JP4775017B2 - Method for manufacturing cylindrical member with protrusion - Google Patents

Description

The cylindrical member provided with the projecting portion as an object of the present invention is generally cylindrical (generally cylindrical) like an outer ring constituting a wheel support hub unit, and has a circumferential surface on the outer peripheral surface. It is a metal member provided with protruding piece-like protrusions provided intermittently in the direction . The present invention is intended to realize a manufacturing method that can accurately process a cylindrical member having such a protrusion at low cost.

  A wheel 1 constituting a wheel of an automobile and a rotor 2 constituting a disc brake as a braking device and a braking device rotate to a knuckle 3 constituting a suspension device, for example, by a structure as shown in FIG. Supports freely. That is, the outer ring 6 constituting the wheel support hub unit 5 is fixed to the circular support hole 4 formed in the knuckle 3 by a plurality of bolts 7. On the other hand, the wheel 1 and the rotor 2 are coupled and fixed to a hub 8 constituting the wheel support hub unit 5 by a plurality of studs 9 and nuts 10. Further, double-row outer ring raceways 11a and 11b are formed on the inner peripheral surface of the outer ring 6, and a coupling flange 12 is formed on the outer peripheral surface. Such an outer ring 6 is fixed to the knuckle 3 by connecting the connecting flange 12 to the knuckle 3 with the bolts 7.

  The hub 8 includes a hub body 13 and an inner ring 14. Among these, a mounting flange 15 is formed on a part of the outer peripheral surface of the hub body 13 and protruding from the outer end opening of the outer ring 6. Note that “outside” with respect to the axial direction refers to the left side of FIGS. On the other hand, the right side in FIGS. 4 and 5, which is the center side in the width direction of the vehicle in the assembled state in the automobile, is referred to as “inside” in the axial direction. The wheel 1 and the rotor 2 are coupled and fixed to the outer surface of the mounting flange 15 by the studs 9 and nuts 10.

  Further, an inner ring raceway 16a is formed in the middle portion of the outer peripheral surface of the hub body 13 so as to face the outer ring raceway 11a on the outer side of the double row outer ring raceways 11a, 11b. Further, the inner ring 14 is externally fitted to a small diameter step portion 17 formed at the inner end portion. An inner ring raceway 16b is formed on the outer peripheral surface of the inner ring 14 so as to face the inner outer ring raceway 11b of the double row outer ring raceways 11a and 11b. Such an inner ring 14 is fixed to the hub body 13 by a caulking portion 18 formed by plastic deformation of the inner end portion of the hub body 13 radially outward. A plurality of rolling elements 19, 19 are provided between the outer ring raceways 11a, 11b and the inner ring raceways 16a, 16b, respectively, so as to be able to roll. In the illustrated example, balls are used as the rolling elements 19, 19. However, in the case of a heavy vehicle hub unit, tapered rollers may be used. Further, both end openings of the cylindrical space in which the rolling elements 19 and 19 are installed are sealed with seal rings 20a and 20b, respectively.

  Furthermore, since the illustrated example is a wheel support hub unit 5 for driving wheels (front wheels of FF vehicles, rear wheels of FR and RR vehicles, all wheels of 4WD vehicles), A spline hole 21 is formed. A spline shaft 23 fixed to the outer end surface of the constant velocity joint outer ring 22 is inserted into the spline hole 21. At the same time, a nut 24 is screwed to the tip of the spline shaft 23 and further tightened, whereby the hub body 13 is sandwiched between the nut 24 and the constant velocity joint outer ring 22.

  Next, FIG. 5 shows a second example of a conventionally known wheel support hub unit for a driven wheel (rear wheel of FF vehicle, front wheel of FR vehicle and RR vehicle). Since the wheel support hub unit 5a of the second example is for a driven wheel, a spline hole is not provided at the center of the hub body 13a constituting the hub 8a. In the illustrated example, the inner end surface of the inner ring 14 is suppressed by a caulking portion 18 provided at the inner end portion of the hub main body 13a. However, the inner end surface of the inner ring 14 is the inner end portion of the hub main body 13a. It can also be suppressed by a nut screwed into the nut. In this case, a male screw portion for screwing the nut is provided at the inner end portion of the hub body 13a. The structure and operation of the other parts are the same as in the case of the wheel support hub unit 5 of the first example described above.

