Compression device and low-temperature liquid supply system

Abstract

This compression device and this low-temperature liquid supply system are configured so that a drive unit and a booster pump driven by the drive unit are provided. The drive unit comprises: a housing with a hollow shape; an eccentric shaft section that is supported within the housing so as to be able to rotate around a first axis oriented in a horizontal direction; a drive motor that can rotate the eccentric shaft section; a rotating body that has a second axis offset from the first axis in a radial direction and that is provided as a single body with an outer peripheral section of the eccentric shaft section; a cross-head that, by being supported within the housing so as to be able to move in a vertical direction, transmits linear reciprocal power to the booster pump; a link section, an upper annular section of which is supported by a first bearing section on an outer peripheral section of the rotating body so as to be able to rotate relatively, and a lower annular section of which is supported by a second bearing on a shaft section of the cross-head so as to be able to rotate; a ventilation hole provided in the housing; and a cooling fin provided on the link section.

Description

Compression equipment and cryogenic fluid supply systems

[0001] The present disclosure relates to a compression device and a cryogenic fluid supply system.

[0002] One system that is being considered to achieve carbon neutrality is to use hydrogen gas as fuel. Hydrogen is stored in a tank in liquid form, and the liquid hydrogen stored in the tank is vaporized to produce hydrogen gas, which is then supplied to, for example, a fuel cell or a hydrogen engine. The hydrogen supply system includes a boost pump that boosts the pressure of the liquid hydrogen. One example of a boost pump is the technology described in Patent Document 1.

[0003] Japanese Patent Application Laid-Open No. 2022-190932

[0004] The boost pump is driven by a drive unit. The drive unit has a drive motor and a drive mechanism. The drive mechanism is, for example, a crank mechanism driven by the drive motor, and the crank mechanism causes a piston to reciprocate inside a cylinder. When the piston reciprocates, the boost pump draws liquid hydrogen into a compression chamber, compresses it, and discharges it. Since the link part of the crank mechanism oscillates due to rotation of the eccentric shaft part, a bearing part is provided between the eccentric shaft part and the link part. Since the bearing part generates heat, it is desirable to provide a cooling mechanism.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a compression device and a cryogenic fluid supply system that improves cooling performance.

[0006] In order to achieve the above-mentioned object, the compression device of the present disclosure includes a drive unit and a boost pump driven by the drive unit, wherein the drive unit includes a hollow housing, an eccentric shaft supported inside the housing so as to be rotatable about a first axis along a horizontal direction, a drive motor capable of rotating the eccentric shaft, a rotor having a second axis radially offset from the first axis and integrally provided on the outer periphery of the eccentric shaft, a crosshead supported so as to be movably vertically inside the housing to transmit linear reciprocating power to the boost pump, a link unit whose upper annular portion is supported on the outer periphery of the rotor by a first bearing portion so as to be rotatable relative to the rotor, and whose lower annular portion is rotatably supported on the shaft portion of the crosshead by a second bearing portion, an air vent provided in the housing, and a cooling fin provided on the link unit.

[0007] The cryogenic fluid supply system of the present disclosure also includes a compressor having the compressor, an evaporator that vaporizes the cryogenic fluid compressed by the compressor, and a dispenser that supplies the gas vaporized by the evaporator.

[0008] According to the compression device and low-temperature fluid supply system of the present disclosure, it is possible to improve cooling performance.

[0009] FIG. 1 is a schematic diagram showing the overall configuration of a hydrogen supply system according to a first embodiment. FIG. 2 is a longitudinal sectional view showing a compression device according to the first embodiment. FIG. 3 is a front view showing a link portion. FIG. 4 is a top view showing a link portion. FIG. 5 is a front view showing a first modified example of the link portion. FIG. 6 is a top view showing a first modified example of the link portion. FIG. 7 is a front view showing a second modified example of the link portion. FIG. 8 is a top view showing a second modified example of the link portion. FIG. 9 is a top view showing a third modified example of the link portion. FIG. 10 is a top view showing a fourth modified example of the link portion. FIG. 11 is a longitudinal sectional view showing a compression device according to a second embodiment. FIG. 12 is a longitudinal sectional view showing a compression device according to a third embodiment.

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0011] First Embodiment <Hydrogen Supply System> FIG. 1 is a schematic diagram showing the overall configuration of a hydrogen supply system according to a first embodiment.

