Pulley and belt mounting jig set and belt mounting method

Abstract

This invention provides a belt mounting jig that minimizes belt deflection during belt attachment to pulleys, thereby preventing belt damage and enabling easy belt installation. [Solution] The belt mounting jig 6 comprises a pulley pressing portion 61 which is pressed against the outer circumference of the pulley 2 by the tension of the diagonally hung V-ribbed belt 4, a belt retaining portion 62 which presses the V-ribbed belt 4 against the outer circumference of the pulley 2, a belt insertion hole 63 provided between the pulley pressing portion 61 and the belt retaining portion 62, and a belt holding portion 64 which hooks and holds the portion of the V-ribbed belt 4 that is off the outer circumference of the pulley 2, and the sum of the central angle A from the boundary 619 between the pulley pressing portion 61 and the belt insertion hole 63 to the belt holding portion 64, the central angle B of the belt insertion hole 63 and the central angle C of the belt retaining portion 62, with the rotation center DC of the pulley 2 as the center, is 90° or less, and the central angle B is 18° or more.

Description

Technical Field

[0001] The present invention relates to a belt mounting jig that is installed on the outer periphery of a pulley for winding a belt around the pulley.

Background Art

[0002] In a belt transmission mechanism, for example, there is a layout in which the axial distances between a plurality of pulleys to be mounted are all fixed and no tension applying mechanisms such as a tension pulley and a tensioner are used. In such a belt transmission mechanism layout, in order to reliably transmit power between the pulleys, the belt circumference is made shorter than the layout circumference between the plurality of pulleys to be mounted, so that a strong tension is applied to the belt.

[0003] As a method of attaching a belt having a circumference shorter than the layout circumference between such a plurality of pulleys, for example, the following method is used. First, leaving one pulley last, the belt is first wound around the other pulleys. Next, using a belt mounting jig, while applying tension to the belt wound around the other pulleys, the belt is attached to the outer peripheral surface of the last remaining pulley while rotating the last remaining pulley.

[0004] As a belt mounting jig used for such a belt mounting method, Patent Document 1 discloses a belt mounting jig including a pulley pressing portion that is pressed against the outer periphery of the pulley by the tension of the belt when the belt is hung, a belt holding portion that hooks and holds the belt, and a belt pressing portion that presses the belt against the outer periphery of the pulley. According to this configuration, by rotating the pulley while the belt pressing portion keeps the belt along the outer periphery of the pulley, the belt hooked by the belt holding portion moves to the pulley, and the belt can be easily attached to the pulley.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, when attaching a belt using the belt attachment jig described in Patent Document 1, the belt is pressed against the belt retaining portion and then diagonally hooked onto the belt holding portion. As a result, the portion of the belt from below the belt retaining portion to where it rides up onto the pulley pressing portion deflects outward in the pulley radial direction. Forcing the belt into place while this deflection is present can damage the belt and reduce its durability.

[0007] Furthermore, with the increasing diversification of belt drive mechanisms in recent years, pulley layouts have become more diverse, and consequently, the shapes of belt mounting fixtures have also become more varied. On the other hand, design methods for belt mounting fixtures that minimize belt deflection have not been clearly established until now.

[0008] Therefore, the object of the present invention is to provide a belt mounting jig that allows for easy belt installation while preventing damage to the belt by minimizing belt deflection when attaching the belt to the pulley. [Means for solving the problem]

[0009] 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 to wrap a belt, which is wrapped around at least one pulley, around a first pulley different from the at least one pulley, A pulley pressing portion is positioned on the outer circumference of the first pulley, and a portion of the belt is placed diagonally with respect to the circumferential direction of the first pulley, and is pressed against the outer circumference of the first pulley by the tension of the belt; A belt retainer is positioned on the outer circumference of the first pulley and presses the portion of the belt that runs along the outer circumference of the first pulley against the outer circumference of the first pulley. A belt insertion hole is provided on the outer circumference of the first pulley, between the pulley pressing portion and the belt retaining portion, through which the belt is inserted, A belt holding portion is positioned in the circumferential direction of the first pulley, at a position further from the belt holding portion than the boundary between the pulley pressing portion and the belt insertion hole, and hooks and holds the portion of the belt that is off the outer circumference of the first pulley. Equipped with, With the belt mounting jig installed on the outer circumference of the first pulley, The central angle A is defined as the central angle from the boundary between the pulley pressing portion and the belt insertion hole to the belt holding portion, with respect to the rotation center of the first pulley. Let the central angle of the belt insertion hole of the first pulley, centered on the rotation center, be the central angle B. When the central angle of the belt retaining portion with respect to the rotation center of the first pulley is defined as the central angle C, The central angle B is 18° or greater, and the sum of the central angles A, B, and C is 90° or less.

[0010] With one portion of the belt pressed against the outer circumference of the first pulley by the belt retainer, the other portion is pulled out radially outward from the first pulley through the belt insertion hole adjacent to the belt retainer, rides up onto the pulley pressing portion, and is then diagonally hooked onto the belt holding portion. By rotating the first pulley in this state, the belt hooked onto the belt holding portion moves onto the first pulley, and the belt is attached to the first pulley. If the central angle B of the belt insertion hole is less than 18°, the length of the belt from below the belt retaining portion to where it rides up onto the pulley pressing portion is short, causing a large radial outward deflection and deformation in this portion. When the belt is wrapped around the first pulley in this state of significant deflection, there is a risk of the belt being damaged. Furthermore, if the sum of the central angle A from the boundary between the pulley pressing portion and the belt insertion hole to the belt holding portion, the central angle B of the belt insertion hole, and the central angle C of the belt retaining portion exceeds 90°, the tension of the belt becomes too great when the belt, which is partially pressed against the belt retaining portion, is diagonally hooked onto the belt holding portion. This makes it difficult, or even impossible, to wrap the belt around the first pulley. Therefore, by setting the central angle B of the belt insertion hole to 18° or more, it is possible to suppress the large radial outward deflection deformation of the belt from below the belt retaining portion to where it rides up onto the pulley pressing portion. As a result, it is possible to prevent damage to the belt that occurs when the belt is wrapped around the first pulley in a greatly deflected state. Furthermore, by making the sum of the central angle A from the boundary between the pulley pressing portion and the belt insertion hole to the belt holding portion, the central angle B of the belt insertion hole, and the central angle C of the belt retaining portion 90° or less, the tension of the belt when the belt, which is partially pressed against the belt retaining portion, is diagonally hooked onto the belt holding portion can be reduced to a degree that allows the belt to be wrapped around the first pulley with some slack. Therefore, the belt mounting jig allows for easy attachment of the belt to the first pulley while preventing damage to the belt during installation.

[0011] Furthermore, the belt mounting jig of the present invention is The central angle A may also be characterized by being 18° or greater.

