JP2014149027A - Spring device and vibration insulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated leaf spring capable of easily adjusting a surging frequency.SOLUTION: A laminated leaf spring comprises a plurality of leaf springs 1 connected in parallel. The leaf spring 1 has a distorted part 11 deformed by receiving a load. Between respective distorted parts 11 of adjacent leaf springs 1, a clearance 5 is formed. The leaf springs 1 comprise a plurality of kinds of leaf springs 1 whose eigen frequencies are different from each other. An attenuation member 6 injected to the clearance 5 between the respective distorted parts 11 of adjacent leaf springs 1 is included.

Description

  The present invention relates to a spring device and a vibration isolation device that suppress transmission of vibration from a vibration source to an object.

  2. Description of the Related Art Conventionally, a lap leaf spring including a plurality of leaf springs connected in parallel and stacked in a plate thickness direction is known. Each leaf spring is disposed in contact with an adjacent leaf spring so that a frictional force is generated between the leaf springs (see, for example, Patent Document 1).

JP 58-199207 A

  However, since the adjacent leaf springs are in contact with each other, in order to adjust the surging frequency of the leaf springs, the entire leaf spring must be designed. There was a problem that adjustment was difficult.

  The present invention provides a spring device and a vibration isolation device capable of easily adjusting a surging frequency.

  The spring device according to the present invention is a spring device including a plurality of spring members connected in parallel, and the spring member has a strain generating portion that is deformed by receiving a load, and each of the adjacent spring members. A clearance is formed between the strain generating portions.

  According to the spring device according to the present invention, since the clearance is formed between the respective strain generating portions of the adjacent spring members, the surging frequency of each spring member becomes the surging frequency of the spring device as it is. As a result, it is possible to easily adjust the surging frequency of the spring device by adjusting the surging frequency of each spring member.

It is a front view which shows the laminated leaf | plate spring which concerns on Embodiment 1 of this invention. It is a block diagram which shows the dynamic model of the laminated leaf | plate spring of FIG. It is a graph which shows the dynamic rigidity of the laminated leaf | plate spring of FIG. It is a front view which shows the laminated leaf | plate spring which concerns on Embodiment 2 of this invention. It is a table | surface which shows the rigidity value, natural frequency, and number of sheets of each leaf | plate spring of FIG. It is a graph which shows the dynamic rigidity of the laminated leaf | plate spring of FIG. It is a front view which shows the laminated leaf | plate spring which concerns on Embodiment 3 of this invention. It is sectional drawing which shows the vibration isolator which concerns on Embodiment 4 of this invention. It is a graph which shows the vibration transmission characteristic of the vibration isolator of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
A technique for stabilizing an object under a vibration environment is called a vibration isolation technique or a vibration isolation technique. The basic principle of vibration isolation is to reduce the transmission of vibration from the vibration source to the object and suppress the vibration of the object by arranging a vibration isolation device in the vibration transmission path between the vibration source and the object Is. Specific examples of the vibration isolator include a suspension for an automobile, an anti-vibration damper for a building, or a vibration isolator between a structure of an artificial satellite and an observation device.

  A vibration isolation system using a vibration isolator is represented by a dynamic model in which a vibration isolator represented by a spring device and a damper device is disposed between a vibration source that generates a forced displacement and an object. The vibration isolation performance of the vibration isolation device is evaluated by a frequency characteristic (hereinafter referred to as vibration transmission characteristic) of a vibration transmissibility defined by a displacement amplitude ratio of the object with respect to the forced displacement of the vibration source. Therefore, in designing a vibration isolator, first, based on the structural characteristics of the object and the vibration characteristic profile input from the vibration source, the vibration transfer characteristics for the vibration of the object to be within the required specification range. Next, the spring stiffness and the damper viscous damping coefficient that satisfy this vibration transfer characteristic are calculated by analysis. Finally, based on these values, the FEM analysis or the design formula is used to determine the spring device and Detailed design of the damper device will be implemented. In the evaluation stage, the validity of the design is evaluated by comparing the performance between the analysis results and the actual machine characteristics.

  However, the vibration isolation device designed by such a procedure often deteriorates the vibration isolation effect as compared with the theoretical characteristics. One reason for this is the surging phenomenon of the spring device. Surging is a resonance phenomenon of the spring device that appears when the excitation frequency of the vibration matches the natural frequency of the spring device. As the spring stiffness increases at the natural frequency of the spring device, the vibration transmissibility increases (vibration insulation characteristics deteriorate). This is because an actual spring device has a finite mass in a distributed parameter system, unlike an ideal dynamic model. Therefore, especially in a case where a large object is supported with low rigidity, the spring device inevitably increases in size and weight, so that the surging frequency is lowered and the vibration insulation characteristics tend to be noticeably deteriorated.

  In the first embodiment, a laminated leaf spring will be described as an example of a spring device. 1 is a front view showing a laminated leaf spring according to Embodiment 1 of the present invention. In the figure, the stacked leaf spring (spring device) includes 48 leaf springs (spring members) 1 stacked in the thickness direction, and a spacer 2 provided between the adjacent leaf springs 1. The number of leaf springs 1 is not limited to 48 and may be any other number.

  Each leaf spring 1 is connected in parallel via a spacer 2. The same kind of spring is used for each leaf spring 1. As a result, each leaf spring 1 has the same natural frequency.

  The leaf spring 1 is connected to the spacer 2 at both ends in one direction. Thereby, each leaf | plate spring 1 is restrained via the spacer 2 at one direction both ends. Moreover, the leaf | plate spring 1 has the distortion part 11 in the one direction center part. The strain generating portion 11 is elastically deformed when a load is applied to the leaf spring 1. Here, the one direction with respect to the leaf spring 1 is a leaf spring fixed to the vibration source 4 and a portion of the leaf spring 1 fixed to the object 3 when the leaf spring 1 is viewed from above. 1 is a direction along a straight line connecting the first portion and a direction along the leaf spring 1.

  When each leaf spring 1 is loaded in the plate thickness direction with respect to the overlap leaf spring so that the end on the vibration source 4 side is displaced with respect to the end on the object 3 side in the overlap leaf spring Are equally deformed. Here, the object 3 is an object to be stabilized on which a laminated leaf spring is installed, and the vibration source 4 is an object that applies a forced displacement to the object 3 via the laminated leaf spring.

  A clearance 5 is formed by the spacer 2 between the strain-generating portions 11 of the adjacent leaf springs 1. The dimension in the thickness direction of the spacer 2 is such that adjacent strain-generating portions 11 do not contact each other when a load is applied to each leaf spring 1. Accordingly, when the strain generating portions 11 are elastically deformed, the strain generating portions 11 of the adjacent leaf springs 1 are prevented from contacting each other. In other words, the clearance between the strain generating portions 11 of the adjacent leaf springs 1 is such that the strain generating portions 11 of the adjacent leaf springs 1 do not contact each other when the strain generating portion 11 is elastically deformed. 5 is formed.

  FIG. 2 is a block diagram showing a dynamic model of the laminated leaf spring of FIG. In the stacked leaf spring, when the strain generating portion 11 (FIG. 1) is elastically deformed, the strain generating portions 11 of the adjacent leaf springs 1 do not contact each other, so that the vibration source 4 is supported in parallel by the plurality of leaf springs 1. Can be represented by a dynamic model.

  FIG. 3 is a graph showing the dynamic rigidity of the laminated leaf spring of FIG. In FIG. 3, the dynamic rigidity (frequency characteristic of rigidity) of the laminated leaf spring is indicated by a solid line, and the dynamic rigidity of one leaf spring 1 is indicated by a broken line. In FIG. 3, the horizontal axis represents the frequency value, and the vertical axis represents the stiffness value. The stiffness value of the leaf spring 1 asymptotically approaches about 1000 N / m on the low frequency side, and has frequency dependence on the high frequency side. In particular, the stiffness value of the leaf spring 1 exhibits anti-resonance at 70 Hz and resonance at 200 Hz.

  On the other hand, the stiffness value of the laminated leaf spring is the total value of the stiffness values of the leaf springs 1 and, similarly to the stiffness value of the leaf spring 1, anti-resonance appears at 70 Hz and resonance occurs at 200 Hz. Appears. That is, in the laminated leaf spring, the natural frequency of the leaf spring 1, that is, the surging frequency of the leaf spring 1 becomes the surging frequency. Therefore, by adjusting the natural frequency of the leaf spring 1, the surging frequency of the laminated leaf spring can be easily adjusted.

  As described above, according to the laminated leaf spring according to Embodiment 1 of the present invention, the clearances 5 are formed between the strain-generating portions 11 of the adjacent leaf springs 1. The surging frequency of the leaf spring 1 becomes the surging frequency of the laminated leaf spring as it is. As a result, for example, when the profile of the vibration characteristics input to the laminated leaf spring is known in advance, the leaf spring is separated so that the natural frequency of the leaf spring 1 and the excitation frequency by the vibration source 4 are separated. It is only necessary to design 1 and the surging frequency of the laminated leaf spring can be easily adjusted. As a result, since the analysis of the whole laminated leaf spring becomes unnecessary, the design load can be greatly reduced.

