JP2013126072A - Vibration isolator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the vibration occurring steadily when a mobile moves, and the impact occurring suddenly.SOLUTION: A vibration isolator 1 includes a U-shaped leaf spring 2 which is interposed when a camera is installed on a mobile while directing the aperture 4 in the horizontal direction, and a viscoelastic body 3. The leaf spring 2 includes a support-plate 8 provided to support the camera on the outside of the U-shape at the linear portion thereof, a fixing plate 7 arranged to face the support-plate 8 at the linear portion of the U-shape so as to be fixed to the mobile on the outside of the U-shape, and a leaf spring material 9 provided at the curved portion of the U-shape so as to connect the support-plate 8 and the fixing plate 7. The viscoelastic body 3 is provided between the support-plate 8 and the fixing plate 7, so as to absorb the biasing force of the leaf spring 2 in the stretching direction thereof.

Description

  The present invention relates to a vibration isolator, and more particularly to a vibration isolator for a photographing camera installed on a moving body.

  Conventionally, as a vibration isolator, for example, a device that absorbs vibration by an elastic member, a device that measures vibration by various sensors such as an accelerometer, and performs vibration isolation by an electric circuit or a control device based on the measurement result are known. Yes. For example, in Patent Document 1, since an image shake is generated in an image taken by a camera suspended on the tip of a crane arm, a vertical vibration is suppressed by a coiled spring, or a shock absorber. Therefore, a vibration isolator that suppresses vibration transmitted from the arm to the camera by suppressing horizontal vibration is disclosed.

  Further, for example, Patent Document 2 discloses a camera with an anti-shake function (camera shake correction function) that moves in the direction opposite to the camera shake direction by the same distance as the amount of camera shake based on the angular velocity detected by the gyro sensor built in the camera. It is disclosed.

JP 2008-263514 A JP 2007-171708 A

No conventional vibration isolator combined with a suspension or shock absorber can absorb vibrations from camera images when used on a moving body.
Further, for example, a device that measures vibration by an accelerometer or the like and electrically isolates the vibration causes a delay time until the amount of vibration is calculated and fed back.
In addition, when each method is combined, the mechanism becomes large and complicated, which is not suitable from the viewpoint of cost.

  In addition, when installing a camera to be shaken on a moving object, it is necessary to take anti-vibration measures in consideration of the characteristics of the moving object. For example, when the moving body is a vehicle on which a person rides, the effect of the tire functioning as a damper, the effect of having a dedicated anti-vibration mechanism for providing a comfortable ride to the person apart from the anti-vibration device, and the road surface Since there are vibration effects and the like coming from, it is difficult to properly separate these effects, making vibration analysis difficult.

  In addition, a vehicle such as a general bicycle with strong vibrations generates vibrations intermittently or constantly during traveling due to the influence of road noise according to road traveling, tire noise of the vehicle itself, and the like. Further, when the road surface is in a bad state, for example, when the vehicle passes over a hole on the road, the tire falls into the hole, so that a shock is suddenly generated. For example, the magnitude of vibration of the wave (first shock wave) at the moment of falling into the hole is very large. In short, the vibration of a photographing camera mounted on a vehicle such as a bicycle is a vibration component over a wide band such as the vibration of an initial shock (first shock wave) or the vibration that is steadily generated. It is very difficult to reduce and absorb with a vibration isolator.

  The present invention has been made in view of the above-described problems, and provides a vibration isolator capable of reducing vibrations that are constantly generated and suddenly generated as the moving body moves. The task is to do.

  In order to solve the above-mentioned problems, a vibration isolator according to claim 1 of the present invention is provided to be interposed when a photographing camera is installed on a moving body, and is a U-shaped plate whose opening is directed horizontally. A vibration isolator comprising a spring part and a viscoelastic body, wherein the leaf spring part is provided so as to support the photographing camera on the outside of the U-shape in one linear portion of the U-shape; A mounting portion disposed so as to be opposed to the support portion at the other straight portion of the U-shape and attached to the movable body outside the U-shape; and the support portion and the attachment at a curved portion of the U-shape And a viscoelastic body provided between the support portion and the mounting portion.

According to such a configuration, in the vibration isolator, a viscoelastic body having viscoelasticity having a characteristic different from that of the spring can absorb a vibration component in a band different from that of the leaf spring portion. That is, when the vibration from the moving body is transmitted to the vibration isolator, the vibration of the leaf spring portion of the vibration isolator is longer than that of the viscoelastic body, but the vibration is greatly shaken slowly. At this time, although the vibration of the viscoelastic body of the vibration isolator absorbs the urging force in the expansion and contraction direction of the leaf spring portion, the vibration oscillates smaller and faster than the leaf spring portion, but the vibration ceases immediately.
Therefore, in a vibration isolator installed in a moving body such as a bicycle, an instantaneous static vibration response to an initial impact (first shock wave) vibration is made mainly by a leaf spring portion, and road noise is mainly made by a viscoelastic body. It is possible to absorb vibrations that occur constantly or intermittently due to (including tire noise). As a result, it is possible to absorb the vibration of the image acquired by the photographing camera installed on the bicycle or the like.

  The vibration isolator according to claim 2 is the vibration isolator according to claim 1, wherein a support plate for forming the support portion is predetermined at one end portion of the leaf spring material for forming the arc portion. The attachment plate forming the attachment portion is fixed to the other end portion of the leaf spring material via a predetermined connection member.

