JPS59113338A - Transmission belt - Google Patents

Abstract

PURPOSE:To improve transmission efficiency by making the radius of curvature of the inner peripheral surface of a portion of a circular member wrapped round a rotary pulley equal or less to the radius of curvature of a curve connecting contact points among blocks at that portion. CONSTITUTION:A circular transmission belt 14 is stretched between rotary pulleys 10, 11 respectively fixed to an input shaft 6 and an output shaft 8. The transmission belt 14 is multi-layer flexible circular body having a substantially inner peripheral surface 22 and includes a pair of metal hoops 20 disposed paralflatlel to each other and a lot of blockes 26 continuously disposed along the hoops and provided with contact surfaces 24 contacting the above inner peripheral surface 22. In this case, at portions of the blocks 26 and the metal hoops 20 wrapped round the rotary pulley 12, the radius of curvature Rf of the inner peripheral surface 22 of the metal hoop 20 is made smaller than the radius of curvature Rb of a curve smoothly connecting the contact points among the blocks 26. In this arrangement, transmission efficiency can be increased in an area of a large speed ratio of the rotary pulleys 11, 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmission belt that is passed between rotating pulleys to transmit rotational force, and particularly relates to a transmission belt that has high transmission efficiency.

It comprises a ring and a number of blocks arranged in a row along the ring in contact with the inner peripheral surface of the ring, and the hook is passed between rotating pulleys to transmit rotational force. Conductive belts are known. Although such a transmission belt has excellent transmission ability, flexibility, and durability, there is power consumption due to sliding between the block and the ring belt, and sufficient transmission efficiency has not always been obtained. . In particular, the effective diameter can be changed by changing the distance between a pair of plates with opposing conical surfaces.
■When transmitting rotational force when the pulley speed ratio (output rotation speed/input rotation speed) is large,
This results in a significant decrease in conduction efficiency.

With the above circumstances as a background, the inventors of the present invention have conducted various studies in order to improve the transmission efficiency of the transmission belt, and as a result, the radius of curvature of the ring band in the part wrapped around the rotating pulley has been increased compared to the conventional case. It has been found that if the ratio is also made smaller, the conduction efficiency is significantly improved in the most frequently used region where the speed ratio between the rotating pulleys is large. The present invention has been made based on the above findings.

That is, the gist of the present invention is that the radius of curvature of the inner circumferential surface of the ring in the part wound around the rotating pulley is the radius of curvature of the curve that smoothly connects the contact points between the blocks in that part. The reason is that the radius is the same or smaller.

By doing this, in the speed increasing state where the speed ratio between the rotating pulleys is large, the transmission belt 1 of the rotating pulley on the input side! ) has a large diameter (effective diameter) and the diameter (effective diameter) of the transmission belt on the output side rotating pulley is made small, so there is There is no slippage, and the angular velocity of the block and the annulus are equal, but slipping occurs between the block and the annulus at the part wrapped around the output rotating pulley, and the angular velocity of the annulus is equal to that of the block. equal to or greater than the angular velocity. Therefore, the rotational force of the input side rotating pulley is
Since the power is transmitted to the output side rotary pulley via the block and also transmitted to the output side rotary pulley via the ring, higher transmission efficiency can be obtained compared to the conventional case.

Incidentally, in a conventional transmission belt in which the radius of curvature of the ring band at the part wrapped around the rotating pulley is greater than the radius of curvature of the curve that clearly connects the contact points between the blocks in that part, the speed increase state with a large speed ratio In that case,
There is no slippage between the block wrapped around the input side rotating pulley with a large effective diameter and the ring band, and their angular velocity is the same, but in the part wrapped around the output side rotating pulley with a small effective diameter, Slip occurs between the block and the annulus, and the angular velocity of the block becomes greater than the angular velocity of the annulus. In this state, the output side rotary pulley is rotated together with the block, so the ring whose angular velocity is smaller than the block drives the output side rotary pulley in a relatively opposite direction via the block, and the overall The conduction efficiency of the conduction belt was suppressed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below based on the drawings.

