GB2168015A

GB2168015A - Transmission arrangement of service vehicle

Info

Publication number: GB2168015A
Application number: GB08518665A
Authority: GB
Inventors: Walter Hawelka; Hermann Staudinger
Original assignee: Konrad Rosenbauer KG
Current assignee: Konrad Rosenbauer KG
Priority date: 1984-12-06
Filing date: 1985-07-24
Publication date: 1986-06-11
Also published as: ATA387084A; GB8518665D0; DE3527150A1; FR2574350B1; AT394979B; IT1184825B; NL8502952A; CN85104630A; CN1005473B; ZA855616B; FR2574350A1; GB2168015B; CH668042A5; IT8521946A0; BE903784A

Abstract

A fire service vehicle has a chassis frame 2 and a driving engine 30 which is transmissively coupled through a transmission module 15 to an extinguisher fluid pump 13 and front and rear axles 8, 9, the engine 30 being between a stern of the vehicle and a section situated between the driving axes 8, 9. The auxiliary fluid pump 13 is installed in the region of the front driving axle 8. Advantageously, the auxiliary pump 13 is mounted on an intermediate frame displaceably mounted on the chassis frame 2 for displacement forwardly to an operational position outside the vehicle profile. The transmission module 15 includes a change-speed gearbox. In alternative embodiments, the vehicle may be an elevator vehicle or a public utility vehicle, and the pump 13 may be replaced by an electric generator or hydrostatic pump. <IMAGE>

Description

SPECIFICATION Service vehicle and transmission arrangement The invention relates to a drive arrangement for a service vehicle, particularly but not exclusively for a fire service vehicle, comprising a driving engine, an intermediate transmission and a power-take-off which is transmissively coupled to an auxiliary unit, e.g. an extinguisher fluid pump.

Fire service vehicles which are also constructed for operation on airfields, and comprise different drive layouts, have previously been disclosed by the applicants in which a distributor transmission, through which an extinguisher fluid pump and an automatic gearbox for the propulsive drive are supplied with power, was flange-coupled direct to the driving engine. In such arrangement it was possible for an automatic gearbox having a PTO (power-take-off) operating an extinguisher fluid pump to be flange-coupled direct to the driving engine, and also for a main output drive to lead to the axle drives via an intermediate gearbox.A fire service vehicle of the applicant's is thus already known, in which the propulsive drive is situated in the stern section of the fire service vehicle, the converter and distributor transmission combined into a driving transmission unit being situated generally centrally between the two axles, and the fire extinguisher pump acted upon by the PTO being likewise installed on the chassis frame between the two axles.

A chassis frame has been proposed for a fire service vehicle, according to the research report of the Federal Minister for Research and Technology of the Federal Republic of Germany regarding optimised life-saving and fire-fighting with integrated technical assistance of July 1978, also referred to as an "Orbit" study, in which the driving engine for a 4 x 4 vehicle (two axles having pairs of single wheels in each case and all wheels being driven) is arranged substantially above the front driving axle and the drive output being positioned below the upper margin of the chassis frame structure.

In a fire service vehicle of this kind it was considered that the fire extinguisher pump might be situated in the region of the front axle. A vehicle corresponding to the investigation report has not as yet been made in practice. The arrangement of the drive engine and of the fire extinguisher pump establishes an unfavourable weight distribution in the vehicle above the front axle and impedes access to the driving engine, since access from below is obstructed by the driving axle, the axle drives and the drive shafts. At the same time, the vibrations and waste heat from the driving engine are transmitted into the superjacently situated driver's cab, thereby increasing the stress on service personnel in the cab and who are already under considerable strain in the course of an operational trip.

It is also already known that a driving engine may be installed between the two driving axles of a chassis frame - in accordance with GB-PS No.

885,689. The driving engine has post-connected to it a distributor gearbox spaced apart from it and suspended from above between the two main bearers of the chassis frame structure, so that the upper portion is situated below the upper margins of the main bearers of the chassis frame structure.

