JP2849973B2 - Anti-vibration structure of local oscillator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local oscillator for suppressing phase noise in, for example, a satellite communication device mounted on an aircraft, and more particularly, to a vibration isolation structure thereof.

[0002]

2. Description of the Related Art Conventionally, a vibration isolating structure of a local oscillator of this kind has been used in a satellite communication apparatus for the purpose of countermeasures against phase noise due to mechanical vibration.

FIG. 6 is an exploded perspective view showing a conventional anti-vibration structure of a local oscillator, and FIG. 7 is a sectional view taken along line AA of FIG. The local oscillator main body 1 generates phase noise due to weak mechanical vibration. The main body 1 is inserted into the case 7 with the vibration-proof rubber 6 attached to each corner, and the upper surface is further covered by the cover 8.

The vibration isolating rubber 6 is for suppressing external mechanical vibration. The case 7 is for fixing the side and bottom surfaces of the local oscillator main body 1 supported by the anti-vibration rubber 6 via the anti-vibration rubber 6. Cover 8
Is for fixing the upper surface of the local oscillator main body 1 via the vibration isolating rubber 6.

Japanese Patent Application Laid-Open No. 57-72253 (hereinafter abbreviated as Prior Art 1) discloses that two kinds of disks are alternately arranged on a fixed shaft side for supporting a rotating shaft of a rotating anode type X-ray tube. There is disclosed a rotating anode structure of an X-ray tube provided with a friction damper having a stacked structure or a structure in which multiple cylinders are stacked.

Further, Japanese Patent Application Laid-Open No. 61-223508 (hereinafter abbreviated as Prior Art 2) discloses that a vibration isolating rubber, a damper and a spring are provided between a detector for detecting radiation intensity and a frame piece. A radiolucent thickness gauge with a buffer interposed is disclosed.

[0007]

However, in the conventional vibration isolating structure shown in FIGS. 6 and 7, since the elastic force of rubber is used as a vibration isolating material, for example, the resonance frequency of an aircraft is 68 [Hz]. In order to reduce the resonance frequency of the vibration isolating structure to 30 [Hz] or less, the weight of the local oscillator body 1 is equivalent to 1 [kg]. Therefore, there is a problem in terms of weight when it is used for an on-board communication device that needs to be reduced in weight.

Further, when rubber is used as the vibration-proof material, the response at the time of resonance can be suppressed to about 2.4 times, but the vibration-proof effect near the resonance frequency 68 [Hz] of the aircraft has a response magnification of 0. Approximately three times. Therefore, there remains a problem that it is insufficient as a countermeasure against the phase noise of the local oscillator.

Further, when the friction damper or the shock absorber disclosed in the prior arts 1 and 2 is diverted as the vibration isolating structure, there is still a problem in weight.

As described above, the conventional anti-vibration structure of a local oscillator has a problem in weight when used in, for example, a communication device mounted on an aircraft, and the anti-vibration effect as a measure against phase noise is insufficient. Met.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is light in weight, can sufficiently suppress the response at the time of resonance, and can effectively exhibit an anti-vibration effect, and is particularly used for a communication device mounted on an aircraft. It is an object of the present invention to provide an anti-vibration structure for a local oscillator which is extremely useful in such a case.

[0012]

According to the present invention, in the vibration damping structure for an oscillator, the main body of the oscillator is suspended on the upper and lower blankets via a coil spring, and the main body of the oscillator is connected to at least the upper and lower parts. A vibration damping structure for an oscillator can be obtained, wherein a viscoelastic attenuator is interposed between one of the brackets.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. 1 and 2, the same parts as those in FIGS. 6 and 7 are denoted by the same reference numerals, and different parts will be mainly described here.

FIG. 1 is an exploded perspective view showing a vibration isolating structure of a local oscillator according to the present invention, and FIG. 2 is a sectional view taken along line AA of FIG.

