CA1115750A - Braking arrangement with rotational rate of change sensor - Google Patents
Braking arrangement with rotational rate of change sensorInfo
- Publication number
- CA1115750A CA1115750A CA314,943A CA314943A CA1115750A CA 1115750 A CA1115750 A CA 1115750A CA 314943 A CA314943 A CA 314943A CA 1115750 A CA1115750 A CA 1115750A
- Authority
- CA
- Canada
- Prior art keywords
- sensor
- rotating member
- condition
- wheel
- vehicle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000008859 change Effects 0.000 title description 7
- 230000035945 sensitivity Effects 0.000 claims abstract description 15
- 230000004044 response Effects 0.000 claims abstract description 14
- 230000005540 biological transmission Effects 0.000 claims abstract description 11
- 230000011664 signaling Effects 0.000 claims abstract description 8
- 230000006872 improvement Effects 0.000 claims abstract description 6
- 230000008878 coupling Effects 0.000 claims description 15
- 238000010168 coupling process Methods 0.000 claims description 15
- 238000005859 coupling reaction Methods 0.000 claims description 15
- 239000000725 suspension Substances 0.000 claims description 6
- 230000004043 responsiveness Effects 0.000 abstract description 7
- 239000012530 fluid Substances 0.000 description 10
- 230000000694 effects Effects 0.000 description 4
- 208000036366 Sensation of pressure Diseases 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 239000010720 hydraulic oil Substances 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/18—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to vehicle weight or load, e.g. load distribution
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/72—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration responsive to a difference between a speed condition, e.g. deceleration, and a fixed reference
- B60T8/74—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration responsive to a difference between a speed condition, e.g. deceleration, and a fixed reference sensing a rate of change of velocity
Landscapes
- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Regulating Braking Force (AREA)
- Braking Arrangements (AREA)
Abstract
Abstract of the Disclosure In the combination of a rotating member such as in automotive vehicle wheel, a brake operative for slowing the rotating member or wheel, and a sensor for signalling any occurrence of an excessive rate of retarda-tion of the rotating member or wheel, an improvement which facilitates optimum response of the sensor by varying the sensitivity or responsiveness of the sensor upon variations in a vehicle operating condition such as the weight imposed on the rotating member or wheel or the brak-ing pressure. In specific forms disclosed, variation in sensitivity of the sensor is accomplished by a variable ratio transmission means mechanically interposed between the sensor and the rotating member or wheel and which is responsive to vehicle operating conditions
Description
1575~
IMPROVED BRAKING ARRANGEMENT WITH
ROTATIONAL RATE OF CHANGE SENSOR
.............................................. ~' Te'chnical'Fi'eld and Background of In~ention ;::
It has been noted as being desirable or neces-` sary in a number of apparatus and processes to sense the rate'of change of changing rotational speeds of a rota- -tional element. One example of such a need is found inconnection with the use of brakes for slowing a rotat-ing member such as an automotive vehicle wheel. As has been pointed out, sensing the rate of change of changing rotational speeds of a braked rotating member such as an automotive vehicle wheeI can be used in con-junction with'appropriate arrangements for optimizing braking effects. A ~ariety of approaches to sensing rate of change'of changing rotational speeds and/or vehicle whe'el slip has been proposed heretofore, as the in~terested reader will discover from prior patents, references cited therein, and references cited during the prosecution of thé applications which resulted in those cited patents. Interested readers are referred to such prior patents for a more complete discussion of a range of types of sensors.
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It will be understood that ~he sensitivity or responsiveness of sensors responsive to wheel slip and/or rates of change of changing rotational speeds of a rotata-ble element and/or rates of retardation is an important element in determining the performance of any system proposing to obtain control of braking and driving pro-cesses. While a competent designer knowledgeable in the arts pertinent to the sensors referred to is able to design and have made and place into use sensors effective to accomplish control by signalling occurences of excessive rates of retardation, it has been hereto-fore recognized as difficult to accomplish all of sub-stantial sensitivity or responsiveness of a sensor, and ruggedness in use, and optimization of response to vary-ing brake operating conditions. Inevitably, the skilled designer must compromise among the desired goals, with the compromises made favoring certain desired character-istics over other characteristics which are desired but perhaps unattainable.
