JP4311716B2 - Self-following resonance device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a self-following resonance device that is a kind of dynamic damper and that can automatically change a resonance frequency in accordance with input vibration.
[0002]
[Prior art]
A dynamic damper that controls vibration by combining a mass and a spring is known. In this dynamic damper, since the resonance frequency is fixed by the mass and the spring constant, it is known that the mass is controlled by an external force in order to change the resonance frequency according to the input vibration (Patent Document). 1).
In addition, there is a vibration system in which a lever is provided and a mass is provided at the tip of the lever to change the position (see Patent Document 2).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 6-1097 [Patent Document 2]
Japanese Examined Patent Publication No. 8-16497
[Problems to be solved by the invention]
By the way, the above-described conventional example has an advantage that the resonance frequency can be varied, but on the other hand, the mass is controlled, so that it becomes a large and complicated system, and is expensive. Therefore, it is desired to realize this at a low cost with a relatively simple structure, and the present invention aims to realize this requirement.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a self-following resonance device according to the present application is characterized in that one end is supported by a cylindrical bush and the other end is rotatable, a mass supported by the lever, It consists of a pendulum type dynamic damper that has a damping spring that elastically biases in a direction to prevent rotation, and that rotates the lever with the mass around the support point by the cylindrical bush according to the input vibration ,
The mass movably supported to the longitudinal direction on the lever, working the centrifugal force acting to move the this mass in a direction away from the support point by the rotation of the lever, to the opposite direction The mass is moved according to the input vibration by the balance with the return force that moves the mass in the direction of the support point .
The damping spring is an anti-vibration rubber forming a torsion spring constituting the cylindrical bush,
The support point of the lever is located at the center of the torsion spring .
[0006]
A second aspect of the present invention is characterized in that, in the first aspect, the return force is a force that drops a mass generated by tilting the lever.
[0007]
A third aspect is characterized in that, in the first aspect, the return force is a force generated by a spring or a magnetic force.
[0008]
A fourth aspect of the present invention is characterized in that, in the first aspect, a moving speed suppressing means for suppressing a moving speed of the mass on the lever is provided.
[0009]
According to a fifth aspect of the present invention , in the first aspect, the cylindrical bush includes an inner cylinder, a bracket disposed outside the inner cylinder, and the antivibration rubber provided between the inner cylinder and the bracket. The center is the torsion spring center, and one end of the lever is press-fitted into the inner cylinder .
[0011]
【The invention's effect】
According to claim 1, when the lever is rotated up and down by input vibration, the mass is vibrated together with the lever, thereby receiving a centrifugal force in a direction away from the support point, and simultaneously receiving a return force in the opposite direction. The mass moves freely on the lever to the balance point between centrifugal force and return force.
[0012]
This centrifugal force changes according to the vibration frequency, that is, the angular velocity of vibration, and the return force is substantially constant. Therefore, the balance point changes according to the input frequency. For this reason, the moment force of the mass changes according to the distance from the support point to the balance point.
Therefore, if the equivalent mass that this moment force is considered to act on the point of action of the damping spring is calculated, this vibration system functions as a dynamic damper composed of the equivalent mass and the spring of the damping spring. The input vibration is damped by resonating at a predetermined resonance point determined by the damping spring.
[0013]
In addition, since the equivalent mass changes according to the input frequency, the resonance point of the dynamic damper voluntarily changes according to the input vibration. Therefore, even when the input vibration changes, vibration can be controlled by automatically changing the resonance point. Moreover, it can be realized with an extremely simple structure without requiring a special control device.
Further, by setting the center of the torsion spring of the vibration isolating rubber constituting the cylindrical bush as a support point of the lever, vibration can be controlled by rotating the lever in a pendulum manner by supporting the lever on the cylindrical bush. Therefore, the pendulum dynamic damper can be configured easily.
In addition, since the damping spring is a torsion spring, the rotation due to the vibration of the lever can be converted into the torsion of the torsion spring to generate a return force in the reverse direction. Moreover, since it can be formed using a rubber spring, it can be made relatively compact.
[0014]
According to claim 2, by tilting the lever, a drop force toward the support point can be generated in the mass, and this can be used as a return force. Therefore, the return force can be generated only by tilting the lever, and the magnitude of the return force can be freely set by changing the tilt of the lever.
[0015]
According to the third aspect, the return force can be forcibly generated by elastically urging the mass toward the support point using a spring or magnetic force. Therefore, a return force can be generated even if the lever is horizontally disposed, and a stable return force can be forcibly obtained regardless of the inclination of the lever.
