JP7412922B2 - Method for evaluating withstand voltage characteristics of insulation materials and device for measuring withstand voltage characteristics - Google Patents

Description

The present invention relates to a method for evaluating withstand voltage characteristics of an insulating material and an apparatus for measuring withstand voltage characteristics.

A general withstand voltage characteristic test for insulation materials is known (JIS C2110). Further, Patent Document 1 discloses a method and a testing device for testing voltage resistance characteristics by applying a voltage between the two electrodes, which includes two electrodes that sandwich an insulating material and a spring that presses the electrodes. is disclosed (see Patent Document 1).

Japanese Patent Application Publication No. 2000-9789

For example, when insulating material is installed on equipment made of aluminum die-casting, if burrs remain on the equipment or foreign objects are present at the installation location, the burrs or foreign objects (hereinafter referred to as "burrs, etc.") may Pressure may concentrate in a narrow area of the insulating material and interfere with it, affecting the withstand voltage characteristics of the insulating material. However, with conventional testing methods and testing equipment, it has not been possible to measure or evaluate the withstand voltage characteristics when burrs or the like interfere with the insulating material.

The present invention aims to solve the above problems, and is capable of evaluating the withstand voltage characteristics of an insulating material assuming a situation where pressure caused by burrs etc. concentrates on a narrow range of the insulating material and interferes with the insulating material. An object of the present invention is to provide a characteristic evaluation method and a withstand voltage characteristic measuring device.

The present invention is a method for evaluating withstand voltage characteristics of an insulating material, in which an insulating material is sandwiched between a pair of electrodes and locally pressed, a thin part of the insulating material is formed between the electrodes, and a thin part of the insulating material is formed between the electrodes. This is a withstand voltage characteristic evaluation method that evaluates the withstand voltage characteristics of an insulating material by applying a voltage. Locally pressing means that the pressing force is concentrated in a narrow area of the insulating material.

According to the present invention, the insulating material is sandwiched between a pair of electrodes and pressed locally to form a thin part of the insulating material between the pair of electrodes, thereby simulating the part that is being interfered with by burrs etc. can be made. Furthermore, by applying a voltage between the pair of electrodes, it is possible to check whether there is dielectric breakdown in this thin portion. As a result, according to the present invention, withstand voltage characteristics can be evaluated assuming a situation where burrs or the like locally interfere with the insulating material.

Alternatively, at least one of the pair of electrodes may have a tip, and the tip may be pierced into an insulating material to form a thin portion between the tip and the other electrode. By piercing the insulating material with the tip, it is possible to intentionally damage the insulating material to form a thinner part, and the withstand voltage characteristics in that state can be evaluated.

In addition, by placing a foreign object between at least one electrode of a pair of electrodes and the insulating material, and sandwiching the foreign object and the insulating material between the pair of electrodes, a thin part can be formed between the foreign object and the other electrode. may be formed. By locally pressing the insulating material with a foreign object rather than the electrode itself, a thinner part of the insulating material can be formed, and the withstand voltage characteristics in that state can be evaluated.

Alternatively, the withstand voltage characteristics of the insulating material may be evaluated by applying a voltage between the electrodes while changing the thickness of the thin portion of the insulating material. For example, the thickness of the thin portion can be changed by changing the piercing depth of the tip or by changing the size of the foreign object. Then, by applying an appropriate voltage while changing the thickness of the thin portion , it is possible to evaluate the thickness at which dielectric breakdown occurs.

Further, the voltage resistance characteristics of the insulating material may be evaluated while changing the voltage applied between the electrodes. By changing the voltage applied between the electrodes, the voltage at which dielectric breakdown occurs can be evaluated.

Further, the withstand voltage characteristics of the insulating material may be evaluated while changing both the thickness of the thin portion of the insulating material and the voltage applied between the electrodes. By evaluating the withstand voltage characteristics of an insulating material while changing both the thickness of the thin part and the voltage applied between the electrodes, we can determine the causal relationship between the thickness of the thin part and the voltage applied between the electrodes and dielectric breakdown. can be evaluated.

The present invention also provides a withstand voltage characteristic measuring device for evaluating the withstand voltage characteristics of an insulating material, in which a pair of electrodes are moved in opposing directions, and a pair of electrodes are moved in opposite directions, and a An inter-electrode distance adjustment section that can adjust the distance between electrodes, a voltage application section that applies voltage between a pair of electrodes, and an index value measurement section that measures an index value for evaluating the presence or absence of dielectric breakdown of an insulating material. It is equipped with.

In the present invention, by adjusting the distance between a pair of electrodes with the insulating material sandwiched therebetween using the inter-electrode distance adjustment section, the insulating material can be locally pressed to form a thin portion. Furthermore, by applying a voltage between the pair of electrodes using the voltage application section, it is possible to check whether or not there is dielectric breakdown in this thin portion. As a result, according to the present invention, withstand voltage characteristics can be evaluated assuming a situation where burrs or the like locally interfere with the insulating material.

Further, the device may further include a tip portion provided on at least one of the pair of electrodes and disposed toward the other electrode. By adjusting the distance between the pair of electrodes using the inter-electrode distance adjusting section, it is possible to pierce the tip into the insulating material and form a thin portion between the tip and the other electrode. As a result, it is possible to evaluate the withstand voltage characteristics in a state where the insulating material is intentionally damaged to form a thin portion.

Further, the voltage application unit may be able to change the voltage applied between the pair of electrodes. By changing the voltage applied between the electrodes, the voltage at which dielectric breakdown occurs can be evaluated.

Further, the pair of electrodes are arranged to face each other in the vertical direction, and include an elevating part that holds at least one of the pair of electrodes, and a column part that supports the elevating part so that it can rise and fall. The distance adjustment section includes a shaft section that is fixed to the elevating section and extends in the vertical direction, and a base that supports the shaft section movably in the vertical direction and can adjust the amount of vertical movement of the shaft section. It may also include a structural part. By adjusting the amount of vertical movement of the shaft portion using the basic structure, the distance between the pair of electrodes can be easily adjusted by raising and lowering the elevating portion.

According to the present invention, withstand voltage characteristics can be evaluated assuming a situation where burrs or the like locally interfere with the insulating material.

FIG. 1 is a side view of a withstand voltage characteristic measuring device according to an embodiment of the present invention. FIG. 3 is an enlarged view schematically showing the relationship between an insulating material and an electrode installed in the withstand voltage characteristic measuring device according to the embodiment. FIG. 3 is an enlarged view showing a side surface of an electrode. Modifications of the electrode are shown, (a) is a side view of the first modification, (b) is a side view of the second modification, and (c) is the third modification. It is a side view which shows an example, and (d) is a side view which shows a 4th modification. Modifications of the electrodes are shown, with (a) being a side view showing a fifth modification, and (b) being a sectional view taken along line bb in (a). FIG. 7 is a side view of a withstand voltage characteristic measuring device according to another embodiment. FIG. 7 is an enlarged view schematically showing the relationship between an insulating material and an electrode installed in a withstand voltage characteristic measuring device according to another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a withstand voltage characteristic measuring device and a withstand voltage characteristic evaluation method according to the present invention will be described in detail with reference to the drawings.

First, with reference to FIGS. 1 and 2, a withstand voltage characteristic measuring device 1 according to an embodiment will be described. The withstand voltage characteristic measuring device 1 is a device that measures an index value for evaluating the presence or absence of dielectric breakdown of an electrical insulating material, and based on the index value measured by the withstanding voltage characteristic measuring device 1, It is possible to evaluate the withstand voltage characteristics of Here, this index value is, for example, a voltage value, a current value, or a resistance value, and may be a composite value thereof. In addition, withstand voltage characteristics broadly include properties related to withstand voltage (also referred to as dielectric strength). Therefore, it includes not only the withstand voltage but also the correlation between the withstand voltage and the thickness of the insulating material, insulation resistance, etc.

The withstand voltage characteristic measuring device 1 measures a pair of electrodes 3 and 4 arranged facing each other, and at least one electrode (for example, electrode 3) of the pair of electrodes 3 and 4, in a direction D in which the electrodes 3 and 4 face each other. The micrometer 6 includes an elevating section 10 that moves the elevating section 10 and a micrometer 6 that moves the elevating section 10 and maintains a predetermined distance between the pair of electrodes 3 and 4. An insulating sheet W (an example of an insulating material) to be measured is arranged between the pair of electrodes 3 and 4. The micrometer 6 is an example of an inter-electrode distance adjusting section.

The pair of electrodes 3 and 4 according to this embodiment are arranged in an up-down direction (for example, a vertical direction), which is an example of a facing direction D. The lower electrode 4 is fixed at a fixed position, and the upper electrode 3 is movable in the vertical direction. Here, the opposing direction D means a direction in which the pair of electrodes 3 and 4 relatively approach and separate. Therefore, the pair of electrodes 3 and 4 is not limited to the vertical direction, but may be arranged laterally (for example, horizontally) or in an oblique direction tilted from the vertically or horizontally. Further, in this embodiment, an example will be described in which the upper electrode 3 is movable, but the lower electrode 4 may be movable, and both the electrode 3 and the electrode 4 may be moved in opposite directions. It may be possible to move to D.

The lower electrode (hereinafter referred to as "fixed electrode") 4 has a flat plate shape. The fixed electrode 4 is fixed to the tips of a plurality of pedestals 8, and the pedestals 8 are erected from the base plate 7. The pillar portion 8 or base plate 7 that supports the fixed electrode 4 has electrical insulation properties. Of both surfaces of the fixed electrode 4, an insulating sheet W to be measured is placed on the surface opposite to the pillar section 8.

Although the shape, thickness, etc. of the insulating sheet W can be selected as appropriate, the thickness of the insulating sheet W according to this embodiment may be, for example, 0.1 mm or more. Further, the thickness of the insulating sheet W may be 5 mm or less, and may be further thinner than 1 mm. Further, the insulating sheet W may be a flexible insulating sheet. Examples of flexible insulating sheets include resin sheets. The resin sheet may be either a resin sheet made of a thermosetting resin or a resin sheet made of a thermoplastic resin. Further, the resin sheet may be filled with filler. Examples of the filler include inorganic particles, and examples of the inorganic particles include carbides, nitrides, oxides, hydroxides, and carbon-based materials. An example of the resin sheet is a heat dissipation sheet containing boron nitride.

A plurality of holes Wa are formed in the insulating sheet W. A plurality of female screws 4a corresponding to a plurality of holes Wa of the insulating sheet W are formed in the fixed electrode 4 that comes into contact with the insulating sheet W. A metal (conductive) bolt 9 is screwed into the female thread 4a of the fixed electrode 4 from below, and the shaft portion of the bolt 9 protruding from the fixed electrode 4 is passed through the hole Wa of the insulating sheet W, and the insulating sheet Position W.

The upper electrode (hereinafter referred to as "movable electrode") 3 is held by a lifting section 10. The movable electrode 3 (see FIG. 3) includes a cylindrical knob 31 with a non-slip finish, a needle 32 protruding from one end of the knob 31, and a needle 32 protruding from the other end of the knob 31. A protruding connecting shaft portion 33 is provided. The tip of the needle portion 32 is an acutely pointed tip portion 32a. The connecting shaft portion 33 is provided with a male thread.

The movable electrode 3 may have any shape as long as it can press the insulating sheet W locally. Locally pressing means that the pressing force is concentrated in a narrow range of the insulating sheet W, that is, it means that the pressing force is pressed by contacting only a part of the insulating sheet W, not the entire surface. For example, it means contacting and pressing within a range of about 5 mm ² , which may be 2 mm ² or less, 0.5 mm ² or less, or 0.1 mm ² or less.

The movable electrode 3 can take various forms. For example, as shown in FIG. 4(a), as a first modification, a movable electrode 3A has a cylindrical body portion 34 whose diameter is expanded at the tip and a conical tip portion 32b is provided at the tip. It may be. In addition, as shown in FIG. 4B, as a second modification, a movable electrode is provided in which the tip of the cylindrical body portion 34 is expanded in diameter and a convex curved surface 32c is provided at the tip of the body portion 34. It may be 3B. In addition, as shown in FIG. 4C, as a third modification, the diameter of the tip of the cylindrical body portion 34 is expanded, and a plurality of tip portions 32d are provided along the circumference of the tip. The movable electrode 3C may be a fixed movable electrode 3C. In addition, as shown in FIG. 4(d), as a fourth modification, the tip of the cylindrical body portion 34 is expanded in diameter, the tip is tapered and reduced in diameter, and a plurality of The movable electrode 3D may be provided with a pointed end 32e.

Further, in the present embodiment and the above-mentioned Modifications 1, 3, and 4, the pointed end portions 32b, 32d, and 32e have point-shaped points, but for example, FIGS. As shown in FIG. 2, as a fifth modification, a movable electrode 3E may be provided with a linear pointed end 32f like a knife.

As shown in FIG. 1, the elevating section 10 includes a plurality of guide columns 11 (column sections) erected from the base plate 7, an elevating plate 5 that can be raised and lowered along the guide columns 11, and the elevating plate 5. A support plate 12 that moves up and down. A fixed plate 14 fixed to the guide column 11 is arranged above the elevating area (movable area) of the elevating plate 5. The fixed plate 14 and the lifting plate 5 are connected by an elastic body 15, such as a coil spring, that supports lifting of the lifting plate 5.

The movable electrode 3 is arranged such that the pointed end 32a of the needle portion 32 faces downward and the connecting shaft portion 33 faces upward, and the connecting shaft portion 33 is screwed and fixed to the support plate 12. The support plate 12 is fixed to the lifting plate 5 via a rod member 13 having electrical insulation properties. The elevating plate 5 is attached to the guide column 11 via a bearing portion 51 so as to be movable up and down.

The micrometer 6 includes a micrometer head 6a (basic structure) fixed to a fixed plate 14, and a spindle 6b (shaft) extending vertically through the fixed plate 14. The lower end of the spindle 6b is fixed to the lifting plate 5, and the upper end is accommodated in the micrometer head 6a. The micrometer head 6a supports the spindle 6b so as to be movable in the vertical direction using a screw mechanism, and can adjust the amount of vertical movement of the spindle 6b by rotating the micrometer head 6a.

The withstand voltage characteristic measuring device 1 includes a voltage application measuring section 20 . The voltage application measurement unit 20 has a voltage application function of applying a voltage between the fixed electrode 4 and the movable electrode 3 (between the pair of electrodes 3 and 4), and measures an index value for evaluating the presence or absence of dielectric breakdown of the insulating material. It also has an index value measurement function. This index value is, for example, a voltage value or resistance value between a pair of electrodes 3 and 4, a current value flowing between a pair of electrodes 3 and 4, and the like. By checking this index value, it is confirmed whether or not there is current flowing between the pair of electrodes 3 and 4. The energized state means a state where dielectric breakdown has occurred. The voltage up to the limit at which dielectric breakdown occurs is the "withstanding voltage." Furthermore, by measuring the resistance value between the pair of electrodes 3 and 4, it is possible to evaluate the resistance value (insulation resistance) between the pair of electrodes 3 and 4, which should not be electrically connected.

In order to evaluate the withstand voltage characteristics, it is necessary to apply a high voltage to the insulating sheet W, and therefore the test circuit of the voltage application and measurement section 20 is a high voltage output circuit. As the voltage application and measurement section 20, a commercially available withstand voltage testing device, insulation resistance testing device, etc. can be used as appropriate.

The high voltage output circuit of the voltage application and measurement section 20 is electrically connected to a bolt 9 that connects the insulating sheet W and the fixed electrode 4, and is also attached to a support plate 12 to which the movable electrode 3 is fixed. It is electrically connected to a metal (electrically conductable) bolt 12a.

Next, a method for evaluating withstand voltage characteristics according to this embodiment will be explained. First, an insulating sheet W is installed between the movable electrode 3 and the fixed electrode 4 (between the pair of electrodes 3 and 4) of the withstand voltage characteristic measuring device 1 (insulating material installation step). In this embodiment, the insulating sheet W is placed on the fixed electrode 4 and fixed by screwing the bolt 9 together. Next, a predetermined voltage is applied between the pair of electrodes 3 and 4, and it is confirmed that no dielectric breakdown has occurred with the movable electrode 3 not interfering with the insulating sheet W (initial confirmation step).

Next, a withstand voltage characteristic evaluation step is performed. As the withstand voltage characteristic evaluation process, for example, the following three evaluation methods can be implemented. Each method will be explained in detail.

In the first evaluation method, the movable electrode 3 is lowered in stages to pierce the insulating sheet W with the tip 32a of the movable electrode 3. The distance from the tip 32a of the movable electrode 3 to the fixed electrode 4 is a thinner part (hereinafter referred to as "thinner part") d (see FIG. 2) of the insulating sheet W, and as the stage progresses, the thinner part becomes smaller. The thickness of d becomes thinner. At each stage, a constant high voltage is applied, and the energization state is checked to see if there is any dielectric breakdown. When dielectric breakdown occurs, the thickness of the thin portion d at that stage is evaluated as the limit thickness at which dielectric breakdown occurs. Note that the thickness limit at which dielectric breakdown occurs (an example of withstand voltage characteristics) may be evaluated by continuously changing the thin portion d while a constant voltage is applied.

In the second evaluation method, the tip portion 32a of the movable electrode 3 is pierced into the insulating sheet W, and the movable electrode 3 is lowered until the thickness of the thin portion d reaches a predetermined depth as a reference. In this state, the magnitude of the applied voltage is changed stepwise without changing the thickness of the thin portion d. At each stage, check the current status and check for insulation breakdown. When dielectric breakdown occurs, the voltage at that stage is evaluated as a withstand voltage (an example of withstand voltage characteristics). Note that the withstand voltage may be evaluated by continuously changing the applied voltage.

The third evaluation method is a combination of the first evaluation method and the second evaluation method. Specifically, the thin portion d is changed stepwise, and at each step, a plurality of different voltages are applied, and the energization state is checked to see if there is any dielectric breakdown. According to this third evaluation method, it is possible to evaluate the correlation between the thickness of the thin portion d that causes dielectric breakdown and the voltage applied between the pair of electrodes 3 and 4 (an example of withstand voltage characteristics).

Next, with reference to FIGS. 6 and 7, a withstand voltage characteristic measuring device 1A and a withstand voltage characteristic evaluation method according to a second embodiment will be described. Note that the withstand voltage characteristic measuring device 1A according to the second embodiment includes the same elements and structure as the withstanding voltage characteristic measuring device 1 according to the first embodiment. Therefore, the following description will focus on the differences, and common elements and structures will be designated by the same reference numerals and detailed descriptions will be omitted.

The movable electrode 30 is, for example, integrally or indirectly fixed to the support plate 12. The movable electrode 30 is capable of supplying electricity to the support plate 12 . The movable electrode 30 includes a contact surface 30a that can contact the insulating sheet W over a wide area of at least 10 cm ² or more. When forming the thin portion d using the withstand voltage characteristic measuring device 1A according to the present embodiment, a conductive foreign substance F is first placed between the movable electrode 30 and the insulating sheet W. Then, the foreign object F and the insulating sheet W are sandwiched between the movable electrode 30 and the fixed electrode 4, and as a result, a thin portion d is formed between the foreign object F and the fixed electrode 4.

When carrying out the withstand voltage characteristic evaluation method using the withstand voltage characteristic measuring device 1A according to the second embodiment, a constant voltage is applied while holding foreign objects F of gradually different shapes and sizes in the energized state. By confirming this, it is possible to implement a withstand voltage characteristic evaluation method similar to the first evaluation method described above. In addition, by checking the energization state while changing the magnitude of the applied voltage with a foreign object F of a certain size sandwiched between them, it is possible to carry out a withstand voltage characteristic evaluation method similar to the second evaluation method described above. . In addition, by checking the energization state while holding foreign objects F of different shapes and sizes step by step, and by changing the magnitude of the voltage applied at each step, the withstand voltage similar to the third evaluation method described above can be achieved. Ability to perform characterization methods. Note that each of the above steps may be performed continuously.

Next, the functions and effects of the above-described withstand voltage characteristic measuring devices 1 and 1A and withstand voltage characteristic evaluation method will be explained. For example, when using an insulating sheet W (insulating material) attached to an actual machine, if there is metal foreign matter mixed in at the attachment point or burrs from manufacturing remain, the insulation properties of the insulating sheet W may be affected. This can sometimes lead to insulation failure. However, increasing the thickness of the insulating material to avoid insulation defects is detrimental to compactness, so it is not preferable to simply increase the thickness of the insulating material to ensure insulation.

On the other hand, according to the withstand voltage characteristic evaluation method using the withstand voltage characteristic measuring devices 1 and 1A, the insulating sheet W is sandwiched between the movable electrodes 3 and 30 and the fixed electrode 4 and pressed locally. By forming the thin part d of the insulating sheet W between the fixed electrode 30 and the fixed electrode 4, it is possible to create a simulated part that is subject to interference from burrs or the like. Furthermore, by applying a voltage between the movable electrodes 3, 30 and the fixed electrode 4, it is possible to check whether there is dielectric breakdown in the thin portion d. That is, according to this withstand voltage characteristic evaluation method, the withstand voltage characteristics can be evaluated assuming a situation where burrs or the like locally interfere with the insulating sheet W. As a result, it becomes possible to quantitatively evaluate the withstand voltage characteristics of the insulating sheet W under the influence of burrs and foreign matter without attaching the insulating sheet W to an actual machine.

Further, in the case of a thin insulating sheet W having a thickness of 1 mm or less, problems due to burrs or the like, for example, problems such as damage to the insulating sheet W and conduction of electricity are likely to occur. According to the evaluation method and evaluation apparatus of this embodiment, even a thin insulating sheet W can be evaluated. In addition, if the insulating sheet W is flexible, problems such as the insulating sheet W being damaged and causing current to flow, or the thickness of the insulating sheet W becoming locally reduced due to deformation are likely to occur, resulting in a decrease in insulation properties. . According to the evaluation method and evaluation apparatus of this embodiment, a flexible insulating sheet W can be evaluated.

Further, in the withstand voltage characteristic measuring device 1 according to the first embodiment described above, the thin portion d is formed by piercing the tip portion 32a of the movable electrode 3 into the insulating sheet W. That is, the thin portion d can be formed by intentionally scratching the insulating sheet W, and the withstand voltage characteristics in that state can be evaluated. In particular, in the withstand voltage characteristic measuring device 1, the depth at which the tip portion 32a of the movable electrode 3 is pierced into the insulating sheet W can be easily adjusted as appropriate, so that it is easy to quantitatively evaluate the withstand voltage characteristics.

In addition, in the withstand voltage characteristic measuring device 1A according to the second embodiment described above, by sandwiching the foreign matter F and the insulating sheet W between the movable electrode 30 and the fixed electrode 4, a thin film is formed between the foreign matter F and the fixed electrode 4. It forms part d. That is, by locally pressing the insulating sheet W with the foreign matter F, the thin portion d can be formed, and the withstand voltage characteristics in that state can be evaluated. In particular, in the withstand voltage characteristic measuring device 1A, since the thin part d is formed using the foreign matter F, if the shape and dimensions of the foreign matter that may actually occur can be identified, the withstand voltage characteristics due to the foreign matter can be determined. It becomes easier to appropriately assess the impact on

Further, according to the first evaluation method described above, the thickness of the thin portion d can be changed by changing the piercing depth of the pointed end 32a or by changing the size of the foreign object F. Then, by applying an appropriate voltage while changing the thickness of the thin portion d, it is possible to evaluate the thickness at which dielectric breakdown occurs.

Furthermore, according to the second evaluation method described above, the withstand voltage characteristics of the insulating material are evaluated while changing the voltage applied between the movable electrodes 3, 30 and the fixed electrode 4. As a result, it is possible to evaluate the voltage at which dielectric breakdown occurs while changing the voltage applied between the movable electrodes 3, 30 and the fixed electrode 4.

Further, according to the third evaluation method described above, the withstand voltage characteristics of the insulating sheet W are evaluated while changing both the thickness of the thin portion d and the voltage applied between the movable electrodes 3, 30 and the fixed electrode 4. By doing so, it is possible to evaluate the causal relationship between the thin portion d, the applied voltage, and dielectric breakdown.

Furthermore, in the withstand voltage characteristic measuring apparatuses 1 and 1A according to each of the embodiments described above, the amount of vertical movement of the spindle 6b can be adjusted by operating the micrometer head 6a (basic structure) of the micrometer 6. By adjusting the amount of vertical movement of the spindle 6b, the distance between the movable electrodes 3, 30 and the fixed electrode 4 can be easily adjusted by raising and lowering the lifting plate 5. As a result, the thickness of the thin portion d can be easily adjusted.

Although the withstand voltage characteristic measuring device and the withstand voltage evaluation method have been described above based on each embodiment, the present invention is not limited only to these embodiments. For example, this withstand voltage characteristic evaluation method can also be implemented using a device other than the withstand voltage characteristic measuring devices 1 and 1A according to each of the embodiments described above. Further, the withstand voltage characteristic measuring devices 1 and 1A according to each embodiment include a voltage application measurement section 20 that has both a voltage application function and an index value measurement function. It can also be performed by an independent device separate from the function.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples. In this example, a withstand voltage characteristic evaluation method was carried out using a device corresponding to the withstand voltage characteristic measuring device according to the first embodiment described above. As the insulating material, an insulating sheet (insulating sheet made of a silicone resin composition containing 60% by volume of boron nitride) with a thickness of 0.2 mm was used.

(First evaluation method)
First, the first evaluation method will be explained. Specifically, the state before the movable electrode interfered with the insulating sheet was defined as the initial state, and in this state, a voltage of DC 1.2 kV was applied for 60 seconds. The voltage was applied about 5 times (n1 to n5) under the same conditions, and the evaluation was made as OK if no current was confirmed, and NG if electricity was confirmed and dielectric breakdown was evaluated. In the initial state, all of n1 to n5 were OK.

Next, the movable electrode was pierced into the insulating sheet, the thickness of the thin part was set to 0.19 mm, and a DC voltage of 1.2 kV was applied for 60 seconds in the same manner as above. The voltage was applied about 5 times (n1 to n5) under the same conditions, and the evaluation was made as OK if no current was confirmed, and NG if electricity was confirmed and dielectric breakdown was evaluated. In the initial state, all of n1 to n5 were OK.

Similarly, the thickness of the thin part was changed to become smaller stepwise, and voltage was applied five times (n1 to n5) under the same conditions each time, and the presence or absence of dielectric breakdown was evaluated. Specifically, the thickness of the thin part was decreased step by step by 0.01 mm, and at each step, voltage was applied five times (n1 to n5) under the same conditions to evaluate the presence or absence of dielectric breakdown. (See Table 1). As a result, it was confirmed that dielectric breakdown occurred when the thickness of the thin portion was 0.01 mm.

Although not shown in Table 1, when the first evaluation method was performed on an insulating sheet with low resistance to burrs etc. (an insulating sheet made of a silicone resin composition containing 70% by volume of alumina), Dielectric breakdown occurred at 0.06 mm. In other words, dielectric breakdown occurred in a state where the thickness of the thin part was greater in an insulating sheet with lower resistance to burrs etc. than in an insulating sheet made of a silicone resin composition containing 60% by volume of boron nitride. . As a result, it was confirmed that the resistance to burrs etc. could be appropriately evaluated using the first evaluation method.

(Second evaluation method)
Next, the second evaluation method will be explained. The thickness of the thin part was set to 0.07 mm, and in this state, the applied voltage was increased from 0 kV until dielectric breakdown occurred. In this case, energization was measured at 9.5 kV, and it was confirmed that dielectric breakdown occurred (see Table 2). In this evaluation, an insulating sheet similar to the insulating sheet used in the first evaluation method (an insulating sheet made of a silicone resin composition containing 60% by volume of boron nitride) was used.

Although not shown in Table 2, the second evaluation method was also applied to an insulating sheet (an insulating sheet made of a silicone resin composition containing 70% by volume of alumina) having low resistance to burrs and the like. For an insulating sheet with low resistance to burrs, etc., if the thickness of the thin part is 0.07 mm and the applied voltage is increased from 0 kV until dielectric breakdown occurs in this state, energization is measured at a voltage lower than 9.5 kV. It was confirmed that dielectric breakdown occurred.

(Third evaluation method)
Next, the third evaluation method will be explained. Similarly to the first evaluation method described above, the thickness of the thin part was adjusted to decrease stepwise by 0.01 mm from the initial state, and at each step, the applied voltage was adjusted from 0 kV until dielectric breakdown occurred. The pressure was increased (see Table 3).

In this third evaluation method, when the voltage at which the desired withstand voltage characteristics were obtained was set to 10 kV, it was confirmed that the desired withstand voltage characteristics were obtained at least until the thickness of the thin portion reached 0.08 mm. Further, when the thickness of the thin part is 0.07 mm, the voltage at which dielectric breakdown occurs is 9.5 kV, and when the thickness of the thin part is 0.06 mm, the voltage at which dielectric breakdown occurs is 7.1 kV, When the thickness of the thin part is 0.05 mm, the voltage at which dielectric breakdown occurs is 6.9 kV; when the thickness of the thin part is 0.04 mm, the voltage at which dielectric breakdown occurs is 6.3 kV; When the thickness of the thin part is 0.03 mm, the voltage at which dielectric breakdown occurs is 5.5 kV, and when the thickness of the thin part is 0.02 mm, the voltage at which dielectric breakdown occurs is 5.6 kV, and the thickness of the thin part When the distance was 0.01 mm, the voltage at which dielectric breakdown occurred was 2.8 kV. In other words, by the third evaluation method, it was possible to evaluate the correlation between the thickness of the thin portion, the applied voltage, and dielectric breakdown.

DESCRIPTION OF SYMBOLS 1, 1A...Withstand voltage characteristic measuring device, 3...Movable electrode, 32a...Tip part, 4...Fixed electrode, 6...Micrometer (inter-electrode distance adjustment part), 6a...Micrometer head (basic structure part), 6b... Spindle (shaft part), 10... Lifting part, 11... Guide part (column part), 20... Voltage application measurement part (voltage application part, index value measurement part), d... Thin thickness part, F... Foreign object, D... Opposing direction , W...Insulating sheet (insulating material).

Claims (7)

A method for evaluating withstand voltage characteristics of an insulating material, the method comprising:
The insulating material is sandwiched between a pair of electrodes and pressed locally,
forming a thin portion of the insulating material between the electrodes;
placing a foreign object between at least one of the pair of electrodes and the insulating material;
forming the thin part between the foreign substance and the other electrode by sandwiching the foreign substance and the insulating material between the pair of electrodes;
A method for evaluating withstand voltage characteristics of an insulating material, the method comprising applying a voltage between the electrodes to evaluate the withstand voltage characteristics of the insulating material. 2. The withstand voltage characteristic evaluation method according to claim 1, wherein the withstand voltage characteristics of the insulating material are evaluated by applying a voltage between the electrodes while changing the thickness of the thin portion . The withstand voltage characteristic evaluation method according to claim 1, wherein the withstand voltage characteristics of the insulating material are evaluated while changing the voltage applied between the electrodes. 2. The method for evaluating withstand voltage characteristics according to claim 1, wherein the withstand voltage characteristics of the insulating material are evaluated while changing both the thickness of the thin portion and the voltage applied between the electrodes. A withstand voltage characteristic measuring device for evaluating the withstand voltage characteristics of an insulating material,
A pair of electrodes arranged to face each other in the vertical direction ;
an inter-electrode distance adjustment unit that can move the pair of electrodes in opposing directions and adjust the distance between the pair of electrodes with the insulating material sandwiched therebetween;
a voltage applying section that applies a voltage between the pair of electrodes;
an index value measurement unit that measures an index value for evaluating the presence or absence of dielectric breakdown of the insulating material;
an elevating part that holds at least one of the pair of electrodes;
A column part that supports the elevating part so that it can be raised and lowered,
The inter-electrode distance adjustment section is
a shaft part fixed to the elevating part and extending in the vertical direction;
A withstand voltage characteristic measuring device , comprising: a basic structure part that supports the shaft part so as to be movable in the vertical direction and can adjust the amount of movement of the shaft part in the vertical direction . 6. The withstand voltage characteristic measuring device according to claim 5, further comprising a tip portion provided on at least one of the pair of electrodes and disposed toward the other electrode. 6. The withstand voltage characteristic measuring device according to claim 5, wherein the voltage applying section is capable of changing the voltage applied between the pair of electrodes.

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