FR2577357A1 - IMPROVEMENTS ON ELECTRIC RETARDERS - Google Patents

Abstract

The invention relates to an electric retarder for a vehicle, the stator 1, essentially consisting of an annular flange 2 carrying a ring of almost contiguous coils 3, is mounted cantilever on the axle housing or the gearbox of this vehicle and of which the rotor comprises two discs of magnetic material flanking the stator and themselves mounted cantilevered, in particular by means of arms 10 forming ventilation fins, on a shaft end extending from the housing. The number of coils is increased from eight to ten or twelve, which makes it possible to increase, all other things being equal, the diameter D of the opening recessed in the flange and therefore that of the transmission shaft. (CF DRAWING IN BOPI)

Description

Improvements to electric speed bumps.

  The invention relates to electric retarders

to "eddy currents".

  It concerns more particularly those of these

  sliders, which are mounted directly on a gear case of a motor vehicle transmission, such as

  the crankcase of the bridge or gearbox of that vehicle

  and which comprise an annular inductor stator mounted in the casing on the casing considered using a perforated bell-shaped frame, and a rotor comprising

  two induced discs of ferromagnetic material which encapsulate

  the stator and are both supported by a central plate itself mounted cantilever on a shaft end coming out of the housing, each disk being secured, via a ring of arms forming fins ventilation plate, with a support ring fixed on said plate, and this plate itself being coupled to the end flange of a universal joint on the opposite axial side to that

o is the end of the tree.

  It concerns more particularly, among the

  retarders considered, those in which the stator

  ring conductor is constituted by a crown of coils in even number, axes parallel to that of the retarder,

  carried by a transverse flange of generally annular

  each coil having a cylindrical core of

  revolution in magnetic material which passes through said flange

  that and a winding of electrical wire which surrounds this core, these different coils defining a ring of

  magnetic poles of alternating polarity from close to

  next to each induced disk, and the different coils being separated laterally from each other only the small clearance necessary to avoid jamming

  to assembly and to allow a minimum ventilation.

  The retarders of this type are of interest because their mounting on the housing and on the end of the shaft in question extends only very little the axial distance between these elements and the universal joint.

  considered and in that they engender couples of slow

  relatively high levels of mass and

given.

  In the known embodiments of these slowdowns,

  the number of inductive coils is eight.

If we call:

  - the diameter of the outer circle circumscribed

  rentes reels, which diameter is generally substantially equal to the overall width of the retarder,

  - B the diameter of the inner circle inscribed in the bobbins

  nes, which is generally approximately equal to

  diameter of the central hole hollowed out in the stator flange

  that, - and R ratio A / B, this ratio R is greater than 2 and generally of the order of 2.15 to 2.20 for retarders of the kind considered

  in which the number of coils is equal to eight.

  Under these conditions, if the "width" or transverse horizontal dimension of the space available for the retarder on the vehicle, width delimited for example by the two longitudinal members of the vehicle chassis, is equal to

  A, we can not fit inside the stator of this

  a rotor with a set of rings-central plate

  have an outside diameter C greater than A / 2.

  This diameter C is directly linked to that of the

  transmission torque of the vehicle and therefore to the driving and decelerating torques that may be transmitted by this shaft

  between the engine and the wheels of the vehicle.

  The purpose of the invention is, above all, to increase the di-

  of the rotor elements considered, and thus the couples that can be transmitted by these elements, for a width

off any data from the retarder.

  For this purpose, a value greater than eight, and preferably equal to ten, is given to the even number of coils of the retarders of the kind in question, that is to say for which in particular the coils are almost contiguous laterally and the diameter of the central hole hollowed out in the

  stator flange is at least equal to that of the circle

written in the reels.

  In these circumstances, the ratio R above is

  less than 2 and in general of the order of 1.85.

  In preferred embodiments, recourse is made to

  in addition to one and / or the other of the following

  Since the coils are distributed regularly around the axis of the retarder, the ring formed by these coils is delimited laterally on each side of said axis by two

  vertically stacked coils and the stator flange

  that is delimited laterally by two vertical sides substantially tangent to said coils two by two, - in a retarder according to the previous paragraph, the stator flange has a hexagonal outer contour to

  rounded corners, including, in addition to the two sides,

  vertical tees defined above, four oblique sides substantially tangent each to an extreme high or low coil of the ring and to a coil contiguous thereto

extreme coil.

