KR101565168B1 - pulley assembly - Google Patents

Abstract

A pulley assembly (1) for a flexible motor vehicle transmission comprising a support member (2; 4) rotatable about a shaft (A), a support member A pulley 3 employed to move with the belt so as to be rotatable relative to the support member 2 and connected to the support member 2; a spiral spring 6 inserted between the support member 2 and the pulley 3; And a sliding wall (10) which is moved by one of the support members (2; 4) or pulleys to engage the support member (2; 4) to the pulley (3) And a sliding portion 16 which is resiliently loaded in a radial direction and wherein the sliding portion 16 is exchanged between the first contact region 17 and the sliding portion 16 and the sliding wall 10 Defining at least one second contact area (19; 66) in which a static pressure is concentrated, the first and second contacts Station (17; 18, 19; 66) are each yirumyeonseo each other at a distance.

Description

Pulley assembly {PULLEY ASSEMBLY}

The present invention relates to a pulley assembly, particularly a pulley assembly for a drive belt, which is employed for connecting a plurality of accessory members to a crankshaft of an internal combustion engine.

A pulley assembly including a hub adapted to be connected to the crankshaft of the internal combustion engine and a pulley adapted to cooperate with the belt of the accessory drive and adapted to be pivotally connected to the hub by a spiral spring, ) Are known.

Such known assemblies also include an annular seismic mass, which is generally coaxial to the hub, and a torsional damper, which constitutes an elastic connection element arranged between the hub and the seismic mass. ).

In use, the helical spring is connected to the rotation of the hub and pulley and provides a relatively low stiffness to filter the torsional vibration of the crankshaft and to prevent such vibration from being transmitted to the accessory drive.

In known pulley assemblies, the pulley includes a cylindrical wall radially connected to the hub by a bushing and defining a central cavity for receiving a portion of the hub and helical spring. The helical spring includes a first end connected to the hub and a second end interposed in radial interference with the cylindrical wall.

During operation, the pulley may advance the hub and the second end may slide relative to the cylindrical wall if the maximum transmittable torque value is exceeded. Such a condition occurs immediately after a sudden deceleration while turning the crank of the engine when there is a significant change in torque, or when the crankshaft rotates at a relatively slow angular speed while the associated drive is moved by inertia at a high angular speed.

In known pulley assemblies, the result of radial eccentric pressure acting between the second end of the spring and the cylindrical wall tends to wear and creates additional stress on the bushing with a limited working life.

It is an object of the present invention to make a pulley assembly without the drawback mentioned above.

The object of the present invention is achieved by a pulley assembly as defined in claim 1.

For a better understanding of the present invention, and not by way of limitation, preferred embodiments will be described with reference to the accompanying drawings.

1 is a radial cross-sectional view of a pulley assembly according to the present invention.

Figure 2 is a perspective view of the pulley assembly of Figure 1 with components removed for clarity.

Figure 3 is a bottom view of the components of the pulley assembly of Figure 1;

4 is a cross-sectional view of FIG. 3 taken along line IV-IV of FIG. 3;

Figure 5 is a rear view of Figure 3;

Figure 6 is a bottom view of a second component of a pulley assembly in accordance with the present invention.

7 is a cross-sectional view of FIG. 6 taken along line VII-VII of FIG.

8 is a cross-sectional view taken along line VIII-VIII of FIG.

1, reference numeral 1 denotes a hub 2 which is adapted to be connected to the crankshaft of the internal combustion engine, a pulley 3 which is radially supported by the hub 2, and a torsional vibration dynamic damper And a spiral spring 6 for rotationally connecting the hub 2 to the pulley 3 and the semi-mass mass 4 connected to the hub 2 by means of a band 5 of elastic material The pulley assembly as a whole.

In particular, the hub 2 defines an annular cavity 45 and includes a tubular element 46 having an axis A as a whole, a side wall 48 projecting radially from the tubular element 46, And includes a cylindrical wall 47 which is radially outward.