Although an advantageous position of the centre of gravity of the engine on the chassis frame structure is obtained thereby, it is hardly possible to maintain the required ground clearance since the drive output of the driving engine is consequently substantially at the same level or below that of the axle height of the driving axles. In particular, the incorporation of a distributor gearbox is rendered difficult, an uneven weight distribution on the chassis frame is obtained, and servicing of the driving engine is made difficult by the simultaneous positioning of the driving engine and of the fire extinguisher pump in the region in front of the front axle.

The invention has the object of providing a drive layout for a service vehicle which allows a compact construction and renders manifold possibilities of variation regarding the centre of gravity position of the vehicle as well as the superstructures arranged thereon and the operation and primanly the accessibility for servicing of the drive elements or auxiliary unit, e.g. a fire extinguisher pump, to be simplified.

According to the present invention the driving engine is installed on the chassis frame between a stern of the service vehicle and a section situated between the driving axles and the auxiliary unit is installed on the chassis frame in the region of the forward driving axle. The surprising advantages of this solution consist in that an arrangement of this kind provides an advantageous load distribution with a centre of gravity advantageous for propulsion during operational journeys. Access to the auxiliary unit and in particular if this consists of an extinguisher fluid pump, the connection of the separate extinguisher fluid lines from the end side of the vehicle, are facilitated. The possibility is created that a mechanic for the auxiliary unit may stay in the driver's cab to monitor its operation.

This secures better working conditions for the mechanic since he may stay in the driver's cab under protection against external conditions during a protracted operational period and concentrate wholly on the functionality of the auxiliary unit, e.g. on admixing foaming agents or the like by means of remote control elements, in the case of an extinguisher fluid pump. Furthermore, perfect communication with the other service units may be secured by radio thanks to improved noise damping within the driver's cab. Apart from this, it is also possible to provide the service vehicle at will with a front-wheel drive, rear-wheel drive or allwheel drive. Another advantage consists in that the auxiliary unit may be installed or stowed within the external profile of the vehicle and be protected against damage.

It is also provided that the auxiliary unit may be installed on a section of the chassis frame projecting over the front axle in the direction of travel and may for example, be formed by an extinguisher fluid pump coupled to the PTO via a Cardan shaft.

Thanks to placing the extinguisher fluid pump in the front axle section, the connection of the separate extinguisher fluid hoses or suction hoses may also be made from front end of the vehicle, so that the driving-past of other service vehicles is not obstructed by lateral ducts projecting from the vehicle.

In an embodiment of the invention bearers of the chassis frame have portions projecting forwardly over the front axle and portions projecting rearwardly over the rear axle, and the forwardly projecting portions having support means for the auxiliary unit and the rearwardly directed portions having support means for the driving engine. An approximately symmetrical loading of the chassis frame and thus an advantageous load distribution is obtained with respect to the driving axles, by this arrangement. Access for servicing and repair of the driving engine is simplified at the same time by direct access from the stern side of the service vehicle.The possibility is created furthermore of providing an extinguisher fluid tank in the area between the two axles, that is to say as close as possible to the centre of gravity of the service vehicle, thereby complementarily improving cornering capability. It is possible thereby to obviate costly tippable driver's cabs.

It is advantageous if the transmission forms a compact transmission module together with the intermediate gearbox, the transmission module comprising two output drives extending in the longitudinal direction of the vehicle and aligned in opposed directions as well as a power-take-off pointing in the direction of the front driving axle and is installed on the chassis frame between the two driving axles, whereby a central propulsion force distribution may be obtained and the service vehicle may optionally be equipped with frontwheel drive, rear-wheel drive or all-wheel drive.

According to the invention, it is also possible for the transmission module to incorporate a converter gearbox, a shift-gear transmission, as well as an inter-axle gearbox integrated with the same and in particular having a differential lock, the PTO being arranged in rectilinear extension of the gearbox input shaft coupled to the engine and the axle drive outputs being situated in a place staggered in the direction of the wheel support plane, an electromagnetic clutch being situated between the main gearshaft and the PTO. Thanks to the special configuration of the transmission module, the space requirement drive input and output may be kept very small, and a complementary intermediate transmission between the shift-gear transmission and the inter-axle transmission is obviated by the appropriate configuration of the tramission module.

