WO2021098909A1

WO2021098909A1 - Rocker pin for a rocker pin pair of a plate link chain

Info

Publication number: WO2021098909A1
Application number: PCT/DE2020/100942
Authority: WO
Inventors: Andreas GÖTZ
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2019-11-22
Filing date: 2020-11-04
Publication date: 2021-05-27

Abstract

The invention relates to a rocker pin (1, 2) for a rocker pin pair (3) of a plate link chain (4), having: - a length extension (5); - a height extension (7); - a width extension (9); - a plate contact surface (11, 12) for contact with a plate (13) during use in a plate link chain (4); - a rolling surface (14, 15) for contact with an additional rocker pin (2, 1) during use in a rocker pin pair (3); and - an end face (16, 17) on both sides which is oriented transversely relative to the length extension (5), wherein an angle having a rotation axis parallel to the radial direction (8) is designated as an azimuthal angle (18, 19), wherein, in the case of an azimuthal angle (18, 19) of zero, the length extension (5) is perpendicular to the corresponding end face (16, 17) and at an azimuthal angle (18, 19) of greater than zero, the corresponding end face (16, 17) the extension in the axial direction (6) of the rolling surface (14) is shorter than that of the plate contact surface (11). The rocker pin (1, 2) is characterized in particular in that the end faces (16, 17) of the rocker pin (1, 2) have an azimuthal angle (18, 19) not equal to zero. According to the invention, a further reduction of noise emissions is achieved by means of the proposed rocker pin, wherein merely a small or no increase in load of the friction contact with the bevel washer pairs is caused.

Description

Rocker pressure piece for a rocker pressure piece pair of a link chain The invention relates to a rocker pressure piece for a rocker pressure piece pair of a link chain, comprising:

- a length extension;

- a height extension;

- an extension of the width; - A tab contact surface for contact with a tab in use in a

Link chain;

- A rolling surface for contact with a further rocker pressure piece in use in a rocker pressure piece pair; and

- on both sides an end face which is oriented transversely to the length extension, an angle with an axis of rotation parallel to the radial direction as

Azimuthal angle is referred to, with an azimuthal angle of zero the length extension being perpendicular to the corresponding end face and with an azimuthal angle greater than zero the corresponding end face, the extension in the axial direction of the rolling surface is shorter than that of the plate contact surface. The rocker pressure piece is primarily characterized in that the end faces of the rocker pressure piece have an azimuthal angle other than zero. The invention further relates to a rocker pressure piece pair with such a rocker pressure piece, a link chain with such a rocker pressure piece pair, a belt drive with such, and a drive train with such a belt drive.

From the prior art rocker pressure pieces for a rocker pressure piece pair of a link chain are known as belt means for belt transmissions, for example a so-called CVT [continuous variable transmission], as traction means. Such a CVT is known, for example, from DE 100 17005 A1. Such Link chain is set up for the transmission of high torques and high speeds, as they are known, for example, from engine construction for motor vehicles. Because the gear noises are unusual and are generally perceived as annoying, it is a constant challenge to create a plate-link chain that emits as little noise as possible. At the same time, however, a long service life of the link chain, freedom of exchange as possible over the service life of a motor vehicle, and a high degree of efficiency are sought. Furthermore, the aim is to achieve the smallest possible effective circles (i.e. diameters effective for the transmission) on the conical pulley pairs of a belt drive, so that a large transmission ratio can be achieved in a small (radial) installation space. A link chain with rocker pressure pieces is known, for example, from WO 2016/095913 A1.

So far, attempts have been made to keep the vibration excitation as low as possible using different pitch lengths (implemented using two different tabs) and their sequence. These measures have already been exhausted to the maximum and further changes promise little further potential. It was found that the acoustic behavior could in principle be positively influenced if the impact impulses of the rocker pressure pieces on the conical disks could be made softer. However, the high load on the chain requires the rocker pressure pieces to be adequately dimensioned, that is, the rocker pressure pieces must be very rigid.

Proceeding from this, the present invention is based on the object of at least partially overcoming the disadvantages known from the prior art. The features according to the invention emerge from the independent claims, for which advantageous configurations are shown in the dependent claims. The features of the claims can be combined in any technically meaningful manner, with the explanations from the following also in this regard Description and features from the figures can be used, which include supplementary embodiments of the invention.