The pulley 3 is preferably formed as a single piece and has a crown which defines a plurality of grooves 8 coaxial with the axis A and adapted to cooperate with a belt (not shown) A side wall 9 perpendicular to the axis A and protruding toward the axis A from the side of the crown 7 and a cylindrical wall 47 projecting from under the crown 7 and projecting from the cylindrical wall 47 of the hub 2 And a cylindrical wall 10 having a smaller diameter.

In addition, the side wall 9 defines a circular opening 11 having a diameter smaller than the diameter of the cylindrical wall 10.

The pulley 3 is inserted into the hub 2 so that the side wall 9 axially closes the annular cavity 45 and the cylindrical wall 47 surrounds the cylindrical wall 10 in the radial direction.

More specifically, imagine a bushing 50 that is inserted into the annular cavity 45 between the cylindrical wall 10 and the cylindrical wall 47 to support the pulley 3 radially to the hub 2. [ The bushing 50 provides a transversal L-section and includes a cylindrical portion 51 and a side wall 9, which are radially inserted between the cylindrical walls 10, 47 as a whole, Includes a flange portion 52 between an abutting portion 53 that projects radially at the free distal end of the cylindrical wall 47.

The distal end 49 of the tubular element 46 intersects the circular opening 11 and the pulley assembly 1 is bolted to the distal end 49 to secure the pulley 3 and the hub 2 in the axial direction And includes a flat retaining ring 54 that is integral. When the retaining ring 54 is inserted into the tubular element 46 the pulley 3 is moved to the flange portion 50 of the bushing 50 in order to recover axial movement and allow relative rotation of the hub 2 52 and the proximal portion 53 of the hub 2, respectively. In particular, the retaining ring 54 has an axial annular ridge 54 which defines a centring seat for connecting the tube element 47 and the sidewall 9 to a peripheral portion 56, ; 55). In addition, a ring 57, which is an anti-friction material, is inserted axially between the peripheral portion 56 and the side wall 9. The ring 57 also has a specific seat defined by the side wall 9 to prevent possible debris from accumulating between the ring 57 and the respective contact surfaces defined by the side wall 9 and the retaining ring 54. [ Respectively. When the pulley 3 is mounted on the hub 2 a portion of the circular wall 47, the crown 7 and the side wall 9 is at least partly provided for receiving the sesimmic mass 4 and the band 5 The boundary of the annular cavity 12 is defined. In addition, the annular cavity 12 surrounds the annular cavity 45 which receives the spring 6 in a radial direction.

The spring 6, which is generally made of a more rigid material than that used to make the cylindrical wall 10, has a spiral portion 14 (Fig. 2), within the radial direction of the spiral portion 14, And a sliding portion 16 which is radially outward relative to the spiral portion 14 and cooperates with the cylindrical wall 10.

Preferably, the spring 6 is connected to the hub 2 including a friction mode. For example, the distal end portion 15 is radially folded toward the axis A and inserted in the recess defined by the hub 2. Another possible connection is a connection by a stiff fastening element, such as a pin or shape coupling.

In addition, the sliding portion 16 provides a medium plane P perpendicular to the axis A and has a support portion 61 integral with the spiral portion 14, a free end portion 18 of the support portion 61, Connected runner 17 and a runner 19 connected to the portion 66 of the sliding portion 16 at a distance from the runner 17 in the tangential direction. The support 61 also provides an intermediate portion 67 that is tangentially inserted between the free end portion 18 and the portion 66 at a radial distance from the cylindrical wall 10.

The spring 6 is mounted by radial interference in the annular cavity 45 and the runners 17 and 19 are defined by a sliding wall defined by the cylindrical wall 10 and facing the axis A is preloaded by a radial push of the spiral portion 14 with respect to the sliding surface 20.

The pulley assembly 1 also includes a stop device 21 for locking the sliding of the sliding portion 16 along the cylindrical wall 10.

The stop 21 comprises a pair of abutting elements 25 projecting radially in the runner 17 and the cylindrical wall 10 and axially spaced to define a boundary of the hollow 26, .

