JP2008121775A - Manufacturing method of rotary shaft for water pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for sufficiently reducing manufacturing cost by improving a material yield and shortening a machining time. <P>SOLUTION: A multistage former machines a second raw material shown in Fig.1(A) through a preliminary intermediate raw material 15 shown in (B) and an intermediate raw material 16 shown in (C) into a second intermediate raw material 17 shown in (D). Such a series of machining are all performed with cold work. In upsetting work shown in (C) out of these, excessive thicknesses are gathered in a gap 28 between a pair of upsetting dies 27a, 27b to form a protruded portion which is crushed in a handling process shown in (D). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  This invention is incorporated in a water pump for circulating engine cooling water, and a rotation axis of a water pump for transmitting rotation of a driven pulley driven by the engine to an impeller for circulating cooling water. The present invention relates to an improvement of a manufacturing method.

  As a water pump for circulating the cooling water of an automobile engine, a water pump having a structure as shown in FIGS. The cylindrical housing 1 has a mounting flange 2 formed on the outer peripheral surface thereof (the inner side in the axial direction means the side closer to the engine, the lower side in FIGS. 1 to 3, the right side in FIGS. 4 to 6). Utilized, it is fixed to the cylinder block of the engine. On the inner diameter side of the housing 1, the rotating shaft 3 is arranged on the inner side with the ball bearing 4 on the inner side (the outer side in the axial direction is the side far from the engine, and is the upper side in FIGS. 1 to 3 and the left side in FIGS. 4 to 6). The roller bearing 5 is combined with a roller bearing 5 and is rotatably supported. In addition, this rolling bearing unit may be comprised by the double row ball array as described in patent document 1, for example.

  Further, seal rings 7 and 7 are provided at both ends of the rolling bearing unit 6 in the axial direction (left and right direction in FIGS. 5 to 6) to prevent leakage of grease sealed inside, dust, water vapor, etc. existing outside. To prevent intrusion of foreign matter. A pulley 8 is fixed to a portion protruding from the outer end opening of the housing 1 near the outer end of the rotating shaft 3. In an assembled state to the engine, a belt (not shown) is stretched over the pulley 8 and the rotary shaft 3 is rotationally driven by the crankshaft of the engine.

  On the other hand, an impeller 9 is fixed to a portion protruding from the inner surface of the mounting flange 2 at the inner end of the rotating shaft 3. The impeller 9 enters the inside of a water jacket provided in the cylinder block in a state where the mounting flange 2 is fixed to the cylinder block of the engine. Then, as the rotary shaft 3 rotates, the cooling water in the water jacket is circulated with a radiator or the like (not shown).

  Further, a mechanical seal 10 is provided between the outer peripheral surface of the rotating shaft 3 and the inner peripheral surface of the housing 1. The mechanical seal 10 prevents the hot water containing water vapor flowing in the water jacket from leaking outside while allowing the rotation of the rotating shaft 3 during operation of the engine. The water pump described above is driven together with the cooling fan by fixing the cooling fan outside the pulley 8 of the rotating shaft 3 as described in Patent Document 2, for example. There is also a case.

  In the case of the structure shown in FIGS. 5 to 6 described above, the rotary shaft 3 is made of metal such as bearing steel, and each is formed by integrally forming a solid small-diameter shaft portion 11 and a large-diameter shaft portion 12. It is. Among these, the large-diameter shaft portion 12 forms the inner ring raceways 36 and 36a constituting the rolling bearing unit 6 on the outer peripheral surface, and each of the ball bearing 4 and the bearing 5, and the pulley on a part of the outer peripheral surface. 8 is fixed. In some cases, a cooling fan is fixed to the large-diameter shaft portion 12. Therefore, the large-diameter shaft portion 12 is subjected to a large load such as the tension of the belt acting on the pulley 8 and the weight of the cooling fan. For this reason, the large-diameter shaft portion 12 must be solid and have a large diameter to ensure sufficient rigidity.

  On the other hand, the small diameter shaft portion 11 provides the mechanical seal 10 between the outer peripheral surface and the inner peripheral surface of the housing 1 and fixes the impeller 9 to the inner end portion. Accordingly, the load applied to the small-diameter shaft portion 11 is limited to the resistance force that the impeller 9 receives when circulating the cooling water, the sliding resistance of the mechanical seal 10, and the like. Small compared to the load applied. For this reason, the small-diameter shaft portion 11 does not need to be so rigid. Therefore, the outer diameter of the small-diameter shaft portion 11 is made sufficiently smaller than the outer diameter of the large-diameter shaft portion 12 in order to reduce the weight while ensuring the required strength and rigidity. , 12 is provided with a stepped portion 13.

  Conventionally, the rotary shaft 3 constituting the water pump as described above is generally formed by subjecting a cylindrical material having an outer diameter equal to or larger than the outer diameter of the large-diameter shaft portion 12 to a turning process. It was. For this reason, not only the time required for processing the rotating shaft 3 is lengthened, but also the yield of the material is poor, and it is inevitable that the manufacturing cost of the rotating shaft 3 is increased. It may be possible to improve the material yield and shorten the processing time by performing some processing by plastic processing such as forging, but do not fully consider the surplus of waste caused by plastic processing. As long as a significant portion is cut by cutting, the manufacturing cost cannot be kept low enough.

JP-A-9-222122 JP 2002-115548 A

  In view of the circumstances as described above, the present invention has been invented to realize a method for manufacturing a rotary shaft for a water pump that can sufficiently reduce manufacturing costs by improving material yield and shortening processing time. Is.

In the method for manufacturing a rotary shaft for a water pump according to the present invention, first, a cylindrical material made of a metal material is plastically deformed cold.
And it is set as the stepped cylindrical shape which provided the step part between the axial direction edge part of the small diameter shaft part, and the axial direction edge part of the large diameter shaft part, and the end surface outer periphery part by the side of the large diameter shaft part of these A chamfered portion is formed on each of the outer peripheral surfaces of the large-diameter shaft portion, and protruding portions protruding outward in the radial direction by collecting surplus metal material are formed as intermediate materials.
After that, the outer diameter of the large-diameter shaft portion is made uniform by subjecting the intermediate material to a cold working process that crushes the protruding portion.

More specifically, in order to carry out the present invention as described above, as described in claim 2, first, a small-diameter shaft portion and a large-diameter shaft are obtained by a forward extrusion process in which the material is plastically deformed cold. A stepped cylindrical preliminary intermediate material in which the part is made continuous by the inclined step part.
Thereafter, the preliminary intermediate material is subjected to an upsetting process in which the large-diameter shaft portion is pressed in the cold direction while only a part of the outer peripheral surface of the large-diameter shaft portion is not restrained in the axial direction. As a result, the inclination angle of the inclined stepped portion is adjusted to be a stepped portion, the surplus is collected on a part of the outer peripheral surface of the large-diameter shaft portion, and the protruding portion is formed on this portion to be the intermediate material. .

When carrying out the invention described in claim 2 as described above, for example, as described in claim 3, before subjecting the material to forward extrusion, chamfering is performed on the outer peripheral edge of the end surface on the large-diameter shaft portion side. Forming part.
Alternatively, as described in claim 4, when the preliminary intermediate material is subjected to upsetting to obtain an intermediate material, a chamfered portion is formed on the outer peripheral edge of the end surface on the large-diameter shaft portion side.

In carrying out the present invention as described above, preferably, as described in claim 5, after the handling, the rotating shaft is supported on a part of the outer peripheral surface of the large-diameter shaft portion. An inner ring raceway for the rolling bearing is formed by cutting. And the part which remove | deviated from this inner ring | wheel track | truck among this outer peripheral surface is not cut.
Alternatively, as described in claim 6, after the handling process, the outer peripheral surface of the small-diameter shaft portion, the tip surface, and the surface of the stepped portion are subjected to cutting for improving the accuracy of these surfaces.

  According to the method for manufacturing a rotary shaft for a water pump configured as described above, the manufacturing cost can be sufficiently reduced by improving the material yield and shortening the processing time.

  1 to 4 show a first example of an embodiment of the present invention. In the case of this example, as shown in FIG. 1, the second material 14 shown in FIG. 1A is replaced with the preliminary intermediate material 15 shown in FIG. 1B by a multi-stage former, which is a kind of cold forging device. Then, the intermediate material 16 shown in (C) is processed into a second intermediate material 17 shown in (D). In addition, these series of processes are all performed cold.

  First, a correction process shown in FIG. 1A is performed on a columnar material obtained by cutting a long material into a predetermined length. In this straightening process, this material is sandwiched between a pair of upper and lower straightening dies 18a, 18b and pressed in the axial direction to remove the distortion of the end face and outer peripheral surface of this material, and the second material 14 And In the example shown in the drawing, in the axial direction both ends of the second material 14, the small diameter shaft portion 11 {refer to (B) to (D) in FIG. 1 and FIG. 4) on the end surface outer diameter portion on the side to be the side, A convex curved surface portion 19 having a relatively large curvature radius is formed. At the same time, a chamfered portion 20 having a quarter-arc-shaped cross section is formed on the outer peripheral edge portion of the end surface on the side that should be the large-diameter shaft portion 12 {see FIGS. 1 (B) to (D) and FIG. 4}. . When the second material 14 is formed in such a correction process, both the correction dies 18a and 18b are released, and the second material 14 is pushed out of the both correction dies 18a and 18b by the knockout pins 21a and 21b. , And sent to the forward extrusion process shown in FIG.

  In the forward extrusion process, the second material 14 is pushed into the forming hole 23 of the extrusion die 22 by the punch 24, and the second material 14 is plastically deformed according to the shape of the inner peripheral surface of the forming hole 23. The preliminary intermediate material 15 is used. The preliminary intermediate material 15 has a stepped cylindrical shape in which the small-diameter shaft portion 11 and the large-diameter shaft portion 12 are made continuous by the inclined step portion 25. Such a preliminary intermediate material 15 is lifted from the punch 24 and then taken out from the forming hole 23 by a knockout pin 26 provided on the extrusion die 22, and the upsetting process shown in FIG. Send to process.

  In this upsetting process, the preliminary intermediate material 15 is sandwiched between a pair of upper and lower upset dies 27a, 27b and pressed strongly in the axial direction, and the inner shape of both upset dies 27a, 27b is changed. The intermediate material 16 is transferred to the preliminary intermediate material 15. In such an upsetting process, the inclined step portion 25 of the preliminary intermediate material 15 is crushed in the axial direction to form a step portion 13 that exists in a direction perpendicular to the central axis. Further, the chamfered portion 20 at the outer peripheral edge portion of the end surface of the large-diameter shaft portion 12 is also pressed again to adjust the shape. In the upsetting process in which such processing is performed, the tip surfaces of the upsetting dies 27a and 27b do not come into contact with each other. There is a gap 28 between them. That is, this upsetting process is performed in a state where only a part of the outer peripheral surface of the large-diameter shaft portion 12 in the axial direction is not restrained. For this reason, as shown in detail in FIG. 2, the surplus generated by processing the inclined step portion 25 into the step portion 13 swells in the radial direction at the gap 28 portion, and the annular protrusion 29 is formed. Form. If the intermediate material 16 is formed in such upsetting process, the both upsetting dies 27a and 27b are released, and the intermediate material 16 is removed from the upsetting dies 27a and 27b by knockout pins 30a and 30b. Extruded and sent to the handling process shown in FIG.

  In this handling process, the intermediate material 16 is pushed into the handling hole 32 of the handling die 31 by the punch 33. As shown in detail in FIG. 3, an annular convex portion 34 that is continuous with the inner peripheral surface main body portion of the handling hole 32 and the inclined surface is formed in the middle portion of the handling hole 32. The protruding portion 29 existing on the outer peripheral surface of the large-diameter shaft portion 12 of the intermediate material 16 is crushed (handled) by passing through the inside of the annular convex portion 34, and the large-diameter shaft portion 12. The outer diameter of the second intermediate material 17 becomes uniform. The second intermediate material 17 is raised from the handling hole 32 by the knockout pin 35 provided on the handling die 31 after the punch 33 is lifted, and sent to the finishing process.

  In this finishing process, cutting is performed on the part indicated by the broken line in FIG. Further, after the necessary heat treatment, this part and the outer peripheral surface of the large diameter portion 12 are ground to complete the rotary shaft 3 for the water pump. That is, in the finishing process, an inner ring raceway 36 for the ball bearing 4 (see FIG. 6) for supporting the rotating shaft is formed on a part of the outer peripheral surface of the large-diameter shaft portion 12 by cutting. A portion of the outer peripheral surface of the large-diameter shaft portion 12 that is off the inner ring raceway 36 is not cut. Further, the outer peripheral surface and the front end surface of the small-diameter shaft portion 11 and the surface of the step portion are subjected to cutting for improving the accuracy of these surfaces. However, this cutting process may be omitted, and the outer peripheral surface, the tip surface, and the stepped surface of the small-diameter shaft portion 11 may be subjected to heat treatment and grinding immediately after the handling process.

Sectional drawing which shows one example of embodiment of this invention in order of a process. The X section enlarged view of (C) of FIG. The Y section enlarged view of (D) of FIG. The side view of the rotating shaft for water pumps after completion. Sectional drawing which shows one example of the structure of a water pump. Sectional drawing which takes out and shows only the rotation support apparatus part of a water pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Mounting flange 3 Rotating shaft 4 Ball bearing 5 Roller bearing 6 Rolling bearing unit 7 Seal ring 8 Pulley 9 Impeller 10 Mechanical seal 11 Small diameter shaft part 12 Large diameter shaft part 13 Step part 14 Second material 15 Preliminary intermediate material 16 Intermediate Material 17 Second intermediate material 18a, 18b Straightening die 19 Convex curved surface portion 20 Chamfered portion 21a, 21b Knockout pin 22 Extrusion die 23 Molding hole 24 Punch 25 Inclined step portion 26 Knockout pin 27a, 27b Upset die 28 Clearance 29 Projection Part 30a, 30b Knockout pin 31 Handling die 32 Handling hole 33 Punch 34 Annular convex part 35 Knockout pin 36 Inner ring track

Claims (6)

  A cylindrical material made of a metal material is plastically deformed in the cold, thereby providing a stepped cylindrical shape having a step portion between the axial end portion of the small diameter shaft portion and the axial end portion of the large diameter shaft portion. In addition, a chamfered portion is formed on the outer peripheral edge of the end surface on the large-diameter shaft portion, and a surplus portion of the metal material is collected on a part of the outer peripheral surface of the large-diameter shaft portion to protrude radially outward. A water pump that equalizes the outer diameter of the large-diameter shaft portion by forming a strip portion as an intermediate material, and then subjecting the intermediate material to a cold processing to crush the projection portion in the cold. Manufacturing method for rotary shaft.   After forming the stepped cylindrical preliminary intermediate material in which the small diameter shaft portion and the large diameter shaft portion are continued by the inclined step portion by forward extrusion processing in which the material is plastically deformed cold, the above large intermediate material is added to the preliminary intermediate material. The inclination angle of the inclined stepped portion is obtained by performing an upsetting process in which the large-diameter shaft portion is pressed in the cold direction while only a part of the outer peripheral surface of the radial shaft portion is not restrained. The manufacturing method of the rotating shaft for water pumps of Claim 1 which makes a step part, collects surplus in a part of outer peripheral surface of the said large diameter shaft part, and makes it an intermediate material which has a protrusion part.   The manufacturing method of the rotating shaft for water pumps of Claim 2 which forms a chamfering part in the outer-periphery edge part of the end surface by the side of a large diameter shaft part before performing a front extrusion process to a raw material.   The manufacturing method of the rotating shaft for water pumps of Claim 2 which forms a chamfering part in the outer-periphery edge part of the end surface by the side of a large diameter shaft, when setting up an intermediate material by carrying out upsetting to a preliminary | backup intermediate material.   After handling, an inner ring raceway for a rolling bearing for supporting the rotating shaft is formed by cutting on a part of the outer peripheral surface of the large-diameter shaft portion, and a portion of this outer peripheral surface that is separated from this inner ring raceway The manufacturing method of the rotating shaft for water pumps as described in any one of Claims 1-4 which do not perform cutting.   The processing according to any one of claims 1 to 5, wherein after the handling process, the outer peripheral surface and the front end surface of the small-diameter shaft portion and the surface of the step portion are subjected to cutting for improving the accuracy of each surface. The manufacturing method of the rotating shaft for water pumps described.

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