JPH10196748A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the thickness of a belt uniform in regard to the direction to which the belt is subjected to tension by forming ribs along its revolving direction to which the belt is subjected to tension, increase the section modulus of the belt though it is small in size by providing the ribs, and thereby lengthen the life of the belt. SOLUTION: Each power transmitting ring 8 made of a resin is provided for variable speed pulleys 3 and 4 disposed to input/output shafts 1 and 2 in such a way that it can be off-centered, and a rubber belt 5 is installed between the power transmitting rings 8. A plurality of ribs 5b laid along the running direction, are provided for the inner circumferential surface of the rubber belt 5. These ribs 5b are fitted in circumferential grooves 8c formed in the outer circumferential surface of each power transmitting ring 8. The thickness of the belt can be made uniform in regard to the direction to which the belt is subjected to tension, and the belt can thereby obtained, which is small in size, and long in life. Since the cross section of each power transmitting ring 8 is formed roughly into a trapezoidal shape, its behavior is stable at all time even if it is subjected to holding force.

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 that is used, for example, as a power transmission mechanism of an automobile or a two-wheeled vehicle and that changes a gear ratio steplessly.

[0002]

2. Description of the Related Art As a continuously variable transmission of this type, a belt is stretched between variable speed pulleys on the input side and the output side, and the diameters of the variable speed pulleys are changed. , There are those that continuously and continuously change gears. In general, a variable speed pulley of this type of continuously variable transmission includes a fixed pulley main body fixed to a transmission shaft, and a movable pulley that defines a V groove between the fixed pulley main body and is movable in the axial direction of the transmission shaft. With the subject.

Conventionally, a continuously variable transmission using a steel belt has been provided. This steel belt generally consists of a number of metal blocks assembled in a chain with steel strips, and is considerably heavy. Therefore, there is a problem that abrasion, vibration, and noise are generated between the pulley main body and the metal block or at the contact portion between the metal blocks due to the centrifugal force caused by the rotation.

On the other hand, when a rubber belt is used, power is transmitted on the side surface of the rubber belt, so that it is necessary to increase the area of the side surface of the rubber belt, and as a result, the belt size becomes large. Further, the belt is bent at a portion wound around the pulley. Therefore, when the thickness of the entire rubber belt is increased in order to increase the area of the side surface, a high bending stress is generated. Therefore, it is necessary to increase the area of the side surface while keeping the bending stress low. For this purpose, a groove is provided on the inner peripheral surface of the belt at predetermined intervals so as to cross the belt in the width direction. It is necessary to use a toothed belt type. However, in this case, with respect to the direction in which the belt receives tension, thick portions and narrow portions exist alternately, and in such thin portions, a decrease in the tensile strength of the belt is expected. , The belt size needs to be increased.

As described above, since the rubber belt has a large belt size in any case, if the range of the gear ratio is widened, the continuously variable transmission becomes large. On the contrary, if the rubber belt is made compact in order to make the continuously variable transmission compact, the life of the rubber belt may be shortened. Therefore, between the fixed pulley main body and the movable pulley main body,
An annular power transmission ring having a V-shaped cross section, which is made of a material that is stronger and more rigid than rubber, is sandwiched, and a rubber belt having teeth is wound around the outer circumference of the power transmission ring. See Japanese Utility Model Laid-Open No. 63-126653).

However, since this power transmission ring is formed in a V-shaped cross section having a pair of flange plates opened in a V-shape on both circumferential sides of the ring, a clamping force is exerted between both pulley main bodies. As a result, the flange plate is deformed, which causes a problem that the behavior of the power transmission ring becomes unstable.
In addition, since a toothed belt is used and there is a groove (teeth) extending in a direction orthogonal to the direction in which the belt receives tension, a decrease in tensile strength is expected as described above,
The belt size needs to be increased.

