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 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).