The invention relates to a rocker pressure piece for a rocker pressure piece pair of a link chain

- a length extension which is aligned in the axial direction in use in a link chain;

- a vertical extension which is aligned in the radial direction in use in a link chain;

- A width extension which, in use in a link chain, is aligned in the chain running direction;

- A plate contact surface for contact with a plate in use in a plate link chain;

- on both sides an end face which is oriented transversely to the longitudinal extension, an angle with an axis of rotation parallel to the radial direction being referred to as the azimuthal angle, with an azimuthal angle of zero the longitudinal extension being perpendicular to the corresponding end face and with an azimuthal angle greater than zero the corresponding one End face, the extension in the axial direction of the rolling surface is shorter than that of the plate contact surface.

The rocker pressure piece is primarily characterized in that the end faces of the rocker pressure piece have an azimuthal angle other than zero.

In the following, reference is made to the directions in space mentioned if the chain running direction, axial direction or radial direction and corresponding terms are used without explicitly indicating otherwise. Ordinal numbers used in the preceding and following description are used unless explicitly stated the contrary is pointed out, only for the sake of clear distinctness and do not reflect any order or ranking of the components identified. An ordinal number greater than one does not necessarily mean that another such component must be present.

The rocker pressure piece proposed here can be used in a rocker pressure piece pair with another rocker pressure piece. The two rocker pressure pieces of a rocker pressure piece pair are each in force-transmitting contact with their rolling surface and, when used in a link chain, their plate contact surfaces are in force-transmitting contact with one (other) associated plate. For this purpose, a rocker pressure piece has a longitudinal extent which, in use, is parallel to the axial direction. The axial direction is defined as a direction parallel to the axes of rotation of the cone pulley pairs. The link plates of a link chain are suspended adjacent to one another in the axial direction on the rocker pressure piece pair or the majority of the rocker pressure piece pairs of the link chain. Furthermore, the rocker pressure piece has a vertical extent which is parallel to the radial direction. The radial direction is defined on the looping circle formed by a link chain, this shape being usually oval in use, i.e. two centers (with the axes of rotation of the conical pulley pairs) are formed, which are connected by a center line. The radial direction is defined as positive, starting from the center line (within the circle of wrap) and running outwards (to the outside of the circle of wrap). Inside the circle of wrap is referred to here as radially inside and outside of the circle of wrap is referred to here accordingly as radially outside. The third spatial direction is the running direction of the chain, which in use therefore depends on the location in the looping circle and thus the three spatial directions mentioned here are to be regarded as a co-moving coordinate system. The width of the rocker pressure piece is parallel to the chain running direction. In a preferred embodiment, a rocker pressure piece has an oval, approximately teardrop-shaped, cross section (with the axial direction as the normal), the rocker pressure piece being narrow radially on the inside and is wider radially on the outside. The height extension is defined as the maximum extension in the radial direction and the width extension as the maximum extension in the chain running direction (in a straight section of the link chain, i.e. in use in the ideally tensioned strand).

At the end, that is to say in a view in the axial direction, an end face is provided in each case, which is set up in force-transmitting, preferably frictional, contact with the corresponding (conical) surface of the conical pulley pairs. The angle of inclination of the end face around the chain running direction is referred to as the radial angle. A radial angle is zero in the case of an end face which is aligned parallel to that of the (imaginary) radial-axial plane (spanned by the radial direction and the axial direction). Here a radial angle is defined between (radially outside of the rocker pressure piece) the radial direction and the respective end face and is greater with increasing inclination of the end face towards the (imaginary) longitudinal-axial plane (spanned by the chain running direction and the axial direction). The azimuthal angle is the angle of an inclination of the end face about the radial direction, that is to say an inclination in the chain running direction. An azimuthal angle is defined to the (imaginary) longitudinal-radial plane (spanned by the chain running direction and the radial direction) and zero if the end face in question lies in this longitudinal-radial plane. The azimuthal angle is defined as positive here if the tab contact surface is longer than the rolling surface of the rocker pressure piece. In the case of a positive azimuthal angle, the end face in the chain running direction (viewed from a center of the rocker pressure piece) points axially outwards. In one embodiment, the end faces are designed conventionally with regard to their radial angle, their extent and their edge shape, these (and possibly further) properties being superimposed by the azimuthal angle proposed here.

Here it is now proposed that the azimuthal angle of the end faces of the rocker pressure piece is not equal to zero. One edge of the (respective) end face is thus with the corresponding surface of the conical pulley pair is in stronger contact and a bending of the rocker pressure piece is caused beyond a pure axial compression. With the same load-bearing capacity, i.e. with the same modulus of elasticity and unchanged (height-width) cross-section, the cradle pressure piece is softer in engagement with the corresponding surface of the conical pulley pair.

