JP2011231891A - Power transmission mechanism, and belt attaching method for power transmission mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission mechanism in which a transmission belt can be attached without using a jig for exclusive use, and which can prevent occurrence of dislocation or displacement or the like of the transmission belt.SOLUTION: The power transmission mechanism 10 includes: a crank pulley 12 integrally provided with one end side of a crankshaft 11 of an engine for rotation; a water pump pulley 22 integrally provided with one end side of a rotary shaft 21 of a water pump; and a transmission belt 31 bridged between the crank pulley 12 and the water pump pulley 22. A projection 24 for hanging the transmission belt 31 when the transmission belt 31 is assembled between the pulleys 12 and 22 is protruded towards the front side of a front surface 25 of the water pump pulley 22, and the projection 24 is disposed concentrically with the water pump pulley 22.

Description

  The present invention relates to a power transmission mechanism including a plurality of pulleys and a transmission belt stretched between the pulleys. The present invention also relates to a belt assembling method for assembling a transmission belt between pulleys of such a power transmission mechanism.

  An engine (internal combustion engine) mounted on a vehicle or the like is generally equipped with various auxiliary machines such as a water pump, an alternator, a power steering pump, and an air conditioner compressor. These auxiliary machines are driven by an engine output transmitted by a power transmission mechanism. The power transmission mechanism includes a crank pulley attached to the crankshaft of the engine, an auxiliary pulley attached to each auxiliary machine, and a transmission belt that is stretched between these pulleys.

  In such a power transmission mechanism, for example, a V pulley and a V-ribbed belt are used as the pulley and the transmission belt in order to prevent the transmission belt from sliding off the pulley. Moreover, since it is necessary to maintain the tension of the transmission belt constant, an auto tensioner is used. In a power transmission mechanism equipped with an auto tensioner, when the transmission belt is assembled between pulleys, for example, with the auto tensioner being free with a general tool, the crank pulley, the auxiliary pulley, the tensioner pulley of the auto tensioner (idler pulley) ), Etc., and then adjust the auto tensioner to apply a certain tension to the transmission belt.

  A power transmission mechanism that does not include an auto tensioner is also known. In this case, a low elastic belt (so-called stretch belt) is used as the transmission belt, and the tension is maintained by the elastic force (stretching force) of the transmission belt itself. However, in a power transmission mechanism using a low-elasticity belt as a transmission belt, an auto tensioner is not necessary, but when assembling the transmission belt between pulleys, it is necessary to wind the pulley while stretching the transmission belt. For this reason, a dedicated jig (special tool) for assembling the transmission belt between the pulleys is required, and the assembly work of the transmission belt cannot be performed only with a general tool (for example, a ratchet handle, an eyeglass wrench, etc.). There's a problem.

  Conventionally, there has been proposed a power transmission mechanism that enables the assembly work of a transmission belt to be performed without using a dedicated jig (see, for example, Patent Document 1). This Patent Document 1 shows that a notch for guiding a transmission belt is provided on a flange of a pulley, and when the transmission belt is assembled between pulleys, the notch is used to hang the transmission belt between the pulleys. Yes. However, when the engine is in operation, there is a possibility that the transmission belt will skip or the belt may come off from the notch. Further, if there is a deviation (misalignment) in the alignment between the pulleys, there is a possibility that the transmission belt may be rubbed and damaged by the notch during engine operation.

JP 2005-195041 A

  The present invention has been made in consideration of the technical problems as described above. A transmission belt can be assembled without using a dedicated jig to prevent the transmission belt from jumping or coming off the belt. It is an object to provide a possible power transmission mechanism and a belt assembling method in such a power transmission mechanism.

  In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention is a power transmission mechanism provided with a plurality of pulleys and a transmission belt spanned between these pulleys, and among the plurality of pulleys, on one axial surface side of one pulley, A protrusion for hooking the transmission belt when the transmission belt is assembled between the pulleys is provided so as to protrude toward one side in the axial direction, and the protrusion is disposed concentrically with the one pulley. It is said.

  Here, the assembly | attachment operation | work between the pulleys of a transmission belt using a protrusion is demonstrated. First, set the transmission belt between the pulleys. At this time, the transmission belt is wound around a pulley (other pulley) other than the one pulley among the plurality of pulleys, and the transmission belt is hooked on the outer peripheral surface of the protrusion while being wound around the one pulley.

  In this case, the transmission belt is placed on the flange of the one pulley at a position upstream of the central position of the region where the transmission belt of the one pulley can be wound, in the pulley rotation direction (rotation direction during assembly work). Let's get on. Then, the transmission belt riding on the flange is hooked on the outer peripheral surface of the protrusion on the inner diameter side of the flange.

  Next, while holding (depressing) the transmission belt so as to secure the length of the transmission belt wound around the one pulley, one of the plurality of pulleys is used, for example, using a ratchet handle or the like. Rotate. At this time, one hand may be used to hold the transmission belt and the other hand to operate a ratchet handle or the like to rotate one of the pulleys. As a result, the transmission belt is gradually extended with the rotation of the one pulley, the winding length of the transmission belt around the one pulley is gradually increased, and eventually the transmission belt is completely attached to the one pulley. Wrapped around.

