JP6593079B2 - Tension adjuster - Google Patents

Description

  The present invention relates to a tension adjusting device, and more particularly, to a tension adjusting device that prevents damage to a shaft hole of a bracket even if the bracket that supports a pulley that can adjust the position of a rotating shaft with a cantilever is reduced in weight. .

  The rotational power of the crankshaft of the engine is transmitted to the auxiliary machine via an endless belt or chain. As a device for adjusting the tension of the endless object, the pulley includes a pulley that rotates in contact with an endless belt or chain, and a bracket having a shaft hole into which the rotation shaft is inserted. Has been proposed (see, for example, Patent Document 1). In addition, as this auxiliary machine, an air pump, an alternator, a hydraulic pump, etc. can be illustrated.

  In this apparatus, a bracket for supporting the pulley in a cantilever state is formed in a thin plate shape. On the other hand, some devices of this type reinforce the strength when attached to the outside of the engine or the like by forming the bracket thicker than a thin plate. Thus, it becomes possible to attach a plurality of pulleys to one bracket by making the bracket thicker than a thin plate.

  By the way, recent engines have attempted to improve fuel efficiency by reducing the weight. The object of this weight reduction includes the tension adjusting device having the pulley described above. Therefore, it is desired that the bracket for supporting the pulley in a cantilever state is made of a metal having a small specific gravity. Examples of the metal having a small specific gravity include aluminum and aluminum alloys. In particular, a bracket formed thicker than a thin plate is made of a metal having a small specific gravity, which is advantageous for weight reduction.

  However, the shaft hole of the bracket also serves as a detent when the rotating shaft of the pulley is fixed. And metal with small specific gravity is soft (low hardness). Therefore, if this bracket is made of aluminum, aluminum alloy, or the like, the shaft hole of the bracket may be damaged due to the load from the rotary shaft to the bracket during rotation prevention.

JP-A-5-87200

  An object of the present invention is to provide a tension adjusting device that can prevent damage to a shaft hole of a bracket even if the bracket that supports a pulley that can adjust the position of a rotating shaft in a cantilever manner is lightened. .

  The tension adjusting device of the present invention that achieves the above object includes a pulley having a rotating shaft and rotating in contact with an endless object or a cord-like object, a bracket having a shaft hole formed in an elongated hole, and a A slide member that is movable in the longitudinal direction of the shaft hole and has a positioning hole, and the slide member is stacked on the bracket so that the opening of the positioning hole overlaps a part of the opening of the shaft hole. The rotation shaft is fixed to the bracket and the slide member in a state in which the rotation shaft is inserted into both the shaft hole and the positioning hole, so that the position of the rotation shaft of the pulley is the position of the shaft hole. In the tension adjusting device configured to be adjustable in the longitudinal direction, the slide member is made of a material harder than the bracket and protrudes in the radial direction from the rotating shaft of the pulley. The detent portion is inserted through at least the positioning hole, and the positioning hole is formed in a shape that prevents the detent portion from fitting when the rotation shaft rotates in the circumferential direction. It is characterized by that.

  According to this tension adjusting device, the positioning hole formed in the slide member made of a material harder than the bracket is fitted with the non-rotating portion when the rotation shaft of the pulley rotates in the circumferential direction, thereby preventing the rotation. By forming in the shape which becomes, interference with the shaft hole of a bracket and the rotation-stop part of a rotating shaft can be avoided. As a result, even if the bracket is made of a metal with a small specific gravity and the weight of the device is reduced, the role of the non-rotating mechanism with respect to the rotating shaft of the pulley is transferred from the shaft hole of the bracket to the positioning hole of the slide member. Since it can prevent damaging, the fall of durability accompanying weight reduction can be controlled.

  In particular, it is desirable that the tension adjusting device is provided in the engine. This tension adjusting device can adjust the tension of the endless belt or chain connected to the crankshaft of the engine with high accuracy by adjusting the position of the rotating shaft of the pulley by sliding the slide member. . Further, since the role of the non-rotating mechanism with respect to the rotating shaft of the pulley is removed from the role of the shaft hole of the bracket, the bracket can be made of a metal having a small specific gravity, and the engine can be reduced in weight, which is advantageous in improving fuel consumption.

