JP2002158513A - Dielectric resonator device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce component costs and to shorten time for controlling resonance frequency using a frequency control screw. SOLUTION: A dielectric resonator system 1 is configured by providing a screw hole 3 on the upper surface of a conductive shield 2, which covers a dielectric resonator 5, and fastening a frequency control screw 4 into the screw hole 3. A screw head equally forming a pressure side flank angle, and idle side flank angle is engraved around all the periphery of the frequency control screw 4 and on the top of the screw head, a groove is provided along with that screw head top.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric resonator device, and more particularly, to a dielectric resonator device having a dielectric resonator whose resonance frequency can be adjusted by a screw.

[0002]

2. Description of the Related Art A conventional dielectric resonator device whose resonance frequency can be adjusted by a screw (hereinafter referred to as a conventional dielectric resonator device) is described in, for example, Japanese Utility Model Publication No. 7-1847. There is something. This dielectric resonator device adjusts the resonance frequency by changing the distance between the adjustment screw and the upper surface of the dielectric resonator installed in the metal shield by turning the adjustment screw. Using a tapping screw, screw into the screw hole provided on the upper surface of the metal shield body while cutting the screw groove, eliminating the tapping of the screw hole, suppressing rattling and facilitating frequency adjustment. I have. A dielectric material that is screwed into a screw hole using a resin-processed screw having a resin (for example, epoxy or the like) adhered to the screw portion, to eliminate rattling due to friction between the resin and the screw hole, and to adjust a resonance frequency. 2. Description of the Related Art A resonator device and a dielectric resonator device that adjusts a resonance frequency by attaching an adjustment screw and a lock nut in combination to adjust a resonance frequency are known as conventional dielectric resonator devices.

[0003]

However, in these conventional dielectric resonator devices, when a tapping screw is used as an adjusting screw, once the screw is turned in the pulling-out direction, the engagement between the female screw and the male screw is loosened. Since the holding force is deteriorated, the adjustment screw and the screw hole are finally attached with an adhesive and the like, and the extra work is required to fix the two and suppress the rattling, and the adjustment time is long. In addition, when metal chips from the tapping screw when the metal chips fall into the metal shield body, an electrical short circuit may be caused, which may lead to a failure of the device. Also,
In the case of using a resin-processed screw as the adjusting screw, the component cost is increased. When a lock nut is used, an increase in the cost of the lock nut in addition to the adjustment screw is unavoidable, and furthermore, the resonance frequency adjustment requires two-step adjustment with the adjustment screw and the lock nut. The adjustment took a long time.

[0004] In view of these problems, an object of the present invention is to provide a dielectric resonator device that reduces the cost of parts and shortens the time for adjusting the resonance frequency by the frequency adjustment screw.

[0005]

According to a first aspect of the present invention, there is provided a dielectric resonator device, wherein a conductive shield covering the dielectric resonator is provided with a screw hole, and a frequency adjusting screw is screwed into the screw hole. In the dielectric resonator device in which the distance between the dielectric resonator and the tip of the frequency adjusting screw is changed to adjust the resonance frequency, the frequency adjusting screw may be mounted on the crest of the screw thread along the crest. It has a groove.

According to a second aspect of the present invention, in the dielectric resonator device, the screw portion of the frequency adjusting screw or the screw hole of the conductive shield has a non-circular cross-sectional shape, and the screw portion or the screw hole. The maximum diameter portion where the distance from the center axis of the screw thread to the crest of the screw thread becomes the maximum value is provided at a plurality of positions in the circumferential direction.

In the dielectric resonator device according to a third aspect of the present invention, the maximum diameter portion is provided at an equiangular position in a circumferential direction.

In a dielectric resonator device according to a fourth aspect of the present invention, the maximum diameter portion is provided at three locations in a circumferential direction.

In the dielectric resonator device according to a fifth aspect of the present invention, the vicinity of the root of the thread is formed as a wide-bottom concave portion cut out inward from the extension surface of the flank.

A dielectric resonator device according to a sixth aspect of the present invention is constructed by providing a conductive shield with a plurality of frequency adjusting screws.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Hereinafter, the same or similar components in the respective drawings are denoted by the same reference numerals. FIG. 1 is a sectional view showing a first embodiment of the dielectric resonator device according to the present invention. The dielectric resonator device 1 includes a dielectric resonator 5 in a conductive shield 2, and a frequency adjusting screw 4 is screwed into a screw hole 3 on the upper surface of the conductive shield 2. . FIG. 2 is an enlarged cross-sectional view showing the screwing of the screw hole 3 and the frequency adjusting screw 4 of the dielectric resonator device 1 of FIG. 1 and including the axis. The frequency adjusting screw 4 is provided with a thread 14 having the same flank angle as the pressure side flank angle and the play side flank angle, and is provided with a groove 26 having a groove width t along the crest 25 thereof.

The threads 14 are formed to have a desired pitch P. The flanks 24 on both sides of the thread 14
Are formed so that the flank angle A, which is the angle at which they intersect, also has a desired value. The flank angle A is usually set to 60 degrees. The position of the effective diameter D (central height of the thread) of the screw is indicated by a two-dot chain line. The valley portion of the thread 14 is formed as a wide-bottom concave portion 33 having a shape that is cut inward from the extension surface of the flank 24 on the valley bottom side from the effective diameter D. The bottom surface of the wide-bottom concave portion 33 is formed to be relatively flat wider than a conventional screw groove. Also, the side surface 32 of the wide-bottom concave portion 33
Is set to be smaller than the flank angle A. When the flank angle A is 60 degrees, the side surface 3
2 is, for example, 20 to 40 degrees (preferably 25 to
35 degrees). Due to the small tolerance angle of the side surface 32, the wide-bottom concave portion 33 has a substantially rectangular shape in the cross section of the thread 14.

The groove 26 of the screw thread 14 is
Flank 23 which is the slope of thread 13 engraved on
And a flank 24 which is a slope portion of the screw thread 14 engraved on the frequency adjusting screw 4, a force in a direction to close the groove 26,
The grooves 26 are formed so as to be in contact with each other while maintaining a balance with the repulsive force due to the elasticity of the grooves 26.

The adjustment of the resonance frequency is performed by changing the gap d with the dielectric resonator 5 by rotating the frequency adjustment screw 4 up and down. At this time, at the contact surface between the flank 24 of the frequency adjusting screw 4 and the flank 23 of the screw hole 3,
A frictional resistance is generated due to elastic stress and contact so as to maintain a fastening state without a gap or looseness. When the frequency adjusting screw 4 is tightened into the screw hole 3, the fastening state always has a predetermined fastening force. become. In such a state, even if vibration or impact external force is applied, relative slip does not occur between the screw thread 13 of the screw hole 3 and the screw thread 14 of the frequency adjusting screw 4, and the frequency adjusting screw 4 While preventing rattling and loosening,
Since the groove 26 provided on the peak 25 serves to release those external forces, a stable fastening state can be maintained for a long time.
In the dielectric resonator device 1, the resonance frequency fa with respect to the gap d between the frequency adjusting screw 4 and the dielectric resonator 5 is determined.
Is approximately 100 kHz / μm.

The wide-bottom concave portion 3 is located near the root of the thread 14.
When 3 is provided, since the material of the screw material plastically moves toward the crest of the screw thread 14, the depth of the groove 26 is formed deeper than when the wide-bottom concave portion 33 is not provided. Therefore, the flank is easily elastically deformed, and the fastening effect is improved. Furthermore, since the root of the thread 14 is widened as the wide-bottom concave portion 33 and the curvature changes relatively smoothly, stress concentration hardly occurs at the root, and stress fracture and fatigue fracture hardly occur.

Japanese Patent Application Laid-Open No. H8-177839 discloses a loosening prevention screw in which both flank angles of a screw thread are different. However, when the screw is not completely tightened, the screw is actuated by an axial spring back action. Could loosen. On the other hand, in the frequency adjusting screw 4 according to the present invention,
Since both flank angles are equal, there is no risk of loosening even in the adjustment position where the flank angle is not completely tightened.

Therefore, according to the dielectric resonator device 1 of the present embodiment, when the frequency adjusting screw 4 is screwed into the screw hole 3, it is possible to always maintain the fastening state. The distance between the tip of the frequency adjustment screw 4 and the dielectric resonator 5 can be fixed at a constant value without any other fastening processing using a single component, and the adjustment of the resonance frequency can be completed. Therefore, the number of parts can be reduced, the cost can be reduced, and the adjustment time can be shortened. In addition, since chips are hardly generated as in the case of using a tapping screw, short circuit failure due to chips can be prevented. Further, the frequency adjusting screw 4 withstands repeated screw-in use, and the fastening effect is hardly attenuated, so that the durability of the dielectric resonator device 1 itself is improved. In addition, since an adhesive or resin processing for fastening is not required, the manufacturing cost can be further reduced.

FIG. 3 shows a dielectric resonator device 1 according to the present invention.
FIG. 4 is a sectional view showing a second embodiment of the present invention, and FIG.
FIG. 4 is a sectional view taken along line AA of FIG. The cross-sectional shape of the screw portion 6 of the frequency adjusting screw 4 is non-circular, and has a substantially triangular shape with three surfaces bulging outward. The distance from the central axis of the screw portion 6 to the outer periphery (the tip of the screw thread) of the screw portion 6 has a maximum value at the maximum diameter portion 11 and a minimum value at the minimum diameter portion 12. The maximum diameter portion 11 is 3 at every equal angle of 120 degrees in the circumferential direction of the screw portion 6.
It is provided in places. Three minimum diameter portions 12 are also provided at equal angles of 120 degrees in the circumferential direction of the screw portion 6. The minimum diameter portion 12 is located at an intermediate angular position between the maximum diameter portion 11 and the maximum diameter portion 11. In the vicinity of the three maximum diameter portions 11, screw threads 14 are provided.
Are formed.

The ratio of the distance from the central axis of the screw portion 6 to the maximum diameter portion 11 and the distance from the central axis to the minimum diameter portion 12 is:
It is about 1: 0.8. The ratio of these distances is 1: (0.7
To 0.9). The distances from the central axis of the screw portion 6 to the three maximum diameter portions 11 are all equal. However, three minimum diameter portions 1 from the central axis of the screw portion 6
The distances to 2 need not all be equal.

The number of the maximum diameter portions 11 on the outer periphery of the screw portion 6 is not limited to three, but may be plural such as four or five, but an odd number is preferable to an even number. In addition, from the viewpoint of ease of manufacture and compatibility with the screw hole 3, it is most preferable to provide three places and make a substantially triangular shape. Further, the thread 14 may be provided not only in the vicinity of the maximum diameter portion 11 of the screw portion 6 but also in the entire circumference. In addition, a groove 26 similar to that of the first embodiment is formed in the crest 25 of the screw thread 14.

According to the dielectric resonator device 1 of the second embodiment, by forming the cross-sectional shape of the screw portion 6 into a substantially triangular shape, the screw hole 3 and the screw portion 6 do not come into contact with each other all around. Point contact at a point. For this reason, the fastening force concentrates on the three contact points, the holding force of the frequency adjustment screw 4 increases, and the frequency adjustment screw 4 is prevented from loosening even after performing the adjustment a plurality of times, thereby suppressing the frequency fluctuation. Can be. In addition, since the friction is reduced and the screwing is smooth, the frequency can be easily adjusted.

The above operation and effect will be confirmed in accordance with the experimental results shown in FIG. In this experiment, the frequency adjusting screw (first embodiment) of the first embodiment in which the cross section of the screw portion was circular,
The frequency adjusting screw (second
) Was screwed into the screw portion of the conductive shield having the same structure, and the screwing torque with respect to the frequency adjustment frequency and the fluctuation value of the adjustment frequency were compared. The screwing torque is a measured value of the rotation torque by a torque meter when the frequency adjusting screw is screwed into the screw hole, and the frequency fluctuation value is a fluctuation value of the resonance frequency after the vibration test for 6 hours. From this result, in the first embodiment, the frequency adjustment becomes easy by reducing the screwing torque with the increase in the number of adjustments, but the frequency fluctuation increases in proportion to the number of adjustments, and the standard value is obtained at the fifth adjustment. Will be exceeded. On the other hand, in the second embodiment, as the number of adjustments increases, the screwing torque decreases and the adjustment becomes easy. In addition, the loosening prevention performance does not decrease after about 10 times, so that there is almost no frequency fluctuation. Understand.

FIG. 6 is a sectional view showing a modification of the second embodiment. Here, screw holes 3 and 3a into which a large-diameter frequency adjustment screw 4 for coarse adjustment and a small-diameter frequency adjustment screw 4a for fine adjustment are screwed are provided on the upper surface of the conductive shield body 2. The thread portions of both frequency adjusting screws 4 and 4a are formed in a substantially triangular shape in cross section, similarly to the thread portion 6 shown in FIG.

According to such a dielectric resonator device 1,
Since two frequency adjusting screws 4 and 4a having a substantially triangular cross section are provided, there is no frequency variation, frequency adjustment is easy, and coarse adjustment is performed by the large diameter frequency adjusting screw 4. Fine frequency adjustment can be performed more easily, for example, by performing fine adjustment using the small-diameter frequency adjustment screw 4a.

FIGS. 7 and 8 show still another modification of the second embodiment. As shown in FIG. 7, the screw hole 3 may be formed by burring from the inside of the conductive shield 2. As shown in FIG. 8, a screw hole 3 may be formed by fitting a nut-shaped separate component. As shown in FIG. 6, the screw hole 3 may be provided by utilizing the thickness of the conductive shield 2 itself.

The present invention is not limited to the above embodiment. In the above embodiment, the case where the present invention is applied to the screw portion 6 of the frequency adjusting screw 4 has been described. However, the present invention can be applied to the screw hole 3 of the conductive shield 2. When applied to the screw hole 3, the sectional shape of the screw hole 3 may be non-circular. Also, for example, the groove 26 of the peak 25 of the frequency adjusting screw 4
May be provided in a V-shaped, U-shaped, or substantially U-shaped cross-sectional shape, or may be provided intermittently, such as provided on an arbitrary thread such as every single crest or every second crest. May be.

The material of the frequency adjusting screw 4 is not limited to a conductive metal such as iron, stainless steel, copper, aluminum and brass, and a synthetic resin which is an electric insulator such as polycarbonate can be used. Further, a conductive metal screw and a synthetic resin screw may be used in combination.
In this case, when the gap between the conductive metal screw and the dielectric resonator is narrowed, the frequency increases.On the contrary, the frequency of the synthetic resin screw tends to decrease. it can.

Further, the conductive shield 2 is made of iron (soft iron, hard iron), aluminum, copper (soft copper, hard copper), brass,
The surface may be formed of a conductive metal such as zinc die-cast, aluminum die-cast, or magnesium alloy, or its surface may be subjected to a corrosion prevention treatment with, for example, chromic acid. Alternatively, the conductive shield 2 may be formed of a synthetic resin, and the surface thereof may be plated or vapor-deposited with a conductive material.

In addition, the shape of the conductive shield 2 is formed into a cubic shape, a kamaboko shape, a bowl shape, or the like, the direction of the dielectric resonator 5 is changed, and the side surface of the conductive shield 2 opposed to the shape is formed. The purpose of the present invention, such as forming a screw hole 3 in the head, or making the head of the frequency adjusting screw 4 a pan, a flat, a round, a round or a hexagon, or a slotted or cross-shaped hole, etc. The shape and configuration of each part can be changed as appropriate without departing from the scope of the present invention.

[0030]

As described above in detail, according to the first aspect of the present invention, the frequency adjusting screw alone can always maintain the tightened state without rattling or loosening with the screw hole. The frequency can be adjusted and the cost of parts can be reduced. In addition, the adjustment of the resonance frequency can be completed only by turning the frequency adjusting screw, and the adjustment time can be reduced.

According to the second, third and fourth aspects of the present invention, since the screw portion or the screw hole is formed to have a non-circular cross section, the holding force of the frequency adjusting screw is increased by concentrating on a plurality of contact points.
The loosening effect can be enhanced.

According to the fifth aspect of the present invention, since the wide-bottom concave portion is provided near the root of the thread, the groove at the top of the thread can be formed deep, and the performance of preventing the screw from loosening can be improved.

According to the sixth aspect of the present invention, since a plurality of frequency adjusting screws are provided, fine adjustment of the resonance frequency can be easily performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a dielectric resonator device according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a sectional view of a dielectric resonator device according to a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a graph showing screwing torque characteristics and frequency fluctuation characteristics.

FIG. 6 is a sectional view showing a modification of the second embodiment.

FIG. 7 is a sectional view showing another modification of the second embodiment.

FIG. 8 is a sectional view showing still another modified example of the second embodiment.

[Explanation of symbols]

1. Dielectric resonator device 2. Conductive shield,
3, 3a screw holes, 4, 4a frequency adjustment screws, 5
..Dielectric resonators, 6 screw sections, 11 maximum diameter sections,
13, 14 ... thread, 23, 24 ... flank, 25
··· Crest, 26 ·· groove, 33 ·· wide bottom recess.

Continuation of the front page (72) Inventor Hiroshi Ozawa 80 Nogami, Asada-cho, Nisshin-shi, Aichi F-term (reference) in Maspro Denko Corporation 5J006 HC03 HC21 LA11 MA01 MB01 PA01

Claims (6)

[Claims] 1. A screw hole is provided in a conductive shield body that covers a dielectric resonator, and a frequency adjustment screw is screwed into the screw hole to increase a distance between the dielectric resonator and a tip end of the frequency adjustment screw. A dielectric resonator device capable of changing and adjusting a resonance frequency, wherein the frequency adjusting screw has a groove on a crest of a screw thread along the crest. 2. A screw portion of the frequency adjusting screw or a screw hole of the conductive shield body has a non-circular cross-sectional shape, and is formed from a central axis of the screw portion or the screw hole to a crest of the screw thread. 2. The dielectric resonator device according to claim 1, wherein a maximum diameter portion having a maximum distance is provided at a plurality of positions in a circumferential direction. 3. The dielectric resonator device according to claim 2, wherein the maximum diameter portion is provided at an equiangular position in a circumferential direction. 4. The dielectric resonator device according to claim 3, wherein the maximum diameter portion is provided at three positions in a circumferential direction. 5. The dielectric resonator device according to claim 1, wherein a portion near the root of the thread is formed as a wide-bottom concave portion cut out inward from an extension surface of the flank. 6. The dielectric resonator device according to claim 1, wherein a plurality of frequency adjusting screws are provided on the conductive shield.