WO2020184480A1

WO2020184480A1 - Method for manufacturing formed material, and forming metal mold

Info

Publication number: WO2020184480A1
Application number: PCT/JP2020/009850
Authority: WO
Inventors: 修一岩永; 尚文中村
Original assignee: 日本製鉄株式会社
Priority date: 2019-03-14
Filing date: 2020-03-06
Publication date: 2020-09-17
Also published as: TWI813862B; JP7164009B2; CN113543903A; TW202039113A; JPWO2020184480A1

Abstract

Provided is a method for manufacturing a formed material, comprising manufacturing a formed material having a trunk portion and a flange portion by subjecting a raw-material metal plate to multi-stage drawing. The multi-stage drawing includes performing compressive drawing at least once for forming the trunk portion by drawing a trunk portion element while applying a compressive force to the trunk portion element using a metal mold which includes a die having a push-in hole, a punch, and a pressing means for applying a compressive force to the peripheral wall of the trunk portion element along a depth direction of the trunk portion element. The push-in hole has a tapered surface which extends in the circumferential direction of the push-in hole at the entry of the push-in hole, and which extends while being inclined with respect to the axial direction of the push-in hole. The push-in hole is configured such that component forces of the compressive force are directed toward radially inside of the push-in hole due to the tapered surface.

Description

Molding material manufacturing method and molding mold

The present invention relates to a molding material manufacturing method for manufacturing a molding material having a tubular body portion and a flange portion formed at an end portion of the body portion.

For example, as shown in Non-Patent Document 1 and the like below, a molding material having a tubular body portion and a flange portion formed at an end portion of the body portion is manufactured by performing drawing processing. Is being done. In the drawing process, the body portion is formed by stretching the material metal plate, so that the thickness of the peripheral wall of the body portion is usually thinner than the material plate thickness.

For example, as the motor case shown in Patent Document 1 and the like below, a molding material formed by drawing as described above may be used. In this case, the peripheral wall of the body is expected to have a performance as a shielding material to prevent magnetic leakage to the outside of the motor case. Further, depending on the structure of the motor, the performance of the stator as a back yoke is also expected from the peripheral wall.

The thicker the peripheral wall, the better the performance as a shield material or back yoke. For this reason, when manufacturing the molded material by drawing as described above, the thickness of the material metal plate is selected to be thicker than the target thickness of the peripheral wall of the body in anticipation of a decrease in the thickness of the body. Will be done. However, the plate thickness of the material metal plate is not always constant because it is affected by the manufacturing conditions and the like, and fluctuates within the allowable range of the plate thickness called the plate thickness tolerance. In addition, the amount of plate thickness reduction in drawing may fluctuate due to changes in the mold state, variations in material characteristics, and the like.

On the other hand, in recent years, the number of rotations of the rotor has been increased in order to improve the performance of the motor. A slight deviation between the rotor and the motor case causes vibration and noise. In order to reduce the vibration and noise of the motor, the inner diameter of the motor case may be required to have a highly accurate inner diameter roundness.

Therefore, normally, in the process after finishing the multi-stage drawing process, the body is finished and ironed to improve the roundness of the inner diameter. In this finishing ironing, the gap (clearance) between the die and the punch is set to be less than the material plate thickness of the body portion, and the material of the body portion is sandwiched from both the inner and outer sides by the die and the punch. Setting the clearance between the die and punch to be less than the material plate thickness of the body is called minus clearance.

According to Patent Document 2 and the like below, even if the thickness of the material metal plate fluctuates or the mold conditions fluctuate, the thickness of the peripheral wall of the body before finishing ironing is controlled to control the increase or decrease of the plate thickness. A molding material manufacturing method capable of maintaining the roundness of the inner diameter of the body with high accuracy by adjusting the thickness of the peripheral wall plate of the front body of the body is disclosed. In this molding material manufacturing method, finish ironing with a negative clearance, in other words, finish ironing to reduce the plate thickness of the body body, is performed to improve the accuracy of the roundness of the inner diameter.

Japanese Unexamined Patent Publication No. 2013-51765 Japanese Unexamined Patent Publication No. 2016-190245

In the above molding material manufacturing method, high-precision inner diameter roundness is obtained by finishing and ironing. However, when the accuracy of controlling the thickness of the peripheral wall plate of the body before finishing ironing is low, more specifically, when the peripheral wall of the body is excessively thickened, the following problems may occur.

That is, when the peripheral wall of the body is excessively thickened before finishing and ironing, the inflow of the body of the body into the gap between the die and the punch is hindered, and the body of the body or the peripheral wall of the body may be broken. ..
Further, when the material metal plate is a surface-treated steel plate having plating on its surface, the die and punch and the material may slide under high surface pressure, and plating slag may be generated. The plating slag can cause deterioration of the appearance of the molded material.
Further, galling may occur at the sliding portion between the die and the punch and the material, or the life of the mold may be shortened. There is a limit to the ironing ratio and the shoulder radius of the finishing ironing die, and the molding limit is set.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is a method for manufacturing a molding material and a molding material capable of improving the roundness of the inner diameter of a body portion without performing finish ironing. To provide a mold.

