JPH061097B2 - Dynamic vibration absorber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dynamic vibration reducer. More specifically, the present invention relates to a phase control type dynamic vibration reducer for reducing vibration of a vibrating body.

[Prior Art] Conventionally, when damping vibration of a vibrating body, a dynamic vibration reducer is used, and a preset natural frequency of the dynamic vibration reducer is referred to as a frequency of the vibrating body by an external forcing force F (hereinafter referred to as vibration frequency f). The same vibration is absorbed by the vibration body. However, in a mass-produced vibrating body, for example, in an automobile, there are variations in component parts, which causes variations in the natural frequency f ₁ of the vibrating body between vehicles, and further in the dynamic vibration absorber itself due to variations in parts constituting the dynamic vibration absorber. As a result, there is a variation in the natural frequency of.

Therefore, it is very difficult to make the natural frequency of the dynamic vibration absorber equal to the vibration frequency f of the vibrating body to be absorbed. Therefore, although the vibration absorbing effect at the natural frequency of the dynamic vibration absorber is obtained, when it is deviated from the aimed vibration frequency f,
The dynamic vibration reducer and the vibrating body resonate, causing a problem that the vibrating body vibrates rather greatly at the vibration frequency f to be originally absorbed.

Further, in such a conventional dynamic vibration absorber, since the vibration absorbing effect is obtained only at the vibration frequency f of the vibrating body that is the same as the preset natural frequency of the dynamic vibration absorber, for example, the vibration frequency f of the vibrating body is In an environment where changes, the number of dynamic vibration absorbers must be provided as many as the vibration frequency f to be absorbed,
It is very uneconomical and there is a problem that the number of superpositions increases more than necessary.

Here, in order to solve such a problem, the vibration frequency f of the vibrating body is detected, and the main part of the dynamic vibration reducer is mechanically or electrically changed to change the spring constant of the dynamic vibration reducer vibration system. A dynamic vibration reducer has been provided in which the natural frequency f ₀ of the dynamic vibration reducer is synchronized with the vibration frequency f of the vibrating body.

However, even in this dynamic vibration absorber, due to variations in the components of the dynamic vibration absorber, it is not possible to obtain an appropriate spring constant of the dynamic vibration absorber vibration system even if the main part of the dynamic vibration absorber is changed. is there.

Above all, since it is necessary to accurately detect the vibration frequency f to be damped in the above-described dynamic vibration reducer, for example, the vibration frequency f of the vibrating body is changed due to a change in the engine speed of the vehicle such as in an automobile. In an environment in which the frequency changes in a complicated manner, it is necessary to provide a complicated frequency detection circuit. Further, even if the vibration frequency f can be accurately detected, the spring constant of the dynamic vibration absorber vibration system is changed after the vibration frequency f is changed. Could not be changed, and a sufficient vibration absorbing effect could not be obtained.

SUMMARY OF THE INVENTION Therefore, the present invention provides a dynamic vibration absorber that can efficiently absorb the vibration of a vibrating body by following the complicatedly changing vibration frequency f without providing a complicated frequency detection circuit. The purpose is to do.

[Configuration of the Invention] A configuration of the present invention for achieving the above object is a dynamic vibration reducer that is fixed to a vibration body and absorbs the vibration of the vibration body to reduce the vibration of the vibration body. An arm portion for connecting a weight body provided outside the dynamic vibration absorber body, an arm portion varying means for changing a length of a portion of the arm portion that can vibrate with respect to the dynamic vibration absorber body, and the vibrating body A vibrating body acceleration detecting means for detecting an acceleration of the vibrating body and outputting a vibrating body acceleration signal; a vibrating body acceleration detecting means for detecting an acceleration of the weight body and outputting a weight body acceleration signal; A control signal to the arm variable means so that the phase difference between the phase of the vibration acceleration of the vibrator detected based on the acceleration signal of the weight and the phase of the vibration acceleration of the weight detected based on the acceleration signal of the weight falls within a predetermined range. And a dynamic control means for controlling the output. The main point is a shaker.

[Operation and Effect of the Invention] In the dynamic vibration absorber of the present invention configured as described above,
The vibrating body acceleration detecting means detects the acceleration of the vibrating body and outputs a vibrating body acceleration signal. Further, the weight body acceleration detecting means detects the acceleration of the weight body and outputs a weight body acceleration signal. Then, the control means detects the phase of the vibration acceleration of the vibration body and the phase of the vibration acceleration of the weight body from the vibration body acceleration signal and the weight body acceleration signal, respectively, and the phase difference between these is always detected. A control signal is output to the arm variable means so that the range is within a predetermined range. Then, the arm portion changing means is based on the control signal, the arm portion connecting the dynamic vibration absorber main body and the weight body provided outside the dynamic vibration absorber main body to the dynamic vibration absorber main body. Change the length of the vibrating part.

That is, in the dynamic vibration absorber of the present invention, the phase difference between the phase of the vibration acceleration of the vibrating body and the phase of the vibration acceleration of the weight body,
The vibration system spring constant of the dynamic vibration reducer is changed by changing the length of the portion of the arm that can vibrate with respect to the main body of the dynamic vibration reducer so that it is always within the predetermined range.

As will be described later, if the phase difference between the phase of the vibration acceleration of the vibrating body and the phase of the vibration acceleration of the weight body is controlled within a predetermined range (preferably 70 ° to 90 °), the This is because the natural frequency f ₀ of the dynamic vibration absorber can be matched with the vibration frequency f of the vibrating body, and the amplitude of the vibrating body can be reliably reduced in the vicinity thereof.

Therefore, in the dynamic vibration absorber of the present invention, a sufficient vibration absorption effect can be obtained without providing a complicated frequency detection circuit. Further, this vibration absorbing effect is not affected by manufacturing variations of the components forming the vibrating body and the dynamic vibration reducer itself.

Furthermore, the dynamic vibration reducer of the present invention does not change the spring constant of the dynamic vibration reducer vibration system after the vibration frequency f changes, unlike the conventional dynamic vibration reducer that detects only the vibration frequency f of the vibration body. , To control the spring constant based on the phase difference,
For example, even in an environment where the vibration frequency f of the vibrating body changes intricately due to changes in the engine speed and vehicle speed, such as in an automobile, the vibration of the vibrating body is absorbed in the process of changing the vibration frequency f. can do.

That is, a sufficient vibration absorbing effect is obtained by following the vibration frequency f that changes in a complicated manner, and it is not necessary to provide dynamic vibration absorbers by the number of the vibration frequencies f to be absorbed.

[Examples] Hereinafter, the present invention will be described with reference to the drawings with reference to Examples.
FIG. 1 shows a first embodiment of the present invention, which is a phase control type dynamic vibration absorber for an automobile.

1 is a dynamic vibration absorber case, 2a and 2b are shaft holes formed in the dynamic vibration absorber case 1, 3a and 3b are bearings provided in the shaft hole, and 4a and 4b are holes in the dynamic vibration absorber case 1. The fixed holes 5 for mounting the dynamic vibration absorber are designated by 5 and the motor is arranged in the dynamic vibration absorber case 1, and 6 is a pinion gear directly connected to the motor 5. The arm 5 is constituted by the motor 5 and the pinion gear 6, and the dynamic vibration absorber main body is constituted by the dynamic vibration absorber case 1, the shaft holes 2a and 2b, the bearings 3a and 3b, the fixing holes 4a and 4b, the motor 5 and the pinion gear 6. Bolts 7a, 7 inserted into the fixing holes 4a, 4b
It is attached to the vibrating body 8 at b.

Specific examples of the vibrating body 8 include various devices such as an engine, a steering column, an exhaust pipe, a seat, a vehicle frame, and a suspension.

Reference numeral 9 is a weight body made of metal or the like and having a mass adjusted appropriately,
Reference numeral 10 denotes a position variable lever fixed to the weight body 9 and corresponding to the arm portion. Further, the position variable lever 10 is provided with a rack 11 at a predetermined position. The position variable lever 10 is inserted into the shaft holes 2a and 2b, and the rack 11 is meshed with the pinion gear 6. As a result, when the motor 5 is driven and the pinion gear 6 rotates, the weight body 9 reciprocates in the horizontal direction in the figure due to the displacement of the position variable lever 10, and the dynamic vibration absorption of the position variable lever 10 as an arm portion. The effective length l that can vibrate with respect to the dynamic vibration absorber case 1 as the main body of the device changes.

Reference numeral 12 denotes a vibrating body acceleration sensor corresponding to the vibrating body acceleration detecting means, which detects a vibrating acceleration of the vibrating body 8 and outputs a vibrating body acceleration signal. The vibrating body acceleration sensor 12 is fixed to a predetermined surface of the dynamic vibration absorber case 1.

Reference numeral 13 denotes a weight acceleration sensor which corresponds to weight acceleration detecting means, which detects the vibration acceleration of the weight 9 and outputs a weight acceleration signal. The weight acceleration sensor 13 is fixed to a predetermined surface of the weight 9.

The vibration body acceleration sensor 12 and the weight body acceleration sensor 13
Is fixed to detect acceleration in the same direction.

Next, FIG. 2 shows a model of a vibration system including a vibration body and a dynamic vibration reducer.

A case where the external force F is applied to the vibrating body 8 will be described.

The spring constant of the vibrator 8 is k ₁ , the damping constant is c ₁ , and the mass is m.
₁ , the amplitude is x ₁ , the spring constant of the dynamic vibration absorber is k ₂ , the damping constant is c ₂ , the mass of the weight body is m ₁ , and the amplitude is x ₂ , in the case of only spring constants k ₁ and k ₂ , The differential equation of the vibration system is equation (1).

The formula (1) is transformed into the formula (2).

When the terms of the damping constants c ₁ and c ₂ are further added to the equation (2), the following equation (3) is obtained.

Here, the angular frequency of the vibrating body 8 due to the external forcing force F is ω, F ₀ , x ₁₀ and x ₂₀ are proportional constants, and Ψ ₁ is the vibrating body 8
The phase of the vibration acceleration (hereinafter simply referred to as the phase Ψ ₁ ), Ψ
As ₂ dynamic absorber of vibration acceleration phase (hereinafter simply referred to as phase [psi _{2), F,} putting x 1, _{x 2} and as respectively (4), the _{x 1} and _{x 2,} respectively at time t The first-order derivative and the second-order derivative are as shown in equations (5) and (6).

Next, substituting equations (4), (5), and (6) into equation (3) yields equation (7).

Here, if A = k ₁ k ₂ −m ₁ ω ² + j (c ₁ + c ₂ ) ω, B = −k ₂ −jc ₂ ω, C = k ₂ −m ₂ ω ² + jc ₂ ω, then ( The equation (7) becomes a determinant like the equation (8) when t = O.

Then, solving equation (8) yields equation (9).

Then, the expression (10) is derived from the expression (9).

Here, the natural frequency of the dynamic vibration absorber is ω ₀ , Then, the equation (11) is obtained from the equation (10).

Therefore, when the phase difference between the phase Ψ ₁ and the phase Ψ ₂ is φ (hereinafter simply referred to as the phase difference φ), the phase difference φ at the natural frequency f ₀ of the dynamic vibration absorber is tenφ = k ₂ / c ₂ ω (12 ). At this time, the phase difference takes a value in the vicinity of 70 ° to 90 ° within the range of the general damping constant.

That is, FIG. 3 shows the relationship between the vibration frequency f of the vibrating body due to the external forcing force F and the phase difference φ. The phase difference φ becomes a value near 90 ° near the natural frequency f ₀ . The relationship between the vibration frequency f before and after the dynamic vibration reducer is attached and the amplitude x ₁ of the vibrating body (hereinafter referred to as the vibration absorption characteristic) is as shown in the graph in FIG. 4. The dotted line is before the dynamic vibration reducer is attached, and the solid line is the natural frequency f. The relationship after the dynamic vibration reducer is attached near ₀ is shown.

That is, after the dynamic vibration reducer is attached, the amplitude x ₁ near the natural frequency f ₀
Is decreasing. Thus, the phase difference φ is 70 ° to 90 °
Then, it can be seen that the vibration is efficiently absorbed. Therefore, the dynamic vibration absorber may be controlled so that the phase difference φ is 70 ° to 90 °.

The case where the phase difference is 90 ° will be described below.
When k, c, and ω are determined, accurate control is possible by detecting the phase with the value (φ) as a reference.

In order to achieve the vibration reduction based on the above theory, in this embodiment, the feedback circuit 14 corresponding to the control means is constructed as shown in FIG. The configuration and operation of the feedback circuit 14 will be described below.

Reference numeral 21 denotes an input terminal for inputting a weight acceleration signal, and 22 denotes an input terminal for inputting a vibration acceleration signal. Reference numeral 23 is an angular frequency sensor that obtains an output voltage Vω that is proportional to the angular frequency of the external force F (for example, engine speed). The reason why the sensor is provided is that, in the present embodiment, the vibrating body is made up of various parts such as the engine, the propeller shaft, and the wheels, so that, for example, even when it is desired to mainly absorb the vibration caused by the rotation of the engine. , Vibrations from various parts such as wheels are combined, and a signal of a complicated distorted wave composed of a fundamental wave and a high frequency is fed back from the vibrator acceleration sensor 12 to the feedback circuit 1.
It is because it enters 4. Therefore, in this embodiment,
Each frequency sensor 23 is provided in order to extract only the vibration acceleration in the frequency band of the vibration caused by the vibration source (for example, engine) to be absorbed from the vibration frequencies caused by the plurality of vibration sources. The frequency of the engine desired to be detected is detected, and the filtering frequencies of the tracking filters 24 and 25 are changed based on the frequency signal.

Reference numerals 24 and 25 denote tracking filters for passing only the frequency component corresponding to the output of the angular frequency sensor 23 among the frequency components of the outputs obtained from the weight acceleration sensor 13 and the vibration acceleration sensor 12, respectively. Reference numeral 26 is a phase shifter that advances the phase of the output of the tracking filter 24 by 90 °. Reference numeral 27 is a phase difference detector for obtaining an output signal proportional to the phase difference between the outputs of the tracking filter 25 and the phase shifter 26. The phase difference detector 27 will be described below.

Reference numerals 28 and 29 denote polarity discriminators configured to obtain a positive constant voltage when the output signals of the phase shifter 26 and the tracking filter 25 have a positive polarity, and a negative constant voltage when the output signals have a negative polarity, and 30 denotes a polarity discriminator. A diode for rectifying an output from the device 28, a diode 31 for rectifying an output from the polarity discriminator 29, and a signal 32 from the diodes 30 and 31 as input R and input V are proportional to the phase difference between the inputs R and V. And a phase comparator that outputs a signal corresponding thereto. As the phase comparator 32, for example, as shown in FIG. 6, a well-known circuit composed of a plurality of NAND gates can be cited. In the same circuit, when the rising phases are the same, the two outputs U and D become high level, and the input When the phase of R is advanced with respect to the input V, the output U becomes low level for the time corresponding to the phase difference. Conversely, when the phase of the input R is delayed with respect to the input V, the phase difference is generated. The output D is set to the low level only for the time corresponding to. Reference numeral 33 is a phase inverter for inverting the output U, 34 is a phase inverter for inverting the output D, and 35 is a linear differential for discriminating the outputs from the inverters 33, 34 and outputting a DC voltage proportional to the outputs. It is an amplifier. The phase difference detector 27 is configured as described above.

Reference numeral 36 denotes a motor drive circuit which inputs the DC voltage from the detector 27 and outputs a drive signal to the motor 5.

With the feedback circuit 14 configured in this way, when the phase difference φ is not 90 °, the motor is driven until the phase difference φ becomes 90 ° based on the DC voltage proportional to the phase difference φ, and the weight 9 is used. , The position variable lever 10 is reciprocated, and as a result,
The spring constants k ₂ and c ₂ of the dynamic vibration reducer are changed. When the phase difference φ becomes 90 °, the motor 5, the weight body 9, and the position variable lever 10 are stopped. That is, the vibrating system including the vibrating body and the dynamic vibration absorber is always constructed so that the phase difference φ between the vibrations of both is 90 °.

FIG. 7 shows changes in the output of each element of the feedback circuit 14 when signals of various phase differences are input to the feedback circuit 14. In the figure, (a) shows the case where the phase ψ ₁ is delayed by 90 ° from the phase ψ ₂ , and (b) shows the case where the phase ψ ₁ and the phase ψ ₂ are the same phase.
(C) shows the case where the phase ψ ₁ leads the phase ψ ₂ by 45 °, and (d) shows the case where the phase ψ ₁ leads the phase ψ ₂ by 135 °. 21in is an input from the weight body acceleration sensor 13 of the weight body 9, 22in is an input from the vibrating body acceleration sensor 12, 26out is an output of the phase shifter, 30Rout is an output R of the diode 30, and 31Vout.
Is the output V of the diode 31, and 32Uout is the phase comparator 3
2 output U, 32Dout is the output D of the phase comparator 32, 3
3out is the output of the phase comparator 33, 34out is the phase comparator 3
4 and 35 out represent the output of the linear differential amplifier 35, respectively.

