# US 2014/0196447 A1 · Hydraulic circuit for transmissions

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2014/0196447 A1
- Document ID: US20140196447A1
- Status: Published application
- Kind: A1
- Application number: 14/233,336
- Filed: 2012-07-17
- Published: 2014-07-17
- Earliest claimed: 2011-07-27
- Assignees: Mikuni Corporation
- Inventors: Norio Takehana
- Web page: https://patentgrep.com/patent/US20140196447A1

## CPC

- F16H 57/0436: {Pumps}
- F04C 2/10: of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
- F04C 11/001: {of similar working principle}
- F04C 13/007: {Venting; Gas and vapour separation during pumping (preventing vapour lock in fuel pumps F02M37/20, in centrifugal pumps F04D9/00)}
- F16H 57/0446: {the supply forming part of the transmission control unit, e.g. for automatic transmissions}
- F04C 2210/206: Oil
- F16H 57/0489: {with endless flexible members, e.g. belt CVTs}
- F16H: GEARING
- F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS

## Abstract

The CVT 1 includes a part to be lubricated and a hydraulic control part for controlling transmission. The hydraulic circuit for transmissions includes a first hydraulic oil pathway for supplying oil from the pump apparatus to the hydraulic control part, and a second lubricating oil pathway for supplying oil containing an air bubble to the part to be lubricated. The pump apparatus includes a multi-stage trochoid pump and has an air bubble-containing oil discharging part for discharging the oil containing an air bubble to the first stage trochoid pump part. The air bubble-containing oil discharging part is connected to the second lubricating oil pathway. The second stage trochoid pump part increases pressure of the oil discharged from the first stage trochoid pump part, and discharges it from the high-pressure oil discharging part. The first hydraulic oil pathway is connected to the high-pressure oil discharging part.

## Claims

### Claim 1

A hydraulic circuit for transmissions comprising:
a hydraulic oil pathway configured to supply hydraulic oil to a hydraulic control part of a transmission, the hydraulic control part hydraulically controlling the transmission;
a lubricating oil pathway for supplying the oil to a part to be lubricated configured to be lubricated by the oil of the transmission;
a collecting part configured to collect the oil to be supplied to the hydraulic control part and the part to be lubricated; and
a pump apparatus configured to supply the oil from the collecting part to the hydraulic oil pathway and the lubricating oil pathway,
wherein the pump apparatus includes:
a low-pressure oil discharging unit having an air bubble-containing oil discharging part configured to separate an air bubble from the oil sucked from the collecting part and to discharge the oil containing an air bubble to the lubricating oil pathway, and a low-pressure oil discharging part configured to discharge the oil from which an air bubble has been separated; and
a high-pressure oil discharging unit having a high-pressure oil discharging part configured to increase pressure of the oil supplied from the low-pressure oil discharging part of the low-pressure oil discharging unit to have a higher pressure than the oil discharged from the low-pressure oil discharging part, and to discharge the oil to the hydraulic oil pathway.

### Claim 2 (depends on 1)

The hydraulic circuit for transmissions according to claim 1, wherein the low-pressure oil discharging unit is a trochoid pump having the air bubble-containing oil discharging part and the low-pressure oil discharging part.

### Claim 3 (depends on 1)

The hydraulic circuit for transmissions according to claim 1, wherein the high-pressure oil discharging unit is a multi-stage trochoid pump.

### Claim 4 (depends on 3)

The hydraulic circuit for transmissions according to claim 3,
wherein the pump apparatus includes the multi-stage trochoid pump,
the multi-stage trochoid pump is provided with the air bubble-containing oil discharging part configured to discharge the air bubble-containing oil at least in the first stage from an oil suction side, and
with the high-pressure oil discharging part configured to discharge oil in the final stage, the oil being increased in pressure by the oil, from which an air bubble has been separated, being fed from the first stage to a following stage in order, wherein
at least a stage to be the first stage of the multi-stage trochoid pump is the low-pressure oil discharging unit, and a stage after the first stage is the high-pressure oil discharging unit.