In one embodiment, in a rocker pressure piece pair, one rocker pressure piece is designed according to the aforementioned embodiment and the other rocker pressure piece is different, for example designed conventionally. Both rocker pressure pieces are preferably designed as described above, particularly preferably with the axially protruding edge of the end faces in front of the chain running direction, i.e. in opposite directions positive (greater than zero) for the front rocker pressure piece and negative (less than zero) for the rear rocker pressure piece.

In a preferred embodiment, the end faces or their azimuthal angles are set up according to the average or minimum pressing force between the conical disk pairs so that the end face is in force-transmitting contact over a large area with the corresponding surface of the conical disk pair as a result of the bending of the respective rocker pressure piece, preferably both rocker pressure pieces of a rocker pressure piece pair.

According to a further aspect, a rocker pressure piece pair for a link chain of a belt drive is proposed, comprising two rocker pressure pieces according to an embodiment according to the above description, wherein the azimuthal angle of the front rocker pressure piece is greater than zero and the azimuthal angle of the rear rocker pressure piece is less than zero. In an alternative embodiment, the azimuthal angle of the rear rocker pressure piece is greater than zero and the azimuthal angle of the front rocker pressure piece is less than zero. The rocker pressure piece pair comprises two rocker pressure pieces, which are designed as described above. The rocker pressure pieces of the rocker pressure piece pair are each designed with an azimuthal angle not equal to zero. In a radial top view, the inclinations of the end faces of the two rocker pressure pieces of the rocker pressure piece pair are aligned parallel to one another on each of the two sides. Because the rocker pressure pieces of the rocker pressure piece pair are in force-transmitting contact with each other with their respective rolling surface in use in a belt drive, the azimuthal angles (in separate consideration) of the rocker pressure pieces are opposite to one another. In the (preferred) embodiment proposed here, the front plate contact surface, i.e. the plate contact surface of the front rocker pressure piece in the chain running direction, is longer than the front rolling surface, i.e. the rolling surface of the front rocking pressure piece in the chain running direction. But the rear rolling surface, i.e. the rear rolling surface of the rear rocker pressure piece in the chain running direction, is longer than the rear plate contact surface, i.e. the plate contact surface of the rear rocker pressure piece in the chain running direction.

It is also proposed in an advantageous embodiment of the rocker pressure piece pair that the expansion in the axial direction of the front strap contact surface corresponds to that of the rear rolling surface; and / or the extension in the axial direction of the rear plate contact surface corresponds to that of the front rolling surface.

In this embodiment, the front plate contact surface has the same axial extent as the rear rolling surface and / or the front rolling surface has the same axial extent as the rear plate contact surface. In this way, the same compression and bending can be achieved in use and the axial softness of the rocker pressure piece pair is increased, while at the same time ensuring that a force-transmitting contact of the two rolling surfaces of the rocker pressure pieces of the rocker pressure piece pair is not counteracted by the tab load be generated. The rocker pressure pieces are therefore not forced away from one another as a result of the (elastic) deformation caused by the pressing force.

According to a further aspect, a link chain for a belt drive is proposed, having a plurality of link plates and a corresponding number of rocker pressure piece pairs according to an embodiment according to the above description, wherein a torque between a first cone pulley pair and a second cone pulley pair can be frictionally transmitted by means of the link chain preferably a transmission ratio between the conical pulley pairs is continuously variable.

The link chain proposed here is set up as a traction device for a belt drive, for example for a CVT. In the case of a belt drive, a link chain forms a loop section on the transmission shafts and two strands between them, one being a tension strand or a load strand and the other being a slack strand. The strands and the looping circle sections together form an (oval) looping circle, as explained above. As far as a circle of wrap is spoken of, this does not mean a circle with a constant radius, but a circumferentially closed structure. The shape is defined by the effective circles (set by means of a pulley spacing) of the conical pulley pairs of the belt drive. The spatial directions are also defined here as explained above.

The link chain has a chain width and over this chain width a plurality of link plates are generally arranged adjacent to one another and form a link plate group. In use, the chain width is aligned parallel to the alignment of the at least two transmission shafts. The chain width is defined by the width of the rocker pressure pieces, with the (axial) ends of the Rocker pressure pieces protrude beyond the adjacent tabs so that the tabs do not come into frictional contact with the corresponding surface of the conical pulley pairs.

