Abstract: A yoke is provided with a notch, notched from two points P1 and P2 on a circumference forming a sleeve-side insertion hole toward the outside of the circumference, the notch having a minimum distance between the points P1 and P2 as a width W and the distance from a straight line linking the points P1 and P2 in a direction orthogonal to the straight line as a length L. The width W of the notch is set on the basis of a target attraction force for attracting a plunger, the attraction force increasing with an increase in the width W, and the length L of the notch is greater than or equal to a prescribed length Ld where the attraction force increasing with an increase in the length L becomes constant at the target attraction force in the set width W irrespective of an increase in the length L.

Abstract: A yoke is provided with a notch, notched from two points P1 and P2 on a circumference forming a sleeve-side insertion hole toward the outside of the circumference, the notch having a minimum distance between the points P1 and P2 as a width W and the distance from a straight line linking the points P1 and P2 in a direction orthogonal to the straight line as a length L. The width W of the notch is set on the basis of a target attraction force for attracting a plunger, the attraction force increasing with an increase in the width W, and the length L of the notch is greater than or equal to a prescribed length Ld where the attraction force increasing with an increase in the length L becomes constant at the target attraction force in the set width W irrespective of an increase in the length L.

Abstract: A brake disc applies braking torque to a vehicle wheel by sliding against friction pads. The brake disc is configured from at least one or more auxiliary discs that slide against the friction pads, main discs in surface contact with the auxiliary discs at surfaces on the sides opposite the surfaces against which the auxiliary discs and friction pads slide, and a hat member that secures the main discs and the auxiliary disc in a state of being capable of slight displacement relative to each other.

Abstract: A hydraulic damper disposed in a discharge-side passage of a hydraulic pump comprises a bladder made of elastic material and formed into a cylindrical shape, a core, and a plug. The bladder includes a spherical closed end portion at its one end and an open end portion at its the other end. The open end portion includes an annular flange portion extending outwardly in the radial direction. The core includes an inserted portion to be inserted into the bladder and an annular flange portion extending outwardly in the radial direction so as to contact with an end face of the open end portion of the bladder. The inserted portion has a large-diameter portion, a small-diameter portion and a gradually-changing diameter portion formed between the large-diameter portion and the small-diameter portion and forming an air chamber in the bladder together with the small chamber.

Abstract: A hydraulic damper disposed in a discharge-side passage of a hydraulic pump comprises a bladder made of elastic material and formed into a cylindrical shape, a core, and a plug. The bladder includes a spherical closed end portion at its one end and an open end portion at its the other end. The open end portion includes an annular flange portion extending outwardly in the radial direction. The core includes an inserted portion to be inserted into the bladder and an annular flange portion extending outwardly in the radial direction so as to contact with an end face of the open end portion of the bladder. The inserted portion has a large-diameter portion, a small-diameter portion and a gradually-changing diameter portion formed between the large-diameter portion and the small-diameter portion and forming an air chamber in the bladder together with the small chamber.

Abstract: A screw pump includes a casing including a main accommodating bore and plural sub accommodating bores, a main rotor adapted to be rotatably accommodated in the main accommodating bore, and plural sub rotors adapted to be respectively rotatably accommodated in the sub accommodating bores. Each sub rotor is adapted to engage the main rotor. A cross sectional shape of a flank surface of the main rotor, which is taken in a direction perpendicular to an axial direction of the main rotor, is formed along an epitrochoid traced by an edge of the sub rotor not to include an undercut shape. Further, a cross sectional shape of a flank surface of each sub rotor, which is taken in a direction perpendicular to an axial direction of the sub rotor, is formed along an epitrochoid traced by an edge of the main rotor not to include an undercut shape.

Abstract: A vehicle brake system, capable of realizing a brake-by-wire construction which can be installed in vehicles in the same manner as conventional brake systems, is provided with a booster device, a master cylinder, wheel brakes, and a hydraulic pressure control device interposed between the master cylinder and the wheel brakes. The system is further provided with a stroke sensor for detecting the moving stroke of a brake pedal, a simulator for applying to the brake pedal a pseudo reaction force corresponding to the moving stroke of the brake pedal, a play or idling component arranged between the booster device and the hydraulic pressure control device for absorbing the moving stroke of the brake pedal by a predetermined amount, and an electronic control device for controlling the hydraulic pressure control device based on an input from the stroke sensor.