Furthermore, it is also possible for the transmission module, the drive connections to the driving engine, to the auxiliary unit and the driving engine to be installed between the chassis frame bearers which are spaced apart transversely to the longitudinal direction of the vehicle. It is thereby accomplished that the space above the upper margins of the chassis frame is wholly kept free for superstructure and that servicing-is simplified by access from below to the drive elements. Moreover, the space outside the bearers remains free for superstructures, so that superstructures projecting laterally and downwardly beyond the bearers, for example such as tanks and the like, may be placed on the bearers.

According to the invention, it is possible however that the central longitudinal axis of the drive output of the driving engine and the drive of the auxiliary unit may be situated at the level of the upper margins of forming the chassis frame and between the axes of the vehicle axles and the upper portions of the wheels whereby an advantageous centre of gravity position is obtained.

Furthermore, the commonly very bulky but not heavy items of equipment may be installed above the upper margins of the bearers and the space between and below the bearers remains available for installation of the commonly still very heavy drive elements, intermediate gearbox, distributor gearbox, and the like.

In accordance with the invention, the auxiliary unit may be installed on a section of the bearers extending at an angle to adjacent portions of the chassis frame, angled portions of the bearers being situated in the region between the auxiliary unit and the front driving axle and the bearers from the angled portions towards their ends in inclined manner towards the wheel support plane. This provides an advantageous installation height for the auxiliary unit, and it is possible to lay the suction pipes leading to the tank and the like between the bearers of the chassis frame.

Another embodiment of the invention is advantageous in which the auxiliary unit, particularly being an extinguisher fluid pump, is displaceable with respect to the bearers and is installed on an intermediate frame located in the bearers, and may be displaced from a cartage or stowed position situated within the external vehicle profile and into an operation or servicing position situated at least partially outside the external vehicle profile. An uncomplicated positioning of the auxiliary unit adapted to the different operational conditions may thereby be obtained within and outside the vehicle profile without dismantling. A rapid replacement is also possible in the case of defective auxiliary units which is of great importance in the case of service vehicles so that service readiness may be assured at all times.

In this connection, it is advantageous moreover if the transmissive connection between the transmission module and the auxiliary unit is constructed in longitudinally extendible manner, e.g.

by means of a telescopic Cardan shaft or by a hydraulic power transmission device, since the auxiliary unit may thereby be operated in the extended state and the transmissive connection need not be decoupled for the displacing operations.

Provision is made according to a modified embodiment of the invention for each of the oppositely directed drive outputs for the driving axles to be capable of transmission of the maximum over all torque output of the intermediate gearbox, and that each of the drive outputs is coupled via a Cardan shaft to an axle drive of each of the two driving axles, each of the two drive outputs being seperately engageable, whereby the mode of driving may be adapted to different driving conditions and rear-wheel drive, front-wheel drive or all-wheel drive may be selected in a sample manner. The service vehicle is thereby equipped for all operating conditions likely to be encountered, so that rapid and effective assistance is possible especially in connection with fire service vehicles.

It is also provided for the transmission module to incorporate a hydromechanical torque converter whereof the drive output is coupled to the driving axles as well as via an electromagnetic clutch to the PTO. The hydromechanical torque converter assures a reduction of the stress on the driving engine and a uniform load distribution in the transmission, whilst the PTO may be selectively engaged and impact stresses or vibrations within the transmission may be avoided and its durability may be increased, by utilisation of the electromagnetic clutch.

The invention will now be described, by way of example, with reference to the accompanying partly diagrammatic drawings, in which: Figure 1 is a diagrammatic side elevation partially cut away of a service vehicle comprising a drive system according to the invention, Figure 2 is a plan view of the service vehicle of Figure 1, Figure 3 is a fragmentary sectional view taken on line Ill - Ill of Figure 2 and showing the arrange ment of an auxiliary assembly on the chassis frame structure in end view, Figure 4 is a fragmentary sectional view taken on line IV - IV of Figure 2 showing the arrangement of the transmission module in end view, Figure 5 is a fragmentary sectional view taken on line V - V of Figure 2 and showing the arrangement of the driving engine with respect to the chassis frame, and Figure 6 is a schematic view of a drive layout of a drive system according to the invention.

