AIR COMPRESSOR

Abstract

An air compressor (100, 100A, 100B) includes a cylinder (110) with a piston passage (110a) having a rear and a front end (E1, E2), a piston (120, 120') with piston and skirt sections (122, 122', 124, 124'), a piston ring (130), and a drive unit (140). The piston section (122, 122') is located in the piston passage (110a) and has an annular groove (122a). The skirt and piston sections (122, 122', 124, 124') are connected via the rear end (E1). The piston ring (130) is located on the annular groove (122a). First and second portions (132, 134) of the piston ring (130) are located on first and second side portions (1221, 1222) of the piston portion (122, 122'), respectively. The drive unit (140) is coupled to the skirt portion (124, 124') and drives the piston portion (122, 122') to reciprocate between the front and rear ends (E1, E2) via the skirt portion (124, 124').The width (W1) of the annular groove (122a) at the first side portion (1221) is greater than that (W2) at the second side portion (1222). The first portion (132) moves along a width direction of the annular groove (122a) when the piston portion (122, 122') reciprocates.

Description

[0001] The invention relates to an air compressor, in particular to a piston air compressor.

[0002] A vehicle-mounted air compressor can be used with a tire sealant bottle to repair and inflate a vehicle tire, or it can be used to inflate the vehicle tire without a tire sealant bottle. The air compressor may be a piston air compressor. When the piston portion of the piston advances or moves forward in the cylinder, the piston ring around the piston portion is in contact with the inner wall of the cylinder, and the space in the cylinder gradually decreases as the piston portion moves forward. As a result, the air in the cylinder is compressed, and the check valve at the front end of the cylinder is opened by high-pressure air, so that the high-pressure air is discharged through the check valve.As the piston portion retracts within the cylinder, the space within the cylinder gradually expands, causing the internal air pressure in the cylinder to decrease. The piston portion is tilted by the rocking or swinging motion of the piston skirt portion, creating a gap between the piston ring and the inner wall of the cylinder. As a result, the air outside the cylinder is drawn into the cylinder from the rear end of the cylinder and compressed during the next forward movement of the piston, creating a continuous cycle.

[0003] However, when the piston portion retracts into the cylinder as described above, the extent to which the piston portion tilts due to the swinging motion of the skirt portion is limited. Therefore, it is difficult to further increase the gap between the piston ring and the inner wall of the cylinder, and the air intake efficiency of the cylinder cannot be improved.

[0004] US 202010132193 A1 discloses an internal combustion engine with a piston, including a piston head with an annular belt having an ignition surface and a plurality of annular grooves for receiving piston rings. A first annular groove of the plurality of annular grooves, which is arranged directly adjacent to the firing land, has an annular groove axis that runs coaxially with a piston axis of the piston. The first annular groove has an upper groove flank and a lower groove flank that is arranged remote from the firing land relative to the upper groove flank. At least the lower groove flank of at least the first annular groove is inclined by an angle of inclination relative to an orthogonal plane relative to the piston axis, wherein the angle of inclination of at least the lower groove flank varies in the circumferential direction of the piston axis.

[0005] DE 6 910 1831 T2 discloses an engine with a piston; an upper ring and a second ring mounted on the piston; partition elements mounted on the piston and connecting the upper ring and the second ring to form a gas chamber on the side surface of the piston; and a gas passage for connecting the gas chamber to an upper surface of the piston. DE 37 06 940 C1 discloses pistons for internal combustion engines with an oil control ring arranged in an annular groove on the circumference of its crown portion. The outer edge of the annular groove on the piston skirt, which adjoins the crown portion, is chamfered to form a bevel. The width of the bevel is greater on the thrust side of the piston.

[0006] DE 24 59 610 A1 discloses an assembly comprising an inner and an outer cylindrical element, wherein the inner element can be displaced within the outer element and is provided with an annular recess, wherein a locking ring is accommodated in the recess to enable the displacement of the inner element in a first direction.