Abstract: A screw pump includes a casing including a main accommodating bore and plural sub accommodating bores, a main rotor adapted to be rotatably accommodated in the main accommodating bore, and plural sub rotors adapted to be respectively rotatably accommodated in the sub accommodating bores. Each sub rotor is adapted to engage the main rotor. A cross sectional shape of a flank surface of the main rotor, which is taken in a direction perpendicular to an axial direction of the main rotor, is formed along an epitrochoid traced by an edge of the sub rotor not to include an undercut shape. Further, a cross sectional shape of a flank surface of each sub rotor, which is taken in a direction perpendicular to an axial direction of the sub rotor, is formed along an epitrochoid traced by an edge of the main rotor not to include an undercut shape.

Abstract: To provide a negative pressure type booster device which has a high responsiveness even when a brake pedal is stepped on strongly and which is simplified and compact in construction. To this end, a passage 45 communicating directly with the atmosphere is provided between the internal surface of a sliding cylindrical portion 8b of a valve piston 8 and the external surface of a silencer 27, and the atmospheric air is enabled to be admitted from the passage 45 to a variable pressure chamber 6 directly without passing through the silencer 27 when an input member is advanced beyond a predetermined distance relative to the valve piston.

Abstract: In a vacuum type brake booster, the reaction of output transmitted from an output shaft to a reaction member is transmitted to a valve body, a plunger, and a stepped pin. A valve mechanism, which is assembled to an axial hole of the valve body, includes an atmospheric valve seat which advances and retreats together with the plunger, a vacuum valve seat assembled to the valve body to advance and retreat, and a valve member having an atmospheric valve portion which forms an atmospheric valve in cooperation with the atmospheric valve seat and a vacuum valve portion which forms a vacuum valve in cooperation with the vacuum valve seat. The stepped pin is pushed rearward when a corresponding portion of the rear surface of the reaction member deforms and bulges rearward, and pushes the vacuum valve seat rearward in relation to the valve body.

Abstract: A vehicle brake system, capable of realizing a brake-by-wire construction which can be installed in vehicles in the same manner as conventional brake systems, is provided with a booster device, a master cylinder, wheel brakes, and a hydraulic pressure control device interposed between the master cylinder and the wheel brakes. The system is further provided with a stroke sensor for detecting the moving stroke of a brake pedal, a simulator for applying to the brake pedal a pseudo reaction force corresponding to the moving stroke of the brake pedal, a play or idling component arranged between the booster device and the hydraulic pressure control device for absorbing the moving stroke of the brake pedal by a predetermined amount, and an electronic control device for controlling the hydraulic pressure control device based on an input from the stroke sensor.

Abstract: In a vacuum type booster device, when the advance of an input member causes an atmosphere valve seat to be separated from an atmosphere valve to advance a power piston, the position of a vacuum valve seat is moved backward relative to the power piston by a distance to which the advance amount of the power piston relative to a housing is decreased at a predetermined ratio. Thus, when a slight advance of the input member causes the atmosphere valve seat to be separated from the atmosphere valve to advance the power piston relative to the housing, the vacuum valve seat is retracted relative to the power piston and is advanced by a distance which is obtained by subtracting a retraction amount of the atmosphere valve seat from the advance amount of the power piston relative to the housing, whereby a valve mechanism of the construction as aforementioned can be closed again with the advance of the power piston.

Abstract: A combined service and parking brake apparatus includes a piston which forms a hydraulic chamber within a cylinder portion; a brake lining which, when pressed by the piston, brakes rotation of a disc rotor; a second piston which divides the hydraulic changer into a first hydraulic chamber and a second hydraulic chamber; a friction clutch which allows rotation of the second piston when the second piston is held at its home position and which disables rotation of the second piston when the second piston moves by a predetermined distance toward the second hydraulic chamber; an adjuster including an internal-thread portion and an external-thread portion and adapted to adjust the clearance between the pistons in accordance with the amount of wear of the brake lining; and a changeover valve for establishing and shutting off the communication between the first hydraulic chamber and the second hydraulic chamber.

