JP2500287B2 - Continuously variable transmission system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission system in which a block belt for high load transmission is hung between a pair of variable pulleys.

[0002]

2. Description of the Related Art Conventionally, gears or fluid type transmissions have been widely used in automobiles or combine agricultural machines such as combine harvesters and tractors. Belt type continuously variable transmissions are being developed for the purpose of improving fuel efficiency. This continuously variable transmission is, for example, on a pair of rotating shafts arranged in parallel to each other, a fixed sheave fixed to the rotating shaft so as not to be slidable and slidable in the axial direction on the rotating shaft. A pair of variable pulleys each of which is supported by the movable sheave and has a movable sheave that forms a belt groove surface having a V-shaped cross section with the fixed sheave, and the V belt is wound between both variable pulleys. By changing the effective radius of each pulley with respect to the V belt by bringing the movable sheave into and out of contact with the fixed sheave facing each other, the gear ratio between both rotary shafts is made variable.

However, a belt used in a continuously variable transmission for automobiles called CVT, for example, requires an extremely high torque transmission capability, and a conventional general rubber V-belt cannot endure a high lateral pressure, and a seat is used. It cannot be used due to bending deformation.

In order to satisfy such demands, various types of high load transmission belts have been known (for example, Japanese Patent Application Laid-Open Nos. 46-4861 and 55-27595,
See JP-A-56-76745 and JP-A-59-77147.

Of these, a pair of endless tension bands, and a large number of blocks having fitting grooves for fitting the tension bands on the left and right side surfaces and an abutting portion for abutting the belt groove surface of the pulley are formed. Then, the concavo-convex portions that can be fitted to each other are formed on the upper and lower surfaces of the tension band and the upper and lower surfaces of the fitting portion of each block, and the tension band and the concavo-convex portion of each block are engaged to form the block. A proposal has also been made for a high load transmission belt called a block belt which is locked and fixed to the tension band in the longitudinal direction of the belt (JP-A-60-4).
9151, JP-A-61-206847, JP-A-62-54348).

[0006]

By the way, in this type of block belt, each block receives a pulley thrust related to a load that can be transmitted, and the abutting portions on the left and right sides of each block and the belt groove of the pulley. The dynamic friction coefficient with the surface (hereinafter, simply referred to as the friction coefficient) is usually set to a value of 0.3 or more from the viewpoint of enhancing the friction transmission capacity.

That is, in a CVT system for an automobile, it is required to be compact and lightweight due to the arrangement in the engine room, but the movement amount of the belt in the axial direction is small in order to obtain the same gear ratio, therefore Since the size of the entire system along the axial direction can be small, the wedge angle of the pulley is set small, preferably 30 ° or less. In general, the friction coefficient has an optimum range determined by the wedge angle.
At present, the system is used in a region where the friction coefficient is 0.3 or more from the viewpoint of prioritizing torque transmission of high horsepower.

However, if the friction coefficient is set to be high in this way, the noise level when the belt is running becomes high, and
There is a problem that the detachability of the belt from the pulley is deteriorated and an abnormal force is generated in the block, leading to its early breakage and cutting of the tension band.

Further, when the belt moves in the belt groove of the pulley in the radial direction at the time of gear shifting, if the coefficient of friction is high, the movement of the belt is hindered and smooth gear shifting becomes difficult. For this reason, the thrust required for gear shifting, that is, the lateral pressure applied to the belt from both sheaves must be made higher than the original required value, leading to an increase in operating force.

The present invention has been made in view of the above points, and its main purpose is to limit the coefficient of friction between the block and the pulley in the block belt within a predetermined range to improve the transmission performance of the belt. The noise level can be reduced without sacrificing much, the belt can be easily removed from the pulley to improve the durability of the belt, and the belt can be smoothly moved in the radial direction during shifting. To do.

