

[0038] Safety valve 47 is installed on gas tank 34. When the pressure in gas tank 34 increases abnormally, safety valve 47 ensures safety by allowing some air to escape to the outside.

[0039] The crankshaft rotates, driving the connecting rod to reciprocate the piston, causing a change in cylinder volume. Due to this pressure change within the cylinder, air is forced into the cylinder through the intake valve and air filter (muffler). During the compression stroke, as the cylinder volume decreases, compressed air passes through the exhaust valve, exhaust pipe, and one-way valve (check valve) into the air tank. When the exhaust pressure reaches the rated pressure, a pressure switch automatically shuts off the engine. When the air tank pressure drops to a certain level, the pressure switch automatically reconnects and restarts the engine.

[0040] Further, please see Figure 1The air storage tank 34 is equipped with a drainage device. The drainage device includes a drain outlet 48 and a drain switch 50 on the air storage tank 34. The user can manually operate the drain switch 50 to selectively open and close the drain switch 50. When the drain switch 50 is open, the wastewater and compressed air stored in the air storage tank 34 can be released from the drain outlet 48.

[0041] Please see Figure 2 and Figure 3 A drive unit 38 for driving the compression unit 36 ​​is located above the air tank 34. The drive unit 38 is located approximately at the center of the air compressor 30 in the front / rear direction. The drive unit 38 includes a motor 52 and a transmission mechanism 54. The motor 52 includes a stator 56, a rotor 58, and a rotating shaft 60 connected to the rotor 58. The axis X of the rotating shaft 60 is oriented in the front / rear direction and is parallel to the extension direction of the air tank 34. Fans 62 are mounted at both ends of the rotating shaft 60 for cooling the motor 52 and the compression unit 36.

[0042] Specifically, the fan 62 is fixed to the rotating shaft 60 by pressing, bonding, or fitting, but the method of fixing is not limited to this. The rotation of the motor 52 drives the fan 62 to rotate around the axis X, thereby cooling the motor 52 and the compressor unit 36.

[0043] The motor 52 can be powered by either an AC or DC power source. In this embodiment, an AC power source is used, and the power cord and related circuitry are omitted from the accompanying drawings.

[0044] The transmission mechanism 54 includes a crank 64 and a connecting rod 66. Specifically, the crank 64 includes a connecting hole 68 and a connecting boss 70. The connecting hole 68 is disposed through the connecting boss 70, and the center of the connecting hole 68 and the center of the connecting boss 70 are offset. The crank 64 is fixedly connected to the rotating shaft 60 through the connecting hole 68.

[0045] The connecting rod 66 includes connecting plates 72 and connecting rings 74 located at both ends. The connecting rings 74 are sleeved on the connecting boss 70 via bearings 76. Specifically, the inner ring of the bearing 76 is interference-fitted onto the upper connecting boss 70; the connecting rings 74 are interference-fitted onto the outer ring of the bearing 76.

[0046] The crank 64 also includes a balance block 78. The center of gravity of the balance block 78, the center of gravity of the connecting boss 70, and the center of the connecting hole 68 are located on the same straight line. The center of the balance block 78 and the center of the connecting boss 70 are located on both sides of the center line of the connecting hole 68. The distance between the center of the balance block 78 and the center line of the connecting hole 68 is greater than the distance between the center of the connecting boss 70 and the center line of the connecting hole 68, so that the lighter balance block 78 can better balance the force exerted on the connecting boss 70 by the connecting rod 66, thereby reducing bearing wear.

[0047] In this embodiment, cranks 64 are fixedly connected to both ends of the rotating shaft 60. The rotation strokes of the two cranks 64 differ by 180°. The balance blocks 78 on the cranks 64 at both ends of the rotating shaft 60 are symmetrically distributed with the center of the motor 52 as the center of symmetry. The motor 52, together with the two symmetrically distributed balance blocks 78, can make the rotation more balanced.

[0048] See also Figure 2 and Figure 3 The housing 32 includes two fixed portions 80 and two supporting portions 82. In this embodiment, both fixed portions 80 extend along the axis X of the rotation shaft 60 and are fixedly connected by screws 79, serving to accommodate at least a portion of the motor 52. Specifically, the rotation shaft 60 of the motor 52 is rotatably supported on the two fixed portions 80 by bearings 84, and the two cranks 66 and the two fans 62 are respectively accommodated within the fixed portions 80. A fan cover 81 is fitted onto the end of the fixed portion 80 near the fan 62 to guide the entry of cooling air and prevent contact with the fan 62. The two fixed portions 80 are respectively mounted on a pair of brackets 42 on the air tank 34 by fastening devices.

