JP2005249092A - Pulley for driving belt and belt transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a driving belt 3 from meandering. <P>SOLUTION: In a pulley, a pulley main body 5 is supported by a shaft member 11 rotatably around its rotational center axis C1. The pulley main body 5 and the shaft member 11 are supported by a pivot shaft C2 swingably around it which is tilted forward in a running direction of the driving belt 3 at a tilt angle α. When the driving belt 3 is moved to one side, the pulley main body 5 is tilted to produce a height difference at least in the direction of the axial load, thereby producing a force to return the driving belt 3 to its original position. The direction of tilt of the pivot shaft C2 can be changed by a switching means 20 corresponding to the change of the running direction of the belt. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transmission belt pulley and a belt transmission device.

  In a transmission device using a flat belt, the flat belt may meander while the vehicle travels, or may travel offset by moving toward one side of the pulley. This is because the flat belt is more sensitive to changes in the components of the transmission device, such as the displacement of the pulley shaft from its normal position, the deflection of the pulley shaft due to changes in shaft load, and the vibration of the pulley, compared to other transmission belts. It is. When such meandering / offset running occurs, the flat belt comes into contact with the flange of the flat pulley, causing fuzz on the side surface of the flat belt and fraying of the core.

  In order to solve this problem, it is known to attach a crown to the outer peripheral surface of the flat pulley (form a medium-high curved surface). There is also a proposal that the crown on the outer peripheral surface of the pulley is formed in a spherical shape centered on the rotation center of the pulley (see Patent Document 1). This is because when there is a tension difference between the left and right sides of the flat belt and the pulley shaft is tilted, and the flat belt is offset on the pulley, a rotational moment acts on the pulley due to the tension of the flat belt. By utilizing this, the inclination of the pulley shaft and the deviation of the flat belt are eliminated.

  Moreover, what formed many groove | channels in the outer peripheral surface of the flat pulley at intervals in the circumferential direction is known (refer patent document 2). In other words, the groove extends symmetrically from the center of the width of the pulley so as to form a “<” shape on both sides, and a frictional force that moves the flat belt to the center between the flat belt and the pulley. By generating the belt, meandering or deviation of the belt is prevented.

Furthermore, it is also known that guide rollers are arranged on both sides of the flat belt to restrict the travel position of the flat belt (see Patent Document 3).
Japanese Utility Model Publication No.59-45351 JP-A-6-307521 Japanese Utility Model Publication No. 63-6520

  However, when the crown is formed on the pulley, if the radius of curvature of the crown is reduced with an emphasis on the running stability of the flat belt (preventing meandering and shifting), the stress concentrates in the center of the belt width, and the belt width The whole cannot be used effectively for transmission, leading to early fatigue of the core and a reduction in transmission capability.

  Further, when the pulley crown is formed in a spherical shape centered on the rotation center of the pulley, even if the effect of preventing the transmission belt from shifting is enhanced, stress is concentrated at the center of the belt width by the pulley crown. Still remains.

  If the flat pulley is grooved as described above, the manufacturing cost of the flat pulley increases, and it is difficult to reliably prevent meandering and shifting of the flat belt only by the groove processing.

  Furthermore, if a method of restricting the running position by arranging guide rollers or the like on both sides of the flat belt, both sides of the flat belt will always come into contact with such a restricting member. Line fraying is likely to occur. Therefore, it is necessary to specially process the flat belt for preventing them, which is disadvantageous in reducing the production cost of the flat belt.

  For these reasons, flat belt transmissions are not fully utilized despite the fact that they have less loss due to belt bending and very high transmission efficiency compared to other belts such as V-belts. It is.

  Therefore, the present invention can surely prevent the meandering and shifting of the flat belt and other transmission belts, so that the belt transmission device can be effectively used for various industrial machines and other devices. To do.

  The present invention displaces the pulley by utilizing the fact that the position of the axial load applied to the pulley shaft is changed by the tension of the transmission belt when the transmission belt is offset, and the transmission belt is offset and meandered. To prevent.

