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 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: The invention provides a clutch seal which can enhance a durability of a membrane portion which is a constituting part of a seal and is constructed by a rubber-like elastic body, and can inhibit a working fluid from standing in a concave surface of the membrane portion. The clutch seal of the invention is an annular seal interposed between a clutch plate in a dry clutch and a piston pressing the clutch plate, has a middle ring fixed to the piston between an outer ring and an inner ring which are fixed to a clutch housing, and has membrane portions constructed by a rubber-like elastic body respectively between the outer ring and the middle ring and between the inner ring and the middle ring, wherein the middle ring is arranged at an intermediate position of a stroke in an initial shape of the membrane portion.

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: In order to prevent gaps from occurring in corner sections in a section where three surfaces are joined together, comprising the combination of a housing, grommet and cover, or the like, thereby improve sealing, a seal structure, which is provided with a housing in which a notch-shaped grommet-mounting section is disposed, a grommet, a cover and a metal substrate gasket, is provided, wherein the grommet is provided with a seal projection, and the seal projection forms a protruding section due to a portion of the seal projection protruding toward the metal substrate gasket when the seal projection makes intimate contact with the inner surface of the grommet-mounting section. The metal substrate gasket is provided with two seal lines and a groove-shaped recess between the seal lines. When nipped, the protruding section of the seal projection is tightly compressed inside the groove-shaped recess in the metal substrate gasket.

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: In an accumulator having an accumulator housing which is provided with an oil port connected to a pressure piping of equipment, and an inner portion of the accumulator housing being sectioned into a gas chamber filling with gas and a fluid chamber communicating with the oil port by a bellows and a bellows cap, the bellows cap seals the fluid chamber by coming into contact with a seal on the basis of movement in a stroke in the case that a pressure of the pressure piping is decreased, and the seal is retained by a seal retaining portion which is provided in an inner peripheral side of the seal. In the accumulator, a seal diameter of the seal is set to be larger than an effective diameter of the bellows at a position where the seal comes into contact with the bellows cap.

Abstract: An accumulator has a seal member retained to a port hole side of a bellows cap via a seal holder. The seal member comes into contact with a seal portion so as to occlude a liquid chamber in the case that an operation of a device stops and the pressure within a pressure piping is lowered. The seal member moves in a direction that the bellows cap moves away from the seal portion while being in contact with the seal portion when the liquid confined in the liquid chamber thermally expands in a state in which the liquid chamber is occluded. The seal member is obtained by attaching a flexible portion constructed by a rubber-like elastic body to an outer peripheral surface of a rigid plate, and the flexible portion allows relative movement of the bellows cap by shear deformation on the basis of engagement with the seal holder.

Abstract: The invention provides a clutch seal which can enhance a durability of a membrane portion which is a constituting part of a seal and is constructed by a rubber-like elastic body, and can inhibit a working fluid from standing in a concave surface of the membrane portion. The clutch seal of the invention is an annular seal interposed between a clutch plate in a dry clutch and a piston pressing the clutch plate, has a middle ring fixed to the piston between an outer ring and an inner ring which are fixed to a clutch housing, and has membrane portions constructed by a rubber-like elastic body respectively between the outer ring and the middle ring and between the inner ring and the middle ring, wherein the middle ring is arranged at an intermediate position of a stroke in an initial shape of the membrane portion.

Abstract: An accumulator has a seal member retained to a port hole side of a bellows cap via a seal holder. The seal member comes into contact with a seal portion so as to occlude a liquid chamber in the case that an operation of a device stops and the pressure within a pressure piping is lowered. The seal member moves in a direction that the bellows cap moves away from the seal portion while being in contact with the seal portion when the liquid confined in the liquid chamber thermally expands in a state in which the liquid chamber is occluded. The seal member is obtained by attaching a flexible portion constructed by a rubber-like elastic body to an outer peripheral surface of a rigid plate, and the flexible portion allows relative movement of the bellows cap by shear deformation on the basis of engagement with the seal holder.

Abstract: In an accumulator having an accumulator housing which is provided with an oil port connected to a pressure piping of equipment, and an inner portion of the accumulator housing being sectioned into a gas chamber filling with gas and a fluid chamber communicating with the oil port by a bellows and a bellows cap, the bellows cap seals the fluid chamber by coming into contact with a seal on the basis of movement in a stroke in the case that a pressure of the pressure piping is decreased, and the seal is retained by a seal retaining portion which is provided in an inner peripheral side of the seal. In the accumulator, a seal diameter of the seal is set to be larger than an effective diameter of the bellows at a position where the seal comes into contact with the bellows cap.

Abstract: In order to prevent gaps from occurring in corner sections in a section where three surfaces are joined together, comprising the combination of a housing, grommet and cover, or the like, thereby improve sealing, a seal structure, which is provided with a housing in which a notch-shaped grommet-mounting section is disposed, a grommet, a cover and a metal substrate gasket, is provided, wherein the grommet is provided with a seal projection, and the seal projection forms a protruding section due to a portion of the seal projection protruding toward the metal substrate gasket when the seal projection makes intimate contact with the inner surface of the grommet-mounting section. The metal substrate gasket is provided with two seal lines and a groove-shaped recess between the seal lines. When nipped, the protruding section of the seal projection is tightly compressed inside the groove-shaped recess in the metal substrate gasket.

