JPH0830516B2 - Block for transmission belt - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a block for a transmission belt used in a continuously variable transmission or the like.

[Conventional technology]

A belt for a continuously variable transmission used for a power transmission system of an automobile, a so-called CVT belt, is stretched between a drive side pulley 1 and a driven side pulley 2 as shown in FIG. An arbitrary gear ratio is obtained by changing the radius of the contact position between the belts 1, 2 and the belt 3. A conventional belt 3 of this type includes an endless carrier band 4 made of a thin metal plate having a multilayer structure, and a large number of metal blocks 5 stacked in the length direction of the carrier band 4,
Power is transmitted through these blocks 5.

As shown in an example in FIGS. 6 and 7, the conventional block 5 is composed of a block body portion 7 having a pair of left and right tapered surfaces 6, and a neck portion 8 and a head portion 9 connected to the block body portion 7. The carrier band 4 is adapted to come into contact with the band hanging surfaces 10 located on both the left and right sides of the neck portion 8.

Further, like the block for a transmission belt disclosed in JP-A-57-22441, the tapered surfaces on both sides of the block main body are concave so that the center in the plate thickness direction is depressed inward when viewed from the top surface direction of the block. It is also proposed that the contact area between the block and the pulley is increased by forming the shape.

[Problems to be solved by the invention]

In the above-mentioned conventional block 5 (FIG. 6), the left and right tapered surfaces 6 are in contact with the inclined surface 1a of the V-shaped groove of the pulley. For this reason,
As shown in FIG. 7, when traveling straight on the pulleys, the contact rolling distance 1 in the width direction with respect to the pulleys matches the width l ₁ of the block body. However, as exaggeratedly shown in FIG. 8, the block 5 has an angle θ in the front-rear direction when viewed from the upper surface direction (outer peripheral direction of the pulley).
When the vehicle travels on the pulley in a state in which it is tilted only (hereinafter, simply referred to as "tilt"), the distance l between the contact points with the pulley is
Is longer than the width l ₁ of the block 5. That is, when the plate thickness of the block 5 is t, As represented by, the contact point distance l to the pulley changes. The range of the inclination θ is 0 ≦ θ ≦ tan
^-1 (t / l ₁ ).

As described above, since the contact point distance l of the block 5 changes depending on the inclination, the radial position of the block 5 relative to the pulley is larger than the normal position depending on the inclination of the block 5 as shown by the chain double-dashed line in FIG. I will be lifted.
When the positions of the bricks 5 are thus uneven, the carrier band 4 does not follow one curvature on the pulley and is bent for each block 5. In this state, excessive stress is applied to the carrier band 4, which causes the durability of the carrier band 4 to decrease.

Further, the above-mentioned prior art (Japanese Patent Laid-Open No. 57-22441)
If the taper surface is dented as described above, the contact area with the pulley can be made large, but when the block is tilted, the contact point distance with the pulley also changes. Can not be solved.

From the viewpoint of considering the durability of the tapered surface (contact surface with the pulley), it has been conventionally considered to provide the tapered surface with a curved surface having a middle height in the thickness direction. However, conventionally,
Since no consideration was given to the above problem, that is, when the block moves on the pulley, the contact height of the block changes when the position of the left and right tapered surfaces shifts back and forth, The radius of curvature of the curved surface was not proper. In other words, the radius of curvature is too small or too large, and it is not effective to align the contact heights of the blocks when the blocks are tilted.

Therefore, it is an object of the present invention to suppress the fluctuation of the contact height of the block with respect to the pulley by preventing the contact point distance with the pulley from substantially changing even if the block tilts while the belt is running. .

[Means for solving problems]

To achieve the above object, the present invention provides a block main body 12 having a pair of left and right tapered surfaces 15 contacting the slopes of the V-shaped grooves of the pulleys 1 and 2 and a band hooking surface 16 on which the carrier band 4 slidably contacts. It is applied to the provided transmission belt block 11. And in the present invention, the pair of tapered surfaces
15 is formed in a curved shape such that the center in the plate thickness direction is convex outward when viewed from the top surface direction of the block 11, and the width of the block main body is l ₁ and the radius of curvature R ₁ of the tapered surface is , R ₁ = l _1/2 .

[Action]

In the block having the above structure, the tapered surfaces located on both sides of the block body contact the pulleys. Further, the carrier band passes on the band hanging surface of the block body, and the carrier band travels integrally with the block. However, the block and the carrier band can slide on each other.

When the belt runs, the block may tilt on the entrance side of the pulley or on the pulley. However, in the present invention, the tapered surface of the block body has a curved shape such that the center in the thickness direction thereof is convex outward, and even if the block is tilted, the tapered surface having a radius of curvature of half the block width is Because of the contact with the pulley, the contact point distance is constant or changes only slightly. Therefore, there is no problem that the height of each block changes on the pulley, and the carrier band bends on the pulley with a constant curvature. Therefore, it is possible to prevent the carrier band from being bent for each block and to prevent excessive stress from being applied to the carrier band.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. The belt block 11 of this embodiment is used in a state in which a large number of blocks 11 are stacked in the thickness direction as in the conventional case.
As the material of the block 11, cermet, ceramics or the like can be applied in addition to the iron-based metal. The carrier band 4 may be the same as the conventional one, and has a multi-layer structure in which a plurality of thin endless steel plates are stacked in the thickness direction. The block 11 can freely slide on the carrier band 4.