  That is, the transmission belt pulley of the present invention includes a pulley body around which the transmission belt is wound, a shaft member that rotatably supports the pulley body around a rotation center axis, and the shaft member together with the pulley body. An axis orthogonal to the central axis, and the axis around which the transmission belt is tilted at a predetermined tilt angle toward the front side in the direction in which the transmission belt is in contact with the pulley body and travels on the basis of the direction of the axial load applied to the shaft member And a switching means for switching the tilting direction of the pivot relative to the direction of the axial load in accordance with switching of the traveling direction of the transmission belt.

  According to this transmission belt pulley, when the transmission belt is offset on the pulley body and the axial load is shifted from the position of the pivot shaft to one side in the pulley body width direction and acts on the shaft member, A rotational moment about the pivot acts on the shaft member, and the shaft member rotates and displaces around the pivot together with the pulley body.

  Since the pivot is tilted at a predetermined tilt angle toward the front side in the traveling direction of the transmission belt, the pulley body is tilted so that at least the side opposite to the side where the transmission belt is offset becomes higher, thereby A force is applied to return the offset from the pulley body to the transmission belt. Therefore, the transmission belt travels at a position where the return force and the offset force are balanced.

  That is, the inclination direction of the pulley body relative to the displacement of the transmission belt corresponds to the traveling direction of the transmission belt and the inclination direction of the pivot. For this reason, when the traveling direction of the transmission belt is switched to the reverse direction, the tilting direction of the pivot is not switched to the reverse direction across the axial load direction, in other words, the tilting direction of the pivot is based on the axial load direction. If it is not on the near side in the belt running direction, when the transmission belt is offset, a force that promotes the offset is applied to the transmission belt. That is, when the tilting direction of the pivot is fixed in one direction, the traveling direction of the transmission belt is determined in one direction.

  In the pulley of the present invention, the tilting direction of the pivot is switched by the switching means in accordance with switching of the traveling direction of the transmission belt. As a result, the pivot shaft always tilts to the front side of the traveling direction of the transmission belt with respect to the direction of the axial load, and the transmission belt performs the return force in both forward and reverse rotations of the pulley. And drive at a position where the offset force balances.

  The tilt angle of the pivot is preferably set in an angle range that exceeds 0 degrees and does not exceed 90 degrees.

  When the tilt angle is 90 degrees, that is, when the pivot is orthogonal to the axial load direction, the pulley body is rotationally displaced so that the side on which the transmission belt is offset moves in the axial load direction. . In other words, when the height is seen in the axial load direction, the transmission belt is inclined such that the side from which the transmission belt is offset is low and the opposite side is high. In other words, the outer peripheral surface of the pulley body is inclined in the same manner as the crown. As a result, a return force in a direction opposite to the offset direction is applied to the transmission belt. Therefore, the transmission belt travels at a position where the return force due to the inclination of the pulley body and the offset force acting on the transmission belt due to the characteristics of the belt transmission device are balanced. Even if the transmission belt is largely displaced, the transmission belt is returned to a position where the return force and the offset force are balanced.

  When the tilt angle is less than 90 degrees, the rotational displacement of the pulley body when the transmission belt is displaced is not limited to the component in the axial load direction but also in the front-rear direction perpendicular to the axial load direction (above The component in the direction in which the transmission belt is running in contact with the pulley body is added. That is, the pulley body is not only inclined in the axial load direction but also in contact with the transmission belt in an oblique manner.

  Then, since the pivot is tilted to the near side of the belt running direction with respect to the axial load direction, when the transmission belt is deviated, the pulley body is on the side where the transmission belt is offset. It becomes the diagonal state which became the front side of the direction. By rotating the pulley body in an oblique state, a force is applied to the transmission belt in a direction for returning the offset from the pulley body.

  Eventually, when the tilt angle is greater than 0 degree and less than 90 degrees, when the transmission belt is displaced, the pulley body causes a difference in height in the axial load direction in the pulley for the transmission belt. Both the return force caused by the inclination of the pulley and the return force caused by the pulley body being inclined with respect to the transmission belt act. Thus, the transmission belt travels at a position where the resultant force of the two return forces and the offset force acting on the transmission belt are balanced by the characteristics of the belt transmission device.

  Of the return force due to the inclination and the return force due to the crossing, the latter is more effective in preventing the deviation.

