JP4437702B2 - Endless belt tension adjuster - Google Patents

Description

  The present invention relates to an apparatus for adjusting the tension of an endless belt wound around a plurality of pulleys in an internal combustion engine or the like.

  As is well known, this type of tension adjusting device in the prior art is provided with one pulley among a plurality of pulleys around which an endless belt is wound, or a tension pulley in contact with the endless belt, provided on an adjuster bracket. The guide unit is configured to move in a direction in which the tension in the endless belt is increased or decreased, and the pulley is an adjuster mounted between the bolt insertion part provided in the adjuster bracket and the pulley. The tension of the endless belt is adjusted by moving along the guide portion by turning a bolt.

  However, this conventional tension adjusting device applies the tension of the endless belt to the endless belt when the adjustment bolt is tightened by tightening the adjustment bolt as described above. There is a high risk of excessive tightening in which the tension exceeds the limit of strength in the endless belt and / or the bearing of each pulley.

  Further, Patent Document 1 is configured such that a guide hole which is a guide portion in the adjuster bracket is extended to the bolt insertion portion. However, Patent Document 1 includes the adjuster bracket and the bolt. Since there is no description of plastic deformation of the insertion portion, excessive tightening that exceeds the limit of strength cannot be prevented.

  Therefore, Patent Document 2 as a prior art provides the adjustment bolt by providing a clutch mechanism in the middle portion of the adjustment bolt so that when the tightening torque of the adjustment bolt exceeds a predetermined value, the adjustment bolt idles. It proposes to avoid excessive tightening on the bolts.

Further, another Patent Document 3 proposes that a thin wall portion is provided at a portion between a base end portion for attaching the adjuster bracket to an internal combustion engine or the like and a guide portion of the adjuster bracket. According to this configuration, when the tightening torque exceeds a predetermined value during tightening with the adjustment bolt, the thin wall portion is plastically deformed, so that excessive tightening with the adjustment bolt can be avoided.
JP 2003-21203 A Japanese Utility Model Publication No. 60-51344 JP-A-9-119318

  However, in Patent Document 2, since the adjustment bolt is provided with a clutch mechanism, the structure is complicated and the number of parts increases, so that not only the manufacturing price is greatly increased but also the size and weight are increased. There was a problem of being invited.

  In addition, according to Patent Document 2, during the tightening operation of the adjustment bolt, when the clutch mechanism is disengaged, the tightening torque with respect to the adjustment bolt rapidly decreases, so that the operator may feel uneasy or uncomfortable. It was big.

  On the other hand, according to Patent Document 3, although excessive tightening can be avoided by plastic deformation of the thin wall portion of the adjustment bolt, the relative position of the pulley guided by the guide portion of the adjustment bolt with respect to other pulleys is the thin wall portion. There is a problem in that the endless belt wound around these pulleys may come off from the pulleys because they are displaced by plastic deformation of the parts.

  It is a technical object of the present invention to provide a tension adjusting device capable of avoiding excessive tightening of the adjusting bolt by an extremely simple mechanism.

In order to achieve this technical problem, claim 1 of the present invention provides:
“A direction in which the tension of the endless belt is increased or decreased by using one of a plurality of pulleys around which the endless belt is wound, or a tension pulley that is in contact with the endless belt, with a guide portion provided on an adjuster bracket. The pulley is configured to move along the guide portion by turning an adjustment bolt installed between the bolt insertion portion provided on the adjuster bracket and the pulley. In the tension adjusting device consisting of
When the tension of the endless belt exceeds a predetermined value when tightening the adjuster bolt, the bolt insertion portion applies the tension of the endless belt to the portion of the adjuster bracket between the guide portion and the bolt insertion portion. A plastically deformed portion that is displaced in the loosening direction is provided. "
It is characterized by that.

Further, claim 2 of the present invention provides
“In the description of claim 1, the bolt insertion portion is provided at the tip of a portion where one end portion of the adjuster bracket is bent at a right angle, while the plastic deformation portion is provided in the bent portion.”
It is characterized by that.

  When applying tension to the endless belt by tightening the adjuster bolt, if the tension in the endless belt exceeds a predetermined value, the adjuster bracket is a plastic deformation portion of the adjuster bracket, and the bolt insertion portion is the endless belt. It will be plastically deformed so as to be displaced in the direction of loosening the tension.

