BRUSHBLOCK WITH DUST COLLECTOR FOR SLIPRINGS

Abstract

 A dust collector for sliprings comprises a body of an insulating material forming a concave collection space and further comprising at least one attachment means for attaching the collector to a brush block or a brush holder sleeve.

Description

Field of the invention

[0001] The invention relates to dust collectors for slipring brushes and brush holders, slipring brushes and brush holders with dust collectors and brush block for holding brushes with dust collectors for use in an electrical power transfer device like a slipring or rotary joint.

Description of the related art

[0002] Sliprings are used to transfer electrical power between rotating parts of machines like wind power plants, CT scanners or electrical generators. There a brush, mainly comprising of electrically conductive material like carbon is sliding on a rotating cylindrical track of conductive material. Common materials for such tracks are steel or brass.

[0003] US patent 8,829,761 B2 discloses a brush block contained within a duct. A forced air stream is generated through the duct by a fan and dust particles are collected in a filter. This embodiment is comparatively complex and expensive and is therefore preferably used in large brush blocks having a large number of brushes and comprising a large total mass of carbon material.

Summary of the invention

[0004] The problem to be solved by the invention is to provide a simple and cost efficient means for collecting dust and debris from slip rings. Furthermore, maintenance should be easy and cost efficient.

[0005] Solutions of the problem are described in the independent claims. The dependent claims relate to further improvements of the invention.

[0006] From the prior art it is known to have a central dust collection device for multiple brushes. According to the invention the dust is collected at the individual brushes. This is much more efficient and avoids contamination of other parts with dust since the dust is collected close to where it is generated. As there is less dust in a slipring assembly and specifically on the sliding tracks, minimum airgap and creepage distance between tracks and brush holders of different potentials that are required by the relevant electrical safety standards are easier to maintain.

[0007] Generally, dust and debris (herein for simplicity simply called dust) has the tendency to follow gravitation and to fall to the ground. There may be other forces like a frictional force from the rotating drum accelerating particles into the direction of rotation. Also rotation may generate a more or less turbulent stream of air which may drive particles into the direction of rotation. Many long term tests have shown, that still a significant amount of particles is falling towards ground. Therefore, the directions from which dust particles pass the brushes differ between the positions. While at the side positions, the particles come from a side, the particles in the bottom position come from the top. In the top position, particles fall directly on the module and cannot be collected easily.

[0008] In an embodiment, a dust collector for slipring brushes or slipring brush holders comprises a body which may be made from an insulating material like a plastic material. The dust collector forming at least one dust collection space formed by a dust collection rim. The dust collector may have at least one attachment means for attaching the dust collector to a brush block or a brush holder sleeve. The collector rim may have a cylindrical or conical shape. Preferably, the dust collection rim has a concave shape which simplifies holding dust. The attachment means may be at least one clip or a pair of clips preferably to clip the dust collector to a brush holder and most preferably to the sleeve of a brush holder.

[0009] There may be different embodiments of dust collectors. A first type may be for mounting at bottom positions of a slipring assembly having a circular collecting rim forming a collecting space which preferably encloses the brush holder, such that no dust can fall downwards along the dust holder.

[0010] Another type may be optimized for mounting at side positions of a slipring assembly. Such a dust collector may have a concave shaped sidewall. The sidewall may only cover a portion of the circumference of a brush holder like an arc segment of 180 degrees. It may also cover a full arc and therefore have a hollow cylindrical shape. It is preferred, if the dust collector forms an open channel parallel to the brush holder such that an airstream can pass along this channel.

[0011] A universal type may comprise a circular sidewall and a closed bottom, preferably at the area of the clips. This embodiment may be used at bottom positions, side positions and in-between. The disadvantage is the slightly higher space consumption.

[0012] Although it is preferred, that the concave walls basically are arc-shaped, a cornered design having multiple corners will have the same effect and fall under the scope of the embodiments shown herein.

[0013] A dust collectors made from plastic material may be manufactured by 3D printing or injection molding. Plastic dust collectors are very flexible in their use, as they do not degrade insulation between parts. Alternatively, a dust collector may comprise metal.

[0014] In an embodiment, at least one dust collector is attached to at least one brush holder for holding a brush.

[0015] Generally, multiple dust collectors may be connected together or even may be made of one piece. This will simplify removal and assembly for exchange and cleaning of the dust collectors. Most preferably only collectors belonging to brushes of the same sliding track are held together. This increases isolation between separate tracks.

[0016] Preferably, dust collectors have ribs distributed over the dust collection surface to prevent dust to be sucked back. Also a rough surface of the dust collection surface is advantageous, especially if the dust collectors are for one time use.

[0017] For maintenance the dust collectors may simply be removed (unplugged) from the brush holders or brush block. They may be cleaned or exchanged and assembled again. The attachment of the dust collector to the brush holder or brush block might be by clip, bayonet or thread if removable, it might also be achieved by gluing, press fit, casting or 3D-printing if permanently attached.

[0018] Basically, the term carbon brushes relates to all kinds of brushes comprising at least a certain amount of carbon or graphite material. Such brushes normally have a basically cuboid shape and do not form a wire, like a wire brush which normally comprises a metal.

Description of Drawings

[0019] In the following the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiment with reference to the drawings.

Figure 1 shows a first dust collector for collecting dust coming from a side.

Figures 2 - 4 show further details of the first dust collector

Figure 5 shows a further embodiment of a dust collector.

Figures 6 - 7 show further details of the dust collector

Figure 6 shows a brush block

Figure 7 shows a second dust collector for collecting dust coming from the top.

Figure 8 shows a fully assembled brush holder.

Figure 9 shows a section of a brush block having two brush holders.

Figure 10 shows a slip ring assembly

[0020] In figure 1 a first dust collector 500 for side positions relative to a slipring is shown. Such collectors may be mounted in side positions as described later. The collectors preferably are from an insulating material and most preferably from a plastic material. The collectors have at least one holding means which may be a clip to hold the dust collector to a brush block or a brush holder sleeve 300. Furthermore, the collectors have a preferably concave shaped wall 520 forming a collection space 510. The collector may be attached to the brush block or brush holder sleeve such, that the collection space is sidewards and below the brush and may be open to the top such that it may collect dust falling from the brush towards ground. Preferably, the collecting space is radially oriented with respect to the longitudinal axis of a brush, preferably covering an angle of up to 180 degrees. It may cover any other suitable angle like 360 degrees or any fraction thereof. The collector 500 may have at least one clip 540, 541 for holding the collector to the brush holder sleeve. The sleeve may have a groove 330 for interfacing with the clip. It may allow holding the clip and therefore the dust collector for a long time in a stable and well defined position. The clip may be held by spacers 550 to allow a larger distance of the wall 520 to the brush holder sleeve, which allows for a certain air flow to allow cooling of the brush holder and a larger collection capacity.

[0021] Figure 2 shows a sectional side view of the dust collector as in Fig. 1.

[0022] Figure 3 shows a similar side view, but rotated about 90 degrees on a vertical axis. Here also ribs 530 are shown that act as dust traps to prevent dust to be sucked back. Furthermore, the ribs may help to increase the stability of the dust collector.

[0023] Figure 4 shows a top view of the dust collector having an arc-shaped wall 520 forming a collection space. Here a ring-shaped clip is shown, having two flexible end sections 540 and 541 which may interface with a holding groove of a brush holder sleeve. The clip may also be used without holding groove.

[0024] In Figure 5, another embodiment of a dust collector 400 for bottom positions relative to a slipring is shown. Such a collector has a rim 410 for collecting dust coming from a top side. The collector rim may have a cylindrical or conical shape. The collectors preferably are from an insulating material and most preferably from a plastic material. The collectors have at least one holding means which may be a clip 440, 441 to hold the dust collector to a brush block or a brush holder sleeve. The sleeve may have a groove 330 for interfacing with the clip. Furthermore, the collector has a preferably ring shaped wall 420 forming a collection space by rim 410 which may be approximately concave. The sidewall 430 may match to the outer contour of the sleeve and help fixing the dust collector to the sleeve. Preferably, it tightly encloses the sleeve, such that no dust may slide between the sleeve and the collector. The collector may be attached to the brush block or brush holder sleeve 300 such, that the collection space is below the brush and open to the top and may collect dust falling from the brush towards ground. Preferably, the collecting space is axially oriented with respect to the longitudinal axis of a brush. Here, the brush may be located within an inner space 310 of the brush holder sleeve. The sliding track is above the top of the sleeve. There may be a thread 320 for holding a locking cap.

[0025] Figure 6 shows a sectional side view of the collector as in Fig. 5.

[0026] Figure 7 shows a similar side view, but rotated about 90 degrees on a vertical axis of the drawing. Here a ring-shaped clip is shown, having two flexible end sections 440 and 441 which may interface with a holding groove of a brush holder sleeve. The clip may also be used without holding groove.

[0027] In figure 8 a fully assembled brush holder is shown in a sectional view. Here a carbon brush 360 is held within the brush holder sleeve 300. Preferably, the carbon brush 360 has a rectangular cross section. The inner space 310 of the sleeve is adapted to the carbon brush and therefore, preferably has a rectangular cross section too. A spring 350 presses the carbon brush out of the sleeve and towards a sliding track. A locking cap 340 holds the spring and the brush within the sleeve. For exchanging the brush, the locking cap may be unscrewed and removed. A brush block base 610 may provide means for holding the sleeve 300 together with the brush, the dust collector and other parts. The dust collector may also be directly attached to the brush block base, for example by means of a holding pin.

[0028] Figure 9 shows a section of a brush block having two brush holders held by a common brush block base 610.

[0029] In figure 10, a slipring module 100 with sliding tracks having a drum shape is shown. It may rotate about the axis 101 clockwise as shown by arrow 102. Basically, brushes and brush blocks may be arranged at any position. Here, four different positions are shown exemplarily. There are two side positions 201 and 203, a top position 204 and a bottom position 202.

List of reference numerals

[0030] 

100

slipring module

101

axis of rotation

102

direction of rotation

201

right side position

202

bottom position

203

left side position

204

top position

300

brush holder sleeve

310

inner space of sleeve

320

thread for locking cap

330

holding groove

340

locking cap

350

spring

360

carbon brush

400

dust collector for bottom positions

410

dust collection rim

420

ring shaped wall

430

sidewall

440, 441

holding clip

500

dust collector for side positions

510

collection space

520

concave shaped wall

530

ribs

540, 541

holding clip

550

spacer

610

brush block base

Claims

1. Dust collector (400, 500) for sliprings comprising a body of an insulating material forming a collection space (410, 510) and further comprising at least one attachment means (440, 441, 540, 541) for attaching the collector to a brush holder sleeve.

2. Dust collector according to claim 1,
characterized in, that
the collection space (410, 510) has a concave shape.

3. Dust collector according to claim 1 or 2,
characterized in, that
a concave shaped wall (520) is forming the collection space.

4. Dust collector according to claim 3,
characterized in, that
the concave shaped wall (520) is forming a channel with a brush holder sleeve.

5. Dust collector according to claim 1 or 2,
characterized in, that
a dust collection rim (410) is forming the collection space which has a cylindrical or conical shape.

6. Dust collector according to any one of the previous claims,
characterized in, that
at least one attachment means (440, 441, 540, 541) comprises a clip, preferably a pair of clips most preferably for to clip the dust collector to a brush holder and most preferably to the sleeve of a brush holder.

7. Dust collector according to any one of the previous claims,
characterized in, that
the dust collector comprises a plastic material.

8. Dust collector according to any one of the previous claims,
characterized in, that
the collection space comprises ribs that prevent dust to be sucked back.

9. Brush holder comprising a cylindrical, tubular sleeve (300) holding a dust collector according to any of the previous claims.

10. Brush holder according to claim 9 having a holding groove (330) for a holding clip (440, 441, 540, 541) of the dust collector.

11. Slipring brush block comprising at least one slipring brush holder according to claim 9 or 10 held by a brush block base 610.

12. Slipring comprising a sliding track and a slipring brush block according to the previous claim.

Drawing