US3829168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vehicle wheel brake anti-lock system
Assignee: Robert Bosch GmbH
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Filing: 1973-02-08
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Granted: 1974-08-13
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Expires: 1993-02-08
Abstract
Abstract Acceleration or deceleration of wheels are sensed and a valve which either connects the wheel brake cylinder to a source of pressure fluid or to a drain is controlled in accordance with sensed acceleration or deceleration. A first threshold switch is responsive to wheel deceleration, a second switch is responsive to acceleration, and controls draining of pressurized brake fluid from the wheel brake cylinder.
Inventors
- 👤 E Schnaibel
- 👤 W Gotz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:56
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/17; B60T8/176; B60T8/1761; B60T8/17613
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
316 words
Vehicle wheel pressure fluid brake anti-lock system comprising means (31; 27, 28, 30, 130) sensing wheel speed rate of change; a pressurized fluid brake system (10, 11, 12, 13, 14, 15, 17, 18, 19) having fluid control valve means (13, 20) connecting pressurized fluid to the wheel brake cylinders, or draining pressurized fluid from the brake cylinders; first threshold switch means (41) responsive to wheel deceleration and providing a wheel deceleration signal at a first threshold level; second threshold switch means (42) responsive to wheel acceleration and providing a wheel acceleration signal at a second threshold level; a controlled switch (45) connected to be responsive to said threshold switches (41, 42) to change between two states when the threshold levels of the respective threshold switches are passed and thus storing a representation of said threshold levels, said switch being connected to and controlling operation of said valve means; the switch (45) having a set input (S) and a reset input (R), the first threshold switch (41) being connected to the set input; a timing circuit (35) connected to start a timing interval upon response of the first threshold switch (41); and logic means (36; 37, 38) connecting the output of the second threshold switch (42) and said timing circuit (35) to the reset input (R) of said switch (45) to a. reset the switch (45) during said timing period when the second threshold switch (42) responds, indicative of rapid wheel re-acceleration and hence grip of wheel on the road, to permit rise in braking pressure, and b. if the wheel has not accelerated within said timing period, to cause response of said second threshold switch (42) with said timing period, then control resetting of said switch (45) and hence again permit rise in braking pressure only when acceleration of the wheel has dropped below the second threshold level indicative that acceleration of the wheel is decreasing.
Claim 2
Dependent Claim
316 words
Vehicle wheel pressure fluid brake anti-lock system comprising means (31; 27, 28, 30, 130) sensing wheel speed rate of change; a pressurized fluid brake system (10, 11, 12, 13, 14, 15, 17, 18, 19) having fluid control valve means (13, 20) connecting pressurized fluid to the wheel brake cylinders, or draining pressurized fluid from the brake cylinders; first threshold switch means (41) responsive to wheel deceleration and providing a wheel deceleration signal at a first threshold level; second threshold switch means (42) responsive to wheel acceleration and providing a wheel acceleration signal at a second threshold level; a controlled switch (45) connected to be responsive to said threshold switches (41, 42) to change between two states when the threshold levels of the respective threshold switches are passed and thus storing a representation of said threshold levels, said switch being connected to and controlling operation of said valve means; the switch (45) having a set input (S) and a reset input (R), the first threshold switch (41) being connected to the set input; a timing circuit (35) connected to start a timing interval upon response of the first threshold switch (41); and logic means (36; 37, 38) connecting the output of the second threshold switch (42) and said timing circuit (35) to the reset input (R) of said switch (45) to a. reset the switch (45) during said timing period when the second threshold switch (42) responds, indicative of rapid wheel re-acceleration and hence grip of wheel on the road, to permit rise in braking pressure, and b. if the wheel has not accelerated within said timing period, to cause response of said second threshold switch (42) with said timing period, then control resetting of said switch (45) and hence again permit rise in braking pressure only when acceleration of the wheel has dropped below the second threshold level indicative that acceleration of the wheel is decreasing.
Claim 3
Dependent Claim
78 words
System according to claim 1, wherein the pressurized fluid brake system includes a master brake cylinder (10, 11) a wheel brake cylinders (14, 15) and a fluid sump (17); and wherein the valve means (13, 20) comprises a 3/2 way valve connected in the fluid circuit to connect, when in rest position, the master brake cylinder (10, 11) with the wheel brake cylinders and to connect the wheel brake cylinder to the fluid sump when in operated condition.
Claim 4
Dependent Claim
40 words
System according to claim 2, wherein the first threshold switch (41) controls change of state of said controlled switch (45) in a direction to effect operation of said valve to connect the wheel brake cylinders to the fluid drain (17).