[0016]
According to the fourth aspect of the present invention, since the mass moving speed suppressing means is provided, the mass can be prevented from abruptly moving and moved relatively slowly, and the balance can be quickly moved to the balance point accurately. It can be positioned on a point. As such a moving speed suppressing means, for example, a viscous resistance provided between the mass and the lever or a mass flow resistance provided by moving the mass provided with the throttle passage in the liquid in the cylinder-shaped lever is used. There is.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments will be described below with reference to the drawings. 1 to 4 all SANYO for explaining the principle of self followers type pendular dynamic damper in the present invention except for the support structure of the lever by the cylindrical bushing, FIG. 1 is a schematic of the entire apparatus, and FIG. 2 is acting FIG. 3 is an explanatory diagram, FIG. 3 is a principle diagram using an equivalent mass, and FIG. 4 is a diagram showing an amplitude change during resonance.
[0020]
In FIG. 1, the dynamic damper 1 includes a lever 2, a mass 3 supported on the lever 2 so as to be axially movable, a support point 5 that rotatably supports one end side of the lever 2 to a support portion 4, and And a damping spring 6 attached to the free end of the lever 2. Reference numeral 7 denotes a free end, and 8 denotes a support base portion of the dynamic damper 1.
[0021]
The lever 2 is made of an appropriate material such as a round bar, for example, a surface having low friction, and is attached to the support portion 4 so as to form an inclination angle θ with respect to the horizontal plane, and the free end side is It is higher than the support point 5. In this example, the state in which the lever 2 forms the inclination angle θ is the basic state.
[0022]
The mass 3 is made of metal or the like and has an appropriate mass. For example, the through hole 9 is provided, and the mass 3 is movable on the lever 2 in the longitudinal direction by passing the lever 2 therethrough. However, the support structure of the mass 3 by the lever 2 is not limited to the above, and can be arbitrarily set such as a monorail guide. The magnitude of the mass can be set arbitrarily according to the desired dynamic damper characteristics.
[0023]
The damping spring 6 suppresses vertical movement at the free end of the lever 2, and its spring constant can be arbitrarily set according to the desired dynamic damper characteristics. The material is arbitrary, such as metal or rubber, and the shape can be a coil spring or other various shapes.
[0024]
The dynamic damper 1 inputs a vibration to the free end side of the lever 2 and rotates the lever 2 up and down, thereby generating a dynamic damper effect due to the interaction between the rotating mass 3 and the damping spring 6. Vibration is controlled.
[0025]
The operation principle of the dynamic damper 1 will be described with reference to FIGS. The symbols and symbols used in the following are as follows. The length of the lever 2 is L, the mass of the mass 3 is m, the distance on the lever 2 from the support point 5 to the mass 3 is r, the force of gravity acting on the mass 3 is G, the acceleration of gravity is g, and the centrifugal force is F , V is the velocity when the mass 3 vibrates, ω is the angular velocity when the lever 2 is rotated, x _{0 is} the amplitude, and K is the spring constant of the damping spring 6.
[0026]
Here, the mass 3 on the lever 2 rotated by the input vibration has a free end 7 on the lever 2 by a force G that tries to slide down on the lever 2 to the support point 5 side by gravity and a centrifugal force by the vibration. The centrifugal force F to be moved to the side acts in the opposite direction. The force G due to gravity is a return force. The values of centrifugal force and G are as follows.
[0027]
Centrifugal force F = mv ² / r = m (x ₀ ω) ² / r
Gravity force G = m ・ g ・ sinθ
When the mass 3 stops moving on the lever 2 at the balance point between the forces F and G in the reverse direction, F = G.
[0028]
Here, the equivalent mass M is defined by the simplified model shown in FIG. That is, the moment force acts on the damping spring 6 at the point of the distance L from the support point 5, that is, the free end 7 by the mass 3 located at a point on the distance r from the support point 5 on the lever 2, An imaginary mass on the damping spring that produces a force by gravity equal to the moment force is defined as an equivalent mass M.
[0029]
In this dynamic damper system, the resonance frequency is
ω _n = (K / M) ^1/2 = {(K / m) (L / r)} ^1/2
From this, M = m · (r / L)
It becomes.
[0030]
Next, the behavior when the lever 2 is rotated by vibration input will be described. When the lever 2 is rotated at the vibration frequency by the vibration input, the centrifugal force F corresponding to the vibration acts on the mass 3. In general, the centrifugal force increases as the frequency increases.
[0031]
Therefore, when the centrifugal force F increases and exceeds the force G due to gravity, the mass 3 moves on the lever 2 to the balance point. If the position on the lever 2 at this time is r, the resonance frequency ωn at that point is determined by the equivalent mass M at that time by the above equation, and the equivalent mass M is also determined by m · (r / L). Accordingly, the mass 3 moves according to the frequency of the input vibration, and the resonance frequency ωn of the dynamic damper 1 automatically changes.
