JPS61160645A - Endless belt for power transmission - Google Patents

Abstract

PURPOSE:To improve durability, by utilizing the character of a hoop, which moves to a lower surface of curved line when small friction force is generated, and performing centering action. CONSTITUTION:A belt forms an endless carrier passing surface 36b of a power transmitting block 34 in a recessed curved surface while a hoop 32a, 32b,... 32n, forming an endless carrier 32, curving its width direction sectional shape to a direction of the recessed curved surface of the endless carrier passing surface 36b. And a radius R1 of the recessed curved surface of the endless carrier passing surface 36b and a radius R2 of the hoop width direction sectional curved shape form a relation where R1>R2, further a laminated surface of the hoop 32a, 32b,... 32n is formed to a sliding surface of low friction coefficient.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an endless belt for power transmission used in a belt-type continuously variable transmission.

[Conventional technology]

Recently, belt-type continuously variable transmissions have been proposed as transmissions for vehicles such as automobiles.

A belt-type continuously variable transmission has a pulley having a circumferential groove with a V-shaped cross section on one rotating shaft and the other rotating shaft.
An endless belt for power transmission is attached to this boob. By changing the width of the circumferential groove of the V-shaped cross section of the pulley, rotational power is transmitted from one rotating shaft to the other rotating shaft in a stepless manner.

The endless belt for power transmission used in this belt type continuously variable transmission consists of an endless carrier and a power transmission block, and the power transmission blocks are arranged adjacent to each other in a daisy chain on the endless carrier.

Further, the power transmission block is disposed such that its endless carrier passage surface frictionally engages with the endless carrier.

The frictional engagement between the endless carrier passing surface of the power transmission block and the endless carrier is generally achieved by a centering action (for example,
No. 47158).

FIGS. 5 and 6 show a conventional general structure in which the centering action is performed.

As shown in FIG. 5, the endless carrier passage surface 36b of the power transmission block 34 is formed (crowned) into a convex curved surface with a radius R, and the endless carrier passage surface 36b of the convex curved surface is 32 are frictionally engaged.

The endless carrier 32 includes a plurality of band-shaped hoops 32a,
32b, . . . 32n are stacked. These hoops 32a, 32b, -----
-32n, as shown in Fig. 6, is usually made of a thin flat plate of maraging steel, and the back side χ of the laminated surface is surface profiled (Japanese Patent Laid-Open No.
5--103133), each hoop 32a
, 32b, . . . 32n, and between the innermost hoop 32a and the endless carrier passage surface 36b.

In this way, the endless carrier passing surface 36b is formed into a convex curved surface, and between the endless carrier passing surface 36b and the innermost hoop 32a, and each of the hoops 32a, 32b, .
---32n, each hoop 32a, 32b, ---32n has an endless carrier passing surface 36b formed in a convex curved surface, as is well known.
A so-called centering action is performed to find the highest point.

[Problem that the invention seeks to solve]

However, the above-mentioned centering action does not occur between the endless carrier passing surface 36b and the innermost hoop 32a, and between each hoop 3
This is normally performed when the frictional force between the hoops 32a, 32b, =-.
--32n is shifted to the lower side of one of the convex curved surfaces of the endless carrier passage surface 36b.

Therefore, in order to ensure this frictional force, conventionally, as shown in FIG.
The back surface χ of the laminated surface of 32n is subjected to surface profiling, but after long-term use, the surface profiled back surface χ may wear out and become mirror-like.

As a result, the friction coefficient decreases, the frictional force becomes less than a predetermined value, and a problem may occur in which the centering action is no longer performed.

In this way, the hoops 32 a, 32 b, ----
-32n no longer has a centering effect and begins to slide down the convex curved surface of the endless carrier passage surface 36b, the hoops 32a, 32b, -32n
The side end surfaces of the bearings may come into contact with other parts such as the pulley surface, accelerating wear and reducing durability.

Therefore, the problem to be solved by the present invention is that the centering action is reliably performed even after long-term use.
The objective is to improve the durability of endless belts for power transmission.

[Means for solving problems]

The present invention aims to solve the above-mentioned problems by performing a centering action by utilizing the property that the hoop moves toward the lower side of the curved surface when the frictional force is low.

Specifically, the present invention provides the aforementioned endless belt for power transmission, in which the endless carrier passing surface of the power transmission block is formed into a concave curved surface, and the width direction cross section of the hoop forming the endless carrier is formed into a concave curved surface. The shape is curved in the direction of the concave curved surface of the endless carrier passing surface, and the radius R1 of the concave curved surface of the endless carrier passing surface and the radius R2 of the curved shape of the cross section of the hoop in the width direction are R,>R , and the laminated surface of the hoop is formed into a sliding surface with a low coefficient of friction.

