Compressor

Abstract

To improve compression efficiency in a compressor.SOLUTION: A compressor includes: a cylinder that has a cylinder body, and a cylinder plate blocking an end portion of the cylinder body; a piston that reciprocates in the cylinder; a connection rod that supports the piston; a crank shaft that applies rotation force to an end portion of the connection rod; and a crank case that rotatably supports the crank shaft. The piston is a rocking piston that reciprocates in the cylinder while rocking according to rotations of the crank shaft. At least a surface of the piston that contacts an inner circumference of the cylinder body is made of a wear-resistant resin. An outer peripheral surface of the piston becomes a spherical surface of a diameter smaller than a diameter of the cylinder body. The piston, the cylinder body, and the cylinder plate form a compression chamber. A hollow portion is formed between the piston and the connection rod, and a suction port for introducing gas into the compression chamber is disposed on the cylinder plate.SELECTED DRAWING: Figure 4C

Description

[Technical field]

[0001] The present invention relates to a compressor. [Background technology]

[0002] A reciprocating compressor is known in which a gas layer is provided between a disk portion of a piston and a retainer to prevent the compression heat generated in a compression chamber from being transferred to a connecting rod bearing (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-248812 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the reciprocating compressor of Patent Document 1, a gap is provided over the entire surface between the retainer and the disk of the piston. This gap serves as a gas passage and is further connected to the inside of the crankcase via a number of passage holes. In this way, a gas layer is formed between the retainer and the disk of the piston. This gas layer prevents the compression heat generated in the compression chamber from being transferred to the connecting rod.

[0005] In this reciprocating compressor, when a suction valve attached to the upper surface of the retainer opens, new gas that has passed through the gas layer from the space in the crankcase is sucked into the cylinder through the suction hole.

[0006] With this configuration, gas flows from the crankcase side when the piston is actuated, thereby suppressing a rise in temperature of the gas layer.

[0007] However, in the intake structure of Patent Document 1, heat dissipated from the compression chamber is transferred to the gas layer, so the temperature of the gas drawn into the cylinder increases.

[0008] Therefore, the expanded gas is drawn into the cylinder. Generally, the lower the temperature of the gas being drawn in, the higher the compression efficiency of the gas is, so further improvement in efficiency is required.

[0009] An object of the present invention is to provide a compressor having high compression efficiency. [Means for solving the problem]

[0010] The present invention includes many means for solving the above problems. One example of the present invention is a cylinder having at least a cylindrical cylinder body and a cylinder plate closing an end of the cylinder body, a piston reciprocating within the cylinder, a connecting rod supporting the piston, and a crankshaft applying a rotational force to an end of the connecting rod, the piston being an oscillating piston that reciprocates while oscillating within the cylinder as the crankshaft rotates, at least a surface of the piston that contacts an inner periphery of the cylinder body is made of a resin having wear resistance, the outer periphery of the piston is spherical, a compression chamber is formed by the piston, the cylinder body, and the cylinder plate, and the piston A metal piston insert is provided inside the piston, and the piston insert is fixed to the connecting rod by a fixing member. and the connecting rod, and an intake port for introducing gas into the compression chamber is disposed on a side surface of the cylinder plate or an end portion of the cylinder body. Effect of the Invention

[0011] According to the present invention, compression efficiency can be improved by sucking in gas from an intake port provided on the side surface of the end of the cylinder plate or the cylinder body.

[0012] Other objects, configurations and advantages than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0013] [Figure 1]FIG. 1 is a schematic diagram of a compressor according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a partial cross-sectional view of the compressor body of the first embodiment. [Figure 3A] FIG. 2 is a front view of a configuration example of a piston connecting rod in the first embodiment. [Figure 3B] FIG. 2 is a rear view of a configuration example of a piston and connecting rod in the first embodiment. [Figure 3C] 3B is a partial cross-sectional view taken along the line AA in FIG. 3A according to the first embodiment. [Figure 3D] 4 is a partial cross-sectional view taken along line BB in FIG. 3C in the first embodiment. [Figure 4A] FIG. 11 is a front view of a configuration example of a piston and connecting rod in Example 2. [Figure 4B] FIG. 11 is a rear view of an example of a configuration of a piston and connecting rod in Example 2. [Figure 4C] 4B is a partial cross-sectional view taken along the line AA in FIG. 4A according to the second embodiment. [Figure 4D] FIG. 5 is a partial cross-sectional view taken along line BB in FIG. 4C according to the second embodiment. [Figure 5A] FIG. 11 is a partial cross-sectional view of an example of a configuration of a piston and connecting rod in a third embodiment. [Figure 5B] FIG. 11 is a perspective view of a piston provided with a cooling member (cooling fins) in Example 3, as viewed from the back surface side. [Figure 5C] FIG. 11 is a perspective view of a piston provided with a cooling member (cooling pin) in Example 3, as viewed from the back surface side. [Figure 6] FIG. 2 is a partial cross-sectional view showing the flow of intake gas near the cylinder head of the first embodiment. [Figure 7A] FIG. 2 is a plan view of an example of a cylinder plate in the first embodiment. [Figure 7B] FIG. 4 is a rear view of an example of the cylinder plate in the first embodiment. [Figure 8] FIG. 11 is a partial cross-sectional view showing the flow of intake gas and discharge gas near a cylinder head in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [Example 1] A first embodiment of a compressor according to the present invention will be described with reference to Figs. 1 to 3D.