Abstract: A hybrid driving force transmission device is provided with a multiple-plate dry clutch, a piston, a piston arm, a return spring, bellows elastic seal components and an arm fixing plate. The return spring applies biasing force to the piston arm in the release direction of the clutch, during the release period of the multiple-plate dry clutch. The bellows elastic seal member is secured or maintained in a position on the side wall of a clutch drum and seals a through hole and arm distal end from the clutch chamber, and undergoes an elastic deformation following the stroke movement of the arm distal end. The arm fixing plate is integrally provided with the bellows elastic seal member, is fixed to the arm distal end, and when the multiple-plate dry clutch is engaged, is configured to contact the clutch plate for transferring the clutch engagement force.

Abstract: A hybrid driving force transmission device is provided with a multiple-plate dry clutch, a piston, a piston arm, a return spring, bellows elastic seal components and an arm fixing plate. The return spring applies biasing force to the piston arm in the release direction of the clutch, during the release period of the multiple-plate dry clutch. The bellows elastic seal member is secured or maintained in a position on the side wall of a clutch drum and seals a through hole and arm distal end from the clutch chamber, and undergoes an elastic deformation following the stroke movement of the arm distal end. The arm fixing plate is integrally provided with the bellows elastic seal member, is fixed to the arm distal end, and when the multiple-plate dry clutch is engaged, is configured to contact the clutch plate for transferring the clutch engagement force.

Abstract: An outer gas type or inner gas type accumulator has a mechanism for reducing a pressure difference generated when liquid in a liquid chamber and gas expand thermally at a zero-down time, the pressure difference between the inside and outside of a bellows is reduced to suppress abnormal deformation of the bellows, a movable plate supported by a spring is provided at the bellows cap side of an oil port, the movable plate is supported by the spring and away from a seal in normal operation, the movable plate is pushed by the bellows cap and contacts with the seal while elastically deforming the spring, in a zero-down state, and when the liquid and the gas expand thermally in the zero-down state, the bellows cap moves to a position where the liquid pressure and the gas pressure balance, while the movable plate keeps contact with the seal.

Abstract: To restrain abnormal deformation of a bellows due to a pressure difference between the inside and outside thereof, an outside gas type accumulator includes a pressure difference regulation mechanism (21) having a movable plate (22) supported by a coil spring (23) on the oil port (4) side of a bellows cap (8), the plate (22) moves together with the cap (8) in a state of being supported by the spring (23), during normal operation, the plate (22) moves together with the cap (8) to be brought into contact with a seal (13) at zero-down time, and the plate (22) keeps contact with the seal (13) and the cap (8) moves to a position where liquid pressure and gas pressure balances while compressing the spring (23) when the liquid and the charged gas expand thermally.

Abstract: An outer gas type or inner gas type accumulator has a mechanism for reducing a pressure difference generated when liquid in a liquid chamber and gas expand thermally at a zero-down time, the pressure difference between the inside and outside of a bellows is reduced to suppress abnormal deformation of the bellows, a movable plate supported by spring means is provided at the bellows cap side of an oil port, the movable plate is supported by the spring means and away from a seal in normal operation, the movable plate is pushed by the bellows cap and contacts with the seal while elastically deforming the spring means, in a zero-down state, and when the liquid and the gas expand thermally in the zero-down state, the bellows cap moves to a position where the liquid pressure and the gas pressure balance, while the movable plate keeps contact with the seal.

Abstract: To prevent abnormal deformation of a bellows, an accumulator has a regulation mechanism for reducing a pressure difference generated when liquid sealed in a liquid chamber and charged gas are thermally expanded at a zero-down time, a seal plate is arranged in an inner peripheral side of a bellows floating end, an elastically deformable thin plate is bonded to the seal plate, an outer peripheral portion of the thin plate is bonded to the bellows floating end, the seal plate is away from a seal at a time of a steady operation, the seal plate contacts with the seal at a zero-down time, and the thin plate is elastically deformed to make liquid pressure balance with gas pressure while the seal plate being kept in contact with the seal when the liquid and gas are thermally expanded.

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 restrain abnormal deformation of a bellows due to a pressure difference between the inside and outside thereof, an outside gas type accumulator includes a pressure difference regulation mechanism (21) having a movable plate (22) supported by a coil spring (23) on the oil port (4) side of a bellows cap (8), the plate (22) moves together with the cap (8) in a state of being supported by the spring (23), during normal operation, the plate (22) moves together with the cap (8) to be brought into contact with a seal (13) at zero-down time, and the plate (22) keeps contact with the seal (13) and the cap (8) moves to a position where liquid pressure and gas pressure balances while compressing the spring (23) when the liquid and the charged gas expand thermally.