Abstract: A snap-action diaphragm having an electrically conducting central portion is electrically insulated inside a case to separate it into two parts each of which is ported to a fluid, and is biased by an electrically conducting spring towards one port which serves as an electrical contact to form a switch with the diaphragm when connected to an external circuit. The snap-action characteristic of the diaphragm between two stable states when coacting with the biasing force of the spring provides a hysteresis force that can be predetermined to avoid hunting of the switch in response to anticipated alterations in pressure difference across the diaphragm. In another embodiment, the diaphragm also acts to open or shut a valve to control fluid flow, again with the benefit of hysteresis to prevent hunting during operation.

Abstract: A D.C. charging and starter circuit for a vehicle includes a microcomputer which monitors the state of battery switch units, a pair of charging generators and a starter switch, and operates to control various switching elements and the like to prevent accidental discharge of the batteries, and to prevent damage to either the electrical load or the generator rectifier circuits.

Abstract: A pressure control apparatus, which can be used for a braking force magnification apparatus for a vehicle or a door closing and opening apparatus includes a sensor for sensing a pressure within a vacuum booster. The sensor is of a transfer-contact-type including a medial movable contact and two stationary contacts. The movable contact makes contact with one of the stationary contacts connected to an alarm lamp but breaks contact with the other connected through a control circuit to a DC motor connected to a vacuum pump or a compressor when the absolute gauge pressure produced by the vacuum pump or compressor is below a first predetermined threshold value. The movable contact breaks contact with the one stationary contact to energize the DC motor when the absolute gauge pressure is below a second predetermined threshold value but is above the first one.

Abstract: The present invention relates to a power supply system for vehicles having a generator which includes an armature coil for generating three-phase alternating current, a field coil held in opposition to the armature coil, a rectifier for converting an A.C. output of the armature coil into a direct current, and a voltage regulator for setting the generated voltage of the armature coil at a constant value by controlling a current flowing through the field coil, and a first battery which is connected across output terminals of the generator; a starting motor and an electric load connected in parallel with the first battery; and consists of a two-battery power supply system for vehicles comprising a second battery which is connected to an ignition device separately from said first battery, and which is charged by a power source other than said generator.

Abstract: A vehicular charging and starting system is improved by providing first and second a.c. generators, rectifiers and voltage regulators, the negative terminal of the first rectifier and the positive terminal of the second rectifier being connected to a neutral or body grounded conductor. A pair of batteries are respectively positively and negatively connected to said neutral or grounded conductor. Protection circuits may be provided for overcurrent protection of the rectifiers or electrical loads, and for preventing the starter motor from rotating at an excessive speed once the engine is started.

Abstract: A pump control system has a vacuum pump driven by a DC motor to supply a negative pressure to a container first power and driving transistors which are interconnected to energize the DC motor, second power and driving transistors which are interconnected to turn an alarm lamp on, and a pressure sensor having a set of normally closed contacts which are connected to the first driving transistor and which are connected via a Zener diode to the second driving transistor; the contacts opened by at least a predetermined negative pressure within the container so as to immediately turn the first power transistor off and so as the second power transistor off with a time delay as determined by a parallel combination of a capacitor and a resistor connected to the Zener diode.

Abstract: Disclosed is a control for a pumping device in vehicle application in which, upon throwing a power switch (6) and closing a brake actuator switch (8), a second driver transistor (76) is rendered conductive and a first driver transistor (75) non-conductive, thereby rendering a power transistor (71) conductive. The power transistor in the conductive state enables a DC motor (2) to be supplied with a DC voltage from batteries (5). The DC motor drives a pump (1) which in turn feeds a pressure to activate a pressure-operating unit (10). A pressure detecting switch (4) detects the pressure of the pump and particularly provides a pressure detection signal when the pressure reaches a predetermined value. In response to the pressure detection signal the first driver transistor becomes non-conductive and the power transistor becomes conductive, thus supplying the DC voltage to the DC motor.

