JPH06294446A - Flywheel - Google Patents

Abstract

(57) [Abstract] [Purpose] Stabilize the rolling trajectory of the damper mass that performs centrifugal pendulum motion while rolling to obtain a good rotation fluctuation reduction effect and prevent the generation of impact noise. In a flywheel having a damper mass 5 that performs a pendulum motion that bulges radially outward of a flywheel body 1 while rolling along a rolling surface 2a in a rolling chamber 2, rotation of the pendulum motion of the damper mass 5 The center axis C _D is inclined with respect to the rotation center axis C _F of the flywheel main body 1 with both the axes C _D and C _F existing in the same plane. The inclination angle θ is set to such an extent that the rolling path of the damper mass 5 can be stabilized while keeping the frictional force between the damper mass 5 and the side surface 2b of the rolling chamber 2 within an allowable range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational fluctuation reducing flywheel for reducing constant order rotational fluctuation generated in an internal combustion engine such as a vehicle engine, and more particularly to a damper mass that performs centrifugal pendulum motion while rolling. In the flywheel including the above, the rolling path of the damper mass is stabilized so that a good rotation fluctuation reducing effect can be obtained.

[0002]

2. Description of the Related Art A driving force of an internal combustion engine such as an engine of a vehicle is obtained by converting a combustion force into a rotational force by a crank mechanism. Occurs, this rotation fluctuation vibrates,
It causes noise. For example, in the case of a 4-cycle 4-cylinder engine, the rotational fluctuation due to the secondary torque fluctuation becomes a problem, and in the case of the 6-cylinder engine, the rotational fluctuation due to the tertiary torque fluctuation becomes a problem.

As a conventional flywheel for reducing the rotation fluctuation due to such torque fluctuation, Japanese Patent Application No. 3-121037 and Japanese Patent Application No. 3-274108 proposed by the present applicant have been proposed. There are some written in the book. In these conventional flywheels, a rolling chamber is formed in the flywheel body, and a damper mass is housed in the rolling chamber so that the damper mass can roll freely. It is intended to reduce the rotational fluctuation of the shaft and the like by the periodic fluctuation of the position of the center of gravity accompanying the pendulum motion of the damper mass.

FIG. 5 is a cross-sectional view showing a conventional flywheel structure provided with a freely rotatable damper mass. In a rolling chamber 2 formed on the peripheral surface of a disk-shaped flywheel body 1, a cylinder is provided. The portion accommodating the roller-shaped damper mass 5 is shown. The rotation center axis C _D of the centrifugal pendulum motion of the damper mass 5 was parallel to the rotation center axis C _F of the flywheel body 1.

[0005]

However, in the conventional flywheel as shown in FIG. 5, in order to ensure a smooth rolling motion of the damper mass 5, the side surface of the rolling chamber 2 and the lateral surface of the damper mass 5 are secured. The size of the damper mass 5 in the thickness direction was selected so that there is a gap between the damper mass 5 and the flywheel because the damper mass 5 does not actively restrain the trajectory of the damper mass 5 due to some disturbance. When the body mass 1 moves away from the rotating surface, the damper mass 5 rolls while meandering as shown in FIG. 6, and as a result, the damper mass 5 behaves largely outside the desired centrifugal pendulum motion, A sufficient effect of reducing the rotational fluctuation cannot be obtained. Further, when the damper mass 5 meanders, the damper mass 5 collides with the side surface of the rolling chamber 2 and an impact sound is generated, which causes deterioration of the noise level.

The present invention has been made by paying attention to the problems to be solved by such a conventional technique, and for reducing the rotational fluctuation capable of stabilizing the rolling trajectory of the damper mass with a simple structure. The purpose is to provide a flywheel.

[0007]

In order to achieve the above object, the present invention provides a pendulum motion that expands radially outward of the flywheel body while rolling in a rolling chamber formed in the flywheel body. In a flywheel accommodating a roller-shaped damper mass, the rotation center axis of the pendulum motion of the damper mass is tilted with respect to the rotation center axis of the flywheel main body in a state where both axes are in the same plane. .

[0008]

When the flywheel main body rotates and the rotational fluctuation is transmitted to the flywheel main body, the roller-shaped damper mass accommodated in the rolling chamber makes a centrifugal pendulum motion while rolling. Since the central axis of rotation is inclined with respect to the central axis of rotation of the flywheel body, the direction of the centrifugal force generated in the damper mass and the rolling surface of the pendulum motion of the damper mass do not intersect perpendicularly. A component force in the biasing direction is generated on the side surface of the moving chamber, so that the damper mass rolls while always being in contact with one side surface of the rolling chamber.

As a result, the rolling path of the damper mass becomes stable, and the damper mass does not collide with the side surface of the rolling chamber during rolling.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing a first embodiment of the present invention, and FIG. 1 is a partially cutaway front view of a flywheel main body 1,
2 is a sectional view taken along the line AA of FIG. First, the configuration will be described. The disc-shaped flywheel main body 1 has a mounting flange portion 1a used at the time of mounting on a rotary drive system in its central portion, and has a circumferential surface in its circumferential direction. Eight rolling chambers 2, ..., 2 of the same shape are formed at equal intervals.

The rolling chambers 2, ..., 2 are closed spaces formed by recessing the circumferential surface of the flywheel body 1 and sealing the opening side of the recesses with a thin plate ring-shaped cover 4. The cylindrical roller-shaped damper mass 5 is rotatably accommodated inside thereof. Each rolling chamber 2,
The shape of 2 ..., especially the curvature of the radially outer surface which is the rolling surface of the damper mass 5 is selected so that the trajectory of the pendulum motion of the damper mass 5 satisfies the theory of the centrifugal pendulum.

Specifically, the mass of the damper mass 5 is m _d ,
When the inertia ratio of the damper mass 5 is I _d , the radius of the damper mass 5 is r _d , and the rotational fluctuation order generated in the rotary drive system to which the flywheel main body 1 is attached is n, the damper mass 5 starts from the rotation center O _{1 of the} flywheel main body. and distance R to the fulcrum O ₂ of the pendulum movement, the ratio R / L of the distance L from the fulcrum O ₂ of pendulum movement of the damper mass 5 to the center of gravity G of the damper mass ^{5, R / L = n 2} {1 + I d / The relationship may be set to (m _d · r _d ² )}. Since the present embodiment has a plurality of damper masses 5, both mass m _d and inertial performance rate I _d are total values of the plurality of damper masses 5.

Further, the dimension of the rolling chamber 2 in the rolling direction of the damper mass 5 is determined by the maximum value of the amplitude of the rotational fluctuation generated in the rotary drive system, and the maximum amplitude angle φ of the pendulum motion of the damper mass 5 on one side.
In consideration of the above, the damper mass 5 does not collide with the end surface of the rolling chamber 2 even if it rolls in the range of the maximum amplitude angle. Then, in the present embodiment, as shown in FIG. 2, the concave portion of the flywheel main body 1 forming the rolling chamber 2 is formed on the bottom surface (rolling chamber) with respect to the rotation center axis C _F of the flywheel main body 1. Two
The radially inner part of the one side surface 2b) is obliquely recessed in a direction lower than the outer side.

Therefore, the rolling surface 2a of the rolling chamber 2 is inclined so that the end portion on the side surface 2b side is located radially outward, and the center axis C of rotation of the centrifugal pendulum motion of the damper mass 5 is increased. _D is inclined by an angle θ with respect to the rotation center axis C _F of the flywheel body. However, the rotation center axes C _D and C
_The rotation center axis C _D exists in the same plane as the rotation center axis C _F even in a tilted state so that _F is not in a twisted position.

Next, the operation of this embodiment will be described. For example, a crankshaft of a vehicle engine will have a secondary rotational fluctuation in the case of a 4-cylinder engine and a tertiary rotational fluctuation in the case of a 6-cylinder engine. And if the flywheel according to the present embodiment is attached to such a crankshaft,
Due to the centrifugal force generated by the rotation of the flywheel main body 1 and the rotational fluctuation, the damper mass 5 rolls along the rolling surface 2a and performs a centrifugal pendulum motion that swells radially outward. As a result of the selection as described above, the pendulum motion of the damper mass 5 absorbs the rotational fluctuation, that is, has a phase opposite to the rotational fluctuation that occurs in the crankshaft, so such rotational fluctuation is reduced and the vibration level is reduced. The noise level is reduced.

