Kabushiki Kaisha Toyota Jidoshokki

Nok Corporation

Naoki Takani

Takayuki Hirano

Daisuke Masaki

Shintaro Kashiwa

Fumiya Shinoda

Yohei Miki

Takahiro Kato

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.

Motor-driven roots pump with smooth activation in low-temperature environment

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.

Roots pump having a seal member with first and second projections

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.

Fluid machine

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.

Growing community of inventors

Kariya, Japan

Naoki Takani