Preferably, the adjacent element 25 forms a monolith with the cylindrical wall 10.

According to a preferred embodiment, the pulley assembly 1 also includes a damping device 40 for eliminating at least some of the kinetic energy due to the relative speed between the hub 2 and the pulley 3. The damping device 40 includes a wedge 23 arranged on the opposite side of the runner 17 relative to the runner 17 and the adjacent element 25. In addition, the wedge 23 defines an inclined plane 24 that is symmetrically arranged in the midplane of the hole 26, facing the hole 26.

3 to 5 show a runner 17 integrally including an anchoring portion 27 connected to the free end portion 18 and a head portion 28 projecting from the anchoring portion 27 along the tangential direction do.

The width of the anchoring portion 27 is wider than the width of the support portion 61 and the covering wall 29 and the free end portion 18 radially inserted between the cylindrical wall 10 and the free end portion 18 And a pair of side walls 30 projecting from a cover wall 29 for covering each side 62.

The side wall 30 defines a resting surface 32 defined by the cover wall 29 and arranged in contact with the back 63 of the support 61. The resting surface 32 provides convex generating lines at least in its central portion along the direction of the axis A. [ The curving radius of the generation line of the resting surface 32 is essentially equal to the anticlastic bending radius of the back 63 and is particularly similar to the anticlastic bending radius of the back symmetry segment 63, It is the same as the bending radius.

4, the cover wall 29 follows a circumference arch profile that is concentric with the axis A and provides a substantially constant thickness in a plane perpendicular to the axis A.

The anchoring portion 27 also includes an abutting wall 31, which is vertically arranged on both the side wall 30 and the cover wall 29. [

The head portion 28 protrudes along the profile of the cover wall 29 between the adjacent walls 31 and provides a width that can engage the gap in the hole 26.

In addition, the head portion 28 defines a chamfer 33 that selectively cooperates with the sloping surface 24 in opposition to the sliding surface 20.

Preferably, at least the anchoring portion 27 is made by sintering the metal powder and the cover wall 29 is coated by the polymeric material layer 34 in direct contact with the sliding surface 20. Preferably, the adjacent wall 31 and head portion 28 are also coated with a layer 34.

For example, the polymeric material preferably comprises an epoxy resin combined with a fluorinated plastomer.

The runner 19 (Figures 6-8) also has a constant thickness supported by the cover wall 35 and the cover wall 35 defining a functionally similar convex surface 36 with the resting surface 32 A polymeric material layer 34, and a pair of side walls 37 that are functionally similar to the side wall 30.

Preferably, the cover wall 35 provides a back surface 58 having a cylindrical profile coaxial with the axis A and a thickness varying along the tangential direction to make uniform pressure distribution uniform.

In particular, the thickness S1 of the proximal portion 59 of the cover wall 35 facing the runner 17 is greater than the thickness S1 of the cover wall 35 arranged opposite the tangential direction of the runner 17 with respect to the proximal portion 59 (S2) of the distal portion (60) of the distal portion (60). In particular, the thickness continuously increases from the distal portion 60 toward the proximal portion 59.

According to the embodiment shown in Fig. 7, the convex surface 36 provides a circumferential arch profile with a radius smaller than the radius of the back surface 58 that is uniquely arranged for this purpose in the cross-section along the plane P, The thickness of the cover wall 35 changes.

In addition, the cover wall 35 includes a protrusion 42 that protrudes from the same side as the side wall 37 to the center. In use, a hole, possibly a blank hole, and a projection are formed in the rear 63 of the support 61 to ensure tight connection for the shape coupling in the tangential direction. In addition, the cover wall 35 defines a pair of reliefs 43 arranged parallel to the side wall 41 and delimiting the convex surface 36. The relief 43 is also provided to the runner 17 and possibly also to accommodate a generally irregular edge 64 of the side 62 of the spring 6.

Operation of the pulley assembly 1 is as follows.

