GB2197924A

GB2197924A - Decelerator device

Info

Publication number: GB2197924A
Application number: GB08727721A
Authority: GB
Inventors: Carlo Gheddo; Dominique Berger
Original assignee: Carbone Lorraine SA; Iveco Fiat SpA
Current assignee: Mersen SA; Iveco SpA
Priority date: 1986-11-28
Filing date: 1987-11-26
Publication date: 1988-06-02
Anticipated expiration: 2007-11-26
Also published as: GB8727721D0; FR2607566A1; DE3740373A1; IT1215200B; IT8667889A0; GB2197924B

Description

DECELERATOR DEVICE FOR 11DUSTRIAL VEHICLES 2 19 7 9 f'.: 4 This invention

relates to a decelerator device for industrial vehicles, ie a device able to reduce the vehicle speed along descending paths in order to obviate or at least decrease the use of the service brakes. Known currently used decelerator devices are generally of hydraulic or electromagnetic type. The former have the drawback of excessively large weight (of the order of 300 kg), whereas the latter have a very high current consumption during their operation, and therefore need suitable accumulators to be disposed in the vehicles on which they are mounted. Both decelerator devices of the aforespecified type are also excessively bulky.

The object of the present invention is to ProvLde a decelerator device for industrial vehicles able to obviate the drawbacks of the aforesaid devices of known type. This object is attained according to the present invention by a decelerator device for an industrial vehicle, characterised by comprising: - first friction means to be supported by a fixed structure of id vehicle; Sall. second friction means to be supported by a mobile portion of the motion transmission of said vehicle; and - actuator means arranged to move said first friction means relative to said second friction means, or viceversa, between a rest position in which said first and second friction means do 2 - L ' not substantially transfer friction forces, and a working position in which said first and second friction means transfer friction forces able to determine a speed reduction in the mobile portion of said motion transmission, and consequently a 5 deceleration of said vehicle. The present invention will be more apparent from the description of a preferred embodiment thereof given by way of non-limiting example hereinafter with reference to the accompanying drawing, which shows a sectional view of a portion of a decelerator device 10 constructed in accordance with the present invention. In this drawing, the reference numeral I indicates overall a decelerator device for an industrial vehicle. The device I comprises essentially a stator member 2 conveLiently connected to the gearbox casing 3, and a rotor member 4 conveniently interposed and' fixed between terminal flanges 5, 6 respectively 'on shal of the gearbox outDut shaft 7 and the transmissi ft 8.

Kore particularly, the stator member 2 comprises substantially an annular flange 11 which is connected to a respective portioL 12 of the gearbox casing 3 by a plurality of bolts 13. The stator member 2 is also provided with a cylindrical element 15 having one end welded to the flange 11 and its opposite end connected to a head flange 16 by a plurality of bolts 17. The rotor member 4 has substantially a cup- shaped structure with a central portion 15 clamped between the flanges 5, r3 by a plurality of bolts 19, and a cylindrical lateral wall 20, one end 21 of which extends into proximity with the flange 11 of the stator member 2.

Between the wall 20 of the rotor member 4 and a corresponding lateral wall 23 of the cylindrical element 15 there is formed an annular chamber 24, the interior of which houses a plurality of annular discs 25, 26, 27, 28, 29, 30 respectively, arranged in a pack. More particularly, the discs 25, 26, 28 and 29 are formed of carbon composite, whereas the discs 27 and 30 are of metal type, preferably steel. In addition, the discs 25, 29 and 30 comprise, on that side thereof facing radially outwards, appendices 32, 33, 34 which engage a respective seat (not shown) provided in the lat-eral wall 23 of the cylindrical element 15, in order to remain angularly coupled to this latter. Likewise, the discs 26, 27 and 28 comprise, on that side thereof facing inwards, respective radial appendices 36, 37, 38 which engage a corresponding seat (not shown) formed in the wall 20 of the rotor member 4 so as to angularly couple the discs 26, 27 and 28 to Sid rotor memb=-r. The discs 27 and 30 comprise through radial bores 41, 42 which connect grooves 43 provided on the inside of the wall 23 of the cylindrical element 15 to grooves 44 provided on the outside of the lateral wall 20 of the rotor member 4, in order to allow a certain air change through said annular chamber 24. This air change is further favoured by feeding compressed air from the vehicle pneumatic system through pipes 45 connected to connectors 46 distributed uniformly around the annular flange 11 of the stator member 2. The discs 27 consist substantially of two mutually facing circular plates connected together by a plurality off spacers 47 defining said through bores 41.

Specifically, the spacers 47 are located in a suitable manner, ie partly inclined, to facilitate maximum flow of the compressed air fed through the connectors 46. The path followed by the air is indicated by the arrows on the accompanying drawing. Finally, by means of its annular head flange 16, the cylindrical element 15 supports actuators 52 (conveniently fed hydraulically or pneumatically), each of which is provided with a sliding piston 53 arranged to compress the pack of discs 25, 26, 27, 28, 29, 30 in order to generate a high friction pressure between the m-jtual'Ly facing surfaces of the carbon discs carried by the Stator member 2 and rotor member 4 respectively. Conveniently the actuators 52 are disposed equidistant and are of a number sufficient to ensure the thrust necessary for proper operation of the decelerator device 1.