[0012] If the central angle A from the boundary between the pulley pressing portion and the belt insertion hole to the belt holding portion is less than 18°, the pressing force of the belt will be concentrated on the belt holding portion. As a result, when the belt moves away from the belt holding portion to the outer circumference of the first pulley, the belt may not move smoothly to the outer circumference of the first pulley, and the belt may slip on the outer circumference of the first pulley. In addition, the concentrated pressing force of the belt on the belt holding portion may cause deformation of the belt mounting jig. Therefore, by setting the central angle A to 18° or more, the pressing force of the belt on the belt mounting jig is distributed, and the pressing force of the belt on the belt holding part is reduced. As a result, the belt moves smoothly away from the belt holding part onto the outer circumference of the first pulley, preventing the belt from slipping on the outer circumference of the first pulley. In addition, the reduction in the pressing force of the belt on the belt holding part prevents deformation of the belt mounting jig.

[0013] Furthermore, the belt mounting jig of the present invention is The central angle C may also be characterized by being 12° or greater.

[0014] If the central angle C of the belt retainer is less than 12°, the area on which the belt retainer presses against the belt is insufficient. As a result, when wrapping the belt around the first pulley, the belt is more likely to lift away from the outer circumference of the first pulley, and the belt may slip around the outer circumference of the first pulley. Therefore, by making the central angle C of the belt retainer 12° or more, the area over which the belt retainer presses against the belt can be increased to the extent that the belt does not lift up from the outer circumference of the first pulley when the belt is wrapped around the first pulley. As a result, it is possible to prevent the belt from slipping around the outer circumference of the first pulley.

[0015] Furthermore, the belt mounting jig of the present invention is The property may also be characterized in that the sum of the central angles A, B, and C is 75° or less.

[0016] By making the sum of the central angle A from the boundary between the pulley pressing portion and the belt insertion hole to the belt holding portion, the central angle B of the belt insertion hole, and the central angle C of the belt retaining portion 75° or less, it is possible to make the belt mounting jig compact while ensuring that the belt retaining portion presses the belt along the outer circumference of the first pulley without lifting off the first pulley.

[0017] Furthermore, the belt mounting jig of the present invention is A connecting portion that is disposed at a position deviated from the outer periphery of the first pulley and connects the pulley pressing portion and the belt pressing portion. A first connecting portion that connects the connecting portion and the pulley pressing portion. A second connecting portion that connects the connecting portion and the belt pressing portion. Comprising: In the connection of the first connecting portion with the connecting portion and the pulley pressing portion, it is flat along the outer periphery of the first pulley without a fold from the connecting portion to the pulley pressing portion without passing through a fold. The second connecting portion may be characterized by having a third fold bent radially inward of the first pulley from the connecting portion and a fourth fold bent radially outward of the first pulley from the belt pressing portion.

[0018] The first connecting portion is formed so as not to pass through a fold in the connection with the connecting portion and the pulley pressing portion. And the belt mounting jig is formed flat along the outer periphery of the first pulley without a fold from the connecting portion to the pulley pressing portion. Therefore, in a state where the belt is obliquely hung on the pulley pressing portion, the pressing force acting on the belt mounting jig from the belt is easily dispersed over the connecting portion, the first connecting portion, and the pulley pressing portion. As a result, compared with the case where the first connecting portion is connected to the connecting portion and the pulley pressing portion via a fold, has a fold in the middle from the connecting portion to the pulley pressing portion of the belt mounting jig, and a step is formed between the connecting portion and the pulley pressing portion by the fold, local concentration of stress acting on the belt mounting jig from the belt is suppressed, and an increase in local stress generated in the belt and the belt mounting jig and rattling due to inclination of the belt mounting jig caused thereby can be suppressed. Furthermore, the second connecting portion has a third fold bent radially inward from the connecting portion toward the first pulley, and a fourth fold bent radially outward from the belt retaining portion toward the first pulley. As a result, the belt retaining portion can press the belt from the upper side of the belt so that it follows the outer circumference of the first pulley without lifting away from it, thereby suppressing the occurrence of so-called rib misalignment, where the belt shifts away from the first pulley, during belt installation. This reduces the load on the belt and belt mounting jig, stabilizes the belt's positioning, and improves the workability when attaching the belt to the first pulley. [Brief explanation of the drawing]

[0019] [Figure 1] This is a partial perspective view of the auxiliary drive unit around which the belt is wrapped using a belt mounting jig. [Figure 2] This diagram illustrates the structure of the crank pulley in the auxiliary drive unit shown in Figure 1. [Figure 3] This is a perspective view of the belt mounting jig according to the first embodiment. [Figure 4] This is a six-view drawing of a belt mounting jig according to the first embodiment. [Figure 5] This is a side view of the belt mounting 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 side 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]

[0020] (First Embodiment) Hereinafter, with reference to the drawings, the belt mounting jig 6 according to the first embodiment will be explained as an example of its use in an auxiliary drive unit 1 of an automobile engine, where it is installed on the outer circumference of the crank pulley 2 to wrap around the V-ribbed belt 4 that is wrapped around the alternator pulley 3 around the crank pulley 2. Furthermore, the explanation of the components of the belt mounting jig 6 will be based on the positional relationship when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2.

[0021] Furthermore, the belt mounting jig 6 according to the first embodiment may be used to wrap a belt that is already wrapped around two or more pulleys around another pulley. Furthermore, the use of the belt mounting jig 6 is not particularly limited. 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.

[0022] (Crank pulley 2, alternator pulley 3) 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, shown by solid and dashed lines, is wrapped around the crank pulley 2 and the alternator pulley 3. As a result, the power from the crankshaft is transmitted to the alternator's input shaft via the crank pulley 2, the V-ribbed belt 4, and the alternator pulley 3 in that order. In the first embodiment, 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 that applies tension to the V-ribbed belt 4.

[0023] 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. In the following explanation, the center of the rotation axis of the crank pulley 2 will be referred to as the rotation center DC of the crank pulley 2. Also, the radial direction of the crank pulley 2 will simply be referred to as the radial direction, with the side of the radial rotation center DC being called the radial inner side and the side opposite the radial rotation center DC being called the radial outer side. Furthermore, in the following explanation, the width direction of the crank pulley 2 is the direction parallel to the rotation center DC of the crank pulley 2.

[0024] (V-ribbed belt 4) The V-ribbed belt 4 is a so-called low-modulus belt that is slightly stretchable in its circumferential direction. Low-modulus belts have a relatively low modulus of elasticity due to the use of polyamide fibers in the core wire, and compared to high-modulus belts with a high modulus of elasticity, a rapid decrease in tension is suppressed. In the first embodiment, 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 belt circumferential direction. The layout circumference refers to the length of a line formed in an annular shape along the outer circumference to connect the outer circumferences of each pulley in two or more pulleys (corresponding to the pulley layout circumference).

[0025] 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.

