JPH109342A - Imbalance correction device for crankshaft - Google Patents

Abstract

(57) Abstract: The present invention relates to a crankshaft unbalance correction device, and more particularly to an unbalance correction device capable of correcting an imbalance without reducing productivity even when the imbalance becomes excessive. The purpose is to provide. SOLUTION: A center hole position indicating device 14 includes a step 54.
By performing statistical processing on the results of measuring the unbalance of the crankshafts in steps 58 and 58, the center hole position is calculated such that the initial unbalance is included in the correctable range,
This center hole position is instructed to the center hole processing apparatus 10. By automatically correcting the center hole position in this manner, it is possible to maintain a state in which imbalance correction is possible without stopping the manufacturing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for correcting imbalance of a rotating body, and more particularly to an apparatus for correcting imbalance of a crankshaft.

[0002]

2. Description of the Related Art A crankshaft is provided with a balance weight for compensating for an unbalance of an inertia moment around a center hole center (hereinafter, simply referred to as an unbalance). However, the imbalance of the crankshaft cannot be completely eliminated only by providing the balance weight due to a processing error or the like when processing the crankshaft. For this reason, in the crankshaft manufacturing process, after the final shape of the crankshaft is formed, the final imbalance is corrected. For example, in a method of manufacturing a crankshaft disclosed in Japanese Patent Application Laid-Open No. 1-257528, first, center holes are formed at both ends of a cast crankshaft coarse material, and a journal, a crankpin, and the like are formed based on the center holes. Are processed by cutting or grinding. And after the crankshaft is processed to the final shape,
The imbalance is corrected based on the center hole.

[0003]

Generally, correction of imbalance in the crankshaft manufacturing process is performed by changing the weight distribution of the balance weight by drilling holes in the balance weight.
Therefore, the imbalance that can be corrected by such a drilling is limited by the shape of the balance weight and the like. Since a crankshaft is often manufactured using a cast material as a rough material, a large error is likely to occur in the dimension of each cast rod. For this reason, the unbalance amount of the crankshaft may increase beyond the range that can be corrected by drilling holes in the balance weight.

In the conventional method for manufacturing a crankshaft, such imbalance correction is performed immediately before final finishing of the crankshaft, and no measures are taken when the imbalance exceeds a correctable range. Not. Therefore, in such a case, it is necessary to correct the crankshaft coarse material and correct the casting mold.
The manufacturing process will be stopped for a long time.
As described above, the unbalance correction in the conventional method for manufacturing a crankshaft cannot cope with a case where the unbalance amount exceeds a correctable range, and in such a case, the productivity is significantly reduced. It had the following.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and is intended to correct an unbalance without reducing productivity even when a large unbalance occurs due to a dimensional error of a coarse material. It is an object of the present invention to provide a crankshaft imbalance correcting device capable of performing the following.

[0006]

The object of the present invention is to provide an imbalance detecting means for detecting an imbalance of a crankshaft with reference to a center hole, and to detect the imbalance based on the imbalance detected by the imbalance detecting means. An apparatus for correcting imbalance of a crankshaft, wherein the target position of the center hole is calculated based on the unbalance detected by the unbalance detecting means, and the target position is determined by the center hole. This is achieved by a crankshaft imbalance correcting device provided with a center hole position indicating means for instructing a processing machine for processing a hole.

In the present invention, the unbalance detecting means detects the unbalance of the crankshaft based on the center hole. The center hole position indicating means calculates a target position of the center hole based on the unbalance detected by the unbalance detecting means, and instructs the target position to a processing machine for processing the center hole. Therefore, the position of the center hole is corrected based on the unbalance of the crankshaft with respect to the center hole. Thereby, the unbalance after the position of the center hole is corrected is changed based on the unbalance before the correction.

[0008]

FIG. 1 is a diagram showing a crankshaft manufacturing system according to one embodiment of the present invention. As shown in FIG. 1, the present system includes a center hole processing device 10, a crankshaft processing device 12, and a center hole position indicating device 14. FIG. 1 also shows crankshaft manufacturing processes 52 to 62 performed in the crankshaft processing apparatus 12. Center hole processing device 10
Is a numerically controlled machining machine capable of machining a hole to a target position commanded from the outside, and performs machining of a center hole in a crankshaft coarse material formed by casting. In addition, the crankshaft processing device 12 has a function of performing crankshaft machining and balance measurement, and performs a series of machining processes on the crankshaft coarse material having the center hole processed, Finish the crankshaft to the final product. Further, the center hole position indicating device 14 calculates a center hole target position based on the crankshaft balance measurement result, and transmits the target position to the center hole processing device 12 as a position command.

FIG. 2 is a view showing an example of a crankshaft manufactured by the system shown in FIG. The crankshaft 20 shown in FIG. 2 is used for a V-type 6-cylinder engine for a vehicle, and includes a journal portion 20a,
20b, 20c, 20d, crank pins 22a, 22
b, 22c, 22d, 20e, and 20f. Also, the crank pins 22a, 22b, 22c, 22d, 2
0e, 20f, and the balance weights 24a, 24b,
24c, 24d, 24e and 24f are provided. The balance weights 24a to 24f are connected to the pins 22a to 22f.
This is provided to compensate for the imbalance of the crankshaft 20 caused by the above. The journal unit 20
Unless otherwise specifically distinguished between a to 20d, crank pins 22a to 22f, and balance weights 24a to 24f, they are simply referred to as a journal 20, a crank pin 22, and a balance weight 24, respectively.

At both ends of the crankshaft 20, a front shaft 26 and a rear flange 28 are provided, respectively. A screw hole 30 and a pilot hole 32 are formed in the center of the front shaft 26 and the rear flange 28, respectively. These screw holes 30 and pilot holes 32
Are formed in a tapered shape, and the center holes 34 and 36, which serve as references when the steps 52 to 62, which will be described later, and when the crankshaft 20 operates, respectively.
Used as

The crankshaft 20 is made of carbon steel for machine structural use. A crankshaft coarse material formed by casting into a shape close to a substantially final shape, that is, a shape including the above-mentioned journal portion 20, crankpin 22, balance weight 24, front shaft 26, and rear flange 28, is described below. , The final product of the crankshaft 20 is manufactured.

As shown in FIG. 1, first, a crankshaft coarse material is introduced into a center hole machining apparatus 10. In the center hole drilling device 10, the journals 20a,
In a state where 0d is fixed, center holes 34 and 36 are formed by machining on the end surfaces of the front shaft 26 and the rear flange 28 with reference to the outer peripheral surfaces of the journals 20a and 20d, respectively.

The crankshaft coarse material that has been processed by the center hole processing device 10 is then introduced into a crankshaft processing device 12, where a series of mechanical processing to the final shape is performed. In the crankshaft processing device 12, first, in step 52, the outer peripheral surface of each part is cut. This cutting is performed for the purpose of removing black scales from each part.

When the processing in step 52 is completed, then, in step 54, the unbalance of the crankshaft 20 is measured. The measurement of the unbalance in the step 54 is performed by rotating the processing work around the center hole in a state where a plurality of load sensors are arranged via rollers at a plurality of positions around the crankshaft 20 and the output of each load sensor is measured. This is done by detecting differences. Since the unbalance measurement method is a known method, a detailed description thereof will be omitted. The unbalance measurement data obtained in step 54 is transmitted to the center hole position indicating device 14.

When the process of step 54 is completed, next, in step 56, the outer peripheral surface of each part of the crankshaft 20 is ground. By the processing in the step 56, each part of the crankshaft 20 is formed to a substantially final shape and dimensions. When the processing in step 56 is completed, next, in step 58, the unbalance of the crankshaft 20 is measured. The unbalance measurement in step 58 is performed in the same manner as in step 54 described above, and this measurement data is also transmitted to the center hole position indicating device 14.

When the process of step 58 is completed, next, in step 60, imbalance correction is performed. The details of the imbalance correction will be described later. When the imbalance correction in the step 60 is completed, the surface is finished by paper wrap in the step 60, and the manufacture of the crankshaft 20 is completed.