  Therefore, it is preferable that the tilt angle is more than 0 degree and less than 90 degrees. More preferably, in order to effectively use the return force due to the oblique crossing, the tilt angle is set to more than 0 degree and not more than 45 degrees. On the other hand, when the tilt angle is close to 0 degrees, it becomes difficult to generate a rotational moment about the above-mentioned pivot axis. Therefore, it is more preferable that the tilt angle is 5 degrees or more and 45 degrees or less, or 10 degrees or more and 30 degrees or less.

  The shaft member is cylindrical, and the support means includes a support rod inserted into the cylindrical shaft member, and the shaft member and the support rod between the cylindrical inner surface of the shaft member and the outer surface of the support rod. A pin that engages both sides to form the pivot, and the switching means holds the support rod so as to be rotatable about the rotation center axis, and the support rod is attached to the transmission belt. And a pivot mechanism that pivots a predetermined pivot angle so that the pivot is tilted at the tilt angle toward the front side in the belt traveling direction.

  According to this configuration, the pivot is configured by the pin that engages both the shaft member and the support rod between the cylindrical inner surface of the shaft member and the outer surface of the support rod. When the rod is rotated, the pin is rotated about the rotation center axis accordingly, and as a result, the tilt angle of the pivot is changed.

  Accordingly, the pivot mechanism rotates the support rod by a predetermined pivot angle in accordance with the traveling direction of the transmission belt, thereby changing the tilting direction of the pivot relative to the axial load direction. In other words, the pivot mechanism tilts the pivot at a predetermined tilt angle toward the front side in the belt traveling direction.

  The rotation mechanism is disposed on both sides of the pulley body, and when the transmission belt deviated from the pulley body comes into contact with the transmission member, the transmission member transmits the power of the transmission belt to the support rod as a rotational power, and the support rod And an engagement protrusion and an engagement recess that are provided on the holding member and that engage with each other when the support rod rotates by the predetermined rotation angle and restrict the support rod from rotating further. It is good also as a thing containing a groove | channel or an engagement concave groove and an engagement protrusion.

  When the transmission belt deviates from the pulley body and comes into contact with the transmission member, power (traveling force) of the transmission belt is applied to the transmission member, and rotational force is applied to the support rod through the transmission member. As a result, the support rod rotates around the rotation center axis, but the engagement protrusion and the engagement groove provided on the support rod and the holding member, or the engagement groove and the engagement protrusion engage with each other. The rotation is restricted when the rotation is performed by a predetermined rotation angle. The pivoting direction of the support rod is a direction in which the contact side with the transmission belt proceeds to the back side in the belt traveling direction, and the opposite side to the contact side proceeds to the front side in the belt traveling direction. It will tilt to the near side. Thus, the tilting direction of the pivot relative to the direction of the axial load is automatically switched to a desired direction in accordance with the switching of the traveling direction of the transmission belt.

  The belt transmission device of the present invention is a device in which the pulley as described above is pressed so as to apply tension to the transmission belt.

  Accordingly, meandering and shifting of the transmission belt can be prevented while applying a stable tension to the transmission belt, which is advantageous in sufficiently exhibiting the transmission capability of the transmission belt.

  The transmission belt may be of any type such as a flat belt or a toothed belt (timing belt). In the case of a flat belt, either the inner surface (transmission surface) or the outer surface (back surface) may be brought into contact with the pulley body, but in the case of a toothed belt, the outer surface (back surface) is preferably brought into contact with the pulley body.

  As described above, according to the present invention, the pulley body is supported by the shaft member so as to be rotatable around the rotation center axis, and the shaft member is rocked around the pivot axis orthogonal to the rotation center axis by the support means. Since the pivot is tilted to the near side of the belt running direction with respect to the axial load direction, the pulley body should be at least inclined when the transmission belt is offset on the pulley body. Therefore, it is possible to quickly and surely eliminate the shifting and meandering of the transmission belt with a simple structure.

  In addition, the switching means switches the tilting direction of the pivot relative to the direction of the axial load according to the switching of the traveling direction of the transmission belt, so that the transmission belt is offset or meandered in both forward and reverse rotations of the pulley. It can be quickly and reliably eliminated, and the range of use of the pulley is expanded.

