JPS6317887Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to a chain tensioner that is applied when a chain transmission system is used to transmit power from a drive shaft to a driven shaft.

[Conventional technology]

In this type of chain transmission system, a driving sprocket and a driven sprocket mesh with the chain, and these are attached to a driving shaft and a driven shaft, respectively, and maintain a constant distance between the shafts.
Therefore, if the chain stretches, it will no longer mesh with the sprocket, causing problems such as tooth skipping and noise. Therefore, a method is generally adopted in which a constant tension is applied to the chain to eliminate meshing play with the sprocket and absorb the elongation, as in, for example, Japanese Utility Model Application Publication No. 70643/1983. For this purpose, a tensioner with an idler sprocket is sometimes used, which uses spring force to tension the chain.
In this state, fix the tensioner lever.

[Problem that the invention attempts to solve]

However, the method of tensioning the chain using an idler sprocket requires a certain amount of space around the chain transmission system, and is therefore difficult to use in situations where such conditions cannot be met. The present invention was developed based on the above circumstances, and provides a chain tensioner that allows the driven sprocket to operate as a tensioner without using an idler sprocket, thereby enabling tension to be applied even under severe installation conditions. The purpose is to

[Means to solve the problem]

For this purpose, the chain tensioner of the present invention has a shaft formed at one end of at least one driven sprocket that meshes with the chain, and a shaft hole formed at the other end, and the diameter of the shaft hole is set to at least the diameter of the chain. The diameter of the driven shaft inserted into the shaft hole is made larger by an amount equivalent to an adjustment allowance for adjusting the elongation, and an engaging portion is formed in the driven sprocket in a radial direction from the center of the shaft hole of the driven sprocket. The driven shaft is provided with a connecting piece projecting in the radial direction, the connecting piece is engaged with the engaging portion, and the shaft formed on one end side of the driven sprocket is pivotally supported by a tension arm. is configured to do so.

【Example】

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. In the figure, reference numeral 1 denotes a drive sprocket, which is attached to a drive shaft (crankshaft) 2. Driven sprockets 3 and 4 are mounted on both sides of the drive sprocket 1.
is installed. Further, power is transmitted to the driven sprockets 3 and 4 from the driving sprocket 1 via a chain 5 wound between them. One of the driven sprockets 3 is
Although it is fixed to the driven shaft 6 as usual, the shaft formed at one end side of the other driven sprocket 4 is attached to the tip of a tension arm 8 which is pivoted at a fulcrum 7 via a bearing 9. It is pivoted. The other end of the driven sprocket 4 on the side opposite to the tension arm 8 is provided with a shaft hole 11 through which the driven shaft 10 is inserted. The outer diameter of the driven shaft 10 is set to be larger than the outer diameter of the driven shaft 10 by an amount equivalent to an adjustment allowance. As an engagement means for engaging the driven sprocket 4 and the driven shaft 10, a sliding groove 12 as an engagement portion is formed on the driven sprocket 4 side in a radial direction from the center of the shaft hole 11. On the other hand, the driven shaft 10 is provided with a link 13 that protrudes in the radial direction, and the head of the link 13 is slidably disposed in the sliding groove 12, and the head of the link 13 is slidably disposed within the sliding groove 12. Rotation is caused by the driven shaft 10 via the connector 13.
transmitted to. The tension arm 8 is elastically supported by a tension coil spring 14 on the side where the chain 5 is tensioned, and a bolt 15 for adjusting and fixing is inserted into an elongated hole 16 along a predetermined radius of curvature centered on the fulcrum 7. It is inserted so that it can be tightened to the frame side (not shown). In addition, the reference numeral 17 in the figure is a chain guide located inside the drive space of the chain 5, and the frame is fixed. In such a configuration, the driven shaft 10 is rotatably fixed to the frame side, and the inner diameter of the shaft hole 11 of the driven sprocket 4 is larger than the outer diameter of the driven shaft 10, so that the tension coil spring 14
The driven sprocket 4 is moved to the side where the chain 5 is tensioned via the tension arm 8 by the urging force of
The tension of the chain 5 depends on the movement of the driven sprocket 4,
That is, this is achieved by moving the tension arm 8. In this case, the rotation center of the driven sprocket 4 and the center of the driven shaft 10 are eccentric for adjustment, but the rotational driving force is applied to the shaft hole 1 of the driven sprocket 4.
The transmission is transmitted from the driven sprocket 4 to the driven shaft 10 by the engagement between the sliding groove 12 formed in the driven sprocket 1 and the connector 13 of the driven shaft 10. A predetermined tension (in this case, determined by the strength of the tension spring 14) is applied to the chain 5.
In this state, tighten the bolt 15 to stop the tension arm 8 from swinging. As a result, the chain 5 is properly tensioned. If chain 5 is stretched, bolt 15 should be replaced again.
Just loosen it and readjust it. In the embodiment shown in FIG. 4, the link 13 is in the form of a sliding key, and may be configured to be able to slide within the sliding groove 18 provided on the driven shaft 10. In addition, the sliding groove 12 or the sliding groove 18
Of course, a liner may be added to the material to improve wear resistance.

[Effect of the idea]

As described in detail above, the present invention connects the driven shaft and the driven sprocket with a linking element so that rotational power can be transmitted even if both are eccentric to each other. The tension adjustment for the chain can be easily achieved in a relatively small space without requiring an idler sprocket, and excellent practical effects can be obtained in that it can be applied to places with severe spatial conditions.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing an embodiment of the present invention;
FIG. 2 is a longitudinal sectional side view of the main part, FIG. 3 is a front view of the main part, and FIG. 4 is a front view of the main part of another embodiment. 1... Drive sprocket, 2... Drive shaft,
3, 4... Driven sprocket, 5... Chain, 6
... Driven shaft, 7 ... Fulcrum, 8 ... Tension arm, 9 ... Bearing, 10 ... Driven shaft, 11 ...
...Shaft hole, 12...Sliding groove, 13...Connector, 1
4...Tension coil spring, 15...Bolt,
16... Long hole, 17... Chain guide, 18...
Sliding groove.

Claims (1)

[Claims for Utility Model Registration] A shaft is formed at one end of at least one driven sprocket that meshes with the chain, and a shaft hole is formed at the other end, and the diameter of the shaft hole is adjusted to adjust at least the elongation of the chain. the diameter of the driven shaft to be inserted into the shaft hole is larger by an equivalent amount than the diameter of the driven shaft inserted into the shaft hole, and an engaging portion is formed in the driven sprocket in a radial direction from the center of the shaft hole of the driven sprocket; A connecting piece is provided that projects in the radial direction, and the connecting piece is engaged with the engaging portion, and the shaft formed on one end side of the driven sprocket is pivotally supported on a tension arm. Chain tensioner.