Abstract: A variable displacement pump according to the present invention is notably configured such that the opening area of a variable metering orifice (MO) is variably controlled by a second control valve (6) as a spool valve having a second spool valve body (61). According to this type of the second control valve (6), a larger amount of movement (stroke movement) of the second spool valve body (61) can be ensured. Consequently, the opening area of the variable metering orifice (MO) can be controlled without being restricted by a range of variation in a proper discharge amount based on an amount of movement of a cam ring (2), thereby achieving sufficient energy conservation of the pump.

Abstract: A variable displacement pump according to the present invention is notably configured such that the opening area of a variable metering orifice (MO) is variably controlled by a second control valve (6) as a spool valve having a second spool valve body (61). According to this type of the second control valve (6), a larger amount of movement (stroke movement) of the second spool valve body (61) can be ensured. Consequently, the opening area of the variable metering orifice (MO) can be controlled without being restricted by a range of variation in a proper discharge amount based on an amount of movement of a cam ring (2), thereby achieving sufficient energy conservation of the pump.

Abstract: A pump device is configured so that a first drive shaft 20 for driving a first pump element E1 and a second drive shaft 40 for driving a second pump element E2 are connected through a third drive shaft 50, and a first joint 51 and a second joint 52 are respectively connected between the first drive shaft 20 and the third drive shaft 50, and between the second drive shaft 40 and the third drive shaft 50, each of the first joint and the second joint being configured to permit a joining angle change or a change in an amount of eccentricity between the corresponding drive shafts. As a result of this configuration, a flexural deformation produced in the first and second drive shafts 20, 40 can be absorbed by means of the first and second joints 51, 52, and thus it is possible to suppress the problem of the flexural deformation of one of the first and second drive shafts 20, 40 affecting the other.

Abstract: A variable displacement vane pump, including a pump body, a driving shaft, a rotor, a cam ring swingable on a swing support surface, first and second plate members on opposite sides of the cam ring, a suction port and a discharge port on a side of at least one of the first and second plate members, a seal cooperating with the swing support surface to divide a space on an outer circumferential side of the cam ring into first and second fluid pressure chambers, a fluid pressure control valve, a stop disposed on the pump body on a side of the first fluid pressure chamber and restricting a swing movement of the cam ring, and a detent disposed between the cam ring and the pump body on a side of the second fluid pressure chamber and preventing a rotational movement of the cam ring around the driving shaft.

Abstract: A variable displacement pump includes a control valve formed with a high-pressure chamber for introducing therein high-pressure fluid on the upstream side of a metering orifice, a pressure chamber for introducing therein pressure fluid on the downstream side of the metering orifice, a low-pressure chamber arranged between the high-pressure and pressure chambers for introducing therein low-pressure fluid, and a communication passage for providing fluid communication between one of the high-pressure and low-pressure chambers and a first fluid-pressure chamber of the pump.

Abstract: A variable displacement pump includes a rear cover and side plate arranged on both sides of a cam ring and making slide contact with the cam ring. The rear cover has an end face on the side of the cam ring, which is formed with a suction port. A seal member is arranged in a chamber formed between a pump housing and the cam ring and for dividing the chamber into two portions that define first and second working chambers. A connection groove and terminal groove are formed in the end face of the rear cover to provide fluid communication between the suction port and the second working chamber.

Abstract: A variable displacement pump includes a rear cover and side plate arranged on both sides of a cam ring and making slide contact with the cam ring. The rear cover has an end face on the side of the cam ring, which is formed with a suction port. A seal member is arranged in a chamber formed between a pump housing and the cam ring and for dividing the chamber into two portions that define first and second working chambers. A connection groove and terminal groove are formed in the end face of the rear cover to provide fluid communication between the suction port and the second working chamber.

Abstract: A variable displacement pump includes a control valve formed with a high-pressure chamber for introducing therein high-pressure fluid on the upstream side of a metering orifice, a pressure chamber for introducing therein pressure fluid on the downstream side of the metering orifice, a low-pressure chamber arranged between the high-pressure and pressure chambers for introducing therein low-pressure fluid, and a communication passage for providing fluid communication between one of the high-pressure and low-pressure chambers and a first fluid-pressure chamber of the pump.

Abstract: A cam case 23 is provided which swingably supports a cam ring 34 fitted to a rotor 33 having a vane 33a to form a pump chamber 36 from the outer surface such that the cam ring 34 is swingably supported by 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 low-pressure chamber 80 for introducing low-level hydraulic pressure is formed at a position between the backside of the pressure plate and the front body, the position opposing a suction-side region 36A of the pump chamber.

Abstract: A variable displacement pump includes pump bodies, a cam ring, first and second fluid pressure chambers, a rotor, a driving shaft, a pump chamber, a compression coil spring, a metering restrictor portion, and a control valve. A plunger damper is formed to incorporate the compression coil spring such that a distal end of the plunger damper abuts against a side portion of the cam ring in the second fluid pressure chamber. A small hole constituting the metering restrictor portion is formed at such a position that it is opened/closed by a slidable motion of the plunger damper during a swing motion of the cam ring, and such that it is partitioned from the second fluid pressure chamber, so that an opening area of the small hole changes in an interlocking manner to the swing motion of the cam ring.

Abstract: A variable displacement pump has a swingable, displaceable cam ring fitted to form a pump chamber together with the outer circumferential surface of a rotor having vanes. Notches are formed by notching to have a substantially V-letter shape in the starting end portions, in the rotating direction of the rotor, of a pump suction opening and pump discharge opening that open to the pump chamber. The notch formed in the starting end portion, in the rotor rotating direction, of the pump suction opening is constituted by a plurality of notched grooves aligned in the radial direction of the pump chamber and having different lengths in the rotating direction of the rotor. Hence, the timing at which the pump suction opening communicates with a pressure chamber formed between the vanes changes in accordance with swing and displacement of the cam ring.

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: A variable capacity pump includes a rotor, a plurality of vanes, a cam ring, a spring, a variable orifice, first and second fluid pressure chambers, and first and second openings. The spring biases the cam ring to a position where a volume of the pump chamber of a portion ranging from a pump suction region to a pump discharge region becomes maximum. The variable metering orifice is formed midway along a discharge passage of a pressure fluid discharged from the pump chamber. The first and second fluid pressure chambers are formed between the outer circumferential portion of the cam ring and the inner circumferential surface of the pump body to be divided in a biasing direction of the cam ring, and swing the cam ring upon introduction of input and output fluid pressures of the metering orifice thereto. The first and second openings respectively open to the pump suction region and the pump discharge region of the pump chamber to have opening areas that are changed by a swing of the cam ring.

Abstract: In a rotary pump with a pressure switch, a pressure switch mounting space constituted by a small- and large-diameter holes is formed to be parallel to a rotating shaft in an end face portion of a front body to which a rear body is not joined. A pump outlet side fluid pressure is introduced to an inner end of the small-diameter hole. The large-diameter hole is connected to a pump inlet side. A plunger is slidably arranged in the small-diameter hole. The plunger is normally biased toward the inner end of the small-diameter hole and is kept movable toward the large-diameter hole depending on a magnitude of the fluid pressure of the pump outlet side. A pressure detector is operated when the fluid pressure of the pump outlet side exceeds a predetermined value.