Next, the imbalance correction in step 60 will be described. The imbalance is caused by the displacement of the center of gravity with respect to an axis connecting the center of the center hole (hereinafter, simply referred to as the center hole center), and the unbalance corresponds to the displacement of the center of gravity with respect to the center of the center hole. Therefore, the imbalance can be corrected by moving the position of the center of gravity toward the center hole center. Therefore,
In step 60, the weight distribution of the balance weight 24 is adjusted by forming a correction hole in the balance weight 24, and the imbalance correction is performed by changing the position of the center of gravity of the crankshaft 20. FIG.
7 shows a state in which the correction holes 38 and 40 are formed in the balance weight 24 to correct the imbalance. Note that FIG.
Are arranged so that both axes intersect at right angles at the center hole center O of the crankshaft 20, and the Z axis coincides with the symmetry axis of the balance weight 24.

As shown in FIG. 3, the correction holes 38 and 40 form an angle θ with respect to the Z axis of the balance weight 24, and
The center line is provided so as to pass through the center hole center O.
When the correction holes 38 and 40 are provided deeply, the weight at the correction hole formation site is reduced. The degree of this decrease increases as the depth of the center holes 38 and 40 increases. Therefore, by providing the correction holes 38 and 40, the center of gravity G of the crankshaft 20 moves in the center axis direction of the correction holes 38 and 40 by a distance corresponding to the depth of the correction holes 38 and 40. In this case, the center of gravity G can be moved in the Z direction by adjusting the sum of the depths of the correction holes 38, 40, and the center of gravity can be moved by adjusting the difference between the depths of the correction holes 38, 40. G can be moved in the Y direction. Therefore, when correcting the imbalance, the sum of the depths of the correction holes 38 and 40 is obtained from the Z component of the unbalance, and the difference between the depths of the correction holes 38 and 40 is obtained from the Y component of the unbalance. From the sum and difference, each correction hole 3
By determining the depth of 6, 38, the imbalance can be corrected towards zero.

The above-described processing of the correction holes 38 and 40 is performed in the crankshaft processing apparatus 12 by the balance weight 24.
The drilling is performed on the outer peripheral portion of the device. As described above, when correcting the imbalance, the correction holes 38,
It is not necessary to change the position of 40, it is only necessary to control its depth. Therefore, it is not necessary to control the position of the tool for processing the correction holes 38 and 40, and thereby,
The imbalance correction process has been simplified.

However, the positions of the correction holes 38 and 40 are
The depth of the correction holes 38 and 40 is predetermined.
Since the size of the weight 24 is limited, the correction hole 3
The range of unbalance that can be corrected by 8, 40 is limited
It is. As described above, each of the correction holes 38 and 40 is machined.
The direction of movement of the center of gravity G is the direction of the center axis of each correction hole.
And the amount of movement of the center of gravity G depends on the depth of each correction hole.
Defined by Therefore, the vector indicating the movement of the center of gravity G
Are oriented in the direction of the central axis of the correction holes 38 and 40, and each correction hole
Is the sum of vectors having a magnitude corresponding to the depth of Figure
4 by controlling the depth of the correction holes 38 and 40.
This shows the range of imbalance that can be corrected. As shown in FIG.
The range of the imbalance that can be corrected depends on the correction holes 38 and 40.
Facing the central axis, depending on the maximum depth of the correction holes 38, 40
Vector v with different magnitude₁, V _TwoGenerated by
A diamond-shaped region H is obtained. Note that FIG.
An example of the lance measurement result is indicated by an x mark.

As described above, since the range of the imbalance that can be corrected is limited to the region H shown in FIG. 4, when designing the machining dimensions of each step of the crankshaft coarse material and the crankshaft 20, the step 58 Immediately before the imbalance correction, that is, immediately after the completion of the grinding in the step 56, it is designed such that the imbalance included in the region H occurs. The imbalance immediately before the imbalance correction, which is intentionally provided in the design as described above, is hereinafter referred to as an initial imbalance.

However, when casting the coarse material of the crankshaft 20, a large dimensional error is apt to occur due to variations in mold accuracy and the like, and the initial imbalance deviates from the region H due to the dimensional error of the coarse material. Sometimes. Under such circumstances, it becomes impossible to remove the imbalance of the crankshaft 20 by machining the correction holes 38 and 40. In this case, if measures were taken to correct the dimensions of the crankshaft coarse material as a measure for putting the initial imbalance in the region H, the correction processing of the crankshaft coarse material and further the correction processing of the mold were performed. Because of this, the manufacturing process is stopped for a long time, and the productivity is greatly reduced.