When the crankshaft turns off the attached drive, the hub 2 draws the pulley 3 and delivers a positive torque that the runner 17 approaches the adjacent element 25. Thus, the adjacent walls 31 of the runner 17 each oppose the adjacent element 25 and the sliding portion 16 is in the rest position.

In particular, it is important that the runner 17 can not exceed all the running positive positive torque or adjacent element 25 at the specified value. One way to achieve such an effect is to adapt the contact surface between the adjacent wall 31 and the adjacent element 25 so that the value of the possible force component parallel to the contact surface and facing the hub 2 is negligible with respect to the frictional forces acting on the contact surface I will. For example, the contact surface may be essentially parallel to the radial direction.

The spiral portion 14 of the hub 6 tends to unwind and the support portion 61 adheres to the resting surface 32 completely by the effect of the transmitted torque when the hub 2 shuts off the pulley 3 .

In this state, the static torque transmitted between the hub 2 and the pulley 3 is proportional to the relative angular position between the hub 2 and the pulley 3.

In particular, the cover wall 35 distributes the radial pressure, which is the sum of the two contributions. The first contribution is associated with the action of the spiral portion 14 and is mainly concentrated in the distal portion 60. The second contribution is due to the radial bending of the support 61 due to the effect of the increasing thickness of the cover wall 35. In particular, the proximal portion 59 provides an increasing thickness S1 with respect to the thickness S2 of the distal portion 60, thus inducing the bending of the wall 61. [ The contribution of such deflection tends to focus on the proximal portion 59 and the sum of the two radial contributions when the hub 2 is pulling the pulley 3 and the spiral portion 14 is under load is radially Calculate the thickness variation so that it is essentially uniformly distributed along the tangential direction of the pressure.

During operation, when the hub 2 shuts off the pulley 3, because the sliding portion 16 is preloaded radially with respect to the cylindrical wall 10, the runner 17 is always in contact with the adjacent element 25 On the other hand, the helical portion 14 filters the torsional vibration transmitted to the hub 2 by the crankshaft.

In case of a sudden deceleration, the inertia of the attached transmission transfers negative torque from the adjacent element 25 to the pulley assembly 1 at a distance from the runner 17.

In particular, such a torque value is greater than the threshold of the torque that can be delivered merely by the friction between the sliding portion 16 and the cylindrical wall 10. [ Such a threshold value depends on the friction coefficient between the runners 17,19 and the sliding surface and on the preload of the radius dimension of the sliding portion 16 with respect to the cylindrical wall 10. [

Under the bias of a negative torque higher than the threshold value, the sliding portion 16 slides in the cylindrical wall 10 and is driven axially by respective side walls 30, 37 cooperating with the side walls 9, The runner 17 is separated from the adjacent element 25 and in this way creates a joint in the previous effect.

The rotation of the pulley 3 is independent of the angular position of the hub 2 since the friction is exerted by the sliding portion 16 when the runner 19 slides on the sliding surface 20, 2) and the pulley 3, respectively. In addition, in the negative torque state, the spiral portion 14 tends to roll and the dispersion of the radial pressure along the cover wall 35 is concentrated at the proximal portion 59, rather than being constant in the tangential direction. However, the absolute value of the contact radial pressure when the spiral 14 is wound down is less than that described when the spiral portion 14 is released and less pressingly on the proximal portion 59.

When the motor accelerates again, once the average value of the torque transmitted by the crankshaft exceeds the threshold, the hub 2 tends to be ahead of the pulley 3 and the sliding portion 16 is moved toward the adjacent element 25 Sliding on the sliding surface 20. At the same time, the spiral portion 14 is loosened and the support portion 61 is completely fixed to the convex surface 36.

In particular, before the runner 17 abuts against the adjacent element 25, the chamfer 33 slides on the ramp 24 and induces an increase in the radial force exerted by the runner 17 on the ramp 24 . The damping device 40 thus tends to eliminate kinetic energy by friction in order to reduce the relative speed between the hub 2 and the pulley 3 and weaken the impact on the adjacent element 25 .