The block 11 includes a block main body 12, a neck 13 protruding from the block main body 12, and a head connected to the neck 13.
It is configured to be integrated with 14 and. Block body 12
A pair of left and right taper surfaces 15 contacting the sloped surface 1a of the V-shaped groove of the pulley are provided on both sides of. Also the block body 12
On the upper surface side in the figure, band hanging surfaces 16 are provided on both left and right sides of the neck portion 13. The carrier band 4 slidably contacts the band hanging surface 16. Block body 12
Is the taper start line 18 in its side view (Fig. 3).
The boundary is tapered so that the lower side is slightly tapered. With such a taper shape, it is possible to cope with the curvature when the block 11 passes through the pulleys 1 and 2.

Then, as shown in FIG. 2, a pair of left and right tapered surfaces
The block 15 is formed in a curved shape such that the center in the plate thickness direction is convex outward when viewed from the upper surface direction of the block 11 (outer peripheral side of the pulley). In the case of the present embodiment, the radius of curvature R ₁ of the tapered surface 15 is half the width l ₁ of the block body 12, that is,
R ₁ = l _1/2 .

More specifically, when the height from the bottom surface 12a of the block main body 12 is _H , the width of the block main body 12 at this height is l _H , and the radius of curvature of the tapered surface 15 at this height is R _H , R _H
The radius of curvature R _H changes according to the height H so that = l _H / 2. Therefore, the bottom surface 12a side has a smaller radius of curvature than the belt hanging surface 16 side.

Further, a protrusion 21 protruding in the thickness direction of the block 11 and a recess 22 located on the back surface side of the protrusion 21 are provided in the center of the head 14 in the width direction. The recess 22 is formed in such a size that the projection 21 of the block 11 located on the rear side thereof can be just fitted therein. The protrusion 21 and the depression 22 are not limited to the illustrated example. For example, the protrusion 21 and the depression 22 may be provided so as to be located on the taper start line 18, respectively. Further, the surface layer of the block 11 may be subjected to an appropriate surface treatment such as carburizing or nitriding treatment and TiC or TiN coating.

The transmission belt including the block 11 having the above configuration is stretched between the pulleys 1 and 2 as in the conventional belt. The left and right tapered surfaces 15 of the block body 12 are respectively in contact with the sloped surface 1a of the V-shaped groove of the pulley. Further, the carrier band 4 passes over the band hanging surface 16, and the carrier hand 4 is a pulley.
It travels with each block 11 as it rotates 1 and 2.

When the transmission belt runs, the block 11 may be inclined at the entrance side of the pulleys 1 and 2 or on the pulleys 1 and 2 as shown by the chain double-dashed line in FIG. However, even if such an inclination occurs, the tapered surface
15 is a curved surface with a radius R ₁ such that its center in the thickness direction is convex outward, and the radius of curvature R ₁ is the block width l ₁
The contact position with the pulley is on the same circumference. That is, the contact point distance l is the width l _{1 of the} block 11.
And is kept constant regardless of the tilt angle θ of the block 11. Therefore, there is no problem that the individual blocks 11 become uneven in height on the pulley, and the carrier band 4 bends on the pulley with a constant curvature. Therefore, the stress load on the carrier band 4 is reduced.

〔The invention's effect〕

According to the present invention, when the block travels on the pulley, the contact point distance between the block and the pulley can be kept substantially constant even if the left and right tapered surfaces are tilted such that the positions of the taper surface are displaced forward and backward. Since the contact heights of the blocks are uniform, the stress applied to the carrier band can be reduced, which is a great effect in improving the durability.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention, FIG. 1 is a front view of a block, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a side surface of the block. FIG. 4 is a perspective view of a part of the block, FIG. 5 is a side view conceptually showing the relationship between a belt and a pulley, and FIG. 6 is a front view of a conventional block.
FIG. 7 is a sectional view of the conventional block taken along the line VII-VII in FIG. 6, and FIG. 8 is a sectional view of the conventional block shown in FIG. 7 in a tilted state. 1,2 ... Pulley, 1a ... V-shaped groove slope, 4 ... Carrier band, 11 ... Block, 12 ... Block body, 13 ...
… Neck, 14 …… Head, 15 …… Tapered surface, 16 …… Band hanging surface.

Claims (2)

[Claims] 1. A transmission belt block comprising: a block main body having a pair of left and right taper surfaces contacting a slope of a V-shaped groove of a pulley and a band hanging surface on which a carrier band slidably contacts. The tapered surfaces are each formed in a curved shape such that the center in the plate thickness direction is convex outward when viewed from the top surface direction of the block, and the width of the block main body is l ₁ , the curvature of the tapered surface is A transmission belt block characterized in that when the radius is R ₁ , R ₁ = l _1/2 . 2. When the height from the bottom surface of the block body is H, the width of the block body at this height is l _H , and the radius of curvature of the tapered surface at this height is R _H , R _H = The transmission belt block according to claim (1), characterized in that the radius of curvature R _H is changed according to the height H so as to be l _H / 2.