  The invention comprises, apart from these main provisions, certain other provisions which are used

  preferably at the same time and of which he will be more

question below.

  In what follows, we will describe a mode of

  preferred embodiment of the invention with reference to the drawing

  attached in a way of course not limiting.

  Figure 1 of this drawing shows a portion

  a known electric retarder.

  Figure 2 similarly shows a portion of a

  electrical slinger established according to the invention.

  FIG. 3 is an axial section of the latter

serving according to III-III, figure 2.

  In all cases, the overhang of a crankcase or gearbox of a motor vehicle is mounted cantilevered with an eddy-current retarder of horizontal or substantially horizontal X-axis comprising: an inductor stator 1 comprising a flange of substantially annular shape 2 which carries a corona of coils 3 in an even number 2n arranged so as to form at their ends two annular suites of plane magnetic poles with alternating alternating polarities, - and an induced rotor comprising two discs 4 of ferromagnetic material adapted to axially frame the stator and to scroll each opposite a series of poles of this

  - stator they are separated by a weak game or between-

iron.

  The flange 2 is carried by the casing through

  diaire of a perforated bell-shaped structure (not shown).

  It is itself pierced at its center by a circumferential hole

  5 of relatively large diameter D and in its

  2 smaller holes suitable for receiving

  each one a core 6 which constitutes a coil 3 with

  a winding of electric wire 7 surrounding this core.

  The cores 6 are advantageously terminated by polar extensions 8 reported on their ends

  axial and defining the magnetic poles above.

  The different coils 3 are dimensioned and

  such that they are spaced laterally apart from each other by narrow intervals i, the width of

  these intervals being a few millimeters and generally

  between 2 and 5 mm, in order firstly to avoid the risks of mutual jamming of these coils during

  their assembly and, secondly, to make possible a ventilation

between these coils.

  The diameter A of the outer circle circumscribed to the coils 3 is substantially equal to the overall width L

  of the retarder, which width is that of the flange 2,

  that he himself generally bounded on his perimeter by a

  folded edge of reinforcement and protection 12.

  As for the diameter B of the circle inscribed inside the coils, it is substantially equal to the diameter D of the hole 5, being generally a little smaller than this diameter D. Each of the two discs 4 is connected to a ring 9 by a ring of arm 10 forming ventilation fins (arms of which only one has been shown in FIGS. 1 and 2

  to simplify the drawing) and the two rings 9 are

  on the periphery of a central plateau 11 itself

  secured to the shaft end coming out of the housing (not re-

  present). Of course, the outside diameter C of the portion

  rotor consisting of the rings 9 and the central plate

  tral 11 must always be smaller than the diameter B of

  circle inscribed inside the coils.

  In the known embodiments, the number of

  coils 3 is equal to eight (Figure 1).

  The ratio R between the diameters A and B is then relatively high, namely greater than 2, this ratio being

  generally between 2.15 and 2.20.

  The practical consequence of this state of affairs is that it is not possible to adopt for the diameter C a value

greater than L / 2.

  As the diameter E of the drive shaft of the vehicle and the value of the couples transmissible by this shaft are directly related to this diameter C, we come up against

  there is a limit which proves troublesome in certain

  for which the dimension L is strictly limited, for example because of the distance which exists

  between the two longitudinal members of the vehicle chassis if the

  slider must be housed between these side members.

  To overcome this drawback, according to the invention, the even number of coils 3 is given a higher value.

at eight.

  In the embodiment illustrated in FIGS. 2 and 3, this number is equal to ten, which corresponds to the formation of a ring of ten magnetic poles facing each other.

of each rotor disc 4.

  Experience shows that, under these conditions, in a surprising way, it is possible to obtain, for a given transverse width and a given axial length of the retarder, braking torques at least as

  higher than with the eight coil design, while increasing

  substantially the diameters B and D, and thus the di-

  C. Thus, in a retarder with ten coils according to the above, the ratio R becomes lower

  at 2, being of the order of 1.85: in other words the dia-

  meter C - which is extremely close to the B and D diameters

  can now reach a value greater than L / 2, always

your things are equal elsewhere.