The service vehicle 1 of Figure 1 comprises a chassis frame 2, a driver's cab 3 and a utility superstructure 4, which may also incorporate an extinguisher fluid tank 5.

The driver's cab 3 and the utility superstructure 4 are shown in outline only and partially cut away so that the propulsion system according to the invention may be seen more clearly.

As apparent from Figures 1 and 2, the vehicle frame 2 comprises two stringers or bearers 6,7 extending in spaced parallel relation to each other in the longitudinal direction of the vehicle. The stringers or bearers 6,7 of the vehicle frame 2 are supported via conventional springing means, for example leaf springs or compressed air springs, on a steerable front driven axle 8 and a rear driven axle 9. The two driven axles 8,9 carry wheels 10 with single tyres. The vehicle frame 2 houses an auxiliary unit 12 formed by an extinguishing fluid pump 13 in the present case in the region 11 projecting beyond the front driven axle 8 and between the two main bearers 6,7. The extinguishing fluid pump is transmissively coupled via a Cardan shaft 14 acting as a driving connection to the transmission module 15 which also is situated between the main bearers 6,7.The Cardan shaft 14 is then coupled to a PTO (power-take-off) 16 of the shift-gear transmission 17. The transmission module 15 has a converter gear 18 apart from the shift-gear transmission 17 and an intermediate inter-axle gearbox 19, housed in the same casing. The transmission module 15 is borne on a transverse bearer 21 extending between and secured to the two main bearers 6,7 via oscillation-damper elements 20.

As more clearly apparent from Figure 1, output drives 22,23 of the inter-axle gearbox 19 are coupled via Cardan shafts 24,25 to axle drives 26,27.

An all-wheel drive vehicle is obtained as a result of this arrangement, in which the two driven axles 8 and 9 may be driven independently of each other.

The rating of the Cardan shafts 24,25 as well as of the intermediate inter-axle gearbox 19 and of the axle drives 26,27 is so selected that the total torque available for propulsion of the service vehicle 1 may be transmitted via either of the two Cardan shafts 24 or 25. The service vehicle 1 may be operated at will with front-wheel drive, rear-wheel drive or all-wheel drive.

An input shaft 28 is coupled to a driving engine 30 via another Cardan shaft 29.

The driving engine 30 is installed on the bearers 6,7 in a region 31 of the vehicle frame 2 projecting beyond the rear driving axle 9. An output drive 32 of the driving engine 30 is situated at the level of an upper margin 33 of the vehicle frame 2.

As a result of the construction of the propulsion system and the arrangement of the individual assemblies in relation to the chassis frame 2 it is provided that the vehicle has an approximately identical load distribution in the region 11,31 projecting beyond the two driving axles 8,9. Thanks to the spacing between the two bearers 6,7 the driving engine 30, the transmission module 15 and the auxiliary assembly 12 may be installed at a small distance from the wheel support plane 34. It is also accomplished that space is reserved for superstructures or cabin sections between the two driving axles 8,9 above and to the sides of the upper margins 33 of the bearers 6,7. An extinguishing fluid tank 5 may thus advantageously be installed as indicated in the region between the two driving axles 8,9.The weight of the transmission module 15 and of the extinguishing fluid tank 5 may thus be divided approximately evenly between the two driving axles 8,9, thereby securing a neutral driving behaviour of the service vehicle 1.

It is possible within the scope of the invention, for the driving engine 30 to be installed at the transmission module 15 or between the transmission module 15 and the rear driving axle 9, and to install the extinguishing fluid tank 5 in the rear section of the service vehicle 1 for example as indicated by pecked lines in Figure 1.

The mounting of the auxiliary assembly 12, comprising an extinguishing fluid pump 13 in this case, is shown in Figure 3. The extinguishing fluid pump 13 is borne on an intermediate frame 36 via oscilllation-damper elements 35, the intermediate frame being located between the facing sides of the main bearers 6,7 and supported on the bearers 6,7 by rollers 37. The intermediate frame 36 may be secured in position in relation to the main bearers 6,7 at extreme positions of forward and rearward movement in relation to the bearers by means of locking bolts 38.