Abstract: Disclosed is a control for a pumping device in a vehicle application in which, upon throwing a power switch (6), a capacitor (85) is charged and a power transistor (81) is rendered conductive thereby supplying a DC voltage from batteries (5) to a DC motor (2). The DC motor drives a pump (1) which in turn feeds pressure to a pressure-operating unit (10) for storage therein. If a given period of time has elapsed after throwing of the power switch, then the voltage charged on the capacitor increases to make a transistor (83) conductive and the power transistor (81) non-conductive. In other words, the DC motor is operated to provide pressure to the pressure-operating unit for only the given period of time after throwing of the power switch. Furthermore, upon closure of a brake actuator switch (4) another transistor (84) becomes conductive and the above transistor (83) becomes non-conductive. This renders the power transistor (81) conductive and supplies the DC voltage to the DC motor.

Abstract: In a diaphragm apparatus, such as a switch having a diaphragm to be driven by a pressure difference between two spaces, an iron disk is fixed to the center of the diaphragm and a ring-shaped permanent magnet is fixed to an inside wall of a case to magnetically attract the iron disk. This provides hysteresis in the force-motion characteristic of the diaphragm to reduce hunting.

Abstract: A pressure sustaining apparatus which can be used for a braking force magnification apparatus for a vehicle includes a control circuit which energizes a DC motor and a vacuum pump or a compressor associated with the DC motor. When the absolute value of the gauge pressure generated by the pump or compressor reaches a predetermined threshold pressure, a sensor detects this condition and opens its contacts in response thereto. The contacts are connected to the control circuit which electrically energizes the DC motor for a predetermined length of time after the contacts of the sensor are opened. The predetermined length of time is determined by a time constant of a timer circuit included in the control circuit.

Abstract: Disclosed is a control for pumping devices in vehicle application. Upon closure of a brake actuator switch (4) subsequent to actuation of a power switch (6) a power transistor (81) becomes conductive and a DC voltage from batteries (5) is fed to a DC motor (2). The brake actuator switch when brought into an open position permits supply of the DC voltage to the base of the power transistor through a time constant circuit (85, 86) for a limited period of time, so that the power transistor becomes conductive to supply the DC voltage to the DC motor for that period. The DC motor activates a pump (1) which in turn operates a pressure-operating unit (10).

Abstract: A control device for a vacuum pump apparatus in which a hunting effect is substantially eliminated. A pressure-sensitive switch senses a negative pressure produced by a vacuum pump, the latter being driven by a d.c. motor. The switch has at least three contacts, the positions of which are changed at two different pressures. The output of the switch is compared with a fixed reference value, and the comparison result used to drive the d.c. motor. The d.c. motor is thus provided with hysteretic drive characteristic, thereby maintaining the vacuum pressure between the two predetermined values and eliminating the hunting effect.

Abstract: An alternating current (AC) generator of the type used in vehicular applications and driven by the vehicle engine has a stator winding and a field winding wherein the electrical resistance of the field winding varies as a function of temperature. An exciting current intermittently is allowed to flow through the field winding which induces a current in the stator winding. The output of the stator is rectified and used to charge the vehicle battery. The invention comprises inclusion of field winding current compensation apparatus which varies as a function of temperature to reduce undesired field winding current variations due to temperature which results in improvements of power output and stabilized generator driving torque.

Abstract: A vehicular generator with at least one cooling fan, wherein a plurality of blades of the cooling fan are made of a shape memorizing alloy, whereby, especially in medium and high revolution speed operations and low electric loads in which cooling air is not required, the blades are flattened, thereby preventing the rotational efficiency of the generator from falling and reducing noise ascribable to the cooling fan.

Abstract: The present invention relates to a charging generator control system comprising a generator which includes a field winding, and an armature winding being in three-phase connection to generate an A.C. output; a rectifier which rectifies the A.C. output from said armature winding of said generator; a battery which is charged with a D.C. output from said rectifier and which can supply an exciting current to said field winding; a separately-exciting power source which generates a D.C.