JPH04511Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a slide switch, and more particularly, to a slide switch that switches connections between a plurality of terminal members by means of a sliding contact piece that slides together with a slider.

2. Description of the Related Art Conventionally, slide switches as shown in FIGS. 6 and 7 have been used for switching, for example, the oscillation frequency band of an oscillation circuit. In both figures, terminal members 2a to 2l are implanted through the substrate 1 with their respective terminal portions protruding. The slider 3 is formed of an insulating material, and has grooves 3a corresponding to the terminal parts of the terminal members 2a to 2f on the bottom surface, and grooves 3a corresponding to the terminal parts of the terminal members 2g to 2l.
A groove 3b corresponding to the terminal portion is bored, and a recess is provided near both ends of each of the grooves 3a and 3b. Elastic metallic sliding contacts 4 to 7 are housed in each of the recesses of the slider 3.
Each of the sliding contact pieces 4 to 7 has a pair of contact portions, for example, the contact portions 4a and 4b of the sliding contact piece 4 sandwich the respective ends of the terminal members 2a and 2b, and the other sliding contact piece 5 ~
7 also holds the terminal part in the same way, and slide the slider 3
is placed on the substrate 1. The cover 9 is made of a conductive material and has an opening window 10. The cover 9 covers the slider 3 by inserting the knob 8 of the slider 3 and protruding from the opening window 10, and is fixed to the substrate 1 to prevent externally induced noise from entering.

By pushing the knob 8, the slider 3 slides in the direction of the arrow _A1 or _A2 relative to the substrate 1 and the cover 9. By sliding the slider 3 in the _two directions of arrow A, the sliding contact piece 4 connects the terminal members 2a and 2b, and by sliding in the _one direction of arrow A, the sliding contact piece 4 connects the terminal members 2b and 2c. do. Other sliding contact pieces 5 to 7
Similarly, two of the terminal members 2d to 2l are connected.

Problems to be Solved by the Invention FIG. 8 shows a sectional view taken along the - line shown in FIG. 7. In the conventional slide switch, as shown in FIG.
c~3f are slightly larger than the sliding contact piece,
The sliding contact pieces 4 to 7 are accommodated in the recesses 3c to 3f, respectively, with a clearance. This is slider 3
This is to improve the sliding properties of the substrate 1 on the substrate 1.

Here, for example, the sliding contact piece 4 is surrounded by an insulating material, and the sliding contact piece 4 and the side plate parts 9a, 9 of the cover 9 are
There are stray capacitances Ca, Cb,
Cc occurs. This stray capacitance is inversely proportional to the distance between the slider 4 and the side plates 9a, 9b and top plate 9c. Since there is a clearance between the sliding contact piece 4 and the recess 3c, the floating capacitances Ca to Cc change as the slider ₉ slides in the directions of arrows A1 and _A2 . Since the sum of the distances between the sliding contact piece 4 and the side plate parts 9a and 0b is constant, the sum of the stray capacitances Ca and Cb is approximately constant, but the distance between the sliding contact piece 4 and the top plate part 9c is The stray capacitance Cc changes due to the change. For this reason, for example, if the knob 8 is received in the state of the knob ₈ shown in _FIG . However, due to the change in stray capacitance, there were cases in which the previously received shortwave broadcast could not be received.

Therefore, an object of the present invention is to provide a slide switch in which changes in stray capacitance are almost eliminated by reducing the amount of insulating material (dielectric material) between the sliding member and the cover.

Means and Effects for Solving the Problems The present invention provides a method for connecting a sliding contact that is swingably housed in a storage section on the bottom side of an insulating slider and a cover made of a conductive material that covers the top side of the slider. A through hole is provided in the thick part of the slider that extends from the slider's sliding contact housing to the top surface, thereby reducing the amount of insulating material that forms the slider and reducing the stray capacitance between the sliding member and the cover. It is constructed so that the capacitance changes are small and there is almost no change in capacitance, and each embodiment thereof will be explained with reference to FIG. 1 and subsequent figures.

Embodiment FIGS. 1A and 1B show a cross-sectional view and a longitudinal sectional view, respectively, of a first embodiment of the switch of the present invention. In this figure, the same parts as in FIGS. 6 to 8 are designated by the same reference numerals, and their explanations will be omitted. In FIGS. 1A and 1B, 13 is a slider made of an insulating material. Slider 13
Terminal members 2a to 2a protruding from the board 1 are provided on the bottom surface of the board 1.
Grooves 13 corresponding to the respective terminal parts of 2f, 2g to 2l
a and 13b are bored as shown in FIG.
Near both ends of the groove 13a, through holes 13c and 13d are provided as housing portions for sliding contact pieces, penetrating from the bottom surface to the top surface of the slider 13, and similarly, through holes 13e and 13f are provided in the groove 13b. .

The cross section of the through hole 13c near the bottom surface of the slider 13 is slightly larger than the sliding contact piece 4. In addition, wedge-shaped regulating portions 13c ₁ and 13c ₂ are left on the upper surface side of the sliding contact piece 4 of the through hole 13c, and extend from the lower end of each of the regulating portions 13c ₁ and 13c ₂ to the lower surface of the slider 13. The distance is approximately the same as the height of the sliding contact piece 4. A sliding contact piece 4 is housed in the through hole 13c, and the sliding contact piece 4 is connected to the slider 13.
The movement toward the upper surface side is restricted by the tips of the restriction portions 13c ₁ and 13c ₂ . Each of the through holes 13d to 13f has the same structure as the through hole 13c, and each has a regulating portion.

Sliding contact pieces 4 to 7 are accommodated in the through holes 13c to 13f of the slider 13, respectively.
The slider 13 is placed on the substrate 1 with the terminal portions of the terminal members 2a to 2l being held between the respective contact portions, and is further covered with a cover 9.

In this way, for example, the sliding contact piece 4 has the regulating portion 13c ₁ ,
13c _{and 2} , and a space of a through hole 13c is provided between the sliding contact piece 4 and the top plate portion 9c of the cover 9, and there is almost no insulating material (that is, dielectric material) existing between the sliding contact piece 4 and the top plate portion 9c of the cover 9. Stray capacitance Cc becomes smaller than before. Further, the height from the lower surface of the slider 13 to each of the regulating portions 13c ₁ and 13c ₂ is approximately the same as the height of the sliding contact piece 4. Therefore, even if the slider 13 is slid by pushing the knob 8, the distance between the sliding contact piece 4 and the top plate portion 9c hardly changes, and even if this distance changes slightly, the stray capacitance Cc
is smaller than before, so there is almost no change in capacitance.

3A and 3B show a cross-sectional view and a vertical cross-sectional view, respectively, of a second embodiment of the switch of the present invention. In this figure, the same parts as in FIGS. 1A and 1B are given the same reference numerals, and their explanations will be omitted. 23 is a slider, which has grooves 13a,
Grooves 23a and 23b similar to 13b are bored as shown in FIG.
f is provided. The through hole 23c is the slider 2
3. A first portion 23c 1 whose cross section on the bottom side is slightly larger than the sliding contact piece 4, and a second portion 23c ₂ whose cross section on the top side of the slider 23 is smaller than the sliding contact piece _4.
Therefore, the first part 23c ₁ and the second part 23
A step portion 23c 3 serving as a regulating portion is formed between the step portion _{23c 2} and the step portion 23c ₃ . The distance from the bottom surface of the slider 23 to the stepped portion _23c3 is approximately the same as the height of the sliding contact piece 4. Each of the through holes 23d to 23f also has the same structure as the through hole 23.

For this reason, for example, the sliding contact piece 4 is regulated by the stepped portion _23c3 , and a space of a through hole 23c is provided between the sliding contact piece 4 and the top plate portion 9c of the cover 9, so that the stray capacitance Cc
is smaller than before. Therefore, as in the first embodiment, even if the slider 23 is slid, the sliding contact piece 4
The distance between the top plate portion 9c and the top plate portion 9c hardly changes, and even if this distance changes slightly, there is almost no change in the capacitance of the stray capacitance Cc.

The slide switches shown in FIGS. 1A, B and 3A, B are applied to the circuit shown in FIG. The circuit shown in FIG. 5 is, for example, a front end section of a tuner that receives medium waves and short waves. The high frequency signal received by the antenna entering terminal 30 is sent to switch S ₁
The high frequency signal selected for tuning is supplied to the base of the transistor _Q1 via the switch _S2 . transistor
A signal from a local oscillator 32 is supplied to the emitter of Q ₁ , and the intermediate frequency signal taken out from the collector of transistor Q ₁ is outputted from switch S ₃ via intermediate frequency transformer 33 and from terminal 34 .

The slide switch of the present invention is applied as the switches S ₁ to _{S 3} and the switch S ₄ in the local oscillator 33.

Here, assuming that the switch _S4 is connected to each of the terminal members 2a to 2c, in order to receive medium waves, the knob 8 is pushed in the direction of arrow _A2 , and the sliding contact piece 4 is connected between the terminal members 2a and 2b. When connected, local oscillator 3
The oscillation frequency _M of 2 is expressed as follows.

However, C' = C ₂ + C ₃ + C ₄ + C _S C _S is the stray capacitance of switch S _4. Also, when connecting terminal members 2b and 2c with sliding contact piece 4 to receive short waves, the oscillation frequency _S is as follows. It is expressed as follows.

However, C″=C ₅ +C ₆ +C ₇ +C _S Even if the above switch S ₄ changes its connection, _the stray capacitance C _S hardly changes as mentioned above. The oscillation frequency of the switch hardly changes and stable reception can be performed.The same applies to each of the other switches _S1 to _S3 .

Effects As described above, the slide switch of the present invention is a slide switch that connects a plurality of terminal members using a sliding contact piece housed in an insulating slider, and switches the connection between the terminal members by sliding the slider. In this case, the sliding contact of the slider is placed in the thick part of the slider between the sliding contact that is swingably stored in the storage part on the bottom side of the slider made of insulating material and the cover of the conductive material that covers the top side of the slider. Since there is a through hole extending from the storage part to the top surface, the amount of dielectric between the sliding contact piece and the cover is reduced, resulting in a small stray capacitance.
When the distance between the sliding contact piece and the cover changes due to sliding of the slider, there is almost no change in the stray capacitance, and the oscillation frequency is stabilized even when used to switch the oscillation frequency of an oscillator, for example. It has the following features:

[Brief explanation of the drawing]

1 and 3 are a cross-sectional view and a longitudinal sectional view of each embodiment of the switch of the present invention, and FIGS. 2 and 4 are perspective views of the main parts of the switch shown in FIGS. 1 and 3, respectively. ,
FIG. 5 is a circuit diagram of an embodiment of a tuner to which the switch of the present invention is applied, and FIGS. 6 to 8 are diagrams for explaining conventional switches. 1... Board, 2a to 2l... Terminal member, 3, 1
3, 23...Slider, 4-7...Sliding contact piece, 8
...Knob, 9...Cover, 13a, 13b, 23
a, 23b...groove, 13c-13f, 23c-2
3f...Through hole, 13c ₁ , 13c ₂ ...Restriction part, 2
3c ₃ ...Dan section.

Claims (1)

[Scope of utility model registration request] In a slide switch that connects a plurality of terminal members by a sliding contact piece housed in an insulating slider and switches the connection between the terminal members by sliding the slider, a storage part on the bottom side of the insulating slider. A through hole extending from the sliding contact housing portion of the slider to the top surface is formed in the thick wall part of the slider between the sliding contact housed so as to be able to swing therein and a cover made of a conductive material that covers the top side of the slider. A slide switch with a