[0015] First, the overall configuration of a compressor 1 of this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram of a compressor 1 in the embodiment 1. Also, Figure 2 is a partial cross-sectional view of a compressor body 10 in this embodiment.

[0016] The compressor 1 shown in FIG. 1 includes a compressor body 10, an electric motor 2 that drives the compressor body 10, and a tank 3 for storing the gas discharged from the compressor body 10.

[0017] The compressor body 10 compresses gas such as air by a piston 33 that reciprocates in a cylinder. As shown in Fig. 2, the compressor body 10 includes a crankshaft 24, a crankcase 21 that supports the crankshaft 24 rotatably around a rotation center axis 24a, one cylinder 22 that protrudes vertically from the crankcase 21, a connecting rod 32 whose base end is rotatably connected to a crank pin of the crankshaft 24, and a piston 33 fixed to the tip end of the connecting rod 32. The cylinder 22 includes a cylindrical cylinder body 25, a cylinder plate 26 that closes an end (upper end) of the cylinder body 25, and a cylinder head 23.

[0018] The cylinder plate 26 is sandwiched between the cylinder head 23 and the cylinder body 25. The compression chamber 22X is formed by the piston 33, the cylinder inner wall surface 22a which is the inner peripheral surface of the cylinder body 25, and the cylinder plate 26. The cylinder plate 26 is provided with an intake port 26AG (see Figs. 6 and 7A) for introducing gas into the compression chamber 22X, and a discharge port 26BG (see Fig. 7B) for discharging the gas compressed in the compression chamber 22X. An intake valve 26a (see Figs. 6 and 7B) is attached to the intake port 26AG, and a discharge valve 26b (see Fig. 7A) is attached to the discharge port 26BG.

[0019] In this embodiment, the cylinder plate 26 is disposed on the side opposite to the crankshaft 24 with the piston 33 interposed therebetween.

[0020] As shown in FIG. 2, as the piston 33 reciprocates while oscillating within the cylinder 22 as the crankshaft 24 rotates, the central axis 30X of the piston - connecting rod during the reciprocating motion is generally inclined with respect to the central axis 22b of the cylinder.

[0021] In the compressor main body 10, when the crankshaft 24 is rotated by the electric motor 2, a rotational force is applied to one end of the connecting rod 32, and the piston 33 installed in the cylinder 22 reciprocates within the cylinder 22. In the intake process where the piston 33 moves from the top dead center to the bottom dead center, the compression chamber 22X expands, and the intake valve 26a provided on the cylinder plate 26 (see FIGS. 6 and 7B) opens, and gas is sucked into the compression chamber 22X from the intake chamber in the cylinder head 23 through the intake port 26AG.

[0022] FIG. 6 is a partial cross - sectional view showing the flow of the sucked gas in the vicinity of the cylinder plate 26 in this embodiment. FIG. 7A is a plan view of an example of the cylinder plate 26 in this embodiment. FIG. 7B is a rear view of an example of the cylinder plate 26 in this embodiment.

[0023] As shown in FIGS. 6, 7A, and 7B, the intake valve 26a that is disposed on the cylinder plate 26 and opens and closes the intake port 26AG, and the discharge valve 26b that opens and closes the discharge port 26BG operate in response to the reciprocating motion of the piston 33.

[0024] In the compression process where the piston 33 moves from the bottom dead center to the top dead center, the volume of the compression chamber 22X contracts, the gas in the compression chamber 22X is compressed, the discharge valve 26b provided on the cylinder plate 26 (see FIG. 7A) opens, and the compressed gas is discharged from the discharge port 26BG (see FIG. 7B) to the exhaust chamber in the cylinder head 23, and the compressed gas is sent to the tank 3 through the pipe 7 (see FIG. 1) connected to this exhaust chamber.

