Belt mounting jig

Abstract

To provide a belt mounting jig that allows for easy belt installation while preventing damage to the belt. [Solution] The belt mounting jig 6 has a belt pressing portion 62 shaped along a first arc AR1, a pulley pressing portion 61 shaped along a second arc AR2 concentric with the center ARO of the first arc AR1, a belt holding portion 64 extending inward from the first arc AR1, and a connecting portion 65 shaped along a third arc AR3 concentric with the center ARO of the first arc AR1, connecting the belt pressing portion 62, the pulley pressing portion 61, and the belt holding portion 64. In the connecting direction of the connecting portion 65, a belt insertion hole 63 is formed between the belt pressing portion 62 and the pulley pressing portion 61. When the central angle of the belt pressing portion 62 is central angle C, the central angle of the belt insertion hole 63 is central angle B, and the central angle of the pulley pressing portion 61 is central angle A, central angle B is 18° or more, and the sum of the angles of central angle A, central angle B, and central angle C is 90° or less.

Description

Technical Field

[0001] The present invention relates to a belt mounting jig that is installed on the outer circumference of a pulley for wrapping a belt around the pulley. Background Art

[0002] Some belt transmission mechanisms have a layout in which, for example, the center distance between a plurality of pulleys to which a belt is mounted is fixed, and no tension applying mechanism such as a tension pulley or a tensioner is used. In such a belt transmission mechanism, in order to reliably transmit power between the pulleys, the circumferential length of the belt is set to be shorter than the layout circumferential length between the plurality of pulleys to which the belt is mounted, so that a predetermined tension acts on the belt.

[0003] When attaching a belt between such a plurality of pulleys, a method may be employed in which the belt is wrapped around all pulleys except one remaining pulley, and then, while applying tension to the belt using a belt mounting jig, the last remaining pulley is rotated to wrap the belt around the outer circumference of the pulley.

[0004] As a belt mounting jig used in such a belt mounting method, for example, a belt mounting jig that is arranged along the outer circumference of a pulley and guides a belt to a predetermined path is known. Since such a belt mounting jig is used while being disposed on the outer circumference of the pulley, it may have a shape corresponding to the outer circumferential shape of the pulley. By using such a belt mounting jig, the pulley can be rotated while holding the belt along the outer circumference of the pulley, so the belt can be wrapped around the pulley relatively easily. Patent Document 1 discloses a belt mounting jig including a pulley pressing portion that presses against the outer circumference of the pulley, a belt pressing portion that presses the belt, and a belt holding portion that holds the belt. Prior Art Documents Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-249312 [Overview of the project] [Problems that the invention aims to solve]

[0006] The belt mounting jig described in Patent Document 1 is used in a state where it is positioned along the outer circumference of the pulley. The belt, held in place by the belt retaining portion, is then guided to the pulley pressing portion and then placed over the belt holding portion, thereby forming a belt path for wrapping the belt around the pulley.

[0007] However, depending on the positional relationship between the belt retainer and the pulley pressing part, the belt may be excessively deflected and deformed when guided from the belt retainer to the pulley pressing part. As a result, an excessive load may be applied to the belt, potentially leading to belt damage.

[0008] Furthermore, in order to attach the belt, which is held in place by the belt retainer, to the belt holder via the pulley pressing section, tension must be applied to the belt. However, depending on the relative positions of the belt retainer, pulley pressing section, and belt holder, the belt tension required to attach the belt to the belt holder may become excessively large, making it difficult to attach the belt to the belt holder.

[0009] Furthermore, in recent years, with the diversification of belt transmission mechanisms, pulley layouts and belt specifications have also become more diverse. Consequently, various shapes of belt mounting fixtures are used, but guidelines for designing belt mounting fixtures that take into account belt deflection and the belt tension required when attaching the belt to the belt holder have not always been clear.

[0010] Therefore, the present invention aims to provide a belt mounting jig that can easily mount a belt while preventing damage to the belt, by suppressing excessive deflection deformation of the belt and excessive increase in belt tension when guiding the belt, which is held in place by the belt retaining portion, to the belt holding portion via the pulley pressing portion. [Means for solving the problem]

[0011] One invention for solving the above problem is a belt mounting jig, which is installed on the outer circumference of a first pulley and used when winding a circumferentially expandable belt, which is wound around a plurality of pulleys with a fixed distance between their axes, leaving one pulley unwound, onto the remaining pulley, the first pulley, A belt retaining portion shaped along the first arc, A pulley pressing portion having a shape along a second arc concentric with the center of the first arc, A belt retaining portion extending toward the inside of the first arc, A connecting portion that connects the belt retaining portion, the pulley pressing portion, and the belt holding portion in that order, having a shape along a third arc concentric with the center of the first arc, It has, In the connection direction of the aforementioned connecting portion, a belt insertion hole is formed between the belt retaining portion and the pulley pressing portion. When the central angle of the belt retaining portion is central angle C, the central angle of the belt insertion hole is central angle B, and the central angle of the pulley pressing portion is central angle A, This belt mounting jig is characterized in that the central angle B is 18° or greater, and the sum of the angles of central angles A, B, and C is 90° or less.

[0012] With the belt mounting jig configured as described above, since the pulley pressing portion is shaped along the second arc, the pulley pressing portion can be positioned along the outer circumferential surface of the first pulley. Also, since the belt retaining portion is shaped along the first arc, the belt retaining portion can be pressed along the belt positioned along the outer circumferential surface of the first pulley. Furthermore, a path can be formed to guide the belt, which is held in place by the belt retaining portion, to the pulley pressing portion through the belt insertion hole, and then to the belt holding portion. Here, if the central angle B occupied by the belt insertion hole is less than 18°, the length of the section that guides the belt, held in place by the belt retainer, to the pulley pressing section becomes shorter, causing the belt to flex and deform significantly in this section. As a result, there is a risk of belt damage. Furthermore, if the sum of the angles of central angles A, B, and C exceeds 90°, the path from the belt held by the belt retainer to the belt holder via the pulley pressing section becomes longer, resulting in excessively high belt tension required to secure the belt to the belt holder. Consequently, securing the belt to the belt holder may become difficult. In contrast, by setting the central angle B to 18° or more, and the sum of the angles of central angles A, B, and C to 90° or less, excessive deflection deformation of the belt and excessive increase in belt tension can be suppressed. This prevents damage to the belt and allows the belt to be easily attached to the belt holder, thus enabling easy attachment of the belt to the first pulley.

[0013] Furthermore, in the belt mounting jig described above, the present invention provides a component installed on the outer circumference of the first pulley such that the center of the first arc is located on the axis of the first pulley, When the belt is wrapped around the first pulley, the belt retaining portion may press the first portion of the belt against the outer circumferential surface of the first pulley, the pulley pressing portion may be pressed against the outer circumferential surface of the first pulley by the second portion of the belt, and the belt holding portion may hook and hold the third portion of the belt.

[0014] According to the above configuration, since the belt mounting jig is installed such that the center of the first arc is positioned on the shaft of the first pulley, the belt pressing portion, the belt insertion hole, the pulley pressing portion and the belt holding portion can be arranged in an appropriate positional relationship along the outer circumference of the first pulley. Therefore, a path for guiding the belt pressed by the belt pressing portion to the pulley pressing portion via the belt insertion hole and further guiding the belt to the belt holding portion can be appropriately formed. This enables smooth mounting of the belt onto the first pulley.

[0015] Further, in the above-mentioned belt mounting jig, the present invention may be characterized in that the central angle A is 18° or more.

[0016] According to the above configuration, by setting the central angle A to 18° or more, a sufficient circumferential length occupied by the pulley pressing portion can be secured. Therefore, a sufficient length of the belt portion to be hung on the pulley pressing portion can be secured, and the belt pressed by the belt pressing portion can be stably hung on the pulley pressing portion.

[0017] Further, in the above-mentioned belt mounting jig, the present invention may be characterized in that the central angle C is 12° or more.

[0018] According to the above configuration, by setting the central angle C to 12° or more, a sufficient circumferential length occupied by the belt pressing portion can be secured. Therefore, a sufficient length of the belt portion pressed by the belt pressing portion can be secured, and the belt can be stably pressed.

