Abstract: An accumulator has a pressure vessel, a partition portion comparting an internal space of the pressure vessel into a gas chamber having sealed gaseous matter and a liquid chamber having introduced liquid, and a bellows connected to the partition portion. The partition portion is provided with a bellows connection portion connected to the bellows, a seal arranged in a liquid chamber side of the bellows connection portion, and a seal retention portion fixed to the bellows connection portion and retains the seal. The seal retention portion is constructed by a leaf spring which is elastically deformable in a part thereof, and is structured by integrally forming a fixed portion fixed to the bellows connection portion, and a retention portion retaining the seal. Accordingly, the accumulator can reduce the number of parts of a pressure fluctuation absorbing mechanism, can be easily assembled, and can reduce a parts cost.

Abstract: An impact on the tips of peaks of a metal bellows on contact is reduced, and deformation of the tips of the peaks even on contact is reduced to a minimum. In a free length state of a metal bellows 10 in an early stage of incorporation without extension and contraction, valleys each turn around in a U shape in cross section, peaks each turn around in an arc shape in cross section, the peaks are each provided in a position offset with respect to the center of a pitch between valleys adjacent to the peaks on both sides, and of bellies connected to the peaks on both sides, at least bellies located on the offset side are provided with a constriction protruding inward of the metal bellows.

Abstract: A seal structure is provided which enables a reduction in the number of components and an improvement of the stability in sliding of the seal portion or the backup ring portion. A sealing structure seals two members which move relative to each other, in which a seal portion or a backup ring portion placed between the two members and a bearing portion similarly placed between the two members are formed into an integral structure. The seal portion or the backup ring portion is integrally provided to one end portion in the axial direction or both end portions in the axial direction of the bearing portion having a cylindrical shape. The seal structure is used as a piston seal or a rod seal in hydraulic and pneumatic devices in which a piston is inserted into a shell or a cylinder tube.

Abstract: An accumulator is provided, which is aimed at stabilization in mounting state of a damping member while diminishing the impact on a metal bellows. In an accumulator (100), a damping member (190) formed slidably at the inner circumferential surface of a pressure vessel (110) and suppressing the oscillation of a metal bellows (130) while keeping a gap between the metal bellows (130) and the inner circumferential surface of the pressure vessel (110) is mounted at at least one site of a plurality of annular valley parts of the metal bellows(130) including a plurality of annular crest parts and the plurality of annular valley parts alternately formed therein. In the damping member (190), a radially inward tip is fitted with the valley part, and a radially outward tip is longer than the crest part of the metal bellows radially and outwardly.

Abstract: An accumulator includes a pressure container, a tubular bellows, a bellows cap divisionally defining a liquid chamber and a gas chamber in cooperation with the bellows. A stay provided with a through hole partitions the liquid chamber into a closed liquid chamber on a side of the bellows and an open liquid chamber on a side of the liquid pressure port. The bellows cap includes an elastic abutment part provided with an annular sealing part positioned around the through hole to face the through hole, a buffering part is positioned on a radially inner side of the sealing part, and communication passages always communicating with the through hole are formed in the buffering part of the elastic abutment part.

Abstract: An accumulator capable of suppressing collision of a metal bellows with a pressure vessel. A partition unit 300 includes: a tubular metal bellows 310, one end of which is side fixed to a pressure vessel 200 and which expands and contracts according to pressure in a fluid chamber and pressure in a gas chamber; and a bellows cap 320 which is fixed to another end side of the metal bellows 310, the partition unit 300 further including: a seal member 330 which is provided between the bellows cap 320 and a port 221 and seals a working fluid on the side of the fluid chamber via the metal bellows 310 when the metal bellows 310 contracts; and a sliding unit 350 which is fixed to the bellows cap 320 and slides in an expansion/contraction direction of the metal bellows 310 relative to a stay 400.

Abstract: The invention provides an accumulator which can reduce the number of the parts of the pressure fluctuation absorption mechanism at the liquid expanding time, can simplify assembling and can reduce a cost of the parts. The accumulator has a seal holder which is provided in a bellows cap, and a plate-like seal which is retained by the seal holder. The seal holder is provided with an inward flange-like outer peripheral side engagement portion, and the seal is provided with an outward projection-like inner peripheral side engagement portion which is arranged in an outer peripheral surface of a seal main body and is made of a rubber-like elastic body engaging with the outer peripheral side engagement portion. The bellows cap moves to a position where liquid pressure and gas pressure are balanced with the seal seating on a seat surface due to difference in pressure receiving area.