Embodiment 2. FIG.
FIG. 4 is a front view showing a laminated leaf spring according to Embodiment 2 of the present invention, and FIG. 5 is a table showing the rigidity value, natural frequency and number of each leaf spring 1 of FIG. In the figure, the laminated leaf spring includes six types of leaf springs 1 having different natural frequencies. In addition, the laminated leaf spring includes eight leaf springs 1 of the same type. Therefore, the laminated leaf spring includes 48 leaf springs 1. In FIG. 5, leaf springs 1 having the same spring number have the same stiffness value and natural frequency (primary natural frequency). In addition, the kind of leaf | plate spring 1 is not restricted to six types, Other number of types may be sufficient. Further, the number of leaf springs 1 of the same type is not limited to 8 and may be other numbers. Therefore, the total number of leaf springs 1 is not limited to 48, and may be any other number. Further, the leaf springs 1 may be different leaf springs.

  In this example, the leaf springs are configured such that the leaf springs 1 are arranged so that the natural frequencies of the adjacent leaf springs 1 are different from each other. The laminated leaf spring may have a configuration in which the leaf springs 1 are arranged so that the leaf springs 1 having the same natural frequency are adjacent to each other.

  FIG. 6 is a graph showing the dynamic rigidity of the laminated leaf spring of FIG. In FIG. 6, the dynamic rigidity of the laminated leaf spring according to the second embodiment is indicated by a solid line, and the dynamic rigidity of the laminated leaf spring according to the first embodiment is indicated by a broken line. The laminated leaf spring according to Embodiment 1 has a static stiffness of about 50000 N / m by setting the rigidity of each leaf spring 1 to about 1000 N / m and the natural frequency to 200 Hz. On the other hand, the laminated leaf spring according to the second embodiment is composed of six kinds of leaf springs 1 having different natural frequencies so as to have a static rigidity of about 50000 N / m.

  Since the laminated leaf spring according to the second embodiment includes six types of leaf springs 1 having different natural frequencies, the number of surging frequencies corresponds to the number of types of leaf springs 1. However, since the number of leaf springs 1 of the same type is smaller in the laminated leaf spring according to the second embodiment than in the laminated leaf spring according to the first embodiment, the surging peak at each surging frequency is lowered. In other words, the laminated leaf spring according to the second embodiment can obtain an apparent damping effect against surging as compared with the laminated leaf spring according to the first embodiment. Other configurations are the same as those in the first embodiment.

  As described above, according to the laminated leaf spring according to the second embodiment of the present invention, since the plurality of types of spring plates 1 having different natural frequencies are provided, the laminated leaf spring according to the first embodiment and In comparison, surging can be suppressed.

  In addition, this laminated leaf spring is characterized by an external temperature environment and aging deterioration as compared with a spring device (see, for example, JP-A-08-210439) in which a viscoelastic member is attached to a coil spring to suppress surging. Since a viscoelastic member that fluctuates is not used, fluctuations in the suppression effect of surging depending on the external temperature environment and usage period are suppressed.

  Further, this laminated leaf spring is compared with a spring device (for example, Japanese Patent Application Laid-Open No. 2005-291424) that generates friction by bringing an elastic metal block into contact with the coil spring to suppress surging. In addition, since the surging portions 11 of the adjacent leaf springs 1 suppress surging without contacting each other, the effect of suppressing surging can be obtained even when the vibration level is small.

Embodiment 3 FIG.
FIG. 7 is a front view showing a laminated leaf spring according to Embodiment 3 of the present invention. In the figure, the laminated leaf spring further includes a damping member 6 filled in a clearance 5 between each strain-generating portion 11 of the adjacent leaf springs 1. The damping member 6 is composed of a viscoelastic body. As the damping member 6, a rubber-like or gel-like one is used.

  In this example, each leaf spring 1 is formed such that the natural frequencies of the adjacent leaf springs 1 are different from each other. In particular, the damping member 6 has a great damping effect on the shear strain. Therefore, avoiding the occurrence of shear deformation of the damping member 6 due to the adjacent leaf springs 1 vibrating in the same phase at a specific surging frequency. Can do. That is, when the shearing deformation appears in the damping member 6, the vibration of the leaf spring 1 can be attenuated. Other configurations are the same as those of the second embodiment.

  As described above, according to the laminated leaf spring according to Embodiment 3 of the present invention, the damping member 6 filled in the clearance 5 between the respective strain-generating portions 11 of the adjacent leaf springs 1 is further provided. Therefore, the further suppression effect of a surging peak can be acquired.

Embodiment 4 FIG.
FIG. 8 is a cross-sectional view showing a vibration isolator according to Embodiment 4 of the present invention, and FIG. 9 is a graph showing the vibration transfer characteristics of the vibration isolator of FIG. In the figure, the vibration isolator includes a plurality of overlapping leaf springs 7 and a damper device 8 connected in parallel with the overlapping leaf springs 7.

  The laminated leaf spring 7 is the same as the laminated leaf spring described in the third embodiment. The damper device 8 attenuates the vibration transmitted from the vibration source 4.

