JP3537566B2 - Precision induction quenching method and apparatus for cylinder block - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a case where a quenched layer which is partially divided is formed on the inner surface of a cylinder used under a high load such as a cylinder block of a diesel engine. The present invention relates to a precision induction quenching method and apparatus for performing induction quenching by precisely controlling the position of an induction heating coil.

[0002]

2. Description of the Related Art For example, on the inner surface of a high-load cylinder such as a diesel engine, as shown in FIG.
Inner quenching to form 6a is performed. The applicant has previously proposed an induction heating coil and an induction quenching method described in JP-A-7-161461 and JP-A-7-272845 with respect to the inner surface quenching of such a cylinder block. The present invention uses an induction heating coil composed of an inductor having a recess formed partially on the inner periphery of a cylindrical portion of an inductor formed of a substantially cylindrical dielectric member shown in FIG. While moving in the direction of the cylinder axis at a constant interval in the inner diameter, and generating an induction current while indexing at a constant rotation angle, the inner peripheral portion of the cylinder facing each recess of the inductor is divided and heated, and the inside of the cylinder is heated. A plurality of quenched portions in a checkered pattern are formed around the circumference as shown in FIG.

[0003] In order to mass-produce the induction quenching, the applicant has disclosed in Japanese Patent Application No. 7-49337 the following method to form an even quenched layer in the checkered quenched portion. An internal hardening device for the cylinder block that can be mass-produced is proposed. That is, the cylinder block inner surface hardening device measures the center position of the cylinder bore of the cylinder block by the position measuring means after placing the cylinder block in the cooling liquid tank on the XY table provided on the base frame. The control means drives the XY table based on the measured value signal to make the center of the cylinder bore coincide with the center of the induction heating coil. After the center of the cylinder bore coincides with the center of the induction heating coil, cooling is performed in the cooling liquid tank. The liquid is injected, the block is immersed in the cylinder block, and the portion to be quenched is immersed in the induction heating and quenched and quenched.

In the case of quenching using the induction coil of the invention described above, if there is a deviation in the gap between the inner diameter of the cylinder and the outer diameter of the induction heating coil, the heating temperature of the quenched part differs, and the shape of the quenched pattern in each part of the circumference becomes uneven. Occurs and the depth of the quenched layer also becomes shallow. Therefore, in order to accurately form the above-mentioned checkered partial quench hardened portion 76a, for example, in the case of internal diameter quenching with a cylinder diameter of 80 mmφ, the gap is set to 1.25 mm ± 0.15 mm and the heating coil and the cylinder It has been experimentally confirmed that the center of the cylinder and the induction heating coil must be precisely set so that the deviation of the center of the cylinder becomes 0.03 mm or less. According to the inner hardening device for a cylinder block of the present invention, this accuracy can be easily obtained in mass production.

On the other hand, water or an aqueous solution is used as a coolant for quenching. However, when water or an aqueous solution is used as a cooling liquid, if the liquid temperature is too low, quenching cracks occur during quenching, and if the liquid temperature is too high, the cooling capacity is reduced and sufficient quenching hardness cannot be obtained. Therefore, the temperature of water or an aqueous solution (hereinafter, referred to as a cooling liquid) is usually maintained at 30 to 40 ° C.

[0006]

However, in the internal hardening apparatus for a cylinder block according to the above invention, if the hardening is performed using a coolant having a temperature higher than room temperature as described above, the temperature of the apparatus increases and the temperature of the apparatus increases. Due to the thermal expansion of the base frame, there is a problem in that the measured value fluctuates from the initial value measured by the position measuring means and shifts, so that precise hardening cannot be performed.
That is, at the beginning of the work, the entire quenching apparatus is at room temperature, but if the cooling liquid at 30 to 40 ° C. higher than room temperature is injected or discharged into the cooling liquid tank every time quenching as described above,
The heat causes the temperature of the base frame to rise, and the distance between the position measuring means and the induction heating coil fluctuates. The value calculated by the control means from the numerical value measured at room temperature at the start of work is XY. Even if the table is driven, the center of the cylinder bore and the center of the induction heating coil are displaced, and the gap between the cylinder diameter and the induction heating coil is deviated, resulting in unevenness in the checkered quenched portion. Occurred.

