JP2006292051A - Pulley for transmission belt and belt drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulley for a transmission belt for preventing the transmission belt 3 from undulating. <P>SOLUTION: A cylindrical pulley body 5 is rotatably supported by a tubular shaft member 7, in which a supporting rod 8 is inserted and they are jointed by a pin 9 so as to be swingable. The pin 9 is tilted forwardly in the direction of rotation of the pulley 5 with respect to the direction of the axial-load. Thus, if the transmission belt 3 is driven aside, the pulley 5 is tilted in the direction of the axial load L to generate undulation, and is rotatably displaced aslant with respect to the transmission belt 3 so as to generate restoring force in the transmission belt 3. When the axis (axis C2) of the pin 9 is set aside from the rotation center-axis C1 of the puley body 5 in the direction of the axial load L, the rotation moment generated around the axis C2 is effectively increased by positional deviation of the axial load L, when the transmission belt 3 is driven aside. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In general, in a transmission device using a flat belt, the belt may meander while the vehicle travels, or may travel slightly toward the one side of the pulley. This is because the flat belt is more sensitive to changes in equipment components than other belts, such as deviation from the normal position of the pulley shaft, pulley shaft deflection due to changes in shaft load, and pulley swing. . When such meandering / offset running occurs, the flat belt comes into contact with the flange of the flat pulley, causing fluffing of 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 pulleys 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.

  In addition, when the pulley crown is formed in a spherical shape with the rotation center of the pulley as the center, even if the effect of preventing the belt from shifting is enhanced, the problem is that 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, when a guide pulley or the like is arranged on both sides of the flat belt to restrict its running position, both sides of the flat belt always come into contact with such restriction members. 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.

  In the present invention, when the transmission belt is displaced, the pulley is displaced by utilizing the fact that the position of the axial load applied to the pulley and the pulley shaft is changed by the tension of the belt. Prevented meandering and sideways running.

That is, the present invention includes a cylindrical pulley body around which a transmission belt is wound, and a support mechanism that rotatably supports the pulley body and swings around a predetermined pivot axis. A pulley for a transmission belt,
The pivot shaft tilts at a predetermined tilt angle forward of the rotation direction of the pulley body with respect to the axial load direction when viewed along the rotation center axis of the pulley body, and the axial load from the rotation center of the pulley body. It is characterized by being offset in the direction of.

  According to the transmission belt pulley configured as described above, when the belt is displaced on the pulley body and the axial load is shifted from the position of the pivot in the width direction of the pulley body, the pivot load causes the pivot body to move to the pivot body. A rotation moment centering on the axis acts to cause rotational displacement (swing) around this pivot axis. As a result, the pulley body is inclined so that the side where the belt is offset moves in the direction of the axial load, that is, when the level in the direction of the axial load is high, the side where the belt is offset is low and the opposite side is high. . That is, since the outer peripheral surface of the pulley body is inclined in the same manner as the crown, a return force in a direction opposite to the above-described offset direction acts on the belt.

  Further, the pivot that becomes the center of the rotational displacement as described above is tilted forward in the rotational direction of the pulley body with respect to the axial load direction (that is, the tilt angle is more than 0 degree and less than 90 degrees). Therefore, the rotational displacement of the pulley body includes not only the component in the axial load direction but also the front-rear direction (the direction in which the belt is running while contacting the pulley body) perpendicular to the axial load direction. Ingredients included. That is, the pulley body not only inclines in the direction of the axial load as described above, but the side on which the belt is offset moves to the front side in the belt traveling direction, and comes into contact with the belt in an oblique manner, This also gives the belt a force in the direction of returning the offset from the pulley body.

  That is, when the axial load deviates from the position of the pivot shaft in the width direction of the pulley body due to the deviation of the transmission belt, the pulley body is rotated around the pivot shaft by the rotational moment generated thereby, and the axial load is reduced. Inclined so that the direction is high and low, and oblique to the belt. Both the return force due to the inclination and the return force due to the oblique action act on the transmission belt, and the resultant force of both return forces and the offset force acting on the belt due to the characteristics of the belt transmission device Thus, the belt travels at a position where the belts are balanced, thereby preventing the belt from meandering and shifting.