It has been recognized heretofore that optimal sensitivity or responsiveness of a sensor may be facili-tated by rendering the sensor responsive to a vehicle condition. In connection with certain speciic sensor structures and methods, it has been recognized that such optimal operation can be facilitated by adjusting spring tensions in such a way as to controllably vary certain normally fixed sensor settings. While such approaches are well adapted to the specific sensor structures for which they have been proposed, it is deemed desirable to facilitate optimal response of sensors irrespective of the specific form of sensor employed.
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-Brief Summary of Invention With the above discussion particularly in mind, it is an object of the present invention to provide an improvement for the combination of a rotating member, a brake for slowing the rotating member and a sensor for signalling any occurrence of an excessive rate of retarda-tion of the rotating member which facilitates optimizing response of the sensor without regard to the specific form of the sensor. In realizing this object of the present invention, a coupling means is operatively interposed between the sensor and the rotating member and rendered operatively responsive for varying sensitivity or responsiveness of the sensor.
Yet a further object of the present invention is to facilitate improving the responsiveness and sensi-tivity of a sensor provided in an automotive vehicle and of the type which is mechanically connected to a rotating member such as a vehicle wheel. In realizing this object of the present invention, the coupling means takes the form of a variable ratio transmission means through which rotational movement is transmitted from the rotating member or wheel to the sensor. By varying the ratio of transmission in response to at least one selected vehicle operating condition such as braking pressure conditions and weight load conditions, optimization of sensor response is facilitatèd.
~ , , .
-~$~5~'3 Brief Description of. Drawings Some of the objects of the invention having been stated, other objects will appear as the description pro- :~
ceeds, when taken in connection with the accompanying drawings, in which --Figure 1 is an elevation view, partially in section and partially schematic, of a braking arrange-ment in accordance with the present invention; and Figure 2 is a schematic diagram of the apparatus of Figure 1.
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Detailed ~escription of the Invention While the present invention will be described hereinafter with particular reference to the accompanying drawings, in which certain forms of the present invention S are shown, it is to be recognized at the outset of the following description that persons knowledgeable in the appropriate arts of brake control will be able to depart from the specific arrangements here shown and to be described while still taking advantage of the important characteristics of the present invention. Accordingly, the description which follows is to be understood as a broad teaching of the present invention and not as limit-ing upon the scope of this invention.
Referring now more particularly to Figure 1, the present invention is there disclosed in the combination of a rotating member, generally indicated at 10, which takes the particular form of a wheel of an automotive vehicle.
A brake is provided, as generally indicated at 11, which is operative for slowing the rotating member. Specific arrangements for brakes for wheels of automotive vehicles are well known to persons skilled in the applicable mechanical arts, and accordingly will not here be de-scribed in great detail. A sensor, generally indicated at 12, is operatively coupled to the rotating member 10 for signalling any occurence of an excessive rate of retardation of the wheel. The sensor may, if desired, take the form of those disclosed in United States Patent 4,061,212. However, it is specifically contemplated for the present invention that the sensor 12 may take a wide range of other forms known to or conceived by persons skilled in the applicable arts. In the particular form shown, the sensor 12 is operatively mechanically coupled ~: 1 ~ ' ~ ; ,',' ''` ;
1~57~
to t}le r~)~ati,ncJ mcmber 10 by means of a pair of gears 1~, 15 all(l input shaft 16.
Operatively interposed between sensor 12 and the ro~aLiny member 10 is a coupling means generally indicate('l at 18. In the form illustrated, and as de-scri~ed more p~rticularly hereinafter, the coupling mealls 18 is a mec}lanical, variable ratio transmission means for transmitting rotation from the input shaft 16 to an outuut shaft 16A and thence to the sensor 12.
Variable ratio transmission means contemplated as accepta-ble for usc as the coupling means lB of the present inven- '~
tion may take a variety of different forms known to persons skilled in the applicable mechanical arts, and it is con-templated that a wide range of such mechanisms would be acceptable in the context of the present invention. By way of example only, and not by way of limitation, the varia-ble ratio transmission means may take one of the forms sug-gested ~y Arter United States Patent 1,718,846; Dodge United States Patent 2 J 164,504; Arter United States Patent 2,535,028; or Floyd United States Patent 3,071,018, to any one or more of which the interested reader is ~, referred. ' , ' In the form shown, the couplin~ means 18 is provided with an operating lever 19 by which the ratio of ';
transmission of rotation through the coupling means 18 may b,e selectively varied. In accordance with the pre-sent invention, the position of the lever 19 is controlled by a vehicle operating condition, in such a manner that the sensor 12 is driven at a rotational speed which is in proportion to the rotational speed to the rotating member 10 or wheel, with the,ratio of the proportional sensor rotational speed being varied. In particular, it is contemplated for the arrangement of Figure 1 that the . : . . ::: -:
: . ~
.. ..
