TECHNICAL FIELD
The subject matter described herein, in general, relates to a brush plate assembly for a motor and in particular, relates to a moulded brush plate assembly with integrated capacitors/inductors and earthing contacts.
BACKGROUND
A brush plate assembly is used in variety of electrical equipments including motors and alternators. Typically, the brush plate assembly of a motor includes a brush plate and brush boxes. Each of the brush box houses a brush that contacts with the a commutator housed in the brush plate. The brush plate assembly operates under extreme conditions, like high temperature and vibrations.
During normal operation, the motor generates undesirable electromagnetic signals, which tend to interfere with the operation of the motor. Therefore, the motor requires electromagnetic interference (EMI) shielding to prevent any electromagnetic signals, generated during operation, from escaping and interfering with other electronic devices. In order to filter out the electromagnetic signals, generated during the operation of a motor, EMI components such as capacitors/inductors are provided on the motor.
Conventionally, motors are provided with a separate space for accommodating the EMI components thereon. Moreover, a cover plate of the motor accommodates earthing contacts. Thus, placing the EMI components and the earthing contacts at separate locations occupies additional space for both the EMI components and the earthing contacts in the motor.
Fig. la illustrates a conventional brush plate assembly 100. The conventional brush plate assembly 100 normally includes brush boxes 105. The brush boxes 105 are attached to a brush plate subassembly 110. Each of the brush box 105 houses a brush 115 and a brush spring 120.
Fig. lb exemplarily illustrates an armature assembly 125 having a commutator 130. On assembling the armature assembly 125 with the brush plate assembly 100, the brushes 115 come in contact with the commutator 130 of the armature assembly 125 to transfer electric current. Conventionally, the EMI components, used to filter the electromagnetic interference, are provided in a separate space in the motor. Further, the earthing contacts are disposed on the cover plate of the motor. Moreover, the location of the EMI components away from the point of generation of electromagnetic waves results in less filtration of the electromagnetic interference.
SUMMARY
The subject matter described herein is directed to a moulded brush plate assembly of a motor that accommodates electromagnetic interference (EMI) components for filtering the electromagnetic signals on a brush plate. The brush plate further accommodates the earthing contacts, thereby eliminating the need for separate space in the motor.
The moulded brush plate assembly includes a plate having a plurality of holes. A plurality of capacitors and inductors are provided on one side of the plate. Each of the capacitors and the inductors is fixed on the plate through a pair of holes. Another side of the plate has a plurality of slots for accommodating earthing contacts. Each of the earthing contacts is positioned in a slot and is affixed to the second side through the pair of holes. In one embodiment, the plate is made of Nylon 46 to withstand high temperature in the motor.
By positioning of the EMI components and the earthing contacts on the brush plate assembly, the requirement of separate space within the motor for holding the EMI components and earthing contacts is eliminated, thereby making the brush plate assembly compact.
These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
BRIEF DESCRIPTION OF DRAWINGS
The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description, appended claims, and accompanying drawings where:
Fig. la illustrates a conventional brush plate assembly for a motor.
Fig. lb exemplarily illustrates an armature assembly for a brush plate assembly of
Fig. la
Fig.2a illustrates a top view of a first side of a moulded brush plate subassembly with EMI components disposed thereon in accordance with the present subject matter.
Fig.2b illustrates a top view of the first side of a plate of the moulded brush plate subassembly of Fig 2a..
Fig.2c illustrates a top view of the second side of a plate of the moulded brush plate subassembly with the earthing contacts disposed thereon.
Fig.2d illustrates a top view of the second side of the moulded brush plate subassembly.
Fig.3a illustrates the perspective view the brush box subassembly.
Fig.3b illustrates the perspective view of a brush of the brush box subassembly of
Fig.3a.
DETAILED DESCRIPTION
A moulded brush plate assembly for a motor is described herein. The moulded brush plate assembly includes a plate having a plurality of holes. The plate is made of Nylon 46 and accommodates a plurality of EMI components such as capacitors and inductors on one of its sides. A plurality of slots is provided on the other side of the plate for accommodating earthing contacts. The capacitors, inductors as well as earthing contacts are affixed to the plate through the holes provided in the plate. The moulded brush plate assembly further includes brush boxes provided on the other side of the plate. Each of the brush boxes houses a brush with a braid. The braid is used to retract the brush in the brush box during assembling of an armature assembly with the moulded brush plate assembly.
A brush plate assembly includes a brush plate subassembly 200 as illustrated in Fig 2a, and a brush box subassembly. The brush plate subassembly 200 further includes a brush plate 202. In one embodiment, the brush plate 202 is made of Nylon 46 material.
Fig.2a illustrates a top view of a first side of a moulded brush plate subassembly 200 with EMI components disposed thereon in accordance with the present subject matter while Fig.2b illustrates a top view of the first side of a plate of the moulded brush plate subassembly of Fig 2a.
The plate 202, having a first side 204 and a second side 206, has a plurality of holes for accommodating a plurality of electromagnetic interference (EMI) components 208 and earthing contacts 210. The EMI components 208 include of one or more inductors 212 and 214 and one or more capacitors 216, 218, and 220. In the present embodiment, three capacitors 216, 218, and 220 and two inductors 212 and 214 are accommodated on the first side 204 of the plate 202. A pair of holes 221 and 222, shown in Fig 2b, is provided for accommodating the first inductor 212 whereas another pair of holes 224 and 226, shown in Fig 2b, is provided for accommodating the second inductor 214. The first capacitor 216 is accommodated in the pair of holes 220 and 226 shown in Fig 2b. The second capacitor 218 is accommodated in the pair of holes 224 and 228 shown in Fig 2b. A third capacitor 220 is accommodated in the pair of holes 222 and 230 shown in Fig 2b.
While the present embodiment has two inductors 212 and 214 and three capacitors 216, 218, and 220, the subject matter can be embodied in many other ways. Depending on the requirements, the number of inductors and capacitors can be determined using engineering principles known to any person skilled in the art. The arrangement of the inductors and the capacitors would be obvious to a person skilled in the art or the subject matter of routine experimentation.
Fig.2c illustrates a top view of the second side of a plate 202 of the moulded brush plate subassembly 200 with the earthing contacts disposed thereon whereas Fig.2d illustrates a top view of the second side of the moulded brush plate subassembly 200.
The second side 206 of the plate 202 has slots 232, 234 and 236 and holes 238, 240 and 242 in sequence for accommodating earthing contacts 210. The second side 206 of the plate 202 also has undercuts 244, 246 and 248 and slots 250, 252 and 254 respectively for accommodating brush box subassemblies.
The brush plate subassembly 200 can have more or less slots than mentioned in the present embodiment. The slots and holes can also be rearranged in many other ways. The number of slots/holes and their arrangement would be obvious to a person skilled in the art or the subject matter of routine experimentation.
Fig. 3a shows a perspective view of the brush box subassembly 300 of the brush plate assembly in accordance with one embodiment of the present invention. The brush box subassembly 300 includes a brush 302 with a bridle 304, a brush spring 306, an anchoring profile 308 and a brush box 310.
Fig. 3b shows a perspective view of the brush 302 with the bridle 304.
A plurality of brush boxes 310 are provided on the second side 206 of the plate 202. Each of the brush boxes houses the brush 302 as well as the brush spring 306. The brush spring 306 forces the brush 302 to protrude out of the brush box 310 in order to make contact with a commutator of an armature assembly. During assembling of the armature assembly with the brush plate assembly, the brush 302 is retracted from its position with the help of the bridle 304. The anchoring profile 308 is provided on the brush box 310 to hold the brush 302 in retracted position. The anchoring profile 308 is
located on the brush box 310 in such a manner that the bridle 304 can be tied around the anchoring profile 308 for holding the brush 302 in the retracted position. Once the armature assembly is fitted with the brush plate assembly, the bridle 304 is untied in order to release the brush for contact with the commutator.
In the above mentioned embodiment of the present subject matter, the brush box subassembly 300, the brush 302, the brush spring 306 and the EMI components 208 are placed on the first side 204 of the brush plate 202. However, the earthing contacts 210 are placed on the second side 206 of the brush plate 202.
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.

I/We claim:
1. A moulded brush plate assembly for a motor, said brush plate assembly comprising:
a plate having
a plurality of holes, a first side and
a second side having a plurality of slots; a plurality of capacitors disposed on said first side,
wherein each of said capacitors are disposed on said first side through a pair of said holes; a plurality of inductors disposed on said first side,
wherein each of said inductors is disposed on said first side through a pair of said holes; and a plurality of earthing contacts disposed on said second side,
wherein each of said earthing contacts is positioned within said slots
and
wherein each of said earthing contacts are affixed to said second side through a pair of said holes.
2. The moulded brush plate assembly as claimed in claim 1, wherein said plate is made of Nylon 46.
3. The moulded brush plate assembly as claimed in claim 1, wherein said first side accommodates three capacitors.
4. The moulded brush plate assembly as claimed in claim 1, wherein said first side accommodates two inductors.
5. The moulded brush plate assembly as claimed in claim 1, wherein said second side accommodates three earthing contacts.
6. The moulded brush plate assembly as claimed in claim 1 further comprises a plurality of brush boxes disposed on said second side.
7. The moulded brush plate assembly as claimed in claim 6, wherein each of said brush boxes further comprises a brush and a braid for retracting said brush.