The link chain comprises a plurality of link plates, a plurality of link plate types, for example two link plate types, namely a short link plate and a long link plate, preferably for a (as explained above) reduced noise emission. The tabs each contain two pairs of rocker pressure pieces. A rocker pressure piece pair has a fixed rocker pressure piece and a free rocker pressure piece in relation to a bracket. Two tabs are each connected to one another by means of a common pair of rocker pressure pieces in a manner that transmits tensile force, the designation as free or fixed rocker pressure piece then being reversed in each case for the other tab. The two rocker pressure pieces of a rocker pressure piece pair lie directly against each other in a force-transmitting manner due to the tensile force transmitted by the link plates of the link chain during operation of the belt drive and thus the link load acting on the rocker pressure piece pair (on both sides in the chain running direction). The two rocker pressure pieces of the rocker pressure piece pair transmit the tensile force of the tabs as a compressive force to each other and roll off each other during the movement in a belt transmission by means of their force-transmitting rolling surfaces lying against each other. The rolling surfaces are curved or kinked and thus describe a rocking movement on each other when the belt drive is in operation.

In the case of a CVT, for example, the end faces of the rocker pressure pieces are designed with a radial angle greater than zero in order to form an approximately parallel contact surface with the (inclined conical) surfaces of the conical pulley pairs.

In the case of a CVT, a torque is introduced into the plate-link chain as a tensile force via the end faces of the rocker pressure pieces. The rocker pressure pieces are therefore loaded on both sides with an axial pressing force. Transfer the tabs At least on the currently free, i.e. not axially compressed, rocker pressure pieces (at least of the load strand) the torque as tensile load on the respective associated rocker pressure pieces, for example the immediately adjacent rocker pressure piece. The rocker pressure pieces or rocker pressure piece pairs are therefore linked in a tensile force-transmitting manner by means of the multiplicity of tabs.

In a preferred embodiment, the link chain is set up as a belt for a continuously variable transmission and the end faces of the rocker pressure pieces of the link chain are in force-transmitting contact with the corresponding (conical) surfaces of the conical pulley pairs.

It is proposed here that the azimuthal angle of the rocker pressure pieces of the rocker pressure piece pairs is not equal to zero, preferably the front azimuthal angle (of the front rocker pressure piece) is greater than zero and the rear azimuthal angle (of the rear rocker pressure piece) is less than zero. In this way, when the pressing force is applied, an increased (azimuthal) bending of the rocker pressure piece pair is caused in addition to a pure (axial) upsetting and thus the softness of the rocker pressure piece pair is increased. With the increasing softness of the rocker pressure piece pairs, the noise emission is reduced because the impact pulse is reduced when entering a pair of conical pulleys. At the same time, however, the transferable tensile force remains almost the same as with a conventionally designed link chain with the same modulus of elasticity and cross-section. The link chain proposed here can be used as a replacement for a conventional link chain without additional measures.

According to a further aspect, a belt transmission for a drive train is proposed, having at least the following components:

- A first pair of conical disks of a first axis of rotation and with a variable axial first disk spacing;

- A second pair of conical disks with a second axis of rotation variable axial second disk spacing; and

- A plate-link chain according to an embodiment according to the above description, the two pairs of conical pulleys being connected to each other in a torque-transmitting manner by means of the plate-link chain, which is arranged as traction means axially pressed into a pair of conical pulleys in the direction of the widthwise extension, with a transmission ratio that is dependent on the set pulley spacings are, with the transmission ratio between the conical pulley pairs preferably being continuously variable.

The belt drive is set up for a drive train, for example a motor vehicle, and comprises at least one first pair of conical disks arranged on a first transmission shaft, for example the transmission input shaft, and a second conical disk pair arranged on a second transmission shaft, for example the transmission output shaft, as well as one for torque transmission between the conical disk pairs provided belt means, namely the link chain described above. A conical disk pair comprises two conical disks, which are aligned with corresponding (conical) surfaces and are axially movable relative to each other. In a preferred embodiment, the (first) conical disk, also referred to as a loose disk or movable disk, is displaceable (axially displaceable) along its axis of rotation and the (second) conical disk, also referred to as a fixed disk, is fixed (axially fixed) in the direction of the axis of rotation. This allows the respective disc spacing of the respective conical disc pair to be changed.

When the belt drive is in operation, the link chain is moved between an inner position (small or minimum effective circle) and an outer position (large or maximum effective circle) in a (based on) due to the (conical) surfaces of the two conical disks by means of a relative axial movement of the conical disks of a conical disk pair the respective Axis of rotation) shifted radial direction. The link chain thus runs on a variable effective circle, i.e. with a variable running radius. As a result, a different speed ratio and torque ratio can be set from one conical disk pair to the other conical disk pair, preferably continuously.

The belt drive proposed here has a link chain according to the above description, the rocker pressure pieces of the link chain generating a small impact pulse as a result of the azimuthal angle not equal to zero. This reduces the noise emission of the link chain when the belt drive is in operation, while at the same time (with otherwise unchanged parameters) almost the same tensile force, that is to say the same torque can be transmitted by means of the belt drive.