[Effect]

According to the above-mentioned means, since the laminated surface of each hoop is formed as a sliding surface with a low coefficient of friction, the frictional force between the endless carrier passing surface of the power transmission block and the innermost hoop and between each hoop is reduced. is very small, and each hoop performs a centering action to find the lowest point of the curved surface.

This centering action is achieved by the fact that the endless carrier passing surface of the power transmission block is formed into a concave curved surface, and the cross-sectional shape of the hoop in the width direction is also formed into a curved shape that follows the concave curved surface of the endless carrier passing surface, and Since the radius R1 of the concave curved surface of the endless carrier passage surface and the radius R2 of the curved shape of the hoop are R1>R, the hoop is located at the lowest point of the concave shape of the endless carrier passage surface of the power transmission block. This is done as the desired centering action.

Further, since the sliding surface of the laminated surface of each hoop with a low coefficient of friction hardly changes even after long-term use, the above-mentioned centering effect can be reliably performed even after long-term use. On the contrary, when the laminated surface of the hoop becomes a sliding surface with an even lower coefficient of friction due to wear of the sliding contact during long-term use, the centering action becomes more reliable.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is a schematic diagram showing an example of a continuously variable transmission in which the endless belt for power transmission according to the present invention is used.

To explain this FIG. 3, the drive source 1 such as an engine
A clutch 12 is connected to the clutch 1.
2 is connected to an input pulley 14. Input pulley 1
4 consists of a movable pulley 14a and a fixed boob IJ 14b. Both pulleys 14a and 14b are formed with an inclined pulley surface 16.16, and a circumferential groove with a ■-shaped cross section is formed in the input turn IJ14. are doing. This circumferential groove with a cross section of the letter square serves as a driving surface for the input pulley 14.

An output pulley 18 is arranged next to the large force pulley 14. This output pulley 18 also consists of a movable pulley 18a and a fixed pulley 18b.

Both pulleys 18a and 18b are provided with inclined pulley surfaces 20, 20 similar to the case of the input pulley 14, and a circumferential groove with a V-shaped cross section is formed in the output turn IJ18. This circumferential groove with a V-shaped cross section serves as a driven surface of the output pulley 18. 'Then, the pulley surface 1 of the large force pulley 14
The endless belt 30 for power transmission is passed between the circumferential groove of the V-shaped cross section formed by 6.16 and the circumferential groove of the V-shaped cross section formed by the pulley surface 20.20 of the output pulley 18. , rotational power is transmitted from the input pulley 14 to the output pulley 18.

Note that the width of the circumferential groove of each of the movable pulley 14a of the large force pulley 14 and the movable pulley 18a of the output pulley 18 is changed by means such as hydraulic pressure. By continuously changing the width of this circumferential groove, the rotation of the output pulley 18 is taken out in a stepless manner.

The continuously variable transmission shown in FIG. 3 has an endless belt 30 for power transmission.
The clutch is constructed by a combination of the input pulley 14 and the output pulley U18, and the rotational power from the drive source 10 is transmitted to the continuously variable transmission via the clutch 12, resulting in a continuously variable transmission. The speed is changed by the machine and taken out. The extracted rotational power is transmitted to the differential 24 via the reduction gear pair 22, and further transmitted from the differential 24 to the wheels 26 to drive the vehicle.

Figure 4 shows the input pulley 14 and output pulley 1 in Figure 3.
8 shows a side view of the state in which the power transmission endless belt 30 is hung. As can be seen from FIG. A plurality of power transmission blocks 34 are attached adjacent to each other in a daisy chain arrangement. In addition, the power transmission block 34 has a circumferential length of the endless power transmission belt 30 of 6.
In the case of about 2On+, 300 to 400 pieces are normally used.

FIG. 1 is a cross-sectional view showing the state in which - number of power transmission blocks 34 and endless carrier 32 are attached to the endless belt 30 for power transmission.

In FIG. 1, the power transmission block 34 is entirely made of metal, and the main body 36 of the power transmission block 34 is made of metal.
Both sides 36a, 36a are the pulley surface 16.16 of the input pulley 14 or the pulley surface 20.2 of the output pulley 1J18.
It is formed on an inclined surface that makes frictional contact with 0. Main body part 36
A neck portion 38 is provided to protrude upward from the center portion of the device, and a support portion 40 is integrally formed at the upper portion of the neck portion 38 .

Endless carrier engagement grooves 42, 42 are formed between the body portion 36 and the support portion 40 on both sides of the neck portion 38. The endless carrier engaging grooves 42.42 engage with the pair of endless carriers 32.32, and the power transmission block 34 is supported by the endless carriers 32.32. The upper surface of the main body portion 36 forming the endless carrier engagement grooves 42, 42 serves as endless carrier passing surfaces 36b, 36b, with which the endless carrier 32 is frictionally engaged. This endless carrier street surface 36
b is formed into a concave curved surface with a radius R1.

