JPS6235961Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a belt tension device for applying a predetermined tension to a fan belt for driving a cooling fan of an internal combustion engine.

<Prior art> Among internal combustion engines such as diesel engines,
In particular, in water-cooled internal combustion engines in which engine cooling water is cooled by heat exchange with air in a radiator, a cooling fan attached to the engine output shaft is usually used to drive a cooling air generation fan installed in the radiator during engine operation. A fan belt is formed by winding a fan belt between a fan drive pulley, a fan pulley attached to the cooling fan, and a tension pulley disposed between both pulleys, and supporting the tension pulley so that its position can be adjusted. A belt tension device is attached to apply appropriate tension to the fan belt to ensure power transmission by the fan belt.

However, the belt tension device installed in the above-mentioned conventional internal combustion engine generally has a tension pulley attached to the free end side of the tension lever, which is fixed to the engine body by tightening one end together with a bolt. The position of the tension pulley was changed by changing the mounting angle of the tension lever.However, in the belt tension device of the conventional structure, when adjusting the tension, the bolt must be used with a spanner, etc. While loosening the fan belt with the tool, at the same time tilt the tension lever with one hand to adjust the tension on the fan belt, hold this position and tighten the bolt again with the other hand. In addition, since this series of operations cannot be performed without using both hands, it is not possible to check the tension of the fan belt during adjustment, which makes adjustment work extremely frequent, and the tension is too high when tightening bolts. There was a problem in that the attachment angle of the tension lever changed and the tension lever could not be fixed at an accurate position.

In order to overcome this inconvenience, for example, as shown in FIG. A bolt 5 inserted into an arcuate long hole 4 formed at the tip of the tension lever 2 is screwed into the side surface of the cylinder body 6, and one end is fixed to the tension lever 2 near the attachment position of the tension pulley 3. The tip of a butterfly bolt 10 rotatably supported by a support stay 9 attached to a cylinder head 8 is screwed onto the tip of the arm 7, and the relative threading amount between the butterfly bolt 10 and the arm 7 is changed. By doing this, the mounting angle of the tension lever 2 is changed, and by tightening the bolt 5, the tension lever 2 is fixed to the cylinder body 6 and the angle is maintained. 54−
Although proposed in Japanese Patent No. 107737, a belt tension device having such a structure requires a considerable number of parts, leading to a rise in engine manufacturing costs. Since the bolts 5 are also surrounded by the flywheel cover 12, it is necessary to remove the flywheel cover 12 each time when tightening the bolts 5, which has the problem of complicating the work. It left room for what should be done.

<Purpose of the invention> The present invention focuses on the problem of the difficulty of tension adjustment that such conventional belt tension devices had, and the problem of rising engine manufacturing costs due to an increase in the number of parts, and developed a tension pulley support. By constructing the tension lever with a single lever that can be moved in the longitudinal direction, and fixing the tension lever with bolts placed outside the flywheel cover, the number of parts can be reduced and the tension can be adjusted. The purpose is to make the work easier and to solve the problems mentioned above.

<Structure of the invention> The structure of the invention to achieve the above object includes a cooling fan drive pulley that is integrally fixed to the flywheel, a fan pulley that is fixed to the cooling fan,
The cooling fan is mounted on a cooling fan drive mechanism for an internal combustion engine, in which a fan belt is wound between the tension pulley provided between both pulleys, and the flywheel and tension pulley are housed in a flywheel cover. A tension lever is disposed near the fan drive pulley, and the tension lever has a threaded hole along the longitudinal direction at the rear end, a support shaft perpendicular to the longitudinal direction at the front end side, and an intermediate longitudinal direction. The tension pulley is rotatably supported by the support shaft thereof, and the tip of an adjustment bolt screwed toward the front end side into the threaded hole of the tension lever is connected to the cylinder body. It rotatably engages in a fulcrum hole provided in a fixed part such as a cylinder head, makes contact with the bottom of the fulcrum hole, and also inserts a fixing bolt into the elongated hole of the tension lever for the length of the lever. the fixing bolt is inserted so as to be relatively movable along the direction, and the tip of the fixing bolt is screwed to the wall surface of the fixing part outside the flywheel cover,
The tension lever is clamped between the head of the fixing bolt and the fixing part, and the tension lever is fixed to the fixing part.

<Example> Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

FIG. 2 is a side view showing an example of a horizontal internal combustion engine to which the belt tension device of the present invention is applied, and FIG. 3 is a plan view of the engine.

In each of these figures, 21 is a cylinder body,
22 is a cylinder head fixed to the front surface of the cylinder body 21, 23 is a valve arm bonnet attached to the front surface of the cylinder head 22, and 24 is an air cleaner connected to the intake port of the cylinder head 22 via an intake pipe 25. , 26 is an exhaust muffler, 2 provided on the opposite side of the air cleaner 24.
7 is a fuel tank placed on the top surface of the cylinder body 21; 28 is a radiator placed on the top surface of the cylinder body 21 adjacent to the fuel tank 27; A cooling fan 30 to which is fixed is rotatably supported.

Further, a flywheel 3 to which a fan drive pulley 32 is fixed is attached to the end of the engine output shaft 31 that protrudes horizontally from the non-control side of the cylinder body 21.
3 is attached, and the flywheel 33 is surrounded by a flywheel cover 34 fixed to the non-control side of the cylinder body 21, and the fan pulley 2 of the cooling fan 30 is
9 and the fan drive pulley 32 has a cross section V.
A letter-shaped fan belt 35 is wrapped around it.