[0011]

To achieve this object, in the invention of claim 1, the friction coefficient of the contact surface between the block and the pulley is determined by the belt transmission capacity and the wedge angle. Set the range and block
The contact part is made of synthetic resin made of phenolic composite material
On the other hand, on the surface of the belt groove of the pulley,
For surface treatment by plating or electroless nickel plating film
Do not perform surface treatment to disperse and plate the specified resin particles.
And

That is, according to the present invention, there is provided an endless flat belt having a large number of engaging portions formed on the upper and lower surfaces side by side in the longitudinal direction and having a core wire embedded therein.
A pair of tension bands, notch-shaped fitting grooves for fitting the tension bands on the left and right sides, and upper and lower surfaces of the fitting groove, respectively, which engage with the engaging portions of the tension band upper and lower surfaces, respectively. A large number of blocks having locking portions and abutting portions that come into contact with the belt groove surface of the pulley on the left and right side surfaces are provided. In a continuously variable transmission system in which a block belt for high load transmission, which is locked and fixed in the belt longitudinal direction with respect to a tension band, is spanned between a pair of variable pulleys, a contact portion of each block in the belt and a pulley Coefficient of friction with the belt groove surface of
Is set in the range of 0.16 ≦ μ ≦ tan (α / 2) for the wedge angle α of the pulley .

Further, each block of the block belt
The contact part of the is constructed with synthetic resin made of phenolic composite material.
On the other hand, on the surface of the belt groove of the pulley,
Surface treatment by aluminum plating or electroless nickel plating film
Disperse fluororesin particles such as Teflon (registered trademark) in
Perform surface treatment for plating.

According to the invention of claim 2, the structure of the invention of claim 1 is provided.
In addition to the composition, the phenolic composite of the contact part of each block
Carbon fiber is included in the synthetic resin made of material
It

[0015]

With the above construction, in the invention of claim 1, the coefficient of friction μ between the abutting portion of each block of the block belt and the belt groove surface of the pulley is t with respect to the wedge angle α of the pulley.
Since it is not more than an (α / 2), it is possible to prevent the belt from being wound around the pulley, and to significantly reduce the noise level when the belt is running. Moreover, it is possible to improve the detachability of the belt from the pulleys, avoid the occurrence of abnormal force in the block, and suppress the early breakage of the block and the breaking of the tension band. Further, at the time of gear shifting, the belt smoothly moves in the belt groove of the pulley in the radial direction, so that the operating force required for gear shifting can be reduced.

Further, since the coefficient of friction μ is 0.16 or more, the belt transmission ability required for the continuously variable transmission (CVT) for automobiles can be secured.

In addition, each block of the block belt abuts
Part is composed of synthetic resin made of phenolic composite material
The surface of the pulley's belt groove is coated with electroless nickel.
Fluorine resin for surface treatment or electroless nickel plating film
It has a surface treatment that disperses particles and plating
Therefore, while maintaining good workability and toughness of the block,
The friction coefficient μ can be easily reduced to tan (α / 2) or less.
I can .

According to the invention of claim 2, the invention of claim 1 is omitted.
A gear shifting system can be easily realized.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 schematically shows a belt type continuously variable transmission system A for high load transmission according to an embodiment of the present invention, and this transmission system A is used, for example, as a transmission (CVT) of an automobile. Reference numerals 1 and 2 denote driving and driven shafts that are arranged and supported in parallel with each other. The driving shaft 1 is provided with a driving pulley 3 composed of a variable pulley, and the driven shaft 2 is provided with a similar driven pulley 7. The drive pulley 3 is the drive shaft 1
A flange-shaped fixed sheave 4 fixed integrally and non-slidably to the drive shaft, and a flange-shaped fixed sheave 4 slidably and rotationally integrally connected to the drive shaft 1 so as to face the fixed sheave 4 by a spline or the like. A belt groove 6 having a movable wedge 5 and a V-shaped cross section having a predetermined wedge angle α (for example, 26 °) is formed between the sheaves 4 and 5.

