JP2008095921A - Idler pulley device for flat belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase durability without enlarging an idler pulley device for flat belt. <P>SOLUTION: In a structure of an idler pulley device P for a flat belt, a pulley shaft 10 supporting a pulley main body 8 is composed of an annular outer shaft 2 and an inner shaft 1 fixed on the outer shaft 2 not to move around an axis thereof, the pulley main body 8 is provided on an outer circumference of the outer shaft 2 relatively rotatably around the shaft, the outer shaft 2 is supported by the inner shaft 1 rotatably around an axial center C2 crossing an axial center C1 of the inner shaft 1, and a convex spherical surface 1a formed on an outer diameter surface of the inner shaft 1 and a concave spherical surface 2a formed on an inner diameter surface of the outer shaft always slide during the rotation. The outer shaft 2 and the inner shaft 1 adhere under a condition where both of the convex and the concave spherical surface 1a, 2a can slide at any rotation position, and load acting on the pulley shaft 10 from the flat belt B via the pulley main body 8. Consequently, assembly can be facilitated by simplifying a support structure while increasing stiffness of the device and improving durability. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an idler pulley device for a flat belt.

In general, in a flat belt transmission device in which a driving force is transmitted from one pulley to the other pulley by a flat belt stretched between two pulleys, the flat belt snakes during travel, or the pulley On the other hand, the flat belt may run biased to either side in the width direction.
If the flat belt is meandering or biased, the widthwise end of the flat belt may come into contact with the pulley flange or the like, which may cause damage to the side surface of the flat belt.

  Therefore, in order to prevent this meandering and bias, a flat belt idler pulley device having a centering function is used.

As an idler pulley device for a flat belt having an alignment function, for example, a technique called a “crown” in which the outer peripheral surface of a pulley is formed in a spherical shape centered on the rotation center of the pulley is generally used. .
If a pulley provided with a “crown” is employed, when the flat belt is biased to either side of the pulley, the restoring force for moving the flat belt to the central portion having a relatively large pulley diameter is Since it acts on the flat belt, the flat belt can be returned to the normal position by its restoring force.

  As another flat belt idler pulley device having a centering function, the pulley is rotatably supported in the traveling direction of the flat belt by a rotating shaft, and the pulley is a rotating shaft orthogonal to the rotating shaft. When the flat belt is biased and a tension difference is generated between one end and the other end in the width direction, the pulley moves around the rotation axis and moves in the traveling direction. Some devices are designed to be tilted with respect to.

When the pulley is inclined, the flat belt is in a state of being inclined such that the side on which the flat belt is biased is the front side in the traveling direction with respect to the rotating shaft at the sliding portion with the pulley. That is, the flat belt inclines so that the side where the flat belt is biased has a relatively small diameter and the opposite side has a large diameter at the sliding portion with the pulley.
Due to this inclination, the same restoring force as in the case where the “crown” is provided is applied to the flat belt to try to return the flat belt to the normal position. A rotational moment works and the inclination of a pulley is eliminated (for example, refer to patent documents 1 and 2).
JP 2005-299847 A JP-A-2005-121205

When the pulley provided with the “crown” is employed, the flat belt has a problem that stress is concentrated in the central portion in the width direction. In order to extend the life of the flat belt, it is desirable that no stress concentration occurs in a part of the belt.
Further, since the idler pulley device for a flat belt described in Patent Document 1 or 2 supports most of the load acting on the pulley from the flat belt with the rotating shaft, the rotating shaft must be strong. I must. Thus, if the durability of the rotating shaft is increased, there is a problem that the apparatus becomes large.
Further, the flat belt idler pulley device has a complicated structure in order to firmly support the rotating shaft, and there is a problem that it takes time to assemble.

  Accordingly, an object of the present invention is to improve the durability of an idler pulley device for a flat belt having a centering function without increasing the size of the device.

  In order to solve the above problems, the present invention provides a flat belt idler comprising a pulley body having a contact surface with a flat belt on the outer periphery and a pulley shaft that supports the pulley body so as to be relatively rotatable about the axis. In the pulley apparatus, the pulley shaft includes an annular outer shaft and an inner shaft that is fitted to an inner diameter portion of the outer shaft and fixed to each other so as not to move around the shaft. The outer shaft is supported so as to be rotatable about an axis that intersects the axis of the inner shaft with respect to the inner shaft, and when the outer shaft rotates, The outer shaft and the inner shaft employ a configuration in which a convex spherical surface formed on the outer diameter surface of the inner shaft and a concave spherical surface formed on the inner diameter surface of the outer shaft always slide.

  According to this configuration, the outer shaft and the inner shaft are in close contact with each other so that the concavo-convex spherical surfaces can slide at any rotational position of the outer shaft. For this reason, the load acting on the pulley shaft from the flat belt through the pulley body is transmitted between the spherical surfaces in close contact between the outer shaft and the inner shaft. If a load is transmitted between the contact surfaces, the rigidity of the entire pulley device including the pulley shaft is increased, and rattling between members can be eliminated. Therefore, the support accuracy of the pulley and the durability of the member can be improved.

In addition, if a load is transmitted between the contact surfaces as described above, a large load does not act on the rotating shaft. For this reason, it is not necessary to enlarge the support member of an outer shaft and an inner shaft, and the number of parts can be reduced and the support structure can be simplified. Therefore, the assembly of the pulley device can be simplified.
In addition, as a configuration for supporting the outer shaft so as to be able to rotate around the axis intersecting the axis of the inner shaft with respect to the inner shaft, a combination of a groove and a projection that guides the rotation of the outer shaft with respect to the inner shaft. Alternatively, a well-known means such as a combination of a pin and a hole for rotatably supporting both of them can be adopted. Further, for example, in a configuration in which the outer shaft and the inner shaft are arranged coaxially, when the rotation direction of the outer shaft with respect to the inner shaft is orthogonal to the axis of the inner shaft, the outer shaft and the inner shaft A rotating shaft such as a pin that connects both of them so as to pass through both the axes and to be orthogonal to the axis of the inner shaft may be adopted.

  In the above configuration, if the center of the convex spherical surface of the inner shaft and the concave spherical surface of the outer shaft are matched, both spherical surfaces of the outer shaft and the inner shaft are always in surface contact with each other. It becomes high and is preferable.

  The present invention relates to an idler pulley device for a flat belt having a centering function, and a convex spherical surface formed on the outer diameter surface of the inner shaft and a concave shape formed on the inner diameter surface of the outer shaft when the outer shaft rotates. Since the configuration in which the spherical surface slides constantly is adopted, the durability can be enhanced without increasing the size of the apparatus.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an idler pulley device P for a flat belt in which a pulley body 8 and a pulley shaft 10 are incorporated via a ball bearing so as to be rotatable around the shaft. The flat belt idler pulley apparatus P is, as shown in FIG. 6, the flat belt B passed sieved between two pulleys P _1, P _2, from one of the driving pulley P ₁ to the other of the driven pulley P ₂ In the flat belt transmission to which the driving force is transmitted, it is arranged in the middle between the _two pulleys P ₁ and P ₂ .

The configuration of the apparatus includes a pulley main body 8 having a contact surface with the flat belt B on the outer periphery, and a pulley shaft 10 that supports the pulley main body 8 so as to be relatively rotatable about an axis.
The pulley shaft 10 includes an annular outer shaft 2 and an inner shaft 1 fitted to the inner diameter portion of the outer shaft 2, and an insertion hole 14 provided coaxially with the axis C 1 of the inner shaft 1. A fixed shaft (not shown) can be fixed inside.

  A bearing inner ring 6 constituting a bearing portion is press-fitted to the outer periphery of the outer shaft 2, and the bearing inner ring 6 is fixed to the outer shaft 2 so as not to move around the axis. Further, a circumferential groove having a circular arc cross section for guiding the plurality of steel balls (rolling elements) 3 so as to roll is formed on the entire outer periphery of the bearing inner ring 6. Further, a circumferential groove having a circular arc shape is formed on the entire inner circumference of the pulley body 8 so as to face the circumferential groove of the bearing inner ring 6.

A large number of steel balls 3, 3... Are accommodated between the circumferential groove of the bearing inner ring 6 and the circumferential groove of the pulley body 8, and the bearing inner ring 6 and the bearing are interposed via the steel balls 3, 3. A pulley body 8 as an outer ring is supported so as to be rotatable about an axis.
Each of the steel balls 3, 3... Is held by a ring-shaped cage 4 so as to maintain a predetermined interval in the circumferential direction, and in the space between the bearing inner ring 6 and the pulley body 8. A seal 5 that seals the space in which grease is sealed is assembled outward in the axial direction.

Further, the outer shaft 2 and the inner shaft 1 can always slide between a convex spherical surface 1 a formed on the outer diameter surface of the inner shaft 1 and a concave spherical surface 2 a formed on the inner diameter surface of the outer shaft 2. It is inserted in the state. Reference numeral 15 in the drawing is a notch for inserting the inner shaft 1.
The inner shaft 1 has an outer shape in which both ends of a sphere whose cross section in any direction is a perfect circle are cut in parallel, and the concave spherical surface 2 a of the outer shaft 2 is a convex shape of the inner shaft 1. The spherical surface 1a is in spherical contact with the entire surface. That is, the convex spherical surface 1a of the inner shaft 1 and the concave spherical surface 2a of the outer shaft 2 are spherical surfaces having the same center over the entire circumference.

The outer shaft 2 is rotatably supported around the axis C2 by pins 13 and 13 having an axis C2 orthogonal to the axis C1 of the inner shaft 1 with respect to the inner shaft 1. The outer shaft 2 and the inner shaft 1 are fixed by a pin 13 so as not to move around the axis C1. As shown in FIG. 2, the pin 13 is press-fitted into the pin holes 11 and 11 formed in the inner shaft 1 through the pin holes 12 and 12 formed in the outer shaft 2.
The pin 13 is press-fitted and fixed to the pin hole 12 of the outer shaft 2 and is inserted into the pin hole 11 of the inner shaft 1 (insertion in a state where it can be easily inserted and removed). The outer diameter of the pin 13 may be set.