  According to this configuration, since the leaf spring material forming the arc portion of the leaf spring portion is a separate member from the support plate and the mounting plate, the vibration isolator selects a desired leaf spring material according to the moving body and the photographing camera. By doing so, it becomes easy to change the design of the leaf spring portion having a desired spring constant as appropriate.

  Further, the vibration isolator according to claim 3 is the vibration isolator according to claim 1 or 2, wherein the viscoelastic body is formed in a columnar shape, and the width of the leaf spring portion with respect to the opening. It was decided to be provided at a position that is symmetrical with respect to the direction.

  According to this configuration, the vibration isolator is formed in a columnar shape so that the material is reduced while maintaining the strength of the viscoelastic body, and the support portion and the attachment portion are arranged in the width direction of the leaf spring portion. It is possible to absorb the urging force in the expansion / contraction direction of the leaf spring portion while supporting it with a good balance.

  The vibration isolator according to claim 4 is the vibration isolator according to any one of claims 1 to 3, wherein the leaf spring portion includes a weight of the photographing camera including an accessory. The spring constant was calculated to be 3 kg or less.

  According to such a configuration, even if the vibration isolator is installed in a relatively lightweight and mobile body such as a bicycle, the burden on the mobile body and the driver can be reduced.

ただし、δ_yは撮影カメラの重心の位置における支持板の鉛直方向のたわみ、Ｐは撮影カメラの重心の位置における荷重、Ｒは板バネ材の円弧の半径、Ｌは板バネ材の円弧の中心から撮影カメラの重心の位置までの水平距離、Ｅは板バネ材のヤング率、Ｉは板バネ材の断面二次モーメント、ｂは板バネ材の幅、ｔは板バネ材の厚さを示す。 The vibration isolator according to claim 5 is the vibration isolator according to any one of claims 2 to 4, wherein the spring constant of the leaf spring portion regards the support plate as a rigid body. It was that it is designed as represented by the k _y of the following formula (1) when.

Where δ _y is the deflection in the vertical direction of the support plate at the position of the center of gravity of the photographing camera, P is the load at the position of the center of gravity of the photographing camera, R is the radius of the arc of the leaf spring material, and L is the center of the arc of the leaf spring material The horizontal distance from the center of gravity of the photographing camera to the position of the center of gravity of the camera, E is the Young's modulus of the leaf spring material, I is the cross-sectional secondary moment of the leaf spring material, b is the width of the leaf spring material, and t is the thickness of the leaf spring material. .

According to such a configuration, when the vibration isolator is installed in a moving body such as a bicycle, for example, the natural vibration of the leaf spring portion corresponding to the designed static spring constant k _y of the leaf spring portion and the vibration thereof. According to the transmissibility, an instantaneous static vibration response can be made to the vibration of the initial shock (first shock wave).

According to the first aspect of the present invention, the vibration isolator can reduce vibrations that are constantly generated and suddenly generated as the moving body moves.
According to the invention described in claim 2, the vibration isolator can easily change the design of the static spring constant of the leaf spring portion as appropriate.
According to the invention described in claim 3, the vibration isolator can absorb the biasing force in the expansion and contraction direction of the leaf spring portion while the viscoelastic body supports the support portion and the attachment portion in a balanced manner in the width direction of the leaf spring portion.

According to invention of Claim 4, even if it installs in the mobile body which is comparatively lightweight and travels by human power, the vibration isolator can reduce the burden on a mobile body and a driver.
According to the fifth aspect of the present invention, the vibration isolator can appropriately change the design of the performance of the instantaneous static vibration response to the vibration of the initial shock (first shock wave).

It is a perspective view which shows typically the state which attached the vibration isolator which concerns on embodiment of this invention to the imaging | photography camera. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows typically the vibration isolator which concerns on embodiment of this invention, Comprising: (a) is a perspective view of the whole apparatus, (b) is a side view of a leaf | plate spring part. It is a disassembled perspective view which shows typically the structure of the vibration isolator which concerns on embodiment of this invention. It is a schematic diagram for demonstrating operation | movement of the vibration isolator which concerns on embodiment of this invention, Comprising: (a) is a time change of the magnitude | size of a vibration when sudden vibration generate | occur | produces, (b) is (a ) Shows the time variation of the magnitude of vibration when the vibration isolator is used. It is a figure which shows typically a state when receiving the load from the imaging camera which the vibration isolator which concerns on embodiment of this invention carries, (a) is a side view, (b) shows a top view Yes. It is a side view which shows a virtual state when a viscoelastic body is removed from the state of the vibration isolator shown to Fig.5 (a). It is a figure which shows typically a state when a load is removed from the state of the vibration isolator shown in FIG. 5, wherein (a) shows a side view and (b) shows a top view. It is a graph which shows an example of a vibration transmissibility as a performance of the vibration isolator which concerns on embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for implementing a vibration isolator of the present invention will be described in detail with reference to the drawings. Note that the size and positional relationship of members and the like shown in the drawings may be exaggerated for clarity of explanation.

[Outline of vibration isolator]
The anti-vibration device 1 is provided when the photographing camera 200 is installed on a moving body.
In this embodiment, the moving body is described as a bicycle (without a suspension) as an example. In the example shown in FIG. 1, the vibration isolator 1 is installed on a rod-like support arm 103 attached to a handle bar 102 in front of the frame 101 of the bicycle 100.

The photographing camera 200 is assumed to be a general small camera marketed for consumer use as an example. Here, the term “small” refers to a size that is 3 kg or less, preferably 1 kg or less at most, including camera accessories.
The photographing camera 200 is installed on the bicycle 100 via the vibration isolator 1 with the camera lens 201 facing the bicycle 100 side. Thereby, the photographing camera 200 can photograph a bicycle driver.

[Configuration of vibration isolator]
As shown in FIG. 2A, the vibration isolator 1 mainly includes a U-shaped leaf spring portion 2 and a viscoelastic body 3. Hereinafter, when a viscoelastic body having a cylindrical shape is particularly distinguished, it is represented as a viscoelastic body 3a. In FIG. 2A, since the photographing camera 200 is not mounted, the U-shaped opening in the leaf spring portion 2 is widened toward the outside. When mounted so as to be horizontal, the two U-shaped straight portions are designed to be parallel. FIG. 2B shows a side view of the leaf spring portion 2 as designed. Although the illustration of the photographing camera 200 is omitted in FIG. 2B, it is assumed that it is installed.

<Leaf spring part>
The leaf spring portion 2 has a material, a thickness, a width, a length, a free height, a spring constant, and the like determined according to the use conditions of the vibration isolator 1. In addition, the design value of the spring constant in a predetermined use condition will be described in an embodiment described later.
As shown in the side view of FIG. 2B, the leaf spring portion 2 has a U-shaped linear portion 5 arranged up and down in a state where the U-shape is tilted sideways and the U-shaped opening 4 is directed in the horizontal direction. A U-shaped curved portion 6 is arranged opposite to the opening 4.

As shown in FIGS. 2 (a) and 2 (b), the leaf spring portion 2 includes a mounting plate 7 (mounting portion) provided on one (upper) straight portion 5 of the U shape, and a mounting plate 7. The support plate 8 (support portion) provided on the other (lower) straight portion 5 of the U-shape and the support plate 8 and the mounting plate 7 are provided so as to be connected at the U-shaped curved portion 6. Plate spring material 9 (arc portion). Here, the leaf spring material 9 is shown in katakana to distinguish it from the leaf spring portion 2.
In this embodiment, the direction in which the opening 4 is arranged (left in FIG. 1) and the direction of the camera lens 201 of the photographing camera 200 are the same, but may be opposite.

≪Mounting plate (mounting part) ≫
The attachment plate 7 is provided so as to be attached to the bicycle 100 on the U-shaped linear portion 5 outside the U-shape (lower side in FIG. 1). Specifically, screw holes 11 are formed in the mounting plate 7 as shown in FIG. A screw 104 is provided on the surface (upper surface) of the support arm 103 facing the outer surface (lower surface) of the mounting plate 7. As a result, the screw 104 is screwed into the screw hole 11 of the mounting plate 7, whereby the vibration isolator 1 is installed on the bicycle 100 via the support arm 103.

  The material of the mounting plate 7 is not particularly limited. When the vibration isolator 1 is installed on the bicycle 100 as in the present embodiment, it may be exposed to wind and rain outdoors, and therefore, for example, a material having corrosion resistance such as stainless steel is preferable. The shape of the mounting plate 7 is not particularly limited, but is formed in, for example, a substantially square flat plate shape.

≪Support plate (support part) ≫
The support plate 8 is provided so as to support the photographing camera 200 on the outside of the U-shape (upper side in FIG. 1) in the U-shaped linear portion 5. In the present embodiment, the support plate 8 is disposed above the mounting plate 7. Specifically, screw holes 21 are formed in the support plate 8 as shown in FIG. A screw 202 is provided on the surface (lower surface) of the photographing camera 200 facing the outer surface (upper surface) of the support plate 8. Thereby, the imaging camera 200 is installed in the bicycle 100 via the vibration isolator 1 by screwing the screw 202 into the screw hole 21 of the support plate 8.

  The material of the support plate 8 is not particularly limited, but is preferably stainless steel or the like, for example, like the mounting plate 7. Although the shape of the support plate 8 is not specifically limited, For example, it is formed in a substantially square flat plate shape. The support plate 8 and the mounting plate 7 may have the same shape and the same shape so that the leaf spring portion 2 can be used upside down.

≪Plate spring material (arc part) ≫
The leaf spring material 9 is fixed by a mounting member 7 and a support plate 8 and a predetermined connecting member such as a screw. Specifically, as shown in FIG. 3, screw holes 31 and 32 are formed in the leaf spring material 9 at one end portion (lower flat portion) sandwiching a curved surface portion having a predetermined curvature. In addition, screw holes 33 and 34 are formed in the other end (upper plane portion). As shown in FIG. 3, screw holes 12 and 13 are formed in the mounting plate 7, and screw holes 22 and 23 are formed in the support plate 8. As a result, the screws 41 and 42 are screwed into the screw holes 31 and 32 on the lower flat portion of the leaf spring material 9 and the screw holes 12 and 13 of the attachment plate 7, so that the attachment plate 7 is attached to the leaf spring material 9. Fixed. Further, the screws 51 and 52 are screwed into the screw holes 33 and 34 in the upper flat portion of the plate spring material 9 and the screw holes 22 and 23 of the support plate 8, so that the support plate 8 is fixed to the plate spring material 9. The

  The material of the leaf spring material 9 is a general material, and examples thereof include spring steel such as beryllium copper and phosphor bronze, stainless steel, and the like. Although the value of the width of the leaf spring material 9 is not particularly limited, for example, it is preferable that the value is the same as that of the mounting plate 7 or the support plate 8. When the vibration isolator 1 is installed on the handle bar 102 of the bicycle 100 as in the present embodiment, lateral vibration occurs when the driver opens the handle of the bicycle. Therefore, the leaf spring material 9 can be widened in this way. The twisting in the width direction of the leaf spring material 9 can be prevented and positioned.

  If the leaf spring material 9 is replaced with a coil spring, it is necessary to provide a plurality of coil springs at equal intervals on the U-shaped curved portion 6 of the leaf spring portion 2, and the number of components increases. Or preventing twisting and positioning in the width direction as desired. On the other hand, in this embodiment, such a situation can be avoided by providing the leaf spring material 9 having a predetermined width in the U-shaped curved portion 6 of the leaf spring portion 2.

<Viscoelastic body>
The viscoelastic body 3 is provided between the support plate 8 and the mounting plate 7.
The viscoelastic body 3 has a material, a shape, a dynamic spring constant, and the like determined according to the use conditions of the vibration isolator 1. In addition, the design value of the dynamic spring constant under a predetermined use condition will be described in an example described later.

  The viscoelastic body 3 has a property that combines both viscosity and elasticity, and has a predetermined storage shear modulus. The viscoelastic body 3 is configured by forming a polymer substance such as plastic in a columnar shape. Here, the viscoelastic body is, for example, synthetic resin (plastic, polyvinyl chloride, polyethylene, phenol resin, etc.), silicone resin (silicon rubber, silicone oil), synthetic fiber (nylon, vinylon, polyester, polyethylene) as a synthetic polymer. For example, terephthalate) or synthetic rubber formed in a columnar shape is used. As an example of a specific product, the viscoelastic body 3 is a viscoelastic body made of an acrylic polymer having excellent weather resistance, which is used in a VEM structural damper sold by Sumitomo 3M Limited. be able to.

  A viscoelastic body has fluidity like a fluid and exerts a force due to viscous resistance (a force proportional to the deformation speed is generated), and has an elastic property like a spring. It is a polymer material that exhibits dynamic behavior with the characteristics of exerting proportional force. The viscoelastic body has a low viscous resistance when the deformation speed is slow, and the spring element shows dominant behavior, and when a high deformation speed is applied like an impact force, the viscous resistance element is large. Therefore, a large reaction force is generated. The viscoelastic body has a structure in which long molecular chains are entangled in the polymer material used, and when the deformation is applied, the chain will stretch or contract, and the frictional resistance between the molecules at that time Exerts a vibration energy absorption effect. The viscoelastic body generates frictional resistance between molecules, and as a result, the whole ripens slightly and is converted into thermal energy to absorb vibration.

In this embodiment, the vibration isolator 1 is provided with two columnar viscoelastic bodies 3a and 3a as an example. The viscoelastic bodies 3a and 3a are provided so as to be bonded to the support plate 8 and the mounting plate 7 by welding or an adhesive. Here, the viscoelastic bodies 3 a and 3 a are provided at predetermined positions at positions that are symmetrical in the width direction of the leaf spring material 9 with respect to the U-shaped opening 4. By arranging the viscoelastic bodies 3a and 3a in this manner, the viscoelastic bodies 3a and 3a support the support plate 8 and the mounting plate 7 in a balanced manner in the width direction of the leaf spring portion 2 in the expansion and contraction direction of the leaf spring portion 2. Can absorb the biasing force. The viscoelastic bodies 3a, 3a are adjusted by the type of resin, the installation area, and the sheet thickness and absorbed by the support plate 8 in order to absorb the urging force of the leaf spring portion 2 in the expansion / contraction direction. Corresponding to the range of weight supported by the camera 200, it can be set as appropriate. The height of the cylinder of the viscoelastic body 3a is equal to the interval between the upper and lower linear portions 5 and 5 of the leaf spring portion 2 (mounted with a camera) shown in FIG. Yes. The cross-sectional area of the cylinder is not particularly limited, but is preferably 100 mm ² or more when it has a natural shape as designed, for example, because it is easy to process the viscoelastic body.

[Operation of vibration isolator]
<Premise>
In the bicycle 100 in which the photographing camera 200 is installed with the vibration isolator 1 interposed, road noise (including tire noise) is intermittently generated during traveling. That is, when the bicycle 100 is traveling on a normal road, steady vibration is generated in the bicycle 100. Further, when the bicycle 100 comes into contact with an obstacle on a road, for example, an impact is suddenly generated. That is, when the bicycle 100 is traveling on a normal road, suddenly larger vibration than usual is generated.

  Here, for simplicity, it is assumed as an example that the bicycle 100 passes over one hole on the road. An example of the time change of the magnitude of vibration at this time is schematically shown in FIG. Note that the waveform shown in FIG. 4A exaggerates the magnitude of vibration. As shown in FIG. 4A, the magnitude of the vibration of the wave (first shock wave) at the moment when the tire of the bicycle 100 falls into the hole on the road is very large. It can be seen that in the next and subsequent waves that have passed one cycle of the waveform, the magnitude of vibration is moderated to some extent, but continues to vibrate.

<Comparative reference example>
As an example for comparison, an image shot by a shooting camera 200 installed without the vibration isolator 1 interposed in the bicycle 100 is assumed. Here, assuming that one cycle of vibration is approximately the same as the frame of the video shot by the shooting camera 200, a video that is greatly shifted corresponding to the vibration of the first shock wave is shot in the first frame of the video. The A video image that continues to vibrate is captured even after the second frame of the video image.

  When broadcasting an image acquired by the in-vehicle photographing camera 200, a sense of discomfort in a TV image that is felt by a viewer who watches the broadcast is often felt due to a large shake of the camera and intermittent slight vibration of the camera. . Viewers who watch videos taken in this way are more likely to experience video sickness. That is, it is known that when a viewer views an image in which the influence of vibration continues for, for example, 5 frames or more, the user may feel uncomfortable, eyes may become tired, or may feel light.

<Effect of vibration isolator>
As described above, the vibration isolator 1 of the present embodiment includes the leaf spring portion 2 having a predetermined spring constant and the viscoelastic bodies 3a and 3a having a predetermined dynamic spring constant.
Compared to the viscoelastic bodies 3a and 3a, the leaf spring part 2 has a characteristic that vibrations continue to oscillate for a long time because the vibration transmissibility is large, but vibrations oscillate slowly and greatly because the natural frequency is low.
The viscoelastic bodies 3a and 3a have a characteristic that, compared to the leaf spring portion 2, the vibrations are quickly and slightly swayed because of its high natural frequency, but the vibrations are quickly stopped because of their low vibration transmissibility.

  FIG. 4B schematically shows an example of the temporal change in the magnitude of vibration when the imaging camera 200 is installed with the vibration isolator 1 interposed in the bicycle 100 as in the present embodiment. The broken line shown in FIG. 4B is the same as the waveform shown in FIG. 4A, and the solid line shown in FIG. 4B shows the effect of the vibration isolator 1. Note that the waveform shown in FIG. 4B exaggerates the magnitude of vibration.

  As shown in FIG. 4B, the magnitude of vibration of the wave (first shock wave) at the moment when the tire of the bicycle 100 falls into the hole on the road is suppressed to be small. This is due to the action of the vibration of the leaf spring portion 2 slowly and greatly shaking. Further, as shown in FIG. 4B, it can be seen that the vibration converges after a half period of the waveform. This is due to the action that the vibration of the viscoelastic bodies 3a, 3a stops immediately.

  Therefore, as in the comparative reference example, an image shot by the shooting camera 200 installed on the bicycle 100 with the vibration isolator 1 interposed is assumed. Here, assuming that one period of vibration is approximately the same as the frame of the video shot by the shooting camera 200, a video in which the vibration is greatly suppressed is shot in the first frame of the video regardless of the first shock wave. The Then, in the second and subsequent frames of the video, a video in which the vibration due to the impact falling in the hole is converged is shot. Viewers who watch videos taken in this way are less likely to experience video sickness. In other words, since the influence of vibration can be suppressed to less than 5 frames, it is possible to prevent the viewer from feeling uncomfortable, eyes tired, or feeling wobbled.

[Design example of vibration isolator]
<Spring constant>
A design example of the vibration isolator 1 will be described with reference to FIG.
FIG. 5A is a side view of the image stabilizer 1 when a not-shown photographing camera is mounted on the support plate 8 of the image stabilizer 1, and FIG. 5B is a top view thereof. At this time, as shown in FIG. 5A, the cylindrical viscoelastic bodies 3a, 3a have a natural shape as designed, and the support plate 8 and the mounting plate 7 of the leaf spring portion 2 are parallel to each other. It is assumed that the U-shaped arc part is a semicircle. The radius R of the arc of the leaf spring material 9 indicates the radius on the outer peripheral surface of the leaf spring material 9.

In FIG. 5A, the position g ₁ indicates the position of the center of gravity of the photographing camera on the support plate 8, and the position g ₂ indicates the position of the center of gravity of the photographing camera on the mounting plate 7. An imaginary line connecting the positions g ₁ and g ₂ indicates a load center line. At the positions g ₁ and g ₂ , the spring constant (static spring constant) of the leaf spring portion 2 can be calculated from the load P caused by the photographing camera and accessories and the support plate 8.

FIG. 6 shows a state in which the columnar viscoelastic bodies 3a and 3a are removed from the equilibrium state balanced with the load P as shown in FIG. Here, the support plate 8 is regarded as a rigid body, and the support plate 8 itself is not bent. In this case, let δ _y be the deflection in the vertical direction of the support plate 8 at the imaginary line connecting the positions g ₁ and g ₂ .
The spring constant of the leaf spring portion 2 can be designed as represented by k _y in the following equation (1) using the load P and the deflection δ _y .