On the other hand, 36 is a tension lever provided near the fan drive pulley 32 on the non-controlling side of the cylinder body 21, and the tension lever 36 has a support shaft 37 at one end 36a that is perpendicular to the longitudinal direction. The tension pulley 38 is rotatably supported via a bearing, and the fan belt 35 is wound around the tension pulley 38, and the other end 36b is bent approximately at right angles. The adjustment bolt 41 is screwed into a screw hole 40 formed in the bent portion 39.

Note that the adjustment bolt 41 has its tip 41
A is rotatably engaged in a shallow fulcrum hole 42 bored in the front surface 21a of the cylinder body 21 at a position that does not interfere with the cylinder head 22, and is in contact with the bottom of the fulcrum hole 42.

Further, the tension lever 36 has an elongated hole 43 extending in the longitudinal direction in its middle portion, and the tip of the fixing bolt 44 inserted into the elongated hole 43 is attached to the outside of the flywheel cover 34. The tension lever 36 is screwed into a screw hole 45 provided on the side surface of the cylinder body 21 in the figure, and the lateral movement of the tension lever 36 is restricted by the head of the fixing bolt 44.

The belt tension device of the present invention has the above-mentioned configuration. Next, its operation will be explained. First, when increasing the tension of the fan belt 35, the flywheel cover 34 is left attached. Loosen the fixing bolt 44, rotate the adjustment bolt 41, move the tension lever 36 in the direction of arrow X in FIG. 2, and by moving the tension pulley 38, the tension acting on the fan belt 35 reaches the specified value. At this point, the rotation operation of the adjustment bolt 41 is stopped, and the fixing bolt 44 is tightened to fix the tension lever 36 to the cylinder body 21.

Furthermore, when loosening the fan belt 35, it is sufficient to loosen the fixing bolt 44, rotate the adjustment bolt 41 in the opposite direction, and move the tension lever 36 and tension pulley 38 in the direction of arrow Y.

In addition, in the above embodiment, the adjustment bolt 41
Although the cylinder body 21 is provided with a fulcrum hole 42 for holding the tip 41a of the fulcrum hole 42, the location where the fulcrum hole 42 is formed is not limited to this.
It is also possible to provide the fulcrum hole 42 on the front surface of the cylinder head 22 and to slightly extend the rear end 36b side of the tension lever 36 to engage the adjustment bolt 41 in the fulcrum hole 42. That is, the fulcrum hole 42 can be The same effect can be achieved even if the fixing part is provided on any fixed part including the cylinder body 21 and the cylinder head 22.

<Effects of the invention> As described above, the belt tension device of the invention has a tension pulley attached to one end of one tension lever supported movably along the length, and At the same time, screw the adjustment screw for adjusting the position of the tension pulley to the other end protruding from the side, and tighten the fixing bolt inserted into the elongated hole in the middle of the tension lever to attach the tension lever to the cylinder body. Since the belt tensioner is fixed to secure the mounting position, there is no need to remove the flywheel cover each time the belt tension is adjusted, unlike conventional belt tensioners, making work easier and more efficient. In addition, since the belt tension adjustment work can be performed with one hand, it is possible to accurately proceed with the adjustment work while checking the tension of the fan belt with the other hand.

[Brief explanation of the drawing]

Fig. 1 is a side view of a horizontal internal combustion engine equipped with a conventional belt tension device, Fig. 2 is a side view of a horizontal internal combustion engine to which the belt tension device of the present invention is applied, and Fig. 3 is an outline of the engine. FIG. 21, 22... Fixed part, 29... Fan pulley, 30... Cooling fan, 32... Fan drive pulley, 33... Flywheel, 34... Flywheel cover, 35... Fan belt, 36...
... Tension lever, 37 ... Support shaft, 38 ... Tension pulley, 40 ... Screw hole, 41 ... Adjustment bolt, 42 ... Fulcrum hole, 43 ... Long hole, 44 ...
...Fixing bolt.

Claims (1)

[Scope of utility model registration request] A fan belt is wound between a cooling fan drive pulley that is integrally fixed to the flywheel, a fan pulley that is fixed to the cooling fan, and a tension pulley provided between both pulleys, and the flywheel and tension pulley are In a cooling fan drive mechanism for an internal combustion engine housed in a flywheel cover, a tension lever is disposed near the cooling fan drive pulley, and the tension lever has a threaded hole extending in the longitudinal direction at its rear end. have,
A support shaft perpendicular to the longitudinal direction is provided on the front end side, and an elongated hole is provided in the intermediate longitudinal direction, and the tension pulley is rotatably supported by the support shaft,
The tip of an adjustment bolt screwed toward the front end side of the threaded hole of the tension lever is rotatably engaged in a fulcrum hole provided in a fixed part of the cylinder body, cylinder head, etc. At the same time, a fixing bolt is inserted into the elongated hole of the tension lever so as to be relatively movable along the length direction of the lever, and the tip of the fixing bolt is fixed on the outside of the flywheel cover. An internal combustion engine characterized in that the tension lever is screwed onto a wall surface of the fixing bolt, the tension lever is clamped between the head of the fixing bolt and the fixing part, and the tension lever is fixed to the fixing part. belt tension device.