JP6370252B2 - Screw compressor - Google Patents

Description

  The present invention relates to a screw compressor provided with a slide valve for capacity adjustment.

  In the screw compressor provided with the capacity adjusting device, the capacity of the screw compressor can be adjusted according to the consumption amount of the discharge gas. The capacity adjusting device includes a slide valve that forms part of the wall surface of the rotor chamber, and a hydraulic cylinder that drives the slide valve in a direction parallel to the axis of the screw rotor. In a screw compressor provided with a capacity adjusting device, the volume of discharged gas is adjusted by driving a slide valve with a hydraulic cylinder and adjusting the length of a screw rotor effective for gas compression. For example, Patent Document 1 is known as a screw compressor that adjusts the volume of discharge gas using a slide valve.

JP 62-41987

  In many cases, the capacity adjusting device is provided at the lower part of the screw compressor because of the relationship of the arrangement position with the suction port, the discharge port and the like in the casing of the compressor. When the hydraulic cylinder is provided in the casing, an oil port for supplying and discharging oil to the hydraulic cylinder may be provided in the lower part of the hydraulic cylinder because of the arrangement position with the rotor shaft and the like located above the capacity adjusting device. Many.

  However, if the oil port is provided in the lower part of the hydraulic cylinder, there is a possibility that the oil port may stay at the uppermost part in the hydraulic cylinder when bubbles are included in the oil. If air bubbles stay in the uppermost part in the hydraulic cylinder, the followability of the slide valve to changes in hydraulic pressure is hindered, and a hunting phenomenon occurs. Such a hunting phenomenon hinders the stable operation of the slide valve and makes it difficult to precisely control the slide valve to adjust the capacity.

  Therefore, the technical problem to be solved by the present invention is to provide a screw compressor that prevents the bubbles from staying at the top of the hydraulic cylinder and improves the stability of the operation of the slide valve. .

  In order to solve the above technical problem, the present invention provides the following screw compressor.

  That is, the screw compressor includes a pair of male and female screw rotors housed in a rotor chamber formed in a casing and a part of the wall surface of the rotor chamber, and advances and retreats in an axial direction parallel to the axis of the screw rotor. A slide valve that adjusts the volume of the slide valve, a piston rod having one end connected to the slide valve, the other end of the piston rod is connected, and the inside of the cylinder chamber is parallel to the axis of the screw rotor. A piston that reciprocally slides in the axial direction, and is disposed on a lower wall portion of the cylinder chamber, provided in a lower wall portion of the casing, and supplies oil to the cylinder chamber, An oil port for discharging oil from the cylinder chamber; and a port position changing member disposed in the cylinder chamber for changing the position of the oil port. Member, to the upper opening which opens to the top and communicating the cylinder chamber, and a lower opening communicating with said oil port, characterized in that it comprises a communication passage that connects the upper opening and the lower opening.

  According to the above configuration, when oil is supplied to the cylinder chamber of the hydraulic cylinder and the piston is operated, bubbles remaining in the uppermost portion of the cylinder chamber are passed through the upper opening, the communication path, and the lower opening of the port position changing member. The oil is discharged together with oil from an oil port provided in the lower wall portion of the cylinder chamber. As a result, the stability of the operation of the slide valve can be improved.

  According to the present invention, it is possible to prevent bubbles from staying at the uppermost part in the hydraulic cylinder and improve the stability of the operation of the slide valve.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows schematic structure of the screw compressor which concerns on 1st Embodiment of this invention. The fragmentary sectional view which shows the hydraulic cylinder and its peripheral part in the screw compressor shown in FIG. The figure explaining the flow of the oil in the port position change member arrange | positioned at the hydraulic cylinder. The fragmentary sectional view which shows the hydraulic cylinder and its peripheral part in the screw compressor which concerns on 2nd Embodiment of this invention. The fragmentary sectional view which shows the hydraulic cylinder and its peripheral part in the screw compressor which concerns on 3rd Embodiment of this invention. The fragmentary sectional view showing the hydraulic cylinder and its peripheral part in the screw compressor concerning a 4th embodiment of the present invention. The fragmentary sectional view which shows the hydraulic cylinder and its peripheral part in the screw compressor which concerns on 5th Embodiment of this invention. The fragmentary sectional view which shows the hydraulic cylinder and its peripheral part in the screw compressor which concerns on 6th Embodiment of this invention. The fragmentary sectional view which shows the hydraulic cylinder and its peripheral part in the screw compressor which concerns on 7th Embodiment of this invention.

(First embodiment)
A screw compressor 1 according to a first embodiment of the present invention will be described with reference to FIGS. First, a schematic configuration of the screw compressor 1 will be described in detail with reference to FIG.