' , ratio of proportional sensor rotational speed be governed by a factor which influences brake operation, as pointed out hereinafter.
As herein used, the "sensitivity" or "respon-siveness" of a sensor is intended to reflect, at least inpart, the so-called g-value of a sensor as related to its use in brake control systems for ~ehicles is defined with reference to the vehicle speed change which causes an alteration in the rotational speed of a flyweight.
High retardation values are stated to correspond to high g-values. Normal g-value settings for sensors usable under good road surface conditions are between 0.7 and 1.5 g, where the average figure for the acceleration of objects in the gravitational field of the earth, namely 9.81 m/sec2, is used as a reference. The meaning of the term "g-value" may also be understood from graphical representations of vehicle speed, flyweight speed, and vehicle wheel speed to be found in prior publications.
In such graphs, the slopes of lines indicating speeds, or the negative derivatives thereof, are measures of retardation expressed in appropriate units.
Frictional conditions existing between a wheel and a road surace are one of two important varying factors which, in accordance with the present invention, may have influence on the sensitivity of sensors for a particular vehicle. The second factor is vehicle loading, and Figure 2 illustrates one particular arrangement in which the two variables can affect the adjustment of a sensor. More particularly, Figure 2 includes a schematic representation of a source 50 of a pressurized braking fluid, such as a master cylinder supplying pressurized hydraulic oil, and a brake force modulator 51 for con-trolling vehicle wheel braking effects. An appropriate conduit 52 connects the pressure source 50 with the 35 modulator 51 and a further conduit 54 supplies pres-surized braking fluid to a vehicle wheel brake 55. Pres-sure supplied from the master cylinder 50, whether or not modulated or reduced by the effect of the modulator ,. , . ~ . ....
- - : . ~
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.
51, is supplied through the conduit 52 to a cylinder 56 enclosing a piston 58 which operates a piston rod 59 and is acted on by a return spring 60. The position of the rod 59 controls the position of the operating lever 19 of the coupling means 18. The cylinder 56 is arranged to slide axially along two guides 64, 65. Further, the cylin~er 56, is operatively connected with a Bowden wire 66, the other end of which is connected to a lever 68 mounted for movement about a pivot 69, fixed in the frame 70 of the vehicle, in response to relative displacement of a portion ~f the vehicle frame 70 and the vehicle suspension 71. As vehicle load increases, the vehicle suspension moves relative to the frame, causing movement to be transmitted through the lever 68 and Bowden wire 66 to the cylinder 56.
When the brakes are not actuated and no pres-sure is transmitted from the master cylinder 50 through the modulator 51 to the brake cylinder 55 of the vehicle wheel and the control cylinder 56, the return spring 60 ur~es the piston 58 to the right in Figure 2. When the master cylinder 50 is actuated, braking fluid pres-sure rises in the cylinder 56, the force applied to the piston 58 overcomes the force of the return spring 60, and the piston 58 and rod 59 are moved (to the left of Figure 2). A point is reached at an increased brake fluid pressure at which the vehicle wheel tends to lock and the sensor generates a signal to the modulator to lower brake pressure. The brake pressure at which the sensor starts to signal is a measure of the frictional conditions existing between the wheel and the road surface and the system, as here described, has thus adjusted the sensor to a sensitivity suitable for the existing conditions.
Compensation solely in response to braking fluid pressures will be found, in some circumstances, to be sufficient for vehicles such as heavy passenger cars in which wheel pressure does not vary greatly in .. . . .
, :, .
l~lS~
g response to vehicle loading. However, with cargo trucks and small cars of relatively low weight, wheel pressures may vary considerably in response to vehicle load. It is with such vehicles that the efficiency and vexsatility of a brake control system is substantially enhanced by using both vehicle load conditions and hydraulic braking fluid pressures as control parameters for g-value settings. In such instances and in the arrangement illustrated in Figures 1 and 2, it i5 cor-rect to say that the load dependent adjustment is super-posed on the fluid pressure dependent adjustment.