[0012] As shown in FIG. 1 , a hydrogen supply system (low-temperature fluid supply system) 10 supplies (refuels) liquid hydrogen stored in a container 11 as hydrogen gas at a predetermined pressure to a power source of a vehicle 12. Here, the power source is, for example, a fuel cell or a hydrogen engine, and is mounted on the vehicle 12. The hydrogen supply system 10 is, for example, a so-called hydrogen station that supplies (refuels) hydrogen gas, which is a fuel, to the power source of the vehicle 12. However, the hydrogen supply system 10 is not limited to systems that supply hydrogen gas to the power source of the vehicle 12, but also includes systems that supply hydrogen gas to a tank of a trailer that transports hydrogen. Furthermore, the hydrogen supply system 10 is not limited to hydrogen, and it also operates in a similar manner when compressing and supplying a low-temperature fluid (e.g., liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied carbon dioxide, liquefied natural gas, liquefied propane gas, etc.).

[0013] The hydrogen supply system 10 includes a compressor 21, an evaporator 22, and a dispenser 23. The compressor 21 compresses liquid hydrogen (low-temperature fluid) supplied from the container 11 to a predetermined high pressure (high-pressure state). The evaporator 22 generates hydrogen gas by vaporizing the high-pressure liquid hydrogen compressed by the compressor 21. The dispenser 23 fills the power source of the vehicle 12 with the hydrogen gas generated by the evaporator 22.

[0014] Although the compression device 21 compresses the liquid hydrogen stored in the container 11 to a predetermined high pressure, the present invention is not limited to this configuration.

[0015] The compression device 21 has a drive unit 31 and a boost pump 32. The drive unit 31 has a drive motor and a drive mechanism, not shown. The drive motor is an electric motor that can be driven by externally supplied power. The rotation speed of the drive motor is controlled by an inverter (not shown). The drive mechanism has a crank mechanism and converts the rotational power of the drive motor into linear reciprocating power. The drive motor transmits the rotational power to the drive mechanism, and the drive mechanism transmits the linear reciprocating power to the boost pump 32. The boost pump 32 is operated by the drive unit 31 and compresses the liquid hydrogen. The drive unit 31 may have a reducer between the drive motor and the drive mechanism.

[0016] <Compression Device> FIG. 2 is a vertical cross-sectional view showing the compression device of the first embodiment, and FIG. 3 is a front view showing a link portion.

[0017] 2, the compressor 21 has a drive unit 31 and a boost pump 32, and the drive unit 31 has a drive motor 33 and a drive mechanism 34. The compressor 21 (boost pump 32) is a device for boosting the pressure of liquid hydrogen, which is a cryogenic liquid, to a high pressure (approximately 90 MPa).

[0018] <Drive Unit> The drive mechanism 34 has an eccentric shaft unit 41, a rotating body 42, a link unit 43, a connecting unit 44, a crosshead 45, and a housing 46. The drive mechanism 34 has a first bearing unit 47 and a second bearing unit 48.

[0019] The eccentric shaft portion 41 has a cylindrical shape and is disposed along the horizontal direction. The eccentric shaft portion 41 is supported so as to be rotatable about a first axis O1 along the horizontal direction. The tip end of the output shaft 33a of the drive motor 33 is connected to the eccentric shaft portion 41. When the drive motor 33 is driven, the output shaft 33a rotates, and the rotational power of the output shaft 33a is transmitted to the eccentric shaft portion 41, causing the eccentric shaft portion 41 to rotate.

[0020] The rotating body 42 has a disk shape and is disposed outside the eccentric shaft portion 41. The rotating body 42 has a center along the second axis O2, and the center of the rotating body 42 (second axis O2) and the center of the eccentric shaft portion 41 (first axis O1) are radially offset. The first axis O1 and the second axis O2 are parallel. That is, the center of the eccentric shaft portion 41 (first axis O1) is radially eccentric with respect to the center of the rotating body 42 (second axis O2). When the eccentric shaft portion 41 rotates, the rotating body 42 oscillates and rotates about the first axis O1.

[0021] The link portion 43 constitutes a crank mechanism, converts rotational power into linear reciprocating power, and transmits it to the boost pump 32. The link portion 43 has an upper annular portion 43a, a connecting portion 43b, and a lower annular portion 43c. The upper annular portion 43a has a circular ring shape. The upper annular portion 43a is disposed outside the rotor 42 via a first bearing portion 47, and is rotatable relative to the rotor 42. In other words, the rotor 42 and the upper annular portion 43a are supported by the first bearing portion 47 so as to be rotatable relative to each other.

[0022] The lower annular portion 43c has a circular ring shape. The lower annular portion 43c has a center along the third axis O3. The first axis O1, the second axis O2, and the third axis O3 are parallel to each other. The lower annular portion 43c is disposed outside the second bearing portion 48. That is, the lower annular portion 43c is rotatably supported by the second bearing portion 48. The connecting portion 43b is disposed between the upper annular portion 43a and the lower annular portion 43c and integrally connects the upper annular portion 43a and the lower annular portion 43c.

[0023] When the eccentric shaft portion 41 rotates and the rotor 42 swings and rotates about the first axis O1, the link portion 43 is actuated. That is, in the link portion 43, the upper annular portion 43a swings about the first axis O1 due to the rotation of the rotor 42, the swinging force of the upper annular portion 43a is transmitted to the lower annular portion 43c via the connection portion 43b, and the lower annular portion 43c moves linearly back and forth in the vertical direction while rotating about the third axis O3.

[0024] The connecting portion 44 is provided at the upper end of the piston 53 (described later). The connecting portion 44 connects the upper end of the piston 53 to the crosshead 45.

[0025] The crosshead 45 has a cylindrical shape with a bottom that covers the lower annular portion 43c from the outside. The housing 46 has a cylindrical shape with a ceiling and is supported by a stand 49. The crosshead 45 is disposed inside the housing 46. The crosshead 45 is supported so as to be movable vertically relative to the inner surface of the housing 46. The second bearing 48 is provided on the shaft 45a of the crosshead 45. The lower annular portion 43c of the link portion 43 is rotatably supported on the shaft 45a of the crosshead 45 via the second bearing 48. When the eccentric shaft portion 41 and the rotating body 42 rotate and the link portion 43 swings back and forth vertically, the lower annular portion 43c and the crosshead 45 move back and forth vertically relative to the housing 46.

[0026] <Booster Pump> As shown in FIG. 2 , the booster pump 32 includes a casing 51 , a cylinder 52 , and a piston 53 .

[0027] <Casing> The casing 51 is a pressure vessel that stores liquid hydrogen and is also an insulated vacuum vessel. The support plate 61 is arranged horizontally and is installed on the stand 49. The support plate 61 has a through-hole 61a formed in it at a position corresponding to a fourth axis O4 that is along the vertical direction. The casing 51 is an insulated structure that has a cylindrical shape with a bottom, and a liquid storage chamber 62 is formed inside. The upper part of the casing 51 is in close contact with the underside of the support plate 61 and is fastened with bolts. In other words, the upper end of the casing 51 is supported by being suspended from the support plate 61.

[0028] A supply pipe 63 and a gas discharge pipe 64 are connected to the side of the casing 51. The supply pipe 63 is a pipe for supplying liquid hydrogen from an external supply source to the liquid storage chamber 62 of the casing 51. The supply pipe 63 is provided near the bottom of the casing 51. The gas discharge pipe 64 is a pipe for discharging the components (hydrogen gas) vaporized in the liquid storage chamber 62 to the outside. The gas discharge pipe 64 is positioned above and spaced apart from the supply pipe 63. The liquid storage chamber 62 stores liquid hydrogen.

[0029] <Cylinder> The cylinder 52 is a container for compressing liquid hydrogen. The cylinder 52 has a cylindrical shape with a bottom, and a compression chamber 65 is provided at the lower part of the interior. The cylinder 52 has an open upper end. The upper end of the cylinder 52 is connected to a support plate 61. In other words, the upper end of the cylinder 52 is supported by being suspended from the support plate 61.

[0030] An inlet valve 66 is provided at the bottom of the cylinder 52. The inlet valve 66 is used to introduce liquid hydrogen from the liquid reservoir chamber 62 into the compression chamber 65. In other words, the inlet valve 66 is a check valve that opens when the pressure in the compression chamber 65 becomes lower than the pressure in the liquid reservoir chamber 62, allowing the liquid hydrogen from the liquid reservoir chamber 62 to enter the compression chamber 65. On the other hand, when the pressure in the compression chamber 65 becomes higher than the pressure in the liquid reservoir chamber 62, the check valve closes, preventing the liquid hydrogen from the compression chamber 65 from flowing back into the liquid reservoir chamber 62. Note that although FIG. 2 shows the inlet valve 66 exposed to the outside of the cylinder 52, FIG. 2 is a schematic diagram, and in reality the inlet valve 66 is provided inside the cylinder 52.

[0031] A discharge valve 67 is provided on the lower side of the cylinder 52. The discharge valve 67 is used to discharge (exhaust) the high-pressure liquid water compressed in the compression chamber 65 to the outside. That is, the discharge valve 67 is a check valve that opens when the pressure in the compression chamber 65 becomes higher than the pressure on the discharge side, thereby discharging the high-pressure liquid hydrogen in the compression chamber 65 to the outside. On the other hand, when the pressure in the compression chamber 65 becomes lower than the pressure on the discharge side, the discharge valve closes, thereby preventing the high-pressure liquid hydrogen on the discharge side from flowing back into the compression chamber 65. Note that although FIG. 2 shows the discharge valve 67 as exposed to the outside of the cylinder 52, FIG. 2 is a schematic diagram, and in reality the discharge valve 67 is provided inside the cylinder 52.

[0032] A discharge pipe 68 is connected to the discharge valve 67. The discharge pipe 68 is a pipe for discharging high-pressure liquid hydrogen compressed in the compression chamber 35 to the outside. The discharge pipe 68 is arranged adjacent to the cylinder 52 inside the casing 51. The discharge pipe 68 is arranged along the vertical direction, and its lower end is connected to the lower part of the cylinder 52 and communicates with the compression chamber 65 via the discharge valve 67. The upper end of the discharge pipe 68 passes through the top of the casing 51 to extend to the outside, and is supported by the top of the casing 51.

[0033] <Piston> The piston 53 has a shaft portion 53a and a piston body 53b. The piston 53 is configured by connecting the piston body 53b to the lower end of the shaft portion 53a. The piston body 53b has a long, cylindrical shape and is disposed inside the cylinder 52. The piston body 53b is disposed along a fourth axis O4 that is along the vertical direction. The piston body 53b has a constant outer diameter throughout the entire area in the direction of the fourth axis O4. The piston body 53b is connected to the drive unit 31 via the shaft portion 53a. That is, the piston 53 has the piston body 53b connected to the lower end of the shaft portion 53a, and the upper end of the shaft portion 53a extends toward the drive unit 31 through the through-hole 61a and is connected to the connecting portion 44.

[0034] A piston 53 is disposed inside the cylinder 52, thereby defining a compression chamber 65 at the lower end. The piston 53 is reciprocated inside the cylinder 52 along the direction of the fourth axis O4 by the drive unit 31. When the piston 53 moves upward inside the cylinder 52, the volume of the compression chamber 65 expands, the pressure decreases, and liquid hydrogen is drawn in. When the piston 53 moves downward inside the cylinder 52, the volume of the compression chamber 65 contracts, the pressure increases, and the liquid hydrogen is compressed.

[0035] <Air Vents> In the compressor 21, the drive unit 31 has a plurality of air vents 71, 72, and 73. The housing 46 has an upper wall 81, a pair of side wall 82, and a pair of upper corner 83. The upper air vent 71 is provided in the upper wall 81 of the housing 46. A pair of side air vents 72 is provided in each of the side wall 82 of the housing 46. A pair of upper corner air vents 73 is provided in each of the upper corner 83 of the housing 46.

[0036] The upper air vent 71 is provided as a single hole penetrating vertically at the widthwise center of the upper wall 81 of the housing 46, but multiple holes may be provided. The pair of side air vents 72 are provided as a single hole penetrating horizontally through each of the side wall 82 of the housing 46, but multiple holes may be provided. The side air vents 72 are preferably located between the first axis O1, the second axis O2, and the third axis O3. The pair of upper corner air vents 73 are provided as a single hole penetrating diagonally through each of the upper corners 83 of the housing 46, but multiple holes may be provided. Note that the air vents are not limited to the air vents 71, 72, and 73, and may be located at other positions on the housing 46.

[0037] <Cooling Fins> FIG. 3 is a front view showing the link portion, and FIG. 4 is a top view showing the link portion.

[0038] As shown in FIG. 2 , the drive unit 31 of the compression device 21 is provided with cooling fins 91. As shown in FIGS. 3 and 4 , the cooling fins 91 are provided on the link unit 43. Specifically, the cooling fins 91 are provided on the upper annular portion 43a of the link unit 43. In this case, multiple cooling fins 91 are provided at circumferential intervals on the outer periphery of the upper annular portion 43a. The range in which the multiple cooling fins 91 are provided on the outer periphery of the upper annular portion 43a is preferably, for example, within a range of 120 degrees to the left and right of the apex position of the upper annular portion 43a, but is not limited to this range. The cooling fins 91 have a plate shape extending along the axial direction of the upper annular portion 43a. Note that the cooling fins 91 are formed from a metal plate with a constant thickness, but the thickness may gradually increase or decrease. Furthermore, the cooling fins 91 may have an uneven surface or back surface.

[0039] <First Modified Example of Cooling Fins> FIG. 5 is a front view showing a first modified example of the link portion, and FIG. 6 is a top view showing the first modified example of the link portion.

