EP0882549A1 - Belt grinding machine for cylindrical shaft bearings - Google Patents

Abstract

The machine consists of two jaws (5) on pivoted arms (1), each with two concave surfaces (6a,6b) of different diameters which are lined with the abrasive strip. The arms are connected to a support (2) which is moved by a hydraulic power cylinder (7) between two positions, in each of which the two jaws close on a shaft journal of one diameter or another. In between machining cycles the abrasive strip is renewed by winding it from one reel (10) to another (11).

Description

The present invention relates to a machining machine by abrasive belt of cylindrical bearings of shafts, in particular of journals camshafts or journals and / or crankshaft crankpins.

Known machines of this type include, for machining of each bearing of the shaft which is rotated around its axis during machining, two arms pivotally mounted in a plane on the same support. Two opposite jaws are mounted on said arms and each have a concave shaped application surface of cylinder segment with a diameter corresponding to the diameter of the worn to machine. Guiding means are provided for passing the abrasive strip facing the application surfaces of the two jaws. Arm operating means make it possible to apply the abrasive belt by the concave surfaces of the jaws in opposition against the surface to be machined.

Known machines of this type are adjusted for machining litters on identical trees. However, it happens more and more in the construction of automobile engines that a single architecture of motors is available in several models or types which can be distinguish for example by different powers. In this case, it is common that for example crankshafts of different models or engine types have the same length, the same number of pins and the same number of crankpins, but differ for example by different diameters of the journals and / or crank pins. Nowadays, the abrasive belt machining of these or crankshafts requires either a machine reserved for crankshafts of each type or model of engine, i.e. stopping the machine and change of the jaws with each passage of a crankshaft of a type or model to another. The same problem arises when machining camshaft journals.

On the contrary, it would be desirable to be able to pass from machining by abrasive belt of the camshaft or crankshaft spans of a type or model to another on the same machining machine, without having to stop the latter to change the jaws for adaptation concave surfaces for applying abrasive tape to diameters different from the ranges to be machined.

The present invention specifically relates to a machining machine allowing this result to be obtained in a simple manner, provided minimum additional cost.

On the abrasive belt machining machine according to the invention, at least first and second application surfaces concaves of different diameters are mounted in opposition in the minus two different positions on the arms so that the band abrasive passes opposite the concave surfaces of the two jaws. The support is movable between at least two positions such as in one from said positions the first concave surfaces of a first diameter can apply the abrasive strip against a diameter span corresponding to a first tree and that in the other of said positions, the second concave surfaces of a second diameter can apply the abrasive belt against a bearing of corresponding diameter of a second tree.

It is thus possible, by a simple change of position of the support of the arms carrying the jaws, to pass instantly, without no other intervention, from the machining of the spans of a first shaft type or model when machining corresponding spans, diameter different, from a tree of another type or model.

In the context of the invention, the jaws mounted on the arms can be either multiple jaws each presenting at at least two concave application surfaces of different diameters, either single jaws, in which case at least two simple jaws having concave surfaces of different diameters are mounted in different positions on each arm.

la figure 1 est une vue d'ensemble d'une unité d'usinage de la machine d'usinage conforme à l'invention, montrant le support, les deux bras pivotants portant chacun une mâchoire double, et les moyens de manoeuvre des deux bras, les mâchoires étant ouvertes, avant fermeture sur une portée d'arbre d'un premier diamètre ;

la figure 2 représente l'ensemble de la figure 1, après fermeture des mâchoires sur la portée à usiner ;

la figure 3 représente la même situation que la figure 2, à plus grande échelle ;

la figure 4 est une coupe suivant IV-IV de la figure 3.

la figure 5 est une vue correspondant à celle de la figure 1, avant fermeture des mâchoires sur une deuxième portée ;

la figure 6 représente l'ensemble de la figure 4 après fermeture des mâchoires ;

la figure 7 représente à plus grande échelle la même situation que la figure 6 ;

Referring to the accompanying drawings, there will be described below in more detail an illustrative and non-limiting embodiment of the machine according to the invention; on the drawings:

Figure 1 is an overall view of a machining unit of the machining machine according to the invention, showing the support, the two pivoting arms each carrying a double jaw, and the means for operating the two arms , the jaws being open, before closing on a shaft bearing of a first diameter;

2 shows the assembly of Figure 1, after closing the jaws on the surface to be machined;

Figure 3 shows the same situation as Figure 2, on a larger scale;

FIG. 4 is a section on IV-IV of FIG. 3.

Figure 5 is a view corresponding to that of Figure 1, before closing the jaws on a second bearing;

Figure 6 shows the assembly of Figure 4 after closing the jaws;

Figure 7 shows on a larger scale the same situation as Figure 6;

The abrasive belt machine as illustrated by the drawings constitute for example a machine for superfinishing spans cylindrical of shafts, in particular of camshaft trunnions or crank pins and / or crankshaft journals. She understands, for the machining of each bearing of the shaft, a pair of arms 1 in opposition mounted on a common support 2 so that the two arms coupled by gears can rotate around axes 3 under the action maneuvering means 4 constituted by a fluid cylinder. Each arm 1 door, at its free lower end, on its inner side, facing the opposite arm, a double jaw 5 comprising two concave surfaces 6a, 6b in the form of cylinder segments of which the parallel axes are spaced from each other along the length of the arm 1.

The support 2 common to the two arms 1 is vertically movable under the action of a fluid cylinder 7 whose stroke is defined by so as to bring the choice of application surfaces 6a or 6b of the two jaws 5 on either side of the bearing 8 to be machined from the shaft which can be held between centers and rotated around of its axis, as is well known in the field of machining by abrasive bearing of trees.

The concave surfaces 6a of the two jaws 5 have a radius of curvature corresponding to the radius of curvature of a first bearing 8a and illustrated in FIGS. 1 to 3 and the concave surfaces 6b jaws 5 corresponding to the radius of a second bearing 8b illustrated in Figures 5 to 7, the two rays being different. In the example illustrated, the radius of curvature of surfaces 6a (therefore the radius of the range 8a) is greater than the radius of the surfaces 6b (therefore the radius of litter 8b).

An abrasive belt 9 is in a manner known per se advanced, between two successive machining cycles, of a reserve coil 10 on a winding reel 11 being guided at the level of the jaws 5 so as to pass opposite the two concave surfaces 6a, 6b of each jaw 5.

According to Figures 1 to 3, the support 2, the arms 1 and the jaws 5 are in the low position, position in which the surfaces concaves 6a of the jaws 5 are located on either side of a span 8a to be machined, bearing whose radius corresponds to the radius of curvature surfaces 6a. Thus, when clamping the jaws 5 under the action of the cylinder 4, the concave surfaces 6a of the jaws 5 apply the strip abrasive 9 against the bearing 8a.

On the contrary, according to Figures 5 to 7, the jaws 5 are are in the high position, position in which the concave surfaces 6b jaws 5 are located on either side of a span 8b whose radius corresponds to the radius of curvature of surfaces 6b, so that when tightening the jaws 5, the concave surfaces 6b of the jaws 5 apply the abrasive band 9 against the surface 8b.

It is therefore possible, on the same strip machining machine abrasive, to instantly switch from machining to a surface 8a of a first diameter of a first shaft for machining a bearing 8b of a second diameter of a second tree, and vice versa, without intervention other than a change in position of the jaws 5, obtained by cylinder control 7.

In Figure 4, we recognize that the concave surface 6b (all as the concave surface 6a) of each jaw 5 is defined not not directly by the metal jaw 5, but by a gasket in coating 12 made of a more flexible material, for example polyurethane, which is attached to the jaw 5 to allow distribution smoother application pressure 9 against the surface to be machined.

It should also be noted that in the context of the invention, the number of concave surfaces for applying abrasive tape of different spokes carried by each arm 1 could be greater at 2, the jack 7 allowing in this case to bring the jaws 5 in more than two different positions, which would allow machining, on the same machine, more than two spans of different diameters.

Finally, there is shown in dashes in FIG. 7 that each jaw 5, instead of being a multiple jaw, in this case a jaw double with two concave application surfaces of different spokes, could be composed of two simple jaws 5a, 5b each having an application surface, the two jaws 5a and 5b of each arm 1 having concave surfaces of spokes and being mounted in different positions on the arm 1.

Claims (3)

Machine for abrasive belt machining of cylindrical bearing surfaces of shafts, in particular of camshaft journals or journals and / or crankshaft pins, comprising for the machining of each bearing of the shaft driven in rotation around its axis. two arms pivotally mounted in a plane on the same support, two opposite jaws mounted on said arms and having concave application surfaces in the form of a cylinder segment with a diameter corresponding to the diameter of the bearing surface to be machined, guide means for passing an abrasive strip opposite the application surfaces of the jaws, and means for maneuvering the arms to apply the abrasive strip through the concave surfaces of the jaws in opposition against the surface to be machined, characterized in that at least first and second concave application surfaces (6a, 6b) of different diameters are mounted in opposition in at least two different positions on the arms (1) so that the abrasive strip (9 ) passes opposite the concave surfaces (6a, 6b) of the two jaws (5) and that the support (2) of the arms is movable between at least two positions such that in one of said positions the first concave surfaces (6a) d '' a first diameter of the jaws can apply the abrasive strip (9) against a bearing (8a) of corresponding diameter of a first shaft and that in the other of said positions, the concave surfaces (6b) of a second diameter of the jaws can apply the abrasive strip (9) against a surface (8b) of corresponding diameter of a second shaft. Machine according to claim 1, characterized in that that the jaws are multiple jaws (5) each having at least two concave application surfaces (6a, 6b) of diameters different. Machine according to claim 1, characterized in that that the jaws are simple jaws (5a, 5b) and that at least two simple jaws (5a, 5b) have application surfaces concaves (6a, 6b) of different diameters are mounted in positions different on each arm (1).

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