Hydraulic damper

Patent metadata

Field	Value
Publication number	US-9664205-B2
Application number	US-201514719989-A
Country	US
Kind code	B2
Filing date	May 22, 2015
Priority date	May 23, 2014
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A hydraulic damper disposed in a discharge-side passage of a hydraulic pump comprises a bladder made of elastic material and formed into a cylindrical shape, a core, and a plug. The bladder includes a spherical closed end portion at its one end and an open end portion at its the other end. The open end portion includes an annular flange portion extending outwardly in the radial direction. The core includes an inserted portion to be inserted into the bladder and an annular flange portion extending outwardly in the radial direction so as to contact with an end face of the open end portion of the bladder. The inserted portion has a large-diameter portion, a small-diameter portion and a gradually-changing diameter portion formed between the large-diameter portion and the small-diameter portion and forming an air chamber in the bladder together with the small chamber.

First claim

What is claimed is:

1. A hydraulic damper comprising:
a bladder made of elastic material and possessing a cylindrical shape, the bladder possessing one end and an other end, the bladder comprising a spherical closed end portion at the one end and an open end portion at the other end, the open end portion including an annular flange portion extending outwardly in the radial direction, the open end portion comprising an end face;
a core including an inserted portion positioned within the bladder and an annular flange portion extending outwardly in the radial direction and contacting the end face of the open end portion of the bladder;
the inserted portion comprising a large-diameter portion, a small-diameter portion and a gradually-changing diameter portion, the large-diameter portion being fitted in the open end portion of the bladder to seal the open end portion in a liquid-tight manner, the small-diameter portion extending in the bladder from the large-diameter portion toward the spherical closed end portion of the bladder, and the gradually-changing diameter portion being between the large-diameter portion and the small-diameter portion and forming an air chamber in the bladder together with the small-diameter portion, the small-diameter portion of the inserted portion of the core possessing a distal-most end, the distal-most end of the small diameter portion of the inserted portion of the core being spherically shaped; and
a plug accommodating the annual flange portion of the bladder and the annual flange portion of the core and binding the bladder to the core at the annual flange portion of the bladder and the annual flange portion of the core,
wherein the hydraulic damper is disposed in a discharge-side passage of a hydraulic pump.

2. The hydraulic damper according to claim 1 , wherein
the bladder comprises a cylindrical portion which possesses an inner diameter and an outer diameter, and
the inner diameter of a cylindrical portion of the bladder is less than or equal to half of the outer diameter of the cylindrical portion of the bladder.

3. The hydraulic damper according to claim 1 , wherein an outer diameter of the small-diameter portion of the core is set on the basis of a buckling load of a cylindrical portion of the bladder under external pressure and an inner surface of the cylindrical portion of the bladder comes in contact with the small-diameter portion of the core in response to the external pressure so as to restrict buckling deformation of the cylindrical portion of the bladder.

4. The hydraulic damper according to claim 2 , wherein an outer diameter of the small-diameter portion of the core is set on the basis of a buckling load of the cylindrical portion of the bladder under external pressure and an inner surface of the cylindrical portion of the bladder comes in contact with the small-diameter portion of the core in response to the external pressure so as to restrict buckling deformation of the cylindrical portion of the bladder.

5. The hydraulic damper according to claim 1 , further comprising
a housing, the entirety of the outer surface of the closed end of the bladder being exposed within the housing.

6. The hydraulic damper according to claim 5 , wherein
the small-diameter portion extends within the bladder and comprises a proximal-most end connected to the distal end of the gradually-changing diameter portion and a distal-most end extending towards the closed end of the bladder, and
the small-diameter portion possesses an outer diameter, the outer diameter of distal-most end of the small-diameter portion being not greater than the outer diameter of the proximal-most end of the small-diameter portion.

7. A hydraulic damper comprising:
a housing;
a bladder positioned within the housing, the bladder being made of an elastic material, the bladder extending in a longitudinal direction from a closed end to an open end opposite to the closed end of the bladder, the open end including an annular flange portion extending outwardly in a radial direction, the open end comprising an end face and possessing an inner surface, the closed end of the bladder possessing an outer surface;
a core including an inserted portion positioned within the bladder and an annular flange portion extending outwardly in the radial direction and contacting the end face of the open end of the bladder;
the inserted portion comprising a large-diameter portion, a small-diameter portion and a gradually-changing diameter portion between the large-diameter portion and the small-diameter portion, the large-diameter portion possessing an outer surface in contact with the inner surface of the open end of the bladder to seal the open end in a liquid-tight manner, the small-diameter portion extending within the bladder from the large-diameter portion toward the closed end of the bladder, and the gradually-changing diameter portion being between the large-diameter portion and the small-diameter portion, the gradually-changing diameter portion possessing an outer surface and the small-diameter portion possessing an outer surface;
an air chamber within the bladder between the outer surface of the small-diameter portion, the outer surface of the gradually-changing diameter portion and the inner surface of the bladder;
a plug accommodating the annual flange portion of the bladder and the annual flange portion of the core and binding the bladder to the core at the annual flange portion of the bladder and the annual flange portion of the core; and
the entirety of the outer surface of the closed end of the bladder being exposed within the housing.

8. The hydraulic damper according to claim 7 , wherein
the bladder comprises a cylindrical portion which possesses an inner diameter and an outer diameter, and
the inner diameter of a cylindrical portion of the bladder is less than or equal to half of the outer diameter of the cylindrical portion of the bladder.

9. The hydraulic damper according to claim 7 , wherein an outer diameter of the small-diameter portion of the core is set on the basis of a buckling load of a cylindrical portion of the bladder under external pressure and an inner surface of the cylindrical portion of the bladder comes in contact with the small-diameter portion of the core in response to the external pressure so as to restrict buckling deformation of the cylindrical portion of the bladder.

10. A hydraulic damper comprising:
a bladder being made of an elastic material, the bladder extending in a longitudinal direction from a closed end to an open end opposite to the closed end of the bladder, the open end including an annular flange portion extending outwardly in a radial direction, the open end comprising an end face and possessing an inner surface, the closed end of the bladder possessing an outer surface;
a core including an inserted portion positioned within the bladder and an annular flange portion extending outwardly in the radial direction and contacting the end face of the open end of the bladder, the core possessing a distal-most end;
the inserted portion comprising a large-diameter portion, a small-diameter portion and a gradually-changing diameter portion between the large-diameter portion and the small-diameter portion, the large-diameter portion possessing an outer surface in contact with the inner surface of the open end of the bladder to seal the open end in a liquid-tight manner, the gradually-changing diameter portion comprising a proximal end connected to the large-diameter portion and a distal end connected to the small-diameter portion, the gradually-changing diameter portion possessing an outer diameter, the outer diameter of the gradually-changing diameter portion decreasing from the proximal

Assignees

• Advics Co Ltd

Inventors

• Hashida Koichi

Classifications

• F15B1/021 Primary

  used for damping · CPC title

• F04B53/16

  Casings; Cylinders; Cylinder liners or heads; Fluid connections · CPC title

• F04B11/0008

  using accumulators · CPC title

• F16L55/04

  Devices damping pulsations or vibrations in fluids {(F16L55/02 takes precedence)} · CPC title

• F04B11/00 Primary

  Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation · CPC title