JP2008075474A - Reciprocating compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small size reciprocating compressor of a simple structure capable of providing high compression efficiency. <P>SOLUTION: One end of a connecting rod 3 is connected to a rotary plate 1a attached to a rotary shaft 1 via a crank pin 2. A cylindrical piston 5 is provided in a cylindrical cylinder 6. A piston pin 4 is attached on another end of the connecting rod 3. The piston 5 is attached to the piston pin 4. The piston 5 connected to the connecting rod via the piston pin 4 reciprocates in the cylinder 6 when the rotary plate 1a is rotated, with such a structure. A part of the rotary shaft 1, the rotary plate 1a, the crank pin 2, and a part of the connecting rod 3 are provided in a crank case assembly 7a. A space in the crank case assembly 7a forms a primary compression chamber 7. A space above the piston 5 (top dead center side of the piston 5) in the cylinder 6 forms a secondary compression chamber 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reciprocating compressor that compresses a gas.

  Conventionally, a basic structure of a two-stage compression type reciprocating compressor (reciprocating compressor) has been proposed (see, for example, Patent Document 1).

  The reciprocating compressor described in Patent Document 1 includes a first-stage low-pressure side compression mechanism section and a second-stage high-pressure side compression mechanism section. Each of the low-pressure side compression mechanism and the high-pressure side compression mechanism has a cylinder, a piston, a suction valve, a discharge valve, a suction chamber, and a discharge chamber. By adopting such a two-stage compression configuration, high gas compression efficiency can be obtained.

  Here, generally, the ratio between the work amount actually required for compressing the gas and the theoretically obtained work amount is called compression efficiency. This compression efficiency decreases as the compression ratio increases.

Therefore, in the reciprocating compressor, when the final discharge pressure is set to about 1 Mpa in order to improve the compression efficiency, it is usually necessary to adopt a two-stage compression type configuration. The compression ratio refers to the ratio of the volume of air in the cylinder when the piston is at bottom dead center to the volume of air in the cylinder when the piston is at top dead center.
JP 2003-148330 A

  However, in the conventional two-stage compression type reciprocating compressor, each of the components as described above is required in each of the low pressure side compression mechanism portion and the high pressure side compression mechanism portion. As a result, the structure is complicated, the weight is large, and the cost is high.

  Further, when it is desired to realize a small and low-cost reciprocating compressor, a one-stage compression reciprocating compressor must be employed. In that case, high compression efficiency cannot be obtained.

  An object of the present invention is to provide a reciprocating compressor capable of obtaining high compression efficiency with a small and simple configuration.

  (1) A reciprocating compressor according to the present invention is a reciprocating compressor that compresses fuel gas by a driving force from a prime mover, and includes a cylinder, a primary compression chamber provided at one end of the cylinder, and other cylinders. A secondary compression chamber provided on the end side, an introduction means for introducing the fuel gas into the primary compression chamber, a discharge means for discharging the fuel gas from the secondary compression chamber, and a primary by reciprocating in the cylinder A piston that compresses the fuel gas in the compression chamber and the fuel gas in the secondary compression chamber, a conversion mechanism that is provided in the primary compression chamber and converts the driving force into the reciprocating motion of the piston, and the fuel compressed in the primary compression chamber Supply means for supplying gas into the secondary compression chamber.

  In the reciprocating compressor according to the present invention, the primary compression chamber is provided on one end side of the cylinder, and the secondary compression chamber is provided on the other end side of the cylinder. Fuel gas is introduced into the primary compression chamber by the introducing means, and fuel gas is discharged from the secondary compression chamber by the discharging means.

  The piston reciprocates in the cylinder by the conversion of the driving force by the conversion mechanism provided in the primary compression chamber. Thereby, the fuel gas in the primary compression chamber and the fuel gas in the secondary compression chamber are compressed. The fuel gas compressed in the primary compression chamber is supplied into the secondary compression chamber by the supply means.

  Thus, since the fuel gas in the primary compression chamber and the fuel gas in the secondary compression chamber are compressed by the common cylinder and the common piston, both the primary compression chamber and the secondary compression chamber are reduced in size, and the reciprocating process is performed. The configuration of the compressor can be simplified. Further, by providing the conversion mechanism in the primary compression chamber, the reciprocating compressor can be further downsized, and the configuration of the reciprocating compressor can be remarkably simplified. Further, since the configuration of the reciprocating compressor is simplified, the weight of the reciprocating compressor can be reduced, and the cost of the reciprocating compressor can be reduced.