Abstract: A metal bellows of great durability capable of preventing breakage at both end portions of the metal bellows is provided. The metal bellows is annular-shaped and has, axially repeatedly, a structure in which, from an axial end portion 10c, a belly, a valley, a belly, a peak, and a belly are integrally formed in series sequentially in this order. The end portion 10c has a first connection belly 10d connected to a fitting member 15, and a connection valley 10e and a second connection belly 10f extending sequentially from the first connection belly 10d axially inward. The axial width b1 of the connection valley 10e in a free state is set larger than the axial width of valleys 10i, 10m, . . . or peaks 10g, 10k, . . . in a portion other than the end portion 10c.

Abstract: An accumulator has a pressure vessel, a partition portion comparting an internal space of the pressure vessel into a gas chamber having sealed gaseous matter and a liquid chamber having introduced liquid, and a bellows connected to the partition portion. The partition portion is provided with a bellows connection portion connected to the bellows, a seal arranged in a liquid chamber side of the bellows connection portion, and a seal retention portion fixed to the bellows connection portion and retains the seal. The seal retention portion is constructed by a leaf spring which is elastically deformable in a part thereof, and is structured by integrally forming a fixed portion fixed to the bellows connection portion, and a retention portion retaining the seal. Accordingly, the accumulator can reduce the number of parts of a pressure fluctuation absorbing mechanism, can be easily assembled, and can reduce a parts cost.

Abstract: An accumulator is provided, which is aimed at stabilization in mounting state of a damping member while diminishing the impact on a metal bellows. In an accumulator (100), a damping member (190) formed slidably at the inner circumferential surface of a pressure vessel (110) and suppressing the oscillation of a metal bellows (130) while keeping a gap between the metal bellows (130) and the inner circumferential surface of the pressure vessel (110) is mounted at at least one site of a plurality of annular valley parts of the metal bellows(130) including a plurality of annular crest parts and the plurality of annular valley parts alternately formed therein. In the damping member (190), a radially inward tip is fitted with the valley part, and a radially outward tip is longer than the crest part of the metal bellows radially and outwardly.

Abstract: An impact on the tips of peaks of a metal bellows on contact is reduced, and deformation of the tips of the peaks even on contact is reduced to a minimum. In a free length state of a metal bellows 10 in an early stage of incorporation without extension and contraction, valleys each turn around in a U shape in cross section, peaks each turn around in an arc shape in cross section, the peaks are each provided in a position offset with respect to the center of a pitch between valleys adjacent to the peaks on both sides, and of bellies connected to the peaks on both sides, at least bellies located on the offset side are provided with a constriction protruding inward of the metal bellows.

Abstract: A metal bellows (110) for an accumulator (100) into which a hydraulic fluid is drawn in, has a bellows-shape in which ridge fold portions (110a) and valley fold portions (110b) are formed repeatedly with slope portions (110c) in between, wherein two of the slope portions (110c) that are adjacent to each other via a common ridge fold portion (110a) have: first slope portions (110c1) which extend from the common ridge fold portion (110a) and second slope portions (110c2) each of which extends from each of the first slope portions (110c1) such that a distance therebetween becomes much greater than the first slope portions (110c1) as the second slope portions (110c2) extend toward the adjacent valley fold portions (110b), wherein the first slope portion (110c1) and the second slope portion (110c2) are connected at an inflection point (P).

Abstract: The invention provides an accumulator which can reduce the number of the parts of the pressure fluctuation absorption mechanism at the liquid expanding time, can simplify assembling and can reduce a cost of the parts. The accumulator has a seal holder which is provided in a bellows cap, and a plate-like seal which is retained by the seal holder. The seal holder is provided with an inward flange-like outer peripheral side engagement portion, and the seal is provided with an outward projection-like inner peripheral side engagement portion which is arranged in an outer peripheral surface of a seal main body and is made of a rubber-like elastic body engaging with the outer peripheral side engagement portion. The bellows cap moves to a position where liquid pressure and gas pressure are balanced with the seal seating on a seat surface due to difference in pressure receiving area.

