JP3234537U - Chain tensioner mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chain tensioner mechanism for reducing an impact load received on a starting chain when starting an engine and stably operating the engine.
SOLUTION: A chain tensioner mechanism 6 is fixed to a cell motor side sprocket 3 and a crank side sprocket 4 of an engine body 1, a chain 5 wound around a cell motor side sprocket 3 and a crank side sprocket 4, and an engine body 1 side. Bracket 9, a slider 8 that guides the chain 5, a guide arm 10 that is attached to the bracket 9 and supports the slider 8 and swings with the slider 8, and a stopper that suppresses the swing of the guide arm 10 toward the bracket 9. It has a bolt 13.
[Selection diagram] Fig. 1

Description

The present invention relates to a chain tensioner mechanism for motorcycles and the like.

When starting an engine of a motorcycle or the like, a chain for starting the engine is wound around the transmission between the starter motor side and the crank shaft side. The rotation of the starter motor causes the crank shaft to rotate via the chain to start the engine. Normally, since a one-way clutch is provided in the transmission path of the starter motor, the structure is such that the rotational force of the crank shaft is not transmitted to the starter motor when the engine is started.

Conventionally, a chain tensioner is attached by an automatic adjustment mechanism that prevents the slider from reversing when a force is applied in the direction in which the chain is stretched when the starter motor rotates when the engine is started. The chain is constantly pressed by the elastic force of the torsion spring attached to the arm of the tensioner, reducing the fluttering of the chain, and even if the chain stretches or the slider wears due to aging, the spring elastic force. The one-way function that prevents the arm from returning and prevents the chain from loosening.

When the engine is running, the chain tensioner is attached to the loose side of the chain, but when the crank is rotated by the rotational force of the starter motor when the engine is started, it is on the tension side, so there are the following problems.

(1) Rotate the crank by the starter motor When the engine is started, the compression explosion process is repeated, the crank rotates momentarily faster than the rotation of the starter motor, or the chain is stretched due to sudden changes in rotation such as the engine running idle. The chain is repeatedly loosened, and at this time, an impact load acts on the chain.

(2) In (1), if the chain flutters due to a sudden change in rotation, the one-way effect that prevents reversion does not work, and the slider and arm are flipped more than necessary on the mounting bracket side and rotate at high speed adjacent to each other. There is a risk of interfering with the existing clutch and causing damage.

(3) The chain is constantly pressurized by the slider by the elastic force of the torsion spring attached to the arm of the tensioner, and while the one-way effect that prevents reversion prevents the chain from loosening, it is from the engine. The slider overtightens the chain due to the vibration of the chain, which has the effect of accelerating the life of the chain and the wear of the slider.

(4) There is a push rod that prevents backtracking from the lower part of the arm, and it is connected to the cono-shaped plate behind the lower part of the mounting plate, and that part is on the upper part of the rotation of the adjacent high-speed rotating clutch, so it is suitable for clutch design. There is a limit.

An object of the present invention is to reduce the impact load received on the chain with a simple structure to prevent damage to engine parts and to ensure stable operation of the engine.

The invention according to claim 1 is a cell motor side sprocket, a crank side sprocket on the crank shaft side of the engine, a chain wound around the cell motor side sprocket and the crank side sprocket, a bracket fixed to the engine body side, and a chain. It has a slider that guides the guide arm, a guide arm that is attached to the bracket, supports the slider, and swings with the slider, and a stopper means that suppresses the swing of the guide arm toward the bracket side.

The invention according to claim 2 is the invention according to claim 1, wherein the stopper means includes a fixing portion fixed to the bracket and one end portion inserted through the fixing portion to suppress the swing of the guide arm toward the bracket side. It is composed of a stopper bolt having an other end portion screwed to the fixed portion, and the stopper bolt is provided so that the swing width of the guide arm can be adjusted.

According to the present invention, the slider is attached to a bracket fixed to the engine body side so that the slider is in contact with the chain so that the slider can be swung. Suppress. As a result, even if the chain suddenly becomes tense when the engine is started or when the engine speed changes suddenly, the impact load applied to the chain by the slider and guide arm is alleviated, and the guide arm bounces more than necessary on the bracket side. Since the stopper means suppresses the damage, it is possible to prevent the parts from being damaged by interfering with the surrounding adjacent parts.

