Abstract: A diaphragm device comprising: a supporting member; a flexible membrane that is supported by the supporting member; and a housing that accommodates the flexible membrane and the supporting member, and wherein the flexible membrane air-tightly separates a first chamber and a second chamber connected to the outside through a through-hole formed in a membrane supporting portion of the supporting member, inside the housing, wherein an avoidance recessed portion to avoid interference with an opening edge of the through-hole is formed at a position corresponding to the through-hole in the flexible membrane, wherein the avoidance recessed portion is provided at a thick portion thicker than the other portion of the flexible membrane, and the thick portion protrudes toward the first chamber.

Abstract: A diaphragm device comprising: a supporting member; a flexible membrane that is supported by the supporting member; and a housing that accommodates the flexible membrane and the supporting member, and wherein the flexible membrane air-tightly separates a first chamber and a second chamber connected to the outside through a through-hole formed in a membrane supporting portion of the supporting member, inside the housing, wherein an avoidance recessed portion to avoid interference with an opening edge of the through-hole is formed at a position corresponding to the through-hole in the flexible membrane, wherein the avoidance recessed portion is provided at a thick portion thicker than the other portion of the flexible membrane, and the thick portion protrudes toward the first chamber.

Abstract: A pressure control reservoir includes a valve ball and a shaft which is movable to move the valve ball to open or close a fluid path leading to a fluid reservoir chamber. The shaft has a tip with a slant surface which has a peripheral edge of a polygonal shape with even numbers of vertices and is inclined to the longitudinal center line of the shaft. Such a polygonal geometry increases an entire or inclined length of the slant surface, which results in an increased range where an angle which the slant surface makes with a plane extending perpendicular to an axial direction of the tip is permitted to be increased without causing the point of contact between the valve ball and the slant surface to be shifted close to the tip of the slant surface when the tip of the shaft moves the valve ball.

Abstract: A pressure control reservoir includes a valve ball and a shaft which is movable to move the valve ball to open or close a fluid path leading to a fluid reservoir chamber. The shaft has a tip with a slant surface which has a peripheral edge of a polygonal shape with even numbers of vertices and is inclined to the longitudinal center line of the shaft. Such a polygonal geometry increases an entire or inclined length of the slant surface, which results in an increased range where an angle which the slant surface makes with a plane extending perpendicular to an axial direction of the tip is permitted to be increased without causing the point of contact between the valve ball and the slant surface to be shifted close to the tip of the slant surface when the tip of the shaft moves the valve ball.

Abstract: A diaphragm device that supports a diaphragm with sandwiching an annular attaching portion, in an axis direction, provided at outer circumference of a flexible film by the support member having a diaphragm mounting portion, wherein at least three protrusions are provided at an outer circumference of the annular attaching portion, and each of the at least three protrusions equally protrudes in a radial direction, and wherein when the annular attaching portion is compressed in the axis direction, each of the at least three protrusions contacts with an inner circumference of the diaphragm mounting portion which faces an outer circumference of the annular attaching portion.

Abstract: A drain port conduit of an ABS actuator, which extends in a housing straight and perpendicularly to ground for making a backpressure chamber communicate with an outside of the housing, is provided on a side of the backpressure chamber with a small diameter portion and on a side of the ground with a large diameter portion. A ring plate is press fitted to the large diameter portion at an axial end thereof on a side of the ground. A diameter of a hole of the ring plate is smaller than an inner diameter of the small diameter portion so that water is restrained from entering into the drain port conduit and, even if entered, from reaching the backpressure chamber.