Abstract: A tandem brake booster includes a solenoid within a valve body, and the solenoid may be energized to move a first tubular member disposed on the valve body rearward. When an input shaft is driven forward in the inoperative condition of the brake booster, a vacuum valve is closed while an atmosphere valve is opened in the similar manner as occurs in the prior art, thus actuating the tandem brake booster 1. When an input or the force of depression applied to a brake pedal rises to a given value X during the operative condition of the brake booster, the solenoid is energized, whereupon the first tubular member is moved rearward relative to the valve body, and the valve element is also moved rearward. This opens the atmosphere valve which has been closed during the servo balance condition, allowing a further introduction of the atmosphere into variable pressure chambers B, D, enabling a rise in the output even though the input remains unchanged.

Abstract: A brake booster which permits an axial relative movement between a power piston and a valve body is disclosed. An arrangement is made which prevents a brake reaction from being transmitted to a brake pedal. As an alternative therefor, pseudo-reaction imparting means transmits a pseudo-reaction to a brake pedal. A rear end of the valve body is covered by a tubular cover and bellows connected thereto, and its internal space is maintained in communication with a constant pressure chamber. The bellows has an effective diameter which is chosen to be of an equal size to the diameters of a vacuum valve seat and an atmosphere valve seat. This allows a pseudo-reaction and a brake pedal stroke to be obtained which depend on the force with which a brake pedal is depressed if a negative pressure within the constant pressure chamber varies, thus imparting a better brake feeling to a driver.

Abstract: An automatic brake booster includes a solenoid which drives a plunger, forming part of a valve mechanism, forward to switch a flow path in the valve mechanism, separately from an input shaft. A piston is mounted on the plunger, and the atmospheric pressure is introduced into an atmospheric pressure chamber disposed forwardly of the piston while a pressure which prevails in constant pressure chambers A, C is introduced into a negative pressure chamber disposed rearwardly of the piston, thus urging the piston rearward. Preferably, the piston has a pressure responsive area which is substantially equal to the pressure responsive area of an atmosphere valve seat formed on a plunger. This arrangement allows a variation in the output from the brake booster to be minimized or reduced substantially to zero if there is a variation in the magnitude of a negative pressure which is introduced into the constant pressure chambers A, C.

Abstract: A cam case 23 is provided which swingably support a cam ring 34 fitted to a rotor 33 having a vane 33a so as to form a pump chamber 36 from the outer surface such that the cam ring 34 is swingably supported by using a swingable pin 35 disposed in the axial direction as a fulcrum, the cam case 23 serving as an intermediate body. Pump bodies are disposed on the two ends of the cam case in the axial direction. Moreover, a front body 21 and a rear body 22 for rotatively supporting a rotational shaft 40 of the rotor are disposed. A valve hole 75 for forming a relief valve 74 for relieving fluid pressure in the discharge portion of the pump to a suction portion of the pump when the fluid pressure has been made to be not lower than a predetermined level is a blind hole having an end which is, in the rear body, opened in a joining surface with the cam case. Valve elements 74a received in the valve hole are anchored by the joining surface of the cam case.

Abstract: An electrically controlled braking system allows a pedal stroke produced by an operation of a brake pedal to be detected by a stroke sensor and to be input to a controller, which in turn controls a brake pressure generated by a brake pressure generator in accordance with the magnitude of the pedal stroke. A pedal reaction unit is added to the brake pressure generator. The pedal reaction unit comprises an air cylinder connected to the brake pedal, the stroke sensor which detects the pedal stroke, and a pair of solenoid operated open/close valves for feeding the air pressure from an air tank to, or displacing the air pressure from, the air cylinder. The controller causes the air to be fed to or displaced from the air cylinder in accordance with the magnitude of the pedal stroke detected by the stroke sensor, thus producing a pedal reaction having a controlled magnitude.

Abstract: In case of reducing pressures according to an ABS of the present invention, solenoid valves 14, 15 are turned on and the pressure difference between chambers 24, 23 of a vacuum booster 4 becomes smaller, thereby reducing the brake pressures. Further, solenoid valves 7, 9 are turned on so that brake fluid in W/Cs 8 is discharged to sumps 10, thereby further reducing the brake pressures. At this point, the pressure difference between chambers 55, 56 of a vacuum driven pump 51 also becomes smaller so as to move pistons 54, 61, 62 backward and the brake fluid of the sumps 10 is thus sucked into fluid chambers 63, 64. In case of increasing pressures by the ABS control, the solenoid valves 14, 15, 7, 9 are turned off and the pressure difference between the chambers 24, 23 becomes larger, thereby increasing the brake pressures.

Abstract: A glow plug for a diesel engine includes a heat generating coil, a control coil, a sheath, an electrode rod, and a housing. The heat generating coil serves as a heater element. The control coil is connected in series with the heat generating coil and serves as a controller for controlling power supply to the heat generating coil. The control coil has a positive temperature coefficient of resistance larger than that of the heat generating coil. The sheath accommodates the heat generating coil and the control coil to be embedded in a heat-resistant insulating powder. The sheath has an elongated small-diameter portion on a distal end side thereof and a large-diameter portion on a rear end side thereof. The heat generating coil is connected to an inner wall of a distal end of the small-diameter portion of the sheath. The electrode rod has a distal end portion to which one end of the control coil is connected.

Abstract: In a brake system, when a braking force tends to be insufficient, a first switching valve is set at an interrupting position to render a control chamber in a sealed state, and a pump is actuated to render a supplemental pressure-regulating valve in operation. Thus, MCY pressure supplied to a port of the supplemental pressure-regulating valve is increased to move a supplemental pressure piston downwardly to close the supplemental pressure-regulating valve. The fluid pressure from the pump is supplied to a brake cylinder to increase the braking force. In this manner, a supplemental braking control is provided to ensure the braking even when the braking force tends to be insufficient. The system can be made simple.

Abstract: A ceramic heater includes a heating element and a sintered body. The heating element is formed of a material containing one of a refractory metal having a melting point of 2,000.degree. C. or more, and a material including an inorganic conductive material. The sintered body of an insulating ceramics contains one of silicon nitride and silicon carbide materials. The heating element is buried in the sintered body. The insulating ceramics contains at least one kind of nitrides of Groups IIIA, IVA, and VA in the element periodic table at a ratio of 0.01 vol % to 10 vol %. A method of manufacturing the ceramic heater is also disclosed.

Abstract: A rack-pinion type power steering apparatus includes a cylindrical stub shaft, a torsion bar, a pinion shaft, a rotor, and a sleeve. The stub shaft rotates in a steering body upon a steering operation. The torsion bar has one end fixed at one end of the stub shaft and extends through the stub shaft toward the other end of the stub shaft. The pinion shaft is pivotally connected to the other end of the torsion bar. The rotor is arranged to cover the torsion bar from the stub shaft along an extending direction of the torsion bar. The sleeve has one end integrally connected to the pinion shaft, extends from the pinion shaft along the stub shaft, and is arranged around the rotor to constitute a rotary type channel selector valve between the rotor and the sleeve. The pinion shaft is axially supported by the steering body at two end portions of the sleeve.

Abstract: A method is provided for controlling an electric power pump type power steering system.

Abstract: A plurality of axially extending ribs are formed in the inner periphery of a valve body at its front end for slidably supporting the outer peripheral surface of the output shaft at its rear end. With this arrangement, any dimensional error which may occur in the region of the ribs can be suppressed small during the manufacturing of the valve body if a diameter shrinkage occurs in the inner periphery thereof. Accordingly, when the rear end of the output shaft is slidably fitted into the ribs, the output shaft is less likely to be askew with respect to the axis of the valve body. Accordingly, a biased abrasion of an annular seal member which is disposed between an opening formed in the front portion of a shell and the outer periphery of the output shaft at its front end to maintain a hermetic seal therebetween can be suppressed.

Abstract: In accordance with the invention, a booster is not provided with a mechanism which transmits a braking reaction, and accordingly, a reaction cannot be transmitted to a brake pedal. On the other hand, a pseudo-reaction imparting means is provided to impart a pseudo-reaction which depends on an amount of depression of the brake pedal. The pseudo-reaction imparting means imparts a pseudo-reaction having a reduced rate of increase to the brake pedal when a travel of the brake pedal is small, and imparts a pseudo-reaction having an increased rate of increase to the brake pedal when a travel of the break pedal is higher. This arrangement avoids the drawback of the prior art that an abnormally high braking reaction is transmitted to a driver as a result of an operational lag of a conventional booster during a quick braking operation.