  The equation of motion of the vibration isolation system when the vibration isolator is used can be expressed by the following equation (1).

Here, m, c, k, x _P and x _B represent the mass of the object 3, the viscosity damping coefficient of the vibration isolator, the rigidity of the vibration isolator, the response displacement of the object, and the forced displacement of the vibration source 4. ing. When this is Laplace transformed under the following equation (2), the transfer function T (s) from the forced displacement of the vibration source 4 to the response displacement of the object 3 to be stabilized is expressed by the following equation (3) ).

  At this time, the vibration transmissibility of the vibration isolation system is defined by | T (jω) |, and the frequency characteristic can be represented by the Bode diagram of FIG. When an ideal laminated leaf spring 7 is assumed (when the spring stiffness is constant without frequency characteristics and surging does not occur), the vibration transmission characteristics are the characteristics indicated by the dotted lines in FIG. That is, after reaching the resonance point where the vibration transmissibility exceeds 1, a vibration insulation region where the vibration transmissibility is less than 1 appears in the high frequency range, and thereafter the vibration transmissibility decreases while maintaining a certain roll-off characteristic. To do.

  However, since the surplus leaf spring 7 generates surging, the spring stiffness has frequency characteristics. As a result, such an ideal vibration transmission characteristic is rarely obtained in an actual vibration isolator. The actual vibration transfer characteristic can be obtained by substituting the value of dynamic rigidity considering the frequency characteristic for the value of rigidity in the above equation (3). For example, in the case of the vibration isolator using the laminated leaf spring of the first embodiment, the vibration transfer characteristic as indicated by the broken line in FIG. 9 is calculated. That is, the vibration transmissibility increases to near 1 at the surging frequency of the laminated leaf spring, and the vibration insulation effect is greatly degraded.

  On the other hand, in the case of the vibration isolator using the laminated leaf spring 7 in the fourth embodiment, in the case of the vibration isolator using the laminated leaf spring of the first embodiment, the vibration was about 1 time around 200 Hz. As indicated by the solid line in FIG. 9, the transmission rate is reduced to about −30 dB by dispersing the surge peak in a band of 170 Hz to 220 Hz. That is, in the vibration isolator according to Embodiment 4, it is possible to suppress an increase in vibration transmissibility due to surging, which has been a problem in the high frequency range in the past.

  As described above, according to the vibration isolator according to Embodiment 4 of the present invention, the leaf spring 1 having the plurality of leaf springs 1 connected in parallel is provided, and the leaf spring 1 receives a load. And a plurality of types of leaf springs 1 having different natural frequencies. The clearances 5 are formed between the respective straining portions 11 of the adjacent leaf springs 1. Since the leaf spring 1 is configured to block vibration transmission from the vibration source 4, an increase in vibration transmission rate due to surging can be suppressed.

  In the fourth embodiment, the configuration of the vibration isolation device in which the laminated leaf spring 7 and the damper device 8 are connected in parallel has been described. However, the configuration is not limited to this, and for example, the laminated leaf spring without the damper device 8 is provided. 7 may be a vibration isolating device in which the damper device 8 is assembled in a complicated manner, such as a vibration isolating device having only 7 or a spring device connected in series to the damper device 8.

  In the fourth embodiment, the configuration of the vibration isolator in which the laminated leaf spring 7 is the same as the laminated leaf spring described in the third embodiment has been described. However, the laminated leaf spring 7 is described in the first embodiment. The structure of the vibration insulation apparatus which is the same as the laminated leaf spring or the laminated leaf spring described in the second embodiment may be used.

  Moreover, in each said embodiment, although the leaf | plate spring 1 was demonstrated as an example as a spring member, it is not restricted to this, For example, other spring members, such as a coil spring, may be sufficient.

  Moreover, in each said embodiment, although the laminated leaf | plate spring 7 was demonstrated as an example as a spring apparatus, not only this but another spring apparatus may be sufficient.

  DESCRIPTION OF SYMBOLS 1 Leaf spring (spring member), 2 Spacer, 3 Object, 4 Vibration source, 5 Clearance, 6 Damping member, 7 Lap leaf spring (Spring device), 8 Damper device, 11 Strain part

Claims (4)

A spring device comprising a plurality of spring members connected in parallel,
The spring member has a strain generating portion that is deformed by receiving a load,
A spring device characterized in that a clearance is formed between the strain generating portions of the adjacent spring members.   The spring device according to claim 1, comprising a plurality of types of the spring members having different natural frequencies.   The spring device according to claim 1, further comprising a damping member filled in the clearance between the strain-generating portions of the adjacent spring members. A spring device according to any one of claims 1 to 3 is provided,
The said spring apparatus interrupts | blocks the vibration transmission from a vibration source, The vibration insulation apparatus characterized by the above-mentioned.

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