JPH087602Y2 - Resistor trimming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a resistor trimming device for trimming a resistor until its resistance value reaches a predetermined target resistance value.

[Prior Art] Conventionally, this type of trimming device measures the resistance value of a resistor being trimmed by a digital meter, and when the measured value reaches a predetermined target resistor, trimming is performed on the resistor. It is designed to be automatically terminated.

Here, the digital meter means to measure the resistance of the resistor as a digital value from the voltage drop when the resistor is energized during trimming and to display the measured value digitally. A / D converter is used to integrate the voltage drop due to the resistor.
It is designed to be converted. Therefore, such a digital meter measures the resistance of the resistor at a predetermined sampling rate (for example, 2.5 times / second), and naturally, the comparison operation between the measured value and the target resistance value has the same timing. Become. Generally, a digital meter relay in which a comparator that performs such a comparison operation and a relay that operates based on the comparison result are incorporated in a digital meter is used.

[Problems to be Solved by the Invention] However, in the trimming device using the digital meter as described above, the measurement timing of the resistance value of the resistor during trimming is intermittent according to the sampling speed of the digital meter. Since the timing of measuring the resistance value of the resistor during trimming was delayed, the resistor could not be trimmed accurately until the resistor reached the target resistance value. Moreover, since the delay in the resistance value measurement timing increases with the trimming speed of the resistor,
There is a problem that the trimming speed cannot be increased.

An object of the present invention is to solve the above-mentioned conventional problems, to accurately trim a resistor until the resistor reaches a target resistance value, and to increase the trimming speed, and also to prevent defective resistors. It is an object of the present invention to provide a resistor trimming device that can also determine the degree.

[Means for Solving the Problem] A resistor trimming device of the present invention is a resistor trimming device that trims a resistor until the resistance value between its terminals reaches a predetermined target resistance value. Energizing means for flowing a constant current between the terminals of the body, and first setting means for setting a voltage between the terminals when the constant current is applied to the resistor having the target resistance value as a first reference voltage Second setting means for setting a voltage between the terminals when a constant current is applied to a resistor having a predetermined resistance value in the middle of the trimming as a second reference voltage, and the resistor being trimmed. A first comparison for continuously comparing the voltage between the terminals corresponding to the resistance value of the body and the first reference voltage, and outputting a trimming end signal when the former voltage reaches the latter voltage. Means and said trimmer A second voltage that compares the voltage between the terminals corresponding to the resistance value of the resistor being connected with the second reference voltage and outputs a failure determination signal when the former voltage reaches the latter voltage. Comparing means, and when the trimming of the resistor is terminated based on the trimming termination signal, and the trimming termination signal is not output after the trimming of a predetermined value is performed, the trimming termination signal is output depending on whether the defect determination signal is output. And a control means for discriminating and informing the degree of defect of the resistor.

[Operation] In the resistor trimming device of the present invention, a constant current is caused to flow between the terminals of the resistor being trimmed, and the voltage between the terminals corresponding to the resistance value of the resistor and the resistor exhibit the target resistance value. When the voltage of the former reaches the voltage of the latter, the trimming of the resistor is automatically terminated. Therefore, the resistance value of the resistor being trimmed is continuously monitored, and the trimming is surely ended when the resistance value reaches the target resistance value.

As a result, the resistor can be trimmed accurately until its resistance value reaches the target resistance value, and the trimming speed can be increased.

Furthermore, when the resistor does not exhibit the target resistance value after performing the predetermined amount of trimming, it is determined whether the voltage between the terminals corresponding to the resistance value of the resistor has reached a predetermined other reference voltage. The degree of defect of the resistor is also determined.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

First, the mechanical structure of the trimming apparatus of this embodiment will be described with reference to FIG. In the figure, W is a resistor to be trimmed, and this resistor W is a cylindrical body W ₁
A resistance wire for temperature compensation is wound around the outer peripheral surface of, and the end portion of the resistance wire is connected to a terminal W ₂ located on the center line of the main body W ₁ . The resistor body W is adjusted to a predetermined target resistance value by trimming the resistance wire on the outer peripheral surface thereof. 1 is a first rotation motor provided on the body frame 2 of the trimming device,
The resistor W is detachably attached to the output shaft 1a via the chuck mechanism 2.

The cylinder mechanism 3 is provided above the body frame 2.
An elevating plate 4 that is moved up and down is provided.
On the lifting plate 4, an upper pulley 6 rotated by a second rotation motor 5 and two lower pulleys 7 located below the pulley 6 and displaced in the front-back direction of the paper surface in FIG. 7 is provided, and a trimming belt 8 is laid between these three pulleys 6 and 7, 7 so as to form a triangle when viewed from the left and right direction in FIG. A portion corresponding to the lower side of the trimming belt 8 is located just above the resistor W held by the chuck mechanism 2. Further, the lifting plate 4 is provided with a tension mechanism (not shown) for giving a predetermined tension to the trimming belt.

Further, on the upper part of the main body frame 2, there is provided a movable body 11 which is slidable in the left-right direction in FIG. 2 along the guide shaft 10, and the movable body 11 further comprises a first pair of constant current supply pairs. Probes 12a and 12b and a second pair of resistance measuring pairs
Each of the probes 13a and 13b is provided so as to be vertically movable. These probes 12a, 12b and 13a, 13b are
The lower ends of the resistors are offset from each other in the left-right direction in FIG. 2, and when the moving body 11 slides to the left in FIG. 1, the lower body moves downward and is held by the chuck mechanism 2. It contacts the terminal W ₂ of W and is electrically connected to both ends of the resistance wire of the resistor W to be trimmed. Also,
The first and second probes 12a, 12b and 13a, 13b are connected to a resistance measuring circuit which will be described later, and the resistance measuring circuit and the control circuits of the respective operating parts are provided in the control panel 14 on the main body frame 2. It is equipped.

On the body frame 2, brushes 15a and 15b for brushing the surface of the resistor W being trimmed.
A brushing mechanism 15 provided with is movably arranged.

Next, the first and second probes 12a, 12b and 13a, 1
The resistance detection circuit connected to 3b will be described with reference to FIG.

A constant current circuit 21 is connected to the first probes 12a and 12b so that a constant current of the resistance wire of the resistor W flows. The second probes 13a and 13b are connected to an amplifier 22, which amplifies the voltage across the resistance wire of the resistor W and uses it as a measured voltage E _x corresponding to the resistance value of the resistor W. The first and second comparators 23 and
Enter 24 consecutively.

The first comparator 23 inputs the predetermined first reference voltage E ₁ from the _first voltage dividing resistor R ₁ connected to the constant voltage circuit 25 using the Zener diode D _z , and inputs the reference voltage E ₁ to the reference voltage E ₁ . continuously comparing said measured voltage E _x. Then the comparator 23 inverts the output when the measured voltage E _x reaches the reference voltage E _1, and outputs a trimming end signal P ₁ through the first photocoupler 26. Here, the first reference voltage E ₁ is set to a value corresponding to the target resistance value of the resistor W. Therefore, the trimming end signal P ₁ is output when the resistor W is trimmed to the target resistance value.

On the other hand, the second comparator 24 inputs the predetermined second reference voltage E ₂ from the second voltage dividing resistor R ₂ connected to the constant voltage circuit 25, and inputs the reference voltage E ₂ and the measured voltage E _{2. x} is continuously compared, and when the latter voltage E _x reaches the former voltage E ₂ , the output is inverted and the defect determination signal P ₂ is output through the second photocoupler 27. The second reference voltage E ₂ is the first
Smaller than the reference voltage E ₁ of is set to a value corresponding to a predetermined value below the target resistance of the resistor W.

The trimming end signal P ₁ and the defect determination signal P ₂ are input to the control circuit (control means) 28, and this control circuit 28 outputs both signals.
Control the trimming device based on P ₁ and P ₂ . The control content will be described later together with the operation.

 Next, the operation will be described.

First, the brushing mechanism 15 is moved to the standby position on the back side of the paper surface in FIG. 2, then the chuck mechanism 2 is caused to hold the resistor W to be trimmed, and then the moving body 11 is slid to the left to And the lower ends of the second probes 12a, 12b and 13a, 13b are brought into contact with the terminal W ₂ of the resistor W.
Thus, the circuit of FIG. 1 is formed and the resistance value of the resistor W before trimming is measured.

In the case of the normal resistor W, the resistance value before trimming is much smaller than the target resistance value, and the measured voltage _Ex becomes no smaller than the first and second reference voltages E ₁ and E ₂ ,
P ₁ and P ₂ is not output. However, when the signals P ₁ and P ₂ are output before this trimming, the resistor W is removed from the chuck mechanism 2 without trimming, and the next resistor W is set instead.

Next, the brushing mechanism 15 is moved to the position shown by the solid line in FIG. 2, the brushes 15a and 15b thereof are brought into contact with the outer peripheral surface of the resistor W, and the trimming belt 8 is predetermined by the second rotating motor 5. The elevating plate 4 is gradually lowered while rotating at the speed of. Then, from the time when the trimming belt 8 descends to the trimming work position and comes into contact with the outer peripheral surface of the resistor W, the resistor W is rotated at a predetermined speed by the first rotation motor 1 to start trimming.

Due to this trimming, the resistance value of the resistor W is gradually increased, and accordingly, the measured voltage _Ex is continuously increased, and the measured voltage _Ex exceeds the second reference voltage E ₂ and the first reference voltage E ₂ is exceeded.
Will reach the reference voltage E ₁ . Therefore, the trimming end signal P ₁ is output after the defect determination signal P ₂ is output. The control circuit 27 activates the display means such as a lamp when the defect discrimination signal P ₂ is input, and terminates the trimming operation when the trimming end signal P ₁ is input. That is, the lifting plate 4 is raised to remove the trimming belt 8 from the resistor W, and the first rotation motor 1 is stopped. The second rotation motor 5 is not stopped, and the trimming belt 8 is kept rotating in preparation for the next trimming operation.

By the way, in the case of the present embodiment, when the trimming end signal P ₁ is not output while the resistor W is rotated twice, the resistor W is regarded as defective. Resistor W that is considered to be defective
The magnitude of the resistance can be discriminated into two types depending on whether or not the defect discrimination signal P ₂ is output, that is, whether or not the display means such as a lamp that operates based on the signal P ₂ is operating.

After the trimming of the resistor W is completed, the moving body 11 is slid to the right in FIG. 2, the gripping of the resistor W by the chuck mechanism 2 is released, and the brushing mechanism 15 is moved to the second position.
As shown by the chain double-dashed line in the figure, the resistor W is slid to the right to eject the resistor W to the right in FIG.

After that, a large number of resistors W are trimmed one after another by repeating the same operation.

[Effects of the Invention] As described above, the resistor trimming device of the present invention causes a constant current to flow between the terminals of the resistor being trimmed to generate a voltage between the terminals corresponding to the resistance value of the resistor. , A configuration in which the resistance is continuously compared with a reference voltage between terminals when it exhibits a target resistance value, and when the former voltage reaches the latter reference voltage, trimming of the resistor is automatically terminated. Therefore, the resistance value of the resistor being trimmed can be continuously monitored, and the trimming can be surely ended when the resistance value reaches the target resistance value.

As a result, the resistor can be trimmed accurately until its resistance reaches the target resistance, and the trimming speed can be increased.

Furthermore, when the resistor does not exhibit the target resistance value after performing the predetermined amount of trimming, it is determined whether the voltage between the terminals corresponding to the resistance value of the resistor has reached a predetermined other reference voltage. By also determining the degree of defect of the resistor, a special inspection process for determining the degree of the resistor is unnecessary, and work efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an essential part showing an embodiment of the present invention, and FIG. 2 is a front view of the trimming device shown in FIG. 21 …… Constant voltage circuit (energizing means), 23,24 …… Comparator (comparing means), 26 …… Constant voltage circuit, 28 …… Control circuit (control means), W …… Resistor, E _x …… Measurement Voltage, E ₁ , E ₂
…… Reference voltage, P ₁ …… Trimming end signal.

Claims (1)

[Scope of utility model registration request] 1. A resistor trimming device for trimming a resistor until the resistance value between its terminals reaches a predetermined target resistance value, an energizing means for flowing a constant current between the terminals of the resistor being trimmed, First setting means for setting a voltage between the terminals when a constant current is applied to a resistor having a target resistance value as a first reference voltage; and a resistor having a predetermined resistance value at an intermediate stage of the trimming. Second setting means for setting a voltage between the terminals when the constant current is applied to the body as a second reference voltage; a voltage between the terminals corresponding to a resistance value of the resistor being trimmed; Continuously comparing with the first reference voltage,
First comparing means for outputting a trimming end signal when the former voltage reaches the latter voltage, the voltage between the terminals corresponding to the resistance value of the resistor being trimmed, and the second reference voltage And a second comparing means for outputting a failure determination signal when the former voltage has reached the latter voltage, and the trimming of the resistor is terminated based on the trimming termination signal, and a predetermined amount When the trimming end signal is not output after the trimming is performed, the control means for determining the defect degree of the resistor according to the output of the defect determination signal and notifying the defect is provided. Body trimming device.