Abstract: A resin composition for cleaning molding machines that achieves both high cleaning power for the material mold-processed before cleaning and easy replacement to the material to be mold-processed after cleaning, improves stable raw material feedability, has metered purging suitability, and has improved workability by suppressing spurt and emission of fume from a molding machine during the cleaning process is provided. To achieve the object, the present disclosure is a resin composition for cleaning molding machines including a thermoplastic resin (A), a synthetic wax (B), and a polyolefin-based resin (C), wherein an absolute value of a difference between solubility parameters of (A) and (B) is 2.0 (cal/cm3)1/2 or more and 7.0 (cal/cm3)1/2 or less, a compounding amount of (C) is more than 0.1 mass % and less than 10 mass %, and a glass transition temperature of (C) is higher than ?150° C. and lower than 40° C.

Abstract: A roots pump comprising: a rotary shaft; a rotor having a hole-forming surface that forms an insertion hole, and a first bearing and a second bearing. Each of the first bearing and the second bearing includes an inner ring and an outer ring. The rotary shaft is press-fitted in the inner ring of the first bearing, and fitted in the inner ring of the second bearing with a clearance between the rotary shaft and the inner ring of the second bearing. An edge portion of the hole-forming surface adjacent to the first bearing serves as a press-fitting portion in which the rotary shaft is press-fitted, and at least an edge portion of the hole-forming surface adjacent to the second bearing serves as a clearance-fitting portion in which the rotary shaft is fitted with a clearance between the rotary shaft and the clearance-fitting portion.

Abstract: A roots pump comprising: a rotary shaft; a rotor having a hole-forming surface that forms an insertion hole, and a first bearing and a second bearing. Each of the first bearing and the second bearing includes an inner ring and an outer ring. The rotary shaft is press-fitted in the inner ring of the first bearing, and fitted in the inner ring of the second bearing with a clearance between the rotary shaft and the inner ring of the second bearing. An edge portion of the hole-forming surface adjacent to the first bearing serves as a press-fitting portion in which the rotary shaft is press-fitted, and at least an edge portion of the hole-forming surface adjacent to the second bearing serves as a clearance-fitting portion in which the rotary shaft is fitted with a clearance between the rotary shaft and the clearance-fitting portion.

Abstract: The present disclosure is directed to providing a resin composition that is excellent in shape retentionability and production stability, reduces die drool, and improves maintenance and management of production machines, and a cleaning method of a resin molding processing machine using the resin composition. The resin composition of the present disclosure contains at least (A) a polyethylene-based resin having a melting point of 121 to 140° C. and (B) an inorganic foaming agent. The mass ratio of the (A) component is 50 to 84 parts by mass and the mass ratio of the (B) component is 50 to 16 parts by mass when the total mass of the (A) component and the (B) component is taken as 100 parts by mass. The weight loss ratio measured using a TGA apparatus when heated from 25° C. to 200° C. under an inert gas atmosphere is 3.0 to 15 mass %.

Abstract: A roots pump includes a housing, a rotor chamber, a pair of rotary shafts, and a pair of rotors. The rotor chamber includes a rotor chamber peripheral surface facing a pair of distal end portions of each of the rotors. Each of the pair of the distal end portions includes: a pair of rotor peripheral surfaces facing the rotor chamber peripheral surface with a first radial clearance; and a distal end peripheral surface that is formed between the pair of the rotor peripheral surfaces in the rotational direction and faces the rotor chamber peripheral surface with a second radial clearance greater than the first radial clearance. A width of the rotor chamber peripheral surface facing the distal end peripheral surface in the rotational direction is greater than a sum of a pair of predetermined widths of the rotor chamber peripheral surface facing the pair of the rotor peripheral surfaces.

Abstract: An electric pump includes a housing that includes a gear chamber, a rotor chamber, and a motor chamber. The electric pump includes a first seal member, a second seal member, and a third seal member. The first seal member seals a space between the gear chamber and the rotor chamber. The second seal member seals the space between the gear chamber and the rotor chamber. The third seal member seals a space between the gear chamber and the motor chamber. The third seal member seals the space between the gear chamber and the motor chamber to a lesser extent than the first seal member and the second seal member seal the space between the gear chamber and the rotor chamber.

