JPH08337822A - Method for quenching crank shaft and quenching device - Google Patents

Abstract

PURPOSE: To simplify the producing process of a crank shaft by controlling energy quantity for quenching according to a rotating position of the crank shaft. CONSTITUTION: While rotating the crank shaft, its journal 1J part or its pin part 1P is quenched by high-frequency using a coil 5. The rotating position of the crank shaft is detected by using a measuring instrument 10 and a rotation angle sensor 11, etc. In an arithmetic unit 12, a signal from the measuring instrument 10 and a signal from the rotation angle sensor 11 are treated to calculate how much there is a shift in any direction of the crank shaft. Then, the energy quantity for the quenching is controlled according to the rotating position of the crank shaft so that the bending quantity of the shaft becomes min. By this method, the process for removing the bending can be unnecessitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for quenching a crankshaft of an automobile engine.

[0002]

2. Description of the Related Art A crankshaft of an engine is located between a plurality of pin portions supporting a number of piston rods corresponding to the number of cylinders and two pin portions, and the rotation of the crankshaft itself is mediated by this portion by the engine body. And a journal portion that is rotatably supported. In this case, the journals are rotatably supported by the engine body such that the rotary shafts of all the journal parts are common shafts. The journal portion and the pin portion are separated from each other by a predetermined distance, and their central axes are kept in parallel relationship with each other. The journal portion and the pin portion are connected by a crank arm, and the crank arm is appropriately provided with a counter weight. In the final manufacturing process of this crankshaft, the journal portion and the pin portion are induction hardened in order to improve wear resistance. JP-A-1-
Japanese Patent No. 319633 discloses a structure in which, in the induction hardening process of a crankshaft, induction hardening is performed corresponding to the rotational position of the crankshaft so that the hardening depth is uniform.

After the hardened layer is formed on the journal portion and the pin portion by this quenching, the bending of the crankshaft is corrected so that the central axes of the respective journal portions are precisely aligned, and then the final product is obtained. Get the crankshaft. That is, in the conventional crankshaft manufacturing method, the quenching process for improving the wear resistance of the journal part and the pin part and the bending for ensuring the high finishing accuracy of the crankshaft as the final product are corrected. It was carried out separately from the process.

[0004]

[Problems to be Solved] However, performing the quenching step and the bending correction step separately complicates the manufacturing process, and if these steps can be combined and performed in a single step, It is possible to efficiently perform crankshaft manufacturing, which can simplify the manufacturing process. The present invention is configured in view of such circumstances, and in the manufacturing of the crankshaft, the quenching process and the bending correction process of the crankshaft are combined into a single process, whereby the manufacturing process of the crankshaft is performed. The purpose is to simplify and improve efficiency.

[0005]

In order to achieve the above object, the present invention is a method for induction hardening a journal portion of a crankshaft while rotating the crankshaft, which comprises rotating position of the crankshaft. Is detected and the amount of energy for quenching is controlled according to the rotational position of the crankshaft, and the amount of energy is controlled so that the amount of bending of the crankshaft is minimized. In order to achieve the object of the present invention, it is not necessary to control a plurality of journal parts provided on the crankshaft only for the purpose of correcting the bending of the crankshaft, and at least some of the journal parts are burned. It is also possible to achieve the intended purpose by applying the insert. In a preferred mode, the amount of bending of the crankshaft is detected before quenching, and the amount of energy is controlled based on the amount of bending. Further, the bending of the crankshaft is corrected by changing the quenching depth at the journal portion or the pin portion of the crankshaft in the circumferential direction (axial rotation direction).

