Rotary damper

Patent metadata

Field	Value
Publication number	US-9605725-B2
Application number	US-201314382672-A
Country	US
Kind code	B2
Filing date	Feb 28, 2013
Priority date	Mar 8, 2012
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A rotary damper includes a housing having an outer cylinder, an inner cylinder coaxially disposed inside the outer cylinder, and a bottom plate closing one end side of the outer cylinder and the inner cylinder, to form an annular liquid chamber with a viscous fluid therein, and a rotor including a cylindrical blade portion rotatably received in the liquid chamber. An annular locking groove extends circumferentially in a first portion at an outer peripheral surface of the inner cylinder, or a second portion facing the first portion on an inner peripheral surface of the blade portion. A locking convex portion projects from the other of the first portion or the second portion, and locked in the locking groove. An annular inside seal member is interposed between the inner cylinder and the blade portion, and an annular outside seal member is interposed between the outer cylinder and the blade portion.

First claim

What is claimed is:

1. A rotary damper, comprising:
a housing including an outer cylinder having a predetermined axis line, an inner cylinder coaxially disposed inside the outer cylinder, and a bottom plate closing one end of the housing in an axis line direction between the outer cylinder and the inner cylinder, wherein an annular liquid chamber is defined by the outer cylinder, the inner cylinder, and the bottom plate, and a viscous fluid is filled in the liquid chamber;
a rotor including a cylindrical blade portion rotatably received in the liquid chamber coaxially with the outer cylinder, and a flange extending radially outwardly from an upper end of the blade portion, and arranged outside of the housing and above an upper surface of the outer cylinder;
an annular locking groove extending in a circumferential direction in one of either a first portion which is an outer peripheral surface of the inner cylinder and is located at an end edge portion on a side opposite to a bottom plate side, or a second portion facing the first portion on an inner peripheral surface of the blade portion;
a locking convex portion projecting from the other of either the first portion or the second portion, and locked in the locking groove so as to control a relative movement in the axis line direction between the housing and the rotor;
an annular inside seal member interposed between a portion on the outer peripheral surface of the inner cylinder and on the bottom plate side more than the first portion, and the inner peripheral surface of the blade portion; and
an annular outside seal member interposed between a vicinity of the other end of the housing in the axis line direction on an inner peripheral surface of the outer cylinder, and an outer peripheral surface of the blade portion,
wherein the inner cylinder includes a slit extending between the end edge portion and a portion above the inside seal member through the annular locking groove or the convex portion so that a part of the inner cylinder elastically deforms radially inwardly to receive and hold the rotor, and
the end edge portion of the inner cylinder is positioned inward of an upper surface of the flange so that the slit of the inner cylinder is positioned inward of the flange.

2. A rotary damper according to claim 1 , wherein an annular outside-seal-member receiving groove extending in the circumferential direction to receive the outside seal member is formed at an end portion in the axis line direction on the outer peripheral surface of the blade portion.

3. A rotary damper according to claim 1 , wherein the inner cylinder further comprises another slit extending between the end edge portion and the portion above the inside seal member through the annular locking groove or the convex portion, and
the slit and said another slit are disposed at a symmetrical position with respect to the axis line to form the end edge portion of the inner cylinder with two arc-shaped halves.

4. A rotary damper according to claim 3 , wherein the annular inside seal member is arranged toward the bottom plate relative to the annular outside seal member in the axis line direction and toward the inner cylinder relative to the annular outside seal member in a radial direction of the housing.

5. A rotary damper according to claim 4 , wherein the flange of the rotor has an outer peripheral surface aligned to that of the outer cylinder immediately above the upper surface of the outer cylinder.

6. A rotary damper, comprising:
a housing including an outer cylinder having a predetermined axis line, an inner cylinder coaxially disposed inside the outer cylinder, and a bottom plate closing one end of the housing in an axis line direction between the outer cylinder and the inner cylinder, wherein an annular liquid chamber is defined by the outer cylinder, the inner cylinder, and the bottom plate, and a viscous fluid is filled in the liquid chamber;
a rotor including a cylindrical blade portion rotatably received in the liquid chamber coaxially with the outer cylinder;
an annular locking groove extending in a circumferential direction in one of either a first portion which is an outer peripheral surface of the inner cylinder and is located at an end edge portion on a side opposite to a bottom plate side, or a second portion facing the first portion on an inner peripheral surface of the blade portion;
a locking convex portion projecting from the other of either the first portion or the second portion, and locked in the locking groove so as to control a relative movement in the axis line direction between the housing and the rotor;
an annular inside seal member interposed between a portion on the outer peripheral surface of the inner cylinder and on the bottom plate side more than the first portion, and the inner peripheral surface of the blade portion;
an annular outside seal member interposed between a vicinity of the other end of the housing in the axis line direction on an inner peripheral surface of the outer cylinder, and an outer peripheral surface of the blade portion;
a seal member housing portion receiving the annular inside seal member; and
an annular seal member groove receiving the annular outside seal member,
wherein the annular outside seal member is disposed at a position adjacent to the edge portion of the outer cylinder, and the annular inside seal member is arranged at a position deviating from the annular outside seal member to the bottom plate in the axis line direction,
the blade portion of the rotor includes
a main body portion for generating a braking torque relative to a rotation of the rotor, and
a thick portion extending upwardly from an upper end of the main body portion and having an outer diameter equal to that of the main body portion and an inner diameter less than that of the main body portion so that a thickness of the thick portion is greater than that of the main body portion in a radial direction of the housing,

the seal member housing portion is formed between an inner peripheral surface of the thick portion and the inner cylinder in the radial direction, and
the annular seal member groove is formed above the seal member housing portion in the axial line direction and between the inner peripheral surface of the outer cylinder and an outer peripheral surface of the thick portion adjacent to the second portion in the radial direction.

7. A rotary damper according to claim 6 , wherein the first and second portions are arranged at a side away from the bottom plate relative to the annular outside seal member.

8. A rotary damper according to claim 7 , wherein a length of the outer peripheral surface of the blade portion between one end of the blade portion and the seal member groove is greater than a length of the inner peripheral surface of the blade portion between the one end of the blade portion and the seal member housing portion.

9. A rotary damper according to claim 8 , wherein the inner cylinder includes
a large diameter portion extending from the bottom plate in the axis line direction,
a small diameter portion disposed above the large diameter portion coaxially therewith and having a diameter smaller than that of the large diameter portion, and
a step portion having an annular flat plate shape extending radially to connect the large diameter portion and the small diameter portion, and
the annular inside seal member contacts the inner peripheral surface of the thick portion and an outer peripheral surface of the small diameter portion to seal the viscous fluid.

Assignees

• Nifco Inc
• Nifco Korea Inc

Inventors

• Seto Masatora
• Lee Young Kook

Classifications

• F16F9/369

  Sealings for elements other than pistons or piston rods, e.g. valves · CPC title

• F16F9/12 Primary

  Devices with one or more rotary vanes turning in the fluid any throttling effect being immaterial, {i.e. damping by viscous shear effect only (F16F9/53 takes precedence; pivoting supports for apparatus or articles placed on stands or trestles F16M11/06)} · CPC title