[0025] Note that, for the sake of simplicity in the description in FIGS. 1 and 2, the shape of the compressor is a single-cylinder single-stage compressor having only one pair of piston-cylinders. However, the compressor 1 may have a configuration in which a plurality of sets of piston-cylinders are arranged in series or radially with respect to the crankshaft.

[0026] The compressor main body 10 is arranged and fixed on the tank 3 with the crankshaft 24 arranged parallel to the rotating shaft of the electric motor 2. As shown in FIG. 1, a compressor pulley 4 is fixed to the crankshaft 24. An electric motor pulley 5 is fixed to the rotating shaft of the electric motor 2. The compressor pulley 4 attached to the compressor main body 10 has blades, and by generating wind toward the compressor main body 10 as it rotates, heat dissipation of the compressor main body 10 is promoted.

[0027] A transmission belt 6 for transmitting power is wound around the compressor pulley 4 and the electric motor pulley 5 between the compressor pulley 4 and the electric motor pulley 5. Thereby, following the rotation of the electric motor 2, the crankshaft 24 of the compressor main body 10 is rotationally driven via the electric motor pulley 5, the transmission belt 6, and the compressor pulley 4, and the compressor main body 10 compresses the gas.

[0028] Note that, for the sake of simplicity in the description in FIG. 1, the compressor main body 10 is configured to be connected via the electric motor 2 and the transmission belt 6, but the connection method is not limited to this. The crankshaft 24 of the compressor main body 10 and the rotating shaft of the electric motor 2 may be directly connected using a connection means such as a coupling.

[0029] Next, the peripheral structure of the piston will be described with reference to FIG. 2. In the compressor main body 10 shown in FIG. 2, a swinging piston method in which the piston 33 is integrally formed with the connecting rod 32 is used. In this swinging piston method, as the crankshaft 24 rotates, the piston 33 reciprocates while swinging within the cylinder 22.

[0030] Next, the piston 33 and the connecting rod 32 will be described with reference to Fig. 3A to Fig. 3D. Fig. 3A is a front view of an example of the piston-connecting rod configuration in this embodiment, Fig. 3B is a rear view, Fig. 3C is a partial cross-sectional view taken along line AA in Fig. 3A, and Fig. 3D is a partial cross-sectional view taken along line BB in Fig. 3C.

[0031] 3A and 3B is a separate part from the connecting rod 32 that supports the piston 33. At least an outer peripheral surface 33a that contacts the inner peripheral side of the cylinder body 25 and an upper surface 33c of the piston on the cylinder plate 26 side are made of a resin having wear resistance.

[0032] In this embodiment, the piston 33 is made of resin having excellent wear resistance, except for a piston insert 41 (see FIG. 3D) described later.

[0033] An example of a resin material having excellent wear resistance that can be used to form the piston 33 is polytetrafluoroethylene (PTFE). Furthermore, when the thermal expansion coefficient is taken into consideration, an example of the resin material for the piston 33 is polyphenylene sulfide (PPS).

[0034] The outer peripheral surface 33a of the piston 33 is a sphere having a diameter slightly smaller than the diameter of the inner peripheral side of the cylinder body 25. The center of the outer peripheral surface 33a having the spherical shape is the outer peripheral center 33d (see Figs. 3A and 3C). As shown in Fig. 3C, a piston protrusion 33e is formed on the outer peripheral portion facing the connecting rod 32 among the surface of the piston 33 on the connecting rod 32 side, and is fitted with the connecting rod protrusion 32d of the connecting rod 32. A ring groove 33b is provided on the outer periphery of the piston 33 that contacts the cylinder inner wall surface 22a, and a piston ring 34 is fitted into the ring groove 33b. The piston ring 34 is a seal ring that seals the gap between the cylinder inner wall surface 22a and the outer peripheral surface 33a of the piston 33.