In addition, the runners 17, 19 are tangentially spaced so that the total resultant force of the radial forces exerted by the spring 6 on the pulley 3 by the runners 17, 19 is reduced. In particular, the total resultant force is the sum of partial combined forces R1 and R2 acting on the runner 17 and runner 19, respectively, and the total resultant force is minimum when the partial force is 180 degrees apart. Since the pressure concentrates on the runners 17,19 with respect to the intermediate portion 67, which distance radially from the sliding surface 20 along the arch separating the runners 17,19 from each other, Is achieved.

The respective distances of the partial resultant forces R1 and R2 may vary with respect to the 180 degree value and it would be sufficient to have 150 degrees to 210 degrees to advantageously reduce the total force value of the radial force. The way to represent each distance between R1 and R2 is to consider the homologous point (C1, C2) of each runner (17, 19). For example, the coincidence points C1, C2 may be the respective centers 65, 70 of the respective theoretical contact areas defined in the runners 17, 19 or the respective ends 65, 70 of the runners 17, 19. In this embodiment, the theoretical contact area is defined by the entire curved surface on which the rectangular plane of the layer 34 of the runner 19 grows, and by a rectangular plane with bounded boundaries between the distal end 65 and the abutment 31 In the layer 34 of the runner 17, by a curved surface.

The advantages of this pulley assembly are as follows.

The fact that the contact area, ie, the runners 17, 19 with which the contact pressure is concentrated, distances in the tangential direction means that the vector sum of each of the resultant forces R1, R2 is the product of the product of the Carnot's theorem R1, R2) by the square root of the cosine of the angle formed between the elements of R1 and R2. Therefore, the radial stress on the bushing 5 is reduced.

In addition, the fact that the runners 17, 19 place a distance in the tangential direction allows to determine the forcing condition in the spiral portion 14 similar to the ideal connection and thus the internal tension in the spiral portion 14 itself, Can be reduced.

The presence of the runners 17,19 can control the wear of the cylindrical wall 10, which is generally formed of a softer material than the material used to make the spring 6.

The radial pressure exerted by the support portion 61 through the fact that the bending radius in the plane including the axis A of the rear portion 63 is equal to the bending radius of the resting wall 31 and the convex wall 36 To be distributed uniformly and substantially symmetrically with respect to the intermediate plane (P). In this way, a torque acting on a plane parallel to the axis A is avoided.

By means of the varying thickness of the cover wall 35 and by means of the relief 43 it is possible to distribute the contact pressure better and consequently to less wear on the runners 17,19. In particular, the relief 43 compensates for the high irregularity of the edge 64.

An anchoring portion 27 and an adjacent wall 31 can be produced by sintering to attain high mechanical impact resistance characteristics.

The side walls 30, 37 prevent the support 61 directly against the side wall 9 and prevent it from being damaged.

It is possible to reduce the noise and stress in the runners 17 and 19 by using a damping device acting when reaching the stop position.

It will be apparent that modifications and variations of the pulley assembly 1 described and described herein can be made without departing from the scope of protection of the invention as defined by the appended claims.

The sliding portion 16 may be formed differently. For example, the intermediate portion 67 may also be coated with a contact layer during use, while the cylindrical wall 10 includes runners 17,19 for forming a single cover layer. In this case the free end portion 18 and the portion 66 provide a larger bending radius with respect to the radius of the sliding surface 20 of the cylindrical wall 10 when the spring 6 is in the pre- You may. In this way, when the spring 6 is inserted, the dispersion of the pressure is concentrated at the free end portion 18 and the portion 66. Particularly, even if the intermediate portion 67 is in contact with the sliding surface 20, the pressure at the free end portion 18 and at the portion 66 is greater than the peak value L3 at the intermediate portion 67 0.0 > L1 < / RTI > and L2.

Advantageously, such a contact pressure dispersion allows obtaining radial summation with equally small values.

