Toothed cylindrical body formation method

Abstract

To reduce possibility that cracks are formed during processing when a flange part is provided at the other end of a cylindrical body.SOLUTION: A toothed cylindrical body formation method comprises a raw shape material formation process and a tooth formation process. A raw shape material is formed in the raw shape material formation process. The raw shape material comprises a cylindrical shank 20 and a flange part 22. The shank 20 has a tooth formation section 130 and the other end section 132. In the tooth formation process, the tooth formation section 130 is pressed against a tooth formation metal mold 108 formed on an outer periphery in the state that at least an end of the other end section 132 on one end side of the shank 20 is movable and the flange part 22 is fixed, whereby a tooth 136 is formed for the tooth formation section 130.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for forming a toothed cylinder. [Background technology]

[0002] Patent Document 1 discloses a method for forming a toothed cylinder. The toothed cylinder is provided with a base material forming step and a teeth forming step. In the base material forming step, a metal plate is subjected to plastic processing so as to form a cylinder. In the teeth forming step, gear teeth are formed in a tooth forming section. The tooth forming section is a section disposed at one end of the cylinder. The gear teeth are formed by plastic processing. In the base material forming step, a cylinder is formed so as to be divided into a tooth forming section, a small outer diameter section, and a step section. The small outer diameter section is disposed on the other end side of the cylinder than the tooth forming section. The small outer diameter section has an outer diameter smaller than that of the tooth forming section. The step section is disposed between the tooth forming section and the small outer diameter section. The step section is a step between the tooth forming section and the small outer diameter section. In the tooth forming step, the tooth forming section is subjected to plastic processing while the step section is supported and the part of the cylinder that is on the other end side of the cylinder than the step section is suspended in the air. According to the method for forming a toothed cylinder disclosed in Patent Document 1, the possibility of cracks occurring during processing is reduced. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-092911 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the invention disclosed in Patent Document 1 has a problem in that when it is difficult to support the stepped section due to the provision of a flange portion at the other end of the cylinder, it becomes difficult to form the gear teeth.

[0005] An object of the present invention is to provide a method for forming a toothed cylinder that reduces the possibility of cracks occurring during processing when a flange portion is provided on the other end of the cylinder. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, according to one aspect of the present invention, a method for forming a toothed cylindrical body includes preform forming steps S300, S304. In the preform forming steps S300, S304, a preform 12, 16 is formed. The preform 12, 16 includes a cylindrical body portion 20, 26. The body portion 20, 26 has a tooth forming section 130, 230 and an other end section 132, 232. The tooth forming section 130, 230 is a section disposed at one end. The other end section 132, 232 is disposed on the other end side of the tooth forming section 130, 230. The method for forming a toothed cylindrical body includes tooth forming steps S302, S306 in addition to the preform forming steps S300, S304. In the tooth forming steps S302, S306, gear teeth 136, 138 are formed on the tooth forming section 130, 230. The gear teeth 136, 138 are formed by plastic processing. The preform 12, 16 has a flange 22 in addition to the body 20, 26. The flange 22 is disposed on the outer edge of the other end of the body 20, 26. The preform forming steps S300, S304 include a material processing step S320 and an other end section forming step S322, S342. In the material processing step S320, a metal material is processed to form a tubular portion 40 having one and the other ends open, and the flange 22. In the other end section forming steps S322, S342, the other end section 132, 232 is formed in the tubular portion 40 prior to the tooth forming steps S302, S306. In the tooth forming steps S302, S306, at least the end of the other end section 132, 232 on one end side of the body 20, 26 is in a movable state and the flange portion 22 is fixed, and the tooth forming section 130, 230 is pressed against the mold 108, 208 arranged on the outer periphery, thereby forming teeth 136, 138 on the tooth forming section 130, 230.

[0007] When the teeth 136, 138 are formed on the tooth forming section 130, 230 in the tooth forming steps S302, S306, the tooth forming section 130, 230 is pressed against the die 108, 208 arranged on the outer periphery. As the tooth forming section 130, 230 is pressed against the die 108, 208 arranged on the outer periphery, stress is applied to each part of the preform 12, 16. When the teeth 136, 138 are formed on the tooth forming section 130, 230 in the tooth forming steps S302, S306, at least the end of the other end section 132, 232 on one end side of the body section 20, 26 is in a movable state and the flange section 22 is in a fixed state. As a result, the stress applied to each part of the preform 12, 16 as the tooth forming section 130, 230 is pressed against the die 108, 208 arranged on the outer periphery is alleviated in the movable part of the other end section 132, 232. Since the difference in stress acting on each portion of the blanks 12, 16 is alleviated and the stress itself is alleviated, the possibility of cracks occurring during processing is reduced.

[0008] In the above-described tooth forming step S302, it is preferable that the teeth 136 are formed on the tooth forming section 130 by pressing the teeth forming section 130 against the dies 108 arranged on the outer periphery of the body portion 20 in sequence from one end side in the state described below. This state is a state in which the body portion 20 is supported so as to prevent buckling, at least the end of the other end section 132 on the one end side of the body portion 20 is in a movable state, and the flange portion 22 is fixed.

[0009] The body portion 20 is supported so as to prevent buckling, and at least one end of the other end section 132 of the body portion 20 on one side is movable, while the flange portion 22 is fixed. As a result, at least one end of the other end section 132 of the body portion 20 on one side is displaced, and the difference in stress applied to each part of the preform 12 is alleviated. Moreover, the body portion 20 is supported so as to prevent buckling. Since the difference in stress is alleviated, it is possible to reduce the possibility that a particularly large stress is applied to any of the parts of the preform 12. Since such a possibility can be reduced, it is possible to reduce the possibility of cracks occurring during processing. Moreover, in this state, the tooth forming section 130 is pressed from one end side of the body portion 20 against the die 108 arranged on the outer periphery. This makes it possible to increase the pitch circle diameter of the gear to be formed.