It is a lineblock diagram illustrating the engine provided with the tension adjustment device of the embodiment of the invention. It is a top view which illustrates the tension adjustment apparatus of FIG. It is sectional drawing shown by the arrow direction III of FIG. It is sectional drawing which illustrates the state which moved the position of the slide member from the state of FIG. It is a top view which illustrates the state which a rotating shaft tends to rotate from the state of FIG. FIG. 3 is a plan view in which a fixing nut and a slide member in FIG. 2 are omitted. FIG. 3 is a plan view in which the fixing nut of FIG. 2 is omitted. FIG. 6 is an enlarged view in which a rotation preventing portion and a positioning hole in FIG. 5 are enlarged.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 illustrates an engine 10 including a tension adjusting device 16 according to an embodiment of the present invention.

  In the engine 10, the power generated by the combustion of fuel inside the engine body 11 is converted into rotational power by the crankshaft 12. This rotational power is transmitted from the crank pulley 13 fixed to the crankshaft 12 to each auxiliary machine 15 via the endless belt 14 to drive each auxiliary machine 15. At this time, the tension of the belt 14 is adjusted by the tension adjusting device 16. Examples of the auxiliary machine 15 include an air pump, an alternator, and a hydraulic pump.

  The tension adjusting device 16 of the embodiment will be described by taking an example of a device that adjusts the tension of the belt 14 of the engine 10, but a chain may be used instead of the belt 14 as an endless object. Moreover, as the tension adjusting device 16, other than this, a device for adjusting the tension of the cord-like object wound around the drum can be exemplified.

FIG. 2 illustrates the plane of the tension adjustment device 16. FIG. 3 illustrates a cross section shown in the direction of arrow III in FIG. The tension adjusting device 16 includes a pulley 20, a bracket 30, and a slide member 40.

  In addition, below, a long hole can illustrate a rectangular hole and the rounded rectangular hole which rounded the corner | angular of the rectangle. In this embodiment, as an elongate hole, an explanation will be given by taking, as an example, a hole having two parallel lines of equal length and two semicircles, and two semicircles facing each other in the longitudinal direction. To do.

  The pulley 20 has a sheave 21, a bearing 22, and a rotating shaft 23. The sheave 21 is formed in a cylindrical shape or a disk shape, and is rotatably supported on the rotary shaft 23 via a bearing 22. It is preferable to provide grooves or protrusions on the radial surface of the sheave 21 so that endless objects and cords do not slide on the surface or shift in the axial direction of the rotary shaft 23.

  The rotating shaft 23 includes a fixed portion 24 having a male screw at one end, a retaining portion 25 having the other end projecting in the radial direction, and a shaft portion 26. The shaft diameter of the fixing portion 24 is preferably smaller than the shaft diameter of the shaft portion 26, and the shaft diameter of the retaining portion 25 is preferably larger than the shaft diameter of the shaft portion 26.

  The bracket 30 is made of a metal having a specific gravity of 3.0 or less, and includes a web 31, a flange 32, a stiffener 33, and mounting holes 34 and 35. Examples of the metal having a specific gravity of 3.0 or less include aluminum and aluminum alloys.

  As described above, the bracket 30 is formed of a metal having a small specific gravity, so that the weight of the bracket 30 can be reduced. In addition, since the bracket 30 includes not only the thin plate-like web 31 but also the flange 32 and the stiffener 33 extending in the vertical direction from the web 31, the rigidity is increased and the durability can be improved. By improving the rigidity, another pulley can be attached by screwing the rotation shaft into the attachment hole 35. Furthermore, the thickness of the attachment hole 34 is increased by increasing the overall thickness by the flange 32 and the stiffener 33. Thereby, since the fastening force of a mounting bolt can be enlarged, the intensity | strength at the time of attaching this bracket 30 to the engine 10 can be reinforced.

  In the web 31, a slide groove 36 in which the slide member 40 slides and a shaft hole 37 into which the rotation shaft 23 of the pulley 20 is inserted are formed on the opposite surface of the pulley 20. The shaft hole 37 is a long through hole.

  The slide member 40 includes a main body 41 that can move in the longitudinal direction of the shaft hole 37 and a bolt 42 that fixes the main body 41. The main body 41 is formed in a plate shape that fits into the slide groove 36. Further, a moving hole 43 in which a female screw extending in the longitudinal direction is formed at one end portion in the longitudinal direction of the main body 41 and a positioning hole 44 into which the rotating shaft 23 of the pulley 20 is inserted at the other end portion. It is formed.

