JP2009052577A - Variable rigidity dynamic vibration-damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a conventional variable rigidity dynamic vibration damper makes its big structure difficult to accomplish an accurate tuning in a narrow frequency-range, mounting of the damper difficult, and a major design-change necessary when the tuning range is to be changed even though the adjustment of the natural frequency is most important in damping the vibration. <P>SOLUTION: This device includes a pair of long rigid members of the same rigidity, a vibration damper main-body, a plumb bob, and a rotating mechanism. In each of the long rigid members, the axis of rotation is positioned on the same straight line in the direction of the linear vibration of the vibrating body, or on one side of parallel lines on the same orthogonal surfaces, and a long shaft and a short shaft are provided on the cross section. The vibration damper main-body is installed to the vibrating body, and provided rotatably with each outside of the pair of long rigid bodies. The respective insides of the pair of long rigid members are connected by means of bearings at respective central parts, and the plumb bob is suspended by gear meshing so as to be reversely rotatable in a symmetric state with respect to a point. By the rotating mechanism, a coefficient of composite rigidity is varied, while the composite vibration direction of the pair of long rigid bodies is held in the direction of linear vibration of the vibrating body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable stiffness dynamic vibration absorber for translational vibration.

  In the industry, regular patterns are gradually formed on the roll and the system in contact with the roll as the contact rotation system is operated, and it also induces severe vibration or is transferred to the product. There are many phenomena that result in defective products. For example, railroad vehicles and rails, drive rolls and bobbin holders via yarn balls of textile machinery winders, a pair of paper machine rubber rolls, automobile tires and roads, steelmaking machines, machine tools, etc. have specific patterns. It is formed. These phenomena are called pattern formation phenomena, and the mechanism of their occurrence has been elucidated and countermeasures have been studied.

In particular, in steelmaking machines, chatter marks for tension levelers and chattering during hot / cold rolling have become serious problems in product management as the accuracy of products increases. On the other hand, the roll polygonalization phenomenon of smoother rolls and gate roll size presses in the press part of the paper machine is also the main cause that hinders the improvement of the line speed.
Most of these phenomena are pattern formation phenomena that occur in a contact roll system in which the roll rotates in contact with the roll.

From the viewpoint of global research, this kind of contact rotation system pattern formation phenomenon is mainly researched on chattering of machine tools and corrugation of railway rails in Japan. The research on the pattern formation phenomenon of the contact roll system in which the roll rotates is in the developing stage. In particular, the chattering phenomenon that occurs in steelmaking machines such as hot rolling and cold rolling, the polygonal deformation phenomenon of rolls in paper machines, and the abnormal vibration in the winding process of thin strips of paper, etc., still have a clear mechanism. It has not been elucidated. Therefore, as a countermeasure in the field against the pattern formation phenomenon that occurs in such a contact roll system, only the line speed is slowed down or the rolls are replaced early, and the fundamental problem is not solved.
When this phenomenon occurs, the industry has to deal with fatal damage or set an upper limit of the line speed. Therefore, the industry is urgently required to develop a countermeasure.
However, such preventive measures have not yet been studied.
In previous studies, as measures to prevent the pattern formation phenomenon, we studied methods for reducing the instability by optimizing the roll diameter ratio and measures for delaying pattern formation that fluctuates the roll rotation speed, and proposed design guidelines. I have done it. The diameter ratio optimization method is effective when the paired rolls are deformed equally and symmetrically, but is ineffective when one of the rolls is deformed. Moreover, since there are many cases where it is necessary to operate at a constant rotation speed, such as an iron-making machine or a papermaking machine, the types of machines that can take countermeasures are limited.
In addition, we theoretically analyzed how the pattern formation phenomenon is affected by attaching a passive dynamic vibration absorber. As a result, unlike the vibration damping effect of a dynamic vibration absorber for general self-excited vibration, there is a problem that a drastic vibration damping cannot be expected and a vibration mode to be damped appears newly.
Further, in a winder system of a textile machine, a winder of a thin ribbon such as paper, etc., the natural frequency of the system changes every moment, so vibration suppression is impossible with a passive dynamic vibration absorber.
In order to solve the above problems, the present inventor introduced a single-support type variable stiffness type dynamic vibration absorber according to Patent Document 1 and also introduced a single-support type variable stiffness type dynamic vibration absorber introduced in Patent Document 1. Some disadvantages of the vessel, that is, the vibration absorber is supported in one piece via a pair of identical rigid long rigid bodies and the weight vibrates in a circular arc. Patent Document 2 introduced a variable-rigidity dynamic vibration absorber of a double-support system that has been improved to be difficult to change in a plane-symmetrical state or in an exact parallel relationship.
The variable stiffness type dynamic vibration absorber of the one-side support type is a pair of identical rigid long rigid bodies having respective axial centers located on the same orthogonal plane with respect to the vibration direction of the vibrating body and having a major axis and a minor axis in the cross section. A vibration-absorbing body attached to a vibrating body and rotatably mounted on only one side of the pair of long rigid bodies, and a weight mounted rotatably on each other side of the pair of long rigid bodies, A mechanism for rotating the pair of long rigid bodies in opposite directions in a plane-symmetric state to change the combined stiffness coefficient while maintaining the combined vibration direction of the pair of long rigid bodies in the linear vibration direction of the vibrating body It consists of.
The variable stiffness type dynamic vibration absorber of both support systems is a pair of the same rigid long rigid body having a long axis and a short axis in the cross section, each axial center being located on the same orthogonal plane with respect to the vibration direction of the vibrating body, A vibration-absorbing body attached to a vibrating body and rotatably mounted on both sides of the pair of long rigid bodies, a weight mounted rotatably on the center of the pair of long rigid bodies, and the pair of long rigid bodies A mechanism that rotates the rigid bodies in opposite directions in a plane-symmetric state and changes the combined stiffness coefficient while maintaining the combined vibration direction of the pair of long rigid bodies in the linear vibration direction of the vibrating body. Become.

The adjustment of the natural frequency is the most important for damping the vibration with the dynamic vibration absorber. The variable stiffness type dynamic vibration absorber used before the above-mentioned invention is a mechanism that moves the mass part at the tip of the cantilevered beam back and forth, and is structurally large, making it difficult to tune a narrow frequency range with high accuracy. Met. In addition, it is difficult to mount the attenuator, and there are problems such as a large design change when changing the tuning range.
Further, in the structure introduced in Patent Document 2, since the weight is supported by the long rigid body at four locations, the vibration absorbing main body serving as a base has to be a large structure. When the vibration absorbing main body is structurally large, the vibration characteristics of the vibration system targeted for vibration control are changed by mounting the vibration absorbing main body. Therefore, it is desirable that the vibration absorbing body has a structure as small as possible. If the vibration-absorbing body is too large, there is a possibility that the damping effect cannot be obtained, which is a problem.

Therefore, the present invention provides a variable stiffness type dynamic vibration absorber that solves the above-mentioned problems, and features thereof are as follows.
(1) The rotation axis is located on the same straight line perpendicular to the linear vibration direction of the vibrating body or on one side of the parallel lines on the same orthogonal plane, and the major axis and the minor axis are arranged in the cross section. A pair of long rigid bodies having the same rigidity, a vibration-absorbing body attached to a vibrating body and rotatably mounted on each outer portion of the pair of long rigid bodies, and inner portions of the pair of long rigid bodies. The combined vibration direction of the weight coupled to the center portion and suspended by the gear connection so as to be able to reversely rotate in a point-symmetric state with each other and the pair of long rigid bodies is maintained in the linear vibration direction of the vibrating body. A variable stiffness type dynamic vibration damping device comprising a rotation mechanism that changes the composite stiffness coefficient.

