JP2009264464A - Assembly type crankshaft and its manufacturing method - Google Patents

Abstract

An object of the present invention is to increase the fastening force of a fastening part in addition to the fastening force due to plastic deformation to prevent the fastening part from coming off.
An assembling type crankshaft is assembled integrally by assembling a plurality of divided pieces together at a fastening portion. The fastening portion includes a hole portion 8 formed in one of the adjacent divided pieces and a shaft portion 6 formed in the other of the adjacent divided pieces. The shaft portion 6 is press-fitted into the hole portion 8 and fastened. The adjacent divided pieces are assembled to each other. A serration 7 is formed on the outer periphery of the shaft portion 6. The serration 7 includes a peak portion and a valley portion that extend in the axial direction and are alternately arranged. This serration 7 is fastened to the inner wall of the hole 8 by plastic deformation. An engagement groove 11 is formed on the end surface of the shaft portion 6 to engage the meat scraped from the inner wall of the hole portion 8 by the tip of the shaft portion 6.
[Selection] Figure 7

Description

  The present invention relates to a crankshaft of an engine, and more particularly to an assembly-type crankshaft in which a plurality of divided pieces are assembled together and a manufacturing method thereof.

  Conventionally, as this type of technology, for example, technologies described in Patent Documents 1 to 5 below are known. In particular, Patent Document 1 describes a crankshaft in which a pair of opposed crank webs are fastened with a crankpin and one end of a piston rod is supported on the crankpin. This crankshaft has a pair of crank webs in which crank pin mounting holes are formed at the eccentric points of the opposing surfaces, a crank pin having a number of irregularities on the outer periphery of one end, and a slit extending in the axial direction on the outer periphery of the other end. Consists of Then, one end of the crank pin is fitted into the mounting hole of one crank web, and is fastened with a tight force by a crank web material in the vicinity of the mounting hole that is locally pressed and plastically deformed around the uneven portion. The other end of the crank pin is fastened with a compression force and a shearing force by a crank web material around the mounting hole that is press-fitted into the mounting hole and plastically deformed by the slit.

JP 62-41419 A Japanese Patent Laid-Open No. 7-259838 Japanese Utility Model No. 2570281 JP 2003-314529 A Japanese Patent Laying-Open No. 2005-61628 JP 2007-146953 A JP 2006-9956 A Japanese Patent Laid-Open No. 10-259755 JP-A-10-266890

  However, the crankshaft described in Patent Document 1 described above has a configuration in which the outer periphery of both ends of the crankpin is fitted into the mounting holes of the crank web and fastened by plastic deformation. For this reason, in the fastening part of a crankpin and a crank web, the intensity | strength more than the fastening intensity | strength by plastic deformation was not obtained, but the intensity | strength lack was a problem. That is, during the operation of the engine, the kinetic force of the piston acting on the crankshaft acts on the fastening portion, but there is a possibility that the fastening force of the fastening portion is insufficient with respect to this motive force.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to increase the fastening force of the fastening portion in addition to the fastening force due to plastic deformation and prevent the fastening portion from coming off. An object of the present invention is to provide a crankshaft and a manufacturing method thereof.

  In order to achieve the above-mentioned object, the invention according to claim 1 is an assembly type crankshaft in which a plurality of divided pieces are assembled to each other at a fastening portion and assembled together, and the fastening portion is adjacent to the divided pieces. Including a hole formed in one of the two and a shaft formed in the other of the adjacent divided pieces, the adjacent divided pieces are assembled together by press-fitting the shaft into the hole and fastening, A plastic fastening portion that is provided on the outer periphery of the shaft portion and is fastened by plastic deformation to the inner wall of the hole portion, and a member that is provided on the end surface of the shaft portion and that engages with meat cut off from the inner wall of the hole portion by the tip end of the shaft portion. The purpose is to have a joint office.

  According to the structure of the said invention, an adjacent division | segmentation piece is mutually assembled | attached by press-fitting a shaft part in a hole part and fastening. Here, when the shaft portion is press-fitted into the hole portion, the plastic fastening portion of the shaft portion fastens with the inner wall of the hole portion while plastically deforming the inner wall of the hole portion, whereby a fastening force due to plastic deformation is obtained. Finally, the end of the shaft portion approaches the bottom wall of the hole portion, and the meat on the inner wall of the hole portion scraped by the tip end of the shaft portion engages with the engaging portion, so that the fastening force due to the engagement is increased. can get.

