JP2008095851A - Automobile accessory drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automobile accessory drive device wherein the life of an endless belt can be elongated and the life of the whole device can be elongated while suppressing a change in the pull-in amount of the endless belt of a driving pulley and suppressing a change in the tension of the endless belt even when engine speed varies. <P>SOLUTION: In the automobile accessory drive device 10, the outer peripheral face of the driving pulley 12 mounted at the end of a crank shaft 11a of the engine 11 is formed in an elliptical or polygonal shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an automotive accessory drive device, and more particularly to an automotive accessory that drives an auxiliary machine such as an alternator, a power steering pump, a cooling water circulation pump, an air conditioner compressor, and a cooling fan by an engine of the automobile. The present invention relates to a machine drive device.

  As a conventional automotive accessory drive device, a drive pulley attached to an end of an engine crankshaft, a plurality of accessories provided in the vicinity of the engine, and an end of a rotary shaft of each accessory A driven pulley and an endless belt that is stretched between each driven pulley and the driving pulley, and is provided between the crankshaft and the driving pulley and between the rotating shaft and the driven pulley of at least one auxiliary machine. There is known one provided with a directional clutch (see, for example, Patent Document 1).

  In addition, a driven pulley attached to the rotating shaft of the alternator has a built-in one-way clutch to cancel minute rotation fluctuations associated with engine rotation fluctuations, reduce driving loss by overrunning during deceleration, and endless A clutch pulley unit that reduces belt tension fluctuation and extends belt life is known (see, for example, Patent Document 2).

  Many endless belts are installed on the loose side, and the endless belt is pushed with a constant force using a spring force or hydraulic cylinder to control the tension of the endless belt, improving transmission efficiency and extending the belt life. There is known an auto tensioner for achieving the above (for example, see Patent Document 3).

JP 2002-21953 A JP 2005-106078 A JP 2001-165253 A

  By the way, in general, in an internal combustion engine, even if it is rotated at a constant speed, the crankshaft is rotated using the explosion energy of the air-fuel mixture in each cylinder. In this case, as shown in FIG. 2, four minute rotation fluctuations are generated by two rotations of the crankshaft (phase 720 degrees).

  At this time, in the auxiliary driving apparatus 100 for an automobile shown in FIG. 3, the driving pulley 103 mounted on the crankshaft 102 of the engine 101 has a low rotational speed A and a high rotational speed B. When the endless belt 104 is pulled in, the amount of the endless belt 104 that is pulled in varies, and the alternator 105 and the auto tensioner 106 that are auxiliary machines are slightly increased or decelerated via the endless belt 104.

  Then, since the driving force is transmitted when the speed is increased, the tension of the endless belt 104 between the alternator 105 having a large inertia and the point C of the driving pulley 103 is increased. Conversely, the tension on the end of the endless belt 104 on the auto tensioner 106 side tends to increase. For this reason, tension variation occurs in the endless belt 104, and the life of the endless belt 104 may be reduced. In addition, since load changes occur in each of the auxiliary machines 105 and 106 via the endless belt 104, the life of the entire apparatus may be reduced.

  In addition, since the auxiliary machine driving device and the clutch pulley unit described in Patent Literature 1 and Patent Literature 2 incorporate a one-way clutch in the driving pulley of the crankshaft and the driven pulley of the alternator, the tension setting of the endless belt is reduced. This is effective for extending the life of the belt, improving fuel consumption, preventing belt noise, etc. However, if one-way clutches and decouplers are used frequently in areas where there are many fluctuations in engine rotation, the clutch will be engaged / released. Since it is frequently performed, there is a possibility that mechanical deterioration such as fatigue and wear of the clutch mechanism, early function deterioration, life reduction, etc. may occur in the clutch portion.

  Further, in the auto tensioner described in Patent Document 3, although the tension on the loose side of the endless belt can be made constant, the tension change of the endless belt due to engine rotation fluctuation is caused on the pulling side of the endless belt by an auxiliary machine having a large inertia. It was difficult to absorb completely.

  The present invention has been made in order to eliminate such inconveniences, and the object of the present invention is to suppress fluctuations in the pull-in amount of the endless belt of the drive pulley even if there are fluctuations in the rotation of the engine. It is an object of the present invention to provide an automotive accessory driving device that can suppress fluctuations in tension and extend the life of an endless belt and extend the life of the entire device.

The above object of the present invention can be achieved by the following constitution.
(1) A drive pulley attached to the end of the crankshaft of the engine, a plurality of accessories provided in the vicinity of the engine, a driven pulley attached to the end of the rotary shaft of each accessory, a drive pulley, An endless belt spanned between each driven pulley, and the rotation of the driving pulley based on the rotation of the crankshaft is transmitted to each driven pulley by the endless belt to rotationally drive the rotating shaft of each auxiliary machine. An automotive accessory drive device, wherein the outer peripheral surface of the drive pulley has an elliptical shape or a polygonal shape.
(2) The outer peripheral surface of the drive pulley has an elliptical shape when the engine is a four-cylinder engine, a substantially triangular shape when the engine is a six-cylinder engine, and a substantially rectangular shape when the engine is an eight-cylinder engine ( 1. Auxiliary machine drive device for automobiles according to 1).

  According to the automotive accessory driving apparatus of the present embodiment, the shape of the outer peripheral surface of the driving pulley is an elliptical shape or a polygonal shape. Fluctuations can be suppressed. As a result, the tension fluctuation of the endless belt can be suppressed, so that the life of the endless belt can be extended, the operation of the apparatus can be stabilized, and the life of the entire apparatus can be extended.

Hereinafter, an embodiment of an automotive accessory driving apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a front view for explaining an embodiment of an automotive accessory driving apparatus according to the present invention.