The runners 17,19 may be connected to the support 61 by a layer of adhesive material and may not be provided with a projection defining a shape coupling. For example, they may simply consist of an adhesive layer.

Alternatively, the at least one runner 17, 19, and preferably the runner 19, may be co-molded directly into the support 61.

In the embodiment in which the runner 17 is molded together, the geometric features for the stop device 21 and / or for the damping device 40, for example the chamfer 33, 18).

Preferably, when the runners 17 and 19 are molded together, a fiber-reinforced composite polymeric material, such as carbon fibers, including friction materials such as fluorinated polymers, matrix material.

According to another embodiment, at least one runner (17, 19) provides a pair of projections projecting from respective side walls. The projection is received in a corresponding hollow formed in a side 62 of the support 61 to define a connection for shape coupling in a tangential direction.

In addition, you can imagine a different stop device than the one described. In particular in the annular cavity 45, which is defined in the tangential direction by the respective adjacent surfaces and which is formed in the side wall 9 of the pulley 3. Such recesses accommodate one of the side walls 30, 37 of the runners 17, 19 that are locked when cooperating with one of the adjacent surfaces.

The damping device may also be different from that described. In particular, imagine a suitably shaped ridge to define both the stop position and the inclined plane necessary to lower the relative kinetic energy on the hub 2 and the pulley 3.

In particular, the shaped ridges define adjacent surfaces and curved surfaces arranged in the radial direction to engage the sliding surface 20 on adjacent surfaces.

When the pulley 3 includes the above-described molded ridges, the sliding portion 16 may comprise a co-molded runner 17. In this case, the free end 18 defines a chamfer that cooperates with the chamfer 33 and cooperates with the curved surface to obtain a damping effect. The free end portion 18 also defines a head portion that suitably engages the chamfer and cooperates against the adjacent surface of the ridge to define a stop position of the sliding portion 16. [ The head portion may be covered by the layer or may be in direct contact between the head portion metal and the formed ridge metal.

In the simplified configuration the pulley assembly 1 may not be provided with a stop device 21 and the sliding portion 16 and the pulley 3 may be provided between the sliding portion 16 and the cylindrical wall 10 It may be combined only by friction. In this case, the contact layer of the sliding surface 20 may be formed of a friction material, such as a lining or the like.

The sliding portion 16 may also be about 120 [deg.] Formed by including a third runner that is angled with the runners 17, 19 and preferably equidistantly spaced. The stability of the sliding portion 16 can be further improved with respect to the movement in the direction parallel to the axis A due to the presence of the third runner. In addition, when the angle is 120 degrees, the effect of radially no force is preserved.

The sliding portion 16 is free of the runners 17 and 19 and the free end portion 18 and the portion 66 also contact the cylindrical wall 10 directly. The corresponding peak value L3 of the static pressure must be lower than L1, L2 of the respective free end portion 18 and portion 66, although the intermediate portion 67 may also be in contact with the cylindrical wall 10 .

Claims (25)