  As described above, the return force due to the inclination acting on the pulley body of the pulley for the transmission belt and the return force due to the skew are more effective in preventing the deviation, so the return force due to the skew is preferably effective. Therefore, the tilt angle of the pivot is preferably set in the range of more than 0 degree and not more than 45 degrees, and more preferably not more than 30 degrees.

  However, when the tilt angle of the pivot is reduced, the axial load component acting in the direction of the pivot is increased, and the frictional resistance of the sliding portion receiving the axial load component in the pivot direction is increased in the support mechanism. Since the surrounding axial load component becomes relatively small, the rotational moment due to this becomes small, and thus the sliding friction resistance becomes large, and when the rotational moment becomes small, the rotation of the pulley body may be delayed. May not rotate smoothly.

  On the other hand, in the above configuration, the rotational moment is increased by offsetting the pivot from the rotation center of the pulley body in the direction of the axial load. That is, when the pulley body is pivotally displaced around the pivot as described above, the position where the axial load acts geometrically away from the pivot in the pulley width direction due to this displacement, the rotational moment naturally increases. However, if the position of the pivot is offset as described above, the amount of displacement in the pulley width direction of the axial load position accompanying the rotational displacement of the pulley body increases, thereby increasing the rotational moment increasing effect. It can be done.

  In this way, the rotational moment around the pivot acting on the pulley body can be effectively increased due to the shift of the axial load position. Therefore, in the present invention, even if the tilt angle of the pivot is small, the rotational displacement of the pulley body is reduced. Even if the sliding frictional resistance is large, the pulley body can be smoothly rotated and displaced without delay with respect to the transmission belt, and the necessary and sufficient return force can be applied. Travel can be eliminated quickly.

  In the transmission belt pulley configured as described above, preferably, the support mechanism includes a cylindrical shaft member that rotatably supports the pulley body, a support rod inserted into a cylindrical hole of the shaft member, and the support. And engaging means for oscillatingly engaging the rod and the shaft member around the pivot shaft (invention of claim 2). If it carries out like this, the support mechanism of a pulley main body can be made into the compact thing settled in the inner peripheral side.

  In such a case, as an engaging means for swingably engaging the support rod and the shaft member, it is preferable that, for example, a pin is inserted into a through hole formed in the support rod, and both ends thereof are respectively connected to the shaft. It is to fit into a support hole that opens on the cylinder inner surface of the member (invention of claim 3).

  Furthermore, a preferable configuration of the pulley for the transmission belt is formed on the inner surface of the cylinder of the shaft member and the outer peripheral surface of the support rod so that opposing surfaces facing each other in the direction of the pivot are orthogonal to the pivot, A rolling bearing is interposed between the two opposing surfaces (invention of claim 4).

  In this way, since the axial load component applied to the support rod from the shaft member is received by the rolling bearing, the sliding frictional resistance generated by this axial load component can be minimized, and when the axial load is large or the pivot shaft Even when the tilt angle is small, it is possible to further reduce the resistance against the rotational displacement of the pulley body and further enhance the action of the above-described invention.

  According to another aspect, the present invention is a belt transmission device in which the transmission belt pulley as described above is pressed so as to apply tension to the belt.

  In this belt transmission device, while applying a stable tension to the belt by the above-described transmission belt pulley, the belt meandering and shifting can be quickly eliminated by swinging the pulley body. It is advantageous to fully demonstrate the transmission capability of the belt.

  The belt according to the present invention may be of any kind, such as a flat belt or a toothed belt (timing belt). In the case of a flat belt, either the inner peripheral surface or the outer peripheral surface may be brought into contact with the pulley body. In the case of a toothed belt, the rear surface of the transmission surface is brought into contact with the pulley body.