  To achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the engaging portion is formed in an annular shape along the periphery of the shaft portion at the end surface of the shaft portion, It is intended that the longitudinal section is an engagement groove having a substantially bowl shape.

  According to the configuration of the invention described above, in addition to the operation of the invention according to claim 1, at the end of press-fitting, the tip of the shaft portion approaches the bottom wall of the hole portion, and the hole portion is scraped by the tip of the shaft portion. When the inner wall of the wall enters and engages with the engagement groove, a fastening force by engagement is obtained. Here, since the engagement groove is formed in an annular shape along the periphery of the shaft portion, the scraped meat easily enters the engagement groove. Moreover, since the engaging groove has a substantially bowl shape in the longitudinal section, it is easy to engage the meat that has entered.

  In order to achieve the above object, according to a third aspect of the present invention, in the first aspect of the present invention, the engaging portion is a circular recess formed around the axis of the shaft portion at the end surface of the shaft portion. In addition, the inner peripheral surface of the circular dent is intended to have a tapered shape having a large diameter on the opening end side.

  According to the configuration of the invention described above, in addition to the operation of the invention according to claim 1, at the end of press-fitting, the tip of the shaft portion approaches the bottom wall of the hole portion, and the hole portion is scraped by the tip of the shaft portion. When the inner wall of the wall enters the circular recess and engages with the inner peripheral surface, a fastening force by engagement is obtained. Here, since the inner peripheral surface of the circular recess has a tapered shape, the shaved meat easily enters the circular recess, and the inserted meat easily engages with the inner peripheral surface.

  In order to achieve the above object, according to a fourth aspect of the present invention, in the first aspect of the present invention, the engagement portion includes a plurality of engagements formed near the periphery of the shaft portion on the end surface of the shaft portion. The purpose is to be a hole.

  According to the configuration of the invention described above, in addition to the operation of the invention according to claim 1, at the end of press-fitting, the tip of the shaft portion approaches the bottom wall of the hole portion, and the hole portion is scraped by the tip of the shaft portion. When the inner wall of the wall enters and engages with each engagement hole, a fastening force by engagement is obtained. Here, the engagement hole is easy to process on the end face of the shaft portion.

  In order to achieve the above object, the invention described in claim 5 is that, in the invention described in claim 3, the inner diameter of the hole is made larger than the maximum diameter of the circular recess.

  According to the configuration of the invention described above, in addition to the action of the invention according to claim 1, since the inner diameter of the hole is larger than the maximum diameter of the circular recess, the inner wall of the hole from the initial stage of press-fitting the shaft into the hole. It is less likely to be scraped by the tip of the shaft portion, and the press-fit load in the initial press-fit stage is reduced.

  In order to achieve the above object, the invention described in claim 6 is characterized in that, in the invention described in any one of claims 1 to 5, the bottom edge of the hole portion has a curved surface.

  According to the configuration of the invention described above, in addition to the action of the invention according to any one of claims 1 to 5, the peripheral edge of the bottom surface of the hole portion forms a curved surface, so that the tip of the shaft portion is on the bottom wall of the hole portion. When approaching, the meat scraped off by the tip increases, and the scraped meat curls and becomes easy to engage with the engaging portion.

  In order to achieve the above object, a seventh aspect of the present invention is the invention according to any one of the first to fifth aspects, wherein the peripheral edge of the bottom surface of the hole portion is a tapered surface.

  According to the configuration of the invention, in addition to the action of the invention according to any one of claims 1 to 5, the peripheral edge of the bottom surface of the hole portion forms a tapered surface, so that the tip of the shaft portion is on the bottom wall of the hole portion. When approaching, the meat scraped off by the tip increases, and the scraped meat curls and becomes easy to engage with the engaging portion.

  In order to achieve the above object, the invention according to claim 8 is the method for manufacturing the assembly type crankshaft according to claim 1, wherein when the shaft portion is press-fitted into the hole portion, the hole portion is formed by the plastic fastening portion. The inner wall of the hole is fastened to the plastic fastening portion while being plastically deformed, and finally the meat of the inner wall of the hole portion scraped off by the tip of the shaft portion is engaged with the engaging portion.

  According to the configuration of the above invention, when the shaft portion is press-fitted into the hole portion, the plastic fastening portion is fastened to the plastic fastening portion while the inner wall of the hole portion is plastically deformed, whereby a fastening force due to plastic deformation is obtained. Finally, by engaging the flesh of the inner wall of the hole portion scraped off by the tip of the shaft portion with the engaging portion, a fastening force by engagement is further obtained.

  According to the first aspect of the present invention, in addition to the fastening force due to plastic deformation, the fastening force of the fastening portion can be increased by the amount of the fastening force due to engagement, and the fastening portion can be prevented from coming off.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the fastening force by engagement can be increased.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, the fastening force by engagement can be increased.

  According to invention of Claim 4, in addition to the effect of invention of Claim 1, manufacture of a division piece can be made easy.

  According to the invention described in claim 5, in addition to the effect of the invention described in claim 3, the cycle time for fastening the shaft portion and the hole portion can be shortened.

  According to the invention described in claim 6, in addition to the effect of the invention described in any one of claims 1 to 5, the fastening force by engagement can be further increased.

  According to the invention described in claim 7, in addition to the effect of the invention described in any one of claims 1 to 5, the fastening force by engagement can be further increased.

  According to the eighth aspect of the invention, in addition to the fastening force due to plastic deformation, the fastening force of the fastening portion can be increased by the amount of the fastening force due to engagement, and the fastening portion can be prevented from coming off. In addition, the manufacturing process can be simplified.

[First Embodiment]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment that embodies an assembly-type crankshaft and a manufacturing method thereof according to the present invention will be described below in detail with reference to the drawings. In this embodiment, the present invention will be described in the form of an assembly type crankshaft for a four-cylinder engine.

  FIG. 1 is a side view of an assembled crankshaft 1 according to this embodiment. This assembled crankshaft 1 is configured by assembling nine divided pieces 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, and 2I together by fastening portions 3 and assembling them integrally. In FIG. 1, the first divided piece 2A, the third divided piece 2C, the fifth divided piece 2E, and the seventh divided piece 2G have the same shape as each other from the left side, and have a thick plate-like counterweight portion 4 and a columnar shape. A journal unit 5; The journal unit 5 is disposed at a substantially central portion of the counterweight unit 4. A shaft portion 6 is provided at the tip of the journal portion 5. A serration 7 is formed on the outer periphery of the shaft portion 6. A hole 8 is formed at a position near one end of the counterweight 4. In this embodiment, for example, "S45C" or "S35C" forged products containing an appropriate amount of carbon can be used for each of the divided pieces 2A to 2I.

  In FIG. 1, the second divided piece 2B, the fourth divided piece 2D, the sixth divided piece 2F, and the eighth divided piece 2H have the same shape from the left side, and have a thick plate-like counterweight portion 4 and a pin portion 9. With. The pin portion 9 is disposed at a position near one end of the counterweight portion 4. A shaft portion 6 is provided at the tip of the pin portion 20. Serrations (not shown) are formed on the outer periphery of the shaft portion 6 in the same manner as described above. A hole 8 is formed at the center of the counterweight portion 4.

  In FIG. 1, the ninth divided piece 2I at the right end has a different shape from the other divided pieces 2A to 2H. The ninth divided piece 2 </ b> I includes a journal part 5, a shaft part 6 formed at the tip of the journal part 5, and a flange part 10 formed at the other end of the journal part 5. Serrations (not shown) are formed on the outer periphery of the shaft portion 6 in the same manner as described above.

  In this embodiment, each fastening portion 3 includes a hole portion 8 formed in one of the adjacent divided pieces 2A to 2H and a shaft portion 6 formed in the other of the adjacent divided pieces 2A to 2I. Each fastening part 3 is fastened by press-fitting the shaft part 6 into the hole part 8 and assembling it.

  2 and 3, as an example, an assembling process of the adjacent first divided piece 2A and second divided piece 2B is shown in a side view. As shown in FIG. 2, the assembly of the two divided pieces 2A and 2B is performed by aligning the shaft portion 6 of the second divided piece 2B with the hole 8 of the first divided piece 2A, and then, as shown in FIG. This is done by press-fitting and fastening the shaft portion 6 of the second divided piece 2B into the hole portion 8 of the one divided piece 2A. The assembly of the third divided piece 2C to the ninth divided piece 2I is also performed in a process according to the above.

  The assembled crankshaft 1 of this embodiment is particularly characterized by the configuration of the shaft portion 6. In FIG. 4, the axial part 6 of each division | segmentation piece 2A-2I is partially broken, and is shown with a side view. In FIG. 5, the front-end | tip of the axial part 6 is shown with a front view. FIG. 6 shows an enlarged view of the portion of the chain line circle S1 in FIG. FIG. 7 is a side view of the first divided piece 2A and the second divided piece 2B adjacent to each other, with the shaft portion 6 and the hole portion 8 before fastening partially broken. In FIG. 8, the shaft part 6 and the hole part 8 after fastening are partially broken and shown in a side view. That is, as shown in FIGS. 4 and 5, serrations 7 are provided on the outer periphery of the shaft portion 6 as plastic fastening portions that are fastened to the inner wall of the hole portion 8 by plastic deformation. The serration 7 includes a plurality of crests 7a and troughs 7b that extend in the axial direction of the shaft 6 and are alternately arranged. The hardness can be increased by quenching the surface of the serration 7. In addition, an engagement groove 11 is provided on the distal end surface of the shaft portion 6 as an engagement portion that engages the meat scraped from the inner wall of the hole portion 8 by the distal end of the shaft portion 6. The engaging groove 11 is formed in an annular shape along the periphery of the shaft portion 6 at the end surface of the shaft portion 6 as shown in FIG. 5, and the vertical section is substantially bowl-shaped as shown in FIGS. I am doing. In this embodiment, the engagement groove 11 has an L shape whose longitudinal section is bent at right angles to the radial direction of the shaft portion 6. Moreover, as shown in FIG. 7, the hole 8 of this embodiment forms a square surface whose bottom surface periphery intersects the bottom surface and the inner peripheral surface at a right angle.

  Therefore, according to the assembly type crankshaft 1 of this embodiment, in order to fasten the hole portion 8 formed in one of the adjacent divided pieces 2A to 2I and the shaft portion 6 formed in the other, FIG. As shown in FIG. 8, after the shaft portion 6 is aligned with the hole portion 8, the shaft portion 6 is press-fitted into the hole portion 8 as shown in FIG. Then, during this press-fitting, the inner wall of the hole 8 is fastened to the serration 7 while plastically deforming the inner wall of the hole 8 by the serration 7, and finally the inner wall of the hole 8 scraped by the tip of the shaft 6 is engaged with the engagement groove 11. By joining, the shaft portion 6 and the hole portion 8 are fastened. During the press-fitting process, the peak 7a of the serration 7 bites into the inner wall of the hole 8, and the meat on the inner wall of the hole 8 is pushed by the peak 7a and enters the valley 7b. Thus, the hole 8 and the shaft 6 are fastened by plastic deformation by deforming the inner wall of the hole 8 by plastic flow and engaging the serration 7 of the shaft 6. By this fastening, a fastening force due to plastic deformation is obtained at the fastening portion 3. Then, at the end of the press-fitting, the tip of the shaft portion 6 approaches the bottom wall 8a of the hole portion 8, and the meat 12 on the inner wall of the hole portion 8 scraped by the tip of the shaft portion 6 enters the engagement groove 11 and engages. Match. Thereby, the fastening part 3 is further provided with a fastening force by engagement. As a result, in addition to the fastening force due to plastic deformation, the fastening force of the fastening portion 3 can be increased by the amount of the fastening force due to the engagement, thereby preventing the fastening portion 3 from coming off. That is, with respect to the fastening force due to plastic deformation between the serration 7 and the inner wall of the hole 8, the fastening force due to the engagement between the engagement groove 11 and the meat 12 scraped from the inner wall of the hole 8 is increased. The fastening portion 3 can be made difficult to come off by the amount of fastening force due to the engagement. For this reason, when the assembly-type crankshaft 1 is used for an engine, the movement force of the piston acts on each journal portion 5 and each pin portion 9 of the assembly-type crankshaft 1 when the engine is operated, and the fastening portions 3 are fastened. Even if a force is applied in the direction in which the bolts come out, a firm fastening state of each fastening portion 3 can be ensured.

  In this embodiment, since the engagement groove 11 is formed in an annular shape along the periphery of the shaft portion 6, even the meat 12 that is irregularly cut off from the inner wall of the hole portion 8 is formed in the engagement groove 11. Easy to get inside. In addition, since the engagement groove 11 has a substantially bowl-shaped (L-shaped) vertical cross section, the meat 12 that enters the engagement groove 11 is easily engaged with the engagement groove 11. In that sense, the fastening force due to the engagement between the shaved meat 12 and the engaging groove 11 can be increased.

  Further, in this embodiment, when the shaft portion 6 and the hole portion 8 are fastened, there is no need for processes other than press-fitting the shaft portion 6 into the hole portion 8, and the manufacturing process can be simplified.

[Second Embodiment]
Next, a second embodiment that embodies the assembly-type crankshaft and the manufacturing method thereof according to the present invention will be described in detail with reference to the drawings. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Hereinafter, different points will be mainly described.

  In FIG. 9, the shaft part 6 and the hole part 8 before fastening are partially broken and shown in a side view. FIG. 10 is a side view of the shaft portion 6 and the hole portion 8 in the middle of press-fitting, which are partially broken. In FIG. 11, the shaft part 6 and the hole part 8 after fastening are partially broken and shown in a side sectional view. As shown in FIG. 9, this embodiment differs from the first embodiment in that the periphery of the bottom surface 8a of the hole 8 forms a curved surface 8b.

  Therefore, also in the assembly type crankshaft 1 of this embodiment, in order to fasten the hole portion 8 and the shaft portion 6 to each other, the shaft portion 6 is aligned with the hole portion 8 as shown in FIG. As shown, by pressing the shaft portion 6 into the hole portion 8, the same effect as the first embodiment can be obtained.

  In addition, in this embodiment, since the peripheral edge of the bottom surface 8a of the hole portion 8 forms a curved surface 8b, when the tip end of the shaft portion 6 approaches the bottom surface 8a of the hole portion 8, as shown in FIG. Will hit the part of the curved surface 8b as soon as possible, and the meat 12 scraped off by the tip of the shaft portion 6 will increase, and the scraped meat 12 will curl and easily engage with the engaging groove 11. In this sense, the fastening force due to the engagement can be further increased than that of the first embodiment, and the fastening force of the fastening portion 3 can be further increased than that of the first embodiment.

[Third Embodiment]
Next, a third embodiment that embodies the assembly-type crankshaft and the manufacturing method thereof according to the present invention will be described in detail with reference to the drawings.

  In FIG. 12, the shaft part 6 and the hole part 8 before fastening are partially broken and shown in a side view. In FIG. 13, the front-end | tip of the axial part 6 is shown with a front view. In FIG. 14, the shaft part 6 and the hole part 8 after fastening are partially broken and shown in a side sectional view. This embodiment is different from the first embodiment in the configuration of the shaft portion 6 as shown in FIG. That is, in this embodiment, as the engaging portion of the present invention, the circular recess 13 is formed around the axis of the shaft portion 6 at the end surface of the shaft portion 6. The circular recess 13 is formed so as to occupy most of the end surface of the shaft portion 6. The inner peripheral surface 13a of the circular recess 13 has a tapered shape in which the opening end side has a large diameter. In this embodiment, the inner diameter Dh of the hole 8 is set larger than the maximum diameter Dt of the circular recess 13 as shown in FIG.

  Therefore, in order to fasten the hole 8 and the shaft 6 to each other in the assembly type crankshaft 1 of this embodiment, the shaft 6 is aligned with the hole 8 as shown in FIG. 12, and as shown in FIG. The shaft portion 6 is press-fitted into the hole portion 8. In this press-fitting process, the inner wall of the hole 8 is deformed by plastic flow and engaged with the serration 7 of the shaft 6, so that the hole 8 and the shaft 6 are fastened by plastic deformation, and the fastening force is increased. can get. At the end of the press-fitting, the tip end of the shaft portion 6 approaches the bottom surface 8a of the hole portion 8, and the meat 12 on the inner wall of the hole portion 8 scraped by the tip end of the shaft portion 6 enters the circular recess 13 to By engaging with the peripheral surface 13a, a fastening force by the engagement is further obtained. As a result, as in the first embodiment, in addition to the fastening force due to plastic deformation, the fastening force of the fastening portion 3 can be increased by the amount of the fastening force due to engagement, thereby preventing the fastening portion 3 from coming off. Can do.

  In particular, in this embodiment, the circular recess 13 formed on the end face of the shaft portion 6 has a tapered inner peripheral surface 13 a, so that the meat 12 scraped from the inner wall of the hole portion 8 is formed by the circular recess 13. It is easy to enter inside, and the meat 12 that has entered easily engages with the inner peripheral surface 13a. The meat 12 engaged with the inner peripheral surface 13a elastically deforms the peripheral portion of the circular recess 13 in the radial direction. For this reason, the fastening force due to the engagement between the circular recess 13 and the shaved meat 12 can be increased more than that of the first embodiment, so that the fastening force of the fastening portion 3 is the same as that of the first embodiment. It can be increased more than that.

  In this embodiment, the circular recess 13 is formed by simply denting the end surface of the shaft portion 6. For this reason, the engagement groove 11 of the first embodiment needs to be processed by cutting, whereas the circular recess 13 of this embodiment can be formed by plastic processing other than cutting. In this sense, the process for producing each of the divided pieces 2A to 2I including the shaft portion 6 can be simplified.

  Furthermore, in this embodiment, since the inner diameter Dh of the hole portion 8 is larger than the maximum diameter Dt of the circular recess 13, the inner wall of the hole portion 8 is formed by the tip of the shaft portion 6 from the initial stage of press-fitting the shaft portion 6 into the hole portion 8. It is less likely to be scraped off, and the press-fitting load of the shaft portion 6 at the initial press-fitting stage is reduced. As a result, the shaft portion 6 can be smoothly press-fitted into the hole portion 8, and the cycle time for fastening the shaft portion 6 and the hole portion 8 can be shortened.

  The present invention is not limited to the embodiments described above, and can be implemented as follows by appropriately changing a part of the configuration without departing from the spirit of the invention.

  (1) In each of the above embodiments, the present invention is embodied in the assembly type crankshaft 1 for a four-cylinder engine. However, the present invention is embodied in an assembly type crankshaft for an engine having a number of cylinders other than four cylinders. It can also be converted.

  (2) In the second embodiment, the periphery of the bottom surface 8a of the hole 8 is formed on the curved surface 8b. However, as shown in FIG. 15, the periphery of the bottom surface 8a of the hole 8 is formed on the tapered surface 8c. Also good. In this case, the same effect as that of the second embodiment can be obtained.

  (3) In the first embodiment, as the engaging portion provided on the end surface of the shaft portion 6, as shown in FIG. 6, the engaging groove 11 whose longitudinal section forms an L shape is provided. On the other hand, as shown in FIGS. 16 and 17, as the engaging portion provided on the end surface of the shaft portion 6, the engaging grooves 14 and 15 having a trapezoidal longitudinal section are provided, or as shown in FIG. A circular dent 16 having a trapezoidal longitudinal section may be provided. In these cases, the same effects as the first embodiment can be obtained.

  (4) In the said 3rd Embodiment, the internal peripheral surface 13a of the circular dent 13 formed in the end surface of the axial part 6 was formed in the taper shape which becomes a large diameter toward an opening end side. On the other hand, as shown in FIG. 19, the inner peripheral surface 13 a of the circular recess 13 may be formed to be perpendicular to the bottom surface of the circular recess 13. In this case, the inner diameter of the circular recess 13 defined by the inner peripheral surface 13 a is the maximum inner diameter Dt of the circular recess 13. In this case, the same effect as that of the third embodiment can be obtained.

  (5) In the first embodiment, as the engaging portion provided on the end surface of the shaft portion 6, the engaging groove 11 having a vertical cross-sectional shape is provided. On the other hand, as shown in FIGS. 20 and 21, a plurality of engagement holes 17 formed in the vicinity of the periphery of the shaft portion 6 on the end surface of the shaft portion 6 may be provided as the engagement portion. In this case, each engagement hole 17 may be arranged in alignment with the peak portion 7 a of the serration 7. Moreover, it is not necessary to provide the engagement holes 17 corresponding to all of the peak portions 7a, and the number of the engagement holes 17 can be set as appropriate. In this case, the same effect as that of the first embodiment can be obtained. In addition, each of the engagement holes 17 can be easily processed with respect to the end surface of the shaft portion 6, so that the division pieces 2 </ b> A to 2 </ b> I can be easily manufactured.

  (6) In each of the above embodiments, the serration 7 is provided as the plastic fastening portion of the shaft portion 6, but the present invention is not limited to this, and the plastic fastening is achieved by making the outer periphery of the shaft portion uneven such as a mesh shape. It can also be a part.

The side view which concerns on 1st Embodiment and shows an assembly-type crankshaft. Similarly, the side view which shows the assembly | attachment process of a 1st division piece and a 2nd division piece. Similarly, the side view which shows the assembly | attachment process of a 1st division piece and a 2nd division piece. Similarly, the side view which cuts and shows a shaft part partially. Similarly, the front view which shows the front-end | tip of an axial part. Similarly, the side view which expands and shows the part of the chain line circle of FIG. Similarly, the side view which shows the shaft part and the hole part before the fastening partly broken and shows. Similarly, the side view which shows a partially broken shaft and hole after fastening. The side view which concerns on 2nd Embodiment and shows a partially broken shaft part and hole before fastening. Similarly, the side view which shows a shaft part and a hole part in the middle of press-fitting partially broken. Similarly, the side view which shows a partially broken shaft and hole after fastening. The side view which concerns on 3rd Embodiment and shows a partially broken shaft part and hole part before fastening. Similarly, the front view which shows the front-end | tip of an axial part. Similarly, the side view which shows a partially broken shaft and hole after fastening. The side view which concerns on another embodiment and shows a partially broken shaft part and hole part before fastening. The side view which concerns on another embodiment and expands and shows a part of axial part. The side view which concerns on another embodiment and expands and shows a part of axial part. The side view which concerns on another embodiment and expands and shows a part of axial part. The side view which concerns on another embodiment and shows a partially broken shaft portion. The side view which concerns on another embodiment and shows a partially broken shaft portion. Similarly, the front view which shows the front-end | tip of the axial part of FIG.

Explanation of symbols

1 assembling-type crankshaft 2A first divided piece 2B first divided piece 2C first divided piece 2D first divided piece 2E first divided piece 2F first divided piece 2G first divided piece 2H first divided piece 2I first divided piece 3 Fastening part 6 Shaft part 7 Serration (plastic fastening part)
8 hole portion 8a bottom surface 8b curved surface 8c taper surface 11 engagement groove (engagement portion)
12 Machined meat 13 Circular dent (engagement part)
13a Inner peripheral surface 14 Engagement groove (engagement part)
15 Engaging groove (engaging part)
16 Circular dent (engagement part)
17 Engagement hole (engagement part)

Claims (8)

An assembly-type crankshaft in which a plurality of divided pieces are assembled together by assembling together at a fastening portion,
The fastening portion includes a hole formed in one of the adjacent divided pieces and a shaft formed in the other of the adjacent divided pieces, and press-fits the shaft into the hole and fastens. The adjacent divided pieces are assembled to each other by
A plastic fastening portion provided on an outer periphery of the shaft portion and fastened by plastic deformation with an inner wall of the hole portion;
An assembly type crankshaft comprising an engaging portion provided on an end surface of the shaft portion and engaging with a meat scraped off from an inner wall of the hole portion by a tip of the shaft portion. The engagement portion is an engagement groove formed in an annular shape along a peripheral edge of the shaft portion at an end surface of the shaft portion, and having a vertical cross-section of a substantially bowl shape. Assembling type crankshaft. The engaging portion is a circular recess formed around an axis of the shaft portion at an end surface of the shaft portion, and an inner peripheral surface of the circular recess has a tapered shape with a large diameter on an opening end side thereof. The assembly-type crankshaft according to claim 1. The assembly type crankshaft according to claim 1, wherein the engagement portion is a plurality of engagement holes formed in the vicinity of a peripheral edge of the shaft portion on an end surface of the shaft portion. 4. The assembly type crankshaft according to claim 3, wherein an inner diameter of the hole is larger than a maximum diameter of the circular recess. The assembly type crankshaft according to any one of claims 1 to 5, wherein a peripheral edge of the bottom surface of the hole portion forms a curved surface. The assembly type crankshaft according to any one of claims 1 to 5, wherein a peripheral edge of the bottom surface of the hole portion has a tapered surface. It is a manufacturing method of the assembly-type crankshaft of Claim 1,
When the shaft portion is press-fitted into the hole portion, the plastic fastening portion is fastened to the plastic fastening portion while the inner wall of the hole portion is plastically deformed by the plastic fastening portion, and finally the hole portion scraped off by the tip of the shaft portion. A method for manufacturing an assembly-type crankshaft, characterized in that a meat of an inner wall is engaged with the engaging portion.

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