On the other hand, the driven pulley 7 is the drive pulley 3 described above.
And a fixed sheave 8 fixed to the driven shaft 2 so as to rotate integrally and non-slidably, and a direction opposite to the facing direction of the movable sheave 5 with respect to the fixed sheave 4 of the drive pulley 3 on the fixed sheave 8. Driven shaft 2 so as to face each other
And a movable sheave 9 which is slidably and rotatably connected to each other. A belt groove 10 having the same wedge angle α as that of the drive pulley 3 is formed between the sheaves 8 and 9. A block belt B is wound around the belt grooves 6 and 10 of the drive and driven pulleys 3 and 7, and the drive and driven pulleys 3 and 7 are moved by a speed change mechanism such as a hydraulic mechanism (not shown). The sheaves 5 and 9 are moved toward and away from the fixed sheaves 4 and 8, respectively, to change the pulley diameters of the pulleys 3 and 7 (effective radius with respect to the belt B). For example, when the movable sheave 5 of the drive pulley 3 is brought closer to the fixed sheave 4 and the movable sheave 9 of the driven pulley 7 is separated from the fixed sheave 8, the pulley diameter of the drive pulley 3 is made larger than that of the driven pulley 7. , The rotation of the drive shaft 1 is accelerated and transmitted to the driven shaft 2. On the other hand, conversely, when the movable sheave 5 of the drive pulley 3 is separated from the fixed sheave 4 and the movable sheave 9 of the driven pulley 7 is brought closer to the fixed sheave 8 as shown in the figure, the pulley diameter of the drive pulley 3 is reduced. By increasing the pulley diameter of the driven pulley 7, the rotation of the drive shaft 1 is decelerated and transmitted to the driven shaft 2.

1 to 3, the block belt B has a plurality of endless core wires 13, 13, ... (Core bodies) parallel to each other inside a shape-retaining layer 12 made of rubber or the like. A pair of left and right endless tension bands 11 and 11 arranged and embedded in the left and right side fitting portions, as shown in FIG. 4, for fitting the tension bands 11 to the left and right side portions in a detachable manner in the width direction. Block 1 having notch-shaped fitting grooves 17 and 17 and contact portions 18 and 18 for contacting the belt grooves 6 and 10 side surfaces of the pulleys 3 and 7 on the left and right side surfaces.
6, 16 and so on, and the fitting groove 1 of each block 16
Tension bands 11 and 11 are fitted to 7 and 17, respectively, and the blocks 16 and 16 are continuously fixed in the belt longitudinal direction.

That is, in this block belt B, on the upper surface of each tension band 11, a large number of concave grooves 14, 14, ... Further, concave grooves 15, 15, ... As engaging portions having a constant pitch and extending in the width direction are formed on the lower surface in correspondence with the concave grooves 14, respectively. On the other hand, on the upper wall surface of the fitting groove 17 of each block 16, the ridge 1 as a locking portion that fits into each groove 14 on the upper surface of the tension band 11 is provided.
9 and on the lower wall surface of the fitting groove 17, there are formed ridges 20 as locking portions which fit into the respective grooves 15 on the lower surface of the tension band 11. 20
Are engaged with the concave grooves 14 and 15 of the tension band 11 to lock and fix the block 16 in the belt longitudinal direction.

As shown in FIG. 2, each of the blocks 16 is formed by embedding a reinforcing member 22 in a resin block main body 21 made of a phenolic composite material so as to be located substantially at the center thereof. The reinforcing member 22 includes upper and lower beams 22a and 22b extending in the belt width direction (horizontal direction).
And a center pillar 22c that vertically connects the left and right central portions of the both beams 22a and 22b to each other.
It is formed in a letter shape.

Left and right contact portions 1 in each of the blocks 16
The angle formed by 8 and 18 is the same as the wedge angle α of the pulleys 3 and 7.

[0025] Then, the friction coefficient mu between the side surface of the belt groove 6 and 10 of the contact portions 18 and the pulley 3,7 in the block 16, is a 0.16 ≦ μ ≦ tan (α / 2) (Preferably μ ≧ 0.19). That is,
When the coefficient of friction μ is lower than 0.16, the transmission capability of the belt B required for the continuously variable transmission system for high load transmission is reduced, so the friction coefficient μ is set to 0.16 or more. Also,
If the friction coefficient μ increases beyond tan (α / 2), the effect of the present invention cannot be obtained reliably, so tan (α / 2)
It is set below.

