FR2540586A1 - Coil spring mounting for suspension strut - Google Patents

Abstract

The coil spring of the suspension strut has its ends shaped to enter the thrust plate (1,2) at a set angle and to provide a rolling contact as the spring is compressed. The spring does not snatch on the contact plate and is free to absorb suspension movements. The end windings of the coils are further shaped with decreasing radius so that a fully compressed spring is not inhibited by its closed turns.

Description

New association of a spring and at least one of its cups,

  said association being in particular usable for carrying out a

MAC PHE Rg 01 suspension strut.

  The present invention relates to a new association of a spring and at least one of its cups, this association being in particular usable for producing a suspension strut

MNC PHERSON.

  Coil type springs are very often used in combination with one or two cups, this cup being made up of a metal plate, which can have a specific shape (flat shape, helicotdale shape), on which

  rests on one end of said spring To date, we consider

  rait that the end of the helical spring which rests on said cup should have a shape adapted to that of said cup

  so that the end of said spring is tangent to said cup.

  It has been found, and this constitutes an essential element of the invention, that if the association of the helical spring and of a cup was provided so that the end of the spring is not tangent with the surface of said cup but or on the contrary intersecting with said surface (in other words the end part of the spring which is in contact with the cup makes a non-zero angle with it), it appears, at the point of contact of the end of the spring with the cup, a radial component located at a specific point in the cup (i.e. a component located in a

  plane substantially perpendicular to the axis of the spring) which can pre-

  feel certain advantages during specific uses of the spring.

  It is clear that this interesting property of the asso-

  ciation cup spring remains as long as the end of the spring is

  secant with respect to the cup but that it decreases progressively-

  ment when the end of the spring, due to compression, becomes

  tangent to the surface of the cup If so, we want the as-

  cup spring company considered retains the property described above

  above during all or part of the work (in compression) of the spring, it will be necessary to ensure that the secant character between the end of the spring and the cup is preserved during all or part of this work; for this conservation> one can envisage various solutions but the simplest solution seems to consist in that all or part of the last turn of the spring (turn whose end is in contact with the cup) is less deformable than the other turns of the spring and more precisely, all things

  equal, moreover, that the latter turn has a smaller diameter

  laughing at the diameter of the main turns (we will call the diameter of a turn the diameter of the cylinder around which said turn can be

rolled up).

  In this case, (all or part of the last turn is of a diameter smaller than that of the main turns of the spring),

  it is most often desirable to avoid any part of connection

  dement between the main turns and said end turn this can be easily achieved by ensuring that said turns are arranged so that the cylinders (fictitious) around which each of the turns is wound are tangent one

with the other.

  Finally, it should be noted that it is obvious that this new spring-cup association can be carried out at only one of

  ends of the spring or at both ends of said spring.

  Although the new spring-cup association according to the invention is likely to lead to various uses, a particularly interesting use of this association is found

  be in MAC PHERSON suspensions.

  MAC PHERSON suspensions include an elastic leg

  tick composed of a telescopic shock absorber and a spring arranged concentrically with this shock absorber between two fixed cups, one on the body of the shock absorber, the other on the rod sliding in

said body.

  Said leg, articulated at one end on the vehicle, is integral with the spindle of the wheel cantilevered at its other end It therefore receives from this spindle offset forces

  to which react, in parallel, the spring and the shock absorber.

  The spring, concentric with the shock absorber usually supports that the component of the force which is coaxial it is the slides of the shock absorber which react to the component

  lateral This results in solid friction which influences defa

  vorably on the characteristics of the shock absorber and drive

wear -

  To reduce them, the longitudinal axis of the spring is inclined relative to the axis of the shock absorber, so that it exerts a lateral component which is deduced from that supported by the

backstage.

  This is done by tilting the cups on the axis of

  the shock absorber, they are arranged so that the spring is straight

  line under normal load For any other value of the load, its axis being deformed, the spring risks to buckle; -it is not possible to go very far in this way On the other hand, the bulk of the leg increases , forcing the damper away from the plane of the wheel, which increases the offset of the forces, against this

that we are looking for.

  To solve the problem described, it is clear that one

  can advantageously use a new spring combination-

  cup, according to the present invention, so that the force exerted is oblique with respect to the axis of the body of the shock absorber and always directed substantially towards the fulcrum of the wheel on

floor.

  It will be noted that this objective cannot be achieved with an ordinary helical spring compressed between two cups in the form of a helical ramp, said spring being composed of a number of active turns wound in a helix and terminated at each end by a coaxial turn also wound in a helix, but at the same step as the cup, these two end turns being supported each on one of the cups The spring pressure is

  then distributes evenly over the surface of the cup and results

  pressure aunt passes by the geometric axis of the spring.

  In order to avoid contact between turns, the patent

  2 328 881 proposes a spring whose effort is oblique with an inclination

  naison which depends only on the diameter and the height of the spring These two parameters imposed by other imperatives prevent the resultant efforts to take the desired inclination 'especially for high flexibility springs, the height of the spring and

  therefore the inclination of the resultant varying strongly with the load.

  To direct this force at will, the spring used in the present invention therefore comprises, at least at one end, a support turn whose fotr M introduces a horizontal component

  in the pressing force, when we compress this spring on its cup.

  We can for example, according to the invention, use a spring-cup assembly according to the invention in which, the cup having a conventional helical shape, the end turn of the spring in contact with said cup will have a greater pitch than that of

said cup.

  The value of the horizontal component or flush of the spring is determined by the angle made by the support coil with its cup, by its eccentricity and by its stiffness As the spring is loaded, this angle of the coil d support decreases in

  same time as the height of the spring We arrange for the composition

  horizontal aante evolves in proportion to the load so as to

  keep the inclination of the resultant sufficiently constant.

