JP2510808Y2 - Resistance meter with detachable probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an ohmmeter equipped with a detachable probe, and more particularly to a structure of a connection portion between the probe and the apparatus main body.

Conventionally, an insulation resistance meter is used for insulation between the output side terminal and the ground, between a breaker and the ground, and for measuring a high resistance value. This insulation resistance tester usually consists of the main body of the device and two test probes provided therein. Each of the test probes has a connecting portion at the front end, an inserting portion at the rear end, and an insulating coating portion at the middle, and the inserting portion is detachable by inserting it into or removing it from an input terminal provided in the apparatus body. At the time of measurement, as shown in FIG. 2, with respect to the apparatus main body 10, first insert the earth probe 12 into the earth (high potential) terminal 14 and the line probe 16 into the line (low potential) terminal 18, and then The connection parts 20 and 22 are connected to both ends of the DUT 24, respectively. Next, a known voltage E, for example 1000V, is applied to the DUT 24 from the device body 10 through both the probes 12 and 16, the current I flowing therethrough is detected, and the resistance value R is set to R =
Measure based on the E / I formula. At this time, both probes 12, 1
If 6 is partly touched or placed on a desk, etc., pass the ground probe 12 to the line probe 16 through the desk.
There is a current I ′ flowing on the surface of the insulating coating in the direction of the arrow. Especially in high humidity. This leakage current I'adds to the detection current I via the line terminal 18 and flows into the resistance value measuring circuit 26 inside the apparatus main body 10, so that a measurement error occurs.

Therefore, normally, the device body 10 is provided with a guard terminal 30 which is connected to the common potential (OV) line 28 of the internal circuit 26 through a resistor 29, and one end of the guard terminal 30 is insulated from the line probe 16 by using a bare wire 32. Wrap around the coated surface and the other end around the guard terminal 30. Then, the leakage current I ′ flows from the guard terminal 30 to the common potential line 28 through the bare wire 32, and its influence can be eliminated. In the needle type, the resistance value R is directly indicated by the voltage V and the current I, but in the digital type, it is calculated and digitally displayed.

Problems to be Solved by the Invention However, in order to remove such leakage current I ′, a bare wire is used.
If 32 is used, winding work is troublesome when connecting the line probe 16 and the guard terminal 30, and it takes time to prepare for measurement. Moreover, the connection state is not constant, and if the connection is bad, the leakage current I'flows into the internal circuit 26, and accurate resistance measurement cannot be performed. The independent bare wire 32 may be lost.

The present invention has been made in view of such conventional problems, and a detachable probe that can perform accurate measurement by shorting the preparation time for measurement and removing leakage current without using a bare wire. The purpose of the present invention is to provide an equipped resistance meter.

Means for Solving the Problems Means for achieving the above object will be described below with reference to FIG. 1 corresponding to the embodiment.

An ohmmeter equipped with this detachable probe is equipped with a detachable probe 34 having a connecting portion at the front end, a plug-in portion 38 at the rear end, and an insulating coating portion 36 at the middle in the device main body 40, and the difference between the probe 34 at the time of measurement. The inserting section 38 is used by inserting it into a receiving section 64 provided at the input terminal 44 of the apparatus body 40 and connected to the resistance value measuring circuit. In addition, the current collector 50 is brought into close contact with the insulating coating surface of the probe 38, and the contact body 52 connected to the current collector 50.
Are arranged in the vicinity of the insertion portion 38, and the probe 34
The contact body 70 facing the contact body 52 of the
The contact body 70 of the input terminal 44 is connected to the common potential line 76 of the circuit by arranging it in the vicinity of the receiving portion 64 of 44.

Then, the insertion portion 38 of the probe 34, the current collector 50, and the contact body 52.
Are made cylindrical, and the contact body 52 is provided on the outside of the insertion portion 38.
Are arranged coaxially, and the receiving portion 6 of the input terminal 44 of the device main body 40 is further arranged.
4, the contact body 70 is formed into a cylindrical shape, and the contact body 7 is provided outside the receiving portion 64.
It is preferable to arrange the 0s coaxially.

Operation With the above-described configuration, the probe 34 can be attached with one touch by inserting it into the input terminal 44 of the apparatus body 40. At that time, the insertion portion 38 of the probe and the receiving portion 64 of the input terminal 44 come into contact with each other, and the connection portion of the probe 34 is connected to the resistance value measuring circuit of the device body 40. At the same time, the contact body 52 of the probe 34 is an input terminal.
The current collector 50 of the probe 34 is connected to the common potential line 76 of the circuit via the contacts 52 and 70. Therefore, at the time of measurement, the current flowing through the object to be measured enters the resistance value measuring circuit from the connecting portion of the probe 34 through each conductor connected thereto, and the leakage current flowing on the insulating coating surface of the probe 34 is from the current collector 50. , A common potential line through each conductor connected to it
Enter 76. Therefore, connect the probe 34 to the input terminal of the device body 40.
Leakage current can be removed just by inserting it into 44. Of course, after the measurement is completed, the probe 34 can be removed from the input terminal 44 of the device main body 40, and the insertion portion 38 and the receiving portion 64, the contact bodies 52, 70 can be separated and easily removed.

Then, the cylindrical current collector 50 is in close contact with the outer periphery of the insulating coating of the probe 34, and the leakage current is well collected there. or,
The cylindrical insertion portion 38 of the probe 34 is inserted into the cylindrical receiving portion of the input terminal 44.
When inserted into 64, the respective axes of the insertion part 38 and the receiving part 64 are aligned, and the axes of both contact bodies 52, 70 coaxial with them are further aligned. Therefore, the inner and outer peripheral walls of the two contact bodies 52, 70 can be widely and well contacted with each other, and the contact resistance can be reduced. Therefore, the leakage current collected in the current collector 50 is
It can be easily removed via 70 to the common potential line 76 of the circuit.

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

FIG. 1 is a partial vertical cross-sectional view showing a structure in the vicinity of a corresponding input terminal of a probe and an apparatus main body in a resistance meter having a detachable probe to which the present invention is applied. In the figure, 34 is a line probe, 36 is an insulating coating part in the middle, and 38 is an insertion part at the rear end. 40 is the main body of the resistance meter, 42 is its case, and 44 is a line terminal provided in the case. At the tip of the probe 34, there is a needle-like connecting portion that is electrically connected to the insertion portion 38 via the twisted wire 46 included in the insulating coating portion 36. Insert 38
Is a cylindrical metal fitting, and a plurality of slits 48 are formed along the longitudinal direction of the metal fitting so as to give elasticity from the center to the tip. Then, the cylindrical metal fitting 50 serving as a current collector is brought into close contact with the rear end surface of the insulating coating portion 36. Further, in the vicinity of the outer side near the tip of the insertion portion 38, the cylindrical metal fitting 52 as a contact body is separated and disposed coaxially. Moreover, the current collector 50 and the contact body 52 are connected by the conductor wire 54.

The vicinity of the connection between the insulating coating portion 36 and the insertion portion 38, including the current collector 50 and the like, is housed in an insulating case 56 and well fixed to facilitate handling of the probe 34. At that time, the insertion part 38
The longitudinal direction of the insulating coating portion 36 is appropriately selected with respect to the longitudinal direction of, and is made orthogonal, for example. The contact body 52 is an insulating case 56.
Fixed to. Further, the remaining insertion portion 38 and the contact body 52 are housed in a cylindrical insulating cover 58 attached to an insulating case 56.
This insulating cover 58 is also arranged coaxially, and its inner peripheral wall and the contact body
A constant space is formed between the outer peripheral wall of 52.

The line terminal 44 to which the line probe 34 is attached and detached is installed inside the cylindrical space 60 provided in the main body case 42. The inner peripheral wall of the space 60 is covered with an insulating cover 62, and in the center thereof, a cylindrical metal fitting which is a receiving portion into which the insertion portion 38 of the probe 34 is fitted.
There are 64. Moreover, the lower end of the cylindrical metal fitting 64 is closed, and the conducting wire 66 leading to the resistance value measuring circuit is connected thereto. Therefore, a cylindrical insulating strut 68 that supports the receiving portion 64 is arranged near the outside thereof, and a cylindrical metal fitting 70 is further arranged near the outside thereof as a contact body facing the contact body 52 of the probe 34. To do. The space 60, the receiving portion 64, the column 68, and the contact body 70 are coaxial with each other, and the probe is provided between the column 68 and the contact body 70.
The insulating cover of the probe 34 is provided between the space 72 in which the contact body 52 of 34 is fitted, and between the contact body 70 and the insulating cover 62 covering the inner peripheral wall of the space 60.
There are spaces 74 into which 58 fits. Moreover, prop 6
8, the contact body 70 and the like are fixed to the case 42.

The contact body 70 of the line terminal 44 is connected to the common potential line 76 of the circuit via the resistor 77. Further, a guard terminal 78 is provided on the main body case 42, and similarly connected to the common potential line 76. However, the guard terminal 78 is used when measuring the insulation resistance of the cable. In that case, use a bare wire as usual, and insulate the exposed end of the cable with the conductor protruding and the guard terminal.
Connect 78 to eliminate leakage currents that tend to flow from the wires to the insulation. The structure of the ground probe and the ground terminal provided on the device body 40 is the same as the conventional structure. That is, the ground probe is not provided with the current collector 50, the lead wire 54, and the contact body 52 of the line probe 34, and the ground terminal is not provided with the contact body 70 of the line terminal 44. Are the same respectively.

In order to measure the resistance of an object to be measured with an ohmmeter equipped with such a detachable probe, first insert the earth probe into the earth terminal and the line probe 34 into the line terminal 44 and attach them with one touch. Then, the insertion part of the ground probe fits into and contacts the receiving part of the ground terminal, and the device main body 40
Connect to the resistance measurement circuit of. In addition, the insertion portion 38 of the line probe 34 and the receiving portion 64 of the line terminal 44 also come into contact with each other, and the lead wire
Connect to the resistance measurement circuit through 66. Moreover, in the line probe 34, the contact body 52 is the contact body 70 of the line terminal 44.
The current collector 50 of the probe 34 connects to the common potential line 76 of the circuit for further contact with. Therefore, when the ground probe is connected to one end of the DUT and the line probe 34 is connected to the other end, the current flowing from the connection part of the ground probe to the DUT enters the connection part of the line probe 34, and the twisted wire 46,
It flows into the resistance value measuring circuit through the insertion portion 38, the receiving portion 64, the conductor 66 and the like. Further, the leakage current flowing on the insulating coating surface of the line probe 34 flows from the current collector 50 to the common potential line 76 through the conductor wire 54, the contact bodies 52 and 70, the resistor 77, and the like. Therefore, the leakage current can be removed only by inserting the line probe 34 into the input terminal 44 of the device body 40.

Moreover, the cylindrical current collector 50 adheres along the outer periphery of the insulating coating of the probe 34, and collects leakage current well there. or,
The cylindrical insertion portion 38 of the probe 34 is inserted into the cylindrical receiving portion of the input terminal 44.
When inserted into 64, the respective axes of the insertion portion 38 and the receiving portion 64 are aligned, and the axes of both cylindrical contact bodies 52 and 70 that are coaxial with them are further aligned, and one contact body 52 is Since it fits in the other contact body 70, the inner and outer peripheral walls of both contact bodies 52, 70 can be widely and well contacted, and the contact resistance can be reduced. The insulating cover 58 of the probe 34 fits into the space 74. Therefore, the leakage current collected in the current collector 50 is guided to the common potential line 76 of the circuit through both the contact bodies 52 and 70 and can be removed well.

After the measurement is completed, the line probe 34 should be
From the line terminal 44 of the
64, the contact bodies 52, 70 can be easily separated by separating them. The same applies to the insertion part of the ground probe and the receiving part of the ground terminal.

Effects of the Invention According to the present invention described above, a conduction path from the current collector to each contact body and the common potential line is immediately formed by inserting the probe into the input terminal of the apparatus body and mounting the probe. Therefore, the preparation work for the measurement does not take time, the leakage current is removed, and the resistance can be accurately measured.

Then, the leakage current is well collected in the cylindrical current collector, the contact resistance is reduced by bringing the inner and outer peripheral walls of the cylindrical contact bodies whose axes are aligned into contact with each other, and the leakage current is satisfactorily removed.
The resistance can be measured more accurately.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a structure in the vicinity of a corresponding input terminal of a probe and an apparatus main body in a resistance meter having a detachable probe to which the present invention is applied. FIG. 2 is a schematic explanatory view showing a resistance measurement state in a resistance meter equipped with a conventional detachable probe. 34 ... Probe, 36 ... Insulation coating part, 38 ... Insert part, 40
...... Main unit, 44 …… Input terminal, 50 …… Current collector, 52,70
…… Contact body, 64 …… Reception part, 76 …… Common potential line

Claims (2)

(57) [Scope of utility model registration request] 1. A detachable probe having a connecting portion at the front end, an inserting portion at the rear end and an insulating coating portion at the middle is provided in the apparatus main body, and the inserting portion of the probe is provided at an input terminal of the apparatus main body at the time of measurement. Also, in the ohmmeter that is used by inserting it into the receiving part connected to the resistance value measurement circuit, attach the current collector closely to the insulating coating surface of the probe, and place the contact body connected to the current collector near the insertion part. The contact body facing the contact body of the probe is placed apart from the input terminal of the device body in the vicinity of the receiving portion of the input terminal, and the contact body of the input terminal is connected to the common potential line of the circuit. An ohmmeter equipped with a detachable probe characterized in that 2. A probe insertion part, a current collector, and a contact body are respectively formed into a cylindrical shape, and the contact body is coaxially arranged outside the insertion part, and further, an input terminal receiving portion and a contact body of the apparatus main body. The resistance meter with a detachable probe according to claim 1, wherein the contact member is coaxially arranged outside the receiving portion.