  As described above, it is possible to compress the fuel gas in two stages in the reciprocating compressor while simplifying the configuration of the reciprocating compressor and realizing cost reduction. Thereby, high compression efficiency of fuel gas can be obtained.

  (2) The supply means may be provided on the piston. Thus, by providing the supply means on the piston, the reciprocating compressor can be further miniaturized, the configuration of the reciprocating compressor can be further simplified, and the number of parts can be reduced.

  (3) The supply means may include a gas flow path that allows the primary compression chamber and the secondary compression chamber to communicate with each other, and a valve device that causes the gas flow path to be in a communication state and a shut-off state.

  In this case, the primary compression chamber and the secondary compression chamber communicate with each other through the gas flow path. Further, the gas flow path is brought into a communication state and a cutoff state by the valve device. With such a configuration, the primary compression chamber and the secondary compression chamber can be brought into a communication state and a blocking state with a simple configuration.

  (4) The valve device may include a valve plate having a hole and a valve body that opens and closes the hole based on a difference between the pressure in the primary compression chamber and the pressure in the secondary compression chamber.

  In this case, the valve body opens and closes the hole of the valve plate based on the difference between the pressure in the primary compression chamber and the pressure in the secondary compression chamber, whereby the fuel gas in the primary compression chamber is reduced to 2 It can be easily supplied into the next compression chamber. As a result, it is possible to easily perform the two-stage compression of the fuel gas.

  (5) The primary compression chamber has an inlet for fuel gas, the secondary compression chamber has an outlet for fuel gas, and the introducing means includes a first valve provided at the inlet to be openable and closable, The discharge means includes a second valve provided at the outlet so as to be openable and closable, and the first valve and the second valve according to the pressure change in the primary compression chamber and the pressure change in the secondary compression chamber due to the reciprocating motion of the piston. The valve may be opened and closed.

  In this case, the fuel gas is supplied from the inlet through the first valve into the primary compression chamber, and discharged from the outlet through the second valve to the outside. Further, the first compression of the fuel gas is performed by opening and closing the first valve and the second valve according to the pressure change in the primary compression chamber and the pressure change in the secondary compression chamber due to the reciprocating motion of the piston. The fuel gas compressed in two stages can be easily discharged from the secondary compression chamber to the outside while being easily supplied into the chamber.

  (6) The reciprocating compressor may further include a cylinder head that is attached to one end of the cylinder and forms a secondary compression chamber together with the cylinder, and the discharge means may be provided in the cylinder head.

  In this case, by forming the secondary compression chamber in the cylinder head and providing the discharge means in the cylinder head, a space for providing the secondary compression chamber and the discharge means becomes unnecessary. Thereby, the reciprocating compressor can be further reduced in size and the number of parts can be reduced.

  (7) The volume of the secondary compression chamber is preferably smaller than the volume of the primary compression chamber. Thus, the fuel gas compressed in the primary compression chamber can be further compressed in the secondary compression chamber, and a fuel gas with high compression efficiency can be obtained.

  (8) The conversion mechanism may include a crank mechanism, and the primary compression chamber may include a crankcase. In this case, by providing the crank mechanism in the primary compression chamber composed of the crankcase, it is not necessary to provide the primary compression chamber separately from the crankcase. As a result, the reciprocating compressor can be sufficiently miniaturized and the configuration of the reciprocating compressor can be remarkably simplified. Further, since the configuration of the reciprocating compressor is simplified, the weight of the reciprocating compressor can be reduced, and the cost of the reciprocating compressor can be reduced.

  (9) The conversion mechanism includes a rotating member that rotates by a driving force from the prime mover, and a connecting member that has one end connected to the rotating member and the other end connected to the piston, and one end of the connecting member is made of resin. The first support member may be connected to the rotation member.

  In this case, when the rotating member is rotated by the driving force from the prime mover, the piston reciprocates in the cylinder via the connecting member. Here, the oil-free property can be realized by connecting one end of the connecting member to the rotating member via the first support member made of resin. Thereby, it can prevent that oil mixes with fuel gas.