  Further, the support means includes a support rod and a pin, the switching means includes a holding member and a rotation mechanism, and the rotation mechanism is disposed on both sides of the pulley body, the engagement protrusion, and the engagement recess. Since the groove includes the groove, when the transmission belt contacts the transmission member, the support rod rotates about a rotation center axis by a predetermined rotation angle, and the tilt direction of the pivot can be automatically switched. .

  In addition, according to the belt transmission device in which the transmission belt pulley is pressed so as to apply tension to the transmission belt, the transmission belt is applied with stable tension regardless of the traveling direction of the transmission belt. It is possible to prevent the transmission belt from meandering and shifting, which is advantageous in fully exhibiting the transmission capability of the transmission belt. This belt transmission device can be a device that switches the traveling direction of the transmission belt.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In the belt transmission device shown in FIG. 1, 1 is a drive pulley (flat pulley), 2 is a driven pulley (flat pulley), and a transmission belt (flat belt) 3 is wound around both pulleys 1 and 2, and this transmission A transmission belt pulley 4 is pressed against the back surface of the transmission belt 3 in order to apply tension to the belt 3.

  As shown in FIGS. 2 and 3, the pulley 4 is a cylindrical pulley body 5 around which the transmission belt 3 is wound, and a cylindrical body that rotatably supports the pulley body 5 around a rotation center axis C <b> 1 by a bearing 12. The shaft member 11, the support means 7 that supports the pulley body 5 and the shaft member 11 in a swingable manner, and the switching means 20 that switches the tilting direction of the pivot C2 described later in accordance with the switching of the traveling direction of the transmission belt. I have. The support means 7 includes a support rod 8 and a pin 9, and the switching means 20 includes a holding member 31 that holds the support rod 8 and a rotation mechanism that rotates the support rod 8. The rotation mechanism includes two transmission members 6, 6 disposed on both sides of the pulley body 5, an engagement protrusion 21, and an engagement groove 22.

  The support rod 8 includes a held portion 8a held by a holding member 31 such as a housing provided with the belt transmission device, and a cylindrical hole of the cylindrical shaft member 11 provided following one end of the held portion 8a. It consists of the support part 8b inserted. The held portion 8a is a rod having a circular cross section. On the other hand, the support portion 8b is formed by cutting a portion corresponding to the diameter direction of the cross-section circular rod into a D-shape, and by this D-cut, as shown in FIGS. The flat sliding surfaces 8c and 8c are formed.

  Accordingly, as shown in FIGS. 5 and 6, the support portion 8b includes flat sliding surfaces 8c and 8c corresponding to each other and arcuate surfaces on both sides connecting the side edges of the sliding surfaces 8c and 8c. Thus, the cross-sectional shape is substantially rectangular.

  On the other hand, the cylindrical hole of the shaft member 11 has a substantially rectangular cross section corresponding to the cross sectional shape of the support portion 8 b of the support rod 8. That is, on the inner surface of the shaft member 11, flat sliding surfaces 11a, 11a with which the sliding surfaces 8c, 8c of the support rod 8 are slidably contacted are opposed to each other. Arc surfaces on both sides connecting both side edges of 11a and 11a are formed.

  The pins 9 of the support means 7 are fitted into through holes formed in the support portion 8 b of the support rod 8, and both ends of the pins 9 are fitted into support holes formed in the shaft member 11. The pin 9 is disposed near the center of the width of the pulley body 5 and is orthogonal to the sliding surface 8 c of the support rod 8.

  Thus, the shaft member 11 is a pulley around the pivot C2 formed by the pin 9 between the arc surface on both sides of the support portion 8b of the support rod 8 and the arc surface on both sides of the cylindrical hole of the shaft member 11. Clearances 15 and 15 that allow the main body 5 to swing are formed.

  As shown in FIG. 3, one of the transmission members 6 is formed integrally with the shaft member 11 and projects from one end of the shaft member 11 in a flange shape in the centrifugal direction. The other transmission member 6 is coupled to the other end of the shaft member 11 and projects from the other end in a flange shape in the extending direction.

