US20200003211A1 - Screw compressor - Google Patents

Screw compressor Download PDF

Info

Publication number
US20200003211A1
US20200003211A1 US16/484,796 US201816484796A US2020003211A1 US 20200003211 A1 US20200003211 A1 US 20200003211A1 US 201816484796 A US201816484796 A US 201816484796A US 2020003211 A1 US2020003211 A1 US 2020003211A1
Authority
US
United States
Prior art keywords
rotor
oil supply
gate
lubricant
screw
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US16/484,796
Other languages
English (en)
Inventor
Harunori Miyamura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daikin Industries Ltd
Original Assignee
Daikin Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daikin Industries Ltd filed Critical Daikin Industries Ltd
Assigned to DAIKIN INDUSTRIES, LTD. reassignment DAIKIN INDUSTRIES, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MIYAMURA, HARUNORI
Publication of US20200003211A1 publication Critical patent/US20200003211A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/48—Rotary-piston pumps with non-parallel axes of movement of co-operating members
    • F04C18/50—Rotary-piston pumps with non-parallel axes of movement of co-operating members the axes being arranged at an angle of 90 degrees
    • F04C18/52—Rotary-piston pumps with non-parallel axes of movement of co-operating members the axes being arranged at an angle of 90 degrees of intermeshing engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/80—Other components
    • F04C2240/809—Lubricant sump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/02—Lubrication; Lubricant separation