  When one end of the connecting member is fitted to the rotating member via a support member (bearing) made of metal, the connecting member becomes large corresponding to the normal size of the support member. In a normal reciprocating compressor, the size (volume) of the primary compression chamber is designed according to the size of the connecting member and the region where the rotation operation is performed. The volume must be large.

  On the other hand, in the reciprocating compressor according to the present invention, by employing the first support member made of resin, the connecting member can be designed to be small, and the volume of the primary compression chamber can be reduced.

  (10) The conversion mechanism may include a piston pin held by the piston, and the other end of the coupling member may be connected to the piston pin via a second support member made of resin.

  In this case, the other end of the connecting member is connected to the piston pin via the second support member made of resin, so that the oil-free property can be realized. Thereby, it can prevent that oil mixes with fuel gas.

  (11) The reciprocating compressor may be provided so as to surround the outer peripheral surface of the piston, and may further include a sliding member made of resin. In this case, the oil-free property can be realized. Thereby, it can prevent that oil mixes with fuel gas.

  (12) The reciprocating compressor may further include an interposition member attached to the outer peripheral surface of the piston and formed in a ring shape.

  In this case, it is possible to prevent the fuel gas from leaking between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder by mounting the interposed member formed in a ring shape on the outer peripheral surface of the piston. Therefore, the airtightness between the primary compression chamber and the secondary compression chamber can be improved.

  (13) The interposition member may have a notch. In this case, even when the intervening member is worn by repeatedly sliding on the inner peripheral surface of the cylinder, an elastic force is generated in the direction in which the notch is expanded in the intervening member. It is possible to prevent a gap from occurring between the surface. Thereby, sufficient airtightness between the primary compression chamber and the secondary compression chamber can be ensured.

  (14) The interposition member may be formed by laminating two or more interposition members having notches in different portions.

  In this case, it is possible to prevent the fuel gas from leaking from the primary compression chamber to the secondary compression chamber through the notches by providing the notches of the two or more interposed members at different positions.

  According to the reciprocating compressor according to the present invention, it is possible to obtain a fuel gas with high compression efficiency with a simple structure that can be downsized.

  Hereinafter, a reciprocating compressor according to an embodiment of the present invention will be described with reference to the drawings.

(1) Overall Configuration of Reciprocating Compressor FIG. 1 is a cross-sectional view showing the overall configuration of a reciprocating compressor according to the present embodiment.

  As shown in FIG. 1, a reciprocating compressor 100 according to the present embodiment includes a rotating shaft 1. One end of the rotating shaft 1 is connected to a prime mover (not shown) that is a driving force generating means.

  At the other end of the rotating shaft 1, a rotating plate 1a is provided. The rotating plate 1a rotates as the rotating shaft 1 rotates. One end of a connecting rod 3 is connected to the rotating plate 1a via a crank pin 2. A cylindrical piston 5 is provided in the cylindrical cylinder 6. A piston pin 4 is attached to the other end of the connecting rod 3. A piston 5 is attached to the piston pin 4. With such a configuration, when the rotating plate 1 a is rotated, the piston 5 connected to the connecting rod 3 via the piston pin 4 reciprocates in the cylinder 6.

  A part of the rotating shaft 1, a rotating plate 1a, a crankpin 2, and a part of the connecting rod 3 are provided in a crankcase assembly 7a constituted by a plurality of members. A space in the crankcase assembly 7 a forms the primary compression chamber 7.

  The rotating shaft 1 is supported by bearings 10 and 10a. In order to maintain the airtightness of the primary compression chamber 7, a seal 11 is attached to the outer peripheral surface of the rotary shaft 1 between the bearings 10 and 10 a. In addition, the clip 12 is attached to the outer peripheral surface of the rotating shaft 1 outside the bearing 10a.

  The cylinder 6 is attached so as to communicate with the primary compression chamber 7. Therefore, except for the case where the piston 5 is at the bottom dead center in the cylinder 6, a part of the space in the cylinder 6 (the space below the piston 5) of the primary compression chamber 7 that compresses the fuel gas. Have the same role as the role. In the present embodiment, natural gas is used as the fuel gas.