[0007] A general shifting method in a continuously variable transmission is as follows. That is, in one of the variable speed pulleys, when the pitch diameter is increased or decreased by moving the movable pulley main body, the movable pulley main body in the other variable speed pulley biases the same in the other variable speed pulley. Is moved in the axial direction to the position where the urging force and the tension of the belt are balanced to decrease or increase the pitch diameter.

[0008] In this case, at the time of a high load, the force of the other variable speed pulley for moving the movable pulley main body closer to the fixed pulley main body side against the spring member becomes stronger. In order to maintain the pitch diameter against this strong force, the biasing force of the spring member must be considerably strong. However, the spring member having such a strong force as to maintain the pitch diameter of the other variable speed pulley under high load exerts a large tension on the belt even under low load. For this reason, the life of the rubber belt is shortened.

It is an object of the present invention to provide a small-sized and long-lasting continuously variable transmission using a rubber belt.

[0010]

To achieve the above object, in a continuously variable transmission according to a first aspect of the present invention, a variable speed pulley is arranged on at least one of the input side and output side transmission shafts, and a rubber belt is hung on the variable speed pulley. In the delivered continuously variable transmission, the variable speed pulley has a variable width V groove formed between the facing surfaces of a pair of pulley main bodies, and a rubber belt is wound around the outer peripheral surface, and the pulley main body is provided between the facing surfaces. A power transmission ring made of a resin having a substantially trapezoidal cross section which is sandwiched eccentrically with respect to the inner peripheral surface of the rubber belt, and a plurality of ribs extending along the circumferential direction of the rubber belt are provided side by side, The outer peripheral surface of the power transmission ring is formed with a plurality of peripheral grooves into which the ribs are fitted.

In the conventional toothed rubber belt, the thickness is not uniform in the direction in which the belt receives tension, so that the tensile strength of the belt is weakened in the thin portion, and the life may be shortened. Was. On the other hand, in the present invention, since the ribs are formed along the circumferential direction, which is the direction in which the belt receives tension, the thickness of the belt can be made uniform in the direction in which the belt receives tension, and the ribs are provided. As a result, the section modulus of the belt can be increased in spite of its small size, and the life of the belt can be extended. The rib may have a V-shaped or trapezoidal cross section.

Further, in the conventional power transmission ring having a V-shaped cross section, the behavior is unstable due to deformation due to the sandwiching force of both pulleys, but the power transmission ring of the present invention has a substantially trapezoidal cross section, so It is hardly deformed even if it is held by the pulley, and its behavior is stable. Further, if the cross section is substantially trapezoidal, the circumferential groove for fitting the rib of the rubber belt can be easily formed, and there is no possibility that the strength is reduced due to the circumferential groove.

A continuously variable transmission according to a second aspect of the present invention is a continuously variable transmission in which a variable speed pulley is arranged on at least one of the input side and output side transmission shafts and a rubber belt is stretched over the variable speed pulley. A variable width V groove formed between the facing surfaces of the pair of pulley main bodies, and a power transmission ring in which a rubber belt is wound around the outer peripheral surface and is eccentrically sandwiched between the facing surfaces with respect to the pulley main body. At least one of the pair of pulley main bodies includes a movable pulley main body that is movable in the axial direction of the transmission shaft. An elastic member that elastically urges the movable pulley main body toward the other pulley main body, and a transmission torque. And a torque cam mechanism for urging the movable pulley main body toward the other pulley main body side in accordance with the increase of the torque pulley.

In this configuration, the force for urging the movable pulley main body is obtained by the elastic member independent of the transmission torque and the torque cam mechanism that depends on the transmission torque. For this reason, even when the urging force by the elastic member is set to be relatively weak, the urging force is increased by the torque cam mechanism at a high load, and the contact diameter of the power transmission ring can be maintained. On the contrary, when the load is low, the biasing force of the torque cam mechanism is reduced while the elastic member having the weak biasing force is mainly used to obtain the biasing force, so that the belt tension at the low load can be reduced as much as possible. , Belt life can be increased.

