Hitachi, Ltd.

Hitachi Automotive Systems, Ltd.

Takayuki Ohno

Takuya Obata

Daisuke Yasukawa

Makoto Nishimura

Yukio Ohtani

Hirofumi Watanabe

Toshiyuki Innami

Junichi Ikeda

Kimio Nishino

Hirotaka Oikawa

Norikazu Matsuzaki

Masayuki Kikawa

Toshio Takayama

Kenji Kikuchi

Naoki Shirakawa

Hirohumi Watanabe

Makoto Tajima

Naoki Ishibashi

Yu Ishimaru

A stopper mechanism includes a second cylinder provided at an end portion in an inner cylinder, and a second piston configured to move along with movement of a piston rod to be capable of being fit-inserted through the second cylinder. The second piston includes a stopper coupled to the piston rod, a castle integrated with the stopper by plastic flow to form a ring groove on an outer periphery of the second piston between the castle and the stopper, and a piston ring fixed into a ring groove formed by the stopper and the castle so that the piston ring is displaceable in the ring groove in an axial direction and is retained in the ring groove, and has an annular shape with both ends in a circumferential direction which are formed by partially cutting the piston ring.

Cylinder device

A fastening method for fastening a nut to a bolt by screwing includes preparing a nut including a tool mounting portion formed on a seat surface, and an annular thin portion formed on the tool mounting portion opposite to the seat surface, swaging a plurality of places of the thin portion with punches from an outer circumferential direction, and flowing a thickness of the thin portion so as to extend to a front end of the bolt partially in a circumferential direction to be closely adhered to a screw portion of the bolt.

Fastening method and cylinder device

A shock absorber includes a cylinder sealingly containing oil, and a piston coupled with a piston rod and inserted in the cylinder. The shock absorber generates a damping force by controlling an oil flow generated according to a movement of the piston with use of a damping force generation mechanism. A separator tube is externally disposed around the cylinder. The oil is transmitted into the damping force generation mechanism via a branch tube integrally formed on a cylindrical sidewall of the separator tube. The branch tube is formed on the cylindrical sidewall of the separator tube by burring processing. Both sides of a proximal portion of the branch tube in a circumferential direction of the cylindrical sidewall of the separator tube are pressed from an interior to concave an inner circumferential surface radially outwardly, thereby forming recesses.

Tube provided with branch tube, shock absorber, and method for making them

Provided is a brake controller which can be made smaller. The brake controller () has a hydraulic control mechanism (), which comprises a master cylinder () which generates a hydraulic fluid pressure on the basis of an input piston () and a control piston () that move when a braking operation is performed, motors (), and a moving mechanism () which moves the aforementioned control piston as the aforementioned motors turn, and a motor control unit () for regulating the turning of the aforementioned motors. The brake controller is characterized in that the aforementioned motor control unit () has a metal case () with a built-in control circuit, the aforementioned metal case () is affixed to the housing () of the aforementioned moving mechanism (), one end of the aforementioned case () is placed at approximately the same position as an end of the aforementioned moving mechanism () in the axial direction of the aforementioned input piston (), and the other end of the aforementioned case () is placed at approximately the same position as an end of the aforementioned master cylinder ().

Brake controller

An electric booster in which a rotation of an electric motor is converted into linear motion and transmitted to an output member by a rotation-linear motion mechanism. The output member pushes a piston of a master cylinder to generate brake fluid pressure in a pressure chamber in the master cylinder. An ECU casing containing boards is coupled to the top of a motor casing constituting the electric motor. The ECU casing is offset in one direction in a plane perpendicular to a plane containing an axis of the master cylinder. A male connector is provided at a side surface of the ECU casing on the opposite side from the offset direction side, and a space between the male connector and an interference area of the ECU casing is utilized as a space for attachment/detachment of the male connector.

Electric booster

A brake control system that enables accurate brake control is provided that precisely detects a master-cylinder pressure and includes a back-up function. The brake control system includes a master-cylinder operated by a brake operation of a driver; a first mechanism that regulates a pressure inside the master-cylinder according to the brake operation amount; a first control apparatus that controls operation of the first mechanism; a second mechanism that regulates communication of the pressure inside the master-cylinder to a wheel-cylinder; and a second control apparatus that controls operation of the second mechanism and operation of a pump apparatus that increases a pressure communicated to the wheel-cylinder. The first and second control apparatuses each have a power supply circuit and CPU. The brake control system further includes a first hydraulic pressure sensor that measures a pressure inside the master-cylinder and is electrically connected to the first control apparatus, and a second hydraulic pressure sensor that measures a pressure inside the master-cylinder and is electrically connected to the second control apparatus.

Brake control system

The present invention relates to an electric booster in which a rotation of an electric motor is converted into a linear motion and transmitted to an output member by a rotation-linear motion mechanism, and the output member pushes a piston of a master cylinder to generate a brake fluid pressure in a pressure chamber in the master cylinder. The present invention is characterized in that an ECU casing containing boards and the like such as a board for controlling the electric motor is coupled to the top of a motor casing constituting the electric motor. The ECU casing is offset in one direction in a plane perpendicular to a plane containing an axis of the master cylinder. A male connector is provided at a side surface of the ECU casing on the opposite side from the offset direction F side, and a space between the male connector and an interference area of the ECU casing with the other components and devices is utilized as a space for attachment/detachment of the male connector to/from the female connector.

An electric booster according to the present invention comprises a booster piston disposed around an input piston so as to movable relative to the input piston. The booster piston and input piston also serve as a primacy piston of a tandem master cylinder. A brake fluid pressure is generated in the tandem master cylinder by an input thrust force provided from a brake pedal to the input piston and a booster thrust force provided from the electronic actuator to the booster piston. In this electric booster, a slide hole is formed through the secondary piston of the tamed master cylinder in the axial direction therefore, and a rod member is slidably disposed through the slide hole. When the fluid pressure is not increased in the primary pressure chamber, due to the fluid pressure in the secondary pressure chamber, the rod member comes to abut against the input piston, and a reactive force in the secondary pressure chamber is returned to the brake pedal.

Electrically driven brake booster and master cylinder

An electric booster which drives an electric motor () in response to a movement of an input member () moving together with a brake pedal (B), and generates a brake hydraulic pressure in a master cylinder () through a ball screw mechanism (). The electric motor () includes a stator () having a coil therein, a rotor () which rotates by applying current to the stator (), and an annular motor casing () containing the stator () and the rotor (). The ball screw mechanism () is fittedly disposed in the rotor (). An opening () on one axial end side of the motor casing () has a larger diameter than an outer diameter of the ball screw mechanism (). In manufacturing, after the electric motor () alone is tested, the ball screw mechanism () is inserted through the opening () and installed without the need of disassembling the motor casing ().

Electric booster and method for manufacturing the same

The present invention relates to an electrically driven brake booster in which boost control is performed as follows; when an input piston is displaced forward by an input rod upon an operation of a brake pedal, an electric motor is operated according to the input, and a primary piston is displaced forward by a ball-screw mechanism, and then a primary and secondary pressure chamber in a master cylinder main body are pressurized. A first seal and a second seal are disposed at a seal portion between the primary piston and the input piston. A portion between the first seal and the second seal is in communication with an outside through a discharge passage. Brake fluid which leaks from the first seal is sealed off by the second seal, and is discharged to the outside through the discharge passage, whereby it becomes possible to prevent that the electric motor and the ball-screw mechanism otherwise might be corroded by the leaking brake fluid.

Growing community of inventors

Yokohama, Japan

Takayuki Ohno