  An intake port 8 for sucking fuel gas into the primary compression chamber 7 is provided on the side of the crankcase assembly 7a. Inside the crankcase assembly 7a, a first intake valve 9 made of a flat lead valve is attached so that the intake port 8 can be opened and closed.

  Here, in FIG. 1, the space above the piston 5 (on the top dead center side of the piston 5) in the cylinder 6 forms a secondary compression chamber 13.

  In the present embodiment, the fuel gas compressed in the primary compression chamber 7 is further compressed in the secondary compression chamber 13. Details will be described later. In FIG. 1, since the piston 5 is at the top dead center, the volume of the secondary compression chamber 13 is small.

  A second intake valve 20 is attached to the upper portion (piston head) of the piston 5 so as to be openable and closable. The structure of the second intake valve 20 and its opening / closing operation will be described later in detail with reference to the drawings.

  A cylinder head 14 is provided above the cylinder 6. Above the second intake valve 20, a discharge valve 15 comprising a flat lead valve is provided. The discharge valve 15 is made of, for example, stainless steel (SUS), carbon tool steel (for example, SK4 or SK5), or fiber reinforced plastic (FRP: Fiber Reinforced Plastics) so as not to be corroded by the fuel gas.

  A discharge chamber 16 is formed in the cylinder head 14, and the compressed fuel gas is introduced into the discharge chamber 16 by opening the discharge valve 15.

  A discharge port 29 is provided on the side of the cylinder head 14. The discharge port 29 in the cylinder head 14 is connected to a tank or the like (not shown). Thus, the fuel gas compressed in two stages by the primary compression chamber 7 and the secondary compression chamber 13 is supplied to a tank or the like (not shown) through the discharge chamber 16.

(2) Process of Reciprocating Compressor Next, the process of the reciprocating compressor 100 will be described with reference to the following drawings.

  FIG. 2 is a cross-sectional view showing the stroke of the reciprocating compressor 100.

  As shown in FIG. 2A, first, the piston 5 moves from the bottom dead center in the cylinder 6 to the top dead center. In this case, the pressure in the primary compression chamber 7 is lower than the pressure in the intake port 8. As a result, the first intake valve 9 is opened and the fuel gas is sucked into the primary compression chamber 7 (first suction stroke).

  At the same time, the primary compression described below is completed in the previous cycle, and the fuel gas sucked into the secondary compression chamber 13 is compressed again (secondary compression). At this time, the pressure in the discharge chamber 16 is determined by the pressure in the tank connected to the discharge port 29. When the pressure in the discharge chamber 16 is higher than the pressure in the secondary compression chamber 13, the discharge valve 15 is closed. When the pressure of the secondarily compressed fuel gas becomes higher than the pressure in the discharge chamber 16, the discharge valve 15 is opened, and the compressed fuel gas is discharged into the discharge chamber 16.

  As shown in FIG. 2B, when the piston 5 moves from the top dead center in the cylinder 6 to the bottom dead center, the pressure in the primary compression chamber 7 rises to increase the first intake valve 9. And the fuel gas sucked into the primary compression chamber 7 in the first suction stroke is compressed (primary compression).

  When the pressure in the secondary compression chamber 13 becomes lower than the pressure in the primary compression chamber 7, the second intake valve 20 is opened and the primary compressed fuel gas in the primary compression chamber 7 is subjected to secondary compression. Inhaled into the chamber 13 (second inhalation stroke). Thereafter, the above-described secondary compression is performed, and the cycle is repeated.

(3) Configuration in Cylinder and Cylinder Head Next, the configuration in the cylinder 6 and the configuration in the cylinder head 14 of the reciprocating compressor 100 according to the present embodiment will be described in detail.

  FIG. 3 is a perspective view showing the configuration inside the cylinder 6 and the configuration inside the cylinder head 14 of the reciprocating compressor 100. FIG. 3 shows a state in which the cylinder 6 and the cylinder head 14 are divided into two in the length direction in order to facilitate understanding of the internal configuration of the cylinder 6 and the cylinder head 14. FIG. 3 shows a state where the piston 5 is at the top dead center.

  As shown in FIG. 3, the connecting rod 3 is disposed in the cylinder 6. The connecting rod 3 includes holes 3a and 3b having different diameters at each end.

  The above-described crank pin 2 (FIG. 1) is fitted into the hole 3a of the connecting rod 3 via a bearing 21 made of a resin material (for example, polyimide). In FIG. 3, the crankpin 2 is not shown.