  As described above, according to the present invention, the pulley body around which the belt is wound is rotatably supported, and is supported so as to be swingable around the pivot shaft tilted in a predetermined direction with respect to the axial load direction. Therefore, when the belt is shifted in the width direction on the pulley body, the pulley body is inclined so as to produce a height difference in the axial load direction, and the pulley body is inclined with respect to the belt. Thus, it is possible to apply a return force for returning the offset to the belt, thereby preventing the belt from meandering and shifting with a simple structure without deteriorating the durability of the belt.

  Moreover, by offsetting the pivot from the rotation center of the pulley body in the direction of the axial load, it is possible to effectively increase the rotational moment around the pivot caused by the displacement of the axial load position. The pulley body can be smoothly rotated and displaced without delay with respect to the offset, and a return force without excess or deficiency can be applied to the belt. In this way, the meandering and offset running of the belt can be eliminated quickly and reliably.

Further, in the belt transmission device, wherein the transmission belt pulley is pressed so as to apply tension to the belt, the belt meandering and the piece as described above while applying a stable tension to the belt. It is possible to quickly and surely eliminate the slippage traveling, and this is advantageous in fully exhibiting the transmission capability of the belt.

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

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

  The overall configuration of the belt transmission device A shown in the drawing is merely an example, and various layouts may be adopted as necessary when the belt transmission device A is used for automobiles, agricultural machines, various industrial machines, and other devices. it can.

-Structure of pulley for transmission belt-
2 and 3, each of the transmission belt pulley 4 includes a cylindrical pulley body 5 around which the transmission belt 3 is wound, and the pulley body 5 around a rotation center axis C1 by bearings 6 and 6. And a support mechanism that swingably supports around a preset pivot axis C2. The support mechanism includes a cylindrical shaft member 7 fitted on the inner periphery of the inner ring of the bearings 6 and 6, a support rod 8 inserted into a cylindrical hole of the shaft member 7, and a pin constituting the pivot C2. Nine.

  The support rod 8 has a flange formed near the center in the longitudinal direction, and a portion 8a (hereinafter referred to as a base end side) closer to one end side than the flange is a support such as a housing of the belt transmission device A. It can be attached. On the other hand, on the distal end side 8b of the support rod 8 inserted into the cylindrical hole of the shaft member 7, flat surfaces 8c and 8d (hereinafter referred to as D cut) whose outer periphery is cut so that the rod 8 has a D-shaped cross section. Are formed at two locations corresponding to each other in the diametrical direction.

  The two D-cut surfaces 8c and 8d are substantially parallel to each other and are substantially orthogonal to the pivot C2. In addition, both ends of the through hole having a circular cross section formed in the support rod 8 along the pivot C2 are opened to the two D cut surfaces 8c and 8d, respectively. The pin 9 is inserted so as to protrude from the D-cut surfaces 8c and 8d. Further, one of the D-cut surfaces 8c becomes a load receiving surface that receives an axial load L (see FIG. 4) via a bearing 10 as will be described later.

  Thus, the cylindrical inner surface of the shaft member 7 is substantially flat so as to face the outer side in the radial direction of the one D-cut surface 8c serving as a load receiving surface and to be substantially parallel to the D-cut surface 8c. An opposing surface 7a is formed. A support hole having a circular cross section is formed on each of the opposing surface 7a and the arcuate cylindrical inner surface facing the other D-cut surface 8d, and both end portions of the pin 9 are respectively formed in the support holes. By being inserted, the shaft member 7 and the support rod 8 are pivotably engaged around the pivot C2.

  Furthermore, in this embodiment, as a characteristic part of the present invention, the axial center of the pin 9, that is, the pivot C2, does not intersect with the rotation center axis C1 of the pulley body 5, as shown in FIG. In addition, the position of the support rod 8 is displaced in the radial direction from the rotation center axis C2. These two axes C1 and C2 are in a positional relationship orthogonal to each other in a plan view shown in FIG. 3, in other words, the pivot C2 moves in parallel with the radial direction of the support rod 8 on the axis perpendicular to the rotation center axis C1 ( Offset).

