JP2010090966A - Damping structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a damping structure for giving sufficient vibration damping operation even to a rotating body while suppressing the vibration and noises without being influenced by temperature and frequency conditions. <P>SOLUTION: In the damping structure for the rotating body 1, the rotating body 1 has a hollow part 5, the hollow part 5 is filled with a plurality of granules 6 and a viscoelastic body 7, and the granular bodies 6 are essentially evenly dispersed in the viscoelastic body 7. The rotating body 1 is a shaft 2 of a rotor 10 that constitutes a motor, or a gear 9. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a damping structure for a rotating body such as a rotor shaft and gears used in a motor.

  Conventionally, a rotating body such as a shaft of a rotor and a gear constituting a motor may generate vibrations and noises during its rotation, which has been a problem. In the case of the rotor shaft, the electromagnetic force is unbalanced during rotation, and in the case of the gear, the meshing vibration occurs. In order to solve the problem, it is conceivable to provide a vibration damping material by providing a vibration damping material to the rotating bodies.

  Conventional damping materials used for imparting damping properties include viscoelastic materials and granular impact dampers using granular materials, but for rotor shafts and rotating bodies such as gears. When these damping materials are employed, it is possible to exemplify adopting a method of obtaining a damping action by forming a hollow portion in these rotating bodies and incorporating the damping material in the hollow portion.

  When adopting a viscoelastic material as a vibration damping material built in a hollow part, the viscoelastic material has a problem that the dynamic viscoelastic material characteristics change depending on the temperature and frequency used, and in order to solve the problem, By blending viscoelastic materials with different temperature characteristics and frequency characteristics, it is necessary to be able to cope with a wide temperature range and frequency range. However, there is a limit to the correspondence, and it cannot be said that the material is suitable for use as a damping material for a rotating body such as a rotor shaft or gear.

  On the other hand, it is also conceivable to employ a granular material impact damper using the granular material described in Patent Documents 1 to 3 as a damping material. The technique described in Patent Document 1 is a technique that uses a granular material to effectively suppress radiated sound from the surface of the main body of a turbofluid machine, piping, a coupling cover, and the like. The technique described in is a technique for suppressing vibration caused by imbalance in the drive system of a railcar bogie using a granular material and reducing vehicle interior noise caused by the vibration. This technique is a technique for obtaining a sheet-shaped damping material and damping panel having high damping performance using a granular material.

  When this granular material is used as a damping material, a certain clearance is provided in the hollow portion of the rotating body to incorporate the granular material, but when the rotational speed of the rotating body increases, the centrifugal force causes the granular material However, it cannot be moved at all because it is pressed against the inner wall of the hollow portion on the outer periphery of the rotating body. Therefore, in the case of the non-rotating structure described in Patent Documents 1 to 3, the damping action obtained by the collision between the granular bodies and the friction between the granular bodies and the inner wall cannot be obtained in the case of the rotating body. End up.

JP-A-8-93693 JP 2005-289370 A JP 2001-12543 A

  The present invention has been made as a solution to these conventional problems, and even with a rotating body, it can obtain a sufficient vibration-damping action, and can be vibrated without being affected by temperature conditions and frequency conditions. It is an object of the present invention to provide a vibration control structure capable of suppressing generation of noise and noise.

  The invention according to claim 1 is a vibration damping structure of a rotating body, the rotating body has a hollow portion, and the hollow portion is filled with a plurality of granular bodies and viscoelastic bodies, The granular body is a vibration damping structure characterized in that the granular body is substantially uniformly dispersed in the viscoelastic body.

  The invention according to claim 2 is characterized in that the rotating body is a shaft of a rotor constituting a motor, and the hollow portion filled with a plurality of granular bodies and a viscoelastic body is formed. It is the vibration suppression structure described.

  A third aspect of the present invention is the vibration damping structure according to the second aspect, wherein the vibration damping structure is formed only at a central portion in the axial direction of the shaft.

  The invention according to claim 4 is the vibration damping structure according to claim 2 or 3, which is formed between the outer cylinder and the inner cylinder forming the shaft.

  The invention according to claim 5 is the vibration damping structure according to claim 1, wherein the rotating body is a gear, and the hollow portion filled with a plurality of granular bodies and a viscoelastic body is formed. is there.

  A sixth aspect of the present invention is the vibration damping device according to the fifth aspect, wherein the hollow portions are a plurality of hollow portions having substantially the same shape and formed at substantially equal intervals in the circumferential direction of the gear. Structure.

  The invention according to claim 7 is characterized in that the mass and volume of the granular body and the viscoelastic body incorporated in the hollow portion, and the density of the granular body in the viscoelastic body are substantially the same in all the hollow portions. The vibration damping structure according to claim 6.

  The invention according to claim 8 is the vibration damping structure according to any one of claims 1 to 7, wherein the viscoelastic body is any one of silicone oil, silicone rubber, and silicone gel.

  According to the vibration damping structure of the first aspect of the present invention, when the rotating body rotates, the granular body in the hollow portion moves somewhat in the outer circumferential direction of the rotating body by the centrifugal force, but in the hollow portion together with the granular body Since the viscoelastic body is filled, the granular body vibrates at that position without being pressed against the inner wall of the hollow portion, and as a result, the stress generated in the viscoelastic body propagates through the viscoelastic body, Since the damping performance is exhibited by mutual interference with the vibration of the granular material, a sufficient damping effect can be obtained even with a rotating body. In addition, generation of vibrations and noise can be suppressed without being affected by temperature conditions and frequency conditions.

  According to the vibration control structure described in claim 2 of the present invention, even if vibration is generated in the rotor constituting the motor, generation of vibration and noise can be suppressed by the vibration control action. Furthermore, since the hollow part filled with the granular material and the viscoelastic body is formed on the shaft of the rotor having a low magnetic flux density, the performance of the motor is not impaired.

  According to the vibration damping structure described in claim 3 of the present invention, the hollow portion filled with the granular material and the viscoelastic body does not need to be formed over the entire length of the shaft of the rotor, and the amount of the granular material and the viscoelastic body to be used is reduced. Moreover, since the hollow part filled with the granular material and the viscoelastic body is formed at the axial center part of the long shaft, it is balanced and does not adversely affect the rotation of the rotor.

  According to the vibration damping structure of the fourth aspect of the present invention, the hollow portion filled with the granular body and the viscoelastic body can be easily formed in the shaft of the rotor.

  According to the vibration damping structure of the fifth aspect of the present invention, vibration and noise generated by the rotation of the gear can be suppressed by the vibration damping action.

  According to the vibration damping structure of the sixth aspect of the present invention, since the hollow portions having substantially the same shape and having a plurality of granular bodies are arranged at substantially equal intervals over the entire circumference of the gear, the vibration is reliably controlled with good balance. The vibration action can be exhibited, and the generation of vibration and noise can be more reliably suppressed.

  According to the vibration damping structure of the seventh aspect of the present invention, the vibration damping action can be more reliably exhibited, and the generation of vibration and noise can be further reliably suppressed.

  According to the vibration-damping structure of claim 8 of the present invention, by using any one of silicone oil, silicone rubber, and silicone gel, in which viscoelastic properties hardly change due to temperature change, as a viscoelastic body, The vibration control function can be reliably exerted without any influence.

  Hereinafter, the present invention will be described in more detail based on embodiments shown in the accompanying drawings. First, an embodiment in which the vibration damping structure of the present invention is employed for a rotor shaft will be described.

  FIG. 1 shows an embodiment in which the vibration damping structure of the present invention is adopted for a rotor shaft, (a) is a perspective view, and (b) is a cross-sectional view taken along line AA of (a). . FIG. 2 shows an embodiment different from FIG. 1 in the case where the vibration damping structure of the present invention is adopted for the shaft of the rotor, (a) is a perspective view, and (b) is a cross-sectional view taken along line AA of (a). FIG.

  FIG. 3 is a front view showing an outline of a motor in which a stator is incorporated as viewed from the end face. 2 is a shaft, 10 is a rotor, and 11 is a stator.

  A shaft 2 of a rotor 10 constituting the motor shown in FIG. 1 is composed of a shaft main body 2 a formed of a long cylindrical inner cylinder 3 and an outer cylinder 4 that is mounted around the axial center of the inner cylinder 3. ing. The outer cylinder 4 is shorter than the inner cylinder 3, and a cylindrical hollow portion 5 is formed between the outer cylinder 4 and the inner cylinder 3. Both end surfaces of the hollow portion 5 are closed by annular end caps 8 provided on both end surfaces of the outer cylinder 4. The hollow portion 5 is filled with a plurality of granular bodies 6 and viscoelastic bodies 7 without any gaps. The granular body 6 is dispersed substantially uniformly in the viscoelastic body 7, and there is no unevenness of the granular body 6 in the hollow portion 5.