In FIG. 1, rotating pulleys 1o and 12 are attached to an input rotating shaft 6 and an output rotating shaft 8 of a variable transmission (not shown), and an annular transmission belt 14 is hung between these rotating pulleys IJI0 and 12. is passed to the input side rotating shaft 6
The rotational force is transmitted to the output rotating shaft 8. This variable transmission usually has a speed ratio (output side rotating shaft 8
It is mainly used in a speed-up state where the number of revolutions (0 revolutions/number of revolutions of input side rotating shaft 6) is large. The rotating pulley j0.12 has a pair of side plates 16.16 with opposing conical surfaces.
and 18.18, respectively, and the effective diameter of the groove formed between the side plates 16.16 and 18.18 by changing the spacing between the side plates 16.16 and 18.18 (the effective diameter of the The opening diameter) has been changed to provide a stepless gear ratio. In FIG. 1, one side plate of each pair of side plates 16.16 and 18.18 is shown cut away.

The conductive belt 14, as shown in detail in FIGS. 2 and 3, is a multi-layered visibility ring having a generally flat inner circumferential surface 22 and comprising a pair of parallel metal hoops 20,20 and the metal hoops 20,20. The inner peripheral surface 2 is arranged in series along the hoop 20.
2, and a plurality of blocks 26 each having a contact surface 24 in contact with the block 2. Block 26 is made of metal and ceramic.

It is a rectangular plate-like body made of a highly rigid material such as fiber-reinforced synthetic resin (CFRP), and is stacked along the metal hoop 20. Both end surfaces 28 in the longitudinal direction of the pro-tsuku 26 are sloped surfaces that approach each other toward the inner circumference of the transmission belt 14 so as to fit into the V grooves of the rotary pulleys 10 and 12. . That is, the width dimension of the block 26 in the longitudinal direction becomes slightly narrower toward the inner circumferential side. Further, a pair of notches 30 parallel to the longitudinal direction are formed in the block 26 from the longitudinal center portions of both end faces 28 toward the center of the block 26, and the metal hoops 20 are respectively fitted into the notches 30. There is. In other words, the block 26 is an H-shaped plate piece. Therefore, since a predetermined tension is normally applied to the metal hoop 20, the inner peripheral surface of the metal hoop 20
The inner peripheral surface 22 is one of the inner wall surfaces of the notch 30 facing each other.
It is brought into sliding contact with a contact surface 24 opposite to. Note that each of the contact surfaces 24 is formed with a curved surface having a smaller radius of curvature than the minimum radius of curvature of the metal hoop 20.

The thickness of the block 26 is the same from the outer circumferential side to the position in front of the notch 30, but the thickness decreases linearly from the near side to the inner circumferential side. That is, one adjacent surface 32 of the block 26 is a flat surface, and the other adjacent surface is a parallel surface 34 parallel to one adjacent surface 32 located on the outer peripheral side from the front position, and a parallel surface 34 parallel to this parallel surface 34. Subsequently, the sloped surface 36 linearly approaches one adjacent surface 32 toward the inner circumferential side. Therefore, the transmission belt 14 is connected to the rotating pulley 10 or 1.
2, the boundary point between the parallel surface 34 and the inclined surface 36 contacts one adjacent surface 32 of the adjacent block 26, and the rotation of the rotary pulley 10 or 12 smoothly connects the contact point. A radius of curvature (belt pitch diameter Rb) concentric with the axis is formed. Therefore, since the notch 30 is formed on the end surface 28 of the block 26 at a position on the inner peripheral side of the boundary point between the parallel surface 34 and the inclined surface 36, the belt pitch diameter Rb is determined by the metal fitted into the notch 30. hoop 2
The radius of curvature Rf of the inner circumferential surface 22 of 0 is made larger than the radius of curvature Rf of the inner circumferential surface 22 of 0.

The effects of this embodiment will be explained below.・Rotating pulley 1
In a state where the speed ratio of 0' and 12 is large and the output rotation speed of the rotary pulley I2 with a small effective diameter is large relative to the input rotation speed of the rotary pulley 1o with a large effective diameter, the transmission belt 14 is The state shown in Figure 4 is reached. In addition, the conduction heald 1 in FIGS. 4 to 6 in the following explanation
4 is a metal hoop 20 in order to facilitate the explanation of the operation.
8 indicating the inner circumferential surface 22 of the block 26 and a line B smoothly connecting the contact point between the blocks 26.

In the speed increasing state as described above, the block 26 and the metal hoop 20 at the part wrapped around the rotary pulley 10
The contact area between them is large (because no slipping occurs between them, the angular velocity ωb of the block 26 and the angular velocity ωf of the metal hoop 20 are approximately the same), but the part wrapped around the rotating boob IJ12 block 26 and metal hoop 20 in
means that the radius of curvature Rf of the inner peripheral surface 22 of the metal hoop 20 is the radius of curvature R of the curve that smoothly connects the contact points between the blocks 26.
Since it is smaller than b, slippage occurs between the block 26 and the metal hoop 20, and the angular velocity ωf of the metal hoop 200 becomes larger than the angular velocity ωb of the block 260. Therefore, since the metal hoop 20 relatively drives the rotating boob IJ10 via the block 26 on the rotating boob 112 side, the rotational force of the rotating pulley 10 is transmitted to the rotating pulley 12 by the compressive force of the block 26. Not only is it transmitted by the tension of the metal hoop 20,
The conduction efficiency of the conduction belt 14 is greatly improved. That is, the so-called tension side tension S1 of the metal hoop 20 in FIG. 4 is larger than the so-called slack side tension S2, and the rotational force is transmitted by the difference between the tensions S1 and 82.

Incidentally, when the radius of curvature Rf of the inner circumferential surface 22 of the conventional metal hoop 20 is made larger than the radius of curvature Rb of the curve smoothly connecting the contact points between the blocks 26, as shown in FIG. As shown in FIG.
The angular velocity ωb of the metal hoop 20 is made larger than the angular velocity ωb of the metal hoop 20. At this time, the rotating pulley 12 is moved to the block 26
As a result, the metal hoop 20 is rotated in the opposite direction relative to the rotating pulley 12, and the rotational force of the rotating pulley 10 transmitted to the rotating pulley 12 via the block 26 causes the metal hoop 20 to rotate. The relative rotational force in the opposite direction is transmitted to the rotary pulley 12 via the block 26 and canceled out, thereby limiting the transmission efficiency. That is, the so-called tension side tension 81 of the metal hoop 20
is made smaller than the so-called slack side tension S2, so the rotary pulley 12 receives a rotational force in the opposite direction due to the difference between the tension S1 and the tension S2.

On the other hand, when the speed ratio between the rotary boolean 1J10 and the rotary pulley 12 is reduced and the rotational speed of the rotary pulley 10 is reduced and transmitted to the rotary boolean IJ12,
As shown in FIG. 6, the transmission belt 14 is in a state where it is passed over the rotating pulley 10 with a reduced effective diameter and the rotating pulley 12 with an enlarged effective diameter. In such a state, the angular velocity ω of the block 26 in the portion of the transmission belt 14 that is wrapped around the rotary boob IJ12 on the output side is
It is assumed that f and the angular velocity ωb of the metal hoop 20 are the same,
In the portion of the conductive belt 14 wrapped around the input-side rotating boob IJ10, the angular velocity ωb of the metal hoop 20 is made larger than the angular velocity ωb of the block 26. Therefore, the rotational force of the rotary boob IJ10 is transmitted to the rotary pulley 12 via the block 26, while the rotational force of the rotary boob IJ12 on the output side is returned to the rotary boob IJ10 via the metal hoop 20, in a power circulation state. becomes. Therefore, a part of the rotational force of the rotary pulley 10 transmitted to the rotary pulley 12 via the block 26 is returned to the rotary pulley 10 via the metal hoop 20 again, so that the transmission efficiency of the transmission belt 14 is limited. state. However, such a deceleration state is extremely rare in practice, and the transmission belt 14 is mainly used in the above-mentioned speed increase state, so that higher transmission efficiency can be obtained than in the past.

In this way, according to the present embodiment, in the conductive belt 14 at the portion wound around the rotary pulleys 10 and 12, the radius of curvature Rb of the curve that smoothly connects the contact points between the blocks 26 is within the metal hoop 20. It is thicker than the radius of curvature Rf of the circumferential surface 22 (because it is, when the conduction heald 14 is wound around the rotating pulleys 10 and 12 in the speed-up state), high conduction efficiency of the conduction belt 14 is obtained. be.