[0007] DE 691 05 107 T2 discloses a device including a tilting piston with a piston head. The piston head is reciprocatingly disposed within a cylindrical bore formed in a housing, the bore being aligned along an axis. A seal is circumferentially mounted around the piston head. The seal has an outer diameter that is larger than an inner diameter of the cylindrical bore. The seal extends radially in a first direction with an axial component. A carrier is mounted circumferentially of the piston head adjacent to the seal.

[0008] DE 696 11 577 T2 discloses a piston that reciprocates in a cylinder bore of an engine and is supplied with lubricating oil. The piston includes pin bosses provided below a piston head, a symmetrical pair of skirts, and side walls connecting the pin bosses and the skirts. The side walls have openings connecting the outer side of the walls with the inner side of the walls below the central portion of the head. A recess is provided in the underside of the head to accommodate a splash of lubricating oil. The width of the recess is greater than the width of each skirt at its lower part.

[0009] The invention provides an air compressor with good air intake efficiency.

[0010] An air compressor of the invention includes a cylinder, a piston, a piston ring, and a drive unit. The cylinder has a piston passage. The piston passage has a rear end and a front end that are opposite to each other. The piston includes a piston portion and a shaft portion. The piston portion is located in the piston passage and has an annular groove, and the shaft portion is connected to the piston portion via the rear end. The piston ring is arranged on the annular groove. A first portion of the piston ring is located on a first side portion of the piston portion, and a second portion of the piston ring is located on a second side portion of the piston portion. The drive unit is coupled to the shaft portion and adapted to drive the piston portion to reciprocate between the front end and the rear end via the shaft portion.A width of the annular groove at the first side portion is larger than a width of the annular groove at the second side portion, so that the first portion of the piston ring is movable along the width direction of the annular groove when the piston portion reciprocates.

[0011] According to the invention, when the piston portion moves in a direction from the front end to the rear end, a gap between the first portion of the piston ring and an inner wall of the piston passage is increased as the first portion moves along the width direction of the annular groove.

[0012] In one embodiment of the invention, the shaft portion has an eccentric shaft portion and is coupled to the drive unit via the eccentric shaft portion. Viewed in an axial direction of the eccentric shaft portion, the first side portion and the second side portion are two radially opposite side portions of the piston portion. In one embodiment of the invention, when the piston portion moves along a direction from the front end to the rear end, the eccentric shaft portion and the first side portion are located on the same side of a central axis of the piston passage.

[0013] In one embodiment of the invention, the annular groove has a first inner wall and a second inner wall, wherein the first inner wall and the second inner wall are opposite to each other in the width direction of the annular groove, the first inner wall is located between the second inner wall and the front end, and a gap between the first portion of the piston ring and an inner wall of the piston passage is increased when the first portion moves from the second inner wall to the first inner wall.

[0014] In one embodiment of the invention, the width of the annular groove gradually increases from the second side portion to the first side portion.

[0015] In one embodiment of the invention, the piston portion has an upper surface, the upper surface faces the front end, the annular groove has a first inner wall and a second inner wall, the first inner wall and the second inner wall are opposite to each other in the width direction of the annular groove, the first inner wall is located between the second inner wall and the front end, and the first inner wall is inclined to the upper surface.

[0016] In one embodiment of the invention, the second portion of the piston ring is fixed to the annular groove.

[0017] In one embodiment of the invention, the first portion of the piston ring is adapted to move along the width direction of the annular groove by a frictional force between an inner wall of the piston passage and the first portion.

[0018] In one embodiment of the invention, the first portion of the piston ring is adapted to move along the width direction of the annular groove by a pressure difference between the rear end and the front end.

[0019] In one embodiment of the invention, the piston passage has a slope at the rear end so that an inner diameter of the piston passage at the rear end gradually increases toward an outer side of the piston passage.

[0020] In one embodiment of the invention, the piston portion and the shaft portion are pivotally connected to one another.