[0035] Furthermore, the piston 33 is molded with a piston insert 41 made of a metal such as an aluminum alloy embedded therein. This piston insert 41 is for preventing the piston 33 from coming off the connecting rod 32 even when the piston 33 is pulled toward the cylinder head 23 by the reciprocating inertia force or frictional force and receives a load. As shown in FIG. 3D, an edge portion 41a of the piston insert 41 is shaped to bite into the piston 33 in the circumferential direction so that the piston 33 does not come off. Furthermore, the piston insert 41 is formed with at least one female screw hole 41c opening toward the crankcase 21 side (two in this embodiment) so that the piston 33 can be fixed to the connecting rod 32 with a screw. As shown in FIG. 2, the piston 33 is fastened (fixed) to the connecting rod 32 with two screws 35 located from the crankcase 21 side in a direction perpendicular to the crankshaft 24.

[0036] Correspondingly, in this embodiment, the connecting rod 32 shown in FIG. 3D has a screw through hole 32c for the screw 35 at a position on the seat surface that supports the piston 33, which position coincides with the female thread hole 41c.

[0037] As shown in Fig. 3D, the piston insert 41 of this embodiment is dish-shaped with the cylinder head 23 side at the bottom. A connecting rod recess 32b is formed in the seating surface of the connecting rod 32 at a position corresponding to the recess in the center of the dish shape of the piston insert 41, and is recessed toward the crankshaft 24 side (the lower side in the figure). With this structure, a hollow portion 41b is formed between the lower surface of the piston insert 41 and the upper surface of the connecting rod 32. In this hollow portion 41b, the upper surface of the piston 33 is covered by the piston insert 41. In this embodiment, the internal space of the hollow portion 41b is a sealed space.

[0038] In addition, when hollow portion 41b as shown in FIG. 3D is formed, the resin constituting piston 33 itself will be subjected to gas load when piston 33 reciprocates, so it is preferable to take some measures to ensure strength.

[0039] 3A to 3D, the female screw hole 41c of the piston insert 41 is provided parallel to the direction of the central axis 30X of the piston connecting rod. However, the arrangement of these parts is not limited to "parallel to the central axis 30X of the piston connecting rod." For example, the female screw hole may be arranged at an angle to the central axis 30X of the piston connecting rod.

[0040] In this embodiment, the hollow portion 41b is formed between the piston 33 and the connecting rod 32, thereby making it possible to reduce the mass of the reciprocating parts including the piston 33 and the connecting rod 32. As a result, vibration of the compressor body 10 caused by the reciprocating inertia force is suppressed.

[0041] Furthermore, the upper surface of the piston 33 in the hollow portion 41b is covered by the piston insert 41. Therefore, the piston 33 is held from the inside by the piston insert 41, so that even when the hollow portion 41b is formed, the amount of deformation due to contraction during molding of the piston 33 and expansion due to compression heat during operation is reduced.

[0042] In addition, the crankcase 21 is provided with a ventilation hole (not shown) that is open to the outside air. The internal volume of the crankcase 21 increases and decreases with the reciprocating motion of the piston 33, and air is drawn in from the outside through the ventilation hole and exhausted to the outside. In this way, ventilation through the ventilation hole achieves cooling of the inside of the crankcase 21.

[0043] In order to prevent the inhalation of dust, a breathing filter 27 (see FIG. 2) is attached to the breathing hole, which filters the outside air that flows into the space of the crankcase 21.

[0044] Furthermore, the hollow portion 41b is provided at the joint between the connecting rod 32 and the piston 33, giving the connecting rod 32 a large cross-sectional outer shape. In this embodiment, the connecting rod 32 has a generally Y-shaped cross section, and the angle of its base portion on the crankshaft side may be within a range of approximately 90° to approximately 110° with respect to the central axis 30X of the piston-connecting rod.

[0045] In this embodiment, the connecting rod recess 32b has a mortar-like or truncated cone-like shape. However, in order to fasten the piston 33 and the connecting rod 32 with the screw 35, when the internal space of the hollow portion 41b is viewed in radial cross section, the gap between the opposing inner wall surfaces in the radial direction where the screw 35 is installed, i.e., the internal dimension, is somewhat narrow.

[0046] As described above, the compressor 1 of this embodiment includes a cylinder 22 having at least a cylindrical cylinder body 25 and a cylinder plate 26 closing an end of the cylinder body 25, a piston 33 reciprocating in the cylinder 22, a connecting rod 32 supporting the piston 33, and a crankshaft 24 applying a rotational force to an end of the connecting rod 32. The piston 33 is a rocking piston that reciprocates while rocking in the cylinder 22 as the crankshaft 24 rotates. At least the surface of the piston 33 that contacts the inner periphery of the cylinder body 25 is made of a resin having wear resistance. The outer periphery 33a of the piston 33 is spherical. The piston 33, the cylinder body 25, and the cylinder plate 26 form a compression chamber 22X. A hollow portion 41b is formed between the piston 33 and the connecting rod 32, and an intake port 26AG for introducing gas into the compression chamber 22X is arranged in the cylinder plate 26.

