Abstract: A hydraulic pressure control apparatus has an electromagnetic valve having a valve body forced to one side by an elastic member and a coil driving the valve body to the other side; a hydraulic pressure control section for calculating a command current value to drive the electromagnetic valve and controlling a hydraulic pressure in a hydraulic circuit by opening/closing the electromagnetic valve; a current detection section detecting a value of the current passing through the coil; and a command current value correction section. The command current value correction section detects a change of an inductance of the coil when the valve body moves from the one side to the other side or from the other side to the one side through the current detection section, and corrects the command current value using the detected inductance change.

Abstract: A solenoid valve includes a solenoid coil, a yoke of magnetic material, an armature of magnetic material to move in an axial direction of the solenoid coil when the solenoid coil is energized, a plunger to be moved with the armature, a valve seat member including a seat portion formed with a valve hole to be closed and opened by a forward end portion of the plunger, and a coil spring which is disposed between a spring receiving portion of the plunger and the valve seat member, around the plunger. The plunger includes a pressure receiving portion (such as a flat portion) which extends in a radial direction of the plunger at a position between the forward end portion and the spring receiving portion of the plunger, and which faces to the seat portion.

Abstract: A seal apparatus includes at least one pair of gears; a side plate arranged adjacent to the pair of gears; and a housing sandwiching the side plate. At least one of the side plate and the housing includes a shoulder portion. The seal apparatus further includes a seal member arranged between the housing and the side plate and arranged at the shoulder portion. The seal member separates a low pressure area from a high pressure area in a radial direction of the gear. The shoulder portion is located in the low pressure area. At least a part of the seal member faces the high pressure area. The seal apparatus further includes a backup member reinforcing the seal member and facing a tip portion of the shoulder portion; and a containing portion formed between a root portion of the shoulder portion and the seal member to be capable of containing a part of the seal member at least when the seal member is elastically deformed.

Abstract: An external gear pump capable of achieving both a sealing property and a sliding property is disclosed. The external gear pump includes a pair of rotating shafts that are respectively pivotally supported by bearings provided in a casing; at least a pair of gears that are respectively fixed to the pair of rotating shafts and are externally meshed with each other; a side plate that is provided in sliding contact with one side surfaces of the pair of gears; and a seal block integrally including a side surface sliding part and a tooth tip sliding part. The external gear pump further includes movement restrictors on both sides of a straight line connecting axes of the pair of gears, and the movement restrictors restrict the seal block from moving with respect to the casing on a plane orthogonal to the rotating shafts.

Abstract: A hydraulic pressure control apparatus has an electromagnetic valve having a valve body forced to one side by an elastic member and a coil driving the valve body to the other side; a hydraulic pressure control section for calculating a command current value to drive the electromagnetic valve and controlling a hydraulic pressure in a hydraulic circuit by opening/closing the electromagnetic valve; a current detection section detecting a value of the current passing through the coil; and a command current value correction section. The command current value correction section detects a change of an inductance of the coil when the valve body moves from the one side to the other side or from the other side to the one side through the current detection section, and corrects the command current value using the detected inductance change.

Abstract: A solenoid valve includes a solenoid coil to produce a magnetic field when energized, a yoke of magnetic material encasing the solenoid coil, an armature of magnetic material surrounded by the yoke, and arranged to move in an axial direction of the solenoid coil when the solenoid coil is energized, a plunger to be moved with the armature, a valve seat member including a seat portion formed with a valve hole to be closed and opened by a forward end portion of the plunger, and a coil spring which is disposed between a spring receiving portion of the plunger and the valve seat member, around the plunger, and which is arranged to urge the plunger toward a normal position. The plunger includes a pressure receiving portion (such as a flat portion) which extends in a radial direction of the plunger at a position between the forward end portion and the spring receiving portion of the plunger, and which faces to the seat portion.

Abstract: In a gear pump equipped with a pump assembly formed from a driving gear supported by a driving shaft, a driven gear supported by a driven shaft, a pair of side plates disposed at both sides in an axial direction of driving and driven shafts, and a seal block that seals tips of the gears and forms a first fluid chamber by installation onto the side plates, and a casing that houses the pump assembly and forms a second fluid chamber therein, ribs are provided for at least one member of the side plates or the seal block, and fluid tightness between the first and second fluid chambers is secured by exerting pressure between the side plates and seal block and additionally plastically deforming the ribs. By this, it is possible to provide the gear pump which is capable of achieving improvement of the seal integrity while reducing the parts count.