[0049] The two support parts 82 are integrally formed with the two fixing parts 80. Here, integral formation can be understood as at least the connection between materials, such as welding, bonding, injection molding, etc.; or integral molding, such as being formed from a single casting, etc.

[0050] Please see Figure 4 The fan shroud 81 has several air inlets (unlabeled) along the X-axis of the rotating shaft 60. The fixed part 80 has an air outlet 83 at its far end, away from the fan 62, and the support part 82 has an air outlet 85 at its far end, away from the fixed part 80. When the motor 52 runs, the fan 62, mounted on the rotating shaft 60, generates an airflow substantially parallel to the X-axis of the rotating shaft 60. This airflow draws in ambient air through the air inlets on the fan shroud 81. As shown by the arrows in the figure, due to the action of the fan 62, the cool air flowing parallel to the axis through the fan shroud 81 axially flows into the fixed part 80 along both ends of the rotating shaft 60. A portion of the cool air flows through the transmission mechanism 54 to the stator 56 and rotor 58 to absorb heat energy, and the hot air is then discharged through the air outlet 83 at its far end, away from the fan 62. Another portion of the cool air flows through the transmission mechanism 54 to the compression unit to absorb heat energy, and the hot air is then discharged through the air outlet 85 on the support part 82. The air outlet 85 is located at a distance from the fixed part 80, so that the compression unit 36 ​​can be cooled better.

[0051] In order to increase the cooling effect, there is also a gap between the fixed part 80 and the motor 52. Specifically, there is a gap between the fixed part 80 and the stator 56, and a portion of the cold air flows in the gap to absorb heat energy and cool the motor 52.

[0052] In this embodiment, the drive unit 38 simultaneously drives two compression units 36. Both support portions 82 extend along an axis X perpendicular to the rotation axis 60 and are used to accommodate the two compression units 36. Please continue to the next section. Figure 2 and Figure 3 The compression unit 36 ​​includes a cylinder 86 housed within a support portion 82 and a piston 88 disposed within the cylinder 86 and slidingly engaged with it. The piston 88 is connected to a connecting plate 72 and is driven by a connecting rod 66 to reciprocate within the cylinder 86. Because the rotational strokes of the two cranks 64 differ by 180°, the reciprocating inertial forces derived from the reciprocating motion of the pistons 88 within the two cylinders 86 are exactly opposite, reducing vibration and noise, thereby achieving the best vibration reduction effect for the air compressor.

[0053] In this embodiment, the piston 88 includes a cup 87 and a cup pressure plate 89 connecting the cup 87 to the transmission mechanism 54. Specifically, the cup 89 is mounted on a connecting plate 72 via the cup pressure plate 89, and the connecting plate 72 is located at the tail end of the connecting rod 66. The cup 87 is made of a high-molecular wear-resistant material, such as polytetrafluoroethylene. The cylinder 86 is made of materials such as ceramic-plated aluminum, chrome-plated steel, or anodized aluminum, which ensures both longevity and good heat dissipation.

[0054] Two valve plates 90 are connected to each of the two support sections 82. (See also...) Figure 2 and Figure 3 Specifically, the support portion 82 has a receiving groove 92 corresponding to the cylinder 86, and the valve plate 90 has a positioning groove 94 corresponding to the cylinder 86. The valve plate 90 has a through hole 98, and the four corners of the top of the support portion 82 have threaded holes 100. The valve plate 90 and the support portion 82 are fixedly connected by screws. Thus, when the valve plate 90 is fixed to the support portion 82, the cylinder 86 is also installed in the receiving groove 92 of the support portion 82. Of course, to ensure better sealing of the cylinder 86, a sealing ring 96 is also provided between the positioning groove 94 and the cylinder 86.

[0055] The air compressor 30 also includes a cylinder head 102, which is connected to both valve plates 90. (See also...) Figure 2 and Figure 5 The cylinder head 102 and the valve plate 90 are connected to form an intake chamber 101a and an exhaust chamber 101b (only one cylinder head is shown). In this embodiment, both cylinder heads 102 are provided with an intake port 103a that communicates with the intake chamber 101a and an exhaust port 103b that communicates with the exhaust chamber 101b.

[0056] Of course, in order to improve the sealing of the intake chamber 101a and the exhaust chamber 101b, a seal 99 is also provided between the cylinder head 102 and the valve plate 90.

