JPH05169177A - Manufacture of crankshaft and apparatus to be used for it - Google Patents

Abstract

PURPOSE:To shorten the length of a crankshaft to contribute to miniaturization of an internal combustion engine. CONSTITUTION:Discoidal inserting parts 3 are inserted respectively between counter weights 805 of the crankshaft material 800 and a gap 5 is formed between the side face 805a and the inserting part 3 of the counter-weight 805. Under this state, the interval between the counterweights 805 which face each other is reduced by driving a press apparatus and pressing a crankshaft material 800 forcedly in the direction of the shaft length. The abnormal deformation of the counterweight 805 is prevented by the inserting part 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a crankshaft and a device which can be used for the same. INDUSTRIAL APPLICABILITY The present invention can be applied, for example, to manufacturing a crankshaft used in an internal combustion engine of a vehicle.

[0002]

Crankshafts are used in engines, such as internal combustion engines. The crankshaft converts the reciprocating motion of the piston into a rotary motion via a connecting rod to take out torque. Here, in FIG.
1 shows a crankshaft as a finished product that has undergone a cutting process. As shown in FIG. 5, the crankshaft 100 includes a journal 101 having a shaft core, a plurality of pins 103 arranged at predetermined intervals in the circumferential direction of the shaft core, and a plurality of counterweights 105. ing.

[0003]

By the way, in recent years, the present applicant has tried to manufacture a crankshaft 100 in which the distance between the counterweights 105 facing each other is narrowed. According to such a crankshaft 100, the axial length thereof is shortened, which can contribute to downsizing and weight reduction of the internal combustion engine.

However, in this case, there is a problem in molding the crankshaft material due to the narrowing of the interval dimension of the counterweights 105 facing each other. That is, in the case of forging a crankshaft material as a material before cutting, the wall thickness of the mold parts that form the counterweights facing each other becomes thin, and there is a limit to improving the strength and durability of the mold parts. There is. Therefore, the mold part is easily damaged in a short period of time. Such a problem also occurs when casting a crankshaft material.

The present invention has been made in view of the above-mentioned circumstances, and a method of manufacturing a crankshaft that can reduce the distance between the counterweights facing each other and can contribute to downsizing and weight reduction of an internal combustion engine or other engine. And it aims at providing the apparatus which can be used for this.

[0006]

A method for manufacturing a crankshaft according to the present invention comprises a journal having a shaft core, at least one pin arranged at a predetermined interval in the circumferential direction of the shaft core, and a plurality of counterweights. A forming step of forming a metal crankshaft material provided with and a pressurizing step of narrowing the interval between at least two counterweights facing each other by strongly pressing the crankshaft material in the axial direction. Is carried out in order.

In the forming step, the crankshaft material can be formed by forging and casting. At this time, pins, counterweights and journals are also molded. In the pressurizing step, the crankshaft material is strongly pressed in the axial direction, but in this case,
Both the one end and the other end of the crankshaft in the axial length direction may be strongly pressed in the axial length direction, or the other end may be strongly pressed while holding one of the one end and the other end. good.

The pressurizing step is generally performed while the temperature of the crankshaft material is high in order to secure the deformability of the crankshaft material. However, depending on the amount of deformation, the material of the crankshaft material, etc. Can also be performed in a cold state where the crankshaft material is in the normal temperature range. It is also preferable to perform a heating step of heating the whole or a part of the crankshaft material prior to the pressurizing step. This is because the deformability of the crankshaft material can be secured. The heating temperature can be appropriately selected according to the type of crankshaft material, but is 800 when the crankshaft material is carbon steel or alloy steel.
It can be about 950 ° C. When a part of the crankshaft material is heated, mainly the counterweight, the pin, etc. are locally heated, but the journal may be heated too much or not at all. The main reason is to suppress the deformation of the journal and ensure the accuracy of the journal axis. When heating the entire crankshaft material, a heavy oil furnace, an electric furnace or the like can be adopted. Moreover, when heating a part of crankshaft, an induction heating furnace etc. can be employ | adopted.