[0032]
Further, since the equivalent mass M has a relationship of m · (r / L), the larger r is, that is, the larger the mass is moved toward the free end 7 side approaching L. On the other hand, the resonance frequency ωn becomes lower as the equivalent mass M increases from the above equation. Therefore, when the frequency of the input vibration increases, the centrifugal force F increases and the mass 3 moves on the lever 2 to the free end 7 side, but conversely, the resonance frequency ωn decreases due to the increase of the equivalent mass M.
[0033]
Further, as shown in FIG. 4, the general vibration amplitude x ₀ increases as the frequency increases toward the resonance point, and decreases as the frequency increases after passing the resonance point.
[0034]
This means that the movement of the mass 3 on the lever 2 moves to the free end 7 side until the resonance frequency ωn is reached, but if the movement further exceeds the resonance frequency ωn, the equivalent mass M becomes too large and the resonance frequency ωn becomes too large. Since it becomes lower and the amplitude becomes smaller, the centrifugal force F becomes smaller, and as a result, it returns to the resonance point. For this reason, the mass 3 automatically moves in a balanced manner to a position that becomes a resonance point.
[0035]
That is, it means that the dynamic damper 1 automatically adjusts the resonance frequency following the frequency of the input vibration. As a result, a self-following resonance device with a simple structure, a small size, and a light weight can be obtained. Moreover, since gravity is used as the return force, the structure can be further simplified.
[0036]
FIG. 5 shows an example in which a damper 10 is added to the damping spring 6. In this example, a damper 10 in parallel with the damping spring 6 is provided at the free end 7. If it does in this way, since damping by damper 10 will be performed, a vibration proof effect can be enlarged more.
[0037]
FIG. 6 shows an example in which sliding resistance means 11 made of viscous oil or the like is provided on the lever 2 or on the sliding portion of the mass 3, and thereby the mass 3 is moved slowly to change the resonance frequency suddenly. Can be prevented. That is, the sliding resistance means 11 serves as mass moving speed suppression means.
[0038]
FIG. 7 and subsequent figures are examples in which the basic state of the lever 2 is horizontal and the return force is other than the force due to gravity. In FIG. 7 , the lever 2 cantilevered at the support point 5 is leveled, and the mass 3 is supported on the lever 2 so as to be movable in the axial direction. The return spring 12 pulls the lever 2 toward the support point 5. As a result, the return spring 12 applies a return force R to the mass 3. Except for this point, the resonance frequency can be automatically adjusted as in the previous examples . The free end 7 side may be either the damping spring 6 alone or in combination with the damper 10.
[0039]
In FIG. 8, magnets 13 and 14 are provided between the mass 3 and the free end 7 side of the lever 2 so that the facing sides have the same polarity. The magnet can be a permanent magnet or an electromagnet. Thereby, when the mass 3 approaches the free end 7 side, the magnet 13 and the magnet 14 repel each other with the same polarity, and push the mass 3 back to the support point 5 side with a magnetic force. In this case, the magnetic force becomes the return force R.
[0040]
In addition, a pair of magnets made of a combination of different polarities can be arranged to face each other between the support point 5 side and the mass 3, and the magnetic force can be used as the attractive force. In any of these cases, when the return force R is a magnetic force, the return force R is proportional to the square of the displacement amount of the mass 3 on the lever 2, so that the movement to the resonance point can be accelerated. .
[0041]
In FIG. 9 , the support point 5 is provided at the intermediate portion of the lever 2, the damping spring 6 is provided at one end of the lever 2, the other end is a free end 7, and the mass 3 is provided between the support point 5 and the free end 7. It is supported so as to be movable in the axial direction, and is pulled by the return spring 12 to the support point 5 side.
[0042]
In this way, the size of the equivalent mass M can be increased by the lever ratio with respect to the movement amount of the mass 3. In addition, it is free to use the damper 10 in combination with the damping spring 6. It is also possible to apply the supporting point structure to other examples including FIG. 1, 5, 6 or the like.
[0043]
In FIG. 10 , the mass 3 is accommodated in a cylindrical body 15 filled with an incompressible liquid and is slidable as a piston in the axial direction, and the liquid moves between both sides of the mass 3 by an orifice 16 provided in the mass 3. Is possible.
[0044]
One end of the cylindrical body 15 is rotatably supported by a support point 5, and a damping spring 6 and a damper 10 are provided on the free end 7 side of the other end. A return spring 12 is also provided as a return force between the end portion on the support point 5 side in the cylinder 15 and the mass 3. The use of the damper 10 is optional.