[0026] (Belt mounting jig 6) As shown in Figures 3 to 8, the belt mounting jig 6 is positioned on the outer circumference of the crank pulley 2 and includes a pulley pressing portion 61 on which a part of the V-ribbed belt 4 is hung diagonally with respect to the circumferential direction of the crank pulley 2 and pressed against the outer circumference of the crank pulley 2 by the tension of the V-ribbed belt 4; a belt retaining portion 62 positioned on the outer circumference of the crank pulley 2 and pressing the portion of the V-ribbed belt 4 that is aligned with the outer circumference of the crank pulley 2 against the outer circumference of the crank pulley 2; a belt insertion hole 63 provided on the outer circumference of the crank pulley 2 between the pulley pressing portion 61 and the belt retaining portion 62, through which the V-ribbed belt 4 is inserted; and a belt holding portion 64 positioned in the circumferential direction of the crank pulley 2, further from the belt retaining portion 62 than the boundary 619 between the pulley pressing portion 61 and the belt insertion hole 63, and which hooks and holds the portion of the V-ribbed belt 4 that is off the outer circumference of the crank pulley 2.

[0027] The material and manufacturing method of the belt mounting jig 6 are not particularly limited; for example, it may be integrally formed from a steel plate by sheet metal processing.

[0028] (Connection part 65) The belt mounting jig 6 is positioned off the outer circumference of the crank pulley 2 and includes a connecting portion 65 that connects the pulley pressing portion 61, the belt retaining portion 62, and the belt holding portion 64. The connecting portion 65 connects the pulley pressing portion 61, the belt retaining portion 62, and the belt holding portion 64, making the belt mounting jig 6 an integrated unit. The belt holding portion 64 is connected to one end of the connecting portion 65 in the circumferential direction of the crank pulley 2. The connecting portion 65 has a first contact portion 651 formed by bending or curving the end opposite to the belt holding portion 64 radially inward in the circumferential direction of the crank pulley 2. 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 outer circumference of the crank pulley 2. The portion of the connecting portion 65 between the first contact portion 651 and the belt holding portion 64 is formed in an arc shape centered on the rotation center DC of the crank pulley 2.

[0029] (Pulley pressing portion 61) As shown in Figure 5, the pulley pressing portion 61 is formed in an arc shape centered on the rotation center DC of the crank pulley 2 when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2. Furthermore, the belt mounting jig 6 is equipped with a second contact portion 616 that extends radially inward from the pulley pressing portion 61 so as to face the side surface 2c of the crank pulley 2. Furthermore, as shown in Figure 6, the belt mounting jig 6 has a fold 611 (corresponding to the first fold) bent radially inward from the connecting portion 65 to the crank pulley 2, and a fold 612 (corresponding to the second fold) bent radially outward from the pulley pressing portion 61 to the crank pulley 2, and is equipped with a first connecting portion 614 that connects the connecting portion 65 and the pulley pressing portion 61. That is, the first connecting portion 614 is connected to the connecting portion 65 via the fold 611 and to the pulley pressing portion 61 via the fold 612. In addition, the belt mounting jig 6 has a fold 613 between the pulley pressing portion 61 and the second contact portion 616 bent radially inward from the pulley pressing portion 61 to the crank pulley 2. That is, the pulley pressing portion 61 is connected to the second contact portion 616 via the fold 613. The pulley pressing portion 61 is formed such that 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 outer circumference of the crank pulley 2.

[0030] Furthermore, in the first embodiment, as shown in Figure 5, when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2, and the central angle A is defined as the central angle from the boundary 619 between the pulley pressing portion 61 and the belt insertion hole 63 to the belt holding portion 64, with respect to the rotation center DC of the crank pulley 2, the central angle A is set to 20°. Furthermore, in the first embodiment, with the belt mounting jig 6 installed on the outer circumference of the crank pulley 2, the central angle of the pulley pressing portion 61, centered on the rotation center DC of the crank pulley 2, is set to 20°, the same as the central angle A. Note that the central angle of the pulley pressing portion 61 may be smaller than the central angle A. In the first embodiment, the central angle of the pulley pressing portion 61 is constant in the width direction of the crank pulley 2. However, the central angle of the pulley pressing portion 61 does not have to be constant in the width direction of the crank pulley 2. In the first embodiment, the central angle of the first connecting portion 614 is constant in the radial direction. However, the central angle of the first connecting portion 614 does not have to be constant in the radial direction. In the first embodiment, the central angle of the first connecting portion 614 is the same as the central angle of the pulley pressing portion 61. However, the central angle (maximum central angle) of the first connecting portion 614 of the pulley pressing portion 61 may be greater than the central angle (maximum central angle) of the pulley pressing portion 61. In the first embodiment, the central angle of the second contact portion 616 of the pulley pressing portion 61 is constant in the radial direction. However, the central angle of the second contact portion 616 of the pulley pressing portion 61 does not have to be constant in the radial direction. In the first embodiment, the central angle of the second contact portion 616 is the same as the central angle of the pulley pressing portion 61. However, the central angle (maximum central angle) of the second contact portion 616 may be smaller than the central angle (maximum central angle) of the pulley pressing portion 61.

[0031] (Belt holding part 62) As shown in Figure 5, the belt retaining portion 62 is formed in an arc shape centered on the rotation center DC of the crank pulley 2 when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2. Furthermore, as shown in Figure 6, the belt mounting jig 6 has a fold 621 (corresponding to the third fold) bent radially inward from the connecting portion 65, and a fold 622 (corresponding to the fourth fold) bent radially outward from the belt retaining portion 62 to the crank pulley 2, and is equipped with a second connecting portion 624 that connects the connecting portion 65 and the belt retaining portion 62. The belt mounting jig 6 may also include a fourth contact portion extending radially inward from the belt retaining portion 62 so as to face the side surface 2c of the crank pulley 2. In this case, the belt retaining portion 62 is formed such that the fourth contact portion contacts the side surface 2c of the crank pulley 2 when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2.

[0032] Furthermore, in the first embodiment, as shown in Figure 5, when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2, and the central angle of the belt retaining portion 62 with respect to the rotation center DC of the crank pulley 2 is defined as the central angle C, the central angle C is set to 15°. In the first embodiment, the central angle of the belt retaining portion 62 is constant in the width direction of the crank pulley 2. However, the central angle of the belt retaining portion 62 does not have to be constant in the width direction of the crank pulley 2. In the first embodiment, the central angle of the second connecting portion 624 is constant in the radial direction. However, the central angle of the second connecting portion 624 does not have to be constant in the radial direction. In the first embodiment, the central angle of the second connecting portion 624 is the same as the central angle of the belt retaining portion 62. However, the central angle (maximum central angle) of the second connecting portion 624 of the belt retaining portion 62 may be greater than the central angle (maximum central angle) of the belt retaining portion 62. If the belt mounting jig 6 has a fourth contact portion, the central angle of the fourth contact portion may be constant in the radial direction or not. The central angle (maximum central angle) of the fourth contact portion may be the same as the central angle (maximum central angle) of the belt retaining portion 62, or it may be smaller than the central angle (maximum central angle) of the belt retaining portion 62.

