JP2020066043A - Shaft thickening metal mold, shaft thickening device, stepped shaft manufacturing method and stepped shaft - Google Patents

Abstract

To provide a shaft thickening metal mold and a shaft thickening device which are suitably used for shaft thickening of a shaft material having a large diameter part and are excellent in durability, and to provide a manufacturing method for a stepped shaft having two large diameter parts, and a stepped shaft.SOLUTION: A shaft thickening metal mold 120 in a shaft thickening device 100 used for manufacture of a stepped shaft 1 comprises metal mold pieces 140 to 142 which are combined with each other thereby forming a ring form fitting to an outer periphery of a shaft material 2 and are divided in a circumferential direction of the ring form so as to be detachable in a radial direction with respect to the shaft material 2. The metal mold pieces 140 to 142 respectively have: a molding surface which is located on one end side in axial direction of the ring form, and molds an enlarged part 6 of the shaft material 2; an inner diameter surface located on an inner diameter side of the ring form; and a pair of abutting surfaces which abut against adjacent other metal mold pieces in the circumferential direction of the ring form. each corner part, which is formed by the molding surface, the inner diameter surface and the abutting surface, is chamfered.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a shaft enlargement processing die, a shaft enlargement processing apparatus, a stepped shaft manufacturing method, and a stepped shaft.

  Shaft enlargement (registered trademark) processing is known as one of the processing methods for forming a large diameter portion in a part of a shaft material. Shaft enlargement processing is typically performed by bending and rotating the shaft material while applying a compressive stress in the axial direction to the shaft material, thereby enlarging a part of the shaft material, thereby increasing the large diameter portion. To form.

  The chuck device described in Patent Document 1 is attached to at least one of a pair of spindles that rotate a shaft member in a shaft enlargement processing device, and is used to hold the shaft member. One of the chuck devices described in Patent Document 1 is a chuck body fixed to a spindle of a shaft enlargement processing apparatus, and a plurality of movable bodies arranged rotatably with respect to the chuck body in holes of the chuck body. And a sleeve. The plurality of movable sleeves are combined with each other in accordance with the rotation, and are separated from each other, and in the combined state, a holding hole for holding the shaft member is formed on the axis center of the chuck body and separated. In the state, it is separated from the axis of the chuck body.

  Another chuck device described in Patent Document 1 includes a chuck main body fixed to a spindle of a shaft enlargement processing device, and a plurality of sleeves detachably fitted into holes on an axial center of the chuck main body. The hollow portion of the main body and the plurality of sleeves are provided with tapered portions that are fitted to each other. The plurality of sleeves are combined with each other by being drawn into the holes of the chuck body and separated from each other by being removed from the chuck body. Formed on.

Japanese Patent No. 4594009

  In one chuck device described in Patent Document 1, a plurality of movable sleeves are rotated and separated from each other, so that a space larger than the holding hole is formed inside the plurality of movable sleeves. Therefore, the shaft material having a large diameter portion larger than the holding hole can be held by the chuck device. Also in the other chuck device described in Patent Document 1, a plurality of sleeves are fitted in the holes of the chuck body while holding the shaft member in advance, so that the shaft member has a large diameter portion larger than the holding hole. Can be held by a chuck device. In these cases, a stepped shaft having two large diameter portions, a large diameter portion formed in advance on the shaft material and an enlarged portion formed on the shaft material by shaft enlargement processing, can be obtained.

  However, the enlarged portion is formed by plastically flowing the material of the shaft material, and the plastic material of the shaft material that plastically flows has a gap between the abutting surfaces of the plurality of sleeves in the opening portion of the holding hole that is in close contact with the base portion of the enlarged portion. Enter. Further, a relatively large load acts on the opening of the holding hole, and this load repeatedly acts as the shaft member rotates. Therefore, the edges of the abutting surfaces of the plurality of sleeves may be damaged, such as cracked or chipped.

  The present invention has been made in view of the above circumstances, and is suitably used for shaft enlargement processing of a shaft material having a large diameter portion, and provides a shaft enlargement processing die and a shaft enlargement processing apparatus which are excellent in durability. An object of the present invention is to provide a method for manufacturing a stepped shaft having two large diameter portions and a stepped shaft.

  A mold for axial enlargement processing according to an aspect of the present invention is a shaft for partially enlarging the axial member by causing a compressive stress in the axial direction and a repeated shear stress in a direction intersecting the axial direction to act on the shaft member. A shaft enlargement processing mold used for enlargement processing, and by being combined with each other, an annular body that fits on the outer periphery of the shaft material is formed, and can be detachably attached to the shaft material in the radial direction. In, a plurality of mold pieces that are divided in the circumferential direction of the annular body is provided, the plurality of mold pieces are arranged on one end side in the axial direction of the annular body, and form an enlarged portion of the shaft member. Forming surface, an inner diameter surface arranged on the inner diameter side of the annular body, and a pair of abutting surfaces that are abutted with another mold piece adjacent in the circumferential direction of the annular body, respectively, the molding Each corner formed by the surface, the inner diameter surface, and the abutting surface, It is chamfered.