A pulley assembly (1) for a flexible motor vehicle transmission, A support member 2 (4) rotatable with respect to the axis A, A pulley (3) employed to move with the belt and connected to said support member (2; 4) so as to be rotatable with respect to said support member (2; 4) about said axis (2; 4) inserted between said support member (2; 4) and said pulley (3) and coupled to said pulley (3) And a spiral spring (6) comprising a sliding portion (16) which is resiliently loaded in a radial direction with respect to the sliding wall (10) supported by one of the pulleys The sliding portion 16 includes a first contact region 17 and a second contact region 17 in which the contact pressure exchanged between the sliding portion 16 and the sliding wall 10 is concentrated and at least one second contact region 19 ), The first and second contact areas (17; 18, 19; 66) are angled and spaced apart, The helical spring (6) comprises a support element (61) Characterized in that the sliding part (16) comprises at least one runner (17; 19) supported by the support element (61) and defining at least one of the first and second contact areas (17; 18, 19; 66) ≪ / RTI & The sliding portion 16 includes the supporting element 61, Characterized in that the pulley assembly comprises a runner (17) and a stop (21) as stop means for stopping the sliding of the sliding part (16) in the stop position relative to the sliding wall (10). The method according to claim 1, The sliding portion 16 includes a middle portion 67 inserted in a tangential direction between the first and second contact regions 17, 18, 19 and 66 at a radial distance from the sliding wall 10 Wherein the pulley assembly comprises a pulley assembly. 3. The method of claim 2, Wherein the first and second contact areas (17; 18, 19; 66) are spaced at an angle of between 150 and 210 degrees. The method of claim 3, Wherein the first and second contact areas (17; 18, 19; 66) are spaced apart such that the resultant force of contact pressure is minimized. delete delete The method according to claim 1, Characterized in that the runner (17; 19) comprises a cover wall (29; 35) radially inserted between the support element (61) and the sliding wall (10). 8. The method of claim 7, The sliding portion 16 provides a back 63 with a generation line having a concave central segment, Characterized in that said cover wall (29; 35) forms a convex surface (32; 36) formed to engage said concave central segment. 9. The method of claim 8, The runner 17 comprises a pair of reliefs 17,19 which delimit the convex surface 32,36 in a direction parallel to the axis A and receive the side edge 64 of the support element 61 43). ≪ / RTI > The method according to claim 1, Characterized in that the runners (17; 19) are connected to the support element (61) by shape coupling acting in a tangential direction. The method according to claim 1, Characterized in that the runner (17; 19) comprises a metallic structure anchoring portion (27) and a head portion (28). 8. The method of claim 7, Characterized in that the runner (17; 19) is molded together with the support element (61). 8. The method of claim 7, Wherein the runner (17; 19) is connected to the support element (61) by an adhesive layer. The method according to claim 1, Characterized in that the runner (17; 19) comprises a pair of walls (30; 37) covering each side (62) of the support element (61). 12. The method of claim 11, Wherein the runner (17; 19) comprises a layer (34) arranged in contact with the sliding wall (10) and formed of a polymeric material, or a composite fiber reinforced polymeric matrix material or a friction material. 9. The method of claim 8, The spiral spring 6 includes a spiral portion 14 connected to the sliding portion 16, Characterized in that the cover wall (29; 35) of the runner (17; 19) provides an increasing radial thickness from the helical portion (14) towards the support element (61). delete The method according to claim 1, The support member comprises a hub (2) and a semi-mass mass (4) connected to the hub (2) Wherein the stop means comprises a wedge (23) and a chamfer (33) as damping means and wherein the chamfer (33) slides over an inclined plane (24) formed by the wedge (23) Induces an increase in the radial force exerted by the pulley (17) to reduce the speed of the pulley (3) relative to the hub (2) before the runner hits the stop. 19. The method of claim 18, The wedge 23 is provided on the sliding wall 10 to increase the radial load exerted by the sliding portion 16 before the hub 2 and the pulley 3 reach the rest position. And an inclined surface (24) supported by and cooperating with said sliding portion (16). The method according to claim 1, The stop device 21 includes first and second projections 25 projecting radially from the sliding wall 10 and defining a hole 26, The sliding portion 16 includes a head portion 28 that intersects the hole 26 to cooperate with the inclined surface 24 and a pair of opposing pairs of the head portion 28 and the head portion 28, And a proximal portion (31) of the pulley assembly. The method according to claim 1, Characterized in that the sliding part (16) comprises a second runner (19) with a distance in the tangential direction at the runner (17). The method according to claim 1, Characterized in that the pulley assembly comprises a hub (2) adapted to be fixed to a rotating member and a semi-mass mass (4) connected to the hub (2) to form a dynamic torsional vibration damper. 23. The method of claim 22, Characterized in that said support member comprises said hub (2). 23. The method of claim 22, Characterized in that the support member comprises the semi-mass mass (4). The method according to claim 1, Characterized in that said helical spring (6) is rotatably coupled to said support member (2; 4) by friction.

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