  Further, between the one D-cut surface 8c of the support rod 8 and the opposed surface 7a of the shaft member 7, both of them can smoothly rotate relative to each other while receiving the load between the both surfaces 7a and 8c. In this manner, a ball bearing 10 (others may be a rolling bearing such as a needle bearing) is interposed. On the other hand, a bowl-shaped resin sliding material 11 is disposed between the other D-cut surface 8 d and the arc surface of the shaft member 7, and the outer peripheral surface of the pin 9 and the inner surface of the through hole of the support rod 8. Between the two, a cylindrical resin sliding material 12 is disposed.

  Thus, the pulley body 5 is rotatably supported around the rotation center axis C1 by the bearings 6 and 6 with respect to the shaft member 7, and the pin 9 (with respect to the support rod 8 together with the shaft member 7). It is pivotably supported around a pivot C2). In addition, between the circular arc surface of the rod outer periphery connected to the D-cut surfaces 8c and 8d of the support rod 8 and the cylindrical inner surface of the shaft member 7 surrounding the rod member, the shaft member 7 is connected to the pulley body 5 with the pin 9 as an axis. At the same time, gaps 13 and 13 are formed to allow the rocking.

-Changes in belt travel position due to pulley swinging-
In the use state as shown in FIG. 1, the transmission belt pulley 4 configured as described above has one D-cut surface 8 c serving as a load receiving surface in the support rod 8 as schematically shown in FIG. 4. Positioned on the pulley body 5 on the side where the belt 3 is wound (the lower side in the figure), the shaft load L applied from the shaft member 7 is received by the ball bearing 10. Thus, by receiving the axial load L by the ball bearing 10, the sliding friction resistance with respect to the relative rotation of the pulley body 5 and the shaft member 7 can be minimized while stably receiving the axial load L.

  The transmission belt pulley 4 is also a characteristic part of the present invention. As shown in the drawing, the pivot C2 is set on the front side in the rotational direction of the pulley body 5 with respect to the direction of the axial load L, that is, in the drawing. It is used by being tilted by a predetermined angle α to the front side in the belt traveling direction indicated by an arrow R. In this way, when the belt 3 running around the pulley body 5 is shifted in the width direction, a rotational moment is generated due to the displacement of the axial load position, and the pulley body 5 is moved in the direction of the axial load L. In addition to being inclined, the belt 3 is inclined with respect to the belt 3, and a return force for returning the deviation of the belt is effectively generated.

  Specifically, as shown in FIG. 5, when the transmission belt 3 is hooked around the center of the width of the pulley body 5, the vector L of the axial load (shown by a solid line) intersects the pivot C2, and the component force L0 is While acting in parallel with the pivot C2, the component force L1 acts at right angles to the pivot C2. The component force L1 acts so as to twist the pin 9, but no rotational moment is generated around the pin 9 (the pivot axis C2).

  On the other hand, although not shown in the figure, when the transmission belt 3 moves from the center of the pulley body 5 to one side thereof, the axial load L acts on the one side, so that the component L1 of the axial load L acts around the pivot C2. As a result, a rotational moment acts on the shaft member 7. That is, if the direction of the axial load L is parallel to the pivot C2, L = L0 and L1 = 0 at this time, and no rotational moment is generated around the pivot C2, but the axial load L is not as in this embodiment. If the direction is inclined from the pivot C2, a rotational moment around the pivot C2 is generated by the component L1 of the axial load. Here, the angle α corresponds to the tilt angle of the pivot C2 with respect to the direction of the axial load L.

  In this embodiment, as shown in FIG. 4 and the like, the pivot C2 is tilted forward in the rotational direction of the pulley body 5, so that the pulley body 5 and the shaft member 7 rotate around the pivot C2 as described above. Then, the pulley body 5 is offset in the direction of the axial load L as shown in an exaggerated manner in FIG. The transmission belt 3 is offset as shown in an exaggerated manner in FIG. 7 (viewed in the direction of arrow VII in FIG. 4) as viewed in the direction of the axial load L at the same time that the opposite side is inclined to be higher and the opposite side is higher. The transmission belt 3 is obliquely crossed so that the incoming side is the front side in the belt traveling direction. Note that, in FIGS. 4, 6, and 7, a state in which the pulley body 5 is rotationally displaced is indicated by a virtual line (two-dot chain line).

  Due to the rotational displacement of the pulley body 5, the transmission belt 3 is caused to return to the transmission belt 3 by a slanting state (force to return the offset) and the pulley body 5 is inclined. The return force works, thereby correcting the traveling position of the transmission belt 3. That is, the transmission belt 3 is acted on by the return force resulting from the inclination and skewing of the pulley body 5 and the offset force acting on the transmission belt 3 due to the characteristics of the belt transmission device A, and both balance. It will run in the position. The transmission belt 3 is returned to a position where the return force and the offset force are balanced even if the transmission belt 3 is largely displaced due to disturbance.

  Here, since the return force due to the crossing has a higher effect of returning the position of the belt 3 than the return force due to the inclination, in order to effectively use the return force due to the crossing, the tilt of the pivot C2 is inclined. The angle α is preferably set in the range of more than 0 degree and 45 degrees or less, and more preferably 30 degrees or less. In this embodiment, as shown in FIG. 4 as an example, the tilt angle α is set to about 10 to 20 °.

  However, as the tilt angle α of the pin 9 decreases, the axial load L acts geometrically in the direction of the axial center of the pin 9 (the direction of the pivot C2), so the component force L0 in the direction of the pivot C2 increases. Thus, the frictional resistance of the sliding portion in the support mechanism is increased, while the component force L1 (the axial load component acting around the pivot C2) acting on the pulley body 5 and the shaft member 7 is reduced. There is a possibility that the rotational displacement of the main body 5 may be delayed or not smoothly rotated.

  In this regard, in this embodiment, a ball bearing is provided between one D-cut surface 8c of the support rod 8 and the opposing surface 7a of the shaft member 7 so as to receive the component force L0 of the axial load L in the direction of the pivot C2. 10 is arranged to minimize sliding frictional resistance, and the pivot C2 is offset from the center of rotation of the pulley body 5, thereby effectively increasing the rotational moment acting on the pulley body 5. .

  That is, when the transmission belt 3 is offset on the pulley body 5, as described above, a rotational moment is generated due to the shift of the axial load L, and the pulley body 5 is rotationally displaced around the pin 9 (the pivot axis C2). However, when viewed in the direction of the pivot axis C2 as shown in FIGS. 6 and 7, the axial load L is geometrically caused by the rotational displacement of the pulley body 5 as shown in phantom in FIG. Will be separated from the pivot C2 in the pulley width direction. Thus, if the distance between the load application point P and the pivot C2 increases, the rotational moment increases.

  And when the case where the pivot C2 is offset and the case where the pivot C2 is not offset (when the pivot C2 intersects the rotation center axis C1) are compared, if the rotation angle of the pulley body 5 is the same, When the offset is present (indicated by the phantom line in the figure), the axial load acting point P accompanying the rotational displacement of the pulley body 5 in the pulley width direction is compared to the case without the offset (indicated by the broken line in the figure). Displacement increases. That is, the rotational moment acting on the pulley body 5 can be increased more effectively by offsetting the pivot C2 as in this embodiment.

  In FIG. 8, the offset amount of the pivot C2 (pin 9) is shown larger than the actual amount in order to illustrate that the displacement of the axial load application point P increases due to the offset of the pivot C2 (pin 9). The rotation angle of the pulley body 5 is also exaggerated.

  Thus, the rotational moment around the pivot C2 acting on the pulley body 5 due to the deviation of the axial load L can be effectively increased, and the axial load component L0 in the pivot C2 direction can be stably received by the ball bearing 10. However, since the sliding frictional resistance can be minimized, in the transmission belt pulley 4 of this embodiment, the pulley body 5 is smoothly rotated and displaced with respect to the side of the transmission belt 3 without delay, and a necessary and sufficient return force is obtained. Thus, the meandering and offset running of the belt can be prevented promptly and reliably.