[0057] Specifically, an air filter (muffler) 105 is also installed on the air inlet 103a, which can effectively filter and reduce noise. The air outlet 103b is connected to the exhaust pipe 33 through the exhaust valve 31, and the compressed air is stored in the air tank 34.

[0058] Combined Figure 2 and Figure 6 The valve plate 90 is provided with an intake valve hole 104 corresponding to the intake chamber 101a, an exhaust valve hole 106 corresponding to the exhaust chamber 101b, and an intake valve plate 108 and an exhaust valve plate 110 for correspondingly controlling the air passage of the intake valve hole 104 and the exhaust valve hole 106.

[0059] The valve plate 90 has a first side 107a facing the piston 88 and a second side 107b facing away from the piston 88. An intake valve plate 108 is mounted on the first side 107a, and an exhaust valve plate 110 is mounted on the second side 107b.

[0060] A first fixing hole 114 for screw 112 connection is provided on the exhaust valve plate 110, and a threaded hole 116 for screw 112 connection is provided on the second side 107b of the valve plate 90. The screw 112 passes through the through hole on the valve plate pressure plate 111b, and engages with the first fixing hole 114 and threaded hole 116 on the exhaust valve plate 110, thus mounting the exhaust valve plate 110 on the second side 107b. A second fixing hole 115 for screw 113 connection is provided on the intake valve plate 108, and a threaded hole 117 for screw 113 connection is provided on the first side 107a of the valve plate 90. The screw 113 passes through the through hole on the valve plate pressure plate 111a, and engages with the second fixing hole 115 and threaded hole 117 on the intake valve plate 108, thus mounting the intake valve plate 108 on the first side 107a.

[0061] In this embodiment, the stroke range of piston 88 is 13mm-20mm.

[0062] To prevent the piston 88 from directly impacting the valve plate 90, a certain gap must be maintained between the valve plate 90 and the piston 88. This minimum gap can be defined as the head clearance. In this embodiment, the head clearance is the minimum gap between the first side 107a of the valve plate 90 and the pressure cup plate 89. A larger head clearance will prevent the compressed air from being effectively discharged, thus affecting working efficiency; while a smaller head clearance can easily lead to cylinder collision accidents. To improve working efficiency and avoid cylinder collision accidents, the head clearance can be controlled within the range of 0.2mm-0.8mm. Of course, the head clearance range can also be 0.4mm-0.6mm; or 0.5mm-0.6mm, etc.

[0063] In another embodiment, to avoid cylinder head collision, a groove 109 can be provided on the first side surface 107a. This groove 109 is used to accommodate the intake valve plate 108, which is completely accommodated within the groove 109, and the distance between the intake valve plate 108 and the first side surface 107a is in the range of 0.5mm-1mm. Of course, the distance between the intake valve plate 108 and the first side surface 107a can also be in the range of 0.5mm-0.7mm.

[0064] In another embodiment, to avoid cylinder head collisions. See also Figure 7a and 7b The pressure plate 89 has a recess 118 that at least partially accommodates the intake valve plate 108, and the depth of the recess 118 ranges from 0.5mm to 1mm. Of course, the depth of the recess 118 can also range from 0.5mm to 0.7mm.

[0065] In another embodiment, an air pipe can be provided between the two cylinder heads 102 to connect the two intake chambers 101a, and an air pipe can be provided to connect the two outlet chambers 101b of the two cylinder heads 102. Thus, one cylinder head 102 has an intake port 103a connecting to the intake chamber 101a, and the other cylinder head 102 has an outlet port 103b connecting to the outlet chamber 101b. That is, the twin-cylinder air compressor can also have only one intake port and one outlet port.

[0066] The air compression operation of the air compressor 30 will now be described based on the above-described structure. (See also...) Figure 2 , Figure 3 and Figure 6When the motor 52 starts, it drives the two cranks 64 to rotate eccentrically, which causes the two connecting rods 66 to reciprocate in their respective cylinders 86. Since the rotation strokes of the two cranks 64 differ by 180°, the pistons 88 in the two cylinders 86 reciprocate in exactly opposite directions. If the piston 88 in one of the two cylinders 86 moves downward, i.e., closer to the rotation axis 60, the pressure in this cylinder is lower than that in the intake chamber 101a. The corresponding intake valve 108 opens, allowing air to enter through the intake port 103a of the cylinder head 102 and then into the cylinder 86 via the intake chamber 101a. Meanwhile, the piston 88 in the other cylinder moves upward, i.e., away from the rotation axis 60. This compresses the air until the pressure in the cylinder 86 is much higher than that in the exhaust chamber 101b. At this point, the corresponding exhaust valve 110 opens, allowing air to enter the exhaust chamber 101b and exit through the corresponding exhaust port 103b of the cylinder head 102. The compressed air is then stored in the air tank 34 via the exhaust pipe 33. This process continues, with the pistons 88 in the two cylinders 86 alternately compressing air and storing it in the air tank 34.

