RU194637U9 - ELECTRIC MACHINE BRUSH ASSEMBLY - Google Patents

Abstract

The proposed utility model relates to electrical engineering, in particular, to the brush assemblies of an electric machine with indication of brush wear. The essence of the utility model is that the brush wear indication system includes a brush wear sensor mounted on a clip from the back of the brush and a brush wear indicator, consisting of the base mounted on the back of the brush, to which the indicator scale adjoins with a pressure lever to activate the brush wear sensor, while the indicator scale length is not more than the radial length brush wear. The technical result of the proposed utility model is to achieve the nominal parameters of the brush and increase the accuracy of brush wear control, with the simultaneous possibility of visual control of brush wear.

Description

Application area

The proposed utility model relates to electrical engineering, in particular to brush assemblies of an electric machine with indication of brush wear.

Prior art

As part of the brush collector of an electric machine, the brush is a wear-resistant, non-renewable element, which requires attention of maintenance personnel for its timely replacement.

Untimely replacement of the brush in the brush assembly can lead to damage to the collector or ring of the electric machine, on which the brush slides during the operation of the electric machine.

Therefore, on each brush there is always a “risk (division) of the maximum wear of the brush” - a label up to which safe brush operation is acceptable.

Various brush assemblies of an electric machine are known that are triggered by brush wear to a certain limit, which are located in the body of the brush (AS No. 540319, 552660, 783897).

A common disadvantage of these brush assemblies is that this design of brushes is not applicable for brushes with several live wires.

Known brush assemblies for an electric machine, see patents Nos. DE 1257951, DE 1809592, DE 1197972, DE 19738037, DE 102014214307, FR 1159362, US 7994683, US 9287674. The technical solution according to patent No. US 7994683 is selected as a prototype, containing a brush holder, in the holder of which there is a brush with a cover and current conductors, spring-loaded on the side of the cover with a spring fixed in the holder of the brush holder, and an indicator of wear of the brush.

A design feature of the known technical solution is that it uses a leaf pressure spring with a free end, which is adjacent to the wedge-shaped clip. A wedge-shaped pocket is made in the holder of the brush holder, into which the free end of the spring is inserted and fixed in it by a wedge-shaped clip. The spring head presses on the brush pad, which leads to its constant springing. The wear sensor is made in the lower part of the wedge-shaped pocket in the form of a lever rotating on the axis.

The disadvantages of the known technical solution is the use of small parts and the complexity of the assembly of the brush assembly, as well as the difficulty of setting the response value of the brush to ensure maximum wear, which leads to large "bits" that do not allow the brush to develop full wear. Another disadvantage is the impossibility of visual inspection of brush wear.

Utility Model Task

The objective of the proposed utility model is to achieve the nominal parameters of the brush and increase the accuracy of control of the wear of the brush.

Another objective of the proposed utility model is to simplify the design of the brush wear indicator system of the brush assembly of an electric machine.

Another objective of the proposed utility model is to increase the service life of the brush wear indicator system of the brush assembly of an electric machine.

Another objective of the proposed utility model is the development of new types of brush assemblies of an electric machine that can be used in brush collectors with dust extraction for generators with vertical and horizontal axis of rotation.

Another objective of the proposed utility model is to develop a brush assembly of an electric machine with the ability to visually indicate the amount of brush wear.

Other tasks and advantages of the proposed utility model will be considered below as the description and figures for it are presented.

The essence of the utility model

A well-known brush assembly of an electric machine, comprising a brush holder, in the holder of which there is a brush with a pad, spring-loaded on the side of the pad with a spring fixed in the said clip, and a brush wear indication system, according to the proposed utility model, the brush wear indication system includes a brush wear sensor mounted on holder from the back of the brush, and a brush wear indicator, consisting of a base mounted on the back of the brush, adjacent to the indicator scale with a push lever for triggering of the brush wear sensor, while the length of the indicator scale is not more than the radial length of the allowable brush wear.

Also, according to an embodiment of the proposed utility model, the indicator scale, together with the pressure lever, is painted in a bright contrasting color.

Figures

When considering examples of the proposed utility model, narrow terminology is used. However, the proposed utility model is not limited to the accepted terms and it should be borne in mind that each such term covers all equivalent solutions that work in a similar way and are used to solve the same problems.

FIG. 1 - shows a brush assembly of an electric machine.

FIG. 2 is a side view of FIG. 1.

FIG. 3 is a section A-A of FIG. 1.

FIG. 4 - section BB is shown. FIG. 2.

FIG. 5 is a top view of FIG. 1.

FIG. 6 - indicator of wear of the brush.

FIG. 7 is a top view of the brush wear indicator of FIG.

The list of positions depicted in the above figures 1-7:

1 - holder of the brush holder;

1 ₁ - wedge-shaped pocket;

1 ₂ - holder holder 1;

2 - brush;

3 - overlay;

3 ₁ - shock-absorbing pad;

4 - holes for sealing conductors;

5 - spring;

5 ₁ - clip spring 5;

5 ₂ - spring head 5;

6 - indicator of wear of the brush 2;

6 ₁ - indicator base;

6 ₂ - indicator scale;

6 ₃ - pressure lever;

6 ₄ - holes for conductors;

7 - brush wear sensor 2;

L is the length of the indicator scale 6 ₂ .

Terms and Definitions

In accordance with GOST 12232-89 "Brushes of electric machines" when describing brushes, the terms are used:

t is the tangential size of the brush;

a is the axial size of the brush;

t * a - working (contact) surface of the brush, providing sliding contact with the surface of the collector or ring of an electric machine;

r is the radial size of the brush.

The following terms are used in the description of the implementation example:

contact (working) surface of the brush - a surface that slides along the collector or ring of an electric machine.

the back surface of the brush is the surface on which the plate with current conductors and the wear indicator are located, opposite to the working surface of the brush.

lateral surfaces of the brush - surfaces sliding in the holder of the brush holder.

Implementation example

The proposed brush assembly of an electric machine includes a holder 1 for a brush holder, in which there is a brush 2 with holes 4 for sealing conductors (current-carrying wires that are not shown in the figures), a rider-type pad 3, a rubber pad 3 ₁ under the pad 3 and a wear indicator system brush 2, including a wear indicator 6 and a wear sensor 7 (limit switch), mounted on a clip 1.

The wear indicator 6 (Fig. 6, 7) is made of rolled or sheet steel in the form of a simple profile part mounted on the back surface of the brush 2 under the shock-absorbing pad 3 ₁ and fixed to the brush by the pad 3.

The dimensions t ₁ and a _{1 of the} base of the indicator 6 _{1 are} determined by the dimensions t and a of the brush 2, the dimensions a ₂ correspond to the size of the legs of the lining 3, when installed on the brush 2, the wear indicator 6 is fixed on the brush 2.

As the brush 2 deteriorates under the influence of the spring 5, the pad 3 is constantly pressed on the back surface of the brush 2, as a result of which the brush 2 together with the wear indicator 6 goes inside the holder 1 of the brush holder, while the indicator scale 6 ₂ and the pressure lever 6 ₃ remain outside holder 1. The length L of the scale indicator on February ₆ does not exceed the working length of the brush 2. The scale indicator February ₆ together with the push lever ₆ March contrasting red colored paint that allows the operator to control visually the wear of the brush 2 from a safe distance Not closer to the current collector. When the length of the working part of the brush 2 decreases to 2-3 mm (to the risk of extreme wear), the pressure lever 6 _{3 of} the wear indicator 6 presses the wear sensor 7 of the brush 2, which transmits an electrical signal to the control system (not shown in the figures), providing additional reserve time for the operator to take the necessary measures to replace the brush 2.

The electrical low-current circuit of the control system of the wear sensor 7 is not connected to the power circuit of the brush 2, which avoids electrical overloads of the current collector control system.

The main part of the elements of the display system is located in the region of the lateral surface of the brush holder, which makes it possible to use a coil spring 5 in the central zone of the brush holder, which provides constant force as the brush 2 wears out.

The indication system is made taking into account its use on brushes 2 with both a single current lead and with several conductors that are embedded in holes 4 located on the back surface of the brush 2, which makes it possible to reduce the diameter of each current lead and its rigidity, which is also an advantage of the proposed useful models. This facilitates the bending of live wires in the brush assembly, which is often necessary for structural reasons.

The presence of the proposed display system of the brush assembly does not complicate the process of replacing the brush 2 in the holder 1 of the brush holder and does not make it necessary to completely disassemble the brush holder and rebuild the control system for indicating wear of the brush 2, which is also an advantage of the proposed utility model.

The wear sensor 7 during operation of the current collector is in a free (not pressed) state and is pressed by the pressure lever 6 ₃ only if the critical wear of the brush 2 is achieved. This contributes to the long-term preservation of its performance and increase its working life.

The location of the wear sensor 7 on the holder 1 on the back of the brush 2 (away from the working surface of the brush 2) contributes to the absence of dust accumulation on it and on the wear indicator 6, which increases the reliability of the wear indicator of the brush 2 and increases the time of reliable operation of the wear sensor 7, which is also an advantage of the proposed utility model.

It is clear that when using the proposed utility model, the option can be realized when the indicator scale 6 ₂ contains labels for its height for the bend for different types along the radial length of the brushes 2, when the discussion staff can independently use the wear indicator 6 for different types of brushes 2, which is also an advantage of the proposed utility model. It is also possible that the indicator scale 6 ₂ and the pressure lever 6 _{3 are} painted with fluorescent inclusions to increase the quality of visual inspection.

The brush assembly of an electric machine, according to the proposed invention, operates as follows.

The base 6 _{1 of} the wear indicator 6 is placed on the back side of the brush 2, a cushion pad 3 _{1 is} placed on top, on which the pad 3 is mounted, as a result of which the pressure plate is securely fixed to the back side of the brush 2. It should be noted that the indicator scale 6 ₂ is located in the opposite the side of the brush (from the contact surface) and the bending of the pressure lever 6 _{3 is} made out of the holder 1, which allows you to place the wear sensor 7 on the holder 1 from the back of the brush 2. After that, the brush 2 is inserted into the holder 1 and the head is spring-loaded oh 5 ₂ springs 5. Spring 5 is mounted in a wedge-shaped pocket 1 _{1 of the} holder 1. Check the operation of the wear sensor 7. As the brush 2 is used, the radial length of the brush 2 decreases as a result of abrasion of its working surface, as a result of which the back surface of the brush 2 and , accordingly, the pressure lever 6 ₃ moves to the holder 1. Upon reaching the maximum length of the radial wear of the brush 1, the pressure lever 6 ₃ presses the wear sensor 7, which leads to an open circuit, indicating the wear of the brush 2. Also, the operator can visually inspect the brush holder and the magnitude of the scale indicator 6 ₂ from the holder 1 protrudes, the operator can judge the degree of wear of the brush 2.

Technical result

The technical result of the proposed utility model is to achieve the nominal parameters of the brush and increase the accuracy of control of the wear of the brush, with the simultaneous ability to visually control the wear of the brush and increase the accuracy of control of its wear.

Claims (2)

1. A brush assembly of an electric machine, comprising a brush holder, in a clip of which a brush with a pad is located, spring-loaded on the side of the pad with a spring fixed in the clip, and a brush wear indication system, characterized in that the brush wear indication system includes a brush wear sensor mounted on holder from the back of the brush, and the indicator of wear of the brush, consisting of a base mounted on the back of the brush, which is adjacent to the indicator scale with a push lever to trigger the wear a brush, the length of the indicator scale is not more permissible radial length of the brush wear. 2. The brush assembly according to claim 1, characterized in that the indicator scale together with the pressure lever are painted in a bright contrasting color.

Images