JP7643327B2 - How to decide - Google Patents

Description

This disclosure relates to a measurement method and a determination method for measuring the amount of deformation of a struck member caused by the striking force of a striking device.

Conventionally, a method using a sand core has been used to manufacture castings with internal cavities, such as cylinder heads (for example, Patent Document 1). Molten metal is poured into a mold in which the sand core is placed, and after the molten metal solidifies, the sand core is removed from the casting that is removed from the mold. One method for removing the sand core from a casting is to strike the casting with a hammer from a striking device to knock off the sand core.

JP 2006-192470 A

When mass-producing castings, first, impact conditions such as air pressure and impact time are determined using a specific impact device. Then, it is determined whether the determined impact conditions can be applied to another impact device used in production. This is because even when the same impact conditions are set, there are individual differences in impact force depending on the impact device. If it is determined that the conditions are applicable, production is performed under the determined impact conditions. Whether the determined impact conditions can be applied to another impact device is determined by evaluating the impact force. One method for evaluating impact force is a measurement method using a load cell. However, impact devices are placed in various environments, and the measurement environments are also diverse. Therefore, a technology that can quantitatively evaluate impact force in a simpler manner is required.

The present disclosure can be realized in the following forms.
According to one aspect of the present disclosure, there is provided a method for determining whether or not to perform an impact process using predetermined impact conditions, using a deformation amount measured using a measurement method that measures the deformation amount of a struck member due to the impact force of an impact device. The striking device is a device that strikes a casting with a hammer in order to remove a sand core from the casting in which the sand core has been cast, and the measuring method includes a first step of placing the struck member in the same position as the striking position of the casting, a second step of striking the struck member with the hammer, and a third step of determining the amount of deformation of the struck member in the striking direction when struck, and the judgment method includes a fourth step of performing the second step using the striking conditions in a specific striking device that was used to determine the striking conditions, and setting a reference value using the deformation amount determined in the third step, performing the second step using the striking conditions in an striking device different from the specific striking device, and if the deformation amount determined in the third step is equal to or less than the reference value, determining that the striking process will be performed using the striking conditions, and if the deformation amount determined in the third step is greater than the reference value, determining that the striking process will not be performed using the striking conditions.

(1) According to one aspect of the present disclosure, there is provided a measurement method for measuring an amount of deformation of a struck member caused by the striking force of a striking device. The striking device is a device that strikes a casting with a hammer in order to remove a sand core from the casting into which the sand core has been cast, and the measurement method includes a first step of placing the struck member at the same position as the striking position of the casting, a second step of striking the struck member with the hammer, and a third step of determining the amount of deformation of the struck member in the striking direction. According to this aspect, the greater the striking force of the striking device, the greater the amount of deformation of the struck member, so the striking force can be evaluated by determining the amount of deformation of the struck member. Thus, the striking force can be quantitatively evaluated in a simple manner.
(2) In the measuring method of the above aspect, the struck member may be removably attached to the evaluation jig. According to this aspect, by replacing the struck member, the deformation amount can be repeatedly obtained using the same evaluation jig.
(3) In the measurement method of the above embodiment, the struck member may have a flat striking surface that is struck and a flat back surface opposite to the striking surface, and the amount of deformation may be found by subtracting a second thickness that is the distance between the striking surface and the back surface after striking from a first thickness that is the distance between the striking surface and the back surface before striking. According to this embodiment, the amount of deformation can be found by subtracting the second thickness from the first thickness. As the struck member has a flat striking surface and back surface, the amount of deformation can be found with high accuracy.
(4) According to another aspect of the present disclosure, there is provided a method for determining whether or not to perform a striking process using predetermined striking conditions by using the deformation amount measured by the measurement method of the above aspect. This determination method includes a fourth step of performing the second step using the striking conditions in the specific striking device used to determine the striking conditions, and setting a reference value using the deformation amount obtained in the third step, and performing the second step using the striking conditions in the striking device different from the specific striking device, and determining that the striking process is performed using the striking conditions if the deformation amount obtained in the third step is equal to or less than the reference value, and determining that the striking process is not performed using the striking conditions if the deformation amount obtained in the third step is greater than the reference value. According to this aspect, by using a change amount that allows for a simple evaluation of striking force, it is possible to easily determine whether or not to perform a striking process using predetermined striking conditions.
(5) In the determination method according to the above aspect, the striking conditions may include an air pressure that defines the striking force. According to this aspect, it is possible to determine whether or not to perform the striking process with respect to the striking conditions including the air pressure.
The present disclosure may be realized in various forms other than the measurement method or the determination method, for example, in the form of an evaluation jig to which a struck member is attached.