  Further, the above-described piston pin 4 is fitted into the hole 3b of the connecting rod 3 through a bearing 22 made of a resin material (for example, polyimide). The piston pin 4 is attached to the piston 5 as described above.

  Here, the structure of the second intake valve 20 provided on the upper portion of the piston 5 will be described with reference to the drawings.

  FIG. 4 is a perspective view showing a state in which each component constituting the second intake valve 20 is disassembled.

  As shown in FIG. 4, the second intake valve 20 includes a valve plate 23 formed in a disc shape. A passage hole 23a through which the fuel gas compressed in the primary compression chamber 7 (FIG. 1) passes is formed at the center of the valve plate 23.

  Further, the valve plate 23 is mounted on the piston 5 so as to sandwich a piston ring 24 described later. An ejection member 26 having a circular recess 25 is attached to the upper portion of the valve plate 23 with a screw or the like. In addition, in FIG. 4, the hollow part 25 is shown in the state in which the part was notched.

  A lid-shaped valve element 27 is disposed so as to cover the passage hole 23 a of the valve plate 23. The valve body 27 includes a valve body disk 27a and a valve body shaft 27b provided in a standing state at the center of the valve body disk 27a.

  A spring 28 is disposed so as to surround the valve body shaft 27 b of the valve body 27. A spring fixing portion 26 a for fixing the spring 28 is formed in the hollow portion 25 of the ejection member 26. One end of the spring 28 is fixed to the spring fixing portion 26a. With such a configuration, the other end of the spring 28 is brought into contact with the valve disc 27 a of the valve disc 27, and the valve disc 27 a is urged by the spring 28. As a result, during normal times, the passage hole 23a of the valve plate 23 is blocked by the valve body 27, so that the fuel gas compressed in the primary compression chamber 7 does not flow out of the passage hole 23a. .

  On the other hand, as described above, when the pressure in the secondary compression chamber 13 (FIG. 1) becomes lower than the pressure in the primary compression chamber 7 and reaches the set pressure, the valve element 27 urged by the spring 28 is The valve plate is raised from above. Thereby, the fuel gas compressed in the primary compression chamber 7 flows from the passage hole portion 23a to the space of the recess portion 25 of the ejection member 26.

  Here, in the present embodiment, four slits 26 b are formed on the side surface of the recess 25 of the ejection member 26 at approximately 90 ° intervals. Note that, for example, three slits 26b may be formed on the side surface of the recessed portion 25 at intervals of approximately 120 °.

  With the configuration as described above, the fuel gas that has flowed from the passage hole portion 23a into the space of the hollow portion 25 of the ejection member 26 flows into the secondary compression chamber 13 from each of the four slits 26b.

  Returning to FIG. 3, a cylinder head 14 is provided on the upper portion of the cylinder 6. A cylinder head lid 14a is attached to the upper portion of the cylinder head 14 by a plurality of bolts 14b. In FIG. 3, the lengths of the plurality of bolts 14 b are long because the cylinder 6 is fastened to the crankcase assembly 7 a of FIG. 1.

  One end of the discharge valve 15 is fixed at a predetermined position in the cylinder head 14 by a bolt 15a. The other end of the discharge valve 15 normally partitions the space of the discharge chamber 16 formed in the cylinder head 14 and the space of the secondary compression chamber 13.

  On the other hand, when the set pressure is reached by compressing the fuel gas in the secondary compression chamber 13, the other end of the discharge valve 15 is curved. Thereby, the space of the secondary compression chamber 13 and the space of the discharge chamber 16 are connected, and the fuel gas in the secondary compression chamber 13 flows into the discharge chamber 16.

  A discharge port 29 for supplying fuel gas from the discharge chamber 16 to a tank (not shown) or the like is formed on the side of the cylinder head 14. The fuel gas flowing into the discharge chamber 16 passes through the discharge port 29 and is supplied to a tank or the like (not shown).

  Here, in the present embodiment, a sliding guide 30 made of a resin material (for example, Teflon (registered trademark) resin) is provided so as to surround the outer peripheral surface of the cylindrical piston 5. Hereinafter, the sliding guide 30 and each component of FIG. 3 will be described with reference to the following exploded view.

  FIG. 5 is a perspective view showing a state in which each component shown in FIG. 3 is disassembled.

  As shown in FIG. 5, two semi-cylindrical sliding guide components 30 a and 30 b are attached to the outer peripheral surface of the piston 5 so as to surround the outer peripheral surface of the piston 5. In the present embodiment, the two sliding guide components 30a and 30b constitute the sliding guide 30, but the sliding guide 30 formed integrally by dividing the piston 5 is configured. May be used.

  Further, the piston 5 is formed with a fuel gas passage port 5a through which fuel gas from the primary compression chamber 7 passes when flowing into the second intake valve 20. With such a configuration, the fuel gas compressed in the primary compression chamber 7 passes through the fuel gas passage 5 a of the piston 5 and then flows into the secondary compression chamber 13 through the second intake valve 20. The

(4) Role of Slide Guide and Piston Ring FIG. 6A is a cross-sectional view of the piston 5 that slides in the cylinder 6 and the second intake valve 20 provided on the top of the piston 5. FIG. 6B is an enlarged view of the region A in FIG.

  As shown in FIG. 6A, the sliding guide 30 is in contact with both end faces of the piston pin 4. In this way, the piston pins 4 are prevented from coming out of the holes 3 b of the connecting rod 3 by pressing both end surfaces of the piston pins 4 with the sliding guides 30. Further, parts such as a circlip for preventing the piston pin 4 from coming off are unnecessary, and the number of parts is reduced.

  Here, the role of the piston ring 24 will be described. As shown in FIG. 6B, the piston ring 24 is pressed in the X direction (radial direction of the piston ring 24) by the gas pressure. Thereby, the fuel gas from the Y direction perpendicular to the X direction is prevented from leaking between the outer peripheral surface of the piston 5 and the inner peripheral surface of the cylinder 6. Thus, by using the piston ring 24, the airtightness between the primary compression chamber 7 and the secondary compression chamber 13 can be improved.

  FIG. 7 is a plan view showing a state in which each component of the piston ring 24 is disassembled.

  As shown in FIG. 7, the piston ring 24 includes a first ring 24a and a second ring 24b made of a resin material. The first ring 24a and the second ring 24b are provided with notches 24c and 24d, respectively.

  The second ring 24b is provided with a convex portion 24e, and the first ring 24a is formed with a concave portion 24f made of a notch corresponding to the convex portion 24e. The piston ring 24 having a double structure is configured by fitting the convex portion 24e of the first ring 24a and the concave portion 24f of the second ring 24b.

  The piston ring 24 is often worn by sliding on the inner peripheral surface of the cylinder 6. As a result, there may be a gap between the inner peripheral surface of the cylinder 6 and the outer peripheral surface of the piston ring 24. As a result, sufficient airtightness between the primary compression chamber 7 and the secondary compression chamber 13 cannot be ensured.

  In the present embodiment, even when the piston ring 24 is worn by repeated sliding on the inner peripheral surface of the cylinder 6, the first and second rings 24a and 24b are arranged in such a direction as to expand the notches 24c and 24d. The generation of the elastic force prevents a gap from being generated between the inner peripheral surface of the cylinder 6 and the outer peripheral surface of the piston ring 24. Thereby, sufficient airtightness between the primary compression chamber 7 and the secondary compression chamber 13 can be ensured.

  In this case, by providing the notch 24c of the first ring 24a and the notch 24d of the second ring 24b at different positions, the fuel gas passes from the primary compression chamber 7 to the secondary compression chamber through the notches 24c and 24d. Leaking to 13 is prevented.

(5) Effects in the present embodiment (5-1)
In the present embodiment, by using the crank chamber as the primary compression chamber 7, it is not necessary to provide a compression chamber for primarily compressing the fuel gas separately from the crank chamber. Thereby, the configuration of the reciprocating compressor 100 can be remarkably simplified. Further, since the configuration becomes simple, the weight can be reduced, and the cost of the reciprocating compressor 100 can be reduced.

  In this way, the fuel gas can be compressed in two stages in the reciprocating compressor 100 while simplifying the configuration of the reciprocating compressor 100 and realizing cost reduction. Thereby, high compression efficiency of fuel gas can be obtained.