  Belt receiving portions 13 and 13 are formed in a cylindrical shape at the peripheral portions of the transmission members 6 and 6, and flanges 14 and 14 projecting in the centrifugal direction are formed on the outer edges of the belt receiving portions 13 and 13. The belt receiver 13 includes a belt contact surface 13 a that is flush with the belt winding surface of the pulley body 5. The belt contact surface 13 a is inclined so as to be higher in the centrifugal direction than the belt winding surface of the pulley body 5 as it is separated from the pulley body 5.

  As shown in FIGS. 3 and 4, the held portion 8a of the support rod 8 is inserted into a holding hole 32 having a circular cross section formed in the holding member 31, and is rotated around the rotation center axis C1 by bearings 33 and 33. It is held movable. The held portion 8a has an engaging protrusion 21 that is formed by a pin fitted on the outer peripheral surface and protrudes outward in the radial direction.

  On the inner peripheral surface of the holding hole 32, an engagement groove 22 that is recessed from the inner peripheral surface is formed at a position corresponding to the engagement protrusion 21, and the engagement groove 22 extends in the circumferential direction. It extends over a predetermined angular range. This angle range corresponds to a tilt angle α of the pivot C2 described later, and when the support rod 8 is rotated, the engagement protrusion 21 and the engagement groove 22 are engaged with each other, The rotation angle is restricted to an angle twice the tilt angle α with the axial load direction applied to the shaft member 11 as the center (see FIG. 4).

  As shown in FIG. 5, the transmission belt pulley 4 has the pin 9 (the pivot C <b> 2) in front of the belt traveling direction A with reference to the direction of the axial load (the load applied to the shaft member 11 due to the tension of the transmission belt 3) L. It is used by tilting it by a predetermined tilt angle α. At this time, in the held portion 8 a of the support rod 8, the engagement protrusion 21 and the engagement groove 22 are engaged, and the support rod 8 rotates in a direction to increase the tilt angle α. To be regulated. The tilt angle α is preferably set in an angle range that exceeds 0 degree and does not exceed 90 degrees. Further, the tilt angle α may be 90 degrees.

  In the usage mode shown in FIG. 5, as shown in FIG. 7, when the transmission belt 3 hung near the center of the width of the pulley main body 5 approaches the one side from the center of the pulley main body 5 as indicated by the chain line, The shaft 9 is shifted from the position of the pin 9 to one side of the pulley body 5 to act on the shaft member 11. As a result, a rotational moment about the pin 9 acts on the shaft member 11, and the shaft member 11 rotates and displaces around the pin 9 together with the pulley body 5.

  That is, as shown in FIG. 6, the support portion 8 b of the support rod 8, the pin 9 and the shaft member 11, when the axial load direction is parallel to the pin 9 (L0), the transmission belt 3 is connected to the pulley body 5. Even if it approaches the one side from the center of the pin, the rotational moment around the pin 9 does not occur. On the other hand, when the direction of the axial load is L that is inclined by an angle α with respect to the direction of the pin 9, when the transmission belt 3 approaches the one side from the center of the pulley body 5, the component force L1 causes the pin to A rotational moment around 9 is generated, and the shaft member 11 is rotationally displaced. The angle α corresponds to the tilt angle α of the pin 9 with respect to the direction of the axial load L.

  In the case of FIG. 5, the pulley body 5 is rotated and displaced around the pin 9 where the pulley body 5 is tilted by the axial load L, so that the pulley body 5 is connected to the transmission belt 3 as shown in FIG. 7 (plan view). As shown in FIG. 8 (indicated by arrow VIII in FIG. 3), the transmission belt 3 is in an oblique state with respect to the transmission belt 3 so that the side on which the side is offset becomes the front side in the belt traveling direction. Is inclined in the direction of the axial load L so that the side from which the deflection is offset is low and the opposite side is high. 5, 7 and 8, the state in which the pulley body 5 is rotationally displaced is indicated by a chain line.

  Accordingly, the transmission belt 3 is subjected to a return force (a force for returning the offset) due to the pulley body 5 being in an oblique state and a return force due to the inclination of the pulley body 5. This offset of 3 is prevented. That is, the transmission belt 3 travels at a position where the return force caused by the slanting and tilting of the pulley body 5 and the offset force acting on the transmission belt 3 due to the characteristics of the belt transmission device are balanced. Become. Even if the transmission belt 3 is largely displaced, the transmission belt 3 is returned to a position where the return force and the offset force are balanced.