  The screw compressor 1 includes a suction port 16 formed on one side of the casing 10, a discharge port 17 formed on the other side of the casing 10, a rotor chamber 12 formed between the suction port 16 and the discharge port 17, I have. A pair of male and female screw rotors 14 that mesh with each other are accommodated in the rotor chamber 12. The screw rotor 14 includes a rotor shaft 18 at each end on the discharge side and the suction side, and the rotor shaft 18 is supported by a bearing disposed in the bearing space. A drive gear and a timing gear (not shown) are separately attached to each end portion of the rotor shaft 18 on the discharge side (left side in FIG. 1) and the suction side (right side in FIG. 1).

  A rotational driving force of a motor (not shown) is transmitted to one of the screw rotors 14 via a driving gear. The rotational driving force transmitted to one screw rotor 14 is transmitted to the other screw rotor 14 via a timing gear. The pair of male and female screw rotors 14 mesh with each other and rotate, whereby the gas to be compressed is sucked from the suction port 16. The gas sucked from the suction port 16 is compressed to a predetermined pressure, and the compressed gas is discharged from the discharge port 17 as a discharge gas.

  A valve operating space 19 is formed in the casing 10 adjacent to the rotor chamber 12 and below the rotor chamber 12. The valve operation space 19 is a space for accommodating the slide valve 36 and operating the slide valve 36 in an axial direction (hereinafter simply referred to as a lateral direction) parallel to the axis of the screw rotor 14. The valve working space 19 communicates with the rotor chamber 12 through the opening. The slide valve 36 has an opposing upper surface 36A that faces the screw rotor 14 in the vicinity, and the opposing upper surface 36A extends to both sides of the meshing portion of the pair of male and female screw rotors 14, and forms a part of the wall surface of the rotor chamber 12. It is formed to make. A stopper 33 that restricts the movable position of the slide valve 36 in the suction direction is formed on the suction side of the slide valve 36. Further, the upper surface of the stopper 33 forms a part of the wall surface of the rotor chamber 12, similarly to the opposed upper surface 36 </ b> A of the slide valve 36. Although not shown in the drawing, the suction port 16 extends below the rotor shaft 18 and communicates with the suction side space of the valve operating space 19. When the slide valve 36 is moved to the discharge side, a part of the gas compressed in the rotor chamber 12 can be bypassed to the suction port 16. Therefore, the slide valve 36 can adjust the discharge gas volume by moving back and forth in the lateral direction.

  The hydraulic cylinder 30 has a cylinder chamber 20 extending in the lateral direction. In the casing 10, the cylinder chamber 20 is formed adjacent to the suction side of the valve working space 19 and below the suction side of the rotor chamber 12. The suction side of the cylinder chamber 20 is closed in a sealed state by a cylinder sealing member 31. A portion on the suction side of the piston rod 34, a piston 32, and a port position changing member 40 provided on the discharge side of the piston 32 are accommodated in the cylinder chamber 20. The discharge side end of the piston rod 34 is connected to the slide valve 36, and the suction side end of the piston rod 34 is connected to the piston 32 by a piston connector 32A (shown in FIG. 2 and the like). When high-pressure oil is supplied into the cylinder chamber 20, the piston 32 slides in the cylinder chamber 20 in the lateral direction. As described above, the hydraulic cylinder 30 including the piston 32, the piston rod 34, the cylinder chamber 20, and the port position changing member 40 is formed below the casing 10.

  The hydraulic cylinder 30 will be described in detail with reference to FIG. An arrow in the hydraulic cylinder 30 indicates the flow of oil.

  The cylinder chamber 20 of the hydraulic cylinder 30 is a cylindrical space surrounded by the upper wall portion 10A and the lower wall portion 10B. The cylinder chamber 20 is partitioned by a piston 32 into a load side space 20A and an unload side space 20B. A load side oil port 24 communicating with the load side space 20A is provided on the discharge side of the load side space 20A of the lower wall portion 10B. Further, an unload side oil port 26 communicating with the unload side space 20B is provided on the discharge side of the unload side space 20B of the lower wall portion 10B. A seal space having a smaller diameter than the cylinder chamber 20 is formed between the cylinder chamber 20 and the valve operating space 19. A piston seal member 38 is disposed in the seal space, and the piston 32 is slid in the axial direction of the piston 32 in a liquid-tight state.

  A port position changing member 40 (hereinafter simply referred to as a member 40) is disposed at the discharge side end of the load side space 20A. The member 40 has a columnar shape having a thickness in the lateral direction, and has a shaft insertion hole through which the piston 32 is inserted. A gap is provided between the piston 32 and the shaft insertion hole so that they do not contact each other, and the gap is as small as about 0.2 mm, for example. With the size of the gap, the flow passage cross section of the communication passage 49 described later is much larger than the gap, and therefore the oil flow in the load side space 20A is hardly affected.