(5-2)
In the present embodiment, the fuel gas compressed in the primary compression chamber 7 is supplied to the secondary compression chamber 13 by providing the second intake valve 20 on the upper portion (piston head) of the piston 5. A guiding passage is provided in the piston 5. Thereby, the configuration of the reciprocating compressor 100 can be further simplified, and the number of parts can be reduced.

(5-3)
In the present embodiment, since the discharge chamber 16 and the discharge valve 15 are provided in the cylinder head 14, a space for providing the discharge chamber 16 and the discharge valve 15 becomes unnecessary. Thereby, the reciprocating compressor 100 can be reduced in size and the number of parts can be reduced.

(5-4)
In the present embodiment, the oil-free property can be realized by fitting the piston pin 4 to the connecting rod 3 via the bearing 22 made of a resin material. Thereby, it is prevented that oil mixes with fuel gas.

(5-5)
Similarly, an oil-free property can be realized by forming the sliding guide 30 and the piston ring 24 from a resin material. Thereby, it is prevented that oil mixes with fuel gas.

(5-6)
Similarly, oillessness can be realized by fitting the crank pin 2 to the connecting rod 3 via a bearing 21 made of a resin material. Thereby, it is prevented that oil mixes with fuel gas.

  When the crank pin 2 is fitted to the connecting rod 3 via a metal bearing, the connecting rod 3 becomes larger corresponding to the normal size of the bearing.

  Here, since the size (volume) of the primary compression chamber 7 is designed according to the size of the connecting rod 3 and the region where the rotating operation is performed, the volume of the primary compression chamber 7 increases as the connecting rod 3 increases. I have to be.

  On the other hand, in this Embodiment, the connecting rod 3 can be designed small by using the bearing 21 which consists of resin materials, and the volume of the primary compression chamber 7 can be reduced.

(5-7)
Further, by fitting the crank pin 2 to the connecting rod 3 using the bearing 21, the volume of the primary compression chamber 7 is reduced as compared with the case where a grease-enclosed ball bearing is employed (for example, a ball bearing is used). 20% lower than the volume in the case). Therefore, it is possible to improve the compression efficiency.

(5-8)
Further, in the present embodiment, since the piston pin 4 is fixed by the sliding guide 30, the piston pin 4 is prevented from coming off from the hole 3 b of the connecting rod 3 (a retaining effect). This eliminates the need for parts such as a circlip for preventing the piston pin 4 from coming off, reduces the number of parts, and eliminates the need for forming a groove for providing a circlip or the like.

(6) Correspondence between each constituent element of claim and each element of the embodiment Hereinafter, an example of correspondence between each constituent element of the claim and each element of the embodiment will be described. It is not limited to.

  In the above embodiment, the first intake valve 9 is an example of the introduction means and the first valve, the discharge valve 15 is an example of the discharge means and the second valve, the rotary shaft 1, the rotary plate 1a, the crank The pin 2, the connecting rod 3 and the piston pin 4 are examples of the conversion mechanism, the second intake valve 20 is an example of the supply means, the passage hole portion 23a and the slit 26b are examples of the gas flow path, and the ejection member 26 The valve body 27 and the spring 28 are examples of the valve device.

  Moreover, in the said embodiment, the rotating shaft 1, the rotating plate 1a, and the crankpin 2 are examples of a rotating member, the connecting rod 3 is an example of a connection member, and the bearing 21 is an example of a 1st support member, The bearing 22 is an example of a second support member, the sliding guide 30 is an example of a sliding member, and the piston ring 24 is an example of an interposed member.

  In addition, as each component of a claim, the other various element which has the structure or function described in the claim can also be used.

(7) Other Embodiments In the above embodiment, the gas flow path for supplying the fuel gas in the primary compression chamber 7 to the secondary compression chamber 13 is provided in the piston 5, but the present invention is not limited to this. Instead of this, the gas flow path may be provided outside the cylinder 6.

  In the above embodiment, the piston ring 24 has a double structure including the first ring 24a and the second ring 24b. However, the present invention is not limited to this, and the single structure or the triple structure or more. A laminated structure may be used.

  The present invention can be used for various vehicles including engines such as a generator, a two-wheeled vehicle, a four-wheeled vehicle, and a golf car.