[0047] Next, the effects of this embodiment will be described.

[0048] The piston 33 of the first embodiment of the present invention described above is an oscillating piston that reciprocates while oscillating in the cylinder 22 in accordance with the rotation of the crankshaft 24. At least the outer peripheral surface 33a of the piston 33 that contacts the inner peripheral side of the cylinder body 25 is made of a resin having wear resistance. The outer peripheral surface 33a of the piston 33 is a resin spherical surface having a diameter smaller than that of the cylinder body 25. Alternatively, a part of the spherical surface having a diameter larger than that of the cylinder body 25 may be the outer peripheral surface 33a of the piston 33. The compression heat received by the piston upper surface 33c is insulated by the resin outer peripheral surface 33a provided on the piston 33.

[0049] In addition, by using resin as a constituent material of the piston 33, in a rocking piston type compressor, the gap between the outer circumferential surface 33a of the piston 33 and the cylinder inner wall surface 22a (see FIG. 2) is kept small, which provides the effect of enabling the piston 33 to slide smoothly. In addition, it is possible to prevent the piston ring 34 from being deformed or damaged, or from having poor sealing properties, due to an increase in the rocking angle.

[0050] Furthermore, in the compressor 1 of this embodiment, by providing the hollow portion 41b between the piston 33 and the connecting rod 32, it is possible to reduce the mass of the reciprocating parts including the piston 33 and the connecting rod 32. Therefore, vibration of the compressor body 10 caused by the reciprocating inertia force is suppressed.

[0051] In addition, the volumetric efficiency can be improved by sucking in unexpanded gas, such as air at room temperature, through the intake port 26AG provided in the cylinder plate 26. As a result, the compression efficiency can be increased.

[0052] In addition, since the connecting rod 32 of this embodiment is formed in a substantially Y-shape, it has higher mechanical rigidity than the conventional substantially T-shaped connecting rods, and is less susceptible to breakage of the connecting rod 32 due to the locking phenomenon of the reciprocating parts. This improves the reliability of the joint between the connecting rod 32 and the piston 33 in the compressor 1.

[0053] Therefore, the compressor 1 of this embodiment can operate more stably than the conventional compressor in which the connecting rod and the piston are connected to a solid body.

[0054] [Example 2] A second embodiment will be described with reference to Figures 4A to 4D. The same components as those in the first embodiment are given the same reference numerals, and the description thereof will be omitted. The same applies to the following embodiments.

[0055] Fig. 4A is a front view of an example of the configuration of a piston connecting rod in this embodiment, Fig. 4B is a rear view, and Fig. 4C is a partial cross-sectional view taken along line AA in Fig. 4A. Fig. 4D is a partial cross-sectional view taken along line BB in Fig. 4C. In Example 1, the internal space of hollow portion 41b is an enclosed space.

[0056] In contrast to this, in this embodiment 2, as shown in Figures 4A, 4B, and 4C, in comparison to embodiment 1, two communication holes 32e, 32f that communicate between the space of the crankcase 21 and the hollow portion 41b are provided on the upper end face side of the connecting rod 32 that contacts the hollow portion 41b.

[0057] Next, the position and shape of the openings of the communication holes 32e and 32f will be described. As shown in Fig. 4B, the opening of the communication hole 32e in this embodiment is generally fan-shaped, and its center point is located near the base 32Y of the connecting rod 32 which is generally Y-shaped.

[0058] The arc portion of the approximately sector shape of communication hole 32e faces piston 33. As shown in Fig. 4A, when piston 33 is viewed from the front, the opening of communication hole 32f has an approximately semicircular or partial circle shape.

[0059] The volume of the hollow portion 41b can be set large as long as the mechanical strength of the connecting rod 32, whose joint with the piston 33 has a substantially Y-shaped cross section, is maintained and at least two screw through holes 32c can be provided. This reduces the weight of the connecting rod 32. In order to promote heat dissipation through ventilation to the hollow portion 41b, the positions of the communication holes and the opening shapes of the communication holes are appropriately adjusted in accordance with the shape and size of the connecting rod 32, and then ventilation holes 32e, 32f of required sizes are provided on the upper surface side of the connecting rod 32.

[0060] Therefore, in addition to the above, several other configuration examples in which the number of communication holes, the opening shape, and the opening direction are changed are possible.

