JP2545718B2 - Tensioning device for belt drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension applying device for attaching to a belt driving device used in various industrial machines.

[0002]

2. Description of the Related Art The angular velocity and angular fluctuation characteristics between a drive shaft and a driven shaft of a belt drive device largely depend on the initial tension of the belt. In a relatively small device, the axial distance between the drive shaft and the driven shaft may fluctuate depending on the driving conditions. A generator is needed.

That is, for example, like a robot arm,
When a load is applied between the driving side and the driven side, the distance between the shafts may change.In such a case, if tension is applied to the belt by a tension pulley that is fixedly arranged, The tension changes as the distance changes. When controlling the drive on the driven side, this tension has a great influence on the control performance, so it is important to keep the tension constant.

[0004]

SUMMARY OF THE INVENTION The technical problem of the present invention is to provide a tension applying device which can keep the tension of the belt substantially constant even if the position of the drive shaft or the driven shaft of the belt drive device changes. It is in.

[0005]

Tension applying apparatus according to a first invention for solving the above problems SUMMARY OF THE INVENTION, the diameter of the drive pulley and the driven pulley are equal, and includes a tension pulley of diameter equal to those driving conditions In the belt drive device in which the axial distance between the drive shaft and the driven shaft fluctuates according to
Inside of a belt in which tension pulleys are respectively supported at connecting points of two connecting links having the drive shaft and the driven shaft as fulcrums, and these tension pulleys are wound between the drive pulley and the driven pulley. Contact with
It is characterized by giving tension to the belt.

The tension applying device according to the second aspect of the present invention is provided with a tension pulley in which the drive pulley and the driven pulley have the same diameter and a diameter equal to or smaller than that of the drive pulley and the driven pulley. In the belt drive device in which the inter-axis distance fluctuates, the tension pulleys are respectively supported at the connection points of the two connection links having the respective ends of the support links supporting the drive shaft and the driven shaft as fulcrums. The tension pulley is brought into contact with the outside of the belt wound between the driving pulley and the driven pulley to apply tension to the belt.

[0007]

[Operation] When the axial distance between the drive shaft and the driven shaft changes,
Correspondingly, the tension pulley is supported on the connecting link changes the position, but in particular, equal diameter of the drive pulley and the driven pulley, and when provided with a tension pulley equal diameter and their geometric analysis As is clear from the above, the tension acting on the belt can be made almost constant.

In the belt drive device, generally, the diameters of the drive pulley and the driven pulley are made different for acceleration and deceleration. In that case, an error depending on the diameter difference of the pulley and the inclination angle of the connecting link, etc. Will occur. However, when the diameter difference between the drive pulley and the driven pulley and the inclination angle of the connecting link are relatively small, the error is relatively small as compared with the case where the tension pulley is fixedly arranged, and there is no practical problem.

[0009]

1 and 2 show the construction of a first embodiment of a belt driving device equipped with a tension applying device according to the present invention. In the belt drive device of the first embodiment, the belt 5 is wound around the drive pulley 2 attached to the drive shaft 1 and the driven pulley 4 attached to the driven shaft 3. It is desirable that the drive pulley 2 and the driven pulley 4 have the same diameter, but they may have some differences, and in that case, considering various conditions to be described later, they are substantially equal within an allowable error range. Is set.

The belt drive device is premised on that the axial distance between the drive shaft 1 and the driven shaft 3 varies depending on the driving condition. For example, in the robot arm, the drive side and the driven side are driven. This is applied when the distance between the axes changes when a load or the like is applied between and.

As a mechanism for varying the inter-axis distance between the drive shaft 1 and the driven shaft 3, in the above belt drive device, the drive shaft 1 is provided with two connecting links 1 having the fulcrum as a fulcrum.
1 and 12 are rotatably connected, and two connecting links 21 and 22 having the fulcrum as the fulcrum are rotatably connected to the driven shaft 3, and a pair of connecting links 11 and 21 can be rotated at their tips. And the other pair of connecting links 12 and 22 are rotatably connected at their tips. And at each connecting point of those connecting links,
The tension pulleys 31 and 32 are rotatably supported, and these tension pulleys 31 and 32 are brought into contact with the inside of the belt 5 wound between the drive shaft 1 and the driven shaft 3 to obtain the belt 5. Is giving the tension of.

The diameters of the tension pulleys 31 and 32 are
It is desirable to set the diameters equal to the diameters of the drive pulley 2 and the driven pulley 4, but it is also possible to make some differences. To be done.

The belt drive device is premised on that the axial distance between the drive shaft 1 and the driven shaft 3 is changed.
In a stable state, the drive shaft 1 is supported by a bearing 6 provided in a fixed portion, and a bearing 7 supporting the driven shaft 3 is fixed to a support member 8 in order to keep the distance between the shafts in a predetermined state. The supporting member 8 is held by the fixed portion 10 via the spring 9.

In the belt drive device having the above structure, when the axial distance between the drive shaft 1 and the driven shaft 3 changes,
Correspondingly, the tension pulleys 31 and 32 supported by the pair of connecting links 11 and 21 and the other pair of connecting links 12 and 22 change their positions. In particular, the diameters of the drive pulley 2 and the driven pulley 4 are changed. equal, and if provided with a tension pulley 31, 32 of equal <br/> diameter as those, tension acting on the belt 5 becomes substantially constant.

This will be described with reference to FIG. 3. In FIG.

[Equation 1] Since the above relationship is geometrically established, it is possible to configure a belt drive system in which tension does not fluctuate even when the axial distance fluctuates. On the other hand, in FIG.