The molding material manufacturing method of the present invention is to manufacture a molding material having a tubular body portion and a flange portion formed at an end portion of the body portion by performing multi-stage drawing on a material metal plate. It is a molding material manufacturing method including, and in a multi-stage drawing, a preliminary drawing in which a spare body having a body body is formed from a material metal plate, a die having a push-in hole, and a die having a push-in hole are inserted inside the body body. After pre-squeezing using a mold that includes a punch that pushes the body into the push hole and a pressurizing means that applies a compressive force along the depth direction of the body to the peripheral wall of the body. It includes at least one compression squeeze, which forms the body by squeezing the body while applying compressive force to the body, and the push hole is a push hole at the entrance of the push hole. It has a tapered surface that extends in the circumferential direction of the indentation and is inclined with respect to the axial direction of the indentation hole so that the component of the compressive force is directed inward in the radial direction of the indentation hole. It is configured in.

The molding mold of the present invention is a molding mold for drawing a spare body having a body body, and is inserted into a die having a push-in hole and a body body. It is equipped with a punch that pushes the body into the push-in hole and a pressurizing means that applies a compressive force along the depth direction of the body to the peripheral wall of the body, while applying the compressive force to the body. It is configured to squeeze the body of the body, and the push-in hole extends in the circumferential direction of the push-in hole at the entrance of the push-in hole, and is tapered with respect to the axial direction of the push-in hole. It has a surface, and the tapered surface is configured so that the component force of the compressive force is directed inward in the radial direction of the push-in hole.

According to the molding material manufacturing method and the molding die of the present invention, the component force of the compressive force is directed inward in the radial direction of the push hole due to the tapered surface, so that the peripheral wall of the body body is pushed by the punch during the compression drawing. It can be attached, and the body body or the inner peripheral surface of the body can be formed on the outer peripheral surface of the punch without any gap. As a result, the roundness of the inner diameter of the body can be improved without finishing and ironing.

It is a perspective view which shows the molding material 1 manufactured by the molding material manufacturing method by Embodiment 1 of this invention. It is explanatory drawing which shows the molding material manufacturing method which manufactures the molding material of FIG. It is explanatory drawing which shows the mold used for the preliminary drawing of FIG. It is explanatory drawing which shows the preliminary drawing by the mold of FIG. It is explanatory drawing which shows the mold used for the 1st compression drawing of FIG. It is explanatory drawing which shows the 1st compression drawing by the die of FIG. It is a schematic diagram which showed the compressive force acting on the peripheral wall of the body body at the time of 1st to 3rd compression drawing. It is a graph which shows the relationship between the compressive force applied by the lifter pad at the time of the 1st to 3rd compression drawing, and the peripheral wall plate thickness distribution of the body part. It is explanatory drawing which shows the plate thickness measurement position of FIG. It is a graph which shows the relationship between the compressive force applied by the lifter pad 42 in the 1st to 3rd compression drawing steps, and the inner diameter of the body part after 3rd compression drawing. It is a graph which shows the relationship between the compressive force applied by the lifter pad in the 1st to 3rd compression drawing steps, and the roundness of the inner diameter of the body part after the 3rd compression drawing. The moldable range shown in Tables 2 to 6, the inclination angle θ of the tapered surface, and the compressive pressure P (the value obtained by dividing the compressive force in the depth direction received from the lifter pad by the cross-sectional area of the peripheral wall of the body). It is explanatory drawing which showed the relationship.

Hereinafter, a mode for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to each embodiment, and the components can be modified and embodied without departing from the gist thereof. In addition, various inventions can be formed by appropriately combining the plurality of components disclosed in each embodiment. For example, some components may be removed from all the components shown in the embodiments. Furthermore, the components of different embodiments may be combined as appropriate.

FIG. 1 is a perspective view showing a molding material 1 manufactured by the molding material manufacturing method according to the first embodiment of the present invention. As shown in FIG. 1, the molding material 1 manufactured by the molding material manufacturing method of the present embodiment has a body portion 10 and a flange portion 11. The body portion 10 is a tubular portion having a top wall 100 and a peripheral wall 101 extending from the outer edge of the top wall 100. The top wall 100 may be called another way such as a bottom wall depending on the orientation in which the molding material 1 is used. Although the body portion 10 is shown to have a perfect circular cross section in FIG. 1, the body portion 10 may have another shape such as an elliptical cross section or a square tubular shape. Further processing can be applied to the top wall 100, for example, by forming a protrusion further protruding from the top wall 100. The flange portion 11 is a plate portion formed at the end portion of the body portion 10 (the end portion of the peripheral wall 101).

