# US 10,767,740 B2 · Tensioner

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- Number: US 10,767,740 B2
- Document ID: US10767740B2
- Status: Granted
- Kind: B2
- Application number: 15/919,589
- Filed: 2018-03-13
- Published: 2018-09-27
- Granted: 2020-09-08
- Earliest claimed: 2017-03-21
- Assignees: Tsubakimoto Chain Co.
- Applicants: Tsubakimoto Chain Co.
- Inventors: Masanori Watanabe; Yuji Kurematsu
- Web page: https://patentgrep.com/patent/US10767740B2

## CPC

- F16H 7/0848: {with means for impeding reverse motion}
- F16H 2007/0812: {Fluid pressure}
- F16H 2007/0814: {with valves opening on surplus pressure}
- F16H 2007/0853: {Ratchets}
- F16H 2007/0859: {Check valves}
- F16H 2007/0872: {Sliding members}
- F16H 2007/0893: {Circular path}
- F16H 2007/0897: {External to internal direction}
- F16H: GEARING

## Abstract

To provide a tensioner capable of keeping oil pressure in an oil pressure chamber stable with a simple structure. The tensioner includes a pressure adjusting mechanism that adjusts oil pressure in the oil pressure chamber. The pressure adjusting mechanism includes a cylinder part, a piston unit set inside the cylinder part so as to be able to approach and separate from the oil pressure chamber, and a piston biasing unit. Between the cylinder part and the piston unit, a liquid tight condition is kept at any place between a position where the piston unit has moved closest to the oil pressure chamber and a position where the piston unit has moved closest to the adjustment space.

## Claims

### Claim 1

A tensioner comprising:
a plunger having a plunger hole that is open on a rear side; a housing having a plunger accommodating hole that is open on a front side and accommodates the plunger; a main biaser that is accommodated inside an oil pressure chamber and that is formed between the plunger and the plunger accommodating hole so as to expand and contract, and urging the plunger toward the front side; and a pressure adjusting mechanism adjusting oil pressure in the oil pressure chamber,
the pressure adjusting mechanism including a cylinder part, a piston unit set inside the cylinder part so as to be able to approach and separate from the oil pressure chamber and partitioning a space formed between the plunger and the housing into the oil pressure chamber and an adjustment space, and a piston biaser biasing the piston unit toward the oil pressure chamber,
between the cylinder part and the piston unit a liquid tight condition being kept at any place between a position where the piston unit has moved closest to the oil pressure chamber and a position where the piston unit has moved closest to the adjustment space,
wherein the pressure adjusting mechanism includes an inner sleeve set inside the plunger accommodating hole, a piston spring as the piston biaser is set in the inner sleeve, and the inner sleeve is fitted with the piston unit, and
wherein the inner sleeve includes a sleeve through hole that extends from an inner circumferential surface to an outer circumferential surface thereof.

### Claim 2 (depends on 1)

The tensioner according to claim 1, wherein a portion in a front to back direction of an inner circumferential surface of the plunger accommodating hole serves as a cylinder inner circumferential surface opposite the piston unit.

### Claim 3 (depends on 1)

The tensioner according to claim 1, wherein the pressure adjusting mechanism includes a first restricting part that restricts movement of the piston unit toward the adjustment space.

### Claim 4 (depends on 1)

The tensioner according to claim 1, wherein the pressure adjusting mechanism includes a second restricting part that restricts movement of the piston unit toward the oil pressure chamber.

### Claim 5 (depends on 4)

The tensioner according to claim 4, wherein the piston spring as the piston biaser has a larger spring force than that of a main spring as the main biaser.

### Claim 6 (depends on 1)

The tensioner according to claim 1, further comprising an oil supply passage that connects outside of the housing with the adjustment space, wherein
the piston unit is configured as a check valve that allows oil to flow from the adjustment space to the oil pressure chamber and prevents oil from flowing from the oil pressure chamber to the adjustment space.

### Claim 7 (depends on 6)

The tensioner according to claim 6, wherein
the piston unit includes a check valve unit and an outer tube member disposed around an outer circumferential surface of the check valve unit, and
the outer tube member includes a piston outer circumferential surface opposite the cylinder part.