JPH01312246A - Constant order type dynamic damper - Google Patents

Abstract

PURPOSE:To absorb torque fluctuation caused in the case of low speed rotation, by providing an interlocking mechanism between a ring-shaped weight secured to an axis of rotation and a fly-weight, and relating the axial movement of the ring-shaped weight and the radial movement of the fly-weight to each other. CONSTITUTION:A ring-shaped weight 7 which has a cam face 9 formed thereon is turnably held via a ball 9 against the main body 2 of a fly-wheel. A fly-weight 8 equipped with a roller and constituted of its roller portion 81 corresponding to the cam face 9, its shaft portion 82 and its needle portion 83 is mounted; the cam face 9 and the roller portion 81 function as an interlocking mechanism for the ring-shaped weight 7 and for the fly-weight equipped with a roller. The movement of the ring-shaped weight 7 in its direction of rotation and the radial movement of the fly-weight 8 may thus be related to each other, so that torque fluctuation caused in the case of low speed rotation can be absorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a constant-order dynamic damper that absorbs rotational torque fluctuations of a prime mover such as an automobile engine.

BACKGROUND OF THE INVENTION In rotating machines, the driving force of a prime mover or the resistance of a driven machine varies synchronously, which often causes variations in rotational speed, causing vibrations and noise.

In particular, in piston-type internal combustion engines, the driving force is based on the principle of converting intermittent explosions into rotational driving force using a crank mechanism, so torque fluctuations that are synchronized with the rotation of the prime mover inevitably occur. , which causes vibration.

Dampers using flywheels or torsion springs are widely used to absorb this torque fluctuation, but these are not sufficient.

In particular, in recent years, automobiles have been widely used as a means of transportation, but almost all of them are powered by piston-type internal combustion engines, and recently there has been an increase in demand for driving comfort, reducing vibration and noise caused by the above causes. It is a big challenge to do so.

Currently, as a countermeasure to this problem, multiple cylinders are being used, but increasing the number of cylinders complicates the structure and increases costs.
In addition, it causes an increase in weight and friction loss, and also increases fuel consumption, so it is only used in luxury cars.

(Prior Art) As a device for absorbing torque fluctuations in a piston-type internal combustion engine, a constant-order dynamic damper in which a pendulum-like weight is suspended from a rotating part is conventionally known (FIG. 3).

Source: See pages A3-47 and A3-146 of "Mechanical Engineering Handbook 1987 Edition" See pages 47-61 of "Proceedings of the Japan Society of Mechanical Engineers Vol. 6 No. 24 (Part 1) August 1945" In order for the order type dynamic damper to absorb torque fluctuations, the following relationship needs to hold.

B, ulhl (ll + hl) v 2ω 2 = TV However, B, ; Amplitude of the pendulum (rad), Cap; Mass of the pendulum weight (total if there are multiple), h, ; Length of the pendulum arm,
1□: Length from the center of swing of the pendulum to the center of rotation, V; Order of angular velocity of fluctuation of excitation torque with respect to rotational angular velocity, ω
: Rotation angular velocity, Tv: Excitation torque fluctuation amplitude.

Here, v=2 in an in-line 4-cylinder 4-stroke internal combustion engine, which is most commonly used in non-luxury automobiles.

Further, in order for this dynamic damper to operate effectively, it is necessary that the fluctuation period of the excitation torque and the period of the pendulum resonate, and the condition for this is 11/hl''V2.

Therefore, in the case of the above 4 cylinder 4 cycle, l,/h, =
Must be 4.

Further, L+h+ is the length from the center of rotation to the center of gravity of the weight, and this is expressed as r. Further, B and h are the amplitudes of the lateral movement amount (length) of the weight, which is expressed as X. Substituting these relationships into the torque fluctuation absorption equation above, in the case of 4 cylinders and 4 cycles, IJ + x rω' = Tv/v'
=Tv/4. That is, the value on the left side determines the torque fluctuation absorption ability of the dynamic damper.

(Problem to be Solved by the Invention) However, in such a constant order type dynamic damper, circular holes are provided in the rotating body and the weight, and the weight is moved through a roller that is commonly inscribed in these holes. hang up,
Since the weight swings relative to the rotating body by the roller rolling while contacting the inner surface of the hole, the locus of the relative movement of the weight relative to the rotating body forms an arc. However, when the locus is an arc and the amplitude becomes large, the fluctuations in the driving torque and the movement of the pendulum become out of synchronization.

In other words, the above theory holds true only when the swing angle of the pendulum is small, and according to the above-mentioned Proceedings of the Japan Society of Mechanical Engineers, B
, is set to be 10 to 15 degrees or less.

Therefore, x=B+h+≦15X n ,'Iaox r
15 = 0.052r. On the other hand, IJ,, r
There is a natural limit due to the size of the device. ω has a large value during high-speed rotation, but has a small value during low-speed rotation. However, when driving a car, engine torque fluctuations usually cause the car body to vibrate and cause discomfort when the engine speed is low.

As a result of the above, if a pendulum-type constant-order dynamic damper is designed to effectively absorb torque fluctuations transmitted to the vehicle body in a car equipped with a normal 4-cylinder 4-stroke engine, the damper would be extremely large and impractical.

In order to improve this, it has been shown that it is better to slightly modify the value of l,/h from v2, but even in that case, it was not effective over a wide range of conditions.

In other words, the conventional constant-order dynamic damper is used exclusively to reduce excessive stress generated in the engine crankshaft due to torque fluctuations during high-speed rotation, and to prevent accidents such as crankshaft breakage. However, it was not possible to prevent torque fluctuations during low-speed rotation from being transmitted to the vehicle body and causing discomfort to the occupants.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, that is, to provide a constant-order dynamic damper that effectively absorbs torque fluctuations during low-speed rotation even though it is a small damper.

(Means for Solving the Problems) In order to achieve the above object, in the constant order dynamic damper of the present invention, in order to absorb large torque fluctuations even during low speed rotation without increasing the size of the damper,
Focusing on the point that it is important to be able to obtain a large lateral movement amplitude of the weight, we have replaced the conventional pendulum type with a ring-shaped weight that moves only in the lateral direction, that is, rotational movement.
It is divided into flyweights that move only in the vertical direction, that is, in the radial direction, and the movements of both are made to have a predetermined interlocking relationship.

Specifically, a ring-shaped weight and a flyweight are attached to a rotating body that is driven while receiving fluctuating torque, and the ring-shaped weight has at least a limited rotational axis on the same rotational axis relative to the rotating body. The flyweight is mounted so as to be freely rotatable within a predetermined range, and the flyweight is limited in the radial direction by a guide with respect to the rotating body, and is freely slidable in the radial direction at least within a limited predetermined range. Between the ring-shaped weight and the flyweight,
An interlocking mechanism that associates the rotational movement of the ring-shaped weight with the radial movement of the flyweight so that the centrifugal force applied to the flyweight acts as a restoring force according to the amount of lateral movement of the ring-shaped weight. This means is characterized by the provision of.

The interlocking mechanism is composed of a cam surface formed on a ring-shaped weight and a roller section provided on the flyweight, and when the flyweight moves radially outward due to the action of centrifugal force, the roller section and the cam A mechanism is used that allows contact with the surface.

(Function) When inputting a torque fluctuation of the driving torque, the radius of curvature of the roller rolling portion where the transfer roller contacts the inner surface and transfers becomes smaller as the distance from the neutral point increases, and the rate of change of the radius of curvature decreases as the distance from the neutral point increases. Because it includes a large part,
A large amount of lateral movement of the weight can be achieved, and the restoring force applied to the weight is generated in proportion to the displacement of the weight from the neutral position.

Therefore, the torque applied to the rotating body by the swing of the weight acts in synchronization with the fluctuation of the drive torque without delay, and even though it is a small damper that only changes the shape of the rolling part of the roller, it can rotate at low speeds. It can effectively absorb torque fluctuations during

(Example) Embodiments of the present invention will be described below based on the drawings.

Note that this embodiment is an example in which a constant order type dynamic damper is attached to the flywheel of an automobile engine.

First, the configuration will be explained.

FIG. 2 is a sectional view of the flywheel portion to which the constant order dynamic damper of the embodiment is applied, in which 1 is the crankshaft output end, 2 is the flywheel body (rotating body), and 3
is the transmission input shaft, 4 is the clutch disc,
5 is a pressure plate, 6 is a diaphragm spring, 7 is a ring-shaped weight, 8 is a flyweight with a roller (flyweight), 9 is a cam surface (interlocking mechanism) formed on the ring-shaped weight 7, 10.11 is a This is a guide groove for a flyweight with rollers 8 formed in the flywheel body 2.

As shown in FIG. 2, the flywheel main body 2 is divided into a clutch connecting part 21 and a starting ring gear supporting part 22, and a key 2 is used for angular positioning of both parts 21 and 22.
3 are provided, and both 21 and 22 are integrally connected by bolts not shown.

The ring-shaped weight 7 has a cam surface 9 as shown in FIG.
It is rotatably supported to the flywheel main body 2 via a pawl 12 at an inner surface position excluding the inner surface. Note that 13 is a piece for preventing the pole from falling off.

As shown in FIGS. 1 and 2, the roller-equipped flyweight 8 is composed of a roller portion 81, a shaft portion 82, and a needle portion 83, and has cam surfaces 9 formed at six equally spaced locations on the outer circumference. The same thing is installed in 6 places correspondingly.

The guide groove 10.11 has a roller flyweight 8.
The shaft portion 82 is formed to be slidably fitted in the radial direction.

Next, a method for determining the shape of the cam surface 9 will be described.

The solid line in FIG. 1 shows a state in which the ring-shaped weight 7 is located at a neutral point and is rotating at a constant speed with no fluctuation in drive torque.

It should be noted that if there is a fluctuation in the driving torque, the ring-shaped weight 7 will swing left and right from this position, and the torque fluctuation will be absorbed by its restoring force.

Also, what is indicated by the two-dot chain line in Fig. 1 is the ring-shaped weight 7.
indicates the maximum runout position when the amplitude of is maximum.

At the neutral point, the centrifugal force applied to the roller flyweight 8 is in the radial direction, so the ring-shaped weight 7
never sway.

However, at a position deviated from the neutral point, the normal direction of the contact point between the ring-shaped weight 7 and the roller-attached flyweight 8 has an angle with the radial direction, so that the displacement of the ring-shaped weight 7 is restored, and A torque is generated in the flywheel body 2 that resists fluctuations in the driving torque.

Therefore, in order to ensure that the torque applied to the flywheel body 2 by the swinging of the ring-shaped weight 7 always acts in synchronization with the fluctuation of the drive torque in the above-mentioned situation, the flyweight with rollers 8 It is sufficient that the centrifugal force acting on the ring-shaped weight 7 acts as a restoring force proportional to the amount of lateral movement of the ring-shaped weight 7.

In order to satisfy the condition that the restoring force is proportional to the amount of movement, approximately the slope of the cam surface 9 must increase in proportion to the amount of movement, that is, the flyweight 8 with rollers relative to the cam surface 9 must be It is sufficient if the trajectory of the relative motion is a parabola.

In actuality, the inertia force needle is corrected as it moves along the cam surface 9, and the length and width are corrected so that they are in the radial direction and the circumferential direction. The shape of the cam surface 9 may be determined so that a desired locus can be obtained by rolling on the surface 9.

The shape of the cam surface 9 obtained in this manner is such that the gradient of the locus of the relative motion of the roller-equipped flyweight 8 with respect to the cam surface 9 increases as the distance from the neutral point increases, and the rate of change also increases as the distance from the neutral point increases. Become something.

Next, the effect will be explained.

(a) When the drive torque is constant: When the drive torque transmitted from the engine to the flywheel body 2 is constant without fluctuation, the flywheel body 2 rotates at a constant angular velocity without fluctuation in rotation.

At this time, the roller-equipped flyweight 8 is moved outward by centrifugal force and is at the deepest position of the cam surface 9, that is, the neutral position shown by the solid line in FIG. In this state, the ring-shaped weight 7 also rotates at the same constant angular velocity as the flywheel body 2.

Therefore, the pressing force between the roller portion 81 of the roller flyweight 8 and the cam surface 9 is directed in the radial direction, and no driving torque is generated.

(b) When the drive torque fluctuates When the drive torque transmitted from the engine to the flywheel body 2 fluctuates, the angular velocity of the flywheel body 2 also fluctuates.

At this time, the angular velocity of the flywheel body 2 no longer matches the angular velocity of the ring-shaped weight 2, a relative rotation difference occurs between the two 2°7, and the ring-shaped weight γ
performs a rocking motion relative to the This cycle corresponds to the cycle of torque fluctuations acting on the flywheel body 2.

On the other hand, since the flyweight 8 with rollers is always trying to move outward due to centrifugal force, the roller part 81 and the cam surface 9
performs a reciprocating motion in the radial direction corresponding to the rocking motion of the ring-shaped weight 7 while being in constant contact with each other.

At this time, since the contact direction between the roller part 81 and the cam surface 9 does not coincide with the radial direction and has an angle, the ring-shaped weight receives a restoring force according to the deviation from the neutral point due to this contact pressure. It turns out. At the same time, the reaction force generates contact pressure between the shaft portion 82 of the flyweight with rollers 8 and the side surface of the guide groove 10.11 provided in the flywheel body 2, which causes a variable drive torque of the flywheel body 2. This will generate a torque that cancels out the

This rocking motion of the ring-shaped weight 7 has a natural frequency determined by the inertia rate of the ring-shaped weight 7, the shape of the cam surface 9, the weight of the flyweight 8, the rotational speed of the flywheel body 2, and other conditions. have

Therefore, if the cam surface 9 is determined so that this natural frequency matches the fluctuation frequency of the driving torque, the swing amplitude of the ring-shaped weight 7 will be maximized, and the reaction force will cancel out the fluctuation of the driving torque, causing the fly to fly. Fluctuations in the rotational angular velocity of the wheel body 2 are almost eliminated.