Abstract: A seal apparatus includes at least one pair of gears; a side plate arranged adjacent to the pair of gears; and a housing sandwiching the side plate. At least one of the side plate and the housing includes a shoulder portion. The seal apparatus further includes a seal member arranged between the housing and the side plate and arranged at the shoulder portion. The seal member separates a low pressure area from a high pressure area in a radial direction of the gear. The shoulder portion is located in the low pressure area. At least a part of the seal member faces the high pressure area. The seal apparatus further includes a backup member reinforcing the seal member and facing a tip portion of the shoulder portion; and a containing portion formed between a root portion of the shoulder portion and the seal member to be capable of containing a part of the seal member at least when the seal member is elastically deformed.

Abstract: An apparatus comprising a tandem pump which includes first and second pump sections driven by a rotation shaft, and a housing defining a pump receiving portion including a first pump chamber receiving the first pump section and a second pump chamber receiving the second pump section. The first and second pump chambers are separated by a partition. The partition is positioned by the housing at least in the axial direction of the rotation shaft.

Abstract: In a brake control apparatus, a fluid passage section is hydraulically connected between a hydraulic pressure source and a wheel cylinder. A first pressure sensor measures a first quantity correlated to a hydraulic pressure outputted by the hydraulic pressure source. A second pressure sensor measures a second quantity correlated to an internal pressure of the wheel cylinder. A controller controls a braking force of a wheel by the wheel cylinder. The controller is configured to: allow the first pressure sensor to obtain a value of the first quantity, and allow the second pressure sensor to obtain a value of the second quantity, while allowing a selector to regulate fluid communication between the hydraulic pressure source and the wheel cylinder; and calibrate the first and second pressure sensors with respect to each other in accordance with the obtained values of the first and second quantities.

Abstract: A brake control apparatus including a reservoir tank, a housing, a pump within the housing, a suction port formed in the housing and communicated with a suction portion of the pump, a discharge port formed in the housing and communicating a discharge portion of the pump with wheel cylinders, a suction pipe connecting the suction port and the reservoir tank, and a reservoir chamber disposed within the housing between the suction portion of the pump and the suction port. The reservoir chamber has a volume capable of reserving at least a predetermined amount of the brake fluid which is required for one-time braking at a maximum fluid pressure.

Abstract: In a brake control apparatus with wheel-brake cylinders mounted on respective road wheels, a pump is provided to supply a fluid pressure to each of the wheel-brake cylinders by normal rotation of the pump. A control unit is provided to control rotational motion of the pump to bring an actual wheel-cylinder pressure of each of the wheel-brake cylinders closer to a target wheel-cylinder pressure. Also provided is a pump reverse-rotation suppression device that suppresses reverse rotation of the pump, only when the reverse rotation of the pump is detected.

Abstract: In a gear pump equipped with a pump assembly formed from a driving gear supported by a driving shaft, a driven gear supported by a driven shaft, a pair of side plates disposed at both sides in an axial direction of driving and driven shafts, and a seal block that seals tips of the gears and forms a first fluid chamber by installation onto the side plates, and a casing that houses the pump assembly and forms a second fluid chamber therein, ribs are provided for at least one member of the side plates or the seal block, and fluid tightness between the first and second fluid chambers is secured by exerting pressure between the side plates and seal block and additionally plastically deforming the ribs. By this, it is possible to provide the gear pump which is capable of achieving improvement of the seal integrity while reducing the parts count.

Abstract: A solenoid-valve controller provided with a solenoid valve C which is switchable between the full closed state where a plunger a abuts on a sheet face b and the full open state where the plunger separates from the sheet face, and control means e for carrying out energization to a coil d for driving the plunger a of the solenoid valve C by pulse width modulation control, configured such that there are arranged regenerative-current formation means e for forming a regenerative current in parallel with the coil d, and the control means e are arranged with regenerative-current detection means g for detecting the regenerative current, and the control means e carry out pulse width modulation control based on a detection value of the regenerative-current detection means g. This allows detection of the plunger position during actuation of the solenoid valve by a low-cost and small-sized technique requiring no enhancement of an attraction force of the coil of the solenoid valve.