[0010] Alternatively, in the above-described teeth forming step S302, it is preferable that the other end of the body portion 20 is supported by inserting a cylindrical member into the other end of the body portion 20.

[0011] When a cylindrical member is inserted into the other end of the body portion 20 to support the other end of the body portion 20, buckling caused by weak support at a particular point on the other end of the body portion 20 can be prevented. Effect of the Invention

[0012] According to the present invention, when a flange portion is provided on the other end of the cylindrical body, the possibility of cracks occurring during processing is reduced. [Brief description of the drawings]

[0013] [Figure 1] 1 is a flowchart showing each step of a method for forming a toothed cylinder according to a first embodiment of the present invention. [Diagram 2] 1 is a conceptual diagram showing a configuration of an other-end section step section forming device according to a first embodiment of the present invention. [Diagram 3] 1 is a conceptual diagram showing a configuration of a tooth forming device according to a first embodiment of the present invention. [Figure 4]4 is a conceptual diagram showing the other end section step section forming device performing the other end section forming step according to the first embodiment of the present invention. FIG. [Diagram 5] FIG. 1 is a conceptual diagram showing a teeth forming device performing a teeth forming step according to a first embodiment of the present invention. [Figure 6] FIG. 1 is a conceptual diagram showing the appearance of a toothed cylindrical body according to a first embodiment of the present invention. [Figure 7] 6 is a flowchart showing each step of a method for forming a toothed cylinder according to a second embodiment of the present invention. [Figure 8] 10 is a conceptual diagram showing a configuration of an other-end section step section forming device according to a second embodiment of the present invention. FIG. [Figure 9] FIG. 4 is a conceptual diagram showing the configuration of a tooth forming device according to a second embodiment of the present invention. [Figure 10] 13 is a conceptual diagram showing an other end section step section forming device performing an other end section forming step according to a second embodiment of the present invention. FIG. [Figure 11] FIG. 11 is a conceptual diagram showing a teeth forming device performing a teeth forming step according to a second embodiment of the present invention. [Figure 12] FIG. 11 is a conceptual diagram showing the appearance of a toothed cylindrical body according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are the same. Therefore, detailed descriptions thereof will not be repeated.

[0015] First Embodiment [Steps of forming a toothed cylinder] 1 is a flow chart showing each step of the method for forming a toothed cylinder according to the present embodiment. Each step of the method for forming a toothed cylinder according to the present embodiment will be described with reference to FIG.

[0016] The method for forming a toothed cylindrical body according to this embodiment includes a preform forming step S300 and a teeth forming step S302. In the preform forming step S300, a preform 12, which will be described later, is formed. In the teeth forming step S302, gear teeth 136, which will be described later, are formed by plastic processing. In this embodiment, the gear teeth 136 are formed on one end of the preform 12. Once the teeth 136 are formed, the preform 12 is extruded from a teeth forming die 108.

[0017] In this embodiment, the base material forming process S300 includes a material processing process S320, an other end section forming process S322, and a step forming process S324.

[0018] In the case of this embodiment, in the material processing step S320, a metal plate is subjected to plastic processing to form the tubular portion 40 having one end and the other end open, and the flange portion 22. The specific procedure is well known, so a detailed description thereof will not be repeated here.

[0019] In this embodiment, in the other end section forming step S322, the tubular portion 40 is subjected to plastic working so that the other end of the tubular portion 40 becomes thinner.

[0020] In this embodiment, in the step forming step S324, the diameter expanding roller 74 presses and smooths the portion of the base material 12 described below. The portion is a portion that will become one end of the partial section of the tubular portion 40 that was thinned in the other end section forming step S322. Thereafter, the base material pushing member 78 pushes out the base material 12 from the flange support member 70.

[0021] [Explanation of the configuration of the device used when carrying out the toothed cylinder forming method] 2 is a conceptual diagram showing the configuration of an other-end section step section forming device according to the present embodiment. The configuration of an apparatus used when performing the other-end section forming step S322 according to the present embodiment will be described with reference to FIG.

[0022] In this embodiment, the equipment used to carry out the other end section forming process S322 includes a flange support member 70, flange holding members 72, 72, expanding rollers 74, 74, an expanding roller holder 76, a base material extrusion member 78, an expanding roller holder rotation device (not shown), an up and down drive device (not shown), a flange holding drive device (not shown), and an extrusion drive device (not shown).

[0023] A cylindrical portion accommodating hole 90 is formed in the flange support member 70. The above-mentioned cylindrical portion 40 is accommodated in the cylindrical portion accommodating hole 90. An upper end surface 92 of the flange support member 70 supports the above-mentioned flange 22. The flange pressing member 72 presses the flange 22 against the upper end surface 92 of the flange support member 70. This causes the flange 22 to be fixed.

[0024] The diameter expanding roller 74 is disposed so as to be movable along the inner peripheral surface of the above-mentioned cylindrical portion 40. The diameter expanding roller 74 is rotatable about the central axis of the diameter expanding roller 74 itself. The diameter expanding roller 74 is a member for plastically deforming the above-mentioned cylindrical portion 40.

[0025] The diameter expansion roller holder 76 holds the diameter expansion roller 74 so that it can rotate about its own axis. The diameter expansion roller holder 76 moves when a force is applied. Accordingly, the diameter expansion roller 74 also moves. Furthermore, the diameter expansion roller holder 76 is rotatable about its own central axis.

[0026] The preform extrusion member 78 extrudes the preform 12 fitted in the cylindrical portion receiving hole 90 of the flange portion support member 70 from the hole.