[Equation 2] As described above, tension fluctuations occur in the belt 5 depending on the axial distance. However, if the diameter difference between the driven pulley 4 and the tension pulley 31 is small, or if the axial distance fluctuation is small, the tension fluctuation is small. A belt drive system can be configured.

Further, in the belt driving device, generally, the diameters of the driving pulley 2 and the driven pulley 4 are made different for acceleration and deceleration, but in that case also, the difference in the diameter of the pulleys and the inclination angle of the connecting link, etc. An error will occur depending on However, when the diameter difference of the pulleys and the inclination angle of the connecting link are relatively small, the error is relatively small as compared with the case where the tension pulleys 31 and 32 are fixedly arranged, and there is no practical problem. .

In the second embodiment of the present invention shown in FIG. 4, tension pulleys 61 and 62 having the same function as in the first embodiment are wound between the drive pulley 2 and the driven pulley 4. The belt 5 is brought into contact with the outside of the belt 5. Also in the belt drive device of the second embodiment, it is desirable that the diameters of the drive pulley 2 and the driven pulley 4 are the same, but it is possible to make some difference within a range where an error can be allowed.

Also in the belt driving device of the second embodiment, the axial distance between the drive shaft 1 and the driven shaft 3 varies depending on the driving conditions. As a mechanism for this, the drive shaft 1 and the driven shaft are driven. The shaft 3 is supported by the support links 40 and 50, and the connecting links 4 having the fulcrums at both ends of the support link 40 are used.
1 and 42 are rotatably connected and a support link 50
To the both ends of the connecting links 51 and 52 rotatably therewith, the pair of connecting links 41 and 51 are rotatably connected at their tips, and the other pair of connecting links 42 and 52 is connected. They are rotatably connected at their tips. Then, the tension pulleys 61 and 62 are rotatably supported at the respective connection points of those connection links, and the tension pulleys 61 and 62 are
The belt 5 wound between the drive pulley 2 and the driven pulley 4 is brought into contact with the outside of the belt 5 to apply a required tension to the belt 5.

In the belt drive device having the above structure, when the axial distance between the drive shaft 1 and the driven shaft 3 changes,
Correspondingly, the tension pulley 61 and 62 changes its position. In particular, the diameter of the drive pulley 2 and the driven pulley 4 is equal, and when provided with a or the diameter of the tension pulley 61, 62 equal those, belt The tension acting on 5 becomes almost constant.

That is, the belt tension fluctuation when the axial distance between the drive shaft 1 and the driven shaft 3 fluctuates is geometrically determined in the same manner as described in the first embodiment with reference to FIG. When the tension pulleys 61 and 62 are brought into contact with the outside of the belt as in the second embodiment,
The belt tension slightly increases as the axial distance decreases. Therefore, in order to cancel it, it is preferable to form the tension pulleys 61 and 62 in advance to have a diameter substantially equal to or slightly smaller than that of the drive pulley 2 and the driven pulley 4.

The error caused by the difference in diameter between the driving pulley 2 and the driven pulley 4 is the same as that described in the first embodiment. Further, in FIG. 1, the link 11 or link 21 and the link 12 or link 22
In FIG. 4, link 41 or link 51 and link 4
The tension can be made variable by inserting a length adjusting device such as a turnbuckle into the 2 or the link 52.

In a general belt driving device, as long as a certain tension is applied to the belt, even if the belt is slightly fluctuated, it does not hinder the power transmission, but it is controlled to repeatedly apply a torque. Alternatively, when the angle is precisely controlled, the fluctuation of tension becomes a problem. The belt drive device described above can be effectively used in such a case.

[0023]

According to the belt drive device of the present invention described in detail above, the tension of the belt is kept substantially constant even if the position of the drive shaft or the driven shaft is changed, and the tension that enables precise drive is thereby obtained. An application device can be obtained.

[Brief description of drawings]

FIG. 1 is a front view of a belt driving device including a tension applying device according to a first embodiment of the present invention.

FIG. 2 is a plan view of the first embodiment.

FIGS. 3A and 3B are explanatory diagrams for explaining belt tension fluctuations.

FIG. 4 is a front view of a belt driving device having a tension applying device according to a second embodiment of the present invention.

[Explanation of symbols]

 1 drive shaft, 2 drive pulley, 3 driven shaft, 4 driven pulley, 5 belt, 6,7 bearing, 11,12 connection link, 21,22 connection link, 31,32 tension pulley, 40,50 support link, 41, 42 connection link, 51,52 connection link, 61,62 tension pulley.

Claims (2)

(57) [Claims] 1. A equal diameter of the drive pulley and the driven pulley, and provided with a tension pulley of diameter equal to those in a belt drive system center distance varies between the drive shaft and the driven shaft in response to driving conditions, Inside of a belt in which tension pulleys are respectively supported at connecting points of two connecting links having the drive shaft and the driven shaft as fulcrums, and these tension pulleys are wound between the drive pulley and the driven pulley. Contact with
A tension applying device in a belt driving device, wherein a tension is applied to the belt. 2. A belt drive device in which a drive pulley and a driven pulley have equal diameters, and a tension pulley having a diameter equal to or smaller than that of the driven pulley is provided, and an axial distance between the drive shaft and the driven shaft varies depending on driving conditions. , Tension pulleys are respectively supported at the connection points of the two connection links having the respective ends of the support link supporting the drive shaft and the driven shaft as fulcrums, and these tension pulleys are connected to the drive pulley and the driven pulley. A tension applying device in a belt driving device, wherein the belt is wound around the belt and is brought into contact with the outside of the belt to apply tension to the belt.