PRESSURE PIECE WITH AN OPTIMISED THICKNESS RATIO, AND PLATE-LINK CHAIN COMPRISING A PRESSURE PIECE

Abstract

A pressure piece for articulated connection of links of a CVT plate-link chain for a drive train of a motor vehicle includes a center, a pressure piece lower portion with a lower thickness, a pressure piece upper portion with an upper thickness, and a thickness ratio between the lower thickness and the upper thickness. The lower thickness is measured at a predefined distance below the center when viewed in a vertical direction, and is measured perpendicular to the vertical direction. The upper thickness is measured at the predefined distance above the center when viewed in the vertical direction, and is measured perpendicular to the vertical direction. The thickness ratio is greater than 1/1.09.

Claims

1.-8.(canceled)

9. A pressure piece for articulated connection of links of a CVT plate-link chain for a drive train of a motor vehicle, comprising: a center; a pressure piece lower portion comprising a lower thickness, the lower thickness: measured at a predefined distance below the center when viewed in a vertical direction; and measured perpendicular to the vertical direction; a pressure piece upper portion comprising an upper thickness, the upper thickness: measured at the predefined distance above the center when viewed in the vertical direction; and measured perpendicular to the vertical direction; and a thickness ratio between the lower thickness and the upper thickness, wherein the thickness ratio is greater than 1/1.09.

10. The pressure piece of claim 9 further comprising a rolling surface aligned symmetrically to the center when viewed in the vertical direction.

11. The pressure piece of claim 10 further comprising: a contour line extending parallel to the vertical direction and through the center when viewed in the vertical direction; an upper angle enclosed between a rolling surface upper portion and the contour line; and a lower angle enclosed between a rolling surface lower portion and the contour line, wherein the pressure piece is aligned such that the upper angle and the lower angle are equal when the lower thickness and the upper thickness are measured.

12. The pressure piece of claim 9, wherein the thickness ratio is less than or equal to 1.

13. The pressure piece of claim 9 further comprising a total height when viewed in the vertical direction, wherein the predefined distance is 30% of the total height.

14. The pressure piece of claim 9, wherein a cross-section of the pressure piece is constant in a longitudinal extension of the pressure piece.

15. The pressure piece of claim 9, wherein the thickness ratio is between 1/1.05 and 1/1.09.

16. A CVT plate-link chain for a drive train of a motor vehicle, comprising: a plurality of the pressure pieces of claim 9 arranged in pressure piece pairs; a plurality of links, interconnected by the pressure piece pairs, wherein: each of the plurality of links comprises an outer longitudinal bracket, an inner longitudinal bracket, and a pair of transverse brackets; the pair of transverse brackets connects the outer longitudinal bracket to the inner longitudinal bracket to form a receiving opening; and a one of the pressure piece pairs is disposed in the receiving opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The disclosure is explained below with the aid of drawings. In the figures:

[0016] FIG. 1 shows a portion of an exemplary general embodiment of a plate-link chain, and

[0017] FIG. 2 shows a schematic cross-sectional view of a pressure piece of the plate-link chain.

DETAILED DESCRIPTION

[0018] The figures are only schematic in nature and serve only for understanding the disclosure. The same elements are provided with the same reference symbols.

[0019] FIG. 1 shows a portion of an exemplary general embodiment of a plate-link chain 1 for a drive train of a motor vehicle. The plate-link chain 1 may be used for a continuously variable transmission (CVT transmission). For example, the plate-link chain 1 serves as a traction means of a variator in order to connect two cone pulley pairs of the variator to one another. The plate-link chain 1 has a large number of links 2, which are referred to below as links 2. The links 2 are arranged to be parallel to a running direction of the plate-link chain 1. The links 2 are arranged in multiple rows which are arranged next to one another with respect to the running direction of the plate-link chain 1. The links 2 are articulated to one another via rocker pressure pieces 3, which are referred to below as pressure pieces 3. The pressure pieces 3 engage in openings 4 of the links 2 or reach through the openings 4 in order to connect them to one another. The pressure pieces 3 extend transversely to the running direction of the plate-link chain 1. The pressure pieces 3 extend over the entire width of the plate-link chain 1. The pressure pieces 3 connect adjacent straps 2 to one another transversely to the running direction.

[0020] The links 2 of one row are offset in the running direction of the plate-link chain 1 in relation to the links 2 of another row, so that the links 2 are connected to one another by the pressure pieces 3 in the running direction of the plate-link chain 1. The pressure pieces 3 are each arranged in pairs as a pressure piece pair 5. Each link 2 is connected by a first pair of pressure pieces to a link 2 located in front of it in the running direction (or to several links 2 located in front of it in the running direction). Each link 2 is connected by a second pair of pressure pieces to a link 2 located behind it in the running direction (or to several links 2 located behind it in the running direction).

