US3714869A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic power brake unit
Assignee: Motors Liquidation Co
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Filing: 1971-03-26
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Granted: 1973-02-06
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Expires: 1991-03-26
Abstract
Abstract A hydraulic power brake unit including a power piston operatively engaging a conventional master cylinder and an annular valve spool having differential end areas communicating with the power chamber formed by the power piston and being normally positioned in the housing to communicate hydraulic fluid from a pressure source to the power steering unit and communicate the power chamber to the power source reservoir. When the brake pedal is actuated, an actuating spring acting between the valve spool and a reaction piston attached to the pedal pushrod is compressed and the valve spool is moved to restrict fluid communication from the pressure source to the power steering unit and divert the flow to the power chamber while simultaneously blocking communication of the power chamber to the reservoir so that the power chamber is pressurized and the power piston fluidly displaced to actuate the master cylinder. The power chamber pressure acts on the differential area of the valve spool to resist its movement by the actuating spring and causes it to function as a regulating valve which continuously provides a power chamber pressure proportional to the force of the actuating spring. Upon a malfunction caused loss of hydraulic pressure the reaction piston moves into abutting engagement with the power piston to provide a rigid force transmitting link between the pushrod and the master cylinder whereby the brakes are actuated independently of the hydraulic boost.
Inventors
- 👤 D Flory
- 👤 E Moyer
- 👤 T Naismith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:49
CPC Classifications
B; B60; B60T; B60T13/00; B60T13/10; B60T13/12; B60T13/16; B60T13/161; B60T13/162; B60T13/163
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
279 words
A hydraulic brake booster comprising: a housing having a longitudinally extending stepped bore therein, a pressure inlet port, a reservoir port, and a power steering port; a power piston sealingly slidable in the stepped bore to define a power chamber; a valve spool slidable in the stepped bore and having at least first and second axially spaced lands forming a first annular chamber therebetween and with the stepped bore, said first land having an undercut portion forming a second annular chamber with the stepped bore and communicating with the first annular chamber, and fluid passage means in the spool communicating with the power chamber, said lands being located in relation to the aforementioned ports and fluid passage means whereby the first and second annular chambers communicate fluid from the pressure inlet port to the power steering port and the power chamber communicates with the reservoir port; operator actuatable means including spring means engaging the valve spool and urging it to move relative to the housing to an operating position wherein the first and second annular chambers restrictively communicate the pressure inlet port to the power steering port and the resulting increased inlet port pressure is communicated to the power chamber through the passage means to actuate the power piston; and the valve spool having a stepped outer diameter cooperable with the stepped housing bore to provide a differential end area acted upon by the power chamber pressure in a direction opposing the operator actuatable means whereby the spool is balanced by the opposing forces in a poised position wherein the first and second lands respectively block communication between the power chamber and both the pressure inlet and reservoir ports.
Claim 2
Dependent Claim
279 words
A hydraulic brake booster comprising: a housing having a longitudinally extending stepped bore therein, a pressure inlet port, a reservoir port, and a power steering port; a power piston sealingly slidable in the stepped bore to define a power chamber; a valve spool slidable in the stepped bore and having at least first and second axially spaced lands forming a first annular chamber therebetween and with the stepped bore, said first land having an undercut portion forming a second annular chamber with the stepped bore and communicating with the first annular chamber, and fluid passage means in the spool communicating with the power chamber, said lands being located in relation to the aforementioned ports and fluid passage means whereby the first and second annular chambers communicate fluid from the pressure inlet port to the power steering port and the power chamber communicates with the reservoir port; operator actuatable means including spring means engaging the valve spool and urging it to move relative to the housing to an operating position wherein the first and second annular chambers restrictively communicate the pressure inlet port to the power steering port and the resulting increased inlet port pressure is communicated to the power chamber through the passage means to actuate the power piston; and the valve spool having a stepped outer diameter cooperable with the stepped housing bore to provide a differential end area acted upon by the power chamber pressure in a direction opposing the operator actuatable means whereby the spool is balanced by the opposing forces in a poised position wherein the first and second lands respectively block communication between the power chamber and both the pressure inlet and reservoir ports.
Claim 3
Dependent Claim
279 words
A hydraulic brake booster comprising: a housing having a longitudinally extending stepped bore therein, a pressure inlet port, a reservoir port, and a power steering port; a power piston sealingly slidable in the stepped bore to define a power chamber; a valve spool slidable in the stepped bore and having at least first and second axially spaced lands forming a first annular chamber therebetween and with the stepped bore, said first land having an undercut portion forming a second annular chamber with the stepped bore and communicating with the first annular chamber, and fluid passage means in the spool communicating with the power chamber, said lands being located in relation to the aforementioned ports and fluid passage means whereby the first and second annular chambers communicate fluid from the pressure inlet port to the power steering port and the power chamber communicates with the reservoir port; operator actuatable means including spring means engaging the valve spool and urging it to move relative to the housing to an operating position wherein the first and second annular chambers restrictively communicate the pressure inlet port to the power steering port and the resulting increased inlet port pressure is communicated to the power chamber through the passage means to actuate the power piston; and the valve spool having a stepped outer diameter cooperable with the stepped housing bore to provide a differential end area acted upon by the power chamber pressure in a direction opposing the operator actuatable means whereby the spool is balanced by the opposing forces in a poised position wherein the first and second lands respectively block communication between the power chamber and both the pressure inlet and reservoir ports.