  The tension adjusting device 16 includes a fixing nut 50, a collar 51, and a washer 52 for fixing the rotating shaft 23. The fixing nut 50 is screwed into the fixing portion 24 of the rotating shaft 23. An example of the fixing nut 50 is a flange nut having a flange larger than the inner periphery of the positioning hole 44 of the slide member 40. As the fixing member, either the collar 51 or the washer 52 may be used. The collar 51 is disposed on the bracket 30 side of the shaft portion 26 between the retaining portion 25 and the rotation preventing portion 27. The diameter of the collar 51 or the diameter of the washer 52 is preferably at least larger than the length of the shaft hole 37 of the bracket 30 in the width direction.

In the tension adjusting device 16, the bolt 42 is screwed into the movement hole 43 of the main body 41 in a state where the bolt 42 is inserted from the outside into the bolt hole 38 formed in the flange 32 of the bracket 30. By screwing the bolt 42 and the movement hole 43, the slide member 40 is laminated and fixed to the bracket 30 so that the opening of the positioning hole 44 overlaps a part of the opening of the shaft hole 37.

  The rotating shaft 23 of the pulley 20 is inserted through both the shaft hole 37 of the bracket 30 and the positioning hole 44 of the slide member 40 with the fixing portion 24 at the head. A fixing nut 50 is screwed to the fixing portion 24. Thereby, the rotating shaft 23 is fixed to the bracket 30 and the slide member 40 in a state where the bracket 30 and the slide member 40 are sandwiched between the fixing nut 50 and the fixing member composed of the collar 51 and the washer 52.

  The bracket 30 is fixed to the engine 10 or the periphery of the engine 10, and the pulley 20 contacts the endless belt 14 connected to the crankshaft 12 of the engine 10.

  The bracket 30 and the slide member 40 may be laminated and fixed so that the sheave 21 of the pulley 20, the slide member 40, and the bracket 30 are arranged in this order. Further, the collar 51 and the washer 52 are not necessarily provided, and may be omitted as long as the rotary shaft 23 is fixed to the bracket 30 and the slide member 40 without being provided.

  FIG. 4 illustrates a state in which the position of the slide member 40 in FIG. 3 is changed. Thus, in this tension adjusting device 16, the position of the slide member 40 is changed by changing the position of the tip of the bolt 42 in the movement hole 43, and the position of the rotary shaft 23 of the pulley 20 is changed to the shaft hole of the bracket 30. 37 can be adjustable in the longitudinal direction. Thereby, the tension of the endless belt 14 in contact with the pulley 20 can be adjusted with high accuracy.

  In such a tension adjusting device 16, the slide member 40 is made of a material harder than the bracket 30. The material harder than the bracket 30 is preferably Vickers hardness of 200 HV or higher. Then, as a material which comprises this slide member 40, carbon steel can be illustrated.

  Further, the rotation shaft 23 of the pulley 20 is formed with an anti-rotation portion 27 protruding in the radial direction from the rotation shaft 23, and the anti-rotation portion 27 is inserted into at least the positioning hole 44.

  The cross-sectional shape perpendicular to the axial direction of the rotation shaft 23 of the rotation preventing portion 27 is a shape in which at least a part of the outer periphery thereof is disposed outside the outer periphery of the fixing portion 24 of the rotation shaft 23 and the rotation shaft 23 is It is preferably formed in a shape other than the center circle or a shape that fits in the circle. In addition, the cross-sectional shape of the rotation stopper 27 is preferably a shape in which one of the vertical width and the horizontal width is longer than the other. Examples of such a cross-sectional shape include a rectangle and a rounded rectangle.

  In addition, the rotation stopper 27 may be formed at least in a portion located inside the positioning hole 44, and may not be formed in a portion located inside the shaft hole 37 of the bracket 30.

  And the positioning hole 44 of the slide member 40 is formed in the shape which the rotation prevention part 27 fits and becomes a rotation stop, when the rotating shaft 23 of the pulley 20 rotates in the circumferential direction.

The shape of the positioning hole 44 is such that when the rotation shaft 23 is rotated when the rotation preventing portion 27 is also formed in a portion located inside the shaft hole 37 of the bracket 30, the rotation preventing portion 27 is A shape that fits before fitting with 37 is preferable. That is, at least a part of the positioning hole 44 is positioned on the inner side of the inner periphery of the shaft hole 37, and the rotation stopper 27 is fitted to that part. As the shape of the positioning hole 44, a shape that is one or more times larger than the cross-sectional shape perpendicular to the axial direction of the rotation stopper 27, or at least a part of the inner periphery of the positioning hole 44 protrudes toward the rotation stopper 27. The shape can be exemplified.

