JPS62155352A - Belt elements for cvt - Google Patents

Abstract

PURPOSE:To prevent the abrasion characteristic to the CVT (CONTINUOUSLY VARIABLE TRANSMISSION) forming a TiN or TiC coated layer onto the surfaces of the belt elements consisting of thin plates made of SC material. CONSTITUTION:The captioned belt for CVT is constituted by superposing a plurality (10-20 pieces) of the belt elements 1a, 1b,...1n consisting of thin metal plates made of SC material, precipitation hardened stainless steel or marageing steel in the direction of thickness and holding a number of metal blocks 5 in superposition in the longitudinal direction. The thickness of the thin metal plate is 0.1-0.2mm. The inner and outer peripheral surfaces and the both sides of each belt element 1a-1n are coated with titanium nitride or titanium carbide. Therefore, the abrasion which is characteristic for the CVT belt and generated by the relative slide between the belt elements and the slide between the belt elements and blocks can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a belt element for a CVT used in continuously variable transmissions of automobiles and the like.

[Conventional technology]

Continuously variable transmission, or CVT (continuously variable transmission) installed in automobiles
tiny variable transmls
A belt for power transmission, like the V-belt 1 illustrated in FIG. 1, is stretched between a pair of pulleys 2 and 3 to transmit power. As illustrated in FIG. 2, this type of belt 1 is constructed by laminating a plurality (approximately 10 to 20) of thin sheet metal belt elements 1a...1n (only some of which are shown) in the thickness direction. , a large number of metal blocks 5 are stacked and held in the longitudinal direction of the belt elements 1a, . . . , 1n, and power is transmitted through these metal blocks 5. The plate thickness of each belt element 1a...1n is about 0.1 to 0.2M. Examples of the shape of the metal block 5 are shown in FIGS. 3 to 5.

The aforementioned boos 92 and 3 each have a V-shaped groove similar to a general V-belt boob, and by changing the width of the groove by hydraulic control or the like, the rotation radius of the belt 1 is changed and both pulleys are The ratio of the rotational speeds of 2 and 3, that is, the gear ratio, is changed steplessly.

[Problem that the invention seeks to solve]

In the belt 1, when each belt element 1a...1n passes through the pulley 2.3, each belt element 1a...1n passes through the pulley 2.3.
-1n have different working radii from each other. On the other hand, the block 5 is substantially in point contact with its V-shaped inclined surfaces 5c, 5c on both sides, and the block 5 generally has a smaller radius of action than the belt elements 1a...1n.

Therefore, each belt element 1a...1n and block 5 are
According to mutually different working radii, each belt element 1a...
1n and the block 5 rotate together without relative slippage, but the circumferential speed is faster as the outer side of the block 5 moves. Therefore, when traveling on a straight line between pulleys 2 and 3, pulleys 2 and 3
Due to the circumferential speed difference that occurs when the belt rotates on the belt 1, each belt element 1a .

Thus, the contact portions between the block 5 and the belt elements 1a...1n are worn due to relative sliding, and in particular, the innermost belt element 1n is significantly worn due to the sliding with the block 5. Further, each of the belt elements 1a...1n also wears out due to relative slippage during straight running.

Furthermore, if the upper surface of the block 5, that is, the surface in contact with the innermost belt element 1n, is flat as shown in FIG. Contact with the neck portion 5a causes significant wear.

As mentioned above, the unique wear that occurs on CVT belts causes changes in the dimensions of the belt, leading to increased stress and decreased fatigue strength. Furthermore, wear of the belt elements induces fretting fatigue, which reduces fatigue life.

[Means for solving problems]

The present invention relates to a belt element made of a thin sheet metal selected from SC material, injection-hardened stainless steel, or maraging steel, wherein at least a portion of the surface thereof has T.
This is a CVT belt element characterized by being provided with a coating layer of iN (titanium nitride), TiC (titanium carbide), or a stack of TiN and Tic.

[Operation] A plurality of belt elements having the above structure are stacked to form a laminated belt, and metal blocks are arranged in the length direction of this laminated belt to form a V-belt.

When this V-belt runs on a straight line between the pulleys, relative slippage occurs between the belt elements and between the blocks and the belt element due to the circumferential speed difference generated when passing over the pulleys. However, the present invention uses TiN in the belt element.
Alternatively, since it is coated with TiC, it is possible to prevent wear and fretting fatigue caused by relative slippage that is characteristic of this type of belt. Furthermore, by preventing wear, it is extremely effective in suppressing dimensional changes and preventing increases in stress and decreases in fatigue strength.

〔Example〕

The CVT belt of this embodiment is made of approximately 10 to 20 thin metal belt elements 1a, similar to the above illustrated example.
, lb, lc...1n are laminated in the thickness direction, and a large number of metal blocks 5 are stacked and held in the length direction.

A V-shaped inclined surface 5C is formed on both sides of each block 5 and inscribed in the V-shaped groove of the pulley 2.3.

Examples of the shape of the metal block 5 are shown in FIGS. 3 to 5.

However, other shapes may be used.

The plate thickness of each belt element 1a...1n is approximately 0.1 to 0.2B. And belt elements 1a...1n
over the inner circumferential side, outer circumferential side, and both sides,
Coated with TiN (titanium nitride) or TiC (titanium carbide). The thickness of the coating layer is 0.5
Preferably it is between .mu. and 20.mu. If the coating layer exceeds 20μ, the rigidity becomes too high, and the coating layer is likely to peel off from the base layer or crack due to bending when passing over the pulleys 2 and 3. Moreover, if it is less than 0.5μ, the abrasion resistance effect decreases, making it unsuitable for practical use.

Further, preferably, the thickness of the coating layer of the belt element located on the inner layer side is made thicker than the coating layer of the belt element located on the outer layer side. in this case. Outermost layer belt element 1a
The thickness of each coating layer may be gradually increased one by one from 1 to the innermost belt element 1n, or a plurality of coating layers may be collectively formed to form a coating layer of the same thickness.

Further, according to research by the present inventors, among the stacked belt elements 11...1n, the innermost belt element 1
Since the number of belt elements from n to about 60% is particularly severely worn, only the number of belt elements corresponding to this region may be coated, and the outer layer side may not be coated at all.

In addition, in providing the above coating layer, the base +A-
If the coating layers are stacked in the order of Tic→TiN, the adhesive strength to the matrix H will be higher than when the TiN layer is directly coated on the matrix.

Suitable materials for the CVT belt element are thin metal plates made of SC material, injection-hardened stainless steel, or maraging steel.

〔Effect of the invention〕

According to the present invention, it is possible to prevent wear peculiar to CVT belts caused by relative slippage between belt elements or slippage between belt elements and blocks, and reduce fatigue life due to belt dimensional changes, fretting, etc. It has a great effect on prevention.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a transmission device using a CVT belt, Fig. 2 is a partial sectional view showing an example of a CVT belt, and Fig. 3 is a schematic diagram of a transmission device using a CVT belt.
Each of the figures through FIG. 5 is a front view showing an example of the shape of the metal block. 1 ・CV T belt, LA, LB, LC, in...
・Belt element, 2, 3...Pulley, 5...Metal block.

Claims (1)

[Claims] It is made of a thin sheet metal selected from SC material, injection hardening stainless steel, or maraging steel, and is characterized by having a coating layer of TiN, TiC, or a layer of these on at least a part of its surface. CVT belt element.