Brake force modulating systems have been pro-posed for compressed air brake systems in which air pressure is not modulated but a hydraulic system is 15 provided to oppose or counteract the brake force exerted by the "normal" compressed air brake system. The pres-ent invention is contemplated as being adaptable to such arrangements, with it being understood that in such arrangements the cylinder 56, piston 58, piston rod 59 20 and return spring 60 may be replaced by a differential pressure cylinder arrangement in which the piston is bal-anced between the total air pressure applied to a wheel cylinder and the counteracting hydraulic fluid pressure.
In the event that the pressure ranges for the air and 25 hydraulic fluid are of different magnitudes, the cylinder arrangement may employ two interconnected pistons of different diameters in order to accommodate the balanc-ing effect. Normally, the "coUnteracting" hydraulic fluid pressure would be contemplated as being higher than the 30 "normal" air brake pressure and, for that reason, the pis-ton responding to air brake pressure may be the larger one.
In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used 35 in a gener~c and descriptive sense only and not for purposes of limitation.
...... . . .
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: : , ~ - . :,.: - , , . :,
IMPROVED BRAKING ARRANGEMENT WITH
ROTATIONAL RATE OF CHANGE SENSOR
.............................................. ~' Te'chnical'Fi'eld and Background of In~ention ;::
It has been noted as being desirable or neces-` sary in a number of apparatus and processes to sense the rate'of change of changing rotational speeds of a rota- -tional element. One example of such a need is found inconnection with the use of brakes for slowing a rotat-ing member such as an automotive vehicle wheel. As has been pointed out, sensing the rate of change of changing rotational speeds of a braked rotating member such as an automotive vehicle wheeI can be used in con-junction with'appropriate arrangements for optimizing braking effects. A ~ariety of approaches to sensing rate of change'of changing rotational speeds and/or vehicle whe'el slip has been proposed heretofore, as the in~terested reader will discover from prior patents, references cited therein, and references cited during the prosecution of thé applications which resulted in those cited patents. Interested readers are referred to such prior patents for a more complete discussion of a range of types of sensors.
.
q~
.. ..
.. : . - ,, .
:`
1~5~7~l~
It will be understood that ~he sensitivity or responsiveness of sensors responsive to wheel slip and/or rates of change of changing rotational speeds of a rotata-ble element and/or rates of retardation is an important element in determining the performance of any system proposing to obtain control of braking and driving pro-cesses. While a competent designer knowledgeable in the arts pertinent to the sensors referred to is able to design and have made and place into use sensors effective to accomplish control by signalling occurences of excessive rates of retardation, it has been hereto-fore recognized as difficult to accomplish all of sub-stantial sensitivity or responsiveness of a sensor, and ruggedness in use, and optimization of response to vary-ing brake operating conditions. Inevitably, the skilled designer must compromise among the desired goals, with the compromises made favoring certain desired character-istics over other characteristics which are desired but perhaps unattainable.
It has been recognized heretofore that optimal sensitivity or responsiveness of a sensor may be facili-tated by rendering the sensor responsive to a vehicle condition. In connection with certain speciic sensor structures and methods, it has been recognized that such optimal operation can be facilitated by adjusting spring tensions in such a way as to controllably vary certain normally fixed sensor settings. While such approaches are well adapted to the specific sensor structures for which they have been proposed, it is deemed desirable to facilitate optimal response of sensors irrespective of the specific form of sensor employed.
. .
- : :
.: ` .',. ' ' " ' ' , .
' .
. ' ~, , :
~ ' ~ ~.15 . ~ ~
-Brief Summary of Invention With the above discussion particularly in mind, it is an object of the present invention to provide an improvement for the combination of a rotating member, a brake for slowing the rotating member and a sensor for signalling any occurrence of an excessive rate of retarda-tion of the rotating member which facilitates optimizing response of the sensor without regard to the specific form of the sensor. In realizing this object of the present invention, a coupling means is operatively interposed between the sensor and the rotating member and rendered operatively responsive for varying sensitivity or responsiveness of the sensor.