Definitions

  • the present invention relates to a screw compressor.
  • a screw compressor having a first rotor comprised of a screw rotor provided with helical grooves, and second rotors which mesh with the first rotor and rotate together with the first rotor has been used (see Patent document 1 below).
  • Patent Document 1 discloses a single-screw compressor including a screw rotor as a first rotor which is rotatably housed in a cylindrical wall, and gate rotors as second rotors which are arranged outside the cylindrical wall. Some of gates of each gate rotor enter the internal space of the cylindrical wall through an opening formed therein to mesh with the screw rotor, so that the gate rotors rotate together with the screw rotor.
  • the cylindrical wall, the screw rotor, and the gates meshing with the screw rotor define a compression chamber in the helical grooves.
  • the screw rotor is driven by an electric motor to rotate, the gates meshing with the screw rotor are pushed to rotate the two gate rotors.
  • the capacity of the compression chamber decreases to compress the fluid.
  • a lubricant is injected toward the screw rotor from an oil supply port formed at a predetermined position of the cylindrical wall to supply the lubricant between sliding surfaces of two members, such as the screw rotor and the gate, or the screw rotor and the cylindrical wall, thereby lubricating the sliding surfaces, or sealing a minute gap, if any, formed between the two members when they do not slide.
  • This configuration keeps the sliding surfaces of the screw compressor from wearing or seizing, and blocks a high pressure fluid from leaking from the compression chamber defined by the cylindrical wall, the screw rotor, and the gate.
  • Patent Document 1 Japanese Published Patent Application No. 2009-197794
  • the screw compressor described above requires the injection of a large amount of lubricant in order to supply the lubricant to the sliding surfaces with reliability.
  • a first aspect of the present disclosure is directed to a screw compressor comprising: a first rotor ( 40 ) provided with a helical groove ( 41 ); a second rotor ( 50 ) which meshes with the first rotor ( 40 ) and rotates together with the first rotor ( 40 ); a rotor casing ( 30 ) which covers at least an outer periphery of the first rotor ( 40 ), and defines a compression chamber ( 23 ) in the helical groove ( 41 ) together with the first rotor ( 40 ) and the second rotor ( 50 ), wherein a fluid is compressed in the compression chamber ( 23 ), and at least one of the first rotor ( 40 ) or the second rotor ( 50 ) is provided with an oil supply passage ( 5 ) which is connected to an oil supply port ( 4 ) opened at a sliding surface ( 3 ) of the rotor ( 40 , 50 ) to supply a lubricant to the sliding surface ( 3 ).
  • the oil supply passage ( 5 ) is formed in at least one of the rotors ( 40 , 50 ), i.e., the first rotor ( 40 ) and the second rotor ( 50 ) which mesh with each other and rotate together, and the oil supply passage ( 5 ) is connected to the oil supply port ( 4 ) opened at the sliding surface ( 3 ) of the rotor ( 40 , 50 ) in which the oil supply passage ( 5 ) is formed.
  • the lubricant in the oil supply passage ( 5 ) flows from the oil supply port ( 4 ) to the sliding surface ( 3 ) to lubricate the sliding surface ( 3 ), or seal a gap, if any, between the sliding surface ( 3 ) and its counterpart sliding surface.
  • the oil supply port ( 4 ) is opened at the sliding surface ( 3 ) of the rotor ( 40 , 50 ) that rotates, from which the lubricant is allowed to flow to the sliding surface ( 3 ). Therefore, the lubricant flowing from the oil supply port ( 4 ) is rapidly spread over the rotating rotor ( 40 , 50 ), and is rapidly supplied to the sliding surface ( 3 ) other than the sliding surface ( 3 ) at which the oil supply port ( 4 ) is formed.
  • the lubricant supplied to one of the rotors ( 40 , 50 ) provided with the oil supply passage ( 5 ) is rapidly spread to the other rotor ( 50 , 40 ).
  • the lubricant is quickly supplied to the sliding surface ( 3 ) of the other rotor ( 50 , 40 ).
  • a second aspect of the present disclosure is an embodiment of the first aspect.
  • a switching mechanism ( 6 ) switches the oil supply passage ( 5 ) between a supply state in which the lubricant is supplied to the sliding surface ( 3 ) and a non-supply state in which no lubricant is supplied to the sliding surface ( 3 ).
  • the oil supply passage ( 5 ) can be switched between the supply state in which the lubricant is supplied from the oil supply passage ( 5 ) to the sliding surface ( 3 ), and the non-supply state in which no lubricant is supplied from the oil supply passage ( 5 ) to the sliding surface ( 3 ).
  • a third aspect of the present disclosure is an embodiment of the second aspect.
  • the switching mechanism ( 6 ) is configured to switch the oil supply passage ( 5 ) to the supply state by causing an oil supply source ( 94 c . 95 c ) for supplying the lubricant to the oil supply passage ( 5 ) to communicate with the oil supply passage ( 5 ) when a rotational angle position of the rotor ( 40 , 50 ) provided with the oil supply passage ( 5 ) is in a predetermined angular range, and to switch the oil supply passage ( 5 ) to the non-supply state by blocking the oil supply source ( 94 c , 95 c ) from the oil supply passage ( 5 ) when the rotational angle position of the rotor ( 40 , 50 ) is out of the predetermined angular range.
  • the oil supply source ( 94 c . 95 c ) communicates with the oil supply passage ( 5 ), and the oil supply passage ( 5 ) is switched to the supply state.
  • the oil supply source ( 94 c , 95 c ) and the oil supply passage ( 5 ) are blocked from each other, and the oil supply passage ( 5 ) is switched to the non-supply state.
  • a fourth aspect of the present disclosure is an embodiment of any one of the first to third aspects.
  • the first rotor ( 40 ) is a screw rotor ( 40 ) rotatably housed in a cylindrical wall ( 30 ) constituting the rotor casing ( 30 )
  • the second rotor ( 50 ) is a gear-shaped gate rotor ( 50 ) having a plurality of flat gates ( 51 ) and arranged outside the cylindrical wall ( 30 ), some of the gates ( 51 ) entering a space inside the cylindrical wall ( 30 ) via an opening ( 39 ) formed in the cylindrical wall ( 30 ) and meshing with the screw rotor ( 40 ) so that the gate rotor ( 50 ) rotates together with the screw rotor ( 40 ),
  • the oil supply passage ( 5 ) is formed in at least one of the gates ( 51 ) of the gate rotor ( 50 ), and the oil supply port ( 4 ) is a lateral oil supply port ( 63 b ) opened at a side surface (
  • the screw compressor ( 1 ) is configured as a single-screw compressor ( 1 ), and the gate rotor ( 50 ) which meshes with the screw rotor ( 40 ) rotates as the screw rotor ( 40 ) rotates.
  • the position of the gate ( 51 ) in the helical groove ( 41 ) of the screw rotor ( 40 ) changes, the capacity of the compression chamber ( 23 ) gradually decreases, and the fluid is compressed.
  • the lubricant in the oil supply passage ( 5 ) formed in the gate ( 51 ) of the gate rotor ( 50 ) flows from the lateral oil supply port ( 63 b ) opened at the side surface ( 51 a , 51 b ) of the gate ( 51 ) sliding on the screw rotor ( 40 ).
  • the lubricant is supplied between the side surface ( 51 a , 51 b ) of the gate ( 51 ) and the screw rotor ( 40 ), thereby lubricating these sliding surfaces ( 3 ), or sealing a gap, if any, between these sliding surfaces ( 3 ).
  • the lubricant supplied between the side surface ( 51 a , 51 b ) of the gate ( 51 ) and the screw rotor ( 40 ) adheres to the screw rotor ( 40 ), and is spread toward the outer periphery of the screw rotor ( 40 ) by the effect of a centrifugal force generated by the rotation of the screw rotor ( 40 ).
  • the lubricant is supplied to a gap between the screw rotor ( 40 ) and the cylindrical wall ( 30 ) to seal the gap.
  • a fifth aspect of the present disclosure is an embodiment of the fourth aspect.
  • the lateral oil supply port ( 63 b ) is opened at least at one of side surfaces ( 51 b ), including the side surface ( 51 a , 51 b ), on a rear side in a direction of rotation of the at least one gate ( 51 ).
  • the side surface ( 51 b ) on the rear side in the rotation direction of the gate ( 51 ) is the sliding surface which reliably slides on the screw rotor ( 40 ) and is pushed by the screw rotor ( 40 ), and therefore, is probably worn through the sliding movement.
  • the lubricant is directly supplied to the rear side surface ( 51 b ) of the gate ( 51 ) in the rotation direction from the oil supply passage ( 5 ). This makes it possible to reliably supply the lubricant to the gap between the rear side surface ( 51 b ) of the gate ( 51 ) in the rotation direction, which is probably worn through the sliding movement, and the lateral faces of the helical groove ( 41 ) of the screw rotor ( 40 ), thereby lubricating the sliding surfaces ( 3 ).
  • a sixth aspect of the present disclosure is an embodiment of the fourth or fifth aspect.
  • the oil supply passage ( 5 ) is connected to a front oil supply port ( 63 c ) opened at a front surface ( 51 c ) of the at least one gate ( 51 ) facing the compression chamber ( 23 ).
  • the rotation of the gate rotor ( 50 ) causes the gate ( 51 ) to come in and out of the space inside the cylindrical wall ( 30 ) via the opening ( 39 ).
  • a gap is formed between the front surface ( 51 c ) of the gate ( 51 ) and the cylindrical wall ( 30 ), but the front surface ( 51 c ) of the gate ( 51 ) may slide on the cylindrical wall ( 30 ) when the gate rotor ( 50 ) thermally expands.
  • the lubricant may possibly leak from the high pressure compression chamber ( 23 ) through the gap to a low-pressure space outside the cylindrical wall ( 30 ) in which the gate rotor ( 50 ) is disposed. Thus, the gap needs to be sealed.
  • the oil supply passage ( 5 ) is also connected to the front oil supply port ( 63 c ) opened at the front surface ( 51 c ) of the gate ( 51 ). Therefore, in the gate ( 51 ) of the gate rotor ( 50 ), the lubricant in the oil supply passage ( 5 ) is supplied not only to the side surface ( 51 a , 51 b ) that slide on the screw rotor ( 40 ) but also to the front surface ( 51 c ) that faces the compression chamber ( 23 ).
  • the lubricant is supplied between the front surface ( 51 c ) of the gate ( 51 ) and the cylindrical wall ( 30 ), thereby lubricating the front surface ( 51 c ) and the cylindrical wall ( 30 ), or sealing a gap, if any, formed between the front surface ( 51 c ) and the cylindrical wall ( 30 ).
  • the lateral oil supply port ( 63 b ) includes at least one lateral oil supply port ( 63 b ) formed at a position closer to a base end of the at least one gate ( 51 ) than a center, of the at least one gate ( 51 ), in a radial direction of the gate rotor ( 50 ).
  • the lubricant in the oil supply passage ( 5 ) is supplied to a portion of the side surface ( 51 a , 51 b ) of the gate ( 51 ) sliding on the screw rotor ( 40 ) closer to the base end than the center thereof in the radial direction.
  • the lubricant supplied to the portion of the side surface ( 51 a , 51 b ) of the gate ( 51 ) closer to the base end is spread toward the distal end of the gate ( 51 ) by the effect of the centrifugal force generated by the rotation of the gate rotor ( 50 ).
  • the screw compressor ( 1 ) further comprises a support member ( 55 ) supporting the gate rotor ( 50 ) from a rear side opposite to the compression 51 chamber ( 23 ), wherein an oil sump ( 62 ) to which the lubricant is supplied is formed between the support member ( 55 ) and a coupling portion ( 52 ) of the gate rotor ( 50 ) coupling base ends of the plurality of gates ( 51 ), and the oil supply passage ( 5 ) extends in a radial direction of the gate rotor ( 50 ) of the at least one gate ( 51 ), and has a base end connected to the oil sump ( 62 ).
  • the oil supply passage ( 5 ) extends radially outward from the oil sump ( 62 ) closer to the base end than the gate ( 51 ).
  • the gate rotor ( 50 ) rotates to generate the centrifugal force, which causes the lubricant to enter and flow radially outward through the oil supply passage ( 5 ) extending from the oil sump ( 62 ) along the gate ( 51 ), and flow from the lateral oil supply port ( 63 b ) to be supplied between the side surface ( 51 a , 51 b ) of the gate ( 51 ) and the screw rotor ( 40 ).
  • a ninth aspect of the present disclosure is an embodiment of any one of the first to third aspects.
  • the oil supply passage ( 5 ) is formed in the first rotor ( 40 ), and the oil supply port ( 4 ) is an in-groove oil supply port ( 66 d ) opened at an inner surface ( 42 ) of the helical groove ( 41 ) serving as the sliding surface ( 3 ) of the first rotor ( 40 ) sliding on the second rotor ( 50 ).
  • the oil supply passage ( 5 ) is formed in the first rotor ( 40 ), and connected to the in-groove oil supply port ( 66 d ) opened at the inner surface ( 42 ) of the helical groove ( 41 ) of the first rotor ( 40 ).
  • the lubricant in the oil supply passage ( 5 ) flows from the in-groove oil supply port ( 66 d ) to the inner surface ( 42 ) of the helical groove ( 41 ) which slides on the second rotor ( 50 ), thereby lubricating the inner surface ( 42 ) of the helical groove, or sealing a gap, if any, between the inner surface ( 42 ) and the second rotor ( 50 ) sliding on the inner surface ( 42 ).
  • the lubricant is directly supplied to the inner surface ( 42 ) of the helical groove serving as the sliding surface ( 3 ) from the in-groove oil supply port ( 66 d ) opened at the inner surface ( 42 ) of 10 o the helical groove of the first rotor ( 40 ).
  • the oil supply port ( 4 ) is opened at the inner surface ( 42 ) of the helical groove of the first rotor ( 40 ) that rotates, from which the lubricant is allowed to flow to the inner surface ( 42 ). Therefore, the lubricant which has flowed from the in-groove oil supply port ( 66 d ) is rapidly spread over the rotating first rotor ( 40 ) by the effect of the centrifugal force, and thus, the lubricant is quickly supplied to the sliding surfaces ( 3 ) other than the inner surface ( 42 ).
  • the lubricant supplied to the inner surface ( 42 ) of the helical groove of the first rotor ( 40 ) adheres to the second rotor ( 50 ) which meshes with and rotates with the first rotor ( 40 ), and is rapidly spread over the second rotor ( 50 ) by the effect of the centrifugal force.
  • the lubricant is quickly supplied to the sliding surface ( 3 ) of the second rotor ( 50 ).
  • a tenth aspect of the present disclosure is an embodiment of any one of the first to third aspects.
  • the oil supply passage ( 5 ) is formed in the first rotor ( 40 ), and the oil supply port ( 4 ) is an outer peripheral oil supply port ( 66 c ) opened at an outer peripheral surface ( 43 ) of the first rotor ( 40 ) serving as the sliding surface ( 3 ) of the first rotor ( 40 ) sliding on the rotor casing ( 30 ).
  • the outer peripheral surface ( 43 ) of the first rotor ( 40 ) provided with the helical grooves ( 41 ) slides on the inner surface of the rotor casing ( 30 ) covering the outer periphery of the first rotor ( 40 ).
  • lubrication is required to keep the outer peripheral surface ( 43 ) of the first rotor ( 40 ) and the inner surface of the rotor casing ( 30 ) from seizing.
  • the gap needs to be sealed so that the high pressure fluid does not leak to the low pressure side.
  • the oil supply passage ( 5 ) is formed in the first rotor ( 40 ), and connected to the outer peripheral oil supply port ( 66 c ) opened at the outer peripheral surface ( 43 ) of the first rotor ( 40 ) that slides on the rotor casing ( 30 ).
  • the lubricant in the oil supply passage ( 5 ) flows from the outer peripheral oil supply port ( 66 c ) to the outer peripheral surface ( 43 ) of the first rotor ( 40 ) that slides on the inner surface of the rotor casing ( 30 ), thereby lubricating the outer peripheral surface ( 43 ), or sealing a gap, if any, between the outer peripheral surface ( 43 ) and the inner surface of the rotor casing ( 30 ).
  • the oil supply port ( 4 ) is opened at the outer peripheral surface ( 43 ) of the first rotor ( 40 ) that rotates, from which the lubricant is allowed to flow to the outer peripheral surface ( 43 ). Therefore, the lubricant that has flowed from the outer peripheral oil supply port ( 66 c ) is rapidly spread over the rotating first rotor ( 40 ), and is quickly supplied to the sliding surfaces ( 3 ) other than the outer peripheral surface ( 43 ) at which the outer peripheral oil supply port ( 66 c ) is formed.
  • the lubricant supplied to the first rotor ( 40 ) is rapidly spread to the second rotor ( 50 ).
  • the lubricant can be quickly supplied to the sliding surface ( 3 ) of the second rotor ( 50 ).
  • the first rotor ( 40 ) has an oil sump ( 44 ) to which the lubricant is supplied, the oil sump ( 44 ) being formed at a position closer to a rotation axis of the first rotor ( 40 ) than a bottom face ( 42 c ) of the helical groove ( 41 ), and the oil supply passage ( 5 ) extends from the oil sump ( 44 ) toward an outer periphery of the first rotor ( 40 ).
  • the oil supply passage ( 5 ) extends from the oil sump ( 44 ) closer to the rotation axis than the bottom face ( 42 c ) of the helical groove ( 41 ) of the first rotor ( 40 ) toward the outer periphery of the first rotor ( 40 ).
  • the first rotor ( 40 ) rotates to generate the centrifugal force, which causes the lubricant to enter the oil supply passage ( 5 ) from the oil sump ( 44 ), flow toward the outer periphery of the first rotor ( 40 ), and flow from the oil supply port ( 4 ) to be supplied to the sliding surface ( 3 ) of the first rotor ( 40 ).
  • the oil supply passage ( 5 ) is formed in at least one of the rotors ( 40 , 50 ), i.e., the first rotor ( 40 ) and the second rotor ( 50 ) which mesh with each other and rotate together, and the oil supply passage ( 5 ) is connected to the oil supply port ( 4 ) opened at the sliding surface ( 3 ) of the rotor ( 40 , 50 ) so that the lubricant is directly supplied from the oil supply port ( 4 ) to the sliding surface ( 3 ).
  • the oil supply port ( 4 ) is opened at the sliding surface ( 3 ) of the rotor ( 40 , 50 ) that rotates, from which the lubricant is allowed to flow to the sliding surface ( 3 ). Therefore, the lubricant that has flowed from the oil supply port ( 4 ) is rapidly spread over the rotating rotor ( 40 , 50 ), and can be quickly supplied to the sliding surface ( 3 ) other than the sliding surface ( 3 ) at which the oil supply port ( 4 ) is formed.
  • the lubricant supplied to one of the rotors ( 40 , 50 ) in which the oil supply passage ( 5 ) is formed is rapidly spread to the other rotor ( 50 , 40 ).
  • the lubricant can be quickly supplied to the sliding surface ( 3 ) of the other rotor ( 50 , 40 ).
  • the efficiency of the compressor is not lowered because it is unnecessary to increase the power for the transport of the lubricant and the power for the rotation of the first and second rotors ( 40 , 50 ), unlike in the conventional configuration in which a large amount of lubricant is supplied.
  • the sliding surfaces ( 3 ) of the first rotor ( 40 ) and the second rotor ( 50 ) can be kept from seizing, and the high pressure fluid can be blocked from leaking from the compression chamber, even if the supply amount of the lubricant is reduced. Therefore, according to the first aspect of the present disclosure, the supply amount of the lubricant can be reduced without lowering the reliability of the screw compressor ( 1 ), which can improve the compressor efficiency.
  • the oil supply passage ( 5 ) can be switched between the supply state in which the lubricant is supplied from the oil supply passage ( 5 ) to the sliding surface ( 3 ), and the non-supply state in which no lubricant is supplied from the oil supply passage ( 5 ) to the sliding surface ( 3 ).
