JPS5834890B2 - Large current sliding contact device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to electrical devices, and more particularly to high current sliding contact devices.

Many devices used to transmit and distribute electrical energy require sliding contact current-carrying members.

Such devices include, for example, gas-insulated or air-insulated disconnectors, earthing switches, high-current busbar switches, and gas-insulated power transmission busbar joints.

These devices include two members adapted to move relative to each other between an open position where they are physically separated and a closed position where they are in mechanical contact and allow the flow of electrical energy.

The problem that needs to be solved in all of these devices is to reduce the electrical resistance at the point of mechanical contact between the two parts.

This resistance creates a Joule heating effect when current is passed through it, which limits the maximum amount of current that can be safely transmitted.

A number of ways to reduce this resistance include providing a number of separate contact points between the two separating members and applying a contact pressure that tends to bring the two members together.

Although the resistance is reduced by increasing the contact pressure and increasing the number of contact points between the two members, this method requires a significant amount of the mechanism for moving these members relative to each other between the open and closed positions. This means that the mechanism is expensive because it has to generate a force of .

PRIOR ART In prior art devices, a plurality of spring-loaded contact fingers are provided to form a number of contact points, on which a spring force is applied in a direction perpendicular to the direction of relative movement between two moving parts. do.

In such conventional devices, the contact resistance and temperature rise are within acceptable limits, but the force required to operate the many contacts requires expensive, energy-consuming operating mechanisms, or I didn't like it in that respect.

It is therefore desirable to have a contact device that is inexpensive and exhibits minimal contact resistance.

DISCLOSURE OF THE INVENTION According to the present invention, a resilient sliding contact device comprises a plurality of individually movable contact fingers adapted to make electrical sliding contact with a conductor associated with a housing, and a plurality of individually movable contact fingers each acting on said contact finger. an equal number of elastic biasing devices and a device coupled to the housing for causing the biasing devices to exert a spring force on each of the contact fingers, each spring force being associated with the respective contact finger; contact between the contact finger and the surface of the housing having a line of action generally parallel to the direction of relative movement with the conductor and operative to urge said contact finger against the surface of the housing so as to make electrical contact; The points are offset from the line of action of said springing force, so as to create a contact pressure perpendicular to the line of action of this force.

The invention further includes a resilient high current contact device having a cylindrical housing, circularly arranged and seated on the surface of the housing, each mating with a cylindrical conductor to provide electrical contact. a plurality of independently movable contact fingers brought into contact; a biasing device having an equal number of spring forces acting on each contact finger; and a biasing device adapted to exert a spring force on each contact finger. There is a device attached to said housing for actuating the device, each of these spring forces having a radial component and a larger axial component, the radial component being applied to each contact finger. The spring force creates a contact pressure between the cylindrical conductor in combination with the cylindrical conductor, and the axial component creates a contact pressure between the contact fingers and the housing surface. having a line of action parallel to the direction of relative motion of the contact fingers to press the contact fingers against the surface of the housing and create electrical contact therebetween.

The point of contact between the contact finger and the surface of the housing is out of the line of action of the spring force.

This spring force is therefore resolved into a component parallel to the direction of relative movement between the central conductor and the housing and a component perpendicular to the direction of this relative movement.

Embodiment 1 of the Invention In FIG. 1, a telescoping contact device 10 is shown, comprising a cylindrical movable central conductor 12 and an associated outer contact device 14.
is present in this contact device 10.

Once the center conductor 12 is inserted into the outer contact device 14,
A plurality of contact fingers 18 arranged along the inner peripheral surface of the cylindrical housing 16 and the outer wall surface of the center conductor 12 form electrical contact.

These contact fingers 18 are held against the contact surface 19 of the housing 16 by means of a plurality of coil springs 20 mounted one by one.

The other end of the coil spring 20 is placed in a groove 22 in a movable metal retaining ring 24 and fixed with a flexible adhesive.

A retaining ring 26 is placed on the inner circumferential surface of the housing 16 axially spaced apart from the contact finger 18 and is secured by a set screw 28 that fits into the inner circumferential surface of the housing 16 .

A mounting screw 30 is threaded axially into the retaining ring 26 and tightened against the retaining ring 24 to mount the coil spring 20 and impart the desired spring force to the contact finger 18.

As can be easily seen in FIG. 3, each contact finger 18 has apertures 32 through which extend metal circular locking rings 34.

The position of this rocking ring 34 is shown in FIG.

The contact fingers 18 are removed while the outer contact device 14 is assembled.
is threaded through the 1J34 stopper like a bead on a necklace.

The ends of the rocking ring 34 are then tightly tightened to spread them slightly and prevent the contact fingers 18 from falling out.

Effects 1 In addition to facilitating this assembly, the rocking ring 34 provides a lateral rocking barrier by holding the contact fingers 18 in close proximity to each other, so that the contact fingers 18 are kept in place during operation of the contact device 10. Prevent it from slipping out.

As shown in FIG. 3, each coil spring 20 is placed within a notch 36 having a width of dimension A in FIG.

The diameter of the coil spring 20 is dimension A as shown by dimension B.
It's thicker.

Therefore, before inserting the anti-sway ring 34 into the hole 32 of the contact finger 18, an automatic mechanical operation is performed to remove the coil spring. 0 is inserted from the side, the diameter of the coil spring 20 is compressed in the direction of the plane of the paper and stretched in the direction perpendicular to the plane of the paper.

Effect 2 Therefore, the coil spring 20
0 and will not fall off or become loose during assembly or operation of the contact device.

Each contact finger 18 has an end surface 38 and a bottom surface 40 intersecting this at an angle C of less than 90 DEG.

The spring force of the coil spring 20 presses the contact finger 18 against two points 42 and 44 on the inner surface of the housing 16.

This point 42 is offset from the line of action 46 of the coil spring 20.

As a result, the force received from the coil spring 20 is resolved into two components: a component 48 parallel to the direction of relative movement between the center conductor 12 and the outer contact device 14, and a component 50 perpendicular to this direction.

There, a contact pressure is maintained between the contact finger 18 and the housing 16 at points 42 and 44, and another contact pressure is maintained between the protruding surface of the contact finger 18 and the center conductor 12 at the contact point 52. .

By adjusting the offset distance E between the line of action 46 of the spring force and the point 42, the relative contact pressure can be adjusted as desired.

For example, a diameter of 2.36 inches (approx.
) center conductor and a total of 56 contact fingers.
kg) can be obtained, and the center conductor 12
and contact finger 18, approximately 3+ pounds (approximately 1.6
kg) contact pressure can be obtained.

Effect 3 This contact device has a continuous current of 4,000 amperes and a
It has the ability to carry a symmetrical fault current of 3,000 amperes.

The side walls 54 and 56 of the groove 22 of the retaining ring 24 are inclined at a predetermined angle with respect to the centerline of the coil spring 20.

This provides two important advantages.

First, the lower corner F (FIG. 3A) facilitates assembly of the contact device.

The upper corner C allows the center conductor 12 to be connected to the contact finger 18
When released from the coil spring 20, the coil spring 20 bends slightly, allowing the tip of the contact finger 18 to move towards the center.

The inner diameter of the retaining ring 24 is slightly larger than the outer diameter of the center conductor 12.

Effect 4: Therefore, correct contact can be obtained between the center conductor 12 and the outer contact device 14 not only when there is a slight center deviation between them, but also when there is some non-parallelism between their axes. .

This movement is possible because the inclined walls 54 of the grooves 22 cause the contact fingers 18 to move toward the center.

For example, when the angle G is equal to 13°, the mutual inclination of the axes of the central conductor 12 and the outer contact device 14 by up to 3° is possible.

Correct operation under these conditions is possible because, while misalignment of the axes can be corrected relatively easily by adjusting the component elements, it is extremely difficult to correct the mutual inclination of the axes. is important.

Advantage 5 Utilizing the contact finger 18 of the form disclosed herein:
During operation of the contact device 10, a wiping action occurs at points 52, 42° 44.

This means that the contact device 1 is
This is especially important when using 0.

Such encroachment occurring at the point of contact serves to increase resistance and result in higher operating temperatures.

The individual contact fingers 18 may be made in a precision blanking operation or in a three step operation including sintering, casting and annealing to increase conductivity.

With the device disclosed herein, nearly twice as many contact points can be used between the center conductor 12 and the outer contact device 14 as compared to devices made by conventional techniques and at the same cost.

The performance is therefore considerably improved and the total contact pressure between the contact fingers 18 and the center conductor 12 is reduced.

This allows the use of an inexpensive operating mechanism for operating the center conductor 12.

Embodiment 2 of the Invention Various types of structures can be used to bias the coil spring 20.

For example, as shown in FIG. 4, an integral member 29 that functions as both the retaining ring 24 and the retaining ring 26 can be used.

Both a groove 22 serving as a spring seat and a set screw 28 are provided in this member 29.

Other types of coil spring biasing structures are also available. It is also possible to provide contact fingers on the outer circumferential surface of the movable central conductor 12 instead of on the inner circumferential surface of the outer contact device 14.

In that case fewer contact fingers may be required to obtain the same size contact surface, but this shape may be preferable depending on the application.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a contact device according to an embodiment of the present invention, FIG. 2 is an end view with a part of the contact device shown in FIG. 1 removed, and FIG.
The figure is a partial sectional view of the contact device of FIGS. 1 and 2,
3A is a partially enlarged sectional view of FIG. 3; FIG. 4 shows a portion of a contact device according to another embodiment of the invention with the center conductor removed; FIG. FIG. In addition, in these drawings, the same reference numerals indicate corresponding parts, respectively. In the drawings, 12...--center conductor, 14...
... Exterior contact device, 16 ... Housing, 1
8... Contact finger, 20... Coil spring, 22... Groove, 24... Retaining ring, 26... Retaining ring, 28 ......Set screw, 30...Mounting screw, 32...Hole, 3
4... Wobble ring, 36... Notch,
42.44... Contact point between contact finger and housing, 46... Center line of coil spring (line of action of spring force), 52... Protruding surface of contact finger Contact point between and center conductor, 54°56...groove 22
side wall.

Claims (1)

[Claims] , 1 a cylindrical housing, a plurality of resilient contact fingers arranged circularly on the inner surface of said housing and each in electrical sliding contact with a cylindrical movable central conductor associated with said housing, each with a radial component and a larger axial component, the radial component creating a contact pressure between each of the contact fingers and the center conductor, and the axial component creating a contact pressure between the contact fingers and the interior of the housing. a spring device as many as the contact fingers, applying a spring force to each of the contact fingers to create a contact pressure with the surface; a retaining ring for holding the spring device attached to the nozzle; a retaining ring for holding the spring device; A sliding contact device for high currents, comprising holes drilled in a direction perpendicular to both components of the spring force, and a rocking ring passing through all of these holes.