阅读说明：本技术 用于在轮毂的内圈上形成前齿的改进的设备和方法 (Improved apparatus and method for forming front teeth on inner ring of hub ) 是由 法比奥·博格利亚西诺 亚历山德罗·费列罗 吉奥尔吉奥·弥赛亚 于 2021-06-21 设计创作，主要内容包括：设备(30)包括刚性的板(15),该刚性的板(15)设置有多个刀具(20),多个刀具(20)被构造为依次压靠轮毂(1)的内圈(3)的型锻环形挡环(10),该挡环形成有第一径向轮廓(9)；刀具(20)在轴向上滑动穿过板(15)并朝向板的抵接挡环(10)搁置的第一面(11)滑动；其中,板的第一面在刀具的区域中设置有凹形的环形座(15),该凹形的环形座(15)具有第二径向轮廓(16),该第二径向轮廓(16)被构造为至少部分地复制挡环的第一径向轮廓(9),环形座(15)被构造为在压靠挡环的步骤期间由刀具(20)穿过并且容纳形成挡环(10)的金属材料的任何径向流。(The apparatus (30) comprises a rigid plate (15), the rigid plate (15) being provided with a plurality of cutters (20), the plurality of cutters (20) being configured as a swaged annular check ring (10) which is pressed in turn against an inner ring (3) of the hub (1), the check ring being formed with a first radial profile (9); the tool (20) slides axially through the plate (15) and towards the first face (11) of the plate on which the stop ring (10) rests; wherein the first face of the plate is provided with a concave annular seat (15) in the region of the cutter, the concave annular seat (15) having a second radial profile (16), the second radial profile (16) being configured to at least partially replicate the first radial profile (9) of the baffle ring, the annular seat (15) being configured to be crossed by the cutter (20) and to accommodate any radial flow of the metallic material forming the baffle ring (10) during the step of pressing against the baffle ring.)

1. A device (30) for forming front teeth (5) on an inner ring (3) of a wheel hub (1) by plastic deformation, wherein the inner ring is provided at a first end (6) thereof with an annular baffle ring (10) having a first radial profile (9); the apparatus comprises a base (31) and a plate (22, 22B), the plate (22, 22B) having an axis of symmetry (B) and carrying a plurality of cutters (20) sliding parallel to the axis of symmetry, the plurality of cutters (20) being arranged in an annular manner, the plate (22, 22B) being mounted on the base (31) axially movable along the axis of symmetry (B), and the base (31) being configured to rigidly receive the hub (1), wherein the inner ring (3) is angularly locked and the baffle ring (10) faces a first face (11) of the plate directed towards the base; characterized in that said first face (11) is provided with a concave annular seat (15, 150) in the region of said tool (20), said concave annular seat (15, 150) having a second radial profile (16, 40), said second radial profile (16, 40) being configured to at least partially replicate the first radial profile (9) of the slinger; the annular seat (15, 150) is configured to be crossed by the cutter (20) as a result of the sliding of the cutter (20) in the plate (22, 22b) towards the base.

2. The apparatus according to claim 1, characterized in that the first face (11) is configured to rest substantially against the inner ring (3) of the hub during use.

3. The apparatus according to claim 1 or 2, characterized in that said second radial profile (16) of said annular seat (15) is configured to fully reproduce said first radial profile (9), the second radial profile (16) comprising a first radially inner portion (26), a second radially outer portion (27) and a third portion (28), the first radially inner portion (26) has a shape matching a corresponding first radially inner portion of the first radial profile (9), the second radially outer portion (27) has a shape matching a corresponding second radially outer portion of the first radial profile (9), -said third portion (28) is configured for connecting together said first and second radially inner portions and has a shape matching a corresponding third portion (43) of said first radial profile (9) delimiting the top of said first radial profile (9); the cutters (20) are slidably housed within respective radial slots (38), the radial slots (38) passing axially through the plate (22) and being formed in an annular manner along a third portion (28) of the second radial profile, so as to intercept the third portion (28) and interrupt the continuity of the annular seat (15) at least along the third portion (28).

4. The apparatus according to claim 1 or 2, characterized in that said second radial profile (40) of said annular seat (150) comprises a first radially inner portion (41) and a second radially outer portion (42), said first radially inner portion (41) having a shape matching a corresponding first radially inner portion of said first radial profile (9), said second radially outer portion (42) having a shape matching a corresponding second radially outer portion of said first radial profile (9); -said plate (22b) is provided, on said first face (11), with an annular compartment (380), said annular compartment (380) having the shape of a cylindrical crown and axially intercepting said annular seat (150), said annular seat (150) being interrupted in the circumferential direction between a first radially inner portion (41) and a second radially outer portion (42) of a second radial profile of said annular seat (150), so as to directly face, during use, a third portion (43) of said first radial profile arranged at the top thereof; the knives (20) are housed side by side, axially slidable through the plate (22b) up to the inside of the annular compartment (380).

5. The apparatus according to claim 4, characterized in that said cutter (20) is mounted on a disc (19), slidably passing through said disc (19), said disc (19) being fixed against a second face (39) of said plate (22b) opposite to said first face; the plate is divided into a first radially outer annular portion (44) and a second substantially cylindrical central portion (45), the second central portion (45) being fastened to the first radially outer portion by the disc (19); the first and second radially outer portions (44, 45) and the plate (22b) delimit the annular compartment (380) in the shape of a cylindrical crown between the first and second radially outer portions (44, 45).

6. The apparatus according to any one of the preceding claims, wherein the tools (20) have a profile that is complementary in the circumferential direction to the profile of the front tooth (5) to be obtained, so that each tool (10) can form, when pushed against the inner ring (3), the profile of the flanks of two adjacent teeth of the front tooth (5) to be obtained on the inner ring; the apparatus further comprises a ram (23) for selectively moving the cutters in sequence axially towards the base (31) and against a collar (10) of an inner ring of a hub configured to lock onto the base, after the plates (22, 22b) have been configured to abut against the inner ring.

7. The apparatus according to any one of the preceding claims, wherein the concave annular seat (15, 150) formed on the first face of the plate (22, 22b) is configured to engage, during use, with a baffle ring (10) of the inner ring (3) of the hub, so as to contain any radial plastic flow of the metallic material forming the baffle ring (10) during plastic deformation of the baffle ring (10) following axial movement of the cutter (20) with respect to the plate towards the base.

8. The apparatus according to claim 7, characterized in that said concave annular seat (15, 150) provided on the first face (11) of the plate (22, 22b) is configured to engage, during use, with a baffle ring (10) of an inner ring of the hub, said baffle ring (10) having a predetermined clearance, at least in an axial direction, with respect to the plate, to allow, during plastic deformation of the baffle ring following the axial movement of the cutter (20), a plastic flow of the metal material forming the baffle ring to form a tooth (5) on the inner ring, the height of said tooth (5) being greater than the depth of the cut of the cutter on the baffle ring.

9. A method for forming front teeth (5) on an inner ring of a hub (1) by plastic deformation, the method comprising the steps of:

-forming a swaged annular ring (10) having a first radial profile (9) on one end of the inner ring (3) of the hub;

-plastically deforming the slinger (10) to frontally realize front teeth (5) on the slinger (10) by pressing a plurality of knives (20) axially and in sequence on the slinger, said plurality of knives (20) being guided axially slidably through a rigid plate (22, 22b), said rigid plate (22, 22b) frontally abutting the slinger (10) before pressing said knives on the slinger; characterized in that it further comprises a step of accommodating any possible radial plastic flow of the metallic material forming the slinger, the accommodating step being carried out by providing a concave annular seat (15, 150) on a face (11) of the plate directed towards the slinger, the accommodating step being carried out simultaneously with the plastic deformation of the slinger following the axial movement of the tool (20) with respect to the plate, the concave annular seat (15, 150) having a second radial profile (16, 40) configured to at least partially replicate the first radial profile (9) of the slinger; the annular seat (15, 150) is configured to be crossed by the cutter (20) during the pressing thereof against the stop ring.

10. Method according to claim 9, characterized in that during the pressing of the cutter (20) against the baffle ring (10), the hub (1) is supported locked both axially and radially with respect to the axis of symmetry (a) of the hub (1) on a seat (31) configured to face the plate (22, 22B) and is also held with its inner ring (3) locked angularly so that it cannot rotate about the axis of symmetry (B) of the plate configured coaxially to the axis of symmetry of the hub.

Technical Field

The present invention relates to an improved apparatus and associated method for forming front teeth on an inner ring of a hub by plastic deformation.

In particular, the invention is applicable to a wheel hub, the inner ring of which comprises a stub shaft (stub axle) provided with a first raceway for a first row of rolling elements and an "insert" ring provided with a second raceway for a second row of rolling elements, wherein the insert ring is axially locked on the stub shaft by means of a swaged ring (swaged Collar) defined by the already plastically deformed end portion of the stub shaft.

Background

In a hub of the above type, the purpose of said front teeth is to couple the inner ring of the hub end-to-end with corresponding front teeth of the outer ring of a constant-velocity joint to ensure the transmission of torque from the constant-velocity joint to the inner ring of the hub, which carries the wheels of the vehicle by its flanged end. This type of coupling is described in US-A-4893960, which also teaches how to form front teeth on the inner ring of the hub. In particular, the forming of the swage ring is accompanied by the formation of the front teeth using the so-called "orbital forming" method, by means of a tool comprising a frustoconical element swaging the ring and a frontally toothed tubular element axially slidably mounted on the outside of the frustoconical element and pressing out the teeth on the ring still deformed. An element radially external to the toothed tubular element (which may form part of the same tool or form a second separate tool) controls the deformation of the ring radially towards the outside.

Forming methods such as that described in US-A-4893960, although satisfactory, require the use of relatively complex tools, in particular those that do not ensure the formation of teeth having highly uniform tooth profile characteristics, which is absolutely necessary in view of the increasingly high torques that must be transmitted.

The above problem has been solved by using a plurality of tools for the pressing of the front teeth, which are pressed in turn against the swaging collar, each tool moving independently of the other, so that the front teeth can be obtained by plastic deformation, wherein the profile of the teeth remains substantially uniform, while ensuring a greater dimensional accuracy of the teeth thus obtained.

However, during assembly of the hub and the constant velocity joint, incorrect fitting between one tooth and the other may occur, which means that the teeth of the two components do not engage together correctly. This is due to the fact that: according to design specifications, the tips of the teeth obtained by pendulum forming on the hub, rather than being perfectly rounded, tend to flatten out during the forming process. This prevents the corresponding teeth of the constant velocity joint from performing a correct engagement in one of the grooves between the teeth of the front teeth of the hub, which defines the bottom of said front teeth, during use.

Subsequently, the teeth of the hub/constant velocity joint unit, which have been assembled incorrectly, naturally engage in the correct position due to the weight of the vehicle receiving the hub/constant velocity joint unit or during the first transmission of torque from the constant velocity joint to the wheel, but this results in the central screw or nut used to lock the two components together immediately losing the fastening force applied during assembly and possibly creating a positive play (front play) between the two sets of engaging teeth of the hub and the constant velocity joint, even if torque transmission is still ensured.

This results in whistling noise along the shaft (whistling noise) since the teeth jump out of the correctly engaged position whenever a higher torque is transmitted, since the tightening force of the central screw is at least partially reduced.

In a vehicle affected by such a situation, in the case of a 2WD (two wheel drive) vehicle, the traction of the entire vehicle is prevented even if there is no traction force on one side due to the mechanical structure of the axle differential, so that the teeth gradually wear and the traction force is completely lost. In AWD vehicles, where four drive wheels are not always engaged, there is a partial loss of traction of the vehicle.

In both cases, if the driver does not detect a loss of power on the axle, a gradual degradation of the gears may occur because the non-trailing axle still produces a plausible ABS signal so that the control unit of the vehicle does not detect an abnormal condition in time.

Disclosure of Invention

It is therefore an object of the present invention to provide a device and an associated method for forming front teeth on the inner ring of a hub by plastic deformation, which are an alternative to the devices and methods existing in the prior art, and which in particular are able to ensure not only a greater dimensional accuracy of the teeth and a high uniformity in terms of both the dimensions and the geometry of the profile of said teeth, but in particular to avoid the appearance of tooth tips (tip) or tooth crests (crest) flattening (flattening) in normal teeth obtained by pendulum grinding forming.

Thus, based on the present invention, an improved apparatus and associated method are provided for forming front teeth on an inner ring of a hub by plastic deformation, as defined in the appended claims.

Drawings

Further characteristic features and advantages of the invention will become apparent from the following description of two non-limiting examples of embodiments of the invention, provided with reference to the accompanying drawings, in which:

figure 1 shows, in schematic form, a front and radial section of a device provided according to the invention and designed for forming front teeth on an inner ring of a hub by plastic deformation;

figure 2 shows, in an enlarged schematic form, a three-quarter perspective view from above of the main components of the apparatus according to figure 1;

fig. 3 shows, in an enlarged schematic form, a three-quarter perspective view from below of the same main components of the device according to fig. 1, which has been shown in fig. 2;

figure 4 shows, in schematic form, a front view taken along the plane indicated by the line IV-IV of the assembly shown in figure 2, alongside another main assembly of the apparatus according to figure 1;

for greater clarity, fig. 5 shows in schematic form a portion of a hub provided with front teeth that can be obtained by the device according to fig. 1;

figure 6 shows in schematic form a three-quarter perspective view from below of a possible variant of the assembly shown in figures 2 to 4; and

figure 7 shows, in schematic form, a radial cross-section elevation of the assembly according to figure 6.

Detailed Description

With reference to fig. 5, the reference numeral 1 denotes as a whole a hub (wheel hub), known per se and only partially shown for the sake of simpler illustration, comprising an outer ring 2 and an inner ring 3, the outer ring 2 being intended to be fastened in a known manner to a suspension upright (not shown) of a vehicle during use, the outer ring 2 and the inner ring 3 being arranged between them with two rows of rolling bodies 4, of which only one row of rolling bodies 4 is shown in fig. 5.

The inner race 3 may be operatively associated during use with a known constant-velocity joint (not shown for the sake of simpler illustration) by means of front teeth 5 formed on a first end 6 thereof, and the inner race 3 is provided with a flange (not shown for the sake of simpler illustration), for attaching the vehicle wheel on the opposite side of the end 6.

In the non-limiting example shown, the inner race 3 comprises a short shaft (stub axle)7 defining the end 6 and an "insert" ring 8 embedded in the end 6, the "insert" ring 8 being directed towards the constant velocity joint during use; the inner ring 3, the stub shaft 7 and the insert ring 8 are coaxial with each other, having a common symmetry axis a coinciding with the general symmetry axis of the entire hub 1.

The inner ring 3 is provided with a swaged collar 10, the swaged collar 10 being obtained by plastically deforming the tip 6 by pendulum forming and having a first predetermined radial profile 9 (schematically shown in dashed lines in fig. 4 and 7).

In the non-limiting example of embodiment shown, the ring 8 is locked axially to the stub shaft 7 by means of a swage ring 10 projecting axially with respect to the ring 8.

In any case, the baffle ring 10 is provided with front teeth 5, the front teeth 5 being formed on a front end face 12 of the baffle ring 10, the front end face 12 being arranged substantially perpendicular to the axis of symmetry a of the hub 1, in particular of the inner ring 3.

Referring now also to fig. 1 to 4, the front teeth 5 are obtained by means of a plastically deformable pendulum-forming apparatus 30 (fig. 1), which plastically deformable pendulum-forming apparatus 30 is similar to the apparatuses commonly used for (known) pendulum-forming the baffle ring 10 on the inner ring 3 of the hub 1.

The apparatus 30 comprises a base 31 and a substantially rigid plate 22 (fig. 2 to 4), the plate 22 having an axis of symmetry B and carrying a plurality of known knives (/ cutters) 20 slidably parallel to the axis of symmetry B, only one of the knives 20 being schematically shown in the perspective view of fig. 4 for the sake of simpler illustration.

The tool 20 is arranged in an annular manner and is mounted by the plate on a plate 22 movably (more specifically, axially slidably) parallel to the axis B.

The plate 22 is correspondingly mounted on a base 31, axially movable along the axis of symmetry B, and the base 31 is configured to rigidly receive the hub 1, with the inner ring 3 angularly locked and the baffle ring 10 facing the first face 11 of the plate 22 directed towards the base 31.

In particular, the base 31 supports a frame 32, the frame 32 being formed in the manner of a gantry (gantry) and comprising a support (/ tower) (pylon)33, preferably the support 33 being vertically configured, a crosspiece (cross) 34 sliding along the support 33 parallel to the axis B, the crosspiece 34 removably supporting the plate 22 with the knives 20, for example by means of screws 35.

The frame 32 also comprises a fixing crosspiece 36, the fixing crosspiece 36 being mounted transversely on top of the support 33 and being provided with a through hole 37, in which through hole 37 a tool formed by a known edge-rolling forming ram 23 can be lowered, the tool being delimited at the front by the tapered surface 24.

The cutter 20 (fig. 4) is guided substantially without play in a corresponding seat 38 of the plate 22, the cutter 20 comprising a slot formed through the plate 22 and being configured (i.e. formed and arranged) as a segment of a circular crown (fig. 2).

The cutter 20 is also provided with a corresponding head 21 on the opposite side of the face 11, the radial and circumferential dimensions of the head 21 being greater than those of the slot 38 to prevent the cutter 20 from "falling" out of the plate 22 through the slot 38.

During use, the head 23 is pressed with its conical surface 24 against the head 21 of the tool 20.

By rotating the head 23 about an axis which is arranged inclined with respect to the axis of symmetry B of the plate 22 and which coincides, during use, with the axis a of the hub 1 which is lockingly mounted on the base 31, and by moving this inclined axis of the head 23 in precession while rotating about the axes B and a, the knives 20 are selectively pressed in sequence, preferably one at a time, against the stop ring 10 previously formed by swaging using a device similar to the device 30.

The ring 3 is in fact directly rigidly supported by the base 31 and therefore cannot be moved or driven in rotation.

According to a main aspect of the invention, the first face 11 is provided with a concave annular seat 15 (fig. 4) in the region of the tool 20, the concave annular seat 15 having a second radial profile 16, the second radial profile 16 being configured to reproduce, completely or at least partially, the first radial profile 9 of the baffle ring 10, as schematically shown in fig. 4.

During the operation for forming the slinger 10, the profile 9 is specifically designed and the profile 9 is manufactured with high precision from the metal material constituting the inner ring 3 (in particular, the metal material constituting the inner ring 3 on the side of the end portion 6). This is therefore known, so that the profile 16 can be easily manufactured subsequently to "copy" the profile 9, i.e. to cooperate with the profile 9.

Thus, during the formation of the tooth 5 obtained by pressing the tool 20 against the previously formed ring 10, the annular ring 10 is completely housed inside the annular seat 15, with the profile 5 resting against the profile 9 or separated from the profile 9 with a minimum clearance ("minimum" is understood to be a parameter of the order of tenths of a mm). Preferably, the minimum clearance is present mainly in the axial direction.

For this purpose, the first face 11 is configured to rest (rest) substantially against the inner ring 3 of the hub 1 during use.

The annular seat 15 is also configured to be crossed by the cutter 20 as a result of the sliding movement of the cutter 20 inside the plate 22 and towards the base 31, thanks to the fact that: a seat or slot 38 extends from a top surface 39 of the plate 22, opposite and parallel to the face 11, towards the face 11 (the bottom surface in the example shown, in which the axes a and B are arranged substantially vertically) and emerges within the annular seat 15.

Preferably, the second face 39 is provided with an insertion surface 18 (shown in broken lines in fig. 4) for housing the flat disc 19, the flat disc 19 being further provided with a groove corresponding to the seat 38, and against which the head 21 rests on the opposite side of the insertion surface 18.

The knives 20 have a profile in the circumferential direction complementary to the profile of the front tooth 5 to be obtained, so that each knife 10, when pushed against the inner ring 3, is able to form on the inner ring 3 the profile of the flanks (flank) of two adjacent teeth of the front tooth 5 to be obtained.

The disc 19 (optional) is intended to support a set of tools 20 already arranged in the desired position for insertion in the seats 38. In this way, it is possible to replace easily and very quickly a tool 20 that may have worn, or a tool 20 having a working end or tip or edge 25 with a first circumferential profile, with a tool 20 having a working edge 25 with a second circumferential profile, different from the first, to press/form a tooth 5 with a different profile.

In accordance with the present invention, during the axial sliding of tool 20 in plate 22, working tip or edge 25 enters inside annular seat 15 to plastically deform previously swaged ring 10 and form teeth 5 on ring 10.

Such axial sliding movement is generated by the ram 23, which is lowered until the ram 23 comes into abutment with the head 21, to selectively move the cutter 20 axially in turn towards the base 31 and into abutment against the stop ring 10 of the inner ring 3 of the hub 1, which is configured locked on the base 31, after the plate 22 has been configured against the inner ring 3.

During this plastic deformation step, the metal material from which the slinger 10 is made "flows", forming the troughs and individual teeth of the front teeth 5 with displaced metal material.

However, during this step, unlike the prior art, the deformed metallic material is not free to move radially, but is accommodated (/ restrained) at least in the radial direction by the presence of the annular seat 15, as will be seen.

Fig. 2 to 4 show a first embodiment of the annular seat 15.

According to this embodiment (and also preferably), the radial profile 16 of the annular seat 15, which extends circumferentially in a uniform manner, is configured so as to completely "duplicate" (i.e. to completely follow) the radial profile 9 of the baffle ring 10, and the annular seat 15 is formed by machining the face 11, as is the groove 38.

Thus, the radial profile 16 (fig. 4) comprises a first radially inner portion 26, a second radially outer portion 27 and a third portion 28, the first radially inner portion 26 having a shape matching a corresponding first radially inner portion of the profile 9 of the baffle ring 10, the second radially outer portion 27 having a shape matching a corresponding second radially outer portion of the profile 9, the third portion 28 being configured to connect the portions 26 and 27 together and having a shape matching a corresponding third portion 43 of the profile 9 delimiting the top thereof.

As has been seen, the knives 20 are slidably housed in respective radial slots 38 axially passing through the plate 28, according to one aspect of the invention, the knives 20 are formed in an annular manner at least or preferably only along the third portion 28 of the profile 16, so as to intercept (intercept) this third portion 28 and interrupt (intercept) the continuity of the annular seat 15 at least in the region of the third portion 28.

In this way, the portions 26 and 27 can be used as elements to radially contain the material of the retainer ring 10 when the tool 20 is pressed against its retainer ring 10.

Furthermore, along the circumferential portion of the annular seat 15 not provided with the groove 38 (left-hand side of fig. 4), the top portion 28 of the profile also ensures axial containment (axial containment) of the material of the slinger 10 when the cutter 20 cuts into the slinger 10.

Thus, the plastically deformable material of the slinger 10 has been accommodated (/ restrained) in both the radial and axial directions by the predetermined profile 16 calculated from the design specifications during its plastic flow movement.

As a result, surprisingly, it is possible to obtain a tooth 5 in which the top of the tooth is perfectly rounded and which has a greater height for the same penetration (and therefore axial displacement) of the cutter 20 as a whole.

Referring now to figures 6 and 7, these show a plate 22b provided with a second embodiment of the annular seat 15, said annular seat 15 being indicated by reference numeral 150 for greater clarity.

For the sake of simplicity, details similar or identical to those already described are denoted by the same reference numerals.

The annular seat 150 differs from the annular seat 15 already described in that the annular seat 150 has a radial profile 40 extending circumferentially in a uniform manner, but the radial profile 40 is configured to "duplicate" the radial profile 9 only partially, precisely along the radially outer and inner peripheral portions of the radial profile 9.

The radial profile 40 in fact comprises (fig. 7) a first radially inner portion 41 and a second radially outer portion 42, the first radially inner portion 41 having a shape matching the corresponding first radially inner portion of the profile 9, and the second radially outer portion 42 having a shape matching the corresponding radially outer portion of the profile 9.

However, instead of being provided with a plurality of seats or grooves 38 arranged in an annular manner as in the plate 22, the plate 22b is provided with an annular compartment 380 on the side of its first face 11, the annular compartment 380 having the form of a cylindrical crown which intercepts (interrupts) the annular seat 20 in the axial direction, interrupting (interrupting) the annular seat in the circumferential direction between the first portion 41 and the second portion 42 of the radial profile 40 of the annular seat.

In this way, annular compartment 380 directly faces third top portion 43 of profile 9 of baffle ring 10 during use.

In this embodiment, according to a first solution, the knives 20 are housed side by side, axially slidable through the plate 22b, completely slidable within the annular compartment 380 without lateral guides, and the annular compartment 380 thus extends up to the insertion surface 18.

In a second solution, which is an alternative to the first solution described above, the knives 20 instead extend up to the inside of the annular compartment 380, whereas the annular compartment 380 extends only partially within the thickness of the plate 22b (the distance between the faces 11 and 39) from the side of the face 11, whereas on the side of the face 39 a slot 38 (not shown) will be provided for supporting and guiding the knives 20, said slot being entirely similar to those already described, but being shorter and appearing directly within the annular compartment 380.

In the first solution, in order to support and guide the knife 20, it is advantageously possible to use a disc 19 configured as already described, so that the knife 20 is slidably mounted on the disc 19 and passes through the disc 19, said disc being fixed against the second face 39 of the plate 22 b.

Furthermore, in this first solution, the plate 22b (fig. 7) is divided into a first radially outer portion 44 having an annular shape and a second central portion 45 having a substantially cylindrical shape, and the second central portion 45 is rigidly fastened to the first portion 44 by means of the disc 19, the disc 19 being fixed to both the first portion 44 and the second central portion 45 by means of screws (not shown for the sake of a simpler illustration) screwed into the blind holes 46, and the disc 19 resting on the radially outer edge of the insertion surface 18.

In this way, the first and second portions 44, 45 of the plate 22b form and delimit between them an annular compartment (annular component) 380 in the shape of a cylindrical crown.

Thus, the concave annular seat 150 formed in the first face 11 of the plate 22b is configured to engage, during use, the check ring 10 of the inner ring 3 of the hub 1 to accommodate (continain) any radial plastic flow of the metallic material forming said check ring 10 during plastic deformation of the check ring 10 following axial movement of the cutter 20 with respect to the plate 22b towards the base 31.

In both embodiments, the concave annular seat 15 or 150, respectively formed on the first face 11 of the plate 22 or 22b, is preferably configured to engage with the baffle ring 10 of the inner ring 3 of the hub 1 with a predetermined play (play) during use (at least in the axial direction with respect to the plate 22/22b, as already seen), and with a value that allows a plastic flow of the metallic material of the baffle ring 10 to be formed during the plastic deformation of the baffle ring 10 following the axial movement of the cutter 20, so as to form on the inner ring the teeth 5 whose height is greater than the depth of the cut (input) of the cutter on the baffle ring 10.

As is clear from the description provided so far, the present invention also relates to a method for forming front teeth 5 on the inner ring of hub 1 by plastic deformation, comprising the steps shown below.

During a first step, a swaged annular ring 10 having a first radial profile 9 of predetermined size and shape characteristics is formed in a known manner (for example by pendulum rolling) on one end 6 of the inner ring 3 of the hub 1.

During a second step, the stop ring 10 is plastically deformed to form the front teeth 5 on the stop ring 10, a plurality of tools 20 are axially and sequentially pressed in on the stop ring 10, said plurality of tools 20 being guided axially slidable through a rigid plate 22 (or 22b), the rigid plate 22 (or 22b) being frontally abutted against said stop ring 10 before pressing (impressing) the tools 20 on the stop ring 10.

During the third step, according to a main aspect of the invention, containment of any possible radial plastic flow of the metallic material forming the baffle ring 10 is performed.

This third step of accommodating the metallic material of the baffle ring 10 is performed simultaneously with the step of plastic deformation of the baffle ring 10 after the axial movement of the tool 20 with respect to the plate 22/22b, providing on the face 11 of the plate 22/22b directed toward the baffle ring 10 a concave annular seat 15 (or 150), the concave annular seat 15 (or 150) having a second radial profile 16 (or 40), the second radial profile 16 (or 40) being configured to at least partially replicate the first radial profile 9 of the baffle ring 10.

In both embodiments, the annular seat 15/150 is configured to be crossed by the knife 20 during the pressing of said knife 20 against the baffle ring 10.

Furthermore, during the pressing of the cutter 20 against the baffle ring 10, the hub 1 is supported locked, axially and radially with respect to its axis of symmetry a, on the base 31 arranged facing the plate 22/22B and also keeps its inner ring 3 angularly locked so as not to be able to rotate about the axis of symmetry B of the plate 22/22B arranged coaxially to the axis of symmetry a of the hub 1.

Therefore, the method for forming the teeth 5 by plastic deformation according to the invention first comprises the step of forming the check ring 10 by plastic deformation of the end portion 6 of the inner ring 3 but imparting the first predetermined radial profile 9 to the check ring 10.

In combination with this step, in the method according to the invention, only after the actual step of forming the swaged retaining ring 10, in time sequence after the end of said step for forming the retaining ring 10, the front teeth 5 are pressed against the retaining ring 10, directly against the finished swaged retaining ring 10, and the knives 20 are actuated by the ram 23 to apply one or more knives 20 axially in turn to the retaining ring 10, but at the same time at least the radial accommodation of the deformation of the retaining ring 10 is performed, due to the presence of the annular seat 15/150 precisely in the region of the retaining ring 10 where the cutting of the knives 20 takes place.

When the cutter 20 is pressed against the stop ring 10, the head 21 abuts against the top surface 39 of the plate 22, in which case the top surface 39 must be flat, or when the flat disc 19 is present, the head 21 abuts against the flat disc 19, the flat disc 19 acting as a precision end-of-travel stop for the cutter 20.

Thus, according to the method of the invention, the hub 3 is realized in a known manner as an already finished assembly, less the teeth 5, but with the stop ring 10 already formed.

Thereafter, the semi-finished assembly is rigidly mounted on the base 31, obtaining the front teeth 5 in the described manner, thus obtaining the finished hub 1.

The containment effect (containment effect) caused by the presence of the annular seat 15 with continuous radial profile or of the annular seat 150 with radial profile partially interrupted by the annular compartment 380 prevents the metallic material of the slinger 10 from flowing during the track forming step in undesired directions other than those required to form the teeth of the front teeth 5, so that it is possible to obtain teeth that are higher than those that can be obtained with known methods and using known apparatuses in the prior art.

The containment efficiency can be improved by setting an optimum value for the parameters of the track-forming shape of the slinger 10, which can be achieved independently of the teeth 5, as in the form of the inner ring 3 deformed/shaped after the end of the track-forming operation of the slinger 10, in particular the angle formed between the direction perpendicular to the axis a and the portion of the profile 43 immediately adjacent to the radially outer portion of the profile 9, which can be small, so as to obtain a steeper profile of the inner track-forming surface of the slinger 10.

Due to the rounded profile of the working edge 25 of the tool 20, the additional material of the tooth portion of the tooth 5 can be rounded, resulting in a rounded tip which is required to completely avoid the drawbacks of the prior art described in the background section.

Thus, all the objects of the present invention are achieved.