That is, the vehicle driven by the flywheel main body 2 can suppress fluctuations in the driving torque, and can realize a smooth driving state without vibration.

In addition, when the fluctuation frequency of the driving torque changes at a constant rate with the rotational speed as in a piston type engine, the natural frequency due to the interlocking mechanism of the roller part 81 and the cam surface 9 is also proportional to the rotational speed. Because the centrifugal force applied to the flyweight 8 with rollers is proportional to the rotation speed), the so-called
Since the damper is a constant-order type dynamic damper, the above-mentioned drive torque fluctuations can be effectively absorbed in all rotational speed ranges.

As explained above, in the constant order type dynamic damper of the embodiment, the ring-shaped weight 7 moves only in the horizontal direction, that is, rotates, and the ring-shaped weight 7 moves only in the vertical direction, that is,
Flyweight with rollers that only moves in the radial direction 8
The movements of both 7 and 8 are set in a predetermined interlocking relationship so that the centrifugal force applied to the flyweight 8 with rollers acts as a restoring force proportional to the amount of lateral movement of the ring-shaped weight 7. Although it is a small damper, it is possible to effectively absorb torque fluctuations during low speed rotation.

In addition, since the interlocking mechanism that provides the interlocking relationship is a cam mechanism that includes the roller portion 81 of the flyweight 8 and the cam surface 9, it is possible to reliably transmit force with a simple structure, and the roller portion 81 is connected to the needle portion 83. Since it is rotatably supported through the cam surface 9, smooth contact movement with respect to the cam surface 9 can be ensured.

Although the embodiment has been described above based on the drawings, the specific configuration is not limited to this embodiment, and even if there is a design change within the scope of the gist of the present invention, it is included in the present invention. .

For example, in the embodiment, a cam mechanism is shown as the interlocking mechanism, but the rotation direction of the ring-shaped weight is The mechanism is not limited to a cam mechanism as long as it relates the movement of the flyweight to the radial movement of the flyweight.

(Effects of the Invention) As explained above, in the constant order type dynamic damper of the present invention, a ring that rotates within a predetermined range with respect to the rotating body is attached to the rotating body that is driven while receiving fluctuating torque. A ring-shaped weight and a flyweight that slides within a predetermined range in the radial direction are attached. An interlocking mechanism is provided that links the rotational movement of the ring-shaped weight and the radial movement of the flyweight so that it acts as a restoring force, making it a combat damper that can be applied to internal combustion engines with about 4 cylinders. However, it has the effect of effectively absorbing torque fluctuations during low-speed rotation that are transmitted to the vehicle body and cause discomfort to the occupants.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view taken along the line A-A in FIG. 2, which shows a constant-order dynamic damper according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line B-B in FIG. FIG. 3 is a diagram showing a conventional constant-order type dynamic damper. 1... Crankshaft output end 2... Flywheel body (rotating body) 3... Transmission input shaft 4... Clutch disc 5... Pressure plate 6... Diaphragm spring 7... Ring shape Weight 8... Flyweight with roller (flyweight) 81... Roller part (interlocking mechanism) 9... Cam surface (interlocking mechanism) 10.11... Guide groove

Claims (1)

[Scope of Claims] 1) A ring-shaped weight and a flyweight are attached to a rotating body that is driven while receiving a fluctuating torque, and the ring-shaped weight is attached to at least one axis of rotation relative to the rotating body. The flyweight is mounted so as to be freely rotatable within a limited predetermined range, and the flyweight is limited in a radial direction with respect to the rotating body by a guide, and is free in the radial direction at least within a limited predetermined range. A ring-shaped weight is installed between the ring-shaped weight and the flyweight so that the centrifugal force applied to the flyweight acts as a restoring force according to the amount of lateral movement of the ring-shaped weight. A constant-order dynamic damper, characterized in that it is provided with an interlocking mechanism that correlates the rotational movement of a weight with the radial movement of the flyweight. 2) The interlocking mechanism is composed of a cam surface formed on a ring-shaped weight and a roller section provided on the flyweight, and when the flyweight moves radially outward due to the action of centrifugal force, the roller section and the cam The constant order type dynamic damper according to claim 1, which is an interlocking mechanism in which the damper contacts a surface.