GB2277064A - Lifting appliance for a lifting axle of a truck - Google Patents

Lifting appliance for a lifting axle of a truck Download PDF

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Publication number
GB2277064A
GB2277064A GB9406148A GB9406148A GB2277064A GB 2277064 A GB2277064 A GB 2277064A GB 9406148 A GB9406148 A GB 9406148A GB 9406148 A GB9406148 A GB 9406148A GB 2277064 A GB2277064 A GB 2277064A
Authority
GB
United Kingdom
Prior art keywords
lifting
hydraulic
axle
pneumatic
lifting axle
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.)
Granted
Application number
GB9406148A
Other versions
GB9406148D0 (en
GB2277064B (en
Inventor
Rolf Koster
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.)
Daimler Benz AG
Original Assignee
Daimler Benz AG
Mercedes Benz AG
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 Daimler Benz AG, Mercedes Benz AG filed Critical Daimler Benz AG
Publication of GB9406148D0 publication Critical patent/GB9406148D0/en
Publication of GB2277064A publication Critical patent/GB2277064A/en
Application granted granted Critical
Publication of GB2277064B publication Critical patent/GB2277064B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
    • B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
    • B60G17/0152—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the action on a particular type of suspension unit
    • B60G17/0155—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the action on a particular type of suspension unit pneumatic unit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G11/00—Resilient suspensions characterised by arrangement, location or kind of springs
    • B60G11/26—Resilient suspensions characterised by arrangement, location or kind of springs having fluid springs only, e.g. hydropneumatic springs
    • B60G11/30—Resilient suspensions characterised by arrangement, location or kind of springs having fluid springs only, e.g. hydropneumatic springs having pressure fluid accumulator therefor, e.g. accumulator arranged in vehicle frame
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D61/00—Motor vehicles or trailers, characterised by the arrangement or number of wheels, not otherwise provided for, e.g. four wheels in diamond pattern
    • B62D61/12—Motor vehicles or trailers, characterised by the arrangement or number of wheels, not otherwise provided for, e.g. four wheels in diamond pattern with variable number of ground engaging wheels, e.g. with some wheels arranged higher than others, or with retractable wheels

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Vehicle Body Suspensions (AREA)
  • Forklifts And Lifting Vehicles (AREA)

