JP3840954B2 - Forged mold structure of crankshaft - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a die structure for the purpose of forging a crankshaft, and in particular, a crankshaft rough material previously forged into a predetermined shape is pressure-restrained by a lower die and an upper die for wrist-like processing, and the crankshaft coarseness is The present invention relates to the structure of a forging die that corrects the bending of a material.
[0002]
[Prior art]
As is well known, the hot forging of crankshafts for internal combustion engines is roughly divided into three processes: (1) bending, (2) wasteland, and (3) finishing, and a trimming press in the trim process. This is completed by trimming the “burr” attached to the outer periphery of the shape, but a subsequent reclaim process (coining process) may be performed for the purpose of correcting the bending of the crankshaft rough material.
[0003]
[Problems to be solved by the invention]
For example, the restric process is performed by positioning and placing the crankshaft coarse material after forging on the lower die, lowering the upper die, and pressurizing and restraining the crankshaft coarse material with these upper and lower dies. It is intended to correct bending or tilting in the direction, but in general, processing is performed in a state where the line connecting the axis of the crankshaft coarse material itself and the axis of the crankpin is in a horizontal state. Therefore, it is not possible to correct the counterweight fall that is located on the opposite side of the crankpin across the crankshaft rough material axis, that is, the counterweight tilt with respect to the crankshaft coarse material axis. .
[0004]
Further, by changing the way the counterweight coarse material is placed, it is possible to correct the bending of the counterweight to some extent at the same time as correcting the bending. However, a certain clearance is secured in advance between the crankshaft rough material and the upper and lower molds in order to reliably position the crankshaft rough material and prevent the galling phenomenon. In addition, the counterweight collapse cannot be corrected.
[0005]
The present invention has been made paying attention to the problems as described above, and in the re-striking process of the crankshaft rough material, in particular, the correction of the bending of the crankshaft rough material and the correction of the fall of the counterweight are within one process. It is intended to provide a mold structure that can be surely performed.
[0006]
[Means for Solving the Problems]
In the first aspect of the present invention, the forged crankshaft coarse material is positioned in a horizontal state on the lower mold for wrist-like processing, and then the crankshaft coarse material is pressed by the lower mold and the upper mold. It is a forged die structure that is restrained and corrects bending, and faces the opposite sides of each counterweight of the crankshaft rough material that will be positioned in this lower die of the lower die. A pair of lower dies that are arranged and slide-driven in accordance with the approach and separation of the upper and lower molds to move toward and away from each other in the axial direction of the crankshaft, and a pair of lower dies on the lower mold side of the upper mold an inner position corresponding with each other are and opposed on either side of the counterweight Rutotomoni, each have a height spanning the entire height of the counterweight, when close together the pair of lower die The lower die is characterized in that it comprises a pair of upper dies for pressure restraining the counterweight of the crankshaft coarse material in its thickness direction by being driven close to the same direction.
[0007]
In the invention described in claim 2, on the premise of claim 1, the upper die and the lower die are formed with inclined cam surfaces, respectively, and the lower die is formed by sliding contact between these inclined cam surfaces. It is characterized by being driven by the upper mold.
[0008]
Therefore, in the inventions according to the first and second aspects, the behavior in which the bending of the crankshaft rough material is corrected by the vertical pressing restraint force due to the approach between the upper and lower molds is the same as the conventional one. At the same time, the pair of lower dies are driven to slide in the horizontal direction under the driving force due to the approach between the upper and lower molds, and the lower dies further slide the pair of upper dies in the same direction. Each counterweight is restrained in a horizontal direction by a pair of upper dies. As a result, the fall of the counterweight with respect to the axis of the crankshaft is corrected.
[0009]
【The invention's effect】
According to the first and second aspects of the present invention, since it is possible to correct the bending of the counterweight in the horizontal plane at the same time as correcting the bending of the crankshaft in the vertical direction, the dimensions of the crankshaft rough material in the horizontal direction can be corrected. In addition to reducing variation and reducing machining allowances in subsequent processes, it is possible to reduce the number of processes, and by simply adding a lower die and an upper die to an existing forging die, There is an effect that can achieve the purpose.
[0010]
In addition, by pressing and restraining each counterweight with a pair of upper dies from the lateral direction, the flash marks attached to the outside of each counterweight can be actively crushed and smoothed after trimming. There are advantages you can do.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1 and subsequent drawings show a preferred embodiment of a forging die structure according to the present invention, and in particular, FIG. 1 is a longitudinal sectional view of a forging die for wrist-like processing, and FIG. 2 is a line AA in FIG. FIG. 3 is a plan view of only the lower mold in FIG. 1 corresponds to a cross section taken along line BB in FIG.
[0012]
As shown in FIGS. 1 to 3, the forging die 1 is formed with a lower die 2 and an upper die 3 that moves up and down with respect to the lower die 2. As described above, for example, bending, wasteland, A crankshaft rough material (here, illustrated as a so-called single counter type crankshaft rough material) S forged and formed in three finishing steps is supplied to the forging die 1 after obtaining a subsequent trimming step. Will be. The crankshaft coarse material S has a known structure in which a counterweight W is integrally formed on the opposite side of the crankpin P across its own axis.
[0013]
Each of the lower mold 2 and the upper mold 3 is formed with a recess 2a or 3a having a shape faithful to the shape of the rough material for receiving the crankshaft rough material S. By positioning the shaft rough material S and then lowering the upper die 3 and clamping it, the crankshaft rough material S is given a vertical restraining force to correct its bending. ing.
[0014]
A positioning projection 4 for receiving the counterweight W is integrally formed at a position where the counterweight W is received in the recess 2a on the lower mold 2 side, and the positioning projection 4 is sandwiched between the positioning projection 4 and the counterweight W. A pair of lower dies 5 and 5 are arranged opposite to each other at a predetermined distance so as to face each other. The pair of lower dies 5, 5 can approach and separate from each other within the range of the minute stroke S1, and are urged in a direction away from each other by an elastic means 6 such as a compression coil spring. Further, the opposing surfaces of the lower dies 5, 5 are inclined surfaces 5a, and inclined cam surfaces 5b are individually formed on the shoulder portions of the lower dies 5, 5.
[0015]
On the other hand, the upper die 3 is provided with an inclined cam surface 7 corresponding to the inclined cam surface 5b on the lower dies 5 and 5, and a positioning block 8 facing the positioning protrusion 4 is provided. A pair of upper dies 9, 9 are arranged opposite to each other across the positioning block 8 so as to face each other. The pair of upper dies 9, 9 are backed up by the holder block 10 on the upper surface side, can be moved close to and away from each other within the range of the minute stroke S2, and can be moved up and down within the range of the stroke S3. While being urged in a direction away from each other by elastic means 11 such as a spring, it is formed in a cross-sectional wedge shape so that it can be accommodated in a facing gap between the lower dies 5, 5. The inclined surface 9a on the back side is in sliding contact with the inclined surface 5a on the lower dies 5, 5 side.
[0016]
The lower mold 2 is provided with a protruding plate 12 for pushing up the processed crankshaft rough material S.
[0017]
Therefore, according to the present embodiment, if the upper mold 3 is lowered and clamped after positioning the crankshaft rough material S in the recess 2a on the lower mold 2 side, each recess 3a, Since 2a is faithful to the shape of the crankshaft rough material S, the crankshaft rough material S is pressure restrained in the vertical direction, and the bending of the crankshaft rough material S itself is corrected by the pressure restraining force. Is done. As far as this behavior is concerned, it is the same as the conventional one.
[0018]
In this mold clamping process, as shown in FIGS. 4A to 4C, the lower end of the upper die 9 gradually enters the facing gap between the lower dies 5, 5 as the upper die 3 descends, Eventually, as shown in FIGS. 5A and 5B, the lower ends of the upper dies 9, 9 become so-called bottom-butted with respect to the lower die 2, and the upper dies 9, 9 and the lower dies 5, 5 The inclined cam surfaces 5b on the lower dies 5, 5 side and the inclined cam surface 7 on the upper die 3 side come into sliding contact with each other at the same time as the inclined surfaces 9a, 5a are in sliding contact with each other. At this time, a predetermined clearance is secured between each of the upper dies 9, 9 and the counterweight W so that they are not in contact with each other.
[0019]
With the sliding contact between the inclined cam surfaces 5b and 7, the lower dies 5 and 5 are both slid to approach each other, and the upper dies 9 and 9 move relatively upward while the lower dies 5 and 5 move relatively upward. When driven by 5, the upper dies 9, 9 also move closer to each other. When the upper die 3 has reached the bottom dead center, the upper dies 9, 9 floating from the upper die 3 have their upper and lower dies 3, 2 clamped to each counterweight W. Then, the pressure weight is restrained and the fall of the counterweight W is corrected by so-called restric processing.
[0020]
That is, as compared with the conventional case with reference to FIG. 6, in the conventional case, there are no movable parts such as the lower dies 5, 5 and the upper dies 9, 9, and the upper and lower dies as described above. Since a predetermined clearance C is provided between each of the concave portions 3a, 2a of 3 and 2 and the crankshaft rough material S, for example, the counterweight W is tilted or twisted as shown in FIG. In this case, at least the clearance C is not corrected.
[0021]
On the other hand, in the present embodiment, as described above, the movable upper dies 9, 9 driven through the lower dies 5, 5 pressurize and restrain the counterweight W from both sides with a large load. Therefore, even the counterweight W corresponding to the clearance C as shown in FIGS. 6 and 7 is reliably corrected, and the dimensional variation of the counterweight W is greatly suppressed. At the same time, when a flash mark at the time of trimming remains on the outer peripheral surface of the counterweight W, the flash mark is also actively crushed and smoothed.
[0022]
When the upper die 3 starts to rise again after reaching the bottom dead center in the state of FIG. 5C, the upper dies 9, 9 and the lower dies 5, 5 are separated from each other in the reverse order. In particular, the upper dies 9, 9 rise smoothly together with the upper die 3 without causing a galling phenomenon with the crankshaft rough material S, and finally one cycle is completed with the upper and lower dies 3, 2 being opened. Then, the crankshaft rough material S after the wrist-like processing is protruded above the lower mold 2 by the protruding plate 12 shown in FIG.
[Brief description of the drawings]
FIG. 1 is a view showing the structure of a forging die for wrist-like processing as a preferred embodiment of the present invention, and is a cross-sectional view taken along line BB in FIG.
2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a plan view of only the lower mold in FIG. 1;
FIG. 4 is an operation explanatory diagram of a main part of FIG. 1;
5 is an operation explanatory diagram of a main part of FIG. 1. FIG.
FIG. 6 is a schematic explanatory diagram of a conventional construction method.
FIG. 7 is a schematic explanatory diagram of a conventional construction method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Forging die 2 ... Lower die 2a ... Concave 3 ... Upper die 3a ... Concave 5 ... Lower die 5b ... Inclined cam surface 7 ... Inclined cam surface 9 ... Upper die S ... Rough crankshaft W ... Counterweight

Claims (2)

After the forged molded crankshaft coarse material is positioned horizontally on the lower mold for wrist-like processing, the crankshaft coarse material is pressure-restrained by these lower mold and upper mold to correct the bending. Forged mold structure,
Of the lower mold, the crankshaft rough material to be positioned on this lower mold is placed opposite to both sides of the counterweight corresponding position, and is driven to slide according to the approach and separation between the upper and lower molds. A pair of lower dies that move toward and away from each other in the axial direction of the crankshaft,
Rutotomoni disposed opposite on either side of and counterweight an inner position corresponding between the pair of the lower die of the lower die side of the upper die, each have a total height to span the height of the counterweight, a pair A pair of upper dies that press and restrain the counterweight of the crankshaft rough material in the plate thickness direction by being driven in the same direction by the lower dies when the lower dies approach each other;
A forged die structure of a crankshaft characterized by comprising: The upper die and the lower die each have an inclined cam surface, and the lower die is driven by the upper die by sliding contact between the inclined cam surfaces. Forged die structure of the described crankshaft.

Images