EP0448031A1
Expired / Lapsed
EP
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Brake pressure generator
Assignee: Toyota Motor Corp
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Filing: 1991-03-19
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Granted: —
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Expires: 2011-03-19
Abstract
Abstract A pressure generating apparatus for a hydraulic brake system, including a master cylinder (14, 160, 410) having a pressure piston (20, 22, 166, 168, 418, 420) which partially defines a pressure chamber (24, 26, 170, 72, 422, 424) and which is advanced to generate a fluid pressure in the pressure chamber in response to an operation of a brake operating member. The apparatus further includes inhibiting device (80, 90, 96, 182, 188, 196, 470) having a non-operated position for allowing the pressure piston to be advanced, and an operated position for inhibiting the pressure piston from being advanced, and a pressure changing device (20, 22, 24, 26, 112, 116, 122, 126, 130, 132, 166, 168, 170, 172, 224, 226, 228, 232, 240, 242, 490) having a pressure changing chamber (24, 26, 170, 172, 498) communicating with the pressure chamber. The pressure changing device operates to change a volume of the pressure changing chamber and thereby change the pressure chamber pressure. A controller (140, 520) is provided for controlling the inhibiting device and the pressure changing device, to change the pressure in the pressure chamber while the inhibiting device is placed in the operated position.
Inventors
- 👤 Shirou Toyota Jidosha Kabushiki Kaisha Monzaki
- 👤 Harumi Toyota Jidosha Kabushiki Kaisha Ohori
- 👤 Hideyuki Toyota Jidosha Kabushiki Kaisha Aizawa
- 👤 Ryozo Toyota Jidosha Kabushiki Kaisha Saitoh
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 00:09
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/32; B60T8/321; B60T8/3255; B60T8/326; B60T8/3265; B60T11/00; B60T11/10; B60T11/16; B60T11/20; B60T13/00; B60T13/10; B60T13/24; B60T13/46; B60T13/52; B60T13/565; B60T8/34; B60T8/40; B60T8/4004; B60T8/42; B60T8/4208; B60T8/4266; B60T8/48; B60T8/4809; B60T8/4827; B60T8/4863
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
191 words
A pressure generating apparatus for a hydraulically operated brake system, comprising: a master cylinder (14, 160, 410) having a pressure piston (20, 22, 166, 168, 418, 420) which partially defines a pressure chamber (24, 26, 170, 172, 422, 424) and which is advanced to generate a fluid pressure in said pressure chamber in response to an operation of a brake operating member (10, 414); an inhibiting device (80, 90, 96, 182, 188, 196, 470) having a non-operated position for allowing said pressure piston to be advanced, and an operated position for inhibiting said pressure piston from being advanced; a pressure changing device (20, 22, 24, 26, 112, 116, 122, 126, 130, 132, 166, 168, 170, 172, 224, 226, 228, 232, 240, 242, 490) having a pressure changing chamber (24, 26, 170, 172, 498) communicating with said pressure chamber, and operable to change a volume of said pressure changing chamber and thereby change the pressure in said pressure chamber; and a controller (140, 520) for controlling said inhibiting device and said pressure changing device, to change the pressure in said pressure chamber while said inhibiting device is placed in said operated position.
Claim 2
Dependent Claim
91 words
A pressure generating apparatus according to claim 1, wherein said inhibiting device comprises: a movable member (80, 182, 474) interposed between said brake operating member (10, 414) and said pressure piston (20, 22, 166, 168, 418, 420), and advanced in response to the operation of said brake operating member; and inhibiting means (90, 96, 188, 196, 470) normally placed in a non-operated position for allowing advancing and retracting movements of said movable member, said inhibiting means having an operated position for inhibiting at least the advancing movement of said movable member.
Claim 3
Dependent Claim
99 words
A pressure generating apparatus according to claim 2, further comprising a housing (62, 164, 472), and a reservoir (32, 194, 426) communicating with a fluid passage (94, 192, 479), and wherein said movable member comprises a control piston (80, 182, 474) which is fluid-tightly and axially slidably disposed in said housing and which partially defines a control chamber (90, 188, 478) filled with a fluid, such that a volume of said control chamber is reduced by the advancing movement of said control piston, and said inhibiting means comprises a shut-off valve (96, 196, 480) provided in said fluid passage.
Claim 4
Dependent Claim
57 words
A pressure generating apparatus according to claim 3, wherein said inhibiting means further comprises a check valve (100, 202, 482) disposed in parallel with said shut-off valve, said check valve permitting a flow of the fluid from said reservoir to said control chamber and inhibiting a flow of the fluid from said control chamber to said reservoir.
Claim 5
Dependent Claim
47 words
A pressure generating apparatus according to claim 3 or 4, wherein said control piston includes a large-diameter portion and a small-diameter portion disposed in front of said large-diameter portion, said housing and said large-diameter and small-diameter portions cooperating to define an annular chamber as said control chamber.
Claim 6
Dependent Claim
58 words
A pressure generating apparatus according to any one of claims 3-5, further comprising a fail-safe device (262, 304, 308) for inhibiting the advancing movement of said movable member when said inhibiting means is normal and is placed in said operated position, and for allowing said advancing movement when said inhibiting means is abnormally placed in said operated position.
Claim 7
Dependent Claim
48 words
A pressure generating apparatus according to claim 6, wherein said fail-safe device is normally placed in a position for allowing said advancing movement of said movable member, and is operated to a position for inhibiting said advancing movement in response to an operation of said pressure changing device.
