JPS587157Y2 - Two-axis balancer chain tensioner - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of the Cheno tensioner in a two-axis balancer.

More specifically, a leaf spring member is disposed between two pivotally connected members forming the chain tensioner, and an eccentric cam is provided at the free end of the leaf spring member so as to be biased to rotate in one direction. The present invention relates to a chain tensioner for a two-axis balancer that is capable of reliably tensioning the chain with a simple and compact structure.

As shown in Fig. 1, the two-shaft balancer connects a pair of balancer sprockets 1 and 2 with a chain 3, and curves the upper middle part of the chain 3 downward to engage the sprocket 4 of the crankshaft. Then, the crankshaft sprocket 4 drives the cheno 3, rotates the balancer sprockets 1 and 2, and rotates the balancer sprocket 1.
, 2 (not shown) is rotated to achieve balance.

In the above two-shaft balancer, a chain tensioner 5 is provided in a space inside the chain 3 between the balancer sprockets 1 and 2.

The chain tensioner 5 consists of a fixed guide part 6 and a movable member 7 pivotally connected to the guide part 6 with a pin 8, and flexible members 6a, 7a made of rubber or the like are pasted on the surface facing each chain. The guide part 6 guides the chino so that it does not become disengaged.

Therefore, a coil spring is inserted between the above members 6 and 7,
A system in which the movable member 7 follows the slack of the chain has been proposed, but with this, the spring load decreases as the chain stretches, making it difficult to maintain sufficient tension. This is not optimal as the load increases.

The inventor of the present invention has devised the present invention in view of the above-mentioned problems of the Cheno tensioner and to effectively solve the problems.

The object of the present invention is to provide a plate spring member with one end fixed to the other member between the members of the Cheno tensioner, and an eccentric cam attached to the free end of the plate spring member to rotate in one direction. Provided is a cheno tensioner for a two-axis balancer equipped with.

Therefore, the purpose of the present invention is to use a plate spring member to press and tension the cheno, to prevent it from sagging or loosening, and to prevent the cheno from loosening or elongating beyond the specified limit so that it can be moved in a manner that requires tensioning. When the resistance of the member decreases, the rotation of the cam is allowed and the movable member is spread out, and the tensioning action of the plate spring is performed, so that the ceno can be elastically tensioned with a constant force at all times, and the above can be done in a simple and compact manner. To provide a cheno tensioner that can be designed with a flexible structure.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows an enlarged longitudinal sectional view of the cheno tensioner according to the present invention, and FIG. 3 shows a perspective view showing the state in which the cam is attached.

Reference numeral 10 denotes a fixed guide member, the main body 11 of which is formed of a steel plate material in the shape of a downwardly open channel, and a sliding rubber 12 is attached to the surface of this by baking or the like.

Reference numeral 14 denotes a movable member, the main body 15 of which is molded from the same material as above in the shape of an upwardly opened channel, and a sliding rubber 16 is adhered to the lower surface.

The movable member 140 main body 15 is fitted between the fixed guide member 100 main body side plate 11a, and the raised wall 15a formed at the rear of the main body 15 and the rear side plate 11a of the main body 11 are connected by the pin 13.
The movable member 14 is pivotably attached to the fixed guide member 10 with the pin 13 as a fulcrum.

One end of the leaf spring member 17 is fixed to one end of the main body 15 of the movable member 140, that is, on the side of the pivot joint 13, and the other end of the leaf spring member 17 extends to the front between the members 10 and 14 and has a free end. do.

This free end 17a is formed into a bifurcated shape as seen in FIG. 3, forming a bearing portion 18.18 wound in a loop shape on the left and right, and an entry portion 19 is formed between the bearing portions 18.18.

A cam 20 is interposed between the entry portions 19, and eccentric shafts 21 protruding from both sides of the cam 200 are fitted into bearing portions ia, ia to rotatably lock the cam 20.

The cam profile 20a on the surface of the cam 200 is constructed by continuously providing a plurality of flat surfaces 20b...
...A corner portion 20c is provided between each.

