Abstract: In an electrically actuatable disc brake, rotation of a rotor of an electric motor is reduced by means of a differential reduction mechanism. A ball ramp mechanism is operated to press brake pads against a disc rotor to generate a braking force. In the differential reduction mechanism, when an eccentric shaft of the rotor is subjected to eccentric rotation, an external gear member having external input teeth meshing with a fixed ring gear performs an orbital motion while rotating on a center axis of the gear member, whereby a set of external output teeth of the gear member performs an orbital motion while rotating on the center axis to operate a ring gear integrally formed with a rotary disc of the ball ramp mechanism. A high reduction ratio can be easily obtained. The differential reduction mechanism can be easily formed and imparted with sufficient strength.
Abstract: There is provided a pneumatic booster having an ejector, which achieves space-saving and enables easy piping. An ejector 4 is provided within a constant-pressure chamber 3 formed in an outer shell 2. A connecting pipe 19 communicated with an outlet of a diffuser and a connecting pipe communicated with an inlet of a nozzle extend outward of the shell, and a suction port is open to the inside of the constant-pressure chamber 3 through a check valve. The connecting pipe 19 is communicated with the constant-pressure chamber 3 through a check valve 10, and is connected to a suction pipe of an engine (a source of a negative pressure). The connecting pipe on the inlet side of the nozzle is connected to an air cleaner (the atmosphere). A negative pressure is directly supplied from the connecting pipe 19 to the constant-pressure chamber 3 through the check valve 10. The ejector 4 is operated to supply a high degree of vacuum to the constant-pressure chamber 3 through the suction port.
Abstract: A piston having a piston rod connected thereto is slidably fitted in a cylinder in which a hydraulic fluid is sealably contained. Extension-stroke and compression-stroke pilot type damping force control mechanisms are provided in the piston. Check valves are provided at inlet openings of back-pressure chambers (pilot chambers). Relief valves provided in the pilot chambers include orifice passages. When the direction of stroke of the piston rod is reversed, the pressures in the back-pressure chambers are maintained due to the check valves, and the back-pressure chambers are pressurized to a satisfactory level through the orifice passages.
Abstract: An electrically operated disc brake includes a ball/ramp mechanism operable to convert rotary motion of an electric motor to linear motion and transmit the linear motion to a piston so that the piston is advanced to urge a pair of friction pads against opposite sides of a disc rotor to produce a barking force. The disc brake also includes a pad wear adjusting mechanism operable to threadably move the piston relative to an axially movable member of the ball/ramp mechanism in response to the amount of pad wear. The axially movable member has a female thread along its full length. The piston includes a piston head and a piston rod joined to the piston head. The piston rod has a male thread or threaded section. The threaded section has a length such that the piston can safely be moved together and relative to the axially movable member. The piston also has a smooth section extending from the threaded section toward the disc rotor.
Abstract: A master cylinder that can sufficiently compensate for an ineffective fluid amount at an initial stage of a stroke, even at a time of sudden braking in a case where a hydraulic control unit is disposed between the master cylinder and a brake device, is provided. The master cylinder includes a control valve that releases hydraulic pressure in a large diameter pressurizing chamber to a reservoir side when the hydraulic pressure in the large diameter pressurizing chamber reaches a fluid-release pressure corresponding to hydraulic pressure introduced via a branched flow path that branches from a communication flow path that connects a hydraulic control unit and a small diameter hydraulic chamber. A restrictor is disposed in the branched flow path for introducing the hydraulic pressure to the control valve.
Abstract: A piston connected to a piston rod is slidably fitted in a cylinder having a hydraulic fluid sealed therein. First and second poppet valves having different valve opening characteristics are provided in first and second extension main passages, respectively. A pilot control valve is provided in a sub-passage. The control pressure of the pilot control valve is adjusted by a proportional solenoid, thereby controlling damping force. At the same time, the pressure at the upstream side of the pilot control valve is introduced into back-pressure chambers to adjust the valve opening pressures of the first and second poppet valves. Because the first and second poppet valves are sequentially opened or closed, damping force can be controlled stepwisely, and ideal damping force characteristics can be obtained.
Abstract: The present invention provides a disc brake with an integral parking brake, in which a push rod, a push rod biasing member and a spring cover are formed into an assembly in the form of a single cartridge. The push rod is divided into two separate bodies, namely, a front body portion threadably engaged with a clutch member and a rear body portion engaged with a cam rod. In this disc brake, it is possible to prevent a loss of an output force of a piston under a high fluid pressure. There is no need to increase a diameter of a piston for compensating for such a loss of an output force of a piston, and a reduction in size of a disc brake can be achieved.
Abstract: An object of the present invention is to provide an electric disc brake apparatus having a simple constitution in which the operating condition of a parking brake can be reliably detected. A controller detects the operating condition (steps S25, S26) of a solenoid for driving a parking brake locking mechanism (holding mechanism) by means of a motor current (step S24). As a result, a state in which thrust generated by the motor (first electric actuator) is maintained by the parking brake locking mechanism, and accordingly the operative and inoperative states of the parking brake can be understood easily. Further, detection of the motor current is performed using a current sensor that is also used to realize a function of the motor (a function for moving brake pads toward a disc rotor), and hence separate current detection means need not be provided.
Abstract: Inner peripheral projections are provided on the inner peripheral surface of a wrap portion of an orbiting scroll member, and outer peripheral projections are provided on the outer peripheral surface of the wrap portion. The inner and outer peripheral projections each have an approximately triangular transverse sectional configuration defined by a narrow top of the projection and a pair of concavely arcuate surfaces extending with a wide overall width so that the projections can prevent stress concentration with the concavely arcuate surfaces to increase the mechanical strength and can be readily machined by using a tool, e.g. an end mill. When contacting the mating wrap portion, the narrow tops of the projections are readily crushed or worn. Therefore, the tops of the projections can become fit to the wrap portion without strongly contacting it many times.
Abstract: One of brake pads 5 is pressed against the disc rotor D by a piston of a caliper 3 which is floatably supported on the carrier 2, and in reaction thereto, the other brake pad 5 is pressed against the disc rotor D by a claw portion 14 on the caliper 3, thereby producing a braking force. During brake release, the spring force of a return spring 22 separates the brake pad 5 from the disc rotor D. A positioning convex portion 27 is provided on the carrier 2 in a standing position adjacent to the return spring 22, and serves to restrict the sideward movement of the distal end portion of the return spring 22. Thus displacement and deformation of the return spring can be prevented, and its functions can be maintained.
February 13, 2004
October 7, 2004
Harumi Ooshima, Jun Watanabe, Junichi Hashimoto
Abstract: An ejector can obtain a sufficiently large suction air quantity without reducing the ultimate vacuum. A diffuser is disposed downstream of a nozzle to form a single Laval nozzle. A suction port is provided between the nozzle and the diffuser. The inlet of the diffuser is enlarged in width so that the side walls thereof extend approximately parallel to each other along the axis of the diffuser over a predetermined length. When air is caused to flow from an inlet closer to the nozzle toward an outlet by the engine intake negative pressure, the flow velocity at a throat portion reaches the sound velocity owing to the effect of the Laval nozzle. Consequently, a high negative pressure is generated at the suction port. The parallel portion formed by enlarging the inlet of the diffuser allows the suction air quantity to be increased without reducing the effect of the Laval nozzle.
July 3, 2002
Date of Patent:
September 28, 2004
Junichi Ikeda, Atsuya Koshu, Jun Watanabe
Abstract: A piston having a piston rod connected thereto is slidably fitted in a cylinder in which a hydraulic fluid is sealably contained. Extension-stroke and compression-stroke pilot type damping force control mechanisms are provided in the piston. A pilot control valve of the extension-stroke pilot type damping force control mechanism is formed by a pressure control valve having a valve seat, a valve body and a pressure-receiving portion. A pilot control valve of the compression-stroke pilot type damping force control mechanism is formed by a flow rate control valve having a spool. A slider having the valve body of the pressure control valve and the spool of the flow rate control valve is operated by a proportional solenoid, to thereby control a damping force for an extension stroke and a damping force for a compression stroke.
Abstract: A damping force control type hydraulic shock absorber includes a plunger having a small-diameter main body portion slidably guided by a first fixed core made of a magnetic material. The plunger has a large-diameter attracted portion at an end thereof closer to a second fixed core. The diameter (D2) of the attracted portion is set larger than the diameter (D1) of the main body portion (D2>D1), thereby increasing the area of the mutually opposing surfaces of the attracted portion and the second fixed core. Accordingly, attraction force acting on the attracted portion can be increased without reducing the magnetic flux density at the main body portion.
