Abstract: An upper die and a lower die are combined. A core for molding a concavity and another core are combined with the combined upper die and the lower die at respective prescribed positions. A core for through-hole molding is constructed by the junction of cores that are severally formed with the upper die and the lower die integrally on the extension line of the central axis of the core for molding a concavity. A through-hole is molded with the core for through-hole molding. A concavity in which a valve mechanism is equipped and a communicating hole through which the concavity communicates with the through-hole are molded with the core for molding a concavity. The core for through-hole molding includes an impact hole, in which a tip of the core for molding a concavity is impacted.

Abstract: In a brake control method for a motorcycle which includes a front master cylinder, front wheel cylinders hydraulically connected to the front master cylinder, a rear master cylinder, a rear wheel cylinder hydraulically connected to the rear master cylinder and a hydraulic pressure pump. When only the front master cylinder is operated, brake pressure fluid is supplied to the front wheel cylinders and the fluid pressure pump is driven to supply discharging pressure fluid to the rear wheel cylinder, and when only the rear master cylinder is operated, brake pressure fluid is supplied only to the rear wheel cylinder.

Abstract: An improvement of a valve plunger 14 used in a brake booster 1. A valve plunger 14 is made up of a rearwardly disposed body 34, and an engaging member 35 mounted on a front portion of the body 34. When a brake pedal is quickly depressed during an emergency brake operation, the engaging member 35 retracts rearward relative to the body 34, whereby the axial size of the entire valve plunger 14 is reduced, thereby increasing the opening of an atmosphere valve during the emergency brake operation as compared with a normal brake operation, allowing an output of an increased magnitude to be rapidly obtained. Thus, the invention allows an output from the brake booster 1 to be rapidly increased in immediate response to a quick depression of a brake pedal.

Abstract: An automatic brake booster includes a solenoid and a solenoid plunger which allow a flow path in a valve mechanism to be switched without depression of a brake pedal. The solenoid plunger comprises a rear member on which an atmosphere valve seat is formed, a front member which is disposed to be displaceable with respect to the rear member, and a first spring disposed between the both members. When a current fed to the solenoid is less than a given value, the first spring remains inactive while when the current exceeds the given value, the first spring becomes flexed to reduce a clearance between the rear member and a holder which forms part of a magnetic path of the solenoid together with the rear member. When the booster operates as an automatic brake, a gentle brake operation which allows a precise control with a reduced brake output and a quick brake operation with an increased brake output can be simultaneously achieved in a preferred manner.

Abstract: In a brake pedal apparatus, as a brake pedal is depressed when an engaging device and a receiving portion are engaged with each other, a second lever member pivots about a second pivot pin. At this point, when the pedaling force is smaller than a threshold value, the engagement between the engaging device and the receiving portion is maintained so that the second lever member pivots about the second pivot pin. In this state, the pedal leverage is set to be a smeller ratio. As the pedaling force exceeds the threshold, the engaging device is disengaged from the receiving portion. Then, the first and second lever members are coupled by a stopper portion to pivot together about a first pivot pin. Therefore, the pedal leverage is changed to a larger ratio.

Abstract: In a fluid pressure boosting device 1 of the present invention, a control valve 4 is composed of a supply valve 44 and a discharge valve 45, the supply valve 44 comprises an annular valve cone 46 of a poppet type and a first valve seat 7 and the discharge valve 45 comprises an annular valve cone 46 of a poppet type and a second valve seat 8. Inside a rear end portion of a primary piston 21 of a master cylinder 2, a reaction disk 57 made of an elastic material such as rubber is fitted. An input shaft 3 penetrating the control valve is arranged such that, in the inoperative state, an end thereof confronts the reaction disk 57 with a predetermined space therebetween and, in the operative state, the end comes in contact with said reaction disk 57 so that a reaction force is transmitted to the input shaft 3. The passage for discharging hydraulic fluid of the power chamber 9 is composed of annular passages 52, 53.

Abstract: A master cylinder including a cylinder body having a cylindrical bore and an opening in the circumferential wall for a relief port communicating with the interior of hydraulic reservoir. A piston is slidably inserted into the cylindrical bore to form a hydraulic pressure generating chamber in the cylindrical bore. A cup seal is provided with an inner circumferential lip portion contacting with the piston, an outer circumferential lip portion slidably contacting with the inner circumferential wall of the cylindrical bore, and a base portion connecting the lip portions, which are so arranged as to face to the hydraulic pressure generating chamber. The cup seal cuts the communication between the hydraulic pressure generating chamber and the hydraulic reservoir through the relief port when the top end of the outer circumferential lip portion passes by the relief port.