[0061] For example, the cross-sectional shape of the communication hole 32e may be circular or elliptical. In addition, the communication hole 32e is preferably disposed so as to face the communication hole 32f across the central axis 30X of the piston-connecting rod in a radial cross section of the piston 33.

[0062] The cross-sectional shape of the communication hole 32f, which serves as an extrusion port for gas when the piston 33 descends, may be an elongated hole or an elliptical shape. A plurality of communication holes 32f may be arranged within an angular range of about 10° to 30° in the radial direction of the piston 33.

[0063] Basically, when taking into consideration the active introduction of gas from crankcase 21 into the internal space of hollow portion 41b, it is particularly preferable to provide communication holes 32e and 32f so that their opening faces face in different directions.

[0064] When multiple communication holes are provided, it is preferable that at least one of them opens on the crankshaft 24 side, like communication hole 32e. Also, it is preferable that at least one of them opens in the radial direction of the cylinder body 25, like communication hole 32f. Also, when multiple communication holes are provided, it is particularly preferable that at least one of them opens on the crankshaft 24 side and at least one of them opens in the radial direction of the cylinder body 25.

[0065] Also, in the same manner as in the first embodiment, in the present embodiment, the crankcase 21 is provided with a breathing hole (not shown) that is open to the outside air, and a breathing filter 27 for preventing the intake of dust is attached to the breathing hole.

[0066] 4C, the communication hole 32e serves as an intake port through which gas within the crankcase 21 is taken into the hollow portion 41b when the piston 33 descends. In contrast, the communication hole 32f serves as an extrusion port through which gas within the hollow portion 41b is extruded to the outside when the piston 33 descends.

[0067] Therefore, the communication holes 32e and 32f open in different directions from the inner hollow portion 41b toward the outside. When the piston 33 descends, the opening of the communication hole 32e, which serves as the gas intake port, faces from the hollow portion 41b toward the crankshaft 24. In contrast, the opening of the communication hole 32f, which serves as the gas extrusion port, faces radially outward of the cylinder body 25.

[0068] Also, when the piston 33 moves upward, a certain amount of gas flow can occur between the hollow portion 41b and the space outside the connecting rod 32.

[0069] Next, the effects of this embodiment will be described.

[0070] In the piston 33 of this embodiment, similarly to the first embodiment, the outer peripheral surface 33a of the piston 33 that contacts the inner peripheral side of the cylinder body 25 is made of abrasion-resistant resin and is a resin spherical surface with a diameter smaller than the diameter of the cylinder body 25. As a result, the compression heat received by the piston upper surface 33c is insulated by the piston 33.

[0071] Furthermore, in the compressor 1 of this embodiment, the space of the hollow portion 41b and the space of the crankcase 21 are communicated with each other through the communication holes 32f and 32e.

[0072] Therefore, the hollow portion 41b is cooled by the gaseous cooling air 42 (see FIG. 4C).

[0073] Due to the enhanced cooling effect achieved by these configurations, the compressor 1 of this embodiment can prevent deformation of the piston ring 34 more effectively than the compressor of the prior art in which the connecting rod and piston are connected with a solid core, and the excellent sliding properties of the spherical resin outer circumferential surface 33a improve sealing performance. In addition, since the temperature rise of the intake gas can be prevented, the volumetric efficiency is improved and more stable operation can be achieved. Furthermore, the compression efficiency can be improved. In addition, by cooling the piston 33, heat transfer to the connecting rod 32 is less likely to occur, so the life of the bearing of the connecting rod 32 is extended.

[0074] [Example 3] Example 3 will be described with reference to Figures 5A to 5C. In this example, in comparison with Example 2, a cooling member for promoting heat dissipation is further provided on the piston insert back surface 41d so as to enhance the cooling effect in the hollow portion 41b and further promote heat dissipation of the piston 33.

[0075] Fig. 5A is a partial cross-sectional view of an example of the configuration of a piston connecting rod in this embodiment, taken along the line AA in the front view shown in Fig. 4A. A cooling member (cooling pin 41f) is provided on the back surface 41d of the piston insert of the piston 33.

[0076] 5B is a perspective view of the piston 33 including the piston insert back surface 41d provided with the cooling fins 41e used as a cooling member, as viewed from the back surface side. In this embodiment, the cooling fins 41e are preferably arranged so that their arrangement direction is aligned with the flow of the cooling air 42 in the internal space of the hollow portion 41b.