Description

2277064 1 Lifting appliance for a lifting axle of a truck The invention
relates to a lifting appliance for a lifting axle of a truck having a pneumatic pressure system with at least one hydraulic displacement unit f or raising the lifting axle.
The arrangement of a lif ting axle which can be raised from the road surface is expedient where trucks frequently travel with widely varying load. The lifting axle, together with a driving axle or main axle whose wheels continually run on the road surface, generally forms a double-axle unit, the lifting axle being controlled in such a way that in the case of a low vehicle load, only the wheels of the driving axle or main axle are in contact with the ground and the lifting axle is in its raised condition. At high load, on the other hand, the wheels of the lifting axle are lowered onto the road surface so that the vehicle load is taken partially by the driving or main axle and partially by the lif ting axle. If necessary, the ground pressure of the lifting axle can be temporarily reduced in the case of a heavy vehicle load in order, for example, to load the driving axle more strongly and correspondingly increase the traction of the driving wheels.
This controllable axle load distribution can then be ef f ected in a particularly simple manner if the main or driving axle and the adjacent lifting axle are pneumatically suspended. At the same time, the possibility then exists of controlling the ground clearance of the vehicle in order, for example, to be able to drive under or raise the semitrailer of a semi-trailer motor vehicle when coupling or decoupling.
A pneumatic-suspension vehicle is known from DE-C 28 11 874, in which the pneumatic suspension units of the lifting axle are ventilated by a control valve arrangement whenever the control valve arrangement switches over into a condition in which compressed air is admitted to a pneumatic lifting unit of the lifting axle.
2 If necessary, the lifting unit can also operate hydraulically and be configured with its own hydraulic circuit.
Furthermore, a vehicle with a mechanical suspension and a lifting axle is shown in DE-C 28 11 874, the abutments of the mechanical suspension elements - leaf springs in the example represented - being adjusted by means of a hydraulic or pneumatic displacement unit in order to effect the lifting motion of the lifting axle.
From DE-A 22 10 070, it is known art to equip a pneumatic-suspension truck with shock absorbers at the lifting axle. These shock absorbers have an additional pneumatic chamber. Pneumatic pressure can be admitted to this pneumatic chamber and this pressure then attempts to push the piston of the respective shock absorber into the associated cylinder so that the lifting axle is correspondingly adjusted in the upward direction.
EP-A 03 92 380 shows a further vehicle with a mechanical suspension and a lifting axle raised by means of a hydraulic displacement unit, which uses a lever mechanism to adjust the position of leaf-spring elements relative to the vehicle superstructure.
From German Utility Model 92 05 435, it is known art to configure hydraulic shock absorbers in such a way that they can also be employed as the hydraulic lifting units of a lifting axle. These shock absorbers are configured in the conventional manner as piston/cylinder units in which, within the cylinder, the piston separates two hydraulic chambers which normally communicate with one another via a throttle section, one of the hydraulic chambers being connected to a pneumatic reservoir. The two chambers can be separated from one another in order to raise the lifting axle. Additional hydraulic medium is then introduced into the chamber which is not connected to the pneumatic reservoir. The lifting axle is raised during the associated enforced adjustment of the shock absorber.
From EP-A 02 99 849, it is known art to arrange a gas 3 reservoir spring as the lif ting unit. This gas reservoir spring continually attempts to raise the lifting axle, which in this case is suspended pneumatically. If the air spring bellows of the lifting axle are now ventilated, the lifting axle is raised by the gas reservoir spring. The lifting axle and its wheels can then be lowered onto the road surface again by subjecting the gas spring bellows of the lifting axle to pneumatic pressure. The air suspension of the lifting axle must then, however, operate continually against the return force of the gas reservoir spring.
Hydropneumatic driving systems are generally known from the journal "antriebstechnik" 26 (1987) No. 10, Pages 30 to 34. In this system, the intention is to combine the advantages of compressed air technology - high operational speed because of rapid energy availability - with those of hydraulic systems (good control over the hydraulic flow). In such systems, pressure medium transducers are inserted at interfaces between the hydraulic and pneumatic systems in order to convert pneumatic pressure into hydraulic pressure. If necessary, these pressure medium transducers can be configured as pressure intensifiers which are used to convert the compressed air operating pressure into an oil pressure which is a multiple of the air pressure. Such hydropneumatic drives are mainly used for automated, process-controlled manufacturing plant.
DE-A 41 27 801 also shows a hydropneumatic suspension system for motor vehicles with a lifting axle which can be raised hydraulically.
The present invention seeks to obtain, in a lifting appliance of the type mentioned at the beginning, a particularly compact design with low design requirements in the region of the lifting axle.
According to the present invention there is provided a lifting appliance for a lifting axle of a truck having a pneumatic pressure system with at least one hydraulic displacement unit for raising the lifting axle, wherein the hydraulic displacement unit interacts, as a receiver, with 4 a remotely arranged transmitter, which likewise comprises a hydraulic displacement unit is adapted to be actuated by means of a pneumatic actuating unit, the displacement unit forming the transmitter and the.actuating unit form a pneumatic/hydraulic pressure intensifier which generates hydraulic pressures which are high in comparison with the pneumatic pressure.
