JPS63289224A - Alternator for internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce the rotational fluctuation of an engine by linking a flywheel to the shaft of an alternator in the low speed area of the engine so that the moment of inertia of the flywheel provided in a crankshaft increases virtually. CONSTITUTION:When an engine rotates, the pulley 12 of an alternator 1 rotates through a V-belt 23 and it follows that the disc 11A of an electromagnetic clutch 11 performs accelerative rotation together with a shaft 7. When a control unit 17 judges based on a detection signal from an engine speed sensor 18 that the engine is in an idle state or the like, an electromagnetic coil 11D is energized so as to generate magnetic force, Then, a clutch plate 11d is sucked against a spring 11B so as to make it stick to the web 10d of a flywheel 10. As a result, the flywheel 10 and the V-belt 23 function as dynamic dampers so that reaction force against the engine can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an alternator for an internal combustion engine, and more particularly to an alternator for an internal combustion engine that is designed to stabilize engine rotation in a low-speed rotation range including idling.

(Prior art and its problems) As is well known, lowering the engine speed during idling has the effect of reducing fuel consumption, but it increases the rotational fluctuation and deteriorates the idling stability.Improving the stability at 0 rotation As a countermeasure for this, there is a method of increasing the mass of the flywheel of the crankshaft to increase the moment of inertia of the flywheel.

However, as shown in FIG. 3, when the flywheel 32 attached to the crankshaft 31 is made larger, the weight of the engine 33 increases, and due to an increase in the moment of inertia, the reaction force of torque fluctuation due to the engine cycle, that is, the engine The reaction forces A, A'' which the engine 33 receives from the vehicle body 34 at the mounting portion of the engine 33 become large.In other words, the problem arises that the excitation force applied to the vehicle body 34 becomes large and the vehicle body vibration becomes large.

SUMMARY OF THE INVENTION An object of the present invention is to provide an alternator for an internal combustion engine that is capable of stabilizing engine rotation in a low-speed rotation range including when the engine is idling, and suppressing vehicle body vibration.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an alternator for an internal combustion engine which is rotated at an increased speed by a crankshaft via a belt. a supported flywheel, an engagement means for engaging the shaft of the alternator and the flywheel so as to be able to come into contact with and separate from each other, and when the engagement means is disengaged, the flywheel follows the rotation of the shaft of the alternator. An alternator for an internal combustion engine is provided, characterized in that the alternator is provided with a follower means for causing the alternator to move.

(Function) In the low-speed rotation range including when the engine is idling, the engagement means is activated to connect the flywheel to the shaft of the alternator, and the moment of inertia of the flywheel, which is rotated at increased speed by the rotation of the crankshaft, is transferred to the crankshaft. is added to the moment of inertia of the flywheel. This increases the moment of inertia of the flywheel of the crankshaft, thereby stabilizing the rotation. Further, due to the rotation of the crankshaft and the flywheels of the alternator, a phase shift occurs in the forces acting on the mount portion of the engine, thereby reducing vibration of the vehicle body.

Moreover, when the engagement means is disconnected, the flywheel of the alternator is rotating following the rotation of the shaft of the alternator by the following means, and the impact is reduced when the flywheel is joined to the shaft of the alternator.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

1 and 2, an alternator 1 includes a front bracket 2 and a rear bracket 3, which are outer frames, a stator 4, and a rotor 5.

Stator 4 includes front bracket 2 and rear bracket 3
are interposed between them, and are secured together by bolts 6. The rotor 5 is rotatably housed within the stator 4, and the shaft 7 of the rotor 5 is supported at both ends by the front bracket 2 and the rear bracket 3 through bearings 8.9.

A flywheel 10 is attached to one end of this shaft 7. The electromagnetic clutch 11 and the boot IJ 12 are fitted in order from the front bracket 2 side, and are fixed by a nut 13 so as not to be movable in the axial direction.

The flywheel 10 is made of a conductive magnetic member 1, for example, an iron member, and has a monogonal shape when viewed in cross section, and has a central boss 10.
It is rotatably fitted to the shaft 7 via a bearing 14 fitted into the shaft hole 10b of a. Further, a large number of blades 10c are formed at predetermined intervals in the circumferential direction on the peripheral edge of the end surface of the flywheel 10 facing the front bracket 2.

The electromagnetic clutch 11 is connected to the web 10 of the flywheel 10.
a disk 11A disposed facing the end surface lOe of d;
Spring IIB, clutch plate 11C, and web 10
An electromagnetic coil IID disposed facing the end surface 10f of d.
It consists of The disk IIA is non-rotatably fixed to the shaft 7 together with the support member 15, and the clutch plate 11C has an annular shape, and a plurality of springs IIB are attached to the peripheral edge of the end surface 11a of the disk 1.1A facing the web 10d.
Moreover, it is attached concentrically with the shaft 7. This clutch plate 11C is made of a magnetic member such as iron. On the other hand, the electromagnetic coil LID is housed in a case 16 and fixed to the end surface 2a of the front bracket 2 concentrically with the shaft 7 and at a position facing the clutch plate 11G via the flywheel 10.

