Patent ID: 8668468

Claim:
A hydraulic pump system for an automatic transmission, comprising: a first hydraulic pump that generates a first hydraulic pressure to supply a low pressure portion with the first hydraulic pressure; a second hydraulic pump that receives the first hydraulic pressure to generate a second hydraulic pressure higher than the first hydraulic pressure, wherein the second hydraulic pump supplies a high pressure portion with the second hydraulic pressure; a drive portion that rotates a drive shaft integrally interconnecting the first hydraulic pump with the second hydraulic pump; wherein the first hydraulic pump is connected to an oil fan through a first suction hole to draw in oil and is connected to the low pressure portion through a first discharge hole to discharge the first hydraulic pressure; and wherein the second hydraulic pump draws the first hydraulic pressure through a connection passage that connects the first discharge hole with a second suction hole and is connected to the high pressure portion through a second discharge hole to discharge the second hydraulic pressure; wherein the first discharge hole is connected to the low pressure portion through a low pressure passage and the second discharge hole is connected to the high pressure portion through a high pressure passage; wherein a first switch valve that is connected to the high pressure passage controls oil that is diverged from the second hydraulic pressure, and wherein a high pressure regulating valve that is connected to the first switch valve controls oil passing the first switch valve that is turned on to set the second hydraulic pressure and recirculates remained oil to the second suction hole.