[0077] 5C is a perspective view of the piston 33 including the piston insert back surface 41d provided with the cooling pins 41f used as cooling members, as viewed from the back surface side. The piston insert 41 is provided with a number of cooling pins 41f protruding from the piston insert back surface 41d as cooling members. In this embodiment, the number of cooling pins 41f are arranged in a staggered pattern. When using these cooling pins 41f, a large amount of gas comes into contact with each cooling pin 41f. Therefore, the cooling efficiency is less dependent on the flow direction of the gas in the internal space of the hollow portion 41b.

[0078] In this embodiment, a breathing hole (not shown) provided in the crankcase 21 and a breathing filter 27 for filtering are attached in the same manner as in the second embodiment.

[0079] Next, the effects of this embodiment will be described.

[0080] In this embodiment as well, since the outer peripheral surface 33a of the piston 33 is made of resin, the compression heat generated inside the cylinder 22 is insulated by the piston 33. In addition, since a hollow portion 41b is formed between the piston 33 and the connecting rod 32, the mass of the reciprocating part including the piston 33 and the connecting rod 32 is reduced. As a result, it is possible to improve vibration of the compressor body 10 caused by reciprocating inertia force.

[0081] Furthermore, in this embodiment, the piston insert back surface 41d is provided with cooling fins 41e or cooling pins 41f as cooling members for promoting heat dissipation from the piston 33. These cooling members increase the amount of heat dissipated from the piston insert back surface 41d.

[0082] In the compressor 1 of this embodiment, a metal piston insert 41 having a female thread hole 41c is provided inside the piston 33, the piston insert 41 is fixed to the connecting rod 32 from the crankcase 21 side with a screw 35, and a hollow portion 41b is formed between the piston insert 41 and the connecting rod 32. Therefore, the mass of the reciprocating part including the piston 33 and the connecting rod 32 is reduced.

[0083] An intake port 26AG connected to the compression chamber 22X is provided in the cylinder plate 26, and the space of the hollow portion 41b and the space of the crankcase 21 are communicated with each other through communication holes 32f and 32e. Therefore, heat dissipation from the piston 33 is promoted.

[0084] Furthermore, the surface of the piston insert 41 facing the crankcase 21, i.e., the piston insert back surface 41d, has cooling fins 41e and cooling pins 41f as cooling members for promoting heat dissipation. Therefore, heat dissipation from the piston 33 is further promoted compared to the case where the piston insert 41 is not provided with a cooling member.

[0085] Therefore, in the compressor 1 of this embodiment, the life of the bearing of the connecting rod 32 is relatively longer than that of the second embodiment described above.

[0086] [Variations] The modified example will be described with reference to Fig. 8. In this modified example, the structure of the intake valve 26a and the intake port 26AG that supply gas into the inside of the cylinder body 25 is different from that of the first, second, and third embodiments in which the intake port 26AG is provided in the cylinder plate 26.

[0087] 8, a discharge port 26BG and a discharge valve 26b for opening and closing the discharge port 26BG are provided in the cylinder plate 26. The compressed gas discharged from the discharge port 26BG is sent to the tank 3 through the external piping 7 from the exhaust port 26BO.

[0088] Gas is supplied to the inside of cylinder body 25 through intake ports 26AG provided on the side surface at the end of cylinder body 25. In response to the reciprocating motion of piston 33, intake valves 26a operate to open and close a plurality of intake ports 26AG.

[0089] In this modified example, intake port 26AG is disposed axially below cylinder body 25's top dead center of piston 33. In other words, intake port 26AG is disposed below the top of piston 33 at top dead center, and therefore intake port 26AG is not exposed to compression chamber 22X when piston 33 is at top dead center.

[0090] Next, when the piston 33 starts to descend from the top dead center position for intake, the intake port 26AG is exposed to the cylinder inner wall surface 22a. At this stage, gas is supplied to the inside of the compression chamber 22X from the multiple intake ports 26AG facing each other on the cylinder inner wall surface 22a, and collision compression of the gas occurs. In this case, the expanded gas is not drawn in, and the volumetric efficiency of the finally compressed gas is further improved.

[0091] Thus, in this modified example, the discharge port 26BG attached to the cylinder plate 26 and the intake port 26AG provided on the side of the end of the cylinder body 25 are positioned on the opposite side of the crankshaft 24 across the piston 33.

[0092] Next, the effects of this modified example will be described.

[0093] In this modified example, the intake port 26AG is disposed axially below the top dead center of the piston 33 in the cylinder body 25. This further improves the volumetric efficiency when the external gas is taken in and compressed.

