EP1224101A1 - Dispositif de freins destine a une machine de construction - Google Patents

Dispositif de freins destine a une machine de construction

Info

Publication number
EP1224101A1
EP1224101A1 EP00973307A EP00973307A EP1224101A1 EP 1224101 A1 EP1224101 A1 EP 1224101A1 EP 00973307 A EP00973307 A EP 00973307A EP 00973307 A EP00973307 A EP 00973307A EP 1224101 A1 EP1224101 A1 EP 1224101A1
Authority
EP
European Patent Office
Prior art keywords
brake
hydraulic oil
valve
circuit
pressure
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.)
Withdrawn
Application number
EP00973307A
Other languages
German (de)
English (en)
Inventor
Bo Vigholm
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.)
Volvo Wheel Loaders AB
Original Assignee
Volvo Wheel Loaders AB
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 Volvo Wheel Loaders AB filed Critical Volvo Wheel Loaders AB
Publication of EP1224101A1 publication Critical patent/EP1224101A1/fr
Withdrawn legal-status Critical Current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
    • 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
    • B60T13/14—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 using accumulators or reservoirs fed by pumps
    • B60T13/141—Systems with distributor valve
    • 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
    • B60T13/66—Electrical control in fluid-pressure brake systems
    • B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
    • B60T13/686—Electrical control in fluid-pressure brake systems by electrically-controlled valves in hydraulic systems or parts thereof
    • 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
    • B60T8/26—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force characterised by producing differential braking between front and rear wheels