  Further, the concave spherical surface 2 a of the outer shaft 2 and the convex spherical surface 1 a of the inner shaft 1, or any of them may be subjected to a treatment such as coating for reducing frictional resistance during sliding.

  The operation of the flat belt idler pulley device P will be described. The contact surface 8a of the pulley body 8 is applied to the flat belt B traveling in the direction of arrow A shown in FIG. At this time, the axial center C2 of the pin 13 as the rotation shaft is set so as to form an acute angle with the flat belt B on the side approaching the pulley body 8 as shown in the figure.

When the flat belt B is biased to either side in the width direction of the flat belt B with respect to the contact surface 8a of the pulley main body 8, as shown in FIG. 5, the pulley main body 8 is moved around the axis C2. A force is applied to the flat belt B so as to return its position to the center in the width direction of the contact surface 8a. Since this “force to return” increases as the inclination of the pulley body 8 increases, the biased flat belt B eventually returns to the center in the width direction with respect to the pulley body 8. Go. The point a in the figure indicates the start point of the contact portion between the flat belt B and the contact surface 8a, and the point b indicates the end point of the contact portion.
The same applies to the case where the flat belt B is biased in the direction opposite to the direction shown in FIG. 5, and a force is applied to the flat belt B to return its position to the center in the width direction of the contact surface 8a. Therefore, the flat belt B does not come off from the pulley body 8.

When the outer shaft 2 is rotated, the outer shaft 2 and the inner shaft 1 are slid between the concave and convex spherical surfaces 2a and 1a at any rotational position of the outer shaft 2, and both the concave and convex portions are always moved. The spherical surfaces 2a and 1a are kept in close contact with each other. For this reason, the load acting on the pulley shaft 10 from the flat belt B through the pulley body 8 is always transmitted between the contact surfaces 1 a and 2 a between the outer shaft 2 and the inner shaft 1.
For this reason, the rigidity of the idler pulley device P for the flat belt is increased, and rattling between members can be eliminated. Therefore, the support accuracy of the pulley body 8 and the durability of the member can be improved.

  Moreover, if a load is transmitted between the contact surfaces of the concave and convex spherical surfaces 2a and 1a as described above, a large load does not act on the pins 13 and 13 that are the pivot shafts. For this reason, it is not necessary to enlarge the support member of the outer shaft 2 and the inner shaft 1, and the number of parts can be reduced and the support structure can be simplified. Therefore, the assembly of the flat belt idler pulley device P is simple.

In this embodiment, a ball bearing is employed to rotatably support the pulley body 8 on the pulley shaft 10, but other bearing structures may be employed.
Further, the present invention is not limited to the embodiment in which the axis C1 of the inner shaft 1 and the axis C2 of the pin 13 are orthogonal to each other, and the directions of both axes C1 and C2 are actually set at angles other than a right angle. The present invention can be implemented even in a mode in which the planes intersect with each other so as to intersect with each other, or in a mode in which the directions of both axial centers C1 and C2 are three-dimensionally intersected and arranged in a so-called “twisted position relationship”. It is.

1 shows an embodiment, (a) is a plan view, (b) is a side sectional view Exploded view of the main part of FIG. Action diagram showing the rotation of the outer and inner shafts Action diagram showing contact with flat belt Arrow view from arrow X direction of FIG. Overall view of flat belt drive

Explanation of symbols

1 Inner shaft 2 Outer shaft 3 Steel ball (rolling element)
4 Cage 5 Seal 6 Bearing inner ring 8 Pulley body 8a Abutting surface 10 Pulley shaft 11, 12 Pin hole 13 Pin (rotating shaft)
14 Insertion hole 15 Notch B Flat belt C1, C2 Shaft center P Flat belt idler pulley device

Claims (2)

In an idler pulley apparatus for a flat belt comprising a pulley body 8 having a contact surface 8a for contact with the flat belt B on the outer periphery, and a pulley shaft 10 that supports the pulley body 8 so as to be relatively rotatable around the axis.
The pulley shaft 10 is composed of an annular outer shaft 2 and an inner shaft 1 that is fitted to an inner diameter portion of the outer shaft 2 and fixed to each other so as not to move around the shaft. The main body 8 is relatively rotatable, and the outer shaft 2 is supported so as to be rotatable around an axis C2 intersecting the axis C1 of the inner shaft 1 with respect to the inner shaft 1. The outer shaft 2 and the inner shaft 1 always have a convex spherical surface 1 a formed on the outer diameter surface of the inner shaft 1 and a concave spherical surface 2 a formed on the inner diameter surface of the outer shaft 2. An idler pulley device for a flat belt characterized by sliding.   2. The idler pulley device for a flat belt according to claim 1, wherein the center of the convex spherical surface 1a of the inner shaft 1 is coincident with the center of the concave spherical surface 2a of the outer shaft 2.

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