ただし、δ_yは撮影カメラの重心の位置における支持板８の鉛直方向のたわみ、Ｐは撮影カメラの重心の位置における荷重、Ｒは板バネ材９の円弧の半径、Ｌは板バネ材９の円弧の中心Ｏから撮影カメラの重心の位置までの水平距離、Ｅは板バネ材９のヤング率、Ｉは板バネ材９の断面二次モーメント、ｂは板バネ材９の幅、ｔは板バネ材９の厚さを示す。

Where δ _y is the deflection in the vertical direction of the support plate 8 at the position of the center of gravity of the photographing camera, P is the load at the position of the center of gravity of the photographing camera, R is the radius of the arc of the leaf spring material 9, and L is the radius of the leaf spring material 9. The horizontal distance from the center O of the arc to the position of the center of gravity of the camera, E is the Young's modulus of the leaf spring material 9, I is the cross-sectional secondary moment of the leaf spring material 9, b is the width of the leaf spring material 9, and t is the leaf The thickness of the spring material 9 is shown.

<Dynamic spring constant>
FIG. 7A shows a side view of a state in which a camera (not shown) being mounted is temporarily removed from an equilibrium state balanced with the load P as shown in FIG. Is shown in FIG. In this case, as shown in FIG. 7A, since the weight of the photographing camera is reduced from the load P, the leaf spring portion 2 is extended, and the opening of the leaf spring portion 2 is widened toward the outside. Along with this, the columnar viscoelastic bodies 3a, 3a are stretched by being pulled in the axial direction of the column and become slightly thin.

The dynamic spring constants of the viscoelastic bodies 3a and 3a are as follows: the storage shear modulus of the viscoelastic body is G ^* , the total cross-sectional area of the viscoelastic bodies 3a and 3a is A, and the axial center in the viscoelastic body 3a is When the length is H, it can be designed as represented by k _v ′ in the following formula (4).

  Here, since the viscoelastic bodies 3a and 3a are extended, the cross-sectional areas are not equal at both ends where the viscoelastic bodies 3a and 3a adhere to the upper and lower plates 7 and 8 and the vicinity of the center. In this case, the cross-sectional area of the viscoelastic body 3a indicates an average value of the cross-sectional area of the entire column. In this example, the total cross-sectional area A is a cross-sectional area obtained by doubling the cross-sectional area of each viscoelastic body 3a. Since the viscoelastic bodies 3a and 3a are elongated, the cross-sectional shape seen through in FIG. 7B is shown as a substantially elliptical shape.

<Natural frequency of vibration isolator>
The natural frequency f _n of the vibration isolator 1 includes the spring constant k _y of the leaf spring portion 2 shown in the above formula (1) and the dynamic spring constant k _v ′ of the viscoelastic bodies 3a and 3a shown in the above formula (4). From the load P and the gravitational acceleration G, it can be calculated by the following equation (5).

  As described above, according to the vibration isolator 1 of the present embodiment, an instantaneous static vibration response to the vibration of the initial shock (first shock wave) is made mainly by the leaf spring portion 2, and mainly the viscoelastic body 3a. , 3a can absorb vibrations that occur constantly or intermittently due to road noise (including tire noise). Moreover, the vibration isolator 1 of the present embodiment realizes the above vibration isolating mechanism with a relatively simple configuration of the leaf spring portion 2 and the viscoelastic bodies 3a and 3a, and the vibration isolating mechanism becomes large and complicated. There are also advantageous effects in terms of cost.

  Further, the vibration isolator 1 according to the present embodiment can absorb vibration vibration of an image acquired by the photographing camera 200 by being interposed when the photographing camera 200 is installed on a moving body such as a bicycle. For example, a sense of incongruity in a television image is often felt by a large shaking of the photographing camera and intermittent slight vibration. On the other hand, the vibration isolator 1 of the present embodiment, for example, transmits the first shock wave out of vibration components (10 to 30 Hz in the case of a bicycle without a suspension) generated in the vertical direction of the in-vehicle camera. Suppresses the slow vibration of 5Hz or less due to the repulsive action of the spring part 2 and suppresses the intermittent vibration and the steady vibration following the first shock wave to the vibration of 2Hz or less by the viscoelastic bodies 3a and 3a. can do. Therefore, according to the vibration isolator 1 of the present embodiment, there is an excellent effect that, in a camera-captured video on a vehicle, a realistic camera shooting can be realized without the viewer feeling uncomfortable such as video sickness.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to this. For example, in the vibration isolator 1, the U-shaped leaf spring portion 2 has been described in a form in which the leaf spring material 9 is sandwiched between the support plate 8 and the mounting plate 7 as shown in FIG. The support plate 8 may be fixed to the lower surface side of the plate 9, the mounting plate 7 may be fixed to the upper surface side of the plate spring material 9, and the plate spring material 9 may sandwich the support plate 8 and the mounting plate 7. Moreover, although the U-shaped leaf | plate spring part 2 demonstrated as a thing provided with the attachment board 7, the support plate 8, and the leaf | plate spring material 9 as another member, you may form it with an integral member.

  In this embodiment, in the vibration isolator 1, the number of the columnar viscoelastic bodies 3a is two, but may be one or three or more. For example, the arrangement of the two cylinders may be the depth direction instead of the width direction. Further, the design of the interval between the cylinders can be changed as appropriate. The shape of the viscoelastic body 3 is not limited to a cylindrical shape, and the shape of the upper surface of the column may be an ellipse, a square, or other polygonal shape, or a shape having an inclined surface such as a truncated cone or a truncated pyramid. May be.

