There is disclosed a pump apparatus which can more accurately determine the occurrence of an abnormal vibration. The pump apparatus includes: a pump; an electric motor for driving the pump; an inverter as a speed changing means for the electric motor; a vibration detector for detecting at least one of a vibration of the pump, a vibration of the electric motor and a vibration of the inverter; and a controller for controlling the pump. The controller includes a storage unit for storing a measured vibration value measured by the vibration detector. The storage unit has a storage table which, when the rotational speed of the pump is increased stepwise to a predetermined rotational speed, stores the measured vibration value measured at each step.

A hydraulic gerotor pump for an automatic transmission may comprise a housing and a gear set rotatably disposed within the housing. The gear set may comprise an inner gear and an outer gear having radially opposed intermeshing teeth that together define a plurality of circumferentially disposed variable volume pumping chambers therebetween. The housing may be made of a first aluminum-based material, and the inner gear and the outer gear of the gear set may be made of a second aluminum-based material. The linear coefficient of thermal expansion of the first aluminum-based material may be substantially the same as that of the second aluminum-based material.

A hydraulic gerotor pump for an automatic transmission may comprise a housing and a gear set rotatably disposed within the housing. The gear set may comprise an inner gear and an outer gear having radially opposed intermeshing teeth that together define a plurality of circumferentially disposed variable volume pumping chambers therebetween. The housing may be made of a first aluminum-based material, and the inner gear and the outer gear of the gear set may be made of a second aluminum-based material. The linear coefficient of thermal expansion of the first aluminum-based material may be substantially the same as that of the second aluminum-based material.

A variable displacement pump device includes a pump, a mover, a biasing member, first and second control chambers, and a controller. The first and second control chambers are provided between an inner periphery of a containing chamber of a housing and an outer periphery of the mover. Hydraulic oil is introduced from a discharge port into the first control chamber. The pump is configured to permit oil to be introduced from the discharge port into the second control chamber via a supply/discharge passage or to be discharged from inside the second control chamber. The second control chamber is located adjacent to any of the pump chambers in a discharge region or the discharge port via the mover. The controller is configured to switch states in which the second control chamber is opened and closed to the supply/discharge passage.

A variable displacement pump device includes a pump, a mover, a biasing member, first and second control chambers, and a controller. The first and second control chambers are provided between an inner periphery of a containing chamber of a housing and an outer periphery of the mover. Hydraulic oil is introduced from a discharge port into the first control chamber. The pump is configured to permit oil to be introduced from the discharge port into the second control chamber via a supply/discharge passage or to be discharged from inside the second control chamber. The second control chamber is located adjacent to any of the pump chambers in a discharge region or the discharge port via the mover. The controller is configured to switch states in which the second control chamber is opened and closed to the supply/discharge passage.

A vacuum pressure proportional control valve placed on a pipe connecting between a reaction vessel and a vacuum pump to control the vacuum pressure in the reaction vessel includes a cylinder provided with a piston chamber, a piston housed in the piston chamber so as to make reciprocal linear movement, a valve seat surface, and a valve element which contacts with or separates from the valve seat surface according to the movement of the piston. A stopper member is provided in the cylinder so that a leading end portion of the stopper member is placed in the piston chamber. The stopper member is configured to move the piston back and forth in a moving direction of the piston by use of an adjusting unit to thereby adjust the position of the leading end portion.

The invention relates to a continuously variable transmission and a transmission system comprising said continuously variable transmission, wherein the continuously variable transmission comprises a first gear pump and a second gear pump, wherein each gear pump comprises a first gear and a second gear meshing with the first gear over an overlap distance in an overlap direction parallel to the first gear axis, wherein each gear pump further comprises an adjustment member for adjusting the pump volume, wherein the adjustment member of the first gear pump and the adjustment member of the second gear pump are interconnected by a connecting member for adjusting the pump volume of the first gear pump and the pump volume of the second gear pump in an inverse correlation to each other.

A pump apparatus which can more accurately determine the occurrence of an abnormal vibration. The pump apparatus includes: a pump; an electric motor for driving the pump; an inverter as a speed changing means for the electric motor; a vibration detector for detecting at least one of a vibration of the pump, a vibration of the electric motor and a vibration of the inverter; and a controller for controlling the pump. The controller includes a storage unit for storing a measured vibration value measured by the vibration detector. The storage unit has a storage table which, when the rotational speed of the pump is increased stepwise to a predetermined rotational speed, stores the measured vibration value measured at each step.

A fluid transfer pump that has a housing, a body portion movable within the housing between a first position and a second position, a gear coupled to the housing, a body cavity defined partially between the body portion and the housing, and an aperture defined in the housing that selectively provides a fluid to the body cavity. When the fluid is applied to the body cavity at or above a pilot pressure, the body portion is in the first position adjacent to the gear and when the fluid is applied to the body cavity at a fluid pressure lower than the pilot pressure, the body portion is in the second position and spaced from the gear.

A fluid transfer pump that has a housing, a body portion movable within the housing between a first position and a second position, a gear coupled to the housing, a body cavity defined partially between the body portion and the housing, and an aperture defined in the housing that selectively provides a fluid to the body cavity. When the fluid is applied to the body cavity at or above a pilot pressure, the body portion is in the first position adjacent to the gear and when the fluid is applied to the body cavity at a fluid pressure lower than the pilot pressure, the body portion is in the second position and spaced from the gear.