In the present invention, the pair of long rigid bodies have their inner portions bearing at the center of the weight (vibrating mass) and geared so as to be able to reversely rotate with each other, and in addition, they are identical to each other and perpendicular to the linear vibration direction of the vibrating body. The number of long rigid bodies has been reduced to half of the conventional one by arranging them on each side of parallel lines on the same orthogonal plane. Can be realized.
Further, according to the present invention, the frequency to be tuned can be selected almost freely by the above configuration, and the structural size is hardly changed, and a very narrow frequency range can be tuned with high accuracy. Since only the stiffness coefficient is variable, fewer design parameters need to be adjusted, making it easy to mount the attenuator and change the tuning range. This is particularly effective when the installation range is limited and compactness is required. Further, the size of the vibration absorbing main body can be designed to be very small, and the influence of the vibration absorbing main body on the vibration system to be controlled can be suppressed to a very small size.
As described below, the present invention has a number of applications to iron making machines, paper making machines, and the like, and has an extremely beneficial effect industrially.
a). In a cylindrical roll, a bearing such as a slide bearing can be provided via a central axis, and the bearing can be arranged via the bearing.
b). A backup roll is attached to the roll surface, and the vertical vibration attached to the backup roll bearing is absorbed.
In these examples, the vibration damping effect can be obtained even in the vibration mode in which the amplitude of the roll bearing portion contacting the roll surface is small.
c). It is applied as a corrugation for rails and a polygonal prevention device for wheels.
As the train repeats running, the surface of the rail and the wheels are deformed into a polygon (corrugation), and noise, a decrease in the service life of the rail, and driving safety problems occur. Corrugation is prevented by attaching a vibration absorber to the axle portion through a bearing and suppressing the vertical vibration of the wheel.
d). Apply to machine tools.
In order to suppress chatter vibration of the machine tool, a vibration absorber is mounted on the tool.
e). Applied to automobile brake squeal prevention device.
The disc brake squeal of an automobile is self-excited vibration caused by the combination of a rotor and a pad or a rotor and a caliper. The latter, which is a particular problem, can be reliably suppressed by attaching a dynamic vibration absorber to the caliper. However, when a vibration absorber tuned by a bench test is attached to an actual vehicle, the effect is often not obtained due to the difference in chassis structure. Since this vibration absorber can be easily tuned, it is also effective in the brake squeal phenomenon of an actual vehicle. Possible mounting locations include calipers, rotor interiors (in which case a plurality are required), and hydraulic piston interiors. In addition, the former squeal is attached to the pad.
f). Applied to automobile suspension.
By mounting this device on the suspension upper part of the automobile, it is possible to minimize the vibration to the vehicle body due to the forced vibration of the road surface.
g). Other applications include building vibration suppression due to earthquakes, self-excited vibration (galloping) suppression of electric wires, and prevention of train squeal noise.

In the variable stiffness type dynamic vibration absorber of the present invention, the shape of the long rigid body is the same at both ends of the vibration mass, and the combined vibration direction received by the weight from the pair of rigid bodies is always the same as the vibration direction of the vibration body. It becomes a cross-sectional shape having a major axis and a minor axis such as a rectangle and an ellipse that rotate in the opposite direction by changing the point symmetry state of the rotation angle and continuously change the composite stiffness coefficient.
In addition, as the rigidity coefficient changing mechanism of the long rigid body, as an example of an appropriate rotation coupling mechanism of the long rigid body, for example, a gear-type rotating device, the same specification is applied to the rotating shaft inside the long rigid bodies within the vibration mass. Type in which these gears are directly meshed and connected to each other and reversely rotated, or in place of the gears, bevel gears are provided and these are connected via a pair of bevel gears so that they are mutually reversely rotated. Is simple.
As another example, a pair of long rigid bodies are provided by providing cylindrical gears of the same specification on the rotation shafts of the respective inner portions of the long rigid bodies and meshing the lower part of each cylindrical gear with one small-diameter intermediate cylindrical gear. The type that reversely rotates can be fried.
The combined vibration direction received by the weight (vibrating mass) from the long rigid body is always only the vertical (translation) direction of the vibrating body, and the composite stiffness coefficient changes continuously by changing the rotation angle of the pair of long rigid bodies. To do. As a mechanism for changing the stiffness coefficient of the long rigid body, an appropriate rotating device for the long rigid body is used.