  FIG. 5 illustrates a state in which the rotating shaft 23 of the pulley 20 rotates in the circumferential direction. Hereinafter, based on FIG. 5, the operation of preventing the rotation of the rotary shaft 23 of the tension adjusting device 16 will be described.

  The rotation shaft 23 of the pulley 20 tries to rotate in the circumferential direction when the pulley 20 rotates, and at the same time, the rotation preventing portion 27 formed on the rotation shaft 23 also tries to rotate in the circumferential direction. In particular, the rotation of the rotary shaft 23 becomes significant when the fixing nut 50 is tightened.

  At this time, the outer peripheral surface of the rotation stopper 27 and the inner peripheral surface of the positioning hole 44 of the slide member 40 come into contact with each other and are fitted together. The rotation of the rotating shaft 23 is stopped by the fitting of the rotation stopper 27 and the positioning hole 44.

  As described above, the positioning hole 44 formed in the slide member 40 made of a material harder than the bracket 30 is engaged with the rotation preventing portion 27 when the rotation shaft 23 of the pulley 20 rotates in the circumferential direction. By being formed in a shape that prevents rotation, interference between the shaft hole 37 of the bracket 30 and the rotation stopper 27 can be avoided.

  As a result, even if the bracket 30 is made of a metal having a small specific gravity to reduce the weight of the device, the role of the rotation prevention of the pulley 20 with respect to the rotation shaft 23 is transferred from the shaft hole 37 of the bracket 30 to the positioning hole 44 of the slide member 40 Therefore, damage to the shaft hole 37 of the bracket 30 due to the rotation prevention of the rotating shaft 23 of the pulley 20 can be prevented, so that a decrease in durability due to weight reduction can be suppressed.

  Further, since the bracket 30 is made of a metal having a small specific gravity and the engine 10 can be reduced in weight, it is advantageous for improving fuel consumption.

  6 illustrates a state where the fixing nut 50 and the slide member 40 are omitted, and FIG. 7 illustrates a state where only the fixing nut 50 is omitted. Hereinafter, the tension adjusting device 16 will be described in more detail with reference to FIGS. 6 and 7.

  The cross-sectional shape perpendicular to the axial direction of the rotation shaft 23 of the rotation preventing portion 27 is composed of two equal-length parallel lines and two semicircles, and is a rounded rectangle with two semicircles facing each other in the longitudinal direction. The longitudinal direction is formed toward the longitudinal direction of the shaft hole 37 of the bracket 30. Accordingly, the anti-rotation portion 27 has outer peripheral planes that are parallel to each other and face each other in a direction orthogonal to the longitudinal direction. The anti-rotation portion 27 has a longitudinal dimension L2 and a width dimension B2. The shape of the shaft hole 37 is a long hole, and the longitudinal dimension is L3 and the width dimension is B3. The shape of the positioning hole 44 is a long hole, and has mutually parallel inner peripheral surfaces that face each other in a direction orthogonal to the longitudinal direction. The positioning hole 44 has a longitudinal dimension L4 and a width dimension L4.

  In the tension adjusting device 16 described above, the positioning hole 44 is formed as an elongated hole, and the longitudinal dimension L4 of the elongated hole is the axial hole 37 in a state where the longitudinal direction of the elongated hole faces the longitudinal direction of the axial hole 37. It is shorter than the longitudinal dimension L3 and its width dimension B4 is shorter than the width dimension B3 of the shaft hole 37. Further, the positioning hole 44 is formed such that the longitudinal dimension L4 is longer than the longitudinal dimension L2 of the rotation preventing part 27 and the width dimension B4 is longer than the width dimension B2 of the rotation preventing part 27.

  When the positioning hole 44 is formed in this way, the length between the anti-rotation portion 27 and the positioning hole 44 shown in FIG. 7 is longer than the length between the anti-rotation portion 27 and the shaft hole 37 shown in FIG. Becomes shorter. Thereby, when the rotating shaft 23 is about to rotate in the circumferential direction, the rotation preventing portion 27 is fitted to the positioning hole 44 before the shaft hole 37 to prevent rotation, so that the rotation shaft 23 is prevented from rotating. It is possible to avoid breakage of the shaft hole 37 due to the above, which is advantageous in improving durability.

  FIG. 8 is an enlarged view of the rotation stopper 27 and the positioning hole 44 of FIG. As described above, in the tension adjusting device 16, the positioning hole 44 is formed with the inner peripheral plane 44 a facing the direction perpendicular to the longitudinal direction of the shaft hole 37, and the rotation shaft 23 is connected to the rotation shaft 23. It is desirable to form a plurality of contact portions 28 that contact each of the inner peripheral planes 44a when rotated in the direction.

