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WO1986001162A1 - Ensemble levier avec modification de la force requise - Google Patents

Ensemble levier avec modification de la force requise Download PDF

Info

Publication number
WO1986001162A1
WO1986001162A1 PCT/US1984/001703 US8401703W WO8601162A1 WO 1986001162 A1 WO1986001162 A1 WO 1986001162A1 US 8401703 W US8401703 W US 8401703W WO 8601162 A1 WO8601162 A1 WO 8601162A1
Authority
WO
WIPO (PCT)
Prior art keywords
lever
force
cam surface
set forth
lever assembly
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.)
Ceased
Application number
PCT/US1984/001703
Other languages
English (en)
Inventor
James G. Starling
Bertwin E. Behrends
Charles E. Holzinger
David S. Ohaver
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar Inc
Original Assignee
Caterpillar Tractor Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Caterpillar Tractor Co filed Critical Caterpillar Tractor Co
Publication of WO1986001162A1 publication Critical patent/WO1986001162A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
    • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
    • B60T11/103—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic in combination with other control devices
    • 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
    • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
    • B60T11/04—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting mechanically
    • B60T11/08—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting mechanically providing variable leverage
    • 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
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
    • B60T13/22—Brakes applied by springs or weights and released hydraulically
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/02—Conjoint control of vehicle sub-units of different type or different function including control of driveline clutches
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/18—Conjoint control of vehicle sub-units of different type or different function including control of braking systems