  • the oil supply passage can be switched to the non-supply state to stop the supply of the lubricant to the sliding surface ( 3 ) when the sliding surface ( 3 ) does not slide and requires no lubrication. Therefore, according to the second aspect of the present disclosure, the lubricant can be reliably supplied to the sliding surface ( 3 ) of the rotor ( 40 , 50 ), while reducing the amount of the lubricant supplied.
  • the oil supply source ( 94 c , 95 c ) communicates with the oil supply passage ( 5 ), and the oil supply passage ( 5 ) is switched to the supply state.
  • the oil supply source ( 94 c , 95 c ) and the oil supply passage ( 5 ) are blocked from each other, and the oil supply passage ( 5 ) is switched to the non-supply state.
  • Such a simple configuration of the third aspect of the present disclosure makes it possible to automatically switch the oil supply passage ( 5 ) between the supply state and the non-supply state while the rotor ( 40 , 50 ) provided with the oil supply passage ( 5 ) makes a single rotation.
  • each of the gates ( 51 ) of the gate rotor ( 50 ) is provided with the oil supply passage ( 5 ) which directly supplies the lubricant to the side surface ( 51 a , 51 b ) which slide on the screw rotor ( 51 ) and need to be lubricated and sealed by the lubricant.
  • the lubricant can be reliably supplied to the sliding surfaces ( 3 ) of the gate ( 51 ) and the screw rotor ( 40 ) in a smaller amount, thereby lubricating the sliding surfaces ( 3 ), or sealing a gap, if any, between the sliding surfaces ( 3 ).
  • the lubricant supplied in this manner to the sliding surfaces ( 3 ) of the screw rotor ( 40 ) and the gate ( 51 ) also adheres to the screw rotor ( 40 ), and is spread toward the outer periphery of the screw rotor ( 40 ) by the effect of the centrifugal force generated by the rotation of the screw rotor ( 40 ).
  • the lubricant can also be supplied to a gap between the screw rotor ( 40 ) and the cylindrical wall ( 30 ) to seal the gap.
  • the efficiency of the compressor is not lowered because it is unnecessary to increase the power for the transport of the lubricant and the power for the rotation of the screw rotor ( 40 ), unlike in the conventional configuration in which a large amount of lubricant is supplied.
  • Directly supplying the lubricant in a small amount to the sliding surfaces ( 3 ) of the gate ( 51 ) and the screw rotor ( 40 ) makes it possible to lubricate the gate ( 51 ) and the screw rotor ( 40 ), and the screw rotor ( 40 ) and the cylindrical wall ( 30 ), and to seal the gap between the gate ( 51 ) and the screw rotor ( 40 ), and the gap between screw rotor ( 40 ) and the cylindrical wall ( 30 ), if any.
  • the gate rotor ( 50 ) and the screw rotor ( 40 ) can be kept from seizing, and the high pressure fluid can be blocked from leaking from the compression chamber, even if the supply amount of the lubricant is reduced. Therefore, according to the fourth aspect of the present disclosure, the supply amount of the lubricant can be reduced without lowering the reliability of the single-screw compressor ( 1 ), which can improve the compressor efficiency.
  • the lateral oil supply port ( 63 b ) of the oil supply passage ( 5 ) is opened at least at the side surface ( 51 b ) of the gate ( 51 ) on the rear side in the direction of rotation of the gate ( 51 ).
  • the rear side surface ( 51 b ) in the rotation direction of the gate ( 51 ) is the sliding surface ( 3 ) which reliably slides on the screw rotor ( 40 ) and is pressed by the screw rotor ( 40 ), and therefore, is probably worn through the sliding movement.
  • the lateral oil supply port ( 63 b ) opened at the rear side surface ( 51 b ) causes the lubricant to be reliably supplied between the rear side surface ( 51 b ) and the lateral face of the helical groove ( 41 ). This can protect the gate ( 51 ) and the screw rotor ( 40 ) from the sliding wear.
  • the oil supply passage ( 5 ) of the gate ( 51 ) is connected to not only the lateral oil supply port ( 63 b ) which is opened at the side surface ( 51 a , 51 b ) that slide on the screw rotor ( 40 ) of the gate ( 51 ), but also the front oil supply port ( 63 c ) which is opened at the front surface ( 51 c ) of the gate ( 51 ).
  • the lubricant in the oil supply passage ( 5 ) can be supplied not only to the side surface ( 51 a , 51 b ) that slide on the screw rotor ( 40 ), but also to the front surface ( 51 c ) that faces the compression chamber ( 23 ).
  • the lubricant is supplied between the front surface ( 51 c ) of the gate ( 51 ) and the cylindrical wall ( 30 ) to lubricate the front surface ( 51 c ) and the cylindrical wall ( 30 ), or seal a gap, if any, between the front surface ( 51 c ) and the cylindrical wall ( 30 ).
  • the lateral oil supply port ( 63 b ) opened at the side surface ( 51 a , 51 b ) of the gate ( 51 ) which slides on the screw rotor ( 40 ) includes at least one lateral oil supply port ( 63 b ) formed at a position closer to the base end of the gate ( 51 ) than the center thereof in the radial direction of the gate ( 51 ).
  • the at least one lateral oil supply port ( 63 b ) formed at the position closer to the base end of the gate ( 51 ) than the center thereof in the radial direction makes it possible to supply the lubricant to the base end of the side surface ( 51 a , 51 b ) of the gate ( 51 ), and to easily spread the lubricant toward the distal end of the side surface ( 51 a , 51 b ) of the gate ( 51 ) by utilizing the centrifugal force.
  • This configuration can minimize the number of the lateral oil supply ports ( 63 b ), and can further reduce the supply amount of the lubricant.
  • the oil sump ( 62 ) is formed between the support member ( 55 ) supporting the gate rotor ( 50 ) and the coupling portion ( 52 ) of the gate rotor ( 50 ) coupling the base ends of the gates ( 51 ), and an end of the oil supply passage ( 5 ) toward the base ends of the gates ( 51 ) is connected to the oil sump ( 62 ). That is, the oil supply passage ( 5 ) extends radially outward from the oil sump ( 62 ) along the corresponding gate ( 51 ).
  • the gate rotor ( 50 ) rotates to generate the centrifugal force, which causes the lubricant in the oil sump ( 62 ) to enter and flow radially outward through the oil supply passage ( 5 ) in the gate ( 51 ), and flows from the lateral oil supply port ( 63 b ) to be supplied between the side surface ( 51 a , 51 b ) of the gate ( 51 ) and the screw rotor ( 40 ). That is, this simple configuration can supply the lubricant between the side surface ( 51 a , 51 b ) of the gate ( 51 ) and the screw rotor ( 40 ) by utilizing the centrifugal force generated by the rotation of the gate rotor ( 50 ).
  • the oil supply passage ( 5 ) is formed in the first rotor ( 40 ), and connected to the in-groove oil supply port ( 66 d ) opened at the inner surface ( 42 ) of the helical groove ( 41 ) of the first rotor ( 40 ), so that the lubricant is directly supplied from the in-groove oil supply port ( 66 d ) to the inner surface ( 42 ) of the helical groove, which is the sliding surface ( 3 ) which slides on the second rotor ( 50 ).
  • the lubricant can be reliably supplied in a smaller amount to the inner surface ( 42 ) of the helical groove of the first rotor ( 40 ).
  • the in-groove oil supply port ( 66 d ) is opened at the inner surface ( 42 ) of the helical groove of the first rotor ( 40 ) that rotates, from which the lubricant is allowed to flow to the inner surface ( 42 ).
  • the lubricant that has flowed from the in-groove oil supply port ( 66 d ) is rapidly spread over the rotating first rotor ( 40 ), and the lubricant can also be quickly supplied to the sliding surface ( 3 ) other than the inner surface ( 42 ).
  • the lubricant supplied to the inner surface ( 42 ) of the helical groove of the first rotor ( 40 ) also adheres to the second rotor ( 50 ) which meshes with and rotates with the first rotor ( 40 ), and is rapidly spread over the second rotor ( 50 ) by the effect of the centrifugal force.
  • the lubricant can be quickly supplied to the sliding surface ( 3 ) of the second rotor ( 50 ).
  • the oil supply passage ( 5 ) is formed in the first rotor ( 40 ), and connected to the outer peripheral oil supply port ( 66 c ) formed at the outer peripheral surface ( 43 ) which slides on the rotor casing ( 30 ) of the first rotor ( 40 ), so that the lubricant is directly supplied from the outer peripheral oil supply port ( 66 c ) to the outer peripheral surface ( 43 ) which is the sliding surface ( 3 ).
  • This makes it possible to reliably supply the lubricant to the outer peripheral surface ( 43 ) of the first rotor ( 40 ) which slides on the inner surface of the rotor casing ( 30 ).
  • the oil supply port ( 4 ) is opened at the outer peripheral surface ( 43 ) of the first rotor ( 40 ) that rotates, from which the lubricant is allowed to flow to the outer peripheral surface ( 43 ). Therefore, the lubricant that has flowed from the outer peripheral oil supply port ( 66 c ) is rapidly spread over the rotating first rotor ( 40 ), and is quickly supplied to the sliding surface ( 3 ) other than the outer peripheral surface ( 43 ) of the first rotor ( 40 ) at which the outer peripheral oil supply port ( 66 c ) is formed.
  • the lubricant supplied to the first rotor ( 40 ) is rapidly spread to the second rotor ( 50 ).
  • the lubricant can be quickly supplied to the sliding surface ( 3 ) of the second rotor ( 50 ).
  • the oil sump ( 44 ) is formed at a position closer to the rotation axis of the first rotor ( 40 ) than the bottom face ( 42 c ) of the helical groove ( 41 ), and a base end of the oil supply passage ( 5 ) is connected to the oil sump ( 44 ). That is, the oil supply passage ( 5 ) extends from the oil sump ( 44 ) in the first rotor ( 40 ) toward the outer periphery.
  • the first rotor ( 40 ) rotates to generate the centrifugal force, which causes the lubricant to enter the oil supply passage ( 5 ) from the oil sump ( 44 ), flow toward the outer periphery of the first rotor ( 40 ), and flow from the oil supply port ( 4 ) to be supplied to the sliding surface ( 3 ) of the first rotor ( 40 ). That is, this simple configuration can supply the lubricant to the sliding surface ( 3 ) of the first rotor ( 40 ) by utilizing the centrifugal force generated by the rotation of the first rotor ( 40 ).
  • FIG. 1 is a diagram schematically showing a general configuration of a screw compressor according to a first embodiment.
  • FIG. 2 is a vertical sectional view illustrating the vicinity of a compression mechanism of the screw compressor.
  • FIG. 3 is a cross-sectional view illustrating the vicinity of the compression mechanism of the screw compressor.
  • FIG. 4 is a perspective view illustrating a screw rotor and gate rotors taken out of the screw compressor.
  • FIG. 5 is an enlarged view illustrating a right side portion of FIG. 3 .
  • FIG. 6 is a perspective view illustrating a support member shown in FIG. 5 .
  • FIG. 7 is a vertical sectional view schematically illustrating the gate rotor and the screw rotor meshing with each other in an enlarged scale.
  • FIG. 8 is a sectional view illustrating a gate of the gate rotor and an arm of the support member in a helical groove of the screw rotor.
  • FIG. 9 is an enlarged view of a left side portion of FIG. 3 .
  • FIGS. 10A to 10C are plan views respectively illustrating how a compression mechanism of a single-screw compressor is operated in a suction phase, a compression phase, and a discharge phase.
  • FIG. 11 is a cross-sectional view corresponding to FIG. 5 , illustrating a screw compressor according to a second embodiment.
  • FIG. 12 is a cross-sectional view corresponding to FIG. 9 , illustrating the screw compressor of the second embodiment.
  • FIG. 13 is a vertical sectional view corresponding to FIG. 7 , illustrating the screw compressor of the second embodiment.
  • FIG. 14 is a sectional view taken along line XIV-XIV in FIGS. 11 and 12 .
  • FIG. 15 is a cross-sectional view illustrating the vicinity of a compression mechanism of a screw compressor of a third embodiment.
  • a screw compressor according to a first embodiment is a single-screw compressor ( 1 ) provided in a refrigerant circuit for performing a refrigeration cycle, and compresses a refrigerant (fluid).
  • a compression mechanism ( 20 ) and an electric motor ( 15 ) driving the compression mechanism are housed in a single casing ( 10 ).
  • the single-screw compressor ( 1 ) is configured as a semi-hermetic compressor.
  • the casing ( 10 ) has an outer wall ( 17 ) in the shape of a laterally oriented cylinder. Space inside the casing ( 10 ) is divided into a low-pressure space (S 1 ) located at one of longitudinal ends of the outer wall ( 17 ), and a high-pressure space (S 2 ) located at the other longitudinal end.
  • the casing ( 10 ) is provided with a suction pipe connector ( 11 ) communicating with the low-pressure space (S 1 ), and a discharge pipe connector ( 12 ) communicating with the high-pressure space (S 2 ).
  • a low pressure gas refrigerant flowing from an evaporator of a refrigerant circuit in a refrigeration apparatus, such as a chiller system flows into the low-pressure space (S 1 ) through the suction pipe connector ( 11 ).
  • a compressed, high pressure gas refrigerant discharged from the compression mechanism ( 20 ) into the high-pressure space (S 2 ) passes through the discharge pipe connector ( 12 ), and is supplied to a condenser of the refrigerant circuit.
  • the electric motor ( 15 ) is arranged in the low-pressure space (S 1 ), and the compression mechanism ( 20 ) is arranged between the low-pressure space (S 1 ) and the high-pressure space (S 2 ).
  • the compression mechanism ( 20 ) has a drive shaft ( 21 ) coupled to the electric motor ( 15 ).
  • the electric motor ( 15 ) of the single-screw compressor ( 1 ) is connected to a commercial power supply (not shown).
  • the electric motor ( 15 ) is supplied with an alternating current from the commercial power supply, and rotates at a predetermined rotational speed.
  • an oil separator ( 16 a ) is disposed in the high-pressure space (S 2 ).
  • the oil separator ( 16 a ) separates a lubricant from the refrigerant discharged from the compression mechanism ( 20 ).
  • An oil reservoir chamber ( 16 b ) for storing the lubricant (lubricating oil) is formed in the high-pressure space (S 2 ) below the oil separator ( 16 a ).
  • the lubricant separated from the refrigerant in the oil separator ( 16 a ) flows downward and accumulates in the oil reservoir chamber ( 16 b ).
  • the lubricant accumulated in the oil reservoir chamber ( 16 b ) has high pressure which is substantially equal to the discharge pressure of the refrigerant.
  • the compression mechanism ( 20 ) includes a cylindrical wall (rotor casing) ( 30 ), a single screw rotor (a first rotor) ( 40 ), and two gate rotors (second rotors) ( 50 ) which mesh with the screw rotor ( 40 ).
  • the cylindrical wall ( 30 ) is a cylinder-shaped thick wall, and is integrated with the outer wall ( 17 ) to be part of the casing ( 10 ).
  • the screw rotor ( 40 ) is rotatably housed in the cylindrical wall ( 30 ).
  • a bearing holder ( 35 ) is fitted in a portion of the cylindrical wall ( 30 ) closer to the high-pressure space (S 2 ) of the screw rotor ( 40 ).
  • a drive shaft ( 21 ) arranged coaxially with the screw rotor ( 40 ) is inserted through the screw rotor ( 40 ).
  • the screw rotor ( 40 ) and the drive shaft ( 21 ) are connected to each other by a key ( 22 ).
  • the screw rotor ( 40 ) is driven to rotate in the casing ( 10 ) by the electric motor ( 15 ) disposed on the suction side of the screw rotor ( 40 ).
  • One end of the drive shaft ( 21 ) is supported by the bearing holder ( 35 ) held by the cylindrical wall ( 30 ), via a bearing ( 36 ), and the other end is connected to the electric motor ( 15 ).
  • the screw rotor ( 40 ) is a metal member which is substantially in the shape of a cylindrical column.
  • the screw rotor ( 40 ) is rotatably fitted in the cylindrical wall ( 30 ).
  • the screw rotor ( 40 ) has an outer diameter slightly smaller than an inner diameter of the cylindrical wall ( 30 ), and has an outer peripheral surface ( 43 ) which slides on an inner peripheral surface ( 30 a ) of the cylindrical wall ( 30 ) with a film of the lubricant present therebetween. That is, the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) is configured as a sliding surface ( 3 ) which slides on the inner peripheral surface ( 30 a ) of the cylindrical wall ( 30 ).
  • the screw rotor ( 40 ) has, on its outer periphery, a plurality of helical grooves ( 41 ) (six grooves in this embodiment) helically extending from one axial end of the screw rotor ( 40 ) to the other.
  • Each of the helical grooves ( 41 ) of the screw rotor ( 40 ) has a left end in FIG. 4 serving as a starting end, and a right end in FIG. 4 serving as a terminal end.
  • a left end (an end on the suction side) of the screw rotor ( 40 ) in FIG. 4 is tapered.
  • the starting end of the helical groove ( 41 ) is opened at the tapered left end face of the screw rotor ( 40 ), while the terminal end of the helical groove ( 41 ) is not opened at a right end face of the screw rotor ( 40 ).
  • An inner surface ( 42 ) of the helical groove ( 41 ) includes a lateral face ( 42 a ) on the front side in a direction of rotation of the screw rotor ( 40 ), a lateral face ( 42 b ) on the rear side in the direction of rotation, and a bottom face ( 42 c ) connecting the bottom ends of the lateral faces ( 42 a , 42 b ).
  • each of the gate rotors ( 50 ) is a flat member made of a resin.
  • Each gate rotor ( 50 ) has a plurality of (eleven in this embodiment) gates ( 51 ), each of which is formed in a rectangular plate shape, and a planar coupling portion ( 52 ) coupling base ends of the plurality of gates ( 51 ).
  • the gate rotor ( 50 ) is in the shape of a gear.
  • the two gate rotors ( 50 ) are arranged outside the cylindrical wall ( 30 ) to be axially symmetric with respect to the rotation axis of the screw rotor ( 40 ).
  • the rotation axis of each gate rotor ( 50 ) is in a plane orthogonal to the center axis of the screw rotor ( 40 ).
  • Each of the gate rotors ( 50 ) is attached to a support member ( 55 ) made of metal.
  • the support member ( 55 ) includes a base ( 56 ), arms ( 57 ), and a shaft ( 58 ).
  • the base ( 56 ) is in the shape of a relatively thick disk.
  • the arms ( 57 ) are provided in the same number (eleven in this embodiment) as the gates ( 51 ) of the gate rotor ( 50 ), and extend radially outward from an outer peripheral surface of the base ( 56 ).
  • Each of the arms ( 57 ) abuts on a rear surface of an associated one of the gates ( 51 ), thereby supporting the gate ( 51 ) from the rear side.
  • the shaft ( 58 ) is in a rod shape and coupled to a center portion of the base ( 56 ).
  • the shaft ( 58 ) has a center axis which coincides with the center axis of the base ( 56 ).
  • the shaft ( 58 ) penetrates through the center portion of the gate rotor ( 50 ), and is formed to extend forward and rearward of the gate rotor ( 50 ).
  • the shaft ( 58 ) has a front shaft portion ( 58 a ) which extends forward of the base ( 56 ) and is longer than a rear shaft portion ( 58 b ) which extends rearward of the base ( 56 ).
  • the support members ( 55 ) to each of which the gate rotor ( 50 ) is attached are respectively housed in gate rotor chambers ( 90 ) defined inside the casing ( 10 ) to be adjacent to the cylindrical wall ( 30 ) (see FIG. 3 ).
  • Each of the gate rotor chambers ( 90 ) communicates with the low-pressure space (S 1 ).
  • first and second bearing holders ( 94 , 95 ) formed as an integral part of the casing ( 10 ) are provided in each of the gate rotor chambers ( 90 ).
  • Each of the first and second bearing holders ( 94 , 95 ) has a tubular portion ( 94 a , 95 a ) having a cylindrical shape and a closed bottom, and a flange ( 94 b , 95 b ) formed around a base end of the tubular portion ( 94 a , 95 a ).
  • the tubular portion ( 94 a , 95 a ) of each of the first and second bearing holders ( 94 , 95 ) is inserted into the gate rotor chamber ( 90 ) through an opening formed in the casing ( 10 ), and the flange ( 94 b , 95 b ) is fixed to a portion around the opening of the casing ( 10 ).
