# US 10,865,789 B2 · Scavenge pump with improved lubrication

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- Number: US 10,865,789 B2
- Document ID: US10865789B2
- Status: Granted
- Kind: B2
- Application number: 16/142,838
- Filed: 2018-09-26
- Published: 2019-04-25
- Granted: 2020-12-15
- Earliest claimed: 2017-10-20
- Assignees: Yamada Manufacturing Co., Ltd.
- Applicants: Yamada Manufacturing Co., Ltd.
- Inventors: Atsushi Kaneko; Kei Hosoya
- Web page: https://patentgrep.com/patent/US10865789B2

## CPC

- F04C 15/0088: {Lubrication (of machines or engines in general F01M)}
- F01M 1/02: using lubricating pumps (pumps in general F04; lubricating pumps per se F16N)
- F04C 2/086: {Carter}
- F04C 2/102: {the two members rotating simultaneously around their respective axes}
- F01M 2001/0238: {Rotary pumps}
- F04C 2240/60: Shafts
- F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F01M: LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING

## Abstract

A scavenge pump includes: a pump housing including a housing body and a cover member, the housing body having a rotor chamber in which an inlet port, an outlet port, and a bearing hole formed by shaft holes with varying diameters with a stepped surface therebetween are provided; an outer rotor housed in the rotor chamber and having inner teeth; an inner rotor having outer teeth and a shaft support hole; and a drive shaft inserted or fixedly attached to the shaft support hole. The bearing hole includes a stepped inner circumferential part having a larger diameter than that of the drive shaft at an open peripheral edge on one side facing the rotor chamber, and a groove that extends through between a point close to a trailing end of the outlet port and the stepped inner circumferential part is formed.

## Claims

### Claim 1

A scavenge pump, comprising:
a pump housing including a housing body and a cover member, the housing body having a rotor chamber in which an inlet port, an outlet port, and a bearing hole formed by shaft holes with varying diameters with a stepped surface therebetween are provided;
an outer rotor housed in the rotor chamber and having inner teeth;
an inner rotor having outer teeth and a shaft support hole; and
a drive shaft inserted or fixedly attached to the shaft support hole of the inner rotor, wherein
the bearing hole includes a stepped inner circumferential part having a larger diameter than that of the drive shaft at an open peripheral edge on one side facing the rotor chamber, and a groove that extends between a point close to a trailing end of the outlet port and the stepped inner circumferential part is formed, and
wherein the inner rotor includes a cylindrical part that surrounds the shaft support hole, the cylindrical shaft part being fitted in or axially supported by the stepped inner circumferential part.

### Claim 2 (depends on 1)

The scavenge pump according to claim 1, wherein the drive shaft is inserted or axially supported in the bearing hole.

### Claim 3 (depends on 1)

The scavenge pump according to claim 1, wherein the stepped inner circumferential part is formed only on the housing body of the pump housing.

### Claim 4 (depends on 1)

The scavenge pump according to claim 1, wherein the outlet port has a deepest point, which is positioned at the trailing end and on an inner circumferential surface on one side closer to the bearing hole, and a highest point on the inner circumferential surface, the deepest point being positioned lower than the highest point.

### Claim 5 (depends on 1)

The scavenge pump according to claim 1, wherein the groove is provided in plurality.