Abstract: In a cylinder apparatus such as a hydraulic shock absorber, a piston to which a piston rod is connected slidably is inserted into a cylinder which contains liquid oil. A rebound spring is wound around the piston rod with one end of the piston rod fixed to the piston rod using a spring holder. The rebound spring is slidably guided along the piston rod by means of another spring holder. A rebound stopper is fixed to the piston rod at a position between the spring holders. The rebound spring exerts a spring force opposite to the extension of the piston rod, thereby to moderate shock at the end of the stroke of the piston. Because the spring holder comes into contact with the rebound stopper, contact of adjacent linear portions of the rebound spring with each other due to excessive compression of the rebound spring can be prevented, and also occurrence of strange noise and damage of the rebound spring can be prevented.
Abstract: A master cylinder of the invention supplies a brake fluid from a large diameter pressurizing chamber 56 to a small diameter hydraulic chamber 49 by opening a reverse flow checking opening and closing portion 61 by sliding movement of a stepped piston 16 forwardly, that is, fast fill and when the hydraulic pressure of the large diameter pressurizing chamber 56 rises, a control valve 86 escapes the hydraulic pressure of the large diameter pressurizing chamber 56 to a reservoir 12 to gradually lower in accordance with rise of the hydraulic pressure of the small diameter hydraulic chamber 49, thereby capable of reducing a strange feeling in a pedal feeling caused by sudden pressure release of the large diameter pressuring chamber 56.
Abstract: In a suspension control system, a controller previously stores damping force maps (an ordinary road map, a rough road map, and an extremely rough road map) corresponding to road surface conditions (an ordinary road, a rough road, and an extremely rough road) defined by frequency and amplitude of vertical acceleration. The frequency and amplitude of the vertical acceleration are detected, and a damping force map (the ordinary road map, the rough road map, or the extremely rough road map) corresponding to the detected information is selected. Damping force control is effected on the basis of the selected damping force map. Selection of a damping force map according to the frequency and amplitude of the vertical acceleration is also made when a change in the vertical acceleration, i.e. a change in piston speed, is predicted during running on an ordinary road, a rough road or an extremely rough road.
Abstract: A tandem pneumatic booster includes a front shell having a relatively long cylindrical portion and a rear shell having a relatively short cylindrical portion. The cylindrical portions of the front and rear shells are joined together to form a shell body. An opening edge of a cylindrical portion of a center shell is disposed in the joint between the front and rear shells, together with an outer peripheral bead of a diaphragm of a rear power piston. The cylindrical portion of each of the front, rear and center shells has a frusto-conical shape gradually increasing in diameter toward the opening edge thereof. Thus, when front shells, rear shells and center shells are stacked on one another, respectively, as constituent parts before assembly, the depth of fitting between each pair of adjacent shell elements is increased sufficiently to stably maintain the stacked conditions of the shell elements.
Abstract: There is disclosed a pneumatic booster having a vacuum chamber connected to an intake pipe of an engine. An air outlet of an ejector is connected to the intake pipe through a vacuum control valve, and an air inlet of the ejector is connected to an air cleaner. A vacuum pick-up port of the ejector is connected to the vacuum chamber of a booster body. The vacuum control valve comprises a control chamber and a control piston, and the negative pressure in the booster is introduced into the control chamber and acts on the control piston. When the negative pressure in the booster is insufficient, the control piston acts to open the control valve and a negative pressure is supplied from the ejector to the vacuum chamber. When the negative pressure in the booster is sufficiently high, the control piston acts to close the control valve and stops the operation of the ejector, thus reducing an effect of the ejector with respect to an air/fuel ratio of the engine.
Abstract: A rod guide is press-filted to an inner periphery of an outer cylinder and to an inner periphery of an inner cylinder. A rod seal is provided at an inner periphery of a cover member for covering the outer cylinder to seal between a piston rod and the cover member. Space between the rod seal and the rod guide is formed as a hydraulic fluid reservoir chamber. Further, a lip seal is integrally formed on an outer periphery of the rod seal. The lip seal is set so as to separably abut a valve seat surface of the rod guide. One side surface of the lip seal is provided with a plurality of radially extending hydraulic fluid grooves spaced from each other in a circumferential direction. With this arrangement, a valve opening pressure of the lip seal can be kept small regardless of size of interference of the lip seal. Thus, air removability is improved.
Abstract: A protective boot having a bellows portion, a cylindrical portion, a guide-bore-side mounting portion, a thick-walled portion, a thin-walled portion, a pin-side mounting portion and an air passage groove. In an operation for mounting of the protective boot, the pin-side mounting portion is inclined radially inward through the thin-walled portion while being slidably moved along the sliding pin, to thereby effect an escape of air contained in an annular space between the sliding pin and the boot through the air passage groove. The thick-walled portion prevents the pin-side mounting portion from bending radially inward to an undesirable extent. Thus, the operation for mounting of the protective boot can be smoothly conducted.