  The positioning hole 44 is a long hole, and is formed with an inner peripheral plane 44a facing in the direction orthogonal to the longitudinal direction of the shaft hole 37 and an inner peripheral cylindrical surface 44b facing the longitudinal direction. The inner peripheral planes 44a are planes parallel to each other.

  As described above, the anti-rotation portion 27 has a rounded rectangular shape, and is formed with an outer peripheral plane 27a facing in a direction perpendicular to the longitudinal direction of the shaft hole 37 and an outer peripheral cylindrical surface 27b facing in the longitudinal direction. The The outer peripheral plane 27a is a plane parallel to each other. Then, four contact portions 28 are formed at the boundary between the outer peripheral flat surface 27a and the outer peripheral cylindrical surface 27b. This contact part 28 is not limited to the corner | angular of the outer peripheral plane 27a and the outer peripheral cylinder surface 27b, For example, you may make a part of outer peripheral plane 27a protrude toward the inner peripheral plane 44a.

  With this configuration, when the rotary shaft 23 is about to rotate, the contact portions 28 formed on the rotation stoppers 27 come into contact with the respective inner peripheral planes 44a facing the positioning holes 44, and the rotation stoppers 27 and the positioning hole 44 are fitted. Further, when the rotating shaft 23 tries to rotate in the opposite direction, another contact portion 28 contacts each of the inner peripheral planes 44a.

  Thus, when the rotating shaft 23 is about to rotate, the rotation preventing portion 27 and the positioning hole 44 come into contact with each other at a plurality of locations, thereby reliably preventing the rotating shaft 23 from rotating. Moreover, since it is not necessary to make the rotation stopper part 27 and the positioning hole 44 into complicated shapes, it is advantageous for simplification of the manufacturing process.

  In the tension adjusting device 16 described above, when the collar 51 is provided, the collar 51 is preferably configured by rounding the corner portion 53 located on the bracket 30 side. As described above, when the corner portion 53 of the collar 51 is rounded, when a force for inclining the rotation shaft 23 is applied due to a change in tension of the endless belt 14 of the collar 51, the collar 51 is transmitted to the bracket 30. It is possible to avoid concentrating the power to one point. Thereby, durability of the bracket 30 can be improved. The same effect can be obtained by holding the washer 52 between the collar 51 and the bracket 30.

14 Belt 16 Tension adjusting device 20 Pulley 23 Rotating shaft 27 Non-rotating portion 30 Bracket 37 Shaft hole 40 Slide member 44 Positioning hole

Claims (4)

A pulley that has a rotating shaft and rotates in contact with an endless object or cord-like object, a bracket that has a shaft hole formed in an elongated hole, and a movement that can move in the longitudinal direction of the shaft hole, and that has a positioning hole And the slide member is laminated and fixed to the bracket so that the opening of the positioning hole overlaps a part of the opening of the shaft hole, and the rotation shaft includes the shaft hole and In the tension adjusting device configured to be able to adjust the position of the rotating shaft of the pulley in the longitudinal direction of the shaft hole by being fixed to the bracket and the slide member in a state of being inserted into both of the positioning holes,
The slide member is made of a material harder than the bracket;
A detent portion protruding in the radial direction from the rotating shaft of the pulley is inserted through at least the positioning hole,
2. The tension adjusting device according to claim 1, wherein the positioning hole is formed in a shape in which the rotation preventing portion is fitted to prevent rotation when the rotation shaft rotates in the circumferential direction.   The positioning hole is formed as a long hole, and the longitudinal dimension of the elongated hole is shorter than the longitudinal dimension of the axial hole, with the longitudinal direction of the elongated hole facing the longitudinal direction of the axial hole, and The tension adjusting device according to claim 1, wherein the width dimension is shorter than the width dimension of the shaft hole. The positioning hole has an inner peripheral plane facing the direction perpendicular to the longitudinal direction of the shaft hole;
3. The tension adjusting device according to claim 1, wherein the rotation preventing portion includes a plurality of contact portions that come into contact with each of the inner peripheral planes when the rotation shaft rotates in the circumferential direction thereof.   The tension adjustment according to any one of claims 1 to 3, wherein the bracket is fixed to the engine or the periphery of the engine, and the pulley contacts an endless belt or chain connected to a crankshaft of the engine. apparatus.