  According to the said structure, a transmission belt can be easily assembled | attached between pulleys using the protrusion provided in said one pulley. Thereby, the assembly work of a transmission belt can be performed only with a general tool (for example, ratchet handle, eyeglass wrench, etc.) without using a dedicated jig (special tool).

  Specifically, the protrusion plays a role of reducing the pressing force to the transmission belt necessary for securing the length of the transmission belt wound around the one pulley, and the transmission belt acting on the protrusion The necessary pressing force on the transmission belt is reduced by the amount of tension. In this way, since the pressing force on the transmission belt necessary for securing the length of the transmission belt wound around the one pulley by the protrusion is small, the transmission belt can be easily assembled between the pulleys. .

  In addition, unlike the conventional configuration described above (a configuration in which a notch is provided in the flange), it is possible to prevent the transmission belt from skipping or from being detached when the engine is operating. In other words, the transmission belt can be assembled between the pulleys without providing a notch or other irregularities on the flange of the one pulley, so that the transmission belt can be prevented from jumping or detaching when the engine is operating. Can be prevented. Even if there is misalignment between the pulleys, it is possible to prevent damage to the transmission belt due to unevenness such as notches during engine operation. Further, since the projection can be formed by casting or pressing, the projection can be easily provided on the one pulley, and the cost can be reduced as compared with the case where the notch is formed on the flange of the one pulley. Can do.

  In the power transmission mechanism of the present invention, it is preferable that the protrusion is formed to have a smaller diameter as the tension of the transmission belt increases.

  When a low elastic belt (stretch belt) is used as the transmission belt, the tension required in the power transmission mechanism is managed by changing the length of the transmission belt. When the tension required in the power transmission mechanism is low, a long transmission belt is used. In this case, when the transmission belt is assembled between the pulleys, the slackness of the transmission belt can be suppressed by increasing the diameter of the protrusion.

  Conversely, when the tension required in the power transmission mechanism is high, a transmission belt having a short length is used. In this case, when the transmission belt is assembled between the pulleys, the length of the transmission belt wound around the one pulley when the transmission belt is set between the pulleys can be ensured as large as possible by making the protrusions have a small diameter. it can.

  In the power transmission mechanism of the present invention, a flange that protrudes to the outer diameter side of the pulley groove into which the transmission belt is fitted is provided on one axial side of the one pulley, and the outer side of the flange on one side in the axial direction is provided. It is preferable that the periphery has an R shape.

  When the transmission belt is assembled between the pulleys, the transmission belt rides over the flange on one axial side of the one pulley just before the transmission belt is assembled to the one pulley. In this configuration, since the outer peripheral edge on one side in the axial direction of the flange has an R shape, the transmission belt smoothly moves over the flange and is assembled to the one pulley. Thereby, damage to the transmission belt and the like can be prevented. Further, in this configuration, compared to a case where the outer peripheral edge of the flange is not formed in an R shape, the movement path when the transmission belt rides over the flange is shortened, so that the transmission belt can be prevented from being excessively extended. Thereby, the operation load at the time of rotating any pulley among several pulleys can be reduced, and the assembly | attachment operation | work of a transmission belt can be performed easily.

  In the power transmission mechanism of the present invention, the transmission belt is a V-ribbed belt having a plurality of ribs extending in the belt length direction, and a radius of curvature of the outer peripheral edge is larger than an interval between adjacent ribs of the transmission belt. It is preferable that it is set.

  According to this configuration, when the transmission belt rides over the flange of the one pulley, the outer peripheral edge of the flange of the one pulley can be prevented from entering between adjacent ribs of the transmission belt. It is possible to reliably avoid defects in the ribs.

  In the power transmission mechanism of the present invention, the one pulley is preferably a crank pulley attached to one end of a crankshaft of the engine.

  In the case of a crank pulley, since the flange width (axial width) is larger than that of an auxiliary pulley such as a water pump pulley, the radius of curvature of the outer peripheral edge of the flange can be made as large as possible. Thereby, the extension of the transmission belt when the transmission belt rides over the flange of the crank pulley can be reduced, and the operation load when rotating any one of the plurality of pulleys can be reduced.

  The present invention also relates to a belt assembling method for assembling a transmission belt between a plurality of pulleys in a power transmission mechanism including a plurality of pulleys and a transmission belt spanned between the pulleys. A protrusion projecting toward one axial direction is disposed on one axial surface of one pulley in a concentric manner with the one pulley, and the transmission belt is connected to the one pulley among the plurality of pulleys. Wrap it around other pulleys and hook the transmission belt around the one pulley while hooking it on the outer surface of the projection, and hold down the transmission belt so as to secure the length of the transmission belt around the one pulley. However, one of the plurality of pulleys is rotated.

  According to the above method, the transmission belt can be easily assembled between the pulleys by using the protrusion provided on the one pulley. Thereby, the assembly work of a transmission belt can be performed only with a general tool (for example, ratchet handle, eyeglass wrench, etc.) without using a dedicated jig (special tool).

  In this case, a flange is provided on one side in the axial direction of the one pulley so as to protrude to the outer diameter side of a pulley groove into which the transmission belt is fitted. At the position upstream of the central position of the area where the pulley belt can be wound around the pulley in the direction of pulley rotation, the belt is mounted on the flange, and the belt mounted on the flange has an inner diameter larger than the flange. It is preferable to hook on the outer peripheral surface of the projection on the side. In addition, when rotating any one of the plurality of pulleys, it is preferable to hold down a portion that rides on the flange of the transmission belt. In this way, by pressing the portion of the transmission belt that rides on the flange, a frictional force can be effectively generated between the transmission belt and the one pulley even if the pressing force on the transmission belt is small. it can. As a result, since the pressing force on the transmission belt necessary for securing the length of the transmission belt wound on the one pulley is small, the transmission belt can be easily assembled between the pulleys.

  According to the present invention, a transmission belt can be easily assembled between pulleys by using a projection provided on one pulley among a plurality of pulleys. Thereby, the assembly work of a transmission belt can be performed only with a general tool, without using a dedicated jig.

It is a front view showing typically a schematic structure of a power transmission mechanism concerning an embodiment of the present invention. It is the X1-X1 sectional view taken on the line of FIG. It is a front view which shows typically the procedure 1 of the assembly | attachment operation | work of the transmission belt in the power transmission mechanism of FIG. It is the figure which looked at the water pump pulley and transmission belt of the power transmission mechanism of FIG. 3 from the Y1 direction. It is a front view which shows typically the procedure 2 of the assembly | attachment operation | work of the transmission belt in the power transmission mechanism of FIG. It is a front view which shows typically the procedure 3 of the assembly | attachment operation | work of the transmission belt in the power transmission mechanism of FIG. It is a figure corresponding to FIG. 1 of the power transmission mechanism which concerns on other Embodiment 1. FIG. It is a figure corresponding to FIG. 3 which shows the assembly | attachment operation | work 1 of the transmission belt in the power transmission mechanism of FIG. It is a figure corresponding to FIG. 5 which shows the assembly | attachment operation | work 2 of the transmission belt in the power transmission mechanism of FIG. It is a figure corresponding to FIG. 6 which shows the assembly | attachment operation | work 3 of the transmission belt in the power transmission mechanism of FIG. It is sectional drawing which shows typically the modification of the flange of the crank pulley of the power transmission mechanism of FIG.

  Embodiments of the present invention will be described with reference to the accompanying drawings.

  In this embodiment, a power transmission mechanism that transmits the rotational driving force of a crankshaft, which is an output shaft of an engine (internal combustion engine) mounted on a vehicle or the like, to a rotating shaft of a water pump as an auxiliary device will be described as an example. To do.

  As shown in FIGS. 1 and 2, the power transmission mechanism 10 includes a crank pulley 12 that is attached to one end side (front end side) of the crankshaft 11 of the engine, and one end side (front end) of the rotary shaft 21 of the water pump. A water pump pulley 22 that is integrally attached to the rotation side, and a transmission belt 31 that is stretched between the crank pulley 12 and the water pump pulley 22. The power transmission mechanism 10 is configured such that the rotational driving force of the crankshaft 11 accompanying the driving of the engine is transmitted from the crank pulley 12 to the water pump pulley 22 via the transmission belt 31 to drive the water pump. Yes.

  Next, each part of the power transmission mechanism 10 will be described with reference to FIGS. 1 and 2.

  The crank pulley 12 is provided on the front side of the engine, and is fastened to the front end portion of the crankshaft 11 of the engine using a set bolt 13. The crankshaft 11 is disposed below the rotating shaft 21 of the water pump. A pulley groove 12 a into which the rib 31 a of the transmission belt 31 is fitted is formed on the outer peripheral surface of the crank pulley 12. The pulley groove 12a is composed of a plurality of V-shaped grooves extending in the circumferential direction. On both sides in the axial direction of the pulley groove 12a, flanges (protruding portions) 12b that protrude to the outer diameter side of the pulley groove 12a are provided.

  The water pump pulley 22 is provided on the front side of the engine, and is arranged at a predetermined interval from the crank pulley 12. The water pump pulley 22 is fixed to a pulley seat 23 attached to the front end portion of the rotary shaft 21 of the water pump. A pulley groove 22 a into which the rib 31 a of the transmission belt 31 is fitted is formed on the outer peripheral surface of the water pump pulley 22. The pulley groove 22a is composed of a plurality of V-shaped grooves extending in the circumferential direction. On both sides in the axial direction of the pulley groove 22a, flanges (protruding portions) 22b that protrude outward from the pulley groove 22a are provided.

  A cylindrical projection 24 is integrally provided on the water pump pulley 22. The protrusion 24 is provided for hooking the transmission belt 31 when the transmission belt 31 is assembled. The protrusion 24 is formed on the front surface 25 of the water pump pulley 22 so as to protrude forward. The outer diameter of the protrusion 24 is smaller than the outer diameter of the water pump pulley 22 and is arranged concentrically with the water pump pulley 22. The protrusion amount of the protrusion 24 with respect to the front surface 25 is set to be substantially the same as the axial width of the transmission belt 31. The protrusion amount of the protrusion 24 with respect to the front surface 25 is not particularly limited as long as the transmission belt 31 can be hooked on the outer peripheral surface 24a of the protrusion 24 when the transmission belt 31 is assembled.

  The protrusion 24 can be formed by casting or pressing. When the protrusion 24 is formed by casting, the protrusion 24 can be formed integrally with the water pump pulley 22 by providing a recess having a shape corresponding to the shape of the protrusion 24 in the mold. Note that the protrusions 24 formed by casting or pressing can be used as they are, but the protrusions 24 may be subjected to post-processing such as lathe processing.

