FR2575956A1 - MAGNETO-ABRASIVE MACHINING DEVICE FOR EXTERIOR CYLINDRICAL SURFACES - Google Patents

Abstract

THE INVENTION RELATES TO ABRASION MACHINING. THE DEVICE WHICH IS THE SUBJECT OF THE INVENTION IS OF THE TYPE INCLUDING A MECHANISM ROTATING THE PART, AN ELECTROMAGNETIC SYSTEM 1 PROVIDED WITH POLAR EXPANSIONS 2 AND 3 THAT CAN SLIDE WITH RESPECT TO MAGNETIC CIRCUIT 6 IN GUIDANCE 7, 8 THANKS TO ROLLERS 9, 10, AND A MECHANISM 4 PUTTING THE POLAR FLOWERS IN OSCILLATION AND ACTUATED BY A DRIVE 5, AND IS CHARACTERIZED IN THAT THE OSCILLATION MECHANISM 3 IS EXECUTED IN THE FORM OF A SHAFT 13 BEARING SOCKETS ECCENTRICS OFFSET BY 180 ONE 14 WITH RESPECT TO THE OTHER 15 AND ON WHICH ARE MOUNTED THE POLAR EXPANSIONS 2 AND 3 RESPECTIVELY. THE INVENTION FINDS ITS MOST ADVANTAGEOUS APPLICATIONS, ESPECIALLY IN HEAVY-DUTY MECHANICAL CONSTRUCTIONS AND THE CONSTRUCTION OF MACHINES FOR THE CHEMICAL AND FOOD INDUSTRIES.

Description

The present invention relates to the field of machining parts by

  abrasion and particularly relates to a magneto-abrasive machining device

  outer cylindrical surfaces.

  The invention finds its most advantageous applications in particular in heavy mechanical constructions and the construction of machines for

  the chemical and food industries, for the polis-

  magneto-abrasive processing of large rolling mills, paper machines, mixing machines and other machines.

  A magneto-machining device is known

  abrasive outer cylindrical surfaces of large diameter parts (see the book by Baron Ju.M. "The technology of abrasive machining in a magnetic field", L., "Mashinostroenie, 1975, page 50).

  has a mechanism that rotates the workpiece

  an electro-magnetic system capable of

  and a mechanism for imparting oscillations to the electromagnetic and

a drive member.

  The disadvantage of this known device lies

  in that the drive member of the electronic system

  Magnetic and the pair of polar spurs are executed in one piece. However, it is difficult

  to put the electromagnetic system, whose dimensions

  sions and mass are considerable, moving

  latoire. The oscillation mechanism and its driving organ

  are massive and provide only synchronous oscillations of polar expansions. Therefore, it is impossible to ensure, during the magneto-abrasive machining, the non-repetition of the traces on the workpiece surface of the workpiece. This is the cause of the low quality indices

  and machining efficiency. In this device, the sur-

  active faces of the pole shoes are of cylindrical shape, concentric with the surface to be machined by the

  piece. With such a shape of the active surfaces, the

  The machining interval between the workpiece and the pole shoes has a regular section along its entire length, and this is why the magnetic field is also regularly distributed along said interval. It is known, however, that the abrasive powder moves, during the machining process, towards the output of the machining gap. It follows that, in the case of a regular section of the machining gap, a significant portion of the magnetic powder does not participate in the useful work, which results in a significant decrease in the renoement

  and the quality of magneto-abrasive machining.

  In the known device, the pole shoes mounted on one side of the workpiece and biased by magnetic forces can cause deformation of the workpiece. For this reason, it is

  difficult to use this device for magneto-

abrasive of slightly rigid parts.

  It was therefore proposed to develop a

  magneto-abrasive machining device for cylindrical surfaces

  exterior of a room, dimensions and

  which would be reduced, which would make it possible

  optimally the rotational movement of the workpiece and the oscillations of the pole shoes and give the possibility of machining large

  parts, while at the same time improving substantially the

  and the quality of magneto-abrasive machining.

  The problem thus posed is solved by means of a

  magneto-abrasive machining device for cylindrical surfaces

  exterior of a room, with a mechanism

  rotating the workpiece, an electronic system

  magnet with polar spurs and a mechanism

  putting the polar unfoldings in motion oscil-

  The invention is characterized in that the mechanism for setting the polar spurs into oscillation is executed in the form of a shaft provided with eccentric bushings that are offset relative to one another. another -180, a pole shoe being seated on each of said sleeves. Thanks to the fact that the polar unfoldings

  are executed as separate elements of the cir-

  the magnetic system of the electromagnetic system

  sitive, we no longer need to set the entire electromagnetic system in oscillation. The oscillations are communicated only to the polar unfoldings. Mounting the pair of pole shoes on the drive shaft carrying the eccentric bushings offset from each other by 180 makes it possible to oscillate the polar bearings in phase opposition with respect to each other. the other, which

  is necessary to prevent the coincidence of

  their movements and, consequently, the training

  machining traces on the surface to be machined.

  It is advantageous that the device is provided with a pair of additional pole shoes with a mechanism for their oscillation, this additional pair of pole shoes being mounted in opposition to the main pair on the other side of the piece. to machine. Since in the case where a pair of pole shoes is arranged on one side of the workpiece, forces are created.

  magnetic attraction between the room and the

  Polar footings can be drawn to the surface of the piece if stiffness

  of the workpiece or device is not sufficient.

  As a result, irreparable defects such as deep lines and scratches may form on the surface to be machined. By mounting said additional pair

  polar fulfillment, the forces of attrac-

  between the pole openings of the device and the workpiece, their deformations are reduced and the possibility of machining

not rigid parts.

  It is possible that the polar openings are made with planar active surfaces and forming, in each pair, an angle of

  at 180. When the active surfaces of flowering

  polar formations have such a shape, the section of

  the gap between the workpiece and the

  polar events is variable. The magnetic flux is

  concentrates then in the smallest section of the inter-

  machining zone in which the ferromagnetic abrasive powder is retained. As a result, the form of application of the powder against the surface of the part increases, which increases the efficiency and the quality of the machining. When the value of the angle "is less than 100, the length of the part of the surface of the part surrounded by the pair of polar expansions

  and through which closes the magnetic flux, grows.

  As a result, the value of magnetic induction in

  machining intervals decrease and the performance of the machining

swimming down.

  The invention will be better understood and other purposes, details and advantages thereof will become more apparent

  reading the detailed explanatory description that will

  follow various embodiments given only by way of non-limiting examples, with references to the accompanying non-limiting drawings in which: - Figure 1 represents the schematic diagram

  a magneto-abrasive machining device for cylindrical surfaces

  external dies according to the invention, in cross section.

  partial versale; - Figure 2 is a section along II-II of the figure; FIG. 3 represents the block diagram of the device according to the invention, provided with an additional pair of pole shoes, mounted in

  look at the main pair, on the other side of the room.

  The proposed device for magneto-abrasive machining of the outer cylindrical surfaces of a part,

  as shown in FIGS. 1 and 2, is intended to

  born to the machining of hollow parts of the roll type

black.

  The device comprises a rotational mechanism

  the workpiece, for example a mechanism executed in the form of a mandrel with three jaws (not shown) of a lathe, an electromagnetic system 1 provided with expansions

  2 and 3, and a mechanism 4 for oscillating

  polar movements, commanded by a training body

5.

  The electromagnetic system 1 comprises a

  magnetic circuit 6 at the ends of which are mounted, in guides 7 and 8, pole shoes 2 and 3, respectively. Bearings 9 and 10 are housed between the faces of the polar shoes 2 and 3 and the

  6. The drive member 5 of the drive

  The oscillation mechanism of the pole shoes 2 and 3 comprises an electric motor 11 and a belt transmission 12. The mechanism for advancing the magnetic system along the axis of the workpiece (not shown) can

  for example, in the form of a long-distance

  tudinal turn, with its drive member.

  According to the invention, the mechanism 4 putting the pole shoes 2 and 3 in oscillation is executed in the form of a shaft 13 carrying eccentric bushings 14 and 15 offset from each other by 180 and

  wedged on the shaft 13 by keyways 16 and 17, respec-

  tively. Each of the polar footprints 2, 3 is

  on a bushing 14, 15, respectively. The blossoms

  Polar elements 2 and 3 form, with the workpiece 18, machining intervals 19 and 20 in which an abrasive ferromagnetic powder (not shown) is housed. The pole shoes 2 and 3 have active surfaces 21 and 22 planes, as shown in Figure 1, and forming an angle between them

  from 100 to 180. The active surfaces 21 and 22 of the

  polar nips 2 and 3 may be cylindrical and concentric with respect to the surface to be machined.

the room 18.

  As shown in FIG. 3, the claimed device may comprise an additional electromagnetic system 23 comprising a pair of polar extensions 24 and 25 and a mechanism 23 for creating

oscillation.

  The additional electromagnetic system 23 is mounted on the other side of the workpiece 18,

  in opposition to the electromagnetic system-

  1, and makes it possible to equalize the magnetic attraction forces between the pole shoes 24 and 25 and the part 18. The pole shoes have active surfaces 27 and 28, respectively, which are flat and form between them, in each pair ,a

O angle from 100 to 180.

  The claimed device operates as follows. The rotation of the electric motor 11 of

  the driving member 5 is transmitted by the transmi-

  12 to the shaft 13 and to the eccentric bushings 14 and 15 of the mechanism 4 producing the oscillations. When the eccentric bushings 14 and 15 are rotated, the pole shoes 2 and 3 fitted on them oscillate in the guides 7 and 8. The rotation mechanism of the workpiece rotates it about its axis at a distance from its axis. angular velocity X. The abrasive ferromagnetic powder (not shown) is poured into the machining intervals 19 and 20

  between the workpiece 18 and the self-expanding

  lar. The powder oscillates at the same time as the pole shoes 2 and 3 and is applied by the magnetic forces, induced in the electromagnetic system, against the surface of the piece

18 in rotation, and the polit.

  Thanks to the flat shape of the active surfaces

  21 and 22 of the polar expansions 2 and 3, the induc-

  Magnetic density is higher in the mini-sections.

  machining intervals 19 and 20, where the abrasive ferromagnetic powder accumulates and becomes more compact. It follows that use. of planar surface active polar bearings in the claimed device allows to use to a greater extent the magnetic flux in the machining intervals and to increase the force of application of the powder against the

  surface of the workpiece, which improves the efficiency

and the quality of the machining.

  The presence of the additional electromagnetic system

  23 with its pole shoes 24 and 25 ensures, during the induction of the magnetic flux in the electromagnetic system 23, the appearance of attractive forces between the piece 18 and the pole shoes 24 and 25. Ultimately, the forces of attraction between the piece 18 and the polar expansions 2 and 3 (or 24 and 25) are balanced, which reduces the deformation

  of Exhibit 18 and, as a result, enables us to

  magneto-abrasive swimming of hollow trees.

  The device makes it possible to substantially increase the polishing efficiency of the outer cylindrical surfaces of large parts, for example rolls of rolling mills, paper machine shafts, crystallizer drums of machines used in the chemical, food and production of polymers, and to ensure at the same time a low roughness of the machined surfacecharacterized

by Ra = 0.04 to 0.01 micron.

Claims (3)

R E V E N D I C A T I 0 N S   1.- Magneto-abrasive machining device for the outer cylindrical surfaces of a workpiece, of the type comprising a mechanism setting the workpiece in rotation, an electromagnetic system (1) provided with pole shoeings (2 and 3) and a mechanism   (4) putting the polar unfoldments in an oscil-   and actuated by a drive member (5), characterized in that the oscillation mechanism (3) is in the form of a shaft (13) carrying eccentric bushings offset by 180 (14) by relative to the other (15) and on which are mounted the pole shoes - (2 and 3), respectively. 2.- Device according to claim 1,   characterized in that it comprises an electronic system   additional magnet (23) also comprising a pair of pole shoes (24 and 25) and provided with its own oscillation mechanism (26) thereof, which system is mounted in opposition to the system electromagnetic (1).   3.- Device according to one of the claims   1 and 2, characterized in that in each pair of pole shoes (2 and 3), (24 and 25), the respective active surfaces (21 and 22), (27 and 28) of these planes and form between them an angle " from 100 to 180.