[0027] The expanding roller holder rotating device drives the expanding roller holder 76 to rotate. The direction of rotation is the direction around the central axis of the expanding roller holder 76 itself. This rotation causes the expanding roller 74 to revolve.

[0028] The vertical drive device drives the expanding roller holder 76 to move in a linear direction. The moving direction is along the central axis of the expanding roller holder 76 itself.

[0029] The flange presser drive device drives the flange presser member 72 to press the flange 22 of the blank 12 against the upper end surface 92 of the flange support member 70 and release the pressing force.

[0030] The extrusion drive device drives the preform extruding member 78 which extrudes the preform 12 from the above-mentioned cylindrical portion receiving hole 90 formed in the flange portion support member 70 .

[0031] Fig. 3 is a conceptual diagram showing the configuration of a tooth forming apparatus according to this embodiment. The configuration of an apparatus used when performing the tooth forming step S302 according to this embodiment will be described with reference to Fig. 3.

[0032] In this embodiment, the tooth forming device includes a flange support member 100, flange holding members 102, 102, expanding rollers 104, 104, an expanding roller holder 106, a tooth forming die 108, a buckling prevention member 110, a raw material extrusion member 112, an expanding roller holder rotation device (not shown), a vertical drive device (not shown), a flange holding drive device (not shown), a buckling prevention member drive device (not shown), and an extrusion drive device (not shown).

[0033] The flange support member 100 supports the flange 22 of the preform 12. A body through hole 120 is formed in the flange support member 100. The body 20 of the preform 12 passes through the body through hole 120. In the present embodiment, when the body passes through, there is a gap between the inner peripheral surface of the body through hole 120 and the outer peripheral surface of the body 20. An upper end surface 122 of the flange support member 100 supports the flange 22 of the preform 12. The flange pressing member 102 presses the flange 22 of the preform 12 against the upper end surface 122 of the flange support member 100. This fixes the flange 22 of the preform 12.

[0034] The diameter expanding roller 104 is disposed so as to be movable along the inner circumferential surface of the body portion 20 of the preform 12. The diameter expanding roller 104 is rotatable about the central axis of the diameter expanding roller 104 itself. The diameter expanding roller 104 is a member for plastically deforming the body portion 20 of the preform 12.

[0035] The diameter expansion roller holder 106 holds the diameter expansion roller 104 so that it can rotate freely. When a force is applied, the diameter expansion roller holder 106 moves. Accordingly, the diameter expansion roller 104 also moves. Furthermore, the diameter expansion roller holder 106 is rotatable about the central axis of the diameter expansion roller holder 106 itself.

[0036] A teeth-forming section accommodating hole 126 is formed in the teeth-forming die 108. A teeth-forming section 130 (described later) of the body portion 20 of the preform 12 is accommodated in the teeth-forming section accommodating hole 126. The inner peripheral surface of the teeth-forming section accommodating hole 126 is formed with projections and recesses in the shape of gear teeth.

[0037] The buckling prevention member 110 is inserted into the other end of the body portion 20 of the preform 12. In this embodiment, the buckling prevention member 110 is a cylindrical member. The buckling prevention member 110 supports the body portion 20 so as to prevent buckling caused by processing of the preform 12 fitted in the teeth forming die 108 while the preform 12 is being processed.

[0038] The preformed material extruding member 112 extrudes the preformed material 12 fitted in the tooth-forming die 108 from the tooth-forming section accommodating hole 126 of the tooth-forming die 108. In the present embodiment, the above-mentioned diameter-expanding roller holder 106 penetrates a cylindrical space formed in the center of the preformed material extruding member 112.

[0039] The diameter expansion roller holder rotating device drives the diameter expansion roller holder 106 to rotate. The direction of rotation is the direction around the central axis of the diameter expansion roller holder 106 itself. This rotation causes the diameter expansion roller 104 to revolve.

[0040] The vertical drive device drives the diameter expansion roller holder 106 to move in a linear direction. The moving direction is along the central axis of the diameter expansion roller holder 106 itself.

[0041] The flange presser drive device drives the flange presser member 102 to press the flange 22 of the blank 12 against the upper end surface 122 of the flange support member 100 and release the pressing force.

[0042] The buckling prevention member driver drives the buckling prevention member 110 into and out of the other end of the body 20 .

[0043] The extrusion drive drives a blank extrusion member 112 that extrudes the blank 12 from the hole formed in the teeth forming die 108 .

[0044] [Description of the operations in each step when the toothed cylinder forming method is carried out] Fig. 4 is a conceptual diagram showing the other end section step section forming device performing the other end section forming step S322 according to this embodiment. Fig. 5 is a conceptual diagram showing the teeth forming device performing the teeth forming step S302 according to this embodiment. The specific contents of each step when the toothed cylindrical body forming method according to this embodiment is performed will be described with reference to Figs. 1 to 5.

[0045] A person who carries out the toothed cylinder forming method (hereinafter referred to as the "practitioner") applies plastic processing to a metal plate to form a tubular portion 40 with one end and the other end open, and a flange portion 22 (S320). In a later process, gear teeth 136 will be formed on one end of the tubular portion 40. The flange portion 22 is disposed on the outer edge of the other end of the tubular portion 40. In this embodiment, the flange portion 22 has an annular shape. The metal plate that has been subjected to this plastic processing becomes the article 10 according to this embodiment.

[0046] Next, the practitioner attaches the article 10 to the other-end section step section forming device. More specifically, the practitioner inserts the tubular section 40 of the article 10 into the tubular section accommodating hole 90 formed in the flange support member 70 of the other-end section step section forming device. As a result, the flange 22 of the article 10 is placed on the upper end surface 92 of the flange support member 70.

[0047] When the article 10 is attached to the other-end section step section forming device, the implementer controls the other-end section step section forming device so that the flange pressing member 72 presses the flange 22 of the article 10 against the upper end surface 92 of the flange support member 70. This presses the flange 22 of the article 10 against the upper end surface 92 of the flange support member 70. This pressing completes the fixing of the article 10.

[0048] When the fixation of the article 10 is completed, the practitioner controls a vertical drive device (not shown) so that the diameter expanding roller holder 76 and therefore the diameter expanding roller 74 approach the other end of the cylindrical portion 40 of the article 10. The left side of FIG. 4, bounded by the dashed dotted line, shows a state in which the diameter expanding roller 74 is approaching the other end of the cylindrical portion 40 of the article 10.

[0049] When the expanding roller holder 76 and thus the expanding roller 74 approach the other end of the cylindrical portion 40 of the article 10, the practitioner controls an expanding roller holder rotation device (not shown) to rotate the expanding roller holder 76. Furthermore, the practitioner controls a vertical drive device (not shown) to move the expanding roller holder 76 and thus the expanding roller 74 into the cylindrical portion 40 of the article 10. In response to these controls, the expanding roller 74 moves into the cylindrical portion 40.

[0050] When the diameter expanding roller 74 comes into contact with the inner peripheral surface of the tubular portion 40 as a result of the entry, the diameter expanding roller 74 receives a frictional force and starts to rotate. As the roller 74 rotates, the tubular portion 40 is pressed against the inner peripheral surface of the tubular portion accommodating hole 90 formed in the flange support member 70 by the diameter expanding roller 74. As a result, the thickness of the tubular portion 40 at the portion where the diameter expanding roller 74 comes into contact becomes thinner.

[0051] As the diameter expansion roller holder 76 continues to rotate and advances deeper into the cylindrical portion 40, the section of the cylindrical portion 40 with a thinner wall thickness gradually expands. After that, when the diameter expansion roller holder 76 advances to a predetermined position, the operator controls a vertical drive device (not shown) so that the diameter expansion roller holder 76 does not advance any further. As a result, a section with a thinner wall thickness is formed on the other end side of the cylindrical portion 40. In the case of this embodiment, the end at the other end where the thickness has decreased becomes the other end section 132. As a result, the other end section 132 is formed (S322) prior to the tooth forming step S302.

[0052] The expanding roller holder 76, which has not advanced any further, continues to rotate. As a result, the expanding roller 74 presses and smooths the portion of the cylindrical portion 40 described below. The portion is the end of the other end section 132 on the one end side of the cylindrical portion 40. The state in which the expanding roller 74 forms a step on the inner peripheral surface of the cylindrical portion 40 is shown on the right side of the dashed line in FIG. 4. When the step is formed, the implementer controls the vertical drive device (not shown) so that the expanding roller holder 76 and the expanding roller 74 are pulled out of the cylindrical portion 40. In the present embodiment, the portion pressed and smoothed in this manner becomes the step section 134. The portion of the cylindrical portion 40 on the one end side of the pressed and smoothed portion becomes the tooth forming section 130. In the present embodiment, when the pressing and smoothing is completed, the article 10 becomes the base material 12. The cylindrical portion 40 becomes the body portion 20.

[0053] When the expanding roller holder 76 and thus the expanding roller 74 are removed from the body portion 20 of the preform 12, the operator controls the extrusion drive device to drive the preform push-out member 78. Under this control, the preform push-out member 78 pushes out the preform 12 from the tubular portion accommodating hole 90 formed in the flange support member 70 (S324).

[0054] When the preform 12 is extruded from the other-end section step section forming device, the practitioner attaches the preform 12 to the teeth forming device. More specifically, the practitioner inserts the body 20 of the preform 12 into the body through-hole 120 formed in the flange support member 100 of the teeth forming device. As a result, the flange 22 of the preform 12 is placed on the upper end surface 122 of the flange support member 100. In addition, one end side of the body 20 enters the inside of the teeth forming section receiving hole 126 formed in the teeth forming die 108.

[0055] When the preform 12 is attached to the tooth forming apparatus, the practitioner controls the flange presser drive device so that the flange presser member 102 presses the flange 22 of the preform 12 against the upper end surface 122 of the flange support member 100. This causes the flange 22 of the preform 12 to be pressed against the upper end surface 122 of the flange support member 100. When the flange 22 of the preform 12 is pressed against the upper end surface 122 of the flange support member 100, the practitioner controls the buckling prevention member drive device so that the buckling prevention member 110 advances into the other end of the body 20. The advancement of the buckling prevention member 110 completes the fixing of the preform 12. As a result, at least the end of the other end section 132 on one end side of the body 20 is in a movable state and the flange 22 is in a fixed state. Furthermore, a cylindrical buckling prevention member 110 is inserted into the other end of the body portion 20, thereby supporting the body portion 20 so as to prevent buckling.

[0056] When the fixation of the preform 12 is completed, the practitioner controls a vertical drive device (not shown) so that the expanding roller holder 106 and thus the expanding roller 104 approach one end of the body portion 20 of the preform 12. The left side of Figure 5, bounded by the dashed dotted line, shows a state in which the expanding roller 104 is approaching one end of the body portion 20 of the preform 12.

[0057] When the expanding roller holder 106 and thus the expanding roller 104 approach one end of the body 20 of the preform 12, the practitioner controls an expanding roller holder rotation device (not shown) so as to rotate the expanding roller holder 106. Furthermore, the practitioner controls a vertical drive device (not shown) so as to move the expanding roller holder 106 and thus the expanding roller 104 into the interior of the body 20 of the preform 12. In accordance with these controls, the expanding roller 104 moves into the interior of the body 20.

[0058] When the expanding roller 104 comes into contact with the inner peripheral surface of the body portion 20 as a result of the entry, the expanding roller 104 receives a frictional force and starts to rotate on its axis. In parallel with this rotation, the tooth forming section 130 of the body portion 20 is pressed against the tooth forming section receiving hole 126 of the tooth forming die 108. As a result, one end side of the body portion 20 is deformed to fit the shape of the tooth forming section receiving hole 126 of the tooth forming die 108.

[0059] As the expanding roller holder 106 continues to rotate and advances toward the back of the body 20, the section of the body 20 pressed against the teeth forming die 108 gradually expands. As a result, the teeth forming section 130 of the body 20 is pressed against the teeth forming die 108. The right side of FIG. 5, bounded by the dashed line, shows a state in which the expanding roller 104 is pressing one end of the body 20 of the blank 12, and thus the teeth forming section 130, against the teeth forming section receiving hole 126 of the teeth forming die 108. After that, when the expanding roller holder 106 advances to the end on the one end side of the body 20, the practitioner controls the vertical drive device (not shown) so that the expanding roller 104 does not penetrate the body 20. As a result, the teeth forming die 108 forms gear teeth 136 in the teeth forming section 130 of the body 20.

[0060] When the gear teeth 136 are formed, the practitioner controls a vertical drive device (not shown) so that the expanding roller holder 106 and thus the expanding roller 104 are removed from the body portion 20 of the blank 12 .

[0061] When the expanding roller holder 106 and thus the expanding roller 104 are removed from the body 20 of the preform 12, the operator controls the extrusion drive device to drive the preform extrusion member 112. The preform extrusion member 112, under this control, extrudes the preform 12 from the teeth forming die 108 (S302). This completes the toothed cylindrical body 14 according to this embodiment. Figure 6 is a conceptual diagram showing the appearance of the toothed cylindrical body 14 according to this embodiment. Teeth 136 are formed in the area of ​​the preform 12 that was the tooth formation section 130.

[0062] [Effects of the method for forming a toothed cylinder according to this embodiment] According to the method for forming a toothed cylindrical body according to the present embodiment, when the teeth 136 are formed on the tooth forming section 130 in the tooth forming step S302, the tooth forming section 130 is pressed against the tooth forming die 108 arranged on the outer periphery. As the tooth forming section 130 is pressed against the tooth forming die 108 arranged on the outer periphery, stress is applied to each part of the base material 12. When the teeth 136 are formed on the tooth forming section 130 in the tooth forming step S302, at least the end of the other end section 132 on one end side of the body part 20 is in a movable state and the flange part 22 is in a fixed state. As a result, the stress applied to each part of the base material 12 is relaxed in the other end section 132 as the tooth forming section 130 is pressed against the tooth forming die 108 arranged on the outer periphery. Since the difference in stress applied to each part of the base material 12 is relaxed and the stress itself is relaxed, the possibility of cracks occurring during processing is reduced.

[0063] According to the method for forming a toothed cylinder of the present embodiment, the body 20 is supported so as to prevent buckling, and at least one end of the other end section 132 of the body 20 on one side is movable and the flange section 22 is fixed. As a result, at least one end of the other end section 132 of the body 20 on one side is displaced, and the difference in stress applied to each part of the preform 12 is alleviated. Moreover, the body 20 is supported so as to prevent buckling. Since the difference in stress is alleviated, it is possible to reduce the possibility that a particularly large stress is applied to any of the parts of the preform 12. Since such a possibility can be reduced, it is possible to reduce the possibility of cracks occurring during processing. Moreover, in this state, the tooth forming section 130 is pressed from one end side of the body 20 against the tooth forming die 108 arranged on the outer periphery. This makes it possible to increase the pitch circle diameter of the gear to be formed.

[0064] Furthermore, according to the method for forming a toothed cylinder of this embodiment, a cylindrical buckling prevention member 110 is inserted into the other end of the body portion 20 to support the other end of the body portion 20. This makes it possible to prevent buckling caused by weak support at a specific location on the other end of the body portion 20.

[0065] <Second embodiment> [Steps of forming a toothed cylinder] 7 is a flow chart showing each step of the toothed cylinder forming method according to this embodiment. Each step of the toothed cylinder forming method according to this embodiment will be described with reference to FIG.

[0066] The method for forming a toothed cylindrical body according to this embodiment includes a base material forming step S304 and a teeth forming step S306.

[0067] In the preform forming step S304, the preform 16 described below is formed. In the teeth forming step S306, gear teeth 138 described below are formed by plastic processing. In this embodiment, the gear teeth 138 are formed on one end of the preform 16. Once the teeth 138 are formed, the preform 16 is extruded from the teeth forming die 208.

[0068] In this embodiment, the base material forming step S304 includes a material processing step S320, an other end section forming step S342, and a step forming step S344.

[0069] In this embodiment, in the other end section forming step S342, the tubular portion 40 is subjected to plastic working so that the other end of the tubular portion 40 becomes thinner.

[0070] In this embodiment, in the step forming step S344, the diameter expanding roller 74 presses and smooths the portion of the base material 16 described below. The portion is a portion that will become one end of the partial section of the tubular portion 40 that was thinned in the other end section forming step S342. Thereafter, the base material pushing member 78 pushes out the base material 16 from the flange support member 170.

[0071] [Explanation of the configuration of the device used when carrying out the toothed cylinder forming method] 8 is a conceptual diagram showing the configuration of the other-end section step section forming device according to this embodiment, The configuration of the other-end section step section forming device according to this embodiment will be described with reference to FIG.

[0072] In this embodiment, the other end section step section forming device includes a flange support member 170, a flange holding member 72, an expanding roller 74, an expanding roller holder 176, a base material extrusion member 78, an expanding roller holder rotation device (not shown), an up and down drive device (not shown), a flange holding drive device (not shown), and an extrusion drive device (not shown).

[0073] The flange support member 170 supports the flange 22 of the article 10. A cylindrical portion accommodating hole 190 is formed in the flange support member 170. The cylindrical portion 40 of the article 10 is accommodated in the cylindrical portion accommodating hole 190. The cylindrical portion accommodating hole 190 has a different shape from the cylindrical portion accommodating hole 90 formed in the flange support member 70 according to the first embodiment. The inner diameter of the cylindrical portion accommodating hole 190 formed in the flange support member 170 is smaller at a portion facing one end side of the cylindrical portion 40, and is larger at a portion facing the other end side of the cylindrical portion 40. As a result, when the cylindrical portion 40 enters the cylindrical portion accommodating hole 190 formed in the flange support member 170, a gap is formed between the outer circumferential surface of the other end side and the inner circumferential surface of the cylindrical portion accommodating hole 190 formed in the flange support member 170. In this embodiment, the inner diameter of the cylindrical portion accommodating hole 190 formed in the flange support member 170 at a portion facing one end side of the cylindrical portion 40 is equal to the inner diameter of the cylindrical portion accommodating hole 90 formed in the flange support member 70 according to the first embodiment.

[0074] The diameter expansion roller holder 176 holds the diameter expansion roller 74 so that it can rotate about its own axis. The diameter expansion roller holder 176 moves when a force is applied. Accordingly, the diameter expansion roller 74 also moves. Furthermore, the diameter expansion roller holder 176 is rotatable about its own central axis. The difference between the diameter expansion roller holder 176 according to this embodiment and the diameter expansion roller holder 76 according to the first embodiment is the position at which the diameter expansion roller 74 is disposed. As a result, the radius of revolution of the diameter expansion roller 74 caused by the rotation of the diameter expansion roller holder 176 is larger than the radius of revolution of the diameter expansion roller 74 caused by the rotation of the diameter expansion roller holder 76 according to the first embodiment.

[0075] In other respects, the other-end section step section forming device according to this embodiment is similar to the other-end section step section forming device according to the first embodiment, and therefore detailed description thereof will not be repeated here.

[0076] Fig. 9 is a conceptual diagram showing the configuration of a tooth forming apparatus according to this embodiment. The configuration of an apparatus used when performing the tooth forming step S306 according to this embodiment will be described with reference to Fig. 9.

[0077] In this embodiment, the tooth forming device includes a flange support member 200, a flange holding member 102, 102, expanding rollers 204, 204, an expanding roller holder 206, a tooth forming die 208, a base material extrusion member 212, an expanding roller holder rotation device (not shown), a vertical drive device (not shown), a flange holding drive device (not shown), and an extrusion drive device (not shown).

[0078] The flange support member 200 supports the flange 22 of the preform 16. Like the flange support member 100 according to the first embodiment, the flange support member 200 is formed with a trunk through hole 420 through which the trunk 26 of the preform 16 passes with a gap. The trunk through hole 420 has a smaller inner diameter than the trunk through hole 120 formed in the flange support member 100 according to the first embodiment. As a result, the gap formed between the inner circumferential surface of the trunk through hole 420 formed in the flange support member 200 and the outer circumferential surface of the trunk 20 that enters therein is narrower than the gap in the first embodiment.

[0079] The diameter expanding roller 204 is disposed so as to be movable along the inner peripheral surface of the body 26 of the preform 16. The diameter expanding roller 204 is rotatable about its own central axis. The diameter expanding roller 204 is a member for plastically deforming the body 26 of the preform 16. The diameter expanding roller 204 according to this embodiment has a smaller outer diameter than the diameter expanding roller 104 according to the first embodiment. The diameter expanding roller 204 according to this embodiment is shorter than the diameter expanding roller 104 according to the first embodiment. In other words, the distance from one end to the other end in the central axis direction of the diameter expanding roller 204 itself is shorter. This is because the pitch circle of the teeth 138 formed on the body 26 of the diameter expanding roller 204 according to this embodiment is not as large as that of the diameter expanding roller 104 according to the first embodiment.

[0080] The diameter expansion roller holder 206 holds the diameter expansion roller 204 so that it can rotate freely. The diameter expansion roller holder 206 moves when a force is applied. Accordingly, the diameter expansion roller 204 also moves. The difference between the diameter expansion roller holder 206 according to this embodiment and the diameter expansion roller holder 106 according to the first embodiment is the position where the diameter expansion roller 204 is disposed. As a result, the radius of revolution of the diameter expansion roller 204 caused by the rotation of the diameter expansion roller holder 206 is smaller than the radius of revolution of the diameter expansion roller 104 caused by the rotation of the diameter expansion roller holder 106 according to the first embodiment.

[0081] The teeth forming die 208 is formed with a teeth forming section accommodating hole 426. The teeth forming section 230 of the body portion 26 of the preform 16 is accommodated in the teeth forming section accommodating hole 426. The inner peripheral surface of the teeth forming section accommodating hole 426 is formed with projections and recesses in the shape of gear teeth. The teeth forming die 208 forms gear teeth 138 on the outer periphery of the body portion 26 of the preform 16 by pressing the teeth forming section 230 against the projections and recesses.

[0082] The blank extrusion member 212 extrudes the blank 16 fitted in the tooth-forming die 208 from the tooth-forming section receiving hole 426 of the tooth-forming die 208 .

[0083] In other respects, the teeth forming device according to this embodiment is similar to the teeth forming device according to the first embodiment, and therefore detailed description thereof will not be repeated here.

[0084] [Description of the operations in each step when the toothed cylinder forming method is carried out] Fig. 10 is a conceptual diagram showing the other end section step section forming device performing the other end section forming step S342 according to this embodiment. Fig. 11 is a conceptual diagram showing the teeth forming device performing the teeth forming step S306 according to this embodiment. The specific contents of each step when the toothed cylindrical body forming method according to this embodiment is performed will be described with reference to Figs. 7 to 11.

[0085] The practitioner forms the article 10 by plastic processing of a metal material (S320). Once the article 10 is formed, the practitioner attaches the article 10 to the other-end section step section forming device. More specifically, the practitioner inserts the tubular portion 40 of the article 10 into the tubular portion accommodating hole 190 formed in the flange support member 170 of the other-end section step section forming device. As a result, the flange 22 of the article 10 is placed on the upper end surface 192 of the flange support member 170.

[0086] When the article 10 is attached to the other-end section step section forming device, the implementer controls a flange presser drive device (not shown) so that the flange presser member 72 presses the flange 22 of the article 10 against the upper end surface 192 of the flange support member 170. This presses the flange 22 of the article 10 against the upper end surface 192 of the flange support member 170. This pressing completes the fixation of the article 10.

[0087] When the fixation of the article 10 is completed, the practitioner controls a vertical drive device (not shown) so that the diameter expanding roller holder 176 and thus the diameter expanding roller 74 approach the other end of the cylindrical portion 40 of the article 10. The left side of FIG. 10, bounded by the dashed dotted line, shows a state in which the diameter expanding roller 74 is approaching the other end of the cylindrical portion 40 of the article 10.

[0088] When the expanding roller holder 176 and thus the expanding roller 74 approach the other end of the cylindrical portion 40 of the article 10, the practitioner controls an expanding roller holder rotation device (not shown) to rotate the expanding roller holder 176. Furthermore, the practitioner controls an up-down drive device (not shown) to move the expanding roller holder 176 and thus the expanding roller 74 into the cylindrical portion 40 of the article 10. In response to these controls, the expanding roller 74 moves into the cylindrical portion 40.

[0089] When the diameter expanding roller 74 comes into contact with the inner peripheral surface of the tubular portion 40 as a result of the entry, the diameter expanding roller 74 receives a frictional force and starts to rotate on its axis. As the roller 74 rotates, the tubular portion 40 is pressed against the inner peripheral surface of the tubular portion accommodating hole 190 formed in the flange support member 170 by the diameter expanding roller 74. As a result, the thickness of the tubular portion 40 at the portion where the diameter expanding roller 74 comes into contact becomes thinner. Furthermore, the inner diameter and outer diameter of the other end of the tubular portion 40 become larger.

[0090] As the diameter expansion roller holder 176 continues to rotate and advances deeper into the cylindrical portion 40, the section of the cylindrical portion 40 with a thinner wall thickness gradually expands. After that, when the diameter expansion roller holder 176 advances to a predetermined position, the operator controls a vertical drive device (not shown) so that the diameter expansion roller holder 176 does not advance any further. As a result, a section with a thinner wall thickness is formed on the other end side of the cylindrical portion 40. In the case of this embodiment, the end at the other end where the thickness has decreased becomes the other end section 232. As a result, the other end section 232 is formed (S342) prior to the tooth forming step S306.

[0091] The expanding roller holder 176, which has not advanced any further, continues to rotate. As a result, the expanding roller 74 presses and smooths the portion of the cylindrical portion 40 described below. The portion is the end of the other end section 232 on the one end side of the cylindrical portion 40. The state in which the expanding roller 74 forms a step on the inner peripheral surface of the cylindrical portion 40 is shown on the right side of the dashed line in FIG. 10. When the step is formed, the implementer controls the vertical drive device (not shown) so that the expanding roller holder 176 and the expanding roller 74 are pulled out of the cylindrical portion 40. In the present embodiment, the portion formed in this way becomes the step section 234. The portion of the cylindrical portion 40 on the one end side of the pressed and smoothed portion becomes the tooth forming section 230. In the present embodiment, when the pressing and smoothing is completed, the article 10 becomes the base material 16. The cylindrical portion 40 becomes the body portion 26.

[0092] When the expanding roller holder 176 and thus the expanding roller 74 are removed from the body portion 26 of the preform 16, the operator controls the extrusion drive device to drive the preform push-out member 78. Under this control, the preform push-out member 78 pushes out the preform 16 from the tubular portion accommodating hole 190 formed in the flange support member 170 (S324).

[0093] When the preform 16 is extruded from the other-end section step section forming device, the practitioner attaches the preform 16 to the teeth forming device. More specifically, the practitioner inserts the body 26 of the preform 16 into the body through-hole 420 formed in the flange support member 200 of the teeth forming device. As a result, the flange 22 of the preform 16 is placed on the upper end surface 422 of the flange support member 200. In addition, one end side of the body 26 enters the inside of the teeth forming section receiving hole 426 formed in the teeth forming die 208.

[0094] When the preform 16 is attached to the tooth forming apparatus, the operator controls the flange presser drive device so that the flange presser member 102 presses the flange 22 of the preform 16 against the upper end surface 422 of the flange support member 200. This causes the flange 22 of the preform 16 to be pressed against the upper end surface 422 of the flange support member 200. When the flange 22 of the preform 16 is pressed against the upper end surface 422 of the flange support member 200, the operator controls the vertical drive device (not shown) so that the expanding roller holder 206 and therefore the expanding roller 204 approach the other end of the body portion 26 of the preform 16. The left side of FIG. 11, bounded by the dashed and dotted line, shows a state in which the expanding roller 204 is approaching the other end of the body portion 26 of the preform 16.

[0095] When the expanding roller holder 206 and thus the expanding roller 204 approach the other end of the body 26 of the preform 16, the practitioner controls an expanding roller holder rotating device (not shown) so as to rotate the expanding roller holder 206. Furthermore, the practitioner controls a vertical drive device (not shown) so as to move the expanding roller holder 206 and thus the expanding roller 204 into the interior of the body 26 of the preform 16. In accordance with these controls, the expanding roller 204 moves into the interior of the body 26.

[0096] The expanding roller 204 that has entered the inside of the body portion 26 passes through the other end section 232 of the body portion 26 and comes into contact with the stepped section 234. When the expanding roller 104 comes into contact with the stepped section 234 of the body portion 26, the expanding roller 204 receives a frictional force and starts to rotate on its axis. In parallel with this rotation, the body portion 26 is pressed against the teeth forming section accommodating hole 426 of the teeth forming die 208. As a result, one end side of the body portion 26 is deformed to fit the shape of the teeth forming section accommodating hole 426 of the teeth forming die 208.

[0097] As the expanding roller holder 206 continues to rotate and advances to the back of the body 26, the section of the body 26 pressed against the tooth forming die 208 gradually expands. As a result, the tooth forming section 230 of the body 26 is pressed against the tooth forming die 208. The right side of FIG. 11, bounded by the dashed line, shows a state in which the expanding roller 204 is pressing one end of the body 26 of the blank 16, and thus the tooth forming section 230, against the tooth forming section receiving hole 426 of the tooth forming die 208. After that, when the expanding roller holder 206 advances to the end on the one end side of the body 26, the practitioner controls the vertical drive device (not shown) so that the expanding roller 204 does not penetrate the body 26. As a result, gear teeth 138 are formed in the tooth forming section 230 of the body 26.

[0098] When the gear teeth 138 are formed, the practitioner controls a vertical drive device (not shown) so that the expanding roller holder 206 and thus the expanding roller 204 are removed from the body portion 26 of the blank 16 .

[0099] When the expanding roller holder 206 and thus the expanding roller 204 are removed from the body 26 of the preform 16, the operator controls the extrusion drive device to drive the preform push-out member 212. The preform push-out member 212 controlled thereby pushes out the preform 16 from the teeth forming die 208 (S306). This completes the toothed cylindrical body 18 according to this embodiment. Figure 12 is a conceptual diagram showing the appearance of the toothed cylindrical body 18 according to this embodiment. Teeth 138 are formed in the portion of the preform 16 that was the tooth forming section 230.

[0100] [Effects of the method for forming a toothed cylinder according to this embodiment] According to the toothed cylindrical body forming method of this embodiment, when the teeth 138 are formed on the tooth forming section 230 in the tooth forming step S306, the tooth forming section 230 is pressed against the tooth forming die 208 arranged on the outer periphery. As the tooth forming section 230 is pressed against the tooth forming die 208 arranged on the outer periphery, stress is applied to each part of the preform 16. When the teeth 138 are formed on the tooth forming section 230 in the tooth forming step S306, at least the end of the body section 26 on one end side of the other end section 232 is in a movable state and the flange section 22 is in a fixed state. As a result, the stress applied to each part of the preform 16 is relaxed in the other end section 132 as the tooth forming section 230 is pressed against the tooth forming die 208 arranged on the outer periphery. Since the difference in stress applied to each part of the preform 16 is relaxed and the stress itself is relaxed, the possibility of cracks occurring during processing is reduced.

[0101] The embodiments disclosed herein are illustrative in all respects. The scope of the present invention is not limited to the above-described embodiments. Of course, various design changes may be made without departing from the spirit of the present invention. [Explanation of symbols]

[0102] 10...Goods 12,16…Materials 14, 18...Toothed cylinder 20,26…Torso 22…Flange 40…Cylindrical part 70, 100, 170, 200...Flange support member 72, 102...Flange holding member 74, 104, 204...Expanding roller 76, 106, 176, 206...Expansion roller holder 78, 112, 212…Extrusion parts 90, 190...Cylindrical portion receiving hole 92,122,192,422…Top end surface 108,208…Tooth forming mold 110...Buckling prevention member 120,420…Body through hole 126,426…Tooth formation section receiving hole 130,230…Tooth formation section 132,232...other end section 134,234…Step section 136,138…tooth

Claims

1. a blank forming step in which a blank having a cylindrical body portion is formed, The body portion is a teeth forming section which is a section disposed at one end; and an other end section disposed on the other end side of the tooth forming section, A method for forming a toothed cylindrical body, comprising, in addition to the base material forming step, a tooth forming step in which gear teeth are formed on the tooth forming section by plastic processing, the blank further includes a flange portion disposed on an outer edge of the other end of the body portion in addition to the body portion; The base material forming step includes: a material processing step in which a metal material is processed to form a cylindrical portion having one end and the other end open and the flange; and an other end section forming step of forming the other end section on the cylindrical portion prior to the teeth forming step, A method for forming a toothed cylindrical body, characterized in that in the tooth forming process, the teeth are formed on the tooth forming section by pressing the tooth forming section against a mold arranged on the outer periphery while at least the end of the other end section on one end side of the body portion is movable and the flange portion is fixed.

2. The method for forming a toothed cylindrical body as described in claim 1, characterized in that in the tooth forming process, the other end of the body portion is supported to prevent buckling, at least the end of the other end section on one end side of the body portion is in a movable state, and the flange portion is fixed, and the tooth forming section is pressed against a mold arranged on the outer periphery sequentially from one end side of the body portion, thereby forming the teeth on the tooth forming section.

3. 3. The method for forming a toothed cylindrical body according to claim 2, wherein in the teeth forming step, the other end of the body portion is supported by inserting a cylindrical member into the other end of the body portion.

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