  Moreover, the shaft enlargement processing apparatus of one aspect of the present invention is a shaft enlargement for partially enlarging the shaft member by applying a compressive stress in the axial direction and a repeated shear stress in a direction intersecting the axial direction to the shaft member. In the processing device, the shaft enlargement processing device includes a pair of holders for holding both ends of the shaft member, and one first holder of the pair of holders is a first end part of the shaft member. For the shaft enlargement processing, a die mounting portion to which the shaft enlargement processing die fitted on the outer periphery is mounted, and an extrusion rod that comes into contact with the tip end portion of the first end portion of the shaft member. An accommodation space having a diameter larger than the inner diameter of the axial enlargement processing die is provided between the die and the extrusion rod.

  The method for manufacturing a stepped shaft according to an aspect of the present invention includes a large-diameter portion provided at the first end and a small-diameter shaft portion extending from the large-diameter portion to the second end. A pair of shaft enlargement processing dies are fitted to the outer periphery of the shaft portion of the shaft member, and an axial compression is applied to an intermediate portion of the shaft portion arranged between the pair of shaft enlargement processing dies. By applying a stress and a repeated shear stress in a direction intersecting the axial direction, the step of enlarging the intermediate portion of the shaft portion between the pair of shaft enlargement processing dies, and the shaft portion After enlarging the intermediate portion, the step of removing the shaft member from the pair of shaft enlargement working dies, one of which is arranged on the large diameter portion side of the pair of shaft enlargement processing dies. The shaft enlargement processing die is the shaft enlargement die, and the shaft enlargement processing die is divided into a plurality of die pieces. By, removing the shaft material from said shaft hypertrophic processing mold.

  Further, the stepped shaft according to one aspect of the present invention has a large-diameter portion provided at a first end portion of the shaft member and a gap between the large-diameter portion and the second end portion side of the shaft member. An enlarged portion provided with the large diameter portion and the enlarged portion, and a shaft portion having a diameter smaller than the large diameter portion and the enlarged portion, and the enlarged portion and the A plurality of protrusions are formed at intervals in the circumferential direction, or a plurality of protrusion removal marks are formed on the outer peripheral surface of the annular corner formed by the shaft portion.

  Advantageous Effects of Invention According to the present invention, a die for shaft enlargement processing and a shaft enlargement processing apparatus which are suitably used for shaft enlargement processing of a shaft material having a large diameter portion and have excellent durability are provided, and a step having two large diameter portions is provided. It is possible to provide a method of manufacturing the attached shaft and a stepped shaft.

It is a top view of an example of a stepped shaft for explaining the embodiment of the present invention. It is the II-II sectional view taken on the line of the stepped shaft of FIG. It is a top view of other examples of a stepped shaft for explaining the embodiment of the present invention. It is a schematic diagram which shows the application example of the stepped shaft of FIG. It is a schematic diagram of an example of a shaft enlargement processing apparatus for explaining the embodiment of the present invention. It is sectional drawing of the holder of the shaft enlargement processing apparatus of FIG. It is a perspective view of an example of a metal mold for axial enlargement for explaining the embodiment of the present invention. FIG. 5 is a schematic diagram showing a step of manufacturing a stepped shaft for explaining the embodiment of the present invention. FIG. 5 is a schematic diagram showing a step of manufacturing a stepped shaft for explaining the embodiment of the present invention. FIG. 5 is a schematic diagram showing a step of manufacturing a stepped shaft for explaining the embodiment of the present invention. FIG. 5 is a schematic diagram showing a step of manufacturing a stepped shaft for explaining the embodiment of the present invention. FIG. 5 is a schematic diagram showing a step of manufacturing a stepped shaft for explaining the embodiment of the present invention. FIG. 5 is a schematic diagram showing a step of manufacturing a stepped shaft for explaining the embodiment of the present invention. It is a perspective view of the metal mold | die for shaft axial expansion processing which expands and shows the part enclosed with the broken line frame IX of FIG. 8C. It is a schematic diagram of the other example of the shaft enlargement processing method for describing embodiment of this invention. It is a schematic diagram of the other example of the shaft enlargement processing method for describing embodiment of this invention. It is a schematic diagram of the other example of the shaft enlargement processing method for describing embodiment of this invention. It is a schematic diagram of the other example of the shaft enlargement processing method for describing embodiment of this invention.

  1 and 2 show an example of a stepped shaft for explaining an embodiment of the present invention.

  The stepped shaft 1 is provided with a large-diameter portion 4 provided at the first end portion 3 of the shaft material and a space on the second-end portion 5 side of the shaft material with respect to the large-diameter portion 4. The enlarged portion 6, the first shaft portion 7 provided between the large diameter portion 4 and the enlarged portion 6, and the second shaft portion 8 extending from the enlarged portion 6 to the second end portion 5 are provided. As the shaft member, for example, a round bar made of a metal material such as steel is used.

  The outer diameters of the first shaft portion 7 and the second shaft portion 8 are substantially the same as the outer diameter of the shaft material (material), and are smaller than the outer diameters of the large diameter portion 4 and the enlarged portion 6. The outer diameter of the large diameter portion 4 and the outer diameter of the enlarged portion 6 may be substantially the same, or one may be larger than the other. The large-diameter portion 4 is formed by, for example, forging processing, and the enlarged portion 6 is formed by axial enlargement processing. In the enlarged portion 6, a fiber flow of a metal structure resulting from the axial enlargement process is formed, and this fiber flow is typically in the cross section including the axis, the first shaft portion 7 and the second shaft portion. 8 toward the enlarged portion 6 and from the axial center side toward the outer diameter side of the enlarged portion 6.

  On the outer peripheral surface of the annular corner portion 9 formed by the enlarged portion 6 and the first shaft portion 7, a plurality of projections 10 are provided at intervals in the circumferential direction, and the example shown in FIGS. In, three protrusions 10 are provided at equal intervals in the circumferential direction. The protrusion 10 is formed along with the shaft enlargement process for forming the enlarged portion 6, and is integral with the enlarged portion 6 and the first shaft portion 7. The protrusion 10 is, for example, a burr, or a rib that reinforces the enlarged portion 6. The number and arrangement of the protrusions 10 differ depending on the axial enlargement processing die used for axial enlargement processing, but the intersection angle φ of two straight lines connecting the two axially adjacent protrusions 10 and the axis is 180. ° or less. When the protrusion 10 is a burr, the protrusion 10 may be removed by cutting or the like, and when the protrusion 10 is removed, a protrusion removal mark is formed on the outer peripheral surface of the corner 9.

  FIG. 3 shows a modification of the stepped shaft 1.

  In the stepped shaft 11 shown in FIG. 3, the second shaft portion 8 of the stepped shaft 1 is cut off, and the end surface 6a of the enlarged portion 6 formed by cutting off the second shaft portion 8 has another shaft member. 12 is coaxially joined. The outer diameter of the joint end portion 13 of the shaft member 12 and the outer diameter of the enlarged portion 6 are substantially the same. Since the enlarged portion 6 has a larger diameter than the excised second shaft portion 8, it is larger than joining the second shaft portion 8 and a shaft material having an outer diameter substantially the same as that of the second shaft portion 8. By joining the portion 6 and the shaft member 12 having an outer diameter substantially the same as that of the enlarged portion 6, the joining area can be increased and the joining strength can be increased. Examples of the method of joining the enlarged portion 6 and the shaft member 12 include friction welding and ultrasonic welding.

  The material of the shaft member 12 and the material of the shaft member used in the stepped shaft 1 may be the same or different. For example, the material of the shaft material used for the stepped shaft 1 may be special steel having excellent mechanical strength, hardness, corrosion resistance, heat resistance, etc., and the material of the shaft material 12 may be ordinary steel. The stepped shaft 11 can be suitably used for the drive shaft DS of the outboard motor, for example. In the drive shaft DS shown in FIG. 4, the tip end side connected to the prober shaft PS and at least the part that is submerged in water is formed by the stepped shaft 1 made of special steel, and the large size of the stepped shaft 1 A bevel gear for transmitting rotation to the prober shaft is formed on the diameter portion 4. On the other hand, the base end side connected to the engine E and the part arranged above the water surface WS is formed by the shaft member 12 made of ordinary steel. This makes it possible to satisfy the corrosion resistance required for the drive shaft DS and reduce the manufacturing cost of the drive shaft DS. The shaft material 12 may be a round bar or a hollow circular tube. When the shaft member 12 is a circular pipe, it is possible to reduce the weight of the stepped shaft 11.

  FIG. 5 shows an example of a shaft enlargement processing apparatus for explaining the embodiment of the present invention.

  The shaft enlargement processing is to partially enlarge the shaft material by causing compressive stress in the axial direction and repeated shear stress in a direction intersecting the axial direction to act on the shaft material, and the shaft enlargement processing shown in FIG. The device 100 repeatedly applies shear stress to the shaft member by rotating the shaft member while bending the shaft member. The shaft material 2 processed by the shaft enlargement processing apparatus 100 is a shaft material used for manufacturing the stepped shaft 1 described above, and includes the large diameter portion 4 provided at the first end portion 3 and the large diameter portion. 4 and a shaft portion 14 extending from the second end portion 5 to the second end portion 5. The outer diameter of the shaft portion 14 is smaller than the outer diameter of the large diameter portion 4.

  The shaft enlargement processing device 100 includes a pair of holders 101 and 102 that are arranged apart from each other on a reference line C on which the shaft member 2 is arranged. The holder 101 holds the second end 5 of the shaft member 2 and is supported by the base 103 so as to be movable along the reference line C. The holder 102 holds the first end 3 of the shaft member 2 and is supported by the base 103 so as to be tiltable with respect to the reference line C.

  The holder 101 that holds the second end portion 5 of the shaft member 2 is provided with an annular shaft enlargement processing mold 110 that fits around the outer periphery of the shaft portion 14 of the shaft member 2 and a shaft enlargement processing mold 110. A spindle 111, a housing 112 that rotatably supports the spindle 111, and an extrusion rod 113. The push rod 113 is in contact with the tip of the second end 5 of the shaft member 2, and is driven by a linear motion device 114 such as a cylinder to press the second end 5 in the axial direction. The holder 102 also has a shaft enlargement processing die, a spindle, a housing, an extrusion rod, and a linear motion device.

  Then, the shaft enlargement processing apparatus 100 includes a pressing unit 104 that moves the holder 101 along the reference line C, a tilting unit 105 that tilts the holder 102 with respect to the reference line C, and a rotation that rotates the spindle of the holder 102. And a unit 106. When both ends 3 and 5 of the shaft member 2 are held by the pair of holders 101 and 102, the holder 101 is moved to the holder 102 side along the reference line C, whereby compressive stress is applied to the shaft member 2. To work. Further, by tilting the holder 102 with respect to the reference line C, the intermediate portion of the shaft portion 14 arranged between the pair of holders 101 and 102 is bent. The shaft 2 is rotated by rotating the spindle of the holder 102. The spindle 111 of the holder 101 is rotated integrally with the shaft member 2.

  FIG. 6 shows the structure of the holder 102 that holds the first end 3 of the shaft member 2.

  The holder 102 that holds the first end portion 3 of the shaft member 2 is mounted with an annular shaft enlargement processing mold 120 that fits around the shaft portion 14 of the shaft member 2 and a shaft enlargement processing mold 120. It has a spindle 121 and an extruding rod 123. In FIG. 5, the housing that rotatably supports the spindle 121 and the linear motion device that drives the push rod 123 are omitted.

  The spindle 121 has a mold mounting portion 125 to which the shaft enlargement processing die 120 is mounted. The mold mounting portion 125 includes the first end portion 3 of the shaft member 2 and the shaft enlargement processing die 120. Has a housing hole 126 for housing The push rod 123 penetrates the spindle 121 in the axial direction and projects from the bottom of the accommodation hole 126 into the accommodation hole 126. An accommodation space 127 having a diameter larger than the inner diameter of the axial enlargement mold 120 is provided between the axial enlargement mold 120 and the extrusion rod 123 accommodated in the accommodation hole 126. In the accommodation space 127, the large diameter portion 4 of the shaft member 2 protruding from the shaft enlargement processing die 120 toward the bottom of the accommodation hole 126 is arranged.

  The push rod 123 is in contact with the distal end portion of the first end portion 3 of the shaft member 2, that is, the large-diameter portion 4 of the shaft member 2 arranged in the housing space 127. Axial compressive stress is applied to the shaft member 2 sandwiched between the push rod 113 (see FIG. 5) of the holder 101 and the push rod 123 of the holder 102 according to the movement of the holder 101. Then, the inclination of the holder 102 and the inclination of the holder 102 are provided at the intermediate portion of the shaft portion 14 arranged between the axial enlargement processing die 110 (see FIG. 5) of the holder 101 and the axial enlargement die 120 of the holder 102. Shear stress in a direction intersecting the axial direction repeatedly acts according to the rotation of the spindle 121. As a result, the intermediate portion of the shaft portion 14 is enlarged between the shaft enlargement processing die 110 and the shaft enlargement processing die 120, and the enlarged portion 6 is formed.

  The holder 102 further includes an annular sleeve 130, an annular washer 131, and a holding ring 132. The sleeve 130 is detachably fitted to the outer circumference of the shaft enlargement processing die 120 and fitted to the inner circumference of the accommodation hole 126. The washer 131 is sandwiched between the sleeve 130, the shaft enlargement processing die 120, and the bottom of the accommodation hole 126, and surrounds the outer periphery of the accommodation space 127. The pressing ring 132 is fixed to the opening 134 of the mold mounting portion 125 with the flange portion 133 of the sleeve 130 sandwiched between the pressing ring 132 and the washer 131.

  The sleeve 130 sandwiched between the pressing ring 132 and the washer 131 is fixed to the mold mounting portion 125 while being fitted to the inner circumference of the accommodation hole 126. On the other hand, the shaft enlargement processing die 120 that is detachably fitted to the inner periphery of the sleeve 130 is also attachable to and detachable from the die mounting portion 125, and by abutting against the washer 131, the shaft inside the accommodation hole 126. The position of the direction is fixed. When the large-diameter portion 4 of the shaft member 2 is pressed by the extruding rod 123, the shaft enlargement processing die 120 is extruded from the housing hole 126 integrally with the first end 3 of the shaft member 2.

  Preferably, as shown in FIG. 6, a spacer 135 is provided between the axial enlargement processing die 120 and the extrusion rod 123, and the axial enlargement processing die 120 is also pressed by the extrusion rod 123. As a result, relative movement between the shaft member 2 and the shaft enlargement processing die 120 is suppressed, and for example, it is possible to prevent the outer peripheral surface of the shaft portion 14 from being scratched.

  In addition, preferably, the sleeve 130 has one or more convex portions 136 protruding on the inner peripheral surface of the sleeve 130, and the outer periphery of the shaft enlargement working die 120 detachably fitted to the inner periphery of the sleeve 130. The surface is provided with a recess 137 that circumferentially engages with the projection 136. In the example shown in FIG. 6, the spring plunger 138 is embedded in the sleeve 130, and the tip end portion of the spring plunger 138 constitutes the convex portion 136. By the engagement of the convex portion 136 and the concave portion 137, the rotation of the shaft enlargement processing die 120 with respect to the sleeve 130 is blocked, and the rotation of the spindle 121 is prevented from rotating via the sleeve 130 and the shaft enlargement processing die 120. It is reliably transmitted to the material 2. The protrusion 136 may be formed by a key joined to the sleeve 130, and in this case, the recess 137 is formed by a key groove extending in the axial direction from one end of the shaft enlargement working die 120.

  FIG. 7 shows the structure of the shaft enlargement processing die 120.

  The shaft enlargement processing die 120 includes a plurality of die pieces, and in the example illustrated in FIG. 7, includes three die pieces 140 to 142. By combining the mold pieces 140 to 142 with each other, an annular shaft enlargement processing mold 120 that fits on the outer periphery of the shaft portion 14 of the shaft member 2 is formed. The mold pieces 140 to 142 are divided in the circumferential direction of the annular shaft enlargement processing mold 120, and each has a substantially fan-shaped cross section, and its central angle φ is 180 ° or less. Since the central angle φ of each of the mold pieces 140 to 142 is 180 ° or less, the mold pieces 140 to 142 can be attached to and detached from the shaft portion 14 of the shaft member 2 in the radial direction.

  As long as the central angle φ is 180 ° or less, the number of mold pieces forming the axial enlargement processing mold 120 and the central angle φ of each mold piece are not particularly limited. The axial enlargement processing die 120 may be formed by, for example, two die pieces having a central angle φ of 180 °. However, preferably, the axial enlargement working die 120 is formed by three or more die pieces having a central angle φ of less than 180 °. As a result, each mold piece can be smoothly attached to and detached from the shaft portion 14 of the shaft member 2 regardless of some molding error. More preferably, the axial enlargement working die 120 is formed by three die pieces 140 to 142 having a central angle φ of 120 ° as shown in FIG. 7. This makes it easy to manufacture the mold pieces and also to combine the mold pieces.

  The mold piece 140 includes a substantially fan-shaped molding surface 140a arranged on one end side in the axial direction of the shaft enlargement processing mold 120, and an inner diameter surface 140b arranged on the inner diameter side of the shaft enlargement processing mold 120. It has a pair of abutting surfaces 140c and 140d that are abutted with the other die pieces 141 and 142 that are adjacent to each other in the circumferential direction of the axial enlargement die 120. The mold piece 141 and the mold piece 142 also have a molding surface, an inner diameter surface, and a pair of abutting surfaces, respectively. The molding surface of each of the mold pieces 140 to 142 is in contact with the enlarged portion 6 of the shaft member 2 in the shaft enlargement processing die 120 and forms a molding surface 128 (see FIG. 6) for forming the enlarged portion 6.

  8A to 8F show a manufacturing process of the stepped shaft 1 using the shaft enlargement processing apparatus 100.

  The shaft member 2 used for manufacturing the stepped shaft 1 has a large diameter portion 4 provided at the first end portion 3 and a shaft portion 14 extending from the large diameter portion 4 to the second end portion 5. First, as shown in FIG. 8A, the die 120 for shaft enlargement processing in which the die pieces 140 to 142 are attached in the radial direction with respect to the shaft material 2 and the die pieces 140 to 142 are combined is a shaft material. It is fitted to the outer circumference of the second shaft portion 14.

  Next, as shown in FIG. 8B, the first end portion 3 of the shaft member 2 and the shaft enlargement processing die 120 are housed in the housing hole 126 of the spindle 121 of the holder 102. The large-diameter portion 4 of the shaft member 2 is arranged in a housing space 127 provided between the pushing rod 123 of the holder 102 and the shaft enlargement processing die 120. Then, the holder 101 is moved to the holder 102 side along the reference line C, and the shaft portion 14 of the shaft member 2 is relatively inserted from the second end 5 side into the shaft enlargement processing die 110 of the holder 101. To be done. A space D is provided between the shaft enlargement processing die 110 and the shaft enlargement processing die 120, which are fitted to the outer periphery of the shaft portion 14. The distance D is appropriately set according to the axial length and the outer diameter of the enlarged portion 6 formed on the shaft portion 14.

  Next, as shown in FIG. 8C, the holder 101 is moved to the holder 102 side along the reference line C, and an axial compressive stress is applied to the shaft member 2. Further, when the holder 102 is tilted with respect to the reference line C, the intermediate portion of the shaft portion 14 arranged between the axial enlargement processing die 110 and the axial enlargement processing die 120 is bent. The bending angle θ is typically 2 ° to 4 °. Then, the shaft 121 is rotated by rotating the spindle 121 of the holder 102.

  As shown in FIG. 8D, with the rotation of the shaft member 2, a shear stress in a direction intersecting the axial direction is repeatedly applied to the intermediate portion of the shaft portion 14 based on the compression on the bending inner side and the tension on the bending outer side. . Since the compressive stress in the axial direction also acts on the intermediate portion of the shaft portion 14, the material on the inner side of the bend in the intermediate portion of the shaft portion 14 plastically flows toward the outer diameter side and swells. The bulge grows over the entire circumference to form the enlarged portion 6.

  As shown in FIG. 8E, after the interval between the shaft enlargement processing die 110 and the shaft enlargement processing die 120 reaches a predetermined interval (a predetermined axial length of the enlarged part 6), the shaft material 2 is compressed. Be stopped. Then, the holder 102 tilted with respect to the reference line C is again arranged on the reference line C, and the shaft portion 14 is bent back. From the above, the stepped shaft 1 is obtained.

  Thereafter, as shown in FIG. 8F, the rotation of the stepped shaft 1 is stopped, and the stepped shaft 1 is removed from the shaft enlargement processing dies 110, 120. The holder 101 is moved to the side opposite to the holder 102 side along the reference line C, and the second end portion 5 of the stepped shaft 1 is pressed by the pushing rod 113 of the holder 101, and the stepped shaft 1 of the holder 101 is moved. It is extruded from the shaft enlargement processing die 110. Further, the large-diameter portion 4 of the stepped shaft 1 is pressed by the pushing rod 123 of the holder 102, and the first end 3 of the stepped shaft 1 and the shaft enlargement processing die 120 are attached to the spindle 121 of the holder 102. It is pushed out integrally from the accommodation hole 126. The stepped shaft 1 is removed from the mold pieces 140 to 142 by separating the shaft enlargement processing mold 120 pushed out from the accommodation hole 126 into the mold pieces 140 to 142.

  Here, in the step of forming the enlarged portion 6 shown in FIGS. 8C to 8D, the opening 129 on the molding surface 128 side of the axial enlargement processing die 120 is in close contact with the base portion of the enlarged portion 6, The material of the shaft material 2 that plastically flows is between the adjacent mold piece 140 and the mold piece 141, between the mold piece 141 and the mold piece 142, and between the mold piece 142 and the mold piece 140. The space enters the gap exposed in the opening 129. Then, the material of the shaft member 2 that has entered these gaps forms a protrusion 10 (see FIGS. 1 and 2) on the outer peripheral surface of the annular corner portion 9 of the manufactured stepped shaft 1. The gaps are provided at three positions of the opening 129 at equal intervals in the circumferential direction, and the protrusions 10 are also provided at three positions of the annular corner portion 9 at equal intervals in the circumferential direction.

  FIG. 9 is an enlarged view showing a gap into which the material of the shaft member 2 enters.

  FIG. 9 shows a gap 143 provided between the mold piece 140 and the mold piece 141 in the opening 129 of the axial enlargement processing mold 120. The gap 143 is provided between a corner 140e of the mold piece 140 arranged in the opening 129 and a corner 141e of the mold piece 141. The corner portion 140e is formed by the molding surface 140a of the mold piece 140, the inner diameter surface 140b, and one butting surface 140c, and the corner portion 141e is formed by the molding surface 141a of the mold piece 141 and the inner diameter surface 141b. And one abutting surface 141d, and both corners 140e and 141e are chamfered.

  When the material of the shaft member 2 enters the gap 143, the both corners 140e and 141e receive a load according to the compressive stress and the repeated shear stress acting on the shaft member 2. By chamfering both corners 140e and 141e, stress concentration in both corners 140e and 141e is relaxed, and damage such as cracks and chips is suppressed from occurring in both corners 140e and 141e. Although not shown, the other corners of the mold pieces 140 to 142 arranged in the opening 129 are also chamfered in the same manner, and it is possible to prevent damage such as cracks and chips from occurring in each corner. As a result, the durability of the shaft enlargement processing die 120 can be improved, and the life of the shaft enlargement processing die 120 can be extended. Chamfering of each corner of the mold pieces 140 to 142 may be C chamfering, but is preferably R chamfering, and stress concentration at each corner can be further alleviated.

  In the shaft enlargement processing device 100 described above, the shaft enlargement processing die 120 including the die pieces 140 to 142 is integrally attached to and detached from the spindle 121 of the holder 102 with the shaft member 2. Like the chuck device described in (1), the mold pieces 140 to 142 may be disposed inside the accommodation hole 126 of the spindle 121 so as to be rotatable with respect to the spindle 121 of the holder 102. In this case, the mold pieces 140 to 142 are combined with each other and separated from each other according to the rotation. The large diameter portion 4 of the shaft member 2 is passed through the inside of the mold pieces 140 to 142 separated from each other. However, the movable range of the mold pieces 140 to 142 is limited to the inside of the housing hole 126, and the outer diameter of the large diameter portion 4 of the shaft member 2 which is passed through the inside of the mold pieces 140 to 142 is also limited. In this respect, the shaft enlargement processing die 120 including the die pieces 140 to 142 is integrally attached to and detached from the spindle 121 of the holder 102 with the shaft member 2 so that the movable range of the die pieces 140 to 142 is reduced. There is no limit, and it is possible to deal with a larger large diameter portion 4.

  Further, the shaft enlargement processing apparatus 100 bends the shaft portion 14 of the shaft material 2 by tilting the holder 102 that holds the first end portion 3 of the shaft material 2 with respect to the reference line C, and bends the shaft portion 14. Although the shearing stress is repeatedly applied to the shaft portion 14 by rotating the shaft member 2 with, the shearing stress may be repeatedly applied to the shaft portion 14 by another method.

  The example shown in FIG. 10 is common to the shaft enlargement processing method described above in that shearing stress is repeatedly applied to the shaft portion 14 of the shaft material 2 by bending and rotation, but a holder for holding the first end portion 3 of the shaft material 2 Instead of tilting A with respect to the reference line C, the holder A is slid in a direction intersecting with the reference line C to bend the shaft portion 14.

  In the example shown in FIG. 11, the holder B holds the second end 5 of the shaft member 2 in a non-rotatable restraint state, and the holder A holds the first end portion 3 of the shaft member 2 in an unconstrained state. By rotating the holder A around the reference line C, shear stress is repeatedly applied to the shaft portion 14 of the shaft member 2.

  In addition, in the example shown in FIG. 12, both ends 3 and 5 of the shaft member 2 are held in a non-rotatable restraint state by the holders A and B, and the holder A is reciprocally rotated around the reference line C, whereby the shaft member 2 is rotated. Shear stress is repeatedly applied to the shaft portion 14 of.

  In addition, in the example shown in FIG. 13, a shearing stress is repeatedly applied to the shaft portion 14 of the shaft member 2 by applying bending or torsional vibration to the shaft member 2 from the vibration generator OSC.

  As described above, the mold for axial enlargement processing disclosed in the present specification is such that the axial stress is exerted on the axial stress by applying compressive stress in the axial direction and repeated shear stress in the direction intersecting with the axial direction. Is a metal mold for shaft enlargement processing used for shaft enlargement processing for partially enlarging, forming an annular body fitted to the outer periphery of the shaft material by combining with each other, and a diameter with respect to the shaft material. So as to be attachable / detachable in a direction, a plurality of mold pieces that are divided in the circumferential direction of the annular body are provided, and the plurality of mold pieces are arranged at one end side in the axial direction of the annular body, A molding surface for molding the enlarged portion of the shaft member, an inner diameter surface arranged on the inner diameter side of the annular body, and a pair of abutting surfaces that are abutted with another die piece adjacent in the circumferential direction of the annular body, Respectively, the molding surface, the inner diameter surface, and the abutting surface Thus the corners formed is chamfered.

  Further, in the shaft enlargement processing die disclosed in the present specification, the corners are rounded.

  Further, the die for shaft enlargement processing disclosed in this specification is attached to and detached from the shaft enlargement processing apparatus integrally with the shaft material.

  Further, the shaft enlargement processing device disclosed in the present specification is a shaft for partially enlarging the shaft member by applying compressive stress in the axial direction and repeated shear stress in a direction intersecting the axial direction to the shaft member. An enlargement processing apparatus, wherein the shaft enlargement processing apparatus includes a pair of holders for holding both end portions of the shaft member, and one first holder of the pair of holders is a first end portion of the shaft member. A mold mounting part to which the shaft enlargement processing mold according to any one of claims 1 to 3 fitted on the outer periphery of the shaft, and a tip part of the first end part of the shaft member are contacted. An extrusion rod is provided, and a housing space having a diameter larger than the inner diameter of the axial enlargement die is provided between the axial enlargement die and the extrusion rod.

  Further, in the shaft enlargement processing device disclosed in the present specification, the mold mounting portion has a storage hole that stores the first end portion of the shaft member and the shaft enlargement processing mold, The shaft enlargement processing die is extruded from the accommodation hole integrally with the shaft member by the extrusion rod.

  Further, in the shaft enlargement processing device disclosed in the present specification, the first holder is an annular shape that is detachably fitted to the outer periphery of the shaft enlargement processing die and is fitted to the inner periphery of the accommodation hole. A sleeve and an outer circumference of the accommodation space, and an annular washer sandwiched between the sleeve and the shaft enlargement processing die and the bottom of the accommodation hole, and the sleeve is sandwiched between the washer, A pressing ring fixed to the mold mounting portion.

  Further, in the shaft enlargement processing device disclosed in the present specification, the sleeve has one or more protrusions protruding from the inner peripheral surface of the sleeve, and the outer peripheral surface of the shaft enlargement processing die is A concave portion is provided which engages with the convex portion in the circumferential direction.

  Further, in the shaft enlargement processing device disclosed in the present specification, the first holder has a spacer sandwiched between the shaft enlargement processing die and the extrusion rod.

  Further, the method for manufacturing a stepped shaft disclosed in the present specification includes a large diameter portion provided at the first end portion and a small diameter shaft portion extending from the large diameter portion to the second end portion. A pair of shaft enlargement processing dies are fitted to the outer periphery of the shaft portion of the shaft member, and an axial direction is provided in an intermediate portion of the shaft portion arranged between the pair of shaft enlargement processing dies. A step of enlarging the intermediate portion of the shaft portion between the pair of shaft enlargement processing dies by applying a compressive stress and a repeated shear stress in a direction intersecting the axial direction, and a step of the shaft portion. Removing the shaft member from the pair of shaft enlargement working dies after enlarging the intermediate portion, and is arranged on the large diameter portion side of the pair of shaft enlargement working dies. One of the shaft enlargement processing dies is the shaft enlargement processing die, and the shaft enlargement processing die is a plurality of mold pieces. By separating, removing the shaft material from said shaft hypertrophic processing mold.

  In the method for manufacturing a stepped shaft disclosed in the present specification, a step of cutting a portion of the shaft portion extending from the enlarged portion formed by enlarging the intermediate portion toward the second end portion side is cut off. And a step of joining another shaft member to the enlarged portion.

  Further, the stepped shaft disclosed in the present specification has a large-diameter portion provided at the first end portion of the shaft member and a gap on the second end portion side of the shaft member with respect to the large-diameter portion. An enlarged portion provided separately, and provided between the large diameter portion and the enlarged portion, a shaft portion having a diameter smaller than the large diameter portion and the enlarged portion, and the enlarged portion. On the outer peripheral surface of the annular corner formed by the shaft portion, a plurality of protrusions are formed at intervals in the circumferential direction, or a plurality of protrusion removal marks are formed.

  In the stepped shaft disclosed in the present specification, another shaft member is joined to the enlarged portion.

1 Stepped Shaft 2 Shaft 3 First End 4 Large Diameter 5 Second End 6 Enlarged Part 7 First Shaft 8 Second Shaft 9 Corner 10 Burr 11 Step Shaft 12 Shaft 13 Joint End 14 Shaft 100 Shaft Enlargement Processing Device 101 Holder 102 Holder 103 Base 104 Pressing Unit 105 Tilt Part 106 Rotating Part 110 Shaft Enlargement Mold 111 Spindle 112 Housing 113 Extrusion Rod 114 Linear Actuator 120 Shaft Enlargement Processing Gold Mold 121 Spindle 123 Extrusion rod 125 Mold mounting portion 126 Storage hole 127 Storage space 128 Molding surface 129 Opening 130 Sleeve 131 Washer 132 Pressing ring 133 Flange 134 Opening 135 Spacer 136 Convex 137 Recess 138 Spring plunger 140 Mold piece 140a Molding surface 140b Inner diameter surface 140c Butt surface 140d Butt surface 140e Corner 141 mold piece 142 mold piece 143 gap

Claims (12)

A shaft enlargement working die used for shaft enlargement processing for partially enlarging the shaft material by causing a compressive stress in the axial direction and a repeated shear stress in a direction intersecting the axial direction to act on the shaft material. ,
By combining with each other, a plurality of annular bodies that are fitted to the outer circumference of the shaft member are formed, and a plurality of members are divided in the circumferential direction of the annular member so that they can be attached to and detached from the shaft member in the radial direction. Equipped with mold pieces,
The plurality of mold pieces,
A molding surface that is disposed on one end side in the axial direction of the annular body and that molds the enlarged portion of the shaft member,
An inner diameter surface arranged on the inner diameter side of the annular body,
A pair of abutting surfaces that are abutted with another mold piece adjacent in the circumferential direction of the annular body,
Respectively,
Each of the corners formed by the molding surface, the inner diameter surface, and the abutting surface is chamfered, which is a mold for axial enlargement processing. The mold for shaft enlargement processing according to claim 1,
The corner portion is a rounded chamfering die for shaft enlargement processing. A mold for shaft enlargement processing according to claim 1 or 2,
A shaft enlargement processing mold that is integrally attached to and detached from the shaft enlargement processing device. A shaft enlargement processing device for partially enlarging the shaft member by applying compressive stress in the axial direction and repeated shear stress in a direction intersecting the axial direction to the shaft member,
The shaft enlargement processing device includes a pair of holders for holding both ends of the shaft member,
One first holder of the pair of holders is
A mold mounting portion to which the shaft enlargement processing mold according to any one of claims 1 to 3 is fitted, which is fitted to an outer periphery of a first end portion of the shaft member,
An extruding rod that abuts the tip of the first end of the shaft;
Have
A shaft enlargement processing apparatus in which a housing space having a diameter larger than an inner diameter of the shaft enlargement mold is provided between the shaft enlargement mold and the extrusion rod. The shaft enlargement processing device according to claim 4,
The mold mounting portion has a housing hole for housing the first end portion of the shaft member and the shaft enlargement processing mold,
The shaft enlargement processing die is a shaft enlargement processing apparatus in which the extrusion rod is extruded integrally with the shaft member from the accommodation hole by the extrusion rod. The shaft enlargement processing device according to claim 5,
The first holder is
An annular sleeve removably fitted to the outer circumference of the shaft enlargement processing die, and fitted to the inner circumference of the accommodation hole,
An annular washer that surrounds the outer periphery of the accommodation space and is sandwiched between the sleeve and the shaft enlargement processing die and the bottom of the accommodation hole,
A pressing ring sandwiching the sleeve between the washer and fixed to the mold mounting portion,
Shaft enlargement processing device having a. The shaft enlargement processing device according to claim 6,
The sleeve has one or more protrusions protruding from the inner peripheral surface of the sleeve,
A shaft enlargement processing apparatus, wherein a concave portion that engages with the convex portion in the circumferential direction is provided on the outer peripheral surface of the die for axial enlargement processing. The shaft enlargement processing device according to any one of claims 5 to 7,
The first holder is a shaft enlargement processing apparatus having a spacer sandwiched between the die for shaft enlargement processing and the extrusion rod. A pair of shaft enlargement working metals on the outer circumference of the shaft portion of a shaft member having a large diameter portion provided at the first end portion and a small diameter shaft portion extending from the large diameter portion to the second end portion. A mold is fitted and a compressive stress in the axial direction and a repetitive shear stress in a direction intersecting with the axial direction act on an intermediate portion of the shaft portion arranged between the pair of axial hypertrophy processing dies. By doing so, a step of enlarging the intermediate portion of the shaft portion between the pair of shaft enlargement processing dies,
After enlarging the intermediate portion of the shaft portion, a step of removing the shaft member from the pair of shaft enlargement processing dies,
Equipped with
One of the pair of shaft enlargement processing dies arranged on the large diameter portion side is the shaft enlargement processing die, and the shaft enlargement die according to any one of claims 1 to 3. A method for manufacturing a stepped shaft, wherein the shaft material is detached from the shaft enlargement processing mold by separating the shaft enlargement processing mold into a plurality of mold pieces. A method for manufacturing a stepped shaft according to claim 9, wherein
A step of cutting out a portion of the shaft portion extending from the enlarged portion formed by enlarging the intermediate portion to the second end portion side;
A step of joining another shaft member to the enlarged portion,
And a stepped shaft manufacturing method. A large diameter portion provided at the first end of the shaft member,
An enlarged portion provided with a space on the second end side of the shaft member with respect to the large diameter portion,
Provided between the large diameter portion and the enlarged portion, a shaft portion having a smaller diameter than the large diameter portion and the enlarged portion,
Equipped with
A plurality of protrusions are formed at intervals in the circumferential direction on the outer peripheral surface of the annular corner formed by the enlarged portion and the shaft portion, or a step in which a plurality of protrusion removal marks are formed. With axis. The stepped shaft according to claim 11,
A stepped shaft in which another shaft member is joined to the enlarged portion.

Images