In the present embodiment, the photographing camera 200 is installed in the direction for photographing the driver of the bicycle, but may be installed in the direction for photographing the scenery in front of the driver.
In the present embodiment, the moving body is described as a bicycle. However, the moving body to which the present invention is applied is, for example, as a vehicle without a suspension by a human power such as a baby carriage or a nursing wheelchair in addition to the bicycle. It may be a moving body that moves or a moving body that moves by electric drive.

  Further, as a mobile body that travels in land, sea, and the air, it is needless to say that the present invention may be applied to, for example, a motorcycle, a boat, a helicopter, and the like. Moreover, since the present invention is suitable for a lightweight small camera, the present invention is not limited to a moving body on which a person rides, and may be installed on a radio control model or the like.

  In the present embodiment, in the U-shaped leaf spring portion 2, the support plate 8 that supports the photographing camera 200 is disposed above the attachment plate 7. However, the support plate 8 is disposed below the attachment plate 7. Also good. In this case, the support arm 103 shown in FIG. 1 is attached to the bicycle 100 so as to be rotated 180 degrees with respect to the handle bar 102, so that the support plate 8 suspends (supports) the photographing camera 200 and the driver's You can shoot the scenery in front. As another example in which the support plate 8 that supports the photographing camera 200 is disposed below the attachment plate 7, the attachment plate 7 is screwed to the bottom surface of the body such as a helicopter directly or via a support arm or the like. Also good.

  In the present embodiment, the vibration isolator for the photographing camera has been described. However, in addition to the photographing camera as a visual sensor, for example, the vibration of a measuring device used for various types of sensing, or a general load mounted on the support plate 8 is used. It is also possible to apply to vibration isolation.

In order to confirm the effect of the present invention, the performance of the vibration isolator according to the present embodiment was measured.
For this reason, not only the design on the desk but also the static spring constant k _y is changed by fine adjustment, and the vibration state in the image of the driving face of the driver of the bicycle 100, that is, the camera 200 The vibration state was investigated. In the following, SI converted values are also shown.

As an example, the condition that the load P is 0.2 [kgf / cm] (= 196 [N / m]) was assumed. This indicates that the total weight of the photographing camera 200 and its accessories and the support plate 8 of the vibration isolator 1 is 200 [g] (= 0.2 [kg]).
In this case, the vibration of the photographed image is reduced and a good video without video sickness is obtained in the vibration isolator 1 in the parameters of the equations (2) and (3). , L, b, and t were the following dimensions, and the U-shaped leaf spring portion 2 was produced. The design values of the viscoelastic bodies 3a and 3a will be described later. The design value at this time is referred to as an example.

R = 1.0 [cm] (= 1.0 × 10 ⁻² [m])
L = 4.0 [cm] (= 4.0 × 10 ⁻² [m])
b = 4.0 [cm] (= 4.0 × 10 ⁻² [m])
t = 0.03 [cm] (= 3.0 × 10 ⁻⁴ [m])

<About spring constant>
In the embodiment, stainless steel (SUS) was used as the material of the leaf spring material 9. Therefore, the following values were used as the Young's modulus E of the leaf spring material 9.
E = 2.1 × 10 ⁶ [kgf / cm ² ] (= 206 [GPa])
As a result of the calculation of the formula (3), the following value was obtained as the cross-sectional secondary moment I of the leaf spring material 9.
^{I = bt 2/12 = 9} × 10 -6 [cm 4] (= 9 × 10 -14 [m 4])
As a result of the calculation of the equation (2), the following value was obtained as the vertical deflection δ _y of the support plate 8 at the position of the center of gravity of the photographing camera.
δ _y = 0.72 [cm] (= 7.2 × 10 ⁻³ [m])
As a result of the calculation of the formula (1), the following value was obtained as the spring constant k _y of the leaf spring portion 2.
k _y = 0.28 [kgf / cm] (= 270 [N / m])

  Although not shown, as a comparative example, the spring constant of the leaf spring portion 2 is 0.2 [kgf / cm] or a value that is twice as large as the load P = 0.2 [kgf / cm]. The video that was designed and photographed as (0.4 [kgf / cm]) was not satisfactory.

<About the dynamic spring constant>
In the example, since the measurement result of the cross-sectional area of the viscoelastic body 3a in the vibration isolator 1 was 0.7 [cm ² ], the total cross-sectional area among the parameters of the equation (4) is A = 1.4 [ cm ² ]. Of the parameters of the formula (4), the measurement result of the length at the center in the axial direction when the viscoelastic body 3a is extended was H = 2.5 [cm].
As the viscoelastic body constituting the viscoelastic body 3a, one having a storage shear modulus G ^* having the following value under a predetermined temperature and a predetermined frequency condition (20 ° C., 10 Hz) was used.
G ^* ≈2.0 [kgf / cm ² ]
Therefore, as a result of the calculation of the equation (4), the following values were obtained as the dynamic spring constants k _v ′ of the viscoelastic bodies 3a and 3a.
k _v ′ = 1.12 [kgf / cm] (= 1100 [N / m])
Note that the initial design values of the spring constant and the dynamic spring constant may change due to aging.