Yet a further object of the present invention is to facilitate improving the responsiveness and sensi-tivity of a sensor provided in an automotive vehicle and of the type which is mechanically connected to a rotating member such as a vehicle wheel. In realizing this object of the present invention, the coupling means takes the form of a variable ratio transmission means through which rotational movement is transmitted from the rotating member or wheel to the sensor. By varying the ratio of transmission in response to at least one selected vehicle operating condition such as braking pressure conditions and weight load conditions, optimization of sensor response is facilitatèd.
~ , , .
-~$~5~'3 Brief Description of. Drawings Some of the objects of the invention having been stated, other objects will appear as the description pro- :~
ceeds, when taken in connection with the accompanying drawings, in which --Figure 1 is an elevation view, partially in section and partially schematic, of a braking arrange-ment in accordance with the present invention; and Figure 2 is a schematic diagram of the apparatus of Figure 1.
, . ~ ~ , . . .
,- ;, . : .
- . . .
~ , , :
15~5~
Detailed ~escription of the Invention While the present invention will be described hereinafter with particular reference to the accompanying drawings, in which certain forms of the present invention S are shown, it is to be recognized at the outset of the following description that persons knowledgeable in the appropriate arts of brake control will be able to depart from the specific arrangements here shown and to be described while still taking advantage of the important characteristics of the present invention. Accordingly, the description which follows is to be understood as a broad teaching of the present invention and not as limit-ing upon the scope of this invention.
Referring now more particularly to Figure 1, the present invention is there disclosed in the combination of a rotating member, generally indicated at 10, which takes the particular form of a wheel of an automotive vehicle.
A brake is provided, as generally indicated at 11, which is operative for slowing the rotating member. Specific arrangements for brakes for wheels of automotive vehicles are well known to persons skilled in the applicable mechanical arts, and accordingly will not here be de-scribed in great detail. A sensor, generally indicated at 12, is operatively coupled to the rotating member 10 for signalling any occurence of an excessive rate of retardation of the wheel. The sensor may, if desired, take the form of those disclosed in United States Patent 4,061,212. However, it is specifically contemplated for the present invention that the sensor 12 may take a wide range of other forms known to or conceived by persons skilled in the applicable arts. In the particular form shown, the sensor 12 is operatively mechanically coupled ~: 1 ~ ' ~ ; ,',' ''` ;
1~57~
to t}le r~)~ati,ncJ mcmber 10 by means of a pair of gears 1~, 15 all(l input shaft 16.
Operatively interposed between sensor 12 and the ro~aLiny member 10 is a coupling means generally indicate('l at 18. In the form illustrated, and as de-scri~ed more p~rticularly hereinafter, the coupling mealls 18 is a mec}lanical, variable ratio transmission means for transmitting rotation from the input shaft 16 to an outuut shaft 16A and thence to the sensor 12.
Variable ratio transmission means contemplated as accepta-ble for usc as the coupling means lB of the present inven- '~
tion may take a variety of different forms known to persons skilled in the applicable mechanical arts, and it is con-templated that a wide range of such mechanisms would be acceptable in the context of the present invention. By way of example only, and not by way of limitation, the varia-ble ratio transmission means may take one of the forms sug-gested ~y Arter United States Patent 1,718,846; Dodge United States Patent 2 J 164,504; Arter United States Patent 2,535,028; or Floyd United States Patent 3,071,018, to any one or more of which the interested reader is ~, referred. ' , ' In the form shown, the couplin~ means 18 is provided with an operating lever 19 by which the ratio of ';
transmission of rotation through the coupling means 18 may b,e selectively varied. In accordance with the pre-sent invention, the position of the lever 19 is controlled by a vehicle operating condition, in such a manner that the sensor 12 is driven at a rotational speed which is in proportion to the rotational speed to the rotating member 10 or wheel, with the,ratio of the proportional sensor rotational speed being varied. In particular, it is contemplated for the arrangement of Figure 1 that the . : . . ::: -:
: . ~
.. ..
' , ratio of proportional sensor rotational speed be governed by a factor which influences brake operation, as pointed out hereinafter.
As herein used, the "sensitivity" or "respon-siveness" of a sensor is intended to reflect, at least inpart, the so-called g-value of a sensor as related to its use in brake control systems for ~ehicles is defined with reference to the vehicle speed change which causes an alteration in the rotational speed of a flyweight.
High retardation values are stated to correspond to high g-values. Normal g-value settings for sensors usable under good road surface conditions are between 0.7 and 1.5 g, where the average figure for the acceleration of objects in the gravitational field of the earth, namely 9.81 m/sec2, is used as a reference. The meaning of the term "g-value" may also be understood from graphical representations of vehicle speed, flyweight speed, and vehicle wheel speed to be found in prior publications.
In such graphs, the slopes of lines indicating speeds, or the negative derivatives thereof, are measures of retardation expressed in appropriate units.
Frictional conditions existing between a wheel and a road surace are one of two important varying factors which, in accordance with the present invention, may have influence on the sensitivity of sensors for a particular vehicle. The second factor is vehicle loading, and Figure 2 illustrates one particular arrangement in which the two variables can affect the adjustment of a sensor. More particularly, Figure 2 includes a schematic representation of a source 50 of a pressurized braking fluid, such as a master cylinder supplying pressurized hydraulic oil, and a brake force modulator 51 for con-trolling vehicle wheel braking effects. An appropriate conduit 52 connects the pressure source 50 with the 35 modulator 51 and a further conduit 54 supplies pres-surized braking fluid to a vehicle wheel brake 55. Pres-sure supplied from the master cylinder 50, whether or not modulated or reduced by the effect of the modulator ,. , . ~ . ....
- - : . ~
~ : . -:, : ' ~ :.~ :
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.
51, is supplied through the conduit 52 to a cylinder 56 enclosing a piston 58 which operates a piston rod 59 and is acted on by a return spring 60. The position of the rod 59 controls the position of the operating lever 19 of the coupling means 18. The cylinder 56 is arranged to slide axially along two guides 64, 65. Further, the cylin~er 56, is operatively connected with a Bowden wire 66, the other end of which is connected to a lever 68 mounted for movement about a pivot 69, fixed in the frame 70 of the vehicle, in response to relative displacement of a portion ~f the vehicle frame 70 and the vehicle suspension 71. As vehicle load increases, the vehicle suspension moves relative to the frame, causing movement to be transmitted through the lever 68 and Bowden wire 66 to the cylinder 56.
When the brakes are not actuated and no pres-sure is transmitted from the master cylinder 50 through the modulator 51 to the brake cylinder 55 of the vehicle wheel and the control cylinder 56, the return spring 60 ur~es the piston 58 to the right in Figure 2. When the master cylinder 50 is actuated, braking fluid pres-sure rises in the cylinder 56, the force applied to the piston 58 overcomes the force of the return spring 60, and the piston 58 and rod 59 are moved (to the left of Figure 2). A point is reached at an increased brake fluid pressure at which the vehicle wheel tends to lock and the sensor generates a signal to the modulator to lower brake pressure. The brake pressure at which the sensor starts to signal is a measure of the frictional conditions existing between the wheel and the road surface and the system, as here described, has thus adjusted the sensor to a sensitivity suitable for the existing conditions.
Compensation solely in response to braking fluid pressures will be found, in some circumstances, to be sufficient for vehicles such as heavy passenger cars in which wheel pressure does not vary greatly in .. . . .
, :, .
l~lS~
g response to vehicle loading. However, with cargo trucks and small cars of relatively low weight, wheel pressures may vary considerably in response to vehicle load. It is with such vehicles that the efficiency and vexsatility of a brake control system is substantially enhanced by using both vehicle load conditions and hydraulic braking fluid pressures as control parameters for g-value settings. In such instances and in the arrangement illustrated in Figures 1 and 2, it i5 cor-rect to say that the load dependent adjustment is super-posed on the fluid pressure dependent adjustment.
Brake force modulating systems have been pro-posed for compressed air brake systems in which air pressure is not modulated but a hydraulic system is 15 provided to oppose or counteract the brake force exerted by the "normal" compressed air brake system. The pres-ent invention is contemplated as being adaptable to such arrangements, with it being understood that in such arrangements the cylinder 56, piston 58, piston rod 59 20 and return spring 60 may be replaced by a differential pressure cylinder arrangement in which the piston is bal-anced between the total air pressure applied to a wheel cylinder and the counteracting hydraulic fluid pressure.
In the event that the pressure ranges for the air and 25 hydraulic fluid are of different magnitudes, the cylinder arrangement may employ two interconnected pistons of different diameters in order to accommodate the balanc-ing effect. Normally, the "coUnteracting" hydraulic fluid pressure would be contemplated as being higher than the 30 "normal" air brake pressure and, for that reason, the pis-ton responding to air brake pressure may be the larger one.