Abstract: A power steering system includes a fluid pump, a steering gear, a high-pressure passage connecting the fluid pump to the steering gear, and a flow control valve having a first chamber forming a part of the high-pressure passage. A metering orifice is disposed in the high-pressure passage between the first chamber and the steering gear. A feedback passage distributes feedback pressure developed in the high-pressure passage downstream of the metering orifice to a second chamber of the flow control valve. An exhaust port communicates with the first chamber. A movable valve spool is disposed in a valve bore and has one end exposed to the first chamber and opposite end exposed to the second chamber. A valve spring is disposed in the second chamber together with a slide coupled with an external actuator. One end of the valve spring is seated on the opposite end of the valve spool and opposite end thereof is seated on the slide.

Abstract: A steering power assist apparatus is comprised of a power cylinder whose operation is controlled by the a flow rate control valve, a first control valve and a second control valve. The flow rate control valve is connected to a discharge side of a hydraulic pump and controls the amount of the hydraulic oil to be supplied to the first and second control valves according to a load pressure. The first control valve constituted by choke valves is disposed downstream of the flow rate control valve and controls the amount of the hydraulic oil supplied to the second control valve according to a steering torque. The second control valve constituted by choke valves is disposed downstream of the flow rate control valve and controls the amount of the hydraulic oil to the power cylinder according to a steering torque. The choke valves of the second control valve are fully closed after the choke valves of the first control valve are fully closed.

Abstract: A power assisted steering apparatus for a vehicle has a driving source and an actuator for the vehicle's steering mechanism, to power assist the steering operation. The driving source, such as an engine, continuously drives a pump. A working passage is arranged so that working oil discharged from the pump is introduced into the actuator. A check valve is disposed in the working passage, between the actuator and the pump so that the working oil flows only one way to the actuator. An accumulator is connected to the working passage, between the check valve and the actuator to maintain a predetermined pressure in the working passage. A regulator is connected to the working passage, between the pump and the check valve to regulate flow to the actuator. When the pressure within the working passage reaches the predetermined pressure, the working fluid is dumped to a reservoir, bypassing the check valve, the accumulator, and the actuator.

Abstract: A power steering device includes a hydraulic pump for discharging working fluid, an actuator for producing a steering assisting force by means of working fluid, a hydraulic passage for connecting the hydraulic pump and the actuator, a check valve arranged to the hydraulic passage to allow flow of working fluid from the hydraulic pump to the actuator and preventing flow thereof in the opposite direction, an accumulator connected to the hydraulic passage downstream of the check valve, a pressure switch for detecting a pressure within the hydraulic passage downstream of the check valve, a control unit for controlling the hydraulic pump in response to the pressure switch, and a display for showing an anomaly of the power steering device. When determining the anomaly of the power steering device, the control unit stops the hydraulic pump and/or makes the display show the anomaly.

Abstract: A power assisted steering apparatus for a vehicle having a driving source, such as an engine, has an actuator, a hydraulic pump, a working oil pressure passage, and a drive switch. The actuator, which is in the vehicle steering mechanism, receives a supply or exhaust of a working oil to assist the steering operation. The pump is selectively driven by an engine via a clutch mechanism. The working oil discharged from the pump is introduced into the actuator via the passage. The check valve is interposed within the passage to enable flow in one direction away from the pump. The drive switch structure is disposed within the passage, downstream from the check valve. With this arrangement, the drive switch structure can be activated by pressure in the passage downstream of the check valve to control the clutch mechanism.

Abstract: In a power steering system which has a fluid pump and a hydraulic actuator, there is used a flow control device which comprises a spool unit slidably received in a spool receiving bore in a manner to partition the bore into first and second pressure chambers. The spool unit comprises a hollow cylindrical outer spool slidably received in the spool receiving bore. The outer spool has a bottom portion exposed to the second pressure chamber. The bottom portion has an aperture formed therethrough. A cylindrical inner spool is incorporated with the outer spool. The inner spool includes a larger diameter portion slidably received in a major part of the outer spool and a smaller diameter portion slidably received in the aperture of the bottom portion of the outer spool. The inner spool is engaged with a control spring to be biased toward the first pressure chamber. A spring member is employed for biasing the outer and inner spools toward the second and first pressure chambers respectively.