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 Art

[0002] A pulley around which a belt is wound and a dropout prevention member for preventing the pulley from dropping off the rotating shaft are fixed to the rotating shaft of the alternator of Patent Document 1. The dropout prevention member is fixed to the tip side of the rotating shaft rather than the pulley. For example, if a fixing member that fixes the pulley to the rotating shaft comes off, the pulley idles with respect to the rotating shaft by the power from the belt. When the pulley comes into contact with the dropout prevention member in such a state, the dropout of the pulley from the rotating shaft is prevented.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the pulley that has idled in this way comes into contact with the dropout prevention member, there is a risk of generating frictional heat between the pulley and the dropout prevention member.

[0005] Therefore, an object of the present invention is to provide an alternator that suppresses the generation of frictional heat while preventing the pulley from dropping off the rotating shaft.

Means for Solving the Problems

[0006] The above objective 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 the crankshaft of an engine, and a fall prevention member fixed to the main body to prevent the pulley from falling off the rotating shaft, wherein the fall prevention member is positioned away from the rotating shaft and pulley in the axial direction of the rotating shaft and faces the rotating shaft and the rotating shaft, the width of the belt in the axial direction is narrower than the width of the pulley in the axial direction, the distance between the fall prevention member and the belt in the axial direction is greater than or equal to the width of the pulley in the axial direction, and the distance between the fall prevention member and the rotating shaft in the axial direction is shorter than the width of the pulley in the axial direction.

[0007] The axial distance between the fall prevention member and the rotating shaft may be shorter than the axial distance between the fall prevention member and the pulley, and the axial distance between the fall prevention member and the rotating shaft may be greater than or equal to the axial width of the belt.

[0008] The axial distance between the fall prevention member and the rotating shaft may be longer than the axial distance between the fall prevention member and the pulley, and the axial distance between the fall prevention 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 fall prevention member and the rotating shaft is the same as the axial distance between the fall prevention member and the pulley, and the axial distance between the fall prevention member and the rotating shaft and the pulley, respectively, may be greater than or equal to the axial width of the belt.

[0010] The anti-detachment member may be fixed to the main body in a cantilevered manner. [Effects of the Invention]

[0011] This provides an alternator that prevents the pulley from falling off the rotating shaft while suppressing the generation of frictional heat. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram of the alternator configuration. [Figure 2] Figure 2 is a magnified view of the area around the pulley. [Figure 3] Figure 3A shows the state where the pulley has moved toward the opposing wall and the belt has fallen off the pulley, while Figure 3B shows the state where the pulley is in contact with the opposing wall. [Figure 4] Figure 4 shows the state in which the belt has fallen off the pulley towards the opposing wall. [Figure 5] Figure 5A is a magnified view of the area around the pulley in the first modified example, and Figure 5B is a magnified view of the area around the pulley in the second modified example. [Modes for carrying out the invention]

[0013] Figure 1 is a schematic diagram of the alternator 10. The alternator 10 is a generator that generates electricity using the power of the engine 100. The alternator 10 includes a main body 10a, a rotating shaft 12, a pulley 14, a belt 16, and a fall prevention member 20. The rotating shaft 12 is rotatably mounted 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 mounted 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. As a result, the rotation of the crankshaft 112 is transmitted to the rotating shaft 12 via the belt 16. Electricity is generated in the main body 10a as the rotating shaft 12 rotates.

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

[0015] Figure 2 is an enlarged view of the area around the pulley 14. 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. Figure 2 shows the pulley 14 fixed in a desired position relative to the rotating shaft 12. In the example in Figure 2, the tip of the rotating shaft 12 protrudes further toward the opposing wall portion 22 than the pulley 14. The opposing wall portion 22 is located away from the rotating shaft 12 and the pulley 14 in the axial direction D and faces the rotating shaft 12 and the pulley 14.

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

[0017] When the member that fixed the pulley 14 to the rotating shaft 12 comes off, the pulley 14 can move in the axial direction D. For example, it is conceivable that the pulley 14 moves toward the opposing wall portion 22. In this case, according to the first condition, the movement of the pulley 14 toward the opposing wall portion 22 that allows the belt 16 to fall off the pulley 14 is permitted without being obstructed by the opposing wall portion 22. FIG. 3A is a diagram showing a state where the pulley 14 has moved toward the opposing wall portion 22 and the belt 16 has fallen off the pulley 14. When the belt 16 falls off the pulley 14, power from the engine 100 is not transmitted to the rotating shaft 12 and the pulley 14. Therefore, the rotating shaft 12 and the pulley 14 rotate inertially and then stop.

[0018] According to the second condition, when the pulley 14 contacts the opposing wall portion 22, the pulley 14 is prevented from falling off the rotating shaft 12. FIG. 3B is a diagram showing the case when the pulley 14 contacts the opposing wall portion 22. Here, as described above, the power of the engine 100 is not transmitted to the alternator 10. Therefore, even when the pulley 14 contacts 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] Also, assume that the belt 16 falls off the pulley 14 fixed to the rotating shaft 12 toward the opposing wall portion 22 due to a decrease in the tension of the belt 16 or the like. In this case, according to the third condition, the belt 16 can fall off the rotating shaft 12 and the pulley 14 without being obstructed by the opposing wall portion 22. FIG. 4 is a diagram showing a state where the belt 16 has fallen off the pulley 14 toward the opposing wall portion 22. Thereby, contact between the belt 16 and the opposing wall portion 22 is avoided, and the generation of frictional heat between the belt 16 and the opposing wall portion 22 is suppressed.

[0020] Further, the anti-drop member 20 is fixed to the main body portion 10a. For example, compared with the case where the anti-drop member is fixed to the rotating shaft 12, the resistance to the rotation of the rotating shaft 12 is reduced. Therefore, the decrease in the power generation efficiency of the alternator 10 is suppressed. Further, the anti-drop member 20 is fixed to the main body portion 10a in a cantilever state. Therefore, even when the space for attaching the anti-drop member 20 to the alternator 10 is narrow, the anti-drop member 20 can be easily attached to the alternator 10.

[0021] [Modification Example] Next, a plurality of modification examples will be described. For the configurations of the modification examples that are the same as those of the above-described embodiment, the same reference numerals are given and the overlapping descriptions are omitted. FIG. 5A is an enlarged view around the pulley 14 in the first modification example. FIG. 5A shows the pulley 14 fixed at a desired position with respect 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 modification example, unlike the above-described embodiment, the distance C1 is longer than the distance C2. Regarding the first and second conditions in this case, they are the same in the first modification example and the above-described embodiment. The third condition is that, unlike the above-described embodiment, the distance C2 is equal to or greater than the width A. Thereby, contact between the belt 16 and the opposing wall portion 22 is avoided, and generation of frictional heat between the belt 16 and the opposing wall portion 22 is suppressed.

[0022] FIG. 5B is an enlarged view around the pulley 14 in the second modification example. FIG. 5B shows the pulley 14 fixed at a desired position with respect to the rotating shaft 12a. In the example of FIG. 5B, the pulley 14 is fixed to the rotating shaft 12a such 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 modification example, the distance C1 is the same as the distance C2. Regarding the first and second conditions in this case, they are the same in the second modification example and the above-described embodiment. The third condition is that each of the distances C1 and C2 is equal to or greater than the width A. Also in this case, the generation of the above-described frictional heat is suppressed.

[0023] The size of the opposing wall portion 22 in the plane perpendicular to the axial direction D does not necessarily have to be larger than the diameter of the pulley 14. For example, a portion of the opposing wall portion 22 may be included in the region obtained by projecting the pulley 14 toward the opposing wall portion 22 in the axial direction D. In this case as well, the pulley 14 can contact the opposing wall portion 22, preventing it from falling off the rotation shaft 12.

[0024] Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the invention as described in the claims. [Explanation of symbols]

[0025] 10 Alternator 10a Main body 12 Rotation axes 14 Pulley 16 belts 20 Anti-detachment member 21 Fixed wall section 22 Opposing wall section 100 engine A, B width C1, C2, C3 distance

Claims

1. The main body and A rotating shaft is rotatably provided on the main body, A pulley fixed to the aforementioned rotating shaft, A belt wound around the aforementioned pulley and connected to the engine's crankshaft, The system includes a fall prevention member fixed to the main body and preventing the pulley from falling off the rotating shaft, The anti-detachment member is positioned away from the rotating shaft and pulley in the axial direction of the rotating shaft and facing the rotating shaft and pulley, The width of the belt in the axial direction is narrower than the width of the pulley in the axial direction. The distance between the anti-detachment member and the belt in the axial direction is greater than or equal to the width of the pulley in the axial direction. An alternator in which the distance in the axial direction between the anti-detachment member and the rotating shaft is shorter than the width of the pulley in the axial direction.

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

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

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

5. The alternator according to any one of claims 1 to 4, wherein the anti-detachment member is fixed to the main body in a cantilevered manner.

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