  Further, the sliding surfaces 8c and 11a of the support rod 8 and the cylindrical shaft member 11 are brought into contact with each other by the axial load, and an appropriate sliding resistance acts between the sliding surfaces 8c and 11a. Therefore, when the transmission belt 3 is traveling near the center of the pulley body 5, the pulley body 5 can be prevented from slightly swinging due to traveling vibration of the transmission belt 3, and the transmission belt 3 is offset. When this occurs, the pulley main body 5 reacts with extreme sensitivity and is rotationally displaced, thereby preventing the pulley main body 5 from causing hunting that swings left and right in small increments.

  Then, it is assumed that the traveling direction of the transmission belt 3 is switched from the A direction shown in the upper diagram of FIG. 9 to the reverse B direction. At this time, it is assumed that the tilt direction of the pivot C2 is not changed, in other words, the pivot C2 is tilted to the back side in the belt traveling direction B with respect to the direction of the axial load L. In this state, when the transmission belt 3 moves from the center of the width of the pulley body 5 to one side thereof, a rotational moment around the pin 9 is generated and the shaft member 11 is rotationally displaced. Since the tilting direction of C2 is the back side of the belt traveling direction B, the pulley body 5 is opposite to the above-described side so that the side opposite to the side where the transmission belt 3 is offset is the front side in the belt traveling direction. The transmission belt 3 is inclined in the direction of the axial load L so that the side where the transmission belt 3 is offset is higher and the opposite side is lower. As a result, the transmission belt 3 is acted on by a force that promotes the displacement due to the pulley body being obliquely inclined and inclined. Thus, the transmission belt 3 deviates from the pulley body 5 and comes into contact with the belt receiving portion 13 of the transmission member 6 on one side.

  When the transmission belt 3 comes into contact with the belt receiving portion 13 of the transmission member 6, turning force around the rotation center axis C <b> 1 is applied to the transmission member 6. As a result, the support rod 8 advances in the belt traveling direction B on the side where the transmission belt 3 is wound around the pulley body 5 (lower side in FIG. 9), and on the opposite side (upper side in FIG. 9) in the B direction. Rotate to go in the opposite direction. That is, the support rod 8 rotates counterclockwise in FIG. 9 until the engagement protrusion 21 and the engagement groove 22 are engaged with each other. As a result, as shown in the lower diagram of FIG. 9, the pivot C2 tilts by a predetermined tilt angle α toward the front side of the belt traveling direction B with respect to the direction of the axial load L, and thereafter, the transmission belt 3 As described above, the vehicle travels at a position where the return force and the offset force are balanced.

  As described above, the transmission belt pulley 4 can quickly and surely eliminate the shifting and meandering of the transmission belt 3 regardless of the traveling direction of the transmission belt 3.

  Further, even if an abnormal external force that greatly deviates from the pulley main body 5 acts on the transmission belt 3, the transmission belt 3 hits the flange 14 of the transmission member 6 and is prevented from dropping from the transmission belt pulley 4. As described above, since the transmission belt 3 is prevented from running or meandering by the rotational displacement of the pulley body 5, the transmission belt 3 hardly contacts the flange 14, and the flange 14 can be omitted. It is.

  In addition, when the pulley 4 is used as a tension pulley as in the above embodiment, a stable tension can be applied to the transmission belt 3, which is advantageous in sufficiently exhibiting the transmission capability of the transmission belt 3.

  A loose crown may be attached to the outer peripheral surface of the pulley body 5. If the crown is gentle, it is possible to avoid applying a large load to the transmission belt 3.

  In the above embodiment, the belt receiving portion 13 of the transmission member 6 is formed in a cylindrical shape. However, the belt receiving portion 13 is formed in an arc shape only on the side where the transmission belt 3 is wound around the pulley body 5. Also good.

  When the belt receiving portion 13 is formed in a cylindrical shape as in the above embodiment, the transmission member 6 is provided so as to be rotatable with respect to the shaft member 11, and the transmission member 6 is brought into contact with the transmission member 6. If it is made to rotate, it will become advantageous in suppressing abrasion of the transmission belt 3 as much as possible. In that case, when the transmission belt 3 comes into contact with the transmission member 6, the transmission member 6 has a rotational resistance larger than that of the support rod 8 so that a part of the belt running force is converted into the rotational force of the support rod 8. .

