TECHNICAL FIELD

[001] The present subject matter generally relates to a motor, more specifically the subject matter relate to a motor for a diamond polishing machine, the subject matter further, relates to a method of manufacturing the motor and the diamond polishing machine thereof.

BACKGROUND

[002] Motors that produce minimum vibration and noise while operation have numerous applications. Specifically in industries such as diamond cutting industry, a motor that produces minimal or no vibration during the operation is highly desirable because an unstable, noise producing or vibrating motor could result in major losses in such applications. While an unstable, noise producing or vibrating motor is prone to failure but also adversely affect the value of diamonds. Value of a diamond depends on how best the diamond is polished and cut, better the polishing and cutting of the diamond, higher the value of the diamond.

Therefore, it is highly desirable that the motors employed in diamond cutting and polishing produce minimum or no vibrations.

[003] Achieving a substantially vibration free motor and polishing machines thereof has consistently remained a challenge, specially, where a polishing scaife of the machine is attached to a spindle of a motor and rotates at around 3000 rpm. Diamond polishing scaife refers to a wheel or a plate embedded with hard materials such as diamond particles or dust which is used for abrasive purposes in polishing a diamond. Motors for diamond scaife polishing are faced with problems such as frequent failure of bearings, inconsistent in quality of polishing and poor energy efficiency. The problems increase many fold when there is a need to polish gems of higher weights and work for longer durations. SUMMARY

[004] The present subject matter provides a solution that provides a motor and a polishing machine thereof, which is substantially vibration free.

[005] According one aspect the present subject matter provides the motor comprising: the first housing located at the distal end of the spindle of the motor. The first bearing disposed in the first housing. The spring holder disposed in the first housing. The spring holder comprises a spring having a first end and a second end and the first end of the spring is arranged to be in contact with the first bearing. According to a further embodiment, the spring holder has the cavity and the second end of the spring rests in the cavity. In another embodiment, the motor is provided the second housing located at the loading end of the spindle and the loading bearing and a second bearing is disposed in the second housing. In one embodiment, the loading bearing and the second bearing have dimensions with critical tolerance limits. The tolerance limits are adjusted to maintain at a level and concentricity to avoid mechanical humming the motor and any device thereof. In another embodiment, the motor is mounted on a frame, the frame comprises: the main frame, the support plate and the top plate. The motor and the support plate are mounted on the main frame, the top plate is mounted on the support plate. In another embodiment, the first pad is sandwiched between the support plate and the top plate to cause physical separation between the support plate and the top plate. In a further embodiment, the main frame is mounted on the base plate, and the base plate is mounted on the pad rubber and the bottom pad and the bottom pad is secured, using a fastener, to the base plate in a manner that an air pocket is left. The air pocket helps in creating vacuum for stabilizing the motor and any apparatus thereof and assists in leveling the same. In a further embodiment, the bottom pad is made of neoprene and the pad rubber is made of rubber. In a further embodiment, the main frame has a mounting end configured to mount the motor and a fastening end configured to be mounted on the base plate and the mounting end is narrower as compared to the fastening end. [006] According to a further aspect, the present subject matter provides a method of manufacturing a motor. According to another aspect the present subject matter also provides a method of manufacturing diamond polishing machine that employs the motor of the present subject matter. According one embodiment, the method comprises: providing the first housing located at the distal end of the spindle of the motor and disposing the first bearing in the first housing. The method includes disposing the spring holder in the first housing, the spring holder comprises the spring having the first end and the second end and the first end of the spring is arranged to be in contact with the first bearing. In a further embodiment, disposing includes suspending the spring into the cavity of the spring holder to rest the second end of the spring in the cavity. In another embodiment, the method includes providing the second housing located at the loading end of the spindle and the loading bearing and disposing the second bearing is in the second housing. In one embodiment, the loading bearing and the second bearing are spaced apart from each other using one or more spacers. The tolerances of the spacers and the loading bearing and the second bearing are set critically to control vibrations. In one embodiment the spacers are two in number and both the inner and the outer diameter of the loading bearing and the second bearing is locked with threaded nuts to ensure correct position of the loading and the second bearing and to distribute axial as well as radial load across the loading bearing and the second bearing. In further embodiment, the method includes mounting motor on a frame, the frame comprises: the main frame, the support plate and the top plate, the motor and the support plate are mounted on the main frame, the top plate is mounted on the support plate. In another embodiment, the method includes causing physical separation between the support plate and the top plate. In one embodiment, the causing physical separation includes sandwiching the first pad between the support plate and the top plate. In one embodiment, the method include mounting the main frame on the base plate, and mooting the base plate on the pad rubber and the bottom pad and securing the bottom pad, using the fastener, to the base plate in a manner that an air pocket is left. The air pocket assists in leveling the machine. Further the bottom pad is provided with spirals (not visible in drawing). The spirals assist in creating a vacuum for provide additional support and sturdiness when the machine is installed. In a further embodiment, the bottom pad is made of neoprene and the pad rubber is made of rubber. In one embodiment providing the main frame with a mounting end configured to mount the motor and a fastening end configured to be mounted on the base plate, the mounting end is narrower as compared to the fastening end.

