DE1236305B - Method and pressing tool for producing end surfaces on needle bearing cages - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

B21k

German class: 49i-16

Number: 1236 305

File number: R 338271 b / 49 i

Filing date: November 6, 1962

Opened on: March 9, 1967

The invention relates to a method and a pressing tool for producing metal cages for Needle roller bearings to the effect that the end sections of the cage webs guide the bearing roller bodies in parallel Achieve each other and the rolling elements are held in the radial direction in the cage.

In contrast to conventional roller bearings, in which the bearing rolling elements due to their limited Length-to-diameter ratio are essentially "self-controlling", needle roller bearings need precision machined ones Cages which are able to hold the rolling elements in their associated axial planes to lead precisely, d. H. in planes that contain the main axis of the bearing. An imperfect one Parallel positioning of the rolling elements in a needle bearing initially leads to a loss of the transmitted Force (reduced mechanical effectiveness) and further to breakage of the rolling elements. The invention relates to therefore a method for shaping the protruding into the punched-out rolling body recesses zo the end faces on the slightly inclined circumferential projections of the webs of needle bearing cages Presses in which the end sections of the cage bars are used to guide the rolling elements in parallel and a center piece widened in the circumferential direction on each web and on both sides thereof to the end sections of the recesses to projections extending in the circumferential direction with protruding End surfaces are provided for the rolling element holder, the middle piece of the web and the end surfaces of the projections in the radial direction with respect to the pitch circle of the rolling elements in opposite directions Sides of the circle are offset.

In such cages, each rolling body is thus in the circumferential direction through the opposite End sections of that pair of webs stored and guided, which rests on the roller body, for this purpose, these opposite end sections of a web of the web pair with the corresponding end sections of the other web a pair of plane-parallel support surfaces for form the roller body, which lie on a common chord plane, the two of which form the roller body between enclosing chordal planes parallel and symmetrical to one another with respect to are the geometric axis of the cage and have a distance between them which is equal the diameter of the rolling element (with the exception of the required fit tolerance). These Cage design is known.

Since the mentioned projections on said opposite end portions of the web ge method and press tool for manufacturing
of end faces on needle bearing cages

Applicant:

RIV Officine di Villar Perosa Societä per Azioni, Turin (Italy)

Representative:

Dr.-Ing. H. Fincke, Dipl.-Ing. H. Bohr
and Dipl.-Ing. S. Staeger, patent attorneys,
Munich 5, Miillerstr. 31

Named as inventor:

Giacomo Einaudi, Turin (Italy)

Claimed priority:

Italy of November 7, 1961 (20 200)

are put and there continue to be the protruding end surfaces of the projections in a conventional manner are formed by rolling or pressing the projections, said support surfaces are necessarily influenced by rolling or pressing, and they are uncontrollable in the finished cage Way deformed. The subsequent insertion of the rolling elements by snapping them into their associated gaps between the webs is difficult or impossible, and the rolling body are caused to tilt when the bearing is in use.

In contrast, the invention aims at a new and particularly expedient approach to training of the circumferential projections mentioned or their protruding end faces without any adverse effect the longitudinal support surfaces on the webs.

So far, the protruding end surfaces or circumferential projections by exerting a radial Deformation pressure formed on the relevant projection. This radial deformation pressure can be produced by pressing or rolling. Both in one case (pressing) and in the other Case (rollers), the end faces mentioned have a belly, the exact shape and position of which in the Practice are extremely difficult to check, so that on the one hand the end faces often in an undesirable manner are deformed and on the other hand the rolling elements

709 518/1 + 7

3 4

Difficult to insert into the corresponding windows F i g. 3 shows a diagrammatic partial view of a

permit. However, each roller body must have a relative projection on a cage bar together with a

easily snap into its window without a permanent pair of squeezing tools;

to cause severe bending of the two webs. FIG. 4 shows a view similar to that in FIG. 3

Also, the fact must be taken into account that 5 shown with concave pinch surfaces;

the needle bearings in the vast majority of cases are very small F i g. 5 shows a perspective partial view of a

Have dimensions with the radial thickness of the one-piece tool for simultaneous crimping

The cage rarely exceeds 2 to 2.5 mm. This explains the protrusions on opposite end sections

those with an effective test of a plastic th of a web;

Deformation process associated difficulties. io F i g. 6 is a partial view of a cross-section

It is well known that in order to achieve a long line VI-VI of FIG. 5, which is a practical

greatest possible precision punching for use, possibility to achieve concave squishy surfaces

manure must come, which, however, shows in the case of needle on the one-piece tool;

caging is practically impossible. Now that the F i g. 7 and 8 show partial views of cross-sectional

Forming pressure to form said protrusions through a protrusion and a tool in two

the end faces a substantial volume of metal at the various stages of the squeezing process;

relevant projections must displace, Fig. 9 and 10 show partial views of transverse

the emergence of the above-mentioned bellies not intersected along the lines IX-IX and X-X of the

avoid. In practice one tried a formation Fig. 7 or 8;

to counteract these bellies or their 20 Fig. 11 is a partial view of an axial transverse

Reduce training by making the pre-cut which is a one-piece tool in

stepping end surfaces only after the onset of the working position on a web of the in the F i g. 1 and 2

Rolling bodies into their respective windows. shows blank shown;

In this way, each rolling element acts as an "anvil", FIG. 12 shows a view of a cross-section.

on which too strong a metal flow during the line XII-XII of FIG. 7;

dung of the end faces comes to a standstill. On the one hand, Fig. 13 shows the partial view of a finished

But you run the risk of the rolling body in a cage, which has a rolling body between a

to "strangle" his window; on the other hand, pair of webs are used;

Fig. 14 shows a cross-sectional view of the devices in a more complicated manner, since it is from the tech- nology of the line XIV-XIV of Fig. 13.
In order to carry out the method of the invention, it is better to first completely finish the cage. The method of the invention is now based on three sections of each web. The nature of the basic prerequisites from: 35 Production of such a blank is not essential-

a) the deformation draft should be exerted in such a way that the tendon support surfaces for be that he only a small Radialkom- the rolling body in a precise manner to the opposing component having set end portions of the webs are limited.

b) the effective component must parallel the experimental as the best method to Herzur Extend cage axis, and 40 position of such a blank is developed

c) the zone on which the deformation pressure from turning the inner and outer surface of a is practiced, must be as small as possible (point metal sleeve to a desired profile enclosing or linear contact), so that in this borrowed a continuous pre-zone in the circumferential direction the highest possible specific deformation on each end section of the sleeve and pressure is achieved, even if the die 45 by means of the subsequent punching of the latter pressure is only relatively low. a punch press tool to circumferentially

In order to achieve the desired number of breakthroughs with very precise dimensions under these conditions

To achieve the th purpose, the implementation of the solution for the rolling bodies is carried out,

The aforesaid method such that the end surfaces in this way comprise that in FIGS

by simultaneous end crowns 21 opposite one another, shown on both sides of the same blank 20

Protrusion exerted, predominantly axially parallel and 22, associated therewith, in the axial direction

Pressure to be squeezed out. lying webs 23, which breakthroughs between them

Advantageous embodiments of the pressing mechanism 24 for the rolling elements 25 limit. In the quoted

The inner surface of the blank 20 is a characteristic example of the implementation of this method

are characterized by the fact that the pressing surfaces 55 are cylindrical with a constant diameter, while

on separately moving pressing tools arranged the outer surface on a lathe by means of

are or that the pressing surfaces are made as a roof-shaped form of a single, profiled cutting tool 26

Savings are arranged on a pressing tool is made. In this way the outer upper

wherein according to a special feature of the invention surface of the workpiece at the same time an accurate

said pressing surfaces are concave. 60 shaped profile, which has an axial center piece 27

The invention is shown below with reference to, which is located on a diameter

Embodiments and schematic drawing which is smaller than the main diameter of the

explanations. Blank, or which, better said, in radial

F i g. 1 shows a cross section through a cage direction in relation to the pitch circle 28 (see FIG. blank and a corresponding profile of a machining tool; called circle is reset. The blank

F i g. 2 shows a partially diagrammatic view profile also includes a circumferentially arranged

of the blank from FIG. 1; directed protrusion 30 on each end portion, 29

5 6

each web 23, the summit line or summit stepping being squeezed. A radially outward surface of the protrusion 30 with substantially directed flow of metal is aligned with the cylindrical surface. The transversely called radial component of the pressure in the cutout form of the projections 30 shown is slightly prevented, so that the metal in trapezoidal shape due to the manufacturing conditions 5 mainly in the circumferential direction in opposite directions (successful penetration and easy retraction along the gap between the Cutting tool 26). Therefore, the flanks of the tools flow so as to form protruding end 30a of each protrusion 30 (Fig. 12) around a winch on the protrusion. Since, as can easily be ascertained by those skilled in the art by kel β against a perpendicular to the cage axis, a plane 31 is inclined, the angle β expediently not exceeding 10 protrusion of a projection end of not more than 10 °. The cross-sectional shape of the front 0.2 mm into the opening is sufficient, if desired, the jump can also be rectangular to hold a roller body of 3 mm diameter in place - or it can follow a right-angled foot part, the plastic flow of the metal is relatively of have a trapezoidal top. In comparison to the volume of the projection, the pez-shaped shape also has a beneficial effect on the fact that the flow of the metal, originating in a certain zone of the projection length on the upper part of the center, bears the deforming pressure exerted by the projection Little to the formation of the protruding end at the base of the protrusion a lower, non-flat; therefore, a pre-deforming pressure is generated, according to the preferred embodiment of the invention, the squeezing pressure ratio of the respective areas. 20 mainly on the end zones of the projection

The punching process carried out in the radial direction is practiced. For this purpose, the in F i g. 4 shows openings 24 which alternately have tools 136 and 137 facing each other and facing allelic longitudinal wall surfaces and parallel protrusion 30 have a concave surface 136a end wall surfaces. The latter are in the or 137a. In this embodiment, the drawing is designated by 32, while each of the 25 four corners 30 'of the projection first touches a stepped surface from the longitudinally directed wall surfaces and represents plastically into horn-like fronts, soft a pair of plane-parallel end sections deforms jumps which extend in the circumferential direction 33 and a central part 34 comprises which extend over the in opposite directions, as it will be explained in the following plane of the end portions 33 in the direction of the,
opposite, longitudinal wall surface towards 30 Since the tools 36, 37 and 136, 137 protrudes. The clear width of the openings 24 suddenly press between them, such work their end sections is essentially the same as the two jaws of a pliers-like diameter of the rolling element 25, as previously fixed device. Such a presented while the opposite direction would, however, be relatively extensive and emp-surfaces 34 of the middle pieces 27 in each diameter 35 thin. It has now been shown that the press fractures are separated from one another by an opening, surfaces do not necessarily have to be movable relative to one another, which is smaller than the diameter of the roller must be borrowed. According to the most beneficial, body. Therefore, the surfaces of the end in FIG. 5 shown embodiment of the invention, sections 33 of the aforementioned tendon support surfaces, a type of embossing tool 40 is used, which has _{an elongated, flat surface 41 for guiding the rolling elements on a precise 40} , in which plane extending through the axis of the cage, transverse grooves 42 and 43 are formed at a mutual distance and form the widened middle pieces of the webs, which is the same as that of the two pre-radial inner brackets for the rolling elements. Self-jumps 30 on a web of the cage to be manufactured are understandably aligned as a result of the punching process. Each of the above-mentioned grooves has a V-shaped opposite end surfaces of each projection 30 4.5 cross-sectional shape and is easily made with their corresponding chordal surfaces 33, so that the ends of the projections 30 are not made into the through-hole by means of a rotating grinding or milling tool in Fig. 6 schematically with 44 bebrüche24 protrude. is drawn. Its cutting surface, its shape

According to the in F i g. 3, is double-conical, is directed perpendicularly against the surface in which a web 23 with one of its projections 30 50 41. Tools of this type are often indicated, the upper zone of the projection is used to produce V-shaped grooves when their between a pair of pressing tools 36,37, which cutting surface parallel to the surface to be machined, is directed against one another for pressing in the axial direction . The diameter of the grinding or arranging are. The pressing surfaces 36 a, 37 a of the work milling tool is smaller than the outer diameter are flat and form a kind of "roof" above the cage, so that the curvature of the bottom 45 is half of the projection, as they are inclined towards each other Grooves 42, 43 are greater than the curvature of that it is initially only the upper edges 30 a, ridge 46 of the projection 30 (see Fig. 9). Touch 30 b of projection 30. In this way, corresponding to the double-axial compression of the tools against the conical shape of the grinding or milling tool, an extremely high pressure is obtained on the upper zone 60, flanks 47 and 48 of each groove, which is exerted against that of the projection Pressure a projection are concave (Fig. 5).
bordered against the base of the projection. During the working process, the cage blank 20

having radial component. If such compo- (Fig. 11) is attached to a suitable mandrel 50, nente distributed over the cross-sectional area of the base with a web 23 through the mandrel in a radial it is insignificant and incapable of generating 65 direction is firmly supported and the tool 40 in a permanent deformation, while brought up on the other radial direction, so that it is with its Ren side, the upper zone of the projection through the grooves 42 and 43 on the two projections 30 high specific pressures exerted thereon strikes the web 23. The deforming axial pressure

Claims (4)

is first exerted on the four corners 30 'of the projection 30 through the groove flanks 47 and 48 (FIG. 7), as in FIG. 4 shown. As soon as the tool hits, the protrusion 30 wedges into the groove with the opposite end zones of the protrusion beginning to plastically deform and the protrusion metal plastically flowing circumferentially in opposite directions (Figs. 8 and 10). A backflow of the metal is prevented on the one hand by the limited radial component of the occurring pressure and on the other hand by the contact of the projection-tool, which progresses progressively towards the central zone of the projection length. As a result, the projection is squeezed in the axial direction and protruding end surfaces are formed on the projection, which take the shape of horn-like projections 51. Excellent results are achieved with half opening angles α of the wedges of the grooves 42, 43 (FIG. 12), which range between 10 and 35 °. Larger angles up to 40 to 45 ° can also be used, provided that the cooperating tool and projection surfaces are sufficiently lubricated to reduce friction. In addition, the angles α and β should advantageously be approximated in order to obtain a positive differential angle γ in the range of 4 to 5 °, so that a high specific pressure is kept as far away as possible from the base of the projection and thus also from the tendon support surfaces 33 is. 13 and 14 show a general view of the projections 30 on a finished cage with a rolling element 25 snap-fitted between a pair of the webs 23. It can be seen that the horn-like projections 51, which extend from the projections 30 in the circumferential direction in opposite directions, effectively prevent the rolling element 25 from escaping to the outside, the tendon support surfaces 33 remaining undamaged. Compared to the securing projections produced by known methods, the horn-like ends of the present projections have a specific ability in that they are easily rounded by a small amount when an evasive resistance occurs when inserting a roller body by snapping between them, so that an occasional permanent deformation the ridges when assembling the bearing is avoided. Patent claims: 1. Method for shaping the protruding into the punched-out rolling body recesses End faces on the slightly inclined circumferential projections of the webs of needle bearing cages by pressing, in which the end sections of the cage bars for parallel guidance of the rolling elements serve and a center piece widened in the circumferential direction on each web and on both sides of it, to the end sections of the recesses, with projections extending in the circumferential direction protruding end surfaces are provided for the rolling element holder, the middle piece of the web and the end faces of the projections in the radial direction with respect to the pitch circle of the Rolling bodies are offset on opposite sides of the circle, characterized in that that the end faces (30) by simultaneous, on both inclined sides of the same Protrusion exerted, not covering the entire surface, predominantly axially parallel pressure be squeezed out. 2. Press tool for performing the method according to spoke 1, characterized in that that the pressing surfaces (36 a, 37 a) are arranged on separately moving pressing tools. 3. Press tool for performing the method according to claim 1, characterized in that that the pressing surfaces (47, 48) as a roof-shaped recess (42) on a pressing tool (40) are arranged. 4. Press tool according spoke 2 or 3, characterized in that the pressing surfaces (136 a, 137a or 47, 48) are concave. Considered publications:
German Patent No. 1066 530;
German interpretative document No. 1001 550. For this purpose 2 sheets of drawings 709 518/147 2.67 ® Bundesdruckerei Berlin