JP2010082728A - Method and device of manufacturing crankshaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance rotation balance accuracy while suppressing an unbalance amount to be corrected to the minimum at an inspection step after machining when a crankshaft, especially a 3-cylinder crankshaft is manufactured. <P>SOLUTION: In the method for manufacturing the crankshaft, positioning of a center hole becoming machining reference when mechanical machining is performed relative to a shaped material of the crankshaft molded by forging is performed. In a centering step of forming the center hole on the shaped material, first clamp arms 11a, 11b for clamping an end shaft part 101 of the shaped material by approaching to each other on the same linear line and second clamp arms 12a, 12b are provided. The end shaft part 101 is clamped such that a clamp center of the pair of first clamp arms 11a, 11b and a clamp center of the pair of second clamp arms 12a, 12b are coincident with a center of gravity O<SB>G</SB>of an end surface of the end shaft part 101, a center hole is formed at a position corresponding to the clamp center at that time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a crankshaft manufacturing method and manufacturing apparatus, and more particularly to a crankshaft manufacturing method and manufacturing apparatus suitable for manufacturing a forged three-cylinder crankshaft.

  The manufacturing process of the crankshaft is generally composed of a forging process, a centering process, a machining process (mirror surface machining, oil passage drilling, etc.), a finishing process, and an inspection process. In the inspection process, the amount of unbalance (eccentricity) of the crankshaft is measured, and the balance weight provided on the crankshaft is perforated according to the measured degree of unbalance to correct the unbalance. ing.

  However, this type of shaft is formed through forging and various types of machining, and individual processing accuracy tends to vary greatly. Therefore, the unbalanced amount of the actual product may exceed the range assumed in advance, and this is one factor that causes the production line to stop or the yield to decrease.

For example, in Patent Document 1 below, as a means for solving the above-described problem, an unbalanced amount of a forged shape material, in this case, vibration caused by a deviation between the rotation axis of the shape material and the inertia main shaft is described. A weight centering device (mass centering device) that measures the size before the machining process and drills a center hole that serves as a reference in the axial direction of machining is disclosed. Has been. In addition, a method for centering a shaped material using the weight centering device is disclosed.
JP 2000-121479 A

  By the way, the method for eliminating imbalance by the weight centering device disclosed in Patent Document 1 is applicable to, for example, a crankshaft for four cylinders or more, but for a three cylinder used mainly in light vehicles. It cannot be applied to crankshafts. The crankshaft for three cylinders is usually formed through a forging process. In this type of crankshaft, crankpins are arranged at intervals of 120 °, so that for the purpose of ensuring releasability during forging, There is a situation in which the counterweight on the center crankpin side must be set smaller than the counterweight on the crankpin side at both ends. Due to such circumstances, in the three-cylinder crankshaft, counterweights on both ends of the shaft are set considerably heavier (larger) than that for, for example, four cylinders in order to secure an unbalance correction allowance. Therefore, (1) if centering is performed at a position where the unbalance amount becomes zero (inertial spindle position), there is a risk of centering at a position far from the actual center of rotation of the shaped material. This may not function sufficiently as a center hole for machining. Also, (2) the unbalance amount becomes too large by intentionally designing the counterweights at both ends for the above reasons, and the unbalance amount cannot be corrected even if the counterweight is drilled. Cases can arise.

For the above reasons, when manufacturing a three-cylinder crankshaft through forging, a centering device cannot be used, so the center hole is positioned using an appropriate alignment mechanism instead of the centering device. It is carried out. FIG. 6 shows an example of this, and the end shaft portion 101 of the raw material as a portion corresponding to the crank journal that is the rotation main shaft of the crankshaft is clamped by a pair of vises 111 and 112 that can be relatively moved in one axial direction. by a mechanism to adjust the rotational center _{O R} of Tanjiku portion 101 to the center position between devices 111 and 112 are employed. However, the crankshaft shaped material formed by forging is actually formed by using a pair of split dies, and as shown in FIG. 7, the mold alignment mark 101c (parting line mark) A semi-cylindrical upper tube portion 101a and lower tube portion 101b may be formed in a state of being shifted to the left or right, for example (in this figure, the amount of displacement is exaggerated. FIG. Is also exaggerated in the same way.) As described above, when the end shaft portion 101 is displaced from the alignment mark 101c as a boundary, the cross section becomes a non-circular shape, and the clamp mechanism (vice 111, 112) illustrated in FIGS. I can't center it. In this case, the center hole is biased, and as a result, the variation in the unbalance amount in the external shape processing (after machining) also increases.

  In view of the above circumstances, when manufacturing a crankshaft, particularly a three-cylinder crankshaft, it is possible to minimize the amount of unbalance to be corrected in a post-processing inspection process while improving the rotational balance accuracy. It should be a technical issue.

  The present invention has been made to solve the above problems. That is, in the crankshaft manufacturing method according to the present invention, the center hole is positioned as a machining reference when machining the crankshaft shaped material formed by forging, and the center hole is formed into the shaped material. In the crankshaft manufacturing method including at least the centering step to be formed, a plurality of pairs of clamping jigs for clamping the shaped material by approaching each other on the same straight line are provided in the centering step. It is characterized by the fact that the base material is clamped such that the clamp center of the clamping jig coincides with the center of gravity of the cross section of the base material, and a center hole is formed at a position corresponding to the clamp center at this time.

The present invention was made based on the knowledge that the cross-section of the end shaft portion of the forged molded material has a point-symmetric shape centered on the center of gravity, and a plurality of pairs of clamping jigs The base material is clamped so that the center of the clamp coincides with the center of gravity of the cross section of the base material. Here, the clamping mode will be described in detail with reference to FIG. 5. The end shaft portion 101 of the base material is clamped in different directions (two types of arrow directions in FIG. 5) by two pairs of clamping jigs. The Each pair of clamping jigs clamps the end shaft portion 101 by approaching each other on the same straight line. In this case, the cross section of the end shaft portion 101 has a shape shifted to the left and right along the mold alignment mark 101c, and the clamp positions C _1A and C _1B by one clamping jig are on the same straight line. since the clamping position _{C 1A, C 1B} is in the position of point symmetry about the cross-section gravity center _{O G.} Thus, the clamp center of one clamping jig is consistent with the cross-section gravity center O _G. Similarly, the clamping position C _2A by other clamping _jig, C _2B is also in positional relationship of the point object around the cross-section gravity center O _G, clamps around the other clamping jig is consistent with the cross-section gravity center O _G .

  Therefore, according to this configuration, the center hole is positioned simultaneously with the clamping of the end shaft portion, and the center hole can be formed in a reliable and appropriate position. Thereby, the unbalance correction amount (correction allowance) in the inspection process can be minimized. In other words, since the balance weight can be designed to be smaller than before, the material cost and the processing cost can be reduced, and the processing time can be shortened. In addition, the releasability is also improved, leading to improved forging accuracy.

  In this case, specifically, for example, a plurality of pairs of clamp jigs have a common clamp center, and any pair of clamp jigs moves at an equal distance from the common clamp center. Can be configured. By comprising in this way, the said shaping | molding material is clamped, performing a centripetal operation automatically with respect to the shaping | molding material arrange | positioned between several pairs of clamp jigs. Therefore, the center hole can be accurately aligned regardless of variations in the outer shape of the base material. Further, the center hole can be aligned automatically and easily.

  Also, the solution to the above-mentioned problem is that the center hole is positioned as a machining reference when machining the crankshaft shaped material formed by forging, and the center hole is formed in the shaped material. In the crankshaft manufacturing apparatus having at least the means, the centering means corresponds to a pair of clamping jigs that clamp the shaped material by approaching each other on the same straight line, and a clamp center of the clamping jig. Center hole forming means for forming a center hole at a position where a plurality of pairs of clamping jigs are provided, and the plurality of pairs of clamping jigs have cross-sections of the base material of each pair of clamp centers. It is also achieved by a crankshaft manufacturing apparatus that is configured to be able to clamp a shaped member so as to coincide with the center of gravity.

  As described above, according to the present invention, when manufacturing a crankshaft, particularly a three-cylinder crankshaft, the rotational balance accuracy is improved while minimizing the amount of unbalance to be corrected in the inspection process after processing. Can be increased.

  Hereinafter, an embodiment of a crankshaft manufacturing method and manufacturing apparatus according to the present invention will be described with reference to the drawings.

  FIG. 2 shows a perspective view of a crankshaft shaped member 100 according to an embodiment of the present invention. The raw material 100 is formed in the process of manufacturing a crankshaft for a three cylinder, and is formed into a shape according to a finished product by forging. The base material 100 has three crank pins, counter weights arranged on both sides of the pins, and connects between the counter weights, and also has portions corresponding to the crank journals serving as the rotation main shaft in the finished product state. Therefore, the portions (end shaft portions 101, 101) corresponding to the crank journals at both ends are used as a positioning reference for the center hole in the centering process described later. Here, the base material 100 is a forged molded product with upper and lower divided dies, and the end shaft portion 101 has a uniform cross-sectional shape along the axial direction from the end surface.

  FIG. 1 is a perspective view of a crankshaft manufacturing apparatus provided with centering means 10 for clamping one end shaft portion 101 of a shaped member 100 and forming a center hole in the end surface of the end shaft portion 101. The principal part side view of the means 10 is shown. The centering means 10 is configured to be relatively movable on the same straight line, and the first and second clamping means 11 and 12 that clamp the raw material 100 by approaching each other are omitted from illustration. Center hole forming means for forming a center hole at a predetermined position on the end surface of the end shaft portion 101 clamped by both the clamp means 11 and 12 is mainly provided. In addition, although illustration is abbreviate | omitted here, the centering means 10 of the said structure is also arrange | positioned also at the other end shaft part of the raw material 100. FIG.

  The first clamp means 11 is mainly composed of a first clamp arm pair 11a, 11b and a slide rail portion 11c connected to the first clamp arm pair 11a, 11b so as to be relatively slidable. . Although not shown in the drawings, each of the clamp arms 11a and 11b incorporates a motor serving as a drive source, and the motors are driven and controlled by appropriate control means to slide the clamp arms 11a and 11b. The position on the rail portion 11c can be controlled. Further, the clamp arm pairs 11a and 11b are controlled so as to be able to approach or separate at the same speed in synchronization. Here, the workpiece receiving surface at the tip of each clamp arm 11a, 11b is formed into a flat surface aiming at line contact with the outer peripheral surface of the end shaft portion 101. The same applies to the shape of the workpiece receiving surface at the tip of the second clamp arm pair 12a, 12b described later.

  Similar to the first clamp means 11, the second clamp means 12 is a second clamp arm pair 12a, 12b and a slide rail connected to the second clamp arm pair 12a, 12b so as to be slidable relative to each other. It is mainly comprised by the part 12c. In addition, each clamp arm 12a, 12b incorporates a motor as a drive source, and the motor is driven and controlled by, for example, a control means common to the first clamp means 11, whereby each clamp arm 12a is controlled. , 12b on the slide rail portion 12c are controlled in the same manner as the first clamping means 11.

  Here, looking at the positional relationship between the two clamping means 11 and 12, both the slide rail portions 11c and 12c are arranged in directions orthogonal to each other when the centering means 10 is viewed from the side. Thereby, the clamp direction (relative movement direction) of the first clamp arm pair 11a, 11b and the clamp direction (relative movement direction) of the second clamp arm pair 12a, 12b are configured to be orthogonal to each other. In this embodiment, the clamp center of the first clamp arm pair 11a, 11b (in the illustrated example, the intermediate position between the contact surfaces of the clamp arms 11a, 11b with the shaped member 100. Second clamp. The same applies to the arm pair 12a and 12b) and the two clamp arm pairs 11a, 11b, 12a and 12b move in synchronization so that the clamp centers of the second clamp arm pair 12a and 12b are always at the same position. To be controlled.

  Hereinafter, the centering process of the raw material 100 using the centering means 10 according to the above configuration will be described.

  First, in the state shown in FIG. 2, the portion excluding the end shaft portion 101 of the shaped member 100 is rotatably supported by an appropriate support means (not shown), and the end shaft portion 101 is a first clamp arm pair. 11a and 11b and between the second clamp arm pair 12a and 12b. Then, from this state, as shown in FIG. 3, the first clamp arm pair 11a, 11b and the second clamp arm pair 12a, 12b are relatively approached (moved from the solid line position to the one-dot chain line position in FIG. 3). Thus, the end shaft portion 101 is clamped in two different directions.

Simultaneously with this clamping, the end shaft portion 101 is urged by the first and second clamp arm pairs 11a to 12b and moved to a position suitable for forming a center hole described later. Specifically, the end axis at the position where the end surface gravity center O _G (substantially the same position as the cross-sectional center of gravity) of the end shaft portion 101 coincides with the common clamp center of the first and second clamp arm pairs 11a to 12b. Part 101 is clamped. In terms of Figure 3, the first clamping arm pairs 11a, 11b by the clamp position _{C 1A,} intermediate positions _{C 1B} coincides with the end surface center of gravity _{O G} of Tanjiku portion 101, and a second clamping arm pairs 12a, clamping position _C 2A by _12b, Tanjiku portion 101 is clamped so that the middle position of the _{C 2B} coincides with the end surface center of gravity _{O G} of the end shaft portion 101. In this case, the distance between the clamp positions C _1A and C _1B by the first clamp arm pair 11a and 11b is different from the distance between the clamp positions C _2A and C _2B by the second clamp arm pair 12a and 12b.

  Therefore, in this state, a center hole forming means (in a position corresponding to the common clamp center of the first and second clamp arm pairs 11a to 12b whose position is controlled by an appropriate control means on the end face of the end shaft portion 101 is provided. The center hole is automatically positioned at the same time as the end shaft 101 is clamped.

Thus, according to the above clamping method, the upper tube portion 101a and the lower tube portion 101b of the end shaft portion 101 have a shape shifted to the left and right with respect to the mold alignment mark 101c generated during forging. centroid distance from (sectional center of gravity) O _G to the outer peripheral surface arbitrary position even when nonuniform machining (black Peel machining, etc. specular processing) in step that follows while performing positioning of the center hole suitable for It becomes possible to clamp the end shaft portion 101 (original material 100) at a position where the amount of unbalance to be corrected in the inspection process after the processing can be minimized. At this time, in order to perform clamping with more accurate positioning, the clamp positions C _1A and C _1B of the end shaft portion 101 by the first clamp arm pair 11a and 11b are out of the alignment mark 101c. It is good to do. Similarly, for the second clamp arm pair 12a and 12b, the clamp positions C _2A and C _2B are preferably set at positions that are out of the alignment mark 101c.

  As mentioned above, although the manufacturing method of the crankshaft which concerns on one Embodiment of this invention was demonstrated, of course, this invention is not limited to the said form, It is also possible to take another form. Examples are introduced below.

  In the above embodiment, the case has been described in which the shape material 100 is clamped when the end surface of the end shaft portion 101 has a surface shape shifted to the left and right along the mold alignment mark 101c. The present invention can also be applied to other end face shapes resulting from the forging form. FIG. 4 shows an example, and the end shaft portion 201 of the base material shown in FIG. 4 is divided into an upper cylindrical portion 201a and a lower cylindrical portion 201b which are divided into upper and lower portions with a matching mark 201c as a boundary. It has an end face (cross section) shape that is displaced in the direction. In other words, the alignment mark 201c has an end surface shape having a predetermined width in the vertical direction. In this case, the shaped member (the end shaft portion 201) is clamped as follows using the centering means 10 shown in FIG.

  That is, as shown in FIG. 4, the first clamp arm pair 11a, 11b and the second clamp arm pair 12a, 12b are moved relatively close to each other (moved from the solid line position in FIG. The shaft part 201 is clamped in two different directions.

Simultaneously with this clamping, the end shaft portion 201 is urged by the first and second clamp arm pairs 11a to 12b and moved to a position suitable for forming a center hole described later. Specifically, the end surface center of gravity O _G of Tanjiku portion 201, an end shaft portion 201 is clamped in a position coinciding with a common clamping center of the first and second clamping arm pairs 11A～12b. In terms of FIG. 4, the first clamp arm pairs 11a, 11b by the clamp position _{C 1A,} an intermediate position between the _{C 1B} coincides with the end surface center of gravity _{O G} of Tanjiku portion 201, and a second clamping arm pairs 12a , clamping position _C 2A by _12b, Tanjiku unit 201 as the intermediate position between the _{C 2B} coincides with the end surface center of gravity _{O G} of the end shaft portion 201 is clamped.

  Therefore, in this state, the center hole forming means (in the position corresponding to the common clamp center of the first and second clamp arm pairs 11a to 12b whose position is controlled by an appropriate control means on the end face of the end shaft portion 201 is provided. The center hole is automatically positioned at the same time as the end shaft 201 is clamped.

As described above, according to the clamping method, the center hole can be properly positioned regardless of the misalignment shape with the alignment marks 101c and 201c of the end shaft portions 101 and 201 as the boundary, and the processing is performed. The end shaft portions 101 and 201 can be clamped at a position where the amount of unbalance to be corrected in the subsequent inspection process can be minimized. Further, when the clamp, even if the end surface center of gravity O _G is placed with a shift in the vertical and horizontal any direction from the clamp center, the automatic centripetal action, both of the clamping arm pairs the end surface center of gravity O _G The end shaft portions 101 and 201 can be clamped at a position coinciding with the shared clamp center of 11a to 12b.

In any of the above embodiments, the clamping direction of the first clamp arm pair 11a, 11b and the clamping direction of the second clamp arm pair 12a, 12b (for example, the direction indicated by the broken line in FIGS. 3 and 4) Although the case where both the clamp means 11 and 12 are arrange | positioned so that it may mutually orthogonally cross was illustrated, it does not necessarily need to orthogonally cross. End face centroid (sectional centroid) _{O G} and each clamp arm pair 11a, 11b, 12a, the crossing angle as long as the clamping center of 12b coincide all of which are optional. In FIG. 3, for example, a line segment _O G _{-C 2A} and the line segment _O G _{-C 1A} and is an angle is acute, the line segment _O G _{-C 1B} and the line segment _O G _{-C 2A} and the angle formed obtuse Both clamping means 11 and 12 may be arranged so that

  The number of clamping jigs (clamp arms) need not be two. For example, the end shaft portion may be clamped by three or more clamping jigs (clamp arms).

  In the above embodiment, the first clamp arm pair 11a and 11b and the second clamp arm pair 12a and 12b are controlled to move in synchronization with each other at an equal distance from the common clamp center. Although demonstrated, the operation | movement aspect of these clamp arms 11a-12b is not restricted to this. The positional relationship between the end shaft portions 101 and 201 only needs to be the positional relationship shown in FIGS. 3 and 4 in the final clamped state, for example, and the four clamp arms 11a to 12b are sequentially moved at an appropriate timing. You may control to do. Alternatively, one of the four clamp arms 11a to 12b may be fixed and the remaining three may be controlled to move.

  In addition, regarding the driving means of each clamp arm 11a to 12b, the driving means such as a motor is provided integrally with each of the clamp arms 11a to 12b, and for example, a place on the fixed side with respect to the clamp arms 11a to 12b (in FIG. For example, it may be arranged on the slide rail portions 11c and 12c). Alternatively, the configuration itself relating to the combination of the clamp arms 11a to 12b and the slide rail portions 11c and 12c may be changed. For example, each clamp arm pair 11a, 11b, 12a, 12b can be configured to be relatively movable on the same straight line by using a rack and pinion mechanism. Or each clamp arm 11a-12b is connected with a cylinder mechanism, and you may make it arrange | position so that each clamp arm pair 11a, 11b, 12a, 12b can respectively move on the same straight line.

  Further, in the above description, the case where the shape material of the crankshaft for three cylinders is targeted for centering is exemplified, but the present invention is based on the technical content of the shape material for crankshafts for four cylinders or more. Of course, it can also be applied to the centering process.

  Of course, the present invention other than the above can take other specific forms within the scope of the present invention.

It is a principal part side view of the centering means of the shaping | molding material which concerns on one Embodiment of this invention. It is a perspective view of the shape material of the crankshaft which concerns on one form. It is a side view which illustrates conceptually the centering process of a preform. It is a side view which illustrates notionally the centering process of the raw material of the crankshaft which concerns on another form. It is principal part sectional drawing of the basic shape material which illustrates the centering process which concerns on this invention conceptually. It is principal part sectional drawing of the basic shape material which illustrates the conventional centering process conceptually. It is principal part sectional drawing of the basic shape material which illustrates the conventional centering process conceptually.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Centering means 11 1st clamp means 11a, 11b 1st clamp arm pair 11c Slide rail part 12 2nd clamp means 12a, 12b 2nd clamp arm pair 12c Slide rail part 100 Shape material 101, 201 end shaft portion 101c, 201c type seam marks 111 and 112 devices _{C 1A, C 1B} first clamping position _C 2A by the clamp _{means, C 2B} second clamping position _{O G} end surface center of gravity by the clamp means (section centroid)
O _R rotation center

Claims (3)

A crankshaft including at least a centering step for positioning a center hole that is a processing reference when machining a crankshaft shaped material formed by forging, and forming the center hole in the shaped material. In the manufacturing method of
In the centering step, a plurality of a pair of clamping jigs for clamping the raw material by approaching each other on the same straight line,
Clamp the shaped material so that the clamp centers of the plurality of pairs of clamping jigs all coincide with the cross-sectional center of gravity of the shaped material, and form a center hole at a position corresponding to the clamp center at this time A method of manufacturing a crankshaft characterized by the above.   The plurality of pairs of clamp jigs have a common clamp center, and any of the pair of clamp jigs is configured to move at an equal distance from the common clamp center. The manufacturing method of the crankshaft described in 2. A crank provided with at least centering means for positioning a center hole as a processing reference when machining a crankshaft shaped material formed by forging and forming the center hole in the shaped material. In shaft manufacturing equipment,
The centering means forms a center hole at a position corresponding to a clamp center of the clamp jig and a pair of clamp jigs for clamping the shaped material by approaching each other on the same straight line. Center hole forming means,
A plurality of the pair of clamping jigs are provided, and the plurality of pairs of clamping jigs can clamp the raw material so that each pair of clamp centers coincides with the cross-sectional center of gravity of the raw material. It is comprised in the crankshaft manufacturing apparatus characterized by the above-mentioned.

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