Compression device, low-temperature fluid supply system, and oil supply method for compression device

Abstract

The present invention comprises a drive part and a booster pump driven by the drive part. The drive part has: a housing having a hollow shape and supported at a lower part thereof by a frame; an eccentric shaft part supported inside the housing so as to be free to rotate about a first axis along a horizontal direction; a drive motor capable of rotating the eccentric shaft part; a rotary body which has a second axis offset from the first axis in the radial direction and which is integrally provided on an outer peripheral part of the eccentric shaft part; a crosshead that transmits linear reciprocating motive power to a piston of the booster pump by being supported inside the housing so as to be free to move along a vertical direction; a link part having an upper annular part supported so as to rotate freely relative to an outer peripheral part of the rotary body and having a lower annular part coupled so as to rotate freely about a shaft part of the crosshead along the horizontal direction; and a bearing part which is disposed between the lower annular part and the shaft part and which is provided with an oil supply part at a lower part thereof. The housing is detachably coupled to the frame, and the crosshead is detachably coupled to the piston.

Description

Compression device, cryogenic fluid supply system, and oil supply method for compression device

[0006] ,

[0001] The present disclosure relates to a compression device, a cryogenic fluid supply system, and an oil supply method for a compression device.

[0002] As a system for achieving carbon neutrality, it is considered to apply hydrogen gas as fuel. Hydrogen is stored in a tank in the state of liquid hydrogen, the liquid hydrogen stored in the tank is vaporized into hydrogen gas, and the hydrogen gas is supplied to, for example, a fuel cell or a hydrogen engine. The hydrogen supply system includes a booster pump for boosting the pressure of liquid hydrogen. As the booster pump, for example, there is the technique described in Patent Document 1.

[0003] Japanese Unexamined Patent Application Publication No. 2024-76751

[0004] The booster pump is driven by a drive unit. The drive unit has a drive motor and a drive mechanism. The drive mechanism has, for example, a crank mechanism driven by a drive motor, and a piston reciprocates inside a cylinder due to the operation of the crank mechanism. The booster pump sucks and compresses liquid hydrogen into a compression chamber and discharges it when the piston reciprocates. Since the link portion swings due to the rotation of the eccentric shaft portion in the crank mechanism, a bearing portion is provided between the eccentric shaft portion and the link portion. Lubrication is required for the bearing portion to reduce friction and wear. As lubrication methods for the bearing portion, for example, there are oil lubrication and grease lubrication. When oil lubrication is applied to lubricate the drive unit of the booster pump, there is a risk that the leaked oil may mix into the hydrogen gas. On the other hand, when grease lubrication is applied to lubricate the drive unit of the booster pump, it is difficult to inject grease lubrication into the crank mechanism arranged inside the housing, and in order to inject grease lubrication into the crank mechanism, it was necessary to remove the crank mechanism from the housing by disassembling the drive unit.

[0005] The present disclosure solves the above-described problems, and an object thereof is to provide a compression device, a cryogenic fluid supply system, and an oil supply method for a compression device that enable appropriate oil supply to the drive unit.

[0006] A compression device of the present disclosure for achieving the above objectives comprises a drive unit and a booster pump driven by the drive unit, wherein the drive unit comprises a housing having a hollow shape with its lower part supported on a frame, an eccentric shaft portion rotatably supported within the housing about a first axis along the horizontal direction, a drive motor capable of rotating the eccentric shaft portion, a rotating body integrally provided on the outer circumference of the eccentric shaft portion having a second axis radially offset from the first axis, a crosshead supported within the housing so as to be movable along the vertical direction, thereby transmitting linear reciprocating power to the piston of the booster pump, a link portion whose upper annular portion is supported so as to be rotatably relative to the outer circumference of the rotating body and whose lower annular portion is rotatably connected about an axis portion along the horizontal direction of the crosshead, and a bearing portion disposed between the lower annular portion and the axis portion and having a lubrication portion at its lower part, wherein the housing is detachably connected to the frame and the crosshead is detachably connected to the piston.

[0007] Furthermore, the cryogenic fluid supply system of this disclosure comprises 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] Furthermore, the method for lubricating a compressor according to the present disclosure comprises a drive unit having a crank mechanism and a booster pump disposed below the drive unit and having a piston that reciprocates linearly by the crank mechanism, and the method for lubricating a compressor comprises the steps of: releasing the connection between the housing of the drive unit and the support frame; releasing the connection between the drive unit and the piston; lifting the drive unit relative to the booster pump; and supplying lubricant to the bearing portion of the crank mechanism from below the housing.

[0009] According to the compressor, cryogenic fluid supply system, and lubrication method for the compressor described herein, lubrication can be properly supplied to the drive unit.