Further, according to this embodiment, the end surface 28 of the block 26 is
Holding the notch 30 for fitting the metal hoop 20,
Since they are provided on the inner and outer circumferential sides, the surface pressure of the end surface 28 against the side plate 16 and the guard plate 18 is reduced, and wear of the end surface 28 is not only suppressed, but also the rotating boob IJ 10.12 When the block 26 is held in the groove, the end face 28 of the Miprosock 26 is supported by the side play 1-16 or 18 on the inner and outer sides of the metal hoop 20, so that the frictional force between the blocks 26 and The posture of the block 26 becomes stable regardless of the frictional force between the block 26 and the metal hoop 20, and compared to the conventional case in which the end surface 2B was mainly provided on the inner circumferential side of the metal hoop 20, the pro-7 There is an advantage that the reduction in conduction efficiency caused by variations in the posture of the steering wheel 26 is completely eliminated.

In the above embodiment, in order to maintain the posture of the block 26, tension is applied to the metal hoop 20.
It is desirable to minimize the gear knobs between the blocks 26 when the transmission belt 14 is in operation. For this reason, the metal hoop 20 is
When fitting the metal hoop 20 into the notch 30 of the metal hoop 20, the metal hoop 20 can be press-fitted while applying tension, but the following method may also be used.

That is, as shown in No. 7 and 1, a metal hoop 2 is placed between the blocks 26 of the conductive belt 14 that has been assembled.
A block 40 is driven in to apply tension to the 0. The block 40 has a T-shaped plate shape in which the inner circumferential portion of the notch 30 in the block 26 described above is cut off,
A stop 74 is provided on the protrusion 42 protruding toward the inner circumferential side.
A through hole 46 is formed for inserting 4.

Such a block 40 is driven between the blocks 26 until its protrusion 42 passes between the metal hoops 20, and a stop pin 44 is inserted into a through hole 46 formed in the protrusion 42 on the inner peripheral side of the metal hoop 20. If you do it like this,
Tensioning of the metal hoop 20 is very easily applied.

Although the embodiment of the present invention has been described above based on the drawings, the present invention can also be applied to other aspects.

For example, in the above-described embodiment, in the portion of the conductive belt 14 wrapped around the rotating boo U 10 or 12, the radius of curvature Rf of the inner peripheral surface 22 of the metal hoop 20 smoothly connects the contact points between the blocks 26. radius of curvature Rb of the curve
Although the radius of curvature is made smaller than Rb, it is sufficient if it is equal to or smaller than the radius of curvature Rb.

Further, although the end face 28 of the block 26 is provided on the inner circumferential side and the outer circumferential side of the metal tool 120, it may be provided only on the inner circumferential side as in the conventional case.

Further, the metal tool 120 may be composed of a single layer of metal, and its material may be not only metal but also resin, or may be composed of metal or resin fibers. be.

Furthermore, the conductive belt may be constructed by forming the block 26 into a U-shaped plate having a groove in the thickness direction that opens on the outer circumferential side, and fitting a single metal hoop into the groove. Needless to say.

It should be noted that the above is just one embodiment of the present invention,
The present invention can be modified in various ways without departing from its spirit.

[Brief explanation of drawings]

FIG. 1 is a front view showing a state in which a transmission belt according to an embodiment of the present invention is hung between two rotating pulleys. Second
3 are a perspective view and a front view, respectively, of a portion of the conductive heald of FIG. 1. FIG. 4 is an explanatory diagram of the operation of the transmission belt of FIG. 1 in a speed increasing state. FIG. 5 is an explanatory diagram of the operation of a conventional transmission belt. FIG. 6 is a diagram corresponding to FIG. 4 in a decelerated state. FIG. 7 is an explanatory diagram showing an example of a method of applying tension to a metal hoop. 10, +2: Rotating pulley 14: Transmission belt 20.2 (
l Metal hoop (ring) 22: Inner circumferential surface 26: Blossom Rb: Helmet diameter Rf: Radius of curvature of inner circumferential surface Applicant: Toyota Motor Corporation Fig. 1 Fig. 5 Fig. 4 Fig. 6

Claims (1)

[Claims] A ring belt and a large number of blocks arranged in series along the ring belt in contact with the inner circumferential surface of the ring belt, and a hook between the rotating pulleys is provided. In a transmission belt that transmits rotational force, the radius of curvature of the inner circumferential surface of the ring band in the part wrapped around the rotating pulley is the radius of curvature of a curve that smoothly connects the contact points between the blocks in that part. A conduction belt characterized by having an equal or smaller radius.