[0021] Based on the above, in the air compressor according to the invention, the annular groove of the piston portion is designed to have unequal widths on two sides. Accordingly, the piston ring has a movement space where the annular groove has a larger width. When the piston portion retracts, the gap between the piston ring and the inner wall of the piston passage can be increased by the movement of the piston ring, thereby improving the air intake efficiency of the cylinder. Fig. 1A and Fig. 1B each show different operating states of an air compressor of an embodiment of the invention. Fig. 2A and Fig. 2B are cross-sectional views of the air compressor of Fig. 1A or Fig. 1B. Fig. 3 is an enlarged partial view of the air compressor of Fig. 2B. Fig. 4A to Fig. 4D are cross-sectional views of an air compressor in various operating states of another embodiment of the invention. Fig. 5 is a cross-sectional view of an air compressor of another embodiment of the invention.

[0022] Fig. 1A and Fig. 1B each show different operating states of an air compressor of an embodiment of the invention. Fig. 2A and Fig. 2B are cross-sectional views of the air compressor of Fig. 1A or Fig. 1B. It is Fig. 1A to Fig. 2B. An air compressor 100 of the present embodiment is, for example, a vehicle-mounted air compressor for providing high-pressure air required for inflating and / or repairing a vehicle tire. However, the invention is not limited thereto. The air compressor 100 includes a cylinder 110, a piston 120, a piston ring 130, and a drive unit 140. The cylinder 110 has a piston passage 110a, and the piston passage 110a has a rear end E1 and a front end E2 that are opposite to each other. The piston 120 includes a piston portion 122 and a shaft portion 124. The piston portion 122 is located in the piston passage 110a and has an annular groove 122a. The annular groove 122a surrounds a central axis A1 of the piston portion 122. The shaft portion 124 is connected to the piston portion 122 via the rear end E1 of the piston passage 110a.The piston ring 130 is made of, for example, rubber or other elastic sealing materials and is arranged in the annular groove 122a of the piston portion 122 and surrounds the central axis A1 of the piston portion 122.

[0023] The drive unit 140 is, for example, a motor coupled to the shaft portion 124 of the piston 120. Specifically, the air compressor 100 further includes a gear set 150. The gear set 150 is disposed on an extended housing 1101 of the cylinder 110 and includes a first gear 152 and a second gear 154. The first gear 152 is disposed coaxially with the drive unit 140 and meshes with the second gear 154, and an eccentric shaft portion 1241 (e.g., an axle hole) of the shaft portion 124 is eccentrically connected to the center of the second gear 154 and pivotally connected to a column 1541 on the second gear 154 to achieve coupling between the drive unit 140 and the shaft portion 124.Accordingly, the drive unit 140 can drive the eccentric shaft portion 1241 of the shaft portion 124 to move about the center of the second gear 154 via the gear set 150 to drive the piston portion 122 to reciprocate between the front end E2 and the rear end E1 of the piston passage 110a via the shaft portion 124.

[0024] In the present embodiment, the second gear 154 is driven via the drive unit 140 to move along a Fig. 2A and Fig. 2B. As a result, the piston portion 122 of the piston 120 moves in the direction shown in Fig. 2A, in the piston passage 110a of the cylinder 110, the piston ring 130 around the piston portion 122 is in contact with the inner wall of the piston passage 110a, and the space in the piston passage 110a gradually decreases as the piston portion 122 advances, so that the air in the piston passage 110a is compressed. When the air pressure in the piston passage 110a is sufficiently increased as the piston portion 122 advances, the high-pressure air resists the elastic force of a check spring 1102 to push the check valve 1103 at the front end of the cylinder 110 open along the direction D1, so that the high-pressure air is discharged via the check valve 1103.

[0025] On the other hand, in the Fig. 2B, the piston portion 122 of the piston 120 in the piston passage 110a of the cylinder 110 returns along a direction D2 toward the rear end E1 of the piston passage 110a. The space in the piston passage 110a gradually increases, so that the internal air pressure thereof drops below one atmosphere (that is, lower than the external air pressure), and the piston portion 122 is tilted by the swing of the shaft portion 124 of the piston 120 to create a gap between the piston ring 130 and the inner wall of the piston passage 110a. Therefore, air F outside the cylinder 110 is sucked into the piston passage 110a from the rear end E1 of the piston passage 110a and is compressed upon the next advance of the piston portion 122, thereby forming a continuous cycle.