[0007] As a countermeasure, it is conceivable to incorporate a deviation value in a state where the temperature has risen in advance in the control means and wait for the above-mentioned positional deviation to become constant before performing the quenching operation. However, it takes a considerable time for the temperature of this device to rise, and in winter, etc., it takes 30 to 30 minutes.
It takes time and effort to inject and discharge the cooling liquid heated to 40 ° C. into and out of the cooling liquid tank, so that the temperature of the apparatus is evenly increased. Also, in order to solve the above drawbacks, such as placing the quenching device in a constant temperature chamber,
Although there is a method of providing a chiller for precisely controlling the temperature of the cooling liquid, there is a disadvantage that a large amount of equipment cost is required.

Therefore, the present invention provides a precision induction hardening method and apparatus which can easily and economically reduce a change in the center position of a cylinder bore and an induction coil and enable uniform hardening of the checkered quenched layer. The purpose is to provide.

[0009]

In order to achieve the above object, a method for precision induction hardening of a cylinder block according to the present invention comprises:
Coolant tank for holding cylinder block immersed in liquid
And the cooling liquid tank can be placed and moved in the X and Y directions respectively.
XY table and cylinder block cylinder
Position measuring means for measuring the center position of the dowel, and a cylinder
An induction heating coil for induction heating the inner surface;
The cylinder bore of the cylinder block is
Before aligning the center with the center of the induction heating coil
Control means for driving the XY table
In the inner quenching device of Dublock, quenching of the quenched body
The part to be quenched is immersed in the cooling liquid of the cooling liquid tank.
Energize the induction heating coil while immersed in the liquid to quench
After heating the part to the quenching temperature, turn on the induction heating coil.
Induction quenching, which is quenched by cutting and quenching
In addition, it is characterized by cooling with a cooling liquid at room temperature and quenching .

That is, as in the prior art, a chamber at 30 ° C. to 40 ° C.
If you use a coolant that is hotter than
The temperature of the frame is room temperature, but it will increase as you work.
As the base frame gradually expands and the base frame expands,
The distance between the fixing means and the induction heating coil varies. Against this
And a coolant at room temperature equal to the temperature of the base frame.
Temperature change of the base frame if used by supplying to the reject tank
Less distance between the position measuring means and the induction heating coil
Fluctuations are small. Therefore, special means such as chillers
Precise induction quenching can be performed without providing a hole.

Further , the cylinder block of the present invention can be precisely guided.
The quenching device holds the cylinder block immersed in the liquid
A cooling liquid tank to be mounted and the cooling liquid tank
A movable XY table and the cylinder block
Position measuring means for measuring the center position of the cylinder bore of the rack
And an induction heating coil for induction heating the inner surface of the cylinder, and
According to the measured value of the position measuring means,
Center the cylinder bore with the center of the induction heating coil
Control means for driving the XY table so that
In the internal hardening device for the cylinder block equipped with
The quenched part of the insert is immersed in the cooling liquid in the cooling liquid tank, and
Through the induction heating coil with the quenched part of
After heating the part to be quenched to the quenching temperature,
Induction quenching by quenching and quenching by cutting off the current
When quenching, cool with room temperature cooling liquid
So that the temperature of the immersion coolant is kept at room temperature
It is characterized by comprising control means.

The temperature of the cooling liquid supplied to the cooling liquid tank as described above
By providing a liquid temperature control means for maintaining the temperature at room temperature,
Precision quenching by cooling with the above room temperature coolant is easily achieved
Can be achieved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. FIG. 1 is a system diagram of a coolant in the precision induction quenching apparatus of the present invention, FIG. 2 is a front view of the precision induction quenching apparatus of the present invention, FIG. 3 is a side view thereof, and FIG. FIG. 5 and FIG. 5 are detailed sectional views of the cooling liquid tank. FIG. 6 is a diagram showing a change in the distance between the position measuring means and the induction heating coil, and FIG. 7 is a diagram showing a variation in dimensions of a quenched portion quenched by the precision induction quenching method of the present invention.

FIG. 8 is a view showing the shape of the inductor of the induction heating coil used in the embodiment of the present invention, and FIG. 9 is a state in which a quenched portion in which a checkered pattern is hardened on the inner surface of the cylinder is clarified by etching. FIG.

The outline of the structure of the precision induction hardening apparatus according to the embodiment of the present invention will be described below with reference to FIGS. In the precision induction quenching apparatus according to the present embodiment, the portal frame 21 is located at the third position on the left side of FIG.
And the movable frame 22 is fixed to the portal frame 2
1 is slidably mounted vertically and is driven to move in the vertical and vertical Z directions by a servo motor driving device 25 driven by a pulse signal sent by a control unit 101 of the control means 100. The control unit 10
1 is fixedly mounted on the movable frame 22 by a pulse signal sent by the
The induction heating coil 23 is axially fixed to the vertical shaft 24, and is driven to rotate forward and reverse.

In the induction heating coil 23 used in the embodiment of the present invention, as shown in FIG. 8, the inductor 70 is partially recessed at an equal angle in the circumferential direction of the inner peripheral wall of the cylindrical dielectric member 71.
Are formed, and twelve checkered partial quenching layers 76a are formed on the inner peripheral wall 76 of the cylinder 75 facing each recess 74 by induction heating.
The induction heating coil 23 is supported by the vertical shaft 24 about the center of the cylindrical dielectric member 71 of the inductor 70 as described above, and is held by the movable frame 22 via the driving device 26 so as to be vertically movable. The induction heating coil 23 is moved downward by a signal from the control unit 101 and inserted into a cylinder bore of a cylinder block (hereinafter referred to as a work block) W to be quenched. After forming the quenched layer of the pattern, a plurality of rows of quenched portions can be formed by repeating the operation of moving by a fixed distance in the vertical axis Z direction, indexing a fixed rotation angle, rotating and induction heating.

A support frame 31 is provided straddling the base frame 11 above a second position substantially near the center of the base frame 11 in the X direction of FIG. A driving device 34 driven up and down by a signal is fixedly provided. A Marposs measuring device (four-needle inner diameter measuring device manufactured by Marposs Co., Ltd.) 32 as a position measuring means is attached below the vertical axis 33 of the driving device 34 so as to move in the vertical Z direction.

An X table 41 is driven on a rail 12 in the X direction on the upper surface of the base frame 11 by a pulse motor 44 driven by a pulse signal sent from the control unit 101 and a ball screw 45. It is designed to be driven back and forth between three positions. A rail 42 is provided in the Y direction (perpendicular to the plane of FIG. 2) of a plane perpendicular to the X axis on the X table 41, and the Y table 43 is driven on the rail 42 by a pulse signal from the controller 101. The drive unit 46 is driven to reciprocate in the Y direction perpendicular to the plane of FIG.

At a position near the third position of the cooling liquid tank 48 on the Y table 43, a reference ring 51 forming a ring body having substantially the same inner diameter as the cylinder bore diameter as a second reference member is fixedly provided. The reference ring 51 is provided such that the ring upper surface is substantially at the same position as the upper surface of the work block W, and the center thereof is substantially the same as the cylinder row of the work block W on the same X-ray with the central axis perpendicular thereto.

The control means 100 shown in FIG.
1 and the storage unit 102. The storage unit 102 stores X-Y in each stage of the preparation stage of the internal hardening of the cylinder block.
The coordinates of the table, the measured value of the coordinates of each cylinder bore of the work block in the quenching stage, and the operating position of the induction heating coil are stored. The control unit 101 determines the X table 41, the Y table 43, the Marposs measuring device 32, the movable frame 22, and the induction heating coil 23 from the coordinate values stored in the storage unit 102 in a preparation step and a quenching step, which will be described later. The driving devices 44, 46, 34,
25 and 26.

A work block W is placed on the Y table 43.
Is provided in a cooling liquid tank 48 in which the liquid is immersed in a cooling liquid.
As shown in detail in FIG. 5, the cooling liquid tank 48 is a box-shaped tank having an open upper surface, and a bottom plate 49 having a hollow portion 49a is provided on the inner bottom portion. W is placed. Then, the coolant is supplied to the pipe 94.
Is supplied to the cooling liquid tank 48 from the same number of ejection holes 49b provided in a portion corresponding to the center position of each cylinder bore through the hollow part 49a, through the cylinder inner diameter part, and the cooling liquid tank 48 is emptied. A large amount of liquid is sent from the state of (1) until the liquid becomes full, and when the liquid becomes full, a small amount of liquid is supplied so as to maintain the liquid level in the tank. Also, during the quenching, a fixed amount of cooling liquid is injected and flows out from an overflow pipe 83 provided on the side surface of the cooling liquid tank 48. Thereby, the cooling liquid tank 4
The liquid level of No. 8 is kept constant. A plurality of discharge pipes 81 provided with valves 82 are provided on the bottom surface of the cooling liquid tank 48 (only one is shown in the figure). When the quenching is completed, the valve 82 is opened to rapidly discharge the cooling liquid and the next work is performed. Blocks can be quickly replaced.