Abstract: A roots pump includes a housing, a rotor chamber, a pair of rotary shafts, and a pair of rotors. The rotor chamber includes a rotor chamber peripheral surface facing a pair of distal end portions of each of the rotors. Each of the pair of the distal end portions includes: a pair of rotor peripheral surfaces facing the rotor chamber peripheral surface with a first radial clearance; and a distal end peripheral surface that is formed between the pair of the rotor peripheral surfaces in the rotational direction and faces the rotor chamber peripheral surface with a second radial clearance greater than the first radial clearance. A width of the rotor chamber peripheral surface facing the distal end peripheral surface in the rotational direction is greater than a sum of a pair of predetermined widths of the rotor chamber peripheral surface facing the pair of the rotor peripheral surfaces.

Abstract: A motor-driven Roots pump includes a housing, a drive shaft and a driven shaft that have axial lines parallel with each other, and a gear chamber. The housing includes a first partition that has a first defining surface, a second partition having a second defining surface, and a relief recess. An addendum circle of the drive gear and an addendum circle of the driven gear intersect with each other at a first intersection point. A plane that includes both the axial lines is defined as an imaginary plane. The first intersection point is located on a side of the imaginary plane on which the drive gear and the driven gear start meshing with each other. An opening of the relief recess is opposed to the first intersection point and is arranged in a region on a side of the imaginary plane on which the first intersection point is located.

Abstract: An electric pump includes a housing that includes a gear chamber, a rotor chamber, and a motor chamber. The electric pump includes a first seal member, a second seal member, and a third seal member. The first seal member seals a space between the gear chamber and the rotor chamber. The second seal member seals the space between the gear chamber and the rotor chamber. The third seal member seals a space between the gear chamber and the motor chamber. The third seal member seals the space between the gear chamber and the motor chamber to a lesser extent than the first seal member and the second seal member seal the space between the gear chamber and the rotor chamber.

Abstract: A housing unit of a Roots pump includes a rotor housing, which includes a peripheral wall, and a cover member, which closes an opening of the rotor housing. At least one of a mating surface of the peripheral wall or a mating surface of the cover member includes an annular first groove accommodating a seal member. The rotor housing includes a bulging portion including a second groove. The seal member incudes first projections, which project from an annular seal body, and a second projection, which projects further radially inward from the seal body than the first projections. Each first projection includes a distal end that contacts a side surface on a radially inner side or on a radially outer side of the first groove. The second projection is arranged in the second groove to determine the position of the seal body in the first groove.

Abstract: A seal member includes pushing projections that project from a seal body toward at a groove inner-side circumferential surface and are arranged at intervals in a circumferential direction of the seal body. The pushing projections push the seal body against the groove inner-side circumferential surface and a groove outer-side circumferential surface between the groove inner-side circumferential surface and the groove outer-side circumferential surface. This reduces the gap between the groove outer-side circumferential surface and the seal member in the seal accommodating groove. Thus, salt water is unlikely to collect in the gap between the groove outer-side circumferential surface of the seal accommodating groove and the seal member. This improves the corrosion resistance of the housing and the seal member.

Abstract: A housing unit of a Roots pump includes a rotor housing, which includes a peripheral wall, and a cover member, which closes an opening of the rotor housing. At least one of a mating surface of the peripheral wall or a mating surface of the cover member includes an annular first groove accommodating a seal member. The rotor housing includes a bulging portion including a second groove. The seal member incudes first projections, which project from an annular seal body, and a second projection, which projects further radially inward from the seal body than the first projections. Each first projection includes a distal end that contacts a side surface on a radially inner side or on a radially outer side of the first groove. The second projection is arranged in the second groove to determine the position of the seal body in the first groove.

Abstract: A motor-driven Roots pump includes a housing, a drive shaft and a driven shaft that have axial lines parallel with each other, and a gear chamber. The housing includes a first partition that has a first defining surface, a second partition having a second defining surface, and a relief recess. An addendum circle of the drive gear and an addendum circle of the driven gear intersect with each other at a first intersection point. A plane that includes both the axial lines is defined as an imaginary plane. The first intersection point is located on a side of the imaginary plane on which the drive gear and the driven gear start meshing with each other. An opening of the relief recess is opposed to the first intersection point and is arranged in a region on a side of the imaginary plane on which the first intersection point is located.

Abstract: A rotor-chamber wall of a motor-driven Roots pump has a suction port and a discharge port. The side on which the discharge port is located with respect to a plane that includes both the rotational axis of a drive shaft and the rotational axis of a driven shaft is a first side. A first partition wall defines a gear chamber and has a first recess on the first side. A second partition wall defines the gear chamber and has a second recess. The first partition wall has a first oil supply passage that is configured to supply oil from the first recess to a first seal accommodating recess. The second partition wall has a second and a third oil supply passages. The second and the third oil supply passages are configured to supply oil from the second recess to a second and a third seal accommodating recesses, respectively.