[0026] Fig. 3 is an enlarged partial view of the air compressor of Fig. 2B. As in Fig. 3, the piston portion 122 has a first side portion 1221 and a second side portion 1222. Along the axial direction of the eccentric shaft portion 1241 (in Fig. 2B), the first side portion 1221 and the second side portion 1222 are two radially opposite side portions of the Fig. 3. A first portion 132 of the piston ring 130 is located on the first side portion 1221 of the piston portion 122, and a second portion 134 of the piston ring 130 is located on the second side portion 1222 of the piston portion 122. A width W1 of the annular groove 122a on the first side portion 1221 is greater than a width W2 of the annular groove 122a on the second side portion 1222, so that the first portion 132 of the piston ring 130 is movable along the width direction of the annular groove 122a when the piston portion 122 reciprocates. The second portion 134 of the piston ring 130 is fixed, for example, to the annular groove 122a.

[0027] As described above, in the air compressor 100 of the present embodiment, the annular groove 122a of the piston portion 122 is designed to have unequal widths on two sides. Accordingly, the piston ring 130 has a movement space in which the annular groove 122a has a larger width. When the piston portion 122 retracts, a gap G between the piston ring 130 and the inner wall of the piston passage 110a can be increased by the movement of the piston ring 130, thereby improving the air intake efficiency of the cylinder 110.

[0028] The structure and operation of the air compressor 100 of the present embodiment will be described in more detail below.

[0029] See Fig. 3. Specifically, the annular groove 122a of the present embodiment has a first inner wall S1 and a second inner wall S2, wherein the first inner wall S1 and the second inner wall S2 are opposed to each other in the width direction of the annular groove 122a, and the first inner wall S1 is located between the second inner wall S2 and the front end E2 (in Fig. 2B) of the piston passage 110a, and the first portion 132 of the piston ring 130 can move between the first inner wall S1 and the second inner wall S2. Furthermore, the piston portion 122 has an upper surface 122b, the upper surface 122b facing the front end E2 of the piston passage 110a, and the central axis A1 of the piston portion 122 is perpendicular to the upper surface 122b. The second inner wall S2 of the annular groove 122a is parallel to the upper surface 122b, and the first inner wall S1 of the annular groove 122a is inclined toward the upper surface 122b, so that the width of the annular groove 122a gradually increases from the second side portion 1222 to the first side portion 1221, so that the annular groove 122a has a larger width W1 at the first side portion 1221, as mentioned above.

[0030] When the piston portion moves along the direction D2 from the front end E2 to the rear end E1 of the piston passage 110a, the eccentric shaft portion 1241 of the shaft portion 124 and the first side portion 1221 of the piston portion 122 are on the same side of a central axis A2 of the piston passage 110a, so that the piston portion 122 enters an inclined state as shown in Fig. 2B and Fig. 3. Consequently, when the piston portion 122 moves along the direction D2, the gap G between the first portion 132 of the piston ring 130 and the inner wall of the piston passage 110a increases as the first portion 132 moves along the width direction of the annular groove 122a from the second inner wall S2 to the first inner wall S1.

[0031] In the present embodiment, the first portion 132 of the piston ring 130 can be driven by the air flow and / or by the frictional force between the inner wall of the piston passage 110a and the first portion 132 to move from the second inner wall S2 toward the first inner wall S1, as mentioned above. In particular, when the piston portion 122 moves along the direction D2, the pressure difference between the rear end E1 and the front end E2 of the piston passage 110a causes the air F to flow along the direction from the rear end E1 to the front end E2. Therefore, the first portion 132 of the piston ring 130 can be driven by the air flow and move toward the first inner wall S1 of the annular groove 122a along the width direction of the annular groove 122a. In addition, during the process of operating the piston 120 from the state of Fig. 2A in the state of Fig. 2B, when the first portion 132 of the piston ring 130 is still in contact with the inner wall of the piston passage 110a and the piston portion 122 starts to move along the direction D2, the frictional force between the inner wall of the piston passage 110a and the first portion 132 drives the first portion 132 to move toward the first inner wall S1 of the annular groove 122a along the width direction of the annular groove 122a.