According to a further aspect, a drive train is proposed having at least the following components:

- at least one prime mover;

- at least one consumer; and

- A belt drive according to an embodiment according to the above description, wherein the at least one drive machine for torque transmission by means of the belt drive is connected to the at least one consumer with a variable ratio.

The drive train, for example of a motor vehicle used to propel it via at least one propulsion wheel (consumer), is set up to include one of one or a plurality of drive machines, for example an internal combustion engine and / or an electrical machine, provided and via its respective drive shaft, for example that is to say the combustion shaft and / or the rotor shaft to transmit torque output for use by a consumer as required, that is, taking into account the required speed and the required torque. One use is, for example, an electrical generator to provide electrical energy or the transmission of torque to a propulsion wheel of a motor vehicle for propulsion.

In order to transmit the torque in a targeted manner and / or by means of a gearbox with different ratios, the use of the belt transmission described above is particularly advantageous because the link chain enables a very high degree of torque transmission efficiency. The link chain proposed here also has particularly low noise emissions with a high transmittable torque.

The invention described above is explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way restricted by the purely schematic drawings, it being noted that the drawings are not dimensionally accurate and are not suitable for defining size relationships. It is shown in

1: a symmetrically loaded conventional rocker pressure piece with an azimuthal angle of zero;

2: a simplified cross section of a rocker pressure piece;

3: a conventional rocker pressure piece at the beginning of the running-in phase with an azimuthal angle of zero;

4: a pair of rocker pressure pieces at the beginning of the running-in phase with opposing azimuthal angles not equal to zero;

5: a pair of rocker pressure pieces under symmetrical loading with opposing azimuthal angles other than zero; and FIG. 6: a belt drive in a drive train. In Fig. 1, a symmetrically loaded (conventional)

Cradle pressure piece 30 is shown, which is loaded by a pressing force 31 applied to the left end face 16 and by a pressing force 31 applied to the right end face 17. This situation corresponds to the rocker pressure piece pair 3 that has (completely) run into a conical disk pair 21, 22 (see FIG. 6). In this simplified embodiment, for a simplified view, the vertical axis of symmetry 32 as shown here and the horizontal neutral axis 33 intersect in the center of gravity of the conventional rocker pressure piece 30. A Cartesian coordinate system points in the vertical direction in the chain running direction 10 (named according to the application) and in the horizontal direction in the axial direction 6 and is in use parallel to the axes of rotation 24, 25 of the belt transmission 20 (see FIG. 6). The radial direction 8 is perpendicular to the image plane. The conventional rocker pressure piece 30 has an initial length 34 with a length extension 5 in the axial direction 6. The width extension 9 is aligned in the chain running direction 10. In addition, the conventional rocker pressure piece 30 has a front plate contact surface 11 (or a rear plate contact surface 12) and a front rolling surface 14 (or a rear rolling surface 15). The tab contact surface 11, 12 is set up for the (pressure) force-transmitting contact with a tab 13 (see FIG. 6). The rolling surface 14, 15 is set up for a (pressure) force-transmitting contact with a rolling surface 15, 14 of another rocker pressure piece. The loading length 35 describes the length of the conventional rocker pressure piece 30 which the conventional rocker pressure piece 30 assumes (elastically) as a result of the axially applied pressing forces 31. The pressing forces 31 act in this model (as averaging of the surface pressure) in the center of gravity of the end faces 16, 17 of the conventional rocker pressure piece 30.

The elastically deformed conventional rocker pressure piece 30 is shown with a solid line (load length 35) and in the unloaded starting position with a dashed line (starting length 34). The elastic deformation of the conventional The rocker pressure piece 30 can be determined with the following model calculation (for the cross-sectional area, see Fig. 2):

(1)

Here, Δl _lin corresponds to the difference between l (load _{length 35) and l 0} (unloaded initial length 34) of the (conventional) rocker pressure piece 30. F is the pressing force 31, E is the modulus of elasticity [given in mega-Pascal], w is the width extension 9 and h the height extension 7 [units of length given in millimeters], with

(1.a) l ₀ = 24mm,

(1, b) h = 5 mm,

(1, c) w = 1.8 mm, as well as

(1.d) E = 210,000 MPa and (1.e) F = 1000 N results for Δl _lin 12.8 μm [twelve and eight tenths of a micrometer],

