# US 2009/0288641 A1 · Link type variable stroke engine

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- Number: US 2009/0288641 A1
- Document ID: US20090288641A1
- Status: Published application
- Kind: A1
- Application number: 12/464,499
- Filed: 2009-05-12
- Published: 2009-11-26
- Earliest claimed: 2008-05-13
- Assignees: Honda Motor Co., Ltd.
- Inventors: Sei Watanabe; Shohei Kono; Gaku Naoe
- Web page: https://patentgrep.com/patent/US20090288641A1

## CPC

- F16F 15/26: of crankshaft systems using solid masses, other than the ordinary pistons, moving with the system {, i.e. masses connected through a kinematic mechanism or gear system (F16F15/226 takes precedence)}
- F02B 75/048: {by means of a variable crank stroke length}
- F01L 1/026: {Gear drive}
- F01L 1/146: {Push-rods}
- F01L 1/183: {of the boat type}
- F01L 1/205: {by means of shims or the like}
- F01L 2001/054: {Camshafts in cylinder block}
- F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES

## Abstract

In a link type variable stroke engine in which a piston, a crankshaft and an eccentric shaft are linked by a linking mechanism, a counterweight part which is provided so that in a projection view on a plane orthogonal to an axis of a rotary shaft, a center of gravity of the counterweight part is located on an opposite side of the axis of the rotary shaft from an axis of the eccentric shaft rotates together with the rotary shaft. Accordingly, it is possible to effectively suppress and lessen half-order inertial exciting force occurring at the eccentric shaft.

## Claims

### Claim 1

A link type variable stroke engine in which,
in a crankcase of an engine main body,
a crankshaft is rotatably supported, and
a rotary shaft is rotatably supported so that power is transmitted at a speed reduction ratio of 1/2 from the crankshaft, the rotary shaft having an axis parallel with the crankshaft and being provided with an eccentric shaft at an eccentric position, and
a piston, slidably fitted to a cylinder block of the engine main body, the crankshaft and the eccentric shaft are linked by a linking mechanism, the linking mechanism including: a main connecting rod coupled, at one end, with the piston by using a piston pin; a sub connecting rod rotatably coupled with a crank pin of the crankshaft and rotatably coupled with the other end of the main connecting rod by using a connecting rod pin; and a swing rod rotatably coupled, at one end, with the sub connecting rod by using a swing pin at a position displaced from a position coupled with the main connecting rod and rotatably coupled, at the other end, with the eccentric shaft,
wherein a counterweight part is provided so that in a projection view on a plane orthogonal to the axis of the rotary shaft, a center of gravity of the counterweight part is located on an opposite side of the axis of the rotary shaft from an axis of the eccentric shaft, and rotates together with the rotary shaft.

### Claim 2 (depends on 1)

The link type variable stroke engine according to claim 1, wherein the counterweight part is provided to the eccentric shaft.

### Claim 3 (depends on 1)

The link type variable stroke engine according to claim 1, wherein the counterweight part is provided to a driven ring which constitutes a part of a timing transmitting mechanism provided between the crankshaft and the rotary shaft and which is fixed to the rotary shaft.