[0032] Fig. 4A to Fig. 4D are cross-sectional views of an air compressor in various operating states of another embodiment of the invention. An air compressor 100A of Fig. 4A to Fig. 4D differs from the air compressor 100 of the previous embodiment in that: the piston passage 110a of the air compressor 100A has a slope T at the rear end E1, so that the inner diameter of the piston passage 110a at the rear end E1 gradually increases toward the outside of the piston passage 110a. When the piston 120 moves along the direction D2 in the direction shown in Fig. 4C, there is a gap between the slope T of the rear end E1 and the piston ring 130 of the piston passage 110a to further improve the air intake performance of the cylinder 110. Furthermore, the check valve 1103 at the front end of the cylinder 110 may be poorly sealed, causing high-pressure air from the pneumatic device to enter the cylinder 110 via the check valve 1103 and generate high pressure. The gap between the slope T of the rear end E1 of the piston passage 110a and the piston ring 130 may further discharge the high-pressure air from the cylinder 110, as shown in Fig. 4D. This can prevent the piston 120, the drive unit 140, the gear set 150, etc., from being damaged by the impact of the high-pressure air in the cylinder 110 when the piston 120 moves along the direction D1 next time. The remaining configurations and functions of the air compressor 100A of Fig. 4A to Fig. 4D are the same as or similar to those of the air compressor 100 in the previous embodiment and will not be described again here.

[0033] Fig. Figure 5 is a cross-sectional view of an air compressor of another embodiment of the invention. The difference between an air compressor 100B of Fig. 5 and the air compressor 100A of the previous embodiment is that: a piston portion 122' and a shaft portion 124' of a piston 120' of the air compressor 100B are pivotally connected to each other along a rotation axis A3 and can be rotated relatively during the actuation process. The other configurations and functions of the air compressor 100B of Fig. 5 are the same as or similar to those of the air compressor 100A in the previous embodiment and will not be described again here.

[0034] Based on the above, in the air compressor according to the present invention, the annular groove of the piston portion is designed to have unequal widths on two sides. Accordingly, the piston ring has a movement space in which the annular groove has a larger width. When the piston portion retracts, the gap between the piston ring and the inner wall of the piston passage can be increased by the movement of the piston ring, thereby improving the air intake efficiency of the cylinder. In addition, the piston passage may have a slope at the rear end so that the inner diameter of the piston passage at the rear end gradually increases toward the outside of the piston passage. Accordingly, when the piston portion is actuated toward the rear end of the piston passage, a gap is formed between the slope at the rear end and the piston ring of the piston passage to further improve the air intake efficiency of the cylinder. List of reference symbols 100, 100A, 100B air compressor 110 cylinders 110a Piston passage E1 rear end E2 front end 120 pistons 120', 122 piston section 122', 124 shaft section 124', 122a annular groove 130 piston ring 132 first section 1221 first page section 134 second section 1222 second page section 140 drive unit W1, W2 width D2 direction G gap 1241 eccentric shaft section A1, A2 central axis S1 first interior wall S2 second interior wall 122b upper surface T slope