After pivoting a panel 39 in the end side of the driver's cab 3 as denoted by an arrow 40 in Figure 1 it is possible to place the auxiliary assembly 12 in the extinguishing fluid pump 13 in a space present forwardly beyond the vehicle delimitation 41, by movement of the frame 36 forwardly over the roller support 37.

If the extinguishing fluid pump 13 is mounted on an intermediate frame 36 of this kind and not fixedly secured on the vehicle frame 2, the Cardan shaft 14 is constructed as a telescopic shaft as diagrammatically denoted in Figure 2, to allow forward and rearward movement of the auxiliary assembly 12 without interruption of the transmission line.

Instead of the extinguishing fluid pump shown in Figures 1 to 3, it is possible to install any other and optional auxiliary assembly, for example a current generator, a hydraulic system or the like. It is also possible to provide any other kind of mounting for the auxiliary assembly 12 instead of the intermediate frame 36 movable by means of rollers, for example a parallelogram linkage of levers which is secured on the bearers 6,7 of the vehicle frame 2.

Figure 4 shows the mounting of the transmission module 15 between the two bearers 6,7 of the vehicle frame 2. As apparent, the transverse bearer 21 is of U-shaped or cradle form and has its two free extremities connected via the oscillation damper elements 20 to the main bearers 6,7 of the vehicle frame 2. This arrangement allows the transmission module 15 to move under resilient damping in several spatial directions with respect to the vehicle frame 2.

As shown in Figure 5 the driving engine 30 is borne via engine bearers 42 and intervening vibration damper elements 20, equally on the two bearers 6,7 of the vehicle frame 2. The engine bearers 42 are so constructed that the output drive 32 of the driving engine 30 is positioned approximately at the level of the upper margins 33 of the main bearers 6,7 or of an intermediate frame placed thereon.

Figure 6 shows a modified embodiment of a drive layout, in which the drive engine 30 is flangecoupled directly to the transmission module 15.

Furthermore, the converter gear 18 and the shiftgear transmission 17 are more clearly apparent from this illustration. A main gearshaft 43 is coupled to the PTO (power-take-off) 16 via an electromagnetically operated clutch 44. A power consumer, for example the extinguisher fluid pump 13 or another auxiliary assembly 12 such as a generator 45, driven via the PTO 16, may thereby be turned on and off under load. As shown diagrammatically it is possible to flange-couple a hydraulic pump 46 to the PTO 16 and to connect the same with a hydraulic motor 47 flange-coupled to the input shaft of the generator 45, by means of hydraulic pressure pipes 48, into a hydaulic driving block. External light sources or other working implements or the like may be operated by the generator 45.

The converter gear 18 comprises a pump impeller, a turbine wheel and an interposed idler wheel. At a high turbine r.p.m., say 80% of the pump r.p.m., the turbine torque approximates to the pump torque, and the converter by-pass coupling is closed automatically at this time. The converter gear 18 is provided with a braking freq- wheel, which serves the purpose of coupling the drive and turbine shafts in force-locked manner whilst the vehicle is on the overrun, so that the braking action of the engine may be exploited. The multi-gear converter gear produced in the manner of an attachment comprises a multiplate clutch 49 which is hydraulically operated and shiftable under load. All the wheels are in constant engagement.

The transmission control system is devised as an electrohydraulic circuit, which may be embodied as a preselector circuit, i.e. the separate gears are preselected as required on a drive selector, or as an automatic circuit, i.e. the ratios required are selected automatically as a function of the momentary mode of operation. The supply of oil to the converter and to the circuit is provided by means of a gear pump which is installed on the drive shaft or main gearshaft 43 driven by the engine in the transmission module 15.

Within the scope of the invention, it is possible to utilise other forms of transmission instead of the transmission layout described, and for example to apply mechanically shifted transmissions with mechanical clutches or the like. The clutch 44 for the PTO 16 is not restricted to the form of embodiment depicted in Figure 6.

