Motor-driven roots pump

Patent metadata

Field	Value
Publication number	US-10738778-B2
Application number	US-201916250550-A
Country	US
Kind code	B2
Filing date	Jan 17, 2019
Priority date	Jan 22, 2018
Publication date	Aug 11, 2020
Grant date	Aug 11, 2020

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.

First claim

The invention claimed is:

1. A motor-driven Roots pump comprising:
a housing;
a drive shaft and a driven shaft that are rotationally supported by the housing in a state arranged parallel to each other in the housing;
a drive gear that is fixed to the drive shaft;
a driven gear that is fixed to the driven shaft and meshed with the drive gear;
a drive rotor that is arranged on the drive shaft;
a driven rotor that is arranged on the driven shaft and meshed with the drive rotor;
an electric motor that rotates the drive shaft;
a motor chamber that is formed in the housing and accommodates the electric motor;
a gear chamber that is formed in the housing, accommodates the drive gear and the driven gear, and retains oil in a sealed manner; and
a rotor chamber that is formed in the housing and accommodates the drive rotor and the driven rotor, wherein
the motor chamber, the gear chamber, and the rotor chamber are arranged in this order along a rotational axis of the drive shaft,
the housing includes
a first partition wall that separates the gear chamber from the motor chamber in a direction of the rotational axis of the drive shaft,
a second partition wall that separates the gear chamber from the rotor chamber in the direction of the rotational axis of the drive shaft,
an outer wall that separates the rotor chamber from the exterior in the direction of the rotational axis of the drive shaft, and
a rotor-chamber wall that has a shape of a circumferential wall that extends along the rotational axis of the drive shaft and defines the rotor chamber together with the second partition wall and the outer wall, wherein

the rotor-chamber wall has, at positions opposed to each other with the rotor chamber in between, a suction port and a discharge port through which the rotor chamber communicates with the exterior,
the first partition wall has a first seal accommodating recess that accommodates an annular first seal member for sealing the gear chamber and the motor chamber from each other, with the drive shaft extending through the first seal member,
the second partition wall has
a second seal accommodating recess that accommodates an annular second seal member for sealing the gear chamber and the rotor chamber from each other, with the drive shaft extending through the second seal member, and
a third seal accommodating recess that accommodates an annular third seal for sealing the gear chamber and the rotor chamber from each other, with the driven shaft extending through the third seal member,

a side on which the discharge port is located with respect to a plane that includes both the rotational axis of the drive shaft and the rotational axis of the driven shaft is a first side,
an end surface of the first partition wall that defines the gear chamber has a first recess on the first side,
an end surface of the second partition wall that defines the gear chamber has a second recess that is opposed to the first recess in the direction of the rotational axis,
as viewed in the direction of the rotational axis of the drive shaft, the first recess and the second recess at least partially overlap with each other in a range between the drive gear and the driven gear,
the first partition wall has a first oil supply passage that is configured to supply the oil from the first recess to the first seal accommodating recess, and
the second partition wall has
a second oil supply passage that is configured to supply oil from the second recess to the second seal accommodating recess, and
a third oil supply passage that is configured to supply oil from the second recess to the third seal accommodating recess.

2. The motor-driven Roots pump according to claim 1 , wherein, as viewed in the direction of the rotational axis of the drive shaft and in the range between the drive gear and the driven gear, a minimum distance from the first recess to the plane that includes both the rotational axis of the drive shaft and the rotational axis of the driven shaft is equal to a minimum distance from the second recess to the plane.

3. The motor-driven Roots pump according to claim 1 , wherein
a guide portion is arranged in the gear chamber and located between the first recess and the second recess in the direction of the rotational axis, and
the guide portion is configured to guide oil toward the first recess and the second recess.

4. The motor-driven Roots pump according to claim 3 , wherein the guide portion is located on a side on which the discharge port is located with respect to a meshing portion in which the drive gear and the driven gear are meshed with each other.

5. The motor-driven Roots pump according to claim 3 , wherein the guide portion is a drain plug.

6. The motor-driven Roots pump according to claim 3 , wherein
the guide portion has two first guide surfaces that are configured to guide oil after the oil is stirred up by the drive gear and two second guide surfaces that are configured to guide oil after the oil is stirred up by the driven gear, and
when a plane that includes both the rotational axis of the drive shaft and the rotational axis of the driven shaft is viewed from above, the two first guide surfaces extend to become more spaced from each other from the drive gear toward the driven gear and the two second guide surfaces extend to become more spaced from each other from the driven gear toward the drive gear.

7. The motor-driven Roots pump according to claim 1 , comprising a separator portion that is arranged between the first recess and the second recess in the direction of the rotational axis in the gear chamber and on a side on which the discharge port is located with respect to a meshing portion in which the drive gear and the driven gear are meshed with each other, wherein
an inner circumferential surface of the housing that defines the gear chamber has a first-side section that is located on the first side, and
the separator portion has a spaced surface that is spaced from the first-side section.

Assignees

• Toyota Jidoshokki Kk

Inventors

• Hirano Takayuki
• Masaki Daisuke
• Kashiwa Shintaro
• Takani Naoki

Classifications

• F04C15/0061

  Means for transmitting movement from the prime mover to driven parts of the pump, e.g. clutches, couplings, transmissions · CPC title

• F04C29/028

  Means for improving or restricting lubricant flow · CPC title

• F04C15/0088

  Lubrication (of machines or engines in general F01M) · CPC title

• F04C18/084

  Toothed wheels · CPC title

• F04C15/0038

  Shaft sealings specially adapted for rotary-piston machines or pumps · CPC title