<About the natural frequency of the vibration isolator>
The natural frequency f _n of the vibration isolator 1 is calculated from the above equation (5) from the spring constant k _y , the dynamic spring constant k _v ′, the load P, and the gravitational acceleration G. As a result, f _n = 13 2 [Hz].
The performance of the vibration isolator 1 at this time is shown in FIG. The horizontal axis of the graph in FIG. 8 indicates the frequency of vibration input to the vibration isolator 1, and the vertical axis indicates the vibration transmission rate in the vertical direction of the vibration isolator 1. Here, the vibration transmissibility indicates a ratio of response acceleration to input acceleration.

As shown in FIG. 8, the vibration isolator 1 of the present embodiment exhibits a vibration isolating effect against vibrations of approximately 10 to 30 [Hz]. Among these, the value of the vibration transmissibility was about 1.5 at the resonance frequency (13.2 [Hz]).
Although illustration is omitted, as a result of measuring the performance of the coil spring and the vibration isolating rubber as a conventional general vibration isolating mechanism in the same manner, the coil spring transmits vibration when the resonance frequency is 4 [Hz]. The value of the rate was about 10, and the vibration isolating rubber had a value of about 5 at the resonance frequency (8 [Hz]).

Further, as shown in FIG. 8, the vibration isolator 1 of this embodiment has a vibration transmissibility value of 1 when the frequency is 20 [Hz] and a vibration transmissibility value of 30 [Hz]. Therefore, it can be seen that vibration can be effectively prevented against vibration of about 20 to 30 [Hz].
In addition, although illustration is abbreviate | omitted, a coil spring has the anti-vibration effect with respect to the vibration of about 5-10 [Hz], and anti-vibration rubber has the anti-vibration effect with respect to the vibration of about 11-16 [Hz]. did.

The vibration characteristic of the present embodiment is that the vibration of the vibration isolator 1 is largely swayed slowly (for example, 5 [Hz] or less) with respect to the vibration of the instantaneous shock (first shock wave) mainly due to the characteristic of the leaf spring 2 alone. The magnitude of vibration of the first shock wave is reduced. Therefore, it is suitable for absorbing the first shock wave of the shock that occurs suddenly, such as when the bicycle receives an impact during traveling.
Further, as a characteristic of the viscoelastic body 3a, 3a alone of the vibration isolator 1, since the vibration transmissibility of the viscoelastic body is small, the vibration is immediately shaken by a wave after an instantaneous shock (first shock wave). It stops (for example, it vibrates slowly at 2 [Hz] or less and stops). Therefore, it is suitable when a relatively high frequency vibration occurs intermittently or constantly as in a bicycle.

  As described above, the vibration isolator 1 according to the present embodiment can simultaneously reduce vibrations constantly generated and suddenly generated as a moving body such as a bicycle is moved by one vibration isolation mechanism. I was able to confirm that I could do it. Note that when a vibration of 10 to 30 Hz occurs intermittently or regularly as in a bicycle, a coil spring or a vibration-proof rubber is not suitable.

DESCRIPTION OF SYMBOLS 1 Vibration isolator 2 Leaf spring part 3,3a Viscoelastic body 4 Opening 5 Straight line part 6 Curved part 7 Mounting plate (mounting part)
8 Support plate (support part)
9 Leaf spring material (arc part)
11-13, 21-23, 31-34 Through-hole 41, 42, 51, 52 Screw (connection member)
100 Bicycle (moving body)
101 Frame 102 Handlebar 103 Support Arm 104 Screw 200 Photographing Camera 201 Camera Lens 202 Screw

Claims (5)

An anti-vibration device provided with a U-shaped leaf spring portion and a viscoelastic body, which is provided when the photographing camera is installed on a moving body and has an opening oriented in the horizontal direction,
The leaf spring portion is
A support portion provided so as to support the photographing camera on the outside of the U-shape in one linear portion of the U-shape;
A mounting portion disposed so as to face the support portion in the other straight portion of the U-shape and provided to be attached to the movable body outside the U-shape;
An arc portion provided to connect the support portion and the attachment portion in a U-shaped curved portion;
The vibration isolator is provided between the support portion and the attachment portion.   The leaf spring portion has a support plate forming the support portion fixed to one end portion of the leaf spring material forming the arc portion via a predetermined connecting member, and the other leaf spring material The vibration isolator according to claim 1, wherein a mounting plate forming the mounting portion is fixed to an end portion via a predetermined connecting member.   The said viscoelastic body is formed in the column shape, and is provided in the position used as the left-right symmetry which is the width direction of the said leaf | plate spring part with respect to the said opening. Anti-vibration device.   4. The prevention according to claim 1, wherein the leaf spring portion has a spring constant calculated on the assumption that the weight of the photographing camera including an accessory is 3 kg or less. 5. Shaker. The spring constant of the plate spring portion, claims 2 to 4, characterized in that it is designed to the support plate as represented by the k _y of the following formula (1) when considered as a rigid body The vibration isolator as described in any one of.

Where δ _y is the deflection in the vertical direction of the support plate at the position of the center of gravity of the photographing camera, P is the load at the position of the center of gravity of the photographing camera, R is the radius of the arc of the leaf spring material, and L is the center of the arc of the leaf spring material The horizontal distance from the center of gravity of the photographing camera to the position of the center of gravity of the camera, E is the Young's modulus of the leaf spring material, I is the cross-sectional secondary moment of the leaf spring material, b is the width of the leaf spring material, and t is the thickness of the leaf spring material. .

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