RU2735853C2 - Switching device - Google Patents

Abstract

FIELD: electrical equipment.

SUBSTANCE: invention can be used in commutator electric motor of direct current with improved switching properties. Besides, the technical result is longer service life. Switching device comprises a commutator-switching unit made in the form of cylindrical gear pair of internal engagement, wherein mounted at anchor wheel consists of split in middle part on tooth and insulated spacer of T-shaped section separating tooth and covering its top, half teeth, to which are connected lead sections of machine armature winding, wherein solid gears are made of electrographic or metal-graphite material with possibility of free rotation on axes located near neutral, and have continuous end face contact with terminal fixed terminals.

EFFECT: technical result consists in improvement of reliability of collector and improvement of manufacturability of assembly, by improving switching, increasing inter-breakdown voltage and reducing friction losses in unit.

3 cl, 7 dwg

Description

The invention relates to the field of electrical engineering and can be used in a collector DC electric motor with improved switching properties.

This alleged invention is based on the idea of improving the commutation of DC collector machines by changing the principle of transferring current from a rotating armature to fixed terminals, increasing the interlaminate voltage and reducing friction losses in the assembly (see, for example, B.K.Tur. To the issue of commutation in machines direct current. // Electricity. 1956. № 11).

The essence of the proposed technical solution is obvious, since the introduction of new previously unknown structural elements and technological operations in the manufacture of a new type of collector is an unknown set of features with obtaining an additional technical result and a positive effect, namely, improving the commutation of DC collector machines by changing the principle of transferring current from a rotating anchors on fixed terminals, increasing the interlaminate voltage and reducing frictional losses in the unit (see, for example, BK Tur To the question of commutation in DC machines. "Electricity", 1956, No. 11).

"State of the art"

The known design of the switching device of a DC electric machine, consisting of a number of plates located along the generatrix of an isolated cylinder, fixed on the armature shaft and alternately connecting adjacent plates in the switching zone to fixed terminals. In this case, every two oppositely located plates are connected to two opposite points of the armature winding. Oppositely coaxially mounted brushes contact the plates, passing from one pair of plates to another when the armature rotates. The collector plates are insulated from adjacent ones with fiber or mica spacers. The ends of the plates are connected to the respective output ends of the winding.

The disadvantages of the plate-brush assembly are:

- the use of scarce materials in the manufacture;

- the need to increase the overall dimensions of the active parts of the contact;

- defects of the collector cylinder, such as eccentricity, ovality, breakage (at certain points of the surface), progressing in operation under the influence of dynamic and electromagnetic forces, as well as as a result of loosening of the collector studs tightening and insulation shrinkage;

- wear of the collectors, due to the increased pressure of the brushes, poor-quality material of the elements, vibration, beating and high rotation speed of the collector;

- significant influence of the magnitude of the contact resistance between the brush and the collector, leading to instability of the current collection or its complete loss;

- sparking on sliding contact leading to burning of brushes and collector plates.

- accidental separation of the brushes from the collector due to defects in the assembly. This violation can cover all collector plates covered with brushes, but not simultaneously under all briquettes;

- significant influence of the current density under the brushes, contact resistance and violation of the machine commutation.

Also known are the development of the collector-brush assembly using the radial surfaces of the collector plates. The reasons for the appearance of an arc turning into a circular fire are:

- covering the interlaminate space with copper collector plates [http://www.dissercat.com/content/zavolakivanie-kollektorov-tyagovykh-dvigatelei-elektrovozov];

- incorrectly chamfered from the collector plates, which makes it difficult to blow out brush dust;

- collector contamination and protrusion of mikanite collector plates.

With an increase in the interlaminate voltage to 34-36 V (an example for a traction motor of a locomotive) and in the presence of the above mechanical reasons, arcing may occur between adjacent collector plates, which turns into an arc discharge. Depending on the state of the collector-brush assembly, its purity and air humidity, the arc connects the collector plates between the plus and minus brush holders or the collector plates of the entire collector (circular fire).

In addition to these shortcomings of the unit itself, the brush traverse has low reliability, damage to which manifests itself in the form of a breakdown of the traverse ring, a disorder in adjusting the position of the brush holders on the traverse pins, and other damage to the unit parts.

"Disclosure of invention"

The technical result of the invention is to increase the reliability of the collector and improve the manufacturability of the assembly by improving the commutation, increasing the interlaminate stress and reducing friction losses in the assembly. In addition, the technical result is an increase in service life.

To implement the above technical result, a switching device is proposed, made with the possibility of alternately connecting in the switching zone of adjacent conductive collector plates through the collector-brush assembly to external, fixed terminals, while in order to improve switching, increase the interlaminate voltage and reduce friction losses in the assembly, according to the proposed invention, the collector-commutation unit is a cylindrical gear pair, and the wheel mounted on the anchor consists of split teeth in the middle part and insulated with a T-shaped gasket separating the tooth and covering its top, halves of the teeth forming a toothed cell, and to which the terminals of the armature winding sections of the machine are connected, while the one-piece gears are made of electrographite or metal-graphite material with the possibility of free rotation on the axes located near the neutral and have a continuous end sliding contact with the terminal fixed other terminals.

In addition, according to the present invention, in order to reduce the inter-lamellar stresses arising from self-induction in the armature winding sections, the insulation between the halves of the tooth is made of a material with a high dielectric constant to form an RC spark suppression capacitor.

The idea was developed in several directions. The main ones are:

1) The use of cylindrical gear pairs as a collector-commutation unit, and the wheel mounted on the armature is a fundamentally new collector. The gear wheel is installed from the end, frontal part of the armature, and the number of cavities between the teeth is equal to the number of winding sections. The diameter of the gear depends on the number of winding conductors and on the speed of rotation of the armature.

2) To ensure the existing dimensions of the anchor, a gear pair with internal gearing is used. The pair of internal engagement has many times less relative sliding of the working surfaces of the teeth and smaller dimensions with a large gear ratio and a small center-to-center distance.

3) The gear wheel mounted on the anchor consists of halves of the teeth split in the middle and insulated with a T-shaped gasket, forming a toothed cell, to which the outputs of the armature winding sections of the machine are connected.

4) Solid gears made of electrographite or metallographite material are in contact with the gear wheel. The gears rotate freely on the axes located near the neutral and have a continuous end sliding contact with the terminal fixed terminals.

It is advisable to use arched cylindrical gear elements (wheels) with spur, helical, chevron or similar teeth as a collector-commutation unit according to the proposed invention using internal gearing (it is possible to use external gearing if there is a margin for the overall limitations of an electric machine).

Tightening of the upper non-working part of the toothed collector wheel is performed by the wedge (dovetail) method.

The invention discloses the following details and analogies:

a) gears of internal gearing of increased mechanical strength, made of electrographite or metallographite material, and the axes of the gears have continuous sliding contact with external fixed terminals;

b) the teeth of the wheel form a toothed cell, consisting of split halves of adjacent teeth. In this case, the cell is connected to the conductor of the winding section by a cock [A. USSR No. 862285 MKI N01R 39/02 / B.i. 33 dated 09/07/81].

c) between the toothed cells there is an insulation made of a material with a high dielectric constant (for example, barium titanate) (Auth. Certificate of the USSR No. 89965, class H01r 39/06).

d) analogy:

"Brief Description of Drawings"

FIG. 1 shows the main view of the collector in the form of a gear pair of internal engagement.

Figure 2 shows the switching process when the armature winding section is short-circuited.

FIG. 3 shows the propagation of an arc discharge in a basic collector design. The arrow shows the path and length of the arc discharge.

FIG. 4 shows the propagation of an arc discharge according to the proposed option. The arrow shows the path and length of the arc discharge.

FIG. 5 is a schematic perspective view of a toothed cell and an insulator.

FIG. 6 shows a collector gear wheel brace.

FIG. 7 shows a general view of an electric machine with the proposed gear manifold.

"Implementation of the invention"

The switching device containing the collector in the form of a gear pair of internal gearing (see Fig. 1) consists of a collector wheel 1 and gear 2. The use of internal gearing ensures the placement of the entire unit within the dimensions of the armature cylinder.

Gear 1, installed from the end, frontal part of the armature, consists of toothed cells in the form of split teeth in the middle and isolated halves of teeth 3 and 4, to which leads 5 and 6 of sections (Fig. 2) of the armature winding of the machine are connected. In this case, the number of toothed cells is equal to the number of cavities between the teeth of the wheel and is equal to the number of armature winding sections. The diameter of the gear depends on the number of winding conductors and on the speed of rotation of the armature. Insulating spacers 7 of T-shaped cross-section, made of material with high dielectric constant, are installed between the toothed cells.

One of the options for solving the switching problem is constructive lengthening of the arc discharge path. FIG. 3, an insulating gasket 9 is located between the collector plates 8. The arrow shows the short path of the arc discharge.

FIG. 4, in an embodiment of the invention, the path and length of the arc discharge between the two toothed cells 3 and 4 of the teeth through the insulating gasket 7 significantly exceed the basic embodiment of the collector.

Figure 5 shows in perspective the main elements: the toothed cell 3 of the collector wheel and the gasket 7.

The tie of the upper non-working part of the toothed collector wheel is made by the wedge (dovetail) method (see Fig. 6). For the internal engagement of the pair, in contrast to analogues, the tie is installed outside the gear manifold. The toothed cell 3 is connected to the respective output end of the winding 10. by means of a cock.

The general arrangement of the gear manifold with field windings 11 and 12 is shown in FIG. 7.

One-piece gears 2, made of electrographite or metal-graphite material, rotate freely on axes located on neutral and have a continuous end sliding contact 13 with terminal fixed terminals 14.

Claims (3)

1. Switching device of a direct current machine, containing a commutating-commutating unit, characterized in that the commutating-commutating unit is made in the form of a cylindrical gear pair of internal engagement, containing a collector gear wheel installed from the end part of the armature of the machine, which consists of toothed cells formed of the halves of the teeth cut in the middle part, to which the armature winding leads are connected, insulating T-section gaskets are installed between the gear cells, and one-piece gears are in contact with the gear wheel, having the ability to rotate freely on axes located near the neutral, and having a continuous end sliding contact with terminal fixed terminals. 2. The device according to claim 1, characterized in that the insulating gaskets between the halves of the tooth are made of a material with a high dielectric constant with the formation of a capacitor of the spark-suppressing RC-chain. 3. The device according to claim 1, characterized in that the one-piece gears are made of electrographite or metallographite material.

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