[0040] 5 and 6, the cooling fins 92 are provided on the link portion 43. Specifically, the cooling fins 92 are provided on the upper annular portion 43a of the link portion 43. In this case, a plurality of cooling fins 92 are provided at intervals in the axial direction on the outer periphery of the upper annular portion 43a. The cooling fins 92 have a plate shape curved along the circumferential direction of the upper annular portion 43a. However, the shape of the cooling fins 92 is not limited to a plate shape.

[0041] <Second Modification of Cooling Fins> FIG. 7 is a front view showing a second modification of the link portion, and FIG. 8 is a top view showing the second modification of the link portion.

[0042] 7 and 8, the cooling fins 93 are provided on the link portion 43. Specifically, the cooling fins 93 are provided on the upper annular portion 43a of the link portion 43. In this case, a plurality of cooling fins 93 are provided at intervals in the circumferential direction on the outer periphery of the upper annular portion 43a. The cooling fins 93 are provided at a predetermined inclination angle with respect to the axial direction of the upper annular portion 43a. The cooling fins 93 have a shape that follows the direction of the inclination angle, but are not limited to a plate shape.

[0043] <Third Modification of Cooling Fins> FIG. 9 is a top view showing a third modification of the link portion.

[0044] 9, the cooling fins 94 are provided on the upper annular portion 43a of the link portion 43. In this case, a plurality of cooling fins 94 are provided at intervals in the circumferential direction on the outer periphery of the upper annular portion 43a. The cooling fins 94 are bent at a predetermined angle with respect to the axial direction of the upper annular portion 43a.

[0045] <Fourth Modification of Cooling Fins> FIG. 10 is a top view showing a fourth modification of the link portion.

[0046] 10 , the cooling fins 95 are provided on the upper annular portion 43 a of the link portion 43. In this case, a plurality of cooling fins 95 are provided at intervals in the circumferential direction on the outer periphery of the upper annular portion 43 a. The cooling fins 95 are curved at a predetermined angle relative to the axial direction of the upper annular portion 43 a.

[0047] <Operation of Compressor> As shown in Figure 2, when the drive motor 33 of the drive unit 31 is driven, the eccentric shaft unit 41 rotates, causing the rotor 42 to oscillate and rotate. This then activates the link unit 43, converting the rotational power of the rotor 42 into linear reciprocating power of the crosshead 45, which is then transmitted to the boost pump 32 via the connecting unit 44. The boost pump 32 is operated by the transmitted linear reciprocating power. First, in the suction stroke in which the piston 53 rises, the boost pump 32 draws liquid hydrogen from the casing 51 into the compression chamber 65. Next, in the compression stroke in which the piston 53 descends, the liquid hydrogen in the compression chamber 65 is compressed, and high-pressure liquid hydrogen is discharged into the discharge pipe 68.

[0048] When the drive unit 31 is driven, the eccentric shaft unit 41 and the rotor 42 rotate, causing the upper annular portion 43a of the link unit 43 to swing via the first bearing unit 47. At this time, the first bearing unit 47 receives a load and slides between itself and the rotor 42 and the upper annular portion 43a, generating heat. The lower annular portion 43c of the link unit 43 also swings via the second bearing unit 48. At this time, the second bearing unit 48 receives a load and slides between itself and the lower annular portion 43c, generating heat. When the first bearing unit 47 and the second bearing unit 48 generate heat, the link unit 43 reaches a high temperature. However, because the first bearing unit 47 has cooling fins 91 (92, 93, 94, 95) on the upper annular portion 43a, heat from the link unit 43 is released to the surroundings from the cooling fins 91. The air inside the housing 46 whose temperature has risen due to heat radiation rises inside the housing 46 and is discharged to the outside through the upper vent hole 71 , the side vent hole 72 , and the upper corner vent hole 73 .

[0049] Furthermore, when the drive unit 31 is driven, the link unit 43 reciprocates up and down while the upper annular portion 43a swings back and forth left and right. This causes repeated pressurization and depressurization of the air in the upper space of the housing 46. When the air in the upper space of the housing 46 is pressurized, the pressurized air is forced out through, for example, the upper air vent 71 or the upper corner air vent 73. On the other hand, when the air in the upper space of the housing 46 is depressurized, for example, external air is drawn into the interior through, for example, the side air vent 72.