[0019] Further, in the above-mentioned belt mounting jig, the present invention may be characterized in that the total angle of the central angle A, the central angle B and the central angle C is 75° or less.

[0020] According to the above configuration, by setting the total angle of the central angle A, the central angle B, and the central angle C to 75° or less, the belt tension required for wrapping the belt held by the belt holding portion around the belt retaining portion via the pulley pressing portion can be further reduced. This allows the belt to be more easily wrapped around the belt retaining portion.

[0021] Further, in the belt attachment jig of the present invention, the second arc may have the same diameter as the third arc, and the first arc may have a different diameter from the third arc.

[0022] According to the above configuration, by making the diameter of the second arc equal to that of the third arc, the portion from the connecting portion to the pulley pressing portion can be formed smoothly. Therefore, when the belt is wrapped around the pulley pressing portion, the load acting on the belt attachment jig from the belt can be easily distributed to the connecting portion and the pulley pressing portion, and an increase in local stress occurring in the belt attachment jig can be suppressed. Further, by making the diameter of the first arc different from that of the third arc, a radial positional difference can be formed between the belt holding portion and the pulley pressing portion. Therefore, a belt path for guiding the belt held by the belt holding portion to the pulley pressing portion via the belt insertion hole can be formed. This allows the belt held by the belt holding portion to be smoothly guided to the belt retaining portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] [Figure 1] FIG. 1 is a partial perspective view of an accessory drive unit around which a belt is wrapped by a belt attachment jig. [Figure 2] FIG. 2 is a view explaining the structure of a crank pulley included in the accessory drive unit of FIG. 1. [Figure 3] FIG. 3 is a perspective view of a belt attachment jig according to a first embodiment. [Figure 4] FIG. 4 is a six-view drawing of the belt attachment jig according to the first embodiment. [Figure 5] FIG. 5 is a front view of the belt attachment jig according to the first embodiment. [Figure 6] Figure 5 shows the cross-sectional views of JJ, KK, and LL. [Figure 7] These are views taken along arrows M, N, and O in Figures 5 and 6. [Figure 8] This diagram shows the belt mounting jig installed on the outer circumference of the crank pulley. [Figure 9] This diagram shows a V-ribbed belt hooked onto the belt holding part of a belt mounting jig installed on the outer circumference of the crank pulley. [Figure 10] (A) This diagram illustrates the radial relationship between the belt mounting jig and the V-ribbed belt. (B) This diagram illustrates the deformation of the V-ribbed belt when using the belt mounting jig. [Figure 11] This is an explanatory diagram showing how to use the belt mounting jig. [Figure 12] This is an explanatory diagram showing how to use the belt mounting jig. [Figure 13] This is an explanatory diagram showing how to use the belt mounting jig. [Figure 14] This is an explanatory diagram showing how to use the belt mounting jig. [Figure 15] This is an explanatory diagram showing how to use the belt mounting jig. [Figure 16] This is a perspective view of the belt mounting jig according to the second embodiment. [Figure 17] This is a six-view drawing of a belt mounting jig according to the second embodiment. [Figure 18] This is a front view of the belt mounting jig according to the second embodiment. [Figure 19] Figure 18 shows a cross-sectional view of the PP section and a view of the PP section from the perspective of arrow QQ. [Figure 20] (A) This is an explanatory diagram of the pressing mechanism of the belt onto the belt mounting jig according to Example 2. (B) This is the result of the 3D finite element method (FEM) analysis of the belt mounting jig of Example 2. [Figure 21] (A) This is an explanatory diagram of the pressing mechanism of the belt onto the belt mounting jig according to Example 1. (B) This is the result of the 3D finite element method (FEM) analysis of the belt mounting jig of Example 1. [Modes for carrying out the invention]

[0024] (First Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

[0025] (Auxiliary drive unit 1) As shown in Figure 1, the auxiliary drive unit 1 is rotatably supported by a crank pulley 2 (corresponding to the first pulley) connected to the engine's crankshaft and an alternator pulley 3 (corresponding to at least one pulley) connected to the alternator's input shaft, separated by a predetermined distance between the shafts. A V-ribbed belt 4 is wrapped around the crank pulley 2 and the alternator pulley 3. As a result, power from the crankshaft is transmitted to the alternator via the crank pulley 2, the V-ribbed belt 4, and the alternator pulley 3.

[0026] The belt mounting jig 6 according to the first embodiment is used when winding a circumferentially expandable belt, which has been wound around multiple pulleys with fixed interaxial distances from each other, onto the remaining pulley, the first pulley, and is installed on the outer circumference of the first pulley. In the first embodiment, the belt mounting jig 6 is used in the auxiliary drive unit 1 shown in Figure 1 to wrap the V-ribbed belt 4, which is wound around the alternator pulley 3, around the crank pulley 2. Furthermore, the belt mounting jig 6 may be used to wrap a belt that is already wrapped around two or more pulleys around another pulley.

[0027] Furthermore, the pulley on which the belt mounting jig 6 is installed is not particularly limited. The pulley on which the belt mounting jig 6 is installed may be, for example, an air conditioner compressor pulley or a water pump pulley used in an auxiliary drive unit of an automobile engine. In addition, the pulley on which the belt mounting jig 6 is installed may be a pulley of a device other than an auxiliary drive unit.

[0028] (Crank pulley 2, alternator pulley 3) As shown in Figure 1, the auxiliary drive unit 1 supports a crank pulley 2 connected to the engine's crankshaft and an alternator pulley 3 connected to the alternator's input shaft, both rotatably separated by a predetermined distance between their shafts. A V-ribbed belt 4, shown by solid and dashed lines, is wrapped around the crank pulley 2 and the alternator pulley 3. As a result, power from the crankshaft is transmitted to the alternator's input shaft sequentially via the crank pulley 2, the V-ribbed belt 4, and the alternator pulley 3. The distance between the crank pulley 2 and the alternator pulley 3 is fixed, and as shown in Figure 1, there is no so-called auto-tensioner to apply tension to the V-ribbed belt 4.

[0029] As shown in Figure 2, the outer circumference of the crank pulley 2 has multiple pulley grooves 2a that can engage with multiple ribs formed on the inner surface of the V-ribbed belt 4. The crank pulley 2 also has a pair of pulley flanges 2b that sandwich the multiple pulley grooves 2a in the width direction of the crank pulley 2. In the cross-sectional view of Figure 2, these pulley flanges 2b are formed to protrude slightly radially outward from the pulley grooves 2a. The crankshaft of the engine (not shown) is inserted into the boss portion 5 of the crank pulley 2. Sides 2c and 2d show the two sides of the crank pulley 2. Furthermore, the alternator pulley 3 has the same configuration as the crank pulley 2.

[0030] (V-ribbed belt 4) The V-ribbed belt 4 is a belt that is slightly stretchable in its circumferential direction. In this embodiment, a so-called low-modulus V-ribbed belt 4 is used as a specific example of the belt. Low-modulus belts use polyamide fibers in their core to achieve a relatively low modulus of elasticity, which suppresses the rapid decrease in tension compared to high-modulus belts with a high modulus of elasticity. The V-ribbed belt 4 has a belt circumference shorter than the layout circumference between the crank pulley 2 and the alternator pulley 3, so that tension is applied to the V-ribbed belt 4 in the circumferential direction. The layout circumference refers to the length of the ring-shaped line formed along the outer circumference to connect the outer circumferences of each pulley in two or more pulleys.

[0031] Furthermore, the inner circumferential surface of the V-ribbed belt 4 has multiple ribs formed along the circumferential direction that can be fitted into multiple pulley grooves 2a formed on the outer circumference of the crank pulley 2.

[0032] (Belt mounting jig 6) Figure 3 is a perspective view of the belt mounting jig 6, Figure 4 is a six-view drawing of the belt mounting jig 6, and Figure 5 is a schematic diagram showing the belt mounting jig 6 as viewed in its width direction.

[0033] As shown in Figures 3 to 5, the belt mounting jig 6 includes a pulley pressing portion 61, a belt holding portion 62, a belt insertion hole 63, a belt holding portion 64, and a connecting portion 65.