This electromagnetic coil IID is connected to a control unit 17. The control unit) 17 energizes or deenergizes the electromagnetic coil IID based on the speed signal input from the engine rotational speed sensor 18. When the engine rotational speed is below a predetermined number of rotations, the control unit 17 energizes or deenergizes the electromagnetic coil ILD. 1a magnetic coil IID when the specified rotation speed is exceeded
Deactivate.

When the electromagnetic coil IID is energized, it attracts the clutch 111G against the spring force of the spring IIB, and causes the clutch 111G to be firmly attracted to the web 10d of the flywheel 10.

Further, a subring II is attached to the end surface 11a of the disk IIA.
A support member 15 is integrally fixed to the disk IIA at a position closer to the center than the clutch plate 11C and the clutch plate 11C. A ring-shaped magnet 7) 19 is fixed to the peripheral edge of the end face of the support member 15 facing the web 10d, facing the web 10d with a predetermined gap.

The pulley 12 consists of a first member 12A and a second member 12B. The first member 12A is approximately dish-shaped and has a disk I
The open end 12a facing IA is pressed against the end surface 11b of the disk IIA. Further, the end surface 12b is a tapered surface from the center toward the end surface 12a. The second member 12B is also formed similarly to the first member 12A, and these first. The pulley 12 is formed by welding the second members 12A and 12B at their central portions by, for example, spot welding, and a V-groove is formed by the end surfaces 12b and 12C.

The alternator 1 configured as described above is connected to the engine 2.
The front bracket 2 and the rear bracket 3 are attached to a support portion 20a shown by a two-dot chain line provided on one side wall of the front bracket 2 and a rear bracket 3 via flanges 2b and 3a, respectively. A V-belt 23 is wound between the pulley 12 of the alternator 1 and the pulley 22 of the crankshaft 21, and the driving force of the crankshaft 21 is transmitted to rotate the shaft 7 of the alternator 1 at an increased speed.

By the way, the kinetic energy E of the flywheel is E=%
XIXω2...(al) Here, ■ represents the moment of inertia, and ω represents the angular velocity.

Also, the angular velocity of the pulley 12 of the alternator 1 is set to ω3. Let the angular velocity of the pulley 22 of the crankshaft 21 be ω2,
If ω1/ω8 is defined as the speed increasing ratio, ω1=(speed increasing ratio)×ω, . . . mountain).

Therefore, when the moment of inertia ■ acts on the flywheel 10 of the alternator 1, this flywheel 10
From the above equations (5) and (b), the kinetic energy E1 of E+-! /GXI+Xω1N +=%x I, x (speed increasing ratio) 8×ω-. In other words, on the flywheel 24 of the crankshaft 21, ■Yo-! It is possible to obtain the same effect as when a moment of inertia of 1×(speed increase ratio) 8 is applied.

The speed increasing ratio is generally a value of about 2 to 3. Therefore, when it is desired to increase the moment of inertia (Is) of the flywheel 24 of the crankshaft 21, the increase amount ΔIt of the moment of inertia is 1/4 to 1/9 This means that the moment of inertia of the alternator 1 may be shared by the flywheel 10 of the alternator 1.

Thereby, the size of the flywheel 10 of the alternator 1 is set based on the amount of inertia moment to be added to the flywheel 24 of the crankshaft 21 in addition to the inertia moment of the flywheel 24 itself, and the aforementioned speed increase ratio. be done.

The action will be explained below.

When the crankshaft 21 of the engine 20 rotates, the V-belt 23, which is wound around the pulley 22 of the crankshaft 21, causes the alternator 1 to boom! J12 rotates, thereby causing the disk IIA of the electromagnetic clutch 11 to rotate at an increased speed together with the shaft 7.

When the control unit 17 determines that the engine 20 is in an idle state or in a low speed rotation region based on the detection signal from the engine rotation speed sensor 18,
The electromagnetic coil IID is energized to generate magnetic force, and the clutch plate 11C is attracted against the spring force of the spring IIB to be strongly attracted to the web 10d of the flywheel 10. As a result, the flywheel 10 rotates together with the disk IIA of the electromagnetic clutch 11.

At this time, as shown in FIG. 2, the engine 20 generates reaction forces B, B'' based on the rotation of the flywheel 24 of the crankshaft 21 at the mount portion, reaction forces c based on the rotation of the flywheel 10 of the alternator 1, c' and car body 2
5, but the directions in which these reaction forces B, B' and c, c' act are different from each other. In addition, since the V-belt 23 is not a completely rigid body, a spring structure is formed between the flywheel 10 and the boot IJ 22, and the engine 2
A shift occurs in the timing (phase) of the action of the reaction forces B, B' and the reaction force C9C'' at the mount portion of the mount.