It is sectional drawing which shows the whole structure of the reciprocating compressor which concerns on this Embodiment. It is sectional drawing which shows the process of a reciprocating compressor. It is a perspective view which shows the structure in the cylinder of a reciprocating compressor, and the structure in a cylinder head. It is a perspective view which shows the state by which each component which comprises a 2nd intake valve was decomposed | disassembled. FIG. 4 is a perspective view showing a state in which each component of FIG. 3 is disassembled. It is sectional drawing of the 2nd intake valve provided in the piston which slides in a cylinder, and the said piston. It is a top view which shows the state by which each component of the piston ring was decomposed | disassembled.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft 1a Rotating plate 2 Crank pin 3 Connecting rod 4 Piston pin 5 Piston 5a Fuel gas passage port 6 Cylinder 7 Primary compression chamber 7a Crankcase assembly 8 Intake port 9 First intake valve 12 Clip 13 Secondary compression chamber 14 Cylinder head 15 Discharge valve 16 Discharge chamber 20 Second intake valve 21, 22 Bearing 23 Valve plate 23a Passing hole 24 Piston ring 24a First ring 24b Second ring 24c, 24d Notch 25 Depressed part 26 Ejecting member 26b Slit 27 Valve body 28 Spring 29 Discharge port 30 Sliding guide 100 Reciprocating compressor

Claims (14)

A reciprocating compressor that compresses fuel gas by driving force from a prime mover,
A cylinder,
A primary compression chamber provided on one end of the cylinder;
A secondary compression chamber provided at the other end of the cylinder;
Introducing means for introducing fuel gas into the primary compression chamber;
Discharging means for discharging fuel gas from the secondary compression chamber;
A piston that compresses the fuel gas in the primary compression chamber and the fuel gas in the secondary compression chamber by reciprocating in the cylinder;
A conversion mechanism provided in the primary compression chamber for converting the driving force into a reciprocating motion of a piston;
A reciprocating compressor comprising supply means for supplying fuel gas compressed in the primary compression chamber into the secondary compression chamber. The reciprocating compressor according to claim 1, wherein the supply unit is provided in the piston. 2. The supply means includes a gas flow path for communicating the primary compression chamber and the secondary compression chamber, and a valve device for bringing the gas flow path into a communication state and a shut-off state. Or the reciprocating compressor of 2. The valve device is
A valve plate having a hole;
The reciprocating compressor according to claim 3, further comprising a valve body that opens and closes the hole based on a difference between the pressure in the primary compression chamber and the pressure in the secondary compression chamber. The primary compression chamber has a fuel gas inlet;
The secondary compression chamber has a fuel gas outlet,
The introduction means includes a first valve provided at the inlet so as to be openable and closable,
The discharging means includes a second valve provided at the outlet so as to be opened and closed,
The first valve and the second valve are opened and closed in accordance with a pressure change in the primary compression chamber and a pressure change in the secondary compression chamber due to reciprocation of the piston. The reciprocating compressor in any one of 1-4. A cylinder head attached to the one end of the cylinder and forming the secondary compression chamber together with the cylinder;
The reciprocating compressor according to claim 1, wherein the discharge unit is provided in the cylinder head. The reciprocating compressor according to claim 1, wherein a volume of the secondary compression chamber is smaller than a volume of the primary compression chamber. The conversion mechanism includes a crank mechanism,
The reciprocating compressor according to claim 1, wherein the primary compression chamber includes a crankcase. The conversion mechanism is
A rotating member that rotates by a driving force from the prime mover;
A connecting member having one end connected to the rotating member and the other end connected to the piston;
The reciprocating compressor according to claim 1, wherein the one end of the connecting member is connected to the rotating member via a first support member made of resin. The conversion mechanism includes a piston pin held by the piston,
The reciprocating compressor according to claim 9, wherein the other end of the connecting member is connected to the piston pin through a second support member made of resin. The reciprocating compressor according to claim 1, further comprising a sliding member that is provided so as to surround an outer peripheral surface of the piston and is made of resin. The reciprocating compressor according to claim 1, further comprising an interposition member attached to the outer peripheral surface of the piston and formed in a ring shape. The reciprocating compressor according to claim 12, wherein the interposition member has a notch. The reciprocating compressor according to claim 13, wherein the interposition member is formed by laminating two or more interposition members having notches in different portions.

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