A continuously variable transmission according to a third aspect of the present invention is a continuously variable transmission in which a belt is stretched between a pair of variable speed pulleys respectively disposed on the input side and output side transmission shafts. , A fixed pulley main body fixed to the corresponding transmission shaft, a movable pulley main body which forms a V groove between the fixed pulley main body and is movable in the axial direction of the transmission shaft, and a belt is wound around the outer peripheral surface of the main body. A power transmission ring made of a resin having a trapezoidal cross section sandwiched between the opposing surfaces of both pulley main bodies so as to be eccentric to the pulley main body, and extending along the circumferential direction of the rubber belt on the inner peripheral surface of the rubber belt. A plurality of ribs are arranged side by side, and a plurality of circumferential grooves into which the ribs are fitted are formed on the outer peripheral surface of the power transmission ring, and one variable speed pulley is provided to set a gear ratio. Movable pulley main body A means for adjusting the axial position is provided, and the other variable speed pulley has an elastic member for urging the movable pulley main body to the other side and a movable pulley main body for the fixed pulley main body side according to the increase of the transmission torque. And a biasing torque cam mechanism.

In the above configuration, when the axial position of the movable pulley is adjusted in one of the variable speed pulleys, the contact diameter of the power transmission ring with respect to the one variable speed pulley changes. Accordingly, in the other variable speed pulley,
The power transmission ring changes the contact diameter to a position that balances the biasing force of the elastic member and the torque cam mechanism. In addition, since the ribs are formed along the circumferential direction in which the belt receives tension, the thickness of the belt can be made uniform in the direction in which the belt receives tension. Of the belt can be increased, and the life of the belt can be extended. The rib may have a V-shaped or trapezoidal cross section.

Moreover, since the torque cam mechanism can generate an urging force according to the load, the urging force of the elastic member can be set weakly, and as a result, the belt tension at a low load can be reduced.
As a result, the belt life can be further extended. According to a fourth aspect of the present invention, in the continuously variable transmission according to the third aspect, the means for adjusting the axial position of the movable pulley main body pushes the movable pulley main body toward the other pulley main body side by increasing a turning diameter by centrifugal force. It is characterized by including an inertia member and a member for partitioning the space for accommodating the inertia member between the main body of the movable pulley and the space narrowing radially outward.

When the rotational speed increases and the centrifugal force acting on the inertial member increases, the inertial member moves radially outward in the space for accommodating the inertial member, and accordingly pushes the movable pulley main body in the axial direction. Get thrust. The gear ratio can be changed with a simple structure. According to a fifth aspect of the present invention, in the continuously variable transmission according to any one of the second to fourth aspects, the elastic member is interposed between a receiving member fixed to a transmission shaft and a movable pulley main body,
The torque cam mechanism includes a groove formed in one of the receiving member and the movable pulley main body, and a shaft member formed in the other and guided by an inner surface of the groove.

In this configuration, since the torque cam mechanism is formed by fitting the shaft member into the groove, the structure of the torque cam mechanism can be simplified. In addition, since the groove or the shaft member of the torque cam mechanism is provided on the receiving member that receives the elastic member, the structure can be simplified through dual use of the member.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic sectional view of a continuously variable transmission according to the present invention. Referring to FIG.
Have variable speed pulleys 3, 4 on the input shaft 1 and the output shaft 2, respectively.
And a rubber belt 5 between these variable speed pulleys 3 and 4.
Is spread over. This embodiment is an example applied to a transmission of an automobile. The input shaft 1 is, for example, a crankshaft of an engine 100 of the automobile, and the output shaft 2 is, for example, an axle of the front wheel 101.

The variable speed pulley 3 on the input shaft 1 side includes a fixed pulley main body 6 fixed to the input shaft 1 and a movable pulley main body 7 which is integrally rotatable with the input shaft 1 and is movably mounted in the axial direction. , Sandwiched between both pulley main bodies 6 and 7,
A power transmission ring 8 made of synthetic resin that can be eccentric to the pulley bodies 6 and 7, and a centrifugal speed ratio adjustment mechanism that brings the movable pulley body 7 close to the fixed pulley body 6 according to the rotation speed of the input shaft 1. 9 is provided.