[0050] When the drive unit 31 is driven, the first bearing unit 47 and the second bearing unit 48 generate heat as they slide under load, but the heat is dissipated by the cooling fins 91 (92, 93, 94, 95), thereby suppressing a temperature rise. Furthermore, the air whose temperature has risen due to heat dissipation from the cooling fins 91 is discharged to the outside through the upper air vent 71, the side air vent 72, and the upper corner air vent 73, thereby suppressing a temperature rise. Therefore, the first bearing unit 47 and the second bearing unit 48 are appropriately cooled, thereby suppressing damage and a reduction in their lifespan.

[0051] [Second embodiment] Fig. 11 is a longitudinal cross-sectional view showing a compression device of a second embodiment. Note that members having the same functions as those in the first embodiment described above are given the same reference numerals, and detailed description thereof will be omitted.

[0052] 11 , the compression device 21A includes a drive unit 31A and a booster pump 32. The drive unit 31A includes a drive motor 33 and a drive mechanism 34A. The drive mechanism 34A includes an eccentric shaft 41, a rotating body 42, a link 43, a connecting portion 44, a crosshead 45A, a housing 46, a first bearing 47, and a second bearing 48. The eccentric shaft 41, the rotating body 42, the link 43, the connecting portion 44, the housing 46, the first bearing 47, and the second bearing 48 have the same configurations as those in the first embodiment.

[0053] In the compression device 21A, the housing 46 is provided with an upper vent hole 71, a side vent hole 72, and an upper corner vent hole 73. The crosshead 45A is provided with a lower vent hole 74. The housing 46 has an upper wall portion 81, a pair of side wall portions 82, and a pair of upper corner portions 83, and is open at the bottom. The crosshead 45A is movably fitted to the housing 46 so as to close the lower opening. The lower vent hole 74 is provided at the bottom of the crosshead 45A. The lower vent hole 74 penetrates the bottom of the crosshead 45A, allowing communication between the inside and outside of the housing 46.

[0054] When the drive unit 31 is driven, the first bearing 47 and the second bearing 48 generate heat as they slide under load, but the heat is dissipated by the cooling fins 91 (92, 93, 94, 95), thereby suppressing temperature rise. When the drive unit 31 is driven, the link unit 43 moves up and down while swinging back and forth left and right, repeatedly pressurizing and depressurizing the air in the upper space of the housing 46. When the air in the upper space of the housing 46 is pressurized, the pressurized air is pushed out through the upper air vent 71, for example. When the air in the upper space of the housing 46 is depressurized, external air is drawn into the interior through the lower air vent 74, for example.

[0055] That is, the air whose temperature has risen due to heat dissipation from the cooling fins 91 is discharged to the outside through the upper ventilation holes 71, and new outside air is introduced through the lower ventilation holes 74, thereby suppressing the temperature rise inside the housing 46. Therefore, the first bearing 47 and the second bearing 48 are appropriately cooled, thereby suppressing damage and reducing a reduction in their lifespan.

[0056] 12 is a longitudinal cross-sectional view showing a compression device according to a third embodiment. Note that members having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0057] 12 , the compression device 21B includes a drive unit 31B and a booster pump 32. The drive unit 31B includes a drive motor 33 and a drive mechanism 34B. The drive mechanism 34B includes an eccentric shaft 41, a rotating body 42, a link 43, a connecting portion 44, a crosshead 45B, a housing 46, a first bearing 47, and a second bearing 48. The eccentric shaft 41, the rotating body 42, the link 43, the connecting portion 44, the housing 46, the first bearing 47, and the second bearing 48 have the same configurations as those in the first embodiment.

[0058] In the compression device 21B, the housing 46 is provided with an upper vent hole 71, a side vent hole 72, and an upper corner vent hole 73. The crosshead 45B is provided with a lower vent hole 74. The housing 46 has an upper wall portion 81, a pair of side wall portions 82, and a pair of upper corner portions 83, and is open at the bottom. The crosshead 45B is movably fitted to the housing 46 so as to close the lower opening. The lower vent hole 74 is provided at the bottom of the crosshead 45B. The lower vent hole 74 penetrates the bottom of the crosshead 45B, allowing communication between the inside and outside of the housing 46. Two lower vent holes 74 are provided in the crosshead 45B, but the number is not limited.

[0059] The upper vent hole 71 is provided with an upper check valve 101, and the lower vent hole 74 is provided with a lower check valve 102. The upper check valve 101 only allows exhaust and prevents intake. The lower check valve 102 only allows intake and prevents exhaust. In other words, the upper check valve 101 allows air to flow from the inside of the housing 46 to the outside, but prevents air from flowing from the outside of the housing 46 to the inside. The lower check valve 102 allows air to flow from the outside of the housing 46 to the inside, but prevents air from flowing from the inside of the housing 46 to the outside.

[0060] When the drive unit 31 is driven, the first bearing 47 and the second bearing 48 generate heat as they slide under load, but the heat is dissipated by the cooling fins 91 (92, 93, 94, 95), thereby suppressing temperature rise. When the drive unit 31 is driven, the link unit 43 reciprocates up and down while swinging back and forth left and right, repeatedly pressurizing and decompressing the air in the upper space of the housing 46. When the air in the upper space of the housing 46 is pressurized, the pressurized air is pushed out through the upper check valve 101 of the upper air vent 71 to the outside. When the air in the upper space of the housing 46 is depressurized, external air is drawn into the interior through the lower check valve 102 of the lower air vent 74.

[0061] That is, air whose temperature has risen due to heat dissipation from the cooling fins 91 is discharged to the outside through the upper check valve 101 of the upper air vent 71, and new outside air is introduced through the lower check valve 102 of the lower air vent 74, thereby suppressing a rise in temperature inside the housing 46. Therefore, the first bearing 47 and the second bearing 48 are appropriately cooled, thereby suppressing damage and a reduction in their lifespan.

[0062] [Operation and Effect of the Present Embodiment] The compressor according to the first aspect includes a drive unit 31, 31A, 31B, and a booster pump 32 driven by the drive unit 31, 31A, 31B. The drive unit 31, 31A, 31B includes a hollow housing 46, an eccentric shaft unit 41 supported rotatably around a first axis O1 extending horizontally inside the housing 46, a drive motor 33 capable of rotating the eccentric shaft unit 41, a rotor 42 having a second axis O2 radially offset from the first axis O1 and integrally provided on the outer periphery of the eccentric shaft unit 41, and a lead-type rotor 43 mounted inside the housing 46. The crossheads 45, 45A, 45B are supported so as to be freely movable in the vertical direction, thereby transmitting linear reciprocating power to the boost pump 32; an upper annular portion 43a is supported so as to be freely rotatable relative to the outer periphery of the rotating body 42 by a first bearing portion 47, and a lower annular portion 43c is supported so as to be freely rotatable on the shaft portion 45a of the crossheads 45, 45A, 45B by a second bearing portion 48; ventilation holes 71, 72, 73 are provided in the housing 46; and cooling fins 91, 92, 93, 94, 95 are provided on the link portion 43.

[0063] In the compression device according to the first aspect, when the drive unit 31 is driven, the first bearing unit 47 and the second bearing unit 48 generate heat as they slide under load, but the heat is dissipated by the cooling fins 91, 92, 93, 94, and 95, thereby suppressing the temperature rise. The air whose temperature has risen due to heat dissipation from the cooling fins 91, 92, 93, 94, and 95 is then discharged to the outside through the air vents 71, 72, and 73, thereby suppressing the temperature rise. This improves the cooling performance of the first bearing unit 47 and the second bearing unit 48.

[0064] The compression device according to the second aspect is the compression device according to the first aspect, and further includes cooling fins 91, 92, and 93 provided on the upper annular portion 43 a, thereby enabling the first bearing portion 47 and the second bearing portion 48 to be cooled efficiently.

[0065] The compression device according to the third aspect is the compression device according to the second aspect, further comprising a plurality of cooling fins 91, 93, 94, 95 provided at intervals in the circumferential direction on the outer periphery of the upper annular portion 43 a, thereby enabling heat from the first bearing portion 47 and the second bearing portion 48 to be efficiently dissipated from the upper annular portion 43 a.

[0066] The compression device according to the fourth aspect is the compression device according to the second or third aspect, further comprising: cooling fins 93 provided at a predetermined inclination angle relative to the axial direction, thereby enabling heat from the first bearing 47 and the second bearing 48 to be efficiently dissipated from the upper annular portion 43 a.

[0067] The compression device according to the fifth aspect is the compression device according to the second aspect, further comprising a plurality of cooling fins 92 provided at intervals in the axial direction on the outer periphery of the upper annular portion 43 a, thereby enabling heat from the first bearing portion 47 and the second bearing portion 48 to be efficiently dissipated from the upper annular portion 43 a.

[0068] The compressor according to the sixth aspect is the compressor according to any one of the first to fifth aspects, and further includes an upper vent hole 71 provided in an upper wall portion 81 of the housing 46, a side vent hole 72 provided in a side wall portion 82 of the housing 46, and an upper corner vent hole 73 provided in an upper corner portion 83 of the housing 46. This allows high-temperature air inside the housing 46 to be efficiently exhausted to the outside.