  The transmission belt 31 is a low elastic belt (stretch belt). In this embodiment, a V-ribbed belt having a plurality of V-shaped ribs 31 a extending in the longitudinal direction (belt length direction) is used as the transmission belt 31. As already described, when a low elastic belt is used as the transmission belt 31, the tension is maintained by the elastic force (stretching force) of the transmission belt 31 itself. For this reason, an auto tensioner is unnecessary.

  Next, the procedure of the assembling work for assembling the transmission belt 31 between the pulleys 12 and 22 in the power transmission mechanism 10 will be described with reference to FIGS.

  First, the operator sets the transmission belt 31 between the pulleys 12 and 22 as shown in FIGS. Specifically, the operator wraps the transmission belt 31 around the crank pulley 12 and hooks the transmission belt 31 on the outer peripheral surface 24 a of the protrusion 24 while wrapping the transmission belt 31 around the water pump pulley 22.

  At this time, the transmission belt 31 is disposed between the pulleys 12 and 22 in a state where the transmission belt 31 is not slack and is not stretched (a state where no tension is applied). Specifically, the transmission belt 31 is wound around the entire area where the crank pulley 12 can be wound, and the winding length of the transmission belt 31 around the crank pulley 12 is maximum. On the other hand, with respect to the water pump pulley 22, the transmission belt 31 is wound only on a part of the wrappable region, and the transmission belt 31 is wound around the remaining region. In order to hang, it is necessary to extend the transmission belt 31. That is, while the transmission belt 31 is extended, the winding length of the transmission belt 31 around the water pump pulley 22 (the length of the portion of the transmission belt 31 wound around the water pump pulley 22) C1 is gradually increased. There is a need.

  In this embodiment, a projection 24 having a smaller diameter than the water pump pulley 22 is provided, and the transmission belt 31 is hooked on the outer peripheral surface 24a of the projection 24 when the transmission belt 31 is assembled. As shown in FIGS. 3 and 4, the transmission belt 31 on the pulley groove 22 a of the water pump pulley 22 is bent and the direction thereof is changed obliquely forward so that the transmission belt 31 is hooked on the outer peripheral surface 24 a of the protrusion 24. .

  In this case, the transmission belt is located at a position upstream of the central position A0 of the area where the transmission belt 31 of the water pump pulley 22 can be wound (position A1 in FIG. 3) in the pulley rotation direction (rotation direction during assembly work). 31 is mounted on the flange 22b of the water pump pulley 22. The transmission belt 31 riding on the flange 22b is hooked on the outer peripheral surface 24a of the protrusion 24 on the inner diameter side of the flange 22b.

  The operator presses (presses) the transmission belt 31 so that the transmission belt 31 caught on the flange 22b does not deviate from the position A1. In this case, what is necessary is just to hold | suppress the part 31b which rides on the flange 22b of the transmission belt 31 (it is hooked). The position A1 is a position where the transmission belt 31 is hooked on the flange 22b when the transmission belt 31 is set between the pulleys 12 and 22 in a state where the transmission belt 31 is not slack and is not stretched. The position A <b> 1 is a position in the rotation direction of the water pump pulley 22, and moves with the rotation of the water pump pulley 22. On the other hand, the central position A0 is a position on the straight line L1 connecting the centers of the pulleys 12 and 22, and does not move even when the water pump pulley 22 rotates.

  Next, as shown in FIG. 5, the operator clutches the set bolt 13 of the crank pulley 12 with the ratchet handle 40 while pressing the portion 31 b that rides (hangs) on the flange 22 b of the transmission belt 31. Turn the pulley 12. In this case, the operator may press the transmission belt 31 with one hand and operate the ratchet handle 40 with the other hand to rotate the crank pulley 12. Then, the water pump pulley 22 also rotates in the same direction due to the frictional force between the transmission belt 31 and the water pump pulley 22, and the position A <b> 1 moves as the water pump pulley 22 rotates. In this case, the crank pulley 12 is rotated in the direction in which the winding length C1 of the transmission belt 31 around the water pump pulley 22 is increased. Here, the crank pulley 12 is rotated in a direction in which the position A1 approaches the central position A0 (clockwise in FIG. 5).

  During the rotation of the water pump pulley 22, the operator moves one hand holding the transmission belt 31 following the movement of the position A1. That is, while holding the portion 31b hooked to the flange 22b of the transmission belt 31 with one hand so as to secure the winding length C1 of the transmission belt 31 around the water pump pulley 22, the one hand is held at the position A1. Move following the movement of. In this case, even if the water pump pulley 22 rotates, the transmission belt 31 is pressed so that the transmission belt 31 does not slip with respect to the water pump pulley 22. In other words, the transmission belt 31 is pressed so as to maintain the state where the transmission belt 31 is hooked on the flange 22b at the position A1, and a frictional force between the transmission belt 31 and the water pump pulley 22 is applied.

  As a result, the transmission belt 31 is gradually extended with the rotation of the water pump pulley 22, and the winding length C1 of the transmission belt 31 around the water pump pulley 22 is gradually increased. Specifically, when the position A1 that is the pressing position of the transmission belt 31 approaches the center position A0 by the rotation of the water pump pulley 22, the winding length C1 of the transmission belt 31 around the water pump pulley 22 gradually increases. Become bigger. On the other hand, as the water pump pulley 22 rotates, the length of the transmission belt 31 caught on the outer peripheral surface 24a of the protrusion 24 gradually decreases. In this way, the length C1 of the transmission belt 31 wound around the large-diameter water pump pulley 22 is increased, while the length of the transmission belt 31 caught on the outer peripheral surface 24a of the small-diameter protrusion 24 is decreased. The belt 31 is gradually extended as the water pump pulley 22 rotates.