Opposing surfaces 6a, 7a of the two pulley main bodies 6, 7
Is formed into a conical tapered surface. On the other hand, the power transmission ring 8 is made of synthetic resin having a substantially trapezoidal cross section, and has both circumferential side surfaces in sliding contact with the corresponding opposing surfaces 6a and 7a. Also, as shown in FIG.
Is formed with a transmission surface with the rubber belt 5. The inner peripheral surface 5a of the rubber belt 5 is provided with a plurality of ribs 5b extending in the circumferential direction of the rubber belt 5, and the outer peripheral surface 8a of the power transmission ring 8 is formed with an annular recess 8b. The rib 5b is formed on the bottom surface of the annular recess 8b.
A plurality of peripheral grooves 8c are formed to fit each other.

The movable pulley main body 7 includes an inner cylindrical portion 71,
An outer cylinder portion 73 is provided, and an inclined disk portion 72 connecting the two cylinder portions 71, 73 is provided. The inner cylinder portion 71 is spline-coupled to the spline portion 1 a formed on the input shaft 1. One surface of the disk portion 72 constitutes the facing surface 7a,
The other surface of the disc portion 72 is also a tapered surface 74. The gear ratio adjusting mechanism 9 is provided in a housing space 92 formed between a disk-shaped fixing member 91 fixed to the input shaft 1 and the movable pulley main body 7 opposed thereto, for example, an inertia made of a sphere. It is formed by accommodating a plurality of members 93.

The accommodating space 92 has, between the inner cylinder portion 71 and the outer cylinder portion 73, the taper surface 74 that constitutes the back surface of the disk portion 72 and the taper surface 94 of the fixing member 91 that faces the taper surface 74.
And are divided by When the rotation speed of the input shaft 1 increases, the centrifugal force acting on the inertia member 93 increases accordingly, and the inertia member 93 moves outward in the radial direction as shown in FIG. Thereby, the movable pulley main body 7 approaches the fixed pulley main body 6 side, and accordingly, the contact diameter of the power transmission ring 8 increases.

The variable speed pulley 4 on the output shaft 2 side includes a fixed pulley main body 10 fixed to the output shaft 2 and a movable pulley main body 20 rotatably linked to the output shaft 2 and movably in the axial direction. A power transmission ring 8 made of resin sandwiched between the pulley bodies 10 and 20 and eccentric to the pulley bodies 10 and 20;
, Which are elastic members for elastically urging the movable pulley main body 20 toward the fixed pulley main body 10 side, and a torque cam for urging the movable pulley main body 20 toward the fixed pulley main body 10 side in accordance with an increase in transmission torque. And a mechanism 40.

The opposing surfaces 10a of the two pulley bodies 10, 20
20a is formed in a conical tapered surface. The fixed pulley main body 10 has the same configuration as the fixed pulley main body 5 of the variable speed pulley 3 on the input shaft 1 side, but in the opposite direction. The movable pulley main body 20 includes an inner cylindrical portion 21 and an outer cylindrical portion 2.
3 and an inclined disc portion 22 connecting the two tubular portions 21 and 23
And The inner cylinder portion 21 is fitted to the input shaft 2 in a state where rotation and axial movement are allowed. One surface of the disk portion 22 constitutes the facing surface 20a. Disk part 2
A disk-shaped receiving member 50 fixed to the output shaft 2 is opposed to the other surface of the disk 2. Member 5
0, the movable pulley main body 20 is elastically biased toward the fixed pulley main body 10 side. The reason why a pair of inner and outer compression coil springs 31 and 32 are used as the elastic member is that the movable pulley main body 20 is uniformly urged so that the movable pulley main body 20 is not twisted with respect to the output shaft 2. To do that. A plurality of compression coil springs may be arranged on the circumference of the disk portion 22 at equal intervals.