When the damper mass 5 makes a centrifugal pendulum motion, a centrifugal force F as shown in FIG.
However, since the rolling surface 2a of the rolling chamber 2 is inclined by the angle θ in the above-mentioned direction, the component force f in the direction of pressing the damper mass 5 to the side surface 2b of the rolling chamber 2 is reduced. Occurs. Therefore, the damper mass 5 in rolling always comes into contact with the one side surface 2b as shown in FIG. 2, and the pendulum motion is made along the side surface 2b. Therefore, the damper mass 5 does not meander while swinging as shown in FIG. 6, but behaves like a desired centrifugal pendulum motion, and a good rotation fluctuation reducing effect can be obtained. Since the damper mass 5 does not collide with the side surfaces 2b and 2c of the rolling chamber 2 during rolling, deterioration of the noise level is also prevented.

However, if the component force f is too large, the frictional force between the damper mass 5 and the side surface 2b of the rolling chamber 2 becomes excessive, so it is not preferable to make the inclination angle θ too large. Specifically, if 0 ° <θ ≦ 5 °, the rolling trajectory of the damper mass 5 can be stabilized while keeping the frictional force within the allowable range. That is, if θ is slightly larger than 0 °, the component force f becomes a sufficient trajectory restraining force of the damper mass 5, and if θ is at most about 5 °, the component force f is f = 0.0.
This is because it is about 10% of 9 F and the centrifugal force F, and the frictional force generated thereby does not interfere with the pendulum motion.

FIG. 3 is a view showing a second embodiment of the present invention and is a sectional view of a portion equivalent to FIG. 2 of the first embodiment. It should be noted that the same reference numerals are given to the same members and parts as those in the configuration of the first embodiment, and the duplicated description will be omitted. In this embodiment, the inclination relationship between the rotation center axis C _D of the pendulum motion of the damper mass 5 and the rotation center axis C _F of the flywheel body 1 is reversed from that of the first embodiment, so that the rolling chamber 2 Of the rolling surface 2a is inclined so that the end portion on the side of the other side surface 2c is located radially outward.

The cover 4 of the flywheel body 1
Is formed so that the normal vector N thereof is parallel to the rotation center axis C _D, and the shape of the cover 4 also matches the surface shape of the flywheel body 1 to which it is fixed. And is inclined by an angle θ. With such a configuration, the damper mass 5 rolls along the other side surface 2c of the rolling chamber 2 by the action equivalent to that of the first embodiment, and thus the damper mass 5 is equivalent to that of the first embodiment. The effect is obtained.

In the structure of this embodiment, since the damper mass 5 makes a pendulum motion along the other side surface 2c, the finishing accuracy of the side surface 2c is a problem to ensure smooth rolling of the damper mass 5. However, since the side surface 2c is formed on one surface of the cover 4 which is separate from the flywheel body 1, there is an advantage that the finishing accuracy can be easily increased. FIG. 4 is a view showing a third embodiment of the present invention and is a sectional view of a portion equivalent to FIG. 2 of the first embodiment. It should be noted that the same reference numerals are given to the same members and parts as those in the configuration of the first embodiment, and the duplicated description will be omitted.

The configuration of this embodiment is substantially the same as that of the second embodiment described above, except that the inner side of the rolling chamber 2 has a radially inner portion 2d whose opening side is the center of the flywheel body 1. The point is that it is inclined so that it approaches the side. With such a configuration, since the opening side of the rolling chamber 2 becomes wide, there is an advantage that the mold can be easily pulled out when the flywheel main body 1 is cast.

[0022]

As described above, according to the present invention,
Since the rotation center axis of the pendulum motion of the damper mass is tilted with respect to the rotation center axis of the flywheel main body in a state where both the axes are in the same plane, the rolling trajectory of the damper mass can be stabilized, There is an effect that a good rotation fluctuation reducing effect can be obtained, and at the same time, the generation of impact noise can be prevented and the noise level can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a flywheel showing a configuration of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view showing a configuration of a second embodiment.

FIG. 4 is a sectional view showing the structure of a third embodiment.

FIG. 5 is a cross-sectional view showing a conventional configuration.

FIG. 6 is a diagram illustrating a conventional problem.

[Explanation of symbols]

1 Flywheel main body 2 Rolling chamber 4 Cover 5 Damper mass C _D Rotation center axis of pendulum motion of damper mass C _F Rotation center axis of flywheel body

Claims (1)

[Claims] 1. A flywheel in which a roller-shaped damper mass is housed in a rolling chamber formed in the flywheel main body so that the pendulum swells radially outward of the flywheel main body while rolling, and a pendulum of the damper mass is provided. A flywheel characterized by inclining a rotation center axis of motion with respect to a rotation center axis of the flywheel main body in a state where both the axes are in the same plane.