In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used 35 in a gener~c and descriptive sense only and not for purposes of limitation.
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-,. :: . : .... :. :
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Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In the combination of a rotating member, a brake operative for slowing the rotating member, and a sensor opera-tively coupled to the rotating member for signalling any occur-rence of an excessive rate of retardation of the rotating member, an improvement which facilitates optimal response of said sensor comprising mechanical coupling means operatively interposed between said sensor and said rotating member and operatively responsive to a predetermined condition for varying the sensiti-vity of said sensor upon variations in said condition, said coupling means comprising a variable ratio transmission means operatively responsive to at least one predetermined condition selected from a weight load condition and a braking pressure condition.
2. In an automotive vehicle having a rotating wheel, a brake operative for slowing the rotating wheel, and a sensor operatively coupled to the wheel for signalling any occurrence of an excessive rate of retardation of the wheel, an improvement which facilitates optimal response of said sensor comprising mechanical coupling means operatively interposed between said sensor and said rotating member and operatively responsive to a vehicle operating condition for varying the sensitivity of said sensor upon variations in said condition, said coupling means comprising a variable ratio transmission means operatively responsive to at least one predetermined condition selected from a weight load condition and a braking pressure condition.
3. In the combination of a rotating member, a brake operative for slowing the rotating member, and a sensor mechanically connected to the rotating member for rotation at speeds proportionate to the rotating member speeds and for sig-nalling any occurrence of an excessive rate or retardation of the rotating member, an improvement which facilitates optimal response of said sensor comprising coupling means mechanically interposed between said sensor and said rotating member and operatively responsive to at least one predetermined condition selected from a weight-load condition and a braking pressure condition for varying the sensitivity of said sensor upon varia-tions in said condition.
4. In an automotive vehicle having a rotating wheel, a brake operative for slowing the rotating wheel, and a sensor mechanically connected to the rotating wheel for rotation at speeds proportionate to the rotating wheel speeds and for signalling any occurrence of an excessive rate of retardation of the rotating wheel, an improvement which facilitates optimal response of said sensor comprising mechanical coupling means operatively interposed between said sensor and said rotating wheel and operatively responsive to at least one vehicle operat-ing condition selected from a weight-load condition and a braking pressure condition for varying the sensitivity of said sensor upon variations in said condition.
5. Apparatus according to claim 2 or 4 further compris-ing suspension means for mounting said rotating wheel and for transferring vehicle weight thereto and wherein said coupling means comprises a variable ratio transmission means operatively connected to said suspension means and responsive to the position thereof for varying the ratio of proportional sensor rotational speed.
6. Apparatus according to one of claims 2 and 4 further comprising suspension means for mounting said rotating wheel and for transferring vehicle weight thereto and wherein said coupling means comprises a variable ratio transmission means operatively connected to said suspension means and responsive to the position thereof for increasing sensor sensitivity upon an increase in vehicle load.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7712342A SE430401B (en) | 1977-11-01 | 1977-11-01 | BEWARE OF RECOGNITION AND SIGNAL OF RETARDATION |