  As a means for increasing the rotational resistance of the transmission member, for example, a power generation means that uses the rotation of the transmission member for power generation is provided to generate rotational resistance, a permanent magnet is attached to the transmission member to generate rotational resistance by magnetic force, For example, fins are attached to the transmission member, and the rotational force is converted into wind force to generate rotational resistance.

  Further, the rotation mechanism for rotating the support rod 8 by a predetermined rotation angle in accordance with the switching of the belt traveling direction is the mechanism of the above embodiment including the transmission member 6, the engagement protrusion 21, the engagement groove 22, and the like. It is not limited to. Further, the switching means for switching the tilt direction of the pivot C2 in accordance with the switching of the belt traveling direction is not limited to the mechanism for rotating the support rod 8 as in the above embodiment.

  Furthermore, in the above-described embodiment, the pulley 4 is used as a tension pulley. However, the pulley 4 may be used for other uses of the transmission device such as adjusting the length of the transmission belt, adjusting the contact angle, and changing the belt traveling direction.

  In addition, the pulley 4 can be used even when there is no change in the traveling direction of the transmission belt.

1 is a side view of a belt transmission device according to the present invention. It is a perspective view of the pulley which concerns on this invention. It is sectional drawing of the pulley. It is IV-IV sectional drawing of FIG. It is a front view which shows the use condition of the pulley. It is a figure explaining that a rotational moment generate | occur | produces in a shaft member by the shaft load in the same use state. It is a top view of the use state. FIG. 6 is a view taken along arrow VIII in FIG. 5. It is a figure explaining the change of the tilting direction of the pivot accompanying the change of the belt running direction.

Explanation of symbols

1 Drive Pulley 2 Driven Pulley 3 Drive Belt 4 Pulley 5 Pulley Body 6 Drive Member (Rotation Mechanism)
7 Support means 8 Support rod 8a Sliding surface (flat surface)
9 Pin 11 Shaft member 11a Sliding surface (flat surface)
20 switching means 21 engaging protrusion (rotating mechanism)
22 Engaging groove (turning mechanism)
31 Holding member

Claims (5)

A pulley body around which a transmission belt is wound;
A shaft member that rotatably supports the pulley body around a rotation center axis;
The shaft member, together with the pulley main body, is an axis orthogonal to the rotation center axis, and the direction in which the transmission belt contacts the pulley main body and travels on the basis of the direction of the axial load applied to the shaft member. Support means for swingably supporting around a pivot axis tilted at a predetermined tilt angle to the side,
A transmission belt pulley comprising: switching means for switching a tilting direction of the pivot relative to the direction of the axial load in accordance with switching of the traveling direction of the transmission belt. The pulley according to claim 1, wherein
The pulley for a transmission belt, wherein the tilt angle of the pivot is set in an angle range exceeding 0 degrees and not exceeding 90 degrees. In the pulley according to claim 1 or 2,
The shaft member is cylindrical,
The support means engages both the shaft member and the support rod between the support rod inserted into the cylindrical shaft member, and the cylindrical inner surface of the shaft member and the outer surface of the support rod. Comprising a pin, and
The switching means is
A holding member that holds the support rod so as to be rotatable about the rotation center axis;
A rotation mechanism that rotates the support rod by a predetermined rotation angle so that the pivot tilts at the tilt angle toward the front side of the belt traveling direction according to the traveling direction of the transmission belt. Including pulley for transmission belt. The pulley according to claim 3,
The rotation mechanism is
A transmission member disposed on both sides of the pulley body and transmitting the power of the transmission belt to the support rod as turning power when the transmission belt deviated from the pulley body comes into contact;
An engagement protrusion provided on the support rod and the holding member, and engaging with each other when the support rod is rotated by the predetermined rotation angle to restrict the support rod from rotating further; A pulley for a transmission belt including an engagement groove or an engagement groove and an engagement protrusion.   A belt transmission device in which the transmission belt pulley according to any one of claims 1 to 4 is pressed to apply tension to the transmission belt.

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