Abstract: A variable displacement vane pump includes a first and a second fluid pressure chamber (31,32) where the cam ring (4) is made eccentric to the rotor (2) by a pressure difference between the first and the second fluid pressure chamber (31,32), a control valve (21) for controlling a pressure of the first and the second fluid pressure chamber (31,32) so that an eccentric amount of the cam ring (4) is reduced to be small with an increase in a rotation speed of the rotor (2), and a flow amount limiting member (22e) for limiting a discharge flow amount of the operating fluid in the second fluid pressure chamber (32) at the time the eccentric amount of the cam ring (4) to the rotor (2) becomes small by supplying the operating fluid to the first fluid pressure chamber (31) and by discharging the operating fluid from the second fluid pressure chamber (32).

Abstract: A solenoid actuator (1) comprises a case (9) made of a magnetic material and housing a coil (12) wound on a bobbin (11), and a pressure tube (17) made of a non-magnetic material and fitted into a hollow portion of the bobbin (11). A base (2) and a sleeve (3) made of a magnetic material are disposed in the pressure tube (17). A plunger (4) provided in an operation chamber (74, 75) formed in the base (2) and the sleeve (3) strokes according to energization of the coil (12) to axially drive a shaft (5) fixed to the plunger (4). The pressure tube (17) ensures that magnetic flux is transferred between the case (9) and the sleeve (3) while preventing pressure variation in the operation chamber (74, 75) from being transmitted to the bobbin (11), thereby achieving a high response and a pressure tightness in the solenoid actuator (1).

Abstract: A solenoid actuator (1) attached to a hydraulic equipment comprises a shaft (5) connected to the hydraulic equipment, a plunger (4) fixed to the shaft (5), a coil (12) which magnetically drives the plunger (4), and a first bearing (7) and a second bearing (8) supporting the shaft (5) on both sides of the plunger (4). A plunger front chamber (74) is formed between the first bearing (7) and the plunger (4), a plunger rear chamber (75) is formed between the plunger (4) and the second bearing (8), and a second bearing rear chamber (76) is formed on the opposite side of the second bearing (8) to the plunger rear chamber (75). To secure an oil flow between these chambers, a plunger exterior oil passage (63), a second bearing oil passage (64), and a shaft-penetrating oil passage (65) are provided, thereby realizing a preferable balance between oil pressures acting on the second bearing (8).

Abstract: A solenoid actuator (1) comprises a case (9) made of a magnetic material and housing a coil (12) wound on a bobbin (11), and a pressure tube (17) made of a non-magnetic material and fitted into a hollow portion of the bobbin (11). A base (2) and a sleeve (3) made of a magnetic material are disposed in the pressure tube (17). A plunger (4) provided in an operation chamber (74, 75) formed in the base (2) and the sleeve (3) strokes according to energization of the coil (12) to axially drive a shaft (5) fixed to the plunger (4). The pressure tube (17) ensures that magnetic flux is transferred between the case (9) and the sleeve (3) while preventing pressure variation in the operation chamber (74, 75) from being transmitted to the bobbin (11), thereby achieving a high response and a pressure tightness in the solenoid actuator (1).

Abstract: A solenoid actuator (1) attached to a hydraulic equipment comprises a shaft (5) connected to the hydraulic equipment, a plunger (4) fixed to the shaft (5), a coil (12) which magnetically drives the plunger (4), and a first bearing (7) and a second bearing (8) supporting the shaft (5) on both sides of the plunger (4). A plunger front chamber (74) is formed between the first bearing (7) and the plunger (4), a plunger rear chamber (75) is formed between the plunger (4) and the second bearing (8), and a second bearing rear chamber (76) is formed on the opposite side of the second bearing (8) to the plunger rear chamber (75). To secure an oil flow between these chambers, a plunger exterior oil passage (63), a second bearing oil passage (64), and a shaft-penetrating oil passage (65) are provided, thereby realizing a preferable balance between oil pressures acting on the second bearing (8).

Abstract: A solenoid actuator (1) attached to hydraulic equipment comprises a shaft (5) connected to the hydraulic equipment, a plunger (4) fixed to the shaft (5), a coil (12) which magnetically drives the plunger (4), and a first bearing (7) and a second bearing (8) supporting the shaft (5) on either sides of the plunger (4). A plunger front chamber (74) is formed between the first bearing (7) and the plunger (4), and a plunger rear chamber (75) is formed between the plunger (4) and the second bearing (8). By providing a plunger exterior oil passage (63) on the outside of the plunger (4) to connect the plunger front chamber (74) to the plunger rear chamber (75), working oil flows through the plunger exterior oil passage (63) every time the plunger (4) strokes, thereby preventing a deposit of contaminant on the plunger (4) without increasing a stroke resistance of the plunger (4).

Abstract: A variable capacity vane pump (100) has a pump housing (10) having a high-load bearing part (10a) on which a higher load is exerted than another part when the pump vane pump (100) operates. A control valve (21) for varying a capacity of the vane pump (100) is provided in a valve housing (28) which is formed integrally in the pump housing (10). By arranging the valve housing (28) on the same side of the pump housing (10) as the high-load bearing part (10a) with respect to the rotation axis of the vane pump (100), the high-load bearing part (10a) can be reinforced without increasing the size of the vane pump (100).

Abstract: A variable displacement vane pump includes a first and a second fluid pressure chamber (31,32) where the cam ring (4) is made eccentric to the rotor (2) by a pressure difference between the first and the second fluid pressure chamber (31,32), a control valve (21) for controlling a pressure of the first and the second fluid pressure chamber (31,32) so that an eccentric amount of the cam ring (4) is reduced to be small with an increase in a rotation speed of the rotor (2), and a flow amount limiting member (22e) for limiting a discharge flow amount of the operating fluid in the second fluid pressure chamber (32) at the time the eccentric amount of the cam ring (4) to the rotor (2) becomes small by supplying the operating fluid to the first fluid pressure chamber (31) and by discharging the operating fluid from the second fluid pressure chamber (32).

Abstract: A variable displacement vane pump includes a first and a second fluid pressure chamber (31,32) where the cam ring (4) is made eccentric to the rotor (2) by a pressure difference between the first and the second fluid pressure chamber (31,32), a control valve (21) for controlling a pressure of the first and the second fluid pressure chamber (31,32) so that an eccentric amount of the cam ring (4) is reduced to be small with an increase in a rotation speed of the rotor (2), a pressure applying section (36) for applying a pressure to the cam ring (4) in a direction of increasing the eccentric amount all the time, and a cam ring movement restricting portion (12) for defining a minimum eccentric amount of the cam ring (4) by restricting the movement of the cam ring (4) in a direction of decreasing the eccentric amount.