| SE7712342-0 | 1977-11-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1115750A true CA1115750A (en) | 1982-01-05 |
Family
ID=20332744
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA314,943A Expired CA1115750A (en) | 1977-11-01 | 1978-10-30 | Braking arrangement with rotational rate of change sensor |
Country Status (17)
| Country | Link |
|---|---|
| JP (1) | JPS5489165A (en) |
| AR (1) | AR222641A1 (en) |
| AU (1) | AU527844B2 (en) |
| BE (1) | BE871686A (en) |
| BR (1) | BR7807205A (en) |
| CA (1) | CA1115750A (en) |
| DE (1) | DE2847328A1 (en) |
| ES (1) | ES474712A1 (en) |
| FR (1) | FR2407100A1 (en) |
| GB (1) | GB2023246B (en) |
| IT (1) | IT1100048B (en) |
| MX (1) | MX147107A (en) |
| NL (1) | NL7810815A (en) |
| PL (1) | PL210609A1 (en) |
| PT (1) | PT68723A (en) |
| SE (2) | SE430401B (en) |
| SU (1) | SU1189333A3 (en) |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1028154B (en) * | 1955-12-09 | 1958-04-17 | Knorr Bremse Gmbh | Coupling device on anti-skid controllers |
| DE1176010B (en) * | 1961-01-05 | 1964-08-13 | Daimler Benz Ag | Device to prevent the vehicle wheels from locking up |
| GB1171531A (en) * | 1967-02-10 | 1969-11-19 | Automotive Prod Co Ltd | Improvements in and relating to Fluid Pressure Braking Systems |
| DE1907392C3 (en) * | 1969-02-14 | 1974-01-31 | Daimler-Benz Ag, 7000 Stuttgart | Signal transmitters for vehicle wheels, in particular for brake slip control systems in motor vehicles |
| DE1924346A1 (en) * | 1969-05-13 | 1970-11-26 | Teves Gmbh Alfred | Brake slip regulator |
| US3600043A (en) * | 1969-07-07 | 1971-08-17 | Bendix Corp | Antiskid brake system utilizing a pair of vortex valves |
| DE2114531B2 (en) * | 1971-03-25 | 1973-08-30 | ACCELERATOR | |
| GB1376042A (en) * | 1972-05-30 | 1974-12-04 | Gkn Transmissions Ltd | Braking systems |
| US3833097A (en) * | 1973-09-26 | 1974-09-03 | Holst Jan Olof Martin | Anti-locking arrangement for fluid pressure actuated brake |
-
1977
- 1977-11-01 SE SE7712342A patent/SE430401B/en not_active IP Right Cessation
-
1978
- 1978-10-23 SE SE7811021A patent/SE430404B/en not_active IP Right Cessation
- 1978-10-30 PT PT68723A patent/PT68723A/en unknown
- 1978-10-30 CA CA314,943A patent/CA1115750A/en not_active Expired
- 1978-10-30 AU AU41166/78A patent/AU527844B2/en not_active Expired
- 1978-10-30 PL PL21060978A patent/PL210609A1/en unknown
- 1978-10-31 BR BR7807205A patent/BR7807205A/en unknown
- 1978-10-31 DE DE19782847328 patent/DE2847328A1/en not_active Ceased
- 1978-10-31 NL NL7810815A patent/NL7810815A/en not_active Application Discontinuation
- 1978-10-31 MX MX175464A patent/MX147107A/en unknown
- 1978-10-31 IT IT29307/78A patent/IT1100048B/en active
- 1978-10-31 ES ES474712A patent/ES474712A1/en not_active Expired
- 1978-10-31 GB GB7842569A patent/GB2023246B/en not_active Expired
- 1978-10-31 BE BE191465A patent/BE871686A/en not_active IP Right Cessation
- 1978-10-31 AR AR274300A patent/AR222641A1/en active
- 1978-10-31 FR FR7830810A patent/FR2407100A1/en active Granted
- 1978-11-01 JP JP13511278A patent/JPS5489165A/en active Pending
- 1978-11-01 SU SU782719397A patent/SU1189333A3/en active
Also Published As
| Publication number | Publication date |
|---|---|
| NL7810815A (en) | 1979-05-03 |
| GB2023246A (en) | 1979-12-28 |
| BE871686A (en) | 1979-02-15 |
| GB2023246B (en) | 1982-06-09 |
| MX147107A (en) | 1982-10-06 |
| FR2407100B1 (en) | 1983-07-08 |
| SU1189333A3 (en) | 1985-10-30 |
| SE430404B (en) | 1983-11-14 |
| AU527844B2 (en) | 1983-03-24 |
| SE7712342L (en) | 1979-05-02 |
| AR222641A1 (en) | 1981-06-15 |
| PT68723A (en) | 1978-11-01 |
| IT1100048B (en) | 1985-09-28 |
| PL210609A1 (en) | 1979-09-10 |
| FR2407100A1 (en) | 1979-05-25 |
| BR7807205A (en) | 1979-06-12 |
| SE7811021L (en) | 1979-05-02 |
| IT7829307A0 (en) | 1978-10-31 |
| DE2847328A1 (en) | 1979-05-10 |
| ES474712A1 (en) | 1980-01-16 |
| SE430401B (en) | 1983-11-14 |
| AU4116678A (en) | 1980-05-08 |
| JPS5489165A (en) | 1979-07-14 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |