초록 ▼

A fluid pressure system includes a source of water pressure 12, a first fluid motor 27 actuated by the pressurized water, a variable displacement hydraulic pump 11, and a second fluid motor 14 actuated by hydraulic fluid from the pump. The pump includes a control device 20 having a control chamber f

A fluid pressure system includes a source of water pressure 12, a first fluid motor 27 actuated by the pressurized water, a variable displacement hydraulic pump 11, and a second fluid motor 14 actuated by hydraulic fluid from the pump. The pump includes a control device 20 having a control chamber for changing the displacement of the pump. A proportional valve 17 is hydraulically connected to the control chamber for changing the pressure in the control chamber. The proportional valve includes a housing 34, 35 and a diaphragm 36 dividing the housing into first and second chambers 39 and 41. The first chamber is connected to the first fluid motor, and the second chamber is connected to the pump inlet. The pump control chamber is hydraulically connected to the second chamber through a variable orifice, and the size of the orifice is changed in response to the pressure in the first chamber and first fluid motor. By this arrangement, the variable displacement pump is controlled by the water pressure in the first fluid motor.

대표청구항 ▼

A pump comprising a variable displacement flow generating means, control means for changing the displacement rate of said flow generating means, said control means including a control chamber, a proportional valve hydraulically connected to said control chamber for changing the pressure in said cont

A pump comprising a variable displacement flow generating means, control means for changing the displacement rate of said flow generating means, said control means including a control chamber, a proportional valve hydraulically connected to said control chamber for changing the pressure in said control chamber, said proportional valve including a housing, separator means disposed in said housing and defining first and second chambers, a first fluid in said first chamber and a second fluid in said second chamber, said first fluid being different from said second fluid, means hydraulically connecting said control chamber with said second chamber through a variable orifice, and means to change the size of said orifice in response to the pressure in said first chamber.