[0033] Furthermore, as shown in Figure 5, the distance D from the rotation center DC of the crank pulley 2 to the radially inner surface of the belt retainer 62 that contacts the V-ribbed belt 4 (corresponding to the first contact surface) is greater than the distance E from the rotation center DC of the crank pulley 2 to the radially outer surface of the pulley pressing portion 61 that contacts the V-ribbed belt 4 (corresponding to the second contact surface) by the thickness of the V-ribbed belt 4. This allows the pulley pressing portion 61 to be pressed against the outer circumference of the crank pulley 2 by the tension of the V-ribbed belt 4, while the belt retainer 62 presses the V-ribbed belt 4 against the outer circumference of the crank pulley 2. The thickness of the V-ribbed belt 4 here should be within the range from the minimum thickness of the V-ribbed belt 4 when it is attached to the crank pulley 2 by the belt mounting jig 6 to the thickness of the V-ribbed belt 4 when it is unloaded.

[0034] Furthermore, as shown in Figure 5, the radial distance F from the rotation center DC of the crank pulley 2 to the fold 611 is the same as the radial distance G from the rotation center DC of the crank pulley 2 to the fold 621. As shown in Figure 6, the radial length H of the first connecting portion 614 is greater than the radial length I of the second connecting portion 624 by the thickness of the V-ribbed belt 4. This allows the pulley pressing portion 61 to be pressed against the outer circumference of the crank pulley 2 by the tension of the V-ribbed belt 4, while the belt retaining portion 62 presses the V-ribbed belt 4 against the outer circumference of the crank pulley 2. The thickness of the V-ribbed belt 4 here should be within the range from the minimum thickness of the V-ribbed belt 4 when it is attached to the crank pulley 2 by the belt mounting jig 6 to the thickness of the V-ribbed belt 4 when it is unloaded.

[0035] Furthermore, the fold 611 of the first connecting portion 614 and the fold 621 of the second connecting portion 624 are located in the same position in the width direction of the crank pulley 2 when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2, as shown in Figure 4.

[0036] (Belt insertion hole 63) The belt insertion hole 63 is an arc-shaped space enclosed by the pulley pressing portion 61, the belt retaining portion 62, and the connecting portion 65. Furthermore, in the first embodiment, as shown in Figure 5, when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2, and the central angle of the belt insertion hole 63 with respect to the rotation center DC of the crank pulley 2 is defined as the central angle B, the central angle B is set to 27°.

[0037] (Belt holding part 64) The belt holding portion 64 is formed by bending radially inward from the end of the connecting portion 65 opposite to the first contact portion 651. Alternatively, the belt holding portion 64 may be formed by curving radially inward in an arc shape or a substantially arc shape from the end of the connecting portion 65 opposite to the first contact portion 651. As shown in Figure 9, the belt holding portion 64 has a convex fold 641 that is bent from the end of the connecting portion 65, and the V-ribbed belt 4 is hooked onto this fold 641. Furthermore, the end face of the belt holding portion 64 that faces the side surface 2d of the crank pulley 2 constitutes the third contact portion 642. 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 outer circumference of the crank pulley 2.

[0038] (First contact part 651, second contact part 616, third contact part 642) When the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2, the first contact portion 651 of the connecting portion 65 and the third contact portion 642 of the belt holding portion 64 contact the side surface 2d of the crank pulley 2, and the second contact portion 616 of the pulley pressing portion 61 contacts the side surface 2c of the crank pulley 2, so that the belt mounting jig 6 can clamp the crank pulley 2 from both sides in the width direction of the crank pulley 2. As a result, the belt mounting jig 6 can be installed without any misalignment in the width direction of the crank pulley 2. The configuration is not limited to the first embodiment; it is sufficient that at least one of the first contact portion 651 and the third contact portion 642 is formed, and at least one of the second contact portion 616 and the fourth contact portion is formed. In other words, the belt mounting jig 6 only needs to have at least one contact portion on each side in the width direction of the crank pulley 2.

[0039] (Central angle A, central angle B, central angle C, and their relationships) (1) In the belt mounting jig 6 of the above embodiment, as shown in Figure 5, the central angle A from the boundary 619 between the pulley pressing portion 61 and the belt insertion hole 63 to the belt holding portion 64 is 20°, the central angle B of the belt insertion hole 63 is 27°, and the central angle C of the belt retaining portion 62 is 15°. However, in the belt mounting jig 6, the values ​​of central angles A, B, and C are not limited to the above values, as long as central angle B is 18° or more, and the sum of central angles A, B, and C is 90° or less.

[0040] (2) Furthermore, in the belt mounting jig 6, it is preferable that the central angle A is 18° or more.

[0041] (3) Furthermore, in the belt mounting jig 6, it is preferable that the central angle C is 12° or more.

[0042] (4) Based on (1) to (3) above, since central angle A ≥ 18°, central angle B ≥ 18°, and central angle C ≥ 12°, central angle A + central angle B + central angle C ≥ 48°. Furthermore, since central angle A ≥ 18°, central angle C ≥ 12°, and central angle A + central angle B + central angle C ≤ 90°, central angle B ≤ 60°. Furthermore, since central angle B ≥ 18°, central angle C ≥ 12°, and central angle A + central angle B + central angle C ≤ 90°, central angle A ≤ 60°. Furthermore, since central angle A ≥ 18°, central angle B ≥ 18°, and central angle A + central angle B + central angle C ≤ 90°, central angle C ≤ 54°. As a result, 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°. As will be explained in more detail later, it is preferable for the sum of central angles A and B to be as large as possible. In this case, increasing central angle B will increase the sum of central angles A and B, so it is preferable for central angle B to be as large as possible.

[0043] In this regard, focusing solely on the viewpoint of suppressing large radial outward deflection deformation of the V-ribbed belt 4 from the radially inward position of the belt retaining portion 62 until it rides up onto the pulley pressing portion 61, it is preferable to maximize the central angle B. That is, a central angle A of 18°, a central angle C of 12°, and a central angle B of 60° are preferable from the viewpoint of suppressing deflection of the V-ribbed belt 4. However, from the perspective of suppressing deflection of the V-ribbed belt 4, preventing rib displacement of the V-ribbed belt 4, and ensuring 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°.

[0044] (5) Furthermore, in the belt mounting jig 6, it is preferable that the sum of central angle A, central angle B, and central angle C is 75° or less. By making the sum of central angles A, B, and C 75° or less, the belt mounting jig 6 can be made more compact while ensuring that the belt retaining portion 62 does not lift off the crank pulley 2 and that the V-ribbed belt 4 is pressed along the outer circumference of the crank pulley 2.

[0045] (6) Based on (1) to (3) and (5) above, since central angle A ≥ 18°, central angle B ≥ 18°, and central angle C ≥ 12°, central angle A + central angle B + central angle C ≥ 48°. Furthermore, since central angle A ≥ 18°, central angle C ≥ 12°, and central angle A + central angle B + central angle C ≤ 75°, we have central angle B ≤ 45°. Furthermore, since central angle B ≥ 18°, central angle C ≥ 12°, and central angle A + central angle B + central angle C ≤ 75°, central angle A ≤ 45°. Furthermore, since central angle A ≥ 18°, central angle B ≥ 18°, and central angle A + central angle B + central angle C ≤ 75°, central angle C ≤ 39°. As a result, the preferred ranges are 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°. As will be explained in more detail later, it is preferable for the sum of central angles A and B to be as large as possible. In this case, increasing central angle B will increase the sum of central angles A and B, so it is preferable for central angle B to be as large as possible.

[0046] In this regard, focusing solely on the viewpoint of suppressing large radial outward deflection deformation of the V-ribbed belt 4 from the radially inward position of the belt retaining portion 62 until it rides up onto the pulley pressing portion 61, it is preferable to maximize the central angle B. That is, a central angle A of 18°, a central angle C of 12°, and a central angle B of 45° are preferable from the viewpoint of suppressing deflection of the V-ribbed belt 4. However, from the perspective of suppressing deflection of the V-ribbed belt 4, preventing rib displacement of the V-ribbed belt 4, and ensuring 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°.

[0047] Furthermore, in the belt mounting jig 6, it is preferable that the central angle of the pulley pressing portion 61 is 18° or greater.

[0048] (How to use) Next, the method of using the belt mounting jig 6 of the first embodiment will be explained with reference to Figures 11 to 15.

[0049] (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.

[0050] (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 first contact portion 651 of the belt mounting jig 6 and the third contact portion 642 of the belt holding portion 64 are brought into contact with the side surface 2d of the crank pulley 2, and the second contact portion 616 of the pulley pressing portion 61 is brought into contact with the side surface 2c of the crank pulley 2, thereby clamping the belt mounting jig 6 to the crank pulley 2 from both sides in the width direction. This allows the belt mounting jig 6 to be held integrally with the crank pulley 2 so as to be able to rotate together. Next, as shown in Figures 9 and 11, the V-ribbed belt 4 is positioned such that a portion is pressed against the outer circumference of the crank pulley 2 by the belt retaining portion 62, and the other portion is pulled radially outward through the belt insertion hole 63 adjacent to the belt retaining portion 62. After riding up onto the pulley pressing portion 61, it is then hooked diagonally toward the belt holding portion 64.

[0051] Here, if the central angle B of the belt insertion hole 63 is less than 18°, the length of the portion of the V-ribbed belt 4 from the radially inward position of the belt retaining portion 62 to where it rides up onto the pulley pressing portion 61 is short, so as shown in Figure 10(A), this portion will deform significantly radially outward. When the V-ribbed belt 4 is wrapped around the crank pulley 2 in this state of significant deflection, there is a risk that the V-ribbed belt 4 may be damaged. Furthermore, if the sum of central angles A, B, and C exceeds 90°, the tension of the V-ribbed belt 4 becomes too great when the V-ribbed belt 4, which is partially pressed against the belt retaining portion 62, is diagonally hooked onto the belt holding portion 64. This makes it difficult to wrap the V-ribbed belt 4 around the crank pulley 2, or even impossible to wrap the V-ribbed belt 4 around the crank pulley 2. Therefore, by setting the central angle B to 18° or more, it is possible to suppress the large radial outward deflection deformation of the V-ribbed belt 4 from the radially inward position of the belt retaining portion 62 until it rides up onto the pulley pressing portion 61. As a result, it is possible to prevent damage to the V-ribbed belt 4 that occurs when the V-ribbed belt 4 is wrapped around the crank pulley 2 in a greatly deflected state. Furthermore, by making the sum of central angles A, B, and C 90° or less, the tension of the V-ribbed belt 4 when it is diagonally hooked onto the belt holding portion 64 while a portion of it is pressed against the belt retaining portion 62 can be reduced to a degree that allows the V-ribbed belt 4 to be wrapped around the crank pulley 2 with some slack.

[0052] Furthermore, if the central angle C is less than 12°, the area on which the belt retaining portion 62 presses against the V-ribbed belt 4 is insufficient. As a result, when wrapping the V-ribbed belt 4 around the crank pulley 2, the V-ribbed belt 4 tends to lift away from the outer circumference of the crank pulley 2, and the V-ribbed belt 4 may slip on the outer circumference of the crank pulley 2. Therefore, by setting the central angle C to 12° or more, the area over which the belt retainer 62 presses the V-ribbed belt 4 can be increased to the extent that it can suppress the V-ribbed belt 4 from lifting off the outer circumference of the crank pulley 2 when the V-ribbed belt 4 is wrapped around the crank pulley 2. As a result, it is possible to prevent rib slippage, which is a phenomenon in which the V-ribbed belt 4 slips on the outer circumference of the crank pulley 2.

[0053] Furthermore, if the difference between the distance D from the rotation center DC of the crank pulley 2 to the radially inner surface of the belt retaining portion 62 that contacts the V-ribbed belt 4, and the distance E from the rotation center DC of the crank pulley 2 to the radially outer surface of the pulley pressing portion 61 that contacts the V-ribbed belt 4 becomes smaller than the thickness of the V-ribbed belt 4, the pulley pressing portion 61 will not contact the outer circumference of the crank pulley 2 and will lift up, increasing the distance from the outer circumference of the crank pulley 2 to the radially outer surface of the pulley pressing portion 61. As a result, as shown in Figure 10(A), the radially outward deflection deformation of the portion of the V-ribbed belt 4 from the radially inner position of the belt retaining portion 62 to where it rides up onto the pulley pressing portion 61 will increase. On the other hand, if the difference between distance D and distance E becomes larger than the thickness of the V-ribbed belt 4, the belt retaining portion 62 will not be able to press the V-ribbed belt 4, and the V-ribbed belt 4 may slip on the outer circumference of the crank pulley 2. Therefore, by making the difference between distance D and distance E equal to the thickness of the V-ribbed belt 4, it is possible to suppress the deflection of the V-ribbed belt 4 while preventing the ribs of the V-ribbed belt 4 from shifting on the outer circumference of the crank pulley 2.

[0054] Furthermore, if the difference between the radial length H of the first connecting portion 614 and the radial length I of the second connecting portion 624 becomes smaller than the thickness of the V-ribbed belt 4, the pulley pressing portion 61 will not contact the outer circumference of the crank pulley 2 and will lift up. As a result, the distance from the outer circumference of the crank pulley 2 to the radially outer surface of the pulley pressing portion 61 will increase, and the radially outward deflection deformation will increase in the portion of the V-ribbed belt 4 from the radially inner position of the belt retaining portion 62 to where it rides up onto the pulley pressing portion 61. On the other hand, if the difference between the radial length H of the first connecting portion 614 and the radial length I of the second connecting portion 624 becomes larger than the thickness of the V-ribbed belt 4, the belt retaining portion 62 will not be able to press the V-ribbed belt 4, and the V-ribbed belt 4 may slip on the outer circumference of the crank pulley 2. Therefore, by making the difference between the radial length H of the first connecting portion 614 and the radial length I of the second connecting portion 624 equal to the thickness of the V-ribbed belt 4, it is possible to suppress the deflection of the V-ribbed belt 4 while preventing the V-ribbed belt 4 from shifting on the outer circumference of the crank pulley 2.

[0055] Furthermore, as shown in Figure 4, the fold 611 of the first connecting portion 614 and the fold 621 of the second connecting portion 624 are in the same position in the width direction of the crank pulley 2 when the belt mounting jig 6 is installed on the outer circumference of the crank pulley 2. This makes it possible to further suppress misalignment of the belt mounting jig 6 in the width direction of the crank pulley 2 when installing the belt mounting jig 6 on the outer circumference of the crank pulley 2.

[0056] Furthermore, if the sum of central angles A and B becomes smaller, the inclination angle β (see Figure 10(B)) in the width direction of the crank pulley 2 relative to the circumferential direction of the crank pulley 2 increases in the portion of the V-ribbed belt 4 from the radially inward position of the belt retaining portion 62 up to the pulley pressing portion 61 and hooked onto the belt holding portion 64. When the inclination angle β increases, a sharp bend occurs in the width direction of the crank pulley 2 in the portion of the V-ribbed belt 4 from the radially inward position of the belt retaining portion 62 up to the pulley pressing portion 61 and hooked onto the belt holding portion 64, and the side of the V-ribbed belt 4 that has been sharply bent will bend and deform significantly radially outward. Therefore, by increasing the central angle B, the sum of central angles A and B can also be increased. Thus, within the range that satisfies the above-mentioned ranges of central angles A, B, and C and their respective relationships, it is preferable for central angle B to be as large as possible. This makes it possible to minimize the inclination angle β and suppress deflection in the portion of the V-ribbed belt 4 from the radially inward position of the belt retaining portion 62 to where it rides up onto the pulley pressing portion 61 and is hooked onto the belt holding portion 64.

[0057] (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. This stretches the V-ribbed belt 4, increasing its tension. This tension in the V-ribbed belt 4 acts as a pressing force, pressing the pulley pressing portion 61 of the belt mounting jig 6 against the outer circumference of the crank pulley 2. With the V-ribbed belt 4 pressed against the crank pulley 2 by the belt retaining portion 62, the pulley pressing portion 61 is pressed against the outer circumference of the crank pulley 2 by the V-ribbed belt 4, allowing the V-ribbed belt 4, the belt mounting jig 6, and the crank pulley 2 to rotate more reliably as a single unit.

[0058] Here, if the central angle A is less than 18°, the pressing force of the V-ribbed belt 4 is concentrated on the belt holding part 64. As a result, when the V-ribbed belt 4 moves away from the belt holding part 64 and onto the outer circumference of the crank pulley 2, the V-ribbed belt 4 may not move smoothly onto the outer circumference of the crank pulley 2 and may become misaligned on the outer circumference of the crank pulley 2. In addition, the concentrated pressing force of the V-ribbed belt 4 on the belt holding part 64 may cause the belt mounting jig 6 to deform. Therefore, by setting the central angle A to 18° or more, the pressing force of the V-ribbed belt 4 on the belt mounting jig 6 is distributed, and the pressing force of the V-ribbed belt 4 on the belt holding part 64 is reduced. As a result, the V-ribbed belt 4 moves smoothly away from the belt holding part 64 onto the outer circumference of the crank pulley 2, preventing the V-ribbed belt 4 from shifting on the outer circumference of the crank pulley 2. In addition, the reduction in the pressing force of the V-ribbed belt 4 on the belt holding part 64 prevents deformation of the belt mounting jig 6.

[0059] If the central angle of the pulley pressing portion 61 is less than 18°, the pressing force on the crank pulley 2 by the pulley pressing portion 61, which is under tension from the V-ribbed belt 4, will be concentrated, increasing the load on the crank pulley 2 and potentially causing the crank pulley 2 to break. Therefore, by setting the central angle of the pulley pressing portion 61 to 18° or more, the load on the crank pulley 2 can be reduced.

[0060] Furthermore, as shown in Figures 12 and 13, if the crank pulley 2 is continuously rotated in the rotational direction X, 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 increases. In this case as well, if the central angle A is 18° or greater, the pressing force of the V-ribbed belt 4 on the belt mounting jig 6 is distributed, and the pressing force of the V-ribbed belt 4 on the belt holding part 64 is reduced, so that the V-ribbed belt 4 can move more smoothly from the belt holding part 64 onto the outer circumference of the crank pulley 2. As a result, rib displacement of the V-ribbed belt 4 on the outer circumference of the crank pulley 2 can be prevented.

[0061] (Procedure (d)) Furthermore, as shown in Figures 14 and 15, if the crank pulley 2 is continued to rotate in the rotational direction X, the pressing action of the pulley pressing portion 61 against the outer circumference of the crank pulley 2 due to the tension of the V-ribbed belt 4 disappears, and the belt mounting jig 6 can be detached from the crank pulley 2. If the crank pulley 2 is rotated further in the rotational direction X, the relationship in which the belt retaining portion 62 presses the V-ribbed belt 4 against the outer circumference of the crank pulley 2 is also released, and the belt mounting jig 6 is ejected from the crank pulley 2 while hanging from the V-ribbed belt 4. The belt mounting jig 6 can be retrieved at this time.

[0062] The belt attached by the belt attachment jig of the present invention may be a belt other than a V-ribbed belt, such as a flat belt.

[0063] Furthermore, in the belt mounting jig of the present invention, if the pulley pressing portion is connected to the connecting portion via a plurality of folds, the belt retaining portion may be connected to the connecting portion without passing through folds.

[0064] Furthermore, in the belt mounting jig of the present invention, the portion of the connecting portion that connects the pulley pressing portion and the belt retaining portion, including the portion in the circumferential direction of the first pulley from the position connected to the pulley pressing portion to the position connected to the belt retaining portion, does not have to be formed in an arc shape centered on the rotation center of the first pulley when the belt mounting jig is installed on the outer circumference of the first pulley. In this case, the connecting portion does not have to be arc-shaped. Note that the portion of the connecting portion that connects the pulley pressing portion and the belt retaining portion, including the portion in the circumferential direction of the first pulley from the position connected to the pulley pressing portion to the position connected to the belt retaining portion, corresponds in the above embodiment to the portion of the connecting portion 65 between the first contact portion 651 and the belt holding portion 64.

[0065] (Second Embodiment) Next, the belt mounting jig 206 according to the second embodiment will be described with reference to Figures 16 to 19. Components common to the belt mounting jig 6 of the first embodiment are denoted by the same reference numerals and their descriptions are omitted; the focus will be on the differences.

[0066] The belt mounting jig 206 according to the second embodiment includes, similar to the first embodiment, 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 that connects these.

[0067] In this second embodiment, the belt mounting jig 206 has a first connecting portion 2614 that connects the connecting portion 65 and the pulley pressing portion 61, which differs from the first embodiment in that there is no fold in the connection between the connecting portion 65 and the pulley pressing portion 61. Furthermore, the belt mounting jig 206 of the second embodiment has no folds from the connecting portion 65 to the pulley pressing portion 61 and is formed flat to follow the outer circumference of the crank pulley 2. In other words, the first connecting portion 2614 in the second embodiment is not formed in such a way as the first connecting portion 614 in the first embodiment, where it is connected to the connecting portion 65 via a fold 611 bent radially inward from the connecting portion 65 to the crank pulley 2, and connected to the pulley pressing portion 61 via a fold 612 bent radially outward from the pulley pressing portion 61 to the crank pulley 2. Furthermore, the belt mounting jig 206 in the second embodiment is configured as a flat portion that continuously connects the connecting portion 65, the first connecting portion 2614, and the pulley pressing portion 61, and is formed in a continuous planar shape without folds or steps caused by folds between the connecting portion 65 and the first connecting portion 2614, and between the pulley pressing portion 61 and the first connecting portion 2614. In the present invention, the first connecting portion refers to the portion that connects the connecting portion 65 and the pulley pressing portion 61, and includes both cases: one in which it is interposed between the connecting portion 65 and the pulley pressing portion 61 and has a certain area, as in the first connecting portion 614 of the first embodiment, and another in which it is configured as a linear portion that extends along the boundary between the connecting portion 65 and the pulley pressing portion 61, as in the first connecting portion 2614 of the second embodiment.

[0068] Furthermore, in the belt mounting jig 206, the first connecting portion 2614 is connected to the connecting portion 65 and the pulley pressing portion 61 without a fold, and there are no folds from the connecting portion 65 to the pulley pressing portion 61, and it is formed flat along the outer circumference of the first pulley. As a result, as shown in Figure 18, the relationship between the distance D from the rotation center DC of the crank pulley 2 to the radially inner surface of the belt pressing portion 62 that contacts the V-ribbed belt 4 and the distance E from the rotation center DC of the crank pulley 2 to the radially outer surface of the pulley pressing portion 61 that contacts the V-ribbed belt 4 is not particularly limited. For example, in the belt mounting jig 206, distance D may be greater than distance E, distance D may be less than distance E, or distance D and distance E may be the same.

[0069] Furthermore, as shown in Figure 17, the belt mounting jig 206, similar to the first embodiment, has a fold 621 (corresponding to the third fold) bent radially inward from the connecting portion 65, and a fold 622 (corresponding to the fourth fold) bent radially outward from the belt retaining portion 62 to the crank pulley 2, and is equipped with a second connecting portion 624 that connects the connecting portion 65 and the belt retaining portion 62.

[0070] As described above, in the second embodiment, the belt mounting jig 206 is formed such that the first connecting portion 2614 does not have a fold when connecting to the connecting portion 65 and the pulley pressing portion 61. Furthermore, the belt mounting jig 206 has no folds from the connecting portion 65 to the pulley pressing portion 61 and is formed flat along the outer circumference of the first pulley. Therefore, when the V-ribbed belt 4 is placed diagonally over the pulley pressing portion 61, the pressing force acting from the V-ribbed belt 4 to the belt mounting jig 206 is easily distributed across the connecting portion 65, the first connecting portion 2614, and the pulley pressing portion 61. As a result, compared to the configuration in the first embodiment, where the first connecting portion 614 is connected to the connecting portion 65 and the pulley pressing portion 61 via folds 611 and 612, and a step is formed between the connecting portion 65 and the pulley pressing portion 61 by these folds 611 and 612, the local concentration of stress acting from the V-ribbed belt 4 to the belt mounting jig 206 is suppressed, and the increase in local stress occurring in the V-ribbed belt 4 and the belt mounting jig 206, as well as the resulting rattle due to the tilting of the belt mounting jig 206, can be suppressed. Furthermore, since the second connecting portion 624 has a fold 621 bent radially inward from the connecting portion 65 to the crank pulley 2, and a fold 622 bent radially outward from the belt retaining portion 62 to the crank pulley 2, the belt retaining portion 62 can press the V-ribbed belt 4 from the upper side of the V-ribbed belt 4 so that it follows the outer circumference of the crank pulley 2 without lifting up from the crank pulley 2, thereby suppressing the occurrence of so-called rib misalignment, where the V-ribbed belt 4 shifts away from the crank pulley 2, when the V-ribbed belt 4 is attached to the crank pulley 2. This reduces the load on the V-ribbed belt 4 and the belt mounting jig 206, stabilizes the positioning of the V-ribbed belt 4, and improves the workability when attaching the V-ribbed belt 4 to the crank pulley 2. [Examples]

[0071] 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.

[0072] [Belt mounting jig] In the examples and comparative examples, the central angle (center angle A) from the boundary between the pulley pressing portion and the belt insertion hole to the belt holding portion, the central angle (center angle B) of the belt insertion hole, the central angle (center angle C) of the belt retaining portion, and the presence or absence of folds (first fold, second fold) in the first connecting portion connecting the connecting portion and the pulley pressing portion, and the presence or absence of folds (third fold, fourth fold) in the second connecting portion connecting the connecting portion and the belt retaining portion were changed as shown in Tables 1 to 5. All other configurations were common, and the following conditions were also common.

[0073] 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.

[0074] [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.

[0075] [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.

[0076] [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.

[0077] (Judgment criteria) A rating: Belt installation is possible, and the installation 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.

[0078] [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 acceptance of the belts in actual use for this application, i.e., the absence of damage due to deflection, a rating of "a" was given as a pass.

[0079] (Judgment criteria) A rating: If the belt is undamaged. C rating: If the belt is damaged.

[0080] [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.

[0081] (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.

[0082] [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.

[0083] (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).

[0084] [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.

[0085] [Verification Results and Discussion] The verification results are shown in Tables 1-5.

[0086] <Table 1: Examples of changes in the presence or absence of folds at the first and second connection points> [Table 1]

[0087] (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).

[0088] <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]

[0089] (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).

[0090] (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).

[0091] (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.

[0092] (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.

[0093] <Table 3: Example of changing the central angle A based on Example 1> [Table 3]

[0094] (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.

[0095] <Table 4: Example of changing the central angle C based on Example 1> [Table 4]

[0096] (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 A 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.

[0097] <Table 5: An example of changing central angles A and C based on Example 5> [Table 5]

[0098] (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.

[0099] <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.

[0100] (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.

