Pump control arrangement for automatic automotive transmission or the like
In a transmission, having a torque converter a hydraulic control circuit is described for controlling the transmission comprising: a variable capacity pump for supplying fluid under pressure, the pump having a control arrangement including a control chamber, the control arrangement varying the capacity of the pump in response to the pressure prevailing in the control chamber; a pressure regulator valve for regulating the output of the pump by draining off some of the fluid discharged by the pump and developing a control pressure, the pressure regulating pump having first and second drain ports, the first drain port fluidly communicating with the torque converter through a first conduit, the second drain port fluidly communicating with the control chamber through a second conduit; and a pressure limiting valve disposed in the first conduit for limiting the pressure fed to the torque converter through the first conduit, the pressure limiting valve having a feedback chamber which is supplied with the pressure prevailing in the first conduit downstream of the pressure limiting valve, the above arrangement being such as to maintain the pressure in the control chamber at a which minimizes the power consumption of the pump with respect to the level of control pressure produced by the regulator valve wherein the pressure limiting valve comprises: a spool reciprocatively disposed in a bore, the bore including a variable volume feedback chamber defined therein by the spool, an inlet port which communicates with the first drain port, an outlet port which communicates with the torque converter, a drain port and a feedback port which is in fluid communication with the feedback chamber and the outlet port via a flow restriction, the spool being arranged to control the communication between the inlet and drain ports so as to control the pressure prevailing at the outlet port in response to the pressure prevailing in the feedback chamber.
- Assignee:
- Nissan Motor Co., Ltd., Yokohama
- Patent Number(s):
- US 4598612
- OSTI ID:
- 5393494
- Resource Relation:
- Patent File Date: Filed date 21 Mar 1984
- Country of Publication:
- United States
- Language:
- English
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