JPS5836915Y2 - Transmission band tensioning device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tensioning device for a power transmission band such as a cheno.

In general, in engines that transmit the rotation of the crankshaft to the camshaft that operates the valve mechanism through a chain drive mechanism, such as engines for driving motorcycles, the chain drive mechanism is designed to prevent the transmission chain from loosening. A tensioning device is installed to improve power transmission efficiency, reduce noise, and extend the life of the chain.However, the tensioning device for conventional chains of this type has to be adjusted manually, which is time-consuming. It took skill not only to swing it, but also to adjust it.

The object of the present invention is to provide a tensioning device for a transmission band with a simple structure, which can automatically and reliably perform the above-mentioned adjustment to ensure that the tension is exposed.

Hereinafter, an embodiment in which the tensioning device of the present invention is implemented in a motorcycle engine will be described with reference to the drawings.
A transmission chain 5 is suspended between driven sprockets 4 fixed to the camshaft 3.

On one side of the transmission chino 5, the case body 6 is provided with a tensioning device T of the transmission chino 5.

Next, the structure of this tensioning device T will be explained in detail.
A tensioner base 8 having a concave cross section is fixed to the case body 6 by several connecting bolts 7, and a guide path 9 is formed within the tensioner base 8.

This guide path 9 includes a long and thin sliding arm 1 having a U-shaped cross section.
0 is fitted to be slidable in the longitudinal direction (in the direction of the arrow in FIG. 1).

The sliding arm 10 is guided in its sliding motion by a guide roller 11 that is rotatably mounted on the middle part of the tensioner base 8 and by a tongue piece 12 cut and raised from the side wall of the tensioner base 8. It is designed not to deviate from Route 9.

A tensioner spring 13 is stretched between one end of the tensioner base 8 and the intermediate portion of the sliding arm 10, and the tensile force of the tensioner spring 13 acts to pull the sliding arm 10 to the right. .

On the right side of the tensioner base 8, the case body 6
The tensioner body 140 can be curved into an outwardly convex arc.
The base end is rotatably connected by a connecting pin 15, and the tip of this tensioner body 14 is connected to the sliding arm 1.
Pin connection 1 to a fork-shaped support 16 formed on the free end of 0
7 has been done.

The tensioner main body 14 is constructed by attaching an elastic suppressing member 19 made of rubber, synthetic resin, or the like to the outer surface of a band-shaped substrate 18 by baking or the like.

This elastic pressing member 19 is pressed against the outer surface of the power transmission chino 5.

A one-way locking mechanism is provided between the outer end of the tensioner base 8 and the outer end of the sliding arm 10, which allows the sliding arm 10 to move only in one direction, that is, to the right in FIG. .

The structure of this mechanism will be explained below. An insertion hole 20 is formed at the outer end of the tensioner base 8, and the insertion hole 20 has an inclined surface 21 that slopes outward and inward on the inner surface. In the hole 20, a key 23 connected by a pin 22 to the support portion 16 of the sliding arm 10 and a wedge piece 24 are fitted in an overlapping manner, and a wedge surface 25 formed on the wedge piece 24 is fitted to the inclined surface. 21.

Further, on the inner surfaces facing each other between the key 23 and the wedge piece 25,
A spring accommodating space 26 is formed, a compression spring 27 is accommodated in this spring accommodating space 26, and one end of this compression spring 27 is
It is engaged with a spring receiving surface 28 formed on the key 23, and the other end is engaged with a spring receiving surface 29 formed on the wedge piece 24, and the elastic force of this compression spring 27 causes the wedge piece 24 to It is biased in the wedge direction so as to protrude outward from the tensioner base 8.

Next, the operation of one embodiment of the present invention will be explained. As the sliding arm 10 has its hawk-shaped support portion 16 pulled to the right by the tensile force of the tensioner spring 13, the tensioner body 14 connected thereto is compressed by this traction force and is bent into an arched shape as shown in FIG.