On the other hand, the system according to the present embodiment corrects the position H of the center holes 34 and 36 based on the result of the unbalance measurement, thereby correcting the region H in which the unbalance can be corrected, thereby improving productivity. It is characterized in that imbalance correction can be performed without lowering.

As described above, the variation in the shape of the cast material, which is a coarse material of the crankshaft 20, is determined by the dimensional accuracy of the mold, and therefore shows the same tendency for each cast rod. Therefore, the initial imbalance of the crankshaft 20 processed from the crankshaft coarse material having the same rod shows a similar tendency. The measurement data indicated by x in FIG. 4 is for a crankshaft 20 machined from a crankshaft coarse material of the same rod. As shown in FIG. 4, the initial imbalance for the same rod is concentrated in the range S. In FIG. 4, a part of this distribution is out of the region H, and the imbalance out of the region H cannot be corrected by the correction holes 38 and 40.

As described above, since the unbalance of the crankshaft 20 is caused by the displacement of the center of gravity G of the crankshaft 20 with respect to the center hole center O, the unbalance is obtained by changing the center hole position O. Can be adjusted. That is, if it can be detected early that the unbalance shows a certain tendency (in the case of FIG. 4, it is biased to the lower left direction), the center hole position is corrected in accordance with this tendency, so that the crank to be processed thereafter can be detected. This allows the initial imbalance of the shaft 20 to be entirely within the region H. FIG. 5 shows a state in which the correctable region H has moved by moving the center hole center O of the crankshaft 20. In FIG.
By moving the center hole center O to the lower left, the region H indicating the range of the imbalance that can be corrected moves to the region H ′, whereby all the measurement data shown in FIG. 4 is included in the region H ′. ing.

Therefore, in the present embodiment, the center hole position is corrected by the center hole position indicating device 14 based on the unbalance measurement data in the steps 54 and 58 as described above. That is, the center hole position determination device 14 estimates the tendency of unbalance by statistically processing the unbalance measurement data, and determines the correction position of the center hole based on the estimated value. And
By giving such a target position to the center hole processing apparatus 10 as a position command, the center hole 34 and the center hole 36 are provided.
Are processed to the corrected positions.

As described above, the initial imbalance of the crankshaft 20 processed from the same rod material of the crankshaft shows a similar tendency. For this reason, if the initial unbalance of the initially processed crankshaft 20 in a certain rod shows a certain tendency, the initial imbalance of the crankshaft 20 following this rod also shows the same tendency. is expected. Therefore, by correcting the positions of the center holes 34 and 36 based on all the unbalance measurement data obtained for past work pieces in the same rod, the initial unbalance of the work in the rod is corrected. It can be located within the possible range.

Statistical processing in the center hole position supporting device 14 includes, for example, an average value of past unbalance measurement data,
Calculate statistics such as a median and a standard deviation indicating the tendency of the data population, and calculate the center holes 34, 3
6 is corrected toward the center of gravity G. By correcting the center hole position based on the statistical data in this way, it is possible to prevent the center hole position from being unnecessarily changed by specific data.

By the way, since the number of machining steps required to reach the step 58 is large, the crankshaft 20 to be machined first in the rod (when the crankshaft 20 being machined is referred to individually, That)
Has reached the step 58, a considerable number of processed workpieces have already entered the processing step after the center hole processing. Further, as described above, the correction of the center hole position is performed by performing statistical processing on a plurality of data, so that a larger number of processed workpieces enter the processing process before the correction of the center hole position is performed. . Therefore, when the above-described statistical processing is performed by the center hole position determination device 64 based on only the balance measurement result in the step 58, the center hole position is not corrected for these processed workpieces, and thus the unbalance correction is performed. There is a possibility that a work that cannot be performed may occur. Therefore, in this embodiment, step 58
In addition, the balance measurement is also performed in the process 54 located relatively upstream, and such measurement data is taken into consideration when correcting the center hole position.

Since the measurement of the unbalance in the step 54 is located upstream of the step 58 by the grinding step of the step 56, the measurement result does not always correspond to the initial unbalance measured in the step 58. However, as described above, the fluctuation of the initial imbalance is mainly caused by the variation in the dimensions of the coarse material,
The imbalance measurement at step 54, located relatively upstream, can be considered to be a significant reflection of the initial imbalance measured at step 58. Therefore, by correcting the center hole position also by using the unbalance measurement result in the step 54, the unbalance correction can be performed earlier, thereby causing the generation of a work piece that cannot be corrected. Can be minimized.

In this case, in the statistical processing in the center hole position indicating device 14, the measured data in the step 54 and the
The measurement data in step 8 may be treated equally and statistically processed, or the measurement data in each step may be weighted and then statistically processed.

As described above, according to the system of the present embodiment, even if the dimensional error of the crankshaft coarse material becomes excessive, the initial imbalance is corrected without correcting the crankshaft coarse material or the mold. It can be in the possible range. Further, the correction of the center hole center is automatically performed when a position command is given from the center hole position indicating device 14 to the center hole processing device 10, so that the manufacturing process is stopped to correct the center hole center. It is not necessary to do so. As described above, in this embodiment, the unbalance correction of the crankshaft that can maintain high productivity is realized.

It should be noted that even a coarse crankshaft cast with the same rod, due to wear of the mold during casting, etc.
Its dimensions may change gradually. In such a case, the initial imbalance amount also gradually changes within the same rod. Further, even when a processing error occurs in the process 52 or 56 due to wear of a tool in the crankshaft processing device 12, the initial imbalance of the crankshaft 20 gradually increases as the number of workpieces increases. Will change. On the other hand, in the system according to the present embodiment, the center hole position indicating device 14 corrects the center hole position by using all the past data of the same rod. Therefore, as described above, even when the initial imbalance gradually changes within the same rod, the center hole position is appropriately corrected based on the information including the measurement data of these gradually changing imbalances, so that the initial hole is appropriately corrected. The balance can always be in the region H that can be corrected.

As described above, the initial imbalance is
Each rod of coarse material has a unique tendency. Therefore, using the unbalance measurement data obtained for a certain rod work, the unbalance correction of the work of different rods is performed, or the statistical processing of the data is performed in a state where the measurement data of the work of different rods are mixed. Therefore, it is not possible to make an appropriate imbalance correction. In this case, for example, the center hole position indicating device 14 stores the identification code indicating the rod together with the measurement data, and manages the unbalanced measurement data for each rod, thereby performing processing in a state where workpieces of different rods are mixed. Also in this case, the center hole position can be appropriately corrected for each rod.

It should be noted that, in the above embodiment, the present invention
Although the present invention is applied to the correction of the unbalance of the crankshaft 20 for the type 6 cylinder engine, the present invention is not limited to this, and may be applied to the correction of the unbalance of the crankshaft of any other type. Further, the present invention can be applied not only to the crankshaft but also to the imbalance correction of any rotating body requiring the imbalance correction.

[0036]

As described above, according to the present invention, the unbalance of the crankshaft can be changed so as to be included in a range where the unbalance can be corrected. Thus, even when the dimensional error of the coarse material is large, the imbalance correction can be performed without reducing the productivity.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a crankshaft manufactured in the embodiment.

FIG. 3 is a diagram showing a state where a correction hole is machined in a balance weight.

FIG. 4 is a diagram showing a range of unbalance that can be corrected by machining a correction hole in a balance weight, together with an example of unbalance measurement data.

FIG. 5 is a diagram showing a state in which the range of unbalance that can be corrected by correcting the center hole has been changed.

[Explanation of symbols]

 Reference Signs List 10 center hole processing device 12 crankshaft processing device 14 center hole position indicating device 20 crankshaft 24 balance weight 34, 36 center hole 38, 40 correction hole

Claims (1)

[Claims] 1. An unbalance detecting means for detecting an unbalance of a crankshaft with reference to a center hole, and correcting the imbalance of the crankshaft based on the unbalance detected by the unbalance detecting means. An apparatus for correcting an unbalance of a crankshaft, wherein a target position of the center hole is calculated based on the unbalance detected by the unbalance detecting means, and the target position is converted to a processing machine for processing the center hole. An unbalance correcting device for a crankshaft, comprising a center hole position indicating means for indicating.