JP3570204B2 - Inertia damper - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inertia damper using a magnetic fluid for reducing vibration of a rotating shaft of a rotating body.
[0002]
[Prior art]
Conventionally, as this kind of inertia damper, for example, there is a technique described on page 106 of "Introduction to Magnetic Fluid" (Shinichi Kamiyama, Sangyo Tosho).
[0003]
Hereinafter, an inertia damper using a magnetic fluid according to the related art will be described with reference to FIG. FIG. 3 is a schematic configuration sectional view of an inertia damper according to the related art.
[0004]
In FIG. 3, reference numeral 101 denotes a rotation shaft of a stepping motor (not shown), reference numeral 102 denotes a housing which is mounted on the rotation shaft 101 and rotates integrally with the rotation shaft 101, and the housing 102 is made of a non-magnetic material. .
[0005]
Reference numeral 103 denotes an inertial body that is housed through a gap in a hollow portion formed inside the housing 102, and the inertial body 103 is formed of a magnet.
[0006]
Reference numeral 104 denotes a magnetic fluid that fills a hollow portion in the housing 102, and the magnetic fluid 104 fills a gap between the inertial body 103 and an inner wall surface of the housing 102.
[0007]
Then, the inertial body 103 is in a state of floating without contacting the inner wall surface of the housing 102 by the magnetic levitation force provided by the magnetic fluid 104.
[0008]
Next, the operation of the inertia damper configured as described above will be described.
[0009]
When the rotating shaft 101 of the stepping motor rotates with acceleration, the housing 102 rotates together with the rotating shaft 101, but the inertial body 103 rotates independently of the housing 102 because the inertial body 103 is not restrained by the housing 102.
[0010]
As a result, a relative velocity is generated between the inner wall of the housing 102 and the surface of the inertial body 103, and the viscous resistance of the magnetic fluid 104 is generated in the rotation direction.
[0011]
This viscous resistance becomes a resistance to the relative movement between the housing 102 and the inertial body 103, and a damping force is generated. The damping force acts on the rotating shaft 101 to reduce the vibration caused by the rotation. Things.
[0012]
In order to make such a vibration reducing effect effective, it is necessary to appropriately select the value of the moment of inertia of the inertial body 103 and the value of the viscous damping coefficient indicating the magnitude of the viscous resistance.
[0013]
[Problems to be solved by the invention]
However, in the case of the above-described conventional technology, the following problems have occurred.
[0014]
In the inertia damper using a magnetic fluid as described above, when used in an environment with a large temperature change, it is necessary to use a magnetic fluid with a low viscosity so that the change in the viscosity damping coefficient due to the temperature change is small. .
[0015]
However, since the inertial body is formed of a disk of a certain thickness, the fluid resistance due to rotation is reduced, and the viscosity damping coefficient becomes smaller than the appropriate value in a low viscosity magnetic fluid. It was difficult to obtain a vibration reducing effect.
[0016]
The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object thereof is to reduce the viscosity damping coefficient even when a low-viscosity magnetic fluid having a small change in viscosity due to a temperature change is used. An object of the present invention is to provide a highly reliable inertia damper that suppresses vibration and effectively exerts a vibration reducing effect.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a housing fixed to a rotating shaft and having a hollow portion, a magnetic fluid filled in the hollow portion, and a magnetic fluid housed in the hollow portion, Inertia damper provided with a magnetic levitation force caused by magnetic inertia, and provided with concave and convex portions on the inner circumference of the housing and the outer circumference of the inertial body in the circumferential direction, respectively. The body is arranged.
[0018]
Therefore, in the circumferential direction, the opposing area between the housing and the inertial body increases, so that the viscous resistance increases.
[0019]
The inertial body may be formed by alternately stacking columnar magnets and magnetic bodies having different diameters.
[0020]
Therefore, the concave and convex portions can be provided on the outer periphery of the inertial body only by overlapping the columnar magnet and the magnetic body that do not require complicated processing.
[0021]
Further, the inertial body may be formed by stacking a columnar magnet and a magnetic body having an uneven portion on the outer periphery.
[0022]
Therefore, by processing a magnetic material that is easier to process than a magnet, it is possible to provide unevenness on the outer periphery of the inertial body.
[0023]
It is preferable that the magnetic material has a higher specific gravity than a magnet.
[0024]
Therefore, the moment of inertia can be increased as compared with the case where the inertial body is constituted only by the magnet.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to them unless otherwise specified. Absent.
[0026]
(First Embodiment)
With reference to FIG. 1, an inertia damper according to a first embodiment of the present invention will be described.
[0027]
FIG. 1 is a schematic configuration sectional view of an inertia damper according to a first embodiment of the present invention.
[0028]
In FIG. 1, reference numeral 1 denotes a rotating shaft of a rotating body such as a stepping motor (not shown), 2 denotes a disk-shaped housing which is mounted on the rotating shaft 1 and rotates integrally with the rotating shaft 1, and 2 denotes a non-rotating housing. It is made of a magnetic material, and has a hollow portion inside the housing 2.
[0029]
31 is a magnet, 32 is a magnetic material, and a plurality of magnets 31 and magnetic materials 32 are alternately stacked as shown in the figure to form an inertia body. This inertia body is formed inside the housing 2. It is accommodated in the hollow part with a gap.
[0030]
The inertial body has a plurality of magnets 31 and magnetic bodies 32 having different diameters, which are alternately overlapped with each other, so that the outer peripheral portion of the inertial body has irregularities.
[0031]
As described above, the irregularities can be easily formed on the outer peripheral portion of the inertial body simply by stacking the columnar magnet 31 and the magnetic body 32 which are relatively easy to process.
[0032]
Reference numeral 4 denotes a magnetic fluid filled in a hollow portion of the housing 2, and the magnetic fluid 4 fills a gap between the inertial body and the inner wall surface of the housing 2.
[0033]
The inertial body floats without contacting the inner wall surface of the housing 2 by the magnetic levitation force provided by the magnetic fluid 4.
[0034]
Here, the dimensions, the number, and the like of the magnets 31 and the magnetic bodies 32 are selected so that the magnetic levitation force provided by the magnetic fluid 4 does not fall below a value required to levitate and hold the inertial body in the housing 2. is there.
[0035]
In the present embodiment, a ring 5 formed of a non-magnetic material that has a cylindrical shape on the inner periphery of the housing 2, is provided with an uneven portion on the inner wall surface, and rotates integrally with the housing 2. Have.
[0036]
Further, by configuring the ring 5 so that it can be divided into a tile shape, assembly and processing of the damper becomes easy.
[0037]
The inertial body is arranged such that the concave and convex portions formed by the ring 5 on the inner periphery of the housing 2 and the concave and convex portions on the outer periphery of the inertial body are respectively inserted as shown in the figure.
[0038]
At this time, a predetermined gap is formed between the concave and convex portions.
[0039]
With the above-described configuration, since the respective concavities and convexities enter between the inner circumference of the housing 2 and the outer circumference of the inertial body, the facing area between the two increases, and the viscous resistance increases.
[0040]
Therefore, when the rotating shaft 1 rotates with acceleration, a large viscous resistance acts as a braking force on the rotating shaft 1, so that the vibration of the rotating shaft 1 can be sufficiently reduced.
[0041]
Therefore, even in the case of a low-viscosity magnetic fluid, the vibration reducing action can be obtained effectively, so that a stable vibration reducing action can always be obtained even in an environment with a large temperature change, and the reliability is improved.
[0042]
(Second embodiment)
FIG. 2 shows a second embodiment of the present invention. In the first embodiment, the configuration in which the cylindrical magnet and the magnetic body are overlapped to form the irregularities on the outer peripheral portion of the inertial body has been described. However, in the present embodiment, the cylindrical magnet and the irregularities are formed on the outer periphery. This shows a configuration in which the magnetic material provided with the portion is overlapped to form irregularities on the outer peripheral portion of the inertial body.