  Then, the operator rotates the crank pulley 12 clockwise, for example, rotates the water pump pulley 22 to the position shown in FIG. 6, then separates one hand from the transmission belt 31, and the transmission belt 31 at the position A <b> 1. Release the pressure. If the position A1 has passed the center position A0, the transmission belt 31 is not likely to come off the water pump pulley 22 even if one hand is released, so the pressure on the transmission belt 31 is released. The position may be anywhere as long as it is a position downstream of the central position A0 in the pulley rotation direction.

  After the state shown in FIG. 6, the operator further rotates the crank pulley 12 clockwise and rotates the water pump pulley 22. Thereby, the winding length C1 of the transmission belt 31 around the water pump pulley 22 further increases from the state shown in FIG. 6, and eventually the transmission belt 31 is completely wound around the water pump pulley 22. At this time, the portion of the transmission belt 31 that is not wound around the water pump pulley 22 gradually approaches the flange 22b as the water pump pulley 22 rotates, and finally the portion 31c slides on the flange 22b. In this way, it gets over and is assembled to the water pump pulley 22. Thereafter, the ratchet handle 40 is removed from the crank pulley 12 to complete the belt assembling operation.

  As described above, according to this embodiment, the transmission belt 31 can be easily assembled between the pulleys 12 and 22 by using the protrusions 24 provided on the water pump pulley 22. Thereby, the assembly | attachment operation | work of the transmission belt 31 can be performed only with general tools like the ratchet handle 40, without using an exclusive jig | tool (special tool).

  Here, if the protrusion 24 is not provided in the water pump pulley 22, the pressing force to the transmission belt 31 required in order to ensure the winding length C1 of the transmission belt 31 to the water pump pulley 22 will become large. . That is, there is a possibility that the transmission belt 31 is detached from the water pump pulley 22 or the transmission belt 31 slips relative to the water pump pulley 22 due to the tension that increases as the transmission belt 31 extends. For this reason, in order to secure the winding length C1 of the transmission belt 31 around the water pump pulley 22, the pressing force on the transmission belt 31 is increased, and the frictional force corresponding to the tension of the transmission belt 31 is transmitted. It must be generated between the belt 31 and the water pump pulley 22.

  On the other hand, in this embodiment, since the transmission belt 31 is hooked on the outer peripheral surface 24a of the protrusion 24 provided on the water pump pulley 22, the winding length C1 of the transmission belt 31 around the water pump pulley 22 is ensured. Therefore, the pressing force to the transmission belt 31 necessary for this is reduced. The protrusion 24 plays a role of reducing the pressing force to the transmission belt 31, and the pressing force to the transmission belt 31 is reduced by the amount of tension of the transmission belt 31 that acts on the protrusion 24. Further, since the portion 31b hooked on the flange 22b of the transmission belt 31 is pressed, even if the pressing force to the transmission belt 31 is small, a frictional force is effectively generated between the transmission belt 31 and the water pump pulley 22. be able to. Thus, since the pressing force to the transmission belt 31 necessary for securing the winding length C1 of the transmission belt 31 around the water pump pulley 22 is small, the transmission belt 31 can be easily placed between the pulleys 12 and 22. Can be assembled. In addition, since the pressing force to the transmission belt 31 is small, replacement work of the transmission belt 31 in a limited space such as in the engine room can be easily performed.

  In addition, in this embodiment, unlike the above-described conventional configuration (configuration in which a notch portion is provided in the flange), it is possible to prevent the transmission belt 31 from skipping or the belt from coming off during engine operation. That is, since the flange 22b of the water pump pulley 22 is not provided with irregularities such as notches, it is possible to prevent the transmission belt 31 from skipping or the belt from coming off during engine operation. Further, even if there is a misalignment between the pulleys 12 and 22, it is possible to prevent damage to the transmission belt 31 due to irregularities such as notches during engine operation.

  Further, as described above, since the protrusion 24 can be formed on the water pump pulley 22 by casting or pressing, the water pump pulley 22 is compared with a case where the flange 22b of the water pump pulley 22 is notched. The protrusion 24 can be easily provided on the substrate, and the cost can be reduced.

  After setting the transmission belt 31 between the pulleys 12 and 22, the ratchet handle 40 is attached to the crank pulley 12. After the ratchet handle 40 is attached to the crank pulley 12, the transmission belt is set between the pulleys 12 and 22. May be.

  Here, the outer diameter of the protrusion 24 is preferably set according to the length (circumferential length) of the transmission belt 31. Specifically, the outer diameter of the protrusion 24 may be set larger as the length of the transmission belt 31 is longer. This point will be described.

  When a low elastic belt (stretch belt) is used as the transmission belt 31, the tension required in the power transmission mechanism 10 is managed by changing the length of the transmission belt 31. When the tension required in the power transmission mechanism 10 is low, the transmission belt 31 having a long length is used. In this case, by increasing the outer diameter of the protrusion 24, when the transmission belt 31 is assembled between the pulleys 12 and 22, the slack of the portion of the transmission belt 31 disposed between the crank pulley 12 and the protrusion 24 can be suppressed. it can.