Further, the fixing portion is fixed to the bracket, one end of the stopper bolt inserted into the fixing portion suppresses the swing of the guide arm toward the bracket side, and the other end of the stopper bolt is screwed to the fixing portion. Therefore, the swing width of the guide arm can be arbitrarily adjusted by adjusting the position of the stopper bolt. As a result, even if the chain or slider is worn out due to aging and the position of the guide arm and the stopper bolt changes, the position of the stopper bolt is adjusted, and the swing width at which the guide arm is flipped toward the bracket is always kept constant. , Stable operation of the chain tensioner mechanism and improvement of life can be achieved.

FIG. 1 is a front view showing a chain tensioner mechanism inside an engine.

The slider is attached to a bracket fixed to the engine body side so that the slider is in contact with the chain so that the slider can swing. The stopper means suppresses the swing of the guide arm that swings with the slider to the bracket side by supporting the slider.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. FIG. 1 is a front view showing a chain tensioner mechanism inside an engine. In the figure, FR indicates the front of the vehicle, and UP in the figure indicates the upper part of the vehicle.

FIG. 1 illustrates the inside of the engine body 1 of a motorcycle, and includes the engine body 1, the crankcase 2, the starter motor side sprocket 3, the crank side sprocket 4, the chain 5, and the chain tensioner mechanism 6. , The clutch 7 is provided.

The starter motor side sprocket 3 is attached to the engine body 1 inside the crankcase 2. The crank-side sprocket 4 is attached to the engine body 1 inside the crankcase 2 and in front of and below the starter-side sprocket 3. The chain 5 is wound around the cell motor side sprocket 3 and the crank side sprocket 4 with a certain degree of looseness.

As shown in FIG. 1, the chain tensioner mechanism 6 includes a slider 8, a bracket 9, a guide arm 10, a spring 11, a fixing portion 12, a stopper bolt 13, and a nut 14.

The bracket 9 has a triangular shape, is arranged below the sprocket 3 on the starter motor side and behind the sprocket 4 on the crank side, and is fixed to the engine body 1 with bolts 9a.

The slider 8 is formed in a curved plate shape, is arranged between the chain 5 and the bracket 9, and is in contact with the slider upper surface 8a so as to guide the chain 5. Further, one end 8b of the slider is attached to the front end 9b of the bracket by a pin 15, and can swing up and down according to the tension of the chain 5. Further, the upper surface 8a of the slider is covered with a resin or the like so that the chain 8 rotates smoothly.

The guide arm 10 has a triangular shape, is arranged in front of the clutch 7 and behind and below the slider 8, and the front end of the guide arm is attached to the upper end of the bracket 9 with a pin 16. The guide arm 10 swings up and down in accordance with the swing of the slider 8 with the front end attached by the pin 16 as the rotation axis.

The spring 11 is, for example, a torsion spring, and is provided so as to be wound around a pin 16 to which the guide arm 10 and the bracket 9 are attached. Further, the lower end of the spring 11 is in contact with the bolt 9a for fixing the bracket 9 to the main body, and the upper end of the spring 11 is in contact with the guide arm 10 to push the guide arm 10 toward the chain 5.

The fixing portion 12 has a hollow square shape and is arranged in front of the clutch 7 and below the arm 10, and is fixed to the rear end of the bracket 9. Although not shown, the inner surface of the fixed portion has a female screw.

The stopper bolt 13 has a bolt shape and is arranged in front of the clutch 7 and below the guide arm 10. The lower end of the stopper bolt 13 is formed in a male screw shape, screwed into the fixing portion, and fixed by the nut 14. The upper end of the stopper bolt 13 is located between the lower end of the guide arm 10 and the fixing portion 12, and is provided at a position downward from the lower end of the guide arm 10. Further, the rear ends of the stopper bolt 13, the guide arm 10, the slider 8, the fixing portion 12, and the nut 14 are arranged so as to be arranged in a straight line vertically.

Next, the operation of the chain tensioner mechanism 6 according to the present embodiment will be described.

First, before starting the engine, the guide arm 10 is pushed up in the direction of the starter motor side sprocket 3 and the crank side sprocket 4 (upper front side) by the spring force of the spring 11, and the slider 8 pushes up the chain 5 by the guide arm 10. The chain 5 maintains a constant tension. Further, the stopper bolt 13 is arranged below the guide arm 10 and is adjusted by the nut 14 so that the upper end of the stopper bolt 13 is located at a position separated from the guide arm 10 by about 1.5 to 2 mm.