Abstract: A throttle valve mechanism having a throttle function of throttling the flow of working fluid from a pressure delivering chamber to a reservoir at the operation time of the piston of a master cylinder, a valve function of allowing the working fluid to flow from the reservoir to the pressure delivering chamber by opening the valve at the return time of the piston, and a relief valve function of allowing a large quantity of working fluid to flow from the pressure delivering chamber to the reservoir is disposed in a fluid passage for connecting the master cylinder to the reservoir. The master cylinder can decrease the quantity of working fluid flowing to the reservoir at the time of operation start of the master cylinder, and can respond to the fluctuations in fluid pressure quickly when a traction control unit, an automobile stability control unit, etc. are released.

Abstract: An automatic brake booster 1 includes a solenoid 8 which causes a back- and forth movement of a solenoid plunger 31 to switch a valve mechanism 6. A second vacuum valve seat member 11 including a second vacuum valve seat 12 which is juxtaposed with a first vacuum valve seat 10 on a valve body 3 and a pressure responsive area 34 subject to a pressure of a variable pressure chamber and a pressure of a constant pressure chamber is slidably mounted on the valve body. The effect of the pressure differential acting upon the pressure responsive area is balanced with the force resulting from the excitation of the solenoid plunger 31 to deliver a brake output which corresponds to the force. The invention enables a high accuracy control of a brake output during an automatic brake operation.

Abstract: An electrically driven brake booster (1) includes an input member (4) disposed in operative association with a brake pedal (12), an output member (5) disposed in operative association with the master cylinder (6), and drive transmitting device (10) for translating a rotating motion of a motor (9) into a linear motion to be transmitted to the output member (5). The drive transmitting device (10) comprises a rack (23) formed on the output member (5), and pinions (21, 22) disposed in operative association with the motor (9) and in meshing engagement with the rack (23). Also, reaction transmitting device (8) which transmits a brake reaction to the input member (4) and the output member (5) at a given proportion is provided. In comparison to conventional drive transmitting device, the drive transmitting device (10) of the present invention has a simple construction, a reduced weight and a better transmission efficiency.

Abstract: To provide a technique capable of detecting lifting of a rear wheel of a two-wheeled vehicle correctly and rapidly. An estimated vehicle speed is generated by selecting the larger one of wheel speed Vf, Vr of a rear wheel and a front wheel, and attention is paid to an estimated vehicle deceleration which is computed based on the estimated vehicle speed and it is judged that lifting of the rear wheel has occurred when a degree of lowering of the estimated vehicle deceleration is a predetermined value or larger.

Abstract: A brake system 1 of the present invention comprises a brake operating means 2 such as a brake pedal for carrying braking operation, a fluid variable stroke means 3 which variably controls the stroke of the brake operating means 2 by using fluid, and a braking force output means 4 which is actuated by the operation of the brake operating means 2 to produce braking forces. By manipulating the brake operating means 2, the braking force output means 4 performs the braking operation. The traveling rang of the brake operating means 2 i.e. the stroke can be changed variously by the fluid variable stroke means 3 using fluid. Since the stroke of the brake pedal can be changed as mentioned above, a proper pedal stroke can be obtained.

Abstract: In a braking pressure intensifying master cylinder, as an input shaft (53) travels forwards in a braking maneuver, a control valve (54) is actuated to develop fluid pressure according to the input in a reaction chamber (38) and a pressurized chamber (35). A stepped spool (45) as a part of the control valve 54 travels such that force produced by the fluid pressure and spring force of a spring (51) are balanced, whereby the stepped spool (45) can function as a travel simulator. By changing the pressure receiving areas of the stepped spool and/or changing the spring force of the spring (51), the travel characteristic of the input shaft (53) as the input side can be freely changed independently from the output side, without influence on a master cylinder pressure as the output side of the braking pressure intensifying a master cylinder (1). In addition, the master cylinder pressure can be intensified when necessary with a simple structure.

