Alternator

Abstract

To provide an alternator that suppresses generation of frictional heat while preventing a pulley from falling from a rotating shaft.SOLUTION: An alternator includes: a body part; a rotating shaft rotatably provided in the body part; a pulley fixed to the rotating shaft; a belt wound around the pulley and cooperating with a crank shaft of an engine; and a falling prevention member fixed to the body part and preventing the pulley from falling from the rotating shaft. The falling prevention member faces the rotating shaft and the pulley while separating from the rotating shaft and the pulley in an axial direction of the rotating shaft. A width in the axial direction of the belt is narrower than that in the axial direction of the pulley. A distance between the falling prevention member and the belt in the axial direction is equal to or longer than the width in the axial direction of the pulley. A distance between the falling prevention member and the rotating shaft in the axial direction is shorter than the width in the axial direction of the pulley.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an alternator. [Background technology]

[0002] A pulley around which a belt is wound and a disengagement prevention member that prevents the pulley from disengaging from the rotating shaft are fixed to the rotating shaft of the alternator in Patent Document 1. The disengagement prevention member is fixed to the tip side of the rotating shaft from the pulley. For example, if the fixing member that fixed the pulley to the rotating shaft comes off, the pulley will rotate freely relative to the rotating shaft due to the power from the belt. In this state, the pulley comes into contact with the disengagement prevention member, thereby preventing the pulley from disengaging from the rotating shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 158870 Summary of the Invention [Problem to be solved by the invention]

[0004] When the idling pulley comes into contact with the anti-disengagement member in this manner, frictional heat may be generated between the pulley and the anti-disengagement member.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an alternator that prevents the pulley from falling off the rotating shaft while suppressing the generation of frictional heat. [Means for solving the problem]

[0006] The above object can be achieved by an alternator comprising: a main body, a rotating shaft rotatably mounted on the main body, a pulley fixed to the rotating shaft, a belt wound around the pulley and linked to a crankshaft of an engine, and a fall-off prevention member fixed to the main body for preventing the pulley from falling off from the rotating shaft, wherein the fall-off prevention member faces the rotating shaft and is spaced apart from the rotating shaft and pulley in the axial direction of the rotating shaft, the width of the belt in the axial direction being narrower than the width of the pulley in the axial direction, the distance between the fall-off prevention member and the belt in the axial direction being equal to or greater than the width of the pulley in the axial direction, and the distance between the fall-off prevention member and the rotating shaft in the axial direction being shorter than the width of the pulley in the axial direction.

[0007] The axial distance between the anti-slip member and the rotating shaft may be shorter than the axial distance between the anti-slip member and the pulley, and the axial distance between the anti-slip member and the rotating shaft may be greater than or equal to the width of the belt in the axial direction.

[0008] The axial distance between the anti-slip member and the rotating shaft is longer than the axial distance between the anti-slip member and the pulley, and the axial distance between the anti-slip member and the pulley may be greater than or equal to the width of the belt in the axial direction.

[0009] The axial distance between the anti-slip member and the rotating shaft may be the same as the axial distance between the anti-slip member and the pulley, and the axial distance between the anti-slip member and each of the rotating shaft and the pulley may be greater than or equal to the width of the belt in the axial direction.

[0010] The anti-disengagement member may be fixed to the main body in a cantilevered state. Effect of the Invention

[0011] It is possible to provide an alternator in which the pulley is prevented from falling off the rotating shaft while suppressing the generation of frictional heat. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of an alternator. [Diagram 2] FIG. 2 is an enlarged view of the pulley and its surroundings. [Diagram 3] FIG. 3A is a diagram showing a state in which the pulley has moved toward the opposing wall and the belt has fallen off the pulley, and FIG. 3B is a diagram showing a case in which the pulley has come into contact with the opposing wall. [Figure 4] FIG. 4 is a diagram showing a state in which the belt has fallen off the pulley toward the opposing wall portion. [Diagram 5] FIG. 5A is an enlarged view of the periphery of a pulley in a first modified example, and FIG. 5B is an enlarged view of the periphery of a pulley in a second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] FIG. 1 is a schematic diagram of an alternator 10. The alternator 10 is a generator that generates electricity using the power of an engine 100. The alternator 10 includes a main body 10a, a rotating shaft 12, a pulley 14, a belt 16, and a drop-off prevention member 20. The rotating shaft 12 is rotatably provided on the main body 10a. The pulley 14 is fixed to the tip of the rotating shaft 12. The engine 100 includes a main body 110a, a crankshaft 112, and a pulley 114. The crankshaft 112 is rotatably provided on the main body 110a. The pulley 114 is fixed to the tip of the crankshaft 112. The belt 16 is wound around the pulley 14 and the pulley 114. As a result, the rotation of the crankshaft 112 is transmitted to the rotating shaft 12 via the belt 16. When the rotating shaft 12 rotates, electric power is generated in the main body 10a.

[0014] The fall-prevention member 20 is fixed in a cantilevered state to the main body 10a. The fall-prevention member 20 is a plate member bent into an L-shape. The fall-prevention member 20 is made of, for example, metal. The fall-prevention member 20 includes a fixed wall portion 21 and an opposing wall portion 22. The fixed wall portion 21 is fixed to the side surface of the main body 10a by a bolt or the like. The opposing wall portion 22 is bent at a substantially right angle from the fixed wall portion 21. The tip of the opposing wall portion 22 is not fixed to any member.

[0015] Fig. 2 is an enlarged view of the pulley 14 and its surroundings. The pulley 14 has a through hole 14a through which the rotating shaft 12 passes. A groove 14b for holding the belt 16 is formed on the outer circumferential surface of the pulley 14. Fig. 2 shows the pulley 14 fixed at a desired position relative to the rotating shaft 12. In the example of Fig. 2, the tip of the rotating shaft 12 protrudes toward the opposing wall portion 22 beyond the pulley 14. The opposing wall portion 22 faces the rotating shaft 12 and pulley 14, separated from them in the axial direction D.

[0016] A width A of the belt 16 in the axial direction D is narrower than a width B of the pulley 14 in the axial direction D. A distance C1 in the axial direction D between the opposing wall portion 22 and the rotating shaft 12 is shorter than a distance C2 in the axial direction D between the opposing wall portion 22 and the pulley 14. The distance C2 is shorter than a distance C3 in the axial direction D between the opposing wall portion 22 and the belt 16. In this embodiment, the following first to third conditions are satisfied. The first condition is that the distance C3 is equal to or greater than the width B. The second condition is that the distance C1 is shorter than the width B. The third condition is that the distance C1 is equal to or greater than the width A.

[0017] When the member that fixed the pulley 14 to the rotating shaft 12 comes off, the pulley 14 becomes able to move in the axial direction D. For example, it is considered that the pulley 14 moves toward the opposing wall portion 22. In this case, due to the first condition, the pulley 14 is allowed to move toward the opposing wall portion 22 so that the belt 16 falls off the pulley 14 without being hindered by the opposing wall portion 22. FIG. 3A is a diagram showing a state in which the pulley 14 moves toward the opposing wall portion 22 and the belt 16 falls off the pulley 14. As the belt 16 falls off the pulley 14, the power is not transmitted from the engine 100 to the rotating shaft 12 and the pulley 14. Therefore, the rotating shaft 12 and the pulley 14 rotate by inertia and then stop.

[0018] The second condition prevents the pulley 14 from coming off the rotating shaft 12 due to the pulley 14 coming into contact with the opposing wall portion 22. Fig. 3B is a diagram showing a case where the pulley 14 comes into contact with the opposing wall portion 22. Here, as described above, the power of the engine 100 is not transmitted to the alternator 10. Therefore, even if the pulley 14 comes into contact with the opposing wall portion 22, the pulley 14 does not rotate, and the generation of frictional heat between the pulley 14 and the opposing wall portion 22 is suppressed.

[0019] It is also assumed that the belt 16 falls off from the pulley 14 fixed to the rotating shaft 12 toward the opposing wall 22 due to a decrease in tension of the belt 16, etc. In this case, due to the third condition, the belt 16 is able to fall off from the rotating shaft 12 and the pulley 14 without being hindered by the opposing wall 22. FIG. 4 is a diagram showing a state in which the belt 16 has fallen off from the pulley 14 toward the opposing wall 22. This prevents the belt 16 from coming into contact with the opposing wall 22, and suppresses the generation of frictional heat between the belt 16 and the opposing wall 22.

[0020] In addition, the fall-prevention member 20 is fixed to the main body 10a. For example, as compared with a case in which the fall-prevention member is fixed to the rotating shaft 12, the resistance to the rotation of the rotating shaft 12 is reduced. This prevents a decrease in the power generation efficiency of the alternator 10. Furthermore, the fall-prevention member 20 is fixed to the main body 10a in a cantilevered state. This allows the fall-prevention member 20 to be easily attached to the alternator 10 even if the space for attaching the fall-prevention member 20 to the alternator 10 is narrow.

[0021] [Variations] Next, a number of modified examples will be described. The same components as those in the above embodiment are denoted by the same reference numerals, and the description will be omitted. FIG. 5A is an enlarged view of the pulley 14 and its surroundings in the first modified example. FIG. 5A shows the pulley 14 fixed at a desired position relative to the rotating shaft 12. In the example of FIG. 5A, the pulley 14 is fixed to the rotating shaft 12 at a position protruding toward the opposing wall portion 22 side from the tip of the rotating shaft 12. Therefore, in the first modified example, unlike the above embodiment, the distance C1 is longer than the distance C2. The first and second conditions in this case are the same in the first modified example and the above embodiment. The third condition is that the distance C2 is equal to or greater than the width A, unlike the above embodiment. This avoids contact between the belt 16 and the opposing wall portion 22, and suppresses the generation of frictional heat between the belt 16 and the opposing wall portion 22.

[0022] FIG. 5B is an enlarged view of the pulley 14 and its surroundings in the second modified example. FIG. 5B shows the pulley 14 fixed at a desired position relative to the rotating shaft 12a. In the example of FIG. 5B, the pulley 14 is fixed to the rotating shaft 12a so that the surface of the pulley 14 on the opposing wall portion 22 side coincides with the tip of the rotating shaft 12a. Therefore, in the second modified example, the distance C1 is the same as the distance C2. The first and second conditions in this case are the same in the second modified example and the above-mentioned embodiment. The third condition is that the distances C1 and C2 are each equal to or greater than the width A. In this case as well, the generation of frictional heat described above is suppressed.

[0023] The size of the opposing wall 22 in a plane perpendicular to the axial direction D does not necessarily have to be larger than the diameter of the pulley 14. For example, a part of the opposing wall 22 may be included in the area obtained by projecting the pulley 14 onto the opposing wall 22 side in the axial direction D. In this case as well, the pulley 14 comes into contact with the opposing wall 22, and the pulley 14 can be prevented from falling off the rotating shaft 12.

[0024] Although a preferred embodiment of the present invention has been described in detail above, the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0025] 10. Alternator 10a Main body 12 Rotation axis 14 Pulley 16 Belt 20 Anti-falling parts 21 Fixed wall section 22 Opposing wall 100 Engine A, B width C1, C2, C3 distance

Claims

1. A main body portion, A rotation shaft rotatably provided on the main body portion; A pulley fixed to the rotating shaft; A belt wound around the pulley and linked to the crankshaft of the engine; a fall-prevention member fixed to the main body portion and configured to prevent the pulley from falling off the rotating shaft, the fall-off prevention member faces the rotating shaft and the pulley and is spaced from the rotating shaft and the pulley in the axial direction of the rotating shaft, The width of the belt in the axial direction is narrower than the width of the pulley in the axial direction, a distance between the fall-off prevention member and the belt in the axial direction is equal to or greater than a width of the pulley in the axial direction, an axial distance between the anti-disengagement member and the rotating shaft being shorter than an axial width of the pulley;

2. a distance in the axial direction between the fall-off prevention member and the rotating shaft is shorter than a distance in the axial direction between the fall-off prevention member and the pulley, 2. The alternator according to claim 1, wherein a distance between said anti-disengagement member and said rotating shaft in said axial direction is equal to or greater than a width of said belt in said axial direction.

3. a distance in the axial direction between the fall-off prevention member and the rotating shaft is longer than a distance in the axial direction between the fall-off prevention member and the pulley, 2. The alternator according to claim 1, wherein a distance between said anti-disengagement member and said pulley in said axial direction is equal to or greater than a width of said belt in said axial direction.

4. a distance in the axial direction between the fall-off prevention member and the rotating shaft is the same as a distance in the axial direction between the fall-off prevention member and the pulley, 2. The alternator according to claim 1, wherein a distance between said anti-disengagement member and each of said rotating shaft and pulley in said axial direction is equal to or greater than a width of said belt in said axial direction.

5. 5. The alternator according to claim 1, wherein the stopper member is fixed to the main body in a cantilevered state.

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