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US3738708A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brake pressure control valve
Assignee: Toyota Motor Corp
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Filing: 1972-03-13
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Granted: 1973-06-12
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Expires: 1992-03-13
Abstract
Abstract A brake pressure control valve for a vehicle brake system which comprises a cylinder, a differential piston slidably disposed within the cylinder to subdivide the cylinder interior into first and second chambers facing piston surfaces of different areas and connected respectively to a master cylinder and to rear-wheel brake cylinders, a valve cooperable with the piston to control the intercommunication between the two chambers by way of hydraulic pressure differences produced by the piston, and a first spring biasing the piston to keep the valve normally open. The brake pressure control valve further comprises an assistant plunger slidably engaged within the piston to subdivide the piston interior into third and fourth chambers, the third chamber being in open communication with the first chamber and the fourth chamber being connected to the second chamber, and a second spring normally biasing the plunger in a direction to axially unite the plunger with the piston, the urging force of the second spring being smaller than that of the first spring.
Inventors
- 👤 H Kawaguchi
- 👤 R Furukawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:20
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/26
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
191 words
A brake pressure control valve for a vehicle comprising, in combination, a cylinder having an inlet port and an outlet port thereon; a differential piston slidably disposed within said cylinder to subdivide the cylinder interior into first and second pressure chambers facing piston surfaces of different areas and connected reSpectively to a master cylinder through said inlet port and to rear-wheel brake cylinders through said outlet port; valve means cooperable with said piston for controlling the intercommunication of said first and second chambers; first spring means for biasing said piston in a direction to keep said valve means normally open; an assistant plunger slidably engaged within said piston to subdivide the piston interior into third and fourth pressure chambers, said third and fourth chambers always being fluid tight relative to each other, said third chamber being in open communication with said first chamber and said fourth chamber always being connected to said second chamber; and second spring means for normally biasing said plunger in a direction to axially unite said plunger with said piston; the urging force of said second spring means being smaller than that of said first spring means.
Claim 2
Dependent Claim
191 words
A brake pressure control valve for a vehicle comprising, in combination, a cylinder having an inlet port and an outlet port thereon; a differential piston slidably disposed within said cylinder to subdivide the cylinder interior into first and second pressure chambers facing piston surfaces of different areas and connected reSpectively to a master cylinder through said inlet port and to rear-wheel brake cylinders through said outlet port; valve means cooperable with said piston for controlling the intercommunication of said first and second chambers; first spring means for biasing said piston in a direction to keep said valve means normally open; an assistant plunger slidably engaged within said piston to subdivide the piston interior into third and fourth pressure chambers, said third and fourth chambers always being fluid tight relative to each other, said third chamber being in open communication with said first chamber and said fourth chamber always being connected to said second chamber; and second spring means for normally biasing said plunger in a direction to axially unite said plunger with said piston; the urging force of said second spring means being smaller than that of said first spring means.
Claim 3
Dependent Claim
38 words
A brake pressure control valve for a vehicle as claimed in claim 1, wherein said second spring means is a coiled compression spring stretched between said plunger and the interior wall of said cylinder within said fourth chamber.
Claim 4
Dependent Claim
38 words
A brake pressure control valve for a vehicle as claimed in claim 1, wherein said second spring means is a coiled compression spring stretched between said plunger and an inside portion of said piston within said fourth chamber.
Claim 5
Dependent Claim
51 words
A brake pressure control valve for a vehicle as claimed in claim 1, wherein said plunger is provided with a projecting portion extending into said fourth chamber, the displacement of said plunger apart from said piston being regulated by engagement and disengagement of said projecting portion with the cylinder interior wall.
Claim 6
Dependent Claim
33 words
A brake pressure control valve for a vehicle as claimed in claim 1, wherein said third chamber is in open communication with said first chamber through a radial port drilled on said piston.
Claim 7
Dependent Claim
44 words
A brake pressure control valve for a vehicle as claimed in claim 1, wherein said valve means comprises a valve seat disposed on said cylinder between said first and second chambers and a tapered valve face formed on an outer periphery of said piston.
Claim 8
Dependent Claim
40 words
A brake pressure control valve for a vehicle as claimed in claim 1, wherein sealing means is disposed on the outer periphery of said assistant plunger for making said third and fourth pressure chambers fluid tight relative to each other.
Claim 9
Dependent Claim
22 words
A brake pressure control valve for a vehicle as claimed in claim 7, wherein said sealing means is a rubber-like sealing cup.
Claim 10
Dependent Claim
169 words
A brake pressure control valve for a vehicle comprising, in combination, a cylinder having an inlet port and an outlet port thereon; a differential piston slidably disposed within said cylinder to subdivide the cylinder interior into first and second pressure chambers facing piston surfaces of different areas and connected respectively to a master cylinder through said inlet port and to rear-wheel brake cylinders through said outlet port; valve means cooperable with said piston for controlling the intercommunication of said first and second chambers; first spring means for biasing said piston in a direction to keep said valve means normally open; an assistant plunger slidably engaged within said piston to subdivide the piston interior into third and fourth pressure chambers, said third chamber being in open communication with said first chamber and said fourth chamber being connected to said second chamber, wherein said fourth chamber is hydraulically connected to said second chamber through an annular slit passage defined between the outer periphery of said piston and the cylinder interior wall.
Claim 11
Dependent Claim
169 words
A brake pressure control valve for a vehicle comprising, in combination, a cylinder having an inlet port and an outlet port thereon; a differential piston slidably disposed within said cylinder to subdivide the cylinder interior into first and second pressure chambers facing piston surfaces of different areas and connected respectively to a master cylinder through said inlet port and to rear-wheel brake cylinders through said outlet port; valve means cooperable with said piston for controlling the intercommunication of said first and second chambers; first spring means for biasing said piston in a direction to keep said valve means normally open; an assistant plunger slidably engaged within said piston to subdivide the piston interior into third and fourth pressure chambers, said third chamber being in open communication with said first chamber and said fourth chamber being connected to said second chamber, wherein said fourth chamber is hydraulically connected to said second chamber through an annular slit passage defined between the outer periphery of said piston and the cylinder interior wall.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |