FR2654969A1 - METHOD FOR LODING BORES IN WORKPIECES, AND MACHINE FOR IMPLEMENTING THIS METHOD. - Google Patents

Abstract

Method and machine for lapping bores on parts, the bores being subjected successively to roughing by lapping for expansion and to finishing by progressive lapping. The machine comprises two parallel roughing lines (2, 3) each having an expansion lapping unit (12, 15) with one spindle (13, 16), a finishing line (4) including a progressive lapping unit ( 18) with for example three pins (19, 20, 21), and carriers (5, 6, 7, 8, 10, 11) independent.

Description

The present invention relates to a method for running in bores in

  parts, as well as a machine for setting up

work of this process.

  Lapping (called "honing" in Anglo-Saxon literature) of bores is carried out at present, either according to the lapping process known as by expansion, or according to the lapping process said

progressive.

  Lapping by expansion consists in introducing, into the bore to be lapped, an expansion lapping machine animated with a rotary movement and an oscillating movement back and forth along the axis of rotation and in increasing the diameter of the lapping during lapping This expansion is therefore comparable to the advance movement that a tool undergoes during machining operations such as grinding. The main advantage of lapping by expansion consists in the fact that it allows, thanks to the lapping expansion during running in, removing a

  comparatively large amount of material in one pass.

  The main drawback of lapping by expansion is that a coarse abrasive expansion lapping as necessary to obtain a large stock removal in one pass only allows relatively low accuracy and

  especially a relatively poor surface finish.

  This is the reason why it has already been proposed to subject bores to two lapping passes by expansion, the first pass constituting a roughing being carried out using a coarse abrasive expansion lapping machine and the second pass constituting a finish carried out using a fine-grain abrasive lapper However, this second finish pass does not always make it possible to obtain the necessary precision and surface condition. The progressive lapping consists in making a lapping of a fixed diameter, animated by a movement of a rotation around its axis,

  a single back and forth movement (back and forth) in a bore.

  Since the quantity of material removed on each pass is small, it is necessary, when the total quantity of material to be removed is large, to subject each bore to a relatively large number of progressive lapping passes using a relatively number important of successive lappers having increasingly fine grains This progressive lapping makes it possible to obtain a high precision and a good surface condition, but this by means of the implementation of a large number of lappers when the quantity of material to be removed is important Each of these progressive lappers must be adjusted with precision, so that the adjustment time of a machine

  progressive lapping comprising a large number of lapping is long.

  In addition, the cost price and the size of the lapping machine

  increases with the number of laps.

  The present invention relates to a lapping process for bores meeting the two requirements of high precision and significant removal of material The invention also relates to a machine with a relatively simple and compact structure and a reduced cost price allowing precision lapping, with reduced setting times, on bores requiring removal

important material.

  According to the process according to the invention of lapping of bores in parts, each bore is subjected successively to a roughing by lapping by expansion followed by a finishing by progressive lapping. In the context of the invention, the roughing can include one or two lapping passes by expansion and the finishing can include

  minus two progressive lapping passes.

  The machine according to the invention for lapping bore in parts comprises at least one spindle for expansion by lapping, at least two spindles for progressive lapping, and means for bringing each part successively to the spindle for expansion by lapping and each of the progressive lapping pins. In general, a progressive running-in pass requires a time which is substantially half that of an expansion running-in pass. This is the reason why the machine according to the invention can advantageously comprise two parallel lines. lapping by expansion and a single progressive lapping line, means being provided for bringing to the single progressive lapping line the blanks coming from both

  of the two lapping lines by expansion.

  According to a preferred embodiment of the invention, the single progressive lapping line and each of the two expansion lapping lines are provided with independent feed conveyors for the parts, the machine is supplied with parts by the conveyor a first of the two lapping lines by expansion, the progressive lapping line is arranged downstream of the second lapping line by expansion, and two independent shuttle carriers are arranged between the two lapping lines by expansion, upstream and

downstream of these.

  Preferably, a waste reception line also served by the downstream shuttle transporter is arranged downstream of the

  first lapping line by expansion.

  Referring to the accompanying schematic drawings, an illustrative and nonlimiting embodiment of the subject of the invention will be described below in more detail; in the drawings: FIGS. 1 and 2 show, one in side view and the other in plan, a lapping machine according to the invention

  combining expansion lapping and progressive lapping.

  The lapping machine as illustrated in FIGS. 1 and 2 comprises, on a common frame 1, a first line 2 of lapping by expansion, a second line 3 of lapping by expansion and a line

4 progressive break-in.

  The two lines 2, 3 for lapping by parallel expansion are each served by a conveyor 5, 6, the supply of the machine with the lapping part being effected by the conveyor 5 serving line 2 The line 4 for progressive lapping is served by a transporter 7 which is downstream and in the extension

  of the conveyor 6 of the second line 3 of lapping by expansion.

  It is also by the transporter 7 that the evacuation of the

lapped machine parts.

  A waste reception line 8 is served by a transporter 9 mounted downstream and in the extension of the transporter 5. A first shuttle transporter 10 is arranged upstream of the two

  lines 2, 3 of lapping by expansion and a second conveyor

  shuttle 11 is disposed downstream of the two lines 2, 3 of lapping by expansion, that is to say also upstream of the line 4 of lapping

  progressive and waste reception line 8.

  It should be noted that carriers 5, 6, 7, 9, 10 and 11 are

independent carriers.

  The first line of lapping by expansion comprises a lapping unit 12 with a single spindle 13 of lapping by expansion, the lapping unit 12 being followed by a control unit 8 on 14 Similarly, the second line 3 of expansion lapping comprises a lapping unit 15 with a single expansion lapping pin 16, the lapping unit 15 being followed by a control unit

17.

  The progressive lapping line 4 comprises a lapping unit 18 with three pins 19, 20, 21 of progressive lapping including the laps

  are filled with abrasive grains of increasing finesse.

  The combination, on a single machine, of lapping by expansion and progressive lapping allows, by means of a reduced number of lapping, to operate precision lapping on bores having initially wide tolerances, lapping by expansion providing a roughing followed by '' a progressive lapping with a

reduced number of laps.

  The parallel arrangement of two lapping lines by expansion, the provision of independent carriers for each

  break-in lines, and the provision of two carriers-

  shuttles, one upstream and the other downstream of the two lapping lines by expansion, allows the two roughing lines by expansion lapping to be optimally supplied with workpieces and, after roughing, for routing the parts roughed out, according to their state, either on the single finishing line 4 by progressive lapping

  either on line 8 for receiving scrap.

  Of course, the invention is not limited to the embodiments shown and described. It would thus be possible, within the framework of the invention, to subject each bore to more than one roughing pass by lapping by expansion and / or to provide a finish comprising a number of progressive lapping passes other than

three.

  Furthermore, the invention is also applicable to lapping machines comprising a single roughing line by expansion lapping and / or more than one finishing line by progressive lapping, although the arrangement shown and described constitutes a solution. preferred from a performance perspective, given the times

  different from expansion lapping and progressive lapping.

Claims (4)

  1 Lapping process for bores in parts, characterized in that one successively proceeds on each bore to roughing by lapping by expansion followed by finishing by progressive lapping. 2 Method according to claim 1, characterized in that the roughing comprises one or more lapping passes by expansion. 3 Method according to claim 1, characterized in that   that the finish includes at least two progressive lapping passes.   4 Machine for implementing the method according to claim 1, characterized in that it comprises at least one expansion lapping pin (13, 16), at least two progressive lapping pins (19, 20, 21) , and means (5, 6, 7, 10, 11) for bringing each part successively to the lapping spindle by   expansion and to each of said progressive break-in pins.   Machine according to claim 4, characterized in that it comprises two parallel lines (2, 3) of lapping by expansion and a line (4) of progressive lapping, and means for feeding the parts of one and the other of the two running-in lines   by expansion to the progressive running-in line.   6 Machine according to claim 5, characterized in that the line (4) of progressive lapping is arranged downstream and in the extension of one (3) of the two lines (2, 3) of lapping by expansion, that each lapping lines (2, 3, 4) is provided with an independent advancement conveyor (5, 6, 7), and that two independent shuttle transporters (10, 11) are arranged between the two lines (2, 3) lapping by expansion, upstream and downstream of these last.   7 Installation according to claim 6, characterized in that a line (8) for receiving scrap is disposed downstream and in the extension of the other line (2) of lapping by expansion, this scrap receiving line being also served by the shuttle transporter (11) located downstream of the running-in lines (2, 3) by expansion.