[0045]
When vibration is input to the free end 7 side and the cylinder 15 is rotated, the mass 3 moves in the cylinder 15 according to the frequency of the input vibration. At this time, the mass 3 is attenuated by the orifice 16. Therefore, a resistance against the movement of the mass 3 is provided, and this resistance is provided in the orifice 16 and can be arbitrarily adjusted. That is, the flow resistance of the liquid generated at the orifice 16 serves as a mass moving speed suppressing means. The structure in which the mass 3 is accommodated in the cylindrical body 15 and the resistance is given by the orifice 16 can be applied to the inclined support structure in the above-described example .
[0046]
11 and 12 are real施例, in this example, it is configured as a pendulum dynamic damper having a cylindrical bush 20 and the lever 2 and mass 3. That is, one end of the lever-2 is fixed to the inner cylinder 21 of the cylindrical bush 20 by press fitting or the like, and by rotating together with the inner cylinder 21, the lever 2 rotates in a pendulum manner. 3 moves on the lever 2 to constitute the self-following dynamic damper described above.
[0047]
The cylindrical bush 20 is provided with a bracket 22 surrounding the inner cylinder 21, and a vibration-proof rubber 23 is provided between the bracket 22 and the inner cylinder 21, and these are integrated by baking or the like. The cylindrical bush 20 controls the mounting counterpart as a dynamic damper by mounting the mounting portion 24 to a vibration suppression target as a vibration source by an appropriate means such as a bolt.
[0048]
The anti-vibration rubber 23 functions as a torsion spring with respect to the rotation of the lever 2. The torsion spring center 25 of the anti-vibration rubber 23 that is a torsion spring coincides with the center of the inner cylinder 21, that is, the rotation center of the lever 2. Therefore, this vibration system functions as a vibration damper of the dynamic damper. The operation of the lever 2 and the mass 3 as a self-following dynamic damper is the same as described above.
[0049]
In this way, if the self-following dynamic damper is combined with the cylindrical bush 20 to form a pendulum, the mounting angle of the lever 2 can be adjusted to easily adjust the mounting angle in accordance with the input direction of the vibration to be isolated. It can be adjusted and the dynamic damper can be installed at the optimum angle.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an entire apparatus according to the principle explanation of the present invention . FIG. 2 is an action illustration according to the principle explanation. FIG. 3 is a principle diagram using an equivalent mass according to the principle explanation . FIG. 5 is a schematic diagram according to an example in which a damper is added to a damping spring . FIG. 6 is a schematic diagram according to an example in which mass sliding resistance means is provided . Schematic diagram related to an example using a return spring that pulls a mass in the axial direction as a return force . FIG. 8 is a schematic diagram related to an example using a magnetic force as a return force . FIG. 9 is an example in which a support point is provided in the middle of the lever . schematic view according to FIG. 10 taken along line 12-12 of schematic Figure 12] Figure 11 incompressible liquid masses according to schematic 11 real施例according to the example provided in encapsulated tubular body Sectional view along the line 【Explanation of symbols】
1: dynamic damper, 2: lever, 3: mass, 5: support point, 6: damping spring, 7: free end, 10: damper, 11: return spring, 12: magnet, 13: magnet, 14: uncompressed Liquid, 15: cylinder, 16: orifice, 20: cylindrical bush

Claims (5)

A lever with one end supported by a cylindrical bush and the other end pivotable, a mass supported by the lever, and a damping spring that elastically biases the lever in a direction that prevents rotation of the lever Accordingly, the lever comprises a pendulum type dynamic damper that rotates with the mass around a support point by the cylindrical bush.
The mass movably supported to the longitudinal direction on the lever, working the centrifugal force acting to move the this mass in a direction away from the support point by the rotation of the lever, to the opposite direction The mass is moved according to the input vibration by the balance with the return force that moves the mass in the direction of the support point .
The damping spring is an anti-vibration rubber forming a torsion spring constituting the cylindrical bush,
A self-following resonance apparatus characterized in that a support point of the lever is positioned at the center of the torsion spring . 2. The self-following resonance device according to claim 1, wherein the return force is a force that drops a mass generated by tilting the lever. The self-following resonance apparatus according to claim 1, wherein the return force is a force generated by a spring or a magnetic force. The self-following resonance apparatus according to claim 1, further comprising a moving speed suppressing unit for suppressing a moving speed of the mass on the lever. The cylindrical bush includes an inner cylinder, a bracket disposed outside the inner cylinder, and the anti-vibration rubber provided between the inner cylinder and the bracket, and the center of the inner cylinder is the center of the torsion spring. The self-following resonance apparatus according to claim 1 , wherein one end of the lever is press-fitted into a cylinder .

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