  The member 40 is non-rotatably mounted in the load-side space 20A by an O-ring 47 as a seal member fitted in an annular groove 46 formed on the outer periphery thereof. That is, the O-ring 47 seals between the outer peripheral surface of the member 40 and the inner peripheral surface of the cylinder chamber 20, and the member 40 is non-rotatably attached to the load side space 20 </ b> A by the frictional force of the O-ring 47. ing. According to the mounting structure, the member 40 is non-rotatable and detachable in the load side space 20A. The attachment structure of the member 40 to the load side space 20A may be configured such that the annular groove 46 is formed on the inner peripheral surface of the load side space 20A and the O-ring 47 is provided on the casing 10 side. .

  The body 41 of the member 40 includes an upper opening 42A, a lower opening 45A, and a communication passage 49 that connects the upper opening 42A and the lower opening 45A. The upper opening 42A is an opening formed in the upper part on the suction side of the body 41 so as to communicate with the uppermost part 21 of the load side space 20A. The lower opening 45 </ b> A is an opening formed in the lower part on the discharge side of the body 41 so as to communicate with the load-side oil port 24.

  The communication path 49 includes an upper horizontal flow path 42, a vertical flow path 43, a lower horizontal flow path 44, and a lower vertical flow path 45 formed in the body 41. The upper horizontal flow path 42 extends from the upper opening 42A to the discharge side in the horizontal direction. The vertical flow path 43 extends downward from the upper horizontal flow path 42 in the vertical direction (hereinafter simply referred to as the vertical direction) with respect to the axis of the screw rotor 14. The lower horizontal flow path 44 extends from the vertical flow path 43 to the discharge side in the horizontal direction, and the lower vertical flow path 45 extends downward from the lower horizontal flow path 44 in the vertical direction and is connected to the lower opening 45A.

  As shown in FIG. 3, for example, the upper lateral flow path 42 is cut out into an upper and lower arc shape having a lower arc in addition to an upper arc at the upper portion of the body 41 when viewed from the suction side in the horizontal direction, that is, the suction side surface. It is a notch. The side shape of the upper lateral flow path 42 is not limited to the shape illustrated in FIG. 3, for example, a half-moon shape with the lower end cut out in the horizontal direction, a semi-oval shape protruding in a U-shape downward, a circular shape, etc. Can be. Note that, in the side surface shape of the upper lateral flow path 42, the opening area of the upper opening 42A increases in the order described above. The larger the opening area of the upper opening 42A, the smaller the pressure loss at the upper opening 42A. The longitudinal flow path 43 is an annular slit cut from the outer periphery of the body 41 toward the center. The lower lateral flow path 44 is a hole that extends from the lateral discharge side to the vertical flow path 43 at a position below the body 41 and above the annular groove 46. The lower vertical flow path 45 is a notch cut into a semi-oval shape that protrudes upward in a U-shape at the lower portion of the body 41 when viewed from the discharge side in the horizontal direction.

  The load-side space 20A is partitioned in a liquid-tight state into a space on the upper horizontal flow path 42 side and a space on the lower vertical flow path 45 side by an O-ring (seal member) 47 fitted in the annular groove 46. . The member 40 is detachably attached to the load side space 20 </ b> A by the O-ring 47 in addition to being non-rotatably attached in the load side space 20 </ b> A. In the load side space 20 </ b> A, the space on the upper lateral flow path 42 side is a space sandwiched between the piston 32 and the member 40, and the volume of the space changes according to the position of the piston 32. In the load side space 20A, the space on the lower vertical flow path 45 side is a minute gap sandwiched between the member 40 and the piston seal member 38, and oil hardly flows through the minute gap.

  In the communication path 49 shown in FIG. 2, the upper horizontal flow path 42 and the vertical flow path 43 are formed as the suction-side flow paths sandwiching the O-ring 47, and the lower vertical flow path 45 is formed as the discharge-side flow path. Has been. The suction-side flow path and the discharge-side flow path communicate with each other via the lower lateral flow path 44. Since the load side space 20 </ b> A is sealed in a liquid-tight state by the member 40, the oil in the load side space 20 </ b> A is guided toward the load side oil port 24 through the communication path 49. Along with the flow of the oil, the bubbles 22 staying in the uppermost portion 21 of the load side space 20 </ b> A are also discharged toward the load side oil port 24 through the communication path 49 of the member 40.

  The load-side oil port 24 and the unload-side oil port 26 are connected to a hydraulic source (not shown) and an oil tank by piping via, for example, a directional control valve (not shown) at a 4-port 3 position. High pressure oil from the hydraulic pressure source is supplied to the load side space 20 </ b> A through the load side oil port 24, or supplied to the unload side space 20 </ b> B through the unload side oil port 26.