A cavity is formed inside the base frame 11, and a box-shaped frame tank 85 long in the longitudinal direction of the frame is housed in the cavity so as to be insulated from the base frame 11. The upper part of the frame tank 85 is opened, and receives the cooling liquid discharged from the discharge pipe 81 and the overflow pipe 83 of the cooling liquid tank 48 even while the cooling liquid tank 48 is running on the XY table 41 in the X and Y directions. It is supposed to be. As shown in the system diagram of FIG. 1, the cooling liquid discharged to the frame tank 85 flows out to a liquid receiving tank 87 via a pipe 86, and the cooling liquid discharged to the liquid receiving tank 87 is supplied to a pipe 88. , A pump 89 and a pipe 90 to a liquid storage tank 91. The liquid storage tank 91 is provided with a heat exchanger 95 for cooling with cooling water sent through a pipe 96, and cools the cooling liquid stored in the liquid storage tank 91 so as to maintain room temperature. The method of maintaining the liquid temperature by the heat exchanger 95 is generally used and has no special features, but is economical because the heat exchanger 95 does not require a refrigerator or the like and is sufficient with ordinary-temperature industrial water. . The coolant stored in the storage tank 91 is supplied to the pipe 92, the pump 93, and the pipe 94.
Is supplied to the cooling liquid tank 48 through the cylinder, and is injected into the cooling liquid tank 48 through the inner diameter of the cylinder of the work block.

The work block W is heated by induction through the induction heating coil 23 while being immersed in the cooling liquid in the cooling liquid tank 48, and when the current of the induction heating coil is cut off.
It is cooled by the immersion coolant and quenched.

The operation of the precision induction quenching apparatus having the above configuration will be described below as an example in which a four-cylinder cylinder block having a cylinder bore diameter of 80 mm and a cylinder interval of 105 mm is quenched. This operation includes a preparation step for setting the positions of the cylinder bore and the induction heating coil and a quenching step. First, as a preparation stage, the XY table is moved so that the reference ring 51 is at the second position,
The center of the reference ring 51 is made to coincide with the center of the Marposs measuring device 32. At this time, the coordinates Xo, Yo of the XY table
Is set to 0 points. The coordinates Xo and Yo are mainly used for correcting the table position at the beginning of the operation.

Next, the coordinates of the center of the first cylinder bore M1 of the master block M having the same shape as the separately prepared work block W are determined in the XY table. First, the master block M is placed in the cooling liquid tank, and the XY table is moved so that the first cylinder bore M1 comes to the second position. First
A point at which the center of the cylinder bore M1 coincides with the center of the Marposs measuring device 32 is detected, and its coordinates are defined as X1 and Y1.
The center dimension of the cylinder bore of the master block M is 1 at equal intervals
Since it is mechanically machined to a size of 05 mm, the coordinates of each cylinder bore below the second cylinder bore M2 are: the position coordinates of the first cylinder bore: X1, Y1, the position coordinates of the second cylinder bore: (X1 + 105), Y1, The position coordinates of the three cylinder bore: (X1 + 210), Y1, and the position coordinates of the fourth cylinder bore: (X1 + 315), Y1, are stored in the storage unit 102.

Next, the relative position coordinates between the induction heating coil 23 and the XY table are determined. The XY table 40 is shown in FIG.
Is moved to the third position on the right side of the drawing, the center of the first cylinder bore M1 of the master block M is made to coincide with the center of the induction heating coil 23, and the coordinates of the coincidence point of the center in the XY table are set to X
The data is stored in the storage unit 102 as p and Yp. When the above operation is completed, the XY table is returned to the original first position and X
-Unload the master block M on the Y table. Thus, the preparation stage of induction heating and quenching of the cylinder block is completed.

Next, the operation in the quenching stage will be described. First, in order to set the position coordinates of each cylinder bore of the work block W, the work block W is placed at a fixed position on the XY table. At this time, the position of each cylinder bore of the work block W is located at substantially the same position as each cylinder bore of the master block M described above. However, the positions are slightly shifted due to the accuracy of the mounting and the accuracy of the individual work block processing. It is impossible to perform induction heating and quenching with high precision using the position coordinates of each cylinder of the master block as it is. Therefore, it is necessary to measure the deviation between the position of the master block and the position of the work block. The operation will be described below.

After placing the work block W on the XY table, the control unit 101 of the control unit 100 and the storage unit 102
Drive devices 44 and 46 move the XY table to the positions of coordinates X1 and Y1. Then, the driving device 34
Inserts the Marpos measuring device 32 into the first cylinder bore W1 of the work block W, and detects the eccentricity between the Marpos measuring device 32 and the center of the first cylinder bore W1. That is, the Marpos measuring device 32 calculates the coordinate X of the center of the first cylinder bore M1 of the master block M from the eccentricity value.
The displacement values a1, b1 of the position coordinates of the first cylinder bore W1 of the work block W with respect to 1, 1 are measured, and the coordinates (X1 + a1), (Y1 + b1) are detected. The shift values a1 and b1 are stored in the storage unit 102 of the control unit 100. When the above operation is completed, the control unit 101 controls the Marpos measuring device 32 via the driving device 34 to the first cylinder bore W.
Then, the XY table 40 is driven to raise the position coordinates of the second cylinder bore M2 of the master block:
(X1 + 105), and moves to Y1, and by the same operation as above, the deviation value a2 of the second cylinder bore W2 of the work block W from the second cylinder bore M2 of the master block M.
b2 is measured, the position coordinates of the first cylinder bore W1: (X1 + a1), (Y1 + b1), the position coordinates of the second cylinder bore W2: (X1 + 105 + a2), (Y1 + b2) The position coordinates of the third cylinder bore W3: (X1 + 210 + a3), (Y1 + b3) The position coordinates of the fourth cylinder bore W4 are stored as (X1 + 315 + a4) and (Y1 + b4).

When the position coordinates of each cylinder bore of the work block are determined, a hardening operation is started and the control unit 101
Drives the XY table and changes the coordinate value to (Xp-a1),
The XY table is moved to (Yp-b1). Thereby, the deviation values a1 and b1 of the cylinder position between the master block and the work block are corrected, and the induction heating coil 23 and the first
The center positions of the cylinder bores W1 match. At this position, the induction heating coil 23 is lowered by the
It is inserted into a predetermined position of the cylinder bore W1 and heated by energization.
At this time, since the cooling liquid tank 48 is filled with the cooling liquid, the inner diameter of the first cylinder bore W1 is induction-heated to reach the quenching temperature, and when the power is cut off, it is rapidly cooled by the cooling liquid in the cooling liquid tank. Quenching is performed. The same operation is performed for the first to first
This is performed for the fourth cylinder, and the quenching of all the cylinders is completed. When quenching of all cylinders is completed, valve 8
2 is opened and the coolant in the coolant tank 48 is discharged to the frame tank 85. The coolant is discharged while the coolant tank 48 is running on the XY table in order to shorten the quenching operation time.

The set value measured by the position measuring means and calculated by the control means may be operated with the calculated set value unless the distance between the Marpos measuring device 32 and the induction heating coil 23 fluctuates. However, in practice, the temperature of the machine is low at the beginning of the operation, but the temperature of the machine gradually increases when the operation is started. Therefore, the distance between the Marpos measuring device 32 and the induction heating coil 23 changes due to thermal expansion of the base frame or the like. For this reason, if it is set according to the calculation formula, the center of the induction heating coil 23 and the center of the cylinder bore are displaced to be eccentric, resulting in uneven quenching. Even when the hardening operation is not performed, the distance between the two changes due to thermal expansion of the base frame due to heat generated by the motor. FIG. 6 shows an example of the actually measured value of the change in the distance. A diagram B in FIG . 6 shows a case of idling at a room temperature of 22 ° C. without quenching. As can be seen from the figure, when the idle operation is started, the temperature of the base frame rises, and the distance between the Marposs measuring device 32 and the induction coil 23 gradually increases. When the operation is performed for about 10 minutes, the distance between the two is about 30 μm before the operation. growing. It is saturated at about 30 μm and hardly changes thereafter. When the operation is completed, the temperature of the apparatus decreases, but the rate of the decrease is lower than that at the time of the increase.
It took about 50 minutes for the interval of 3 to return to the value before operation.
However, as described above, if the center deviation between the cylinder bore and the induction heating coil is 30 μm or less, the quenching accuracy is permissible.

The diagram B in FIG . 6 shows the case of the idling operation in which the cooling liquid is not flown . However, when the cooling liquid is flowed for quenching, it is estimated that the amount of change further increases. Therefore,
Set the temperature of the cooling liquid to 32 ° C. (usually 30
-40 ° C.), and repeatedly injected and discharged into the cooling liquid tank, and the change in the distance between the Marpos measuring device 32 and the induction coil 23 was measured in the same manner as described above. The result is shown in diagram A of FIG . As can be seen from the figure, in this case, the interval between the Marposs measuring device 32 and the induction coil 23 increases for 20 minutes after the start of the work, and after approximately 20 minutes, the distance extends to about 100 μm and saturates. From these results, when using a coolant at a temperature of 30 ° C. to 40 ° C., the gap between the cylinder bore and the induction heating coil was set to the above-mentioned allowable value of 1. It was found that the temperature could not be maintained at 25 mm ± 0.15 mm and precise hardening could not be performed.

Next, the temperature of the cooling liquid was set to 22 ° C., which is the same as the room temperature, and injection and discharge into the cooling liquid tank were repeated as described above.
A change in the distance between the Marpos measuring device 32 and the induction coil 23 at this time is shown by a curve C in FIG. In this case, as can be seen from the figure, the change in the interval is almost the same as or slightly smaller than in the case of the idling operation, but it saturates a little later than in the idling operation after about 15 minutes of operation. Was. This is presumed to be the result of suppressing the temperature rise from idling due to the cooling effect of the room temperature coolant. There was no significant difference in the recovery time of the interval after shutdown.

[0033]

From the above results, if the quenching operation is performed with the temperature of the coolant being the same as the room temperature, the gap between the cylinder bore and the induction heating coil can be formed without any special correction to the set value calculated by the control means. It turned out to be within acceptable values. Therefore, when the room temperature is 22 ° C., the temperature of the coolant is also set to 22 ° C., the cylinder bore diameter is 80 mmφ, and the cylinder interval is 105 mm.
The inner surface of the four-cylinder cylinder block was subjected to internal quenching to form six rows of checkered partial quenched layers. In order to make the gap between the induction heating coil 23 and the inner diameter of the cylinder 1.25 mm, a diameter 77.5 in which 12 concave portions 74 are formed at equal intervals in the circumferential direction of the inner peripheral wall of the cylindrical dielectric member 71 shown in FIG.
A heating coil with a 70 mm inductor 70 was used. Using this induction coil, the drive unit 25 is operated by the control means 100 to set the induction heating coil 23 to the position of the first quenching row in the vertical direction of the inner diameter of the cylinder, and to heat it by heating. On the inner peripheral wall 76 of the cylinder 75 facing each concave portion 74 of the derivative member 71, a first partly quenched layer of twelve checkered patterns 76a as shown in FIG. 9 was formed. When the quenching of the first row is completed, the induction heating coil 23 is set to the position of the quenching row of the second row in the cylinder, and the rotation angle of 1/24 circle is rotated to obtain the second quenching as shown in FIG. A row of checkered partially quenched layers were formed. The same operation was repeated to form six rows of partially divided quenched layers.

FIG. 7 shows the measurement results of the variation in the size of the quenched portion. The figure shows the measured values of the lengths of the individual quenched portions around the circumference of the five cylinder blocks that were quenched every 5 minutes after the quenching operation was started 5 minutes after the start of operation of the apparatus. As can be seen from the figures, the difference in the length of the quenched portion around the circumference of each cylinder block was 1.5 mm or less. Illustration was omitted because only a slight difference was recognized in the width of the quenched portion. In addition, as a result of inspecting the quenched portion by fluorescent flaw detection, no quenching crack was observed in any of the quenched portions. That is, 3 which is used for ordinary quenching heat treatment
It was found that according to the present quenching method, even if a cooling liquid having a temperature of 0 ° C. or less was used, there was no quenching crack and a sound quenched layer was obtained.

As described above, according to the quenching method of the present invention,
Since the quenching and cooling is performed using a room temperature coolant, the temperature change of the device is small from the start to the end of the work, so the fluctuation of the interval between the position measuring means and the induction heating coil is reduced, and the measured value at the start of the work Precise quenching is possible even if quenching work is performed without correction using the numerical values set by the control means. In addition, it was confirmed that if the liquid temperature was 20 ° C. or more, even if rapid cooling was performed with a cooling liquid at room temperature, burning cracks did not occur. Therefore, costly equipment such as a special chiller for cooling liquid is not required.
Precise induction quenching can be performed without the need for complicated control means.

[0036]

As described above, according to the precision induction quenching method of the present invention, precise induction quenching can be easily performed by hardening the inner surface of the cylinder block without adding any special equipment.

[Brief description of the drawings]

FIG. 1 is a coolant system diagram of a precision induction quenching apparatus according to an embodiment of the present invention.

FIG. 2 is a front view of the precision induction hardening device according to the embodiment of the present invention.

FIG. 3 is a side view of the precision induction hardening device according to the embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a control unit according to the embodiment of the present invention.

FIG. 5 is a detailed sectional view of a cooling liquid tank of the precision induction quenching apparatus according to the embodiment of the present invention.

FIG. 6 is a diagram showing a change in the distance between the position measuring means and the induction heating coil according to the embodiment of the present invention.

FIG. 7 is a diagram showing a variation in dimensions of a quenched portion according to the embodiment of the present invention.

FIG. 8 is a view showing an induction heating coil according to an embodiment of the present invention.

FIG. 9 is a view showing a shape of a quenched portion according to the embodiment of the present invention.

[Explanation of symbols] 11 Base frame 12 rails 21 Gate type frame 21b rail 22 Movable frame 23 Induction heating coil 24 vertical axis 25 Drive 26 Rotary drive 31 Support frame 32 Marpos measuring instrument 33 axes 34 Drive 40 XY table 41 X table 42 rails 43 Y table 44 pulse motor 45 Ball screw 46 Drive 48 Cooling liquid tank 49 Bottom plate 49a cavity 49b spout 51 Reference ring 70 inductor 71 Cylindrical derivative member 74 recess 75 cylinder 76 Cylinder inner surface 76a checkered quenched layer 81 pipe 82 Discharge valve 83 flow pipe 85 frame tank 86 pipe 87 Liquid receiving tank 88 pipe 89 pump 90 pipe 91 Liquid storage tank 92 pipe 93 pump 94 pipe 95 heat exchanger 96 pipes 100 control means 101 control unit 102 storage unit 104 Operation switch 105 Start switch M Master block W work block

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-37117 (JP, A) JP-A-9-3531 (JP, A) JP-A-9-67616 (JP, A) 18607 (JP, Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) C21D 1/02-1/84 C21D 9/00-9/44 C21D 9/50

Claims (2)

(57) [Claims] 1. Cylinder block immersed in liquid and held
A cooling liquid tank to be mounted and the cooling liquid tank
A movable XY table and the cylinder block
Position measuring means for measuring the center position of the cylinder bore of the rack
And an induction heating coil for induction heating the inner surface of the cylinder, and
According to the measured value of the position measuring means,
Center the cylinder bore with the center of the induction heating coil
Control means for driving the XY table so that
In the internal hardening device for the cylinder block equipped with
The quenched part of the insert is immersed in the cooling liquid in the cooling liquid tank, and
Through the induction heating coil with the quenched part of
After heating the part to be quenched to the quenching temperature,
Induction quenching by quenching and quenching by cutting off the current
When quenching, cool with room temperature cooling liquid
Precision induction hardening of cylinder block characterized by the following:
Law. 2. A cylinder block is immersed in a liquid and held.
A cooling liquid tank to be mounted and the cooling liquid tank
A movable XY table and the cylinder block
Position measuring means for measuring the center position of the cylinder bore of the rack
And an induction heating coil for induction heating the inner surface of the cylinder, and
According to the measured value of the position measuring means,
Center the cylinder bore with the center of the induction heating coil
Control means for driving the XY table so that
In the internal hardening device for the cylinder block equipped with
The quenched part of the insert is immersed in the cooling liquid in the cooling liquid tank, and
Through the induction heating coil with the quenched part of
After heating the part to be quenched to the quenching temperature,
Induction quenching by quenching and quenching by cutting off the current
When quenching, cool with room temperature cooling liquid
The temperature of the coolant supplied to the coolant tank is maintained at room temperature as described above.
Characterized by comprising a liquid temperature control means for holding
Precise induction hardening equipment for blocks.