Definitions

  • This invention relates generally to a lever assembly and more particularly to a lever assembly having a mechanism to effectively change the magnitude of the required force needed by the operator to overcome an increasing biasing force which is resisting lever movement.
  • Lever assemblies are provided on vehicles and other apparatus to control operation of valves, brakes, release mechanisms, etc. These assemblies normally provide a mechanical advantage so that an operator does not have to apply a large amount of force to actuate a valve or. other components. In most situations, the lever or the component being actuated, is moved against an increasing bias of one or more springs. Consequently, the longer the stroke required for the component being actuated, the greater the amount of force needed to overcome the increasing spring force. These added efforts made by the operator over extended periods of time physically fatigues the operator.
  • Lever arrangements having a cam located thereon have been used to allow actuation -of one valve prior to actuation of a second valve. Howeyer, these arrangements use springs that continually add additional resistance as the lever is being moved. Thus, the increasing spring force of each valve becomes additive as both valves are being actuated.
  • the use of springs with a light force and a low spring rate are not practical because the valve needs a sufficient biasing force to maintain it in a neutral position and the operator needs a "bump" or "feel” to indicate that he has completed modulation of the one valve and ready to start modulation of the other valve with further movement of the lever. Consequently, a light rate spring would not provide the noted requirements. Furthermore, the spring must have sufficient force to move the valving element back to a neutral or initial position without concern of the valve element "sticking" .
  • the present invention is directed to overcoming one or more of the problems as set forth above.
  • a lever assembly has an input shaft and a lever secured to the input shaft being adapted to move a valving element against an increasing biasing force in response
  • OMPI s& IPO ⁇ > to an input force.
  • a cam surface is formed on the lever and defines a profile having a ramp portion.
  • a means is provided for transmitting a force to the cam surface so that the magnitude of the required input force needed to move the lever against the increasing biasing force is controllably varied in response to the position of the lever.
  • the present invention provides a cam-lever arrangement having a biasing force subjected to the cam surface so that a resultant force can be passed through the lever depending on lever position to aid the input force.
  • This arrangement further allows a "bump” or a "feel” to be placed anywhere in the total lever travel to indicate to the operator that a certain functional position has been reached. Furthermore, this arrangement reduces the_ amount of input effort needed so that operator fatigue is reduced.
  • Fig. 1 is a partial schematic and diagrammatic representation of a lever assembly associated with a steering clutch and brake valve and incorporating an embodiment of the present invention
  • Fig. 2 is an enlarged .sectional view of the lever assembly shown in Fig. 1;
  • Fig. 3 is an enlarged sectional view of a portion of the lever assembly shown in Fig. 2;
  • Fig. 4 is a graph illustrating the relationship between the pressure levels in a clutch and brake and the linear travel of the valving elements plus the relationship between the input torque and travel of the valving elements.
  • a clutch and brake valve 10 is shown for use in a control system 12 of a vehicle (not shown) having a pressure-applied, spring-released clutch 14 and a spring-applied, pressure-released brake 16.
  • the control system 12 further includes a pump 18, a reservoir 20 and a lever assembly 22.
  • the clutch and brake valve 10 includes a housing 2.4 having first and second bores 26,28 defined therein.
  • First, second and third chambers 30,32,34 respectively surrounds the first bore 26 at axially spaced locations. Since the second bore 28 is substantially the same as the first bore 26, prime numbers are used to identify corresponding chambers 30',32',34'.
  • An inlet port 36 is defined in the housing 24 and intersects the first chamber 30,30' of each of the fi-rst and second bores 26,28.
  • a drain port 38 is defined in the housing 24 and intersects the third chamber 34,34' of each of the first and second bores 26,28.
  • a first work port 40 is defined in the housing 24 and intersects the second chamber 32 of the first bore 26.
  • a second work port 42 is defined in the housing 24 and intersects the second chamber 32' of the second bore 28.
  • First and second valving elements such as first and second spools 44,46, are respectively slideably disposed in the first and second bores 26,28.
  • the first spool 44 is movable between first, second and third positions while the second spool 46 is movable between first and second positions.
  • First and second springs 48,50 respectively bias the respective first and second spools 44,46 to their first position as shown.
  • each of the spools 44,46 controls the fluid flow to and from the respective clutch 14 and brake 16.
  • a conduit 52 connects the pump 18 with the inlet port 36 and a conduit 53 connects the drain port 38 with the reservoir 20.
  • a relief valve 54 is connected to the conduit 52 and, as is well known in the art, adapted to control the maximum pressure level of the fluid from the pump 18. The pressure-applied, spring-released clutch
  • the spring-applied, pressure-released brake 16 includes an actuator 66 having a pressure chamber 68, a spring chamber 70 and a spring 72 located in the spring chamber 70.
  • a conduit 74 connects the pressure chamber 68 of the brake actuator 66 with the second work port 42 of the vaive 10. * .
  • the lever assembly 22 includes an input shaft 78 mounted in a housing 79 and having a lever 80 extending therefrom.