  • a bearing ( 92 ) is held at a distal end of the tubular portion ( 94 a ) of the first bearing holder ( 94 ), and a bearing ( 93 ) is held at a distal end of the tubular portion ( 95 a ) of the second bearing holder ( 95 ).
  • the inside of the tubular portion ( 94 a ) of the first bearing holder ( 94 ) serves as an oil sump ( 94 c ) which stores the lubricant to be supplied to the bearing ( 92 ) at the distal end thereof.
  • the inside of the second bearing holder ( 95 ) serves as an oil sump ( 95 c ) which stores the lubricant to be supplied to the bearing ( 93 ) at the distal end thereof.
  • the oil sumps ( 94 c , 95 c ) communicate with the oil reservoir chamber ( 16 b ) formed in the high-pressure space (S 2 ) through a passage (not shown).
  • Each of the oil sumps ( 94 c , 95 c ) stores the high pressure lubricant supplied from the oil reservoir chamber ( 16 b ) through the passage (not shown), and the lubricant reaches a sliding portion of the bearing ( 93 , 94 ) to lubricate the sliding portion.
  • the support member ( 55 ) on the right of the screw rotor ( 40 ) and the support member ( 55 ) on the left of the screw rotor ( 3 ) in FIG. 3 are inverted from each other in the vertical direction. Specifically, the support member ( 55 ) on the right in FIG. 3 has the front shaft portion ( 58 a ) located above the rear shaft portion ( 58 b ) (see FIG. 5 ). The support member ( 55 ) on the left in FIG. 3 has the front shaft portion ( 58 a ) located below the rear shaft portion ( 58 b ) (see FIG. 9 ).
  • each support member ( 55 ) is rotatably supported by the second bearing holder ( 95 ) in each gate rotor chamber ( 90 ) via the bearing ( 93 ), and the rear shaft portion ( 58 b ) of each support member ( 55 ) is rotatably supported by the first bearing holder ( 94 ) in each gate rotor chamber ( 90 ) via the bearing ( 92 ).
  • the casing ( 10 ) is provided with an opening ( 13 ) through which an assembly of the gate rotor ( 50 ) and the support member ( 55 ) can be inserted into the inside of the gate rotor chamber ( 90 ) from the outside of the casing ( 10 ), and a cover member ( 14 ) for covering the opening ( 13 ).
  • the cylindrical wall ( 30 ) has an opening ( 39 ) which allows each of the gate rotor chambers ( 90 ) to communicate with a screw rotor chamber formed inside the cylindrical wall ( 30 ).
  • the assembly of the gate rotor ( 50 ) and the support member ( 55 ) is disposed at a position where the gate ( 51 ) enters the inside of the cylindrical wall ( 30 ) through the opening ( 39 ) and meshes with the screw rotor ( 40 ) (enters the helical groove ( 41 )).
  • the sealing surface ( 39 a ) is a flat surface extending in the axial direction of the screw rotor ( 40 ) along the outer periphery of the screw rotor ( 40 ).
  • a distance between each gate rotor ( 50 ) and the sealing surface ( 39 a ) is set to be very small (e.g., 40 ⁇ m or less) so that the leakage of the fluid compressed in the compression chamber ( 23 ) to the gate rotor chamber ( 90 ) is reduced as much as possible.
  • a space surrounded by the inner peripheral surface ( 30 a ) of the cylindrical wall ( 30 ), the inner surface ( 42 ) forming the helical groove ( 41 ) of the screw rotor ( 40 ), and the front surface ( 51 c ) of the gate ( 51 ) of the gate rotor ( 50 ) functions as the compression chamber ( 23 ) for compressing the fluid.
  • An end of the helical groove ( 41 ) of the screw rotor ( 40 ) on the suction side is opened toward the low-pressure space (S 1 ), and this open end serves as a suction port ( 24 ) of the compression mechanism ( 20 ).
  • the single-screw compressor ( 1 ) is provided with an unloading mechanism ( 70 , 80 ) which controls an operating capacity by performing an unloading operation of returning a portion of the gas in the course of the compression to a low pressure side.
  • the unloading mechanism ( 70 , 80 ) is composed of slide valves ( 70 ) and a slide valve driving mechanism ( 80 ).
  • the slide valves ( 70 ) are respectively arranged in slide valve housings ( 31 ). As shown in FIG. 2 , the slide valve housings ( 31 ) are formed at two positions in the circumferential direction of the cylindrical wall ( 30 ). Each of the slide valves ( 70 ) is configured to be slidable in the axial direction of the cylindrical wall ( 30 ), and faces the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) when the slide valve ( 70 ) is inserted into an associated one of the slide valve housings ( 31 ). The slide valve ( 70 ) is fully opened when it moves to an end toward the discharge side (the right side) in FIG. 2 , or fully closed when it moves to an end toward the suction side.
  • communication passages ( 32 ) are formed outside the cylindrical wall ( 30 ).
  • the communication passages ( 32 ) are formed in one-to-one correspondence with the slide valve housings ( 31 ).
  • Each of the communication passages ( 32 ) has one end opened in the low-pressure space (S 1 ), and the other end opened at an end on the suction side of the corresponding slide valve housing ( 31 ).
  • axial gaps (G) are formed between end faces of the slide valve housings ( 31 ) and end faces of bypass opening degree regulating portions ( 71 ) of the slide valves ( 70 ).
  • Each axial gap (G) forms, together with an associated one of the communication passages ( 32 ), a bypass passage ( 33 ) through which the refrigerant in the course of compression in the compression chamber ( 23 ) is returned to the low-pressure space (S 1 ).
  • the bypass passage ( 33 ) has one end communicating with the low-pressure space (S 1 ) corresponding to the suction side of the compression chamber ( 23 ), and the other end openable at the inner peripheral surface ( 30 a ) of the cylindrical wall ( 30 ) where the compression in the compression chamber ( 23 ) is in progress.
  • Each slide valve ( 70 ) includes the bypass opening degree regulating portion ( 71 ) for regulating the opening degree of the bypass passage ( 33 ), and a discharge opening regulating portion ( 72 ) for regulating an opening area of the discharge port ( 25 ) which is formed in the cylindrical wall ( 30 ) to allow the compression chamber ( 23 ) to communicate with the high-pressure space (S 2 ).
  • the slide valves ( 70 ) are slidable in the axial direction of the screw rotor ( 40 ).
  • the discharge opening regulating portion ( 72 ) of the slide valve ( 70 ) is configured to vary the opening area of the discharge port ( 25 ) in accordance with the change in the position of the slide valve ( 70 ).
  • the slide valve driving mechanism ( 80 ) includes a cylinder tube ( 81 ), a piston ( 82 ) inserted in the cylinder tube ( 81 ), an arm ( 84 ) connected to a piston rod ( 83 ) of the piston ( 82 ), a connecting rod ( 85 ) connecting the arm ( 84 ) and the slide valve ( 70 ), and a spring ( 86 ) for biasing the arm ( 84 ) to the right in FIG. 2 (in a direction in which the arm ( 84 ) is separated from the casing ( 10 )).
  • the cylinder tube ( 81 ) and the piston ( 82 ) are components forming a hydraulic cylinder (hydropneumatic cylinder) ( 87 ).
  • one of axial end portions of the bearing holder ( 35 ) opposite to the screw rotor ( 40 ) is configured as the cylinder tube ( 81 ).
  • the hydraulic cylinder ( 87 ) is disposed across the bearing ( 36 ) from the screw rotor ( 40 ), and is integrated with the bearing holder ( 35 ) holding the bearing ( 36 ).
  • a partition plate ( 38 ) is provided to define a bearing chamber (C 1 ) where the bearing ( 36 ) is held and a cylinder chamber (C 2 ) where the piston ( 82 ) of the hydraulic cylinder ( 87 ) is housed.
  • the slide valve driving mechanism ( 80 ) When the slide valve driving mechanism ( 80 ) is in the state shown in FIG. 2 , the internal pressure of a space in the cylinder chamber (C 2 ) on the left of the piston ( 82 ) (space on the side of the piston ( 82 ) toward the screw rotor ( 40 )) is higher than the internal pressure of a space on the right of the piston ( 82 ) (space on the side of the piston ( 82 ) toward the arm ( 84 )).
  • the slide valve driving mechanism ( 80 ) is configured to adjust the position of the slide valves ( 70 ) by regulating the internal pressure of the space on the right of the piston ( 82 ) (i.e., the gas pressure in the right space).
  • a passage for regulating the pressure in the right space of the piston ( 82 ) is formed in the bearing holder ( 35 ).
  • a suction pressure of the compression mechanism ( 20 ) acts on one of the axial end faces of each slide valve ( 70 ) (i.e., the end face of the bypass opening degree regulating portion ( 71 )), and a discharge pressure of the compression mechanism ( 20 ) acts on the other of the axial end faces of each slide valve ( 70 ). Consequently, during the operation of the single-screw compressor ( 1 ), a force pushing the slide valves ( 70 ) toward the low-pressure space (S 1 ) constantly acts on the slide valves ( 70 ).
  • the single-screw compressor ( 1 ) is provided with an oil supply mechanism ( 60 ) for supplying the lubricant to the side surfaces ( 51 a , 51 b ) and front surface ( 51 c ) of the gate ( 51 ) constituting the sliding surface ( 3 ) of the gate rotor ( 50 ).
  • the oil supply mechanism ( 60 ) is provided for each of the two gate rotors ( 50 ).
  • the oil supply mechanism ( 60 ) which supplies the lubricant to the sliding surface ( 3 ) of the gate rotor ( 50 ) on the right in FIG. 3 , which is enlarged in FIG.
  • each of the two oil supply mechanisms ( 60 ) has an in-shaft communication passage ( 61 ), an oil sump ( 62 ), and a plurality of gate-side oil supply passages ( 63 ) (oil supply passages ( 5 )).
  • the in-shaft communication passage ( 61 ) is formed inside the front shaft portion ( 58 a ).
  • the in-shaft communication passage ( 61 ) includes a longitudinal communication passage ( 61 a ) and two lateral communication passages ( 61 b ).
  • the longitudinal communication passage ( 61 a ) extends straight in the axial direction to pass through the center of the front shaft portion ( 58 a ) from one end to the other end thereof.
  • Each of the two lateral communication passages ( 61 b ) extends from the other end (an end toward the base ( 56 )) of the longitudinal communication passage ( 61 a ) to the outside in a radial direction of the front shaft portion ( 58 a ), and is opened at the outer peripheral surface of the front shaft portion ( 58 a ).
  • the oil sump ( 62 ) is formed between the coupling portion ( 52 ) coupling base ends of the gates ( 51 ) and the base ( 56 ), of the support member ( 55 ), corresponding to the coupling portion ( 52 ).
  • a space defined by a groove ( 62 a ) formed in the coupling portion ( 52 ) of the gate rotor ( 50 ) and a groove ( 62 b ) formed in the base ( 56 ) of the support member ( 55 ) is configured as the oil sump ( 62 ).
  • the groove ( 62 a ) in the gate rotor ( 50 ) and the groove ( 62 b ) in the support member ( 55 ) are formed in an annular shape. As shown in FIG.
  • the groove ( 62 b ) formed in the base ( 56 ) of the support member ( 55 ) is formed in an annular shape to surround the outer periphery of the front shaft portion ( 58 a ), and is opened at the front surface of the base ( 56 ) facing the gate rotor ( 50 ).
  • the two lateral communication passages ( 61 b ) of the in-shaft communication passage ( 61 ) are opened in the groove ( 62 b ). This configuration allows the oil sump ( 62 ) to communicate with the oil sump ( 95 c ) of the second bearing holder ( 95 ) above the front shaft portion ( 58 a ) via the in-shaft communication passage ( 61 ).
  • the gate-side oil supply passages ( 63 ) are respectively formed in the gates ( 51 ) of the gate rotor ( 50 ). In this embodiment, the gate-side oil supply passages ( 63 ) are formed in all of the eleven gates ( 51 ). Each of the gate-side oil supply passages ( 63 ) includes a body ( 53 ), a plurality of lateral branches ( 54 ), and a front branch ( 59 ).
  • grooves ( 63 a ) extending in the radial direction of the gate rotor ( 50 ) are respectively formed in the rear surfaces of the gates ( 51 ).
  • the grooves ( 63 a ) are closed by front surfaces of the arms ( 57 ) respectively supporting the gates ( 51 ) from the rear side.
  • Space in each of the grooves ( 63 a ) closed by the front surfaces of the arms ( 63 ) constitutes the body ( 53 ) of each of the gate-side oil supply passages ( 63 ).
  • the body ( 53 ) of each gate-side oil supply passage ( 63 ) extends radially from the base end to distal end of the gate ( 51 ).
  • a base end of the body ( 53 ) is connected to the oil sump ( 62 ) formed between the coupling portion ( 52 ) coupling the base ends of the gates of the gate rotor ( 50 ) and the base ( 56 ) of the support member ( 55 ).
  • the lateral branches ( 54 ) are formed by holes extending from the body ( 53 ) in the circumferential direction of the gate rotor ( 50 ), and are connected to lateral oil supply ports ( 63 b ) which are opened at side surfaces ( 51 a , 51 b ) of the gate ( 51 ).
  • the lateral oil supply ports ( 63 b ) constitute oil supply ports ( 4 ) for supplying the lubricant to the side surfaces ( 51 a , 51 b ), which are the sliding surfaces ( 3 ), of each gate ( 51 ).
  • each of the gates ( 51 ) is provided with four lateral branches ( 54 ) on the front side, and four lateral branches ( 54 ) on the rear side, in the rotation direction thereof.
  • four lateral oil supply ports ( 63 b ) are opened at the front side surface ( 51 a ) in the rotation direction of the gate ( 51 ), and four lateral oil supply ports ( 63 b ) are opened at the rear side surface ( 51 b ).
  • the four lateral oil supply ports ( 63 b ) at the front side surface ( 51 a ) and the four oil supply ports ( 63 b ) at the rear side surface ( 51 b ) are provided at positions corresponding to each other.
  • the four lateral oil supply ports ( 63 b ) at each side surface ( 51 a , 51 b ) are arranged at substantially equal intervals from the base end to distal end of the gate ( 51 ).
  • the diameter of each of the lateral oil supply ports ( 63 b ) and lateral branches ( 54 ) is determined so that the lubricant flows in such an amount that allows an oil film to be formed on the side surfaces ( 51 a , 51 b ) of the gates ( 51 ), and that the lubricant is kept from scattering in the shape of droplets.
  • the number of lateral oil supply ports ( 63 b ) and lateral branches ( 54 ) is not limited to four, but may be less than four, or more than four.
  • the diameter is changed in accordance with the number so that the lubricant flows in such an amount that allows an oil film to be formed on the side surfaces ( 51 a , 51 b ) of the gates ( 51 ), and that the lubricant is kept from scattering in the shape of droplets.
  • Each of the protruding center portion forms a seal line (L 1 , L 2 ) which abuts on the corresponding lateral face ( 42 a , 42 b ) of the helical groove ( 41 ) of the screw rotor ( 40 ).
  • the lateral oil supply ports ( 63 b ) are opened at the side surfaces ( 51 a , 51 b ) of each gate ( 51 ) at a position forward of the seal line (L 1 . L 2 ), that is, toward the compression chamber ( 23 ).
  • each of the gate-side oil supply passages ( 63 ) is connected to the lateral oil supply ports ( 63 b ) opened at the side surfaces ( 51 a , 51 b ) of the gate ( 51 ) which slide on the screw rotor ( 40 ).
  • the front branch ( 59 ) is a hole which extends in a thickness direction of the gate ( 51 ) (a direction parallel to the axial direction of the gate rotor ( 50 )) from the groove ( 63 a ) (body ( 53 )) extending in the radial direction of the gate rotor ( 50 ) of the gate ( 51 ), and is opened at the front surface ( 51 c ).
  • the front branch ( 59 ) is connected to a front oil supply port ( 63 c ) opened at the front surface ( 51 c ) of the gate ( 51 ).
  • the front oil supply port ( 63 c ) constitutes an oil supply port ( 4 ) for supplying the lubricant to the front surface ( 51 c ), which is the sliding surface ( 3 ), of the gate ( 51 ).
  • the front branch ( 59 ) is provided for each of the plurality of gates ( 51 ).
  • a single front oil supply port ( 63 c ) is opened at each of the front surfaces ( 51 c ) of the gates ( 51 ).
  • each of the front oil supply ports ( 63 c ) is opened at a position further inward than the center of the front surface ( 51 c ) of the gate ( 51 ) in the radial direction.
  • each of the front oil supply ports ( 63 c ) and front branches ( 59 ) is determined so that the lubricant flows in such an amount that allows an oil film to be formed on the front surfaces ( 51 c ) of the gates ( 51 ), and that the lubricant is kept from scattering in the shape of droplets.
  • the number of front oil supply ports ( 63 c ) and front branches ( 59 ) is not limited to one, but may be two or more. In a preferred embodiment, the diameter is changed in accordance with the number so that the oil film is formed on the front surfaces ( 51 c ) of the gates ( 51 ).
  • each of the gate-side oil supply passages ( 63 ) is connected to the front oil supply port ( 63 c ) opened at the front surface ( 51 c ) of the gate ( 51 ) facing the compression chamber ( 23 ).
  • the lubricant passage has an inlet which is opened in the oil sump ( 95 c ) of the second bearing holder ( 95 ) in which the high pressure lubricant flowing from the oil reservoir chamber ( 16 b ) is accumulated.
  • the in-shaft communication passage ( 61 ) is formed inside the rear shaft portion ( 58 b ).
  • the in-shaft communication passage ( 61 ) includes a longitudinal communication passage ( 61 a ) and two lateral communication passages ( 61 b ).
  • the longitudinal communication passage ( 61 a ) extends straight in the axial direction to pass through the center of the rear shaft portion ( 58 b ) from one end to the other end thereof.
  • Each of the two lateral communication passages ( 61 b ) extends from the other end (an end toward the base ( 56 )) of the longitudinal communication passage ( 61 a ) to the outside in a radial direction of the rear shaft portion ( 58 b ), and is opened at the outer peripheral surface of the rear shaft portion ( 58 b ).
  • the oil sump ( 62 ) is formed between the coupling portion ( 52 ) coupling base ends of the gate rotor ( 50 ) and the base ( 56 ), of the support member ( 55 ), corresponding to the coupling portion ( 52 ).
  • a space defined by a groove ( 62 a ) formed in the coupling portion ( 52 ) of the gate rotor ( 50 ) and a groove ( 62 b ) formed in the base ( 56 ) of the support member ( 55 ) is configured as the oil sump ( 62 ).
  • the groove ( 62 a ) in the gate rotor ( 50 ) and the groove ( 62 b ) in the support member ( 55 ) are formed in an annular shape.
  • the groove ( 62 b ) formed in the base ( 56 ) of the support member ( 55 ) is in an annular shape to surround the outer periphery of the rear shaft portion ( 58 b ), and is opened at the front surface of the base ( 56 ) facing the gate rotor ( 50 ).
  • the two lateral communication passages ( 61 b ) of the in-shaft communication passage ( 61 ) are opened in the groove ( 62 b ). This configuration allows the oil sump ( 62 ) to communicate with the oil sump ( 94 c ) of the first bearing holder ( 94 ) above the rear shaft portion ( 58 b ) via the in-shaft communication passage ( 61 ).
  • the gate-side oil supply passages ( 63 ) are respectively formed in the gates ( 51 ) of the gate rotor ( 50 ). In this embodiment, the gate-side oil supply passages ( 63 ) are formed in all of the eleven gates ( 51 ). Each of the gate-side oil supply passages ( 63 ) includes a body ( 53 ), a plurality of lateral branches ( 54 ), and a front branch ( 59 ).
  • grooves ( 63 a ) extending in the radial direction of the gate rotor ( 50 ) are formed in the rear surfaces of the gates ( 51 ).
  • the grooves ( 63 a ) are closed by front surfaces of the arms ( 57 ) respectively supporting the gates ( 51 ) from the rear side.
  • Space in each of the grooves ( 63 a ) closed by the front surfaces of the arms ( 57 ) constitutes the body ( 53 ) of each of the gate-side oil supply passages ( 63 ).