  Therefore, the operator tightening the adjuster bolt may stop the tightening when the plastic deformation occurs, and the rate of increase in tension in the endless belt due to the tightening of the adjuster bolt is determined by the plastic deformation. Since the plastic deformation is lower than before the plastic deformation occurs, the tension on the endless belt becomes excessively high, and the size and weight are increased with an extremely simple configuration in which a plastic deformation portion is provided on the adjuster bracket. Can be surely prevented without inviting.

  In addition, since the tightening torque of the adjuster bolt does not change greatly before and after the deformation, the anxiety or uncomfortable feeling given to the operator can be reduced.

  In addition, the place where the bolt insertion portion is plastically deformed so as to be displaced in the direction of loosening the tension of the endless belt is a plastic deformation portion between the guide portion and the bolt insertion portion of the adjuster bracket, Since the relative position of the pulley guided by the guide portion with respect to the other pulleys is not displaced at all, the endless belt does not come off from the pulley.

  In particular, the configuration described in claim 2 has an advantage that the above-described effect can be achieved by a simpler configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIGS. 1 to 3 show a first embodiment. This first embodiment transmits the rotation of the crankshaft 2 in the internal combustion engine 1 to an engine accessory such as an alternator 3. This is a case where the present invention is applied to an endless belt 6 wound between an output pulley 4 on the shaft 2 and an input pulley 5 in the alternator 3.

  In the first embodiment, the alternator 3 is pivotally attached to the internal combustion engine 1 by a pin shaft 7 at the upper end of an arm 3a protruding upward from the upper surface thereof.

  An adjuster bracket 8 made of a metal plate that extends laterally through the lower side of the alternator 3 is fixed to the internal combustion engine 1 by fastening a fixing bolt 9. The endless belt 6 is attached to the adjuster bracket 8. A long groove-shaped guide hole 10 serving as a guide portion for moving one pulley 5 of a plurality of wound pulleys in a direction in which tension in the endless belt 6 is increased or decreased is provided on the pin shaft 7. It is drilled so as to extend in an arc shape with the center at the center.

  The arm 11 projecting downward from the lower surface of the alternator 3 is configured to be fastened to the adjuster bracket 8 with a bolt 12 that is movably inserted in the guide hole 10 of the adjuster bracket 8 in its longitudinal direction. Has been.

  Further, a bolt insertion portion 13 formed by bending a part of the adjuster bracket 8 at a right angle is provided at the front end portion of the adjuster bracket 8, and a head adjuster bolt 15 is provided in the bolt hole 14 in the bolt insertion portion 13. An adjuster bolt 15 is inserted so as to be screwed into a nut member 16 attached to the fixing bolt 12, and by tightening the adjuster bolt 15, the alternator 3, and eventually the input pulley 5 in the alternator 3, is inserted into the crankshaft. The endless belt 6 is moved in a direction away from the output pulley 4 and tensioned on the endless belt 6, and in other words, tension is applied to the endless belt 6.

  In the adjuster bracket 8, a bent portion 17 that is bent at a right angle between the guide hole 10 and the bolt insertion portion 13 is provided with a punch hole 18, and the strength at the bent portion 17 is partially increased. When tightening the adjuster bolt 15 by weakening, when the tension in the endless belt 6 exceeds a predetermined value, the adjuster bracket 8 is bent at the bent portion 17 as shown by a two-dot chain line in FIG. In other words, the bolt insertion portion 13 is configured to be plastically deformed so as to be displaced to a position where the tension in the endless belt 6 is relaxed in a direction approaching the fixing bolt 9.

  According to this configuration, when the tensioner bolt 15 is tightened, when the tension in the endless belt 6 exceeds a predetermined value, the adjuster bracket 8 is bent at the bent portion 17 as shown by a two-dot chain line in FIG. The bolt insertion portion 13 is plastically deformed so as to be displaced in the direction of the fixing bolt 9, that is, in a position where the tension in the endless belt 6 is relaxed.