  In addition, in this embodiment, not only the ball bearing 10 is disposed on the one D-cut surface 8c serving as the receiving surface of the axial load L in the support rod 8, but also the D-cut surface 8d on the opposite side and the outer periphery of the pin 9 The sliding members 11 and 12 are respectively disposed between them to reduce the sliding frictional resistance as much as possible. This is also advantageous in smoothly rotating and disengaging the pulley body 5.

  Therefore, according to the transmission belt pulley 4 according to this embodiment, when the transmission belt 3 that is wound around the pulley body 5 and travels in the width direction, the pulley body 5 can be smoothly moved without delay due to a shift in the axial load. As a result, a necessary and sufficient return force is immediately applied to the belt 3, and the traveling position is quickly corrected toward the center in the width direction.

  Thus, in the belt transmission device A of this embodiment, the transmission belt pulley 4 provided with the function of returning the displacement of the transmission belt 3 as described above is used as a tensioner. While the applied tension is applied, the transmission belt 3 can be prevented from meandering and running away from the belt, and the transmission capability of the belt can be sufficiently exhibited.

-Other embodiments-
In the above-described embodiment, in the support mechanism of the transmission belt pulley 4, the ball bearing 10 is disposed between the one D-cut surface 8 c of the support rod 8 and the opposing surface 7 a of the shaft member 7 facing the D-cut surface 8 c. However, this is not always necessary, and instead of the ball bearing 10, for example, a resin sliding material or the like may be provided in the same manner as the D cut surface 8d on the opposite side.

  Further, in the transmission belt pulley 4, the pivot C2 is constituted by the pin 9 inserted through the through hole formed in the support rod 8. However, the present invention is not limited to this, but the pivot C2 is not shown. For example, it can be configured by a hemispherical convex portion formed on the D-cut surface 8c of the support rod 8, or can be configured by fitting a sphere into a recess formed in the D-cut surface 8c. In these cases, a recess for fitting the hemispherical convex portion or the sphere is provided on the facing surface 7 a of the shaft member 7.

  Alternatively, as shown in FIG. 9 and FIG. 10, the pivot C <b> 2 is configured by a hook-shaped convex portion 72 a provided on the inner peripheral surface of the shaft member 70, and the outer periphery of the distal end side 80 b of the support rod 80 is It is also possible to provide a groove portion 80c having a semicircular cross section for slidably holding the hook-shaped convex portion 72a so as to engage both (engagement means). With this configuration, the offset amount of the pivot C2 can be maximized in a limited space on the pulley inner peripheral side.

  In the example shown in both the drawings, the shaft member 70 is composed of a shaft member main body 71 on the outer peripheral side and an intermediate member 72 having a U-shaped cross section made of a resin sliding material fitted on the inner peripheral side. The intermediate member 72 is provided with a hook-shaped convex portion 72a. Further, the support rod 80 is provided with a distal end side 80b having a rectangular cross section so as to bend and extend from a flat plate-like flange portion 80a on the proximal end side, and the groove portion 80c is opened on one of the outer peripheral surfaces thereof. is doing.

  Then, the intermediate member 72 is fitted from the outside to the distal end side 80b of the support rod 80 so that the hook-shaped convex portion 72a is accommodated in the groove portion 80c of the support rod 80, and then the intermediate member 72 is inserted. The shaft member main body 71 divided into two halves is assembled from the outside in the radial direction, and these are integrally fitted into the inner race of the bearing 60 from the inside. In this assembled state, a gap 13 is formed between the outer peripheral surface of the support rod distal end side 80b and the inner peripheral surface of the shaft member 70, and the flange-shaped convex portion 72a and the groove portion 80c slide to surround the peripheral surface. The shaft member 70 is rotated about the pivot C <b> 2 with respect to the support rod 80 by being rotationally displaced in the direction.

  Accordingly, the pulley body 50 fitted from the outside to the outer race of the bearing 60 is rotatable around the rotation center axis C1 and swings around the pivot C2 together with the shaft member 70. It has become. According to such a structure, there is an advantage that the number of parts is smaller than that of the above-described embodiment, and the cost can be reduced.