A stopper portion 20d is provided on a part of the surface of the cam 200, and one end side 22a of the torsion spring 22 is locked to this,
The winding part 22b of the spring 22 is wound around the eccentric shaft 21, and the other end 22b is wound around the eccentric shaft 21.
2c is locked to the leaf spring 17 side.

In this way, a round kicking force is applied to the cam 20 in the clockwise direction in FIG.

In the above, as shown in FIG. 2, the free end 17a of the leaf spring 17 comes into contact with the lower surface of the main body 11 of the fixed guide member 100 via the cam 20, and the movable member 14 is moved by the pin 13 in the figure as a reaction.
It is pressed counterclockwise using the fulcrum, and the lower part 3 of Cheno 3
Suppress a, correct sagging of cheno, and make it tense.

When the chain loosens and stretches, the contact pressing force between the contact surface 20b of the cam 200 and the main body 11 of the fixed guide member 100 decreases, and the cam 20 is prevented from rotating in the direction of the larger stroke due to the bias of the spring 22. , the pressure decreases on the contact surface 2
When the main body 11 rotates beyond the corner 20c between 0b and 20c, the main body 11 comes into contact with the next profile surface with a larger stroke.

As a result, the stroke change plate spring 17 is pushed down,
The movable member 14 connected to this is pushed down, and the leaf spring 17
The lower side 3a of the ceno 3 is compressed by zero action, and the elongation of the ceno is followed and absorbed.

In this way, the cam 20 automatically rotates to increase the stroke in accordance with the elongation of the chino, absorbing the elongation of the chino and applying pressure to it.

Furthermore, once extended, the chino may try to return to its original position due to fluctuations in the rotation of the internal combustion engine or the like.

In this case, a force in the return direction acts on the movable member 14 via the sliding rubber 16, and this force causes the leaf spring member 17 to bend, causing the movable member 14 to move clockwise with the pin 13 as a fulcrum in FIG. It rotates and absorbs the return of the tension on the cheno, preventing it from becoming too tensioned.

In this way, the extended length of the cheno is compensated for by the stroke of the cam, and the excessive tension of the cheno is compensated for by the leaf spring 1.
Since it is absorbed by the deflection of 7, a uniform tension elastic force can always be obtained.

Although the illustrated example has been described above, it is preferable that the cam 20 has a polygonal shape as shown in the figure, so that moderation can be maintained.

As is clear from the above, according to the present invention, the leaf spring member presses the chain to prevent it from loosening or sagging, and if the chain extends or loosens beyond a specified value, the cam rotates to increase the stroke. The movable member expands to follow the extension of the cheno, tensions the cheno, corrects the stroke with a cam, and uses the leaf spring to absorb excessive tension on the cheno, so the pressure of the leaf spring is always uniform. It can be tensioned by force and can obtain an effective cheno tensioner of the two-axis balancer.

The above is a fixed guide member that is simple in structure, compact, and narrow, consisting of a leaf spring and a rotationally biased cam.
It can be easily set between movable members.

[Brief explanation of the drawing]

Figure 1 shows an example of a conventional Cheno tensioner, Figure 2 shows an example of a conventional Cheno tensioner.
The figure is a longitudinal cross-sectional view of the chain tensioner according to the present invention.
The figure is a perspective view showing how the cam is attached. In the drawing, 10 is a fixed guide member, 14 is a movable member, and 17 is a fixed guide member.
2 is a leaf spring member, and 20 is a cam.

Claims (1)

[Scope of utility model registration request] In a two-shaft balancer equipped with a chain tensioner consisting of a fixed guide member between a chain stretched between balancer sprockets and a movable member pivotally connected to the chain, one end is provided between the movable member and the fixed guide member. A two-axis balancer characterized in that a leaf spring member is fixed to a movable member, and an eccentric cam is provided at the free end of the leaf spring member in contact with the fixed member and elastically biased to rotate in one direction. Cheno tensioner.