  • the body ( 53 ) of each gate-side oil supply passage ( 63 ) extends radially from the base end to distal end of the gate ( 51 ).
  • a base end of the body ( 53 ) is connected to the oil sump ( 62 ) formed between the coupling portion ( 52 ) coupling the base ends of the gates of the gate rotor ( 50 ) and the base ( 56 ) of the support member ( 55 ).
  • the lateral branches ( 54 ) are formed by holes extending from the body ( 53 ) of the gate ( 51 ) in the circumferential direction of the gate rotor ( 50 ), and are connected to lateral oil supply ports ( 63 b ) which are opened at the side surfaces ( 51 a , 51 b ) of the gate ( 51 ).
  • the lateral oil supply ports ( 63 b ) constitute oil supply ports ( 4 ) for supplying the lubricant to the side surfaces ( 51 a , 51 b ), which are the sliding surfaces ( 3 ), of the gate ( 51 ).
  • each of the gates ( 51 ) is provided with four lateral branches ( 54 ) on the front side, and four lateral branches ( 54 ) on the rear side, in the rotation direction thereof.
  • four lateral oil supply ports ( 63 b ) are opened at the front side surface ( 51 a ) in the rotation direction of the gate ( 51 ), and four lateral oil supply ports ( 63 b ) are opened at the rear side surface ( 51 b ).
  • the four lateral oil supply ports ( 63 b ) at the front side surface ( 51 a ) and the four oil supply ports ( 63 b ) at the rear side surface ( 51 b ) are provided at positions corresponding to each other.
  • the four lateral oil supply ports ( 63 b ) at each side surface ( 51 a , 51 b ) are arranged at substantially equal intervals from the base end to distal end of the gate ( 51 ).
  • the diameter of each of the lateral oil supply ports ( 63 b ) and lateral branches ( 54 ) is determined so that the lubricant flows in such an amount that allows an oil film to be formed on the side surfaces ( 51 a , 51 b ) of the gates ( 51 ), and that the lubricant is kept from scattering in the shape of droplets.
  • the number of lateral oil supply ports ( 63 b ) and lateral branches ( 54 ) is not limited to four, but may be less than four, or more than four.
  • the diameter is changed in accordance with the number so that the lubricant flows in such an amount that allows an oil film to be formed on the side surfaces ( 51 a , 51 b ) of the gates ( 51 ), and that the lubricant is kept from scattering in the shape of droplets.
  • Each of the protruding center portion forms a seal line (L 1 , L 2 ) which abuts on the corresponding lateral face ( 42 a , 42 b ) of the helical groove ( 41 ) of the screw rotor ( 40 ).
  • the lateral oil supply ports ( 63 b ) are opened at the side surfaces ( 51 a , 51 b ) of each gate ( 51 ) at a position forward of the seal line (L 1 , L 2 ), that is, toward the compression chamber ( 23 ).
  • each of the gate-side oil supply passages ( 63 ) is connected to the lateral oil supply ports ( 63 b ) opened at the side surfaces ( 51 a , 51 b ) of the gate ( 51 ) which slide on the screw rotor ( 40 ).
  • the front branch ( 59 ) is a hole which extends in a thickness direction of the gate ( 51 ) (a direction parallel to the axial direction of the gate rotor ( 50 )) from the groove ( 63 a ) (body ( 53 )) extending in the radial direction of the gate rotor ( 50 ) of the gate ( 51 ), and is opened at the front surface ( 51 c ).
  • the front branch ( 59 ) is connected to a front oil supply port ( 63 c ) opened at the front surface ( 51 c ) of the gate ( 51 ).
  • the front oil supply port ( 63 c ) constitutes an oil supply port ( 4 ) for supplying the lubricant to the front surface ( 51 c ), which is the sliding surface ( 3 ), of the gate ( 51 ).
  • the front branch ( 59 ) is provided for each of the plurality of gates ( 51 ).
  • a single front oil supply port ( 63 c ) is opened at each of the front surfaces ( 51 c ) of the gates ( 51 ).
  • each of the front oil supply ports ( 63 c ) is opened at a position further inward than the center of the front surface ( 51 c ) of the gate ( 51 ) in the radial direction.
  • each of the front oil supply ports ( 63 c ) and front branches ( 59 ) is determined so that the lubricant flows in such an amount that allows an oil film to be formed on the front surfaces ( 51 c ) of the gates ( 51 ), and that the lubricant is kept from scattering in the shape of droplets.
  • the number of front oil supply ports ( 63 c ) and front branches ( 59 ) is not limited to one, but may be two or more. In a preferred embodiment, the diameter is changed in accordance with the number so that the oil film is formed on the front surfaces ( 51 c ) of the gates ( 51 ).
  • each of the gate-side oil supply passages ( 63 ) is connected to the front oil supply port ( 63 c ) opened at the front surface ( 51 c ) of the gate ( 51 ) facing the compression chamber ( 23 ).
  • the lubricant passage has an inlet which is opened in the oil sump ( 94 c ) of the first bearing holder ( 94 ) in which the high pressure lubricant flowing from the oil reservoir chamber ( 16 b ) is accumulated.
  • the compression chamber ( 23 ) dotted in FIG. 10A communicates with the low-pressure space (S 1 ).
  • the gate ( 51 ) of the lower gate rotor ( 50 ) in FIG. 10A meshes with the corresponding helical groove ( 41 ) which defines the compression chamber ( 23 ).
  • the gate ( 51 ) relatively moves within the helical groove ( 41 ) toward the terminal end of the helical groove ( 41 ), causing the capacity of the compression chamber ( 23 ) to gradually increase.
  • the low pressure gas refrigerant in the low-pressure space (S 1 ) is sucked into the compression chamber ( 23 ) through the suction port ( 24 ).
  • FIG. 10B When the screw rotor ( 40 ) further rotates, the operation enters the state of FIG. 10B .
  • the compression chamber ( 23 ) dotted in FIG. 10B is fully closed.
  • the gate ( 51 ) of the upper gate rotor ( 50 ) in FIG. 10B meshes with the corresponding helical groove ( 41 ) which defines the compression chamber ( 23 ), and the compression chamber ( 23 ) is partitioned from the low-pressure space (S 1 ) by the gate ( 51 ).
  • the gate ( 51 ) relatively moves within the helical groove ( 41 ) toward the terminal end of the helical groove ( 41 ), causing the capacity of the compression chamber ( 23 ) to gradually decrease.
  • the low pressure gas refrigerant in the compression chamber ( 23 ) is gradually compressed.
  • the capacity of the compression mechanism ( 20 ) is controlled using the slide valve ( 70 ).
  • the slide valve ( 70 ) comes to the end where the slide valve ( 70 ) is fully closed (suction side). In this state, the capacity of the compression mechanism ( 20 ) is maximized.
  • the tip end face of the slide valve ( 70 ) releases the axial gap (G), and the bypass passage ( 33 ) opens at the inner peripheral surface of the cylindrical wall ( 30 ).
  • the two oil supply mechanisms ( 60 ) supply the lubricant to the sliding surfaces ( 3 ) of the two gate rotors ( 50 ) and the screw rotor ( 40 ).
  • the pressure difference between the inlet and outlets of the lubricant passage formed by the in-shaft communication passage ( 61 ), the oil sump ( 62 ), and the plurality of gate-side oil supply passages ( 63 ) causes the lubricant supplied to each oil sump ( 94 c , 95 c ) from the oil reservoir chamber ( 16 b ) to enter the lubricant passage, and flow toward the outlets.
  • the lubricant in the oil sump ( 94 c , 95 c ) flows into the longitudinal communication passage ( 61 a ) of the in-shaft communication passage ( 61 ) inside the front shaft portion ( 58 a ), diverges from the longitudinal communication passage ( 61 a ) to the two lateral communication passages ( 61 b ), and eventually flows into the oil sump ( 62 ) (see FIGS. 5, 6, and 9 ).
  • the lubricant that has reached the oil sump ( 62 ) flows into the plurality of gate-side oil supply passages ( 63 ) extending radially from the oil sump ( 62 ) by the effect of the driving force caused by the pressure difference described above and the centrifugal force generated by the rotation of the gate rotor ( 50 ) and the support member ( 55 ), and then flows radially outward in each of the gate-side oil supply passages ( 63 ) (see FIGS. 5 and 9 ).
  • the lubricant flowing through the gate-side oil supply passages ( 63 ) flows to the side surfaces ( 51 a , 51 b ) of the gate ( 51 ) from the plurality of lateral oil supply ports ( 63 b ), and to the front surface ( 51 c ) of the gate ( 51 ) from the front oil supply port ( 63 c ).
  • each gate ( 51 ) From the lateral oil supply ports ( 63 b ) of each gate ( 51 ), the lubricant flows in such an amount that allows an oil film to be formed on the side surfaces ( 51 a , 51 b ) of the gate ( 5 ).
  • the lubricant that has flowed from the plurality of lateral oil supply ports ( 63 b ) is spread radially outward on the side surfaces ( 51 a , 51 b ) of the gates ( 51 ) by the effect of the centrifugal force to form the oil film on each of the side surfaces ( 51 a , 51 b ).
  • the lateral oil supply ports ( 63 b ) are opened at each of the side surfaces ( 51 a , 51 b ) of the gate ( 51 ) at a position forward of the seal line (L 1 , L 2 ) which abuts on the corresponding lateral face ( 42 a , 42 b ) of the helical groove ( 41 ) of the screw rotor ( 40 ), that is, further toward the compression chamber ( 23 ) than the seal line.
  • the lubricant is supplied to a portion of the side surface ( 51 a , 51 b ) forward of the seal line (L 1 , L 2 ) of each gate ( 51 ) in the traveling direction of the gate ( 51 ) when the gate travels toward the compression chamber ( 23 ) in the helical groove ( 41 ) of the screw rotor ( 40 ).
  • the lubricant is reliably supplied to the seal line (L 1 , L 2 ) of each gate ( 51 ) which slides on the corresponding lateral face ( 42 a , 42 b ) of the helical groove ( 41 ) of the screw rotor ( 40 ).
  • the lubricant that has flowed from the lateral oil supply ports ( 63 b ) to the side surfaces ( 51 a , 51 b ) of the gates ( 51 ) and supplied to the sliding surfaces ( 3 ) of the screw rotor ( 40 ) adheres to the screw rotor ( 40 ), and is spread to the outer periphery of the screw rotor by the effect of the centrifugal force generated by the rotation of the screw rotor ( 40 ).
  • the lubricant flows from the front oil supply port ( 63 c ) of each of the gates ( 51 ) in such an amount that allows an oil film to be formed on the front surface ( 51 c ) of the gate ( 51 ).
  • the lubricant that has flowed from the front oil supply port ( 63 c ) is spread radially outward on the front surface ( 51 c ) of the gate ( 51 ) by the effect of the centrifugal force to form an oil film on the front surface ( 51 c ).
  • each of the front oil supply ports ( 63 c ) is opened at a position inward of the center of the front surface ( 51 c ) of each gate ( 51 ) in the radial direction (see FIG. 7 ). Therefore, the lubricant that has flowed from the front oil supply port ( 63 c ) on the front surface ( 51 c ) of the gate ( 51 ) is spread widely outward from the radially inward position.
  • the rotation of the gate rotor ( 50 ) causes each of the gates ( 51 ) to come in and out of the cylindrical wall ( 30 ) via the opening ( 39 ) of the cylindrical wall ( 30 ).
  • the lubricant flowed from the front oil supply port ( 63 c ) is widely spread over the front surface ( 51 c ) of each gate ( 51 ), and is supplied between the front surface ( 51 c ) of the gate ( 51 ) and the sealing surface ( 39 a ) of the cylindrical wall ( 30 ) facing each other.
  • the lubricant lubricates the front surface ( 51 c ) of the gate ( 51 ) and the sealing surface ( 39 a ) of the cylindrical wall ( 30 ), which are the sliding surfaces, and seals a gap therebetween.
  • This keeps the gates ( 51 ) from seizing, and blocks the gas refrigerant in the high pressure compression chamber ( 23 ) from leaking to the gate rotor chamber ( 90 ) through the gap between the front surface ( 51 c ) of the gate ( 51 ) and the sealing surface ( 39 a ) of the cylindrical wall ( 30 ).
  • each of the gates ( 51 ) of the gate rotor ( 50 ) is provided with the gate-side oil supply passage ( 63 ) directly supplying the lubricant to the side surfaces ( 51 a . 51 b ) which slide on the screw rotor ( 51 ) and need to be lubricated and sealed by the lubricant.
  • the lubricant can be reliably supplied to the sliding surfaces ( 3 ) of the gate ( 51 ) and the screw rotor ( 40 ) in a smaller amount, thereby lubricating the gate ( 51 ) and the screw rotor ( 40 ) and sealing the gap therebetween.
  • the lubricant supplied in this manner to the sliding surfaces ( 3 ) of the screw rotor ( 40 ) and the gate ( 51 ) also adheres to the screw rotor ( 40 ), and is spread toward the outer periphery of the screw rotor ( 40 ) by the effect of the centrifugal force generated by the rotation of the screw rotor ( 40 ).
  • the lubricant can also be supplied to a gap between the screw rotor ( 40 ) and the cylindrical wall ( 30 ) to seal the gap.
  • the efficiency of the compressor is not lowered because it is unnecessary to increase the power for the transport of the lubricant and the power for the rotation of the screw rotor ( 40 ), unlike the conventional configuration in which a large amount of lubricant is supplied.
  • Directly supplying the lubricant in a small amount to the sliding surfaces ( 3 ) of the gate ( 51 ) and the screw rotor ( 40 ) makes it possible to lubricate the gate ( 51 ) and the screw rotor ( 40 ), and the screw rotor ( 40 ) and the cylindrical wall ( 30 ), and to seal the gap between the gate ( 51 ) and the screw rotor ( 40 ), and the gap between the screw rotor ( 40 ) and the cylindrical wall ( 30 ). That is, according to this embodiment, the gate rotor ( 50 ) and the screw rotor ( 40 ) can be protected from the sliding wear, and a high pressure fluid can be blocked from leaking from the compression chamber, even if the supply amount of the lubricant is reduced. Therefore, in the present embodiment, the supply amount of the lubricant can be reduced without lowering the reliability of the single-screw compressor ( 1 ), which can improve the compressor efficiency.
  • the gate-side oil supply passage ( 63 ) of the gate ( 51 ) is provided with not only the lateral oil supply ports ( 63 b ) which are opened at the side surfaces ( 51 a , 51 b ) that slide on the screw rotor ( 40 ) of the gate ( 51 ), but also the front oil supply port ( 63 c ) which is opened at the front surface ( 51 c ) of the gate ( 51 ).
  • the lubricant in the gate-side oil supply passage ( 63 ) can be supplied not only to the side surfaces ( 51 a , 51 b ) that slide on the screw rotor ( 40 ), but also to the front surface ( 51 c ) that faces the compression chamber ( 23 ).
  • the lubricant is supplied between the front surface ( 51 c ) of the gate ( 51 ) sliding on the surface of the cylindrical wall ( 30 ), which lubricates these sliding surfaces, and seals a gap between them.
  • the oil sump ( 62 ) is formed between the support member ( 55 ) supporting the gate rotor ( 50 ) and the coupling portion ( 52 ) of the gate rotor ( 50 ) coupling the base ends of the gates, and a base end of the gate-side oil supply passage ( 63 ) in the gate ( 51 ) is connected to the oil sump ( 62 ). That is, the gate-side oil supply passage ( 63 ) extends radially outward from the oil sump ( 62 ) along the corresponding gate ( 51 ).
  • the gate rotor ( 50 ) rotates to generate the centrifugal force, which causes the lubricant in the oil sump ( 62 ) to enter and flow radially outward through the gate-side oil supply passage ( 63 ) of the gate ( 51 ), and flow from the lateral oil supply ports ( 63 b ). That is, this simple configuration can supply the lubricant to the sliding surfaces ( 3 ) by utilizing the centrifugal force generated by the rotation of the gate rotor ( 50 ).
  • the oil supply mechanism ( 60 ) and first and second bearing holders ( 94 , 95 ) of the single-screw compressor ( 1 ) of the first embodiment are partially modified so that the lubricant is supplied intermittently as needed to the sliding surfaces ( 3 ) of the gate rotors ( 50 ).
  • the single-screw compressor of the second embodiment has two oil supply mechanisms ( 60 ), each of which includes a plurality of in-shaft communication passages ( 61 ), a plurality of oil sumps ( 62 ), and a plurality of gate-side oil supply passages ( 63 ).
  • eleven in-shaft communication passages ( 61 ), eleven oil sumps ( 62 ), and eleven gate-side oil supply passages ( 63 ) are provided.
  • the right oil supply mechanism ( 60 ) includes a plurality of in-shaft communication passages ( 61 ) formed inside the front shaft portion ( 58 a ).
  • the left oil supply mechanism ( 60 ) includes a plurality of in-shaft communication passages ( 61 ) formed inside the rear shaft portion ( 58 b ).
  • Each of the in-shaft communication passages ( 61 ) includes a longitudinal communication passage ( 61 a ) and a lateral communication passage ( 61 b ), and is formed in an L-shape.
  • each of the longitudinal communication passages ( 61 a ) in the right oil supply mechanism ( 60 ) extends straight in the axial direction to pass through an outer peripheral portion of the front shaft portion ( 58 a ) from one end to the other end thereof.
  • each of the longitudinal communication passages ( 61 a ) in the left oil supply mechanism ( 60 ) extends straight in the axial direction to pass through an outer peripheral portion of the rear shaft portion ( 58 b ) from one end to the other end thereof.
  • each of the lateral communication passages ( 61 b ) in the right oil supply mechanism ( 60 ) extends outward in the radial direction of the front shaft portion ( 58 a ) from the other end (an end toward the base ( 56 )) of an associated one of the longitudinal communication passages ( 61 a ), and is opened at an outer peripheral surface of the front shaft portion ( 58 a ). As shown in FIG. 11 , each of the lateral communication passages ( 61 b ) in the right oil supply mechanism ( 60 ) extends outward in the radial direction of the front shaft portion ( 58 a ) from the other end (an end toward the base ( 56 )) of an associated one of the longitudinal communication passages ( 61 a ), and is opened at an outer peripheral surface of the front shaft portion ( 58 a ). As shown in FIG. 11 , each of the lateral communication passages ( 61 b ) in the right oil supply mechanism ( 60 ) extends outward in the radial direction of the front shaft portion
  • each of the lateral communication passages ( 61 b ) in the left oil supply mechanism ( 60 ) extends outward in the radial direction of the rear shaft portion ( 58 b ) from the other end (an end toward the base ( 56 )) of an associated one of the longitudinal communication passages ( 61 a ), and is opened at an outer peripheral surface of the rear shaft portion ( 58 b ).
  • the in-shaft communication passages ( 61 ) are formed in the same number (eleven) as the gates ( 51 ) to be in one-to-one correspondence with the eleven gates ( 51 ).
  • the eleven in-shaft communication passages ( 61 ) are provided at equal intervals in the circumferential direction of the front shaft portion ( 58 a ) or the rear shaft portion ( 58 b ) so that each of the eleven lateral communication passages ( 61 b ) extends in the direction of extension of the corresponding gate ( 51 ).
  • the plurality of oil sumps ( 62 ) are formed between a coupling portion ( 52 ) coupling base ends of the gates of the gate rotor ( 50 ) and the base ( 56 ), of the support member ( 55 ), corresponding to the coupling portion ( 52 ).
  • a plurality of grooves ( 62 a ) formed in the coupling portion ( 52 ) of the gate rotor ( 50 ) and a plurality of grooves ( 62 b ) formed in the base ( 56 ) of the support member ( 55 ) form a plurality of spaces, which respectively constitute the oil sumps ( 62 ).
  • the grooves ( 62 a ) of the gate rotor ( 50 ) and the grooves ( 62 b ) of the support member ( 55 ) are formed in the same number (eleven) as the gates ( 51 ) to be in one-to-one correspondence with the gates ( 51 ).
  • the eleven grooves ( 62 b ) formed in the base ( 56 ) of the support member ( 55 ) extend radially outward from the outer peripheral surface of the front shaft portion ( 58 a ), and are opened at the front surface of the base ( 56 ) facing the gate rotor ( 50 ).
  • the eleven grooves ( 62 b ) formed in the base ( 56 ) of the support member ( 55 ) extend radially outward from the outer peripheral surface of the rear shaft portion ( 58 b ), and are opened at the front surface of the base ( 56 ) facing the gate rotor ( 50 ).
  • each of the eleven lateral communication passages ( 61 b ) of the in-shaft communication passage ( 61 ) is opened in an associated one of the grooves ( 62 b ).
  • each oil supply mechanism ( 60 ) the gate-side oil supply passages ( 63 ) are respectively formed in the gates ( 51 ) of the gate rotor ( 50 ). Also in the second embodiment, the gate-side oil supply passages ( 63 ) are formed in all of the eleven gates ( 51 ). In each of the oil supply mechanisms ( 60 ) of the second embodiment, the eleven gate-side oil supply passages ( 63 ) are formed in one-to-one correspondence with the eleven oil sumps ( 62 ). Each of the gate-side oil supply passages ( 63 ) includes a body ( 53 ), a plurality of lateral branches ( 54 ), and a front branch ( 59 ).
  • grooves ( 63 a ) extending in the radial direction of each gate rotor ( 50 ) are formed in the rear surfaces of the gates ( 51 ).
  • the grooves ( 63 a ) formed in the gates ( 51 ) are formed in one to-one correspondence with the eleven grooves ( 62 a ) formed in the coupling portion ( 52 ) of the gate rotor ( 50 ), and are integrated with the corresponding grooves ( 62 a ).
  • the grooves ( 63 a ) formed in the gates ( 51 ) are closed 251 by front surfaces of the arms ( 57 ) respectively supporting the gates ( 51 ) from the rear side.
  • each gate-side oil supply passage ( 63 ) Space in each of the grooves ( 63 a ) closed by the front surfaces of the arms ( 57 ) constitutes the body ( 53 ) of each of the gate-side oil supply passages ( 63 ).
  • the body ( 53 ) of each gate-side oil supply passage ( 63 ) extends radially from a base end to distal end of the gate ( 51 ).
  • a base end of the body ( 53 ) is connected to the oil sump ( 62 ) formed between the coupling portion ( 52 ) coupling the base ends of the gates of the gate rotor ( 50 ) and the base ( 56 ), of the support member ( 55 ), corresponding to the coupling portion ( 52 ).
  • each of the oil supply mechanisms ( 60 ) the lateral branches ( 54 ) are formed by holes extending from each body ( 53 ) of the gate ( 51 ) in the circumferential direction of the gate rotor ( 50 ), and are connected to lateral oil supply ports ( 63 b ), which are oil supply ports ( 4 ) opened at the side surfaces ( 51 a , 51 b ) of the gate ( 51 ).
  • each of the gates ( 51 ) is provided with four lateral branches ( 54 ) on the front side, and four lateral branches ( 54 ) on the rear side, in the rotation direction thereof.
  • four lateral oil supply ports ( 63 b ) are opened at the front side surface ( 51 a ) in the rotation direction of the gate ( 51 ), and four lateral oil supply ports ( 63 b ) are opened at the rear side surface ( 51 b ).
  • the four lateral oil supply ports ( 63 b ) at the front side surface ( 51 a ) and the four oil supply ports ( 63 b ) at the rear side surface ( 51 b ) are provided at positions corresponding to each other.
  • the four lateral oil supply ports ( 63 b ) at each side surface ( 51 a , 51 b ) are arranged at substantially equal intervals from the base end to distal end of the gate ( 51 ).
  • each of the lateral oil supply ports ( 63 b ) and lateral branches ( 54 ) is determined so that the lubricant flows in such an amount that allows an oil film to be formed on the side surfaces ( 51 a , 51 b ) of the gates ( 51 ), and that the lubricant is kept from scattering in the shape of droplets.
  • the number of lateral oil supply ports ( 63 b ) and lateral branches ( 54 ) is not limited to four, but may be less than four, or more than four.
  • the diameter is changed in accordance with the number so that the lubricant flows in such an amount that allows an oil film to be formed on the side surfaces ( 51 a , 51 b ) of the gates ( 51 ), and that the lubricant is kept from scattering in the shape of droplets.
  • each of the side surfaces ( 51 a , 51 b ) of the gate ( 51 ) which slides on the screw rotor ( 40 ) protrudes at a center portion in the thickness direction of the gate.
  • Each of the protruding center portion forms a seal line (L 1 , L 2 ) which abuts on the corresponding lateral face ( 42 a , 42 b ) of the helical groove ( 41 ) of the screw rotor ( 40 ).
  • the lateral oil supply ports ( 63 b ) are opened at the side surfaces ( 51 a . 51 b ) of each gate ( 51 ) at a position forward of the seal line (L 1 , L 2 ), that is, toward the compression chamber ( 23 ).
  • each of the gate-side oil supply passages ( 63 ) in the oil supply mechanisms ( 60 ) is connected to the lateral oil supply ports ( 63 b ) opened at the side surfaces ( 51 a , 51 b ) of the gate ( 51 ) which slide on the screw rotor ( 40 ).
  • the front branch ( 59 ) of the second embodiment is a hole which extends in a thickness direction of the gate ( 51 ) (a direction parallel to the axial direction of the gate rotor ( 50 )) from the groove ( 63 a ) (body ( 53 )) extending in the radial direction of the gate rotor ( 50 ) of the gate ( 51 ), and is opened at the front surface ( 51 c ).
  • the front branch ( 59 ) is connected to a front oil supply port ( 63 c ) which is the oil supply port ( 4 ) opened at the front surface ( 51 c ) of the gate ( 51 ).
  • the front branches ( 59 ) are respectively provided for the plurality of gates ( 51 ), and thus, a single front oil supply port ( 63 c ) is opened at each of the front surfaces ( 51 c ) of the gates ( 51 ).
  • Each of the front oil supply ports ( 63 c ) is opened at a position further inward than the center of the front surface ( 51 c ) of the gate ( 51 ) in the radial direction.
  • the diameter of each of the front oil supply ports ( 63 c ) and front branches ( 59 ) is determined so that the lubricant flows in such an amount that allows an oil film to be formed on the front surfaces ( 51 c ) of the gates ( 51 ), and that the lubricant is kept from scattering in the shape of droplets.
  • the number of front oil supply ports ( 63 c ) and front branches ( 59 ) is not limited to one, but may be two or more.
  • the diameter is changed in accordance with the number so that the oil film is formed on the front surfaces ( 51 c ) of the gates ( 51 ).
  • the gate-side oil supply passages ( 63 ) in each of the oil supply mechanisms ( 60 ) are connected to the front oil supply ports ( 63 c ) each of which is opened at the front surface ( 51 c ) of the gate ( 51 ) facing the compression chamber ( 23 ).
  • each of the first and second bearing holders ( 94 , 95 ) has a tubular portion ( 94 a , 95 a ) having a cylindrical shape and a closed bottom, a flange ( 94 b , 95 b ) formed around a base end of the tubular portion ( 94 a , 95 a ), and a closing portion ( 94 d , 95 d ).
  • the tubular portions ( 94 a , 95 a ) and the flanges ( 94 b , 95 b ) are configured in the same manner as those of the first embodiment.
  • the closing portion ( 95 d ) of the second bearing holder ( 95 ) protrudes downward from an inner bottom surface of the tubular portion ( 95 a ), and abuts on a top surface of the front shaft portion ( 58 a ) of the support member ( 55 ) by a lower end thereof, thereby closing inlets of some of the eleven in-shaft communication passages ( 61 ) (inlets of the longitudinal communication passages ( 61 a )) formed inside the front shaft portion ( 58 a ) of the support member ( 55 ).
  • FIG. 11 in the right oil supply mechanism ( 60 ), the closing portion ( 95 d ) of the second bearing holder ( 95 ) protrudes downward from an inner bottom surface of the tubular portion ( 95 a ), and abuts on a top surface of the front shaft portion ( 58 a ) of the support member ( 55 ) by a lower end thereof, thereby closing inlets of some of the eleven in-shaft communication passages ( 61 ) (inlets of the
  • the closing portion ( 94 d ) of the first bearing holder ( 94 ) protrudes downward from an inner bottom surface of the tubular portion ( 94 a ), and abuts on a top surface of the rear shaft portion ( 58 b ) by a lower end thereof, thereby closing inlets of some of the eleven in-shaft communication passages ( 61 ) (inlets of the longitudinal communication passages ( 61 a )) formed inside the rear shaft portion ( 58 b ) of the support member ( 55 ).
  • the closing portion ( 94 d , 95 d ) of the bearing holder ( 194 , 95 ) is configured to keep four of the inlets ( 61 a - 1 to 61 a - 11 ) of the eleven in-shaft communication passages ( 61 ) in the front shaft portion ( 58 a ) or the rear shaft portion ( 58 b ) closer to the screw rotor ( 40 ) open, and close the remaining seven inlets.
  • the oil sump ( 94 c , 95 c ) formed in each of the first and second bearing holders ( 94 , 95 ) is formed to have a wider portion on the side closer to the screw rotor ( 40 ), and a narrower portion on the other side.
  • the front shaft portion ( 58 a ) or the rear shaft portion ( 58 b ) in which the in-shaft communication passages ( 58 ) are formed rotates in accordance with the rotation of the gate rotors ( 50 ), but the closing portion ( 94 d . 95 d ) is fixed and does not rotate. Therefore, the inlets ( 61 a - 1 to 61 a - 11 ) of the in-shaft communication passages ( 61 ) to be closed by the closing portions ( 94 d , 95 d ) change in accordance with the rotational angle position of the gate rotor ( 50 ).
  • the closing portion ( 94 d , 95 d ) closes the fifth to eleventh inlets ( 61 a - 5 to 61 a - 11 ), while keeping the first to fourth inlets ( 61 a - 1 to 61 a - 4 ) open.
  • the first to fourth inlets ( 61 a - 1 to 61 a - 4 ) are opened to the oil sump ( 94 c , 95 c ).
  • the closing portion ( 94 d , 95 d ) closes the fourth to tenth inlets ( 61 a - 4 to 61 a - 10 ), while keeping the first to third inlets ( 61 a - 1 to 61 a - 3 ) and the eleventh inlet ( 61 a - 11 ) open.
  • the first to third inlets ( 61 a - 1 to 61 a - 3 ) and the eleventh inlet ( 61 a - 11 ) are opened in the oil sump ( 94 c , 95 c ).
  • the inlets ( 61 a - 1 to 61 a - 11 ) of the in-shaft communication passage ( 61 ) to be closed by the closing portion ( 94 d . 95 d ) sequentially change as the rotational angle position of the gate rotor ( 50 ) changes.
  • the in-shaft communication passage ( 61 ) whose inlet is closed by the closing portion ( 94 d , 95 d ) is blocked from the oil sump ( 94 c . 95 c ).
  • no lubricant flows into this in-shaft communication passage from the oil sump ( 94 c , 95 c ).
  • no lubricant flows into the oil sump ( 62 ) and the gate-side oil supply passage ( 63 ) which are sequentially connected to the in-shaft communication passage ( 61 ) whose inlet is closed.
  • the lubricant in the oil sump ( 94 c , 95 c ) flows into the in-shaft communication passage ( 61 ) whose inlet is not closed by the closing portion ( 94 d , 95 d ) and is opened in the oil sump ( 94 c , 95 c ), and also into the oil sump ( 62 ) and the gate-side oil supply passage ( 63 ) which are sequentially connected to the in-shaft communication passage ( 61 ). That is, the oil sump ( 94 c , 95 c ), which is the oil supply source supplying the lubricant to the gate-side oil supply passage ( 63 ), communicates with the gate-side oil supply passage ( 63 ).
  • each of the oil supply mechanisms ( 60 ) includes the in-shaft communication passages ( 61 ) and the oil sumps ( 62 ) which are individually connected to the gate-side oil supply passages ( 63 ).
  • the closing portion ( 94 d . 95 d ) is provided to close some of the inlets ( 61 a - 1 to 61 a - 11 ) of the in-shaft communication passages ( 11 ).
  • the inlets ( 61 a - 1 to 61 a - 11 ) of the inter-shaft communication passage ( 61 ) to be closed by the closing portion ( 94 d , 95 d ) are changed in accordance with the rotation of the gate rotor ( 50 ).
  • the gate-side oil supply passages ( 63 ) are in the supply state in which the gate-side oil supply passages ( 63 ) communicate with the oil sump ( 94 c , 95 c ) and supply the lubricant to the sliding surfaces ( 3 ).
  • the gate-side oil supply passages ( 63 ) are in the non-supply state in which the gate-side oil supply passages ( 63 ) are blocked from the oil sump ( 94 c , 95 c ) and supply no lubricant to the sliding surfaces ( 3 ).
  • the plurality of in-shaft communication passages ( 61 ), the plurality of oil sumps ( 62 ), and the closing portion ( 94 d , 95 d ) constitute a switching mechanism ( 6 ) for switching the gate-side oil supply passages ( 63 ) between the supply state and the non-supply state.
  • the gate-side oil supply passages ( 63 ) can be switched between the supply state in which the lubricant is supplied from the gate-side oil supply passages ( 63 ) to the sliding surfaces ( 3 ), and the non-supply state in which no lubricant is supplied from the gate-side oil supply passages ( 63 ) to the sliding surfaces ( 3 ).
  • the gate-side oil supply passages ( 63 ) can be switched to the non-supply state to stop the supply of the lubricant to the sliding surfaces ( 3 ) when the sliding surfaces do not slide and require no lubrication. Therefore, according to the second embodiment, the lubricant can be reliably supplied to the sliding surfaces ( 3 ) of the gate rotors ( 50 ), while reducing the supply amount of the lubricant.
  • the switching mechanism ( 6 ) is configured to switch the gate-side oil supply passage ( 63 ) formed in each gate ( 51 ) to the supply state when the front surface ( 51 c ) of the gate ( 51 ) faces the sealing surface ( 39 a ) of the cylindrical wall ( 30 ) and when the side surfaces ( 51 b , 51 c ) of the gate ( 51 ) face the inner surface ( 42 ) of the helical groove of the screw rotor ( 40 ), and to switch the gate-side oil supply passage ( 63 ) to the non-supply state when the gate ( 51 ) does not face the cylindrical wall ( 30 ) or the screw rotor ( 40 ).
  • the sliding surfaces ( 3 ) can be lubricated.
  • the gate ( 51 ) does not slide on the cylindrical wall ( 30 ) and the screw rotor ( 40 ) and forms a gap between the gate ( 51 ) and the cylindrical wall ( 30 ) and the screw rotor ( 40 ), the gap can be sealed.
  • the gate ( 51 ) does not face the cylindrical wall ( 30 ) or the screw rotor ( 40 )
  • no lubricant is supplied to the sliding surfaces ( 3 ) from the gate-side oil supply passages ( 63 ). This can reduce the supply amount of the lubricant.
  • the switching mechanism ( 6 ) switches the gate-side oil supply passages ( 63 ) to the supply state in which the gate-side oil supply passages ( 63 ) communicate with the oil sump ( 95 c , 94 c ) to supply the lubricant to the sliding surfaces ( 3 ).
  • the switching mechanism ( 6 ) switches the gate-side oil supply passages ( 63 ) to the non-supply state in which the gate-side oil supply passages ( 63 ) are blocked from the oil sump ( 95 c , 94 c ) and supply no lubricant to the sliding surfaces ( 3 ).
  • Such a simple configuration of the second embodiment makes it possible to automatically switch the gate-side oil supply passages ( 63 ) between the supply state and the non-supply state while the gate rotor ( 50 ) makes a single rotation.
  • the single-screw compressor ( 1 ) of the first embodiment is modified such that the oil supply mechanism ( 60 ) provided for each of the two gate rotors ( 50 ) is provided for the screw rotor ( 40 ) which meshes with the two gate rotors ( 50 ).
  • the single-screw compressor of the third embodiment has the oil supply mechanism ( 60 ) which is formed inside the screw rotor ( 40 ) and includes a plurality of axial passages ( 65 ) and a plurality of screw-side oil supply passages ( 66 ) (oil supply passages ( 5 )).
  • the plurality of axial passages ( 65 ) is formed at a position closer to the rotation axis than the bottom faces ( 42 c ) of the helical grooves ( 41 ) of the screw rotor ( 40 ).
  • six axial passages ( 65 ) are formed, and are arranged at equal intervals on an outer periphery of the rotation axis of the screw rotor ( 40 ).
  • Each axial passage ( 65 ) is formed by a hole extending in the direction of the rotation axis inside the screw rotor ( 40 ).
  • a discharge end (a right end in FIG. 2 ) of each axial passage ( 65 ) is opened at an end face (right end face in FIG. 2 ) of the screw rotor ( 40 ) on the discharge side.
  • each axial passage ( 65 ) does not reach an end face (a left end face in FIG. 2 ) of the screw rotor ( 40 ).
  • the discharge end of each axial passage ( 65 ) is opened in a space where the high pressure lubricant that has lubricated the bearing ( 36 ) of the bearing holder ( 35 ) for rotatably supporting the drive shaft ( 21 ), for example, is accumulated.
  • This configuration causes the high pressure lubricant to flow into the plurality of axial passages ( 65 ), and causes the axial passages ( 65 ) to serve as oil sumps in which the high pressure lubricant is accumulated.
  • the plurality of screw-side oil supply passages ( 66 ) is formed such that at least one screw-side oil supply passage ( 66 ) extends from an associated one of the axial passages ( 65 ) toward the outer periphery of the screw rotor ( 40 ).
  • Each of the screw-side oil supply passages ( 66 ) includes a body ( 66 a ) and a plurality of lateral branches ( 66 b ).
  • the body ( 66 a ) of each of the screw-side oil supply passages ( 66 ) is formed by a hole extending from an associated one of the axial passages ( 65 ) toward the outer periphery of the screw rotor ( 40 ).
  • the body ( 66 a ) of the screw-side oil supply passage ( 66 ) extends to an outer peripheral surface ( 43 ) which helically extends between the helical grooves ( 41 ) of the screw rotor ( 40 ), and is opened at the outer peripheral surface ( 43 ).
  • the body ( 66 a ) of the screw-side oil supply passage ( 66 ) is connected to an outer peripheral oil supply port ( 66 c ) which is an oil supply port ( 4 ) opened at the outer peripheral surface ( 43 ) of the screw rotor ( 40 ).
  • the lateral branches ( 66 b ) are formed by holes extending from the body ( 66 a ) toward the lateral faces ( 42 a . 42 b ) of the helical groove ( 41 ), and are connected to groove's lateral oil supply ports ( 66 d ) (in-groove oil supply ports), which are the oil supply ports ( 4 ) opened at the lateral faces ( 42 a , 42 b ) of the helical grooves ( 41 ).
  • two lateral branches ( 66 b ) are connected to a front portion and rear portion in the rotation direction of the body ( 66 a ) of each of the screw-side oil supply passages ( 66 ).
  • At least two groove's lateral oil supply ports ( 66 d ) are opened at the front lateral face ( 42 a ) of the inner surface ( 42 ) of the helical groove ( 41 ) of the screw rotor ( 40 ) in the rotation direction, and two groove's lateral oil supply ports ( 66 d ) are opened at the rear lateral face ( 42 b ).
  • the diameter of each of the groove's lateral oil supply ports ( 66 d ) and lateral branches ( 66 b ) is determined so that the lubricant flows in such an amount that allows an oil film to be formed on the lateral faces ( 42 a . 42 b ) of the helical groove ( 41 ) of the screw rotor ( 40 ), and that the lubricant is kept from scattering in the shape of droplets.
  • the number of groove's lateral oil supply ports ( 66 d ) and lateral branches ( 66 b ) is not limited to two, but may be less than two, or more than two.
  • the diameter is changed in accordance with the number so that the lubricant flows in such an amount that allows an oil film to be formed on the lateral faces ( 42 a , 42 b ) of the helical groove ( 41 ) of the screw rotor ( 40 ), and that the lubricant is kept from scattering in the shape of droplets.
  • each of the screw-side oil supply passages ( 66 ) is connected to the groove's lateral oil supply ports ( 66 d ) opened at the lateral faces ( 42 a , 42 b ) of the helical groove ( 41 ) of the screw rotor ( 40 ).
  • the screw-side oil supply passages ( 66 ) are positioned such that the groove's lateral oil supply ports ( 66 d ) are opened in the compression chamber ( 23 ) during the suction phase.
  • the screw-side oil supply passages ( 66 ) may be positioned such that the groove's lateral oil supply ports ( 66 d ) are opened in the compression chamber ( 23 ) during the suction phase, and also in the compression chamber ( 23 ) during the compression phase and the discharge phase.
  • the axial passages ( 65 ) and the screw-side oil supply passages ( 66 ) form a plurality of lubricant passages, each of which is branched to have two or more outlets.
  • Each of the lubricant passages has an inlet which is opened in a space where the high pressure lubricant that has lubricated the bearing ( 36 ), for example, is accumulated, and an outlet which is opened at the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) and the lateral faces ( 42 a . 42 b ) of the groove.
  • the high pressure lubricant near the inlet enters the lubricant passage, flows toward the outlet, and then flows to the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) and the lateral faces ( 42 a , 42 b ) of the helical groove ( 41 ).
  • the oil supply mechanism ( 60 ) formed in the screw rotor ( 40 ) supplies the lubricant to the sliding surfaces ( 3 ) of the two gate rotors ( 50 ) and the screw rotor ( 40 ).
  • the pressure difference between the inlets and outlets of the lubricant passage formed by the axial passage ( 65 ) and the screw-side oil supply passage ( 66 ) causes the high pressure lubricant that has lubricated the bearing ( 36 ) and has been accumulated in a predetermined space to enter the lubricant passage, and flow toward the outlets.
  • the high pressure lubricant flows into the axial passages ( 65 ) serving as the oil sumps, flows into the plurality of screw-side oil supply passages ( 66 ) extending from the axial passages ( 65 ) toward the outer periphery by the effect of the driving force derived from the pressure difference described above and the centrifugal force generated by the rotation of the screw rotor ( 40 ), and then flows outward in the screw-side oil supply passages ( 66 ) (see FIG. 15 ).
  • the lubricant flowing through the screw-side oil supply passages ( 66 ) flows from the outer peripheral oil supply ports ( 66 c ) to the outer peripheral surface ( 43 ) of the screw rotor ( 40 ), and also flows from the groove's lateral oil supply ports ( 66 d ) to the lateral faces ( 42 a , 42 b ) of the helical grooves ( 41 ) of the screw rotor ( 40 ).
  • the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) provided with the helical grooves ( 41 ) slides on the inner peripheral surface ( 30 a ) of the cylindrical wall ( 30 ) covering the outer periphery of the screw rotor ( 40 ).
  • lubrication is required to keep the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) and the inner peripheral surface ( 30 a ) of the cylindrical wall ( 30 ) from seizing.
  • the gap needs to be sealed so that the high pressure fluid does not leak to the low pressure side.
  • the screw-side oil supply passages ( 66 ) are formed in the screw rotor ( 40 ), and are connected to the outer peripheral oil supply ports ( 66 c ) opened at the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) which slides on the cylindrical wall ( 30 ).
  • the lubricant in the screw-side oil supply passages ( 66 ) flows from the outer peripheral oil supply ports ( 66 c ) to the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) which slides on the inner peripheral surface ( 30 a ) of the cylindrical wall ( 30 ), thereby lubricating the outer peripheral surface ( 43 ), or sealing the gap, if any, between the outer peripheral surface ( 43 ) and the inner peripheral surface ( 30 a ) of the cylindrical wall ( 30 ).
  • the outer peripheral oil supply ports ( 66 c ), which are the oil supply ports ( 4 ), are opened at the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) that rotates. Therefore, the lubricant that has flowed from the outer peripheral oil supply ports ( 66 c ) is rapidly spread over the rotating screw rotor ( 40 ), and is quickly supplied to the sliding surfaces ( 3 ) other than the outer peripheral surface ( 43 ) at which the outer peripheral oil supply ports ( 66 c ) are formed.
  • the screw rotor ( 40 ) and the gate rotors ( 50 ) mesh with each other and rotate together, the lubricant supplied to the screw rotor ( 40 ) is rapidly spread to the gate rotors ( 50 ), and is quickly supplied to the sliding surfaces ( 3 ) of the gate rotors ( 50 ).
  • the screw-side oil supply passages ( 66 ) are formed in the screw rotor ( 40 ), and the oil supply passages ( 5 ) are connected to the groove's lateral oil supply ports ( 66 d ), which are the in-groove oil supply ports opened at the inner surface ( 42 ) of the helical groove ( 41 ) of the screw rotor ( 66 ).
  • the lubricant in the screw-side oil supply passages ( 66 ) flows from the groove's lateral oil supply ports ( 66 d ) to the lateral faces ( 42 a , 42 b ) of the helical grooves ( 41 ) which slide on the gate rotor ( 50 ), thereby lubricating the lateral faces ( 42 a , 42 b ), or sealing the gap, if any, between the lateral faces ( 42 a . 42 b ) and the gate rotor ( 50 ) sliding on the lateral faces.
  • the lubricant is directly supplied to the lateral faces ( 42 a , 42 b ), which are the sliding surfaces ( 3 ), from the groove's lateral oil supply ports ( 66 d ) opened at the lateral faces ( 42 a , 42 b ) of the helical grooves of the screw rotor ( 40 ).
  • the groove's lateral oil supply ports ( 66 d ), which are the oil supply ports ( 4 ), are opened at the lateral faces ( 42 a , 42 b ) of the helical grooves of the screw rotor ( 40 ) that rotates. Therefore, the lubricant which has flowed from the groove's lateral oil supply ports ( 66 d ) is rapidly spread over the rotating screw rotor ( 40 ) by the effect of the centrifugal force, and is quickly supplied to the sliding surfaces ( 3 ) other than the lateral faces ( 42 a , 42 b ) of the helical grooves.
  • the lubricant supplied to the lateral faces ( 42 a , 42 b ) of the helical groove of the screw rotor ( 40 ) also adheres to the gate rotors ( 50 ) which mesh with and rotate with the screw rotor ( 40 ), and is rapidly spread over the gate rotors ( 50 ) by the effect of the centrifugal force.
  • the lubricant is quickly supplied to the sliding surfaces ( 3 ) of the gate rotors ( 50 ).
  • the screw-side oil supply passages ( 66 ) serving as the oil supply passages ( 5 ) are formed in the screw rotor ( 40 ), which is at least one of the screw rotor ( 40 ) and the gate rotors ( 50 ) mesh with each other and rotate together, and the screw-side oil supply passages ( 66 ) are connected to the outer peripheral oil supply ports ( 66 c ) and the groove's lateral oil supply ports ( 66 d ), which are the oil supply ports ( 4 ) opened at the outer peripheral surface ( 43 ) and the groove's lateral faces ( 42 a . 42 b ).
  • the lubricant is directly supplied from the outer peripheral oil supply ports ( 66 c ) and the groove's lateral oil supply ports ( 66 d ) to the outer peripheral surface ( 43 ) and the lateral faces ( 42 a , 42 b ) of the helical grooves, which are the sliding surfaces ( 3 ).
  • the lubricant can be reliably supplied in a smaller amount to the outer peripheral surface ( 43 ) and the lateral faces ( 42 a , 42 b ), which are the sliding surfaces ( 3 ) of the screw rotor ( 40 ).
  • the outer peripheral oil supply ports ( 66 c ) and the groove's lateral oil supply ports ( 66 d ), which are the oil supply ports ( 4 ), are opened at the outer peripheral surface ( 43 ) and the lateral faces ( 42 a , 42 b ) of the helical grooves, which are the sliding surfaces ( 3 ) of the screw rotor ( 40 ) that rotates, so that the lubricant flows to the sliding surfaces ( 3 ) from these oil supply ports.
  • the lubricant that has flowed from the outer peripheral oil supply ports ( 66 c ) and the groove's lateral oil supply ports ( 66 d ) is rapidly spread over the rotating screw rotor ( 40 ), and can be quickly supplied to the sliding surfaces ( 3 ) other than the outer peripheral surface ( 43 ) and the lateral faces ( 42 a , 42 b ) of the helical grooves at both of which the oil supply ports ( 4 ) are formed.
  • the lubricant supplied to the screw rotor ( 40 ) is rapidly spread to the gate rotors ( 50 ), and can be quickly supplied to the sliding surfaces ( 3 ) of the gate rotors ( 50 ).
  • the efficiency of the compressor is not lowered because it is unnecessary to increase the power for the transport of the lubricant and the power for the rotation of the screw rotor ( 40 ), unlike the conventional configuration in which a large amount of lubricant is supplied.
  • Supplying the lubricant in a small amount to at least one of the sliding surface ( 3 ) of the screw rotor ( 40 ) or the sliding surface ( 3 ) of the gate rotor ( 50 ) makes it possible to lubricate the sliding surface ( 3 ) of each of the screw rotor ( 40 ) and the gate rotor ( 50 ), or to seal a gap, if any, between the sliding surface ( 3 ) and its counterpart sliding surface.
  • the sliding surfaces ( 3 ) of the screw rotor ( 40 ) and the gate rotor ( 50 ) can be kept from seizing, and the high pressure fluid can be blocked from leaking from the compression chamber, even if the supply amount of the lubricant is reduced. Therefore, in the third embodiment, the supply amount of the lubricant can be reduced without lowering the reliability of the screw compressor ( 1 ), which can improve the compressor efficiency.
  • the axial passages ( 65 ) serving as the oil sumps are formed at a position closer to the rotation axis of the screw rotor ( 40 ) than the bottom faces ( 42 c ) of the helical grooves ( 41 ), and base ends of the screw-side oil supply passages ( 66 ) are respectively connected to the axial passages ( 65 ). That is, the screw-side oil supply passages ( 66 ) extend from the axial passages ( 65 ) in the screw rotor ( 40 ) toward the outer periphery.
  • the screw rotor ( 40 ) rotates to generate the centrifugal force, which causes the lubricant to enter the screw-side oil supply passages ( 66 ) from the axial passages ( 65 ), flows toward the outer periphery of the screw rotor ( 40 ), and flows from the oil supply ports ( 4 ) (the outer peripheral oil supply ports ( 66 c ) and the groove's lateral oil supply ports ( 66 d )) to the sliding surfaces ( 3 ) of the screw rotor ( 40 ) (the outer peripheral surface ( 43 ) and lateral faces ( 42 a , 42 b ) of the helical grooves).
  • this simple configuration can supply the lubricant to the sliding surfaces ( 3 ) of the screw rotor ( 40 ) (the outer peripheral surface ( 43 ) and the lateral faces ( 42 a , 42 b ) of the helical grooves) by utilizing the centrifugal force generated by the rotation of the screw rotor ( 40 ).
  • the single-screw compressor provided in the refrigerant circuit to compress the refrigerant has been described.
  • a target to be compressed (fluid) is not limited to the refrigerant, and the compressor is not limited to the single-screw compressor.
  • the compressor may be a twin screw compressor including a male rotor and a female rotor, or a compressor including female rotors provided on both sides of a male rotor.
  • the front oil supply ports ( 63 c ) that have been formed in the first and second embodiments may not be formed.
  • the lateral oil supply ports ( 63 b ) may be omitted, and the gate-side oil supply passages ( 63 ) may be connected only to the front oil supply ports ( 63 c ).
  • the lateral oil supply ports ( 63 b ) of each of the gate-side oil supply passages ( 63 ) are opened at the side surfaces ( 51 a , 51 b ) of the gate ( 51 ) on the front and rear sides in the direction of rotation of the gate ( 51 ).
  • the lateral oil supply ports ( 63 b ) may be opened at least at the rear side surface ( 51 b ) of the gate ( 51 ), and no oil supply port may be opened at the front side surface ( 51 b ) of the gate ( 51 ).
  • the rear side surface ( 51 b ) in the rotation direction of the gate ( 51 ) is the sliding surface ( 3 ) which reliably slides on the screw rotor ( 40 ) and is pressed by the screw rotor ( 40 ), and therefore, is probably worn through the sliding movement.
  • the lateral oil supply ports ( 63 b ) opened at the rear side surface ( 51 b ) cause the lubricant to be reliably supplied between the rear side surface ( 51 b ) and the lateral face ( 42 a , 42 b ) of the helical groove ( 41 ). This can protect the gate ( 51 ) and the screw rotor ( 40 ) from the sliding wear.
  • the groove's lateral oil supply ports ( 66 d ) of the screw-side oil supply passages ( 66 ) are opened at both lateral faces ( 42 a , 42 b ) of each of the helical grooves ( 41 ) of the screw rotor ( 40 ) on the front and rear sides in the rotation direction of the screw rotor.
  • the groove's lateral oil supply ports ( 66 d ) may be opened at least at the lateral face ( 42 b ) on the rear side of the helical groove ( 41 ) in the rotation direction, and no oil supply port may be opened at the lateral face ( 42 a ) on the front side of the helical groove ( 41 ) in the rotation direction.
  • the rear lateral face ( 42 b ) of the helical groove ( 41 ) in the rotation direction is the sliding surface ( 3 ) which reliably slides on the gate ( 51 ) of the gate rotor ( 50 ) and presses the gate ( 51 ) of the gate rotor ( 50 ), and therefore, is probably worn through the sliding movement.
  • the groove's lateral oil supply ports ( 66 d ) opened at the rear lateral face ( 42 b ) of the helical groove ( 41 ) cause the lubricant to be reliably supplied between the rear lateral face ( 42 b ) of the helical groove ( 41 ) and the gate ( 51 ) of the gate rotor ( 50 ). This can protect the gate ( 51 ) of the gate rotor ( 50 ) and the screw rotor ( 40 ) from the sliding wear.
  • four lateral oil supply ports ( 63 b ) are opened at each of the side surfaces ( 51 a , 51 b ) of the gate ( 51 ) at substantially equal intervals from the base end to distal end of the gate ( 51 ).
  • the at least one lateral oil supply port ( 63 b ) opened at a position closer to the base end of the gate ( 51 ) than the center thereof in the radial direction makes it possible to supply the lubricant to the base end of the side surface ( 51 a , 51 b ) of the gate ( 51 ), and to easily spread the lubricant toward the distal end of the side surface ( 51 a , 51 b ) of the gate ( 51 ) by utilizing the centrifugal force.
  • This configuration can minimize the number of the lateral oil supply ports ( 63 b ), and can further reduce the supply amount of the lubricant.
  • two groove's lateral oil supply ports ( 66 d ) are opened at each of the lateral faces ( 42 a . 42 b ) of the helical grooves ( 41 ) of the screw rotor ( 40 ).
  • the two groove's lateral oil supply ports ( 66 d ) are not always necessary, and at least one groove's lateral oil supply port may be formed at each lateral face ( 42 a , 42 b ) of the helical groove ( 41 ) at a position closer to the bottom face ( 42 c ) of the helical groove ( 41 ) than to the outer peripheral surface ( 43 ) of the screw rotor ( 40 ).
  • the at least one groove's lateral oil supply port ( 66 d ) opened at the lateral face ( 42 a , 42 b ) of the helical groove ( 41 ) of the screw rotor ( 40 ) at a position closer to the bottom face ( 42 c ) of the helical groove ( 41 ) than to the outer peripheral surface ( 43 ) makes it possible to supply the lubricant to a portion of the lateral face ( 42 a ) of the helical groove ( 41 ) closer to the rotation axis, and to easily spread the lubricant to a portion of the lateral face ( 42 a , 42 b ) of the helical groove ( 41 ) closer to the outer peripheral surface ( 43 ) by utilizing the centrifugal force.
  • This configuration can minimize the number of the groove's lateral oil supply ports ( 66 d ), and can further reduce the supply amount of the lubricant.
  • the oil supply mechanism ( 60 ) having the gate-side oil supply passage ( 63 ) has been provided in each of the two gate rotors ( 50 ).
  • the oil supply mechanism ( 60 ) may be provided in only one of the gate rotors ( 50 ).
  • the oil supply mechanism ( 60 ) provided in one of the gate rotors ( 50 ) supplies the lubricant to the sliding surfaces ( 3 ) of the gate rotor ( 50 ) and the screw rotor ( 40 ), the lubricant adheres to the lateral faces ( 42 a , 42 b ) of the helical grooves ( 41 ) of the screw rotor ( 40 ).
  • the lubricant can be left in the helical grooves ( 41 ) to lubricate the sliding surfaces ( 3 ) of the other gate rotor ( 50 ) and the screw rotor ( 40 ), and to seal the gap between the sliding surfaces ( 3 ).
  • the gate-side oil supply passages ( 63 ) of the oil supply mechanism ( 60 ) are formed in all the gates ( 51 ) of the gate rotor ( 50 ).
  • the gate-side oil supply passage ( 63 ) may be formed in at least one of the gates ( 51 ), and more preferably, may be formed in the same number as the number of helical grooves ( 41 ) in the screw rotor ( 40 ) (six in the above-described embodiments) in the gates ( 51 ) adjacent to each other.
  • the amount of lubricant supplied from the gate-side oil supply passages ( 63 ) to the sliding surfaces ( 3 ) of the gate rotor ( 50 ) and the screw rotor ( 40 ) is controlled by adjusting the number and diameter of the lateral oil supply ports ( 63 b ), the sliding surfaces ( 3 ) of the gate rotor ( 50 ) and the screw rotor ( 40 ) can be protected from the seizing even if the gate-side oil supply passage ( 63 ) is not formed in every gate ( 51 ).
  • the right oil supply mechanism ( 60 ) in FIG. 3 has the in-shaft communication passage ( 61 ) formed inside the front shaft portion ( 58 a ), and the left oil supply mechanism ( 60 ) has the in-shaft communication passage ( 61 ) formed inside the rear shaft portion ( 58 b ).
  • the position of the in-shaft communication passage ( 61 ) is not limited thereto.
  • the right oil supply mechanism ( 3 ) in FIG. 3 may have the in-shaft communication passage ( 61 ) formed inside the rear shaft portion ( 58 b ), and the left oil supply mechanism ( 60 ) may have the in-shaft communication passage ( 61 ) formed inside the front shaft portion ( 58 a ).
  • both of the oil supply mechanisms ( 60 ) may have the in-shaft communication passage ( 61 ) formed inside the front shaft portion ( 58 a ) or the rear shaft portion ( 58 b ).
  • the screw-side oil supply passages ( 66 ) are connected to the outer peripheral oil supply ports ( 66 c ) opened at the outer peripheral surface ( 43 ) of the screw rotor ( 40 ) and the groove's lateral oil supply ports ( 66 d ) opened at the lateral faces ( 42 a . 42 b ) of the helical grooves ( 41 ).
  • the screw-side oil supply passages ( 66 ) are not limited to those connected to the outer peripheral oil supply ports ( 66 c ) and the groove's lateral oil supply ports ( 66 d ).
  • the screw-side oil supply passages ( 66 ) may be connected to bottom oil supply ports which are opened at the bottom faces ( 42 c ) of the helical grooves ( 41 ) of the screw rotor ( 40 ).
  • the screw-side oil supply passages ( 66 ) may be connected only to the outer peripheral oil supply ports ( 66 c ) or the groove's lateral oil supply ports ( 66 d ).
  • the switching mechanism ( 6 ) of the second embodiment is not limited to have the above-described configuration, and may be configured in any way as long as the gate-side oil supply passages ( 63 ) can be switched between the supply state and the non-supply state. Further, the switching mechanism ( 6 ) of the second embodiment can be applied to the oil supply mechanism ( 60 ) formed in the screw rotor ( 40 ) as described in the third embodiment. In this case, a closing portion as described in the second embodiment may be provided in a space in which the discharge ends of the plurality of axial passages ( 65 ) are opened and the high pressure lubricant is accumulated.
  • the present invention is useful for a screw compressor.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
US16/484,796 2017-02-09 2018-02-09 Screw compressor Abandoned US20200003211A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2017021955 2017-02-09
JP2017-021955 2017-02-09
PCT/JP2018/004747 WO2018147452A1 (fr) 2017-02-09 2018-02-09 Compresseur à vis