[0094] The intake / discharge mechanism of this modification can be used in combination with the piston / connecting rod configurations in the above-mentioned embodiments 1 to 3. In that case, even if the gas compression rate is set higher, the compressor 1 of this modification can maintain high volumetric efficiency by providing a hollow portion 41b in the piston / connecting rod and promoting heat dissipation from the hollow portion 41b on the back side of the piston 33. As a result, the compression efficiency is increased.

[0095] Therefore, the compressor 1 of this modification has improved sealing performance and can maintain volumetric efficiency even when the compression ratio is set high, compared to conventional compressors in which the connecting rod and piston are connected with a solid core, and can operate more stably. In addition, the piston 33 can be cooled efficiently, which extends the life of the bearing of the connecting rod 32.

[0096] [others] The compressor of the present invention can be applied to various compressors that can employ a rocking piston system among compressors that compress various gases such as air and refrigerants, and the type, model, and use of the compressor are not particularly limited. The present invention is not limited to the above-mentioned embodiment, and includes various modified examples. The above-mentioned embodiment has been described in detail to explain the present invention in an easily understandable manner, and the present invention is not necessarily limited to the one having all of the described configurations.

[0097] It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with the configuration of another embodiment. [Explanation of symbols]

[0098] 1...compressor, 2...motor, 3...tank, 4...compressor pulley, 5...motor pulley, 6...transmission belt, 10...compressor body, 21...crankcase, 22...cylinder, 22a...cylinder inner wall surface, 22b...cylinder central axis, 23...cylinder head, 24...crankshaft, 24a...rotation central axis, cylinder body...25, 26...cylinder plate, 26a...intake valve, 26AG...intake port, 26b...discharge valve, 26BG...discharge port, 27...breathing filter, 30X...piston ·Central axis of connecting rod, 32...connecting rod, 32b...connecting rod recess, 32c...thread through hole, 32d...connecting rod protrusion, 32e...communication hole, 32f...communication hole, 33...piston, 33a...outer periphery, 33b...ring groove, 33c...piston upper surface, 33d...outer periphery center, 33e...piston protrusion, 34...piston ring, 35...thread, 41...piston insert, 41a...edge, 41b...hollow portion, 41c...female thread hole, 41d...back surface of piston insert, 42...cooling air

Claims

1. A cylinder having at least a cylindrical cylinder body and a cylinder plate closing an end of the cylinder body; A piston that reciprocates within the cylinder; A connecting rod supporting the piston; a crankshaft that applies a rotational force to an end of the connecting rod; Equipped with The piston is a swing piston that reciprocates while swinging within the cylinder in accordance with rotation of the crankshaft, At least a surface of the piston that contacts an inner periphery of the cylinder body is made of a resin having wear resistance, The outer circumferential surface of the piston is spherical. a compression chamber is formed by the piston, the cylinder body, and the cylinder plate, a metal piston insert is provided inside the piston, the piston insert is fixed to the connecting rod by a fixing member, and a hollow portion is formed between the piston insert and the connecting rod; A compressor in which an intake port for introducing gas into the compression chamber is disposed on a side surface of the end of the cylinder plate or the cylinder body.

2. 2. The compressor according to claim 1, A crankcase is provided to rotatably support the crankshaft, A compressor in which the space of the hollow portion and the space of the crankcase are communicated with each other through a communication hole.

3. 3. The compressor according to claim 2, The piston insert has a female threaded hole, The piston insert is fixed to the connecting rod from the crankcase side by a screw serving as the fixing member.

4. The compressor according to claim 3, A compressor having a cooling member for promoting heat dissipation on a surface of the piston insert facing the crankcase.

5. The compressor according to claim 4, The compressor, wherein the cooling member is a cooling fin or a cooling pin.

6. 3. The compressor according to claim 2, The compressor has two or more communication holes.

7. 7. The compressor according to claim 6, At least one of the communication holes is open to the crankshaft side.

8. 7. The compressor according to claim 6, At least one of the communication holes is open in a radial direction of the cylinder body.

9. 7. The compressor according to claim 6, At least one of the communication holes opens to the crankshaft side, and at least one of the communication holes opens in a radial direction of the cylinder body.

10. 2. The compressor according to claim 1, The compressor, wherein the intake port is disposed in the cylinder plate.

11. 2. The compressor according to claim 1, A compressor in which the intake port is disposed on a side surface of an end portion of the cylinder body.

Images