JPH03169448A - Manufacture of long member - Google Patents

Abstract

PURPOSE:To uniformly straighten warpage of a long shaft part over the whole circumference by rolling the long member having executed upsetting and bending with a forming apparatus to straighten the warpage. CONSTITUTION:RR forging composed of the upsetting and the bending is executed with the forming apparatus to form a crankshaft 90. This crankshaft 90 is laid so as to position the journal parts 92, 94 thereof into V shaped grooves 100a, 102a of V-blocks 100, 102 set as prescribed intervals. Successively, grinding wheels 104, 106 are descended and brought into contact with the journal parts 92, 94 under pressure, and a rotary shaft 108 is rotated by a rotary driving source an the rolling is executed on the journal parts 92, 94 with the grinding wheels 104, 106. By this method, the warpage of journal parts 92, 94 is uniformly straightened over the whole circumference.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a long member, and more specifically, the present invention relates to a method for manufacturing a long member, and more specifically, to perform upsetting processing by applying pressure on both end faces of a long material in the axial direction. , a long member in which a predetermined portion of the material is bent by applying pressure in a direction perpendicular to the axial direction, and further bending that may occur in the composite-molded long member is corrected by rolling processing. The present invention relates to a method for manufacturing a member.

[Prior Art] For example, as a method for manufacturing a crankshaft, a rod-shaped material is pressurized in its axial direction to perform upsetting processing, and a portion of the rod-shaped material corresponding to the pin portion of the crankshaft is In order to perform bending by applying pressure in a direction perpendicular to the axial direction, the so-called RR forging method has come to be widely adopted.

Conventionally, various devices employing this type of forging method have been proposed, and the technical idea thereof is disclosed, for example, in Japanese Patent Publication No. 4312995 and Japanese Patent Publication No. 49-24337.

[Problems to be Solved by the Invention] However, even in the crankshaft formed by the RR forging method, bending may occur after forming due to various reasons.

First, after the composite forming process of bending and upsetting is completed, when the die fitted to both ends of the material and the punch that presses the material from above are removed from the material, the force between the guide and the presser punch is removed. If the timing of the displacement operation is not consistent, there is a risk that the crankshaft will be bent. In other words, if the die is not far enough away from the material and there is a gap between both ends of the crankshaft and the die, and the presser punch that is in close contact with the upper side of the crankshaft is raised,
Depending on the degree of close contact, the presser punch may lift the crankshaft, causing both ends of the crankshaft to collide with the die, resulting in bending.

Further, residual stress may exist in the crankshaft due to the bending process during RRta construction, and depending on the residual stress, there is a risk that the crankshaft may be bent after the product is completely removed from the goo or punch.

In addition, when performing axial drawing by applying pressure in the axial direction by contacting a punch to both end surfaces of the shaft of a material consisting of a long member,
Bending may occur near the central portion of the material.

Furthermore, in order to easily process the material, the processing part is heated in advance, but the crankshaft shrinks due to cooling after the forming process is completed, and as a result,
There is a risk of bending.

In order to correct such bending of the crankshaft, in the conventional technology, a press machine for straightening the bending is used, but this naturally increases the number of press steps in the manufacturing process. The mold cost also increases, making it uneconomical.

There is also a method of straightening by applying pressure in the opposite direction to the bending direction using a simple press device, but with this method, the bending direction and amount of bending must be measured by skilled hands, and moreover, Since correction is not possible, production efficiency does not increase much.

On the other hand, so-called rolling processing, in which a rotating grinding wheel is pressed against the entire circumference of a shaft to correct bending, is applied to, for example, correcting bent engine valves, and is a known technique. I can say that. However, in conventional crankshaft molded products that are molded with a burr between the upper and lower dies, the burr is attached to both sides of the shaft, and the shaft is also not perfectly round. Because it is far from and has distortion,
It was not possible to apply rolling correction.

The present invention has been made to solve the above-mentioned problems, and is a long member molded by RRiR construction, which is low cost, improves production efficiency, and does not require measurement of bending direction or bending amount. It is an object of the present invention to provide a method for manufacturing a long product that uniformly corrects the curvature of the shaft over the entire circumference.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention clamps a part of a material extending in the axial direction with a pair of punches, and punches are arranged on both sides of the clamped portion of the material. A method for manufacturing a long member in which a mold is moved in cooperation with a die provided to carry out a composite shape of upsetting and bending, the elongated member after the upsetting and bending. It is characterized by applying rolling processing to straighten the bend.

[Function] In the method for manufacturing a long member according to the present invention, upsetting is performed by applying pressure to both end surfaces of the material in the axial direction, and at the same time, applying pressure to a predetermined portion of the material in a direction perpendicular to the axial direction. A round product is obtained by bending, and then a rolling process is applied to the entire circumference of the shaft portion of this round product to correct the westward bulge.

[Example] Next, regarding the method for manufacturing a long member according to the present invention, a crankshaft will be exemplified and preferred examples thereof will be described below. Regarding this example, first, an apparatus for forming a crankshaft as a long member using the RR11it manufacturing method will be described, and then a rolling process will be described.

In FIGS. 1 and 2, reference numeral 10 indicates an apparatus for forming the crankshaft according to the present embodiment by RRIR construction. The molding device 10 includes a base 12, and a large diameter hole is defined between the base 12 and a guide block 14 disposed at the center of the upper surface of the base 12. The lower cylinder 16 is formed using the section.

That is, the lower cylinder 16 is formed by fitting the head force bar part 17a and the rod cover part 17b into the hole,
A piston 18 is disposed inside it. In the figure, reference numeral 16a indicates the piston 18 and the head force bar part 17.
A pressure chamber as the first main buffer section is shown in the drawing between a and a.

Therefore, a piston rod 20 is integrally formed to bulge vertically upward from one end surface of the piston 18. In this case, a spring 22 made of a coil spring is disposed inside the pressure chamber 16a, and a fluid buffer chamber 23 as a first sub-buffer section is defined between one end surface of the piston 18 and the rod cover section 17b. be done. A receiving punch 24 is disposed at the tip of the piston rod 20, and this receiving punch 24 passes through a hole formed in the guide block 14. Note that the receiving punch 24 has an arcuate receiving surface 24a on its tip surface.
Shape it.

Block bodies 26a and 26b are erected on the base 12 outside the guide block 14, and the block bodies 26
Cylinders 28a and 28b are attached to a and 26b, respectively.

Rods 3Oa, 30b extend from the cylinders 28a, 28b to face each other, and the rods 30a, 30b extend from the cylinders 28a, 28b to face each other.
Slide tables 32a and 32b are engaged with the tip of 0b. The sliding table 32a132b can move forward and backward on the guide bar 14. The upper corner of the sliding base 32a is cut out to form an inclined surface 34a, and a die 36a is integrally disposed inside the sliding body 32a. A machining surface 38a having a predetermined shape is formed at one end of the die 36a so that a material to be described later is pressurized to perform machining corresponding to the weight portion of the crankshaft. In addition, a useful tag part 40 is provided for penetrating the die 36a and performing axial drawing on the material.
Draw a. A first punch 4 is provided in the serving hole portion 40a.
4a is fitted.

The first punch 44a is disposed in a chamber defined by the sliding table 32a, and has a flange portion 4 integral with the first punch 44a.
6a and the end of the die 36a.
a is interposed therebetween, and one end of a piston rod 52a extending from a cylinder 50a attached to the slide table 32a engages with the end of the flange portion 46a.

The sliding table 32b is constructed in substantially the same manner as the sliding table 32a described above, and the same reference numerals and b are added to the same structural elements, and detailed explanation thereof will be omitted. do.

Next, a lifting table 54 is provided above the sliding tables 32a and 32b. This elevating table 54 consists of vertical surfaces of the block bodies 26a, 26b and inclined surfaces 34a, 34b of the sliding tables 32a, 32b.
The cam members 56a and 56b are held in engagement with the cam members 56a and 56b. An upper cylinder 58 is formed by forming a large diameter hole in the center of the lifting table 54 and closing this large diameter hole with a head force bar 57a and a rod cover 57b.

A piston 60 is disposed inside this upper cylinder 58. A pressure chamber 58a serving as a second main buffer is defined between one end surface of the piston 60 and the head cover 57a, and a plurality of springs 61 are disposed inside the pressure chamber 58a.

A fluid buffer chamber 63 is formed in the lower part of the piston 60 as a second sub-buffer section. A presser punch 64 is engaged with the tip of a piston rod 62 that integrally bulges vertically downward from the piston 60, and the tip of the presser punch 64 has an arcuate presser surface 64a and a crankshaft, which will be described later. The machined surface 64b corresponding to the weight portion is shaped.

Note that the presser punch 64 and the receiving punch 24 constitute a second punch 66.

Next, the cam members 56a and 56 are located on the lower surface of the lifting table 54.
A plurality of inclined pins 67a, 67b are formed to protrude inwardly from each other so as to spread out from each other, while sliding bases 32a, 32b
The holes 68a and 68b are formed in the holes 68a and 68b, into which the inclined bins 67a and 67b are loosely fitted, respectively. That is, the inclined bins 67a, 67b and the insertion holes 68a, 68
A cam mechanism is constituted by b, and the sliding tables 32a and 32b can be moved toward or away from each other by displacement of the lifting table 54.

