JP3771166B2 - Belt transmission and pulley - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a belt transmission device for an automobile engine, and more particularly to a pulley applied to the belt transmission device.
[0002]
[Prior art]
In recent years, automobile transmissions (internal combustion engines) have adopted a belt transmission device that drives a plurality of auxiliary machines with a single endless belt in a multi-axis manner. In particular, V-ribbed belts are widely used as endless belts in order to reduce the space occupied by them. It's being used.
[0003]
In vehicles that do not have an undercover, it is easy to be exposed to water splashes due to the springing up of the tire located at the bottom of the engine during rainy weather, and if the water splashes or gets submerged in the engine room, a stick slip occurs between the belt and pulley. It is known that a minute slip called a phenomenon occurs and a peculiar noise is generated. This abnormal noise is not preferable for the quietness of automobiles in recent years. Conventionally, the belt-to-pulley slip can be achieved by increasing belt tension, aggressively sweeping out water that has penetrated the surface of the belt by protruding microfibers, or increasing the belt ribs to improve grip. However, these measures cannot sufficiently suppress the generation of abnormal noise.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and an object of the present invention is to prevent the generation of abnormal noise even in the case of water injection in a belt transmission device having large rotational fluctuations.
[0005]
[Means for Solving the Problems]
The belt transmission device according to the present invention is characterized by including a V-ribbed belt and a pulley having a coat layer mainly composed of polytetrafluoroethylene formed on a surface around which the V-ribbed belt is wound. Thereby, by generating positive slip between the V-ribbed belt and the pulley and suppressing stick slip, it is possible to prevent the generation of abnormal noise even during water injection.
[0006]
In the belt transmission device described above, the pulley on which the coat layer is formed is preferably a pulley that serves as an abnormal sound source. For example, the pulley having the smallest diameter among the pulleys used in the belt transmission device or the belt transmission device is used. A pulley that receives the largest load among the pulleys is preferable. Generally, it is an alternator pulley that has a relatively small diameter and a large load.
[0007]
The pulley according to the present invention is a pulley provided in a belt transmission device using a V-ribbed belt, wherein a coat layer mainly composed of polytetrafluoroethylene is formed on a surface around which the V-ribbed belt is wound. And
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0009]
FIG. 1 is a layout diagram simply showing a belt transmission apparatus according to an embodiment of the present invention. This belt transmission is provided in an engine room of an automobile (not shown), and is formed by winding an endless V-ribbed belt 10 around a plurality of pulleys 12, 14, 16, 18, and 20. When the crank pulley 12 connected to the crankshaft of the engine, which is a driving source, is rotated, the rotational driving force is transmitted via the V-ribbed belt 10 to an air conditioner pulley 14, a power steering pulley 16, a water pump pulley 18, and Transmission is performed in the order of the alternator pulley 20, and each auxiliary machine is operated. An auto tensioner that elastically presses the V-ribbed belt 10 from the back is disposed between the crank pulley 12 and the water pump pulley 18, and the tensioner pulley 22 of the auto tensioner is located between the solid line position and the broken line position. By swinging at, an appropriate tension is applied to the running V-ribbed belt 10 and vibration of the V-ribbed belt 10 caused by fluctuations in the rotational speed or the like is suppressed.
[0010]
The alternator pulley 20 is the pulley having the smallest diameter in this belt transmission, and is susceptible to fluctuations in the engine speed, that is, fluctuations in the angular velocity of the crank pulley 12. This is because the alternator pulley 20 has a smaller diameter than that of the crank pulley 12, so that the rotational speed thereof is larger than the rotational speed of the crank pulley 12, and the angular speed fluctuation becomes more remarkable. Further, the alternator generates a relatively large load in the belt transmission device for power generation, and the rotation inertia of the alternator pulley 20 itself is large. Therefore, if the speed fluctuation of the V-ribbed belt 10 is large, Minute positional deviations, that is, minute slips are likely to occur.
[0011]
Therefore, a pulley having a large angular velocity fluctuation and a large load such as the alternator pulley 20 is liable to cause stick-slip with the V-ribbed belt 10, and a unique noise is likely to occur. In this embodiment, in order to prevent this stick slip, the alternator pulley 20 is improved as described below.
[0012]
FIG. 2 is a perspective view showing a partially broken alternator pulley 20 together with a part of the V-ribbed belt 10. A plurality of V-shaped protrusions 102 extending in the belt longitudinal direction are formed on the inner peripheral surface of the V-ribbed belt 10, and a V-groove 202 having a dimension and shape corresponding to these V-shaped protrusions 102 is formed on the outer peripheral surface of the alternator pulley 20. The The driving force is transmitted from the V-ribbed belt 10 to the alternator pulley 20 by engaging the V-shaped protrusions 102 and the corresponding V-grooves 202 respectively.
[0013]
The V-ribbed belt 10 includes a belt main body 104 formed of a so-called rubber material and a core cord 106 embedded in the belt main body 104, and the belt surface is covered with a canvas 108 as necessary. The belt body 104 is made of a synthetic rubber excellent in heat resistance and ozone resistance, for example, a compound rubber containing chloroprene rubber or ethylene-propylene-diene terpolymer (EPDM) as a main component, and is necessary for the compound rubber. Depending on the case, short fibers such as cotton and aramid fibers are mixed. The core cord 106 is made of a material such as polyester fiber or aramid fiber having excellent tensile strength.
[0014]
A coat layer 204 mainly composed of polytetrafluoroethylene is formed on the outer peripheral surface of the alternator pulley 20. The coating layer 204 may be provided at least on the outer peripheral surface in contact with the V-ribbed belt 10 as shown in FIG. 2, and the region where the coating layer is provided is not particularly limited to this embodiment.
[0015]
The coat layer 204 is preferably made of a ceramic fluorine paint made by DuPont, which is produced from a blended material containing polytetrafluoroethylene as a main component, and has particularly high hardness, excellent wear resistance and non-adhesiveness. The coating layer 204 is formed by forming the main body 206 of the alternator pulley 20 and then performing a pretreatment for improving the adhesiveness of the ceramic fluorine paint on the outer peripheral surface thereof, and then attaching the ceramic fluorine paint by spraying or the like, Further, the main body 206 applied with the ceramic fluorine paint is baked. Thereby, the coat layer 204 is formed. Note that the above process may be repeated a plurality of times so that the coat layer 204 has a thickness sufficient to withstand abrasion. The main body 206 is preferably formed of a metal material that is easy to mold, has high strength, and can withstand the firing temperature (about 420 ° C.) of the ceramic fluorine paint, such as an iron-based alloy.
[0016]
Conventionally, generally, an alternator pulley has been subjected to a galvanizing treatment or a cationic coating treatment, and a coating layer mainly composed of polytetrafluoroethylene has not been provided. In such a belt transmission using a conventional pulley for an alternator, when water or water containing an electrolyte component (salt content) for preventing freezing enters the engine room, such as when driving in the rain on a car, It is known that a so-called stick-slip phenomenon in which water adheres to cause a microslip and an abnormal noise occurs. This stick-slip phenomenon is caused by fluctuations in engine speed, that is, fluctuations in the angular velocity of the crank pulley 12, and the pulley for the alternator has a smaller diameter than the crank pulley 12 and a relatively large load on the rotating shaft due to the electric load. 20 is likely to occur.
[0017]
Conventionally, by pushing the belt tension toward the alternator pulley side of the V-ribbed belt by increasing the belt tension or setting the height of the V-shaped protrusion of the V-ribbed belt (hereinafter referred to as the rib height) to be larger than the rib height of the conventional belt. Various measures such as reducing pressure by increasing pressure to prevent stick slip, improving the structure or material of the V-ribbed belt, or providing a one-way clutch to prevent excessive stress from acting on the V-ribbed belt. Improvements have been attempted. However, these attempts may not be effective in suppressing the generation of abnormal noise.
[0018]
Therefore, the present applicant provides a coat layer mainly composed of polytetrafluoroethylene having a friction characteristic that a friction coefficient is small and hardly causes stick slip on the outer peripheral surface of the pulley 20 for the alternator, and is used for the V-ribbed belt 10 and the alternator. The pulley 20 is slid positively to some extent. With this configuration, the material of the V-ribbed belt 10 is not changed from the conventional one, and a complicated one-way clutch is not provided, and stick-slip can be prevented even during water injection and the generation of abnormal noise can be reduced. . The belt tension is adjusted to a value that can reliably transmit power from the V-ribbed belt 10 to the alternator pulley 20.
[0019]
When a water injection experiment was performed using the belt transmission device of the present embodiment shown in FIG. 1, it was confirmed that no abnormal noise generation phenomenon was observed. In this water injection test, a ceramic fluorine paint (DuPont) having a heat resistance of 250 ° C. and a Vickers hardness of 77 kgf / mm ² was used as the coat layer of the alternator pulley 20, and the film thickness was about 50 μm. Water injection was performed between the water pump pulley 18 and the alternator pulley 20 (positions indicated by arrows A to E in FIG. 1).
[0020]
In the present embodiment, the coat layer is provided only for the alternator pulley 20, but the coat layer is not particularly limited to the alternator pulley 20, and may be applied to a pulley in which abnormal noise easily occurs in the belt transmission device.
[0021]
【The invention's effect】
As described above, the belt transmission device of the present invention is provided with the coat layer mainly composed of polytetrafluoroethylene on the outer peripheral surface of the pulley for the alternator having a relatively small diameter and a large load, so that the V-ribbed belt 10 and the alternator are provided. Since the slip between the pulleys 20 can be actively slid to prevent stick-slip, there is an advantage that the generation of abnormal noise can be prevented even when water is poured in a belt transmission device with large rotational fluctuation.
[Brief description of the drawings]
FIG. 1 is a layout diagram showing an embodiment of a belt transmission device according to the present invention.
FIG. 2 is a partially cutaway view of the alternator pulley shown in FIG. 1, and is a perspective view showing a part of the V-ribbed belt.
[Explanation of symbols]
10 V-ribbed belt 20 Alternator pulley 204 Coat layer

Claims (2)

A V-ribbed belt is wound around a first pulley and two or more second pulleys, and when the first pulley is rotated, the rotational driving force is transmitted to the two or more second pulleys via the V-ribbed belt. In the belt transmission device transmitted to
Among the second pulleys, only the pulley having the relatively smallest diameter and receiving the largest load has a coat layer mainly composed of polytetrafluoroethylene on the surface on which the V-ribbed belt is wound. A belt transmission device characterized by being formed. A V-ribbed belt is formed by winding a V-ribbed belt around a plurality of pulleys including a crank pulley connected to a crankshaft of an engine and two or more driven pulleys for operating an auxiliary machine. When the crank pulley is rotated, the V-ribbed belt In the multi-shaft auxiliary belt transmission device in which the rotational driving force is transmitted to each driven pulley via
In the driven pulley, only the pulley for the alternator for operating the alternator is provided with a coating layer mainly composed of polytetrafluoroethylene on the surface around which the V-ribbed belt is wound. Machine belt transmission.

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