  • First and second rollers 81,82 are rotatably secured to the lever 80 and adapted to contact the respective first and second spools 44,46 on the ends opposite the respective first and second springs 48,50.
  • a cam surface 84 is located on the lever 80. The cam surface defines a profile 86 having a shoulder 88, sequentially followed by a recess 90, a first step portion 92, a first ramp portion 94, a second step portion 96 and a second ramp portion 98.
  • a means 106 is provided in the lever assembly 22 for transmitting a force to the cam surface 84 so that the magnitude of an input force is controllably varied in response to the position of the lever 80.
  • the force transmitting means 106 includes a spring biasing mechanism 108 secured to the housing 79 and in contact with the cam surface 84.
  • the spring biasing mechanism 108 includes a spring element, such as a leaf spring 110, connected at one end to the housing 79 by any suitable fastening means, such as a bolt 112.
  • first and second bearing members 114,116 are -secured at a spaced apart relationship to the other end of the leaf spring 110.
  • a cylindrical member 118 is rotatably disposed in the first and second bearing members 114,116. Snap rings 120 located on each end of the cylindrical member 118 retains the cylindrical member 118 in the bearing members 114,116 in a well known manner.
  • a phantom line 126 represents the relationship of the pressure in the clutch 14 ' relative to movement of the first spool 44 between its first, second and third positions.
  • a solid line 128 represents the relationship of the pressure in the brake 16 relative to movement of the second spool 46 between its first and second positions.
  • a dashed line 130 represents the relationship of the input torque needed on the input shaft 78 relative to movement of the first and second spools 44,46.
  • lever assembly 22 could be mounted in the housing 24 as opposed to the separate housing 79. Even though the best mode uses a lever 80 that actuates two valve spools 44,46, it is noted that the subject invention is also usable in a system having only one valve spool. Furthermore, the subject lever assembly would be applicable to any lever arrangements that is being moved against an increasing biasing force.
  • pressurized fluid from the pump 18 is directed through the clutch and brake valve 10 to the pressure chambers 58,68 of the respective clutch 14 and brake 16.
  • Pressurized fluid in the pressure chamber 58 applies the clutch 14 while pressurized fluid in the pressure chamber 68 releases the brake.
  • an input force is applied to rotate the input shaft 78.
  • the input force is transferred through the lever 80 to the end of the spool 44 thus moving the spool 44 from the first position, at which the first work port 40 communicates with the inlet port 36 and is blocked from the drain port 38, to the second position, at which the first work port 40 is blocked from the inlet port 36 and open to the drain port 38. Further rotation of the input shaft 78 moves the first spool 44 from the second position to the third position, at which the first work port 40 remains blocked from the inlet port 36 and open to the drain port 38. Between the first and second positions of the first spool 44, the fluid flow to the clutch 14 is variably controlled. By venting the pressurized fluid from the pressure chamber 58 of the clutch 14, the force of the spring 62 releases the clutch 14.
  • the profile of the first ramp portion 94 has a negative slope which results in a force vector that generates a force on the spool 44 that effectively reduces the
  • the cylindrical member 118 Upon adding the extra effort to the input shaft 78, the cylindrical member 118 rolls up the second step portion 96. This rotation of the input shaft 78 initiates movement of the second spool 46 from its first position towards its second position to controllably vent fluid from the pressure chamber 68 and apply the brake 16. As the cylindrical member 118 rolls on the negative slope of the second ramp portion 98 due to rotation of the lever 80, a vector force acts in combination with the input force through the lever 80 to move the spools 44,46 against the combined increasing bias of the springs 48,50. This vector force effectively reduces the operator's effort as indicated above with respect to the first ramp portion 94. Furthermore, the slope of this ramp portion 98 may also be varied to either increase or decrease the operator's effort.
  • the brake 16 is fully applied once the spools 44,46 reaches their end of travel. ⁇ pon release of the input force, the lever 80 is rotated back to the initial position in response to the bias of the springs 48,50 moving the first and second spools 44,46 back to their first positions.
  • the shoulder 88 provides a positive stop so that rotation of the lever 80 is stopped and the cylindrical member 118 stops in the recess 90.
  • the graph in Fig. 4 illustrates one example of a system using the present invention.
  • the relief valve 54 is set to control the maximum pressure of the fluid from the pump 18 at 2800 kPa (406 psi).
  • the maximum spool travel is 20 mm (.787 in.) and the input effort to the input shaft 78 is illustrated as input torque on the input shaft 78.
  • the line 126 illustrates the pressure modulation of the pressure in the clutch 14. As shown, once the spool 44 is moved approximately 8 mm, the clutch 14 is fully released.
  • the line 130 which • represents the input torque on the input shaft 78, illustrates on the left side the effort needed to cause the cylindrical member 118 to be moved from the recess 90.
  • the line 130 illustrates the effort or "bump" needed to move the cylindrical member 118 relative to the second step portion 96.
  • the line 128 illustrates the pressure modulation of the pressure in the brake 16.
  • the two slopes in the line 130 can be varied by changing the profile of the respective first and second ramp portions 94,98.
  • the height of the steps in the line 130 can be changed by changing the height of the respective first and second steps 92,94 or by changing the biasing force of the leaf spring 110.

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanically-Actuated Valves (AREA)

Abstract

Des valves de commande ayant un élément de soupape qui se déplace par rapport à une force oblique croissante pour commander le courant de liquide allant vers un mécanisme de commande ou partant de celui-ci sont utiles dans les véhicules de chantiers de construction pour commander un embrayage et/ou un frein. La force oblique croissante des ressorts augmente la fatigue de l'opérateur. Certains systèmes utilisent des surfaces sensibles à la pression sur le boisseau de clapet pour compenser les forces ajoutées des ressorts, mais ces systèmes nécessitent une source de pression que l'on puisse faire varier par rapport à la position du boisseau de clapet. Le présent ensemble levier (22) comporte un arbre d'entrée (78) possédant un levier (80) fixé sur cet arbre, et pourvu d'une surface à came (84) définie sur le levier (80), et un mécanisme de transmission de force (106) adapté pour pouvoir transmettre une force variable au boisseau de clapet (44/46) en réaction à la position du levier (80). Le mécanisme de transmission de force (106) en combinaison avec le profil (86) de la surface à came (84) réduit efficacement la force d'entrée nécessaire pour déplacer le boisseau de clapet (44/46) en s'opposant au mouvement de résistance du boisseau de clapet (44/46) à une force oblique croissante, réduisant ainsi la fatigue de l'opérateur.
PCT/US1984/001703 1984-08-13 1984-11-13 Ensemble levier avec modification de la force requise Ceased WO1986001162A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US63987384A 1984-08-13 1984-08-13
US639873 1996-04-26

Publications (1)

Publication Number Publication Date
WO1986001162A1 true WO1986001162A1 (fr) 1986-02-27

Family

ID=24565926

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1984/001703 Ceased WO1986001162A1 (fr) 1984-08-13 1984-11-13 Ensemble levier avec modification de la force requise

Country Status (2)

Country Link
FR (1) FR2568832A1 (fr)
WO (1) WO1986001162A1 (fr)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2380619A (en) * 1941-07-30 1945-07-31 Ind Brownhoist Corp Steering mechanism for tractor cranes
US2725890A (en) * 1950-03-22 1955-12-06 Borg Warner Hydraulic power control system
US3853210A (en) * 1971-11-16 1974-12-10 Aisin Seiki Transmission control system for vehicles
US3929245A (en) * 1973-11-07 1975-12-30 Komatsu Mfg Co Ltd Device for setting the inclination of the bucket in a bulldozer
US4103559A (en) * 1977-03-09 1978-08-01 Caterpillar Tractor Co. Detented manual actuator for a multifunction system
US4215771A (en) * 1978-03-08 1980-08-05 J. I. Case Company Single lever control system
US4246992A (en) * 1976-05-21 1981-01-27 Caterpillar Tractor Co. Vehicle steering brake and clutch control
US4275613A (en) * 1978-04-20 1981-06-30 Daimler-Benz Aktiengesellschaft Detent mechanism for the different positions of a change-speed transmission, especially for motor vehicles

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2380619A (en) * 1941-07-30 1945-07-31 Ind Brownhoist Corp Steering mechanism for tractor cranes
US2725890A (en) * 1950-03-22 1955-12-06 Borg Warner Hydraulic power control system
US3853210A (en) * 1971-11-16 1974-12-10 Aisin Seiki Transmission control system for vehicles
US3929245A (en) * 1973-11-07 1975-12-30 Komatsu Mfg Co Ltd Device for setting the inclination of the bucket in a bulldozer
US4246992A (en) * 1976-05-21 1981-01-27 Caterpillar Tractor Co. Vehicle steering brake and clutch control
US4103559A (en) * 1977-03-09 1978-08-01 Caterpillar Tractor Co. Detented manual actuator for a multifunction system
US4215771A (en) * 1978-03-08 1980-08-05 J. I. Case Company Single lever control system
US4275613A (en) * 1978-04-20 1981-06-30 Daimler-Benz Aktiengesellschaft Detent mechanism for the different positions of a change-speed transmission, especially for motor vehicles

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
STRASSER F.: "15 Ideas for Cam mechanisms", PRODUCT ENGINEERING, 3 August 1959 (1959-08-03), pages 56 - 57 *

Also Published As

Publication number Publication date
FR2568832A1 (fr) 1986-02-14

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