JP5056631B2 - Manufacturing method of shaft - Google Patents

Description

  The present invention relates to a method for manufacturing a shaft, and more specifically, a first inner diameter portion capable of setting a cylindrical workpiece having a hollow portion at the center of an axis, and a shaft for a shaft restriction having a smaller diameter than the first inner diameter portion. The outer diameter of the first die is formed so that the inner diameter portion of the workpiece is coaxially formed and the shaft end surface of the workpiece set on the first inner diameter portion can be pressed toward the second inner diameter portion. A pressing portion having substantially the same diameter as the inner diameter portion of the inner diameter portion and a convex portion inserted into the hollow portion with an outer diameter smaller than the inner diameter of the hollow portion of the workpiece when the workpiece is pressed by the pressing portion are coaxial. The punch is formed by using a press machine, and the workpiece is pressed to have a post-processing recess having an inner diameter substantially the same as the outer diameter of the protrusion of the punch at the center of the shaft, and the outer diameter is A first outer diameter portion having substantially the same diameter as the first inner diameter portion and a second diameter having substantially the same diameter as the second inner diameter portion. The method of manufacturing a shaft for manufacturing a shaft having a diameter.

Conventionally, this type of shaft is manufactured by drilling (drilling process) in the center of a cylindrical rough material to form a through hole, and inserting the drilled rough material with this through hole. The inner diameter is larger than the through hole by cold forging (backward extrusion) using a die that can be fitted into the through hole and a punch that has a shaft portion with a larger outer diameter. The step (concave part) is formed stepwise on the same axis to form a stepped coarse material, which is inserted into a die composed of an insertion portion on which the stepped coarse material is set and a tapered throttle portion, and a through hole in the stepped coarse material. It has been proposed to manufacture a shaft by performing shaft drawing by cold forging (shaft drawing) using a punch in which a shaft portion to be joined and a shaft portion fitted to a large diameter portion are formed in a step shape. (See Patent Document 1).
JP 07-214228 A

  Thus, the process burden can be reduced by forming the concave portion (large diameter portion) of the cylindrical workpiece before the axial drawing by the press working by cold extrusion (cold forging) described above. When press working is used, the ratio of the cross-sectional area of the inner diameter of the concave part of the work that can be extruded backward to the cross-sectional area of the outer diameter of the work (cross-sectional area ratio) is limited. In some cases, the inner diameter of the concave portion of the workpiece cannot be pressed so as to coincide with the inner diameter of the concave portion of the shaft of the finished product within a limited range. In this case, it can be considered that the concave portion of the workpiece is formed by cutting, but the process burden increases and the productivity is lowered.

  The shaft manufacturing method of the present invention is mainly intended to reduce the process load and further improve productivity.

  The shaft manufacturing method of the present invention employs the following means in order to achieve the above-mentioned main object.

The manufacturing method of the shaft of the present invention includes:
A die in which a first inner diameter portion capable of setting a cylindrical workpiece having a hollow portion at the center of the shaft and a second inner diameter portion for an axial diaphragm having a smaller diameter than the first inner diameter portion are formed on the same axis. And a pressing portion whose outer diameter is substantially the same as the inner diameter of the first inner diameter portion so that the shaft end surface of the workpiece set on the first inner diameter portion can be pressed toward the second inner diameter portion. Using a press machine, which has a punch formed coaxially with a convex part inserted into the hollow part with an outer diameter smaller than the inner diameter of the hollow part of the work as the work is pressed by the pressing part The workpiece is pressed to have a post-processing recess having an inner diameter that is substantially the same as the outer diameter of the convex portion of the punch at the center of the shaft, and an outer diameter that is substantially the same as the first inner diameter portion. Production of a shaft for producing a shaft having an outer diameter portion and a second outer diameter portion having substantially the same diameter as the second inner diameter portion. There is provided a method,
Crushed by pressing the axial end surface of the workpiece with the pressing portion of the punch to reduce the inner diameter of the hollow portion of the workpiece to the outer diameter of the convex portion of the punch, and forming the recessed portion after processing, Extrusion forming the first outer diameter portion and the second outer diameter portion by pressing the shaft end surface of the workpiece with the pressing portion of the punch to push the workpiece into the second inner diameter portion; The shape of the workpiece and the shape of the first inner diameter portion of the die are set so that the load required for the extrusion molding is larger than the load required for the bush molding so that the workpiece is formed in one stroke. The press machine is used for press working.

In this shaft manufacturing method of the present invention, the shaft end surface of the workpiece is pressed by the pressing portion of the punch, and the inner diameter of the hollow portion of the workpiece is reduced to the outer diameter of the convex portion of the punch to form a post-processing recess. And the extrusion molding which pushes the shaft end surface of the workpiece with the pressing portion of the punch to push the workpiece into the second inner diameter portion to form the first outer diameter portion and the second outer diameter portion. The workpiece is pressed using a press machine with the shape of the workpiece and the shape of the die set so that the load required for extrusion molding is greater than the load required for the bush molding so as to be performed in one stroke. Thereby, it is possible to form the recesses and the first and second outer diameter portions after processing by performing the bush molding and the extrusion molding only by making one stroke of the press machine. As a result, the process burden can be reduced and the productivity of the shaft can be further improved.

  In such a shaft manufacturing method of the present invention, the hollow part of the workpiece is formed with a pre-machining concave part having a larger inner diameter than the post-machining concave part and a through hole provided in the bottom of the pre-machining concave part on the same axis. The convex portion of the punch has an outer diameter that is smaller than the inner diameter of the through-hole and an outer diameter that is larger than the inner diameter of the through-hole and smaller than the inner diameter of the recess before processing. It can also be formed. If it carries out like this, the process burden at the time of forming the long hole which penetrates an axial center in a shaft can be reduced more.

  Moreover, in the manufacturing method of the shaft of this invention, the recessed part before a process of the said workpiece | work can also be shape | molded by press work. In this way, the process burden can be further reduced.

  Furthermore, in the method for manufacturing a shaft of the present invention, the workpiece may be pressed using cold forging. In this way, the process burden can be further reduced.

  In the shaft manufacturing method of the present invention, the press machine may be used in an intermediate process among a plurality of processes performed by transfer-type or tandem-type press working.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of the configuration of the press apparatus 10, FIG. 2 is an explanatory diagram showing an example of a manufacturing process of the shaft, and FIG. 3 shows each of the steps from the coarse material 20a to the shaft as a finished product. FIG. 4 is a perspective view of the intermediate members 20b to 20f formed in the process, and FIG. 4 is a cross-sectional view illustrating the cross sections of the coarse member 20a and the intermediate members 20b to 20f of FIG. As shown in FIG. 1, the pressing device 10 sequentially feeds the coarse material 20 a to the respective steps A to E, and sequentially presses them with the press machines 30 a to 30 e arranged in the respective steps A to E. It is configured as a transfer-type pressing device for manufacturing a shaft having an elongated hole. A slide 12 which is arranged at the upper part and can be moved up and down by hydraulic drive, a bolster 14 arranged at the lower part, and a coarse material 20a are arranged in each step A. To E, and includes upper molds 32 a to 32 e fixed to the slide 12, and lower molds 34 a to 34 e fixed to the bolster 14. In addition, the shaft manufactured by the press apparatus 10 is used as a drive shaft of an automatic transmission, for example. Hereinafter, the process of manufacturing the shaft by the press apparatus 10 will be described with reference to FIGS. 3 and 4 using the process diagram of FIG.

  As a manufacturing process of the shaft, as shown in the process diagram of FIG. 2, first, the pretreatment necessary for the coarse material 20a is performed (step S100). The coarse material 20a is formed as a cylindrical member having an outer diameter of value W1 (see FIG. 3 (a) and FIG. 4 (a)), low carbon steel, low carbon alloy steel, aluminum, aluminum alloy, copper. Materials that can be cold forged, such as copper alloys, are used. The reason why the outer diameter is set to the value W1 will be described later. Examples of the predetermined pretreatment performed on the rough material 20a include softening annealing, shot blasting, and bondage treatment for appropriately performing cold forging in a subsequent process. Note that shot blasting is a process of removing scales on the surface of the material and performing surface polishing by spraying countless abrasive grains at high speed. Bonding is a lubrication treatment for reducing the coefficient of friction of the material surface. For example, a chemical conversion film (for example, a phosphate film) is formed on the surface of the material, and the surface of the chemical conversion film is made of metal soap. Is performed by coating.

  Next, backward extrusion molding by cold forging is performed on the coarse material 20a using the press 30a (step S110). FIG. 3B shows a perspective view of the intermediate member 20b obtained by the backward extrusion molding, and FIG. 4B shows a cross-sectional view thereof. A recess 22 having an inner diameter W2 is formed in the intermediate material 20b by backward extrusion. In cold forging, since the ratio of the inner diameter area of the recess 22 to the outer diameter area of the coarse material 20a needs to exceed a predetermined ratio (for example, 25%), the recess 22 is formed into a relatively small inner diameter by cold forging. It is difficult. In the embodiment, the recess 22 is formed with a relatively large inner diameter that can be cold forged, and the recess 22 is reduced in diameter by a subsequent process. This diameter reduction process will be described later. When the rear extrusion is performed, a punching process for forming the through hole 22 at the bottom of the recess 22 is performed on the intermediate material 20b after the rear extrusion using the press 30b (step S120). FIG. 3C is a perspective view of the intermediate member 20c obtained by the hole punching process, and FIG. 4C is a cross-sectional view thereof.

  And the 1st axis | shaft draw forming by cold forging is performed with respect to the intermediate material 20c using the press 30c (process S130). A perspective view of the intermediate member 20d obtained by the first axial drawing is shown in FIG. 3 (d), and a sectional view thereof is shown in FIG. 4 (d). As shown in the drawing, the intermediate material 20d is formed with the first long hole 22a and the second long hole 24a from the recess 22 and the through hole 24 by the first axial drawing.

  FIG. 5 is a block diagram showing an outline of the configuration of the press machine 30c, and FIG. 6 is an enlarged view of an area A in FIG. As shown in FIGS. 5 and 6, the press machine 30 c used for the first shaft drawing is configured by an upper mold 32 c fixed to the slide 12 and a lower mold 34 c fixed to the bolster 24. The upper mold 32c is fixed to the slide 12 and has a pressing portion 42 that can press the shaft end surface of the intermediate material 20c with an outer diameter P1 that is substantially the same as the outer diameter W1 of the intermediate material 20c as a workpiece by the vertical movement of the slide 12. The punch 40 is provided with an elongated protruding portion 44 protruding from the axial center of the pressing portion 52. The projecting portion 44 of the punch 40 has a thick outer diameter P2 having a diameter smaller than the inner diameter W2 of the concave portion 22 of the intermediate material in order to form an elongated hole at the axial center with respect to the intermediate material 20c by the first axial drawing. A shaft portion 44a and a thin shaft portion 44b having an outer diameter P3 smaller than the outer diameter P2 of the thick shaft portion 44a and slightly smaller than the inner diameter W3 of the through hole 24 of the intermediate member 20c are formed coaxially. The lower die 34c has a placement portion 52 on which the intermediate material 20c can be placed with an inner diameter D1 that is substantially the same as the outer diameter W1 of the intermediate material 20c, and downward from the inner diameter D1 of the placement portion 52 to a smaller inner diameter D2. And a die 50 in which a tapered portion 54 formed in a tapered shape so as to gradually reduce the diameter and a cylindrical portion 56 having an inner diameter D2 are formed on the same axis.

  In the press machine 30c configured in this way, the intermediate material 20c is set on the mounting portion 52 of the lower die 34c, the upper die 32c is moved up and down by driving the slide 12, and the shaft of the intermediate material 20c is pressed by the pressing portion 42 of the punch 40. By pressing the end face, the material is crushed in a state supported by the taper portion 54 and is caused to flow in the radial direction, whereby a part of the inner diameter W2 of the concave portion 22 of the intermediate member 20c is changed to the outer diameter P2 of the thick shaft portion 44a. Reducing the diameter to a corresponding diameter, and extruding the material from the taper portion 54 to flow downward, a part of the outer diameter W1 of the intermediate member 20c is reduced to a diameter corresponding to the inner diameter D2 of the cylindrical portion 56. At the same time, shaft drawing is performed to form a first long hole 22a corresponding to the concave portion 22 and a second long hole 22b corresponding to the through hole 24 guided by the thin shaft portion 44b. FIG. 7 shows the relationship between the outer diameter W1 of the intermediate member 20c, the molding load required for the bushing molding (the bushing load), and the molding load required for the shaft drawing (extrusion molding) (shaft drawing load). In the embodiment, as illustrated, the outer diameter W1 of the intermediate member 20c (the outer diameter W1 of the coarse member 20a) is designed so that the axial throttle load is sufficiently larger than the bush load. Thereby, a bush molding and a shaft drawing can be performed in this order by one stroke.

  FIG. 8 is an explanatory view showing a state in which the intermediate material 20c is formed by the first shaft drawing. FIG. 8A shows the intermediate material 20c before deformation. When the shaft end surface of the intermediate member 20c is pressed by the pressing portion 42 of the punch 40, the material starts to flow. At this time, since the outer diameter W1 of the intermediate member 20c as the workpiece (the inner diameter D1 of the mounting portion 52 of the die 50) is designed to be smaller than the axial drawing load, the material is smaller than the tapered portion 54. Instead of flowing downward, it flows in the radial direction, and the recess 22 of the intermediate member 20c is reduced in diameter (see FIGS. 8B and 8C). When the concave portion 22 of the intermediate member 20c is reduced to a diameter corresponding to the outer diameter P2 of the thick shaft portion 44a and the flow of the material in the radial direction is completed, the material escape field is only below the tapered portion 54. It is pushed downward with a guide by the protruding portion 44 (thick shaft portion 44a and thin shaft portion 44b), and is formed into a shaft shape while forming the first long hole 22a and the second long hole 24a at the shaft center. (See FIG. 8 (d) and FIG. 8 (e)).

  When the first axial drawing is performed in this way, the second axial drawing is performed in which a known axial drawing is performed using the press 32d in order to further increase the axial length of the intermediate material 20d obtained by the first axial drawing. (Step S140), the flange 26 is formed by upsetting the intermediate material 20e obtained by the second shaft drawing using the press 32e (step S150), and obtained by upsetting. The intermediate member 20f is subjected to a predetermined post-process such as a cleaning process for cutting the surface or removing the coated lubricant (step S160) to complete the shaft. FIG. 3E shows a perspective view of the intermediate member 20e obtained by the second axial drawing, and FIG. 4E shows a cross-sectional view thereof. Further, a perspective view of the intermediate member 20f obtained by upsetting is shown in FIG. 3 (f), and a cross-sectional view thereof is shown in FIG. 4 (f). In addition, since upsetting is a known technique, the description thereof is omitted.

  According to the shaft manufacturing method of the embodiment described above, the pressing portion 42 that presses the shaft end surface of the intermediate member 20c with the outer diameter P1 substantially the same as the outer diameter W1 of the intermediate member 20c as a workpiece and the intermediate member 20c. An upper die 32c having a punch 40 in which a protruding portion 44 having a thick shaft portion 44a having an outer diameter P2 having a diameter smaller than the inner diameter W2 of the recess 22 is formed on the same axis, and substantially the same as the outer diameter W1 of the intermediate member 20c. A placing portion 52 for placing the intermediate member 20c with an inner diameter D1 having a diameter, a tapered portion 54, and a lower die 34c having a die 50 in which a cylindrical portion 56 having an inner diameter D2 smaller than the inner diameter D1 is formed coaxially. The machine 30c is configured so that the outer diameter W1 of the intermediate member 20c and the inner diameter D1 of the mounting portion 52 of the die 50 are designed so that the axial drawing load required for the axial drawing is larger than the thick load required for the forming. , A busi shaping and axial drawing can be carried out by one stroke in this order. As a result, the process burden can be further reduced, and the productivity of the shaft can be further improved.

  In the shaft manufacturing method according to the embodiment, the shaft manufacturing method has been described as being applied to the manufacturing method of the shaft having the first and second elongated holes 22a and 24a penetrating the shaft center. It does not matter if it is manufactured.

  In the shaft manufacturing method of the embodiment, the concave portion 22 of the intermediate member 20c is formed by backward extrusion using the press machine 20a. However, it may be formed by any other method such as cutting.

  The method of manufacturing the shaft of the example is that the shaft is manufactured by continuously pressing using a transfer-type press device, but the present invention is not limited to this, and the single press machines are arranged in tandem. The shaft may be manufactured by pressing.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the intermediate material 20c having the recess 22 and the through hole 24 at the center of the shaft corresponds to the “work”, the press machine 30c corresponds to the “press machine”, and has substantially the same diameter as the outer diameter W1 of the intermediate material 20c. A die 50 in which a placement portion 52 having an inner diameter D1, a taper portion 54, and a cylindrical portion 56 having an inner diameter D2 smaller than the inner diameter D1 are coaxially formed corresponds to a “die”, and the outer diameter of the intermediate member 20c. From the pressing portion 42 having an outer diameter P1 substantially the same diameter as W1, the thick shaft portion 44a having an outer diameter P2 smaller than the inner diameter W2 of the recess 22 of the intermediate member 20c, and the inner diameter W3 of the through hole 24 of the intermediate member 20c. Further, the punch 40 in which the protruding portion 44 formed of the thin shaft portion 44b having a slightly smaller outer diameter P3 is formed on the same axis corresponds to the “punch”. The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. It is an example for specifically explaining the best mode for doing so, and does not limit the elements of the invention described in the column of means for solving the problem. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  The best mode for carrying out the present invention has been described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and various forms are possible without departing from the spirit of the invention. Of course, it can be implemented.

  The present invention can be used in the shaft manufacturing industry.

1 is a configuration diagram showing an outline of the configuration of a press apparatus 10. FIG. It is explanatory drawing which shows an example of the manufacturing process of a shaft. It is a perspective view of intermediate material 20b-20f shape | molded in each process from the rough material 20a to the shaft as a finished product. It is sectional drawing which shows the cross section of the coarse material 20a of FIG. 3, and the intermediate materials 20b-20f. It is a block diagram which shows the outline of a structure of the press machine 30c. It is the enlarged view to which the A area | region of the press 30c of FIG. 5 was expanded. It is explanatory drawing which shows the relationship between the outer diameter W1 of the intermediate | middle material 20c, the shaping | molding load (bush load) required for a bushing shaping | molding, and the shaping | molding load (axial drawing load) required for axial drawing (extrusion molding). It is explanatory drawing which shows a mode that the intermediate material 20c is shape | molded by 1st axial drawing.

Explanation of symbols

  10 Press machine, 12 slide, 14 bolster, 16 carrier, 20a rough material, 20b-20f intermediate material, 22 recess, 22a first long hole, 24 through hole, 24a second long hole, 26 flange, 30c press Machine, 32a to 32e Upper die, 34a to 34e Lower die, 40 Punch, 42 Pressing part, 44 Protruding part, 44a Thick shaft part, 44b Thin shaft part, 50 Dies, 52 Placement part, 54 Taper part, 56 Cylindrical part .

Claims (4)

A die in which a first inner diameter portion capable of setting a cylindrical workpiece having a hollow portion at the center of the shaft and a second inner diameter portion for an axial diaphragm having a smaller diameter than the first inner diameter portion are formed on the same axis. And a pressing portion whose outer diameter is substantially the same as the inner diameter of the first inner diameter portion so that the shaft end surface of the workpiece set on the first inner diameter portion can be pressed toward the second inner diameter portion. Using a press machine, which has a punch formed coaxially with a convex part inserted into the hollow part with an outer diameter smaller than the inner diameter of the hollow part of the work as the work is pressed by the pressing part The workpiece is pressed to have a post-processing recess having an inner diameter that is substantially the same as the outer diameter of the convex portion of the punch at the center of the shaft, and an outer diameter that is substantially the same as the first inner diameter portion. Production of a shaft for producing a shaft having an outer diameter portion and a second outer diameter portion having substantially the same diameter as the second inner diameter portion. There is provided a method,
In the hollow portion of the workpiece, a concave portion before processing having a larger inner diameter than the concave portion after processing and a through hole provided in the bottom of the concave portion before processing are formed coaxially,
The convex portion of the punch has a step having an outer diameter that is smaller than the inner diameter of the through-hole and an outer diameter that is larger than the inner diameter of the through-hole and smaller than the inner diameter of the recess before processing. Formed,
Crushed by pressing the axial end surface of the workpiece with the pressing portion of the punch to reduce the inner diameter of the hollow portion of the workpiece to the outer diameter of the convex portion of the punch, and forming the recessed portion after processing, Extrusion forming the first outer diameter portion and the second outer diameter portion by pressing the shaft end surface of the workpiece with the pressing portion of the punch to push the workpiece into the second inner diameter portion; The shape of the workpiece and the shape of the first inner diameter portion of the die are set so that the load required for the extrusion molding is larger than the load required for the bush molding so that the workpiece is formed in one stroke. A method for producing a shaft, wherein the press machine is used for press working. Method for producing a shaft according to claim 1, wherein, characterized by formed by pressing the unmachined concave portion of the workpiece. The process according to claim 1 or 2, wherein the shaft, characterized in that pressing the workpiece with cold forging. The press machine, shaft manufacturing method according to claims 1 to 3 any one, characterized by being used in an intermediate step of the plurality of processes performed by pressing the transfer method or tandem.

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