JPS58175805A - Variable resistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention The present invention provides a variable resistor circuit that connects a load resistor in series to a variable resistor, applies load voltage, and adjusts the variable resistor to adjust the load power of the load resistor. This is related to the resistance curve of the variable resistor, and aims to prevent failures such as local burnout of the variable resistor, expand the adjustment range, and downsize the variable resistor.

Conventionally, in the variable resistor described above, for example, the resistance curve of the resistance part of the resistor that the slider fixed to the rotating shaft comes into sliding contact with is not appropriate, so when adjusting the resistance, the load power is lost at one or even several places in the resistance part. As a result, the temperature rises locally as a result of exceeding the allowable range, resulting in accidents such as local burnout and disconnection of the resistor. As a countermeasure to this problem, a high-power wire-wound variable resistor with a large linear resistance curve was used.As a result, the variable resistor is large, has a narrow resistance adjustment range, and is expensive. The variable resistor mentioned above is used in car audio equipment, etc., and as the output increases, it is used to adjust the volume of a pair of speakers in the case of a 2-channel speaker/stem, etc. The above-mentioned resistors that are used as such are required to have high power. However, because the size of automobile dashboards that house audio equipment is limited, the variable resistors that can be used are required to be smaller. has been done.

The present invention solves the above-mentioned drawbacks of the conventional variable resistor of this type, and aims to provide a variable resistor that is small, has few failures, has a wide adjustment range, and is inexpensive. An example will be explained with drawings.

FIG. 1 is a cross-sectional assembly view of an embodiment of the variable resistor of the present invention, FIG. 2 is a perspective view of a resistor board assembly in the same embodiment, and FIG.
A) is a circuit diagram of the same embodiment, FIG. Figure 1 shows the power load distribution corresponding to ΔR, and Figure '0) is a diagram showing the resistance curve of the variable resistor of the present invention.

In Figure 1, which shows a standard variable resistor, and Figure 2, which shows a resistor board assembly, l is a horseshoe-shaped resistor made of metal glaze or carbon resin/film, and is fixed on an insulating substrate 2 made of ceramic or the like. has been done. Reference numerals 7 and 71 designate metal terminals, which are connected to both ends of the resistor 10 and fixed to the substrate 2 as shown in FIG. 3 is a slider made of a conductive elastic metal plate/a slider holder 4 made of an insulator attached to the Yant 5
The shaft 5 is rotatably pivoted to a bearing 9 fixed to the substrate 2. The tip elastic contact portion of the slider 3 slides against the resistor 1 to adjust the resistance. Substrate 2
The slider 6 made of an elastic metal plate is fixed to the slider 3.
It is connected and fixed to a terminal 8 made of metal on the substrate 2 in sliding contact with the terminal 8 .

Here, as the most common power load circuit for a variable resistor, the partial load power of the variable resistor's resistor when a constant load resistance Rs is connected in series with the variable resistor and a constant load voltage V volts is loaded. Consider.

When the power supply voltage has a constant internal resistance, it can be regarded as a constant equivalent load resistance R8 in addition to the load resistance R8.

If the adjustment resistances of the variable resistor are R and J, the load power of the variable resistor W = V・cm,・■TI2,', W=soR・・・(6
)(R0R,).

This will be explained below with reference to FIG. 4(a). Let R ohm be the adjusted resistance of a variable resistor connected in series with a constant load resistance R 8 ohm. Here, it is convenient to express the adjustment resistance value R of the variable resistor as R/R8 using the load resistance R8 as a reference.
In FIG. 4(A), the resistance of the variable resistor is gradually increased from 0 on the horizontal axis, and the resistance of the variable resistor is ring-shaped and its width is constant for convenience.

When the adjustable resistor R of the variable resistor is gradually increased from 0, the angle of the ring-shaped resistor through which the current flows with respect to the adjustable resistor R is θ, the total rotation angle of the variable resistor 4, that is, the total resistance angle θ1, this As shown in Figure 4 (a), the current flowing through the resistance R portion of the variable resistor, that is, the angle θ of the resistor, is the maximum current when the resistance R is 00. 1
00chi and J,'s/RS =0.1.2.4.
100 chi, 50 chi, 33%, 20 for 10 respectively
%, 9%. Then, the total power consumption W watts of the variable resistor is W=R・G, and as shown by the broken line, R/Rs=
It reaches its maximum at i and gradually decreases around that point.

Next, as shown in FIGS. 3(a) and 3(b), turn the shaft 5 to position the slider 3 at a position of resistance value R1 and resistance angle θ, and calculate the current at this time. Next, when the slider is rotated 409 times, the resistance value increases by ΔR and the current decreases, resulting in ■7-Δμ.

becomes. Here, the local load power corresponding to the resistance angle increase Δθ, which is the local resistance area increase, is 1·ΔR. Here, this local load power G・ΔR is the local area of the resistor Δθ
The local area Δθ of the resistor, which is determined by the rising temperature, becomes equal to the local load power. Here, the heat dissipation power wj per unit surface jet is a constant value if the temperature rise J is constant, and if the width of the resistor is constant, it is proportional to the area of this local resistor ΔR, that is, the angle Δθ. , angle Δ
By making θ proportional to the load power G·ΔR in this portion, the local temperature rise in the resistance changing portion ΔR of the resistor can be made constant. When you add anhydrous water to the formula, you get the following equation. ■=・ΔR<Δθ... (7) Next, when adjusting the variable resistor of the variable resistor circuit in which the load resistor R11 is connected in series as shown in Fig. 3 (b), the local An example of creating a resistance curve for a variable resistor with uniform resistance temperature rise will be explained. Here, the total resistance R4 of the variable resistor is divided into n segmental resistances ΔR, that is, ΔR1, ΔR2...Δ
Divide into Rn. Next, find the square of the maximum current of each part for each segmental resistance ΔR, and calculate each ΔR・G.
R Σ-Σ--・■= ...(8) K=l Expressed as S. Then, the angle Δθ (the length may be used) of the segmented resistance ΔR of each resistance value is represented by Δθ3, Δθ2, . . . - by Δθ4. Here, the total resistance angle, θ, is □θ
−θ,ノ' ”IR/Σ−−−+,)t R
.

If so, it is possible to keep the temperature rise of the local resistance of the resistor of the variable resistor constant when the variable resistor is partially loaded.

Next, an example of a resistance curve design method will be explained using calculations and drawings. Here, the total resistance value Rt of the resistor is 10 times the load resistance Rs, and the resistance value may be divided into equal parts, but for simplicity, the resistor O of a normal variable resistor is used.

According to the manufacturing method of R/R80, 5, 1, 2, 4, 1, ^ 10, the resistor is divided into 6 parts, and each part is 0 to 0.5.
0.5~1・-1 7~10, same minus is 0.5.0
．． 5.1.2.3.3. At this time, electrician 8 is (5
) formula and Figure 4 (a), compared to R = 00 maximum current, it becomes 100.61.58.33.20.13, and Eni is also 100.44.25.10.5.4 ．．
It becomes 1.6 inches. Next, add ΔR to this.

Multiplying each by ΔR/R, -6-・manufacturing is 50.2
It becomes 2.25.21.12.5%, and the above sums up Σ
=135. Since only the relative ratio matters here,
The numerical values are organized by the most convenient value of 〇 Angle θ, 10Q%
When expressed in chi, Δθ is 37.16.3.18.5.
15.5.8.9.3.7 Chi, and θ is 37.5
3.3,? 1.8.87.3.96.2.100 chi. The angle θ is shown by adding each. The above is shown below. LI (1) (2) (3L (4) <5)
(6) I R/RsD, 5 1 2
47 10 ■ section (R/R11) 0~0.50
．． )-11~22~44~71~10I (ΔR) ΔR
/R50,50,51233 ■Current engineering R1006
750332013V (current)”/100100
44 25 10.5 4 1.6%/l
IR/B-・Engineering: /10ro 50 22
25 21 12 5■Δθ
(%) 37 16.318.5 15.58.
9 3.7Vll θ (%) 37 53.3
71.887, 3 96.2 100 Here, the current ■8 for the segmented resistance ΔR/R in Figure 4 (a) is the resistance of each resistor Δ
The maximum current of R/R11 is applied, and the power load distribution ΔR/R6·12 corresponding to the segmental resistance ΔR is displayed using narrow-pitch broken lines. In addition, Fig. 4 (middle) shows the change in resistance value R/RS with respect to the rotation angle θ of the shaft of the variable resistor. Also, here R/R is set to mtzx l Q, but even if R/R is set to 10Q or 1000, the resistance curve shown in Figure 4 (b) only changes slightly near the right end of 100 inches, but there is no big difference overall. The adjustment range of the variable resistor can be adjusted quite widely.