Abstract: The present invention provides a brake fluid pressure control valve having a plunger 23 slidably fitted in a cylinder hole 22 in a cylinder housing 21 and a retainer 24 which holds the posture of the plunger 23 and seals one end of the cylinder hole 22 by using an O-ring 31 serving as a sealing member, the control valve being characterized in that the plunger 23 is formed with a step 27a, the cylinder housing 21 is provided with an engagement hole 29, which engages with the step 27a and is formed in the direction crossing with respect to the plunger 23, and a pin 30 is inserted in the engagement hole 29 so that the plunger 23 is prevented from coming off by the pin 30. Further, the engagement hole 29 is also used as an air bleeding path adjacent to an installation hole for an air bleeder 40.

Abstract: An equalizer 26 is interposed between a load detecting lever 22 and one end of each plunger 3, 4, a clamp member 23 is provided to position the equalizer at a predetermined position of the load detecting lever 22, a connecting portion rotatably connected to a housing 2 concentrically with respect to a support portion 2a supporting the load detecting lever 22 is provided on the clamp member, an arm 24 is formed at the connecting portion of the clamp member 23, and the arm 24 is supported by the support portion 2a of the housing 2 by using a pin 27 common to the load detecting lever 22.

Abstract: In a brake booster system of the present invention, just after a MCY produces MCY pressure Pi according to the pedal pressure of a brake pedal, a valve piston of a pressure-intensifying valve moves so that a valve portion is seated in a rubber valve seat. In addition, a pedal switch detects the pedaling of the brake pedal to drive a motor and a pressure-intensifying pump. Therefore, W/C pressure Po of a W/C is intensified by the discharge pressure of the pressure-intensifying pump. The intensified W/C pressure Po causes the upward movement of a stepped piston of a pedal stroke shortening cylinder. The brake fluid is transferred toward the MCY corresponding to the movement of the stepped piston, thereby restricting the stroke of the piston of the MCY and thus shortening the pedal stroke of the brake pedal.

Abstract: A rubber damper is disposed between a valve plunger, which forms a valve mechanism of a brake booster, and a plate plunger. An air gap is defined around the outer and the inner periphery of the rubber damper to permit an elastic deformation of the rubber damper. When a brake pedal is further depressed under a servo balance condition, the valve plunger compresses the rubber damper, whereby it is driven forward. This arrangement allows a force of depression required when the brake pedal is further depressed under the servo balance condition to be reduced relative to the force of depression required in a conventional arrangement in which the valve plunger must be driven forward by compressing a reaction disc which is surrounded by an output shaft, a valve body and a valve plunger. As a consequence, the response of the brake booster is improved.

Abstract: To join at least two metal members a connecting member made of a green ceramic body or ceramic sintered body having connecting a hole formed therein is used. After at least the two metal members are inserted in the hole of the connecting member to overlap their joining ends, they are sintered.

Abstract: An object of the present invention is to provide a master cylinder which decreases the number of necessary parts, achieves easy assembly and stabilized quality, and surely prevents a float from coming off. In the present invention, the master cylinder tank 20 contains working fluid in the interior of a tank body 21 and incorporates a float 25 movable vertically in response to the increase and decrease in the working fluid by being guided by a float guide 22, and coming-off preventive portions 24, 24, capable of being deformed elastically, are provided to cover at least a part of the float 25 by extending a part of the float guide 22 upward beyond a guide rib 23. The coming-off preventive portions 24, 24 are formed by being bent to the inside into a shape such as to partially cover the float 25, so that the float 25 is prevented from coming off by the coming-off preventive portions 24, 24.

Abstract: In a hydraulic boosting device of the present invention, when the pressure stored in an emergency accumulator is less than a set pressure, a stepped piston 70 moves downward, a throttle valve 72 is set in a first position where the throttle valve 72 is seated in a valve seat 71, and hydraulic fluid flowing from a pump through an inlet path 14 is restricted by a flow limiting valve 68 so as to develop a fluid pressure in an annular path 73. The fluid pressure is stored in the emergency accumulator through a path 69, an accumulator valve 27, and an accumulator path 31. When the pressure stored in the emergency accumulator exceeds the set pressure, the stepped piston 70 moves upward, the throttle valve 72 is set in a second position where the throttle valve 72 is apart from the valve seat 71, and the hydraulic fluid from the pump is not restricted by the flow limiting valve 68 at all so as to flow freely toward a control valve. In this state, no fluid pressure is developed in the annular path 73.