Thereby, the flywheel 10 and the V-belt 23 function as a dynamic damper, the reaction force to the engine 20 is reduced, and the engine rotation in the low-speed rotation range including idling is stabilized.

In the middle/high speed rotation range of the engine 20, the control unit 17 deenergizes the electromagnetic coil lID, and the flywheel 10 is rotated 1if by the spring force of the spring IIB.
It is separated from the clutch plate 11C of the T-clutch 11 and can rotate freely. In this state, the state is the same as if the flywheel 10 were not provided in the alternator 1. On the other hand, the magnetic flux generated by the magnet 19 penetrates the web 10d of the flywheel 10, and since the magnet 19 rotates integrally with the disk IIA, there is a difference in rotational speed between the magnet 19 and the flywheel 10. arise. Due to this rotational speed difference, the web 10d
The magnetic flux penetrating through the disk I
Rotates following the rotation of IA. Further, when the flywheel 10 rotates, each blade 10c formed on the flywheel 10 blows air to the alternator 1 to cool the alternator l.

When the engine rotation is decelerated from a medium/high speed range to a low speed range, the flywheel 10 is rotating as described above, and there is not much difference in rotational speed between the flywheel 10 and the disk IIA of the electromagnetic clutch 11. clutch plate 11c
The shock caused when the web 10d is attracted to the web 10d is reduced by the synchronization effect.

Furthermore, since the clutch plate 11C of the electromagnetic clutch 11 is disconnected from the flywheel 10 in the medium/high speed rotation range of the engine 20, the flywheel IO of the alternator 1 does not become an extra engine load. Even if the engine rotational speed suddenly increases due to sudden acceleration and moves into the medium/high rotational range, the response when the engine rotational speed increases will not deteriorate.

Furthermore, since each blade 10c of the flywheel 10 acts as a resistance when the flywheel 10 rotates, the rotation of the flywheel 10 in the engine medium/high speed rotation region follows the increase in rotation of the disk 11A of the electromagnetic clutch 11. The rotational speed of the flywheel 10 does not increase to the level of the disk IIA, and unnecessary high-speed rotation of the flywheel 10 is prevented. Therefore, in the engine high-speed rotation region, excess load is prevented from being applied to the bearing 14 due to the gyroscopic effect or engine vibration, and a decrease in the durability of the bearing 14 is prevented.

Furthermore, as described above, the flywheel 10 of the alternator 1 can be of a small size, and by providing the flywheel 10, the flywheel 24 of the crankshaft 21 can be made smaller, which increases the weight of the engine itself. can be suppressed.

In this embodiment, electromagnetic force due to eddy current is used to achieve synchronization between the flywheel 10 and the disk IIA of the electromagnetic clutch 11, but instead of the magnet 19, other fluid couplings such as air may be used. may be used, and at the same time the alternator 1 may be cooled by this fluid coupling.

(Effects of the Invention) As explained above, according to the present invention, in an alternator of an internal combustion engine that is rotated at an increased speed by a crankshaft via a belt, a flywheel rotatably supported on the shaft of the alternator; The shaft of the alternator and the flywheel are provided with an engaging means for engaging the shaft of the alternator and the flywheel in a contact/transferable manner, and a following means for causing the flywheel to follow the rotation of the shaft of the alternator when the engaging means is disconnected. With this configuration, by adding the moment of inertia of the alternator flywheel to the moment of inertia of the crankshaft flywheel in the low-speed rotation range including idle, it is possible to substantially increase the moment of inertia of the crankshaft flywheel. This makes it possible to reduce engine rotational fluctuations. In addition, the directions of the forces acting on the engine mounts due to the rotation of the crankshaft and alternator flywheels are different from each other, and the forces acting on the mounts are out of phase, which greatly suppresses vehicle body vibration. It becomes possible to do so.

Furthermore, when the engagement means is disconnected, the flywheel of the alternator rotates following the rotation of the shaft of the alternator by the following means, so when the engagement means engages the flywheel of the alternator, the synchronization action This has the effect of reducing the impact.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of an alternator for an internal combustion engine according to the present invention, FIG. 2 is a schematic diagram showing the direction of force acting on the mount portion of the internal combustion engine in FIG.
The figure is a schematic diagram showing the direction of force acting on the mount portion of a conventional internal combustion engine. 1... Alternator, 7... Shaft, 10...
Flywheel, 11... Electromagnetic clutch, 14...
Bearing, 19... Magnet, 21... Crankshaft, 23... V-belt, 24... Crankshaft flywheel. Applicant Mitsubishi Motors Corporation Agent Patent Attorney Kan Nagato Santsutsu Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In an alternator of an internal combustion engine that is rotated at increased speed by a crankshaft via a belt, a flywheel is rotatably supported on a shaft of the alternator, and the shaft of the alternator and the flywheel are connected to each other so as to be able to come into contact with and separate from each other. An alternator for an internal combustion engine, comprising an engaging means for causing the flywheel to follow the rotation of the shaft of the alternator when the engaging means is disengaged.