JP4190803B2 - Vibration control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration damping device for suppressing vibration.
[0002]
[Prior art]
Conventionally, a screw compressor S1 shown in FIG. 11 is known. The screw compressor S1 has a so-called semi-hermetic structure in which the compressor casing 51 of the compressor main body C and the motor casing 52 of the motor M are integrally coupled, and the compressor casing 51 meshes with each other. A pair of male and female screw rotors are rotatably housed, and one of the rotor shafts is coupled to an output shaft in the motor casing 52. The screw compressor S1 is installed on the base plate 54 via the vibration-proof rubber 53, and is devised to suppress the generation of noise by directly transmitting the vibration of the screw compressor S1 to the base plate 54.
[0003]
Furthermore, a screw compressor S2 shown in FIG. 12 is known. This screw compressor S2 is the same as the screw compressor S1 shown in FIG. 11 except that a dynamic vibration absorber 55 is provided, and parts common to each other are denoted by the same reference numerals. Description is omitted.
The dynamic vibration absorber 55 is formed of a spring 56 erected on the motor casing 52 and a mass body 57 held by the spring 56. The dynamic vibration absorber 55 disperses the resonance frequency of the screw compressor S2, thereby avoiding resonance.
[0004]
[Problems to be solved by the invention]
In the case of the conventional screw compressor S <b> 1 (FIG. 11) described above, the motor speed at which resonance occurs varies depending on the hardness of the vibration-proof rubber 53. That is, as shown by the solid line in FIG. 13 (horizontal axis: motor rotational speed, vertical axis: compressor amplitude), when the vibration isolating rubber 53 has a small hardness, resonance occurs when the motor rotational speed is N1. In contrast, when the hardness is large, as indicated by a broken line in FIG. 13, the motor rotation number at which resonance occurs is N2, which is larger than N1. Therefore, as long as the screw compressor S1 is used with the motor rotation speed N1, resonance is avoided by hardening the vibration-proof rubber 53. However, when the motor M is an inverter motor, the rotation speed changes. In this case, there is a problem that resonance occurs.
[0005]
On the other hand, in the case of the screw compressor S2 (FIG. 12), the natural frequency is dispersed into two by the dynamic vibration absorber 55. That is, as shown by a solid line in FIG. 14 (horizontal axis: motor rotation speed, vertical axis: compressor amplitude), when the dynamic vibration absorber 55 is not attached, resonance occurs when the rotation speed is N1. On the other hand, as shown by the broken line in FIG. 14, when the dynamic vibration absorber 55 is attached, resonance occurs when the motor rotation speed is N3 smaller than N1 and N4 larger than N1. Accordingly, similarly to the above, when the motor M is an inverter motor, the screw compressor S2 may change to N3 or N4 when the motor M is an inverter motor. In this case, resonance occurs. Occurs.
[0006]
Thus, in the past, resonance has been avoided by changing the natural frequency of the object to be damped, but when the motor rotation speed changes as in the case of using an inverter motor, for example, at the minimum On the other hand, the maximum is 10 times that, and the range of change is wide, and it is very difficult to remove the natural frequency changed from this range. For this reason, the motor rotational speed may coincide with the changed natural frequency, and at this time, resonance occurs, causing a failure of the vibration control object.
The present invention has been made with the object of eliminating such conventional problems, and it is intended to provide a vibration damping device capable of suppressing the vibration of the vibration damping object regardless of its natural frequency. It is what.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the first invention is such that a compressor casing of a compressor body and a motor casing of an inverter motor are integrally coupled, and a pair of male and female screw rotors meshing with each other are included in the compressor casing. A vibration damping device is provided in a compressor that is rotatably housed and one of which has a rotor shaft coupled to an output shaft in the motor casing, and projects from the motor casing in substantially the same direction as the output shaft. The damping portion provided in the motor casing and vibrates integrally with the motor casing, and an initial position closer to the non-vibrating position of the damping portion than the position where the damping portion can collide with the damping portion when vibrating. Te, to keep away from him from the damping unit, or this is displaceably held closer, and a is recoverable way normally urged the initial position masses above Attenuating portion is formed from rod-like body which projects in a direction perpendicular to the vibration direction in the motor casing, said mass body is disposed between the end portion of the motor casing and the rod-like body structure It was.
[0008]
The second invention, in addition to the configuration of the first invention, the damping unit is provided with a flange portion overhanging from the upper Symbol rod body, it has a structure of being pressed at all times the flange portion by the mass governor roots.
[0009]
In the third invention, in addition to the configuration of either the first or second invention, the mass body is formed by stacking a plurality of plate-like members that can slide relative to each other.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a vibration damping device 1A according to a first embodiment of the present invention. The vibration damping device 1 </ b> A includes an attenuation unit 11 and a mass body 12. The attenuating unit 11 protrudes from a damping object 13, for example, a casing of a screw compressor, and vibrates integrally with the damping object 13. The mass body 12 seems to be far from or close to the damping portion 11 at an initial position that is closer to the non-vibrating position of the damping portion 11 than a position where it can collide with the damping portion 11 when the damping portion 11 vibrates. It is held by a spring 14 so as to be displaceable, and is always urged by this spring 14 so as to be able to return to the initial position. The spring 14 is attached to the stationary part 15.
[0011]
And if the vibration of the damping part 11 integrated with the damping object 13 becomes intense, the damping part 11 and the mass body 12 come to collide. As a result, the vibration energy of the vibration control object 13 is converted into the collision energy lost by the collision and the vibration energy of the mass body 12, and the vibration of the vibration control object 13 is suppressed regardless of its natural frequency. .
[0012]
FIG. 3 shows a vibration damping device 1B according to the second embodiment of the present invention, and parts common to the vibration damping device 1A shown in FIGS. 1 and 2 are given the same numbers.
In this vibration damping device 1 </ b> B, mass bodies 12 are disposed on both sides of the attenuation unit 11. As described above, the present invention does not limit the number of mass bodies 12, and includes a vibration damping device in which three or more mass bodies 12 are arranged for one attenuation portion 11. In particular, if the damping unit 11 does not only perform one-dimensional (linear) vibration, but also two-dimensional (for example, circular) or three-dimensional (for example, spiral including torsion) vibration. It is desirable to dispose a plurality of mass bodies 12 at each position of the directional component to be suppressed among the directional components included in the two-dimensional and three-dimensional vibrations.
[0013]
FIG. 4 shows a vibration damping device 1C according to the third embodiment of the present invention, and portions common to the vibration damping device 1A shown in FIGS.
In the vibration damping device 1 </ b> C, the attenuation unit 11 is provided so as to protrude from the vibration damping object 13 in the lateral direction. Further, the mass body 12 is formed in an annular shape so that, under the action of gravity, the inner peripheral surface thereof is far from or close to the attenuation portion 11 at an initial position where it abuts against the attenuation portion 11 when not vibrating. It is provided so as to be displaceably held by the attenuating portion 11 and is always urged so as to be able to return to the initial position by the action of gravity or upward force from the attenuating portion 11 when the attenuating portion 11 vibrates.
[0014]
And like each embodiment mentioned above, the vibration of the damping part 11 integrated with the damping object 13 becomes intense, and the vibration acceleration of the up-down direction of the damping part 11 becomes larger than 1G (G: gravity acceleration). When it comes, the mass body 12 separates from the attenuation part 11, jumps, and repeats collision with the attenuation part 11. As a result, the vibration energy of the vibration control object 13 is converted into the collision energy lost by the collision and the vibration energy of the mass body 12, and the vibration of the vibration control object 13 is suppressed.
The shape of the mass body 12 is not limited to an annular shape, and may be any shape (for example, an inverted U shape) that allows the mass body 12 to be stably supported on the attenuation portion 11 by the action of gravity. .
[0015]
FIG. 5 shows a vibration damping device 1D according to the fourth embodiment of the present invention, and portions common to the vibration damping device 1C shown in FIG.
In this vibration damping device 1 </ b> D, a flange portion 21 is provided at an end portion of the damping portion 11 projecting laterally from the vibration damping object 13, and the mass body 12 is interposed between this and the vibration damping object 13. The spring 22 is always urged and pressed toward the collar portion 21 by the interposed spring 22.
With such a configuration, the mass body 12 is stably held without being tilted, and the mass body 12 collides with the damping portion 11 in a constant state without wobbling. Can be obtained.
[0016]
FIG. 6 shows a vibration damping device 1E according to the fifth embodiment of the present invention, and portions common to the vibration damping device 1D shown in FIG.