[0034] The belt retaining portion 62 has a shape that follows the first arc AR1 when viewed in the width direction of the belt mounting jig 6. The pulley pressing portion 61 has a shape that follows the second arc AR2, which is concentric with the center ARO of the first arc AR1, when viewed in the width direction of the belt mounting jig 6. The connecting portion 65 has a shape that follows the third arc AR3, which is concentric with the center ARO of the first arc AR1, when viewed in the width direction of the belt mounting jig 6. Furthermore, the first arc AR1, the second arc AR2, and the third arc AR3 are set to have a center ARO that substantially coincides with the rotational axis DC of the crank pulley 2 when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2. When the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2, the width direction of the belt mounting jig 6 coincides with the width direction of the crank pulley 2.

[0035] As shown in Figure 5, the first arc AR1, the second arc AR2, and the third arc AR3 share a common center ARO. Hereinafter, the first arc AR1, the second arc AR2, the third arc AR3, the center ARO, and the central angles A, B, and C are defined in terms of the belt mounting jig 6 viewed in its width direction, unless otherwise specified. Furthermore, the first arc AR1, the second arc AR2, and the third arc AR3 are arcs that define the contours of the belt retaining portion 62, the pulley pressing portion 61, and the connecting portion 65, respectively, when viewed in their width direction, on the side furthest from the center ARO.

[0036] The connecting portion 65 connects the belt retaining portion 62, the pulley pressing portion 61, and the belt holding portion 64. In this embodiment, the direction from the belt retaining portion 62 through the pulley pressing portion 61 to the belt holding portion 64 along the connecting portion 65 is referred to as the connecting direction of the connecting portion 65.

[0037] The belt retaining portion 62, the belt insertion hole 63, the pulley pressing portion 61, and the belt holding portion 64 are arranged in this order along the connection direction. The belt insertion hole 63 is formed between the belt retaining portion 62 and the pulley pressing portion 61 in the connection direction. The belt insertion hole 63 is formed as an opening to guide the V-ribbed belt 4, which is held down by the belt retaining portion 62, to the pulley pressing portion 61.

[0038] The belt retaining portion 64 is formed to extend inward toward the first arc AR1. Furthermore, the belt holding portion 64 is formed to be able to hook and hold a part of the belt. A folded portion 641 may be formed in the belt holding portion 64. The folded portion 641 may be formed by bending from the end of the connecting portion 65, or it may be formed in an arc shape or a substantially arc shape. A portion of the V-ribbed belt 4 can be hooked onto the folded portion 641. Therefore, the V-ribbed belt 4 can be stably held by the belt holding portion 64.

[0039] The belt retaining portion 62 is the part that holds a portion of the V-ribbed belt 4 from the outer circumference. The pulley pressing portion 61 is the part that is pressed toward the outer circumferential surface of the first pulley by receiving tension from the V-ribbed belt 4 that is placed over it.

[0040] As shown in Figure 5, central angles A, B, and C are all defined with respect to the center ARO. Central angle C is the angle occupied by the belt retainer 62 along the first arc AR1. Central angle B is the angle occupied by the belt insertion hole 63. Central angle A is the angle occupied by the pulley pressing part 61 along the second arc AR2. In other words, central angle C is the angle corresponding to the arc length of the belt retainer 62, central angle B is the angle corresponding to the arc length of the belt insertion hole 63, and central angle A is the angle corresponding to the arc length of the pulley pressing part 61. Furthermore, central angles A, B, and C represent the angular ranges occupied in the circumferential direction by the pulley pressing part 61, the belt insertion hole 63, and the belt retainer 62, respectively, in the belt mounting jig 6.

[0041] In this embodiment, central angle B is set to 18° or greater. Also, the sum of central angles A, B, and C is set to 90° or less.

[0042] The larger the central angle B, the longer the arc length of the section that guides the V-ribbed belt 4, held down by the belt retaining section 62, to the pulley pressing section 61 through the belt insertion hole 63. Conversely, the smaller the central angle B, the shorter the arc length of that section.

[0043] Furthermore, the larger the central angle A, the longer the arc length of the pulley pressing portion 61, and the larger the central angle C, the longer the arc length of the belt retaining portion 62. In addition, the sum of the central angles A, B, and C defines the circumferential range from the belt retaining portion 62 through the belt insertion hole 63 to the pulley pressing portion 61.

[0044] In this embodiment, central angle A is set to 18° or greater. Also, central angle C is set to 12° or greater. Furthermore, the sum of central angles A, B, and C may be set to 75° or less.

[0045] In this embodiment, the diameter of the first arc AR1 (diameter D shown in Figure 5) and the diameter of the second arc AR2 (diameter E shown in Figure 5) are set to be smaller than the diameter of the third arc AR3 (diameter F shown in Figure 5). In other words, when viewing the belt retaining portion 62, the pulley pressing portion 61, and the connecting portion 65 in their width direction, the radius of curvature of the contour on the side furthest from the center ARO is largest for the connecting portion 65. For this reason, as shown in Figures 6 and 7, the belt retaining portion 62 and the pulley pressing portion 61 are located closer to the center ARO than the connecting portion 65. Furthermore, the diameter (diameter E) of the second arc AR2 is set to be smaller than the diameter (diameter D) of the first arc AR1, and this difference in diameter is set based on the dimension corresponding to the thickness of the V-ribbed belt 4. This allows the pulley pressing portion 61 to be pressed toward the outer surface of the pulley via the V-ribbed belt 4 that is placed over the pulley pressing portion 61, while the V-ribbed belt 4 is pressed toward the outer surface of the pulley by the belt retaining portion 62. Therefore, it is possible to achieve both the pressing of the V-ribbed belt 4 by the belt pressing portion 62 and the guiding of the V-ribbed belt 4 by the pulley pressing portion 61.

[0046] As shown in Figures 6 and 7, the pulley pressing portion 61 is connected to the connecting portion 65 via the first connecting portion 614. The first connecting portion 614 has a first fold 611 and a second fold 612 formed therein. The first connecting portion 614 is located between the first fold 611 and the second fold 612. Furthermore, the belt retaining portion 62 is connected to the connecting portion 65 via the second connecting portion 624. The second connecting portion 624 has a third fold 621 and a fourth fold 622 formed thereon. The second connecting portion 624 is located between the third fold 621 and the fourth fold 622. The first connecting portion 614 and the second connecting portion 624 each have steps radially inward relative to the connecting portion 65, formed by the first fold 611, the second fold 612, the third fold 621, and the fourth fold 622. As a result, the pulley pressing portion 61 and the belt holding portion 62 are located closer to the center ARO than the connecting portion 65.

[0047] Let H be the radial length of the first connecting portion 614, and I be the radial length of the second connecting portion 624. In this embodiment, the radial length H of the first connecting portion 614 is set to be greater than the radial length I of the second connecting portion 624. Furthermore, in this embodiment, the difference between the radial length H of the first connecting portion 614 and the radial length I of the second connecting portion 624 is set based on a dimension corresponding to the thickness of the V-ribbed belt 4.

[0048] Furthermore, the belt mounting jig 6 may also include a first contact portion 651, a second contact portion 616, and a third contact portion 642, as in this embodiment.

[0049] The first contact portion 651 is formed at one end of the connecting portion 65. The first contact portion 651 contacts the side surface 2d of the crank pulley 2 when the belt mounting jig 6 is installed on the crank pulley 2. As shown in Figures 6 and 7, the second contact portion 616 is formed to extend radially inward from the pulley pressing portion 61. The second contact portion 616 contacts the side surface 2c of the crank pulley 2 when the belt mounting jig 6 is installed on the crank pulley 2. The third contact portion 642 is formed on the belt holding portion 64. The third contact portion 642 contacts the side surface 2d of the crank pulley 2 when the belt mounting jig 6 is installed on the crank pulley 2. The first contact portion 651 and the third contact portion 642 contact one side of the crank pulley 2, and the second contact portion 616 contacts the other side of the crank pulley 2, thereby allowing the belt mounting jig 6 to be positioned in the width direction of the crank pulley 2. This allows the belt mounting jig 6 to be stably installed on the crank pulley 2.

[0050] (Numerical ranges for central angle A, central angle B, and central angle C) In this embodiment, as shown in Figure 5, central angle A is 20°, central angle B is 27°, and central angle C is 15°. However, in the belt mounting jig 6, if central angle B is 18° or more, and the sum of the angles of central angles A, B, and C is 90° or less, the values ​​of central angles A, B, and C are not limited to the above values.

[0051] Furthermore, in the belt mounting jig 6, it is preferable that the central angle A is 18° or greater. By setting the central angle A to 18° or more, the circumferential length occupied by the pulley pressing portion 61 can be sufficiently secured. Therefore, the length of the V-ribbed belt 4 that is placed over the pulley pressing portion 61 can be sufficiently secured, and the V-ribbed belt 4 can be stably guided to the pulley pressing portion 61.

[0052] Furthermore, in the belt mounting jig 6, it is preferable that the central angle C is 12° or greater. By setting the central angle C to 12° or more, the circumferential length occupied by the belt retaining portion 62 can be sufficiently secured. Therefore, the length of the V-ribbed belt 4 held down by the belt retaining portion 62 can be sufficiently secured, and the V-ribbed belt 4 can be held down stably.

[0053] As stated above, since central angles A ≥ 18°, B ≥ 18°, and C ≥ 12°, The condition Central angle A + Central angle B + Central angle C ≥ 48° holds true. Furthermore, since central angle A ≥ 18°, central angle C ≥ 12°, and central angle A + central angle B + central angle C ≤ 90°, the central angle B ≤ 60° holds true. Furthermore, since central angle B ≥ 18°, central angle C ≥ 12°, and central angle A + central angle B + central angle C ≤ 90°, the central angle A ≤ 60° holds true. Furthermore, since central angle A ≥ 18°, central angle B ≥ 18°, and central angle A + central angle B + central angle C ≤ 90°, the condition C ≤ 54° holds. Therefore, the following ranges are preferable: 18° ≤ central angle A ≤ 60°, 18° ≤ central angle B ≤ 60°, 12° ≤ central angle C ≤ 54°, and 48° ≤ central angle A + central angle B + central angle C ≤ 90°.

[0054] Here, the central angle B relates to the section in which the V-ribbed belt 4, held down by the belt retaining portion 62, is guided to the pulley pressing portion 61 through the belt insertion hole 63. Therefore, focusing solely on the viewpoint of suppressing large radial outward deflection deformation of the V-ribbed belt 4 at the point where it transitions from the belt holding portion 62 to the pulley pressing portion 61, it is preferable for the central angle B to be as large as possible. Specifically, if central angle A is 18° and central angle C is 12°, then central angle B will be 60°. This condition is an example of a suitable condition from the viewpoint of suppressing deflection deformation of the V-ribbed belt 4.

[0055] However, in the belt mounting jig 6, it is necessary to consider not only the suppression of deflection deformation of the V-ribbed belt 4, but also the prevention of rib displacement of the V-ribbed belt 4 and the compactness of the belt mounting jig 6. Therefore, in this embodiment, taking these factors into consideration, central angle A is set to 20°, central angle B to 27°, and central angle C to 15°.

[0056] Furthermore, in the belt mounting jig 6, it is more preferable that the sum of the angles of central angle A, central angle B, and central angle C is 75° or less. By making the sum of the angles of central angles A, B, and C 75° or less, the tension required to hang the V-ribbed belt 4, which is held down by the belt retaining portion 62, onto the belt holding portion 64 via the pulley pressing portion 61 can be reduced. Therefore, the V-ribbed belt 4 can be more easily attached to the belt holding part 64.

[0057] As shown above, since central angles A ≥ 18°, B ≥ 18°, and C ≥ 12°, the equation A + B + C ≥ 48° holds true. Furthermore, since central angle A ≥ 18°, central angle C ≥ 12°, and central angle A + central angle B + central angle C ≤ 75°, the central angle B ≤ 45° holds true. Furthermore, since central angle B ≥ 18°, central angle C ≥ 12°, and central angle A + central angle B + central angle C ≤ 75°, the central angle A ≤ 45° holds true. Furthermore, since central angle A ≥ 18°, central angle B ≥ 18°, and central angle A + central angle B + central angle C ≤ 75°, the condition C ≤ 39° holds. Therefore, the ranges 18° ≤ central angle A ≤ 45°, 18° ≤ central angle B ≤ 45°, 12° ≤ central angle C ≤ 39°, and 48° ≤ central angle A + central angle B + central angle C ≤ 75° are more preferable.

[0058] In this regard, if we focus solely on the viewpoint of suppressing large radial outward deflection deformation in the portion of the V-ribbed belt 4 from the position where it is held down by the belt retaining portion 62 until it rides up onto the pulley pressing portion 61, it is preferable to make the central angle B as large as possible. Specifically, if central angle A is 18° and central angle C is 12°, then central angle B will be 45°. This condition is an example of a suitable condition from the viewpoint of suppressing deflection deformation of the V-ribbed belt 4. However, considering the suppression of deflection deformation of the V-ribbed belt 4, the prevention of rib displacement of the V-ribbed belt 4, and the compactness of the belt mounting jig 6, it is preferable to set the central angle A to 20°, the central angle B to 27°, and the central angle C to 15°, as in this embodiment.

[0059] As described above, the belt mounting jig 6 of this embodiment can suppress excessive deflection deformation and excessive increase in tension of the V-ribbed belt 4. As a result, the V-ribbed belt 4 can be easily installed while preventing damage to the V-ribbed belt 4.

[0060] (Belt attachment method) Next, referring to Figures 11 to 15, we will explain how to wrap a V-ribbed belt 4, which is already wrapped around the alternator pulley 3 but not yet around the crank pulley 2, around the crank pulley 2 using a belt mounting jig 6, with respect to the crank pulley 2 and alternator pulley 3, whose shaft distances from each other are fixed. In the following explanation, the centerline of the rotation axis of the crank pulley 2 will be referred to as the rotation axis DC of the crank pulley 2. The radial direction of the crank pulley 2 will simply be referred to as the radial direction, the side of the rotation axis DC in the radial direction will be referred to as the radially inner side, and the side opposite the rotation axis DC in the radial direction will be referred to as the radially outer side. The width direction of the crank pulley 2 will be the direction parallel to the rotation axis DC.

[0061] (Procedure (a)) First, connect the wrench 13 to the boss portion 5 of the crank pulley 2 so that the crank pulley 2 can be freely rotated by hand.

[0062] (Procedure (b)) Next, the V-ribbed belt 4 is wrapped around the alternator pulley 3. Then, a portion of the V-ribbed belt 4 is positioned along the outer circumference of the crank pulley 2 so that the multiple ribs formed on the inner surface of the V-ribbed belt 4 fit into the pulley groove 2a of the crank pulley 2. Then, the belt retaining portion 62 of the belt mounting jig 6 is placed on the outer surface of the V-ribbed belt 4, and the V-ribbed belt 4 is inserted through the belt insertion hole 63. Then, the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2. At this time, the belt mounting jig 6 is positioned such that the center ARO of the first arc AR1 lies on the rotational axis DC of the crank pulley 2. Furthermore, the first contact portion 651 and the third contact portion 642 are brought into contact with the side surface 2d of the crank pulley 2, and the second contact portion 616 is brought into contact with the side surface 2c of the crank pulley 2. As a result, the belt mounting jig 6 is held by sandwiching the crank pulley 2 from both sides in the width direction. Therefore, the belt mounting jig 6 can be stably installed on the crank pulley 2.

[0063] Next, the V-ribbed belt 4 is positioned so that a portion of it is pressed against the outer surface of the crank pulley 2 by the belt retaining portion 62, as shown in Figures 9 and 11. Furthermore, another portion of the V-ribbed belt 4 is pulled radially outward through the belt insertion hole 63 and placed on the pulley pressing portion 61. Furthermore, another portion of the V-ribbed belt 4 is hooked onto the belt holding portion 64 for retention.