Next, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a plan sectional view taken along the line AA in FIG. FIG. 2 is a side cross-sectional view from the arrow BB in FIG.
1 to 2, the vibration absorbing body 2 is attached to the vibrating body 1, and a pair of bearing stands 2-1 and 2-2 are installed on the vibration absorbing body 2. ) The outer parts of 3 and 4 are formed on the rotating shafts 3a and 4a, and the bearings B1 and B2 are rotatably mounted on the bearings. The inner parts of the leaf springs 3 and 4 are formed on the rotating shafts 3b and 4b. Is attached to the center of the weight 5 so as to be rotatable by bearings B3 and B4, and bevel gears K1 and K2 are connected to each other via a pair of bevel gears K3 and K4 so that they can rotate in reverse with each other. To do. A rigidity coefficient changing mechanism 6 for rotating the leaf spring 3 is attached to the stand 2-1 on the leaf spring 3 side.
The lower surface of the vibration absorbing body 2 is attached to the vibrating body 1 so as to coincide with the orthogonal line H1 with respect to the vibration direction V of the vibrating body 1.
The leaf springs 3 and 4 have the same rectangular cross section (a type of rectangle), and their axial cores C1 and C2 are positioned on the same orthogonal line H2 with respect to the vibration direction V of the vibrator 1, and the cross sectional length thereof. The axes L1 and L2 are made to coincide with the vibration direction V at the reference position.
The plate spring stiffness coefficient changing mechanism 6 fixes the main gear 7 to the rotation shaft 3a of the plate spring 3 set to the reference position, and engages the drive gear mechanism 8 with the rotation shaft 3a to rotate the servo motor 9 for rotation adjustment. The drive gear mechanism 8, the main gear 7, the leaf spring 3, the bevel gears K1 to K4, and the leaf spring 4 are operated at rotational angles to change the combined stiffness coefficient of the leaf springs 3 and 4.
The servo motor 9 for adjusting the rotation is provided with a controller 10 that controls the rotation operation to a leaf spring rotation angle that coincides with each other based on the vibration frequency detected from the vibration frequency detector 11 of the vibrating body 1 and the vibration absorbing body 2. .
In FIG. 2, reference numeral 5-1 denotes a guided rod fixedly protruding below the weight 5 and guided along the vibration direction V of the vibrating body 1 by a guide cylinder 2-3 provided at the center of the vibration absorbing body 2. The

Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a cross-sectional plan view taken along the line CC in FIG. FIG. 4 is a side sectional view taken along the line DD in FIG.
The difference between Example 2 and Example 1 is that cylindrical gears E1 and E2 of the same specification are provided on the rotating shafts on the inner side of the pair of leaf springs 3 and 4 (long rigid body), and these are directly meshed with each other. It is a type that is connected and reversely rotated. For this reason, the leaf springs 3 and 4 have their axial cores C1 and C2 arranged on one side of parallel lines H1 and H2 on a plane orthogonal to the vibration direction V of the vibrating body 1, respectively.
The rest of the configuration is the same as that of the first embodiment, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  As described above, each embodiment of the present invention includes a pair of the long rigid bodies: the inner portions of the leaf springs 3 and 4 that are supported by the central portion of the weight 5 and geared so as to be able to reversely rotate with each other. 1 on the same straight line H2 orthogonal to the linear vibration direction V, or on each side of the parallel lines H3 and H4 on the orthogonal plane, thereby reducing the number of leaf springs 3 and 4 to half of the conventional number. The rotation mechanism 6 can reliably change the rotation angle of the pair of leaf springs 3 and 4 in the point-symmetrical state by the rotation mechanism 6 even in a narrow frequency range. The composite stiffness coefficient is continuously changed, and the natural frequency on the vibration absorbing body 2 side is accurately tuned to the natural frequency of the vibration body 1 to suppress, reduce or delay the vibration of the vibration body 1.

  The present invention has the above-mentioned effects, can be widely applied to many vibration bodies such as transportation such as cars and trains, and mechanical vibrations, and can also be used for countermeasures against noise problems. It is most effective and has very high industrial applicability.

It is explanatory drawing which shows Example 1 of this invention apparatus, and is a plane sectional view from arrow BB of FIG. FIG. 2 is a side sectional view taken along the line AA in FIG. 1. It is explanatory drawing which shows Example 2 of this invention apparatus, and is a plane sectional view from arrow DD of FIG. FIG. 5 is a side sectional view taken along the line CC in FIG. 4.

Explanation of symbols

1 Vibrating body 2 Vibration absorbing body 3, 4 Leaf spring (long rigid body)
3a, 4a, 3b, 4b Rotating shaft 5 Weight 6 Rigidity coefficient changing mechanism 7 Main gear 8 Drive gear mechanism 9 Servo motor for rotation adjustment
10 Controller
11 Vibration frequency detector

Claims (1)

  A pair of identical axes having a rotational axis centered on the same straight line orthogonal to the linear vibration direction of the vibrating body or on each side of parallel lines on the same orthogonal plane and having a major axis and a minor axis in the cross section A rigid long rigid body, a vibration-absorbing body attached to the vibrating body and rotatably mounted on the outer portions of the pair of long rigid bodies, and bearings on the inner portions of the pair of long rigid bodies at the center. The combined stiffness coefficient of the weight that is coupled and suspended so as to be reversibly connected in a point-symmetric state and the pair of long rigid bodies is maintained in the linear vibration direction of the vibrating body, and the resultant stiffness coefficient is A variable-rigidity dynamic vibration absorber comprising a rotating mechanism that changes.

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