The operation of the device I is as follows. In the absence of feed to the actuators 52, there is no compacting of the discs eDclosed within the chamber 24. Consequently, the discs 26 and 28 are rotated (together with the interposed disc 27) by the rotor member 4 without substantially interfering with the discs 25 and 29. Ron-interference between the rotor and stator discs could be ensured by springs (not shown) which, by means of suitable tie rods connected to the metal stator discs, define the mutual positioning between the stator and rotor discs. On feeding the actuators 52, the pistons 53 move to compact all the discs contained within the chamber 24, to generate between t the discs 25 and 26 and between the discs 28 and 29 respectively, a transfer of friction forces which leads to consequent reduction In the rotation speed of the shafts 7 and 8 and consequently a deceleration of the vehicle. If the actuators 52 are disposed in such a manner as to selectively control the position of the respective pistons 53, a suitable selector could be provided upstream and conveniently located in the driver's cab for operation by the driver, in order to allow him to choose the deceleration pattern. It will be noted that during the compacting of said discs, the steel discs 27 and 30 besides supporting the carbon discs and allowing correct distribution of the thrust generated by the actuator elements 52 (which are conveniently distributed uniformly about the entire circumference), also absorb the reaction of the keyed connections 32, 33, 34 and 36, 37, 38 on the stator and rotor members, and allow dispersal of the heat produced by the braking friction by means of the through bores 42, 41 or chambers 43, 44, aided in this function by the "fan efiect" determined by the spacers 47 of the disc 27 and by the said flow of compressed air. The advantages of the decelerator device constructed in accordance with the present invention are apparent by an examination of its characteristics. Firstly, the use of carbon discs, which are known to have the capacity to resist thermal overload even for relatively long periods such as those for which a decelerator would be used (of the order of 30-40 seconds) enables a decelerator device to be formed which is of small weight and overall size. It is also apparent that because of the principle used to obtain deceleration, there is no longer any requirement for the considerable electric current which is necessary in electromagnetic decelerators. Finally, it is apparent that modifications can be made to the described decelerator device 1, but without leaving the scope of the present invention. For example, the proposed structure is not a limiting factor, nor is the number of carbon discs used, which could be conveniently increased or decreased. It is also apparent that the stator member 2 could be supported by any fixed structure of the vehicle and that, likewise, the rotor member 4 could be supported by any mobile portion forming part of the vehicle motion transmission. For example, the decelerator device according to the invention could also be mounted not at the gearbox exit but, with suitable mcdifications, directly on the transmission by interposing it between two portions thereof.

Claims

PATENT CLAIXS

I. A decelerator device for an Industrial vehicle, cbaracterised by conprising:

- first friction means to be supported by a fixed structure of said vehicle; - second friction means to be supported by a mobile portion of the motion transmission of said vehicle; and - actuator means arranged to nove said first friction 1Deans relative to said second friction means, or viceversa, between a rest position in which said first and second friction neaDs do not substantially transfer friction forces, and a working position in which s-zJd first and second friction means- transfer friction forces able to determine a speed reduction in the =b-i-ie portion of said motion transmission, and consequently a deceleration of said vehicle.

2. A device as claimed in claim 1, characterised in thaz said first and second friction means of material of high resistance to thermal overload.

3. A device as clained in claim 2, characterised in that said material substantially consists of carbon composite.

4. A device as claimed 1D any one of the preceding claims, characterised in that said first and second friction means have a structure in the form of annular discs disposed In a pack, and are arranged to be pressed against: each other in the axial direction by said actuator means are 5. A device as claimed In claim 4, characterised by comprising a pair of said annular discs forming said friction means and between which a metal support disc Interposed.

6. A device as claimed in claim 5, characterised by comprising a rotor member conveniently interposed between s.cid ibetal disc and said annular discs an one side and said mobile portion of said motion transnissioD on the other side, said metal disc and the relative annular led friction discs adjacent thereto beng angularly coup.

d rotor member to sal.

A device as claiwed in clain 6, characterised in tha-, d first friction said anDj,ar friction discs forzins sa.'.U meaLc- are conven4.eD'L."Ly supported by a Etator iD--Dbe-r COnVeL2e2t-Y arranged to be SUPPOrted by SbId -fixe-- s-,ruct-ure c-' said ve-r-clc-.

A device as claimed IL C1bin 7, ch-aracterised by co=,-,7!Eing at -1east one auxili&Ty Detal interposed between said actuator means 16 , 5 disc and an annular friction disc of said first friction mpans; said auxiliary dis: and said annular dIscs formng said first friction means being angularly coupled to said stator member g. A device as claimed in clain 8, characterised in that said auxiliary disc and said metal disc comprise a plurality of through bores cooperatLE With corresponding seats provided in said stb'or menber an,' rotor member to fort aeration con--u-ts ab'e to disperse the beet which Is produced, when In use, by said first friction means. and second friction means 10. A device as claimed In any one of the preceding claims, characterised in that said actuator means are of hydraulic type.

11. A device as claimed in any one of claims 1 to 9.

characterised in that said actuator mans are of pneumatic type.

in.

4 A decelerator device for an industrial vehicle substantially as described with reference to the accompanying drawing.