Abstract: In a vacuum type booster device, when the advance of an input member causes an atmosphere valve seat to be separated from an atmosphere valve to advance a power piston, the position of a vacuum valve seat is moved backward relative to the power piston by a distance to which the advance amount of the power piston relative to a housing is decreased at a predetermined ratio. Thus, when a slight advance of the input member causes the atmosphere valve seat to be separated from the atmosphere valve to advance the power piston relative to the housing, the vacuum valve seat is retracted relative to the power piston and is advanced by a distance which is obtained by subtracting a retraction amount of the atmosphere valve seat from the advance amount of the power piston relative to the housing, whereby a valve mechanism of the construction as aforementioned can be closed again with the advance of the power piston.

Abstract: In a vacuum type brake booster, the reaction of output transmitted from an output shaft to a reaction member is transmitted to a valve body, a plunger, and a stepped pin. A valve mechanism, which is assembled to an axial hole of the valve body, includes an atmospheric valve seat which advances and retreats together with the plunger, a vacuum valve seat assembled to the valve body to advance and retreat, and a valve member having an atmospheric valve portion which forms an atmospheric valve in cooperation with the atmospheric valve seat and a vacuum valve portion which forms a vacuum valve in cooperation with the vacuum valve seat. The stepped pin is pushed rearward when a corresponding portion of the rear surface of the reaction member deforms and bulges rearward, and pushes the vacuum valve seat rearward in relation to the valve body.

Abstract: In a brake apparatus, a lead in a meshed portion between an external-thread portion (second stationary screw element) of a threaded shaft and an internal-thread portion (second movable screw element) of a nut is shorter than that in a meshed portion between an internal-thread portion (first stationary screw element) of a cylinder and an external-thread portion (first movable screw element) of a second piston. Accordingly, as the second piston and the nut move toward a control chamber while rotating in a unitary condition via a friction clutch, the second piston and the nut are united via the friction clutch, so that a contact portion between the thread surface of the second stationary screw element and the thread surface of the second movable screw element and a contact portion between the thread surface of the first stationary screw element and the thread surface of the first movable screw element push out against each other.

Abstract: In a brake apparatus, a lead in a meshed portion between an external-thread portion (second stationary screw element) of a threaded shaft and an internal-thread portion (second movable screw element) of a nut is shorter than that in a meshed portion between an internal-thread portion (first stationary screw element) of a cylinder and an external-thread portion (first movable screw element) of a second piston. Accordingly, as the second piston and the nut move toward a control chamber while rotating in a unitary condition via a friction clutch, the second piston and the nut are united via the friction clutch, so that a contact portion between the thread surface of the second stationary screw element and the thread surface of the second movable screw element and a contact portion between the thread surface of the first stationary screw element and the thread surface of the first movable screw element push out against each other.

Abstract: A brake hydraulic pressure generator is proposed in which the brake stroke fluctuate less when the amount of brake fluid consumed in the wheel brakes fluctuates. Even when the brake pedal force is increased after the brake assisting force has reached its maximum, the reaction force to the pedal force as well as the master cylinder pressure increases corresponding to the increased pedal force. The brake hydraulic pressure generator has a control valve including a spool and a cylinder and adapted to control the hydraulic pressure in a dynamic pressure chamber to a value corresponding to the stroke of an input shaft. It further includes a pressure sensor, a solenoid valve and a fluid chamber.

Abstract: A combined service and parking brake apparatus includes a piston which forms a hydraulic chamber within a cylinder portion; a brake lining which, when pressed by the piston, brakes rotation of a disc rotor; a second piston which divides the hydraulic changer into a first hydraulic chamber and a second hydraulic chamber; a friction clutch which allows rotation of the second piston when the second piston is held at its home position and which disables rotation of the second piston when the second piston moves by a predetermined distance toward the second hydraulic chamber; an adjuster including an internal-thread portion and an external-thread portion and adapted to adjust the clearance between the pistons in accordance with the amount of wear of the brake lining; and a changeover valve for establishing and shutting off the communication between the first hydraulic chamber and the second hydraulic chamber.

Abstract: A negative pressure type brake hydraulic pressure generating device is proposed in which the stroke on the operating side can be set independently of the stroke on the output side. A slide resistance imparting means is provided between the fixed shell and a piston having a built-in control valve introducing atmospheric air to cancel the slide resistance which is the cause of increased stroke hysteresis of the piston, i.e. the slide resistance applied to the piston at airtight seal portions between the power plate and the piston.