[0021] In a non-bent state of the plate-link chain 1, the pressure pieces 3 of a pressure piece pair 5 rest against one another at a rolling point 6. The pressure pieces 3 of a pressure piece pair 5 roll against one another at the rolling point 6 when the plate-link chain 1 is guided over a radius and is thereby curved.

[0022] FIG. 2 shows a schematic illustration of the pressure piece 3 according to the disclosure. The design of the pressure piece 3 according to the disclosure is described in more detail with reference to FIG. 2.

[0023] According to the disclosure, a thickness ratio of the pressure piece 3 between a lower thickness 7 of a portion 8 of the pressure piece 3 which is lower in a vertical direction and an upper thickness 9 of a portion 10 of the pressure piece 3 that is higher in the vertical direction is greater than 1/1.09. The thicknesses 7, 9 are each measured at a predefined distance 11 from the center 12 of the pressure piece 3, seen in the vertical direction, and perpendicular to said vertical direction in a thickness direction of the pressure piece 3. The vertical direction corresponds to the direction in which the pressure piece 3 has a maximum extent. The maximum extent is measured, for example, in a symmetrical position of the pressure piece 3, which will be explained in more detail later. The thickness direction of the pressure piece 3 is perpendicular to the vertical direction. This means that the center 12 viewed in the vertical direction is at half a height 13 of a total extension 14 in said vertical direction/total height 14. The vertical direction runs parallel to a height contour 15, which is shown in FIG. 2. The thickness direction runs parallel to the line of the center 12, seen in the vertical direction, which is shown in FIG. 2.

[0024] This means that the upper thickness 9 is a maximum of 1.09 times as large as the lower thickness 7. The thickness ratio between the lower thickness 7 and the upper thickness 9 is less than or equal to 1/1. This means that the lower thickness 7 is smaller than the upper thickness 9. The thickness ratio (lower depth/upper depth) is therefore between 1/1.09 (˜0.9174) and 1. Since the extension in the thickness direction of the pressure piece 3 changes greatly over the vertical direction, the lower thickness 7 and the upper thickness 9 are each measured at the same distance from the center 12 as seen in the vertical direction. The thicknesses 7, 9 are measured, for example, in an area in which the thickness 7, 9 is approximately constant in an area remote from a contact area between the pressure piece 3 and the link 2, in the direction towards the center.

[0025] In the embodiment, the predefined distance 11 is less than 40% of the total height 14 of the pressure piece 3. For example, the predefined distance 11 may be 20% to 35% of the total height of the pressure piece 3. For example, the predefined distance may be approximately 30%±5%, e.g., exactly 30%, of the total height 14.

[0026] In the embodiment shown, the thickness ratio is less than 1/1.05. More precisely, the thickness ratio in the predefined distance 11 of 30% of the total height 14 is 1/1.071. This has proven to be suitable for loading the pressure piece 3.

[0027] In FIG. 2, a cross-section of the pressure piece 3 is shown. The cross-section of the pressure piece 3 is constant in a longitudinal extension of the pressure piece 3, i.e., perpendicular to the cross-section.

[0028] The pressure piece 3 has a rolling surface 16 with which it rests on another pressure piece 3, which forms a pressure piece pair 5 with the pressure piece (see FIG. 1). In this case, an upper angle α, which is enclosed between the rolling surface 16 of the upper portion 10 and the contour line 15, which runs through the center viewed in the vertical direction and is aligned parallel to said vertical direction, and a lower angle β, which is included between the rolling surface 16 of the lower portion 8 and the contour line 15, are formed. In FIG. 2, the pressure piece 3 is shown in a symmetrical position in which the upper angle α corresponds to the lower angle β. This means that the total height 14, the lower depth 7 and/or the upper depth 9 of the pressure piece 3 are measured in the symmetrical position in which the rolling surface 16 is aligned symmetrically to the center 12 viewed in the vertical direction.

REFERENCE NUMERALS

[0029] 1 Plate-link chain [0030] 2 Link [0031] 3 Pressure piece [0032] 4 Opening [0033] 5 Pair of pressure pieces [0034] 6 Rolling point [0035] 7 Lower thickness [0036] 8 Lower portion [0037] 9 Upper thickness [0038] 10 Upper portion [0039] 11 Predefined portion [0040] 12 Center [0041] 13 Half height [0042] 14 Total height [0043] 15 Contour line [0044] α upper angle [0045] β lower angle