Abstract: A projection (21b4) provided at a tip portion of an inner lip portion (21b) of a first cup seal (21) comes in contact with a second side wall (20c) of a recessed portion (20) and a large axial force is exerted in the axial direction on a first tapered inner peripheral surface (21b1) of the first cup seal (21) from a rear side tapered surface (4b2) of a primary piston (4). This makes it possible to reliably hold the first cup seal (21) in the axial direction by utilizing the axial force. Therefore, the first cup seal (21) can be suppressed from moving in the axial direction. In particular, the projection (21b4) of the first cup seal (21) comes in contact with a tapered surface (20c?) of the second side wall (20c) to obtain a further increased axial force, and the first cup seal (21) can be held more reliably.

Abstract: A projection (21b4) provided at a tip portion of an inner lip portion (21b) of a first cup seal (21) comes in contact with a second side wall (20c) of a recessed portion (20) and a large axial force is exerted in the axial direction on a first tapered inner peripheral surface (21b1) of the first cup seal (21) from a rear side tapered surface (4b2) of a primary piston (4). This makes it possible to reliably hold the first cup seal (21) in the axial direction by utilizing the axial force. Therefore, the first cup seal (21) can be suppressed from moving in the axial direction. In particular, the projection (21b4) of the first cup seal (21) comes in contact with a tapered surface (20c?) of the second side wall (20c) to obtain a further increased axial force, and the first cup seal (21) can be held more reliably.

Abstract: A master cylinder of the present invention is disposed with valve bodies (26a) and (28a). Support portions (26b) and (28b) on one end side of these valve bodies (26a) and (28a) are respectively supported in connecting opening portions (22) and (23) of a reservoir (21) so as to be rotatable using these support portions (26b) and (28b) as fulcrums. During the start of operation, when brake fluid flows out from hydraulic chambers (10) and (11) to the reservoir (21), the valve bodies (26a) and (28a) rotate and close such that the flow of the brake fluid is restricted by notches (22a) and (23a), and the dead strokes of pistons (5) and (6) become small. During intake of the brake fluid by pumps; when the brake fluid flows from the reservoir (21) to the hydraulic chambers (10) and (11), the valve bodies (26a) and (28a) rotate and open such that the brake fluid flows to the hydraulic chambers (10) and (11) without its flow being restricted, and fluid self-support performance is ensured.

Abstract: A master cylinder according to the invention has a predetermined number of second axial grooves formed on an outer peripheral surface of a tip portion of a secondary piston at predetermined intervals apart in a circumferential direction. Second radial holes are formed at the rear ends of some of the second axial grooves penetrate between the inner and outer peripheral surfaces of the piston. In an inoperative state, the rear ends of the second axial grooves and the second radial holes are all located to the rear of a seal point of a second cup seal, and a second fluid supply chamber is connected to a second hydraulic pressure chamber via the second axial grooves and the second radial holes. When the rear ends of the second axial grooves and the second radial holes are all moved in front of the seal point, the second fluid supply chamber is disconnected from the second hydraulic pressure chamber.

Abstract: To provide a plunger type master cylinder capable of reducing invalid stroke and preventing residual pressure without impairing durability of a seal ling (70). A piston (91) of the master cylinder has a recess (93) at its outer peripheral surface and a relief port (900) in its recess (93). The seal ring (70) has a seal coupling part (70s) on the inner periphery of the distal end part of an inner peripheral lip (701). The seal coupling part (70s) is located at the opening of the relief portion (900) on the piston (91) side when the brake is in a non-operating position. The distance between said seal coupling part (70s) and said relief port (900) is short. The seal ring (70) additionally has first and second projection parts (7006, 7002) on the inner peripheral surface of the inner peripheral lip (701). By this, a flow passage for working fluid can be obtained on the inner periphery side of the inner peripheral lip (701).

Abstract: To provide a plunger type master cylinder capable of reducing invalid stroke and preventing residual pressure without impairing durability of a seal ling (70). A piston (91) of the master cylinder has a recess (93) at its outer peripheral surface and a relief port (900) in its recess (93). The seal ring (70) has a seal coupling part (70s) on the inner periphery of the distal end part of an inner peripheral lip (701). The seal coupling part (70s) is located at the opening of the relief portion (900) on the piston (91) side when the brake is in a non-operating position. The distance between said seal coupling part (70s) and said relief port (900) is short. The seal ring (70) additionally has first and second projection parts (7006, 7002) on the inner peripheral surface of the inner peripheral lip (701). By this, a flow passage for working fluid can be obtained on the inner periphery side of the inner peripheral lip (701).

Abstract: A master cylinder including a cylinder body having a cylindrical bore and an opening in the circumferential wall for a relief port communicating with the interior of hydraulic reservoir. A piston is slidably inserted into the cylindrical bore to form a hydraulic pressure generating chamber in the cylindrical bore. A cup seal is provided with an inner circumferential lip portion contacting with the piston, an outer circumferential lip portion slidably contacting with the inner circumferential wall of the cylindrical bore, and a base portion connecting the lip portions, which are so arranged as to face to the hydraulic pressure generating chamber. The cup seal cuts the communication between the hydraulic pressure generating chamber and the hydraulic reservoir through the relief port when the top end of the outer circumferential lip portion passes by the relief port.

Abstract: A disc driving device of the type in which two different head units are moved by a linear motor along the radial direction of two discs having different recording densities. If a floppy disc with the standard recording density (lower order mode) is loaded on a disc table and a shock sensor detects the shock, a controller discontinues the recording and/or reproducing processing by a FDD (Floppy Disk Drive).

Abstract: In a master cylinder including: a cylinder body having a cylindrical bore and an opening made in the circumferential wall, for a relief port communicating with the interior of hydraulic reservoir, a piston inserted slidably into said cylindrical bore to form a hydraulic pressure generating chamber in said cylindrical bore; and a cup seal having an inner circumferential lip portion contacting with said piston, an outer circumferential lip portion slidably contacting with the inner circumferential wall of said cylindrical bore, and a base portion connecting said lip portions which are so arranged as to face to said hydraulic pressure generating chamber, whereby said cup seal cuts the communication between said hydraulic pressure generating chamber and said hydraulic reservoir through said relief port when the top end of said outer circumferential lip portions passes by said relief port, the improvement in which means for rotating said cup seal relative to said cylindrical bore with the movement of said piston i

Abstract: File name conversion method, and apparatus, for converting a first file name that can be distinguished by a given operating system into a second file name that can be distinguished both by the given operating system and other operating systems. The method and apparatus insure that the first and second file names do not already exist on an associated recording medium prior to recording the first file name on the recording medium and prior to converting the first file name to the second file name. Also provided is a recording medium on which is recorded a file conversion program for converting the first file name to the second file name and for searching whether or not the file names exist on the recording medium.