Referring to FIG. 3, the outer cylinder 23 has
Groove 24 inclined with respect to the rotation direction of movable pulley main body 20
Are formed at opposing positions on the circumference. FIG.
With reference to FIG. 3 and FIG. 3, the torque cam mechanism 40 includes the groove 24 formed in the outer cylindrical portion 23 of the movable pulley main body 20.
And a shaft member 41 fitted in the groove 24. The shaft member 41 is fixed to the outer peripheral flange portion 51 of the receiving member 50. In the variable speed pulley 4, the route for transmitting the torque of the rubber belt 5 to the output shaft 2 is from the power transmission ring 8 to the fixed pulley main body 10.
And a second route transmitted from the power transmission ring 8 to the output shaft 2 via the movable pulley main body 20 and the torque cam mechanism 40.

In the torque cam mechanism 40, when the torque to be transmitted increases and the phase between the receiving member 50 and the movable pulley main body 20 is deviated, the movable pulley main body 20 is moved to the fixed pulley main body 10 side according to the phase deviation amount. The thrust that causes it is generated. This thrust increases as the transmission torque increases. Since the outer peripheral flange portion 51 of the receiving member 50 is arranged to enter the inside of the outer tubular portion 23 of the movable pulley main body 20, the compression coil is compressed around the output shaft 2 by the receiving member 50 and the movable pulley main body 20. An accommodating space 33 for accommodating the springs 31 and 32 in a substantially sealed state is formed.

The torque cam mechanism is the torque cam mechanism 4 described above.
Instead of the shaft member 41 and the groove 24 of 0, as shown in FIGS. 5A and 5B, the outer cylindrical portion 121 and the outer peripheral flange portion 1 which are the contact portions of the movable pulley main body 120 and the receiving member 150.
The end surfaces of the 51 may be formed in a meshing manner so as to mesh with each other. In this case, the tapered cam surfaces 122 and 152 provided at the meshing portions may be meshed with each other.

Next, the operation of the above-described continuously variable transmission will be described. When the rotation speed of the engine increases, as shown in FIG. 4, in the variable speed pulley 3 on the output shaft 1 side, the inertia member 93 moves in a centrifugal direction (radially outward) due to an increase in centrifugal force. As the movable pulley main body 7 approaches the fixed pulley main body 6, the contact diameter of the power transmission ring 8 increases.

On the other hand, in the variable speed pulley 3 on the output shaft 2 side, the contact diameter of the power transmission ring 8 is reduced to a position where the power transmission ring 8 balances the biasing force of the compression coil springs 31 and 32 as elastic members and the torque cam mechanism 40. . In this way, since the contact diameter increases on the input side and the contact diameter decreases on the output side, the rotation speed of the output shaft becomes relatively large with respect to the rotation speed of the input shaft. That is, the gear ratio can be reduced in accordance with an increase in the engine speed.

In this embodiment, the gear ratio can be automatically changed according to the engine speed. In particular, since the ribs are formed along the circumferential direction, which is the direction in which the rubber belt 5 receives the tension, it is possible to increase the sectional modulus of the belt by the ribs while making the thickness of the rubber belt 5 uniform in the direction in which the rubber belt 5 receives the tension. The rubber belt 5 having a small size and a long life can be obtained. This makes it possible to obtain a continuously variable transmission that is small and has a long life.

Further, since the urging force corresponding to the transmission torque can be obtained by the torque cam mechanism 40, the urging force of the compression coil springs 31, 32 as elastic members can be reduced. As a result, the belt tension at a low load can be reduced as much as possible, and as a result, the life of the belt can be increased. Further, since the power transmission ring 8 has a substantially trapezoidal cross section, it is difficult to be deformed even if it receives a clamping force from both pulley main bodies 6, 7; 10, 20 and the behavior is stable. Sufficient strength can be maintained even if the peripheral groove 8c into which the 5b is fitted is formed.

Furthermore, since a centrifugal mechanism is used as the speed ratio adjusting mechanism 9, the speed ratio can be easily and automatically changed with a simple structure. Further, the torque cam mechanism 40 is connected to the groove 2
Since this is realized by a simple configuration in which the shaft member 41 is fitted to the shaft 4, the continuously variable transmission A can also be reduced in size in this respect.
A receiving member 50 for receiving the compression coil springs 31 and 32
In addition, since the shaft member 41 of the torque cam mechanism 40 is provided, the structure can be simplified by sharing the members.

In the above embodiment, the groove of the torque cam mechanism 40 may be provided on the receiving member 50, and the shaft member may be attached to the movable pulley main body 20. The movable pulley main body 20 is replaced with the receiving member 5 instead of the shaft member and the groove.
The torque cam mechanism may be configured by screwing to either one of 0 and the output shaft 2. In the above-described embodiment, a centrifugal mechanism that pushes the movable pulley main body 7 in the axial direction using the inertia member 93 is used as the speed ratio adjusting mechanism 9, but instead of this, a hydraulic cylinder as shown in FIG. The position of the movable pulley main body 7 in the axial direction may be adjusted by using 130 or using a motor 170 as shown in FIG. In these cases, for example, the control unit, which receives the rotation speed signal from the engine rotation speed sensor, issues a signal for operating the hydraulic cylinder 130 and the motor 170 based on the above signal.

Referring to FIG. 6, a disk-shaped fixing member 131 fixed to the input shaft 1 includes an outer cylindrical portion 132 and an inner cylindrical portion 13.
4 are provided. The outer cylindrical portion 132 of the fixed member 131 is fitted into the outer cylindrical portion 73 of the movable pulley main body 7, and a gap therebetween is sealed by a seal member 133, and the inner cylindrical portion 134 of the fixed member 131 is fixed to the movable pulley main body 7. The inner cylinder portion 71 is fitted and sealed between them by a seal member 135. An oil chamber 136 of the hydraulic cylinder 130 is defined by the fixing member 131 between the outer cylindrical portion 71 and the inner cylindrical portion 73 of the movable pulley main body 7, and oil is sealed therein. The movable pulley main body 7 is pushed toward the fixed pulley main body 6 by the pressure of the oil introduced into the oil chamber 136.

An oil passage 137 communicating with the oil chamber 136 through the inside of the input shaft 1 is formed in the fixing member 131. An oil passage 161 connecting the oil passage 137 and the tank 160 is driven by a motor 162 to move the oil in the tank 160 through the check valve 164 to the oil chamber 1.
A pump 163 that leads to the 36 side is connected. In the figure, reference numeral 166 is an electromagnetic switching valve (directional control) that is controlled so as to be closed when oil is supplied to the oil chamber 136 side by the pump 162 and opened when the oil in the oil chamber 136 is returned to the tank 160. Valve). 165 is
This is a relief valve for releasing oil to the tank 160 in the oil chamber 136 when the pressure in the oil chamber 136 becomes excessively high. The control unit 167 which receives the rotation speed signal controls the operations of the motor 162 for driving the hydraulic cylinder 130 and the switching valve 166 based on the signal.

Next, referring to FIG. 7, the continuously variable transmission A
The cover 171 is formed with a cylindrical bulge 172, and the outer end surface of the bulge 172 has the motor 170.
The body of is fixed. Rotating shaft 1 of this motor 179
73 penetrates into the bulging portion 172 and has a screw 174 on the outer peripheral surface.
Is integrally rotatably connected to the cylindrical rotating body 175 having the structure. The rotating body 175 is supported by the input shaft 1 via a rolling bearing 176, and
It is located within 2.