[0064] Here, the portion of the V-ribbed belt 4 that is pressed against the outer surface of the crank pulley 2 by the belt retaining portion 62 is designated as the first portion 4a. The portion of the V-ribbed belt 4 that is placed over the pulley pressing portion 61 is designated as the second portion 4b. The portion of the V-ribbed belt 4 that is hooked onto the belt holding portion 64 is designated as the third portion 4c.

[0065] In this state, the belt retaining portion 62 presses the first portion 4a of the V-ribbed belt 4 against the outer circumferential surface of the crank pulley 2, as shown in Figures 10(A) and 10(B). Furthermore, the second portion 4b of the V-ribbed belt 4 is placed over the pulley pressing portion 61, and the tension of the second portion 4b presses the pulley pressing portion 61 against the outer circumferential surface of the crank pulley 2. Furthermore, as shown in Figure 10(B), the belt holding portion 64 hooks onto and holds the third portion 4c of the V-ribbed belt 4. In this way, the belt mounting jig 6 forms a path for the V-ribbed belt 4 with the belt pressing portion 62, belt insertion hole 63, pulley pressing portion 61, and belt holding portion 64, and holds the V-ribbed belt 4 in a state that allows it to be wrapped around the crank pulley 2. Furthermore, in this state, the first part 4a, the second part 4b, and the third part 4c act on the belt retaining part 62, the pulley pressing part 61, and the belt holding part 64, respectively, so that the belt mounting jig 6 can be held in a stable position relative to the outer circumference of the crank pulley 2. Therefore, it is possible to prevent the belt mounting jig 6 from unintentionally tilting or shifting position before the crank pulley 2 starts to rotate.

[0066] Here, if the central angle B is less than 18°, the length of the section transitioning from the first part 4a to the second part 4b of the V-ribbed belt 4 becomes shorter. Therefore, as shown in Figure 10(B), the inclination angle β of the V-ribbed belt 4 increases in the section from the first part 4a through the second part 4b to the third part 4c. As the inclination angle β increases, a sharp bend occurs in the V-ribbed belt 4 in the section from the first part 4a through the second part 4b to the third part 4c. As a result, as shown in Figure 10(A), the portion located between the first part 4a and the second part 4b undergoes a large deflection deformation radially outward. If the V-ribbed belt 4 is wrapped around the crank pulley 2 while such a large deflection deformation has occurred, there is a risk that the V-ribbed belt 4 will be damaged. In contrast, in this embodiment, the central angle B is set to 18° or more. Therefore, a sufficient length can be secured for the transition section from the first part 4a to the second part 4b. As a result, the increase in the inclination angle β can be suppressed, and the large radial outward deflection deformation of the V-ribbed belt 4 can be prevented, thus preventing damage to the V-ribbed belt 4.

[0067] Furthermore, if the sum of the angles of central angle A, central angle B, and central angle C exceeds 90°, the tension required to hook the V-ribbed belt 4, which is held down by the belt retaining portion 62, onto the belt holding portion 64 may become too large. Therefore, it may become difficult for the worker to hook the V-ribbed belt 4 onto the belt holding part 64, and the workability of winding the V-ribbed belt 4 onto the crank pulley 2 may decrease. In contrast, in this embodiment, the sum of the angles of central angle A, central angle B, and central angle C is set to 90° or less. Therefore, it is possible to suppress an excessive increase in tension when the V-ribbed belt 4 is hooked onto the belt holding portion 64. As a result, the V-ribbed belt 4 can be easily wrapped around the crank pulley 2.

[0068] Furthermore, if the central angle C is less than 12°, the length of the belt retaining portion 62 in pressing down on the V-ribbed belt 4 may be insufficient. Therefore, when wrapping the V-ribbed belt 4 around the crank pulley 2, the V-ribbed belt 4 tends to lift off the outer circumference of the crank pulley 2, and the V-ribbed belt 4 may shift on the outer circumference of the crank pulley 2. In contrast, in this embodiment, the central angle C is set to 12° or more. Therefore, the belt retaining portion 62 can hold the V-ribbed belt 4 over a sufficient length. As a result, it is possible to suppress the V-ribbed belt 4 from lifting off the outer circumference of the crank pulley 2, thereby preventing rib displacement.

[0069] Furthermore, in this embodiment, the diameter (diameter E) of the second arc AR2 is set to be smaller than the diameter (diameter D) of the first arc AR1, and this difference in diameter is set based on the dimension corresponding to the thickness of the V-ribbed belt 4. Therefore, the second part 4b presses the pulley pressing part 61 toward the outer circumferential surface of the crank pulley 2, while the first part 4a presses the V-ribbed belt 4 toward the outer circumferential surface of the crank pulley 2 via the belt retaining part 62. As a result, deflection deformation of the V-ribbed belt 4 can be suppressed while preventing rib displacement of the V-ribbed belt 4.

[0070] Furthermore, if the sum of central angle A and central angle B becomes small, the V-ribbed belt 4 may tilt significantly with respect to the circumferential direction of the crank pulley 2 in the section from the first part 4a through the second part 4b to the third part 4c. As a result, the V-ribbed belt 4 may bend sharply, causing the side of the V-ribbed belt 4 to deform significantly outward in the radial direction. Therefore, within the range of central angles A, B, and C described above, it is preferable to increase central angle B. This makes it possible to further suppress the deflection deformation of the V-ribbed belt 4 in the section from the first part 4a through the second part 4b to the third part 4c.

[0071] (Step (c)) Next, as shown in Figures 11 and 12, the crank pulley 2 is rotated in the rotational direction X using the wrench 13. As a result, the V-ribbed belt 4 is stretched, increasing its tension. This increased tension in the V-ribbed belt 4 acts to press the pulley pressing portion 61 against the outer surface of the crank pulley 2 via the second portion 4b. Meanwhile, the first portion 4a is pressed against the outer surface of the crank pulley 2 by the belt retaining portion 62. Therefore, the V-ribbed belt 4, the belt mounting jig 6, and the crank pulley 2 can be rotated more reliably as a single unit.

[0072] Here, if the central angle A is less than 18°, the load applied from the V-ribbed belt 4 to the pulley pressing portion 61 may be locally concentrated. As a result, a large load may act near the belt holding portion 64, and when the V-ribbed belt 4 moves away from the belt holding portion 64 and onto the outer circumference of the crank pulley 2, the V-ribbed belt 4 may not move smoothly. In addition, stress may be concentrated on a part of the belt mounting jig 6.

[0073] In contrast, in this embodiment, the central angle A is set to 18° or greater. Therefore, the pulley pressing portion 61 has sufficient circumferential length, and the load acting from the V-ribbed belt 4 can be distributed. As a result, the V-ribbed belt 4 can be smoothly detached from the belt holding portion 64, and stress concentration applied to the belt mounting jig 6 can be suppressed.

[0074] Furthermore, if the central angle A occupied by the pulley pressing portion 61 is less than 18°, the pressing force acting on the crank pulley 2 via the pulley pressing portion 61 may be locally concentrated. As a result, the load applied to the crank pulley 2 may increase. In contrast, in this embodiment, since the central angle A is set to 18° or more, the load applied to the crank pulley 2 can be suppressed.

[0075] Furthermore, as shown in Figures 12 and 13, as the crank pulley 2 continues to rotate, the V-ribbed belt 4 moves away from the belt holder 64 and onto the outer circumference of the crank pulley 2. As a result, the length of the V-ribbed belt 4 wrapped around the outer circumference of the crank pulley 2 gradually increases.

[0076] In this case as well, if the central angle A is 18° or greater, the pulley pressing portion 61 can stably guide the V-ribbed belt 4. Therefore, the V-ribbed belt 4 can be smoothly moved from the belt holding portion 64 onto the outer circumference of the crank pulley 2. As a result, it is possible to prevent the ribs of the V-ribbed belt 4 from shifting on the outer circumference of the crank pulley 2.

[0077] (Procedure (d)) Furthermore, as shown in Figures 14 and 15, as the rotation of the crank pulley 2 continues, the pressing force acting on the pulley pressing portion 61 by the second portion 4b gradually decreases. As a result, the pulley pressing portion 61 is released from being pressed against the outer surface of the crank pulley 2, and the belt mounting jig 6 can be detached from the crank pulley 2.