Claim 8
Dependent Claim
56 words
A pressure generating apparatus according to claim 7, wherein said fail-safe device comprises a pilot-operated switch valve (262) disposed in parallel to said shut-off valve, said switch valve being closed due to a pilot pressure supplied from said pressure changing device when said pressure changing device is operated to change the pressure in said pressure chamber.
Claim 9
Dependent Claim
113 words
A pressure generating apparatus according to any one of claims 1-8, wherein said pressure changing device comprises: a screw device including an externally threaded member (130, 240, 494) and an internally threaded member (116, 224, 504) which engage each other, one of said externally and internally threaded members being prevented from rotating about an axis thereof; a drive device (112, 122, 126, 226, 228, 232, 492, 500, 502) for rotating the other of said externally and internally threaded members; and a pressure changing piston (20, 22, 242, 496) axially movable with one of said externally and internally threaded members, for changing the volume of said pressure changing chamber (24, 26, 170, 172, 498).
Claim 10
Dependent Claim
86 words
A pressure generating apparatus according to claim 9, wherein said externally and internally threaded members (130, 116) are disposed between said brake operating member (10) and said pressure piston (20, 22) such that said threaded members are axially movable in engagement with each other, the threaded member (116) which is not movable with said pressure changing piston being movable with said movable member (80), said pressure piston (20, 22) and said pressure chamber (24, 26) serving as said pressure changing piston and said pressure changing chamber.
Claim 11
Dependent Claim
122 words
A pressure generating apparatus according to claim 10, wherein said drive device of said pressure changing device comprises a gear (112) which is rotatably and axially immovably supported by a housing of the apparatus and having a splined bore (114), said internally threaded member (116) engaging said splined bore such that said gear and said internally threaded member are axially movable relative to each other and are not rotatable relative to each other, said externally threaded member and said movable member engaging each other such that the externally threaded member and said movable member are axially movable relative to each other and not rotatable relative to each other, said housing preventing said externally threaded member and said movable member from being rotated.
Claim 12
Dependent Claim
48 words
A pressure generating apparatus according to claim 9, wherein said pressure changing piston (242) is opposed to said pressure piston (166, 168), with said pressure chamber (170, 172) interposed between said pressure changing piston and said pressure piston, said pressure chamber also serving as said pressure changing chamber.
Claim 13
Dependent Claim
57 words
A pressure generating apparatus according to claim 9, wherein said pressure changing device (490) and said master cylinder (410) are structurally separated from each other, except that said pressure changing chamber (498) of said pressure changing device and said pressure chamber (422, 424) of said master cylinder communicate with each other through a fluid passage (446, 488).
Claim 14
Dependent Claim
47 words
A pressure generating apparatus according to claim 9, wherein said inhibiting device (470) is disposed coaxially with said master cylinder (410), and said pressure changing device (490) is disposed such that an axis of said pressure changing device is spaced from an axis of said inhibiting device.
Claim 15
Dependent Claim
94 words
A pressure generating apparatus according to claim 9, wherein said drive device comprises: a driving member (124, 230) rotated by a drive source (122, 228, 492); a driven member (126, 232, 500) rotated by said driving member to rotate the threaded member (116, 224, 504) which is not prevented from rotating; and a clutch device (128, 234, 508) interposed between said driving and driven members, and operating to transmit a torque from said driving member to said driven member and prevent the transmission of a torque from said driven member to said driving member.
Claim 16
Dependent Claim
50 words
A pressure generating apparatus according to claim 15, further comprising a stop device (222, 246) for limiting a retracting movement of the threaded member (240) which is rotated with said pressure changing piston (242), said retracting movement causing an increase in the volume of said pressure changing chamber (170, 172).
Claim 17
Dependent Claim
290 words
A hydraulically operated anti-lock brake system for a motor vehicle having a wheel (38, 40, 52, 54, 436, 438, 452, 454), comprising: a master cylinder (14, 160, 410) having a pressure piston (20, 22, 166, 168, 418, 420) which partially defines a pressure chamber (24, 26, 170, 172, 422, 424) and which is advanced to generate a fluid pressure in said pressure chamber in response to an operation of a brake operating member (10, 414); a wheel cylinder (42, 44, 56, 58, 440, 442, 456, 458) operated by said fluid pressure to apply a brake to said wheel; slip detecting means (142, 144, 146, 148, 520, 524, 526, 528, 530) for generating an output signal indicative of the presence of an excessive amount of slipping of said wheel on a road surface; an inhibiting device (80, 90, 96, 182, 188, 196, 470) having a non-operated position for allowing said pressure piston to be advanced, and an operated position for inhibiting said pressure piston from being advanced; a pressure changing device (20, 22, 24, 26, 112, 116, 122, 126, 130, 132, 166, 168, 170, 172, 224, 226, 228, 232, 240, 242, 490) having a pressure changing chamber (24, 26, 170, 172, 498) communicating with said pressure chamber, and operable to change a volume of said pressure changing chamber and thereby change the pressure in said pressure chamber; and a controller (140, 520) for normally holding said inhibiting device in said non-operated position, and placing said inhibiting device in said operated position and controlling said pressure changing device, in response to said output signal of said slip detecting means, so as to change the pressure in said pressure chamber for maintaining an amount of slipping of said wheel within an optimum range.
References Cited (Backward Citations)
FR2565185A1
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FR2578500A1
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EP0292648A2
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EP0298617A2
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EP0411320A1
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