In FIG. 2, a simplified cross-section of the (right) end face 17 of a rocker pressure piece 1, 2, 30 is shown for the model observation, the right end face 17 and the left end face 16 being identical. The Cartesian coordinate system is arranged in the center of gravity in this cross section of the rocker pressure piece 1, 2, 30. According to FIG. 1, the radial direction 8 in the illustration points horizontally to the left (for the left end face 16 to the right), the chain running direction 10 vertically above and the axial direction 6 points out of the image plane (for the left end face 16 in). The vertical extension 7 of the rocker pressure piece 1, 2, 30, which is oriented in the radial direction 8, can also be seen here. As described with reference to FIG. 1, the widthwise extension 9 is aligned in the chain running direction 10. The axially acting pressing force 31 acts, as described in FIG. 1, on the end face 16, 17 (according to the model in the centroid of the area) and acts in the plane of the image. It should be pointed out that the end faces 16, 17 do not lie in the plane of the sheet and a rocker pressure piece 1, 2, 30 is always approximately teardrop-shaped.

FIG. 3 shows the conventional rocker pressure element 30 according to FIG. 1, which is loaded by a pressing force 31 applied to the left end face 16 and by a pressing force 31 applied to the right end face 17. In contrast to the loading situation according to FIG. 1, the axial pressing forces 31 do not act in the center of gravity in this model consideration. Rather, the point of application of the pressing force 31 is at the corner from the respective end face 16, 17 to the front plate contact surface 11 or to the rear rolling surface 15. This load situation corresponds (neglecting other geometrically determined consequences from the pressing force and the chain load) to the situation at the beginning the run-in phase of a conventional rocker pressure piece 30 in a pair of conical disks 21, 22 (see FIG. 6). At the point of intersection of the axis of symmetry 32 and the neutral axis 33 of the conventional rocker pressure piece 30 in the starting position (dashed illustration), the coordinate system that has already been defined is shown. The loading length 35 describes the length of the rocker pressure piece 30 which the rocker pressure piece 30 assumes due to the axially occurring pressing forces 31. In contrast to the load case according to FIG. 1, the pressing forces 31 do not act in the center of gravity, so that the rocker pressure piece 30 is bent in the plane of the sheet (i.e. in the plane spanned by the chain running direction 10 and the axial direction 6). This deformation leads to an inclination of the end faces 16, 17 by the deformation angle 36 (here, for the sake of clarity, only shown on the right end face 17). It should be noted that the deformation is exaggerated and shown in the model assumption a collision of the rear area of the conventional rocker pressure piece 30 with the contact surfaces of the conical disk pair 21,22 is excluded. The load length 35 is calculated as follows: and in summary with formula (1) where T is the bending moment with the pressing force at a distance from the neutral axis by half the width extension 9 [given in Newton meters] and tan (α) is the tangent of the angle α (Deformation angle 36) is. The tangent indicates the amount of (linear) deformation in the axial direction 6. This deformation, so the difference is .DELTA.l _azi thus resulting from the deformation angle 36 shortening the initial length 34. (1.a) With the values obtained according to (1.e) is an axial deformation .DELTA.l _ges of 51 microns [fifty micrometers],

4 shows a rocker pressure piece pair 3 with a front rocker pressure piece 1 and a rear rocker pressure piece 2, the spatial alignment corresponding to the coordinate system already shown in the preceding. The coordinate system is arranged in the starting position (dashed representation of the rocker pressure pieces 1, 2) in the plane between the rolling surfaces 14, 15. The cradle pressure piece pair 3 runs in the chain running direction 10 shown (vertically upwards as shown) into a conical disk pair 21,22, the first one entering as the front rocker pressure piece 1 and the second one being referred to as the rear rocker pressure piece 2. Here, in addition to the load with the pressing force 31, the one in use in a link chain 4 (see FIG. 6) in the chain running direction 10 from both sides on the respective link contact surface 11, 12 acting link load 37 shown. The link load 37 is shown here in a simplified form as a force acting centrally (along the axis of symmetry 32), but in use it corresponds to a sum of flatly distributed individual loads starting from one link 13. The link load 37 is so great during operation that the two rolling surfaces 14, 15 of the two rocker pressure pieces 1.2 cannot lift from one another. In contrast to a conventional rocker pressure piece 30 (see FIG. 1 or FIG. 3), the end faces 16, 17 are designed with an azimuthal angle 18, 19 not equal to zero. The front azimuthal angle 18 of the front rocker pressure piece 1 is greater than zero and the rear azimuthal angle 19 of the rear rocker pressure piece 2 is less than zero. Thus, in the front rocker pressure piece 1, the (front) tab contact surface 11 is longer than the (front) rolling surface 14. In the rear rocker pressure piece 2, the (rear) tab contact surface 12 is shorter than the (rear) rolling surface 15. The azimuthal angles 18, 19 of the rocker pressure pieces 1 , 2 of the rocker pressure piece pair 3 are therefore aligned in opposite directions.

