Abstract: A seal structure is provided to block a clearance between a rotational casing and a fixed housing for driving a crawler of a crawler vehicle. A seal ring is held in a first annular holding groove provided in the fixed housing together with a first O-ring that biases the seal ring toward the outside of the first holding groove. A second holding groove having an opening facing the first holding groove is provided in the rotational casing to hold a slide ring having a higher rigidity than that of the seal ring together with a second O-ring that biases the slide ring toward the seal ring. A foreign object such as mud is thereby prevented from invading a gear chamber without increasing a frictional loss.

Abstract: A seal structure is provided to block a clearance between a rotational casing and a fixed housing for driving a crawler of a crawler vehicle. A seal ring is held in a first annular holding groove provided in the fixed housing together with a first O-ring that biases the seal ring toward the outside of the first holding groove. A second holding groove having an opening facing the first holding groove is provided in the rotational casing to hold a slide ring having a higher rigidity than that of the seal ring together with a second O-ring that biases the slide ring toward the seal ring. A foreign object such as mud is thereby prevented from invading a gear chamber without increasing a frictional loss.

Abstract: A seal structure is provided to block a clearance between a rotational casing and a fixed housing for driving a crawler of a crawler vehicle. A seal ring is held in a first annular holding groove provided in the fixed housing together with a first O-ring that biases the seal ring toward the outside of the first holding groove. A second holding groove having an opening facing the first holding groove is provided in the rotational casing to hold a slide ring having a higher rigidity than that of the seal ring together with a second O-ring that biases the slide ring toward the seal ring. A foreign object such as mud is thereby prevented from invading a gear chamber without increasing a frictional loss.

Abstract: A seal member includes an annular fitting part and an annular dust lip. The fitting part fits on an inner circumference of a tubular member. The dust lip extends from the fitting part toward a side opposite from the tubular member such that a diameter of an inner circumference of the dust lip gradually decreases, and a distal end portion of the dust lip slides on an outer circumferential surface of a shaft member. A metal insert includes a reinforcing ring and a reinforcing extension piece. The reinforcing ring stands along the inner circumference of the tubular member. The reinforcing extension piece extends from the reinforcing ring toward a side opposite from the tubular member, and inclines such that a distal end of the reinforcing extension piece approaches the shaft member. The reinforcing ring is arranged in the fitting part, whereas the reinforcing extension piece is arranged in the dust lip.

Abstract: A seal member includes an annular fitting part and an annular dust lip. The fitting part fits on an inner circumference of a tubular member. The dust lip extends from the fitting part toward a side opposite from the tubular member such that a diameter of an inner circumference of the dust lip gradually decreases, and a distal end portion of the dust lip slides on an outer circumferential surface of a shaft member. A metal insert includes a reinforcing ring and a reinforcing extension piece. The reinforcing ring stands along the inner circumference of the tubular member. The reinforcing extension piece extends from the reinforcing ring toward a side opposite from the tubular member, and inclines such that a distal end of the reinforcing extension piece approaches the shaft member. The reinforcing ring is arranged in the fitting part, whereas the reinforcing extension piece is arranged in the dust lip.

Abstract: A seal structure is provided to block a clearance between a rotational casing and a fixed housing for driving a crawler of a crawler vehicle. A seal ring is held in a first annular holding groove provided in the fixed housing together with a first O-ring that biases the seal ring toward the outside of the first holding groove. A second holding groove having an opening facing the first holding groove is provided in the rotational casing to hold a slide ring having a higher rigidity than that of the seal ring together with a second O-ring that biases the slide ring toward the seal ring. A foreign object such as mud is thereby prevented from invading a gear chamber without increasing a frictional loss.

Abstract: A sealing device adapted to seal an outer periphery of a shaft member inserted into a tubular member includes a dust seal lip arranged on an outer side of the tubular member and an oil seal lip arranged on an inner side of the tubular member to form a space for accumulating working fluid between the oil seal lip and the dust seal lip. The dust seal lip includes a main lip portion and an auxiliary lip portion formed to be closer to the oil seal lip than the main lip portion. A maximum value of a surface pressure gradient absolute value of the inner side in the auxiliary lip portion is set to be larger than that of a surface pressure gradient absolute value of the outer side in the auxiliary lip portion.

Abstract: A high-friction fluid seal used for high-friction sealing, comprising a fluid seal lip provided on the working fluid filling side to intercept a working fluid; and a dust lip provided on the working fluid non-filling side (the outer side) of the fluid seal lip to intercept dust coming from the outside, wherein the thickness of a working fluid film formed on the extension stroke by the dust lip is smaller than the thickness of a working fluid film formed on the extension stroke by the fluid seal lip.

Abstract: There is provided a hydraulic damper including a receiving space formed between a rod guide of a cylinder and an insert metal, for temporarily retaining a working fluid leaked out from an oil chamber through a sliding gap of a rod. The hydraulic damper further includes a communicating path for communicating between a reservoir and the receiving space, and a check valve for allowing a flow of the working fluid only from the receiving space to the reservoir. Either one of a lip part of the check valve or a seat surface provided on the rod guide is formed with a sealing projected part protruding from a mutual contact surface.

Abstract: A high-friction fluid seal used for high-friction sealing, comprising a fluid seal lip provided on the working fluid filling side to intercept a working fluid; and a dust lip provided on the working fluid non-filling side (the outer side) of the fluid seal lip to intercept dust coming from the outside, wherein the thickness of a working fluid film formed on the extension stroke by the dust lip is smaller than the thickness of a working fluid film formed on the extension stroke by the fluid seal lip.

Abstract: There is provided a hydraulic dumper including an receiving space 15 formed between the rod guide 4 of the cylinder 1 and the insert metal 5 and for temporarily retaining the working fluid leaked out from the oil chamber R1 through the sliding gap of the rod 3, a communicating path 4d for communicating the reservoir R and the receiving space 15, and a check valve 9 for allowing the flow of the working fluid only from the receiving space 15 to the reservoir R, wherein, either one of the lip part 9a of the check valve or the seat surface 4c provided on the rod guide 4 is formed with a sealing projected part 10, 11 protruding from the mutual contact surface.