When lowering the friction coefficient μ to tan (α / 2) or less, for example, at least the contact portions 18, 18 of the block body 21 made of a synthetic resin made of a phenolic composite material in the block 16 To contain carbon fiber, surface treatment of belt grooves 6, 10 of pulleys 3, 7 by electroless nickel plating, or dispersion of Teflon (registered trademark) particles as fluororesin in electroless nickel plating film There is a method of applying a surface treatment for plating and a method of combining both methods, and it is possible to easily reduce the friction coefficient μ.

In the above method, the friction coefficient μ can be lowered by increasing the carbon fiber content, but the workability of the block 16 (specifically, the block body 21) is increased with the increase of the carbon fiber content. And deterioration of toughness are observed. On the other hand, the method (1) is advantageous in that such a problem does not occur and the coefficient of friction μ can be lowered while maintaining good workability and toughness of the block 16. Particularly, when the friction coefficient μ is set to μ ≧ 0.19, it is preferable to perform the surface treatment only by electroless nickel plating. The method is preferable, and the friction coefficient μ can be significantly reduced.

Therefore, in the above embodiment, the friction coefficient μ between each contact portion 18 in each block 16 of the block belt B and the side surface of the belt groove 6, 10 of the pulley 3, 7 is equal to that of the pulley 3, 7. For wedge angle α, μ ≦ tan (α /
2), the block belt B is pulley 3,
In the state where the load is transmitted by engaging with the side surfaces of the belt grooves 6 and 10 of 7, the winding phenomenon of the belt B is effectively reduced. As a result, it is possible to significantly reduce the noise level when the belt B is running, and it is possible to improve the detachability of the belt B from the pulleys 3 and 7 and to prevent an excessive force from being generated in the block 16, which is an early stage. The life of the belt B can be extended by suppressing breakage and cutting of the tension band 11. Further, at the time of gear shift, the belt B has the belt grooves 6, 6 of the pulleys 3, 7.
Since it smoothly moves in the radial direction within 10, the thrust applied on the driven pulley 7 side is smoothly transmitted, the thrust on the drive pulley 3 side increases, and the operating force required for gear shifting can be reduced and the belt B The load applied to can be reduced.

Further, since the friction coefficient μ is 0.16 or more, the continuously variable transmission system A (CVT) for high load transmission.
It is possible to satisfactorily secure the transmission capacity of the belt B required for the above.

The present inventor carried out various experiments by winding the block belts B corresponding to the drive and driven pulleys 3 and 7 with the wedge angle α set to α = 26 ° and running them. First, the relationship between the friction coefficient μ and noise is as shown in FIG. 6, and it can be seen that the noise level decreases as the friction coefficient μ decreases.

Further, the axial load between the pulleys 3 and 7 is 250 kg.
When the relationship between the transmission capacity ST of the belt B and the friction coefficient μ is examined as f, the result is as shown in FIG. 7, and the transmission capacity ST is μ =
The maximum value is 0.23 (= tan (α / 2)), and the lower the value is, the smaller it is, but if μ ≧ 0.16 (preferably μ ≧ 0.19), it is usually for automobiles. 2000Kg / m or more transmission capacity ST required for continuously variable transmission
Therefore, it can be seen that the effect of the present invention is effective.

Further, FIG. 8 shows a relationship between the thrust detected by the drive pulley 3 and the friction coefficient μ when a constant thrust is applied to the driven pulley 7. According to FIG. 8, the driving-side thrust becomes maximum when μ = 0.23 or less, and decreases when it exceeds it.

Finally, while the belt B is running, each block 1
The stress which the lower part of 6 receives from the pulleys 3 and 7 was measured by a strain gauge, and the result is shown in FIG. Friction coefficient μ is μ = 0.4
In the conventional example of 6 (> tan (α / 2)), the reverse force, which is considered to be the mesh of the belt B, is generated at the inlet and outlet of the pulleys 3 and 7, whereas μ = 0. In the example of the present invention of No. 0.16, these phenomena disappeared and a smooth pressure waveform was obtained, which proves that the present invention is effective.