Claims

[1] Air compressor (100, 100A, 100B), comprising: a cylinder (110) having a piston passage (110a), the piston passage (110a) having a rear end (E1) and a front end (E2) opposite each other; a piston (120, 120') comprising a piston portion (122, 122') and a skirt portion (124, 124'), wherein the piston portion (122, 122') is located in the piston passage (110a) and has an annular groove (122a), and the skirt portion (124, 124') is connected to the piston portion (122, 122') via the rear end (E1); a piston ring (130) arranged on the annular groove (122a), wherein a first portion (132) of the piston ring (130) is located on a first side portion (1221) of the piston portion (122, 122') and a second portion (134) of the piston ring (130) is located on a second side portion (1222) of the piston portion (122, 122'); and a drive unit (140) coupled to the shaft portion (124, 124') and adapted to drive the piston portion (122, 122') to move back and forth over the shaft portion (124, 124') between the front end (E2) and the rear end (E1), wherein a width (W1) of the annular groove (122a) at the first side portion (1221) is greater than a width (W2) of the annular groove (122a) at the second side portion (1222), so that the first portion (132) of the piston ring (130) is movable along a width direction of the annular groove (122a) when the piston portion (122, 122') reciprocates, wherein, when the piston portion (122, 122') moves along a direction (D2) from the front end (E2) to the rear end (E1), a gap (G) between the first portion (132) of the piston ring (130) and an inner wall of the piston passage (110a) is increased as the first portion (132) moves along the width direction of the annular groove (122a). [2] The air compressor (100, 100A, 100B) according to claim 1, wherein the shaft portion (124, 124') has an eccentric shaft portion (1241) and is coupled to the drive unit (140) via the eccentric shaft portion (1241), and when viewed along an axial direction of the eccentric shaft portion (1241), the first side portion (1221) and the second side portion (1222) are two radially opposite side portions of the piston portion (122, 122'). [3] The air compressor (100, 100A, 100B) according to claim 2, wherein, when the piston portion (122, 122') moves along a direction (D2) from the front end (E2) to the rear end (E1), the eccentric shaft portion (1241) and the first side portion (1221) are located on the same side of a central axis (A1, A2) of the piston passage (110a). [4] The air compressor (100, 100A, 100B) according to claim 1, wherein the annular groove (122a) has a first inner wall (S1) and a second inner wall (S2), the first inner wall (S1) and the second inner wall (S2) being opposite to each other in the width direction of the annular groove (122a), the first inner wall (S1) being located between the second inner wall (S2) and the front end (E2), and a gap (G) between the first portion (132) of the piston ring (130) and an inner wall of the piston passage (110a) being increased as the first portion (132) moves from the second inner wall (S2) to the first inner wall (S1). [5] The air compressor (100, 100A, 100B) according to claim 1, wherein a width (W1, W2) of the annular groove (122a) gradually increases from the second side portion (1222) to the first side portion (1221). [6] The air compressor (100, 100A, 100B) according to claim 1, wherein the piston portion (122, 122') has an upper surface (122b), the upper surface (122b) faces the front end (E2), the annular groove (122a) has a first inner wall (S1) and a second inner wall (S2), the first inner wall (S1) and the second inner wall (S2) are opposite to each other in the width direction of the annular groove (122a), the first inner wall (S1) is located between the second inner wall (S2) and the front end (E2), and the first inner wall (S1) is inclined to the upper surface (122b). [7] The air compressor (100, 100A, 100B) according to claim 1, wherein the second portion (134) of the piston ring (130) is fixed to the annular groove (122a). [8] The air compressor (100, 100A, 100B) according to claim 1, wherein the first portion (132) of the piston ring (130) is adapted to move along the width direction of the annular groove (122a) via a frictional force between an inner wall of the piston passage (110a) and the first portion (132). [9] The air compressor (100, 100A, 100B) according to claim 1, wherein the first portion (132) of the piston ring (130) is adapted to move along the width direction of the annular groove (122a) via a pressure difference between the rear end (E1) and the front end (E2). [10] The air compressor (100, 100A, 100B) according to claim 1, wherein the piston passage (110a) at the rear end (E1) has a slope (T) such that an inner diameter of the piston passage (110a) at the rear end (E1) gradually increases toward an outside of the piston passage (110a). [11] The air compressor (100, 100A, 100B) according to claim 1, wherein the piston portion (122, 122') and the shaft portion (124, 124') are pivotally connected to each other.

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