BRIEF DESCRIPTION OF THE SUBJECT MATTER

[007] More details of the subject matter are described with reference to the following drawings, wherein:

[008] FIG. 1 shows a schematic diagram of a diamond scaife polishing machine according to an art;

[009] FIG. i(a) shows a more detailed diagram of the diamond scaife polishing machine according to an art;

[0010] FIG. 2 shows a schematic diagram of a motor according to an embodiment of the presents subject matter, the motor is deployed in a diamond polishing machine according to one embodiment of the present subject matter;

[0011] FIG. 2(a) shows a more detailed schematic diagram of fixing a top plate on a support plate of the motor deployed in the diamond polishing machine;

[0012] FIG. 2(b) shows a more detailed schematic diagram of the motor deployed in the diamond polishing machine;

[0013] FIG. 2(c) shows a schematic diagram of a second housing located at the loading end of the spindle of the motor deployed in a diamond polishing machine; [001 ] FIG. 3 shows a side view of arrangement of a set of springs arranged in the first housing located at the distal end of the spindle of the motor deployed in a diamond polishing machine; and

[0015] FIG. ^ shows a top view of arrangement of a set of springs arranged in a spring holder and located at the distal end of the spindle of the motor deployed in a diamond polishing machine.

DETAILED DESCRIPTION

[0016] The drawings are now described in more details. FIG. 1 shows a schematic diagram of a motor 10 employed in a diamond polishing machine 11 according to a prior art. The diamond polishing machine 11 according to an art comprises leveling bolts 1, a base plate 2, a main frame 3, a support plate , a top plate 5, a scaife 7, a scaife lock 8, a pre-loading washer g, a spindle 2 bearings 25 26, and bolts 12.

[0017] The leveling bolt(s) 1 are generally used for fixing the base plate 2 to a firm support generally the earth or a table. The main frame 3 supports weight of the motor 10. The motor 10 may be mounted in such a manner that the axis of rotation of the spindle 2 of the motor is vertical. The spindle 2 is mounted with the bearing 26 on the upper part of the spindle 2 and two bearings 25 at the lower part of the spindle 2 . The pre-loading washer 9 is used to hold the bearings in place. The scaife 7 may be held in place by means of the scaife lock 8. The support plate ^ and top plate 5 may be held by means of hexagonal bolts 12. The diamond polishing machine 11 has a number of limitations and disadvantages, for example, it is highly prone to vibrations and failures. Generally the diamond polishing machine 11 is loaded from the vertical top of the motor 10 through the scaife 7. It shall become apparent from the drawing that the top end of the spindle 2 is provided with a single bearing 26. Because load acts on the top end of the spindle 2 and the top end has only one bearing 26 this makes the bearing 26 and the spindle 24 prone to failure. Further, the base plate 2 and the main frame 3 are directly coupled to the support or the earth. Directly coupling does not provide any opportunity where the vibration may be decoupled resulting into propagation of vibration through the machine 11 which is undesirable. Similarly support plate and top plate 5 are directly coupled to each other through the bolt 12 leaving possibility of propagation vibration. Furthermore, the main frame 3, generally have a narrower base which is coupled to the base plate 2, as compared with top portion on which the top plate 5 is mounted resulting in reduced surface for balancing. In conventional design the bolt 12 is tightened directly with the top plate 5 and the mounting plate which causes transfer of vibration. Also, as may be noticed from the main frame 3 conventional designs are generally narrower at the bottom, which causes instability and vibrations.

[0018] Reference is now made to FIG. i(a). FIG. i(a) shows an enlarged view of lower part of the spindle 2 of the motor 10 showing the bearings 25 and the pre-loading spring 9. The bearings 25 are held in place by providing the preloading spring 9. It may be noted that the pre-loading spring 9 is made up of a single flexible material and it may not be able to effectively hold the bearings 25 in place when there is a thermal expansion experienced by the spindle 2 of the motor 10.

[0019] Reference is now made to FIG. 2. FIG. 2 shows a schematic diagram of a motor 100 according to an embodiment of the present subject matter, wherein the motor 100 is deployed in a diamond polishing machine 151 according to one embodiment of the present subject matter. The motor 100 comprises: a first housing ioi, a distal end 103, a spindle 105, a first bearing 107, a spring holder 109, a spring 111, a first end 113 of the spring 111 and a second end 115 of the spring 111, a cavity 117, a second housing 119 ,a loading end 123, a loading bearing 121, a second bearing 125, a main frame 127, a support plate i2gand a top plate 131, a first pad 133, a base plate 135, a pad rubber 137, a bottom pad 139, an air pocket 1 3, and a scaife 145, a scaife lock 1 9, a dust collector 153, a dust collector support ring 155, an angoor plate 157, a motor flange packing 157, fasteners 141, 161, 163, 165, and 167.

[0020] According to one feature the present subject matter provides the pad rubber 137, and the bottom pad 139. The diamond polishing machine 151 is mounted on the bottom pad 139 and the pad rubber 137 is disposed into the bottom pad 139. This feature of the present subject matter provides additional capability to absorb the vibration and therefore is advantageous over the prior art which merely provides mounting the diamond polishing machine on the leveling bolt (s) 1 (FIG. 1). The present subject matter further provides an air pocket 1 3. The air pocket 1 3 has cushioning effect and reduces vibrations caused due operation of the motor 100. According to another significant departure from the prior art, the present subject matter provides the main frame 127 having a mounting end configured to mount the motor 100 which is relatively wider as compared to a fastening end of the main frame 127 configured to be mounted on the base plate 135. The differential width of the mounting end and the fastening end may have a positive effect on reducing vibrations.

[0021] The fastener 165 may be used for attaching the support plate 129 with the top plate 131. The support plate 129 and the top plate 131 are made of metals e.g. mild steel. Instead of directly attaching the fastener 165 to the top plate 131 and support plate 129, as mentioned with reference to FIG.i according to a prior art, the first pad 133 may be interposed between the top plate 131 and the support plate 129. The first pad 133 may be made up of an elastic material such as rubber or neoprene. Providing the first pad 133 avoids direct metal to metal contact and therefore assists in suppressing vibrations to a large extent. [0022] Further, according to another feature of the present subject matter, motor 100 of the present subject matter provides a set of bearing at the loading end 123 namely, the loading bearing 121 and the second bearing 125. Which is another significant departure from the prior art as shown in FIG. 1. This feature of the present subject matter is advantageous as the motor 100 is loaded at the loading end 123 and therefore, relatively larger stresses are exerted at the loading end 123. The provision of two bearings at the loading end 123 may have a positive effect on reducing the vibrations further due to a sudden and uneven leading on the spindle 105 of the motor 100. According to a further feature spring holder 109 and springs 111. More details of the spring holder 109 and spring 111 shall become clear in after reading this specification.

[0023] Reference is now made to FIG. 2(a). FIG. 2(a) shows a schematic diagram of fixing a top plate 131 on a support plate 129 of the motor 100 deployed in a diamond polishing machine 151. Instead of directly attaching the fastener 165 to the top plate 131 and support plate 129, as mentioned with reference to FIG. 1, the present subject matter provides, the first pad 133 interposed between the top plate 131 and the support plate 129. The first pad 133 may be made up of an elastic material such as rubber or neoprene. Providing the first pad 133 avoids direct metal to metal contact and therefore assists in suppressing vibrations.

[002 ] Reference is now made to FIG. 2(b). FIG. 2(b) shows a schematic diagram of the first housing 101 located at the distal end of the spindle 105 of the motor 100 deployed in the diamond polishing machine 151. The spring holder 109 is disposed in the first housing 101. The spring holder has the cavity 117. The spring holder 109 comprises the spring 111 has the first end 113 and the second end 115 and the first end 113 of the spring 111 is arranged to be in contact with the first bearing 107 and the second end 115 of the spring 111 rests in the cavity 117.

[0025] Reference is now made to FIG.2(c). FIG. 2(c) shows a more detailed schematic diagram of the second housing 119 located at the loading end 123 of the spindle 105 of the motor 100 deployed in the diamond polishing machine 151. The motor 100 is provided the second housing 119 located at the loading end 123 of the spindle 105 and the loading bearing 121 and the second bearing 125 is disposed in the second housing 119. In one embodiment, the loading bearing 121 and the second bearing 125 have critical dimensional tolerances to avoid vibrations and noise to the overall operations of the diamond polishing machine 151.

[0026] FIG. 3 shows a side view of arrangement of a set of springs arranged in the first housing 101 located at the distal end of the spindle of the motor 100 deployed in a diamond polishing machine 151. The spring holder 109 is disposed in the first housing 101. The spring holder has the cavity 117. The spring holder 109 comprises the spring 111 has the first end 113 and the second end 115 and the first end 113 of the spring 111 is arranged to be in contact with the first bearing 107 and the second end 115 of the spring 111 rests in the cavity 117. It shall become clear to a person, after reading this specification that the FIG. 3 and other FIGs. of this specification shows sectional views and some details may not have been shown for the sake of brevity.

[0027] FIG. ^ shows a top view of arrangement of a set of springs arranged in the spring holder 109 and located in the first housing 101 located at the distal end 103 of the spindle 105 of the motor 100 deployed in the diamond polishing machine 151. In one example the spring holder 109 may be made of a flexible material e.g. polyethylene. In some other example, the spring holder 109 may be provided with a set of precision bores or holes which are effectively the cavities 117, for holding the springs 111. The cavities 117 maybe substantially equally spaced to balance the spring 111 (not shown in FIG.3) tension substantially uniformly on the periphery of the first bearing 107 located at the spindle.

According to one embodiment of the present subject matter, there are 24 equally spaced holes/cavities 117. However, a person skilled in the art may understand that the number of springs and holes may vary from design to design e.g., a 16 hole spring holder with 16 springs of 4 mm length distributed at substantially equal distances around the periphery of a bearing may also be employed.

[0028] The reference is further made collectively to FIG. 2, FIG. 3 and FIG. it. According to a further aspect, the present subject matter provides a method of manufacturing a motor 100. According to another aspect the presents subject matter also provides a method of manufacturing diamond polishing machine 151 that employs the motor 100 of the present subject matter. According one embodiment, the method comprises: providing the first housing 101 located at the distal end 103 of the spindle 105 of the motor 100 and disposing the first bearing 107 in the first housing 101. The method includes disposing the spring holder 109 in the first housing 101, the spring holder 109 comprises the spring 111 having the first end 113 and the second end 115 and the first end 113 of the spring 111 is arranged to be in contact with the first bearing 107. In a further

embodiment, disposing includes suspending the spring 111 into the cavity 117 of the spring holder 109 to rest the second end 115 of the spring 111 in the cavity 117. In another embodiment, the method includes providing the second housing 119 located at the loading end 123 of the spindle 105 and the loading bearing 121 and disposing the second bearing 125 is in the second housing 119. In one

embodiment, the loading bearing 121 and the second bearing 125 are spaced apart from each other using one or more spacers. The tolerances of the spacers and the loading bearing 121 and the second bearing 125 are set critically to control vibrations. In one embodiment the spacers are two in number and both the inner and the outer diameter of the loading bearing 121 and the second bearing 125 is locked with threaded nuts to ensure correct position of the loading bearing 121 and the second bearing 125 and to distribute axial as well as radial load across the loading bearing 121 and the second bearing 125. In further embodiment, the method includes mounting motor 100 on a frame, the frame comprises: the main frame 127, the support plate i2gand the top plate 131, the motor 100 and the support plate 129 are mounted on the main frame 127, the top plate 131 is mounted on the support plate 129. In another embodiment, the method includes causing physical separation between the support plate 129 and the top plate 131. In one embodiment, the causing physical separation includes sandwiching the first pad 133 between the support plate 129 and the top plate 131. In one embodiment, the method include mounting the main frame 127 on the base plate 135, and mooting the base plate 135 on the pad rubber 137 and the bottom pad 139 and securing the bottom pad, using the fastener 141, to the base plate 135 in a manner that an air pocket 1 3 is left. The air pocket 1 3 assists in leveling the machine. Further the bottom pad 139 is provided with spirals (not visible in drawing). The spirals assist in creating a vacuum for provide additional support and sturdiness when the machine 151 is installed. In a further embodiment, the bottom pad 139 is made of neoprene and the pad rubber 137 is made of rubber. In one embodiment providing the main frame 127 with a mounting end configured to mount the motor and a fastening end configured to be mounted on the base plate, the mounting end is narrower as compared to the fastening end.

[0029] In one embodiment, the present subject matter provides the springs 111 in the second housing. In another embodiment, the spring 111 are provided with the loading bearing 121. I n another embodiment the spring 111 is provided with the second bearing 125. It shall become clear to a person, after reading this specification, that for providing the spring 111 with either one or both of the loading bearing 121 and the second bearing 125, a spring housing similar to as described with reference to the spring housing 109 may be required.

[0030] Some of the advantages of the present subject matter may become clear from the following explanation. As illustrated, a tandem sets of bearings, namely loading bearing 121, second bearing 125 and first bearing 107 are used at the loading end 123 and the distal end 103 respectively. This feature of the present subject matter is advantageous for effective operation of the motor 100, and managing heat, temperature, vibrations, and other effects resulting from the change in physical parameters of operating conditions of the motor 100.

[0031] At the time of initial start up, the scaife 1 5 the first load experience on the aforementioned bearing is the load caused due the weight of the scaife 1 5 which rotates and therefore results into a radial load on aforementioned bearings. When the scaife 1 5 is further loaded for polishing a diamond load is experienced by the spindle 105 and the first bearings 107. To address this additional axial load, the present subject matter provides springs 111. The spring 111 based on the load experienced by the spring 111 contracts or expands to mitigate the load and thereby protecting the bearings 107, 121 and 125.

[0032] Furthermore the spindle 105 may experience certain amount of preload based upon the location of the aforementioned bearings with reference to the spindle 105. Further, the spindle 105 may also experience temperature increase due to heat generated during the operation of the motor 100 and losses caused thereby, resulting in increase of length of spindle 105. This change in dimension will be seen by the aforementioned bearings as an increase in load, as an inner race is forced into the bearing. This phenomenon is u ndesirable, and it may cause rapid failure of the aforementioned bearings. The spring 111, with the bearings compensates for the increased lengths of the spindle 105 by appropriate compression and thereby avoids this adverse effect.

[0033] According to another embodiment, alteration in length of the spindle 105 or other parts of the motor 100 may be compensated using a floating housing with springs. The floating housing may mounted in a precision bore that is free to move in an axial direction. Springs 111 may be used to provide a constant pre-loading force against the spindle 105 in the axial direction. As the spindle 105 dimension increases due to thermal expansion, bearings loaded with the springs 111 may be free to move and hence the load experienced by the bearings 107, 121, and 125 does not change, as the total load is constantly maintained by the force exerted by the springs. It shall become clear, after reading this specification, that the example discussed in this specification shows only one bearing 107 at the distal end 103 and two bearings 121 and 125 at the loading end 123 and that an alternate embodiment, having both the distal end 103 and the loading end 123 with two bearing is understood from the teachings of the present subject matter without departing from the spirit and scope of the present subject matter. It shall further become clear to a person, after reading this specification, that the example discussed in this specification shown spring 111 attached at the distal end 103 and an embodiment, having spring 111 attached to both the distal end 103 and the loading end 123 is understood from the teachings of the present subject matter without departing from the spirit and scope of the present subject matter.

[003 ] When some parts of the motor 100 experience physical change, may be due to change in temperature of the motor 100 the spring 111 at least compensates by compression or expansion, for some such physical change experiences by some parts of the motor 100. Tolerance of the bearings may be controlled closely to reduce the humming noise, wear and tear and frequent failures of bearings.

[0035] In one of the embodiments of the present subject matter, the spindle 105 and motor 100 may be held in a housing. The housing may be designed as an integral part of machine tool. Many high speed spindle designs may utilize a cartridge type housing, as this may be the simplest to service, and the tolerances required for high speed may be easily obtained when the housing can be produced as a cylinder. Tolerances of various components maybe closely controlled to the extent of 5 to 10 microns in one of the embodiments of the present subject matter. In another one of the embodiments, tolerance limits for the bearings may be within micron precision.

[0036] In one embodiment of the present subject matter, the primary function of a spindle housing may be to locate the bearings. The spindle housing may support and locate the bearings accurately, and provide the utilities needed by the spindle system. In one of the embodiments, the spindle housing may be made robust and stiff, as the housing transfers all forces from the spindle to the machine tool.

[0037] High precision bearings, being run at top dN values, may be positioned exactly in terms of geometry and size. In addition, the housing may provide the lubrication, and other utilities required by the spindle. It shall become clear to a person that grease may be used for lubrication. In one of the

embodiments, the polishing machine for diamond comprises a half horse power motor vertically mounted according to desired specifications of the machine 151.

[0038] According to an embodiment, the present subject matter provides the machine 151 that is designed based on the engineering principal that broader base of a machine demonstrate relatively stable and vibration free machine and that the electric motor 100 of the machine 151 is configure to produce minimum to no vibration due to rotation and that the motor 100 dynamically balances the splindle 105 and elements attached thereto. Furthermore the present subject matter provides adjusting the tolerances in microns. Therefore substantially reducing any electrical and mechanical humming of the machine 151 and hence enabling high quality polishing of diamonds.

[0039] The present subject provides springs to withstand both the axial and radial loads experienced by the machine when in operation and a diamond is being polished. In some embodiments, the number of springs and its housing are designed to ensure that they withstand axial and radial both the loads. Further, for removing mechanical humming, the present subject matter provides rubber pads between the top plate and the mounting plate, which ensures minimal to no metal to metal contact and thus minimal to no vibrations and mechanical humming on top plate, which is very important in diamond polishing.

[00 0] A number of design improvements for motors used in the diamond polishing machines are proposed in the embodiments of the present subject matter. The improvements hereby proposed may result in reduced mechanical humming noise and vibrations, decreased rate of failure of the bearings and motors, increased overall efficiency, increase in the operations and increased consistency and accuracy of usage of the motors used in the diamond polishing machines. Overall tolerance of dimensions of various parts used in making the diamond polishing machines may be strictly controlled to reduce humming noise and vibrations. The base of the machine is broadened. The machine maybe mounted with anti-vibration pads at the pedestal and may also be provided with pads and washers for the fasteners used at the metal joints. Further, a set of springs has been provided with a spring holder at one of the bearings to

compensate for the thermal expansion of the motor spindle.

[00 1] While the subject matter may be susceptible to various

modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described herein. Alternate embodiments or modifications may be practiced without departing from the spirit of the subject matter. The drawings shown are schematic drawings and may not be to the scale. While the drawings show some features of the subject matter, some features may be omitted. In some other cases, some features may be emphasized while others are not. Further, the methods disclosed herein may be performed in manner and/or order in which the methods are explained. Alternatively, the methods may be performed in manner or order different than what is explained without departing from the spirit of the present subject matter. It should be understood that the subject matter is not intended to be limited to the particular forms disclosed. Rather, the subject matter is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as described above. The above description while describing the present subject matter has used some proprietary hardware and software as well as some proprietary terms of expression including trademarks or other copyrighted subject matter, the applicant has taken immense care in acknowledge the ownership of the proprietary subject matter. However, if the applicant has inadvertently omitted any such acknowledgement, the applicant states that any such omission is unintentional and without any malicious intention.