In this vibration damping device 1E, the mass body 12 is formed by laminating a plurality of plate-like members 31 that can slide relative to each other. The plurality of plate-like members 31 slide in the same direction as the vibration direction of the mass body 12 (up and down direction in the drawing) (in the drawing, the left and right direction in the drawing). Are laminated in the direction of the axis of the attenuator 11.
With such a configuration, energy loss due to sliding friction between the plate-like members 31 is added, and the vibration damping action is further improved.
[0017]
FIG. 7 shows a screw compressor S0 to which the above-described vibration damping device 1C is applied, and parts that are common to the parts shown in FIGS. 4 and 11 are assigned the same reference numerals and description thereof is omitted.
In the screw compressor S0, the motor casing 52 corresponds to the above-described vibration suppression object 13.
A simulation result of the screw compressor S0 regarding the vibration of the motor casing 52 and the mass body 12 will be described below.
FIG. 8 (horizontal axis: time, vertical axis: displacement) shows the vibration state of the motor casing 52 when the vibration damping device 1C is not provided. As shown in the enlarged frame I, the motor casing 52 is shown in FIG. 52 has a substantially constant amplitude and vibrates at an extremely short period.
[0018]
On the other hand, FIG. 9 (horizontal axis: time, vertical axis: displacement) shows the vibration state of the motor casing 52 and the mass body 12 when the vibration damping device 1C is provided, and in the frame II in which the portion of time Δt is enlarged. As shown, the motor casing 52 vibrates at an extremely short cycle, and the mass body 12 vibrates at a slow cycle as compared with this. That is, in FIG. 9, the black portion represents the vibration state of the motor casing 52, and the curve group extending upward represents the vibration state of the mass body 12. Note that the upper part of the group of curves reaches a considerable height and is therefore omitted from the illustration. In FIG. 9, the mass body 12 collides with the motor casing 52, more precisely, the damping unit 11 with a period that is very slow compared to the vibration cycle of the damping unit 11, and the amplitude of the damping unit 11. It shows a state of jumping to a very large height compared to. Further, comparing FIG. 8 with FIG. 9, by providing the vibration damping device 1C, the amplitude of the motor casing 52 is remarkably reduced, and the vibration energy of the motor casing 52 is lost due to the collision with the mass body 12, And it is converted into the kinetic energy of the mass body 12, and it turns out that this conversion ratio is large.
[0019]
FIG. 10 shows the relationship between the motor rotation speed obtained from the simulation result and the amplitude of the motor casing 52 by a solid line III when the vibration damping device 1C is not provided, and a group when the mass body 12 is provided. This is indicated by point IV in FIG. In FIG. 10, a straight line V parallel to the horizontal axis indicates the amplitude of the motor casing 52 when the vibration acceleration of the damping unit 11 is 1G.
In FIG. 10, the vibration that starts to collide with the damping part 11 and the mass body 12 does not increase much from the vibration state when the vibration acceleration is 1 G, and the energy to be vibrated beyond this vibration state is almost attenuated. It shows that it is converted into energy accompanying the collision between the part 11 and the mass body 12.
[0020]
By the way, since the vibration damping device 1C, 1D, or 1E may cause a fretting phenomenon between the damping part 11 and the mass body 12 due to a collision between the damping unit 11 and the mass body 12 over a long period of use, avoid such a phenomenon as much as possible. As described above, it is preferable to fill a viscous substance such as grease between the attenuation portion 11 and the mass body 12.
Needless to say, the damping device 1A, 1B, 1D or 1E may be applied to the screw compressor S0 instead of the damping device 1C.
Further, the vibration direction of the vibration suppression target is not limited to the vertical direction, and may be a horizontal direction or a direction in which the vertical direction and the horizontal direction are combined.
[0021]
【The invention's effect】
As is apparent from the above description, according to the first invention, the compressor casing of the compressor body and the motor casing of the inverter motor are integrally coupled, and a pair of males and females that mesh with each other are contained in the compressor casing. A screw rotor is rotatably accommodated, and one of the rotor shafts is a vibration damping device provided in a compressor coupled to an output shaft in a motor casing, and the motor is arranged in substantially the same direction as the output shaft. A damping part that protrudes from the casing and is provided in the motor casing and vibrates integrally with the motor casing, and a position where the damping part is not vibrating is closer than a position where the damping part can collide with the damping part when the damping part vibrates. A mass body that is held displaceably so as to be far from or close to the attenuation portion at the initial position, and is always urged to return to the initial position. Provided, the damping portion is formed from rod-like body which projects in a direction perpendicular to the vibration direction in the motor casing, the mass body disposed between the end portion of the motor casing and the rod-like body The configuration is as follows.
For this reason, the vibration energy of the damping object is converted into the collision energy between the damping part and the mass body and the kinetic energy of the mass body, and the vibration of the damping object can be suppressed regardless of its natural frequency. Has the effect of becoming.
[0022]
In addition, since the vibration of the screw compressor is mainly caused by the drive motor, the vibration of the screw compressor is suppressed and the generation of noise based on this vibration is minimized regardless of the motor speed. There is an effect that it becomes possible.
[0023]
According to the second invention, in addition to the configuration of the first invention, the damping unit is provided with a flange portion overhanging from the upper Symbol rod-shaped body, a structure in which pressed always the flange portion by the mass body governance roots is there.
For this reason, there exists an effect that the effect by 1st invention can be acquired more stably.
[0024]
According to the third invention, in addition to the structure of any one of the first and second inventions, the mass body is formed by stacking a plurality of plate-like members that can slide relative to each other. .
For this reason, the vibration energy of the motor casing is also converted into the energy lost by the sliding friction between the plate-like members, and the effect of the first or second invention can be made more remarkable.
[Brief description of the drawings]
FIG. 1 is a front view of a vibration damping device according to a first embodiment of the present invention.
FIG. 2 is a side view of the vibration damping device shown in FIG.
FIG. 3 is a side view of a vibration damping device according to a second embodiment of the present invention.
FIG. 4 is a partial cross-sectional front view of a vibration damping device according to a third embodiment of the present invention.
FIG. 5 is a partial cross-sectional front view of a vibration damping device according to a fourth embodiment of the present invention.
FIG. 6 is a partial sectional front view of a vibration damping device according to a fifth embodiment of the present invention.
FIG. 7 is a partial cross-sectional front view of a screw compressor to which a vibration damping device according to a third embodiment of the present invention is applied.
8 is a diagram showing a vibration state in the case where a vibration damping device is not provided as a result of simulation regarding vibration of the screw compressor shown in FIG. 7; FIG.
9 is a diagram showing a vibration state in the case where a vibration damping device is provided as a result of simulation regarding vibration of the screw compressor shown in FIG. 7; FIG.
FIG. 10 is a diagram showing the relationship between the motor rotation speed and the compressor amplitude, as a result of simulation regarding the vibration of the screw compressor shown in FIG. 7;
FIG. 11 is a front view of a conventional screw compressor.
FIG. 12 is a front view of another conventional screw compressor.
13 is a diagram showing vibration characteristics of the screw compressor shown in FIG.
14 is a diagram showing vibration characteristics of the screw compressor shown in FIG. 12. FIG.
[Explanation of symbols]
1A to 1E Damping device 11 Damping part 12 Mass body 13 Damping object 14 Spring 15 Stationary part 21 Collar part 22 Spring 31 Plate member 51 Compressor casing 52 Motor casing 53 Anti-vibration rubber 54 Base plate C Compressor body M Motor S0 screw compressor

Claims (3)

The compressor casing of the compressor body and the motor casing of the inverter motor are integrally coupled, and a pair of male and female screw rotors that mesh with each other are rotatably accommodated in the compressor casing, and one of the rotors A damping device provided in a compressor whose shaft is coupled to an output shaft in a motor casing,
A damping part that protrudes from the motor casing in substantially the same direction as the output shaft, is provided in the motor casing, and vibrates integrally with the motor casing;
At an initial position that is closer to the non-vibrating position of the damping part than a position where it can collide with the damping part during vibration, it is held displaceably so as to be far from or close to the damping part, and A mass body constantly biased so as to return to the initial position ,
The attenuating portion is formed of a rod-like body projecting on the motor casing in a direction orthogonal to the vibration direction, and the mass body is disposed between the motor casing and the end of the rod-like body. A vibration damping device characterized by that. The damping unit is provided with a flange portion overhanging from the upper Symbol rod body vibration damping apparatus according to claim 1, characterized in that pressed against the always the flange portion by the mass governor roots.   3. The vibration damping device according to claim 1, wherein the mass body is formed by stacking a plurality of plate-like members that can slide relative to each other.

Images