[0067] Currently, most air compressors on the market use a four-stage induction motor with a speed of 1400 rpm, a piston stroke of 13mm-18mm, and a cylinder inner diameter of 63.7mm. The air intake time is usually over 130 seconds. See Table 1 for details.

[0068] Table 1:

[0069]

[0070] The table above lists several mainstream air compressors on the market. Theoretically, for oil-free air compressors, with a fixed air tank capacity, the higher the compressor speed, the larger the discharge volume and the higher the air intake efficiency. However, simply increasing the compressor speed does not guarantee improved air intake efficiency. The cylinder bore, piston stroke, compressor lifespan, and cost must also be considered. The reason why most air compressors on the market use four-pole induction motors instead of two-pole ones is that simply increasing the speed without considering the cylinder bore and piston stroke for matching will not necessarily improve air intake efficiency and may even lead to compressor burnout. Only when the cylinder bore, piston stroke, and motor speed are matched can a good balance be achieved between efficiency, cost, and lifespan. See Table 2 for details.

[0071] Table 2:

[0072]

[0073]

[0074] In Table 2, taking a 2840 rpm secondary induction motor as an example, and defining the air compressor's piston stroke as 13 mm and cylinder inner diameter as 63.7 mm, the overall cost is C, and the volume is L. (Refer to...) Figure 8 As shown in Table 2, the overall lifespan of the air compressor is 900 hours or more, meeting the standards. However, when the piston stroke is 22mm, the overall cost increases by approximately 1.5 times, and the volume increases by approximately 1.2 times. Therefore, while a piston stroke of 22mm or more results in a shorter air intake time, the cost is too high and the volume is too large. For different piston strokes, a cylinder inner diameter of 74.7mm significantly increases the overall cost. Thus, a cylinder inner diameter of 74.7mm or more offers lower cost-effectiveness. Conversely, a cylinder inner diameter or stroke that is too small will result in very low air intake efficiency. Only when the speed, inner diameter, and stroke are matched can air intake efficiency be improved without affecting the lifespan of the air compressor or excessively increasing the overall cost, thus achieving a better balance between efficiency, cost, and lifespan.

[0075] For a two-stage induction motor (speed between 2700 rpm and 3000 rpm), with a piston stroke of 13mm-20mm and a cylinder inner diameter of 67.7mm-72.7mm, the air intake time is typically no more than 70 seconds. This results in high air intake efficiency, effectively meeting the required specifications. Furthermore, costs can be kept within a reasonable range.

[0076] Of course, for a two-stage induction motor (speed between 2700 rpm and 3000 rpm), the piston stroke range can be 14 mm to 20 mm; the cylinder inner diameter range can be 65.7 mm to 72.7 mm, and the air intake time can be no more than 70 seconds.

[0077] As shown in the table above, for a two-stage induction motor (speed between 2700 rpm and 3000 rpm), with a piston stroke of 14 mm to 20 mm and a cylinder inner diameter of 67.7 mm to 72.7 mm, the air intake time is typically no more than 65 seconds. This results in high air intake efficiency, effectively meeting the required specifications. Furthermore, costs can be kept within a reasonable range.

[0078] The piston stroke can also be 13mm-20mm, and the cylinder inner diameter is 69.7mm-72.7mm, so the intake time is usually no more than 60 seconds.

[0079] The piston stroke can also be 14mm-20mm, and the cylinder inner diameter is 69.7mm-72.7mm, so the intake time is usually no more than 55 seconds.

[0080] As shown in Table 1, the air intake method (single intake, single output) of the air compressor has a slight impact on the air intake efficiency. Therefore, Table 2 only lists dual intake, dual output air intakes and does not list single intake, single output air intakes. The air compressor in this invention is not limited to dual intake, dual output air intakes; single intake, single output air intakes are also applicable.

[0081] Although specific embodiments of the invention have been shown and described in detail to illustrate the principles of the invention, it should be understood that the invention may be practiced in other ways without departing from these principles.