  When this plastic deformation occurs, the operator may stop the tightening operation of the adjuster bolt 15, and the rate of increase in the tension in the endless belt 6 due to the tightening of the adjuster bolt 15 is due to the plastic deformation described above. , It will be lower than before this plastic deformation occurs.

  In addition, the relative position of the pulley 5 guided along the guide hole 10 in the adjuster bracket 8 with respect to the other pulley 4 is not displaced by the plastic deformation.

  In addition, the tension adjusting operation on the endless belt 6 is performed in a state where the fixing bolt 12 is loosened, and after the adjustment, the fixing bolt 12 is strongly tightened so that the pulley 5 does not move.

  In the first embodiment, the strength in the bent portion 17 is weakened by punching the punch hole 18 and plastic deformation is performed in this portion. The present invention is not limited to this, and only the bent portion 17 may be partially thinned to weaken its strength so that the portion is plastically deformed.

  Further, as in the second embodiment shown in FIG. 4, the bent portion that is bent at a right angle may be a loop-shaped bent portion 17 ′, and the portion may be plastically deformed.

  Furthermore, as in the third embodiment shown in FIG. 5, the portion of the adjuster bracket 8 between the guide hole 10 and the bent portion 17 or the fourth embodiment shown in FIG. As described above, grooves 19 and 20 are provided in the portion of the adjuster bracket 8 between the bent portion 17 and the bolt insertion portion 13 so as to be partially thinned, or a hole is formed. Therefore, the strength may be reduced by this and plastic deformation may be performed in this portion.

  Next, FIG. 7 shows a fifth embodiment.

  In the fifth embodiment, the bolt insertion portion 13 'through which the adjuster bolt 15 passes is separated from the adjuster bracket 8', and the bolt insertion portion 13 'is separated from the adjuster bracket 8'. The screw shaft 21 is attached so as to rotate around the axis of the screw shaft 21. In this case, a groove is formed in a portion of the adjuster bracket 8 'adjacent to the bolt insertion portion 13'. It is possible to obtain the same effect as described above by providing the structure 22 so as to be partially thinned, or by making the strength weak by, for example, making a punched hole and plastically deforming in this part. .

  The above embodiment is applied to the endless belt 6 for transmitting power from the crankshaft 2 to the alternator 3 in the internal combustion engine. However, the present invention is not limited to this, and the endless belt is wound. The same applies when one pulley among a plurality of pulleys that are hung or a tension pulley that is in contact with the endless belt is directly attached to the fixing bolt 9 and these pulleys are moved by the adjuster bolt. Needless to say, it can be applied to the above.

It is a front view which shows 1st Embodiment. FIG. 2 is a partially cutaway sectional view taken along the line II-II in FIG. 1. FIG. 3 is an enlarged side view taken along line III-III in FIG. 2. It is a principal part enlarged view which shows 2nd Embodiment. It is a principal part enlarged view which shows 3rd Embodiment. It is a principal part enlarged view which shows 4th Embodiment. It is a principal part enlarged view which shows 5th Embodiment.

Explanation of symbols

4,5 Pulley 6 Endless belt 8, 8 'Adjuster bracket 10 Guide hole 13, 13' Bolt insertion part 14 Bolt hole 15 Adjuster bolt 17, 17 'Bent part 18 Extract hole

Claims (2)

One of a plurality of pulleys around which an endless belt is wound, or a tension pulley that is in contact with the endless belt, in a direction to increase or decrease the tension of the endless belt with a guide provided on an adjuster bracket. The pulley is configured to move, and the pulley is configured to move along the guide portion by turning an adjusting bolt mounted between the bolt insertion portion provided on the adjuster bracket and the pulley. A tension adjusting device comprising:
When the tension of the endless belt exceeds a predetermined value when tightening the adjuster bolt, the bolt insertion portion applies the tension of the endless belt to the portion of the adjuster bracket between the guide portion and the bolt insertion portion. A tension adjusting device for an endless belt, characterized in that a plastically deforming portion that is displaced in a loosening direction is provided.   2. The tension adjustment of an endless belt according to claim 1, wherein the bolt insertion portion has a shape in which one end portion of the adjuster bracket is bent at a right angle, and the plastic deformation portion is provided in the bent portion. apparatus.

Images