The invention takes account of the fact that there is frequently extraordinarily little installation space available in the region of the lifting axle. This applies particularly to semi-trailer motor vehicles with pneumatic suspension for a driving axle and an adjacent lifting axle beneath the semi-trailer coupling. The installation space available is then additionally limited by the fact that the air suspension also has to permit the ground clearance of the semi-trailer motor vehicle to be changed when coupling and decoupling a semi-trailer, i.e. it is necessary to arrange air suspension units with particularly large lift displacements.
In the invention, the restricted relationships at the lifting axle are taken into account because it is only necessary to arrange one hydraulic displacement unit there for raising the lifting axle and, because of the high hydraulic pressures, this hydraulic displacement unit can be very small.
Otherwise, the invention is based on the knowledge that in vehicles which already have a pneumatic pressure system in any case, for example for a pneumatic suspension, the lifting appliance for the lifting axle should also be pneumatically driven in order to permit desirable design simplicity overall. Because a pneumatic actuating unit actuates a hydraulic transmitter which has a positive hydraulic connection to the hydraulic displacement unit used for raising the lifting axle, the possibility is created of arranging the relatively large-space pneumatic actuating unit remote from the lifting axle wherever there is sufficient space available on the vehicle. Because the Y' i hydraulic transmitter/receiver arrangement offers every possible f reedom in this respect, the use of f ree spaces available on the vehicle is readily possible and, furthermorO-, an arrangement which is easily accessible for inspection purposes can also be achieved.
The displacement units used for raising the lifting axle can be conf igured, in a manner known per se, as hydraulic shock absorbers so that they thus undertake a double function - shock absorbing and adjustment of the lifting axle.
The displacement units can, instead, also be integrated in the shock absorbers.
A preferred embodiment of the invention is explained in more detail below using the drawing. The single f igure shows a circuit diagram type of representation of the lifting appliance according to the invention.
A pneumatic pressure source 1 which, by means of a pneumatic network not shown in any more detail, also supplies the pneumatic suspension of a truck (not shown), is connected by means of a control valve 2 to a pneumatic actuating unit 3, which is represented diagrammatically as a pneumatic bellows. The control valve 2 can take up two positions. In one position - the one shown - the pneumatic pressure source subjects the pneumatic actuating unit 3 to pneumatic pressure so that the pneumatic bellows forming the actuating unit 3 attempts to expand. In the other position of the control valve 2, the pneumatic actuating unit 3 is shut off from the pneumatic pressure source 1 and is connected to a ventilation opening 4 so that the actuating unit 3 is relieved of pressure.
The pneumatic actuating unit 3 has a positive connection to a first hydraulic displacement unit 5 which in turn has positive hydraulic connection via a hydraulic conduit 6 to further hydraulic displacement unit 7 in such a way that hydraulic medium expelled from the displacement unit 5 is forced into the displacement unit 7 and hydraulic medium expelled from the displacement unit 7 is accepted by the 6 displacement unit 5. The displacement device, configured as a piston, of the displacement unit 5 correspondingly executes an inward stroke when the piston of the displacement unit 7 executes an outward stroke. An inward stroke of the piston of the displacement unit 7 is correspondingly associated with an outward stroke of the piston of the displacement unit 5.
The displacement unit 7 is arranged in such a way between the chassis of a vehicle and its lifting axle (not shown) that the lifting axle is raised when the piston of the diAsplacement unit 7 is pushed out. This outward stroke takes place as soon as the actuating unit 3 is expanded by the supply of pneumatic pressure medium and the piston of the displacement unit 5 is displaced in the direction of an inwards motion.
If the actuating unit 3 is ventilated, the lifting axle can sink under its own weight so that the piston of the displacement unit 7 moves in the inward direction and the piston of the displacement unit 5 is pushed out so that the ventilated actuating unit 3 is compressed.
The pneumatic springs (not shown) of the lifting axle are simultaneously subjected to pneumatic pressure so that the lifting axle can accept a specified proportion of the vehicle load. These pneumatic spring elements are automatically ventilated when the lifting axle is raised.
The displacement units 5 and 7 interact as a hydraulic transmitter and a hydraulic receiver which can be arranged remote from one another so that the pneumatic actuating unit 3 and the hydraulic displacement unit 5 can, in principle, be accommodated at arbitrary free spaces on the vehicle. Only the displacement unit 7 needs to be arranged in the region of the lifting axle.
If necessary, two displacement units 7 can also be arranged in parallel with one another and can be configured as shock absorbers of the lifting axle so that they can undertake, on the one hand, the task of lift adjustment of the lifting axle and, on the other, the shock absorbing of T 4 1 7 this lifting axle.
The control valve 2 is controlled by means of an electronic control circuit 8 and electromagnetic actuating elements 9 controlled by it. The control circuit 8 can also undertake the closed-loop control of the pneumatic suspension of the vehicle and the air supply to and ventilation of the pneumatic suspension units of the lifting axle when the lifting axle is being raised and lowered.
8