  It suffices that a single support turn or even a portion of said turn has a greater pitch than the cup for the support force to have a horizontal component and that an equal and opposite reaction is measured on the other cup whatever the shape of the whorl which is applied to it However, if the fulcrum on this cup is not clear, we can observe variations

  orientation of the horizontal component as a function of the load.

  We will have more precision in the orientation of the hunt with a

ad hoc support.

  Note that it may be advantageous to arrange the contact surface between the end of the spring and the cup so that this contact cannot damage either the end of the spring or the surface of the cup. for example make the end of the spring spherical and that a

  also depression of spherical shape is formed in the cup.

  To maintain, in MAC PHERSON suspensions, use

  reading a spring-cup association according to the invention, an orien-

  constant tation of the horizontal component despite variations in load, it is advisable to place the two ends of the spring or more exactly the two points of contact with the cups in

  a msi Pe plane passing through the axis of the spring.

  The cups are perpendicular to the axis of the leg or inclined, they are planar or helical The spring is composed of several coaxial turns of coiled wire whose envelope can be a cylinder, a barrel, a supper or any other form of

  revolution and two extreme turns called support turns.

  This spring can be coaxial or off-center with respect to the shock absorber.

  The accompanying drawings and the description which will follow

  give nonlimiting examples of embodiments of legs

  elastic fitted with springs according to the present invention.

  Figure 1 shows, in elevation an association

  cup spring according to the invention.

  Figure 2 shows, in top view the spring of

Figure 1.

  Figure 3 shows an elastic leg fitted with the

spring of figure 1.

  FIG. 4 is a variant of FIG. 1.

  Let us first refer to Figure 1.

  The spring R according to the invention disposed between two cups 1 and 2 provided with flanges 3, 4 consists of several active turns 5 of metal wire wound in a helix and finished

  at each end by a support turn 6, 7.

  In accordance with the present invention, one of the support turns 6 also wound in a helix at its center 8 outside the axis 9 of the active turns 5 of the spring R and forms an angle a with

  the cup 1 to which it applies by its free end 10.

  Its diameter being smaller than that of the active turns 5, this turn 6 does not bend very much and retains a single point of contact 10 with the cup 1 during most of the stroke of the spring R.

2540} 586

  However, at high loads, it can be assumed that the contact with the cup 1 widens a little provided that the pressure in 10

remains very strong.

  As a result of the oblique contact of the free end 10 of the spring R on the cup 1 the force exerted by the spring on the cup 1 has a horizontal component H and the direction of the resultant F of the forces applied to the cup 1 is inclined relative to the aate 9 of the spring By reaction, the resultant F ′ of the forces applied to the other cup 2 is equal and opposite and therefore has the inclination âP-me whatever the shape of the cup 2 and the turn support 7 which does not apply to it However, if this turn has the conventional forma, we note that the resultants F and F 'do not pass through the axis of the spring and that their orientation f (see FIG. 2) tends to vary with the load This orientation is maintained constant by providing an angle y between the support turn 7 and its cup 2 and the resultants are passed through the spring axis by placing the contact point II of the turn support 7 with the cup 2 in the same vertical plane passing through the axis of the spring as the po int of contact 10 with the cup 1 In other words, the two free ends 10 and II and the axis 9 of the active turns are

in the same plane.

  As mentioned above, to maintain an angle a between the support turn 6 and the cup 1 during most of the load; the support turn is sufficiently rigid This rigidity is due to its small diameter and also to its direct connection to the active turns without a connecting arc, Its propeller is tangent

  in 12 to the propeller 5 of the active turns.

  The spring is mounted on the elastic leg shown

in figure 3.

  The cup 1 is secured to the rod 13 of the piston 14 sliding in the body-15 of the shock absorber to which the cup 2 is fixed The body 15 of the shock absorber is also secured to the

wheel 16 rocket 17.

  The resultant F 'of the forces applied to the cup 2

  passes through the fulcrum 18 of the wheel 17 on the ground The inclination

  its and the orientation of this resultant being constant and the resultant always passing through the axis 9 of the spring 1 it passes

  also always by point 18 whatever the load.

  To have better contact between the free end of the spring and the cup, it is possible, as in FIG. 4) to round the end 19 of the spring and to provide a complementary shape 20 in the cup. The same result can be obtained with a shape

cylindrical, toric or spherical.

  The invention can be applied in particular to the elastic suspension legs of road vehicles, each time that

  needs an oblique effort compared to the elastic legs.

Claims (5)

R E V E N D I C A T I O N S   1 New association of a spring with at least one of its cups, characterized in that at least one of the turns (6) of said spring which is in contact with at least one of the corresponding cups (1) is intersecting with respect to the surface of said cup, that is to say that the axis of the wire constituting said turn at said point of contact makes with the surface of said cup an angle (Kc 2 Association according to claim 1, characterized in that all or portion of the terminal turn which is in contact with said corresponding cup is less deformable than the other turns of said spring.   3 Association according to claim 2, characterized in that the lower deformability of said terminal turn is obtained by producing a terminal turn with a diameter less than diameter of the other turns.   4 Association according to claim 3, characterized in that the cylinders (fictitious) around which are wound the main turns, on the one hand, and the terminal turn, on the other hand, are tangent to each other.   5 Spring conditioned so that it can be used   in an association according to one of claims 1 to 4.   6 MAC PHERSON elastic suspension strut, characterized in that at least one spring-cup association is used according to it one of claims 1 to 4.