Next, when the engine is started, the starter motor side sprocket 3 rotates clockwise by operating a starter motor (not shown). Due to this rotation, the chain 5 tries to rotate the crank side sprocket 4 clockwise, and tension is generated on the chain 5, and the chain 5 projects rearward and downward in the rotation section from the crank side sprocket 4 to the cell motor side sprocket 3 side. Is done. At this time, when a force exceeding the spring force of the spring 11 is applied to the guide arm 10, the slider 8 in contact with the chain 5 is pushed backward and downward, and the guide arm 10 in contact with the slider 8 is pushed backward and downward. The guide arm 10 swings toward the stopper bolt 13. When the guide arm 10 swings toward the stopper bolt 13, the lower end of the guide arm 10 comes into contact with the upper end of the stopper bolt 13, and the swing downward and rearward of the guide arm 10 is suppressed. When the force that projects backward and downward from the chain 5 weakens due to a change in engine speed or the like, the guide arm 10 and the slider 8 push the chain 5 forward and upward again by the spring 11 to maintain the chain 5 at a constant tension.

Further, during running after the engine is started, the tension applied to the chain 5 changes in the rotation section from the crank side sprocket 4 to the cell motor side sprocket 3 side according to the engine speed, but the guide arm 10 and the slider are changed by the spring 11. The state in which the 8 pushes the chain 5 forward and upward to maintain the chain 5 at a constant tension and the state in which the chain 5 protruding rearward and downward is suppressed by the stopper bolt 13 are repeated.

According to the present embodiment, the chain tensioner mechanism 6 maintains the chain 5 so as to have a constant tension, and even if the chain 5 is suddenly tensioned when the engine is started or when the engine speed is suddenly changed. Since the stopper bolt 13 suppresses the impact load applied to the chain 5 by the slider 8 and the guide arm 10 and prevents the guide arm 10 from being repelled toward the bracket 9 side more than necessary, for example, peripheral parts such as the clutch 7 are adjacent to each other. It is possible to prevent damage between parts by interfering with each other.

Further, since the stopper bolt 13 is screwed to the fixing portion 12 with the nut 14, even if the chain 5 or the slider 8 is worn out due to aged deterioration and the arm 10 is separated above the stopper bolt 13, the stopper bolt 13 is used. Can be maintained at a constant width by adjusting the position of the guide arm 10 upward so that the guide arm 10 is flipped toward the bracket 9, and the chain tensioner mechanism 6 can be stably operated and its life can be improved.

Further, since the guide arm 10, the slider 8, the stopper bolt 13, the fixing portion 12, and the rear ends of the nut 14 are arranged so as to be linearly arranged in the vertical direction, the clutch arranged behind the chain tensioner mechanism 6. A space can be secured between the vehicle and the engine to increase the degree of freedom in engine design.

Although the embodiments made by the present invention have been described above with reference to the drawings, the present invention is not limited by the description and the drawings which form a part of the disclosure of the present invention. For example, the stopper bolt 13 does not have to be bolt-shaped. Further, the stopper bolt 13 and the fixing portion 12 may be integrally formed with the bracket 9.

Further, although the example in which the slider 8 and the guide arm 10 are separately provided and swings in conjunction with the overhang of the chain 5 has been described, the slider 8 and the arm 10 can be integrally provided so as to swing according to the overhang of the chain 5. It may be provided as follows.

1 Engine 2 Crankcase 3 Starter sprocket 4 Crank side sprocket 5 Chain 6 Chain tensioner mechanism 7 Clutch 8 Slider 8a Slider top surface 8b Slider end 9 Bracket 9a Bolt 9b Bracket front end 10 Guide arm 11 Spring 12 Fixing part (stopper means)
13 Stopper bolt (stopper means)
14 nut 15 pin 16 pin

Claims (2)

With the sprocket on the starter motor side,
The crank side sprocket on the crank shaft side of the engine and
The chain wound around the starter sprocket and the crank sprocket,
Brackets fixed to the engine body side
A slider that swings against the bracket and guides the chain,
A guide arm that is attached to the bracket, supports the slider, and swings with the slider.
Chain tensioner mechanism consisting of stopper means to suppress swing to the mounting bracket side of the guide arm The stopper means is a fixing part fixed to the bracket and
It consists of a stopper bolt having one end portion inserted through the fixing portion to suppress the swing of the guide arm toward the bracket side and the other end portion screwed to the fixing portion, and the stopper bolt adjusts the swing width of the guide arm. The chain tensioner mechanism according to claim 1, wherein the chain tensioner mechanism is provided so as to be possible.

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