[0078] As the crank pulley 2 is rotated further, the pressure on the first portion 4a by the belt retainer 62 is released. As a result, the belt mounting jig 6 is discharged from the crank pulley 2 while still held by the V-ribbed belt 4. At this point, the worker can retrieve the belt mounting jig 6.

[0079] As described above, the belt mounting jig 6 of this embodiment allows the V-ribbed belt 4 to be easily wrapped around the crank pulley 2 while suppressing excessive deflection deformation and rib displacement of the V-ribbed belt 4. As a result, belt installation can be performed efficiently while suppressing damage to the V-ribbed belt 4.

[0080] The belt attached to the first pulley by the belt mounting jig 6 of the present invention is not limited to the V-ribbed belt 4. For example, the belt may be a flat belt, a multi-wedge belt, or any other belt that is stretchable in the circumferential direction.

[0081] In the belt mounting jig 6 of the present invention, the specific arrangement of the first contact portion 651, the second contact portion 616, and the third contact portion 642 can be changed as appropriate. For example, the first pulley may have a contact portion that abuts against one side of the first pulley and a contact portion that abuts against the other side of the first pulley, and the shape, number, and arrangement of each contact portion are not particularly limited.

[0082] (Second Embodiment) Next, the belt mounting jig 206 according to the second embodiment will be described with reference to Figures 16 to 19. The belt mounting jig 206 according to the second embodiment differs from the belt mounting jig 6 according to the first embodiment in that the relationship between the diameters of the second arc AR2 and the third arc AR3 is different. Note that components similar to those in the first embodiment are denoted by the same or corresponding reference numerals, and detailed descriptions may be omitted.

[0083] As shown in Figures 16 to 18, in the belt mounting jig 206 according to the second embodiment, the belt pressing portion 62 has a shape that follows the first arc AR1. The pulley pressing portion 61 has a shape that follows the second arc AR2, which is concentric with the center ARO of the first arc AR1. The connecting portion 65 has a shape that follows the third arc AR3, which is concentric with the center ARO of the first arc AR1.

[0084] In the second embodiment, the second arc AR2 is formed to have the same diameter as the third arc AR3. On the other hand, the first arc AR1 is formed to have a different diameter than the third arc AR3.

[0085] As shown in Figure 19, the belt mounting jig 206 of the second embodiment includes a first connecting portion 2614 that connects the connecting portion 65 and the pulley pressing portion 61. Unlike the first connecting portion 614 of the first embodiment, the first connecting portion 2614 does not have a first fold 611 and a second fold 612. In other words, the belt mounting jig 206 of the second embodiment is formed continuously from the connecting portion 65 to the pulley pressing portion 61 without any folds. Therefore, no steps are formed between the connecting portion 65 and the first connecting portion 2614, and between the first connecting portion 2614 and the pulley pressing portion 61.

[0086] Furthermore, the belt mounting jig 206 of the second embodiment also includes a second connecting portion 624 having a third fold 621 and a fourth fold 622, similar to the first embodiment. The second connecting portion 624 connects the coupling portion 65 and the belt retaining portion 62. Furthermore, the third fold 621 and fourth fold 622 formed on the second connecting portion 624 make it easier to hold the belt retaining portion 62 in a predetermined position relative to the connecting portion 65. Therefore, the pressing state of the V-ribbed belt 4 by the belt retaining portion 62 can be stabilized, and the rib displacement of the V-ribbed belt 4 can be suppressed.

[0087] In the second embodiment, since the second arc AR2 is formed to have the same diameter as the third arc AR3, the surface of the portion from the connecting portion 65 to the pulley pressing portion 61 that receives the load from the V-ribbed belt 4 can be formed smoothly. Therefore, when the V-ribbed belt 4 is placed on the pulley pressing portion 61, the load acting from the V-ribbed belt 4 on the belt mounting jig 206 can be easily distributed to the connecting portion 65 and the pulley pressing portion 61. Furthermore, because the surface from the connecting portion 65 to the pulley pressing portion 61 is smoothly formed, localized snagging is less likely to occur when the V-ribbed belt 4 moves on the pulley pressing portion 61. As a result, the V-ribbed belt 4 can be guided more smoothly.

[0088] As a result, the belt mounting jig 206 according to the second embodiment can suppress the increase in localized stress between the connecting portion 65 and the pulley pressing portion 61. This allows the V-ribbed belt 4 to be stably wrapped around the crank pulley 2 while suppressing deformation and looseness of the belt mounting jig 106.

[0089] Furthermore, in this embodiment, the diameter of the second arc AR2 (diameter E shown in Figure 18) is equal to the diameter of the third arc AR3 (diameter F shown in Figure 18) and is set to be larger than the diameter of the first arc AR1 (diameter D shown in Figure 18). As a result, a radial positional difference is formed between the belt retaining portion 62 and the pulley pressing portion 61 and the connecting portion 65. Furthermore, the diameter (diameter E) of the second arc AR2 may be set to be smaller than the diameter (diameter D) of the first arc AR1. Even in this case, a radial positional difference can be formed between the first arc AR1 and the second arc AR2. Therefore, a path can be formed to guide the V-ribbed belt 4, which is held down by the belt retaining portion 62, to the pulley pressing portion 61 via the belt insertion hole 63.

[0090] As a result, in the belt mounting jig 206 according to the second embodiment, it is possible to achieve both the pressing of the V-ribbed belt 4 by the belt pressing portion 62 and the guiding of the V-ribbed belt 4 by the pulley pressing portion 61. As a result, the V-ribbed belt 4, which is pressed by the belt pressing portion 62, can be smoothly guided to the belt holding portion 64. [Examples]

[0091] Next, belt mounting jigs (hereinafter referred to as "each test specimen") according to the examples and comparative examples were fabricated and belt mounting tests were conducted to compare and verify whether the belt could be easily attached to the pulley while preventing damage to the belt during attachment. The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0092] [Belt mounting jig] In the examples and comparative examples, central angles A, B, and C were modified as shown in Tables 1 to 5, respectively. Furthermore, in the test specimen corresponding to the first embodiment, a first fold and a second fold were formed in the first connecting portion that connects the connecting portion and the pulley pressing portion. On the other hand, in the test specimen corresponding to the second embodiment, the first and second folds were not formed in the first connecting portion, and the portion from the connecting portion to the pulley pressing portion was formed as a continuous flat portion. Furthermore, in all test specimens, a third fold and a fourth fold were formed in the second connecting portion that connects the connecting portion and the belt retaining portion. Other configurations were common, and the following conditions were also common.

[0093] Material: Made by press-forming hot-rolled mild steel sheet (SPHC, tensile yield strength 270 MPa). Plate thickness: 1.6mm Radius of curvature (inner diameter) of the connecting section: 72 mm Furthermore, in Examples 2 and 3, the step difference between the connecting portion and the pulley pressing portion of the first connection (radial length H of the first connection) was set to 6.1 mm. In the embodiments and comparative examples where a step was provided in the second connection portion, the step between the connecting portion and the belt retaining portion of the second connection portion (radial length I of the second connection portion) was set to 4.1 mm.

[0094] [V-ribbed belt] A V-ribbed belt with the following specifications was used: size designation: 4PJ864, number of ribs: 4, belt shape: J-shape, thickness: 3.8 mm, width: 9.4 mm, circumference: 864 mm.

[0095] [Evaluation of belt mounting fixture (belt mounting test)] For each of the test specimens in Examples 1-22 and Comparative Examples 1-6, in order to determine whether a belt mounting jig capable of solving the problem of the present invention was obtained, a belt mounting test was conducted using each test specimen as a mounting jig for attaching a V-ribbed belt to an auxiliary drive unit consisting of a two-axis layout of a crank pulley and an alternator pulley, as shown in Figure 1. The ease of mounting, load on the belt (presence or absence of damage due to deflection), load on the mounting jig (belt mounting jig), and rib slippage were verified. In the belt mounting test, each of 10 workers performed the mounting work once for evaluation.

