JP2017180545A - Flywheel of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improvement measure which is simple in s structure, excellent in versatility, and superior in terms of a function, in a balancer device for canceling an inertia force or an inertia couple of a piston.SOLUTION: A plurality of planetary gears 16 are arranged at an inner face of a flywheel 11 at equal intervals in a peripheral direction. The planetary gears 16 are geared with inner tooth gears 13 fixed to the flywheel 11, and outer tooth gears 14 rotatably held to a crankshaft 1. When one of pistons 22 is located at a top dead point, the center of gravity 21 of the flywheel 11 as a whole is located immediately below a rotating shaft axial core 20. Since a balancer device uses the flywheel 11, a structure is simple, and versatility is excellent. Since the planetary gears 16 are located outside the crankshaft 1, the balance device exerts a high-weight function though it is reduced in size, and can appropriately cancel an inertia force or an inertia couple of the piston 22.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a flywheel for an internal combustion engine.

  In an internal combustion engine that converts the reciprocating motion of the piston into rotation of the crankshaft, a counterweight is provided on the crank arm to reduce the inertial force or inertial couple, but the inertial force or inertial couple of the piston is only with the counterweight. In some cases, a balancer device may be provided.

  Conventionally, as disclosed in, for example, Patent Literature 1, this balancer device is provided with a balance shaft parallel to the crankshaft in the cylinder block, and the crankshaft and the balance shaft are interlocked with a gear. The balance shaft decenters the center of gravity of the weight from the rotational axis, and the inertial force or inertial couple of the crankshaft is canceled out by the inertial force or inertial couple generated by the eccentricity.

JP 2006-132409 A

  There are several problems with the conventional measures for providing a balance axis. For example, the balance shaft and the interlocking gear must be arranged in the crankcase so as not to hit the members such as the crank arm, but the crankcase should be as compact as possible, so the design is very troublesome, There was a problem that assembly took a lot of time and effort.

  In addition, the balance shaft has a limitation that the outer diameter and length cannot be increased because the installation space is limited. Then, the inertial force or inertial couple sufficient to cancel out the inertial force or inertial couple of the crankshaft. There is also concern that it cannot be granted.

  The present invention has been made to improve the current situation.

In the present invention, a flywheel fixed to one end of a crankshaft is provided with a balancer function. That is, according to the present invention, a planetary gear serving as a balancer (counterweight) that cancels the inertia force or inertia couple of a piston on one side of a flywheel rotates in conjunction with the rotation of the crankshaft while rotating on the axis of the crankshaft. Attached to revolve around,
It is

  In the present invention, the flywheel needs to be provided with a gear that meshes with the planetary gear in order to allow rotation and revolution of the planetary gear. However, an internal gear and an external gear are provided, and the planetary gear is connected to the internal gear. A system sandwiched between a gear and an external gear is preferable. In this case, it is preferable that the internal gear is fixed to the flywheel and the external gear is an idle gear that is rotatably held by the crankshaft (the external gear is idled with respect to the crankshaft 1).

  In the present invention, the number of planetary gears can be arbitrarily set, but it is preferably set to 3 or more in order to prevent the planetary gear itself from causing inertial force or inertial couple. The planetary gear and the gear meshing with the planetary gear may be spur gears, but it is preferable to employ a helical gear that is smoothly meshed and excellent in quietness.

  In the present invention, the planetary gear functions as a balancer (weight) that cancels the inertia force or inertia couple of the crankshaft. That is, when the piston is at the top dead center, the planetary gear movement (revolution) is set so that the planetary gear (or the center of gravity of the planetary gear group) is located at the bottom dead center. A smooth rotation of the crankshaft can be realized by canceling the force or inertia couple.

  In the case of a multi-cylinder internal combustion engine, a plurality of pistons sequentially shift to top dead center, but in the present invention, by making the revolution state of the planetary gear correspond to the movement of each piston, as a counterweight for each piston Can function. That is, for example, in a three-cylinder internal combustion engine, three pistons move to top dead center at a rotation interval of 120 °, but the position of the planetary gear on the flywheel or the center of gravity of the planetary gear group By changing the wheel by 120 ° with respect to one rotation of the wheel, the planetary gear can function as a counterweight for each piston.

  And in this invention, since the flywheel which is a required member of an internal combustion engine is utilized for a balancer apparatus, there is no space problem and versatility is high. More specifically, both sides of the flywheel are generally concave and often have a dead space, but the present invention can effectively utilize this dead space for the arrangement of planetary gears, so that the size of the internal combustion engine can be increased. There is no invitation.

  In an automobile internal combustion engine, a transmission member is usually fixed to the outer surface of the flywheel opposite to the cylinder block. Therefore, the planetary gear is provided on the inner surface facing the cylinder block. Is preferred. In this case, it is very easy to fit the planetary gear within the thickness of the flywheel, so that the size of the internal combustion engine is not increased.

  Furthermore, since the planetary gear of the present invention is arranged outside the outer periphery of the crankshaft, it exhibits a high counterweight effect even with a small weight. Accordingly, the crankshaft can be smoothly rotated by accurately canceling the inertial force or the inertial couple of the crankshaft.

  Furthermore, although the flywheel has a certain amount of weight due to its function, in the present invention, the planetary gear can also be used as a part of the flywheel. . Therefore, the internal combustion engine can be reduced in weight as compared with the conventional structure provided with the balance shaft, and as a result, the fuel consumption can be improved.

  Further, when the balance shaft is provided, there is a problem of lubrication of the bearing portion. However, in the present invention, lubrication is unnecessary or can be easily performed. This is also beneficial.

It is a vertical side view of the principal part. FIG. 2A is a view of a flywheel viewed from the II-II viewing direction of FIG. 1, and FIG. 2B is a schematic diagram showing movement of a piston and a crankshaft of a three-cylinder internal combustion engine.

  Next, an embodiment of the present invention will be described with reference to the drawings. The crankshaft 1 has front and rear end journals 2 and a plurality of intermediate journals 3, and the end journal 2 and the intermediate journal 3 are connected by a pair of crank arms 4 and a crankpin 5. The cylinder block 6 is formed with bearings 7 and 8 corresponding to the journals 2 and 3, the end journal 2 is rotatably held by the end bearing 7 with an end cap 8, and the intermediate journal 3 is an intermediate journal 3 A cap 8 is rotatably held on the intermediate bearing 7.

  One end (rear end) of the crankshaft 1 is exposed to the outside of the cylinder block 6, and the flywheel 11 is fixed to the exposed portion with bolts 11a. Of the inner and outer surfaces of the flywheel 11, the inner surface facing the cylinder block 6 is formed with a recess 12 located close to the outer periphery, and the internal gear 13 constituting the balancer device is fixed to the recess 12. Has been.

  On the other hand, an external gear 14 corresponding to the internal gear 13 is mounted on the exposed portion of the crankshaft 1 through a bearing 15 so as to be relatively rotatable. Between the internal gear 13 and the external gear 14, In addition, three planetary gears 16 meshed with both the gears 13 and 14 are arranged at equal intervals in the circumferential direction.

  Each planetary gear 16 is provided with an outward boss 17, and this boss 17 is slidably fitted into an annular groove 18 formed in the recess 12 of the flywheel 11. A ring plate 19 for preventing the planetary gear 16 from being punched out is fixed to the inner surface of the flywheel 11.

  While the internal gear 13 rotates integrally with the flywheel 11, the external gear 14 rotates freely with respect to the crankshaft 1, so that each planetary gear 16 rotates while the flywheel 11 rotates. Revolves around the axis of the crankshaft 1. Since the boss 17 of each planetary gear 16 is fitted in the annular groove 18 of the flywheel 11, the revolution of the planetary gear 16 is performed smoothly.

  How much the planetary gear 16 moves in the circumferential direction per one rotation of the crankshaft 1 is determined by the number of teeth of the internal gear 13 and the number of teeth of the planetary gear 16. This embodiment corresponds to a three-cylinder internal combustion engine, and each planetary gear 16 is set to advance by 120 ° when the flywheel 11 rotates once.

  The external gear 14 is a support member that maintains a state in which the planetary gear 16 is engaged with the internal gear 13. Therefore, although not necessarily a gear, if the external gear 14 is used, the planetary gear 16 moves smoothly. It is also possible to fix the external gear 14 to the crankshaft 1 and allow the internal gear 13 to idle with respect to the flywheel 11, but in this case, since the bearing becomes large, the external gear 14 is idled. It is reasonable to let

  In FIG. 2A, two of the three planetary gears 16 are positioned directly above the rotation axis 20 of the crankshaft 1, and the two planetary gears 16 are symmetrical below the rotation axis 20. Is located. Accordingly, the entire center of gravity 21 of the three planetary gears 16 is located directly below the rotation axis 20 and above the center of the two lower planetary gears 16. Accordingly, the center of gravity of the flywheel 11 including the planetary gear 16 as a whole coincides with the center of gravity 21 of the three planetary gears 16 and is located below the rotational axis 20.

  On the other hand, FIG. 2B shows the movement of the three pistons 22, and one piston 22 is at the top dead center. Since there are three cylinders, the movement of the piston 22 is shifted by 120 ° with the rotation of the crankshaft 1, and each time the crankshaft 1 rotates by 120 °, the three pistons 22 sequentially reach the top dead center.

  FIG. 2A shows a state where one piston 22 is at the top dead center. In this state, the entire center of gravity 21 of the flywheel 11 is located below the rotational axis 20. Therefore, the center of gravity 21 of the entire flywheel 11 is in a positional relationship opposite to that of the piston 22 with the rotation axis 20 interposed therebetween. Therefore, the inertia couple of the piston 22 and the inertia couple of the flywheel 11 are balanced. As a result, smooth rotation can be realized without applying centrifugal force to the crankshaft 1.

  When the flywheel 11 rotates, the height of each planetary gear 16 changes, so that the height of the entire center of gravity 21 also changes. However, when any piston 22 is at the top dead center, the three planetary gears 16 are changed. Is always in the positional relationship shown in FIG. 2A, so that a smooth rotation can always be realized.

  And since the flywheel 11 which is a required member of an internal combustion engine is utilized as a structural member of a balancer apparatus, while being able to simplify a structure so much, it is excellent in versatility. Also, processing and assembly are much easier than the conventional balance shaft method. Further, since the planetary gear 16 can be accommodated within the thickness of the flywheel 11, the size of the engine is not increased, and it is compact and does not increase in weight.

  The number of planetary gears 16 need not necessarily match the number of cylinders. Even if the number of planetary gears 16 is three, if the group of planetary gears 16 is advanced by 90 degrees in the circumferential direction, it can correspond to a four-cylinder internal combustion engine. From the viewpoint of stability, 3 or a multiple of 3 is preferable.

  Since the planetary gear 16 also functions as the mass of the flywheel 11, the entire weight including the planetary gear 16 may be set in designing the flywheel 11. For example, the specific gravity of the planetary gear 16 can be made larger than the material of the flywheel 11 by embedding lead in the planetary gear 16. In this case, the planetary gear 16 can be made more compact by reducing the size and thickness.

  If helical gears are employed as the gears 13, 14, 16, the rotation is smooth and noise countermeasures are provided. Moreover, it can be said that the lubrication of the meshing portion between the planetary gear 16 and the internal gear 13 and the external gear 14 can be handled with grease. Lubrication of the bearing 15 of the external gear 14 can also be handled with grease. Therefore, the lubrication means can be omitted or greatly simplified. This embodiment is also advantageous in this aspect.

  The present invention can actually be embodied in a flywheel. Therefore, it can be used industrially.

1 Crankshaft 11 Flywheel 13 Internal Gear 14 External Gear 15 Bearing 16 Planetary Gear

Claims (1)

A flywheel fixed to one end of the crankshaft,
A planetary gear serving as a balancer that counteracts the inertial force or inertial couple of the piston is attached to one surface thereof so as to revolve around the axis of the crankshaft while rotating in conjunction with the rotation of the crankshaft.
Internal combustion engine flywheel.

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