Abstract: An accumulator (100) includes: a housing (110) having an injection opening (112b) into which pressure gas is injected. A gas plug (150) seals the pressure gas in the housing (110). The housing (110) includes: a concave portion to which the gas plug (150) is fitted, and to which the gas plug (150) is welded with the welding portion (151) being melted on its bottom surface (110a). An inclined surface (110c) that extends from an edge portion of the concave portion toward an outside of the housing (110) such that a distance from a center of the injection opening (112b) increases, and the gas plug (150) includes a flange (152) which makes contact with the inclined surface (110c).

Abstract: A metal bellows (110) for an accumulator (100) into which a hydraulic fluid is drawn in, has a bellows-shape in which ridge fold portions (110a) and valley fold portions (110b) are formed repeatedly with slope portions (110c) in between, wherein two of the slope portions (110c) that are adjacent to each other via a common ridge fold portion (110a) have: first slope portions (110c1) which extend from the common ridge fold portion (110a) and second slope portions (110c2) each of which extends from each of the first slope portions (110c1) such that a distance therebetween becomes much greater than the first slope portions (110c1) as the second slope portions (110c2) extend toward the adjacent valley fold portions (110b), wherein the first slope portion (110c1) and the second slope portion (110c2) are connected at an inflection point (P).

Abstract: An accumulator (100) includes: a housing (110) having an injection opening (112b) into which pressure gas is injected. A gas plug (150) seals the pressure gas in the housing (110). The housing (110) includes: a concave portion to which the gas plug (150) is fitted, and to which the gas plug (150) is welded with the welding portion (151) being melted on its bottom surface (110a). An inclined surface (110c) that extends from an edge portion of the concave portion toward an outside of the housing (110) such that a distance from a center of the injection opening (112b) increases, and the gas plug (150) includes a flange (152) which makes contact with the inclined surface (110c).

Abstract: To cause a safety mechanism for an emergency to be activated at lower pressure in comparison with a rupture plate, an accumulator comprises an accumulator housing, a stay having a liquid passage provided in the end surface portion on an end of a stepped tubular portion of the stay, a bellows with a bellows cap, a safety mechanism for pressure drop, and a safety mechanism for an emergency which is structured such that, in an emergency such as a fire, the bellows cap or a member held by the bellows cap presses the stay by high pressure due to the fire in the housing, to buckle the stay at a step of the stepped tubular portion, and open a liquid chamber, wherein a thin portion is provided circumferentially partially at the step of the stay to readily incline the end surface portion of the stay when the stay is buckled.

Abstract: To cause a safety mechanism for an emergency to be activated at lower pressure in comparison with a rupture plate, an accumulator comprises an accumulator housing, a stay having a liquid passage provided in the end surface portion on an end of a stepped tubular portion of the stay, a bellows with a bellows cap, a safety mechanism for pressure drop, and a safety mechanism for an emergency which is structured such that, in an emergency such as a fire, the bellows cap or a member held by the bellows cap presses the stay by high pressure due to the fire in the housing, to buckle the stay at a step of the stepped tubular portion, and open a liquid chamber, wherein a thin portion is provided circumferentially partially at the step of the stay to readily incline the end surface portion of the stay when the stay is buckled.

Abstract: To prevent plastic deformation of a bellows due to a pressure difference between inner and outer sides of the bellows in an outside gas type or inside gas type accumulator, a disc-like gasket is held in a floatable state to a surface close to a stay in a bellows cap by a gasket holder, so that, the disc-like gasket moves together with the bellows cap at a steady operation time, the disc-like gasket moves together with the bellows cap to contact with an end surface portion of the stay, thereby closing the liquid chamber at a zero-down time, and the bellow cap moves toward a position where liquid pressure and gas pressure balance while the disc-like gasket keeps contacting with the stay due to a difference of pressure receiving areas in both the surfaces when the liquid in the liquid chamber is thermally expanded at a zero-down time.

Abstract: To prevent plastic deformation of a bellows due to a pressure difference between inner and outer sides of the bellows in an outside gas type or inside gas type accumulator, a disc-like gasket is held in a float able state to a surface close to a stay in a bellows cap by a gasket holder, so that, the disc-like gasket moves together with the bellows cap at a steady operation time, the disc-like gasket moves together with the bellows cap to contact with an end surface portion of the stay, thereby closing the liquid chamber at a zero-down time, and the bellow cap moves toward a position where liquid pressure and gas pressure balance while the disc-like gasket keeps contacting with the stay due to a difference of pressure receiving areas in both the surfaces when the liquid in the liquid chamber is thermally expanded at a zero-down time.