Claims

1. An air compressor characterized by: The air compressor comprises: an air tank for storing compressed air; a housing; a compression unit accommodated in the housing for compressing air sucked from outside and supplying the air to the air tank; the compression unit comprises a cylinder and a piston arranged in the cylinder and in sliding fit with the cylinder; a drive unit for driving the piston, the drive unit comprising a motor and a transmission mechanism, the motor being provided with a rotating shaft, the transmission mechanism being used for converting the rotating motion of the rotating shaft into the reciprocating motion of the piston for compressing air, the motor being a two-stage induction motor, the inner diameter of the cylinder ranging from 67.7 mm to 72.7 mm, and the stroke of the piston ranging from 13 mm to 20 mm; so that the air compressor has an air filling time of not more than 70 seconds.

2. The air compressor of claim 1, wherein: The inner diameter of the cylinder ranges from 67.7 mm to 72.7 mm, and the stroke of the piston ranges from 14 mm to 20 mm; the air compressor has an air filling time of not more than 65 seconds.

3. The air compressor of claim 1, wherein: The inner diameter of the cylinder ranges from 69.7 mm to 72.7 mm, and the stroke of the piston ranges from 13 mm to 20 mm; the air compressor has an air filling time of not more than 60 seconds.

4. The air compressor of claim 1, wherein: The inner diameter of the cylinder ranges from 69.7 mm to 72.7 mm, and the stroke of the piston ranges from 14 mm to 20 mm; the air compressor has an air filling time of not more than 55 seconds.

5. The air compressor of claim 1, wherein: The piston comprises a leather cup, and the material of the leather cup is polytetrafluoroethylene.

6. The air compressor of claim 1, wherein: The material of the cylinder is aluminum plated with porcelain, steel plated with chromium, or aluminum anodized.

7. The air compressor of claim 1, wherein: One end of the cylinder is in abutment with a valve plate, and the minimum gap between the valve plate and the piston is defined as a top gap, and the range of the top gap is 0.2 mm to 0.8 mm.

8. The air compressor of claim 7, wherein: The range of the top gap is 0.4 mm to 0.6 mm.

9. The air compressor of claim 1, wherein: One end of the cylinder is in abutment with a valve plate, and the valve plate comprises a first side surface facing the piston, and a recess is arranged on the first side surface for accommodating an air inlet valve piece, the air inlet valve piece is completely accommodated in the recess, and the distance between the air inlet valve piece and the first side surface ranges from 0.5 mm to 0.7 mm.

10. The air compressor of claim 1, wherein: One end of the cylinder is in abutment with a valve plate, and the valve plate is provided with an air inlet valve piece on the side surface facing the piston, the piston comprises a leather cup, a leather cup pressing plate connecting the leather cup and the transmission mechanism, the leather cup pressing plate is provided with a recess for at least partially accommodating the air inlet valve piece, and the depth of the recess ranges from 0.5 mm to 1 mm.

11. The air compressor of claim 1, wherein: The air compressor comprises two compression units.

12. The air compressor of claim 1, wherein: The housing comprises a support portion for accommodating the compression unit, and an upper end of the support portion is provided with a cylinder cover, and the cylinder cover is provided with an air inlet and an air outlet.

13. The air compressor of claim 1, wherein: The housing comprises a support portion for accommodating the compression unit, and an upper end of the support portion is provided with a cylinder cover, and the support portion has an upper end close to the cylinder cover and an opposite lower end, and an air outlet is arranged on the upper end.

14. An air compressor characterized by: The air compressor comprises: an air tank for storing compressed air; a housing; a compression unit accommodated in the housing for compressing air sucked from outside and supplying the air to the air tank; the compression unit comprises a cylinder and a piston arranged in the cylinder and in sliding fit with the cylinder; a drive unit for driving the piston, the drive unit comprising a motor and a transmission mechanism, the motor being provided with a rotating shaft, the transmission mechanism being used for converting the rotating motion of the rotating shaft into the reciprocating motion of the piston for compressing air, the motor being a two-stage induction motor, the inner diameter of the cylinder ranging from 67.7 mm to 72.7 mm, and the stroke of the piston ranging from 13 mm to 20 mm; so that the air compressor has an air filling time of not more than 70 seconds. Driving unit for driving the piston, the driving unit includes a motor and a transmission mechanism, the motor is provided with a rotating shaft, the transmission mechanism is used for converting the rotating motion of the rotating shaft into the reciprocating motion of the piston, for compressing air, the motor is a two-stage induction motor, the inner diameter of the cylinder ranges from 65.7mm to 72.7mm, and the stroke of the piston ranges from 14mm to 20mm; so that the air compressor is not more than 70 seconds.

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