Abstract: A first vacuum valve seat 17 is formed on a valve body 3, and a second vacuum valve seat 18 is formed on a tubular member 21 which is slidably mounted on the valve body 3. A lever member 41 is provided between the tubular member 21 and a valve plunger 14, and when the valve plunger 14 strokes through a given stroke or more relative to the valve body 3, the lever member 41 moves angularly to retract the tubular member 21 rearward relative to the valve body 3. When a brake pedal is quickly depressed, the lever member 41 moves angularly to cause an engaging tab 41f to engage an engaging recess 44 formed in the valve body 3, thus retaining the tubular member 21 at a position which is reached as it is retracted rearward relative to the valve body 3. This allows an atmosphere valve 33 to be opened to a greater opening than during a usual operation, allowing an increased output to be obtained rapidly.

Abstract: In the present invention, a throttle valve mechanism 43 having a throttle function (46b) of throttling the flow of working fluid from a pressure delivering chamber 29, 30 to a reservoir 19 at the operation time of the piston 27, 28 of a master cylinder 20, a valve function (46d) of allowing the working fluid to flow from the reservoir 19 to the pressure delivering chamber 29, 30 by opening the valve at the return time of the piston 27, 28, and a relief valve function (46c) of allowing a large quantity of working fluid to flow from the pressure delivering chamber 29, 30 to the reservoir 19 is disposed in a fluid passage for connecting the master cylinder 20 to the reservoir 19.

Abstract: To provides a technique capable of replenishing a working fluid smoothly while employing a method for replacing an atmospheric air with the working fluid. The reservoir apparatus (10) includes a main reservoir (20) having an inlet opening for feeding a hydraulic fluid, and an auxiliary reservoir (50) connecting thereto through a piping (30). There is a diagonally extending connecting pipe (60) at the auxiliary reservoir (50). There is a recessed portion (80) at an opening portion (64) of an inner periphery of the connecting pipe (60). This recessed portion (80), when compared with the case where there is no such a recessed portion, serves to enlarge the opening portion (64) of the connecting pipe (60) and more smoothly flow the replenishment working fluid at a nearby area of the opening portion (64).

Abstract: An electric control apparatus of a brake is provided with a second reservoir, in which a brake fluid is stored in advance, separately from a control device of a brake hydraulic pressure. The second reservoir communicates with a pump, which is an original component of the control device, on the side of a suction opening of the pump through a second liquid passage equipped with a first on-off valve. A first liquid passage is equipped with a second on-off valve. The pump is operated with the first on-off valve being opened to supply a brake hydraulic pressure corresponding to the quantity of an operation of a brake pedal in a sate in which the second on-off valve is closed to a wheel cylinder as an electric control mode of a brake hydraulic pressure of an electronic control unit.

Abstract: A pump including a pump chamber 18, formed in a pump body 11, between a cam ring 17 and a rotor 15. The cam ring is formed so as to move in a direction whereby the pump capacity of the pump chamber increases and decreases. First and second fluid pressure chambers 33 and 34 are formed at opposite sides of the cam ring 17. The pump has a spool that is axially moved by a difference in fluid pressure between upper and lower stream sides of a metering throttle 50 connected to a discharge side passage 27 of the pump chamber. The spool is part of a control valve 30 that controls fluid pressure in at least the first fluid pressure chamber. An electronic driving unit, for example, a solenoid 60, applies axial thrust to the spool of the control valve.

Abstract: A tubular member 21 is disposed within a valve body 6, and has a resilient retainer 69 mounted around the outer periphery thereof. The inner periphery of the valve body 6 is formed with an annular groove 68. When a brake pedal is quickly depressed, an input shaft 23 and the tubular member 21 are driven forward through more than a given stroke relative to the valve body, whereby a projection 69a of the retainer 69 becomes engaged with the annular groove 68. This produces and maintains a large opening in an atmosphere valve 32. Accordingly, an output from a tandem brake booster 1 can be increased immediately in response to a quick depression of the brake pedal.

Abstract: In a brake control method for a motorcycle which includes a front master cylinder, front wheel cylinders hydraulically connectable to the front master cylinder, a rear master cylinder, a rear wheel cylinder means hydraulically connectable to the rear master cylinder and a hydraulic pressure pump, when only the front master cylinder is operated, brake pressure fluid is supplied to the front wheel cylinders, the fluid pressure pump is driven to supply discharging pressure fluid to the rear wheel cylinder and, when only the rear master cylinder is operated, brake pressure fluid is supplied only to the rear wheel cylinder.