[0101] (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 Example 2 shown in Figure 20(A), as shown in Figure 20(B), the pressure exerted by the V-ribbed belt 4 on the belt mounting jig 6 in the set state is locally concentrated near the area between the pulley pressing portion 61 and the first connection portion 614. On the other hand, in the configuration of the belt mounting jig 206 of Example 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 evenly distributed across the pulley pressing portion 61 and the first connection portion 2614. Furthermore, the maximum Mises stress applied to the overlapping portion of the V-ribbed belt 4 was 200 MPa in Example 2, while it was significantly smaller at 8 MPa in Example 1. In other words, compared to the belt mounting jig 6 of Embodiment 2, which has a fold in the first connection part, the belt mounting jig 206 of Embodiment 1, which has a flat configuration without a fold in the first connection part, is presumed to have a smaller load on the belt mounting jig 206 because the stress pressed by the V-ribbed belt 4 is distributed over the entire area where the V-ribbed belt 4 rides onto the belt mounting jig 206 when it is set up.

[0102] (Effects obtained) Based on the above verification results, if we define central angle A as the central angle from the boundary between the pulley pressing portion and the belt insertion hole to the belt holding portion, central angle B as the central angle of the belt insertion hole, and central angle C as the central angle of the belt retaining portion, then a belt mounting jig in which central angle B is 18° or more and the sum of central angles A, B, and C is 90° or less can be said to be a configuration that allows for easy belt mounting while preventing damage to the belt during belt mounting to the pulley. Furthermore, when central angle A is 18° or greater, when central angle C is 12° or greater, and when the sum of central angles A, B, and C is 75° or less, this configuration is particularly well-balanced in terms of ease of installation, load on the belt, load on the belt mounting jig, and rib slippage. Moreover, when the first connection part has a flat configuration without folds (first fold, second fold), and the second connection part has folds (third fold, fourth fold), this configuration is also particularly preferable in terms of ease of installation, load on the belt, load on the belt mounting jig, and rib slippage. [Explanation of symbols]

[0103] 2. Crank pulley (first pulley) 3 Alternator pulley 4 V-ribbed belt 6. Belt mounting jig 61 Pulley pressing section 614, 2614 First connection section 62 Belt retaining part 621 Fold (3rd fold) 622 Fold (4th fold) 624 Second connection section 63 Belt insertion holes 64 Belt holding part 65 Connecting part

Claims

1. A set of a first pulley and a belt mounting jig used to wrap a belt, which is wrapped around at least one pulley, around a first pulley different from the at least one pulley, The first pulley and, The belt mounting jig is provided, The aforementioned belt mounting jig is A pulley pressing portion is positioned on the outer circumference of the first pulley, and a portion of the belt is placed diagonally with respect to the circumferential direction of the first pulley, and is pressed against the outer circumference of the first pulley by the tension of the belt, A belt retaining portion is positioned on the outer circumference of the first pulley and presses the portion of the belt that runs along the outer circumference of the first pulley against the outer circumference of the first pulley, A belt insertion hole is provided on the outer circumference of the first pulley, between the pulley pressing portion and the belt retaining portion, through which the belt is inserted, The first pulley is positioned in the circumferential direction of the first pulley, at a position further from the belt retaining portion than the boundary between the pulley pressing portion and the belt insertion hole, and includes a belt holding portion that hooks onto and holds the portion of the belt that is off the outer circumference of the first pulley, With the belt mounting jig installed on the outer circumference of the first pulley, The central angle A is defined as the central angle from the boundary between the pulley pressing portion and the belt insertion hole to the belt holding portion, with respect to the rotation center of the first pulley. Let the central angle B be the central angle of the belt insertion hole with respect to the rotation center of the first pulley. When the central angle of the belt retaining portion of the first pulley, centered on the rotation center, is defined as the central angle C, A set of a first pulley and 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 central angles A, B, and C is 90° or less.

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

3. A connecting portion is positioned off the outer circumference of the first pulley and connects the pulley pressing portion and the belt holding portion, A first connecting portion that connects the aforementioned connecting portion and the aforementioned pulley pressing portion, It includes a second connecting portion that connects the aforementioned connecting portion and the aforementioned belt retaining portion, The first connecting portion, in its connection with the connecting portion and the pulley pressing portion, is flat along the outer circumference of the first pulley without any folds, from the connecting portion to the pulley pressing portion. The set of a first pulley and a belt mounting jig according to claim 1 or 2, characterized in that the second connecting portion has a third fold bent radially inward from the connecting portion toward the first pulley, and a fourth fold bent radially outward from the belt retaining portion toward the first pulley.

4. A belt mounting method comprising wrapping a belt, which is wrapped around at least one pulley, around a first pulley different from the at least one pulley, A pulley pressing portion is positioned on the outer circumference of the first pulley, and a portion of the belt is placed diagonally with respect to the circumferential direction of the first pulley, and is pressed against the outer circumference of the first pulley by the tension of the belt, A belt retaining portion is positioned on the outer circumference of the first pulley and presses the portion of the belt that runs along the outer circumference of the first pulley against the outer circumference of the first pulley, A belt insertion hole is provided on the outer circumference of the first pulley, between the pulley pressing portion and the belt retaining portion, through which the belt is inserted, A belt mounting jig is used, which includes a belt holding portion positioned in the circumferential direction of the first pulley, at a position further from the belt holding portion than the boundary between the pulley pressing portion and the belt insertion hole, and which hooks and holds the portion of the belt that is off the outer circumference of the first pulley, The steps include installing the belt mounting jig on the outer circumference of the first pulley, The steps include aligning a portion of the belt along the outer circumference of the first pulley, The process of inserting the belt into the belt insertion hole while pressing the belt against the outer circumference of the first pulley with the belt retaining portion, The process involves moving the belt that has passed through the belt insertion hole onto the pulley pressing portion and hooking it onto the belt holding portion, The process includes the step of rotating the first pulley to move the belt held in the belt holding portion to the outer circumference of the first pulley, thereby wrapping the belt around the first pulley. With the belt mounting jig installed on the outer circumference of the first pulley, The central angle A is defined as the central angle from the boundary between the pulley pressing portion and the belt insertion hole to the belt holding portion, with respect to the rotation center of the first pulley. Let the central angle of the belt insertion hole centered on the rotation center of the first pulley be the central angle B. When the central angle of the belt retaining portion with respect to the rotation center of the first pulley is defined as the central angle C, A belt mounting method 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 central angles A, B, and C is 90° or less.

5. The belt mounting method according to claim 4, characterized in that the sum of the central angle A, the central angle B, and the central angle C is 75° or less.

6. The aforementioned belt mounting jig is A connecting portion is positioned off the outer circumference of the first pulley and connects the pulley pressing portion and the belt holding portion, A first connecting portion that connects the aforementioned connecting portion and the aforementioned pulley pressing portion, A second connecting portion that connects the aforementioned connecting portion and the belt retaining portion, Equipped with, The first connecting portion is flat along the outer circumference of the first pulley, without any folds in the connection between the connecting portion and the pulley pressing portion, and without any folds from the connecting portion to the pulley pressing portion. The belt mounting method according to claim 4 or 5, characterized in that the second connecting portion has a third fold bent radially inward from the connecting portion toward the first pulley, and a fourth fold bent radially outward from the belt retaining portion toward the first pulley.

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