Claim 5
Dependent Claim
43 words
System according to claim 1, wherein logic means (36; 37, 38) connects the inverted output of the second threshold switch (42) and the conjunctive output of said timing circuit (35) and said second threshold switch (42) disjunctively to control said controlled switch (45).
Claim 6
Dependent Claim
79 words
System according to claim 1, for use in an automotive vehicle having a driven shaft (26) and a differential (25) connected to the driven wheels to be braked; and wherein the means sensing the wheel speed rate of change comprises a pulse source (27) associated with said driven shaft (26) and providing an output signal representative of wheel speed, and a differentiator (30) differentiating the wheel speed signal to provide a wheel rate of change of speed output signal.
Claim 7
Dependent Claim
96 words
System according to claim 1, wherein the system is applied to an automotive vehicle having wheels adapted to be braked which can have speeds independent from each other; wherein a transducer (26, 27, 28) is associated with each wheel, and providing an output signal representative of individual wheel speeds; an averaging circuit (154) is provided having the wheel speed signals applied therEto and providing an output signal representative of average wheel speed; and a differentiating circuit (130) is connected to the output of the averaging circuit (154) to provide the wheel speed rate of change signal.
Claim 8
Dependent Claim
26 words
System according to claim 1, further comprising a low pass filter (34) connecting the wheel speed rate of change sensing means (31) to the threshold switches.
Claim 9
Dependent Claim
19 words
System according to claim 7, wherein the upper limiting frequency of the low pass filter is about 18 Hz.
Claim 10
Dependent Claim
60 words
System according to claim 1, comprising two low pass filters (133, 134) having their inputs connected to the wheel speed rate of change sensing means; the first threshold switch (41) being connected to the output of the first low pass filter (133) and the second threshold switch (142) being connected to the output of the second low pass filter (134).
Claim 11
Dependent Claim
48 words
System according to claim 9, wherein the low pass filters have different maximum pass ranges, the upper pass range of the first low pass filter (133) to which the first threshold switch (141) is connected having a lower upper frequency limit than the second low pass filter (134).
Claim 12
Dependent Claim
129 words
System according to claim 6, further comprising an extreme value circuit (155) having the outputs of the wheel speed transducer means (26, 27, 28, 128, 129) applied thereto and providing an output representative of the highest wheel speed; a comparator (156) having the outputs of the averaging circuit (154) and of the extreme value circuit (155) applied thereto and connected to compare said outputs and providing an output signal when the difference between the average speed of the wheels, and the extreme speed of one wheel exceeds a predetermined limit; and connection means (153) controlling the valve means (13) to drain pressurized brake fluid from the brakes when the comparator indicates that a difference between average wheel speed and maximum wheel speed is present which exceeds said predetermined difference.
Claim 13
Dependent Claim
32 words
System according to claim 11, wherein the connection means comprises an OR-gate (153) having one input connected to the comparator and another input connected to the output of said first threshold switch.
Claim 14
Dependent Claim
53 words
System according to claim 6, wherein the averaging circuit comprises a transistor (540) in emitter follower circuit, having an emitter resistor (543); and a resistor, each, (541, 542), connecting the base of the transistor to the respective transducer means (26, 27, 28; 128, 129) providing each a signal representative of respective wheel speed.
Claim 15
Dependent Claim
73 words
System according to claim 11, wherein the extreme value circuit comprises a pair of diodes (551, 552), one each connected to the transducer means (26, 27, 28; 128, 129) providing the wheel speed signals representative of speed of the respective wheels; the diodes being further connected in parallel at their output to provide a signal at their common output which is representative of the maximum signal applied to the inputs of the diodes.
Claim 16
Dependent Claim
83 words
System according to claim 11, wherein the comparator (156) includes an operational amplifier (560) having one input connected to the output of the averaging circuit (154) and the other input to the output of the extreme value circuit (155); a transistor (563) connected to the output of the operational amplifier, the collector of said transistor forming the output of the comparator circuit (156); and a feedback resistor (565) connecting the collector of the transistor and the inverting input of the operational amplifier (560).
Claim 17
Dependent Claim
114 words
System according to claim 1, wherein the controlled switch (45) comprises a monostable multivibrator circuit (45) having an unstable time of a duration which is longer than the expected re-acceleralion of a wheel of the vehicle when vehicle braking is commanded by the vehicle operator, energization of the reset input (R) to reset the monostable circuit to stable state under control of said logic means being in advance of inherent change of state due to the moNostable characteristic of said switch to provide for automatic reset after said unstable time duration, and hence termination of drainage of pressurized brake fluid regardless of presence of energization of the reset input (R) of said switch (45).
Claim 18
Dependent Claim
20 words
System according to claim 16, wherein the unstable time of the monostable circuit (45) is about 400 to 500 milliseconds.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |