JP5364545B2 - Flat belt and belt-type continuously variable transmission including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat belt 3 capable of surely preventing vertical tearing, and a belt type continuously variable transmission 1 using the same. <P>SOLUTION: The flat belt 3 includes: a body 31 with a transmission surface, which is formed into a V-shape in cross section by being formed of inclined two inclined surfaces 30, 30; a tensile body layer 32 constituted of tensile bodies 34 buried inside the body 31 and giving tensile strength to the body 31; and a reinforcing layer 33 for reinforcement relative to the width direction of the body 31. The tensile body layer 32 and the reinforcing layer 33 are arranged adjacently in the thickness direction of the body 31. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The technique disclosed herein is a flat belt suitable for a belt-type continuously variable transmission that is wound around a conical pulley and changes the gear ratio steplessly by changing its travel position in the direction of the pulley rotation axis. The present invention relates to a belt and a belt-type continuously variable transmission including the belt.

  For example, Patent Document 1 discloses a belt-type continuously variable transmission that includes a pair of drive and driven cone pulleys, arranges them in opposite directions, and wraps a flat belt between the pair of cone pulleys. It is disclosed. In this continuously variable transmission, since the diameter of the pulley around which the flat belt is wound is changed by reciprocating the flat belt in the pulley width direction, it is possible to change the gear ratio steplessly. . In this continuously variable transmission, the transmission surface of the flat belt is configured by two inclined surfaces corresponding to the inclination of the pulley surface, and the two inclined surfaces of the flat belt are inclined in opposite directions. The belt transmission efficiency is improved by abutting against the pulley surface of the driven cone pulley.

Japanese Utility Model Publication No. 37-6739

  By the way, as a result of examination by the inventors of the present application, it has been found that in a continuously variable transmission as disclosed in the above-mentioned patent document, a flat belt is easily damaged by vertical tearing. Therefore, as a result of repeated studies by the inventors of the present application, such flat belt breakage is constituted by two inclined surfaces on the transmission surface of the flat belt. It has been found that the contact is made only in the region, and this is due to this unique transmission mode in which the contact sides of the driving pulley and the driven pulley are opposite. In other words, non-uniform tension acts on the flat belt in the width direction of the belt, and as a result, a pulling force acts on the flat belt in the width direction. In the worst case, the flat belt is damaged by vertical tearing. It will end up.

  The technology disclosed herein has been made in view of the above points, and an object thereof is to provide a flat belt capable of reliably preventing vertical tearing and a belt-type continuously variable transmission including the same. There is to do.

  Conventionally, for the purpose of increasing the strength in the width direction of the flat belt, a so-called braided fabric and a reinforcing layer containing short fibers oriented in one direction have been provided on the flat belt. The inventors of the present application paid attention to the provision of such a reinforcing layer even in the flat belt for the belt type continuously variable transmission. However, for the index for maximizing the reinforcing effect of the reinforcing layer, Had no knowledge. Accordingly, the inventors of the present application have found an optimum configuration of the reinforcing layer that can sufficiently exert the reinforcing effect by repeating numerical analysis and experiments.

  Specifically, the flat belt disclosed herein is constituted by two inclined surfaces, so that a main body having a transmission surface having a V-shaped cross section and a tensile member embedded in the main body. A tensile body layer configured by a body and imparting tensile strength to the main body; and a reinforcing layer provided in the main body and reinforcing in the width direction of the main body, the tensile body layer and the The reinforcing layer is disposed close to the thickness direction of the main body.

  That is, according to the study by the inventors of the present application, when the tensile body layer and the reinforcing layer are arranged at the same position with respect to the thickness direction of the belt, the reinforcing effect by the reinforcing layer, in other words, the longitudinal tear preventing effect is maximized. Turn into. Therefore, in practice, since the tensile body layer and the reinforcing layer cannot be arranged at the same position, the tensile body layer and the reinforcing layer can be arranged as close as possible to the thickness direction of the belt. This is advantageous in obtaining a reinforcing effect by the reinforcing layer, in other words, an effect of preventing vertical tearing.

  The tensile body layer and the reinforcing layer may be substantially in contact with each other.

  The reinforcing layer may be disposed closer to the transmission surface than the tensile body layer. According to the study by the inventors of the present application, when the transmission surface side and the back surface side of the belt sandwiching the tensile body layer are compared, the reinforcement layer is more effective when disposed on the transmission surface side. It turned out to be even higher.

The tensile stiffness in the width direction of the reinforcing layer, wherein it is configured to 1/100 or more tensile stiffness in the longitudinal direction of the tension member.

  The higher the tensile rigidity in the width direction of the reinforcing layer, the higher the reinforcement effect of the main body, but according to the study by the present inventors, the tensile rigidity in the width direction of the reinforcing layer is the tensile rigidity in the longitudinal direction of the tensile body. On the other hand, when it is smaller than 1/100, it was found that the reinforcing effect is greatly reduced. For this reason, in order to effectively obtain the reinforcing effect, the tensile rigidity in the width direction of the reinforcing layer is preferably 1/100 or more with respect to the tensile rigidity in the longitudinal direction of the tensile body.

  The belt-type continuously variable transmission disclosed herein includes the flat belt, a conical drive pulley whose pulley surface is inclined with respect to a pulley rotation shaft, and the pulley surface of the drive pulley whose inclination direction is opposite. A belt that continuously changes the transmission gear ratio by reciprocating the drive belt and the flat belt wound around the driven pulley in the direction of the pulley rotation axis. Control means.

  As described above, the flat belt sufficiently obtains the reinforcing effect of the reinforcing layer. Therefore, when applied to a belt-type continuously variable transmission using a conical pulley, in other words, it is pulled in the width direction. In the flat belt used under the condition that the vertical tearing is likely to occur due to the action of the peeling force, it is advantageous in suppressing the occurrence of the vertical tearing.

  As described above, according to the flat belt and the belt-type continuously variable transmission, the reinforcement layer and the reinforcing layer are arranged close to each other in the thickness direction of the belt, thereby providing a sufficient reinforcing effect by the reinforcing layer. It becomes advantageous in obtaining, and the longitudinal tearing of the flat belt can be effectively suppressed.

It is a perspective view which shows schematic structure of a belt-type continuously variable transmission. It is sectional drawing of a transmission control pulley. It is a front view of a transmission control pulley. It is IV arrow line view of FIG. FIG. 4 is a view taken in the direction of arrow V in FIG. 3. It is sectional drawing of a flat belt. It is an analysis result which shows the relationship of the stress ratio which acts on a flat belt with respect to the arrangement | positioning position of a reinforcement layer. It is an analysis result which shows the relationship of the stress ratio which acts on a flat belt with respect to the tensile rigidity ratio of a reinforcement layer and a tensile body.

  Hereinafter, an embodiment of a belt type continuously variable transmission will be described with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature. FIG. 1 shows a schematic configuration of a belt type continuously variable transmission 1 (hereinafter also simply referred to as a continuously variable transmission) as an example. The continuously variable transmission 1 is driven by a drive pulley 21, a driven pulley 22, a flat belt 3 wound between the drive pulley and the driven pulley, and a back surface of the flat belt 3 so as to apply tension to the flat belt 3. And a shift control pulley 5 that can change the travel position of the flat belt 3 in the direction of the rotation axis of the pulley.

  The drive pulley 21 has a conical shape in which the pulley surface 211 is inclined with respect to the pulley rotation axis direction, and is driven to rotate around the rotation axis X1 by being connected to a drive source (not shown). It is configured.

  The driven pulley 22 is configured to be rotatable around the rotation axis X <b> 2 and, like the drive pulley 21, has a conical shape in which the pulley surface 221 is inclined with respect to the pulley rotation axis direction. Here, the inclination angle of the pulley surface 221 is the same between the driving pulley 21 and the driven pulley 22. The conical driven pulley 22 is arranged such that its rotation axis X2 is parallel to each other with a predetermined interval from the rotation axis X1 of the drive pulley 21, and the inclination direction of the pulley surface 221 is The drive pulley 21 is disposed in the opposite direction. That is, the drive pulley 21 is disposed so as to taper from the right back to the left front in FIG. 1, while the driven pulley 22 is directed from the left front to the right back in FIG. It is arranged to be tapered.

  The flat belt 3 is wound around the driving pulley 21 and the driven pulley 22, and torque is transmitted from the driving pulley 21 to the driven pulley 22 via the flat belt 3. Although the detailed configuration of the flat belt 3 will be described later, as shown in FIG. 6, the flat belt 3 has two transmission surfaces (lower surfaces in FIG. 6) that are in contact with the pulley surfaces of the pulleys 21 and 22. 30, 30. The two inclined surfaces 30, 30 are configured to be inclined at the same inclination angle from both sides in the pulley width direction downward toward the center thereof, whereby the transmission surface of the flat belt 3 is flat V-shaped. Is made. Here, the inclination angle of each inclined surface 30 is set to an angle corresponding to the inclination angle of the pulley surfaces 211 and 221 of the driving and driven pulleys 21 and 22, whereby the flat belt 3 has one inclined surface 30. Is in contact with the pulley surface of the drive pulley 21, while the other inclined surface 30 is in contact with the pulley surface of the driven pulley 22, which is advantageous in improving belt transmission efficiency. The flat belt 3 having a V-shaped transmission surface as described above is also a belt that does not exhibit a wedge effect on a pulley such as a V-belt and travels only by friction with the pulley. Then, it will be described in a definite manner that it is the same as a general flat belt having a flat transmission surface.

  As described above, the shift control pulley 5 has a function of changing the traveling position of the flat belt 3 in the pulley rotation axis direction. For example, Japanese Patent Application Laid-Open No. 2006-10072, which is an earlier application by the applicant of the present application. It is possible to adopt the same configuration as the pulley disclosed in the above. In this embodiment, the shift control pulley 5 is specifically configured as shown in FIGS. In FIG. 3, the thickness of the flat belt 3 is omitted.

  The transmission control pulley 5 includes a cylindrical main body 51 on which the flat belt 3 is wound, a cylindrical shaft member 53 that rotatably supports the main body 51 around the pulley rotation axis C1 by a bearing 52, A support member that supports the shaft member 53 together with the main body 51 so as to be swingable around a pivot C2 described later is configured.

  The support member includes a support rod 54 and a pin 55 fixed to the support rod 54. Of these, the base end portion of the support rod 54 is not shown in the figure, but is supported by being attached to a moving mechanism that reciprocally moves the entire speed change control pulley 5 including the support rod 54 in the direction of the pulley rotation axis C1. . There is no restriction | limiting in particular in the structure of a moving mechanism, As an example, it is possible to employ | adopt the vacuum cylinder currently disclosed by the said Unexamined-Japanese-Patent No. 2006-10072. As the power source, various devices such as a motor, a linear motor, a solenoid, and a hydraulic cylinder can be used.

  As shown in FIG. 2, the distal end portion of the support rod 54 is inserted into a cylindrical shaft member 53. As shown in FIG. 3, the tip of the support rod 54 is formed by cutting a portion corresponding to the diameter direction of the cross-section circular rod into a D shape. Sliding surfaces 541 and 541 are formed. Therefore, the distal end portion of the support rod 54 includes flat sliding surfaces 541 and 541 facing each other and arcuate surfaces on both sides connecting the side edges of the sliding surfaces 541 and 541 and has a substantially rectangular cross-sectional shape. It is made into a shape.

  On the other hand, the cylindrical hole of the shaft member 53 has a substantially rectangular cross section corresponding to the cross sectional shape of the tip of the support rod 54. That is, the flat sliding surfaces 531 and 531 with which the sliding surfaces 541 and 541 of the support rod 54 slidably contact each other are opposed to the inner surface of the shaft member 53 as shown in FIG. In addition, circular arc surfaces on both sides connecting both side edges of the sliding surfaces 531 and 531 are formed.

  The pin 55 is fitted into a through hole formed at the tip of the support rod 54, and both ends of the pin 55 are fitted into support holes formed in the shaft member 53. More specifically, the pin 55 is fixed to the support rod 54 so as to be orthogonal to the sliding surface 541 of the support rod 54, and as shown in FIG. It is arranged at a position near the center in the width direction.

  Thus, the shaft member 53 swings together with the main body 51 around the pin 55 between the arc surfaces on both sides of the tip of the support rod 54 and the arc surfaces on both sides of the cylindrical hole of the shaft member 53. Clearances 56, 56 that allow Thus, as described above, the main body 51 is supported so as to be rotatable about the pulley rotation axis C1 and to be swingable about the pivot C2 orthogonal to the pulley rotation axis C1.

  As described above, the transmission control pulley 5 is disposed so as to apply tension to the flat belt 3 by being pressed against the back surface of the flat belt 3 between the driving pulley 21 and the driven pulley 22. ing. Further, as shown in FIG. 3, the transmission control pulley 5 is configured such that the direction of the pivot C2 is inclined by an angle α toward the front side of the belt traveling direction A with reference to the direction of the axial load L acting on the shaft member 53. Arranged. In this state, the shift control pulley 5 reciprocates in the direction of the pulley rotation axis C1 by the movement mechanism (not shown) as described above (see the phantom line arrow in FIG. 1).

  The speed change operation of the belt type continuously variable transmission 1 will be described with reference to the drawings. First, as shown by a solid line in FIG. 1, it is assumed that the flat belt 3 is wound around the drive pulley 21 and the driven pulley 22 at a substantially central position in the pulley width direction. At this time, the speed change control pulley 5 is at a position where the flat belt 3 is wound, more specifically, at a position where the pin 55 is positioned at the approximate center in the width direction of the flat belt 3 as shown by a solid line in FIG. Has been placed. From this state, when the shift control pulley 5 is moved to one side in the direction of the pulley rotation axis C1, that is, the left front side in FIG. 1 and the left side in FIGS. 4, the flat belt 3 is relatively displaced from the center position of the main body 51 to the end in the width direction (the right end in FIG. 4). Due to this offset, the axial load L acting on the main body 51 is shifted from the position of the pin 55 to one side of the main body 51 and acts on the shaft member 53. Here, since the pin 55 (the pivot C2) is inclined by the angle α with respect to the direction of the axial load L, a rotational moment about the pin 55 acts on the shaft member 53, and the shaft member 53 is Together with the main body 51, it is rotationally displaced around the pin 55 (the pivot axis C2). As a result, as shown in phantom lines in FIG. 4, the main body 51 has an end on the side (right side in FIG. 4) from which the flat belt 3 is relatively offset (on the left side in FIG. 4) Compared to FIG. 5, the belt belt 3 is obliquely crossed so as to be on the front side in the belt running direction A. Further, as indicated by a phantom line in FIG. The end on the incoming side (right side in FIG. 5) is inclined so as to be higher in the direction of the axial load L than the end on the opposite side (left side in FIG. 5). As a result, the flat belt 3 is acted on by a force for returning the offset due to the main body 51 being in an oblique state and a returning force due to the inclination of the main body 51. To move to the position of the pin 55 (see arrows in FIGS. 4 and 5).

  That is, when the speed change control pulley 5 is moved relative to the flat belt 3, a force that moves the flat belt 3 to the position of the pin 55 on the main body 51 acts on the flat belt 3. Moves following the speed change control pulley 5 and changes its travel position. By changing the running position of the flat belt 3 from the approximate center position in the pulley width direction of the driving and driven pulleys 21 and 22 to the left front side in FIG. Is smaller than the initial diameter and the diameter of the driven pulley 22 is larger than the initial diameter.

  On the contrary, when the transmission control pulley 5 moves to the other side in the pulley rotation axis C1 direction, that is, the right rear side in FIG. 1, the main body 51 of the transmission control pulley 5 is rotationally displaced in the opposite direction to the above. Therefore, the flat belt 3 follows the shift control pulley 5 and moves to the right back side in FIG. As a result, the diameter of the drive pulley 21 around which the flat belt 3 is wound is large and the diameter of the driven pulley 22 is small, so that the speed ratio is increased. Thus, in the belt-type continuously variable transmission 1, the transmission control pulley 5 changes the travel position of the flat belt 3, whereby the transmission ratio is changed steplessly.

  Note that the configuration of the speed change control pulley 5 is not limited to the above-described configuration. For example, as in the pulley disclosed in Japanese Patent Application Laid-Open No. 2006-9987, which is an earlier application of the present applicant, On the other hand, a structure that reciprocally moves in the direction of the pulley rotation axis is adopted, or a structure in which the main body is forcibly tilted by a solenoid, as in the pulley disclosed in Japanese Patent Application Laid-Open No. 2004-144245. You may do it. Furthermore, the means for changing the travel position of the flat belt 3 is not limited to using the pulley as described above, and various other means can be employed.

  Next, the configuration of the flat belt 3 will be described in more detail with reference to FIG. The flat belt 3 is a laminated flat belt 3 in which a tensile body layer 32 and a reinforcing layer 33 are provided on a main body 31 made of, for example, a rubber composition. The tensile body layer 32 is configured by embedding a cord as a tensile body 34 (heart body) in the main body 31 in a spiral shape at a predetermined pitch in the width direction, for example. Is a so-called cord flat belt. The tensile body layer 32 is disposed, for example, on the pitch line in the belt thickness direction.

  The reinforcing layer 33 is a layer for increasing the strength in the width direction and thereby preventing the occurrence of vertical tearing of the flat belt 3. As described above, the transmission surface of the flat belt 3 is constituted by the two inclined surfaces 30, 30. Only one inclined surface 30 is provided for the driving pulley 21, and the other is provided for the driven pulley 22. Since only the inclined surface 30 is in contact with the drive and driven pulleys 21 and 22 only in the half region in the width direction, the contact region is opposite to the drive and driven pulleys 21 and 22. It becomes a unique transmission form. As a result, a non-uniform tension is applied to the flat belt 3 in the width direction, and a force is generated to peel the cords 34 of the flat belt 3 from each other in the width direction. This causes a vertical tear of the flat belt 3. Therefore, in the flat belt 3, the longitudinal layer is prevented by providing the reinforcing layer 33. As the reinforcing layer 33, various configurations can be adopted. For example, the reinforcing layer 33 may be configured by a so-called bamboo woven fabric, or by a rubber layer mixed with short fibers oriented in one direction. The reinforcing layer 33 may be configured.

  The most characteristic point of the flat belt 3 is that the tensile body layer 32 and the reinforcing layer 33 are close to each other in the thickness direction of the belt. This is based on the knowledge that the reinforcing effect of the reinforcing layer 33 is enhanced by bringing the tensile body layer 32 and the reinforcing layer 33 close to each other in the thickness direction. This point will be described based on numerical analysis results and experimental results performed by the present inventors. FIG. 7 is a diagram showing a change in the stress ratio acting on the flat belt 3 when the relative position of the reinforcing layer 33 with respect to the tensile body layer 32 is changed in the thickness direction, which is obtained by performing numerical analysis. . The stress ratio here is the ratio of the stress values generated when the reinforcing layer is provided, with respect to the maximum stress acting in the width direction of the belt, based on the stress value generated when the reinforcing layer is not provided. Therefore, the lower the stress ratio, the higher the reinforcing effect of the reinforcing layer 33. Here, 0 (mm) on the horizontal axis means that the position of the reinforcing layer 33 is located at the same position in the thickness direction as the position of the tensile body layer 32, and a positive value indicates that the reinforcing layer 33 The position is closer to the back side of the belt than the position of the tensile body layer 32, and a negative value means that the position of the reinforcing layer 33 is closer to the belt transmission surface than the position of the tensile body layer 32. According to the figure, when the position of the reinforcing layer 33 is located at the same position in the thickness direction as the position of the tensile body layer 32, the reinforcing effect by the reinforcing layer 33 is the highest, and the position of the reinforcing layer 33 is resistant. It can be seen that the further away from the position of the tension layer 32, the lower the reinforcing effect. Therefore, it is desirable that the position of the reinforcing layer 33 and the position of the tensile body layer 32 be the same, but in the actual flat belt 3, it is not possible to provide the reinforcing layer 33 and the tensile body layer 32 at the same position. Since it is possible, it is preferable to arrange the reinforcing layer 33 and the tensile body layer 32 as close as possible. For example, the amount of displacement between the reinforcing layer 33 and the tensile body layer 32 (see the one-dot chain line in FIG. 6) is (t1 + t2) / 2 when the thickness of the tensile band is t1 and the thickness of the reinforcing layer is t2. The coefficient α may be set to an appropriate value of 1 or more, for example, as (t1 + t2) / 2 × α. Possible values of α may be, for example, 1 ≦ α <2, or 1 ≦ α <1.5, or 1 ≦ α <1.3. When α = 1 and the amount of deviation is (t1 + t2) / 2, the reinforcing layer 33 and the tensile body layer 32 are substantially in contact with each other.