[0069] A compression device according to a seventh aspect is the compression device according to any one of the first to sixth aspects, further comprising lower air vents 74 provided below the crossheads 46A, 46B. As a result, air whose temperature has increased due to heat radiation from the cooling fins 91, 92, 93, 94 rises inside the housing 46 and is discharged to the outside through the upper air vents 71, while new outside air is introduced through the lower air vents 74, thereby suppressing the temperature increase inside the housing 46.

[0070] The compressor according to an eighth aspect is the compressor according to any one of the first to seventh aspects, further comprising an upper vent hole 71 and a lower vent hole 74, with the upper vent hole 71 being provided with an upper check valve 101 that allows only exhaust air, and the lower vent hole 74 being provided with a lower check valve 102 that allows only intake air. As a result, air whose temperature has increased due to heat radiation from the cooling fins 91, 92, 93, 94 is discharged to the outside through the upper check valve 101 of the upper vent hole 71, while new outside air is introduced through the lower check valve 102 of the lower vent hole 74, thereby suppressing a temperature increase inside the housing 46.

[0071] A hydrogen supply system (low-temperature fluid supply system) according to the ninth aspect includes a compressor 21, 21A, 21B according to any one of the first to eighth aspects, an evaporator 22 that vaporizes liquid hydrogen (low-temperature fluid) compressed by the compressor 21, 21A, 21B, and a dispenser 23 that supplies hydrogen gas vaporized by the evaporator 22. This enables the drive units 31, 31A, 31B of the compressors 21, 21A, 21B to improve the cooling performance of the first bearing 47 and the second bearing 48.

[0072] REFERENCE SIGNS LIST 10 Hydrogen supply system (low-temperature fluid supply system) 11 Container 12 Vehicle 21, 21A, 21B Compressor 22 Evaporator 23 Dispenser 31, 31A, 31B Drive unit 32 Booster pump 33 Drive motor 34, 34A, 34B Drive mechanism 41 Eccentric shaft 42 Rotor 43 Link 44 Connection 45, 45A, 45B Crosshead 46 Housing 47 First bearing 48 Second bearing 49 Frame 51 Casing 52 Cylinder 53 Piston 61 Support plate 62 Liquid storage chamber 63 Supply pipe 64 Gas discharge pipe 65 Compression chamber 66 Intake valve 67 Discharge valve 68 Discharge piping 71 Upper vent 72 Side vent 73 Upper corner vent hole 74 Lower vent hole 81 Upper wall portion 82 Side wall portion 83 Upper corner portion 91, 92, 93, 94, 95 Cooling fins 101 Upper check valve 102 Lower check valve O1 First axis O2 Second axis O3 Third axis O4 Fourth axis

Claims

1. A compression device comprising: a drive unit; and a boost pump driven by the drive unit, wherein the drive unit comprises: a hollow housing; an eccentric shaft supported within the housing for rotation about a first axis along a horizontal direction; a drive motor capable of rotating the eccentric shaft; a rotor having a second axis radially offset from the first axis and integrally provided on the outer periphery of the eccentric shaft; a crosshead supported for movement along a vertical direction within the housing to transmit linear reciprocating power to the boost pump; a link unit having an upper annular portion rotatably supported on the outer periphery of the rotor by a first bearing portion and a lower annular portion rotatably supported on the shaft portion of the crosshead by a second bearing portion; air vents provided in the housing; and a cooling fin provided on the link unit.

2. The compressor according to claim 1, wherein the cooling fins are provided on the upper annular portion.

3. The compression device according to claim 2, wherein a plurality of the cooling fins are provided at intervals in the circumferential direction on the outer periphery of the upper annular portion.

4. The compressor according to claim 3, wherein the cooling fins are provided at a predetermined inclination angle with respect to the axial direction.

5. The compression device according to claim 2, wherein a plurality of the cooling fins are provided at intervals in the axial direction on the outer periphery of the upper annular portion.

6. The compressor according to claim 1, wherein the vent holes include upper vent holes provided in the upper wall portion of the housing, side vent holes provided in the side wall portion of the housing, and upper corner vent holes provided in the upper corners of the housing.

7. The compression device according to claim 1, wherein the vent hole includes a lower vent hole provided in the lower part of the crosshead.

8. The compressor according to claim 1, wherein the vent hole has an upper vent hole and a lower vent hole, the upper vent hole being provided with an upper check valve that allows only exhaust air to pass through, and the lower vent hole being provided with a lower check valve that allows only intake air to pass through.

9. A cryogenic fluid supply system comprising: a compressor having the compressor according to claim 1; an evaporator for evaporating the cryogenic fluid compressed by the compressor; and a dispenser for supplying the gas evaporated by the evaporator.

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