| 摘要 |
A charging valve is disclosed which controls flow of fluid into an accumulator used with a closed center hydraulic brake booster in a vehicle hydraulic system. The charging valve includes a back pressure producing device which creates a fluid pressure level within the charging valve sufficiently high to charge the accumulator while permitting sufficient fluid flow through the charging valve to operate the power steering gear of the vehicle. A shutoff valve is provided in the passage between the inlet of the charging valve and the accumulator. A second valve within the housing maintains the shutoff valve open as long as the fluid pressure level in the accumulator is below a predetermined value, but permits the shutoff valve to close when the fluid pressure level in the accumulator attains the predetermined value. The second valve also operates the back pressure producing device which restricts fluid flow between the inlet and the outlet when the fluid pressure level in the accumulator is below the predetermined value, but permits substantially unrestricted flow between the inlet and outlet of the charging valve when the fluid pressure level in the accumulator attains the predetermined value.
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