Claim 4
Dependent Claim
279 words
A hydraulic brake booster comprising: a housing having a longitudinally extending stepped bore therein, a pressure inlet port, a reservoir port, and a power steering port; a power piston sealingly slidable in the stepped bore to define a power chamber; a valve spool slidable in the stepped bore and having at least first and second axially spaced lands forming a first annular chamber therebetween and with the stepped bore, said first land having an undercut portion forming a second annular chamber with the stepped bore and communicating with the first annular chamber, and fluid passage means in the spool communicating with the power chamber, said lands being located in relation to the aforementioned ports and fluid passage means whereby the first and second annular chambers communicate fluid from the pressure inlet port to the power steering port and the power chamber communicates with the reservoir port; operator actuatable means including spring means engaging the valve spool and urging it to move relative to the housing to an operating position wherein the first and second annular chambers restrictively communicate the pressure inlet port to the power steering port and the resulting increased inlet port pressure is communicated to the power chamber through the passage means to actuate the power piston; and the valve spool having a stepped outer diameter cooperable with the stepped housing bore to provide a differential end area acted upon by the power chamber pressure in a direction opposing the operator actuatable means whereby the spool is balanced by the opposing forces in a poised position wherein the first and second lands respectively block communication between the power chamber and both the pressure inlet and reservoir ports.
Claim 5
Dependent Claim
360 words
A hydraulic brake booster comprising: a housing having a longitudinally extending stepped bore therethrough, a pressure inlet port, a reservoir port, and a power steering port; a power piston sealingly slidable in the stepped bore to define a power chamber; a valve spool slidable in the stepped bore and having a stepped outer diameter forming a shoulder cooperable with the stepped housing bore to limit movement of the valve spool in one direction and to provide a differential end area on the spool, at least first and second axially spaced lands forming a first annular chamber therebetween, said first land having an undercut portion forming with the stepped bore a second annular chamber communicating with the first annular chamber, and fluid passage means in the spool communicating the axially outer ends of the first and second lands to the power chamber; first spring means urging the valve spool to a position relative to the housing wherein the shoulder engages the stepped bore and wherein the power chamber is communicated to the reservoir port and the first and second annular chambers unrestrictingly communicate fluid from the pressure inlet port to the power steering port; operator actuatable means including a reaction piston sealingly slidable in the stepped bore and forming a wall of the power chamber to provide a reaction force on the operator actuatable means proportional to the power chamber pressure; second spring means acting between the reaction piston and the valve spool and upon operator actuation urging the valve spool to an operating position relative the housing wherein the first and second annular chambers restrictively communicate the fluid inlet port to the power steering port and the resulting inlet port pressure increase is communicated to the power chamber through the fluid passage means to actuate the power piston and the master cylinder; and the power chamber pressure acting on the differential end area of the valve spool causes the spool to continuously seek a balanced position wherein the first and second lands block communication between the power chamber and both the pressure inlet and reservoir ports so that the power chamber pressure is regulated proportionally to the second spring force.
Claim 6
Dependent Claim
360 words
A hydraulic brake booster comprising: a housing having a longitudinally extending stepped bore therethrough, a pressure inlet port, a reservoir port, and a power steering port; a power piston sealingly slidable in the stepped bore to define a power chamber; a valve spool slidable in the stepped bore and having a stepped outer diameter forming a shoulder cooperable with the stepped housing bore to limit movement of the valve spool in one direction and to provide a differential end area on the spool, at least first and second axially spaced lands forming a first annular chamber therebetween, said first land having an undercut portion forming with the stepped bore a second annular chamber communicating with the first annular chamber, and fluid passage means in the spool communicating the axially outer ends of the first and second lands to the power chamber; first spring means urging the valve spool to a position relative to the housing wherein the shoulder engages the stepped bore and wherein the power chamber is communicated to the reservoir port and the first and second annular chambers unrestrictingly communicate fluid from the pressure inlet port to the power steering port; operator actuatable means including a reaction piston sealingly slidable in the stepped bore and forming a wall of the power chamber to provide a reaction force on the operator actuatable means proportional to the power chamber pressure; second spring means acting between the reaction piston and the valve spool and upon operator actuation urging the valve spool to an operating position relative the housing wherein the first and second annular chambers restrictively communicate the fluid inlet port to the power steering port and the resulting inlet port pressure increase is communicated to the power chamber through the fluid passage means to actuate the power piston and the master cylinder; and the power chamber pressure acting on the differential end area of the valve spool causes the spool to continuously seek a balanced position wherein the first and second lands block communication between the power chamber and both the pressure inlet and reservoir ports so that the power chamber pressure is regulated proportionally to the second spring force.
References Cited (Backward Citations)
US3173339A
Cited
US3532027A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |