JPH11329525A - Contact device - Google Patents

Abstract

(57) [Problem] To provide a contact device capable of increasing the current carrying capacity without increasing the size. SOLUTION: A groove 17 whose cross section is expanded at a predetermined angle γ is formed at a position where an arc-shaped energizing contact portion 23 of a contact piece 25 on one of outer circumferences of both conductors 15 and 20 contacts. The angle θ formed between the two points in contact with the side wall of the groove 17 is set to be equal to or greater than 120 ° and less than 180 °.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact device used for a current-carrying portion of an electric device, and more particularly to a structure capable of flowing a large current without increasing the size.

[0002]

2. Description of the Related Art FIG.
It is sectional drawing which shows the conventional contactor apparatus shown by patent publication 7. In the figure, 1 is a first conductor, 2 is a small-diameter portion as a contact portion formed at an end of the first conductor 1, 3 is a second conductor arranged opposite to the first conductor 1, 4 is a small-diameter portion as a contact portion formed at the end of the second conductor 3, and 5 is a first portion.
A holding plate arranged at an end of the conductor 1 having a predetermined diameter;
Reference numeral 6 denotes a bolt for fixing the holding plate 5 to the first conductor 1, 7 denotes a plurality of contact pieces arranged to engage with the holding plate 5 at predetermined positions over the outer circumferences of the small diameter portions 2, 4; Are contact portions formed at both ends of the contact piece 7 and in contact with the small diameter portions 2 and 4,

[0003] Reference numeral 9 denotes a plurality of garter springs which are arranged on the outer periphery of each contact piece 7 and press each contact portion 8, 8 against each small diameter portion 2, 4 via each contact piece 7; Each contact piece 7 is formed to be shorter than the outer circumference and is prevented from falling down by the pressing plate 5. And the tulip contact 1 in which a plurality of contact pieces 7 are radially arranged in the above 5, 7 to 9
0 is formed. Reference numeral 11 denotes a shield arranged to cover the tulip contact 10 to reduce an electric field, 12 denotes a leaf spring disposed inside the shield 10 and presses a predetermined contact piece 7, and 13 denotes a leaf spring inside the shield 11 between the predetermined contact pieces 7. Is a guide plate arranged so as to be interposed between the guide plates.

[0004] The contact device configured as described above has a first
Small-diameter portions 2 of the conductor 1 and the second conductor 3
A plurality of contact pieces 7 are pressed against each other by a tulip contact 10 bundled by a garter spring 9, and the small-diameter portions 2 and 4 are connected by the contact portions 8, respectively. A force (contact force) for pressing the parts 8, 8 against the small diameter parts 2, 4 is applied. Such a tulip contact 10
It is also used as a connection point of a conductor of a gas insulated switchgear, and also as a current-carrying part of a movable contact such as a circuit breaker or a disconnector.

[0005]

Since the conventional contact device is configured as described above, if a contact device for a large current is required, it is necessary to reduce the contact resistance and suppress heat generation. Since it is necessary to increase the energizing area and the contact area of the contact piece 7 and increase the number of the contact pieces 7, the number of the garter springs 9 must also increase with the increase of the contact pieces 7. There is a problem that the slave device becomes large and expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an inexpensive contact device capable of flowing a large current without increasing the size of the device. .

[0007]

According to a first aspect of the present invention, there is provided a contact device in which a first conductor on a fixed side forming an electric path, and the first conductor are opposed to each other at a predetermined interval. The second conductor on the movable side to be arranged, a plurality of contact pieces that are arranged radially in contact with the outer circumferences of both conductors across the two conductors, and the energizing contact portions are formed in an arc shape, and each contact piece. In a contact device provided with a spring for applying a contact force by pressing against each conductor, a groove whose cross-sectional shape is expanded at a predetermined angle at a position where the energized contact portion on the outer periphery of one of the two conductors contacts. And the angle at which the center of the arc of the energizing contact portion and the two points at which the energizing contact portion contacts the side wall of the groove is 120 ° or more and less than 180 °. .

In the contactor device according to a second aspect of the present invention, the first conductor on the fixed side forming the electric circuit, and the movable portion whose end is opposed to the first conductor at a predetermined interval. The second conductor on the side, a plurality of contact pieces radially arranged in contact with the outer periphery of both conductors across the two conductors, and a spring for applying a contact force by pressing each contact piece against each conductor. In the contactor device provided, a current-carrying contact portion having a cross-sectional shape protruding in an arc shape is formed on the outer periphery of one of the two conductors, and is expanded at a predetermined angle at a position where the contact piece comes into contact with the current-carrying contact portion. The angle formed between the center of the arc of the current-carrying contact portion and the two points where the current-carrying contact portion contacts the side wall of the groove is set to 120 ° or more and less than 180 °. Things.

Further, in the contact device according to claim 3 of the present invention, the first conductor on the fixed side forming the electric path, and the movable member whose end is opposed to the first conductor at a predetermined interval. The second conductor on the side, a plurality of contact pieces that are radially arranged in contact with the outer circumferences of the two conductors so as to be in contact with the outer circumferences of the two conductors between the two conductors, and that the current-carrying contact portions are formed in an arc shape; In a contact device provided with a spring for applying a contact force by pressing and contacting, a cross-sectional shape of the contact piece having a radius of curvature larger than the arc-shaped radius of curvature of a contact piece at a position where an energized contact portion on the outer periphery of one of the conductors contacts the contact device. A groove is formed.

Further, in the contact device according to claim 4 of the present invention, the first conductor on the fixed side forming the electric circuit, and the movable portion whose end is opposed to the first conductor at a predetermined interval. The second conductor on the side, a plurality of contact pieces radially arranged in contact with the outer periphery of both conductors across the two conductors, and a spring for applying a contact force by pressing each contact piece against each conductor. In the contactor device provided with, a current-carrying contact portion having a cross-sectional shape protruding in an arc shape having a predetermined radius of curvature is formed on an outer periphery of one of the two conductors, and a current-carrying contact is formed at a position where the contact piece comes into contact with the current-carrying contact portion of the contact piece. A groove having a radius of curvature larger than the radius of curvature of the portion is formed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing a configuration of a contact device according to Embodiment 1 of the present invention,
FIG. 2 is a side sectional view showing the configuration of the contact device of FIG. 1, and FIG.
3 is an enlarged view showing a contact portion in the contact device of FIG. 1, and FIG. 4 is an enlarged view showing a configuration of the contact portion of the contact device of FIG. 1 which is different from FIG.

In each of the drawings, reference numeral 15 denotes a fixed-side first conductor forming an electric path, 16 denotes a small-diameter portion formed at an end of the first conductor 15, and 17 denotes a cross-sectional shape formed on the outer periphery of the small-diameter portion 16. Is a groove as a contact portion expanded at an angle to be described later, 18 is a holding plate arranged at the end of the small diameter portion 16, and 19 is a bolt for fixing the holding plate 18.

Reference numeral 20 denotes a movable-side second conductor arranged opposite to the first conductor 15, reference numeral 21 denotes a small-diameter portion serving as a contact portion formed at an end of the second conductor 20, and reference numeral 22 denotes a predetermined portion. At the position, it is engaged with the outer periphery of the holding plate 18 and both ends are provided with the small diameter portions 16, 2.
A plurality of contact piece bodies radially arranged over one, 23
24 is a current-carrying contact portion formed in an arc shape with a radius of curvature R so as to contact the groove 17 at two points with one end of the contact piece main body 22;
Is a current-carrying contact portion formed in an arc shape with a radius of curvature so as to contact the small-diameter portion 20 on the other end side of the contact piece main body 22.

Here, the groove 17 which contacts the energizing contact portion 23
Will be described with reference to FIG. The groove 17 is formed by expanding the cross-sectional shape at an angle γ at a position where the groove 17 is in contact with the energizing contact portion 23 of the first conductor 15. The angle formed by the two points at which the energizing contact portion 23 contacts the side wall of the groove 17 is 120
At least 180 ° and less than 180 °.

Then, the contact piece 25 is formed by the above 22 to 24. Reference numeral 26 denotes a plurality of garter springs which are arranged on the outer periphery of each contact piece 25 and press each of the energizing contact portions 23 and 24 against the groove 17 and the contact portion 21. Each contact piece 2 is
5 is prevented from falling down. Then, the tulip contact 27 is formed by the steps 25 and 26. Reference numeral 28 denotes a shield arranged to cover the tulip contact 27 to reduce the electric field. Reference numeral 29 denotes a shield support fixed to the first conductor 15. The shield support 29 supports the shield 28.

In the contact device of FIG. 1, a plurality of contact pieces 25 are bundled by a plurality of garter springs 26 between respective contact portions 17 and 21 between the first conductor 15 and the second conductor 20. The connection is made at each of the contact portions 23 and 24 of the piece 25. Then, due to the contraction force of the garter spring 26, each of the energizing contact portions 23, 24 of each of the contact pieces 25
(Contact force) that presses the contact pieces 25 against the groove 17 and the small diameter portion 21 of each of the conductors 15 and 20, and each contact piece 25 is connected between the first and second conductors 15 and 20 by this contact force.
A current path between the first conductor 15 and the second conductor 20 is formed.

Here, the component of the contact force at which the energizing contact portion 23 comes into contact with the groove 17 will be described with reference to FIGS. FIGS. 3 and 4 are enlarged views showing the contact state between the first conductor and the contact piece in the contact device in FIG. 1. Arrows F, F1 and F2 indicate the magnitude and direction of the contact force, respectively. Is shown.

FIG. 3 shows, for example, the angle θ formed by the component forces F1 and F2 obtained by dividing the contact force F by the angle γ of the groove 17.
Is 120 °, and the magnitude of the force of F1 and F2 is equal to F from the parallelogram rule. FIG. 4 shows that the angle θ formed by the component forces F1 and F2 obtained by dividing the contact force F by the angle γ of the groove 17 is 12 degrees.
This shows a case where the angle is 0 ° or more, for example, a state where the forces are balanced when θ = 150 °, and the magnitudes of the forces F1 and F2 are naturally larger than F. Therefore, even if there are two contact points, it is possible to obtain a contact force at each contact point that is equal to or greater than that at a single contact point.

As described above, according to the first embodiment, the position where the arc-shaped energizing contact portion 23 of the contact piece 25 on the outer periphery of one of the pair of conductors 15 and 20 facing each other in the axial direction comes into contact with each other. Groove 17 whose cross-sectional shape is expanded at a predetermined angle γ
Is formed and the expansion angle γ of the groove 17 is
The angle θ formed between the center of the circular arc of No. 3 and the two points where the energizing contact portion 23 contacts the side wall of the groove 17 is set to be equal to or greater than 120 and less than 180 °, and is equal to or greater than the case where the number of contact points is one. By contacting at two points with a contact force, the contact electric resistance can be reduced to 以下 or less, and the current carrying capacity can be increased.

Embodiment 2 5 is a front sectional view showing a configuration of a contact device according to Embodiment 2 of the present invention, FIG. 6 is an enlarged view showing a contact portion of the contact device of FIG. 5, and FIG. 7 is a contact force at the contact portion of FIG. FIG. 4 is a vector diagram showing directions of the sword.
In each figure, the same components as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In each of the figures, reference numeral 31 denotes a fixed-side first conductor forming an electric path, 32 denotes a small-diameter portion formed at the end of the first conductor 31, and 33 denotes a cross-sectional shape formed on the outer periphery of the small-diameter portion 32. Are formed in such a manner as to project in an arc shape with a radius of curvature R. A plurality of contact portions 34 are engaged with the outer periphery of the holding plate 18 at predetermined positions and both ends are formed so as to be able to contact the respective current contact portions 33 and 21. The contact piece main body 35 is formed on one end side of the contact piece main body 34 and is positioned at a position where the contact piece main body 35 comes into contact with the current-carrying contact portion 33.
A groove as a contact portion expanded by the contact piece main body 34
Is a current-carrying contact portion that is formed to protrude in an arc shape at the other end side. And the contact piece 37 is formed by the above 34 to 36,
A tulip contact 38 is formed by the above 18, 26 and 37.

Here, the groove 35 which contacts the energizing contact portion 33
Will be described with reference to FIG. The groove 35 is expanded at an angle γ at a position where the contact piece 37 contacts the energizing contact portion 33 of the first conductor 31 and the angle
The angle formed between the center of the circular arc of No. 3 and the two points where the energizing contact portion 33 contacts the side wall of the groove 35 is set to be 120 ° or more and less than 180 °.

In the contact device shown in FIG. 5, when the energized contact portion 33 of the first conductor 31 and the groove 35 of the contact piece 37 contact each other, the arc-shaped energized contact portion 33 contacts the side wall of the groove 35 at two points. And the contact force F by the garter spring 26 is
As shown in FIG. 6, two-directional forces F1, acting on each contact point,
Decomposed equally into F2.

For example, when the angle θ formed by F1 and F2 is 1
In the case of 20 °, as shown in FIG.
The magnitude of the forces of 1 and F2 will be equal to F. Also, F1
As the angle formed by F1 and F2 becomes larger than 120 °, although not shown, the magnitudes of F1 and F2 naturally become larger than F from the balance of the forces. Therefore, even if the number of contact points is two, the contact force at each contact point can obtain a contact force equal to or greater than that when the number of contact points is one.

As described above, according to the second embodiment, the current-carrying contact portion 3 having a cross-sectional shape protruding in an arc shape on the outer periphery of one of the pair of conductors 31 and 20 axially facing each other.
3 is formed, and a groove 35 expanded at a predetermined angle is formed at a position where the contact piece 37 comes into contact with the current-carrying contact portion 33, and the spread angle of the groove 35 is set to be equal to the center of the arc of the current-carrying contact portion 33. Since the angle θ formed by the two points at which the contact portion 33 contacts the side wall of the groove 35 is set to be equal to or greater than 120 ° and less than 180 °, the contact force is equal to or greater than that of a single contact point, and By making contact at two points, it is possible to reduce the contact electric resistance to 以下 or less, and it is possible to increase the current carrying capacity.

Embodiment 3 FIG. FIG. 8 is a front sectional view showing a configuration of a contact device according to Embodiment 3 of the present invention, and FIG. 9 is an enlarged view showing an energizing contact portion of the contact device of FIG. In each of the drawings, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. In each figure, 41 is a fixed-side first conductor forming an electric path, 42 is a small-diameter portion formed at the end of the conductor 41, and 43 is an arc-shaped cross-sectional shape of the contact piece 25 in the circumferential direction of the small-diameter portion 42. Is a groove as a contact portion formed with a radius of curvature R1 larger than the radius of curvature R.

In the contact device of FIG. 8, a plurality of contact pieces 25 are bound by a plurality of garter springs 26 between the groove 43 of the first conductor 41 and the small diameter portion 21 of the second conductor 20.
Each of the contact pieces 25 is connected by each of the energizing contact portions 23 and 24. Then, due to the contraction force of the garter spring 26, each of the energizing contact portions 23 and 2 of each of the contact pieces 25
4 is applied to the groove 43 of the first conductor 41 and the small diameter portion 21 of the second conductor 20 (contact force). Due to this contact force, each contact piece 25 separates the first and second conductors 41 and 20.
The conductors are connected to form a current path between the first conductor 41 and the second conductor 20.

As described above, according to the third embodiment, the position where the arc-shaped energizing contact portion 23 of the contact piece 25 on the outer periphery of one of the pair of conductors 41 and 20 facing each other in the axial direction comes into contact with each other. The cross-sectional shape is an arc-shaped curvature radius R of the contact piece 25.
Since the groove having the larger radius of curvature R1 is formed, the contact state between the groove 43 and the current-carrying contact portion 23 is such that the concave surface and the convex surface come into contact with each other, and the contact between the convex surfaces is reduced. In comparison, the contact area between the concave surface and the convex surface increases the contact area even if the contact pressure is the same, so that the contact electric resistance can be reduced and the current carrying capacity can be increased.

Embodiment 4 FIG. 10 is a front sectional view showing a configuration of a contact device according to Embodiment 4 of the present invention.
1 is an enlarged view showing a contact portion of the contact device of FIG.
In each drawing, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description is omitted. In each figure, 45
Are a plurality of contact piece main bodies which are engaged with the outer periphery of the holding plate 18 at predetermined positions and whose both end portions are formed so as to be able to contact each of the energizing contact portions 33 and the small diameter portion 21. A groove as a contact portion formed with a radius of curvature R1 larger than the radius of curvature R of the current-carrying contact portion 33 at a position where the first conductor 31 comes into contact with the current-carrying contact portion 33; It is a current-carrying contact portion protruding in an arc shape. And
The contact piece 48 is formed by the above 45 to 47, and
6, 48, a tulip contact 49 is formed.

In the contact device of FIG. 10, a plurality of contact pieces 48 are bundled by a plurality of garter springs 26 between a current-carrying contact portion 33 of a first conductor 31 and a small-diameter portion 21 of a second conductor 20. The groove 46 of each contact piece 48 and the energized contact portion 4
7. Then, due to the contraction force of the garter spring 26, the groove 46 of each contact piece 48 and the current-carrying contact portion 47 are connected to the current-carrying contact portion 33 of the conductor 31 and the small diameter portion 21
Force (contact force) is acting on the surface. Due to this contact force, each contact piece 48 causes the first conductor 31 and the second conductor 20
The conductors are connected to form a current path between the first conductor 31 and the second conductor 20.

As described above, according to the fourth embodiment, the current-carrying contact portion 3 having a cross-sectional shape protruding in an arc shape on the outer periphery of one of the pair of conductors 31 and 20 axially opposed to each other.
3 and a groove 46 having a radius of curvature R1 larger than the radius of curvature R of the current-carrying contact portion 33 is formed at a position where the contact piece 48 comes into contact with the current-carrying contact portion 33. The contact state of the piece 48 with the groove 46 is such that the convex surface and the concave surface are in contact with each other. Therefore, as compared with the contact between the convex surfaces, even if the contact pressure is the same, the contact area increases, so that the contact electric resistance can be reduced, and the current carrying capacity can be increased.

Embodiment 5 In the first to fourth embodiments, the small-diameter portion of the first conductor is formed with a current-carrying contact portion that protrudes in an arc shape with a predetermined radius of curvature, and one end of the contact piece that comes into contact with the current-carrying contact portion is energized. A groove that contacts the contact portion at two points or an arc-shaped groove having a radius of curvature larger than the radius of curvature of the energizing contact portion is formed, and a predetermined radius of curvature is formed on the side of the contact piece that contacts the first conductor. Forming a current-carrying contact portion that protrudes in an arc shape, and a groove that contacts the current-carrying contact portion at two points at a contact position of the first conductor that contacts the current-carrying contact portion, or
The case where the current carrying capacity is increased by forming an arc-shaped groove having a radius of curvature larger than the radius of curvature of the current-carrying contact portion has been described. However, the present invention is not limited to the outer periphery of the small-diameter portion of the first conductor. Needless to say, even if the above-described configuration is applied to the outer periphery of the small diameter portion, the same effects as those of the above embodiments can be obtained.

[0033]

As described above, according to the first aspect of the present invention, the first conductor on the fixed side forming the electric circuit, the first conductor, and the end are arranged to face each other with a predetermined interval. A plurality of contact pieces which are radially arranged in contact with the outer circumferences of the two conductors so as to be in contact with the outer circumferences of the two conductors so as to extend between the two conductors; In the contact device provided with a spring for applying a contact force by pressing against the contact, a groove whose cross-sectional shape is expanded at a predetermined angle is formed at a position where the energized contact portion on the outer periphery of one of the two conductors contacts. At the same time, the opening angle of the groove is set to the angle formed by the center of the arc of the energizing contact portion and the two points where the energizing contact portion contacts the side wall of the groove.
Since it is configured to be at least 20 ° and less than 180 °, 2
It is possible to provide a contact device capable of reducing a contact electric resistance by making contact at a point and increasing a contact force and increasing a current carrying capacity without increasing the size.

Further, according to the second aspect of the present invention, the first conductor on the fixed side forming the electric circuit, and the first conductor on the movable side, in which the first conductor and the end are arranged to face each other with a predetermined interval therebetween, are provided. 2 conductors, a plurality of contact pieces radially arranged in contact with the outer circumferences of both conductors across the two conductors, and a contact provided with a spring for applying a contact force by pressing each contact piece against each conductor. In the slave device, an energizing contact portion having a cross-sectional shape protruding in an arc shape is formed on an outer periphery of one of the two conductors, and a groove which is expanded at a predetermined angle at a position in contact with the energizing contact portion of the contact piece. And the angle at which the center of the arc of the energizing contact portion and the two points at which the energizing contact portion contacts the side wall of the groove is 120 ° or more and less than 180 °. Contact at two points and increase the contact force It is possible to provide a contact device capable of reducing the air resistance and increasing the current carrying capacity without increasing the size.

Further, according to the third aspect of the present invention, the first conductor on the fixed side forming the electric circuit, and the first conductor on the movable side in which the first conductor and the end portion are arranged to face each other at a predetermined distance. 2 conductors, a plurality of contact pieces arranged radially in contact with the outer circumferences of the two conductors so as to be in contact with the outer circumferences of the two conductors, and a plurality of contact pieces formed in an arc shape, and each contact piece is pressed against each conductor. In a contact device having a spring for applying a contact force, a groove having a radius of curvature larger than an arc-shaped radius of curvature of a contact piece is formed at a position where a current-carrying contact portion on one of the outer circumferences of both conductors contacts. With this configuration, it is possible to provide a contact device capable of reducing the contact electric resistance by increasing the contact area and increasing the current carrying capacity without increasing the size.

Further, according to the fourth aspect of the present invention, the first conductor on the fixed side which forms the electric circuit, and the first conductor on the movable side in which the first conductor and the end are arranged to face each other at a predetermined distance. 2 conductors, a plurality of contact pieces radially arranged in contact with the outer circumferences of both conductors across the two conductors, and a contact provided with a spring for applying a contact force by pressing each contact piece against each conductor. In the slave device, an energizing contact portion having a cross-sectional shape protruding in an arc shape having a predetermined radius of curvature is formed on an outer periphery of one of the two conductors, and a curvature of the energizing contact portion is provided at a position where the energizing contact portion of the contact piece contacts the energizing contact portion. Provided is a contact device that has a configuration in which a groove having a radius of curvature larger than the radius is formed, so that the contact electric resistance is reduced by increasing the contact area, and the current carrying capacity can be increased without increasing the size. Can be.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a configuration of a contact device according to Embodiment 1 of the present invention.

FIG. 2 is a side sectional view of the contact device of FIG.

FIG. 3 is an enlarged view showing a contact portion of the contact device of FIG. 1;

FIG. 4 is an enlarged view showing a configuration different from FIG. 3 showing a contact portion of the contact device of FIG. 1;

FIG. 5 is a front sectional view showing a configuration of a contact device according to Embodiment 2 of the present invention.

6 is an enlarged view showing a contact portion of the contact device of FIG.

FIG. 7 is a vector diagram showing a direction of a contact force at a contact portion of the contact device of FIG. 6;

FIG. 8 is a front sectional view showing a configuration of a contact device according to Embodiment 3 of the present invention.

9 is an enlarged view showing a contact portion of the contact device of FIG.

FIG. 10 is a front sectional view showing a configuration of a contact device according to a fourth embodiment of the present invention.

FIG. 11 is an enlarged view showing a contact portion of the contact device of FIG. 10;

FIG. 12 is a front view showing a conventional contact device in a partial cross section.

[Explanation of symbols]

15 first conductor, 17 groove (contact portion), 20 second conductor, 23 current contact portion, 25 contact piece, 26 garter spring, 31 first conductor, 33 current contact portion, 3
5 groove (contact portion), 37 contact piece, 41 first conductor,
43 grooves (contact part), 46 grooves (contact part).

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Osamu Kisani 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (4)

[Claims] 1. A fixed-side first conductor forming an electric circuit, a movable-side second conductor whose end is opposed to an end of the first conductor at a predetermined interval, and between the first and second conductors. A plurality of contact pieces which are arranged radially in contact with the outer circumferences of the two conductors across the two conductors, and a spring for applying a contact force by pressing the respective contact pieces against the respective conductors to press the respective contact pieces against the respective conductors; In the contact device provided with, a groove whose cross-sectional shape is expanded at a predetermined angle is formed at a position where the energizing contact portion of the outer periphery of one of the two conductors contacts, and the expansion angle of the groove is increased. The angle formed by the center of the arc of the energizing contact and the two points at which the energizing contact contacts the sidewall of the groove is 120
A contact device, wherein the contact angle is not less than 180 ° and less than 180 °. 2. A fixed-side first conductor forming an electric circuit, a movable-side second conductor whose end is opposed to the first conductor at a predetermined interval, and between the first and second conductors. A plurality of contact pieces radially arranged in contact with the outer circumferences of the two conductors over the straddle, and a contact device having a spring for applying a contact force by pressing the contact pieces against the conductors; A current-carrying contact portion having a cross-sectional shape protruding in an arc shape is formed on the outer periphery of one of the two conductors, and a groove that is expanded at a predetermined angle at a position where the contact piece comes into contact with the current-carrying contact portion is formed. And the angle of expansion of the groove is set so that the angle formed between the center of the arc of the energizing contact portion and the two points where the energizing contact portion contacts the side wall of the groove is 120 ° or more and less than 180 °. Characteristic contact device. 3. A fixed-side first conductor forming an electric circuit, a movable-side second conductor whose end is opposed to the first conductor at a predetermined interval, and between the first and second conductors. A plurality of contact pieces which are arranged radially in contact with the outer circumferences of the two conductors across the two conductors, and a spring for applying a contact force by pressing the respective contact pieces against the respective conductors to press the respective contact pieces against the respective conductors; A groove having a radius of curvature larger than the arc-shaped radius of curvature of the contact piece is formed at a position on the outer periphery of one of the two conductors where the energizing contact portion comes into contact. Contact device characterized by the above-mentioned. 4. A fixed-side first conductor forming an electric circuit, a movable-side second conductor whose end is opposed to the first conductor at a predetermined interval, and between the first and second conductors. A plurality of contact pieces radially arranged in contact with the outer circumferences of the two conductors over the straddle, and a contact device having a spring for applying a contact force by pressing the contact pieces against the conductors; A current-carrying contact portion having a cross-sectional shape protruding in an arc shape having a predetermined radius of curvature is formed on an outer periphery of one of the two conductors, and a radius of curvature of the current-carrying contact portion is provided at a position where the contact piece comes into contact with the current-carrying contact portion. A contact device, wherein a groove having a larger radius of curvature is formed.