  To reduce as much as possible the overall width L of the retarder, it is advantageous to have the coils of the crown - then regularly distributed about the axis X - so that one finds on each side of this axis two such coils superimposed vertically, that is, symmetrical to each other in relation to the horizontal plane

passing through said axis.

  In addition the flange 2, or more precisely its flanged edge 12, is bounded horizontally by two sides

  vertically practically tangent to these superimposed coils.

  The entire periphery of this flange 2 - and therefore that of its flanged edge 12 - advantageously has the general shape of a hexagon with rounded corners, the two sides

  vertical lines being completed by four mandatory

  each of which is substantially tangential, on the one hand to an extreme high or low coil 3 and, on the other hand, to a coil contiguous to this extreme coil, the six sides being

  connected to each other by rounded sections.

  We still see on the drawings: - in 13, an annular rim coming from molding with each

  disc 4 as well as with the ring 9 and the arms 10 corres-

  the rim defining, with these arms and this disc, channels for the cooling air,

  at 14, recessed bores in the rings 9 for receiving

  see the fixing bolts, - and at 15, the end flange of the universal joint 16, flange

  bolted to the central plate 11.

  For illustrative purposes only, it is indicated that for a

  retarder that can lead to brake torque

  170 m.kg cold and with an overall width

  L of 520 mm, the passage of eight to ten coils according to

  the diameter B from 240 to 280 mm, the ratio R thus going from 2.18 to 1.84 and the

  outer diameters of the windings 7 being themselves

  from 140 to 120 mm: this modification made it possible

  from 180 to 220 mm the diameter E of the flange 15, that is,

  to adopt on a retarder of 170 m.kg a gimbal

  usually reserved for retarders of 250 m.kg.

  As a result of which, and whatever the mode of

  adopted, there is finally a retarder

  the constitution results sufficiently from the foregoing.

  This retarder has many advantages over those previously known and, in particular, the following:

  - it makes it possible to adopt a transmission shaft and car-

  in larger diameter for a given overall width of the retarder, - its mass power is substantially increased, being of the order of 10% when passing from 8 to 10 poles for a given overall width, and for a consumption

overall electric not increased.

  It goes without saying, and as it follows already from the foregoing, the invention is not limited to those of its modes of application and of realization which have

  have been more especially considered; it embraces

  milk, all variants, in particular that where the number

pair of coils would be twelve.

Claims (4)

  1. Electric retarder mounted on a crankcase   gates of a vehicle transmission, comprising an annular inductor stator (1) mounted in cantilever on said housing, stator constituted by an even number of coils (3) of axes parallel to that of the retarder , carried by a transverse flange (2) of generally annular shape, each coil comprising a cylindrical core of revolution (6) made of magnetic material   passing through said flange and a winding of electrical wire   cradle (7) which surrounds this core, these different coils being separated laterally from each other by a small clearance (i), and the flange being hollowed out of a central hole (5) whose diameter (D) is at least equal to that (B) of   circle inscribed inside the coils, and a rotor   carrying two induced disks (4) of ferromagnetic material   that frame the stator and are both suppor-   by a central plate (11) itself mounted door-to-door   false on a shaft end coming out of the housing, each disk being secured by means of an arm ring (10) forming ventilation fins, with a support ring (9) fixed on said plate, and this plate being   itself coupled to the end flange of a car-   dan on the axial side opposite to the one where the shaft end is located, characterized in that the even number of coils is greater than eight.   2. Retarder according to claim 1, characterized   in that the even number of the coils is equal to ten.   3. Retarder according to any one of the   1 and 2, in which the coils (3) are distributed   are regularly around the axis (X) of the retarder, characterized in that the ring formed by these coils is delimited laterally on each side of said axis by two vertically superimposed coils and in that the stator flange (2) is delimited laterally by two vertical sides substantially tangent to said coils two by two.   4. Retarder according to claim 3, characterized   in that the stator flange (2) has a hexagonal outer contour with rounded corners, the contour comprising, in addition to the two vertical sides defined above, four oblique sides substantially each tangent to a coil   extreme high or low of the crown and a coil con tigger to this extreme coil.