Further, a cylindrical slide body 177 having a screw 178 screwed with the screw 174 on the outer periphery of the rotating body 175 formed on the inner periphery thereof has a spline portion 179 on the outer periphery thereof and a bulging portion 1
It is provided slidably in the axial direction in a state of being splined to the spline portion 180 on the inner peripheral surface of 72.
When the rotating body 175 is rotationally driven by the motor 170,
The slide body 177 is moved in the axial direction to push the movable pulley main body 7 toward the fixed pulley main body 6 side. The control unit 167 that receives the rotation speed signal controls the operation of the motor 170 based on the signal.

In the above embodiment, the variable speed pulley 3
Instead of using the gear ratio adjusting mechanism 9 for directly pressing the movable pulley main body 7, a mechanism for urging the movable pulley main body 7 toward the fixed pulley main body 6 by an elastic member such as a compression coil spring is adopted. The gear ratio may be determined by, for example, actively pushing the loose rubber belt 5 using an auto-tensioner mechanism or the like to decenter the power transmission ring 8.

Further, in the above embodiment, only one of the pair of pulley main bodies provided in the variable speed pulley is movable, but both may be movable. Further, in the above embodiment, the variable speed pulleys 3, 3 are provided on both the input shaft 1 and the output shaft 2.
4, the variable speed pulley is arranged only on one of the transmission shafts, and the gear ratio is determined by a mechanism that applies tension to the loose belt using the above-described auto tensioner mechanism. good.

In addition, various changes can be made within the scope of the present invention, such as application to other known drive transmission mechanisms of the present invention.

[0043]

According to the first aspect of the invention, since the ribs are formed along the circumferential direction, which is the direction in which the belt receives the tension, the thickness of the belt can be made uniform in the direction in which the belt receives the tension. By providing the ribs, it is possible to increase the section modulus of the belt while being small in size, and to extend the life of the belt. As a result, it is possible to obtain a compact and long-life continuously variable transmission. The cross section of the power transmission ring has a substantially trapezoidal shape, so it is difficult to deform even when subjected to pinching force, the behavior is stable, and sufficient strength can be maintained even if a circumferential groove for fitting the rib of the rubber belt is formed. .

According to the second aspect of the present invention, the biasing force for maintaining the contact diameter of the power transmission ring is obtained by the elastic member and the torque cam mechanism, and the biasing force corresponding to the transmission torque can be obtained by the torque cam mechanism. Since it is possible, the urging force of the elastic member can be reduced. As a result, the belt tension at a low load can be reduced as much as possible, and as a result, the life of the belt can be increased.

According to the third aspect of the present invention, when the contact diameter is changed by adjusting the axial position of the movable pulley main body in one of the variable speed pulleys,
The power transmission ring changes the contact diameter to a position that balances the biasing force of the elastic member and the torque cam mechanism. Thereby, the gear ratio can be automatically changed.
Further, the same effects as those of the first and second aspects of the present invention can be achieved, and a small-sized belt having tensile strength can be obtained and the belt tension at a low load can be reduced. A transmission can be obtained.

According to the fourth aspect of the present invention, since the centrifugal mechanism is used, the gear ratio can be easily changed with a simple structure. According to the fifth aspect of the invention, since the torque cam mechanism is configured by fitting the shaft member into the groove, the structure of the torque cam mechanism can be simplified. Further, since the groove or the shaft member of the torque cam mechanism is provided on the receiving member receiving the elastic member,
The structure can be simplified through shared use of members.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a continuously variable transmission according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a continuously variable transmission in which the gear ratio is changed from the state of FIG.

FIG. 3 is a partially cutaway side view of a variable speed pulley on an output side.

FIG. 4 is an enlarged sectional view of a main part of a belt and a power transmission ring.

FIG. 5A is a side view of another embodiment of the torque cam mechanism of the present invention, and FIG. 5B is a cross-sectional view taken along line II of FIG.

FIG. 6 is a schematic configuration diagram of another embodiment of the speed ratio adjustment mechanism of the present invention.

FIG. 7 is a schematic configuration diagram of another embodiment of the speed ratio adjusting mechanism of the present invention.