Claims (3)

  1. Claims
    A lifting appliance for a lifting axle of a truck having a pneumatic pressure system with at least one hydraulic displacement unit for raising the lifting axle, wherein the hydraulic displacement unit interacts, as a receiver, with a remotely arranged transmitter, which likewise comprises a hydraulic displacement unit is adapted to be actuated by means of a pneumatic actuating unit, the displacement unit forming the transmitter and the actuating unit form a pneumatic/hydraulic pressure intensifier which generates hydraulic pressures which are high in comparison with the pneumatic pressure.
  2. 2. A lifting appliance according to Claim 1, wherein said displacement units used for raising the lifting axle are configured as hydraulic shock absorbers of the lifting axle or are integrated in the latter.
  3. 3. A lifting appliance for a lifting axle of a truck, substantially as described herein with reference to and as illustrated in the accompanying drawings.
    Ok 1
GB9406148A 1993-04-06 1994-03-29 Lifting appliance for a lifting axle of a truck Expired - Fee Related GB2277064B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE4311243A DE4311243C2 (en) 1993-04-06 1993-04-06 Lifting device for a lifting axle of a truck

Publications (3)

Publication Number Publication Date
GB9406148D0 GB9406148D0 (en) 1994-05-18
GB2277064A true GB2277064A (en) 1994-10-19
GB2277064B GB2277064B (en) 1996-01-17

Family

ID=6484847

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9406148A Expired - Fee Related GB2277064B (en) 1993-04-06 1994-03-29 Lifting appliance for a lifting axle of a truck

Country Status (5)

Country Link
DE (1) DE4311243C2 (en)
FR (1) FR2703649B1 (en)
GB (1) GB2277064B (en)
IT (1) IT1272971B (en)
SE (1) SE506148C2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014137277A1 (en) 2013-03-07 2014-09-12 Vm Trailer Ab Axle lift for a vehicle

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE20120533U1 (en) * 2001-12-19 2002-08-08 Goldschmitt Techmobil Gmbh Hydropneumatic spring
DE10241490B4 (en) * 2002-09-07 2004-07-22 Contitech Luftfedersysteme Gmbh Motor vehicle air suspension system with damper

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4065143A (en) * 1975-04-14 1977-12-27 Kabushiki Kaisha Komatsu Seisakusho Fluid suspension system
EP0529320A1 (en) * 1991-08-22 1993-03-03 HEMSCHEIDT FAHRWERKTECHNIK GmbH & Co. Hydropneumatic spring system for a vehicle's lift axle

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2210070A1 (en) * 1972-03-02 1973-09-06 Kloeckner Humboldt Deutz Ag AIR-SUSPENDED THREE-AXLE VEHICLE WITH ONE TOWING AXLE
DE2811874C2 (en) * 1978-03-18 1981-09-24 Klöckner-Humboldt-Deutz AG, 5000 Köln Automatic control device for the lifting device of a liftable wheel axle of a double axle unit
JPS59137206A (en) * 1983-01-24 1984-08-07 Nissan Motor Co Ltd Suspension device
AT391838B (en) * 1987-07-10 1990-12-10 Steyr Daimler Puch Ag MULTI-AXLE COMMERCIAL VEHICLE
DE4009576A1 (en) * 1989-04-08 1990-10-11 Iveco Magirus DEVICE FOR LIFTING A TOW OR TRAILER AXLE OF DOUBLE AXLE AGGREGATES IN COMMERCIAL VEHICLES
DE9205435U1 (en) * 1992-04-21 1992-06-25 Fichtel & Sachs Ag, 8720 Schweinfurt, De

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4065143A (en) * 1975-04-14 1977-12-27 Kabushiki Kaisha Komatsu Seisakusho Fluid suspension system
EP0529320A1 (en) * 1991-08-22 1993-03-03 HEMSCHEIDT FAHRWERKTECHNIK GmbH & Co. Hydropneumatic spring system for a vehicle's lift axle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014137277A1 (en) 2013-03-07 2014-09-12 Vm Trailer Ab Axle lift for a vehicle

Also Published As

Publication number Publication date
FR2703649B1 (en) 1997-04-18
SE9401082D0 (en) 1994-03-30
SE9401082L (en) 1994-10-07
GB9406148D0 (en) 1994-05-18
SE506148C2 (en) 1997-11-17
IT1272971B (en) 1997-07-01
GB2277064B (en) 1996-01-17
DE4311243C2 (en) 1995-12-07
DE4311243A1 (en) 1994-10-13
ITRM940190A0 (en) 1994-04-01
ITRM940190A1 (en) 1995-10-01
FR2703649A1 (en) 1994-10-14

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20020329