As shown in FIG. 1, the local oscillator main body 1 is supported by four coil springs 2 each vertically and one viscoelastic attenuator 3 suspended vertically by brackets 4 and 5, respectively. ing. Therefore, the transmission path of the mechanical vibration to the local oscillator main body 1 is only the coil spring 2 and the viscoelastic attenuator 3.

The resonance frequency according to this configuration can be arbitrarily set by changing the length and type of the coil spring 2 as shown in FIG. Also, by changing the viscosity and compressibility of the viscoelastic body of the viscoelastic attenuator 3, it is possible to set an arbitrary resonance frequency.

Incidentally, in the embodiment shown in FIG.
Are constituted by a combination of four upper and lower and two viscoelastic attenuators 3 respectively, but the present invention is not limited to this. For example, depending on the type of mechanical vibration, it is also possible to realize an appropriate vibration damping effect by increasing or decreasing the number of coil springs 2 and increasing or decreasing the number of viscoelastic dampers 3.

According to the above configuration, since the coil spring 2 is used as a vibration isolator, the resonance frequency 3
The frequency can be set to 0 [Hz] or less, and an anti-vibration effect can be obtained in a wider frequency range. Further, by adding the viscoelastic attenuator 3, it is possible to suppress the response at the time of resonance while minimizing the influence on the vibration isolation effect.

3 to 5 are exploded perspective views showing other embodiments according to the present invention.

The structure shown in FIG. 3 is an anti-vibration structure in which the coil spring 2 supports only four upper and lower coils. The structure shown in FIG. 4 is an anti-vibration structure in which four upper and lower coil springs 2 and one lower viscoelastic attenuator 3 are combined. The structure shown in FIG. 5 is an anti-vibration structure in which the viscoelastic attenuator 3 supports only one upper and lower member.

In any of the embodiments, an arbitrary resonance frequency can be set by the method described above. For example,
Assuming a case where the present invention is used for a communication device mounted on an aircraft, it is possible to easily realize that the resonance frequency of the local oscillator body 1 is suppressed to 30 [Hz] or less with respect to the resonance frequency 68 [Hz] of the aircraft.

The coil spring 2 and the viscoelastic damper 3
Are extremely lighter in weight than anti-vibration rubbers, and can be reduced to a sufficiently satisfactory level for use in aircraft.

It goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0024]

As described above, according to the present invention, it is possible to effectively exhibit a vibration damping effect by being light in weight and sufficiently suppressing a response at the time of resonance. An extremely useful vibration damping structure for a local oscillator can be provided.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an anti-vibration structure of a local oscillator according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an exploded perspective view showing an anti-vibration structure according to another embodiment of the present invention in which only four upper and lower coil springs are supported.

FIG. 4 is an exploded perspective view showing an anti-vibration structure of a combination of four upper and lower coil springs and one lower viscoelastic attenuator as another embodiment according to the present invention.

FIG. 5 is an exploded perspective view showing, as another embodiment according to the present invention, a vibration isolating structure in which a viscoelastic attenuator is supported by only one upper and lower member.

FIG. 6 is an exploded perspective view showing a conventional vibration isolating structure of a local oscillator.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Local oscillator body 2 Coil spring 3 Viscoelastic attenuator 4 Upper bracket 5 Lower bracket 6 Anti-vibration rubber 7 Case 8 Cover

Continuation of the front page (56) References JP-A 52-99709 (JP, U) JP-A 3-69336 (JP, U) JP-A 4-68593 (JP, U) (58) Fields surveyed (Int) .Cl. ⁶ , DB name) H05K 7/12 H03B 1/00

Claims (1)

(57) [Claims] In a vibration isolating structure for an oscillator, a main body of the oscillator is suspended on upper and lower blankets via a coil spring, and a viscosity is provided between the main body of the oscillator and at least one of upper and lower brackets. An anti-vibration structure for an oscillator, wherein an elastic attenuator is interposed.