[0034]

As described above, according to the first aspect of the invention, the coefficient of friction μ between each block of the high load transmission block belt and the pulley is 0.16 or more with respect to the wedge angle α of the pulley. And set within the range of tan (α / 2) or less
The block belt contact points
Made of synthetic resin made of phenolic composite material,
The surface of the belt groove of the electroless nickel plated surface
Fluorine resin particles dispersed in treated or electroless nickel plated film
Since a configuration subjected to a surface treatment for plating by, Bro
The workability and toughness of the belt are kept good and the transmission capacity of the belt is sufficiently secured, while the noise level when the belt is running can be greatly reduced, and the detachability of the belt from the pulley is improved. , It is possible to suppress the deterioration of the belt durability due to the early breaking of the block, the breaking of the tension band, etc.
Further, it has a practically excellent effect that the belt can be smoothly moved in the belt groove of the pulley in the radial direction at the time of gear shifting to reduce the gear shifting operation force.

According to the invention of claim 2, the invention of claim 1
Containing carbon fiber in resin of block in
The friction coefficient μ is tan
It is easy to achieve lower than (α / 2) and
Achieves the same purpose while maintaining better workability and toughness
can do.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view showing a part of a block belt according to an exemplary embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a side view of the belt.

FIG. 4 is an enlarged perspective view of a block.

FIG. 5 is a schematic sectional view schematically showing a continuously variable transmission system.

FIG. 6 is a characteristic diagram showing a relationship between a friction coefficient and noise.

FIG. 7 is a characteristic diagram showing a relationship between a friction coefficient and a belt transmission capacity.

FIG. 8 is a characteristic diagram showing a relationship between a friction coefficient and a driving pulley thrust.

FIG. 9 is a characteristic diagram showing a stress change in a block while the belt is running.

[Explanation of symbols]

 A continuously variable transmission system 3, 7 pulley 6, 10 belt groove B block belt 11 tension band 13 core wire 14, 15 concave groove (engaging portion) 16 block 18 abutting portion 19, 20 ridge (locking portion) 21 Block body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichi Okawa, Koichi Okawa, 3-2-15 Meiwadori, Hyogo-ku, Kobe, Hyogo Prefecture Bando Kagaku Co., Ltd. (72) Mitsunao Takayama 1518 Sakyoyama, Midori-ku, Nagoya-shi, Aichi (72) Inventor Takahiko Uunase 17-10 Moto-Sakurada-cho, Minami-ku, Nagoya-shi, Aichi (72) Inventor Kozo Yamauchi 1-1209 Hirani, Tenshiro-ku, Nagoya-shi, Aichi 301 Krantz Kanda 301 (72) Inventor Takeshi Nakazawa Nagoya, Aichi-ken No. 8 Aichi Dormitory, 1-1-3 Tamafunecho, Nakagawa-ku, Yokohama (72) Inventor Masao Iwata 961-1, Nishiko Isshiki, Sobue Town, Nakajima District, Aichi Prefecture (56) Reference JP-A-62-237137 (JP) , A) JP-A-63-34342 (JP, A)

Claims (2)

(57) [Claims] 1. A pair of tension bands composed of endless flat belts each having a plurality of engaging portions formed on the upper and lower surfaces side by side in the longitudinal direction and having core wires embedded therein, and left and right side surfaces. A notch-shaped fitting groove for fitting the tension band,
A large number of engaging portions formed respectively on the upper and lower surfaces of the fitting groove and engaging with the engaging portions on the upper and lower surfaces of the tension band, and abutting portions on the left and right side surfaces that abut the belt groove surface of the pulley. A block, and by engaging the engaging portion of the tension band and the locking portion of each block,
In a continuously variable transmission system in which a block belt for high load transmission in which a block is locked and fixed to a tension band in a belt longitudinal direction is laid between a pair of variable pulleys, a contact portion of each block in the belt is and the dynamic friction coefficient mu is wedge angle of the pulley alpha between the belt groove surface of the pulley, Ri range near the 0.16 ≦ μ ≦ tan (α / 2), phenolic abutting portion of each block in the belt composite
The belt groove surface of the pulley is made of synthetic resin , and electroless nickel plating or
Disperse the fluorine resin particles in the electrolytic nickel plating film
A continuously variable transmission system characterized by being subjected to a surface treatment that reduces the friction . 2. A phenol at a contact portion of each block
Containing carbon fiber in resin made of composite material
The continuously variable transmission system according to claim 1, wherein the continuously variable transmission system is provided.