  Further, according to the figure, since the reduction side of the reinforcing effect is smaller on the minus side, the reinforcing layer 33 is disposed on the belt transmission surface side than the tensile body layer 32 as illustrated in FIG. Is preferred.

  FIG. 8 shows the reinforcing layer 33 when the ratio between the tensile stiffness in the width direction by the reinforcing layer 33 and the tensile stiffness in the longitudinal direction by the tensile body layer 32 (that is, the lateral stiffness / longitudinal stiffness ratio) is changed. This shows the change in the reinforcing effect (change in pressure ratio). According to the figure, it can be seen that the reinforcing effect is enhanced when the tensile rigidity in the width direction by the reinforcing layer 33 is high, whereas the reinforcing effect is greatly reduced when the rigidity ratio is smaller than 0.01. From this result, it is preferable that the tensile rigidity in the width direction by the reinforcing layer 33 is 1/100 or more with respect to the tensile rigidity in the longitudinal direction by the tensile body layer 32, and the tensile body is satisfied so that this relationship is satisfied. The configuration of the layer 32 and its material (arrangement of the tensile body 34 and its material) and the configuration of the reinforcing layer 33 and its material may be determined.

  Thus, in the flat belt 3, the configuration and arrangement of the reinforcing layer 33 can be optimized to obtain a sufficient reinforcing effect in the belt width direction. It is. In particular, in the flat belt 3 used in a condition where the transmission surface is composed of two inclined surfaces 30 and 30 and is easily wound by being wound around the conical pulleys 21 and 22, occurrence of vertical tearing is caused. It is effective in preventing effectively. Further, by sufficiently reinforcing in the width direction, the tensile stress in the width direction acting on the tensile belt layer 32 of the flat belt 3 is reduced, and unevenness in the tension distribution in the width direction of the flat belt 3 is alleviated. The Accordingly, an improvement in the durability life of the flat belt 3 can be expected.

  As described above, the flat belt disclosed herein is useful particularly as a flat belt used in a belt-type continuously variable transmission or the like constituted by a conical pulley.

DESCRIPTION OF SYMBOLS 1 Belt type continuously variable transmission 21 Drive pulley 22 Driven pulley 3 Flat belt 30 Inclined surface 31 Main body 32 Tensile body layer 33 Reinforcement layer 34 Tensile body 5 Transmission control pulley (belt control means)

Claims (4)

A main body having a transmission surface having a V-shaped cross section by being constituted by two inclined surfaces inclined,
A tensile body layer constituted by a tensile body embedded in the main body and imparting tensile strength to the main body;
A reinforcing layer provided in the main body and reinforcing in the width direction of the main body,
The tensile body layer and the reinforcing layer are arranged close to the thickness direction of the main body ,
The flat belt in which the tensile rigidity in the width direction of the reinforcing layer is set to 1/100 or more of the tensile rigidity in the longitudinal direction of the tensile body . The flat belt according to claim 1,
The flat belt in which the tensile body layer and the reinforcing layer are disposed substantially in contact with each other. The flat belt according to claim 1 or 2,
The reinforcing layer is a flat belt disposed closer to the transmission surface than the tensile body layer. The flat belt according to any one of claims 1 to 3 ,
A conical drive pulley whose pulley surface is inclined with respect to the pulley rotation axis;
A conical driven pulley arranged such that the direction of inclination is opposite to the pulley surface of the drive pulley;
Belt-type continuously variable transmission comprising belt control means for continuously changing the transmission gear ratio by reciprocating the flat belt wound around the drive pulley and the driven pulley in the pulley rotation axis direction. Machine.

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