  By the way, in the case of each wheel supporting hub unit 5, 5a as described above, in any structure, the coupling flange 12 is provided at the intermediate portion of the outer peripheral surface of the outer ring 6, and the double-row outer ring raceways 11a, 11b are provided on the inner peripheral surface. Are formed respectively. As a method for processing such each part, cutting processing or the like can be considered in addition to plastic processing such as hot forging or cold forging. However, in order to improve the working efficiency, secure the yield of the material, and reduce the cost, it is preferable to carry out plastic working. Moreover, since hot forging can be processed in a soft state among plastic working, the molding load can be kept small, but considering the difference in thermal expansion, etc., the fitting part between the receiving die and the stamping die It is difficult to ensure the shape accuracy and dimensional accuracy of the processed product. In the case of hot forging, a decarburized layer is formed on the surface. Therefore, in the case where the surface needs to be hardened by heat treatment, the cutting process for removing the decarburized layer is performed after hot forging. I need it. Since the machining allowance due to this cutting process increases to some extent, this cutting process not only decreases the processing efficiency but also deteriorates the yield of the material, which increases the processing cost of the outer ring 6.

  Considering these things, it is considered that the outer ring 6 having the coupling flange 12 on the outer peripheral surface is manufactured by side extrusion, which is a kind of cold forging (Japanese Patent Application No. 2004-298585). ). FIG. 6 shows a situation in which the outer ring 6 is made by this side extrusion process. The present invention relates to the improvement of the side extrusion process of the prior invention, which is performed by the manufacturing apparatus as shown in FIG. 6, and the present invention and the prior invention have many common parts. First, the situation in which the outer ring 6 is manufactured using the side extrusion processing will be described in detail with reference to FIG. In FIG. 6, the right half indicates the state immediately before the start of processing, and the left half indicates the state immediately after the end of processing. First, the manufacturing apparatus will be described.

  A lower holding cylinder 26 is fixed to the upper surface of the lower plate 25 that is placed and fixed on the upper surface of a table (not shown) of the press machine. Further, a holding plate 27 is fixed inside the lower end portion of the lower holding cylinder 26, and a base end portion (lower end portion) of a cylindrical mandrel 29 is supported and fixed inside the center hole 28 of the holding plate 27, A cylindrical lower punch 30 is fitted around the lower half of the mandrel 29 on the upper surface of the holding plate 27. The lower punch 30 also has a function as a counter punch for extracting the processed intermediate material (second intermediate material) from the periphery of the mandrel 29. The lower punch 30 has an outer peripheral surface of the mandrel 29 and the lower side. A predetermined amount is provided between the inner peripheral surface of the thick cylindrical lower support block 31 held inside the holding cylinder 26 so as to be movable up and down. When the intermediate material is taken out, a pressure fluid such as pressure oil is introduced into the lower side of the lower punch 30 to raise the lower punch 30 by a predetermined amount and push up the intermediate material.

  A thick cylindrical lower mold 32 is fitted and fixed inside the upper portion of the lower holding cylinder 26. The upper part of the lower punch 30 is inserted into the center hole 33 of the lower mold 32 in a dense and axially displaceable state (up and down). Further, on the upper surface of the lower die 32, in the peripheral portion of the center hole 33, one half of the coupling flange 12 (see FIGS. 4 to 5) to be formed on the outer peripheral surface of the outer ring 6 (the state where the outer ring 6 is formed) The lower concave portion 34 corresponding to the shape of the outer half portion in the axial direction) is formed. On the other hand, on the upper outer peripheral surface of the mandrel 29, the outer ring of one of the pair of outer ring raceways 11a and 11b (see FIGS. 4 to 5) on the inner peripheral surface of the outer ring 6 (in the illustrated example, the outer side in the axial direction). A surface pressing portion 35 for forming the track 11a is provided.

  On the other hand, an upper plate 36 is provided above the lower plate 25 in parallel with the lower plate 25. The upper plate 36 is attached and fixed to the lower surface of a ram (not shown) of the press machine, and an upper die 37 is supported on the lower surface of the upper plate 36 so as to be able to move up and down slightly. That is, the upper die 37 is held inside the upper holding cylinder 38 fixed to the lower surface of the upper plate 36 so as to be able to move up and down by a predetermined amount. Then, an elastic member 39 such as a compression coil spring or an elastomer such as rubber is sandwiched between the upper surface of the upper die 37 and the lower surface of the upper plate 36 to give the upper die 37 elasticity downward. is doing. In addition, in order to give downward elasticity to the upper die 37, gas pressure or hydraulic pressure may be used in addition to the elastic member 39.

  The upper die 37 is formed with a center hole 41 into which the upper half of the intermediate material 40 (the inner half in the axial direction in the state of the outer ring 6) can be closely fitted. Further, in the lower surface of the upper die 37, the portion around the center hole 41 and the portion that aligns with the lower concave portion 34 is provided in the other half of the coupling flange 12 (in the state of the outer ring 6). An upper concave portion 42 corresponding to the shape of the inner half portion in the axial direction is formed. Further, an upper punch 43 is fixed inside the upper die 37. In the illustrated example, the upper punch 43 includes a cylindrical outer diameter side punch 44 and an inner diameter side punch 45. The intermediate material 40 is pressed downward by the front end surface (lower end surface) of the upper punch 43. The tip surface of the upper punch 43 has a stepped shape by shifting the positions of the tip surfaces of the outer and inner diameter side punches 44 and 45, and the intermediate material 40 is formed by the tip surface of the upper punch 43. At the same time as pressing downward, the upper end portion of the intermediate material 40 is plastically processed into a stepped shape.

  Next, the process of processing the intermediate material 40 into the second intermediate material 46 closer to the shape of the outer ring 6 by the manufacturing apparatus having the above-described configuration will be described. First, the intermediate material 40 is mounted between the lower mold 32 and the upper mold 37 as shown in the right half of FIG. The intermediate material 40 is formed by previously forming a stepped portion 47 in the intermediate portion of the outer peripheral surface by a warm forging process or a cold forging process, and a lower half portion (an outer half in the axial direction in the state where the outer ring 6 is formed). The outer diameter of the upper part is smaller than the outer diameter of the upper half (the inner half in the axial direction when the outer ring 6 is formed). The inner diameter is the same over the entire length. Such an intermediate material 40 is mounted between the upper half inner peripheral surface of the lower mold 32 and the upper outer peripheral surface of the mandrel 29. This mounting operation is performed with the upper die 37 and the upper punch 43 raised together with the ram of the press machine.

  Next, the ram that has been raised is lowered. First, as shown in the right half of FIG. 6, a portion near the upper surface outer diameter of the lower die 32 and a portion near the lower surface outer diameter of the upper die 37. Match. Next, the ram is further lowered, and the intermediate material 40 is strongly pressed toward the lower punch 30 by the upper punch 43. At this time, the elastic member 39 is elastically compressed. In this state, only the upper punch 43 is lowered while the portion near the upper surface outer diameter of the lower die 32 and the portion near the lower surface outer diameter of the upper die 37 are closely abutted. As a result, the lower half portion of the intermediate material 40 is plastically deformed, and the inner peripheral surface of the lower half portion of the lower mold 32 and the outer peripheral surface of the mandrel 29 are more than the surface pressing portion 35. It is pushed into the cylindrical space 48 between the lower part. Then, the lower half of the intermediate material 40 is plastic processed into a shape following the cylindrical space 48. In this state, one (axially outer) outer ring raceway 11a is formed.

  The lowering of the upper punch 43 continues until the lower half of the intermediate material 40 is completely pushed into the cylindrical space 48. As a result, a part of the intermediate material 40 flows (flows) into the radial space 49 constituted by the lower recess 34 and the upper recess 42, and the coupling flange 12 is formed. In this state, the intermediate material 40 is processed into the second intermediate material 46 that is closer to the shape of the outer ring 6. Thereafter, the ram is raised again, and the second intermediate material 46 formed with the coupling flange 12 is taken out. This removal operation is performed by raising the lower punch 30. Then, necessary post-processing (necessary) such as forming the other (axially inner) outer ring raceway 11b on the inner peripheral surface or quenching and hardening a necessary portion of the inner peripheral surface on the taken out second intermediate material 46. The post-processing such as cutting processing, heat treatment processing, grinding processing, etc. is performed, and then combined with other members to form a wheel bearing rolling bearing unit as shown in FIGS.

If the second intermediate material 46 having the coupling flange 12 is manufactured as described above, the outer ring 6 can be manufactured at a low cost while ensuring the required accuracy. That is, since the outer shape of the second intermediate material 46 can be close to the outer ring 6 in the completed state (with high accuracy), the machining allowance in the subsequent cutting process is reduced, and the time required for the cutting process is shortened. The yield of the material can be improved. The processing from the intermediate material 40 to the second intermediate material 46 is performed by side extrusion, which is a kind of cold forging, but can be performed with a relatively low load, and the equipment investment and operation cost are reduced. It can be suppressed. And the intensity | strength of the obtained outer ring | wheel 6 can fully be enlarged.
However, in order to obtain a better quality outer ring 6, it has been found by the present inventors that it is necessary to improve the side extrusion process. This point will be described below.

  When a cylindrical member provided with a protruding portion is processed by side extrusion as shown in FIG. 6, a recess is formed in a portion of the inner peripheral surface of the cylindrical member that is present on the inner diameter side of the protruding portion. May be formed. For example, when the second intermediate material 46 is processed from the intermediate material 40, a part of the inner peripheral surface of the second intermediate material 46 aligned with the inner diameter side of the coupling flange 12 as shown in FIG. In addition, the recesses 50 and 50 may be formed. Such recesses 50, 50 are not always formed, but during processing, such as the thickness of the material and the ease of flow of the metal material into the radial space 49 where the coupling flange 12 is to be processed. It is formed by the following mechanism according to the balance of various conditions.

  That is, when the connecting flange 12 is formed by the side extrusion, as shown by an arrow in FIG. 8, it extends radially outward from the main body portion (cylindrical portion) of the second intermediate material 46. The metal material flows toward the connecting flange 12. Along with this flow, the metal material that is to be included in the main body portion and exists on the inner diameter side of the coupling flange 12 is also pulled outward in the radial direction. As a result, the concave portions 50 and 50 are formed in a portion of the inner peripheral surface of the second intermediate material 46 that is aligned with the inner diameter side of the coupling flange 12.

  If such concave portions 50 are left unattended, it is difficult to ensure the strength of the obtained outer ring 6 due to stress concentration, so it is necessary to remove it. However, in order to remove the recesses 50 and 50, it is necessary to increase the machining allowance in the cutting process in the subsequent process, and due to the increase in time required for the cutting process and the decrease in the yield of the material. The manufacturing cost of the outer ring 6 will be increased. And since the said recessed parts 50 and 50 are formed in the inner peripheral surface of the said 2nd intermediate raw material 46 nonuniformly over the perimeter, the cutting condition at the time of removing this recessed part 50 and 50 by cutting is as follows. It becomes intermittent and it is difficult to ensure the life of cutting tools such as tools. Therefore, also from this aspect, the manufacturing cost of the outer ring 6 is increased.

  The thickness of the intermediate material 40 in the radial direction may be increased if the above-described recesses 50 are merely prevented. If the wall thickness is increased, the material is supplied well to the connecting flange 12 portion, and the distance between the radial space 49 and the inner peripheral surface of the intermediate material 40 is increased. , 50 is less likely to occur. However, when the wall thickness is increased, the force (working load) required for lowering the ram during the side extrusion processing increases. In addition, in order to prevent the weight of the outer ring 6 from increasing unnecessarily, the manufacturing cost increases due to an increase in machining allowance at the time of cutting performed in a subsequent process.

  Patent Documents 1 to 3 describe inventions related to the structure of a hub including a positioning cylinder portion, a mounting flange, an intermediate portion, and a small diameter step portion. However, all of the inventions described in the above-mentioned Patent Documents 1 to 3 relate to a structure for enabling easy processing or installation of the positioning cylinder part and the mounting flange, and a coupling flange is provided on the outer peripheral surface of the outer ring. However, this does not suggest a technique for enabling accurate processing by cold forging.

JP 2003-25803 A JP 2003-291604 A JP 2004-74815 A

In view of the circumstances as described above, the present invention is, for example, a combination of a plurality of projecting portions provided in a state of projecting in a radial direction from a plurality of locations in the circumferential direction toward a radially outward direction at a part of the outer peripheral surface. The present invention has been invented to realize a manufacturing method capable of processing an outer ring provided with a flange with high accuracy by cold forging and without forming recesses or the like on the inner peripheral surface.

The manufacturing method of the cylindrical member provided with the protruding portion of the present invention is similar to the manufacturing method according to the previous invention described above with reference to FIG. 6, and a mandrel is inserted inside the cylindrical and metal material, A part of the outer peripheral surface of the material is suppressed by the inner peripheral surface of a pair of outer diameter side molds arranged in the axial direction and arranged around the material while suppressing the deformation of the material toward the inner diameter side. This material is compressed in the axial direction in a state where the pressure is suppressed. And by the side extrusion which plastically deforms the part which is not restrained by the inner peripheral surface of the both outer diameter side molds in the remaining part of the outer peripheral surface of this material, a plurality of locations in the circumferential direction of the outer peripheral surface radially outward from, to form a plurality of protrusions projecting radially.

In particular, in the method for manufacturing a cylindrical member having a protruding portion according to the present invention, as the mandrel, a pair of mandrel elements divided into two in the axial direction are abutted on the inner diameter side portion of the portion that becomes the protruding portion. Use things. And while pressing both the mandrel elements elastically in the direction approaching each other, the material is compressed in the axial direction to form the protruding portion, and at the same time, a part of the material is abutted portion of the both mandrel elements. It is made to enter into an annular gap or an annular groove existing in a portion near the outer diameter, and a burr-like surplus portion protruding inward in the radial direction is formed in a portion corresponding to the abutting portion as an intermediate material. Thereafter, the intermediate material is extracted from between the two mandrel elements in a state where the two mandrel elements are separated from each other, and then the burr-like surplus portion is removed.

When carrying out the invention of the manufacturing method of the present invention described above, for example, as in the invention described in claim 2, a cylindrical member provided with a projecting portion is used as an outer ring for constituting a wheel bearing rolling bearing unit. To do. And the protrusion part formed in the outer peripheral surface is taken as the flange part for couple | bonding and fixing this outer ring | wheel to a suspension apparatus.
When the invention described in claim 2 is carried out, as in the invention described in claim 3, for example, the outer ring is a rear combined type with rolling elements arranged in double rows on the inner diameter side of the outer ring. A double row outer ring raceway for providing a contact angle is provided on the inner peripheral surface. At least one of the outer ring raceways is formed simultaneously with the processing of the flange portion by the outer peripheral surface of at least one mandrel element.

According to the manufacturing method of the cylindrical member having the protruding portion of the present invention configured as described above, for example , a state in which a part of the outer peripheral surface protrudes radially outward from a plurality of locations in the circumferential direction. The outer ring provided with the coupling flange composed of a plurality of projecting portions provided in (5) can be processed stably with high accuracy by cold forging while preventing a recess or the like from being formed on the inner peripheral surface. That is, the manufacturing method of the present invention is a cylindrical member provided with a projecting portion such as an outer ring constituting a wheel bearing rolling bearing unit for the same reason as in the manufacturing method of the prior invention shown in FIG. Can be manufactured at low cost while ensuring the required accuracy.

Furthermore, according to the manufacturing method of the present invention, a gap (an annular gap or an annular gap) is formed on the inner diameter side of a portion where a protruding portion such as a coupling flange is to be formed, corresponding to the abutting portion between the tip surfaces of a pair of mandrel elements. Groove) . Then, during the side extrusion process for forming the protruding portion, a part of the metal material constituting the cylindrical member enters the gap, and a burr-like surplus portion protruding inward in the radial direction is formed. Form. In short, the presence of this gap causes a flow inward in the radial direction in a part of the metal material whose axial position corresponds to the protrusion. That is, when the flow of the metal material at the portion corresponding to the protruding portion at the time of side extrusion processing is seen, in the above invention, from the outer peripheral surface to the inner peripheral surface (over the entire thickness). The radially outward flow was dominant. On the other hand, in the case of the present invention, the flow inward in the radial direction is dominant at least in the vicinity of the inner peripheral surface.

  As a result, no concave portion is generated in a portion corresponding to the inner diameter side of the protruding portion in the inner peripheral surface of the intermediate material. The burr-like surplus part needs to be removed by post-processing such as punching and turning, but this burr-like surplus part is thin and small in volume, and has a shape that is continuous over the entire circumference. Therefore, the labor required for the removal is simple, and the volume of the portion to be scrapped is very small (the material yield reduction is very small). Moreover, in order to form the said burr-like surplus part in the butt | matching part of a pair of mandrel elements, the said intermediate material which formed the said protrusion part and the burr-like surplus part by the said side extrusion process is the said both mandrel elements. Can be extracted from between these two mandrel elements. On the other hand, if only the prevention of the formation of the concave portion is taken into consideration, a concave groove may be formed in a portion corresponding to the inner diameter side of the protruding portion on the outer peripheral surface of the integral mandrel. However, in this case, the metal material that has flowed to the inner diameter side with the side extrusion process meshes with the concave groove, so that the intermediate material having the protruding portion cannot be taken out.

1 to 3 show an example of an embodiment of the present invention . First, FIG. 1 shows all steps for processing a cylindrical material 51 into a third intermediate material 52 having a shape close to the outer ring 6. The material 51 shown in FIG. 1A is first an intermediate material 40 having a stepped outer peripheral surface as shown in FIG. 1B by forward extrusion, which is a type of cold forging. Processed into (the material described in the claims). This forward extrusion process is performed by pushing the material 51 into an outer mold having a stepped inner peripheral surface in a state where the material 51 is fitted on a cylindrical mandrel. The forward extrusion process is disclosed in the above-mentioned Japanese Patent Application No. 2004-298585, and is not related to the gist of the present invention.

  The intermediate material 40 is plastically deformed by side extrusion, which is a feature of the present invention, to form a second intermediate material 46a (intermediate material described in claims) as shown in FIG. . The side extrusion is basically performed in the same manner as in the case of the prior invention shown in FIG. 6 described above, but the points different from the prior invention will be described in detail later with reference to FIG. explain. Further, on the inner peripheral surface of the second intermediate material 46a obtained by carrying out the present invention, the second intermediate material 46 (left half part in FIG. 6) obtained by carrying out the above invention is defined. In contrast, an inward ridge-shaped burr-like surplus portion 53 exists at the inner diameter side portion of the coupling flange 12 that is a projecting portion at an intermediate portion of the inner peripheral surface. Accordingly, the burr-like surplus portion 53 is removed by punching or turning with a press to obtain a third intermediate material 52 as shown in FIG. This third intermediate material 52 is formed after the other (axially inner) outer ring raceway 11b (see FIGS. 4 to 5) is formed on the inner peripheral surface, and necessary portions of the inner peripheral surface are quenched and hardened. After processing (post-processing such as necessary cutting, heat treatment, and grinding), it is combined with other members to form a rolling bearing unit for supporting a wheel as shown in FIGS.

Next, a side extrusion process in which the intermediate material 40 is plastically deformed to form the second intermediate material 46a, which is the main point of the present invention, will be described with reference to the manufacturing apparatus shown in FIG. The manufacturing apparatus shown in FIG. 2 is basically the same as the manufacturing apparatus according to the previous invention shown in FIG. 6 described above, with the right half part immediately before the start of processing and the left half part processed. Each state immediately after the end is shown. Therefore, the same reference numerals are given to the same parts as those in the manufacturing apparatus according to the above-described invention, and redundant description will be omitted. Hereinafter, the description will focus on the parts that are different from the manufacturing apparatus according to the above-described invention. In the case of a manufacturing apparatus used in the manufacturing method of the present invention, the mandrel 29a is constituted by an upper mandrel element 54 and a lower mandrel element 55 which are divided into two in the vertical direction. Both the upper and lower mandrel elements 54 and 55 are in a cylindrical shape in which the butted ends have the same outer diameter, and are arranged concentrically with each other.

  Of these, the lower mandrel element 55 is fixed to the upper surface of the central portion of the lower plate 25 concentrically with the lower mold 32. The lower mandrel element 55 is fixed to the upper surface of the lower plate 25 in the same manner as the manufacturing apparatus according to the above invention fixes the mandrel 29 to the upper surface of the lower plate 25. On the other hand, the upper mandrel element 54 is supported (suspended) below the upper plate 36 and concentrically with the upper die 37 so that the upper mandrel element 54 can be slightly lifted with respect to the upper plate 36. That is, the upper part of the upper mandrel element 54 is fitted and held inside the upper punch 43 fixed to the lower surface of the upper plate 36 so as to be able to move up and down by a predetermined amount. Further, a second elastic member 56 is provided between the upper end surface of the upper mandrel element 54 and the center of the lower surface of the upper plate 36, and an elastic force in a downward direction is applied to the upper mandrel element 54. Yes. The second elastic member 56 can be made of an elastomer such as a compression coil spring or rubber, similarly to the elastic member 39 provided between the upper surface of the upper die 37 and the lower surface of the upper plate 36. Alternatively, a downward elastic force may be applied to the upper mandrel element 54 using gas pressure or hydraulic pressure.

  Further, the lower surface center portion of the upper mandrel element 54 and the upper surface center portion of the lower mandrel element 55 are slightly (for example, about 0.2 to 1 mm) in axis compared to the portions near the outer diameter of the respective surfaces. It protrudes in the direction. Therefore, in a state where the lower surface of the upper mandrel element 54 and the upper surface of the lower mandrel element 55 are in contact with each other, the gap between the outer diameter portions of both surfaces is thin (the axial thickness is about 0.4 to 2 mm). A) annular gap 57 is formed over the entire circumference. The width dimension of the annular gap 57 in the radial direction is not particularly limited. About 1 to 2 mm is sufficient. Further, a chamfer is formed on the outer peripheral edge of the lower surface of the upper mandrel element 54 and the upper surface of the lower mandrel element 55, and an annular groove formed by combining these two chamfers is formed in place of the annular gap 57. It can also be.

In the side extrusion process in which the intermediate material 40 is plastically deformed to form the second intermediate material 46a by the manufacturing apparatus of the present example configured as described above, first, the intermediate material 40 is formed as shown in FIG. As shown in the right half of the figure, it is mounted between the lower mold 32 and the upper mold 37. This mounting operation is performed with the upper die 37 and the upper punch 43 raised together with the ram of the press machine.
Next, the ram that has been raised is lowered, and first, as shown in the right half of FIG. 2, a portion near the upper surface outer diameter of the lower die 32 and a portion near the lower surface outer diameter of the upper die 37 And the lower surface of the upper mandrel element 54 and the upper surface of the lower mandrel element 55 are abutted. These faces may be matched at the same time or slightly before and after.

Next, the ram is further lowered, and the intermediate material 40 is strongly pressed toward the lower punch 30 by the upper punch 43. At this time, the elastic member 39 and the second elastic member 56 are elastically compressed. In this state, a portion near the upper surface outer diameter of the lower die 32 and a portion near the lower surface outer diameter of the upper die 37 are formed so that the lower surface center portion of the upper mandrel element 54 and the upper surface center portion of the lower mandrel element 55 are located. Only the upper punch 43 is lowered while being in close contact with each other.
As a result, while the lower half portion of the intermediate material 40 is plastically deformed, the surface pressing portion of the inner peripheral surface of the lower half portion of the lower mold 32 and the outer peripheral surface of the lower mandrel element 55 is compressed. It is pushed into the cylindrical space 48 between the lower part than 35. Then, the lower half of the intermediate material 40 is plastic processed into a shape following the cylindrical space 48. In this state, one (axially outer) outer ring raceway 11a is formed.

The lowering of the upper punch 43 continues until the lower half of the intermediate material 40 is completely pushed into the cylindrical space 48. As a result, a part of the metal material constituting the intermediate material 40 flows (flows) into the radial space 49 formed by the lower concave portion 34 and the upper concave portion 42, and a plurality of circumferential directions of the outer peripheral surface are formed. The coupling flange 12 is formed of a plurality of projecting portions projecting radially outward from the location in the radial direction . In this state, the intermediate material 40 is processed into the second intermediate material 46a that is closer to the shape of the outer ring 6.
When carrying out the present invention, a part of the metal material flows into the radial space 49 and also into the annular gap 57. Then, the burr-like surplus portion 53 is formed corresponding to the annular gap 57.
Thereafter, the ram is raised again, and the upper die 37 is removed from the periphery of the second intermediate material 46a, and the upper mandrel element 54 is similarly removed from the inner side. Next, the second intermediate material 46 a on which the coupling flange 12 is formed is taken out from the inside of the lower mold 32. This removal operation is performed by raising the lower punch 30. As described above, the second intermediate material 46a taken out is post-processed to form the outer ring 6.

As described above , according to the manufacturing method of this example, the outer ring 6 provided with the coupling flange 12 on the outer peripheral surface is accurately formed by cold forging, and the concave portion 50 as shown in FIG. It can be processed stably without causing 50 defects. That is, according to the manufacturing method of the present example, the annular gap is formed on the inner diameter side of the portion where the coupling flange 12 is to be formed, corresponding to the abutting portion between the front end surfaces of the upper and lower mandrel elements 54 and 55. 57 exists. During the side extrusion for forming the coupling flange 12, a part of the metal material constituting the intermediate material 40 to the second intermediate material 46a enters the annular gap 57, and the radial direction The burr-like surplus portion 53 protruding inward is formed. In short, the presence of the annular gap 57 causes a flow inward in the radial direction as shown by an arrow in FIG. 3 in a part of the metal material whose axial position corresponds to the coupling flange 12. The That is, when the flow of the metal material at the portion corresponding to the connecting flange 12 in the side extrusion process is viewed, the prior invention shown in FIG. 6 described above extends from the outer peripheral surface to the inner peripheral surface. The flow toward the outside in the radial direction was dominant (over the entire thickness). On the other hand, in the case of this example, in order to flow into the annular gap 57 at least in the vicinity of the inner peripheral surface, the flow directed inward in the radial direction becomes dominant.

  As a result, in the inner peripheral surface of the second intermediate material 46a, the concave portions 50 and 50 as shown in FIG. 7 do not occur in the portion corresponding to the inner diameter side of the coupling flange 12. The burr-like surplus portion 53 needs to be removed by post-processing such as punching and turning, but this burr-like surplus portion 53 is thin and has a small volume, and has a continuous shape over almost the entire circumference. Therefore, the labor required for the removal is simple, and the volume of the portion to be scrapped is very small (the decrease in the yield of the material is very small). Further, in order to form the burr-like surplus portion 53 at the abutting portion of both the upper and lower mandrel elements 54, 55, the coupling flange 12 and the burr-like surplus portion 53 are formed by the side extrusion. The second intermediate material 46a can be extracted from between the mandrel elements 54, 55 by raising the upper mandrel element 54 and separating the mandrel elements 54, 55.

  Unlike the illustrated example, a chamfer is formed on the outer peripheral edge of the lower surface of the upper mandrel element 54 and the upper surface of the lower mandrel element 55, and an annular groove formed by combining these two chamfers is formed. Even when it is provided, a flow inward in the radial direction can be induced in the vicinity of the inner peripheral surface of the intermediate material 40 to the second intermediate material 46a. In this case, even if the volume of the annular groove is small, if the metal material flows into the annular groove, the upper mandrel element 54 tends to rise against the elasticity of the second elastic member 56. The flow inward in the radial direction can be induced to such an extent that the concave portions 50 can be sufficiently prevented.

Production method of the present invention, radially outward from the plurality of circumferential locations of the outer peripheral surface, if the tubular member having a plurality of protrusions projecting radially, rolling wheel support, such as shown This is not limited to the outer ring constituting the bearing unit.
Although not shown in the drawing, the structure shown in FIG. 2 is provided with a protruding portion that extends further downward from the inner diameter of the lower end surface of the upper punch 43, and the outer ring on the inner side in the axial direction is provided at the lower end surface portion of the protruding portion. If the second surface pressing portion for forming the track 11b is provided, a double row inner ring raceway or a portion having a shape close to the double row inner ring raceway can be processed on the inner peripheral surface of the second intermediate material. . And post-processing can be simplified more and the manufacturing cost of the outer ring | wheel which comprises the rolling bearing unit for wheel support can be reduced further.

Sectional drawing and end elevation which show one example of embodiment of this invention in order of a process process. Sectional drawing which shows an example of the implementation condition of a side extrusion process with the state just before a process start, and the state immediately after completion | finish of a process. The end view and sectional drawing which show the movement condition of a metal material in the state which implements a side extrusion process by this invention. Sectional drawing which shows the 1st example of the rolling bearing unit for wheel support provided with the outer ring which is an example of the cylindrical member provided with the protrusion part used as the object of the manufacturing method of this invention in the state assembled | attached to the knuckle. Sectional drawing which shows the 2nd example. Sectional drawing which shows the state which made the outer ring which comprises the wheel bearing rolling bearing unit considered previously by the side extrusion process in the state just before a process start, and the state just after completion | finish of a process. The end view and sectional drawing of the outer ring | wheel which comprise the rolling bearing unit for wheel support shown in the state which exaggerated the defect which arises with the manufacturing method considered previously. In order to explain the reason why the defect occurs, an end view and a cross-sectional view showing a movement state of the metal material.

DESCRIPTION OF SYMBOLS 1 Wheel 2 Rotor 3 Knuckle 4 Support hole 5, 5a Wheel support hub unit 6 Outer ring 7 Bolt 8, 8a Hub 9 Stud 10 Nut 11a, 11b Outer ring track 12 Coupling flange 13, 13a Hub body 14 Inner ring 15 Mounting flange 16a, 16b Inner ring raceway 17 Small diameter step portion 18 Caulking portion 19 Rolling element 20a, 20b Seal ring 21 Spline hole 22 Outer ring for constant velocity joint 23 Spline shaft 24 Nut 25 Lower plate 26 Lower holding cylinder 27 Holding plate 28 Center hole 29, 29a Mandrel 30 Lower punch 31 Lower support block 32 Lower mold 33 Center hole 34 Lower recess 35 Surface pressing part 36 Upper plate 37 Upper mold 38 Upper holding cylinder 39 Elastic member 40 Intermediate material 41 Center hole 42 Upper recess 43 Upper punch 44 Outer diameter Side punch 45 Inner diameter side punch 4 , 46a second intermediate material 47 stepped portion 48 cylindrical space 49 radially space 50 recess 51 Material 52 third intermediate material 53 burr-like excess thickness portions 54 upper mandrel element 55 lower mandrel element 56 second elastic member 57 annular gap

Claims (3)

A mandrel is inserted inside a cylindrical metal material to prevent the material from deforming to the inner diameter side, and a pair of outer diameters arranged around the material and divided in two in the axial direction. By compressing this material in the axial direction with a part of the outer peripheral surface of this material held down by the inner peripheral surface of the side mold, the inner part of both outer diameter side molds is retained by the remainder of the outer peripheral surface of this material. the side extrusion to plastically deform the portion not suppressed radially outwards by the peripheral surface, radially outward from the plurality of circumferential locations of the outer peripheral surface, forming a plurality of protrusions projecting radially A method of manufacturing a cylindrical member having a protruding portion, wherein the mandrel is formed by abutting a pair of mandrel elements divided into two in the axial direction at the inner diameter side portion of the protruding portion. The direction of approaching these mandrel elements to each other While elastically pressed, by compressing the material in the axial direction, and at the same time to form the protrusions, the annular gap or present some of this material to the outer径寄Ri portion of the butted portion of both the mandrel element After entering the annular groove and forming an intermediate material by forming a burr-like surplus portion protruding radially inward at the portion corresponding to the abutting portion, the intermediate material is separated with the two mandrel elements separated from each other. A method for producing a cylindrical member having a protrusion, wherein the burr-like surplus portion is removed after being extracted from between these two mandrel elements.   The cylindrical member provided with the protruding portion is an outer ring for constituting a wheel bearing rolling bearing unit, and the protruding portion formed on the outer peripheral surface is a flange portion for coupling and fixing the outer ring to the suspension device. The manufacturing method of the cylindrical member provided with the protrusion part described in Claim 1.   The outer ring has a double-row outer ring raceway on the inner peripheral surface for imparting a contact angle of the rear combined type to the rolling elements arranged in a double row on the inner diameter side of the outer ring, and at least one of the mandrel elements The manufacturing method of the cylindrical member provided with the protrusion part according to claim 2, wherein one outer ring raceway of the two outer ring raceways is formed simultaneously with the processing of the flange portion by the outer peripheral surface.

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