  Further, in the support mechanism for the transmission belt pulley 4, the engaging means for engaging the shaft members 7 and 70 and the support rods 8 and 80 are not necessarily provided between them. The mechanism may have any structure as long as the mechanism can be rotatably supported and can be swingably supported around the pivot C2.

  Furthermore, in the above-described embodiment, the transmission belt pulley 4 of the present invention is used as a tensioner. However, the use of the transmission belt pulley of the present invention is not limited thereto. For example, the length of the belt and the contact angle can be adjusted. It can be used for various applications in belt transmission devices such as adjustment and change of belt running direction.

  As described above, the transmission belt pulley and the belt transmission device according to the present invention reliably ensure meandering and deviation without reducing the durability and transmission capacity of the flat belt or increasing the manufacturing cost. This makes it possible to fully utilize flat belts with extremely high transmission efficiency. For example, they can be applied to automobiles, agricultural machinery, various industrial machines, household appliances, and other devices to achieve a high energy-saving effect. It is extremely highly available.

1 is a side view of a belt transmission device according to the present invention. It is the partial sectional view which looked at the pulley for power transmission belts concerning the present invention in the direction of a pivot. It is the partial cross section figure which looked at the pulley for power transmission belts which concerns on this invention in the direction orthogonal to a pivot. It is a side 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. FIG. 5 is an explanatory diagram schematically showing a rotational displacement state of the pulley body when the belt is offset in the same use state as seen in a direction orthogonal to the axial load L (direction of arrow VI in FIG. 4). It is explanatory drawing which shows typically the rotational displacement state of a pulley main body when a belt in the same use state sees in the direction of the axial load L (direction of arrow VII of FIG. 4). It is explanatory drawing which shows the displacement of the action point of the axial load accompanying the rotation displacement of a pulley main body by contrasting the case where a pivot is offset and the case where it is not offset. FIG. 3 is a view corresponding to FIG. 2 according to another embodiment in which a pivot is configured by a hook-shaped convex portion provided on an inner peripheral surface of a shaft member. FIG. 4 is a view corresponding to FIG. 3 according to another embodiment.

Explanation of symbols

A Belt drive 1 Drive pulley 2 Driven pulley 3 Flat belt 4 Drive belt pulley 5 Pulley body 6 Bearing 7 Shaft member 7a Opposing surface 8 Support rod 8c D cut surface 8d D cut surface 9 Pin 10 Ball bearing (rolling bearing)
50 pulley body 60 bearing 70 shaft member 72a hook-shaped convex part (engagement means)
80 Support rod 80c Groove (engagement means)
C1 Rotation center axis C2 Axis L Axis load

Claims (5)

A cylindrical pulley body around which a transmission belt is wound;
A support mechanism for rotatably supporting the pulley body and swinging around a predetermined pivot axis;
The pivot shaft tilts at a predetermined tilt angle forward of the rotation direction of the pulley body with respect to the axial load direction when viewed along the rotation center axis of the pulley body, and the axial load from the rotation center of the pulley body. Transmission belt pulley characterized by being offset in the direction of. The transmission belt pulley according to claim 1,
The support mechanism is
A cylindrical shaft member that rotatably supports the pulley body;
A support rod inserted into the cylindrical hole of the shaft member;
An engagement means for engaging the support rod and the shaft member so as to be swingable around the pivot shaft. The transmission belt pulley according to claim 2,
The transmission belt pulley, wherein the engagement means is a pin inserted into a support hole that is inserted into a through hole formed in the support rod and has both end portions opened on the inner surface of the cylinder of the shaft member. . In the pulley for transmission belts in any one of Claim 2 or 3,
Opposing surfaces that face each other in the direction of the pivot are formed on the cylindrical inner surface of the shaft member and the outer peripheral surface of the support rod, respectively, and a rolling bearing is interposed between the opposing surfaces. A pulley for a transmission belt. 5. A belt transmission device, wherein the transmission belt pulley according to claim 1 is pressed so as to apply tension to the transmission belt.

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