  As shown in FIG. 1, an automotive accessory drive apparatus 10 of the present embodiment includes a four-cycle four-cylinder engine 11, a drive pulley 12 attached to an end of a crankshaft 11 a of the engine 11, An alternator 13 as an auxiliary machine, an alternator pulley (driven pulley) 14 attached to an end of a rotary shaft 13a of the alternator 13, an auto tensioner 15 as an auxiliary machine for an automobile, and a rotary shaft 15a of the auto tensioner 15 An auto tensioner pulley (driven pulley) 16 attached to the end portion, and an endless belt 17 spanned between the drive pulley 12, the alternator pulley 14, and the auto tensioner pulley 16 are provided.

  Then, the auxiliary driving apparatus 10 for an automobile transmits the rotation of the driving pulley 12 based on the rotation of the crankshaft 11 to the alternator pulley 14 and the auto tensioner pulley 16 by the endless belt 17 to rotate the rotating shaft 13a of the alternator 13. Driving.

  Further, there is no difference between the outer peripheral surface of the crankshaft 11 a of the engine 11 and the inner peripheral surface of the drive pulley 12, and between the outer peripheral surface of the rotating shaft 13 a of the alternator 13 and the inner peripheral surface of the alternator pulley 14. A direction clutch 18 is interposed. That is, the one-way clutch built-in type pulley device is mounted on the crankshaft 11 a and the rotating shaft 13 a of the alternator 13.

  The auto tensioner 15 is disposed between the drive pulley 12 and the alternator pulley 14, and applies an appropriate tension to the endless belt 17 by pressing the auto tensioner pulley 16 attached to the rotation shaft 15 a against the endless belt 17. At the same time, the endless belt 17 is pressed against the outer peripheral surface of the alternator pulley 14 with a predetermined tension.

  In the present embodiment, as shown in FIG. 1, the outer diameter at the point C where the driving pulley 12 where the rotational speed of the driving pulley 12 is low pulls the endless belt 17 is increased, and the rotational speed of the driving pulley 12 is increased. The outer diameter at the point C at which the drive pulley 12 at the place B where the diameter is large pulls the endless belt 17 is reduced. That is, the outer peripheral surface of the drive pulley 12 is formed in an elliptical shape.

  In this embodiment, the outer peripheral surface of the drive pulley 12 is a four-cycle four-cylinder engine, and as shown in FIG. 2, a place A having a low rotational speed and a place B having a large rotational speed are generated every 90 degrees. When the engine 11 is a 6-cylinder engine, a place A having a low rotational speed and a place B having a large rotational speed are generated every 60 degrees, so that the engine 11 is formed in a substantially triangular shape. In this case, a place A where the rotational speed is low and a place B where the rotational speed is high occur every about 45 degrees, and therefore, it is formed in a substantially rectangular shape.

  In the automotive accessory driving apparatus 10 configured as described above, the pull-in amount of the endless belt 17 per minute time at the place A where the rotational speed of the drive pulley 12 is low and the place B where the rotational speed of the drive pulley 12 is high. Since the pull-in amount of the endless belt 17 per minute time is substantially equal, fluctuations in the tension of the endless belt 17 are suppressed.

  As described above, according to the automotive accessory driving apparatus 10 of the present embodiment, the shape of the outer peripheral surface of the drive pulley 12 is elliptical, so that even if there is a rotational fluctuation of the engine 11, the drive pulley 12 The fluctuation in the amount of the endless belt 17 drawn in can be suppressed. Thereby, since the tension | tensile_strength fluctuation | variation of the endless belt 17 can be suppressed, while the lifetime of the endless belt 17 can be extended, the operation | movement of the apparatus 10 can be stabilized and the lifetime of the whole apparatus 10 can be extended. .

The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.
For example, in this embodiment, the case where the present invention is applied to an automotive accessory driving device in which one endless belt is stretched between one driving pulley and a plurality of driven pulleys is illustrated. Without being limited thereto, the present invention may be applied to an automotive accessory driving device in which a plurality of endless belts are spanned between a plurality of driving pulleys and a plurality of driven pulleys.

It is a front view for demonstrating one Embodiment of the auxiliary machine drive device for motor vehicles based on this invention. It is a graph showing the relationship between the rotational speed of the crankshaft and the crank phase when the 4-cycle 4-cylinder engine is rotated at a constant speed. It is a front view for demonstrating the conventional auxiliary machine drive device for motor vehicles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Auxiliary machine drive device for motor vehicles 11 Engine 11a Crankshaft 12 Drive pulley 13 Alternator 13a Rotating shaft 14 Alternator pulley (driven pulley)
15 Auto tensioner 15a Rotating shaft 16 Auto tensioner pulley (driven pulley)
17 Endless belt 18 One-way clutch

Claims (2)

A drive pulley attached to the end of the crankshaft of the engine, a plurality of auxiliary machines provided in the vicinity of the engine, a driven pulley attached to the end of the rotary shaft of each auxiliary machine, and the drive pulley; An endless belt spanned between each driven pulley,
An automotive accessory driving device that transmits the rotation of the driving pulley based on the rotation of the crankshaft to each driven pulley by the endless belt, and rotationally drives the rotating shaft of each accessory,
An auxiliary driving apparatus for an automobile, wherein an outer peripheral surface of the driving pulley is formed into an elliptical shape or a polygonal shape.   The outer peripheral surface of the drive pulley has an elliptical shape when the engine is a four-cylinder engine, a substantially triangular shape when the engine is a six-cylinder engine, and a substantially rectangular shape when the engine is an eight-cylinder engine. Item 2. The auxiliary machine driving device for automobile according to Item 1.

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