Further, the bending of the crankshaft is corrected by changing the quenching depth of the fillet portion in the journal portion or the pin portion of the crankshaft in the circumferential direction. Further, in another aspect, a map that gives a relationship between the bending amount of the crankshaft and the energy amount is provided, and the energy amount may be determined based on the map. When the crankshaft is for a four-cylinder engine, it is preferable to adjust the amount of bending of the crankshaft by induction hardening the first to fifth journals of the crankshaft. According to another aspect of the invention, there is provided an apparatus for induction hardening the journal portion of a crankshaft. A quenching device for a crankshaft according to the present invention includes a rotational position detecting means for detecting a rotational position of a crankshaft, a rotating means for rotating the crankshaft, and a quenching for induction hardening the journal portion of the crankshaft. A quenching means and a control means for controlling the energy amount of the quenching means according to the rotational position of the crankshaft are provided, and the control means controls the energy amount so that the bending amount of the crankshaft is minimized. It is characterized by having come to control.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventor has found that a certain bending phenomenon occurs in a crankshaft during a quenching process in order to obtain a hardened layer on a surface portion of a journal portion and a pin portion of the crankshaft. discovered. Then, it has been found that there is a correlation between the bending amount and the amount of quenching energy added to the journal portion, and the amount of bending of the crankshaft can be controlled by appropriately adjusting the quenching energy. When quenching a crankshaft, place a high-frequency quenching coil close to the journal and pin to be quenched, and while the crankshaft is rotating, input high-frequency waves into the relevant section to generate heat and melt. Then, by performing a predetermined cooling operation, a hardened layer having a predetermined quenching depth is formed on the surface portions of the journal portion and the pin portion. In this case, since the rotational position of the crankshaft is constantly monitored, the quenching energy amount is set according to this rotational position. As described above, the amount of energy, the bending direction of the crankshaft, and the amount of bending have a constant correlation. Therefore, by controlling the amount of quenching energy at a predetermined angular position of the crankshaft, the crankshaft in that angular direction can be controlled. The amount of bending can be controlled.

As described above, in the preferred embodiment, data giving the relationship between the energy amount, the bending amount of the crankshaft, and the directionality of the bending is previously obtained by experiments or the like. This relationship is usually stored in the memory (ROM or the like) of the control device in the form of a map, and the energy amount can be obtained by knowing the rotational angle position of the crankshaft and the bending amount to be corrected.
The input power to the coil of the induction hardening apparatus is set so that the calculated energy amount is obtained. Then, this amount of electric power is supplied to the induction hardening coil corresponding to the rotational position of the crankshaft. This makes it possible to control the amount of bending of the crankshaft in a specific direction. In this way, in the quenching process, it became possible to precisely control the amount of bending of the crankshaft, which eliminates the need for an independent process for correcting the amount of bending in the past, and promotes the efficiency of the manufacturing process of the crankshaft. it can.

[0009]

Embodiments of the present invention will be described below. Referring to FIG. 1, there is shown a schematic configuration diagram of a crankshaft quenching apparatus 1 according to the present invention. 2 and 3 are schematic diagrams showing the holding structure of the crankshaft quenching device, particularly the holding structure of the crankshaft 2 and the arrangement state of the high-frequency applying coil. The crankshaft 2 of FIG. 2 is for a four-cylinder engine, and has four pin portions 1P and 2P that rotatably support connecting rods (not shown) that connect pistons corresponding to each cylinder. ,
It is equipped with 3P and 4P. Further crankshaft 2
The journal portions 1J, 2J, 3J, 4J and 5J are formed between the respective pin portions 1P, 2P, 3P and 4P, and the crank portions are connected through the journal portions 1J, 2J, 3J, 4J and 5J. The shaft 2 is rotatably supported by the engine body. A crank arm portion 2a connects between each pin portion and the journal portion,
The central axis of the pin portion and the central axis of the journal portion have a predetermined distance and are maintained in parallel relationship with each other. Further, the crank arm 2a is provided with a counterweight 2b so as to balance with the pin portion.

