Abstract: In a gear pump in which a driving rotor that is driven by a driving source meshes with a driven rotor that is driven by the driving rotor for rotation to pump a hydraulic oil, only one of the driving rotor and the driven rotor is given the steam treatment while the other remains untreated.

Abstract: In a gear pump in which a driving rotor that is driven by a driving source meshes with a driven rotor that is driven by the driving rotor for rotation to pump a hydraulic oil, only one of the driving rotor and the driven rotor is given the steam treatment while the other remains untreated.

Abstract: A stepped down groove 53 is provided around the peripheral surface of a rod portion 43 of a spool 40 which faces a third oil groove 33. Both the axial ends 53a and 53b of the stepped down groove 53 are located axially outside of both the axial ends 33a and 33b of the third oil groove 33 at least while the valve is in pressure-adjusting condition. Also, another stepped down groove 52 is provided around a land 42 which faces a first oil groove 31. Both the axial ends 52a and 52b of the stepped down groove 52 come, respectively, to the right and left sides of the axial end 31b of the first oil groove 31 to which end the spool 40 shifts to increase the opening of the oil groove at least while the valve is in pressure-adjusting condition.

Abstract: A stepped down groove 53 is provided around the peripheral surface of a rod portion 43 of a spool 40 which faces a third oil groove 33. Both the axial ends 53a and 53b of the stepped down groove 53 are located axially outside of both the axial ends 33a and 33b of the third oil groove 33 at least while the valve is in pressure-adjusting condition. Also, another stepped down groove 52 is provided around a land 42 which faces a first oil groove 31. Both the axial ends 52a and 52b of the stepped down groove 52 come, respectively, to the right and left sides of the axial end 31b of the first oil groove 31 to which end the spool 40 shifts to increase the opening of the oil groove at least while the valve is in pressure-adjusting condition.

Abstract: A hydraulic controller comprises a structure composed of a separator plate 70 sandwiched between first and second valve bodies 60a and 80a, in which structure, an oil passage 103 connecting a SC shift valve 92 provided upstream and a SC backup valve 94 provided downstream is provided with a choke 75. When the separator plate 70, in which a choke opening 75a is formed, is sandwiched between the first and second valve bodies, the upstream part of the oil passage 103 is in fluid communication with one end of the choke opening 75a while the downstream part of the oil passage 103 is in fluid communication with the other end of the choke opening 75a. In this arrangement, a long narrow room formed by the choke opening 75a sandwiched between the first and second valve bodies comprises the choke 75.

Abstract: A hydraulic controller comprises a structure composed of a separator plate 70 sandwiched between first and second valve bodies 60a and 80a, in which structure, an oil passage 103 connecting a SC shift valve 92 provided upstream and a SC backup valve 94 provided downstream is provided with a choke 75. When the separator plate 70, in which a choke opening 75a is formed, is sandwiched between the first and second valve bodies, the upstream part of the oil passage 103 is in fluid communication with one end of the choke opening 75a while the downstream part of the oil passage 103 is in fluid communication with the other end of the choke opening 75a. In this arrangement, a long narrow room formed by the choke opening 75a sandwiched between the first and second valve bodies comprises the choke 75.