  Thus, since the granular material 6 is filled in the viscoelastic body 7 in a substantially uniform manner in the hollow portion 4, the shaft 2 of the rotor 10, which is the rotating body 1, rotates, and the rotational speed is high. Even if the centrifugal force acts, the granular material 6 is not pressed against the inner wall of the hollow portion 5 on the outer peripheral side of the shaft 2 and cannot move at all.

  When the shaft 2 of the rotor 10 rotates, the granular material 6 moves somewhat from the stationary state toward the outer periphery of the shaft 2 due to the centrifugal force, but the vibration is not suppressed and the granular material 6 vibrates. Thus, the stress generated in the viscoelastic body 7 propagates through the viscoelastic body 7 and interacts with the vibration of another granular body 6 to exhibit vibration damping.

  As the viscoelastic body 7, oil having a high viscosity (viscosity of 100,000 to 1,000,000 cst or more), liquid rubber, an elastomer which is crosslinked to suppress flow, and the like can be used. Among these, silicone oil, silicone rubber, or silicone gel whose viscoelastic properties (complex elastic modulus) hardly change with temperature is preferably used. Furthermore, it is optimal to use a cold resistant gel that does not cure even at -50 ° C. That is, the viscoelastic body 7 is desirably a viscoelastic body 7 having high heat resistance and low temperature / frequency dependency. In order to adjust the elastic coefficient, a large number of bubbles may be provided in the viscoelastic body.

  The material of the granular material 6 is not particularly limited, but the material can be easily obtained by being formed from a material mainly composed of iron, aluminum, copper, or ceramic. It is desirable because the granular material 6 can be formed relatively easily.

  When the granular body 6 is made of a nonmagnetic material such as a material mainly composed of ceramic, the performance of the motor is not affected. On the other hand, when the granular material 6 is soft magnetic powder such as iron powder or iron-base alloy powder, the rotor 6 is used for the shaft 2 of the rotor 10 formed by compacting soft magnetic powder such as iron powder or iron-base alloy powder. It is possible to use the same material as the forming material 10, and it is possible to save time and labor for material procurement. The shape of the granular body 6 is preferably a sphere.

  The reason why the hollow portion 5 filled with the plurality of granular bodies 6 and the viscoelastic body 7 is formed not on the rotor 10 body but on the shaft 2 of the rotor 10 is that the shaft 2 has a magnetic flux density higher than that of the rotor 10 body. This is because the motor performance is not impaired even if the hollow portion 5 is formed because the position is relatively low.

  The shaft 2 of the rotor 10 constituting the motor shown in FIG. 2 is composed of a shaft main body 2 a composed of a long cylindrical outer cylinder 4 and an inner cylinder 3 inserted and fixed at the axial center of the outer cylinder 4. ing. The inner cylinder 3 is shorter than the outer cylinder 4, and a cylindrical hollow portion 5 is formed between the outer cylinder 4 and the inner cylinder 3. Both end surfaces of the hollow portion 5 are closed by an annular end cap 8 provided between the outer cylinder 4 and the inner cylinder 3. The hollow portion 5 is filled with a plurality of granular bodies 6 and viscoelastic bodies 7 without any gaps. The granular body 6 is dispersed substantially uniformly in the viscoelastic body 7, and there is no unevenness of the granular body 6 in the hollow portion 5.

  The operations obtained in the embodiment shown in FIG. 2 and other configurations are the same as those in the embodiment shown in FIG.

  As described above, the embodiment in which the lengths of the inner cylinder 3 and the outer cylinder 4 are different is shown in FIGS. 1 and 2, but both the inner cylinder 3 and the outer cylinder 4 may be the same length. In this case, the hollow portion 5 filled with the plurality of granular bodies 6 and the viscoelastic body 7 is formed over the entire length of the shaft 2 of the rotor 10.

  Next, an embodiment in which the vibration damping structure of the present invention is adopted for a gear will be described.

  4A and 4B show an embodiment in which the vibration damping structure of the present invention is employed in a gear, where FIG. 4A is a front view and FIG. 4B is a cross-sectional view taken along line AA in FIG. In addition, the circle formed at substantially equal intervals in the circumferential direction of FIG. 4A is a curved bulge, and a hollow portion 5 is formed inside thereof.