The start of the running-in phase is shown here, as shown in FIG. 3. Here, only the front rocker pressure piece 1 (namely at the corner between the respective end face 16, 17 and the front plate contact surface 11) is loaded with the axial pressing force 31, because at the start of the run-in phase only the front rocker pressure piece 1 is in contact with the conical disk pairs 21 , 22 stands. As a result of the pressing force 31 and the azimuthal angle 18 of the (front) end faces 16, 17, the deformation (shown with a solid line) of the rocker pressure pieces 1, 2 results. At an azimuthal angle equal to zero, the rear rocker pressure piece 2 supports the front one and, due to the friction between the two rolling surfaces 14, 15, at least partially removes the deflection of the front rocker pressure piece 1 again. Thus, with the rear azimuthal angle 19 less than zero is the large difference .DELTA.l _ges (in the mentioned example of 51 microns) for the cradle thrust piece pair 3 can be achieved.

If, in addition, a radial angle is provided which is greater than the inclination of the pair of conical disks 21, 22, then due to the same formula, whereby the height effective in the area moment of inertia with the third power (times the height extension 7 and times the width extension 9) with the lever arm of the pressing force 31 and the lever arm of the deformation resulting from the deflection (the height in each case) cancels out (compare abbreviation of w ( Width extension 9) in formula (2.3)) for the total difference Δl tot _{+ rad} with the following formula:

(3) Δl tot _{+ rad} = Δl _lin + Δl _azi + Δl _rad = Δl _lin + 2. Δl _{azi achieved} a total difference (with radial angle) Al _{total + rad} of 89.2 μm.

This results in a greater deformation than in the embodiment according to FIG. 3. The rocker pressure piece pair 3 with a front rocker pressure piece 1 with an azimuthal angle 18 greater than zero is therefore less stiff and therefore quieter than a rocker pressure piece pair 3 with a conventional rocker pressure piece 30.

In Fig. 5 the rocker pressure piece pair 3 according to Fig. 4 is shown, but here in the (fully) run-in load situation in which both rocker pressure pieces 1, 2 in (pressure) force-transmitting contact with the cone pulley pairs 21, 22 (see Fig. 6) stand. While in a rocker pressure piece pair 3 with conventional rocker pressure pieces 30 the stiffness of the rocker pressure piece pair 3 is increased with the entry of the rear rocker pressure piece 2, in the embodiment shown with oppositely aligned azimuthal angles 18,19 of the end faces 16,17 of the front rocker pressure piece 1 and the rear rocker pressure piece 2 the bending of the front rocker pressure piece 1 is supported by the rear rocker pressure piece 2. That is, the rear rocker pressure piece 2 neither remains straight nor is it bent in the opposite direction. Rather, the front rocker pressure piece 1 and the rear rocker pressure piece 2 are bent in the same way, preferably with the same amount as shown here (and in the same direction). In the one shown In the embodiment, the loading length 35 of the rocker pressure piece pair 3 corresponds approximately to the loading length 35 of the front rocker pressure piece 1.

In FIG. 6, a belt transmission 20 is shown in a perspective view in a section of a drive train 23, in which a link chain 4 runs as a traction means on two pairs of conical pulleys 21, 22. The link chain 4 has a chain width in the axial direction 6 (parallel to the axis of rotation) which corresponds to the length extension 5 of the rocker pressure piece pair 3. Thus, a defined disk spacing 26, 27 leads to a resulting effective circle on the respective pair of conical disks 21, 22. In this case, the first disk spacing 26 is large and thus the first effective circle is small and the second disk spacing 27 is small and the second effective circle is thus large. A torque ratio greater than 1, for example 2, is thus set by means of the belt transmission 20 from a first gear shaft 38, for example a gear input shaft, with a first axis of rotation 24, to a second gear shaft 39, for example a gear output shaft, with a second axis of rotation 25.

