# US 2014/0190779 A1 · Rotational speed reduction device for truck tailgate

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- Number: US 2014/0190779 A1
- Document ID: US20140190779A1
- Status: Published application
- Kind: A1
- Application number: 14/232,410
- Filed: 2012-07-19
- Published: 2014-07-10
- Earliest claimed: 2011-07-28
- Assignees: Oiles Corporation
- Inventors: Naohiro Horita; Ryohei Kaneko
- Web page: https://patentgrep.com/patent/US20140190779A1

## CPC

- B62D 33/03: by swinging down {(B62D33/0273 takes precedence)}
- B62D 33/027: movable
- E05F 5/022: {specially adapted for vehicles, e.g. for hoods or trunks}
- F16F 9/145: {involving only rotary movement of the effective parts (wing closers or openers with fluid brakes of the rotary type E05F3/14)}
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- E05F: DEVICES FOR MOVING WINGS INTO OPEN OR CLOSED POSITION; CHECKS FOR WINGS; WING FITTINGS NOT OTHERWISE PROVIDED FOR, CONCERNED WITH THE FUNCTIONING OF THE WING
- F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION

## Abstract

A rotational speed reduction device 1 for a truck tailgate includes a housing 5, a rotor 8 disposed inside the housing 5, a viscous fluid 14a accommodated in an inner space 13a, passages 15a and 16a provided in the rotor 8, a one-way valve 19 disposed in the passage 15a, and a one-way valve 20a disposed in the passage 16a.

## Claims

### Claim 1

A rotational speed reduction device for a truck tailgate comprising:
a housing having a cylindrical inner peripheral surface and an inward protrusion formed integrally on the inner peripheral surface in such a manner as to protrude radially inwardly from the inner peripheral surface;
a rotor which has a cylindrical outer peripheral surface opposing the inner peripheral surface of said housing and has an outward protrusion formed integrally on the outer peripheral surface in such a manner as to protrude radially outwardly from the outer peripheral surface, and which is rotatably disposed inside said housing;
a viscous fluid accommodated in an inner space which is defined by the inner peripheral surface of said housing, the outer peripheral surface of said rotor, and side surfaces of the inward protrusion opposing each other in a rotational direction, and which is partitioned into two, a first and a second, chambers, by the outward protrusion of said rotor;
a first and a second passage provided in said rotor so as to allow the two, the first and the second, chambers to communicate with each other;
a first one-way valve disposed in said first passage such that, in the rotation of said rotor with respect to said housing in one direction corresponding to the rotation in an opening direction of a truck tailgate, the flow of said viscous fluid from one of the two chambers to another one thereof through said first passage is allowed by an increase by more than a fixed level of the internal pressure of said viscous fluid in the one of the two chambers owing to the rotation in the one direction, whereas, in the rotation of said rotor with respect to said housing in another direction corresponding to the rotation in a closing direction of the truck tailgate, the flow of said viscous fluid from the other chamber to the one chamber through said first passage is inhibited; and
a second one-way valve disposed in said second passage such that, in the rotation of said rotor with respect to said housing in the one direction, the flow of said viscous fluid from the one chamber to the other chamber through said second passage is inhibited, whereas, in the rotation of said rotor with respect to said housing in the other direction, the flow of said viscous fluid from the other chamber to the one chamber through said second passage is allowed,
wherein said first one-way valve has a valve seat formed in said rotor, a spherical body which is seated on the valve seat and is movably disposed in said rotor, and a resilient member which is, at one end thereof, brought into contact with the spherical body so as to resiliently press the spherical body against the valve seat,
said second passage has at least one notch formed in a protruding end of the outward protrusion, and
said second one-way valve has a valve element provided at the protruding end of the outward protrusion movably in the rotational direction in such a manner as to straddle the protruding end of the outward protrusion,
the valve element including a completely closing piece portion disposed on one surface of the outward protrusion which receives the internal pressure of said viscous fluid in the one chamber, so as to inhibit the flow of said viscous fluid from the one chamber to the other chamber through said second passage by closing the notch in the rotation of said rotor with respect to said housing in the one direction, an incompletely closing piece portion disposed on another surface of the outward protrusion which receives the internal pressure of said viscous fluid in the other chamber, so as to allow the flow of said viscous fluid from the other chamber to the one chamber through said second passage by partially closing the notch in the rotation of said rotor with respect to said housing in the other direction, and a connecting portion which is disposed at the protruding end of the outward protrusion and which is in contact with the inner peripheral surface of said housing and the protruding end of the outward protrusion slidably in the rotational direction, so as to connect together the completely closing piece portion and the incompletely closing piece portion.

### Claim 2 (depends on 1)

The rotational speed reduction device for a truck tailgate according to claim 1, wherein said housing includes a hollow cylindrical body having the cylindrical inner peripheral surface which defines the inner space and has the inward protrusion formed integrally thereon, a cover portion provided integrally on one axial end portion of the hollow cylindrical body, and a cover member which is attached at another axial end portion of the hollow cylindrical body and has a through hole in its center.

### Claim 3 (depends on 1)

The rotational speed reduction device for a truck tailgate according to claim 1, wherein said rotor includes a rotor body which has the outer peripheral surface with the outward protrusion formed integrally thereon and a hollow cylindrical body which is fitted inside the rotor body, said first passage being formed in the rotor body and the hollow cylindrical body, the spherical body being disposed in a hollow portion of the hollow cylindrical portion, and the valve seat being formed in the hollow cylindrical body.

### Claim 4 (depends on 1)

The rotational speed reduction device for a truck tailgate according to claim 1, wherein the inward protrusion has a protrusion body formed integrally on the inner peripheral surface of the housing and a seal member by which a protruding end portion of the protrusion body is covered and which is brought into contact with the outer peripheral surface of said rotor slidably in the rotational direction.

### Claim 5 (depends on 1)

The rotational speed reduction device for a truck tailgate according to claim 1, wherein the spherical body is disposed in said first passage such that, at the time of receiving the internal pressure of said viscous fluid from the other chamber in the rotation of said rotor with respect to said housing in the other direction, the spherical body is seated on the valve seat to close said first passage, whereas, at the time of receiving the internal pressure of said viscous fluid, which has increased by more than a fixed level, from the one chamber due to the rotation of said rotor with respect to said housing in the one direction, the spherical body is moved away from the valve seat to open said first passage.

### Claim 6 (depends on 1)

The rotational speed reduction device for a truck tailgate according to claim 1, wherein, at the time of receiving the internal pressure of said viscous fluid from the one chamber, the completely closing piece portion is adapted to close the notch by coming into contact with the one surface of the outward protrusion, whereas, at the time when the incompletely closing piece portion receives the internal pressure of said viscous fluid from the other chamber, the completely closing piece portion is adapted to move away from the surface of the outward protrusion in consequence of the movement of the connecting portion entailed by the movement of the incompletely closing piece portion toward the other surface of the outward protrusion.

### Claim 7 (depends on 1)

The rotational speed reduction device for a truck tailgate according to claim 1, wherein said housing is adapted to be secured to a vehicle body of the truck, and said rotor is adapted to be coupled to a rotating shaft of the tailgate.