JP5231048B2 - Hollow shaft member and method for forming the same - Google Patents

Description

  The present invention relates to a hollow shaft member formed from a solid material and formed by drawing the tip end side in the axial direction to a small diameter and / or forming a tooth profile on a part of the outer peripheral surface in the axial direction. The present invention relates to the molding method.

  As a method for molding this type of hollow shaft member, there is a molding method previously proposed as Patent Document 1 by the applicant of the present invention.

  In this conventional molding method, as shown in FIGS. 1 and 2, both ends in the axial direction of a solid rod-shaped material 1 are formed by upper and lower molds 3 and 4 each having an annular space portion 2 at an opposing portion. The mold is held in a clamped state, and then pressed by upper and lower punches 5 and 6 having a smaller diameter than that of the material 1 so as to extrude holes by the punches 5 and 6 from both sides in the axial direction of the material 1 and A hollow shaft member having a stepped large-diameter portion 7 at the intermediate portion in the axial direction is formed by bulging and deforming in a step shape at a portion facing the space portion 2. At this time, the plug-like portion 8 formed between the opposing punches 5 and 6 is removed by pushing one of the punches to form a first molded body 9a of a hollow shaft member as shown in FIG. 3, for example. (See Patent Document 1).

Japanese Patent Laying-Open No. 2005-040842

  In the first molded body 9a of the hollow shaft member molded as described above, the upper mold 10 and the lower mold 11 have a small diameter on both sides in the axial direction from the position where the stepped large diameter portion 7 is located as shown in FIG. To form a second molded body 9b having small-diameter portions 12 and 13 on both sides in the axial direction. Further, as shown in FIG. 5, serrations 14 are formed on the outer periphery of the intermediate portion of the second molded body 9b. The mold 15 may be extruded in the axial direction to form a third molded body 9c.

  In the above-described molding process, for example, as shown in FIG. 6, when the first molded body 9a is clamped in the axial direction with the upper and lower molds 10, 11, and the small diameter parts 12, 13 are molded on both sides in the axial direction, When the first molded body 9a is hollow, buckling may occur in the intermediate portion, and the bulging portion 16 may occur as shown by the chain line in FIG.

  Further, when the serration 14 is formed on the outer periphery of the second molded body 9b shown in FIG. 4 and molded into the third molded body 9c, as in the molding of the second molded body 9b, Since this portion is hollow, the backup force at the time of extrusion molding by the lower mold 11 is insufficient, and it is difficult to obtain the molding accuracy of the tooth profile of the serration 14. It should be noted that a cored bar may be inserted into this part, but since the both ends in the axial direction of the second molded body 9a are smaller in diameter than the intermediate part, molding cannot be performed by inserting the cored bar into the hollow part.

  The present invention has been made in view of the above, and provides a hollow shaft member capable of accurately molding a small-diameter portion and a tooth profile portion on an axial tip side formed from a solid material, and a molding method thereof. It is for the purpose.

In order to achieve the above object, a hollow shaft member according to the present invention has a stepped large diameter portion and a medium diameter portion on the outer periphery, and has a hollow portion having the same diameter inside the stepped large diameter portion and the medium diameter portion . In a hollow shaft member provided by plastic forming , tooth shapes such as serrations and gears are provided on the outer periphery of the medium diameter portion adjacent to the stepped large diameter portion, and the axial length of the tooth shape is provided in the hollow portion of the portion where the tooth shape is provided. The plug-shaped portion having an axial length smaller than the axial length of the tooth profile is provided.

In addition, it has a stepped large diameter part and a medium diameter part on the outer periphery, a small diameter part made smaller in diameter than the other parts on the outer periphery of the axial end, and inside the stepped large diameter part and the medium diameter part In a hollow shaft member in which a hollow portion having the same diameter is formed by plastic forming a hollow portion having a smaller diameter than the hollow portion inside the small diameter portion , serrations, gears, etc. are provided on the outer periphery of the medium diameter portion adjacent to the stepped large diameter portion. A tooth shape is provided, and a plug-like portion having an axial length that is within the axial length of the tooth shape and smaller than the axial length of the tooth shape is provided in the hollow portion of the portion where the tooth shape is provided. .

The hollow shaft member is formed by holding a solid rod-shaped material in the upper and lower molds, pressing it from the axial direction with upper and lower punches having a smaller diameter than the material , and forming a stepped large diameter portion on the outer periphery. A hollow shaft member that has a medium-diameter portion and is formed by plastic forming a step-shaped large-diameter portion and a hollow portion and a plug-shaped portion of the same diameter inside the medium-diameter portion, is adjacent to the step-shaped large-diameter portion A hollow shaft member molding method in which a tooth shape such as a serration or a gear is plastically formed on the outer periphery of the medium diameter portion , wherein the plug-like portion is within the axial length of the tooth profile and is smaller than the axial length of the tooth profile. Small axial length .

Moreover, holding a solid rod-like material into the mold up and down, and pressed from the axial direction from the material at the small diameter of the upper and lower punches having a stepped large-diameter portion and the intermediate-diameter portion on the outer periphery, A hollow shaft member in which a hollow portion and a plug-like portion having the same diameter are formed by plastic molding inside the stepped large diameter portion and the medium diameter portion is extruded, and then the stepped large diameter portion at the end in the axial direction is formed. A hollow shaft that plastically forms serrations, gears, and other tooth profiles on the outer periphery of the medium-diameter portion adjacent to the stepped large-diameter portion while the outer periphery of the medium-diameter portion on the non-adjacent side is narrowed to a smaller-diameter portion that is smaller than other portions In the method for forming a member, the plug-like portion has an axial length that is within the axial length of the tooth profile and is smaller than the axial length of the tooth profile .

  According to the hollow shaft member of the first aspect of the present invention, when the tooth profile is processed on the outer periphery of the hollow shaft member, it is backed up by the plug member provided inside this portion, and serration or gear molding by plastic molding is performed. Can be performed with high accuracy.

  In addition, the hollow shaft member according to claim 2 can be molded by plastic molding from the axial direction without causing buckling of the small diameter portion of the axial end portion.

  According to the molding method of claim 3 and claim 4, a hollow shaft member formed by plastic molding a tooth shape such as a serration or a gear on the outer periphery of a part of the axial direction and a small diameter smaller than the other part at the axial end. It is possible to easily form the plug-like portion inside each plastic forming portion of the hollow shaft member formed by plastic forming the portion.

  An embodiment of the present invention will be described below with reference to FIG. Note that the same mold as the mold used in the description of the conventional molding method shown in FIGS. 1 to 6 is given the same reference numeral.

  FIG. 7 shows a state during molding of the conventional first molded body 9a shown in FIG. 3, that is, a state before punching out the plug-like portion 8 shown in FIG. In this embodiment, the extrusion position of the upper punch 5 is controlled so that the plug-like portion 8 is formed between the small-diameter portion 13 and the step-like large-diameter portion 7 formed on one shaft end portion shown in FIG. The first molded body 9a ′ positioned at is formed.

  8, the first molded body 9 a ′ is molded with small diameter portions 12 and 13 on both sides in the axial direction by the upper and lower molds 10 and 11 in the same manner as the conventional second molded body 9 b shown in FIG. 6. The middle of molding is shown.

  At this time, since the intermediate portion of the hollow portion below the stepped large diameter portion 7 is solid at the plug-like portion 8, buckling occurs in the hollow portion as shown in FIG. The small-diameter portion 13 is formed by extrusion molding using the lower mold 11 from the axial direction, thereby forming the second molded body 9b ′.

  FIG. 10 shows a state where the serration 14 is formed between the stepped large-diameter portion 7 and the small-diameter portion 13 in the same manner as the conventional third molded body 9c shown in FIG. Show.

  At this time, since the portion where the serration 14 is molded is solid at the plug-shaped portion 8, the molding of the serration 14 is backed up by the plug-shaped portion 8 and molded with high accuracy. .

  FIG. 11 shows a hollow gear shaft 18 obtained by processing the gear 17 on the stepped large diameter portion 7 using the above-described second molded body 9c ′, and an oil that communicates the inside and outside of the shaft on both sides in the axial direction of the gear 17. A hole 19 is provided.

  In the hollow gear shaft 18, the lubricating oil supplied to the hollow portion inside the gear 17 is supplied to the meshing portion of the gear 17 through the oil hole 19. At this time, the lubricating oil supplied to the hollow portion is blocked from coming off in the axial direction by the plug-like portion 8, and the entire amount thereof flows out from the oil hole 19, and the supplied lubricating oil is transferred to the other. It is used effectively without being washed away.

It is sectional drawing which shows the holding | maintenance state of a raw material, and an intermediate process with the shaping | molding method of the hollow shaft part which has a step-shaped large diameter part. It is sectional drawing which shows the state which provided the plug-shaped part in the position of the step-shaped large diameter part. It is sectional drawing which shows the hollow shaft member which punched the stopper-shaped part. It is sectional drawing which shows the shaping | molding process which provides a small diameter part in an axial direction both ends. It is sectional drawing which shows the formation process which provides a serration in outer periphery. It is explanatory drawing which shows the mode of a buckling when extruding a small diameter part to an axial direction. It is sectional drawing which shows the state which provided the stopper member in the specific position. It is sectional drawing which shows the intermediate process of this invention method. It is sectional drawing which shows the shaping | molding method of the hollow shaft member which shape | molded the small diameter part by the method of this invention. It is sectional drawing which shows the shaping | molding method of the hollow shaft member which shape | molded the serration by the method of this invention. It is sectional drawing which shows the hollow shaft member which provided the oil hole in the one side with respect to the position which provided the plug member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Material, 2 ... Annular space part, 3, 4, 10, 11, 15 ... Mold, 5, 6 ... Punch, 7 ... Stepped large diameter part, 8 ... Plug member, 9a, 9b, 9c, 9a ' , 9b ', 9c' ... molded body, 12, 13 ... small diameter part, 14 ... serration, 16 ... bulge part, 17 ... gear, 18 ... hollow gear shaft, 19 ... oil hole.

Claims (4)

In a hollow shaft member having a stepped large diameter portion and a medium diameter portion on the outer periphery, and providing a hollow portion of the same diameter inside the stepped large diameter portion and the medium diameter portion by plastic molding,
A tooth profile such as serrations and gears is provided on the outer periphery of the medium diameter portion adjacent to the stepped large diameter portion, and the hollow portion of the portion where the tooth shape is provided is within the axial length of the tooth profile and the axial direction of the tooth profile A hollow shaft member provided with a plug-like portion having an axial length smaller than the length . It has a stepped large diameter part and a medium diameter part on the outer periphery, a small diameter part made smaller in diameter than other parts on the outer periphery of the axial end, and the same diameter inside the stepped large diameter part and the medium diameter part A hollow shaft member in which a hollow portion having a smaller diameter than that of the hollow portion is formed by plastic molding inside the small diameter portion ,
A tooth profile such as serrations and gears is provided on the outer periphery of the medium diameter portion adjacent to the stepped large diameter portion, and the hollow portion of the portion where the tooth shape is provided is within the axial length of the tooth profile and the axial direction of the tooth profile A hollow shaft member provided with a plug-like portion having an axial length smaller than the length . A solid rod-shaped material is held in the upper and lower molds, pressed from the axial direction with upper and lower punches with a smaller diameter than this material , and has a stepped large diameter portion and a medium diameter portion on the outer periphery. A hollow shaft member in which a hollow portion and a plug-like portion of the same diameter are provided by plastic forming inside the diameter portion and the medium diameter portion is extruded, and serrations and gears are formed on the outer periphery of the medium diameter portion adjacent to the stepped large diameter portion. A method of forming a hollow shaft member that plastically molds a tooth profile such as a plug-shaped portion having an axial length that is within the axial length of the tooth profile and smaller than the axial length of the tooth profile. A method for forming a hollow shaft member. A solid rod-shaped material is held in the upper and lower molds, pressed from the axial direction with upper and lower punches with a smaller diameter than this material , and has a stepped large diameter portion and a medium diameter portion on the outer periphery. A hollow shaft member in which a hollow portion and a plug-like portion having the same diameter are formed by plastic forming inside the diameter portion and the medium diameter portion is extruded, and then is not adjacent to the stepped large diameter portion at the end in the axial direction. Forming a hollow shaft member that plastically forms teeth such as serrations and gears on the outer periphery of the medium diameter part adjacent to the stepped large diameter part while reducing the outer diameter of the medium diameter part on the side to a smaller diameter part that is smaller than other parts A method for forming a hollow shaft member, characterized in that the plug-like portion has an axial length within a range of the axial length of the tooth profile and smaller than the axial length of the tooth profile .

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