It should be noted that, in addition to the feedback circuit 14 described above, a similar circuit is provided as an eighth circuit.
Feedback circuit 41 incorporating the phase difference detector 40 as shown in the figure
Is mentioned. This feedback circuit 41 is the feedback circuit 14 described above.
The NAND gate 42, the integrator 43, and the RS flip-flop 44 are incorporated in place of the linear differential amplifier 35 in FIG. The integrator 43 that outputs a voltage proportional to the phase difference
And an RS flip-flop 44 for instructing the rotating direction of the motor 5 and the moving direction of the position variable lever 10 by binary output.
Both signals are output to the motor drive circuit 45.

With the dynamic vibration reducer of the present embodiment described above, the frequency band caused by a desired vibration source (for example, an engine) detected from the vibration frequencies caused by a plurality of vibration sources with the aid of the angular frequency sensor 23 described above. The vibration of b is represented by the vibration absorption characteristics shown in FIG. 9 (in the case of the low frequency region), FIG. 10 (in the case of the intermediate frequency region) and FIG. 11 (in the case of the high frequency region). The vibration of the vibrating body is efficiently absorbed.

Further, as shown in FIG. 12, also in a vibrating body (hereinafter referred to as a vibrating body having a rigidity characteristic) whose amplitude x ₁ does not change so much with respect to the change of the vibrating frequency f, the feedback circuit is operated to set the phase difference φ to 90. By setting it as °, only the vibration of the target frequency can be absorbed.

Next, a second embodiment of the present invention as shown in FIG. 13 will be described. Reference numeral 61 is a dynamic vibration absorber case. Reference numeral 62 is a shaft hole formed in the dynamic vibration absorber case 1. A female screw 63 is cut on the inner circumference of the hole 62. Reference numerals 64a and 64b are fixing holes formed in the dynamic vibration absorber case 1 for mounting the dynamic vibration absorber. A motor 65 is provided inside the dynamic vibration absorber case 61, and a pinion gear 66 is directly connected to the motor 65. Further, the dynamic vibration absorber main body is made up of the dynamic vibration absorber case 61,
The shaft hole 62, the fixing holes 64a and 64b, the motor 65, and the pinion gear 66 are included in the fixing holes 64a and 64b. It is attached to the vibrating body 68 with bolts 67a and 67b.

Reference numeral 69 is a weight body whose mass is appropriately adjusted, and 70 is an arm portion, and is a hollow cylindrical weight body connecting portion made of an elastic material such as rubber. As shown in FIG. 13, the body connecting portion 70 is configured to connect the weight body 69 and the dynamic vibration absorber main body, and the shaft hole 62 and the hollow portion of the weight connecting portion 70 are communicated with each other.

Reference numeral 71 denotes a bolt-shaped rod having a round head 71b provided with a gear 71a at the lower end, and a male screw is cut on the outer periphery of the rod 71, and the rod 71 is fitted in the hollow portion of the weight body connecting portion 70 to form a female screw in the shaft hole 62. It is screwed with 63. The pinion gear 66 is meshed with the gear 71a. When the motor 65 is driven, the pinion gear 66 is rotated, and further, the pinion gear 66 rotates the gear 71a to reciprocate up and down depending on the rotating direction. In response to this, the effective length l of the weight body connecting portion 70 as the arm portion that can vibrate with respect to the dynamic vibration absorber case 61 as the dynamic vibration absorber body changes.

The motor 65, the pinion gear 66, the rod 71, and the gear 71a constitute an arm changing means. Reference numeral 72 denotes a vibrating body acceleration sensor corresponding to vibrating body acceleration detecting means, which detects the vibrating acceleration of the vibrating body 68 and outputs a vibrating body acceleration signal. The vibrator acceleration sensor 72 is the vibration absorber case 61.
Fixed on a predetermined surface of the.

Reference numeral 73 denotes a weight body acceleration sensor corresponding to weight body acceleration detecting means, which detects a vibration acceleration of the weight body 69 and outputs a weight body acceleration signal. The weight acceleration sensor 73 is the weight 6
9 is fixed on a predetermined surface.

The feedback circuit 74 corresponding to the control means has the same structure and operation as the feedback circuit 14 of the first embodiment.

In the second embodiment configured as described above, the phases ψ ₁ and ψ ₂ are detected by the sensors 72 and 73, and the phase difference φ is always 90 °.
The feedback circuit 74 operates to control the
Is restricted by the rod 71 and vibrates, that is, the effective length l of the arm changes, so that the spring constant of the dynamic vibration reducer changes. Therefore, the natural frequency f linked to the vibration frequency
Near ₀ , the vibration absorbing effect of the dynamic vibration absorber becomes maximum.

As described above, in both the first and second embodiments, the dynamic vibration absorber main body of the arm portion is maintained so that the phase difference between the phase ψ _{1 of the} vibrating body and the phase ψ _{2 of the} weight body is always maintained at 90 °. On the other hand, the length of the vibrating portion is controlled to change the spring constant k ₂ of the dynamic vibration reducer.

Therefore, even if the natural frequency of each of the components of the vibrating body or the dynamic vibration absorber varies, the vibration of the desired frequency can be absorbed regardless of the variation.

In addition, even if the vibration frequency of the vibration source of the vibrating body changes, the vibration can be absorbed by following it, so it is not necessary to use many dynamic vibration absorbers in accordance with the vibration frequency, and you want to always absorb the vibration of the vibrating body at the desired frequency. Can be efficiently absorbed.

In both the first and second embodiments, the feedback circuit may be a microcomputer and the phase difference φ is 70 ° to 90 °.
It may be in the range of °, and neither is limited to this embodiment.

Further, in both the first and second embodiments, the angular frequency sensor 23 and the tracking filter 24, in order to damp only the vibration caused by the engine from the vibrations caused by the plurality of vibration sources, 25 is additionally provided, for example, when the vibration source of the vibrating body is single, or the vibration frequency caused by the vibration source desired to be absorbed is not so much influenced by the vibration frequencies caused by other vibration sources. In such a case, the output signal of the weight acceleration sensor 13 is directly input to the phase shifter 26, and the output signal of the vibration acceleration sensor 12 is directly input to the polarity discriminator 29 in the phase difference detectors 27 and 40. Even if the input signal is input to, the vibration can be reliably absorbed regardless of variations in the components of the vibrating body and the dynamic vibration absorber, and even when the vibration frequency of the vibrating body changes intricately.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention, FIG. 2 is a schematic diagram showing a model of a vibration system including a vibration body and a dynamic vibration absorber, and FIG.
FIG. 4 is a graph showing the relationship between the vibration frequency f and the phase difference φ, FIG. 4 is a graph showing the vibration absorption characteristics, FIG. 5 is a block diagram of the feedback circuit of the first embodiment, and FIG. 6 is an example of a phase comparator. 7 is a timing chart of signals in a feedback circuit at various phase differences, FIG. 8 is a block diagram of another feedback circuit of the first embodiment, and FIG. 9 is a vibration absorption characteristic in a low frequency region. FIG. 10 is a graph showing vibration absorbing characteristics in the intermediate frequency region, FIG. 11 is a graph showing vibration absorbing characteristics in the high frequency region, FIG. 12 is a vibration absorbing characteristic of a vibrating body having a rigid characteristic, and FIG. The block diagram of an Example is shown. 8, 68 ... Vibration body 9, 69 ... Weight body 10 ... Position variable lever 12, 72 ... Vibration body acceleration sensor 13, 73 ... Weight body acceleration sensor 24, 25 ... Tracking filter 28, 29 ... Polarity discriminator 30, 31 ... Diode 32 ... Phase comparator 71 ... Rod

Claims (1)

[Claims] 1. A dynamic vibration reducer fixed to a vibration body to absorb the vibration of the vibration body and reduce the vibration of the vibration body, comprising: a dynamic vibration absorber main body; and a weight body provided outside the dynamic vibration absorber main body. An arm portion to be connected, an arm portion varying means for changing a length of a portion of the arm portion which can vibrate with respect to the dynamic vibration absorber body, and an acceleration of the vibrating body is detected to output a vibrating body acceleration signal. Vibration body acceleration detection means, weight body acceleration detection means for detecting acceleration of the weight body and outputting a weight body acceleration signal, and phase of vibration acceleration of the vibration body detected based on the vibration body acceleration signal, and Control means for outputting a control signal to the arm variable means so that the phase difference from the phase of the vibration acceleration of the weight body detected based on the weight body acceleration signal is within a predetermined range. A dynamic vibration absorber.