  The gear 9 shown in FIG. 4 is a spur gear having teeth formed on the outer periphery thereof. A plurality of hollow portions 5 having substantially the same cross-sectional shape are formed on the entire circumference of the gear 9 so as to be arranged at substantially equal intervals in the circumferential direction. In the hollow portions 5, a plurality of granular bodies 6 and viscoelasticity are formed. The body 7 is filled without any gaps. The granular body 6 is dispersed substantially uniformly in the viscoelastic body 7, and there is no unevenness of the granular body 6 in the hollow portion 5.

  In this way, the hollow body 5 is filled with the granular material 6 in the viscoelastic body 7 so as to be dispersed substantially evenly. Therefore, the gear 9 that is the rotating body 1 rotates, and the rotational speed increases and the centrifugal force is increased. Even if force is applied, the granular material 6 is not pressed against the inner wall of the hollow portion 5 on the outer peripheral side of the gear 9 and cannot move at all.

  When the gear 9 rotates, the granular material 6 moves somewhat from the stationary state in the outer peripheral direction of the gear 9 due to the centrifugal force, but the vibration is not suppressed, and the granular material 6 vibrates. The stress generated in the elastic body 7 propagates through the viscoelastic body 7 and interacts with the vibration of another granular body 6 to exhibit damping properties.

  The granular body 6 and the viscoelastic body 7 are preferably formed of the same material as described above in the embodiment in which the vibration damping structure of the present invention is adopted for the shaft 2 of the rotor 10.

  Further, the mass and volume of the granular body 6 and the viscoelastic body 7 incorporated in the hollow portion 5, the density of the granular body 6 in the viscoelastic body 7, and the shape of each granular body 6 are all the hollow portions 5. It is desirable from the standpoint of damping efficiency that the same.

  In addition, although the case where the spur gear is used as the gear 9 has been described, it is needless to say that the vibration damping structure of the present invention can also be adopted in other gears such as a helical gear, an angle gear, and a bevel gear.

1 shows an embodiment in which the vibration damping structure of the present invention is adopted for a shaft of a rotor, (a) is a perspective view, and (b) is a sectional view taken along line AA of (a). FIG. 5 shows different embodiments when the vibration damping structure of the present invention is adopted for a shaft of a rotor, (a) is a perspective view, and (b) is a cross-sectional view taken along line AA of (a). It is a front view which shows the outline | summary which looked at the motor incorporating a stator from the end surface. 1 shows an embodiment in which the vibration damping structure of the present invention is employed in a gear, where (a) is a front view and (b) is a cross-sectional view taken along line AA of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotating body 2 ... Shaft 2a ... Shaft body 3 ... Inner cylinder 4 ... Outer cylinder 5 ... Hollow part 6 ... Granular body 7 ... Viscoelastic body 8 ... End cap 9 ... Gear 10 ... Rotor 11 ... Stator

Claims (8)

  A vibration damping structure for a rotating body, wherein the rotating body has a hollow portion, and the hollow portion is filled with a plurality of granular bodies and a viscoelastic body, the granular body being the viscoelastic body Damping structure characterized by being distributed almost evenly inside.   The damping structure according to claim 1, wherein the rotating body is a shaft of a rotor constituting a motor, and the hollow portion filled with a plurality of granular bodies and a viscoelastic body is formed.   The vibration control structure according to claim 2, wherein the hollow portion is formed only in an axial center portion of the shaft.   4. The vibration damping structure according to claim 2, wherein the hollow portion is formed between an outer cylinder and an inner cylinder forming the shaft.   2. The vibration damping structure according to claim 1, wherein the rotating body is a gear, and the hollow portion filled with a plurality of granular bodies and a viscoelastic body is formed.   6. The vibration damping structure according to claim 5, wherein the hollow portions are a plurality of hollow portions having substantially the same shape formed at substantially equal intervals in a circumferential direction of the gear.   The mass and volume of the granular body and the viscoelastic body incorporated in the hollow portion, and the density of the granular body in the viscoelastic body are substantially the same in all the hollow portions. Shaking structure.   The vibration damping structure according to any one of claims 1 to 7, wherein the viscoelastic body is one of silicone oil, silicone rubber, and silicone gel.

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