JPS6120643A - Formation of rough forging for crank throw - Google Patents

Abstract

PURPOSE:To improve the dimension accuracy and productivity by forging simultaneously a forming surface for controlling a length of head part, and both front and rear sides through a roughly triangular wall-shaped projection, and also forming the head part by recessing and providing a notch on the center lower part and the bottom face. CONSTITUTION:A forging tool 22 of the lower position is provided on a receiving surface 21b of a receiving base 21 fixed to a bed or a floor surface, and also the forging tool 22 of the upper position is made to contact along a vertical guide surface 21a and charged. In this state, the forging tool 22 of the upper position is put by a tool manipulator 32 and a base material of an oblique line part is forged and worked. The tool 22 controls a height and a length of the head part as required and executes forging through pressure of a press by a forming surface 22a. Also, a triangular wall-shaped projection 22 provided in the center of the forming surface 22a forms a triangular groove-shaped notch. Accorcing to this method, the dimension accuracy of a throw material is improved, and also the productivity is improved.

Description

[Detailed Description of the Invention] <Field of Industrial Technology> The present invention relates to a crank throw in which a pin shaft and a pair of arms are integrally formed, and in particular, in obtaining the crank throw by forging from a steel ingot, the pressing and bending process is performed. This invention relates to an improved forging process for the shape of a head when forming a forged rough material before processing, so that a head with excellent dimensional accuracy and reduced excess thickness can be efficiently obtained.

<Prior Art> Obtaining a crank throw by forging a steel ingot belongs to a known technique as a press-bending method for crank throws.

FIGS. 1A to 1N illustrate the details of this technology, and as shown in FIGS. 1A, a columnar steel ingot 1 is used as a forming material,
As shown continuously in A, B, and C of the same figure, the upper and lower flat anvils 2 and 2 are used to forge and elongate the plate material 3 with a rectangular cross section. The figure shows the case of obtaining two forged blanks for crank throws from a shaped material 3. As shown in the figure, the material 3 is cut into a predetermined position using an arrow head 4 and a flat anvil 2. Both longitudinal sides 3a
・By forging the corresponding part of 3a to form both the front and rear side surfaces 5a, 5a, which are approximately tapered inclined surfaces, the material 3 (
7)'The top surface 3b is the top surface 5b, and the bottom surface 3C of the material 3
is the bottom surface 5C, and both sides in the axial direction (longitudinal direction) are the material 3
The head 5 (later to become the pin shaft portion of the crank throw) is defined by the head 5, which is shown in FIG. The material 3 other than the head 5 is the part that will later become the arm of the crank throw. After defining the head 5 on the material 3 in this way, as shown in FIG.
In order to separate the part that will later become the arm, on the upper surface 3b side of the material 3, use a back cutting tool 6 to cut both sides of the head 5 in the axial direction, that is, at the boundary position of the part that will become the arm.
is a base anvil used in correspondence with the back cutting metal fitting 6.

As shown in FIG. It is formed by forging. - In this case, since the material 3 is shaped to remove two crank throws, as shown in Figure I, the material 3 is removed from the plate piece 8 using a shaping dividing tool 9 commonly called a chimney. The dividing grooves 10 are formed by processing the side surfaces 8a and 8a into approximately circular curved surfaces using the longitudinal side surfaces 3a and 3a as they are, and by cutting from the dividing grooves 10, As shown in FIG. 2, a rough material for pressing and bending 11 is obtained in which the plate pieces 8 are integrally continuous on both the left and right sides of the head 5 mentioned above. Forged wasteland 1 obtained in this way
1 is supported in a cross-shaped manner on a bridge-shaped receiving tool 12, as shown in FIG. Then, as shown in the same figure and M, the rough ground 11 that has been pressed and bent into a V-shape is further inserted into the upper and lower flat anvils 14 and 15, and the guide and dowel that are inserted into the pressed and bent inside of the V-shape. 16
Finally, the outer shape of the head 5 is shaped by the base anvil 17 and the flat anvil 1B as shown in FIG. Through machining, the head 5 is formed into a desired pin shaft, and the pair of plate pieces 8 are formed into a pair of arms extending parallel to each other at both ends of the pin shaft, resulting in a crank throw product.

<Problems to be Solved by the Invention> In the above-mentioned prior art, there are the following problems regarding the forged rough ground 11. That is, the forging of the head 5 (the part that will later become the pin shaft) on the rough ground 11 was carried out in the 1111th
As explained in A-N Glue and E, both sides 3a and 3a of the material 3 in the longitudinal direction are attached using the observatory 4 and the flat anvil 2.
The corresponding part of 3a is forged into a tapered shape to form both front and rear sides 5a.
・The head portion 5 is formed by forming the portion 5a into a concave shape. This forging process is performed as shown in FIG. 2, 1H. As shown in ■ in the same figure, the observatory 4 has the bottom surface 3C of the material 3 on its top surface.
The receiving surface 4a that supports the support surface 4a and the receiving surface 4b that supports one of the both side surfaces 3a and 3a have supporting surfaces formed orthogonally, and the bottom surface 3c of the material 3 is attached to the receiving surface 4a and One side surface 3a is supported on the receiving surface 4b, the remaining side surface 3a faces upward, and the side surface 3a is forged with the flat anvil 2, leaving a part of the side surface 3a and forming the front surface 5a of the head 5. After forming, the direction of the observatory 4 is changed as shown in Fig. 2 (■), so that the already formed front side 5a faces the receiving surface 4b, the bottom surface 3c is covered with the receiving surface 4b, and the other side 3a is made to face the receiving surface 4b. On the other hand, similarly, the flat anvil 2 is used to press-form the rear side surface 5a, so that a part of the bottom surface 3c of the material 3 is formed into a bottom surface 5c on a predetermined part of the material 3, and a part of the top surface 3b of the material 3 is made into a bottom surface 5c. A substantially trapezoidal head 5 is formed by forging, with the upper surface 5b being the upper surface 5b and the front and rear side surfaces 5a and 5a being formed into a tapered shape. No special processing is performed. In the head 5, first, in the forging process, both the front and rear sides 5a and 5a are machined one by one, so the handling operation is complicated, such as reversing the observatory 4, changing the material 3, and the necessity of two steps increases the forming time. The problem is that it takes time. Since this head 5 is the part that will later become the pin shaft, it is necessary to give sufficient consideration to its shape and dimensional accuracy. However, in the conventional forging process using the flat anvil 2, the required head height and length Therefore, when pressing and bending the plate pieces 8, 8 on the rough ground 11 to obtain the crank throw material 9, the following inconvenience occurs. In Fig. 3 (■) and (H), the dimensional accuracy at the boundary parts A and B between the front and rear side surfaces 5a and 5a of the forged-formed rough ground 11 and the plate pieces 8 and 8 that are continuous on the left and right sides thereof is unclear, and the front and rear side surfaces 5a and 5A are unclear. Because the shape of 5a is inappropriate, the structure surrounded by D"-N-C' and K'-P-M' is This results in a large amount of excess material, which is extremely disadvantageous in terms of material yield.

Means for Solving the Problems> The present invention involves forging the plate-shaped material 3 as described above to forge the head 5 and the press-bending rough ground 11 formed by the pair of plate pieces 8 connected to the left and right of the head 5. In order to solve the technical problems that arise especially in the forging process of the head part 5 when forming the head part 5, the objective is to provide a technical means including a new forging process content of the head part 5, and such technical means are as follows: A square material with a quadrilateral cross section is used, and a head part that will later become the pin shaft, and a continuous part at both ends of the head part in the pin shaft axis direction are used.
In a method for forging and forming a crank throw rough material consisting of a pair of plate pieces that will later become an arm,
When forming the head, the bottom surface of the head was supported on a vertical guide surface, and the height and length of the head with a pair of upper and lower forging tools were regulated as required on both front and rear sides following the bottom surface. Through the molding surface and a roughly triangular wall-shaped protrusion provided at the lower center of the molding surface, both the front and rear sides are forged at the same time, forming a roughly trapezoidal shape, and extending over the lower center of the front and rear sides as well as the bottom surface. The object of the present invention is to obtain a head in which a substantially triangular groove-shaped notch is recessed.

<Operation> The above technical means functions as follows. In FIG. 4 I, in the present invention, when forging the head 5 on a required part of the plate-shaped material 3 (corresponding to the processing step shown in FIG. 1, E), the head 5 should be formed. The bottom surface 30 portion of the material 3 is supported on the vertical guide surface 21a, and the front and rear side surfaces 3a and 38 portions of the material 3 following the bottom surface 3c are held between a pair of upper and lower forging tools 22, and the tools 22・A molding surface 22a in which the height and length of the head 5 are preliminarily regulated at 22. ・A vertical guide surface 21a and a pair of upper and lower tools 22 that intersect with the vertical guide surface 21a are formed by forging using press pressure using 22a.・A part of the material 3 restrained by 22 is forged through the deformation of the upper surface 5b of the material 3 that is freed, and the desired front and rear sides 3a, 3a are forged to form a front and rear with an accurate shape and dimensional accuracy. It is possible to form a substantially trapezoidal head 5 with the side surfaces 5a, 5a, the bottom surface 3C regulated by the vertical guide surface 21a being the bottom surface 5C, and the top surface 3b being the top surface 5b.

Furthermore, in the present invention, a triangular wall-shaped protrusion 22b is provided in advance at the center of the molding surface 22a and at the lower part in the head height direction, so that both front and rear side surfaces 5a and 5 on which the protrusion 22b is molded are formed.
By being press-fitted into the central lower part of a at the same time as the forging process, from the central lower part of both front and rear sides to the bottom surface 5c,
A notch 5d in the shape of a triangular groove is formed, and by using the pair of upper and lower forging tools 22, the head 5 can be easily obtained in step (2).

The vertical guide surface 21a shown in FIG.
This can be easily obtained by using the pedestal 21 shown in FIG. That is, as shown in FIG. 4H, a sturdy L-shaped pedestal 21
By forming a wall-shaped guide surface 21a perpendicular to the inner surface of one side and forming a receiving surface 21b perpendicular to the vertical guide surface 21a, one of the pair of upper and lower forging tools 22 is placed on the upper end of the vertical guide surface 21a. By forming the locking groove 21c for the upper tool 22 and the locking groove 21d for the lower tool 22 on the receiving surface 21b, these tools 22 shown in FIG.
・22, the combination of the pedestal 21 is obtained, and stable forging processing can be obtained uniformly. As is clear from FIG. 4 ■ and H, the locking groove 21c is located on the tool 22 side
- By forming the locking portions 22c that can be freely engaged and detached from the tool 21d, the tools 22 are securely fixed. The pair of upper and lower forging tools 22, 22, as shown in FIG. To explain the forming surface 22a and protrusion 22b of the lower tool 22 shown in , the forming surface 22a is the vertical guide surface 2.
A bottom side 23 joining to 1a and an upper side 24 parallel to this,
It has a shape in which both ends of the top side 24 and the bottom side 23 are connected and surrounded by mutually parallel sides 25.
・By making 25 into a tapered shape, the molding surface 22a
is inclined from the top side 24 toward the bottom side 23. At this time, the length Ll of the side edge 25 that determines the height of the head 5 is determined by the crank throw material 19 shown in FIG.
A pair of plate pieces 8, 8 are pressed and bent on both sides of the head 5, indicated by M), and the length is slightly larger than the diameter of the pin shaft 30 that will be obtained later by cutting. The length L2 of the upper side 24 that determines the length of 5 is:
Similarly, the length between the outer surfaces of the pair of plate pieces 8 and 8 shown in FIG. 5 is made slightly smaller than the length in the arm (lt). Further, the triangular wall-shaped protrusion 22b includes a straight wall 26 that stands vertically in series with the bottom side 23, a slanted wall 27 that ends from the upper end of the straight wall 26 to approximately the center of the molding surface 22a, and both walls 26.
27 is surrounded by both side walls 28, 28 which are connected, and each side wall 28, 28 has a cutout taper,
The width L3 of the straight wall 26 (width of the notch 5d) is equal to the inner surface spacing 12 between the pair of arms 31, which will be obtained later by cutting, on both the plate pieces 8, 8 shown in FIG.
The width is considered to be slightly smaller than that of the original. By forging both the front and rear side surfaces 5a and 5a of the head 5 using the molding surface 22a and the protrusion 22b whose shape and dimensions are regulated in this way, it is possible to easily obtain a head 5 with an appropriate shape and dimensional accuracy. Therefore, instead of the steps D and E in FIGS. 1A-N shown in the prior art, after the head 5 is forged using the pedestal 21 and forging tools 22 and 22 of the present invention. , when obtaining the forged rough ground 11 by forging the plate pieces 8 and 8 shown in F and I below in FIG. 1A-N,
As shown in FIG. 6, the rough ground 11 according to the present invention is such that the head 5 is maintained in a well-defined shape and size, and the plate pieces 8 and 8 are
The dimensional accuracy of the boundary part is also improved, and by appropriately regulating the dimensions of both the front and rear sides 5a, 5a, the plate pieces 8 and
When the crank throw material 19 is obtained by bending the crankshaft 8, it is possible to reduce the excess thickness and improve the material yield. The reason for this is as follows. In the present invention, a triangular wall-shaped protrusion 22b is formed at the center of the molding surface 22a in the length direction of the head and in the lower half of the head in the height direction. At the bottom center of
The formation of the triangular groove-shaped notch 5d as shown in the figure was achieved by comparing the results when there is no groove on the front side surfaces 5a and 5a and when the groove shape is different, as shown in FIGS. 7A, B, and C. This is because, as a result of experiments, it was found that the shape of the notch 5d according to the present invention is the most appropriate, and four types of patterns are shown in FIG. 7A. That is, as shown in Figure A-1, the front and rear sides 5
A with no notch at all, one with a triangular groove-shaped notch 5d according to the present invention shown in Figure A-2, and one with a tapered triangular groove-shaped notch 5d as shown in Figure A-3. As shown in Fig. A-4, the cutout 5d has a wide angle groove shape.

Figure 7B shows the deformed state of the pot when the left and right plate pieces 8, 8 are pressed and bent for these four types of patterns, and the one shown in Figure B-1 is shown in Figure 7B. The pattern of A-1 in A, the one shown in Figure B-2 is the pattern of Figure 7 A-2, and the one shown in Figure B-3 is the pattern of Figure 7 C-1. The pattern shown in FIG. B-4 is the pattern shown in FIG. 7 C-1, and both are front views. On the other hand, what is shown in Fig. 7C is a side sectional view taken from line B-B of each figure in Fig. 7B, and Fig. 7C-1 is a side sectional view of the one shown in Fig. 7C-1. The one shown in Figure C-2 is a side sectional view of the one shown in Figure 7 B-2, and the one shown in Figure C-3 is a side sectional view of the one shown in Figure 7 B-2 and B-2. It is a side sectional view of the thing shown in -3. To the symbols illustrated in FIGS. 7B and C
"" indicates corresponding portions (positions), and looking at the results of these four types of patterns, the shape of the notch 5d according to the present invention shown in FIG. 7A-2 is the best.

That is, in the pattern A-1 which does not have a notch shown in FIG. 7A, there is no problem when the amount of excess metal is large as shown in B-1 of FIG. 7B and C-1 of FIG. 7C. . On the other hand, the notch 5d according to the present invention, that is, A- in FIG.
2 pattern is B-2 in Figure 7 B and C,
As shown in 'C-2, even if the illustrated F"E'-1'J" is located outside the arm 31 indicated by the broken line, it can be modified later, whereas G'-)1' can be modified later. However, with the notch 5d of the present invention, the G'' and H'' do not protrude outside the arm 31, so the amount of excess metal is reduced and there is no risk of underfill. Therefore, in the patterns with wide notch openings shown in A-3 and A-4 in Fig. 7A, as in B-3 and B-4 in Fig. 7B and C-3 in Fig. 7C, This is inappropriate because it causes a lack of thickness C.8.Also, making the width L3 of the protrusion 22b, which is the forming member in the notch 5d, smaller than the arm spacing β2 means that the notch 5d in the present invention is formed first. Since this process is performed together with the formation of the front and rear side surfaces 5a in step D in FIG. 1 A-H, A-2 in FIG.
Even if the notch shape is maintained like the pattern shown in
During the forging process of the plate piece 8 indicated by G in FIGS. 1A to 1N, the notch 5d opens, and
- There is a risk that the shape will be similar to the tapered groove shown in 3.
For this reason, from the beginning, the middle L3 was completed! If it is set equal to β2, it will cause underfilling, so it is made slightly smaller than β2.

Furthermore, in the present invention, the length Ll of the upper side 24 on the molding surface 22a, which determines the head length, is made slightly smaller than β1 in the arm, based on the results shown in FIG.

That is, in the same figure, the shape shown in a is the forged raw material 11 before the two plate pieces 8, 8 are pressed and bent, and the one shown in b is the shape of the crank throw after both the plate pieces 8, 8 are pressed and bent. The material 19 is shown in a deformed state, and C indicates the value of Ll in the arm I1. The results of experiments with various changes to I are shown, and in Figure 0, ■ is Ll
When the values of and il are the same, the following shows the deformed state when Ll is successively made smaller than 11. In other words, the contour lines after each transformation according to the values of ■, ■, and ■ are outside the throw contour, whereas the contour lines after the transformation of ■ and ■ are outside the slow contour at the T part and the third part as shown in the figure. , which means that these are missing parts, so it is inappropriate to make the Ll value much smaller than β1 as in ■ and ■, and if it is the same as in ■, the remaining Since the amount of meat becomes too large, which goes against the purpose of reducing excess thickness distortion in the present invention, it is appropriate to make it slightly smaller than 1, as shown in (1) and (2). In addition, the length Ll of the side 25 on the molding surface 22a, which determines the head height, is determined by the pin axis 30.
The height of the head 5 is the diameter of the pin shaft 30, and according to the bending experiment of the plate piece 8, the height of the head 5 is slightly larger than the diameter of the pin when bent 180 degrees. Since the reduction rate of is about 30% at most, it is advantageous to make it slightly larger in consideration of reducing the amount of excess meat, but increasing it too much is disadvantageous because it involves an increase in the amount of excess meat. As described above, the forming surface 2 of the forging tool 22, 22 according to the present invention
By taking into consideration the dimensions of the protrusion 22b for obtaining the notches 2a and 5d, it becomes easy to reliably eliminate the poor material yield caused by the large amount of excess material seen in the prior art.

<Example> A specific example of the method of the present invention is illustrated in FIG.

As already explained, in the present invention, the steps A-C shown in FIGS. , the receiving surface 2 of the pedestal 21 fixed to the bed or floor surface
Lower forging tool 22 and vertical guide surface 21 arranged in 1b
The upper forging tool 22, which can be freely handled by the tool manipulator 32, is applied to the forging tool 22, and forging is performed from the press machine 33 side through the upper metal %1.34.In this way, the notch 5d is Front and rear sides 5a and 5 equipped with
After forming the head 5 having a shape and completing the forging process of the head 5, the material 3 is subjected to the following steps F in FIG. As a result, a crank throw material 19 having a shape and dimensional accuracy capable of reducing the amount of excess thickness can be obtained. In the top view example, it is appropriate to make the height of the protrusion 22b and the height of the upper side 24 side of the molding surface 22a approximately the same height from the viewpoint of ease of press forming.If either one is too high, There is a risk that the tool 22 may slip and escape if it hits the tip first. Also, the inclined wall 27 of the molding surface 22a and the protrusion 22b
is assumed to be a direct surface, but this is not necessarily a straight surface and may be a surface with some degree of curvature, but in such a case, it is necessary to consider fixing the tools 22, 22 and the material 3.

Further, the opening angle between the straight wall 26 and the inclined wall 27 in the projection 22b (the angle of the notch 5d) can be set freely as long as the diameter of the pin shaft 30 can be secured, but in general, about 40 to 50 degrees is appropriate.

<Effects of the Invention> According to the forming method of the present invention, problems in the prior art, namely, the time-consuming processing process that occurs when forging the crank throw head 5 in the plate-shaped material 3, and furthermore, the head 5 can be solved. In addition, there are problems in that it is not possible to maintain an appropriate shape and accurate regulation of dimensional accuracy, and there is also a problem in that the material yield is reduced due to the large amount of excess material that occurs during the pressing and bending of the pair of plate pieces 8, 8 that will later become the arms. , molding surface 22a
It is excellent in that it can be easily solved by forging using a pair of upper and lower forging tools 22, 22 having protrusions 22b.
This improves productivity and results in a crank throw that is more economical and superior in quality.
Zero-stable and uniform forging processing can be easily obtained.

[Brief explanation of the drawing]

Figure 1 A-N is an explanatory diagram of the forming process using the crank throw press bending method, Figure 2 I and ■ are side sectional views showing conventional head forging, and Figure 3 ■ and ■ are forged rough areas using the conventional technology. Fig. 4 is an overall and partial detailed view of the moldability example of the present invention, Fig. 5 is a front view of the crank throw material, and Fig. 6 is a front view of the crank throw material according to the present invention. 7A to 7C are front and side sectional views of the rough ground of each pattern including the embodiment of the present invention and the main part of pressing and bending one plate thereof, and FIG. 8 is a diagram of the head length in the method of the present invention. FIG. 9 is an explanatory diagram of the deformation on each side due to the change, and FIG. 9 is an explanatory diagram of the inclined machining state according to the embodiment of the method of the present invention. 3...Plate material, 5...Head, 5a...Both front and rear sides, 5d...Notch, 21...Scraper, 21a...Vertical guide surface, 22...Forging tool , 22a... Molding surface, 22b... Protrusion, 8... Plate piece, 30...
Pin shaft, 31... Arm, 11... Forged rough ground.

Claims (1)

[Claims] 1. Using a rectangular material with a quadrilateral cross-section, forge a rough material for a crank throw consisting of a head that will later become the pin shaft, and a pair of plate pieces that are connected to both ends of the head in the axial direction of the pin shaft and that will later become the arms. In the molding product, when molding the head, the bottom surface of the head is supported on a vertical guide surface,
Both the front and rear sides following the bottom surface are formed through a forming surface in which the head height and head length of a pair of upper and lower forging tools are regulated as required, and a substantially triangular wall-shaped protrusion provided at the lower center of the forming surface. , both the front and rear sides are forged at the same time to form a roughly trapezoidal shape, and the center lower part and bottom of both the front and rear sides are approximately 3.
A method for forming a forged raw material for a crank throw, which is characterized by obtaining a head having a square groove-shaped notch.