  Conversely, when the tension required in the power transmission mechanism 10 is high, the transmission belt 31 having a short length is used. In this case, by reducing the outer diameter of the protrusion 24, when the transmission belt 31 is assembled between the pulleys 12 and 22, the transmission belt 31 to the water pump pulley 22 when the transmission belt 31 is set between the pulleys 12 and 22. Can be secured as large as possible.

-Other embodiments-
The present invention is not limited only to the above-described embodiments, and all modifications and applications within the scope of the claims and within the scope equivalent to the scope are possible.

  The shape of the protrusion 24 described above is an example, and the shape of the protrusion 24 may be formed in other shapes (for example, a cylindrical shape).

  The above-described attachment of the water pump pulley 22 to the rotating shaft 21 using the pulley sheet 23 is an example, and the water pump pulley 22 may be attached to the rotating shaft 21 by other means without using the pulley sheet 23.

  Moreover, in the said embodiment, although the protrusion 24 was provided in the water pump pulley 22, you may replace with this structure and may provide the protrusion 14 in the crank pulley 12 as shown in FIG. The power transmission mechanism 100 shown in FIG. 7 will be described. The power transmission mechanism 100 is different from the above-described embodiment in that the protrusion 14 is disposed and the assembly work of the transmission belt 31 using the protrusion 14 is different from the above-described embodiment. This is substantially the same as the transmission mechanism 10.

  As shown in FIG. 7, the crank pulley 12 is integrally provided with a cylindrical protrusion 14. The protrusion 14 is provided for hooking the transmission belt 31 when the transmission belt 31 is assembled. The protrusion 14 is formed on the front surface 15 of the crank pulley 12 so as to protrude forward. The outer diameter of the protrusion 14 is smaller than the outer diameter of the crank pump pulley 12 and is arranged concentrically with the crank pulley 12. The protrusion amount of the protrusion 14 with respect to the front surface 15 is set to be substantially the same as the axial width of the transmission belt 31.

  Next, the procedure of the assembling work for assembling the transmission belt 31 between the pulleys 12 and 22 in the power transmission mechanism 100 will be described with reference to FIGS. Detailed description of the same procedure as in the above embodiment will be omitted.

  First, the worker sets the transmission belt 31 between the pulleys 12 and 22 as shown in FIG. Specifically, the operator wraps the transmission belt 31 around the crank pulley 12 and hooks the transmission belt 31 on the outer peripheral surface 14 a of the protrusion 14 while wrapping the transmission belt 31 around the crank pulley 12. At this time, the transmission belt 31 is disposed between the pulleys 12 and 22 in a state where the transmission belt 31 is not slack and is not stretched (a state where no tension is applied).

  Then, the transmission belt 31 on the pulley groove 12 a of the crank pulley 12 is bent and the direction thereof is changed obliquely forward, and the transmission belt 31 is hooked on the outer peripheral surface 14 a of the protrusion 14. In this case, the transmission belt 31 is located at a position upstream of the center position B0 of the region where the transmission belt 31 of the crank pulley 12 can be wound (position B1 in FIG. 8) in the pulley rotation direction (rotation direction during assembly work). Is mounted on the flange 12b of the crank pulley 12. The transmission belt 31 riding on the flange 12b is hooked on the outer peripheral surface 14a of the protrusion 14 on the inner diameter side of the flange 12b.

  The operator presses (presses) the transmission belt 31 so that the transmission belt 31 caught on the flange 12b does not deviate from the position B1. In this case, the portion 31d that rides on (hangs on) the flange 12b of the transmission belt 31 may be pressed. The position B1 is a position where the transmission belt 31 is caught by the flange 12b when the transmission belt 31 is set between the pulleys 12 and 22 in a state where the transmission belt 31 is not slack and is not extended. The position B1 is a position in the rotation direction of the crank pulley 12 and moves with the rotation of the crank pulley 12. On the other hand, the center position B0 is a position on a straight line L2 connecting the centers of the pulleys 12 and 22, and does not move even when the crank pulley 12 rotates.

  Next, as shown in FIG. 9, the operator clutches the set bolt 13 of the crank pulley 12 with the ratchet handle 40 and rotates the crank pulley 12 while pressing the portion 31 d caught on the flange 12 b of the transmission belt 31. . In this case, the operator may press the transmission belt 31 with one hand and operate the ratchet handle 40 with the other hand to rotate the crank pulley 12. Then, the water pump pulley 22 also rotates in the same direction by the frictional force between the transmission belt 31 and the water pump pulley 22. As the crank pulley 12 rotates, the position B1 moves. In this case, the crank pulley 12 is rotated in a direction in which the winding length C2 of the transmission belt 31 around the crank pulley 12 is increased. Here, the crank pulley 12 is rotated in a direction in which the position B1 approaches the center position B0 (clockwise in FIG. 9).