Next, a hydraulic circuit for driving the upper cylinder 58 and the lower cylinder 16 is shown in FIG. This extraction circuit includes an accumulator 70 as a pressure source, and a pipe line 72 connected to this accumulator 70 branches into a pipe line 74a174b on the way. Therefore, the pipe line 74a
includes a first on-off valve 75a, a check valve 76a, and a relief valve 7.
8a, which communicates with a pressure chamber 58a formed between the head force bar 57a and one end surface of the piston 60.

Further, the pipe line 74b includes a second on-off valve 75b and a check valve 76.
b and a relief valve 78b, which is connected to the piston 18.
It communicates with a pressure chamber 16a defined between one end surface of the head force bar 17a and the head force bar portion 17a. Further, a pipe line 74c branched from the pipe line 74a communicates with the fluid buffer chamber 63,
On the other hand, a pipe line 74a branched from the pipe line 74b is communicated to the fluid buffer chamber 23.

Next, the process of forming the crankshaft 90 from a long material using the crankshaft forming apparatus 10 configured as described above will be explained.

First, since the material W is hollow, there is a possibility that the holes existing inside the material W may be clogged during the cutting process described later. For this reason, only the portion corresponding to the weight portion, excluding the pin portion, is subjected to high-frequency induction heating treatment in advance.

Therefore, the sliding stands 32a, 32b are attached to the cylinders 28a, 28.
While separating from each other under the drive action of b, the lifting platform 5
4 is raised, and in this state, each die 36a, 3
A cylindrical material W is placed on 6b.

Next, the first on-off valve 75a is opened, and the accumulator 7
Pressure oil as pressurized fluid is supplied from 0 to the pressure chamber 58a via the check valve 76a. As this pressure oil is supplied, the piston 60 is displaced downward in the figure, which causes the presser punch 64 to descend. Therefore, the part of the material W that corresponds to the pin part of the crankshaft is punched with a second punch 66.
It is held between the receiving surface 24a of the receiving punch 24 and the pressing surface 64a of the presser bunch 64. At that time, since the receiving punch 24 is pressed by the presser punch 64, the pressure chamber 1
The pressure oil in 6ia is led out from the relief valve 78b to the accumulator 70 side, the receiving bunch 24 is lowered, and the spring 22
absorbs the downward impact of the receiving punch 24.

Next, the elevator platform 54 is lowered as a whole, and
The cylinders 28a and 28b are driven to move the slide tables 32a and 32.
b are displaced in a direction toward each other. As a result, the working holes 40 of the respective dies 36a and 36b are formed at both ends of the material W.
Axial drawing is performed through a and 40b. Note that at this time, the inclined pins 67a, 6 installed on the lifting platform 54
7b loosely fits into the holes 68a and 68b formed in the sliding bases 32a and 32b.

Furthermore, the slide tables 32a and 32b are moved closer to each other under the driving action of the cylinders 28a and 28b, and both end surfaces of the material W subjected to the axial drawing process are pressed by the tips of the first bunches 44a and 44b. Therefore, the raw material W is compressed in the axial direction and pre-compression processing is performed, and the processing surfaces 38 of the dies 36a and 36b are
An enlarged diameter portion that follows the processed surface 64a is provided between a, 38b and the second punch 66.

Next, the lifting table 54 is further lowered, and the cam member 56
a, 56b, the slope 34a of the sliding bases 32a, 32b
, 34b. Therefore, the first bunches 44a, 44
b further pressurizes both end surfaces of the material W in the axial direction,
The processed surfaces 38a and 38b of the dies 36a and 36b press the portions of the material W that correspond to the weight portions, and
A presser surface 64a of the presser punch 64 forms a bottle portion of the crankshaft.

As a result, a cylindrical and bent crankshaft 90 is formed (see FIG. 2).

At this time, the pressure oil in the pressure chamber 58a, together with the auxiliary action of the elastic force of the spring 61, absorbs the impact caused by the reaction force applied to the presser bunch 64. That is, the force that tends to be displaced due to the reaction force of the presser bunch 64 is buffered by the hydraulic pressure in the pressure chamber 58a, and causes a pressure change in this hydraulic pressure.
Pressure oil in the pressure chamber 58a is led out to the Akinimulator 70 side via the IJ-F valve 78a.

Next, the lifting platform 54 rises, and the sliding platforms 32a, 32b are moved under the mutually expanding shape of the inclined bins 67a, 67b and the withdrawal action of the rods 30a, 30b of the cylinders 28a, 28b.
move away from each other. In this case, as is easily understood, the sliding bases 32a and 32b are separated from each other with a slight delay from the upward movement of the tilt pins 67a and 67b. The inclined bins 67a and 67b are the sliding tables 32a and 32b.
This is because they are loosely fitted into the fitting holes 68a and 68b. The crankshaft 90 is not particularly lifted by the lifting operation of the lifting table 54. die 36
This is because both ends are firmly held by a and 36b. At this time, the first on-off valve 75a is closed to prevent pressure oil from flowing into the pressure chamber 58a, and the pressure oil in the fluid buffer chamber 63 is transferred to the piston 60.
prevents downward displacement of the Similarly, the second on-off valve 75b is closed to prevent pressure oil from flowing into the pressure chamber 16a, and the pressure oil in the fluid buffer chamber 23 prevents the piston 18 from moving upward in the figure. .

Next, the cylinders 50a and 50b are driven to displace the first punches 44a and 44b in a direction toward each other against the elastic force of the coil springs 48a and 48b. Therefore, both end surfaces of the crankshaft 90 obtained from the material W are pressed, and the crankshaft 90 is pressed against the die 36.
Leave from a and 36b. That is, the crankshaft 90 is essentially ejected from the dies 36a, 36b.

Next, the second on-off valve 75b is brought into communication, and the pressure chamber 1
Pressure oil is supplied to the piston 6a to raise the piston 18, and the receiving punch 24 is positioned at a position for processing the next material.

Next, the crankshaft 90 as a molded product obtained by RR forging as described above is particularly subjected to rolling processing in order to correct bending caused by, for example, springback (see Fig. 4). (see (a), w)).

That is, in this rolling process, in order to arrange the crankshaft 90, two V blocks 100 are
, 102 are provided at predetermined intervals, and each V block 100, 102 has a V-shaped groove 100a, 102 on its upper surface.
It has a. The journal portions 92 and 94 of the crankshaft are placed and fixed in these square grooves 100a and 102a. Grinding wheels 104 and 106 are rotatably provided from above the journal parts 92 and 94 and press against them. Both of these two grinding wheels 104 and 106 are rotated by a rotational drive source (not shown) via a rotating shaft 108.

Next, the two grinding wheels 1 are moved by a lifting device (not shown).
04 and 106 are lowered to press against the journal parts 92 and 94, and the rotating shaft 108 is rotated by the rotational drive source. As a result, the grinding wheels 104 and 106 are connected to the journal portions 92 and 94.
Rolling process is performed to correct any bends.

As described above, in this embodiment, the journal portion of the crankshaft can be corrected by rolling processing. Moreover, it has the advantage of being low cost and requiring no measurement of the bending direction or bending amount.

In addition, as a rolling processing mechanism, in addition to the above embodiment, for example, as shown in FIG. 5, two grinding wheels 110,
A crankshaft 90 may be disposed between the grinding wheel 112 and one grinding wheel 114 to perform the rolling IJ process.

Furthermore, in addition to the grinding wheel, rolling processing may be performed by shifting the crankshaft 90 between two grinding wheel surfaces 120 and 122, as shown in FIG.

Furthermore, the crankshaft that has been subjected to the rolling process as described above may be further subjected to a grinding process, if necessary, to obtain a product with even more precise bending correction.

[Effects of the Invention] The method for manufacturing a long member according to the present invention has the following effects.

Upsetting is performed by applying pressure to both end faces of the material in the axial direction, and a predetermined portion of the material is pressurized in a direction perpendicular to the axial direction to bend the elongated member into a predetermined shape. After forging, rolling is performed on the shaft of the long member to correct the bend. Therefore, it is possible to achieve the effect of being able to uniformly correct the axial bend of the elongated member over the entire circumference at a low cost and without the need to measure the bending direction or lJh amount.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the state of the material to be formed into the crankshaft before processing in the crankshaft forming apparatus according to the embodiment of the present invention, and FIG. 2 shows the state of the crankshaft from the state shown in FIG. A vertical cross-sectional view of the state in which the forming process has proceeded, FIG. 3 is a circuit diagram of the pressure oil incorporated in the device of the present invention, and FIGS. 4(a) and (5) are for straightening the bending of the crankshaft according to this embodiment. A schematic front explanatory view and a schematic side explanatory view of a device for straightening bends, and FIGS. FIG. ...Forming device...Lower cylinder...Receiving punch a, 28b...Cylinder a, 32b...Sliding table a, 36b...Gui a, 44b...Punch a, 50b...・Cylinder... Lifting table a, 56b... Cam member... Upper cylinder 66... Punch 67a, 67b... Inclined pin 70... Accumulator 74a, ? 4b-Pipe lines 75a, 75b... Opening/closing valves 100, 102... V blocks 104, 106, 110, 112, 114... Grinding wheels 120, 122... Grinding wheel surface

Claims (2)

[Claims] (1) A part of the material extending in the axial direction is held between a pair of punches, and the mold is moved and installed under the cooperation of the dies arranged on both sides of the holding part of the material. A method for manufacturing a long member that performs a composite forming process of upsetting and bending, characterized in that the long member after the upsetting and bending is rolled to correct the bending. Production method. (2) A method for manufacturing an elongated member according to claim 1, wherein the elongated member comprises a crankshaft, and the journal portion of the crankshaft is subjected to rolling processing.