Definitions

  • the present invention relates to a brake device for a construction machine, comprising a first brake circuit, which is coupled to a first brake member on a first wheel axle of the machine, a second brake circuit, which is coupled to a second brake member on a second wheel axle of the machine, the said first and second brake circuits being independent of one another, a pressure source for hydraulic oil, which is coupled to the first and second brake circuit, and a brake valve, which is coupled to the first and second brake circuit, the brake valve being designed to control the hydraulic oil from the pressure source to the brake members on the wheel axles .
  • a construction machine such as a wheeled loader or a dumper truck, must be equipped with brakes that are suited to the varying characteristics of the machine.
  • the brake systems hitherto fitted on construction machines comprise two or more independent brake circuits, which are controlled by a brake valve.
  • the brake valve is coupled to the brake pedal, which opens the valve when a force is applied by the driver, so that hydraulic oil under pressure flows to brake members, which are arranged on machine wheel axles or wheels.
  • the brake members comprise a piston, which is moved under the pressure of the hydraulic oil and presses a brake lining 7 against a brake disc.
  • the pressure on the brake piston 5 ceases and the brake lining 7 is moved into an initial position by means of return springs.
  • the jerking and the noise are experienced by the driver of the machine as irritations.
  • gentle braking the force on the brake pedal must be slight. If the machine is travelling on an uneven surface, so that the machine jumps and shakes, it becomes difficult for the driver to control the brake device by means of the brake pedal in order to achieve gentle braking. The retardation of the machine will then vary, so that the driver perceives the brake device as difficult to control.
  • the brake application time In order to achieve good controllability of the brake device, the brake application time must be as short as possible and the excess pressure surge as small as possible. A short brake application time is achieved by means of a large flow of hydraulic oil through the brake valve, but the greater the flow of hydraulic oil, the greater the excess pressure surge becomes .
  • An object of the present invention is to produce a brake device, which is adapted to the various operating conditions of a construction machine, so that machine jerking and noise are avoided when braking the machine.
  • Another object of the invention is to produce a brake device that exhibits little sensitivity in gentle braking .
  • a brake device of the type specified in the introductory part in which a limiting element arranged in the first or second brake circuit limits the pressure and/or flow of the hydraulic oil when the brake valve is controlling the hydraulic oil from the pressure source to the brake members on the wheel axles.
  • the limiting element helps to reduce the braking action on the one wheel axle at the commencement of the braking sequence, which thereby reduces the sensitivity of the brake device.
  • the driver depresses the brake pedal gently in order to brake gently, only a small flow of hydraulic oil, if any, will occur in the brake circuit that is fitted with the limiting element, while a large flow of hydraulic oil will flow in the brake circuit that is not fitted with a limiting element.
  • the pressure applied to the brake member on the wheel axle that had reduced braking action from the outset will increase the braking action on that wheel axle.
  • emergency-stop braking for example, all wheel axles of the vehicle will be braked immediately when the driver presses the brake pedal .
  • Fig. 1 shows the hydraulic pressure as a function of the time taken to activate a known brake device
  • Fig. 2 shows a first embodiment of a brake device according to the present invention
  • Fig. 3 shows a brake valve for the brake device according to the present invention
  • Fig. 4 shows a second embodiment of a brake device according to the present invention
  • Fig. 5 shows a third embodiment of a brake device according to the present invention
  • Fig. 6 shows a fourth embodiment of a brake device according to the present invention.
  • Figure 1 contains a graph showing how the hydraulic pressure varies when a known brake device is activated.
  • the horizontal axis gives the time T and the vertical axis gives the pressure P.
  • it takes a certain time tl to move a brake piston from an initial position to a position assumed by the brake piston when a brake lining, against which the brake piston presses, is bearing against a brake disc.
  • the pressurization of the hydraulic oil against the brake piston commences, which leads to a powerful excess pressure surge in the form of a pressure pulse in the hydraulic oil. This pressurization takes place over a period of time t2.
  • Figure 2 shows a first embodiment of a brake device
  • the brake device 1 comprises a first brake circuit 2, which is coupled to a first brake member 4 on a first wheel axle 6 of a construction machine.
  • the brake member 4 comprises a brake piston 5 fitted to each wheel, which piston by way of one or more brake linings 7 interacts with a brake disc (not shown) connected to the wheel axle 6.
  • the brake device 1 also comprises a second brake circuit 8, which is coupled to a second brake member 10 on a second wheel axle 12 of the machine. After application of the brake device the first and second brake circuits 2, 8 are independent of one another, which means that the pressure in one circuit 2, 8 does not affect the hydraulic oil pressure in the other circuit 2, 8. If one circuit 2, 8 fails, the construction machine can still be braked by means of the other circuit 2, 8.
  • a pressure source 14 for hydraulic oil is coupled to the first and second brake circuit 2, 8.
  • the pressure source 14 may take the form, for example, of a hydraulic pump and/or one or more hydraulic accumulators (not shown) .
  • a brake valve 16 is coupled to the first and second brake circuit 2, 8, which brake valve 16 is designed to control the hydraulic oil from the pressure source 14 to the brake members 4, 10 on the wheel axles 6, 12.
  • a limiting element in the form of a sequence valve 18 is arranged in the second brake circuit 8.
  • the sequence valve 18 When the brake valve 16 controls the hydraulic oil from the pressure source 14 to the brake members 4, 10 on the wheel axles 6, 12, the sequence valve 18 will limit the hydraulic oil flow to the second brake member 10 if the pressure of the hydraulic oil falls below a predetermined pressure. This limiting may mean that little hydraulic oil, if any, flows through the sequence valve 18.
  • the sequence valve 18 opens when the hydraulic oil pressure reaches a predetermined pressure, so that a large hydraulic oil flow through the sequence valve 18 occurs.
  • the function of the sequence valve 18 can thus be likened to the function of a pressure-relief valve.
  • a first bypass line 22 is connected over the sequence valve 18, so that hydraulic oil is allowed to bypass the sequence valve 18.
  • a non- return valve 24 is arranged in the first bypass line 22, so that hydraulic oil is prevented from flowing through the first bypass line 22 in the direction towards the second brake member 10.
  • the brake valve 16 comprises a first and second valve 26, 28, which are acted upon by a brake pedal 30.
  • the first and second slide valves 26, 28 are opened, so that hydraulic oil flows from the pressure source 14 towards the first and second brake members 4, 10. It is preferably the pressure in the first brake circuit 2 that influences the opening of the second slide valve 28, which is indicated by a duct 29 between the first brake circuit 2 and the second slide valve 28.
  • first and second slide valves 26, 28 together with the sequence valve 18 and the first bypass line 22 with the non-return valve 24 may be replaced by a brake valve 16', as shown in figure 3.
  • the said brake valve 16' comprises a first slide 32, which controls the flow of hydraulic oil in the first brake circuit 2, and a second slide 34, which controls the flow of hydraulic oil in the second brake circuit 8.
  • the first slide 32 is arranged so as to control the second slide 34, so that the second slide 34 opens the second brake circuit 8 when the pressure in the first brake circuit 2 has reached a predetermined pressure.
  • the said predetermined pressure is determined by the spring force of a first spring 36 of the brake valve 16' .
  • the first slide 32 is connected to the brake pedal 30 and when the brake pedal 30 is depressed, the first slide 32 will be displaced in the brake valve 16', so that the first brake circuit 2 is opened.
  • a second spring 38 arranged between the first and second slide 32, 34, ensures that the second slide 34 is not displaced by the first slide 32 from the outset.
  • a second branch line 35 in the second circuit 8 carries hydraulic oil to the end of the second slide 34, which faces the first spring 36.
  • the second slide 34 will close the second circuit 8.
  • the pressure in the second circuit 8 will thereby become lower than the pressure in the first circuit 2.
  • the difference between the pressure in the first and second circuit 2, 8 depends upon the magnitude of the spring force of the first spring 36.
  • the first spring 36 will thereby function as a limiting element. If the brake pedal 30 is only depressed a short way, in order to undertake gentle braking, only the first wheel axle 6 will be braked.
  • both of the brake circuits 2, 8 are opened, which means that both of the wheel axles 6, 12 are braked. If one of the circuits 2, 8 should fail and hydraulic pressure in one of the circuits 2, 8 be absent when the brake device 1 is applied, the brake pedal 30 can be depressed to such a degree that the second spring 38 is compressed, which means that the second slide 34 will also be displaced, so that the second brake circuit 8 is opened.
  • Figure 4 shows a second embodiment of the invention.
  • a second bypass line 40 is arranged over the sequence valve 18.
  • a restrictor valve 42 which means that a limited flow of hydraulic oil can always bypass the sequence valve 18, is arranged in the second bypass line 40.
  • a third embodiment which is shown in figure 5
  • the restrictor valve 42' here constitutes a limiting element. In this way brake shock is prevented in gentle braking of the machine.
  • a brake device 1 with two brake circuits 2 , 8 has been descried above. It is possible, however, to design the brake device 1 with three or more brake circuits. It is also possible to arrange the limiting element 18, 42' in the first brake circuit 2 rather than the second brake circuit 8.
  • the first wheel axle 6 may be a front axle and the second wheel axle 12 may be a rear axle of the machine, or vice versa.

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Regulating Braking Force (AREA)
  • Braking Systems And Boosters (AREA)
  • Braking Arrangements (AREA)
  • Hydraulic Control Valves For Brake Systems (AREA)
  • Valves And Accessory Devices For Braking Systems (AREA)

Abstract

L'invention concerne un dispositif de freins (1) destiné à une machine de construction, qui comporte un premier circuit de freins (2) couplé à un premier élément de freins (4) situé sur un premier essieu de roue (6) de la machine, un second circuit de freins (8) couplé à un second élément de freins (10) situé sur un second essieu de roue (12) de la machine, le premier et le second circuit de freins (2, 8) étant indépendants l'un de l'autre, une source de pression (14) d'huile hydraulique, couplée au premier et au second circuit de freins (2, 8) et un clapet de frein (16, 16') couplé au premier et au second circuit de freins (2, 8), ce clapet étant conçu pour commander l'huile hydraulique de la source de pression (14) aux éléments de freins (4, 10) sur les essieux de roue (6, 12). Le premier ou le second circuit de freins (2, 8) comprend des éléments de limitation (18, 42'), qui limitent la pression et/ou le débit d'huile hydraulique lorsque le clapet de frein (16, 16') commande l'huile hydraulique de la source de pression (14) aux éléments de freins (4, 10) situés sur les essieux de roue (6, 12).
EP00973307A 1999-10-26 2000-10-18 Dispositif de freins destine a une machine de construction Withdrawn EP1224101A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9903856A SE516450C2 (sv) 1999-10-26 1999-10-26 Bromsanordning för en entreprenadmaskin samt förfarande för bromsning av entreprenadmaskinen
SE9903856 1999-10-26
PCT/SE2000/002014 WO2001030625A1 (fr) 1999-10-26 2000-10-18 Dispositif de freins destiné à une machine de construction

Publications (1)

Publication Number Publication Date
EP1224101A1 true EP1224101A1 (fr) 2002-07-24

Family

ID=20417489

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00973307A Withdrawn EP1224101A1 (fr) 1999-10-26 2000-10-18 Dispositif de freins destine a une machine de construction

Country Status (5)

Country Link
EP (1) EP1224101A1 (fr)
JP (1) JP2003512252A (fr)
AU (1) AU1183301A (fr)
SE (1) SE516450C2 (fr)
WO (1) WO2001030625A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10217631A1 (de) 2002-04-19 2004-03-04 Bosch Rexroth Ag Bremssystem
KR20130129992A (ko) * 2010-12-28 2013-11-29 볼보 컨스트럭션 이큅먼트 에이비 휠 타입 건설기계의 브레이크 제어장치
IT201800007831A1 (it) * 2018-08-03 2020-02-03 Cnh Ind Italia Spa Valvola di potenza per freni

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2907425A1 (de) * 1979-02-26 1981-02-12 Wabco Fahrzeugbremsen Gmbh Automatisch-lastabhaengige bremskraftregeleinrichtung
DE4124241A1 (de) * 1991-07-22 1993-01-28 Bosch Gmbh Robert Hydraulische bremsanlage, insbesondere fuer kraftfahrzeuge
DE4320390A1 (de) * 1993-06-19 1994-12-22 Teves Gmbh Alfred Blockiergeschützte hydraulische Bremsanlage
DE19624548B4 (de) * 1995-06-28 2004-02-05 Volkswagen Ag Bremsanlage für ein Kraftfahrzeug
DE19546056A1 (de) * 1995-12-09 1997-06-12 Teves Gmbh Alfred Hydraulische Bremsanlage mit Hochdruckquelle und pedalbetätigtem Dosierventil

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0130625A1 *

Also Published As

Publication number Publication date
SE9903856L (sv) 2001-04-27
JP2003512252A (ja) 2003-04-02
SE516450C2 (sv) 2002-01-15
WO2001030625A1 (fr) 2001-05-03
AU1183301A (en) 2001-05-08
SE9903856D0 (sv) 1999-10-26

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