  As shown in FIG. 1, when the slide valve 36 is in contact with the stopper 33, the load side oil port 24 communicates with the hydraulic pressure source, and the unload side oil port 26 communicates with the oil tank. In this case, the screw compressor 1 is in a load (full load) operation state, and the entire amount of gas sucked from the suction port 16 is compressed by the screw rotor 14. The compressed gas is discharged to the discharge port 17 as discharge gas. In the load (full load) operation state, capacity adjustment is performed so that the capacity of the discharge gas becomes maximum.

  When the flow path is switched by the direction control valve, the load side oil port 24 communicates with the oil tank and the unload side oil port 26 communicates with the hydraulic pressure source. Then, the high pressure oil is supplied to the unload side space 20B, whereby the piston 32 moves to the discharge side (left side in FIG. 2). Then, the slide valve 36 connected to the piston 32 via the piston rod 34 moves to the discharge side (left side in FIG. 1). As a result, a gap is generated between the slide valve 36 and the stopper 33 (shown in FIG. 1), and the screw compressor 1 enters an unload (partial load or minimum load) operation state, and the discharge gas capacity is reduced. The capacity is adjusted. During the unloading operation, part of the gas sucked into the screw rotor 14 from the suction port 16 is bypassed and returned to the suction port 16 through the suction side space of the valve operating space 19 from the gap. The remaining gas other than the gas returned to the suction port 16 is compressed in the rotor chamber 12, and the compressed gas is discharged from the discharge port 17.

  Then, when the flow path is switched by the direction control valve so that the load side oil port 24 communicates with the hydraulic pressure source and the unload side oil port 26 communicates with the oil tank for capacity adjustment, the piston 32 is moved to the suction side. Move to (right side of FIG. 1). Then, the slide valve 36 connected to the piston 32 via the piston rod 34 moves to the suction side (right side in FIG. 1). As a result, there is no gap between the slide valve 36 and the stopper 33, the entire amount of gas sucked from the suction port 16 is compressed, and the screw compressor 1 enters the load operation state.

  As shown in FIGS. 2 and 3, the bubbles 22 may stay in the upper part of the load side space 20 </ b> A of the hydraulic cylinder 30. Even in such a case, as described below, the bubbles 22 are discharged from the load-side oil port 24 through the communication path 49 together with the oil. That is, when the oil containing the bubbles 22 flows from the load side space 20 </ b> A toward the load side oil port 24, the oil flows in a flow path other than the communication path 49 by the liquid-tight seal structure by the port position changing member 40. This is hindered and is guided to flow through the communication passage 49. As a result, the bubbles 22 staying in the upper part in the load side space 20A are provided in the lower wall portion 10B of the hydraulic cylinder 30 through the upper opening 42A, the communication passage 49, and the lower opening 45A of the port position changing member 40. The oil flows out from the load side oil port 24 together with the oil. Since the air bubbles 22 staying in the upper part of the load side space 20A are discharged together with the oil, the operation stability of the slide valve 36 can be improved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the screw compressor 1 according to the second embodiment, the member 40 of the hydraulic cylinder 30 is detachably fixed to the discharge-side side wall portion 10C of the casing 10 by a member fixing tool 48 such as a hexagon bolt or a screw. Yes. That is, a plurality of screw holes 48A are formed in the body 41, and a plurality of screw holes 48B are formed in the side wall portion 10C on the discharge side of the casing 10 so as to be coaxial with the screw holes 48A. The member 40 is fixed to the discharge-side side wall portion 10 </ b> C of the casing 10 by a member fixing tool 48. The configuration of the member 40 shown in FIG. 4 is basically the same as that shown in FIG. 2, but the member 40 is fixed to the discharge-side side wall portion 10 </ b> C of the casing 10 by the member fixing tool 48. Has been added. Due to the fixing structure, it is possible to reliably prevent positional deviation caused by the member 40 rotating in the cylinder chamber 20 or moving in the axial direction. Therefore, in addition to improving the stability of the operation of the slide valve 36, the bubbles 22 are more reliably discharged through the communication passage 49 together with the oil.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. Note that in the third embodiment, components having the same functions as those in the first embodiment are given the same reference numerals, and redundant descriptions are omitted.

  In the screw compressor 1 according to the third embodiment, a port position changing member 50 (hereinafter simply referred to as a member 50) is also disposed on the suction side of the hydraulic cylinder 30.

  A member 50 is disposed at the suction side end of the unload side space 20B. The member 50 is non-rotatably attached in the unload side space 20B by an O-ring 57 that is fitted into an annular groove 56 formed on the outer periphery thereof. That is, the O-ring 57 seals between the outer peripheral surface of the member 50 and the inner peripheral surface of the cylinder chamber 20, and the member 50 is attached to the unload side space 20 </ b> B so as not to rotate due to the frictional force of the O-ring 57. It has been. The suction side of the unload side space 20 </ b> B is closed in a sealed state by a cylinder sealing member 31.

  The body 51 of the member 50 includes an upper opening 52A, a lower opening 55A, and a communication passage 59 that connects the upper opening 52A and the lower opening 55A. The upper opening 52A is an opening formed in the upper part on the discharge side of the body 51, and communicates with the uppermost part 21 of the unload side space 20B. The lower opening 55 </ b> A is an opening formed in the lower part on the suction side of the body 51 and communicates with the unload side oil port 26.

  The communication path 59 includes an upper horizontal flow path 52, a vertical flow path 53, a lower horizontal flow path 54, and a lower vertical flow path 55 formed in the body 51. The upper lateral flow path 52 extends from the upper opening 52A to the suction side in the lateral direction. The longitudinal channel 53 extends downward from the upper lateral channel 52 in the longitudinal direction. The lower horizontal flow channel 54 extends from the vertical flow channel 53 to the suction side in the horizontal direction, and the lower vertical flow channel 55 extends downward from the lower horizontal flow channel 54 in the vertical direction and is connected to the lower opening 55A.

  Similar to the first embodiment, the upper lateral flow path 52 is, for example, a notch that is cut out in an upper and lower arc shape having a lower arc in addition to an upper arc in the upper portion of the body 51. The side shape of the upper lateral flow path 52 can be, for example, a half-moon shape with the lower end notched in the horizontal direction, a semi-oval shape protruding in a U-shape downward, or a circular shape. The longitudinal flow path 53 is an annular slit cut from the outer periphery of the body 51 toward the center. The lower lateral flow path 54 is a hole extending from the lateral suction side to the vertical flow path 53 at a position below the body 51 and above the annular groove 56. The lower vertical flow channel 55 is, for example, a notch cut into a semi-oval shape that protrudes upward in a U shape at the lower portion of the body 51.

  The unload-side space 20B is partitioned in a liquid-tight state into a space on the upper horizontal flow path 52 side and a space on the lower vertical flow path 55 side by an O-ring (seal member) 57 fitted in the annular groove 56. Yes. The member 50 is detachably attached to the unload side space 20B by the O-ring 57 in addition to being non-rotatably attached in the unload side space 20B. In the unload side space 20 </ b> B, the space on the upper lateral flow path 52 side is a space sandwiched between the piston 32 and the member 50, and the volume of the space changes according to the position of the piston 32.

  In the communication path 59 shown in FIG. 5, an upper lateral flow path 52 and a vertical flow path 53 are formed as discharge-side flow paths sandwiching the O-ring 57, and a lower vertical flow path 55 is formed as a suction-side flow path. Has been. The discharge-side flow channel and the suction-side flow channel communicate with each other via the lower lateral flow channel 54. Since the inside of the unload side space 20 </ b> B is in a liquid-tight state by the member 50, the oil in the unload side space 20 </ b> B is guided toward the unload side oil port 26 through the communication path 59. Along with the flow of the oil, the bubbles 22 staying in the uppermost portion 21 of the unload side space 20B are also discharged toward the unload side oil port 26 through the communication path 59 of the member 50.

  By disposing the member 50 also on the suction side of the hydraulic cylinder 30, even when the bubbles 22 stay in the upper part of the unload side space 20B, the bubbles 22 are unloaded through the communication path 59 together with the oil. It is discharged from the load side oil port 26. Since the air bubbles 22 in the load side space 20A and the unload side space 20B are discharged together with the oil through the member 40 and the member 50, respectively, the operation stability of the slide valve 36 is further improved.

  Note that the member 40 may be disposed only on the suction side of the hydraulic cylinder 30 without the member 40 being disposed on the discharge side of the hydraulic cylinder 30. According to the said structure, the bubble 22 in the unload side space 20B is discharged | emitted through the member 50 with oil, and the stability of operation | movement of the slide valve 36 can be improved.

  Further, in the unload side space 20B shown in FIG. 5, a diameter expansion space is provided so as to increase the diameter on the suction side. By providing the expanded diameter space, a stepped portion is formed in the casing 10. The member 50 is accommodated in the enlarged diameter space in a state where movement to the discharge side is restricted by the stepped portion. Here, the member 50 may be pressed against the step portion by the cylinder sealing member 31. With such a pressing structure, the cylinder sealing member 31 can fix the member 50 in the axial direction with respect to the casing 10. Such a pressing structure can also be used instead of the mounting structure in which the port position changing member 50 cannot be rotated by the seal member 57.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIG. Note that in the fourth embodiment, components having the same functions as those of the components in the first embodiment are given the same reference numerals, and redundant description is omitted.

  In the screw compressor 1 according to the fourth embodiment, the member 40 is attached by fitting at the discharge side end of the load side space 20A.

  As shown in FIG. 6, the member 40 is non-rotatably attached to the load side space 20A by fitting without using the annular groove 46 and the O-ring 47 as shown in FIG. The member 40 includes an upper opening 42A, a lower opening 45A, and a communication passage 49 that connects the upper opening 42A and the lower opening 45A. The communication path 49 includes an upper horizontal flow path 42, a vertical flow path 43, and a lower vertical flow path 45 formed in the body 41.

  The vertical flow path 43 extends downward from the upper horizontal flow path 42 in the vertical direction of the screw rotor 14. The longitudinal flow path 43 is an annular slit cut from the outer periphery of the body 41 toward the center. Since the member 40 does not have the annular groove 46 for the O-ring 47, the depth of cut of the longitudinal flow path 43 can be made shallower than that shown in FIG. The lower vertical flow channel 45 is a notch cut into a semi-oval shape protruding upward in a U shape at the lower part of the body 41 when viewed from the discharge side in the horizontal direction, and extends to the suction side in the horizontal direction. And communicates with the lower portion of the longitudinal channel 43. The lower vertical channel 45 has a lower opening 45 </ b> A at the lowermost part of the lower vertical channel 45. Since the member 40 does not have the annular groove 46, it is not necessary to provide the lower lateral flow path 44 (shown in FIG. 2) for bypassing the annular groove 46. Since the member 40 does not include the lower lateral flow path 44, the communication path 49 in the member 40 can be simplified and the number of processing steps for the communication path 49 can be reduced.

  Therefore, according to the screw compressor 1 of the fourth embodiment, in addition to improving the stability of the operation of the slide valve 36, the communication passage 49 in the member 40 can be simplified and the number of processing steps can be reduced.

(Fifth embodiment)
A fifth embodiment of the present invention will be described with reference to FIG. Note that in the fifth embodiment, components having the same functions as those of the components in the first embodiment are given the same reference numerals, and redundant descriptions are omitted.

  In the screw compressor 1 according to the fifth embodiment, the member 40 is attached by fitting at the discharge side end of the load side space 20 </ b> A, and the communication path 49 extends from the upper horizontal flow path 42 and the vertical flow path 43. It is configured.

  As shown in FIG. 7, the member 40 does not have the annular groove 46 and the O-ring 47 as shown in FIG. 2, and is attached so as not to rotate in the load side space 20A by fitting. The member 40 includes an upper opening 42A, a lower opening 45A, and a communication passage 49 that connects the upper opening 42A and the lower opening 45A. The communication path 49 includes an upper horizontal flow path 42 and a vertical flow path 43 formed in the body 41.

  The vertical flow path 43 extends downward from the upper horizontal flow path 42 in the vertical direction of the screw rotor 14. The longitudinal flow path 43 is an annular slit cut from the outer periphery of the body 41 toward the center. Since the member 40 does not include the annular groove 46 for the O-ring 47, the depth of cut of the vertical flow path 43 can be made shallower than that shown in FIG. The vertical flow path 43 has a lower opening 45 </ b> A at the bottom of the vertical flow path 43. The member 40 does not include the annular groove 46, the lower horizontal flow path 44, or the lower vertical flow path 45 as shown in FIG. The longitudinal flow path 43 is directly connected to the load side oil port 24, and the bubbles 22 are discharged together with the oil through the communication path 49. Since the member 40 does not include the annular groove 46, the lower horizontal flow path 44, and the lower vertical flow path 45, the communication path 49 in the member 40 can be simplified and the number of processing steps of the communication path 49 can be reduced.

  Therefore, according to the screw compressor 1 of the fifth embodiment, in addition to improving the stability of the operation of the slide valve 36, the communication passage 49 in the member 40 can be simplified and the number of processing steps can be reduced.

(Sixth embodiment)
A sixth embodiment of the present invention will be described with reference to FIG. Note that in the sixth embodiment, components having the same functions as those of the components in the fifth embodiment are given the same reference numerals, and redundant descriptions are omitted.

  In the screw compressor 1 according to the sixth embodiment, the member 40 is attached by fitting at the discharge side end portion of the load side space 20A, and the upper opening 42A of the member 40 is formed in the uppermost portion 21 of the body 41. Configured to be located.

  The member 40 shown in FIG. 8 is non-rotatably attached in the load side space 20A by fitting, similarly to the fourth and fifth embodiments, without using the annular groove 46 and the O-ring 47 as shown in FIG. Yes. The member 40 includes an upper opening 42A, a lower opening 45A, and a communication passage 49 that connects the upper opening 42A and the lower opening 45A. The communication path 49 includes a vertical flow path 43.

  On the other hand, a concave portion 28 that is recessed upward is formed in the upper wall portion 10A around the discharge side end portion of the load side space 20A. The concave portion 28 is the uppermost portion 21 in the load side space 20A. The upper opening 42 </ b> A is formed in the upper part of the body 41 so as to face the recess 28 and opens upward in the vertical direction. The recess 28 communicates with the vertical flow path 43 through the upper opening 42A. A lower opening 45 </ b> A is formed in the lower portion of the body 41 so as to face the load-side oil port 24. The longitudinal flow path 43 communicates with the load side oil port 24 through the lower opening 45A. The member 40 of FIG. 8 does not include the annular groove 46, the upper lateral flow path 42, the lower lateral flow path 44, or the lower vertical flow path 45 as shown in FIG. In the configuration of FIG. 8, the load side space 20 </ b> A communicates with the load side oil port 24 through the recess 28 and the longitudinal flow path 43 of the member 40.

  The bubbles 22 staying in the load side space 20A are collected in the concave portion 28 which is the uppermost portion 21. The bubbles 22 collected in the recess 28 are efficiently discharged from the load side oil port 24 through the communication path 59 together with the oil. The arrangement of the recesses 28 makes it easy to collect the bubbles 22, and the bubbles 22 are smoothly discharged together with the oil. Further, since the member 40 does not include the annular groove 46, the upper horizontal flow path 42, the lower horizontal flow path 44, and the lower vertical flow path 45, the communication path 49 in the member 40 is further simplified and the number of processing steps can be further reduced. be able to.

  According to the screw compressor 1 of the sixth embodiment, in addition to improving the stability of the operation of the slide valve 36, the communication passage 49 in the member 40 can be simplified and the number of processing steps can be reduced.

(Seventh embodiment)
In each embodiment shown in FIGS. 2, 4, 5, 6, and 7, the upper opening 42 </ b> A is provided on the side facing the piston 32. Therefore, in the seventh embodiment shown in FIG. 9, the recess 28 is disposed on the uppermost portion 21 of the upper wall portion 10A of the cylinder chamber 20 and the upper opening 42A based on the configuration shown in FIG. The upper opening 42 </ b> A is disposed in the upper part of the body 41 so that the surface of the body 41 faces the recess 28. According to the said structure, it becomes easy to collect the bubble 22 which stays in the cylinder chamber 20 in the recessed part 28, and the bubble 22 collected in the recessed part 28 is efficiently discharged | emitted with oil. Moreover, the said structure is applicable also to the structure shown to FIG.

  Each of the port position changing members 40 and 50 may be formed of one member or a combination of a plurality of members. Further, the mounting structure using the member fixing tool 48 such as a screw described in the second embodiment can be used in place of the sealing members 47 and 57 and the mounting structure by fitting in the third to seventh embodiments. .

As is clear from the above description, the screw compressor according to the present invention is
A pair of male and female screw rotors housed in a rotor chamber formed in the casing;
A slide valve that adjusts the capacity by forming a part of the wall surface of the rotor chamber and moving forward and backward in an axial direction parallel to the axis of the screw rotor;
A piston rod having one end connected to the slide valve, and a piston that is connected to the other end of the piston rod and reciprocally slides in a cylinder chamber in an axial direction parallel to the axis of the screw rotor. A hydraulic cylinder provided at a lower portion of the casing;
An oil port disposed on a lower wall portion of the cylinder chamber for supplying oil to the cylinder chamber and discharging the oil from the cylinder chamber;
A port position changing member disposed in the cylinder chamber and changing the position of the oil port;
The port position changing member includes an upper opening that is open to communicate with the uppermost portion of the cylinder chamber, a lower opening that communicates with the oil port, and a communication path that connects the upper opening and the lower opening.

  According to this configuration, when oil is supplied to the cylinder chamber of the hydraulic cylinder and the piston is operated, bubbles staying at the top of the cylinder chamber are passed through the upper opening, the communication path, and the lower opening of the port position changing member. The oil is discharged together with oil from an oil port provided in the lower wall portion of the cylinder chamber. As a result, the stability of the operation of the slide valve can be improved.

  In addition to the above features, the present invention can have the following features.

  A seal member that seals between an outer peripheral surface of the port position changing member and an inner peripheral surface of the cylinder chamber, and the port position changing member is provided so as not to rotate with respect to the cylinder chamber by the seal member; Yes. According to the mounting structure, the port position changing member is not rotatable in the cylinder chamber and is detachable.

  The port position changing member is screwed to a side wall portion constituting the cylinder chamber. According to this configuration, it is possible to reliably prevent positional deviation caused by the port position changing member rotating in the cylinder chamber or moving in the axial direction.

  The communication path extends in the lateral direction from the upper opening that opens on the side facing the piston, the vertical flow path extends in the vertical direction downward from the upper horizontal flow path, and extends in the horizontal direction from the vertical flow path. A lower lateral flow path, and a lower vertical flow path that extends downward in the vertical direction from the lower lateral flow path and connects to the lower opening. According to the said structure, the bubble which stays in the uppermost part of a cylinder chamber can be discharged | emitted with oil through the communicating path of the port position change member attached so that attachment or detachment was possible.

  When the port position changing member is fitted into the cylinder chamber, the port position changing member is non-rotatably attached to the cylinder chamber. According to this configuration, in addition to improving the stability of the operation of the slide valve, it is possible to achieve simplification of the communication path in the port position changing member and reduction in processing man-hours.

  The cylinder chamber is formed with a recess that is the uppermost portion, and the upper opening is provided so as to face the recess. According to the said structure, it becomes easy to collect a bubble to the recessed part 28, and the bubble staying in a recessed part can be efficiently discharged | emitted with oil.

  The port position changing member is disposed on at least one of the load side and the unload side of the cylinder chamber with the piston interposed therebetween. According to the configuration in which the port position changing member is disposed on both the load side and the unload side of the cylinder chamber, it is possible to further improve the stability of the operation of the slide valve. Further, according to the configuration in which the port position changing member is disposed only on the suction side of the hydraulic cylinder, bubbles in the unload side space are discharged together with oil by the port position changing member, and the stability of the operation of the slide valve is improved. Improvement can be achieved.

DESCRIPTION OF SYMBOLS 1 Screw compressor 10 Casing 10A Upper wall part 10B Lower wall part 10C Side wall part 12 Rotor chamber 14 Screw rotor 16 Suction port 17 Discharge port 18 Rotor shaft 19 Valve operation space 20 Cylinder chamber 20A Load side space 20B Unload side space 21 Maximum Upper part 22 Bubble 24 Load side oil port 26 Unload side oil port 28 Recess 30 Hydraulic cylinder 31 Cylinder sealing member 32 Piston 32A Piston coupling 33 Stopper 34 Piston rod 36 Slide valve 36A Opposing upper surface 38 Piston seal member 40, 50 Port position change Member 41, 51 Body 42, 52 Upper lateral flow path 42A, 52A Upper opening 43, 53 Vertical flow path 44, 54 Lower lateral flow path 45, 55 Lower vertical flow path 45A, 55A Lower opening 46, 56 Annular grooves 47, 57 O-ring (seal member)
48 Member fixture 49 Communication path

Claims (7)

A pair of male and female screw rotors housed in a rotor chamber formed in the casing;
A slide valve that adjusts the capacity by forming a part of the wall surface of the rotor chamber and moving forward and backward in an axial direction parallel to the axis of the screw rotor;
A piston rod having one end connected to the slide valve, and a piston that is connected to the other end of the piston rod and reciprocally slides in a cylinder chamber in an axial direction parallel to the axis of the screw rotor. A hydraulic cylinder provided at a lower portion of the casing;
An oil port disposed on a lower wall portion of the cylinder chamber for supplying oil to the cylinder chamber and discharging the oil from the cylinder chamber;
A port position changing member disposed in the cylinder chamber and changing the position of the oil port;
A screw, wherein the port position changing member includes an upper opening that is open to communicate with the uppermost portion of the cylinder chamber, a lower opening that communicates with the oil port, and a communication passage that connects the upper opening and the lower opening. Compressor. The screw compressor according to claim 1,
A seal member that seals between an outer peripheral surface of the port position changing member and an inner peripheral surface of the cylinder chamber, and the port position changing member is provided so as not to rotate with respect to the cylinder chamber by the seal member; There is a screw compressor. The screw compressor according to claim 1 or 2,
A screw compressor in which the port position changing member is screwed to a side wall portion constituting the cylinder chamber. The screw compressor according to any one of claims 1 to 3,
The communication path extends in the lateral direction from the upper opening that opens on the side facing the piston, the vertical flow path extends in the vertical direction downward from the upper horizontal flow path, and extends in the horizontal direction from the vertical flow path. A screw compressor comprising: a lower lateral flow path; and a lower vertical flow path extending downward in the vertical direction from the lower lateral flow path and connected to the lower opening. The screw compressor according to claim 1,
A screw compressor in which the port position changing member is provided so as not to rotate with respect to the cylinder chamber by fitting the port position changing member into the cylinder chamber. The screw compressor according to any one of claims 1 to 5,
A screw compressor, wherein the cylinder chamber is formed with a recess as the uppermost portion, and the upper opening is provided so as to face the recess. The screw compressor according to any one of claims 1 to 6,
A screw compressor, wherein the port position changing member is disposed on at least one of a load side and an unload side of the cylinder chamber with the piston interposed therebetween.

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