In the circuit described above, (1) When the variable resistor is used with its resistance value R changed, the load power of the entire variable resistor and local load power changes depending on the position of the slider.

(2) When the resistor is a curved resistor, the load power per unit surface area differs in each part, and the temperature rise also differs, and the above varies widely depending on the position of the slider.

(3) Then, only when the local temperature rise when changing the resistance value R of the variable resistor shown in equation (7) is constant or constant, the variable resistor Failure due to local overload and temperature rise can be prevented.

(4) Then the resistance curve of the resistor of the variable resistor is (7
) The maximum load can be applied to a variable resistor using a variable resistor when the load resistor R8 is connected in series, which is the most common usage of a variable resistor, using a resistance curve that keeps the local temperature rise due to resistance change constant. It is possible to obtain a resistance curve that allows

Here, both ends of the resistor may be somewhat relaxed due to the influence of heat conduction at the ends. Here, the temperature rise of the partial resistor R through which the current of the resistor part R7 flows is, since the load power of this resistor part is R · h2, the temperature rise at the partial load is proportional to h2, but the partial resistance of the resistor board Since there is heat conduction in the circumferential direction of R, that is, in the sliding direction of the slider, it may be relaxed to some extent within the local range. It is possible to provide a variable resistor that is small, has few failures, has a wide adjustment range, and is inexpensive, and the practical effects are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional assembly view of an embodiment of the variable resistor of the present invention, FIG. 2 is a perspective view of a resistor board assembly in the same embodiment, and FIG.
A) is a circuit diagram of the same embodiment, FIG. 4B is a load circuit diagram of the same embodiment, and FIG. A diagram showing the corresponding power load distribution, and a diagram showing the resistance curve of the variable resistor of the present invention. 1: Resistor, 2: Substrate, 3: Slider, 4: Slider bone, 5: Shaft, 6: Current collector, 8: Current collector terminal, 7α, 71α: Resistor terminal, 9: Bearing. Patent applicant: Teikoku Tsushin Kogyo Co., Ltd. Agent
Hisataka Nene Figure 1 (A)] Shiri Mata Hittingun (R1) Figure 4 (C1 Amendment to procedures other than e (method) % formula % 1, Indication of the case 1989 1% Application No. 208931 No. 2, Title of the invention Variable resistor 3, Relationship to the case of the person making the amendment er #'T Name of the person making the amendment
Teikoku Tsushin Kogyo Co., Ltd. 4, Agent
〒 tSO (2) Contents of column 7, Supplement 1E of brief explanation of drawings in the specification

Claims (3)

[Claims] (1) When adjusting the variable resistor of a variable resistor circuit in which a load resistor R8 is connected in series to the variable resistor, the position of the slider on the resistor is θ, and the adjusted resistance value at that time is is R, and the change in the adjustment resistance value when the slider position is changed by Δθ is Δ
A variable resistor with a resistance curve that maintains a constant temperature rise in the local area of the resistor corresponding to the partial load power ΔR, fII in the local area Δθ' ( (2) Continuous n of the total resistance value R6 of the resistor of the variable resistor
The resistance value R, that is, RlRt...R, and the slider position θ, that is, θ1θ2...θ, and the resistance 7L''1 are divided into sections ΔR1, that is, ΔR3, ΔR■...ΔRn, and then the segmented resistance ΔR The maximum current of each part for each part, squared I:
Find ΔR/R1・G for each t and calculate 1ΔR. The total value Σ=Σ−-I is determined, and each resistance division %, R
. The section area of the slider with respect to ΔR is ΔθIll, Δθ1Δ
When R Δθ, - - Δθ7, Δθ work θt-H,, ft
The variable resistor according to claim 1, which has a resistance curve of +/Σ. (3) The variable resistor according to claim 1, which has a resistance curve using 1.5 to 2 instead of the rainbow power of 2 of ΔR/R,·G.