GB2145947A - Method of manufacturing a component part, and more particularly a rolling bearing race ring, provided with a split gap - Google Patents

Abstract

A homogeneously hardened or depth hardened component part is formed with a split gap. In order to obviate time- and cost-intensive metal cutting operations that serve for influencing the path of the split gap, prior to the splitting operation, one of the surfaces (4) of the component part (1) is subjected, at least along a part of the intended path (5) of the split gap and within confined limits transversely thereto, to the action of an energy-rich radiation such as a laser beam or electron beam. Tensile stress, to cause splitting, is provided by a punch (3). For a peripheral split, a groove may extend for part of the intended splitting path, with radiation applied in the groove. A wedge splitter is used against groove side walls. <IMAGE>

Description

SPECIFICATION Method of manufacturing a component part, and more particularly a rolling bearing race ring, provided with a split gap The invention relates to a method of manufacturing a homogeneously hardened component part, and more particularly a rolling bearing race ring, provided with a split gap.

Such component parts are often used, for example, when particular assembly operations either cannot be carried out or only with difficulty with a component part having no split gap. Typical of such component parts are, for example, rolling bearing race rings which are formed with a split gap at one or more positions on their circumference or along their length. They are necessary inter alia, in cases where it is impossible, during the assembly of a rolling bearing, to fill the latterwith rolling bodies in the customary manner. Further typical examples of such component parts are rolling bearing race rings which are formed with split gaps at two positions on their circumference. They are necessary when as, for example, on the case of crank-pin bearings, it is impossible to assemble an unsplit race ring.In most applications, it is necessary with split bearing race rings, just as with any other component parts formed with a split gap, that the split gap should extend along a precisely defined path.

A method of manufacturing race rings formed with split gaps at positions on their circumference is known from DE-PS 27 23 928, in which it is detrimentally necessary, in order to influence the path of the split gap, to carry out expensive metal cutting operations, such as, for example, the boring of holes and the formation of extremely sharpedged grooves in one of the surfaces of the race ring. Moreover, this method is not suitable for the production of race rings having split gaps at positions along their length.

A method of manufacturing race rings having split gaps at positions along their length is known from US-PS 35 86 396. This method has all the abovementioned disadvantages and for its part is unsuitableforthe production of race rings having split gaps at positions on their circumference.

Finally, a method of manufacturing race rings having split gaps at positions on their circumference is known from DE-PS 23 27 which method has as its aim to avoid the disadvantages of the abovementioned known method, so far as influencing the path of the split gap by means of cutting procedures is concerned, by influencing the path of the split gap in an unnotched race ring by introducing the force required to form the split gap into the race ring at force application points which are selected in a suitable manner.

It has, however, become clearthatthis method only works with a sufficiently small proportion of rejects when, in addition to the path of the split gap being influenced by the choice of the points at which force is applied, the ring is formed with a groove or grooves by means of a cutting operation: All the above-mentioned methods are moreover only suitable for the manufacture of component parts other than rolling bearing race rings.

The invention has for its object to provide a method of the kind referred to above which, without increasing the rejection rate, obviates the disadvantage of the known method of influencing the path of the split gap by time and cost-intensive cutting procedures, is suitable for the manufacture of component parts of any kind and is also suitable, so far as rolling bearing race rings are concerned, for producing such race rings with split gaps formed at positions on their circumference as well as for producing such race rings with split gaps formed at positions along their longitudinal extent.

According to the invention this object is attained in that, prior to the splitting operation, one of the surfaces of the component part is subjected, at least along a part of the proposed path of the split gap and within confined limits transversely thereto, to the action of an energy-rich radiation.

Due to the action of an energy-rich radiation, a change of structure is produced in that region of the surface of the component part which is acted upon, and this change of structure is accompanied by a marked surface hardening of the material, so that the component part becomes locally extremely brittle and consequently a preferred location of fracture is provided for the formation of the split gap.

If there are special requirements as to the path of the split gap (for example, if in the case of rolling bearing race rings, this path is to be V-shaped), it is necessary that the corresponding surface of the component path should be acted upon by the energy-rich radiation along the entire intended path of the split gap.

For cases in which there are no special requirements in regard to the path of the split gap, it is sufficient for the surface of the component part to be acted upon by the radiation only along a part of the intended path of the split gap, for example at the starting point thereof.

Particularly good results are obtained with the method according to the invention when, according to an embodiment thereof, the energy-rich radiation which acts on the component part is in the form of a laser-bean, Other kinds of radiation, e.g. electron beam radiation, may however be utilized instead.

A particularly small amount of force is required for splitting the component part when, according to a variant of the invention, the surfaces which are acted on by the radiation are subjected, by the force applied to the component part for forming a split gap in the same, to tensile stress in the irradiated region thereof.

In order to facilitate the application of a tool which may be necessary for exerting on the component part the force required for forming a split gap in the latter, it is proposed according to a further form of the invention that the surface which is acted on by the radiation should be formed with a groove at least along a part of the intended path of the split gap and that the base of this groove should be acted on by the radiation. Since this groove does not serve for influencing the path of the split gap, it is, unlike the known method, unnecessary for it to be formed as a sharp-edged depression.

The advantage of the method according to the invention as compared with the known method thus consists in the fact that it makes possible the production of any desired component parts provided with a split gap, and more particularly the production of race rings formed with split gaps at positions on their circumference and also at positions along their longitudinal extent with good controlability of the path of the split gap, without time-wasting and costly metal cutting operations being necessary, while at the same the avoidance of these operations brings with it no increase in the proportion of rejects.

Embodiments of the invention in the form of rolling bearing race rings, and their production, will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows, in perspective, the formation according to a method of the invention of a split gap in a race ring, Figure 2 also shows, in perspective, the formation according to a method of the invention of a split gap in a race ring and Figure 3 is a partial section on an enlarged scale taken on the line Ill in Figure 2.

Figure 1 shows a race ring 1 which is to be formed with a gap at a position on its circumference. This race ring is supported in a vee notch in a prismatic body 2 and is capable of being subjected to a compresive force by means of a punch 3.

The outer surface 4 of the race ring is acted on along the intended V-shaped path 5 of the split gap and within confined limits transversely thereto with an energy rich radiation and a split gap in the desired position is thus produced.

The race ring 1 is so positioned beneath the punch 3 that the outer surface 4 in the region thereof acted upon by the radiation is subjected to tensile stress by the compressive force exerted on the race ring 1 by the punch 3 for splitting it.

Since the material, which has been very greatly embrittled by the action of the energy-rich radiation, breaks down substantially sooner when it is under tensile stress than, for example when it is under compressive stress, the force required to produce a split gap is particularly small due to the abovedescribed arrangement of the race ring 1 relatively to the punch 3.

Figure 2 shows a race ring, indicated by the reference numeral 6, which is to be formed with a gap at a position along its length. This race ring 6 is supported inside its central bore of by means of two supporting members 7.

The outer surface 8 of the race ring 6 is acted on along the intended path 9, indicated by a chain dotted line, of the split gap and within confined limits transversely thereto, the outer surface 8 being formed along a part of this path 9 with a groove 10 of substantially rectangular cross-section, the base 11 of which groove is also subjected to the action of the energy-rich radiation.

The groove 10 is arranged to cooperate with a wedge-shaped punch 12 by means of which the force necessary for forming a split gap in the race ring 6 is applied.

As shown in Figure 3 the geometry of the punch is so related to that of the groove that, when the race ring 6 is acted on by the punch 12, the latter, by means of its wedge surfaces 13, exerts outwardly directed forces on the edges 14 of the groove, but does not make contact with the base 11 of the latter.

The result thereby attained is that the base 11 of the groove is subjected to tensile stress in the region 15 acted upon by the radiation.

The race rings shown in the figures of the drawings are acted upon by the energy-rich radiation only against one of their boundary surfaces. Obviously, however, both in the case of race rings and also in the case of any desired other kinds of components, a plurality of boundary surfaces may instead be subjected to the action of the radiation.

Claims (7)

1. IA A method of manufacturing a homogeneously hardened or depth hardened component part provided with a split gap, characterised in that, prior to the splitting operation, one of the surfaces (4,8) of the component part (1,6) is subjected, at least along a part of the intended path (5,9) of the split gap and within confined limits transversely thereto, to the action of an energy-rich radiation.
2. 2. A method according to claim 1, characterised in that the energy-rich radiation which acts on the component part is in the form of a laser beam.
3. 3. A method according to claim 1 or 2, characterised in that the surfaces (4) which are acted on by the radiation are subjected, by the force applied to the component partforforming a split gap therein, to tensile stress in the irradiated region thereof.
4. 4. A method according to claim 1 or 3, characterised in that the surface (8) which is acted on by the radiation is formed with a groove (10) at least along a part of the intended path (9) of the split gap and the base of this groove is acted on by the radiation.
5. 5. A method according to any of the preceding claims, wherein the component part is a race ring of a rolling bearing.
6. 6. A method of manufacturing a component part provided with a split gap substantially as described with reference to the drawings.
7. 7. A component part produced by a method according to any of the preceding claims.