A flywheel (not shown) is attached to the tip of one journal portion of the crankshaft 2,
The engine output is taken from this end. The first journal 1J portion and the fifth journal portion 5J at both ends of the crankshaft 2 are gripped and fixed by the chucks 3a and 3b from both sides. The chuck is the rotary shaft member 4
The crankshaft 2 is attached to the tips of a and 4b and rotates while holding the crankshaft 2 by a power source such as a motor (not shown). In this case, the crankshaft 2 is set to rotate in the same state as when mounted on the engine. That is, the crankshaft 2 is positioned so that the rotary shafts of the rotary members 4a and 4b and the rotary shaft of the crankshaft 2 coincide with each other, and the chucks 3a and 3b are positioned.
Is gripped by. Above the crankshaft 2 gripped in this way, an electromagnetic coil 5 for applying a high frequency to the journal part and the pin part to heat and melt the surface is arranged. The coil is arranged so as to be suspended from above by the chain 6 so as to correspond to the respective journal portions forming the quench-hardened layer and the pin portions. Then, as shown in FIG. 2, the journal portions 1J, 2J, 3 of the crankshaft 2 are
J, 4J and 5J or pin parts 1P, 2P, 3P and 4
Around the P, guide tips 7, 8 and 9 are arranged at intervals in the circumferential direction of the journal portion or the pin portion, the chain is loosened, and the coil is attached to the crankshaft to a predetermined position. At this time, it is positioned at a predetermined position with respect to the part of the crankshaft which should be hardened by hitting the guide tip.

The crankshaft 2 has chucks 3a and 3b.
When the crankshaft 2 is not bent in a state that it is clamped in, all the journal parts 1J, 2J,
3J, 4J and 5J have a single axis of rotation,
All pin parts 1P, 2P, 3P and 4P should have the same swivel trajectory. However, in actual crankshafts, the axis of the journal portion is usually slightly deviated at the time of manufacture, and conventionally, a step of correcting the axis deviation of the journal portion was provided after the quenching step of the crankshaft. In this example, when the crankshaft 2 is gripped by the chucks 3a and 3b in the above-described state, the power source is activated to rotate, and the measuring device 10 causes the rotational deviation and the deflection of each journal portion. , Detect bends.
In addition, the measuring device 10 is provided with pin portions 1P, 2P, 3P, 4P.
It may be arranged to detect the shake of the. Since each journal portion is finished so as to have a perfect circular outer shape, the outer shape line does not change when there is no axial deviation. However, if the central axis of the journal portion is deviated from the rotation axis of the crankshaft 2 which is held by the chuck and rotates, the outer shape of the journal portion is blurred due to the rotation of the journal portion. In this example, the measuring device 10 measures the maximum deviation of the contour line when the journal portion rotates, and corrects the deviation of the crankshaft 2 through the quenching process so that the deviation does not occur. There is.

FIG. 1 is a schematic block diagram of a quenching apparatus having a function of correcting the bending of a crankshaft 2 according to an embodiment of the present invention. The quenching apparatus of the present example receives the data of the deviation amount of the journal portions 1J, 2J, 3J, 4J and 5J of the crankshaft 2 caused by the rotation from the measuring instrument 10, that is, the bending amount of the crankshaft, An arithmetic device for processing this is provided. Further, a rotation sensor 9 for detecting the rotation angle of the crankshaft is provided, and a signal from this rotation sensor is also input to the arithmetic unit 12. In the arithmetic unit 12,
The signal from the measuring instrument 10 and the signal from the rotation angle sensor 11 are processed to calculate in which direction of the crankshaft and how much the shift is present. Further, the quenching apparatus of this example is provided with an electromagnetic coil 5 whose high-frequency power generation amount is adjusted by a signal from the arithmetic unit 12, and the electromagnetic coil 5 is not shown via the wiring 14. Connected to power supply.

The control of the quenching apparatus 1 of this example will be described below. FIG. 4 shows a schematic flowchart of control of the quenching device. The arithmetic unit 12 first detects the axial shift amount of the crankshaft, that is, the bending amount of the crankshaft, as described above. In this case, the direction and amount of the axis deviation are detected by processing the signal from the rotation sensor. Next, the arithmetic unit 10 determines the amount of electric power for quenching required to correct the above-mentioned misalignment. In this case, in this example, experimental data indicating the correlation between the quenching operation and the axial deviation, that is, the amount of bending of the crankshaft 2 that accompanies this operation is provided in advance, and this data is used to detect the above. When there is a bend (initial bend), in light of the above experimental data,
Quenching is performed so as to cancel out the above-mentioned initial rolling by positively utilizing the bending (quenching bending) that is inevitably generated with the hardening operation. This quenching bend is caused by the quenching portion 1 shown by the hatched portion in FIG.
3 is caused by changing the quenching depth in the circumferential direction (around the axis) in the journal portion 1J, 2J, 3J, 4J or 5J or the pin portion 1P, 2P, 3P or 4P and the fillet R portions at both ends thereof. I was known this time. That is, since the volume of the quenched structure is larger than that of the normal non-quenched structure, the crank arm portion 2a is changed by changing the quenching depth in the circumferential direction of the pin portion or the journal portion.
Angle between the pin and the journal,
By utilizing this change in angle, the bending of the crankshaft is corrected. In particular, as shown in FIG. 5, the crank pin portion or the journal portion has a fillet portion R which is curved in the radial direction on its side portion, and the crank arm portion is changed by changing the quenching depth of the fillet portion in the circumferential direction. An angle change occurs between 2a and the crank pin portion or the journal portion, and the bending of the crankshaft 2 can be corrected by utilizing this angle change.

In FIG. 5, the pin portion 1P will be described as an example. In the fillet R _1P in the pin portion _1P , when the upper (top) quenching depth in FIG. 5 is made larger than the lower (bottom) quenching depth, Bending occurs so that the journal portions of the crank arms 2a on both sides approach each other. Therefore, by controlling the amount and direction of quenching bending by measuring the initial bending and adjusting the amount of power to the quenching electromagnetic coil 5,
The quenching process can be performed so that the bending of the final product of the crankshaft 2 is minimized. For this purpose, in this example, the direction and amount of bending as shown in FIG. 6 or FIG. 7 and the ratio of the depth of quenching between predetermined angles of the quenching portion, or the energy input to the coil are used. A graph showing the relationship is stored as a map in the memory of the arithmetic unit. For example, in FIG. 8, 0 ° and 1
The relationship between the ratio of the quenching depth and the bending at the crankshaft angular position of 80 ° is the relationship between the input energy to the coil and the bending at θ1 and θ2 having the respective angular ranges shown in FIG. 8 in FIG. It is shown.
In FIG. 6 and FIG. 7, the vertical axis indicates the amount of bending toward the second and third pin portions, and the amount of bending toward the first and fourth pin portions is upward. . Therefore, it can be seen that by giving the ratio of the energy input to the quenching in this direction, the state of bending within the area range shown by the diagonal lines in the figure occurs.

In the present embodiment, the relationship between the bending and the input energy at a predetermined crankshaft angular position stored in the arithmetic unit 12 is determined in light of the detected value based on the amount and the direction of the initial bending, and the coil is detected. 5
Determine the amount of power. Next, the arithmetic unit 12 supplies the coil 5 with a signal according to the determined electric energy. In the quenching process, the crankshaft 2 is heated by a coil 5 while being rotated, so that the surface of the crankshaft 2 is heated. Then, the crankshaft 2 is quenched by cooling water or oil for quenching. In this case, for example, in FIG.
In the region indicated by θ1, the energy input to the coil is reduced as compared with the region indicated by θ2. As a result, the bending of the quenching is caused by the crank arms 2 on both sides of the quenching part.
Since a occurs so as to approach a, it is possible to effectively remove the initial bend when the initial bend is open beyond the predetermined position. The crankshaft 2 is designed to rotate a predetermined time during the heating time by energizing the coil 5, and the journal portion 1J (2J, 3J, 4J or 5J) or pin which is the target of the quenching bending control described above. In the portion 1P (2P, 3P or 4P), the amount of electric power to the coil 5 is changed and controlled as described above within a predetermined crank angle range.

Next, in the quenching device, after the coil 5 has been de-energized, the heating part 8 is cooled with water or oil so that a predetermined temperature gradient is obtained, and quenching is performed in this cooling step. After that, the final crankshaft 2 is obtained. Whether to change the quenching input energy to produce a quench bend depends on the presence of the initial burr. In this way, it is not necessary to change and control the energy input to the coils in all quenching processing parts, and it is not necessary to control the elimination of the initial bending only by controlling the hardening part in which the bending exists. Good. That is, although the initial bending is performed in the journal portion, the control of the quenching bending for correcting the initial bending, that is, the control of the electric power amount to the coil can be performed through the journal portion or the pin portion. As such control amount, the quenching depth or the amount of electric power as shown in FIG. 6 or FIG. 7 and the direction and amount of bending in a specific journal portion are obtained in advance by experiments, and this is calculated. It can be determined by storing it.

In the above example, the case was shown based on the experimental data in the vertical direction of the crankshaft, that is, in the 0 ° and 180 ° directions, but the experimental data was created and placed at various angular positions. More accurate bending correction control in the insertion process can be performed. Further, in the above example, the electric energy is controlled so as to be changed corresponding to the angular position of the crankshaft, but quenching is performed by changing the rotational speed of the crankshaft corresponding to the angular position of the crankshaft. It is also possible to control the depth, that is, the amount of bending of the crankshaft, and in this case, it is not necessary to change and control the amount of electric power of the coil.

[0018]

As described above, according to the present invention, it is possible to correct the axial deviation or bending which is inevitably generated in the crankshaft in the quenching step, so that a special step for removing the bending is provided. There is no need.
Therefore, the manufacturing process of the crankshaft can be simplified, and the crankshaft can be efficiently manufactured.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a quenching device according to an embodiment of the present invention,

FIG. 2 is a front view showing a grasped state of a crankshaft,

FIG. 3 is a side view showing a grasped state of a crankshaft,

FIG. 4 is a flowchart showing a quenching process of a crankshaft,

FIG. 5 is a cross-sectional view showing a hardened hard layer of a pin portion of a crankshaft,

FIG. 6 is a graph showing the relationship between the bending and direction of the crankshaft and the ratio of quenching depth,

FIG. 7 is a graph showing the relationship between the bending and direction of the crankshaft and the ratio of the energy input to the coil.

FIG. 8 is a graph showing a relationship between an angular position of a crankshaft and energy input to a coil.

[Explanation of symbols]

 1 quenching device, 2 crankshaft, 3 chuck, 4 rotating shaft member, 5 coil, 10 micrometer, 11 rotation angle sensor, 12 arithmetic unit, 13 quenching part, 14 wiring.

Claims (8)

[Claims] 1. A method of induction hardening a journal portion of a crankshaft while rotating the crankshaft, comprising detecting a rotational position of the crankshaft and determining an energy amount of the hardening to rotate the crankshaft. A method for quenching a crankshaft, comprising a step of controlling according to a position to control the amount of energy so that a bending amount of the crankshaft is minimized. 2. The quenching for controlling the energy amount according to claim 1, wherein at least a part of a plurality of journal portions or pin portions provided on the crankshaft is hardened to control the energy amount. The method of quenching the crankshaft is characterized by the fact that 3. The quenching of a crankshaft according to claim 1, wherein the amount of bending of the crankshaft is detected before quenching, and the amount of energy is controlled based on the amount of bending. Method. 4. A method for quenching a crankshaft according to claim 3, wherein the quenching depth at the journal portion or the pin portion of the crankshaft is changed in the circumferential direction. 5. The method for quenching a crankshaft according to claim 3, wherein the quenching depth of the fillet portion in the journal portion or the pin portion of the crankshaft is changed in the circumferential direction. 6. The map according to claim 1, further comprising a map that gives a relationship between the amount of bending of the crankshaft and the amount of energy, and the amount of energy is determined based on the map. How to quench the crankshaft. 7. The crankshaft for a four-cylinder engine according to claim 1, wherein the amount of bending of the crankshaft is adjusted by induction hardening of the first to fifth journals of the crankshaft. Characteristic crankshaft quenching method. 8. A device for induction hardening a journal portion of a crankshaft, comprising: a rotational position detecting means for detecting a rotational position of the crankshaft; a rotating means for rotating the crankshaft; The journal unit includes a quenching unit that applies induction hardening, and a control unit that controls the energy amount of the quenching unit according to the rotational position of the crankshaft. The control unit controls whether the crankshaft bends. A crankshaft quenching device, characterized in that the amount of energy is controlled so as to be minimized.