  During the rotation of the crank pulley 12, the operator moves one hand holding the transmission belt 31 following the movement of the position B1. That is, while holding the portion 31d hooked on the flange 12b of the transmission belt 31 with one hand so as to secure the winding length C2 of the transmission belt 31 around the crank pulley 12, one hand is held at the position B1. Move to follow the movement. In this case, even if the crank pulley 12 rotates, the transmission belt 31 is pressed so that the transmission belt 31 does not slip with respect to the crank pulley 12. In other words, the transmission belt 31 is pressed to apply the frictional force between the transmission belt 31 and the crank pulley 12 so as to maintain the state where the transmission belt 31 is hooked on the flange 12b at the position B1.

  As a result, the transmission belt 31 is gradually extended with the rotation of the crank pulley 12, and the length of the transmission belt 31 wound around the crank pulley 12 (the length of the portion of the transmission belt 31 wound around the crank pulley 12). C) C2 gradually increases. Specifically, when the position B1 that is the pressing position of the transmission belt 31 approaches the center position B0 by the rotation of the crank pulley 12, the winding length C2 of the transmission belt 31 around the crank pulley 12 gradually increases. Become. On the other hand, as the crank pulley 12 rotates, the length of the transmission belt 31 caught on the outer peripheral surface 14a of the protrusion 14 gradually decreases. As described above, the length C2 of the transmission belt 31 wound around the large-diameter crank pulley 12 is increased, while the length of the transmission belt 31 caught on the outer peripheral surface 14a of the small-diameter protrusion 14 is decreased. 31 is gradually extended as the crank pulley 12 rotates.

  Then, for example, after rotating the crank pulley 12 to the position shown in FIG. 10, the worker releases one hand from the transmission belt 31 and releases the pressure on the transmission belt 31 at the position B1. If the position B1 has passed the central position B0, the transmission belt 31 is not likely to come off the crank pulley 12 even if one hand is released, so the position where the pressure on the transmission belt 31 is released is released. May be anywhere as long as it is a position downstream of the central position B0 in the pulley rotation direction.

  After the state shown in FIG. 10, the operator further rotates the crank pulley 12 clockwise. Thereby, the winding length C2 of the transmission belt 31 around the crank pulley 12 further increases from the state shown in FIG. 10, and eventually the transmission belt 31 is completely wound around the crank pulley 12. At this time, the portion 31e of the transmission belt 31 that is not wound around the crank pulley 12 gradually approaches the flange 12b as the crank pulley 12 rotates, and eventually the portion 31e slides on the flange 12b. In this way, it gets over and is assembled to the crank pulley 12. Thereafter, the ratchet handle 40 is removed from the crank pulley 12 to complete the belt assembling operation.

  As described above, according to this embodiment, the same effect as in the above embodiment can be obtained. That is, the transmission belt 31 can be easily assembled between the pulleys 12 and 22 by using the protrusions 14 provided on the crank pulley 12. Thereby, the assembly work of the transmission belt 31 can be performed only with a general tool (for example, ratchet handle, eyeglass wrench, etc.) without using a dedicated jig. In this embodiment as well, it is preferable to set the outer diameter of the protrusion 14 to be larger as the length of the transmission belt 31 is longer.

  Here, as shown in FIG. 11, it is preferable to subject the outer peripheral edge 12c on the front side of the flange 12b on the front side (one axial side) of the crank pulley 12 to R processing. This modification will be described.

  As described above, when the transmission belt 31 is assembled between the pulleys 12 and 22, the transmission belt 31 slides on the flange 12 b on the front side of the crank pulley 12 just before the transmission belt 31 is assembled to the crank pulley 12. get over. However, at this time, if R is not attached to the outer peripheral edge 12c of the flange 12b, the rib 31a of the transmission belt 31 strongly rubs against the outer peripheral edge 12c of the flange 12b, so that the rib 31a may be damaged. In some cases, the rib 31a of the transmission belt 31 may be caught on the outer peripheral edge 12c of the flange 12b, and the rib 31a may be missing. Furthermore, since the transmission belt 31 is excessively stretched and excessive tension is generated, there is a problem that an operation load when the crank pulley 12 is rotated becomes high.

  On the other hand, in this embodiment, as shown in FIG. 11, the outer peripheral edge 12c on the front side of the flange 12b on the front side of the crank pulley 12 has an R shape. For this reason, when the transmission belt 31 is assembled between the pulleys 12 and 22, the transmission belt 31 smoothly passes over the flange 12 b on the front side of the crank pulley 12 and is assembled to the crank pulley 12. Thereby, damage to the rib 31a of the transmission belt 31, a chip | tip (mountain chip), etc. can be prevented. Here, the radius of curvature of the outer peripheral edge 12c of the flange 12b is preferably set to be larger than the interval W1 (for example, 2.5 mm) between the adjacent ribs 31a, 31a of the transmission belt 31. In this way, the outer peripheral edge 12c of the flange 12b can be prevented from entering between the adjacent ribs 31a, 31a of the transmission belt 31, and the loss of the rib 31a of the transmission belt 31 can be reliably avoided.

  Moreover, since the movement path | route at the time of the transmission belt 31 getting over on the flange 12b becomes short, it can avoid extending the transmission belt 31 excessively. Thereby, the operation load at the time of rotating the crank pulley 12 can be reduced, and the assembly work of the transmission belt 31 can be performed easily. Accordingly, it is possible to improve the reliability of the transmission belt 31 and improve the assembling property. In this case, the larger the radius of curvature of the outer peripheral edge 12c of the flange 12b, the more the extension of the transmission belt 31 can be reduced and the operation load when rotating the crank pulley 12 can be reduced. ) It is preferable to provide R by making maximum use of W2.