[0043]
Other configurations and operations are the same as those of the first embodiment, and therefore, the same components will be denoted by the same reference characters and description thereof will be omitted.
[0044]
FIG. 2 is a schematic sectional view of an inertia damper according to a second embodiment of the present invention.
[0045]
In the present embodiment, as shown in the figure, the inertial body is formed by laminating a columnar (disk) -shaped magnet 33 and a columnar (disk) -shaped magnetic body 34 having irregularities on the outer periphery. It consists of.
[0046]
As described above, by forming the concave and convex portions on the magnetic material which is relatively easy to process as compared with the magnet, only one magnet 33 is sandwiched between the two magnetic materials 34 as shown in FIG. Unevenness can be formed, and only one magnet 33 is required.
[0047]
However, the magnetic force of the magnet 33 needs to be larger than a predetermined value.
[0048]
With the above configuration, the same effects as those of the first embodiment can be obtained.
[0049]
(Other embodiments)
In each of the above-described embodiments, if the magnetic material constituting the inertial body has a higher specific gravity than the magnet, the weight (assuming the same size) is greater than when the inertial body is constituted only by the magnet. Can be increased, the moment of inertia increases, and the size of the apparatus can be relatively reduced.
[0050]
【The invention's effect】
In the present invention, in the circumferential direction, the uneven portion is provided on the inner circumference of the housing and the outer circumference of the inertial body, and the inertial body is arranged in a state in which the respective uneven portions enter, so in the circumferential direction, The opposing area between the housing and the inertial body is increased, so that the viscous resistance can be increased.
[0051]
Therefore, even if a low-viscosity magnetic fluid is used, the reduction of the viscous damping coefficient can be suppressed and the effect of reducing vibration can be effectively exerted. improves.
[0052]
As for the inertial body, irregularities can be easily provided on the outer periphery of the inertial body simply by stacking columnar magnets and magnetic bodies having different diameters, which do not require complicated processing.
[0053]
In addition, the inertial body can be easily provided with irregularities on the outer periphery of the inertial body by stacking a cylindrical magnet and a magnetic body having irregularities on the outer periphery of the magnetic body which is easier to process than the magnet. In this case, only one magnet may be used.
[0054]
If the specific gravity of the magnetic body is made larger than that of the magnet, the moment of inertia can be increased as compared with the case where the inertia body is constituted only by the magnet, and the device can be downsized.
[Brief description of the drawings]
FIG. 1 is a schematic configuration sectional view of an inertia damper according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration sectional view of an inertia damper according to a second embodiment of the present invention.
FIG. 3 is a schematic sectional view of a configuration of an inertia damper according to the related art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotation shaft 2 Housing 31 Magnet 32 Magnetic body 33 Magnet 34 Magnetic body 4 Magnetic fluid 5 Ring

Claims (4)

A housing fixed to the rotating shaft and having a hollow portion,
A magnetic fluid filled in the hollow portion,
An inertia body accommodated in the hollow portion, and levitated by a magnetic levitation force of a magnetic fluid, comprising:
The inertial body is composed of a magnet and a magnetic body,
An inertia damper characterized in that irregularities are provided on the inner periphery of the housing and the outer periphery of the inertial body in the circumferential direction, respectively, and the inertial body is arranged in a state in which the irregularities enter. The inertia damper according to claim 1, wherein the inertial body is formed by alternately stacking columnar magnets and magnetic bodies having different diameters. The inertia damper according to claim 1, wherein the inertial body is formed by stacking a cylindrical magnet and a magnetic body having an uneven portion on an outer periphery. The inertia damper according to claim 2, wherein the magnetic material has a specific gravity greater than that of a magnet.

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