FIG. 2 is a schematic diagram showing the configuration of an impact device and an evaluation jig. 13 is a flowchart showing a deformation amount measuring process. FIG. 4 is a cross-sectional view of the struck member after being struck. FIG. 13 is a diagram showing the result of the deformation amount when the air pressure is changed. 1 is a flowchart showing a mass production process.

A. Embodiments:
Fig. 1 is a schematic diagram showing the configuration of an impact device 100 and an evaluation jig 200. As shown in Fig. 1, the impact device 100 includes a hammer 10, a compressed air supply device 20, an installation stand 30, a base plate 40, a plurality of air blow nozzles 50, a blow compressed air supply device 60, and a control device 80. The impact device 100 is a device for striking a casting into which a sand core (not shown) has been cast and which is installed on the installation stand 30, and for removing the sand core. Hereinafter, a casting into which a sand core has been cast may be simply referred to as a casting.

The hammer 10 has a hammer body 11 and a chisel 12. The chisel 12 has a cylindrical shape and is supported by the hammer body 11 so as to be movable in the axial direction. The impact device 100 is arranged in a position in which the axial direction of the chisel 12 is aligned with the vertical direction. A cylinder and a piston (not shown) are housed inside the hammer body 11. The piston is supported by the cylinder so as to be movable in the axial direction. The chisel 12 moves forward and backward in conjunction with the piston. The chisel 12 is biased in a direction away from the installation base 30 by a biasing member (not shown). The compressed air supply device 20 supplies compressed air into the cylinder. When compressed air is supplied from the compressed air supply device 20, the chisel 12 is pushed by the piston and advances in the impact direction, which is the direction toward the installation base 30 along the axial direction, against the biasing force of the biasing member. On the other hand, when the piston is not pushing the chisel 12, the biasing force of the biasing member causes the chisel 12 to retreat in the axial direction away from the installation base 30. The number and placement of the hammers 10 are set according to the shape of the casting. The number of hammers 10 is about two to four, and in this embodiment, there are two.

The casting is placed on a base plate 40 installed on a mounting table 30. The base plate 40 is formed to match the shape of the casting.

The air blow nozzle 50 is positioned so that its nozzle opening faces the casting. Compressed air is supplied to the air blow nozzle 50 from a blowing compressed air supply device 60. The air blow nozzle 50 ejects the supplied compressed air from its nozzle opening, blowing away the sand in the sand core that has been crushed by the impact of the hammer 10.

The control device 80 controls the compressed air supply device 20 and the blow compressed air supply device 60. Specifically, the control device 80 instructs the compressed air supply device 20 to a set air pressure. The compressed air supply device 20 supplies compressed air at the instructed air pressure to the hammer 10. The chisel 12 strikes the casting multiple times per second. The striking time during which the strikes are repeated is approximately 20 seconds or more and 60 seconds or less.

The impact force of the impact device 100 is determined by the air pressure of the compressed air supplied from the compressed air supply device 20. Specifically, the greater the air pressure, the greater the impact force. If the impact force is too high, cracks may occur in the casting. For this reason, in the impact process, the impact force is adjusted to a small level that does not cause cracks in the casting.

The mass production process for implementing the impact process for castings with new specifications at each factory will be described below. First, appropriate impact conditions are determined by experimentation for the castings with new specifications using a specific impact device 100. In addition to the air pressure and impact time described above, the impact conditions include the number of hammers 10, the position of the hammers 10 relative to the casting, and the shape of the base plate 40. Appropriate impact conditions are conditions under which the castings do not crack and the sand core can be removed within the target time.

Next, the impact force is measured for the impact device 100 at each factory that is used for mass production. Specifically, the impact force is measured when the air pressure is set to the evaluation pressure and the impact device 100 is struck. Note that the impact device 100 at each factory is a device that is different from the specific impact device 100.

Next, using the impact force measurement results, it is determined whether the impact conditions determined using a specific impact device 100 are applicable to the impact devices 100 at each factory. This is because even if the same impact conditions are used, differences in impact force and sand core removal force will occur depending on the manufacturer of the impact device 100 and individual differences in the device. One method for measuring impact force is to use a load cell that converts force into an electrical signal. When a load cell is used, if the measured impact force is within a preset range, it is determined that the impact conditions are applicable. If it is determined that the impact conditions are applicable, the impact process, which is part of the manufacturing process for castings with new specifications, is carried out under the impact conditions determined using a specific impact device 100.

When measuring using a load cell, it is necessary to adjust the measurement environment. Therefore, in order to evaluate the impact force using a simpler method, in this embodiment, the evaluation jig 200 is used to evaluate the impact force by determining the amount of deformation of the struck member 220 due to the impact. This makes it possible to determine in a simple manner whether the impact conditions are applicable. In addition, since load cells are expensive, the use of the evaluation jig 200 can suppress increases in manufacturing costs.

As shown in FIG. 1, the evaluation jig 200 has a size similar to that of a casting. The evaluation jig 200 has a jig body 210 and two struck members 220. In this embodiment, the evaluation jig 200 has a structure in which two plate-shaped members of different sizes are stacked in two stages with a gap in the thickness direction. The two struck members 220 are arranged at a position where the chisel 12 strikes when the evaluation jig 200 is installed on the installation table 30 via the base plate 40. In this embodiment, two struck members 220 are arranged, the same number as the number of hammers 10. The struck members 220 are made of aluminum. Since aluminum is easily deformed, it is possible to detect the striking force with high sensitivity. The struck members 220 are detachably attached to the jig body 210. Specifically, the struck members 220 have a cubic shape and have screw holes formed in the four corners. The struck member 220 is fixed to the jig body 210 by screwing the bolt inserted into the screw hole. This allows the striking force to be repeatedly evaluated using the same jig body 210 by replacing the struck member 220. The struck member 220 has a flat striking surface 220a that is struck and a flat back surface 220b on the opposite side to the striking surface 220a.

Figure 2 is a flow chart showing the deformation amount measurement process for realizing a measurement method for measuring the deformation amount of the struck member 220 due to the striking force of the striking device 100. Figure 3 is a cross-sectional view of the struck member 220 after it has been struck by the striking device 100. Figure 3 shows a cross-sectional view taken along a plane parallel to the thickness direction of the struck member 220, passing through an impact mark 221 formed by the striking surface 220a of the struck member 220 being recessed by the strike.

In step P10 shown in FIG. 2, striking conditions including air pressure are set in the striking device 100. In the first step P20, the struck member 220 is placed at the same position as the striking position of the casting. Specifically, the evaluation jig 200 is placed on the installation table 30 via the base plate 40 so that the struck member 220 is in a position to be struck by the chisel 12. In the second step P30, the struck member 220 is struck by the striking device 100.

In the third step P40, the deformation amount of the struck member 220 in the striking direction is obtained. Specifically, as shown in FIG. 3, the deformation amount d, which is the depth of the striking mark 221, is obtained by subtracting the second thickness t2, which is the thickness of the struck member 220 after striking, from the first thickness t1, which is the thickness of the struck member 220 before striking. The first thickness t1 is the distance in the thickness direction between the striking surface 220a and the back surface 220b before striking. The second thickness t2 is the distance in the thickness direction between the striking surface 220a and the back surface 220b after striking. The second thickness t2 is measured with a micro caliper. In this embodiment, the minimum value of the second thickness t2, that is, the maximum value of the deformation amount d, is adopted as the measured value. Note that the measured value adopted is not limited to the maximum value of the deformation amount d, and may be the average value of the measurement results measured at multiple locations. After the third step P40 is performed, this step ends.

Figure 4 is a diagram showing the results of the deformation amount d measured using the deformation amount measurement process according to this embodiment when the air pressure is changed. The first hammer and the second hammer shown in Figure 4 correspond to the two hammers 10 shown in Figure 1. Specifically, the air pressure was set to three values of 0.13 MPa, 0.21 MPa, and 0.26 MPa and measured. As shown in Figure 4, the deformation amount d increases as the air pressure that determines the impact force increases. In this way, since the deformation amount d and the magnitude of the impact force are correlated, it can be seen that the impact force can be evaluated using the deformation amount d.

Figure 5 is a flow chart showing the mass production process using the deformation measurement process. In process P100, a specific impact device 100 is used to experimentally determine appropriate impact conditions for a casting with new specifications.

In step P110, a deformation amount measurement step is carried out in a specific impact device 100 using the impact conditions determined in step P100. Specifically, the second step P30 (Figure 2) is carried out using the impact conditions. In the fourth step P120, a reference value is set using the deformation amount d determined in the third step P40 (Figure 2).

In process P130, the deformation amount measurement process is carried out using the impact conditions determined in process P100 on the target impact device 100, which is the impact device 100 of each factory used for mass production. Specifically, the second process P30 (Figure 2) is carried out using the impact conditions. Note that the impact device 100 of each factory is a device different from the specific impact device 100 used in process P100.

In process P140, it is determined whether the deformation amount d determined in the third process P40 is equal to or less than a reference value. If it is determined that the deformation amount d is equal to or less than the reference value, it is determined in process P150 that an impact process will be performed on the casting with new specifications under the impact conditions determined in process P100, and this process ends. By performing processes P140 and P150, a determination method is realized that determines whether or not to perform an impact process using predetermined impact conditions.

If it is determined that the deformation amount d is not equal to or less than the reference value, i.e., that the deformation amount d is greater than the reference value, then it is determined in process P160 that the impact process will not be performed using the impact conditions, and this process ends. If it is determined that the deformation amount d is greater than the reference value, the impact force will be large and the casting may crack. If it is determined in process P160 that the impact process will not be performed using the impact conditions, then the impact conditions are changed to match the target impact device 100 so that the appropriate impact conditions are obtained. Then, the impact process is performed using the changed impact conditions.

Although the above describes a case where the deformation amount measurement process is applied to a mass production process, the deformation amount measurement process can be used for purposes other than determining whether or not impact conditions are applicable in a mass production process. For example, the impact force of the impact device 100 may change due to deterioration. Therefore, the deformation amount d measured using the deformation amount measurement process according to this embodiment may be used to evaluate the change in impact force. Furthermore, when determining the air pressure and impact time in step P100 of the mass production process, the deformation amount d measured using the deformation amount measurement process according to this embodiment may be used to evaluate the change in impact force.

According to the embodiment described above, the deformation amount measurement process that realizes the measurement method for measuring the deformation amount d of the struck member 220 due to the striking force of the striking device 100 includes a first process P20 of placing the struck member 220 at the same position as the striking position of the casting, a second process P30 of striking the struck member 220 with the hammer 10, and a third process P40 of determining the deformation amount d of the struck member 220 in the striking direction. Since the deformation amount d increases as the striking force of the striking device 100 increases, the striking force can be evaluated by determining the deformation amount d of the struck member 220. Thus, the striking force can be quantitatively evaluated in a simple manner.

The struck member 220 is removably attached to the evaluation jig 200 for use. This allows the deformation amount d to be repeatedly determined using the same jig body 210 by replacing the struck member 220.

The struck member 220 has a flat striking surface 220a and a flat back surface 220b. The deformation amount d is calculated by subtracting the second thickness t2, which is the thicknesswise distance between the striking surface 220a and the back surface 220b after striking, from the first thickness t1, which is the thicknesswise distance between the striking surface 220a and the back surface 220b before striking. Therefore, the deformation amount d can be calculated by subtracting the second thickness t2 from the first thickness t1. Since the struck member 220 has a flat striking surface 220a and back surface 220b, the deformation amount d can be calculated with high accuracy.