[0096] [Ease of installation] (Evaluation method) In the belt attachment test, we measured whether the belt could be attached and the time taken for the work (average value by 10 workers), and evaluated it according to the following criteria. The attachment time was expressed as a relative value with the work time in Example 1 set to 1.00, and a rating of B or higher was considered acceptable from the perspective of whether it would be acceptable in actual use for this application.

[0097] (Judgment criteria) A rating: Belt can be attached, and the attachment time (relative value) is 1.00 or less. B rating: Belt can be attached, and the attachment time (relative value) exceeds 1.00. C rating: Belt installation was not possible.

[0098] [Load on the belt] (Evaluation method) After performing 10 belt installation tests, the belts were visually inspected to verify that there was no damage (ring breakage). Based on the criteria for acceptance in actual use for this application, i.e., the absence of damage due to deflection, a rating of "a" was given as a pass.

[0099] (Judgment criteria) A rating: If the belt is undamaged. C rating: If the belt is damaged.

[0100] [Load on mounting fixture] (Evaluation method) After one belt mounting operation and again after ten mounting operations in the belt mounting test, the radius of curvature of the belt mounting jig was measured using a contour shape measuring instrument (Mitutoyo Corporation Contrace CV3000). By reading the amount of deformation of the radius of curvature, it was verified whether the belt mounting jig deformed during the mounting operation. From the perspective of acceptance in actual use for this application, a rating of B or higher was considered acceptable.

[0101] (Judgment criteria) A rating: If the deformation of the radius of curvature is less than 1.0 mm after both one installation and ten installations. Grade b: The deformation of the radius of curvature is less than 1.0 mm after one installation, but the deformation is 1.0 mm or more after 10 installations. C rating: If the deformation of the radius of curvature after one installation operation is 1.0 mm or more.

[0102] [Rib shearing] (Evaluation method) After performing 10 belt mounting operations in the belt mounting test, the presence or absence of rib misalignment was visually verified. From the perspective of whether it is acceptable for actual use in this application, a rating of B or higher was considered a pass.

[0103] (Judgment criteria) A rating: If no rib misalignment occurred during 10 installation attempts. Grade B: Rib misalignment occurs only once in 10 installation attempts (rib misalignment occurs rarely). C rating: If rib misalignment occurs 2 or more times in 10 installation attempts (if rib misalignment occurs frequently).

[0104] [Overall assessment] Based on the evaluation of each evaluation item, an overall evaluation was conducted according to the following criteria. A Rank: When all evaluation items receive an "A" rating. Rank B: There are no C ratings in any of the evaluation items, but there is one B rating. C rank: No C rating in any evaluation item, but two or more B ratings. Rank D: If at least one evaluation item receives a "c" rating.

[0105] [Verification Results and Discussion] The verification results are shown in Tables 1-5.

[0106] <Table 1: Examples of changes in the presence or absence of folds at the first and second connection points> [Table 1]

[0107] (Examples 1-4) This is an example of changing the presence or absence of folds in the first connection part (first fold, second fold) and the second connection part (third fold, fourth fold). Focusing on each evaluation item, the load on the mounting jig was related to the presence or absence of folds in the first connection part. Examples 2 and 3, where the first connection part had folds, received a rating of b, while Examples 1 and 4, where the first connection part was flat without folds, received a rating of a. On the other hand, the rib slippage was related to the presence or absence of folds in the second connection part. Examples 1 and 2, where the second connection part had folds, received a rating of a, while Examples 3 and 4, where the first connection part was flat without folds, received a rating of b. Therefore, Example 1, where the first connection part is foldless and the second connection part has folds, was found to be preferable from the viewpoint of achieving an excellent balance between load on the mounting jig and rib slippage. On the other hand, Examples 2 to 4 also achieved a practically acceptable level (rank C or higher).

[0108] <Table 2: Examples based on Example 1, where central angle B and the sum of central angles A, B, and C are changed> [Table 2]

[0109] (Comparative Example 1, Examples 5-7, 1, 8-9, Comparative Example 2) This example is based on Example 1, but with a variation in the central angle B. As the central angle B was increased from 15° (Comparative Example 1), 18° (Example 5), 20° (Example 6), 25° (Example 7), to 30° (Example 1), there was a tendency for improvement in all evaluation items: ease of installation, load on the belt, load on the mounting jig, and rib slippage. Specifically, Comparative Example 1, with a central angle B of 15°, failed all evaluation items and received a D rank, while Example 5, with a central angle B of 18°, achieved a passing level (b or higher) in all evaluation items and received a passing grade (C rank). Furthermore, Example 6, with an even larger central angle B, received a B rank, and Examples 7 and 1 improved to an a rating in all evaluation items, resulting in an overall A rank. On the other hand, with the central angle B being 30° in Example 1, as the central angle B increased, the sum of central angles A, B, and C (A+B+C) increased compared to Example 1 where the sum was 65°, resulting in a tendency for the ease of installation to decrease. While the sums of 75° (Example 8) and 90° (Example 9) were at a practically acceptable level (B rank or higher), in Comparative Example 2, where the sum was 100°, it became impossible to install the belt by rotating the pulley while the belt was diagonally hooked onto the belt holding part (set state), resulting in a D rank (failure) from the perspective of ease of installation (impossible to install).

[0110] (Comparative Examples 3 and 4) In Example 8, the central angle A or C was increased by 25° to make the sum of the central angles 100°, the same as in Comparative Example 2. However, as with Comparative Example 2, belt attachment was not possible, resulting in a D rank (failure).

[0111] (Comparative Examples 5 and 6) In this example, the central angle A or C was increased by 15° from Comparative Example 1, but the results were the same as in Comparative Example 1 (rank D). In Comparative Examples 1, 5, and 6, the central angle B of the belt insertion hole was small, and the length of the part from where the belt is inserted from below the belt retaining part into the belt insertion hole and rides up onto the pulley pressing part was short. As a result, the deflection deformation of the belt in the set state was large, and it is thought that the belt was damaged when it was forcibly installed in a state of large deflection deformation. Furthermore, forcibly installing the belt in an unstable state with large deflection deformation also placed a large load on the installation jig, and as a result the installation work became difficult, and the workability of installation and rib slippage were also at a low level, which is thought to be the reason why all evaluation items were judged as C.

[0112] (Summary of Table 2) If the central angle B is less than 18°, damage due to belt deflection cannot be prevented. On the other hand, if the sum of the central angles exceeds 90°, belt installation becomes impossible. Therefore, when the central angle B is 18° or greater and the sum of the central angles is 90° or less, the problem of this invention is solved, and it was confirmed that the belt can be easily installed on the pulley while preventing damage to the belt during installation.

[0113] <Table 3: Example of changing the central angle A based on Example 1> [Table 3]

[0114] (Examples 10-14) This example is based on Example 1, but with the central angle A varied. As the central angle A increased from 10° (Example 10), 15° (Example 11), 18° (Example 12), to 20° (Example 1), there was a tendency for installation workability, load on the mounting jig, and rib misalignment to improve. On the other hand, with Example 1 at a central angle A of 20° as the boundary, as the central angle A increased to 30° (Example 13) and 35° (Example 14), there was a tendency for installation workability to decrease. In particular, Examples 12, 1, and 13, where the central angle A was 18° or greater and the sum of the central angles was 75° or less, received an "a" rating (overall rating A rank) in all evaluation items. From these results, it is considered that when the central angle A is less than 18°, the balance in the set state is poor, and the pressing force of the belt on the belt mounting jig is concentrated, increasing the load on the belt mounting jig. On the other hand, by setting the central angle A to 18° or more, the balance in the set state can be improved, and the load on the belt mounting jig can be reduced. Conversely, when the central angle A is made too large and the sum of the central angles exceeds 75°, it is considered that the weight of the belt mounting jig increases, and the ease of installation decreases. Therefore, it can be said that a high level of both ease of installation and load on the mounting jig can be achieved when the central angle A is 18° or more and the sum of the central angles is 75° or less.