The form of the bearers 6,7 of the vehicle frame 2 may be freely selectible from different forms of construction, for example instead of one-piece continuous bearers, it is possible to utilise multi-sec tional members which may, for example in the region of the angled portions or in other intermediate areas of the longitudinal extents of the bearers, may be joined together by means of bolted joints.

Instead of application to fire service vehicles, the propulsion system according to the invention may evidently and advantageously be utilised for any other category of service vehicles, for example such as elevator vehicles, public utility vehicles or the like.

The direction of travel is commonly denoted by an arrow 50 in the drawings.

Claims

1. A service vehicle having a chassis frame, forward and rearward driving axles and a drive arrangement comprising a driving engine which is transmissively coupled to an auxiliary unit, an intermediate transmission and power-take-off in which the driving engine is situated on the chassis frame between a stern of the service vehicle and a section situated between the driving axles and an auxiliary unit is installed on the chassis frame in the region of the forward driving axle.

2. A service vehicle as claimed in claim 1, in which the auxiliary unit is installed on a portion of the chassis frame projecting forwardly over the front driving axle.

3. A service vehicle as claimed in claim 1 or in claim 2, in which the auxiliary unit is formed by an extinguisher fluid pump coupled to the power-takeoff via a universal joint shaft.

4. A vehicle according to any preceding claim, in which bearers of the chassis frame have portions projecting forwardly over the front driving axle and portions projecting rearwardly over the rear driving axle, the forwardly projecting portions having support means for the auxiliary unit and the rearwardly directed portions having support means for the driving engine.

5. A vehicle according to one of the claims 1 to 4, in which the gearbox and intermediate gearbox form a compact transmission module, the transmission module having two output drives extending in the longitudinal direction of the vehicle and in opposite directions, as well as a power-take-off pointing in the direction of the front driving axle and the transmission module is installed on the chassis frame between the two driving axles.

6. A vehicle according to any of claims 1 to 5, in which the transmission module comprises a shift gear transmission, a converter transmission, and an inter-axle gearbox integrated therein and in particular having a differential lock, the power-takeoff being arranged approximately in rectilinear extension of the transmission input shaft coupled to the driving engine, and the axle drives being situated in a plane displaced in the direction of the wheel support plane, an electromagnetic clutch being installed between the main gearshaft and the PTO (power-take-off).

7. A vehicle according to any of claims 1 to 6, in which the transmission module, the transmissive connections to the driving engine, the auxiliary unit and the driving engine are situated between the two bearers of the chassis frame which are spaced apart from each other transversely to the longitudinal direction of the vehicle.

8. A vehicle according to any preceding claim, in which the central longitudinal axis of the output drive of the driving engine and the drive of the auxiliary unit are situated in the region of the upper margins of the bearers forming the chassis frame and between the axes of the vehicle axles and upper portions of the wheels.

9. A vehicle according to any preceding claim, in which the auxiliary unit is installed on a section of the bearers of the chassis frame which extends at an angle to adjacent portions of the frame, angled portions of the bearers being situated in the region between the auxiliary unit and the front driving axle and the bearers extending at an angle from the angled portion in the direction of their ends towards the wheel support plane.

10. A vehicle according to any preceding claim, in which the auxiliary unit is displaceably mounted with respect to the bearers on an intermediate frame located on the bearers, and for displacement from a stowed position within the external profile of the vehicle, into an operational or service position at least partially outside the vehicle external profile.

11. A vehicle as claimed in claim 10, in which the transmissive connection between the transmission module and the auxiliary unit is longitudinally extendible.

12. A vehicle as claimed in claim 5, in which each of the two oppositely directed output drives for the driving axles is designed for transmission of the maximum output torque of the intermediate gearbox, and that each of the output drives is coupled via a respective Cardan shaft to an axle drive of a respetive one of the two driving axles, each of the two drive outputs being separately engageable.

13. A vehicle according to claim 5, in which the transmission module comprises a hydromechanical torque converter of which the output drive is coupled to the driving axles and, via an electromagnetic clutch to the power-take-off.

14. A vehicle arranged and adapted to operate substantially as described with reference to the accompanying drawings.

15. A vehicle incorporating a drive layout substantially as described with reference to the accompanying drawings.