In the mass production process, in process P110, the second process P30 is performed using the impact conditions on a specific impact device 100. In the fourth process P120, a reference value is set using the deformation amount d obtained in the third process P40. In process P130, the second process P30 is performed using the impact conditions on a target impact device 100 different from the specific impact device 100. If the deformation amount d obtained in the third process P40 is equal to or less than the reference value, it is determined in process P150 that the impact process is to be performed using the impact conditions determined in P100. In this way, the deformation amount d, which can easily evaluate the impact force, is used in the determination in process P140, so that it is easy to determine whether or not to perform the impact process using the impact conditions. In addition, the impact conditions include air pressure. This makes it possible to determine whether or not to perform the impact process for impact conditions including air pressure.

B. Other embodiments:
(B1) In the above embodiment, if the deformation amount d is equal to or less than a reference value in process P140, it is determined that the impact conditions are applicable. In process P140, not only an upper reference value but also a lower reference value may be set, and if the measured deformation amount d is equal to or less than the upper reference value or equal to or more than the lower reference value, it may be determined that the impact process is to be performed under the impact conditions in process P140. If the impact force is small, the sand core removal force may be small. For this reason, by setting a lower reference value, it is possible to appropriately remove the sand core in the impact process when it is determined that the impact process is to be performed under the impact conditions.

(B2) In the above embodiment, the struck member 220 is made of aluminum. The material of the struck member 220 is not limited to aluminum, and may be other easily deformable metal materials such as copper and nickel.

(B3) In the above embodiment, the mass production process is performed by workers, but it may also be performed by workers and equipment. Specifically, in the mass production process, the fourth process P120 and process P140 may be performed by a judgment device, which is, for example, an information processing device. This makes it possible to quickly determine whether or not to perform the impact process using the impact conditions.

The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features of the embodiments corresponding to the technical features in each form described in the Summary of the Invention column can be replaced or combined as appropriate to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

10...hammer, 11...hammer body, 12...chisel, 20...compressed air supply device, 30...installation stand, 40...base plate, 50...air blow nozzle, 60...blowing compressed air supply device, 80...control device, 100...impact device, 200...evaluation jig, 210...jig body, 220...struck member, 220a...struck surface, 220b...back surface, 221...impact mark, P20...first step, P30...second step, P40...third step, P120...fourth step, P10, P100, P110, P130-P160...steps, d...deformation amount, t1...first thickness, t2...second thickness

Claims (4)

A method for determining whether or not to perform a striking process using a predetermined striking condition, using a deformation amount measured using a measuring method for measuring a deformation amount of a struck member caused by a striking force of a striking device, comprising:
the striking device is a device for striking a casting with a hammer in order to remove a sand core from the casting into which the sand core has been cast,
The measurement method includes:
a first step of placing the struck member at the same position as a striking position of the casting;
a second step of striking the struck member with the hammer;
and a third step of determining the deformation amount of the struck member in the striking direction ,
The determination method includes:
a fourth step of performing the second step using the impact conditions in the specific impact device used to determine the impact conditions, and setting a reference value using the deformation amount obtained in the third step;
The method includes performing the second step using the impact conditions on an impact device that is different from the specific impact device, and if the deformation amount obtained in the third step is equal to or less than the reference value, determining that the impact step will be performed using the impact conditions, and if the deformation amount obtained in the third step is greater than the reference value, determining that the impact step will not be performed using the impact conditions. 2. The method of claim 1,
The method for determining whether or not the impacted member is a member that is detachably attached to an evaluation jig. The method according to claim 1 or 2,
The struck member has a flat striking surface that is struck and a flat back surface opposite to the striking surface,
A determination method in which the deformation amount is obtained by subtracting a second thickness, which is the distance between the striking surface and the back surface after striking, from a first thickness, which is the distance between the striking surface and the back surface before striking . 2. The method of claim 1 ,
The striking condition includes an air pressure that defines the striking force.

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