[0115] <Table 4: Example of changing the central angle C based on Example 1> [Table 4]

[0116] (Examples 15-19) This example is based on Example 1, but with the central angle C varied. As the central angle C increased from 10° (Example 15), 12° (Example 16), to 15° (Example 1), there was a tendency for the rib slippage to improve. On the other hand, with Example 1 at a central angle C of 15° as the boundary, as the central angle C increased from 20° (Example 17), 25° (Example 18), to 30° (Example 19), there was a tendency for the ease of installation to decrease. In particular, Examples 16, 1, 17, and 18, where the central angle C was 12° or greater and the sum of the central angles was 75° or less, received an "a" rating (overall rating A rank) in all evaluation items. From these results, it is considered that when the central angle C is less than 12°, the pressing force at the point where the belt rib and pulley rib meet at the belt clamping part in the set state is slightly weaker, making rib slippage more likely. On the other hand, by setting the central angle C to 12° or more, the pressing force at the point where the belt rib and pulley rib meet at the belt clamping part can be secured, thus preventing rib slippage. Conversely, when the central angle C is made too large and the sum of the central angles exceeds 75°, it is considered that the weight of the belt mounting jig increases, reducing the ease of mounting. Therefore, it can be said that when the central angle C is 12° or more and the sum of the central angles is 75° or less, a high level of both ease of mounting and rib slippage prevention can be achieved.

[0117] <Table 5: An example of changing central angles A and C based on Example 5> [Table 5]

[0118] (Examples 20-22) This example is based on Example 5, where central angle B is at its lower limit (18°), and explores the relationship with the problem by varying central angles A and C. Example 20 is an example where both central angles A and C are reduced to 10°, but like Example 5, it achieved a passing level (b or higher) in each evaluation item and a passing level (C rank) in the overall evaluation. Examples 21 and 22 are examples where central angles A and C are increased, so that central angle B is at its lower limit (18°) and the sum of central angles is at its upper limit (90°), but like Example 5, it achieved a passing level (b or higher) in each evaluation item and a passing level (C rank) in the overall evaluation. Therefore, in these Examples 20 to 22, the effects of the present invention were obtained, and it was confirmed that the belt can be easily attached to the pulley while preventing damage to the belt during belt attachment.

[0119] <Stress analysis using the 3D finite element method (FEM)> To examine the differences between Examples 1 and 2, a three-dimensional finite element method (FEM) analysis was performed using the following method.

[0120] (Analysis method) A three-dimensional model of the shape of each specimen was created using analysis software (CATIA, manufactured by Dassault Systèmes). As shown in Figure 10(B), the maximum value of the stress (Mises stress) generated in the belt mounting fixture when a load is applied that causes the belt to press against the fixture in the diagonally placed portion was analyzed. The analysis conditions were as follows. Load applied: 1170N (Actual maximum load applied to the belt during installation) Material: Iron (Young's modulus 2.11 GPa, Poisson's ratio 0.291, density 7870 kg / m³) 3 ) Restricted parts: The pulley pressing part is fully restricted, while the first, second, and third contact parts are partially restricted only in the direction of contact with the pulley.

[0121] (Consideration based on stress analysis) The results of the stress analysis using FEM are shown in Figures 20 and 21. In the configuration of the belt mounting jig 6 of Embodiment 2 shown in Figure 20(A), as shown in Figure 20(B), the pressure exerted by the V-ribbed belt 4 against the belt mounting jig 6 in the set state is locally concentrated near the boundary between the pulley pressing portion 61 and the first connecting portion 614. On the other hand, in the configuration of the belt mounting jig 206 of Embodiment 1 shown in Figure 21(A), as shown in Figure 21(B), the pressure exerted by the V-ribbed belt 4 on the belt mounting jig 206 in the set state is distributed across the pulley pressing portion 61 and the first connecting portion 2614. Furthermore, the maximum Mises stress at the point where the V-ribbed belt 4 rides over was 200 MPa in Example 2, while it was significantly lower at 8 MPa in Example 1. In other words, compared to the belt mounting jig 6 of Embodiment 2, which has a first connection portion 2614 with a flat configuration, the belt mounting jig 206 of Embodiment 1 can distribute the stress acting from the V-ribbed belt 4 over a wider area when set, thus reducing the load on the belt mounting jig 206.

[0122] (Effects obtained) From the above verification results, it was confirmed that a belt mounting jig in which central angle B is 18° or more, and the sum of the angles of central angles A, B, and C is 90° or less, can suppress excessive deflection deformation of the belt when attaching the belt to the pulley, and can also suppress an excessive increase in tension required when putting the belt on the belt holding part. Therefore, it is possible to easily attach the belt while preventing damage to it. Furthermore, it was confirmed that when central angle A is 18° or greater, central angle C is 12° or greater, and the sum of the angles of central angles A, B, and C is 75° or less, a high level of balance can be achieved in terms of ease of installation, load on the belt, load on the belt mounting jig, and rib slippage. Furthermore, it was confirmed that by making the first connecting portion 2614 a flat structure and forming the portion from the connecting portion 65 to the pulley pressing portion 61 as a continuous surface, the stress acting on the belt mounting jig can be distributed, thereby further reducing the load on the belt mounting jig. On the other hand, it was confirmed that rib misalignment can be further suppressed in a configuration in which a third fold 621 and a fourth fold 622 are formed in the second connecting portion 624. Therefore, the configuration in which the first connecting portion 2614 is flat and the second connecting portion 624 has a third fold 621 and a fourth fold 622 is a suitable configuration that can balance ease of installation, load on the belt, load on the belt mounting jig, and rib slippage. [Explanation of Symbols]

[0123] 1. Auxiliary drive unit 2. Crank pulley (first pulley) 2a Pulley groove 2b Pulley flange 2c, 2d side 3 Alternator pulley 4 V-ribbed belt 4a Part 1 4b 2nd part 4c 3rd part 5 Boss Section 6. Belt mounting jig 61 Pulley pressing section 616 Second contact part 62 Belt retaining part 63 Belt insertion holes 64 Belt holding part 641 Folded section 642 Third contact part 65 Connecting part 651 1st contact part 611 First fold 612 Second fold 614 First connection section 621 Third fold 622 Fourth fold 624 Second connection section 13 wrench 206 Belt mounting jig 2614 First connection section ARO-centered AR1 First arc AR2 Second Arc AR3 Third Arc A. Center angle of the pulley pressing portion B. Center angle of the belt insertion hole C. Center angle of the belt retaining part DC rotational axis

Claims

1. A belt mounting jig is used when winding a circumferentially expandable belt, which is wound around multiple pulleys with fixed inter-axis distances from each other, except for one pulley, onto the remaining pulley, the first pulley, and is installed on the outer circumference of the first pulley. A belt retaining portion shaped along the first arc, A pulley pressing portion having a shape along a second arc concentric with the center of the first arc, A belt holding portion extending toward the inside of the first arc, A connecting portion that connects the belt retaining portion, the pulley pressing portion, and the belt holding portion in that order, having a shape along a third arc concentric with the center of the first arc, It has, In the connection direction of the aforementioned connecting portion, a belt insertion hole is formed between the belt retaining portion and the pulley pressing portion. When the central angle of the belt retaining portion is central angle C, the central angle of the belt insertion hole is central angle B, and the central angle of the pulley pressing portion is central angle A, A belt mounting jig characterized in that the central angle A is 18° or more, the central angle B is 18° or more, the central angle C is 12° or more, and the sum of the angles of the central angles A, B, and C is 90° or less.

2. The first arc is installed on the outer circumference of the first pulley such that its center lies on the axis of the first pulley. The belt mounting jig according to claim 1, characterized in that, when the belt is wound around the first pulley, the belt retaining portion presses the first portion of the belt against the outer circumferential surface of the first pulley, the pulley pressing portion is pressed against the outer circumferential surface of the first pulley by the second portion of the belt, and the belt holding portion hooks and holds the third portion of the belt.

3. The belt mounting jig according to claim 1, characterized in that the sum of the angles of central angle A, central angle B, and central angle C is 75° or less.

4. The belt mounting jig according to any one of claims 1 to 3, characterized in that the second arc has the same diameter as the third arc, and the first arc has a different diameter from the third arc.

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