The tabs 13 are linked to one another (for the transmission of tensile force in the strands 40, 41) to form a ring by means of the multiplicity of rocker pressure piece pairs 3. A plurality of tabs 13 are arranged next to one another in the axial direction 6. A coordinate system is shown here in the first strand 40, which corresponds to the coordinate system according to the preceding figures. The chain running direction 10 lies in the plane of the ring of the link chain 4. The axial direction 6 (corresponds to the direction of the chain width) is aligned parallel to the axes of rotation 24, 25. The radial direction 8 points to the outside of the ring formed by the link chain 4. The position of the coordinate system shown is defined at any point on the plate link chain 4 and the alignment of the chain running direction 10 and the radial direction 8 as well as the position of the axial direction 6 changes with the movement of the plate link chain 4. For example, a drive machine 28 is connected to the first transmission shaft 38, only the torque-absorbing input gear being shown here. For example, a consumer 29, for example at least one drive wheel for a motor vehicle, is connected to the second transmission shaft 39, only the torque-emitting output gear being shown here.

A further reduction in the noise emission is achieved here by means of the proposed rocker pressure piece, with only a slight or no increase in the load on the frictional contact with the conical disk pairs being caused.

LIST OF REFERENCE SYMBOLS front rocker pressure piece 29 consumer rear rocker pressure piece 30 conventional rocker pressure piece rocker pressure piece pair 31 pressing force link plate chain 32 axis of symmetry length extension 33 neutral axis axial direction 34 starting length height extension 35 load length radial direction 36 deformation angle width extension 37 link load chain running direction 38 first shaft front link linkage 40 first strand gear surface 41 second strand linkage contact surface 39 second strand contact surface 39 front rolling surface rear rolling surface left end face right end face front azimuthal angle rear azimuthal angle belt drive first pair of conical disks second pair of conical disks drive train first axis of rotation second axis of rotation first distance between disks second distance between disks drive machine

Claims

1. Rocker pressure piece (1, 2) for a rocker pressure piece pair (3) of a link chain (4), having a length extension (5) which is aligned in the axial direction (6) in use in a link chain (4); a vertical extension (7) which, in use in a link chain (4), is aligned in the radial direction (8); a width extension (9) which, in use in a link chain (4), is aligned in the chain running direction (10); a plate contact surface (11, 12) for contact with a plate (13) in use in a plate-link chain (4); a rolling surface (14,15) for contact with a further rocker pressure piece (2,1) in use in a rocker pressure piece pair (3); and on both sides an end face (16, 17) which is oriented transversely to the length extension (5), an angle with an axis of rotation parallel to the radial direction (8) being referred to as an azimuthal angle (18,19), with an azimuthal angle (18 , 19) from zero the length extension (5) is perpendicular to the corresponding end face (16,17) and at an azimuthal angle (18,19) greater than zero the corresponding end face (16,17) the extension in the axial direction (6) of the rolling surface (14, 15) is shorter than that of the tab contact surface (11, 12), characterized in that the end faces (16, 17) of the rocker pressure piece (1, 2) have an azimuthal angle (18, 19) other than zero.

2. rocker pressure piece pair (3) for a link chain (4) of a belt drive (20), comprising two rocker pressure pieces (1,2) according to claim 1, wherein the azimuthal angle (18) of the front rocker pressure piece (1) is greater than zero and the azimuthal angle (19) of the rear rocker pressure piece (2) is less than zero.

Rocker pressure piece pair (3) according to claim 2, wherein the extension in the axial direction (6) of the front plate contact surface (11) corresponds to that of the rear rolling surface (15); and / or the extension in the axial direction (6) of the rear plate contact surface (12) corresponds to that of the front rolling surface (14).

Link chain (4) for a belt drive (20), having a plurality of link plates (13) and a corresponding number of

Rocker pressure piece pairs (3) according to claim 2 or 3, wherein by means of the link chain (4) a torque between a first

Conical disk pair (21) and a second conical disk pair (22) can be transmitted in a frictionally locking manner, a transmission ratio between the conical disk pairs (21, 22) preferably being continuously variable.

Belt drive (20) for a drive train (23), having at least the following components: a first pair of conical pulleys (21) of a first axis of rotation (24) and with a variable axial first pulley spacing (26); a second pair of conical disks (22) of a second axis of rotation (25) with a variable axial second disk spacing (27); and a plate-link chain (4) according to claim 4, wherein the two pairs of conical pulleys (21, 22) are arranged by means of the plate-link chain (4) as traction means axially pressed into a pair of conical pulleys (21, 22) in the direction of the widthwise extension (9), with a transmission ratio which is dependent on the set disk spacings (26, 27), transferring torque to one another are connected, the transmission ratio between the conical disk pairs (21, 22) preferably being continuously variable. 6. Drive train (23), comprising at least the following components: at least one drive machine (28); at least one consumer (29); and a belt drive (20) according to claim 5, wherein the at least one drive machine (28) for torque transmission by means of the belt drive (20) with the at least one

Consumer (29) is connected to changeable translation.