Abstract: A seal member includes pushing projections that project from a seal body toward at a groove inner-side circumferential surface and are arranged at intervals in a circumferential direction of the seal body. The pushing projections push the seal body against the groove inner-side circumferential surface and a groove outer-side circumferential surface between the groove inner-side circumferential surface and the groove outer-side circumferential surface. This reduces the gap between the groove outer-side circumferential surface and the seal member in the seal accommodating groove. Thus, salt water is unlikely to collect in the gap between the groove outer-side circumferential surface of the seal accommodating groove and the seal member. This improves the corrosion resistance of the housing and the seal member.

Abstract: A rotor-chamber wall of a motor-driven Roots pump has a suction port and a discharge port. The side on which the discharge port is located with respect to a plane that includes both the rotational axis of a drive shaft and the rotational axis of a driven shaft is a first side. A first partition wall defines a gear chamber and has a first recess on the first side. A second partition wall defines the gear chamber and has a second recess. The first partition wall has a first oil supply passage that is configured to supply oil from the first recess to a first seal accommodating recess. The second partition wall has a second and a third oil supply passages. The second and the third oil supply passages are configured to supply oil from the second recess to a second and a third seal accommodating recesses, respectively.

Abstract: A hydrogen circulation pump for a fuel cell includes a housing, rotary shafts, and two-lobe rotors. Each of the rotors has a configuration defined by the profile defined by an arc having a radius R and extending from apex end to a first transition point, an involute curve extending from the first transition point to a second transition point, and an envelope curve formed continuously with the involute curve from the second transition point to the bottom end based on a basic circle having a radius r?. A distance between the apex ends of the lobe portions of each of the rotors is D. A distance between the axes of the pair of the rotary shafts is L. The radius R is set in {(?2)/16}?L<R<{(27?5?2)/56}L, and the radius r is set in L/(2?2)<r<0.3(?2)L, and the radius r? is set in ?/(4?2)L<r?<1.28?/(4?2)L, and the distance D is set in 2{L+?/(4?2)L}<D<2.032{L+?/(4?2)L}.

Abstract: An air compressor as a fluid compressor includes: a suction port and a delivery port provided at upper and lower portions, respectively, of a pump chamber; a suction passage in communication with the inside of the pump chamber via the suction port; a delivery passage in communication with the inside of the pump chamber via the delivery port; and a driving rotor and a driven rotor provided in the pump chamber. At least a part of the suction passage is located below the suction port.

Abstract: A heat-shrinkable laminate film includes layer (A) and layer (B) laminated via an interface having an interlayer strength of ?0.5 N/15 mm, in which layer (A) has at least a substrate layer containing a polypropylene-based resin, layer (B) has at least a seal layer containing a polyethylene-base resin, and any of the following is satisfied: (1) the difference in heat shrinkage rate between layer (A) and layer (B) is ?10% at 100° C., and the laminate film includes a gas barrier layer containing a saponified ethylene-vinyl alcohol copolymer and has an oxygen transmission rate of ?60 cc/m2·day·atm; and (2) the difference in heat shrinkage rate between layer (A) and layer (B) is ?20% at 100° C., and the heat-shrinkable laminate film includes a gas barrier layer containing an aromatic polyamide-based copolymer and has an oxygen transmission rate of ?60 cc/m2·day·atm.

Abstract: A heat-shrinkable laminate film includes layer (A) and layer (B) laminated via an interface having an interlayer strength of ?0.5 N/15 mm, in which layer (A) has at least a substrate layer containing a polypropylene-based resin, layer (B) has at least a seal layer containing a polyethylene-base resin, and any of the following is satisfied: (1) the difference in heat shrinkage rate between layer (A) and layer (B) is ?10% at 100° C., and the laminate film includes a gas barrier layer containing a saponified ethylene-vinyl alcohol copolymer and has an oxygen transmission rate of ?60 cc/m2·day·atm; and (2) the difference in heat shrinkage rate between layer (A) and layer (B) is ?20% at 100° C., and the heat-shrinkable laminate film includes a gas barrier layer containing an aromatic polyamide-based copolymer and has an oxygen transmission rate of ?60 cc/m2·day·atm.