[0010] Figure 1 is a schematic diagram showing the overall configuration of the hydrogen supply system of this embodiment. Figure 2 is a longitudinal cross-sectional view showing the compressor of this embodiment. Figure 3 is a cross-sectional view taken along line III-III in Figure 2, showing the compressor of this embodiment. Figure 4 is a cross-sectional view showing the third bearing section. Figure 5 is a cross-sectional view taken along line V-V in Figure 4, showing the oil supply passage. Figure 6 is a cross-sectional view taken along line VI-VI in Figure 5, showing the shape of the oil supply passage. Figure 7 is a schematic diagram showing the method of supplying oil to the third bearing section. Figure 8 is a schematic diagram showing the method of supplying oil to the third bearing section.

[0011] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. However, these embodiments do not limit the present disclosure, and where there are multiple embodiments, they may be combinations of these embodiments. Furthermore, the components in the embodiments include those readily conceivable by those skilled in the art, those that are substantially identical, and those that are equivalent.

[0012] [Embodiment] <Hydrogen Supply System> Figure 1 is a schematic diagram showing the overall configuration of the hydrogen supply system of the first embodiment.

[0013] As shown in Figure 1, the hydrogen supply system (low-temperature fluid supply system) 10 supplies (replenishes) liquid hydrogen stored in a container 11 as hydrogen gas at a predetermined pressure to the power source of the 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 (replenishes) hydrogen gas, which is the fuel, to the power source of the vehicle 12. However, the hydrogen supply system 10 is not limited to supplying hydrogen gas to the power source of the vehicle 12, but also includes supplying hydrogen gas to the tank of a trailer for transporting hydrogen. Furthermore, the hydrogen supply system 10 operates similarly when supplying compressed low-temperature fluids (for example, liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied carbon dioxide, liquefied natural gas, liquefied propane gas, etc.) rather than just hydrogen.

[0014] 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.

[0015] The compression device 21 compressed the liquid hydrogen stored in the container 11 to a predetermined high pressure, but the configuration is not limited to this.

[0016] The compression device 21 comprises a drive unit 31 and a booster pump 32. The drive unit 31, although not shown, comprises a drive motor and a drive mechanism. The drive motor is an electric motor that can be driven by power supplied from an external source. The rotational 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 booster pump 32. The booster pump 32 is operated by the drive unit 31 and compresses liquid hydrogen. The drive unit 31 may have a reduction gear between the drive motor and the drive mechanism.

[0017] <Compression Device> Figure 2 is a longitudinal cross-sectional view showing the compression device of the first embodiment, and Figure 3 is a cross-sectional view taken along line III-III in Figure 2 showing the compression device of this embodiment.

[0018] As shown in Figures 2 and 3, the compression device 21 includes a drive unit 31 and a booster pump 32, and the drive unit 31 includes a drive motor 33 and a drive mechanism 34. The compression device 21 (boostering pump 32) is a device for increasing the pressure of liquid hydrogen, which is an extremely cold liquid, to high pressure (approximately 90 MPa).

[0019] <Drive Unit> The drive mechanism 34 includes an eccentric shaft 41, a rotating body 42, a link 43, a connecting part 44, a crosshead 45, and a housing 46.

[0020] The eccentric shaft portion 41 is cylindrical in shape and arranged along the horizontal direction. The eccentric shaft portion 41 is rotatably supported about a first axis O1 that lies along the horizontal direction. The eccentric shaft portion 41 is located on the upper part of the housing 46. The eccentric shaft portion 41 penetrates the upper part of the housing 46 horizontally and is rotatably supported by a pair of first bearing portions (self-aligning bearings) 101, 102. The tip 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.

[0021] The rotating body 42 is disc-shaped, positioned outside the eccentric shaft portion 41, and rotatable integrally with 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 offset radially (vertical direction in Figure 2). 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 located 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 around the first axis O1.

[0022] The link section 43 constitutes a crank mechanism and converts rotational power into linear reciprocating power, which is then transmitted to the boost pump 32. The link section 43 has an upper annular section 43a, a connecting section 43b, and a lower annular section 43c. The upper annular section 43a has a ring shape. The upper annular section 43a is positioned on the outside of the rotating body 42 via a second bearing section (self-aligning bearing) 103 and is rotatable relative to the rotating body 42. That is, the rotating body 42 and the upper annular section 43a are supported by the second bearing section 103 so as to be able to rotate relative to each other.

[0023] The lower annular portion 43c has an annular 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. The lower annular portion 43c is supported by the shaft portion 105 via the third bearing portion (needle bearing) 104. That is, the lower annular portion 43c is rotatably supported by the shaft portion 105 via the third bearing portion 104. The shaft portion 105 is along the third axis O3. The connecting portion 43b is positioned 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.

[0024] When the eccentric shaft portion 41 rotates and the rotating body 42 oscillates around the first axis O1, the link portion 43 is activated. Specifically, the upper annular portion 43a of the link portion 43 oscillates around the first axis O1 due to the rotation of the rotating body 42, and the oscillating power of the upper annular portion 43a is transmitted to the lower annular portion 43c via the connecting portion 43b, causing the lower annular portion 43c to reciprocate linearly in the vertical direction while rotating around the third axis O3.

[0025] The connecting portion 44 is provided at the upper end of the piston 53, which will be described later. The connecting portion 44 connects the upper end of the piston 53 to the crosshead 45.

[0026] The crosshead 45 has a hollow shape that covers the lower annular portion 43c of the link portion 43 from the outside. The crosshead 45 has a cylindrical portion 45a, a top portion 45b, and a bottom portion 45c. The top portion 45b and the bottom portion 45c have openings that penetrate vertically, and a third bearing portion 104 is arranged therein. The third bearing portion 104 has an inner circumference shaft portion 105. The shaft portion 105 has each axial end that penetrates the cylindrical portion 45a.

[0027] The housing 46 is supported by the frame 111. The housing 46 has a housing body 46a and a base 46b. The housing body 46a has a cylindrical shape with a top section. The base 46b has a horizontal plate shape. The housing body 46a is placed on the base 46b and is detachably fixed by a plurality of bolts 112. The housing 46 has its base 46b placed on the frame 111 and is fixed by a plurality of bolts 113. In other words, the housing body 46a is detachably attached to the base 46b which is fixed to the frame 111.

[0028] The housing 46 has a crosshead 45 positioned inside. The crosshead 45 is supported so as to be movable vertically relative to the inner surface of the cylindrical portion 45a in the housing 46. The lower annular portion 43c of the link portion 43 is rotatably connected to the shaft portion 105 of the crosshead 45 via the third bearing portion 104. When the eccentric shaft portion 41 and the rotating body 42 rotate and the link portion 43 reciprocates vertically, the lower annular portion 43c and the crosshead 45 reciprocate vertically relative to the housing 46.

[0029] Furthermore, a crosshead cover 106 is positioned at the bottom of the crosshead 45. The crosshead cover 106 is disc-shaped and positioned horizontally. The crosshead cover 106 is movably fitted to the bottom of the housing 46, fits tightly to the bottom 45c of the crosshead 45, and is detachably attached by a plurality of bolts 107. The connecting portion 44 penetrates from the top to the bottom of the crosshead cover 106, and its tip is connected to the upper end of the piston 53. Therefore, when the crosshead cover 106 is removed from the crosshead 45, the crosshead 45 is disconnected from the piston 53 of the booster pump 32. The housing 46 is provided with a work opening 108 at its bottom. The work opening 108 allows access from outside the housing 46 to the connecting portion between the crosshead 45 and the piston 53, that is, the plurality of bolts 107 connecting the crosshead cover 106 and the crosshead 45.

[0030] <Booster Pump> As shown in Figure 2, the boost pump 32 comprises a casing 51, a cylinder 52, and a piston 53.

[0031] The casing 51 is a pressure vessel for storing liquid hydrogen and is also an insulated vacuum vessel. The upper end of the casing 51 is supported by a base 46b of the housing 46. The base 46b is arranged horizontally and installed on the frame 111. The base 46b has a through hole located along the fourth axis O4 in the vertical direction. The casing 51 is an insulated structure with a bottomed cylindrical shape, and a liquid storage chamber 62 is formed inside. The flange portion at the upper end of the casing 51 is in close contact with the lower surface of the base 46b and fastened with bolts. That is, the upper end of the casing 51 is suspended and supported by the housing 46.

[0032] The casing 51 has a supply pipe 63 and a gas discharge pipe 64 connected to its side. The supply pipe 63 is a pipe for supplying liquid hydrogen from an external source to the liquid storage chamber 62 of the casing 51. The supply pipe 63 is located near the bottom of the casing 51. The gas discharge pipe 64 is a pipe for discharging the vaporized components (hydrogen gas) from the liquid storage chamber 62 to the outside. The gas discharge pipe 64 is located above and spaced apart from the supply pipe 63. The liquid storage chamber 62 stores liquid hydrogen.

[0033] The cylinder 52 is a container for compressing liquid hydrogen. The cylinder 52 has a bottomed cylindrical shape, and a compression chamber 65 is provided on the lower side inside. The upper end of the cylinder 52 is open. The upper end of the cylinder 52 is connected to the base 46b. That is, the upper end of the cylinder 52 is suspended and supported by the housing 46.

[0034] A suction valve 66 is provided at the bottom of the cylinder 52. The suction valve 66 is for introducing liquid hydrogen from the liquid storage chamber 62 into the compression chamber 65. In other words, the suction valve 66 is a check valve and opens when the pressure in the compression chamber 65 is lower than the pressure in the liquid storage chamber 62, allowing liquid hydrogen from the liquid storage chamber 62 to be introduced into the compression chamber 65. On the other hand, it closes when the pressure in the compression chamber 65 is higher than the pressure in the liquid storage chamber 62, preventing liquid hydrogen from the compression chamber 65 from flowing back into the liquid storage chamber 62. In Figure 2, the suction valve 66 is shown exposed outside the cylinder 52, but Figure 2 is a schematic diagram, and in reality, the suction valve 66 is provided inside the cylinder 52.

[0035] A discharge valve 67 is provided on the lower side of cylinder 52. The discharge valve 67 is for discharging (releasing) the high-pressure liquid water compressed in the compression chamber 65 to the outside. In other words, the discharge valve 67 is a check valve and opens when the pressure in the compression chamber 65 becomes higher than the pressure on the discharge side, discharging the high-pressure liquid hydrogen from the compression chamber 65 to the outside. On the other hand, it closes when the pressure in the compression chamber 65 becomes lower than the pressure on the discharge side, preventing the high-pressure liquid hydrogen from the discharge side from flowing back into the compression chamber 65. In Figure 2, the discharge valve 67 is shown exposed to the outside of cylinder 52, but Figure 2 is a schematic diagram, and in reality, the discharge valve 67 is provided inside cylinder 52.

[0036] The discharge valve 67 is connected to the discharge pipe 68. The discharge pipe 68 is a pipe for discharging the high-pressure liquid hydrogen compressed in the compression chamber 35 to the outside. The discharge pipe 68 is located inside the casing 51, adjacent to the cylinder 52. The discharge pipe 68 is arranged vertically, its lower end is connected to the bottom of the cylinder 52, and it communicates with the compression chamber 65 via the discharge valve 67. The upper end of the discharge pipe 68 extends to the outside, passing through the top of the casing 51.

[0037] The piston 53 has a shaft portion 53a and a piston body 53b. The piston 53 is constructed by connecting the piston body 53b to the lower end of the shaft portion 53a. The piston body 53b has an elongated cylindrical shape and is arranged inside the cylinder 52. The piston body 53b is arranged along a fourth axis O4 that runs vertically. The outer diameter of the piston body 53b is constant over 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 towards the drive unit 31 through the through hole a and is connected to the connecting portion 44.

[0038] The cylinder 52 has a piston 53 positioned inside, which divides the lower end into a compression chamber 65. The piston 53 reciprocates 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.

[0039] <Operation of the Compressor> As shown in Figures 2 and 3, when the drive motor 33 of the drive unit 31 is driven, the eccentric shaft 41 rotates and the rotating body 42 oscillates. Then the link 43 operates, and the rotational power of the rotating body 42 is converted into linear reciprocating power of the crosshead 45, and the linear reciprocating power is transmitted to the booster pump 32 via the connecting part 44. The booster pump 32 operates using the transmitted linear reciprocating power. First, in the suction step in which the piston 53 rises, liquid hydrogen in the casing 51 is drawn into the compression chamber 65. Next, in the compression step 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.

[0040] <Lubrication of Bearing Sections> As shown in Figures 2 and 3, the first bearing sections 101 and 102, the second bearing section 103, and the third bearing section 104 require lubrication. The first bearing sections 101 and 102, the second bearing section 103, and the third bearing section 104 are lubricated with grease. The first bearing sections 101 and 102 and the second bearing section 103 are self-aligning bearings, and the third bearing section 104 is a needle bearing. Therefore, the type of grease used for the first bearing sections 101 and 102 and the second bearing section 103 is different from the type of grease used for the third bearing section 104.

[0041] Also, grease lubrication requires replenishment of grease to the bearing parts 101, 102, 103, 104 at regular intervals. The first bearing parts 101, 102 are arranged on the upper side of the housing 46, and the housing 46 is provided with oil supply holes 121, 122. Therefore, the first bearing parts 101, 102 are replenished with grease from the outside through the oil supply holes 121, 122. Further, the second bearing part 103 is arranged on the upper part of the housing 46, and an oil supply opening 123 is provided in the upper part of the housing 46, and a lid part 124 for opening and closing the oil supply opening 123 is provided. Therefore, an oil supply gun (not shown) is inserted into the second bearing part 103 through the oil supply opening 123, and the grease is replenished to the oil supply part 103a.

[0042] Since the third bearing part 104 is arranged inside the housing 46, it is difficult to replenish grease from the outside. Therefore, after separating the drive part 31 and the booster pump 32, grease is replenished to the third bearing part 104.

[0043] <Structure of the third bearing part> FIG. 4 is a cross-sectional view showing the third bearing part.

[0044] As shown in FIG. 4, the third bearing part 104 has two needle bearings 131, 132. The two needle bearings 131, 132 have the same configuration and are arranged in series along the axial direction. However, the number of the needle bearings 131, 132 is not limited to two, and may be one or three or more. Each of the needle bearings 131, 132 has an outer ring 131a, 132a, an inner ring 131b, 132b, and a plurality of rollers 131c, 132c. The outer rings 131a, 132a and the inner rings 131b, 132b have a cylindrical shape, and a gap is formed between them. The plurality of rollers 131c, 132c are arranged between the outer rings 131a, 132a and the inner rings 131b, 132b. The outer rings 131a, 132a are connected to the inner peripheral part of the lower annular part 43c of the link part 43 at the outer peripheral part. The inner rings 131b, 132b are connected to the shaft part 105 at the inner peripheral part.

[0045] The needle bearings 131 and 132 have an outer spacer 133 and an inner spacer 134 disposed therebetween. The outer spacer 133 and the inner spacer 134 are in a ring shape. The inner spacer 134 is disposed on the inner peripheral side of the outer spacer 133. The outer spacer 133 is disposed between the outer rings 131a and 132a, and the inner spacer 134 is disposed between the inner rings 131b and 132b. Further, dust seals 135 and 136 are disposed on the outer side in the axial direction of the needle bearings 131 and 132. The dust seals 135 and 136 are in a ring shape, and the outer peripheral portion is fixed to the end portion of the lower annular portion 43c of the link portion 43 by a plurality of bolts 137 and 138, and the inner peripheral portion is fitted movably relative to the disk portions 139 and 140 fixed to the bottom portion 45c of the cross head 45. Therefore, when the link portion 43 swings with respect to the shaft portion 105, the dust seals 135 and 136 swing together with the lower annular portion 43c, and can always cover the gap between the outer rings 131a and 132a and the inner rings 131b and 132b from the outside.

[0046] The third bearing portion 104 has the second bearing portion 103 disposed above it. The grease of the third bearing portion 104 and the grease of the second bearing portion 103 are of different types. When the drive unit 31 operates, the grease of the second bearing portion 103 may melt and flow downward and mix into the third bearing portion 104. At this time, since the dust seals 135 and 136 cover the gap between the outer rings 131a and 132a and the inner rings 131b and 132b, the mixing of the grease of the second bearing portion 103 is suppressed.

[0047] <Lubrication of the Third Bearing Portion> Fig. 5 is a V-V cross-sectional view of Fig. 4 showing the oil supply passage, and Fig. 6 is a VI-VI cross-sectional view of Fig. 5 showing the shape of the oil supply passage.

[0048] As shown in Figs. 4 and 5, the outer spacer 133 and the inner spacer 134 are disposed between the needle bearings 131 and 132. The outer spacer 133 is disposed so as to contact the inner spacer 134 on the inner peripheral surface. The outer spacer 133 is provided with an oil supply passage 141. The oil supply passage 141 has an oil supply portion 142, an oil supply groove 143, a first oil supply hole 144, and a second oil supply hole 145.

[0049] As shown in Figures 5 and 6, the oil supply section 142 is provided at the lower part of the outer circumference of the outer spacer 133. An oil supply gun (not shown) can be connected to the oil supply section 142. The oil supply section 142 is not provided at the very bottom of the outer circumference of the outer spacer 133, but at a position moved upward by a predetermined angle from the very bottom. However, the oil supply section 142 may also be provided at the very bottom of the outer circumference of the outer spacer 133. The oil supply groove 143 is provided along the circumferential direction on the outer circumference of the outer spacer 133. The oil supply groove 143 is provided along the entire circumference on the outer surface of the outer spacer 133. The oil supply section 142 communicates with the oil supply groove 143.

[0050] The first oil supply hole 144 is provided on the upper outer circumference of the outer spacer 133. Multiple first oil supply holes 144 are provided (three in this embodiment), but the number is not limited and one or more is sufficient. The first oil supply holes 144 are provided at the uppermost part of the outer circumference of the outer spacer 133 and at a position moved downward by a predetermined angle from the uppermost part. The first oil supply hole 144 is provided radially along the upper outer circumference of the outer spacer 133. The first oil supply hole 144 communicates with an oil supply groove 143 provided in the outer spacer 133 and extends to the middle of the inner circumference of the outer spacer 133. The second oil supply hole 145 is provided on both sides in the thickness direction of the inner circumference of the outer spacer 133. The second oil supply hole 145 communicates with the first oil supply hole 144 and the needle bearings 131 and 132. The second lubrication hole 145 is inclined from the first lubrication hole 144 toward the inner rings 131b and 132b of the needle bearings 131 and 132.

[0051] The lubrication passage 141 is a passage for supplying grease to the needle bearings 131 and 132 from the outside. The lubrication section 142, lubrication groove 143, first lubrication hole 144, and second lubrication hole 145 that constitute the lubrication passage 141 are in communication with each other. The lubrication passage 141 can supply the grease supplied to the lubrication section 142 to the needle bearings 131 and 132 via the lubrication groove 143, the first lubrication hole 144, and the second lubrication hole 145.

[0052] <Lubrication Method for the Third Bearing Section> Figures 7 and 8 are schematic diagrams illustrating the lubrication method for the third bearing section.

[0053] As shown in Figures 2 and 3, the compressor 21 has a drive unit 31 and a booster pump 32, and the drive unit 31 is detachably attached to the booster pump 32. Specifically, in the drive unit 31, the housing 46 has a housing body 46a and a base 46b. The base 46b is fixed to the frame 111 by bolts 113, and the housing body 46a is detachably connected to the base 46b by bolts 112. In the booster pump 32, the upper end of the piston 53 is connected to the crosshead cover 106 by a connecting part 44, and the crosshead cover 106 is detachably connected to the lower part of the crosshead 45 by bolts 107. The housing 46 is provided with a working opening 108 that can be inserted from the outside into the connection between the crosshead 45 and the piston 53.

[0054] When supplying grease to the third bearing section 104 from the outside, the drive unit 31 is removed from the booster pump 32 and lifted, and grease is supplied using the exposed lubrication section 142 of the third bearing section 104. The lubrication method of the third bearing section 104 will be described in detail below.

[0055] First, the connection between the housing 46 of the drive unit 31 and the base 111 is released. That is, the worker loosens several bolts 112 to release the connection between the housing body 46a and the base 46b. Next, the connection between the drive unit 31 and the piston 53 is released. That is, the worker enters the inside of the housing 46 through the work opening 108, or inserts a tool into the inside of the housing 46 through the work opening 108 to loosen several bolts 107 to release the connection between the crosshead 45 and the crosshead cover 106.

[0056] Next, the drive unit 31 is lifted relative to the booster pump 32. For example, the drive unit 31 is lifted separately from the booster pump 32 by using a crane device to lift the housing 46. Then, the drive unit 31 is moved using the crane device and placed on a predetermined workbench 200 as shown in Figures 7 and 8. At this point, lubrication is supplied to the third bearing portion 104 of the link portion 43 from below the housing 46. That is, the worker enters the inside of the housing 46 through the work opening 108, or inserts a tool into the inside of the housing 46 through the work opening 108, connects the lubrication gun to the lubrication portion 142, and supplies lubrication.

[0057] As shown in Figures 5 and 6, when grease is supplied from the lubrication gun to the lubrication section 142 at a predetermined pressure, the grease is supplied from the lubrication section 142 to the lubrication groove 143, pushing up both sides of the lubrication groove 143 in the circumferential direction and supplying grease to the top. Then, the grease in the lubrication groove 143 is supplied to a plurality of first lubrication holes 144, and then supplied to the needle bearings 131 and 132 from each of the second lubrication holes 145. Once the lubrication of the third bearing section 104 is complete, the lubrication gun is removed from the lubrication section 142.

[0058] Subsequently, as shown in Figures 5 and 6, the drive unit 31 is lifted and moved using a crane device, and installed on top of the booster pump 32 as shown in Figures 2 and 3. Then, the drive unit 31 and the piston 53 are connected, and the housing 46 of the drive unit 31 is connected to the frame 111.

[0059] [Effects of this embodiment] The compression device according to the first embodiment comprises a drive unit 31 and a boost pump 32 driven by the drive unit 31. The drive unit 31 comprises a housing 46 having a hollow shape with its lower part supported by a frame 111, an eccentric shaft portion 41 that is rotatably supported inside the housing 46 about a first axis O1 that lies horizontally, a drive motor 33 that can rotate the eccentric shaft portion 41, a rotating body 42 that has a second axis O2 that is radially offset from the first axis O1 and is integrally provided on the outer circumference of the eccentric shaft portion 41, and a boost pump that is movably supported inside the housing 46 along the vertical direction. The housing 46 has a crosshead 45 that transmits linear reciprocating power to the piston 53 of the pump 32, a link portion 43 whose upper annular portion 43a is supported so as to be rotatable relative to the outer circumference of the rotating body 42 and whose lower annular portion 43c is rotatably connected to the crosshead 45 around a shaft portion 105 that is aligned horizontally, and a third bearing portion 104 which is positioned between the lower annular portion 43c and the shaft portion 105 and has a lubrication portion 142 at its lower part. The housing 46 is detachably connected to the frame 111, and the crosshead 45 is detachably connected to the piston 53.

[0060] In the compression device according to the first embodiment, the housing 46 is detachably attached to the frame 111, and the crosshead 45 is detachably attached to the piston 53. Therefore, by releasing the connection between the housing 46 and the frame 111, and releasing the connection between the crosshead 45 and the piston 53, the drive unit 31 can be separated from the booster pump 32 and lifted. When the drive unit 31 is lifted, the lubrication section 142 of the third bearing section 104 is exposed, allowing access to the lubrication section 142 and supplying grease to the third bearing section 104, thereby enabling proper lubrication of the drive unit 31. Furthermore, when grease is supplied to the third bearing section 104, it is not necessary to disassemble the entire drive unit 31, and lubrication can be performed while the crank mechanism (link section 43 and crosshead 45, etc.) remains housed in the housing 46, thus shortening the grease supply time. Furthermore, by employing grease lubrication for the third bearing section 104, a lubricating oil storage tank becomes unnecessary, thereby suppressing the increase in size and weight of the drive unit 31.

[0061] The second embodiment of the compression device is the same as the first embodiment, further comprising a housing 46 which includes a housing body 46a that houses an eccentric shaft 41, a rotating body 42, a crosshead 45, and a link 43, and a base 46b which is fixed to the frame 111 and to which the lower part of the housing body 46a is detachably connected. As a result, the connection between the drive unit 31 and the frame 111 can be released by releasing the connection between the housing body 46a and the base 46b.

[0062] The third embodiment of the compression device is the same as the second embodiment, further comprising a working opening 108 in the housing body 46a that is inserted from the outside into the connection between the crosshead 45 and the piston 53. This allows an operator to access the connection between the crosshead 45 and the piston 53 through the working opening 108 and to properly release the connection between the crosshead 45 and the piston 53.

[0063] The fourth embodiment of the compression device is a compression device according to any one of the first to third embodiments, further comprising: a crosshead 45 having a cylindrical portion 45a that houses a lower annular portion 43c and rotatably supports the lower annular portion 43c on the shaft portion 105 by a third bearing portion 104; a piston 53 having its upper end connected to a crosshead cover 106, and the crosshead cover 106 being detachably connected to the lower end of the cylindrical portion 45a. As a result, the connection between the crosshead 45 and the piston 53 can be easily released by removing the crosshead cover 106 from the cylindrical portion 45a of the crosshead 45.

[0064] The fifth embodiment of the compression device is a compression device according to any one of the first to fourth embodiments, further comprising: outer rings 131a, 132a; inner rings 131b, 132b; a plurality of rollers 131c, 132c arranged between the outer rings 131a, 132a and the inner rings 11b, 132b; and dust seals 135, 136 arranged at both axial ends of the outer rings 131a, 132a to cover the gap between the outer rings 131a, 132a and the inner rings 131b, 132b. As a result, the dust seals 135, 136 can suppress the mixing of grease leaking from the second bearing device 103 into the third bearing device 104.

[0065] The sixth embodiment of the compression device is a compression device according to any one of the first to fifth embodiments, further comprising a third bearing section 104 having a plurality of needle bearings 131, 132 arranged along the axial direction, with a ring-shaped outer spacer 133 positioned between the plurality of needle bearings 131, 132, and the outer spacer 133 is provided with an oil supply passage 141 that runs along the circumferential direction and supplies grease supplied to the oil supply section 142 to the needle bearings 131, 132. This allows the grease supplied to the oil supply section 142 to be properly supplied to the needle bearings 131, 132 via the oil supply passage 141.

[0066] The seventh embodiment of the compression device is a compression device according to the sixth embodiment, further comprising: an oil supply passage 141 having an oil supply groove 143 provided circumferentially on the outer circumference of the outer spacer 133; and a first oil supply hole 144 and a second oil supply hole 145 provided radially on the upper part of the outer spacer 133, communicating the oil supply groove 143 with the inside of the needle bearings 131 and 132. As a result, the grease supplied to the oil supply section 142 is carried through the oil supply groove 143, so that grease can be reliably supplied even to locations far from the oil supply section 142. Furthermore, the first oil supply hole 144 and the second oil supply hole 145 allow for the appropriate supply of grease to the upper part of the third bearing section 104, where high pressure is applied and the need for grease supply is particularly high.

[0067] The eighth embodiment of the compression device is a compression device according to any one of the first to seventh embodiments, further comprising a self-aligning bearing as a second bearing portion 103 positioned between the upper annular portion 43a and the rotating body 42, the self-aligning bearing having a lubrication portion 103a at its upper part, and the housing 46 having a lubrication opening 123 at its upper part that allows access to the lubrication portion 103a of the self-aligning bearing. This allows grease to be properly supplied to the second bearing portion 103 from the outside.

[0068] The hydrogen supply system (low-temperature fluid supply system) according to the ninth embodiment comprises a compressor 21 according to any one of the first to eighth embodiments, an evaporator 22 for vaporizing the liquid hydrogen (low-temperature fluid) compressed by the compressor 21, and a dispenser 23 for supplying the hydrogen gas vaporized by the evaporator 22. This allows the compressor 21 to properly supply lubrication to the drive unit 31.

[0069] The lubrication method for the compressor according to the tenth embodiment includes the steps of: releasing the connection between the housing 46 of the drive unit 31 and the frame 111; releasing the connection between the drive unit 31 and the piston 53; lifting the drive unit 31 relative to the booster pump 32; and supplying lubrication to the third bearing portion 104 of the link portion (crank mechanism) 43 from below the housing 46. This allows for proper lubrication of the drive unit 31.

[0070] 10 Hydrogen supply system (low-temperature fluid supply system) 11 Container 12 Vehicle 21 Compressor 22 Evaporator 23 Dispenser 31 Drive unit 32 Booster pump 33 Drive motor 34 Drive mechanism 41 Eccentric shaft 42 Rotating body 43 Link section 43a Upper annular section 43b Connection section 43c Lower annular section 44 Connecting section 45 Crosshead 45a Cylindrical section 45b Ceiling section 45c Bottom section 46 Housing 46a Housing body 46b Base 51 Casing 52 Cylinder 53 Piston 62 Liquid storage chamber 63 Supply pipe 64 Gas discharge pipe 65 Compression chamber 66 Intake valve 67 Discharge valve 68 Discharge piping 101, 102 First bearing section 103 Second bearing section 104 Third bearing section 105 Shaft section 106 Crosshead cover 107 Bolt 108 Working opening 111 Frame 112, 113 Bolts 121, 122 Oil supply hole 123 Oil supply opening 124 Cover section 131, 132 Needle bearing 133 Outer spacer 134 Inner spacer 135, 136 Dust seal 141 Oil supply passage 142 Oil supply section 143 Oil supply groove 144 First oil supply hole 145 Second oil supply hole O1 First axis O2 Second axis O3 Third axis O4 Fourth axis

Claims

1. The system comprises a drive unit and a boost pump driven by the drive unit, wherein the drive unit comprises a housing having a hollow shape with its lower part supported on a frame, an eccentric shaft portion rotatably supported within the housing about a first axis aligned horizontally, a drive motor capable of rotating the eccentric shaft portion, a rotating body integrally provided on the outer circumference of the eccentric shaft portion having a second axis radially offset from the first axis, a crosshead supported within the housing so as to be movable along the vertical direction, thereby transmitting linear reciprocating power to the piston of the boost pump, a link portion whose upper annular portion is supported so as to be rotatably relative to the outer circumference of the rotating body and whose lower annular portion is rotatably connected about an axis portion aligned horizontally to the crosshead, and a bearing portion disposed between the lower annular portion and the axis portion and having a lubrication portion at its lower end, wherein the housing is detachably connected to the frame, and the crosshead is detachably connected to the piston. Compressor.

2. The compression device according to claim 1, wherein the housing comprises a housing body that houses the eccentric shaft portion, the rotating body, the crosshead, and the link portion, and a base that is fixed to the frame and to which the lower part of the housing body is detachably connected.

3. The compression device according to claim 2, wherein the housing body is provided with a working opening that allows insertion from the outside into the connection between the crosshead and the piston.

4. The compression device according to claim 1, wherein the crosshead has a cylindrical portion that houses the lower annular portion and rotatably supports the lower annular portion on the shaft portion by the bearing portion, the upper end of the piston is connected to the crosshead cover, and the crosshead cover is detachably connected to the lower end of the cylindrical portion.

5. The compression device according to claim 1, wherein the bearing portion comprises an outer ring, an inner ring, a plurality of rollers disposed between the outer ring and the inner ring, and dust seals disposed at both axial ends of the outer ring to cover the gap between the outer ring and the inner ring.

6. The compression device according to claim 1, wherein the bearing section has a plurality of needle bearings arranged along the axial direction, a ring-shaped spacer is placed between the plurality of needle bearings, and the spacer is provided with an oil supply passage that runs along the circumferential direction and supplies grease supplied to the oil supply section to the needle bearings.

7. The compression device according to claim 6, wherein the oil supply passage comprises an oil supply groove provided circumferentially on the outer circumference of the spacer and an oil supply hole provided radially on the upper part of the spacer that communicates the oil supply groove with the inside of the needle bearing.

8. The compression device according to claim 1, wherein a self-aligning bearing is disposed between the upper annular portion and the rotating body, the self-aligning bearing has a lubrication portion at its upper part, and the housing has a lubrication opening at its upper part that allows access to the lubrication portion of the self-aligning bearing.

9. A cryogenic fluid supply system comprising: a compression device according to claim 1; an evaporation device for vaporizing the cryogenic fluid compressed by the compression device; and a dispenser for supplying the gas vaporized by the evaporation device.

10. A compression device comprising: a drive unit having a crank mechanism; and a booster pump disposed below the drive unit and having a piston that reciprocates linearly by the crank mechanism, the method comprising: releasing the connection between the housing of the drive unit and a support frame; releasing the connection between the drive unit and the piston; lifting the drive unit relative to the booster pump; and supplying oil to the bearing portion of the crank mechanism from below the housing.

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