In the pressurizing step, a rigid member that is loosely fitted between the counterweights with a gap, a deformable member that can be plastically or elastically deformed in the thickness direction, or a fluid such as sand, magnesia, or carbon powder is used. , They may be inserted between the counterweights facing each other. When the crankshaft is strongly pressed in the axial direction with the rigid member, the deformable member, and the fluid being inserted between the counterweights in this manner, it is advantageous to reduce or avoid unnecessary deformation of the counterweights. A spring member such as a leaf spring or a disc spring can be used as the deformable member.

In the pressurizing step, a regulating member that abuts on the journal is used, and the regulating member is abutted on the journal to regulate the displacement and deformation of the journal in the direction perpendicular to the axis of the crankshaft material (that is, in the radial direction), and You can also apply strong pressure in the long direction. This is advantageous for maintaining the accuracy of the journal axis. The material of the crankshaft material used in the present invention can be appropriately selected from steel and titanium alloys, and the number of counterweights can be appropriately set, for example, two or more.

The crankshaft manufacturing apparatus according to the present invention is an apparatus that can be used when carrying out the above-described manufacturing method. That is, a crankshaft manufacturing apparatus according to the present invention is provided between a base portion on which a crankshaft material is arranged and a counterweight which is movably arranged on the base portion in the axial direction of the crankshaft material and faces each other. The thickness of the insertion part is
It is characterized in that it is a predetermined value smaller than the interval between counterweights facing each other that should be narrowed.

In the manufacturing apparatus according to the present invention, the insertion portion is
It is arranged at the base and is movable in the axial direction of the crankshaft material. The movably arranged structure can be appropriately selected, and for example, a form in which the insertion part is slid or a form in which the insertion part is moved in a state where a gap is formed between the insertion part and the base part can be adopted. The thickness of the insertion portion is set to be a predetermined value smaller than the distance between the counterweights facing each other, which should be narrowed. The size of the predetermined value depends on the type of crankshaft material, but is generally about 0.1 to 5 mm, and more preferably about 0.5 to 2 mm. Since the thickness of the insertion portion is small, the interval between the counter weights is narrowed. The insertion portion can be formed of a rigid material such as steel, titanium alloy, ceramics (alumina, silicon nitride, silicon carbide, etc.).

[0013]

By strongly pressing the crankshaft material in the axial direction, the distance between at least two counterweights facing each other is narrowed. At this time, the insertion part moves in the axial direction of the crankshaft.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. The manufacturing apparatus according to this example will be described. This manufacturing apparatus is equipped in the press molding apparatus. As shown in FIG. 1, the positioning member 2 is provided on the base 1 in the direction of arrow A1 and A2.
It is equipped so that it can move in any direction. The positioning member 2 is
It has a flat sliding surface 20, and a sliding surface 21 and an abutting surface 22 that are stepwise. Between the counterweights 805 of the crankshaft member 800 facing each other, a large number of board-shaped insertion portions 3 are inserted. Many insertion parts 3
Of these, the insertion portion 3A is held in the holding hole 1a of the base portion 1. Since the insertion portion 3A cannot move in the axial direction of the crankshaft 800, the surface portion 30A of the insertion portion 3A can be the processing reference surface.

In this embodiment, the spring member 4 is interposed between the adjacent insertion portions 3. The spring member 4 may be a coil spring, a leaf spring, a disc spring, or the like. It is preferable that the spring constant of the spring member 4 is relatively large from the viewpoint of ensuring the holding property of the counterweight 805. In such a state, each insertion portion 3
Are inserted between the counterweights 805 of the crankshaft member 800 facing each other through the gap 5. The thickness L of the gap 5 can be generally set to 0.05 to 2.5 mm.

In this embodiment, a barren forging die and a finish forging die are used to perform a first barren forging, a second barren forging, and a finish forging of a rod-shaped metal material (material: S55C) in a hot state.
Further, in the deburring step, the pin 803 is twisted in the circumferential direction by a predetermined angle, whereby the crankshaft member 800
To get The crankshaft material 800 includes a journal 801 having an axis, a plurality of pins 803 arranged at predetermined intervals in the circumferential direction of the axis, and a plurality of counterweights 805. In this counterweight 805, a side surface 805a is formed with a draft angle for the die removal from the rough forging die and the finish forging die.

The hot state (generally 800 to 90)
With the crankshaft material 800 (0 ° C.) arranged in the base portion 1, the predetermined insertion portion 3 is inserted between the counterweights 805 of the crankshaft material 800 facing each other. In that state, when the positioning member 2 is moved in the direction of the arrow A1, the insertion portion 3 is biased by the spring member 4,
The abutting surface 22 of the positioning member 2 is brought into contact with the positioning member 2 to be positioned at a fixed position. In this state, as shown in FIG. 1, between the surface portion 30 of the insertion portion 3 and the side surface 805a of the counterweight 805, the end surface 31 of the insertion portion 3, the outer peripheral surface 803a of the pin 803, and the outer periphery of the journal 801 are provided. A gap 5 is formed between the surface 801a and the surface 801a.

Next, the strong pressure portions 60, 61 of the pressing device are operated in the direction of arrow B1 to apply strong pressure in the axial direction of the crankshaft material 800. Then, the pin 803 and the journal 801 are plastically deformed and compressed in the axial direction.
As a result, the space between the counterweights 805 is narrowed, and the side surface 805a of the counterweight 805 is inserted into the insertion portion 3.
The surface portion 30 of the.

At this time, since the counterweight 805 is strongly pressed in the thickness direction thereof, the draft formed on the side surface 805a of the counterweight 805 is also strongly pressed in the thickness direction, and therefore the magnitude of the draft is small. Therefore, the weight balance of the counterweight 805 can be improved. Further, in this embodiment, since the insertion portion 3 has rigidity, the end face 31 and the surface portion 30 of the insertion portion 3 restrain the deformation of the counterweight 805 when the interval between the counterweights 805 is narrowed. The effect of being able to maintain the accuracy of the shape and size of the weight 805 in good condition is obtained. At this time, the counterweight 805 is also slightly molded (corrected), so the accuracy of the counterweight 805 can be further improved.

In this embodiment, since the end surface 31 of the insertion portion 3 is close to the outer peripheral surface 801a of the journal 801, the outer peripheral surface 801a of the journal 801 is inserted even if the journal 801 is deformed in the direction of increasing the diameter. Since it is restricted by the end surface 31 of the portion 3, it is advantageous to maintain the accuracy of the axial center of the journal 801. (Other Embodiments) In the above embodiment, the interval between the counterweights is narrowed after the twisting process. However, the present invention is not limited to this, and when the twisting process is not performed, after the deburring process, The interval between the counter weights may be narrowed immediately.

FIG. 2 shows an essential part of the second embodiment of the present invention.
Also in this example, as shown in FIG. 2, the insertion portion 3 is inserted between the counterweights 805 facing each other. The sliding surface 32 of the insertion portion 3 is tapered, and the sliding surface 21 of the positioning member 2 is also tapered. Then, when the positioning member 2 moves in the arrow C1 direction, the position of the insertion portion 3 can be adjusted in the same direction. Also in this example, when the insertion portion 3 moves in the axial direction of the crankshaft member 800, the sliding surface 32 of the insertion portion 3 is along the sliding surface 21 of the positioning member 2, that is, perpendicular to the paper surface of FIG. Slide in the direction.

If the period of use is long, the sliding surface 32 of the insertion portion 3 and the sliding surface 21 of the positioning member 2 will be worn during such sliding. Such wear causes the positioning member 2 to be displaced from its normal position, which causes the outer peripheral surface 803 of the pin 803 of the crankshaft material 800 to be displaced.
The size of the gap 5 between the a and the end surface 31 of the insertion portion 3 and the size of the gap 5 between the outer peripheral surface 801a of the journal 801 and the end surface 31 of the insertion portion 3 vary.
In this regard, in this embodiment, if the positioning member 2 is displaced in the direction of the arrow C1, the position of the insertion portion 3 can be adjusted in the same direction.
The thickness of the gap 5 can be adjusted, and fluctuations in the gap 5 can be dealt with.

FIG. 3 shows an essential part of the third embodiment of the present invention.
This example has basically the same configuration as the embodiment shown in FIG. 1 and has the same effects as the first embodiment. However, the outer peripheral surface 80 of the journal 801 of the crankshaft material 800
The end surface 31 of the insertion portion 3 facing the 1a is a journal 80.
The outer surface 801a of the first contacting or approaching the outer surface 801a of the journal 8
No. 01 is restrained, so that the crankshaft material 8
The accuracy of the journal 801 is secured by suppressing abnormal deformation of the journal 801 when the 00 is strongly pressed in the axial direction.

FIG. 4 shows an essential part of the fourth embodiment of the present invention.
In this example, a fluid storage chamber 18 is formed in the base 1, and the fluid storage chamber 18 is loaded with a fluid 19 such as sand and carbon powder particles heated to a predetermined temperature range together with the crankshaft material 800. Has been done. Then, the pressing portion 17 is operated in the arrow E1 direction to compress the fluid 19. In that state, the pressing portions 60 and 61 of the pressing device are operated in the direction of arrow B1 to press the crankshaft member 800 in the axial direction thereof. Then, the pin 803 and the journal 801 of the crankshaft material 800 are plastically deformed and compressed in the axial direction. As a result, the counterweight 80
The interval between 5 is narrowed. Crankshaft material 800
Is in a hot state, the fluid 19 such as sand or carbon powder can be heated to a predetermined temperature, for example, about 200 to 900 ° C.

Since carbon powder is electrically conductive, the carbon powder is charged in a container of another system having an electrode section.
It is also possible to energize the carbon powder or granules through the electrode portion to generate heat at a predetermined temperature for use. By the way, in each of the above-described embodiments, the case where the pin 803 is applied to the crankshaft member 800 spaced at 120 degrees in the circumferential direction is applied. Not only this, as can be understood from FIG. 6 showing the state after cutting,
Of course, the present invention may be applied to the crankshaft 900 provided with the pins 903, the journal 901 and the counterweight 905 which are arranged at intervals of 180 degrees in the circumferential direction. Further, in the above-mentioned embodiment, the invention is applied to the crankshaft of the internal combustion engine, but it is needless to say that it may be applied to the crankshaft used for various engines such as the external combustion engine, and the pin interval is 90. Degrees or other angles are acceptable.

[0026]

According to the method of the present invention, it is possible to provide a crankshaft in which the interval between counterweights is narrowed.
Therefore, it can contribute to downsizing and weight reduction of an engine such as an internal combustion engine. According to the device of the present invention, since the insertion portion moves with respect to the base portion when the interval between the counterweights is narrowed, the interval between the counterweights can be satisfactorily narrowed. Further, when the insertion portion has rigidity, the deformation of the counterweight is regulated by the insertion portion when the interval between the counterweights is narrowed, so that the shape and size of the counterweight can be maintained well.

[Brief description of drawings]

FIG. 1 is a sectional view of an apparatus according to a first embodiment.

FIG. 2 is a cross-sectional view of the device according to the second embodiment.

FIG. 3 is a sectional view of an apparatus according to a third embodiment.

FIG. 4 is a sectional view of a device according to a fourth embodiment.

FIG. 5 is a perspective view of a crankshaft.

FIG. 6 is a perspective view of another crankshaft.

[Explanation of symbols]

In the figure, 1 is a base portion, 2 is a positioning member, 3 is an insertion portion, 4 is a spring member, 5 is a gap, 800 is a crankshaft material, and 8 is a crankshaft material.
01 is a journal, 803 is a pin, and 805 is a counter weight.

Claims (2)

[Claims] 1. A molding process for molding a metal crankshaft material comprising a journal having a shaft core, at least one pin arranged at a predetermined distance in the circumferential direction of the shaft core, and a plurality of counterweights. And a pressurizing step of narrowing the interval between at least two counterweights facing each other by strongly pressing the crankshaft material in the axial direction thereof. .. 2. A base portion on which a crankshaft material is arranged, and a plurality of insertion portions which are arranged on the base portion so as to be movable in the axial direction of the crankshaft and which are inserted between counterweights facing each other. A crankshaft manufacturing apparatus, characterized in that the thickness of each of the insertion portions is smaller by a predetermined value than the distance between the counterweights facing each other whose distance should be narrowed.