[Explanation of symbols]

 1 input shaft 2 output shaft 3,4 variable speed pulley 5 rubber belt 5a inner peripheral surface 5b rib 6 fixed pulley main body 6a, 7a facing surface 7 movable pulley main body 74 taper surface 8 power transmission ring 8a outer peripheral surface 8c peripheral groove 9 gear ratio adjustment Mechanism 91 Fixed member 92 Housing space 93 Inertial member 94 Tapered surface 10 Main body of fixed pulley 20 Main body of movable pulley 10a, 20a Main surface 24 Groove 31, 32 Compression coil spring (elastic member) 40 Torque cam mechanism 41 Shaft member 130 Hydraulic cylinder 170 Motor

Claims (5)

[Claims] 1. A continuously variable transmission in which a variable speed pulley is arranged on at least one of an input side and an output side transmission shaft and a rubber belt is stretched around the variable speed pulley, wherein the variable speed pulley is provided between a pair of opposed surfaces of a pulley main body. And a power transmission ring made of a resin having a substantially trapezoidal cross section in which a rubber belt is wound around the outer peripheral surface and is eccentrically held between the opposing surfaces with respect to the pulley main body. On the inner peripheral surface of the rubber belt, a plurality of ribs extending in the circumferential direction of the rubber belt are provided in parallel, and on the outer peripheral surface of the power transmission ring, a plurality of peripheral grooves for fitting the ribs are formed. A continuously variable transmission characterized by the following. 2. A continuously variable transmission in which a variable speed pulley is arranged on at least one of an input side and an output side transmission shaft and a rubber belt is stretched around the variable speed pulley. And a power transmission ring in which a rubber belt is wound around the outer peripheral surface and is eccentrically sandwiched between the opposing surfaces with respect to the pulley main body, and at least one of the pair of pulley main bodies One is composed of a movable pulley main body that is movable in the axial direction of the transmission shaft, an elastic member that elastically biases this movable pulley main body toward the other pulley main body, and the movable pulley main body according to the increase of the transmission torque. And a torque cam mechanism for urging the gear toward the other pulley main body side. 3. A continuously variable transmission in which a belt is stretched between a pair of variable speed pulleys disposed on an input side and an output side transmission shaft, respectively, wherein the variable speed pulleys are fixed to the corresponding transmission shafts. A fixed pulley main body, a movable pulley main body that forms a V groove between the fixed pulley main body and is movable in the axial direction of the transmission shaft, and a pulley around the outer peripheral surface of the pulley and between the opposing surfaces of both pulley main bodies. A resin power transmission ring having a trapezoidal cross section that is eccentrically sandwiched with respect to the main body, and a plurality of ribs that extend along the circumferential direction of the rubber belt are juxtaposed on the inner peripheral surface of the rubber belt. , The outer peripheral surface of the power transmission ring is formed with a plurality of circumferential grooves into which the ribs are fitted, and one of the variable speed pulleys adjusts the axial position of the movable pulley to set the gear ratio. Means to do The other variable speed pulley is provided with an elastic member for urging the movable pulley main body to the other side, and a torque cam mechanism for urging the movable pulley main body to the fixed pulley main body side in accordance with an increase in transmission torque. A continuously variable transmission characterized in that 4. The means for adjusting the axial position of the movable pulley main body includes: an inertial member for increasing the turning diameter by centrifugal force to push the movable pulley main body toward the other pulley main body; and a space for accommodating the inertial member. The continuously variable transmission according to claim 3, further comprising a member that is partitioned between the movable pulley and the main body so as to become narrower outward in the radial direction. 5. The elastic member is interposed between a receiving member fixed to a transmission shaft and a movable pulley main body, and the torque cam mechanism is formed on one of the receiving member and the movable pulley main body. The continuously variable transmission according to any one of claims 2 to 4, comprising a groove formed on the other side and a shaft member formed on the other side and guided on an inner surface of the groove.