Publications (1)

Publication Number Publication Date
US20200003211A1 true US20200003211A1 (en) 2020-01-02

Family

ID=63107207

Family Applications (1)

Application Number Title Priority Date Filing Date
US16/484,796 Abandoned US20200003211A1 (en) 2017-02-09 2018-02-09 Screw compressor

Country Status (4)

Country Link
US (1) US20200003211A1 (fr)
EP (1) EP3564532B1 (fr)
CN (1) CN110446857B (fr)
WO (1) WO2018147452A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11300124B2 (en) * 2017-03-21 2022-04-12 Daikin Industries, Ltd. Single-screw compressor with a gap adjuster mechanism

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116608129B (zh) * 2023-07-19 2023-09-12 天津乐科节能科技有限公司 一种单螺杆压缩机啮合副的喷气结构

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3736079A (en) * 1972-03-29 1973-05-29 Ford Motor Co Lubricating oil flow control for a rotary compressor

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1403614A1 (de) * 1960-06-22 1968-11-28 Fernand Zimmern Rotationsverdichter fuer hohe Leistungen und hohen Druck
JPS50110109A (fr) * 1974-02-08 1975-08-29
JPS5670186U (fr) * 1979-11-02 1981-06-10
SU1432270A2 (ru) * 1986-10-24 1988-10-23 Ленинградский технологический институт холодильной промышленности Однороторна винтова машина
FR2624215B1 (fr) * 1987-12-03 1990-05-11 Zimmern Bernard Pignons flottants pour machine a vis haute pression
WO1995018945A1 (fr) * 1994-01-10 1995-07-13 Fresco Anthony N Compresseurs a vis rotative pour refroidissement et etancheite
JP2008127990A (ja) * 2006-11-16 2008-06-05 Hitachi Industrial Equipment Systems Co Ltd スクリュー圧縮機
JP4518206B2 (ja) * 2007-12-28 2010-08-04 ダイキン工業株式会社 シングルスクリュー圧縮機
EP2246571A4 (fr) 2008-01-23 2014-11-26 Daikin Ind Ltd Compresseur à vis
JP2017015054A (ja) * 2015-07-06 2017-01-19 ダイキン工業株式会社 シングルスクリュー圧縮機
CN105179236B (zh) * 2015-07-24 2017-05-24 宝鸡市博磊化工机械有限公司 一种高效耐用单螺杆压缩机

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3736079A (en) * 1972-03-29 1973-05-29 Ford Motor Co Lubricating oil flow control for a rotary compressor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11300124B2 (en) * 2017-03-21 2022-04-12 Daikin Industries, Ltd. Single-screw compressor with a gap adjuster mechanism

Also Published As

Publication number Publication date
EP3564532A4 (fr) 2020-07-01
WO2018147452A1 (fr) 2018-08-16
EP3564532B1 (fr) 2024-05-01
CN110446857B (zh) 2021-12-14
CN110446857A (zh) 2019-11-12
EP3564532A1 (fr) 2019-11-06

Similar Documents

Publication Publication Date Title
JP5765379B2 (ja) スクロール圧縮機
US10527041B2 (en) Compressor having oil recovery means
US7713040B2 (en) Rotor shaft sealing method and structure of oil-free rotary compressor
WO2014041680A1 (fr) Système de compresseur à vis refroidi à l'huile et compresseur à vis refroidi à l'huile
US9869315B2 (en) Scroll compressor having capacity varying valves
US10844856B2 (en) Scroll compressor
JP5880513B2 (ja) 圧縮機
CN115244302B (zh) 螺杆压缩机及制冷装置
US20200003211A1 (en) Screw compressor
US6755632B1 (en) Scroll-type compressor having an oil communication path in the fixed scroll
CN107893758B (zh) 涡旋压缩机及具有其的空调器
EP1772627B1 (fr) Système d'étanchéité pour compresseur
JPH073228B2 (ja) スクロ−ル気体圧縮機
WO2022209582A1 (fr) Compresseur à vis et congélateur
CN101128647A (zh) 压缩机的卸载阀
WO2018117276A1 (fr) Compresseur à vis
US3250459A (en) Gear-rotor motor-compressor
CN213981182U (zh) 动涡旋组件及包括其的涡旋压缩机
CN113167278B (zh) 螺杆压缩机
JP2022502604A (ja) コンプレッサー
JPH025919B2 (fr)
JP2006037795A (ja) 容量可変型気体圧縮機
JP2014074367A (ja) スクリュ圧縮機
JPH073230B2 (ja) スクロ−ル気体圧縮機
JP2006291763A (ja) スクロール圧縮機

Legal Events

Date Code Title Description
AS Assignment

Owner name: DAIKIN INDUSTRIES, LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MIYAMURA, HARUNORI;REEL/FRAME:050006/0726

Effective date: 20180427

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION COUNTED, NOT YET MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER

STPP Information on status: patent application and granting procedure in general

Free format text: FINAL REJECTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: ADVISORY ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION