JP2012061490A - Method for correcting dimension of cast - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for correcting a dimension of a cast capable of correcting the dimension for a short period of time without relying on skills of an operator, and obtaining a stable dimension after correcting.SOLUTION: The method for correcting the dimension of the cast includes: measuring the dimension P being the depth to the center in the tire width direction on a tread pattern formation surface of a cast sector mold, and the dimension Q being the width on the tread pattern formation surface of the sector mold; obtaining the relation between the input and the variation of the dimension P, and the relation between the dimension P and the dimension Q by taking out the sector mold as a sample, giving an input, and measuring the variation of the dimension P; setting the size of the input given to the sector mold to be corrected based on the measured dimension P and the dimension Q, the relation between the input and the variation of the dimension P, and the relation between the dimension P and the dimension Q; and correcting the dimension by giving the set input to the sector mold to be corrected, and deforming the sector mold.

Description

  The present invention relates to a method for correcting a dimension of a casting after casting, and more particularly to a method for correcting the dimension by applying an external force to the casting.

As a method for producing a sector mold for a tire vulcanizing mold, a low-pressure casting method as shown in FIG. 8 is known. In the low-pressure casting method, a molten metal holding furnace 51 containing a molten metal 50 such as an aluminum alloy is sealed with a lid member 52, and a gypsum mold 53 serving as a lower mold is placed on the lid member 52. A platen 54 of a metal plate serving as an upper mold is installed on the top, and the molten metal 50 is sent from the molten metal holding furnace 51 into the cavity 53a formed in the gypsum mold 53 to be cooled, whereby the sector mold 10 as shown in FIG. Casting.
A runner 53b is drilled in the bottom surface of the plaster mold 53, and the runner 53b communicates with the cavity 53a. On the other hand, the lid member 52 is formed with a compressed air introduction hole 52a and a runner 52b communicating with the runner 53b of the gypsum mold 53, and one end of the runner 52b is the melt 50 of the molten metal holding furnace 51. The other end side of the molten metal introduction pipe 55 arranged inside is connected. As a result, if the compressed air is introduced into the molten metal holding furnace 51 from the compressed air introduction hole 52a, the molten metal 50 is pushed up in the molten metal introduction pipe 55, and the molten metal channel 53b of the gypsum mold 53 from the molten metal channel 52b of the lid member 52 And is filled into the cavity 53a.

By the way, the casting is warped or twisted due to casting conditions such as molten metal temperature and mold temperature, shape factors such as length and thickness, and environmental factors such as temperature and humidity. These warps and twists are not uniform and vary even when manufactured under the same conditions.
For example, as shown in FIG. 9, in the sector mold 10 cast by the low pressure casting method, the outer peripheral surface 10b warps in the direction opposite to the tread pattern forming surface 10a side. The magnitude of this warpage is represented by a warpage amount s which is the difference between the highest position and the lowest position of the outer peripheral surface 10b. The warpage amount s varies depending on the casting conditions and the shape of the casting, but is about 0.3 to 0.5 mm when naturally cooled.
Conventionally, as a method of reducing warpage or twisting, a method of predicting warpage or twisting in advance and giving shape changes to the mold to eliminate warping or twisting of the finished casting (for example, , Patent Document 1) and a method of applying an external force to the cast product after casting to deform it (for example, refer to Patent Document 2).

Japanese Patent Laid-Open No. 11-320025 JP 2008-62247 A

However, in the method of predicting warpage and twisting in advance, in order to predict warpage and twisting using past experience, data, analysis software, etc., in addition to the need for knowledge and analysis software, Even if there is data, if the shape of the casting is not simple, it is difficult to construct an appropriate analysis model, and there is a problem that the actual casting dimensions do not match the prediction.
On the other hand, in the method of correcting by applying external force to the casting, the experience and skills of the operator are greatly affected, so if the inexperienced worker performs it, it takes a lot of man-hours and the dimension after correction is not stable There was a point.

  The present invention has been made in view of the conventional problems, and can perform dimension correction in a short time regardless of the skill of an operator, and further, a dimension correction method for a casting in which the dimension after correction is stable. The purpose is to provide.

The invention according to claim 1 of the present application is a casting dimension correcting method for correcting a dimension of the casting by applying an input to the casting manufactured by casting and deforming the casting, and presetting a plurality of castings that are cast in advance. Step (a) of measuring the dimensions of the location made, taking out a casting as a sample from the plurality of castings, giving an input to the sample, measuring the dimension of the sample, measuring the size of the input and the The step (b) for obtaining the relationship with the dimensional change, the relationship between the obtained input size and the dimensional change, and the measured casting size, and the magnitude of the input given to the casting to be corrected. A step (c) for setting the thickness, and a step (d) for applying the set input to the casting to be corrected to deform the casting and correcting the size of the casting. .
Thereby, since the magnitude | size of the input given to the casting which should be corrected can be set appropriately, the dimension of a casting can be corrected reliably in a short time.
Moreover, since the magnitude | size of an input can be set, for example, a casting can be automatically corrected using machines, such as a press machine which compresses and deform | transforms by inserting a casting from the upper and lower sides. Therefore, the dimension after correction can be stabilized.
Note that the sample is not taken out from the cast after casting, but the casting to be used as a sample is determined in advance, for example, the fifth cast and the tenth cast are used as samples. May be.

The invention described in claim 2 is a casting dimension correcting method for correcting a dimension of the casting by applying an input to a casting manufactured by casting to modify the casting, and presetting a plurality of castings that are cast in advance. A step (A) of measuring dimensions P and Q in directions parallel to two different directions p and q, respectively, taking out a casting as a sample from the plurality of castings, and giving an input to the sample A step (B) of measuring the dimension P and the dimension Q of the sample, the relationship between the magnitude of the input and the amount of change in the dimension P, or the relationship between the magnitude of the input and the amount of change in the dimension Q; Step (C) for determining the relationship between the dimension P and the dimension Q, the relationship between the determined input magnitude and the change amount of the dimension P, or the relationship between the input magnitude and the change amount of the dimension Q, the dimension P And dimension Q And (D) setting the magnitude of input given to the casting to be corrected from the measured dimensions P and Q, and deforming the casting by giving the set input to the casting to be corrected. And (E) for correcting the dimensions of the casting.
When the dimension of the casting is extended in a certain direction, the direction orthogonal to this direction is reduced. Therefore, if the input size is set so that the dimensions P and Q in two different directions p and q are both within the standard value as in the invention described in claim 2, the dimensions of the casting after correction are set. This variation can be further reduced.

  The summary of the invention does not list all necessary features of the present invention, and a sub-combination of these feature groups can also be an invention.

It is a flowchart which shows the dimension correction method of the casting which concerns on this Embodiment. It is a figure which shows the relationship between the magnitude | size of the input given to a casting, and the variation | change_quantity of a dimension. It is a figure which shows the setting method of the input value given to a casting. It is a figure which shows an example of the dimension correction apparatus of a casting. It is a figure which shows an example of the dimension correction method of a casting. It is a figure which shows an example of the dimension after correction of the casting corrected using the dimension correction method of the casting of this invention, correction time, and the variation after correction. It is a figure which shows an example of the dimension after correction of the casting corrected using the conventional dimension correction method of casting, correction time, and the variation after correction. It is a figure which shows an example of the conventional casting method. It is a figure which shows the curvature state of casting.

  Hereinafter, the present invention will be described in detail through embodiments, but the following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

FIG. 1 is a flowchart showing a dimension correction method for a casting according to the present embodiment.
In this example, as shown in FIG. 2, a method for correcting the dimensions of the sector mold 10 of a tire vulcanization mold obtained by casting will be described.
First, the dimension of the sector mold 10 cast is measured (step S10).
In this example, dimensions P and Q in directions parallel to two different directions p and q of the sector mold 10 are measured. The direction p is a direction perpendicular to the tire axial direction and the tire circumferential direction, and the radial dimension P is a depth at the center 10 m in the tire width direction of the tread pattern forming surface 10a which is a recess of the sector mold 10. The direction q is a direction parallel to the tire axial direction, and the dimension Q is the width of the tread pattern forming surface 10a of the sector mold 10.
When the bending moment M is applied to the sector mold 10 in the direction in which the dimension P increases, the dimension Q decreases. Conversely, when the bending moment m is applied in the direction in which the dimension P decreases, the dimension Q increases. Specifically, the dimensions P and Q can be changed by clamping both ends of the sector mold 10 and applying an external force (input) to the central portion by a cylinder or the like.
Note that the measurements of the dimension P and the dimension Q of the sector mold 10 are performed for all of the cast sector molds 10.

After the dimension measurement, a sample is extracted (step S11), and external force (input) is gradually added to the extracted sample by a certain value, and the dimension P and the dimension Q are measured each time (step S12). And the graph (graph 1) which shows the relationship between an input value and the variation | change_quantity of the dimension P and the graph (graph 2) which shows the relationship between the dimension P and the dimension Q are produced (step S13).
Here, the extraction number of cast sector mold 10 N _0, the sector mold members 10 do not need modification, i.e., the number of sector mold 10 and the dimensions P and dimensions Q are both within the standard value n _0, the sample Assuming that the number of sector molds 10 to be m is m, the number N of sector molds 10 whose dimensions need to be corrected is N = N ₀ −n ₀ −m. In this example, the sample is extracted from the sector mold 10 that needs to be corrected. Specifically, as a standard for sample extraction, the sector mold 10 in which both the dimension P and the dimension Q are deviated from the standard value and the deviation amount is an average value among N pieces is used. It should be noted that another extraction method may be used, such as using an average sector mold 10 having N pieces of deviation from the standard value of the dimension P. Or you may determine the sector mold 10 used as a sample previously, such as the sector mold 10 cast 5th and the sector mold 10 cast 10th.
The amount of change of the dimension P is obtained by gradually adding external force acting on the sample by a certain value and acquiring data of the dimension P each time.
The diagram shown in the lower left of FIG. 2 is an example of the graph 1, where the horizontal axis represents the input magnitude (input value) and the vertical axis represents the change amount of the dimension P. When the input value, which is the magnitude of the external force, is small, the dimension P hardly changes, but as the input value increases, the change amount of the dimension P increases rapidly.
On the other hand, since the direction p and the direction q are orthogonal to each other, the dimension Q is reduced when the dimension P is expanded. Therefore, when the horizontal axis is the value of the dimension Q and the vertical axis is the value of the dimension P, the graph 2 is lowered to the right as shown in the lower right diagram of FIG.

Next, a method for determining input values for N sector molds 10 whose dimensions need to be corrected will be described.
First, the sector molds 10 to be corrected are numbered (step S14), and target values of the dimensions P and Q are determined in order from the first (n = 1) (step S15). The method of determining the target value is as follows.
The crosses on the graph 2 shown in FIG. 3A indicate initial values (P ₁ , Q ₁ ) that are the dimensions P and Q of the sector mold 10 to be corrected. In order to correct the dimension P ₁ and the dimension Q _{1 of the} sector mold 10 so as to fall within the standard value region R surrounded by the rectangular frame in the figure, a target value (the target value of the dimension P and the dimension Q ( P ₂ , Q ₂ ) is determined. The target value (P ₂ , Q ₂ ) may be anywhere as long as it is within the region R of the standard value of the straight line in the graph 2, but in this example, the straight line indicated by the white circle in FIG. It is set near the midpoint of the line segment. The standard value region R is centered at (P ₀ , Q ₀ ), where the design dimension as the target value is (P ₀ , Q ₀ ) and the allowable values are ± δP, ± δQ. Is a rectangle having a length of 2δQ and a vertical axis of 2δP.
Then, as shown in FIG. 3A, the required change amount ΔP = P of the dimension P ₁ from the difference between the initial value (P ₁ , Q ₁ ) and the target value (P ₂ , Q ₂ ) using the graph 2. after determining the ₂ -P _1, as shown in FIG. 3 (b), to determine the necessary input values F with reference to the graph 1 (step S16). In the graph 1, an input value F corresponding to the change amount ΔP is a necessary input value.

After the necessary input value F is determined, the dimension correction of the sector mold 10 is performed using the dimension correction apparatus 20 as shown in FIG. 4A (step S17).
The dimension correcting device 20 includes a base 21, left and right vertical frames 22 and 23 erected at both ends in the width direction of the base 21, and a horizontal frame 24 provided so as to bridge the vertical frames 22 and 23. And a cylinder device 25 installed on the horizontal frame 24. The main body 25a of the cylinder device 25 is fixed to the horizontal frame 24, and a pressing plate 26 is provided at the tip of the cylinder rod 25b. Here, if the base 21 side is the lower side and the horizontal frame 24 side is the upper side, the cylinder rod 25b expands and contracts in the vertical direction.
The sector mold 10 to be corrected is placed on a plate-like table 27 installed on the upper surface 21a of the base 21 so that the outer peripheral surface 10b is on the upper side and the tread pattern forming surface 10a is on the lower side.
Then, as shown in FIG. 4B, the cylinder device 25 is driven to extend the cylinder rod 25b, and the pressing plate 26 is pressed against the outer peripheral surface 10b of the sector mold 10, thereby deforming the sector mold 10 and measuring the dimensions. Make corrections.
The dimension correcting device 20 of this example is provided with two cylinder devices 25 so that the dimensions of the two sector molds 10 can be corrected simultaneously. These dimensions may be corrected one by one, or the cylinder device 25 may be increased to simultaneously correct the dimensions of three or more sector molds 10.

As shown in FIG. 5 (a), most of the sector mold 10 after casting warps the outer peripheral surface 10b in a direction opposite to the tread forming surface 10a side. When the sector mold 10 is compressed by 26, as shown in FIG. 5B, the bending moment M acts in the direction in which the dimension P increases, and the dimension Q decreases. Some of the sector molds 10 are warped in the opposite direction to FIG. 5A, but if the dimension correcting device 20 of this example is used, the dimensions can be corrected in the same manner as in FIG. 5A. .
When the dimension correcting device 20 is not used, as shown in FIG. 5C, both ends of the outer peripheral surface 10b of the sector mold 10 are clamped and external force (input) is applied to the center 10m in the tire width direction by a cylinder or the like. What is necessary is just to give F toward the downward direction (or upper direction) of the figure.
As a result, the dimensions P and Q of the sector mold 10 can be corrected from the initial values indicated by the x marks in FIG. 3A to the target values indicated by the white circles in FIG.

After the dimension correction, the dimensions P and Q of the sector mold 10 are measured again, and it is confirmed whether or not the dimensions P and Q are within the standard value (step S18).
When the dimensions P and Q are within the standard value, it is determined whether or not the correction of the sector mold 10 has been completed (N in number) (step S19). Completes the correction work. If the correction of the sector mold 10 is not completed, the sector mold 10 to be corrected next is numbered (step S20), and then the process returns to step S15 to continue the dimension correction.
If the dimensions P and Q are not within the standard values in step S18, the process returns to step S15 and the dimensions are corrected again.

  As described above, in the present embodiment, when the cast sector mold 10 is input to be deformed and the dimensions of the sector mold 10 are corrected, the tread pattern forming surface 10a of the sector mold 10 has a center 10m in the tire width direction. Measure the dimension P which is the depth up to and the dimension Q which is the width of the tread pattern forming surface 10a of the sector mold 10, and take out the sector mold 10 as a sample and give the input to measure the amount of change of the dimension P. The relationship between the input and the change amount of the dimension P and the relationship between the dimension P and the dimension Q are obtained, the relationship between the measured dimension P and the dimension Q, the relationship between the input and the change amount of the dimension P, and the dimension P and the dimension. From the relationship with Q, the magnitude of the input given to the sector mold 10 to be corrected is set, and the set input is given to the sector mold 10 to be corrected and changed. Since such dimensions modified by, can be appropriately set the magnitude of the input applied to the casting to be corrected. Therefore, the dimensions of the casting can be reliably corrected in a short time, and the casting can be deformed using a machine, so that the dimension after correction can be stabilized.

In the above-described embodiment, the casting whose size is to be corrected is the sector mold 10 of the tire vulcanization mold. However, the present invention is not limited to this, and the present invention is not limited to this. Applicable.
In the above example, the dimension P is a dimension perpendicular to the tire axial direction and the tire circumferential direction, and the dimension Q is a direction dimension parallel to the tire axial direction. However, the present invention is not limited to this. The dimensions may be in the direction parallel to each of the two directions.
In the above example, the measured dimensions P and Q, the graph 1 showing the relationship between the input value and the amount of change in the size P, and the graph 2 showing the relationship between the dimensions P and Q are used to correct the dimensions. Although the input value is determined, it is also possible to determine the input value from the graph 1 showing the relationship between the input value and the amount of change in the dimension P and the measured dimension P ₁ . Specifically, the input value F may be determined from the graph 1 with the difference ΔP = P ₁ −P ₀ between the dimension P ₁ and the design dimension P ₀ as the amount of change in the dimension P. However, when the input value F is determined only by the dimension P, the target value is not near the midpoint of the line segment cut out in the standard value region R of FIG. Therefore, it is preferable that the target value is determined using the graph 1 and the graph 2 as in this example because the accuracy of dimensional correction is increased.

Of the cast sector mold, the sector mold in which one or both of the dimension P and the dimension Q is out of the standard is dimensionally corrected by the dimension correcting method according to the present invention, and the variation in the dimension after correction and the time required for the correction are obtained. The examination results are shown in the table of FIG. The number of corrected sector molds is 19. For comparison, the table of FIG. 7 shows the result of size correction by a conventional size correction method. In the present invention, the sector mold is deformed using a machine such as a dimension correcting device. On the other hand, in the conventional example, the sector mold was deformed using a vise.
Comparing FIG. 6 and FIG. 7, in the correction method of the present invention, the dimensional variation after correction of the casting is almost the same as that of the conventional correction method, but the time required for correction can be reduced by about 46%. I understand. This is because the input value can be set in the correction method of the present invention, and automatic correction by a machine is possible. In addition, since the automatic correction is performed by the machine, the worker can perform another work during the correction work, so that a further man-hour reduction effect can be obtained.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the embodiment. It is apparent from the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  As described above, according to the present invention, the dimensions of the casting can be reliably corrected in a short time, so that the dimension after the correction can be stabilized and the number of man-hours can be greatly reduced.

10 sector mold, 10a tread pattern forming surface, 10b outer peripheral surface,
10m tread pattern formation surface center in the tire width direction,
20 dimension correction device, 21 base, 22, 23 vertical frame, 24 horizontal frame,
25 cylinder device, 25a body, 25b cylinder rod, 26 pressing plate.

Claims (2)

A method for correcting the size of a casting, wherein an input is applied to a casting manufactured by casting to deform the casting, and the dimension of the casting is corrected.
Measuring a dimension of a preset location of a plurality of cast castings (a);
Taking out a casting as a sample from the plurality of castings, applying an input to the sample, measuring the dimension of the sample, and obtaining a relationship between the magnitude of the input and a change in the dimension; ,
Setting the magnitude of the input to be given to the casting to be corrected from the relationship between the obtained magnitude of the input and the amount of change in the dimension and the measured dimension of the casting;
A method for correcting the size of a casting, comprising the step (d) of applying the set input to the casting to be corrected to deform the casting and correcting the size of the casting. A method for correcting the size of a casting, wherein an input is applied to a casting manufactured by casting to deform the casting, and the dimension of the casting is corrected.
A step (A) of measuring dimensions P and Q in a direction parallel to two different preset directions p and q of a plurality of cast products,
(B) taking out a casting as a sample from the plurality of castings, giving an input to the sample, and measuring the dimension P and the dimension Q of the sample;
A step (C) of obtaining a relationship between the magnitude of the input and the change amount of the dimension P, or a relationship between the magnitude of the input and the change amount of the dimension Q, and a relationship between the dimension P and the dimension Q;
The relationship between the obtained input magnitude and the change amount of the dimension P or the relation between the input magnitude and the change amount of the dimension Q, the relation between the dimension P and the dimension Q, and the measured dimensions P and Q A step (D) of setting a magnitude of input given to the casting to be corrected;
A method for correcting the size of a casting, comprising the step of (E) correcting the dimension of the casting by applying the set input to the casting to be corrected to deform the casting.

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