GB2161406A

GB2161406A - Abrasive polishing/finishing machine

Info

Publication number: GB2161406A
Application number: GB08516131A
Authority: GB
Inventors: Haralampi Angelov Atanasov; Boris Georgiev Makedonski; Stefan Jelyazkov Kochev; Lyubomir Pavlov Alipiev; Angel Delchev Angelov; Mityu Rachev Petkov; Simeon Dimitrov Grozev; Kiril Lalev Cavdarov; Gancho Hristov Kadelkov
Original assignee: NPK Elektronna Obrabotka na Materialite I Novi Technologit
Current assignee: NPK Elektronna Obrabotka na Materialite I Novi Technologit
Priority date: 1984-07-10
Filing date: 1985-06-26
Publication date: 1986-01-15
Also published as: GB2161406B; DD267380A7; GB8516131D0; BG39688A1; DE3523239A1; DE3523239C2

Abstract

A machine is adapted to carry outpolishing/finishing action, using a magnetic abrasive medium, on a shafted gear (5) of the type used in hydraulic gear pumps and having a pair of stub shafts projecting one on either side of a gear wheel. The machine comprises a rotatable work table (1) having on its periphery clamping devices (2) each comprising a bracket fixed to the table (1) and supporting upper and lower holders which engage with the ends of the stub shafts to hold the shafted gear (5) in position to be worked on. A plurality of working stations (4, 6, 7, 8) are spaced around the periphery of the work table (1) and the work table (1) is rotatable incrementally to advance the clamping devices (2) from one station to another to enable the series of working actions to be carried out. A driving device anociated with each clamping device (2) includes a drive gear driven by a motor and resiliantly engaged with the shafted gear (5) when the latter is undergoing treatment at one of the working stations. At least one of the working stations (4) is arranged to carry out polishing action on the stub shafts of the shafted gear (5) and comprises pairs of blades which embrace respective stub shafts therebetween, means for magnetising the blades and means for feeding magnetic abrasive medium into the spaces between the blades and the stub shafts. <IMAGE>

Description

SPECIFICATION Polishing machine This invention relates to a polishing machine which is adapted to carry out polishing/finishing action, using a magnetic abrasive medium, on a shafted gear having a pair of stub shafts provided one on either side of a gear wheel. Examples of shafted gear with which the machine may be used include the types of shafted gear or shafted cog wheels for use in hydraulic gear pumps and the like.

It is known to provide a machine for the simultaneous polishing of the throats and fronts e.g the surfaces of the shafts of a shafted gear, and for taking off or blunting the edges thereof. The known machine comprises a non-ferro magnetic body, mounted to which, one next to the other, are ten identical working positions. Each working position comprises a chuck having a front driving support, a movable clamp and a magnetic system. The chuck is equipped with a sinking sub-spring centre, connected to a uni-directional hydraulic cylinder.

The rotation of the chuck is two-directional and is achieved by an electro driving device. Coaxially to the sinking centre is a movable clamping upper centre body, in which a bush is mounted with an opening receiving a MORSE cone, in which is placed a clamping centre. The body is supplied with guides which move along guide bars by means of a hydraulic cylinder. Between the sinking centre and the upper driving centre there is centered a shafted gear wheel, which is rotated by the front driving support so as to have the front and the throat polished.

The magnetic system comprises magnetic core frames which are fixed to the non-ferro magnetic body. At the rear end of each magnetic core there is a winding, mounted on a closing magnetic core of the frame. At the front part of the magnetic cores there are fixed sliding tips, enveloping the shafts of the shafted gear, at a given working pitch therefrom, and to which there is supplied a ferromagnetic abrasive powder. The tips are flat and in the working process during the treatment of the throats, e.g. the surfaces of the shafts, they should have a constant magnetic field with opposite polarity along the fronts of the shafted gear, and similarly concerning the throats. Switching-in of the magnetic field is obtained, when the polarity concerning the throats becomes opposite and identical concerning the fronts. The windings are fed with direct current.

A disadvantage of the known machine is that it is impossible, with one magnetic system, to achieve opposite polarity, first along the throat and then along the front, in order to obtain a magneticabrasive processing, so that the machine can process on the fronts and blunt the sharp edges, but the throats are only rubbed against, with the result that there is resulting roughness of this surface which is very high. Another disadvantage is that imparting rotation along the front of the throat of the shafted gear by the driving support, under great pressure, especially for larger shaft gears, cannot compensate for the resisting moment from the polishing of the fronts and the rounding of the shaft edges, and the support begins to overturn with rapid wearing-away of the supports and of the throat meshing with it.The machine can operate only with weak magnetic fields, which lengthens the time needed for the process and seriously diminishes productivity. Because of the linear arrangement of the working positions upon an immovable plate, the machine cannot be automated and its manipulation requires tedious manual labour for positioning and removing the shafted gears before and after treatment. A disadvantage of the machine is also the lack of any finishing action on the teeth of the gear wheel of the shafted gear such as is usually necessary to remove scale after thermal treatment.

The present invention has been developed primarily, though not exclusively, with a view to providing a polishing machine which can carry out simultaneous polishing of the throats and fronts, and also take-off the sharp edges of shafted gears i.e. shaft-cog wheels, in which the polishing of the throats and the fronts is achieved by magnetic-abrasive processing, with reliable imparting of rotation to the gear wheel of the shafted gear, and allowing the use of strong magnetic fields during processing, and hence high productivity, and also enabling the teeth of the gear wheels to be treated and the machine to be automated.

According to the invention there is provided a polishing machine which is adapted to carry out polishing/finishing action, using a magnetic abrasive medium, on a shafted gear having a pair of stub shafts projecting one on either side of a gear wheel, the machine comprising: a rotatable worktable having at least one clamping device on its periphery which is adapted to hold the shafted gear, said clamping device comprising a bracket fixed to the table, and upper and lower holders mounted on the bracket and arranged to engage with the ends of the stub shafts in order to hold the shafted gear in position ready for a working action thereon; and a plurality of working stations spaced apart around the periphery of the worktable and arranged to provide a series of working actions on the shafted gear, the worktable being rotatable incrementally in order to advance the clamping device from one station to another to enable the series of working actions to be carried out; in which: a driving device is coupled with the clamping device and includes a cradle, a drive gear rotatably mounted on said cradle and engageable drivingly with the gear wheel of said shafted gear when the latter is held by the upper and lower holders and is undergoing working action at one of the working stations, a motor mounted on said cradle and arranged to rotate said drive gear, and means resiliently biasing the cradle towards the bracket so as to urge the drive gear and the gear wheel into mesh; and at least one of the working stations is arranged to carry out polishing action on the stub shafts and comprises first and second pairs of blades which are arranged to embrace respective stub shafts therebetween, means for magnetising the blades, and and means for feeding magnetic medium into the spaces between the blades and the stub shafts.

As will become apparent from later detailed description of a preferred embodiment of the invention, a machine may be provided for simultaneous polishing of the throats, fronts and for blunting the sharp edges of shafted gears e.g. shaft-cog wheels, in which the machine comprises a plate with working positions, upon each of which there is mounted a clamping device, having a bracket carrying an immovable clamp with a lower centre and a movable clamp with an upper centre for holding the shafted gear, as well as a magnetic system, formed by a non-ferro magnetic plate, mounted on which are two non-ferro magnetic bodies, carrying two magnetic cores each. At the rear end of the magnetic cores are mounted windings, and at the front end are mounted sliding plates with tips i.e.

the pairs of blades, and the magnetic cores of each non-ferro magnetic body are connected to a vertical closing magnetic core.

In the preferred embodiment, a cradle is mounted on the bracket of the clamping devices, and the cradle is connected via a bearing to rotate on an axis, and is resiliently supported by a spring which draws the cradle towards the bracket. The cradle carries a hydraulic motor, and upon the shaft of the motor there is mounted a driving gear which meshes with the gear wheel of the shafted gear.The plate carrying the clamping devices is a pitch or indexing plate. The processing of the throats and the fronts of the shafted gear wheel is divided between first, second and third working positions. At the third working position the upper and lower magnetic cores of each non-ferro magnetic body are connected to a closing horizontal core.The windings at the third working position are fed with pulsating rectified current at low frequency, and the small tips for processing the lower part i.e. the lower stub shaft of the shafted gear and the large tips for processing the upper part i.e.

the other stub shaft, and which are magnetically connected to the magnetic cores, have slanted working areas and opposite magnetic polarities.

The advantage of the polishing machine according to the embodiment of the invention-is the achievement of magnetic-abrasive processing along the fronts and throats with use of strong magnetic fields, which provides for low roughness and the required blunting of any sharp edges with high productivity.Another advantage is achievement of abrasion of the teeth of the gear wheel of the shafted gear, along the length thereof, allowing removal of any scale formed during thermal treat menu. the processing of a wide variety of cog wheels can be carried out with a single set of tips.

The mounting of a standard robot to cooperate with the machine allows a full automation of the machine.

One embodiment of polishing machine according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a plan view of the polishing machine; Figure 2 is a longitudinal sectional view of a clamping device provided on a work table of the machine shown in Figure 1; Figure 3 is a side view of the clamping device shown in Figure 2; Figure 4 is a front view of first and second working stations of the- machine; Figure 5 is a cross sectional view of a magnetic system provided at the first working station; Figure 6 is a sectional view taken on the line VI VI in Figure 5; Figure 7 is a front view of the third working station of the machine; and Figure 8 is a sectional view through an upper magnetic system at the third working station shown in Figure 7.

Referring now to the drawings, there will be described in more detail below a polishing machine which is adapted to carry out polishing/finishing action, using a magnetic abrasive medium, on a shafted gear (5) having a pair of stub shafts projecting one on either side of a gear wheel, such shafted gear being of the type particularly for use in hydraulic gear pumps.The machine comprises a rotatable work table 111 having at least one clamping device (2) on its periphery which is adapted to hold the shafted gear (5), the clamping device comprising a bracket (10) fixed to the table (1), and upper and lower holders (11, 12) mounted on the bracket (10) and which engage with the ends of the stub shafts in order to hold the shafted gear (5) in position ready for a working action thereon.A plurality of working stations (4, 6, 7, 8) are spaced apart around the periphery of the work table (1) and are arranged to provide a series of working actions on the shafted gear (5), the work table (1) being rotatable incrementally in order to advance the clamping device (2) from one station to another to enable the series of working actions to be carried out.

A driving device is coupled with the clamping device and includes a cradle (25), a drive gear (23) rotatably mounted on the cradle and engageable drivingly with the gear wheel of the shafted gear (5) when the latter is held by the upper and lower holders (11,12) and is undergoing. treatment at one of the working stations, a motor (24) mounted on the cradle (25) and arranged to rotate the drive gear (23), and means (27) resiliently biasing the cradle (5) towards the bracket (10) so as to urge the drive gear (23) and the -gear wheel (5) into mesh. At least one of the working stations (4) is ar- ranged to carry out polishing action on the stub shafts of the shafted gear and comprises first and second pairs of blades (37, 38) which are arranged to embrace respective stub shafts therebetween, means (31, 32, 33, 34, 35) for magnetising the blades (37, 38) and means (49) for feeding magnetic abrasive medium into the spaces between the blades and the stub shafts.

Thus, as shown in Figure 1, the polishing machine comprises a rotatable pitch or indexing plate 1, on which are mounted six clamping devices 2. A feeding robot 3 serves to feed a shafted gear 5 to the machine, so that the latter can be subjected to a series of working actions by successive working stations spaced apart around the periphery of the work table. The feeding robot 3 comprises a feed arm 3a and a removing arm 3b and a box for tools.

First and second working stations 4 are provided around the periphery of the work table 1, and serve to process the fronts and to blunt any sharp edges on the shafted gear 5, and in particular serve to polish the cylindrical external surface of the stub shafts which project upwardly.and downwardly from a gear wheel thereof. A third working station 6 serves to process the throats of the shafted gear 5, a fourth working station 7 serves to de-magnetise and wash the processed gear 5, and a fifth working station 8 serves for drying. In the centre of the rotating pitch plate 1 there is mounted a central hydraulic distributor 9.

Each clamping device 8 comprises a bracket 10 to the front of which there are mounted a movable holder 11 and a fixed holder 12. Each holder has a bush with an opening which receives a Morse cone 13, on radial axial bearing 14 on a body 15. The bearings 14 are pressed into position by caps 16 and 17. To the bush with an opening having Morse cone 13 of the fixed holder 12 there is placed a lower centre 18, and the body 15, connected to guides 20 is immovably fixed to the bracket 10. In the bush of the movable holder 11 there is placed an upper centre 19, and its body 15 is connected to guides 20, along guide bars 21, fixedly clamped to the bracket 10.The movable holder 11 is driven by a hydraulic cylinder 22, connected to the bracket 10 and to the body 15 of the movable holder 11.

There is provided an opening in bracket 10 through which passes a drive gear 23, which meshes with the gear wheel of the shafted gear 5. Drive gear 23 is mounted upon the shaft of a hydraulic drive motor 24, mounted on cradle 25 to rotate on bearings about axis 26. The gear 23 is urged into mesh with the gear wheel of the shafted gear 5, and is maintained in this position, by resilient biasing spring 27 which interconnects the cradle 25 and the bracket 10.

The first and second working stations 4 each include an hydraulic feed plate 28 (Figure 5) which is mounted on the bracket of the rotating plate 1. On the feed plate 28 there is mounted a non-ferro magnetic plate 29, to which immovably are connected two non-ferro magnetic bodies 30.Two magnetic cores 31 are mounted in openings in the body 30, and have windings 32 which are connected at their rear end with vertical closing magnetic core 33. The windings 32 and the closing magnetic core 33 are covered with a non-ferro magnetic lid 34. At the front part of each magnetic core 31 there are immovably mounted levelling magnetic cores 35.To their front there is pressed, having the possibility of movement, a sliding plate 36 which in its front part, towards the shafted gear 5, carries a pair of small blades or tips 37 for processing the lower throat i.e. the lower stub shaft of the shafted gear 5, and a pair of larger tips or blades 38 for processing the upper throat i.e. the upwardly extending stub shaft of the shafted gear 5. The tips 37 and 38 have flat processing fronts which face the stub shafts, and between which there will be introduced, as described below, magnetic abrasive medium which is used to exert the required polishing/finishing action on the gear component to be treated.

At the rear of the sliding plate 36 there is mounted a plate 39 provided with a screw 40 for horizontal adjustment of the sliding plate 36, the screw 40 being protected by a corrugated safety device 41 and having an operating knob 42. The sliding plate 36 is guided along lateral guides 43, which move along non-ferro magnetic guides 44, mounted on the magnetic cores 31. The guides 43 are mounted on the front non-ferror magnetic plate 45, ending in its upper part with non-ferro magnetic arm 46 in which there is a second screw 40 for vertical adjustment of the sliding plates 36. The screws 40 for the horizontal and vertical adjustments of the sliding plate 36 are connected bearingly in the guides 43 and the magnetic core 31. At the lower part of the front non-ferro magnetic plate 45 there is a non-ferro magnetic safety device 47, ending in a labyrinth joint packing 48.

Between the two non-ferro magnetic bodies 30 there are mounted two hoppers 49 for feeding doses of ferro-magnetic abrasive powder to the working zone of the small tips 37 and the large tips 38, and which are screened from the magnetic systems by means of ferro-magnetic thin sheet iron.

The third working station 6 has a similar arrangement to that just described for the first and second working stations 4, but with the difference that the two magnetic cores 31 from the two nonferro magnetic bodies 30 are connected with horizontal closing non-ferro magnetic cores 50. Also, the small tips 37a for the lower throat of the shafted gear 5 and the larger tips 38a for the upper throat, have slanting fronts to the throats of the shafted gear 5. In that position, the hoppers 49 feed the powder by means of feeding tip devices 51.

At the first and second working stations, the small tips 37 and the large tips 38 are magnetically equal, whereas at the third station they are magnetically opposite.

The fourth working station 7 also comprises hydraulic feeding plate 28, on which is mounted a demagnetising winding 52, which envelops on the working position the immovable holder 11, the movable holder 12 and the gear 5. In the opening of the demagnetising winding 52 there are washing jets 53.

The fifth working station 8 comprises hydraulic feeding plate 28, upon which is mounted a box 54, carrying drying jets, and connected to a source of air under pressure.

During operation of the machine, it is supplied with a cooling medium, which feeds cooling liquid towards the first, second and third workings station for cooling purposes during treatment of the gear components, and towards the fourth working station for washing these parts. The machine is equipped with hydraulic medium, and electrical control panels for controlling each working position. The operation of the machine will now be described.

By means of the screws 4d the tips 37 and 38 can be adjusted at a required working pitch corre sponding to the form of the shafted gear 5, and are fixed to the front non-ferro magnetic plate 45 by bolts. The removing arm 3a of the feeding robot 3 holds the processed shafted gear 5, the hydraulic cylinder 22 lifts the upper centre 19, the removing arm 3a lifts-up and rotates, leaving the gear 5 in the box for the ready parts.At that moment, the feed arm 3b takes the gear 5 from the box, in unpolished and non-blunted form, gives it to the clamping device 2 above the lower centre 18 and places thereon. When placing the gear 5, if the teeth mesh properly with the teeth of the driving gear 23, the cradle 25 is immovable. However, if they do not mesh, the cradle 25 can yield resiliently until such time as proper mesh is achieved.

The hydraulic cylinder 22 lowers the upper centre 19, the gear 5 is centered, the feeding arm 3b is then opened and removed. The rotating pitch plate 1 therefore positions the gear 5 in front of the first working position 4, and the hydraulic feeding plate 28 feeds at a quick and working pace until a support is reached, in which the small tips 37 and the large tips 38 envelop the stub shafts of the gear 5 and stand at a working pitch from them.

The windings 32 are fed with direct-current and there is a constant magnetic field between the tips.

Ferro magnetic abrasive powder is fed to the working zones by means of the hoppers 49, and also a lubricating-cooling liquid. The gear 5-is rotated by means of the driving gear 23, and if there has not been a coincidence of the teeth, they mesh and the cradle 25 returns to the working position by the spring 27.

Polishing is carried out of the fronts and blunting of one side in the evolvent of the teeth of the gear 5. When the time finishes and the hydraulic feed plate 28 returns the first working station 4 to a starting position at a rapid rate. The pitch plate 1 then operates to position the partly treated gear 5 in front of the second working station 4, where the cycle is repeated, but with an opposite direction of rotation of the gear 5 by drive gear 23 for blunting the other evolvent of the teeth.During the processing at the first and second working positions 4, in the space between the teeth of the gear 5 and the driving gear 23 there is received ferro magnetic and abrasive powder, which removes any scale present on the teeth lengthwise, which has been formed during previous thermal treatment.

After the positioning of the rotating plate 1, the gear 5 stands in front of the third working station 6. The working cycle is the same as for the first and second working stations 4, but with the difference that the feeding of the winding 32 is with pulsating rectified current with low frequency, so that on the small tips 37 and the large tips 38 there is a pulsating magnetic field at low frequency, during which is achieved polishing of the throats of the gear 5.

At the fourth working station 7, by means of the hydraulic feeding plate 28 the demagnetising winding 52 is fed to the support.Demagnetisation continues with periodic reaching of maximum and minimum alternating currents and, at the same time, by means of jets of lubricating cooling liquid from the jets 53 there is achieved washing of the parts.

Drying is carried out at the fifth station 8. At the first and second working stations 4, and at the third working station 6 the shafted gear 5 is rotated at high revolutions, whereas at the fourth station 7 and fifth station 8 it is rotated more slowly.

Claims

1. A polishing machine which is adapted to carry out-polishing/finishing action, using a magnetic abrasive medium, on a shafted gear having a pair of stub shafts projecting one on either side of a gear wheel, the-machine comprising: a rotatable worktable having at least one clamping device on its periphery which is adapted to hold the shafted gear, said clamping device comprising a bracket fixed the table, and upper and lower holders mounted on the bracket and arranged to engage with the ends of the stub shafts in order to hold the shafted gear in position ready for a working action thereon; and a plurality of working stations spaced apart around the periphery of the worktable and arranged to provide a series of working actions on the shafted gear, the worktable being rotatable incrementally in order to advance the clamping device from one station to another to enable the series of working actions to be carried out; in which: a driving device is coupled with the clamping device and includes a cradle, a drive gear rotatably mounted on said cradle and engageable drivingly with the gear wheel of said shafted gear when the latter is held by the upper and lower holders and is undergoing working action at one of the working stations, a motor mounted on said cradle and arranged to rotate said drive gear, and means resiliently biasing the cradle towards the bracket so as to urge the drive gear and the gear wheel into mesh; and at least one of the working stations- is arranged to carry out polishing action on the stub shafts and comprises first and second pairs of blades which are arranged to embrace respective stub shafts therebetween, means for magnetising the blades, and means for feeding magnetic abrasive medium into the spaces between the blades and the stub shafts.

2. A machine according to claim 1, in which the means for magnetising the blade comprises magnetic cores having windings thereon.

3. A machine according to claim 1 or 2, in which first and-second working stations are arranged in succession so as to carry out polishing action on the stub shafts of the shafted gear, the gear wheel being rotatable by said drive gear in one direction at one of the stations and in the opposite direction at the other of the stations.

4. A machine according to claim 3, in which the first and second pairs of blades are spaced apart from each other in order to define a space in which the gear wheel of the shafted gear can be received.

5. A machine according to claim 4, in which a third working station is arranged to polish the stub shafts of the shafted gear, and also include means for directing the magnetic abrasive medium to the teeth of the gear wheel of the shafted gear.

6. A machine according to claim 4 or 5, in which the means for magnetising the blades at the third working station comprises upper and lower magnetic cores mounted on a non-ferro magnetic body and connected to a closing horizontal magnetic core, and in which the windings at the third working station are arranged to be fed with pulsating rectified current at low frequency, and the first and second pair of blades are arranged to have slanting working areas and to have opposing magnetic polarity.

7. A machine according to any one of the preceding claims, in which said means for resiliently biasing the cradle towards the bracket comprises a tension spring.

8. A machine according to any one of the preceding claims, in which the working stations include a demagnetising and washing station and a drying station.

9. A machine according to claim 1 and substantially as hereinbefore described, with reference to, and as shown in the accompanying drawings.