  Also in the above-described embodiment, it is preferable that the outer peripheral edge of the flange 22b of the water pump pulley 22 provided with the protrusions 24 has an R shape. In this case, since the width of the flange 22b of the water pump pulley 22 is smaller than the width W2 of the flange 12b of the crank pulley 12, the effect of reducing the extension of the transmission belt 31 described above and the rotation of the crank pulley 12 can be reduced. The effect of reducing the operation load is reduced. However, by setting the radius of curvature of the outer peripheral edge of the flange 22b to be larger than the interval W1 between the adjacent ribs 31a and 31a of the transmission belt 31, it is possible to prevent the rib 31a of the transmission belt 31 from being lost. .

  In the above, a water pump has been described as an example of an auxiliary machine, but the auxiliary machine may be an alternator, a power steering pump, an air conditioner compressor, or the like.

  Further, the case where the present invention is applied to a power transmission mechanism that transmits power between two axes has been described above, but the present invention can also be applied to a power transmission mechanism that transmits power between three or more axes. it can. That is, the present invention can also be applied to a power transmission mechanism including one crank pulley, two or more auxiliary machine pulleys, and a transmission belt that is spanned between these pulleys.

  In the above description, the crank pulley is rotated using the ratchet handle during the assembly operation of the transmission belt. However, the transmission belt may be assembled by rotating a pulley other than the crank pulley.

  In the above, the V-ribbed belt has been described as an example of the transmission belt, but the transmission belt may be a V-belt (a belt having a trapezoidal cross section).

  Although the case where the present invention is applied to the power transmission mechanism for driving the auxiliary machinery of the engine mounted on the vehicle has been described above, the present invention is not limited to this. For example, the present invention can be applied to a power transmission mechanism in which a drive source is an electric motor, and further, a structure in which a low-elasticity transmission belt is stretched between a drive pulley and a driven pulley. The present invention can also be applied to other various power transmission mechanisms.

  INDUSTRIAL APPLICABILITY The present invention can be used for a power transmission mechanism that includes a plurality of pulleys and a transmission belt that is spanned between the pulleys. The present invention can also be used in a belt assembling method for assembling a transmission belt between pulleys in a power transmission mechanism including a plurality of pulleys and a transmission belt stretched between the pulleys.

DESCRIPTION OF SYMBOLS 10 Power transmission mechanism 12 Crank pulley 12a Pulley groove 12b Flange 22 Water pump pulley 22a Pulley groove 22b Flange 24 Projection 24a Outer surface 25 Front surface (surface on one side in the axial direction)
31 Transmission belt 31a Rib 40 Ratchet handle

Claims (8)

In a power transmission mechanism comprising a plurality of pulleys and a transmission belt spanned between these pulleys,
Among the plurality of pulleys, a projection on one side in the axial direction of one pulley is provided so as to protrude toward one side in the axial direction when the transmission belt is assembled between the pulleys. The power transmission mechanism is characterized in that the protrusion is disposed concentrically with the one pulley. The power transmission mechanism according to claim 1,
The protrusion is formed with a larger diameter as the length of the transmission belt is longer. The power transmission mechanism according to claim 1 or 2,
On one side in the axial direction of the one pulley, a flange is provided that protrudes to the outer diameter side from the pulley groove into which the transmission belt is fitted.
A power transmission mechanism, wherein an outer peripheral edge on one axial side of the flange has an R shape. In the power transmission mechanism according to claim 3,
The transmission belt is a V-ribbed belt having a plurality of ribs extending in the belt length direction,
A power transmission mechanism, wherein a radius of curvature of the outer peripheral edge is set to be larger than an interval between adjacent ribs of the transmission belt. In the power transmission mechanism according to claim 4,
The power transmission mechanism, wherein the one pulley is a crank pulley attached to one end portion of an engine crankshaft. In a power transmission mechanism comprising a plurality of pulleys and a transmission belt spanned between these pulleys, a belt assembling method for assembling the transmission belt between the plurality of pulleys,
Of the plurality of pulleys, on one surface in the axial direction of one pulley, a protrusion protruding toward the one axial side is disposed concentrically with the one pulley,
The transmission belt is wound around a pulley other than the one pulley among the plurality of pulleys, and the transmission belt is hooked on the outer peripheral surface of the protrusion while being wound around the one pulley.
A belt assembling method in a power transmission mechanism, wherein one of a plurality of pulleys is rotated while pressing the transmission belt so as to secure a winding length of the transmission belt around the one pulley. In the belt assembly method in the power transmission mechanism according to claim 6,
On one side in the axial direction of the one pulley, a flange is provided that protrudes to the outer diameter side from the pulley groove into which the transmission belt is fitted.
When the transmission belt is hooked on the outer peripheral surface of the protrusion, the transmission belt is run on the flange at a position upstream of the central position of the region where the transmission belt of the one pulley can be wound, in the pulley rotation direction, A belt assembling method in a power transmission mechanism, characterized in that a transmission belt that rides on the flange is hooked on an outer peripheral surface of a protrusion on an inner diameter side of the flange. In the belt assembly method in the power transmission mechanism according to claim 7,
A belt assembling method in a power transmission mechanism, wherein when one of the plurality of pulleys is rotated, a portion of the transmission belt that rides on a flange is pressed down.

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