The endless carrier 32 is formed by stacking a plurality of ring-shaped hoops 32a, 32b, -32n. It is usually formed by laminating about 8 to 12 sheets. For convenience of illustration, FIG. 1 shows a case in which the number of laminated hoops is six. In addition, the size of one hoop is generally 0.2 fin thickness, 8 fi width, and 62 mm circumference.
It is about 0 mm. Moreover, each hoop 32a, 32b, -
----32n is made of a metal material such as maraging steel. Recently, it is sometimes made of resin.

Each hoop 32a, 32b, -=-32n has a curved cross-sectional shape in the width direction. This curved shape follows the concave curved surface formed on the endless carrier passage surface 36b of the power transmission block 34 described above, and its radius is R7. The radius R1 of the concave curved surface of the endless carrier passing surface 36b and the radius R3 of the curved shape in the width direction of the hoops 32a, 32b, . . . 32n are formed so that R,>R2. ing. For example, R1 is 300-600m, R2 is 150m
It is formed at ~200m.

Further, as shown in FIG. 2, hoops 32a, 32b, .
----The back side χ and front side y of the laminated surface of 32n are not subjected to surface brofiling as in the conventional case,
0 formed on the sliding surface with a low coefficient of friction by chemical polishing
For example, the roughness of the laminated surface is set to 0.3 μRz.

In this way, the hoops 32 a, 32 b, ----
Since the laminated surface of -32n is formed as a sliding surface with a low coefficient of friction, each hoop 32a, 32b, ・-
--- Frictional force between 32n and innermost hoop 32
a and the endless carrier passage surface 36b of the power transmission block 34
The frictional force between the two hoops 32a, 32b, 32n acts to move toward the lower side of the curved surface.

And hoops 32a, 32b, -------32
An endless carrier passage surface 36b of the power transmission block 34 with which the endless carrier 32 formed by stacking n is frictionally engaged.
Since it is formed into a concave curved surface, the centering action is performed by finding the lowest point of this concave curved surface. This centering effect is achieved because the radius R2 of the curved shape of the hoop 32a is smaller than the radius R1 of the concave curved surface of the endless carrier passing surface 36b.
The lowest part of the curved shape of the carrier 2a is in contact with the lowest part of the concave shape of the endless carrier passage surface 36b, so that an accurate centering action can be performed.

Furthermore, since the condition of the sliding surface with a low coefficient of friction on the laminated surfaces of the hoops 32a, 32b, -=-32n hardly changes even after long-term use, the centering action is reliable even after long-term use. done to.

〔Effect of the invention〕

As described in detail above, the present invention, contrary to the conventional art, forms a concave curved surface on the endless carrier passing surface of the power transmission block, forms the hoops constituting the endless carrier in a curved shape, and is formed on the sliding surface with a low friction coefficient,
It is designed to perform a centering action that seeks the lowest point, and this centering action maintains the sliding surface with a low coefficient of friction on the laminated surface of the hoop over a long period of time, so even after long-term use. It will definitely be done.

In this way, ensuring that the centering action is maintained over a long period of time increases the durability of the endless belt for power transmission by preventing the side end surfaces of the hoops from hitting other parts and causing damage as in the past. can be improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the endless belt for power transmission according to the present invention, FIG. 2 is a cutaway perspective view of a hoop, and FIG. A schematic diagram showing an example of a step-change transmission, Figure 4 is a side view extracted from Figure 3 with the endless belt for power transmission hanging and passing around, and Figure 5 shows a conventional endless belt for power transmission. cross section,
FIG. 6 is a cutaway perspective view showing a conventional hoop. Explanation of symbols 32...-1--Endless carriers 32a, 32b, ・----32n ・----
-Hoop 34--Power transmission block 36b-m--Endless carrier passage surface χ--Back side of laminated surface y--Surface of laminated surface Applicant Toyota Motor Corporation Figure 1 Figure 2 Figure 36 tl-μ, fllh K wri complete figure Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. Power transmission blocks are arranged adjacent to each other in a daisy chain on an endless carrier formed by stacking a plurality of band-shaped hoops, and the power transmission blocks are connected to the endless carrier passage surface. In the endless belt for power transmission, in which the endless carrier is disposed in frictional engagement with the endless carrier, the endless carrier passing surface of the power transmission block is formed into a concave curved surface, and the cross section in the width direction of the hoop forming the endless carrier The shape is curved in the direction of the concave curved surface of the endless carrier passing surface, and the radius R_1 of the concave curved surface of the endless carrier passing surface and the radius R_2 of the curved shape of the cross section of the hoop in the width direction are such that R_1>R_2. An endless belt for power transmission, characterized in that the laminated surface of the hoop is formed as a sliding surface with a low coefficient of friction.