Now, when the power transmission chain 5 is stretched and loosened, the tensioner spring 13
pulls the sliding arm 10 to the right by the amount of slack and further bends the tensioner body 14 until it applies a predetermined tension to the transmission chain 5, but at this time, the key 23 integrated with the sliding arm 10 is also pulled inside. While the wedge piece 2 moves in the direction (rightward in Figure 1)
4, the wedge surface 25 is the elastic force of the compression spring 27, and the inclined surface 2
Move outward (to the left in Figure 1) until it collides with 1.

Once the key 23 moves inward, the wedge action of the wedge piece 25 causes the sliding arm 10 to return to its original position, that is, the first position.
It does not return to the left direction in the figure.

When the power transmission chain 5 relaxes as described above, the tensioner main body 14 increases the degree of curvature outward in accordance with the relaxation, presses the power transmission chain 5 with a predetermined pressure, and always applies a predetermined tension. be able to.

Further, when it is necessary to loosen the tension of the tensioner, such as when disassembling the power transmission mechanism, the tensioner body 14 can be released from the locked state by pressing the wedge piece 25 inward.

Incidentally, in the above embodiment, a case has been described in which the power transmission chain 5 is used as the transmission band, but it goes without saying that other transmission bands such as a transmission belt can be used.

As described above, according to the present invention, when the transmission band of a power transmission chain or the like is loosened, the one-way locking mechanism is activated to automatically increase the degree of curvature of the tensioner body 14, and the tensioner body 14 is attached to the side of the transmission band. Since it can be in pressure contact with the transmission band, it is possible to always apply a constant tension to the transmission band, and not only does it not require any manual adjustment, but also can always apply a constant tension, improving power transmission efficiency. In particular, the one-way locking mechanism can be unlocked by simply pushing the wedge piece 24 from the outside inward, reducing noise and extending the life of the transmission band. Maintenance can be performed easily and easily.

Furthermore, the engaging surfaces of the inclined surface 21 and the wedge piece 24, which perform the locking function, can be set to have a wide area, and the locking operation can be ensured.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional side view of the device of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a sectional view taken along the line ■-■ of Fig. 1, and Fig. 4 is Fig. 1 IV.
-N line sectional view, and FIG. 5 is a sectional view taken along line V-V in FIG. L: One-way lock mechanism, 2: Drive sprocket as a driving wheel, 4: Driven sprocket as a driven wheel, 5: As a transmission band Transmission chaino, 6... Case body, 8...
...Tensioner base, 0...Sliding arm, 1
3... Tensioner spring, 4... Tensioner body, 20... Insertion hole, 1... Inclined surface, 23... Key, 24...Wedge piece,
7... Compression spring as a spring member.

Claims (1)

[Scope of utility model registration request] In a transmission band tensioning device that is pressed against a transmission band suspended between a driving wheel and a driven wheel and applies a predetermined tension to the transmission band, a tensioning device is fixed to the case body 6 on the side of the transmission band. a tensioner base 8; a sliding arm 10 slidably provided on the tensioner base 8; both ends connected to the case body 6 and the sliding arm 10, curved in an arch shape, and pressed against the transmission band. a tensioner body 14, which is stretched between the sliding arm 10 and the tensioner base 8, and a tensioner spring 13 for bending the tensioner body 14 toward the transmission band; a one-way locking mechanism for automatically sliding the sliding arm 10 only in a direction in which the tensioner body 14 increases its degree of curvature so as to follow the loosening of the transmission band; The locking mechanism includes an insertion hole 20 formed at one end of the tensioner base 8 and having an inwardly inclined surface 21 on the inner surface, and the sliding arm 10.
A key 2 connected to one end of the key 2 and inserted into the insertion hole 20
3, a wedge piece 24 inserted into the insertion hole 20 and sandwiched between the key 23 and the inwardly inclined surface 21, and this wedge piece 24.
1. A tensioning device for a power transmission band, characterized in that it comprises a spring member 27 that urges the traction band in the wedging direction.