Next, FIG. 2 is an explanatory diagram showing a molding material manufacturing method for manufacturing the molding material 1 of FIG. In the molding material manufacturing method of the present invention, the molding material 1 is manufactured by performing multi-stage drawing on the flat plate-shaped material metal plate 2. The multi-stage drawing includes a preliminary drawing and at least one compression drawing performed after the preliminary drawing. In the molding material manufacturing method of the present embodiment, compression (first to third compression) is performed three times. As the material metal plate 2, various steel plates can be used.

Preliminary drawing is a step of forming a spare body 20 having a body body 20a by processing the material metal plate 2. The body portion 20a is a tubular body having a diameter wider than that of the body portion 10 of FIG. 1 and a shallow depth. The depth direction of the body body 20a is defined by the extending direction (height direction) of the peripheral wall of the body body 20a. In the present embodiment, the entire spare body 20 constitutes the body body 20a. However, as the spare body 20, a body having a flange portion may be formed. In this case, the flange portion does not form the body body 20a.

As will be described in detail later, the first to third compression throttles apply a compressive force 42a (see FIG. 5) along the depth direction of the body body 20a to the body body 20a while applying the body body 20a. This is a step of forming the body portion 10 by squeezing. Squeezing the body body 20a means reducing the diameter of the body body 20a and increasing the depth of the body body 20a.

The spare body 20 after each compression drawing has a flange portion element body 20b that is inclined and extended with respect to the radial direction of the body portion element body 20a. The flange portion body 20b extends along the tapered surface 44 provided on the die 40 used for each compression drawing, as will be described in detail later. In the molding material manufacturing method of the present embodiment, the reserve body 20 is subjected to restoric processing after the third compression drawing. The wrist-like processing is a step of flattening the flange body 20b so that the flange body 20b extends along the radial direction of the body 20a or the body 10. Restorative processing can be performed by sandwiching the flange portion element body 20b between a die having no tapered surface 44, which will be described later, and a lifter pad arranged so as to face the die. In the wrist-like processing, the flange portion body 20b is processed while the peripheral wall diameter and height of the body portion 10 or the body portion body 20a are the same.

In the molding material manufacturing method of the present embodiment, the spare body 20 becomes the molding material 1 after undergoing the rest-like processing. However, for example, in a mode in which the flange portion 11 may be inclined and extended along the radial direction of the body portion 10, the restorike may be omitted and the molding material 1 may be obtained by the third compression drawing. Good.

Next, FIG. 3 is an explanatory view showing the mold 3 used for the preliminary drawing of FIG. 2, and FIG. 4 is an explanatory view showing the preliminary drawing by the mold 3 of FIG. As shown in FIG. 3, the die 3 used for the preliminary drawing includes a die 30, a punch 31, and a cushion pad 32. The die 30 is provided with a push-in hole 30a into which the material metal plate 2 is pushed together with the punch 31. The peripheral wall surface of the push-in hole 30a and the lower surface of the die 30 extend orthogonally to each other, and the peripheral wall surface of the push-in hole 30a and the lower surface of the die 30 are formed by a curved die shoulder portion having a predetermined radius of curvature. Can be connected. The die shoulder may be composed of a 90 degree arcuate surface. Further, the die shoulder portion defines the outer edge of the entrance of the push-in hole 30a. The cushion pad 32 is arranged at the outer peripheral position of the punch 31 so as to face the end surface of the die 30.

In the preliminary drawing of FIG. 4, the outer edge portion of the material metal plate 2 is not completely restrained by the die 30 and the cushion pad 32, and the outer edge portion of the material metal plate 2 is pulled out until it is released from the restraint of the die 30 and the cushion pad 32. .. All of the material metal plate 2 may be pushed into the push-in hole 30a together with the punch 31 and pulled out. When the spare body 20 having the flange portion is formed as described above, the drawing may be stopped at a depth at which the outer edge portion of the material metal plate 2 does not deviate from the restraint of the die 30 and the cushion pad 32.

Next, FIG. 5 is an explanatory view showing the mold 4 used for the first compression drawing of FIG. 2, and FIG. 6 is an explanatory view showing the first compression drawing of the mold 4 of FIG. As shown in FIG. 5, the die 4 used for the first compression drawing includes a die 40, a punch 41, and a lifter pad 42. The die 40 is a member having a push-in hole 40a. The punch 41 is a cylindrical body that is inserted into the body body 20a and pushes the body body 20a into the push-in hole 40a.

The push-in hole 40a has a tapered surface 44. The tapered surface 44 is a surface that extends in the circumferential direction of the push hole 40a at the entrance of the push hole 40a and is inclined with respect to the axial direction of the push hole 40a. The tapered surface 44 can be understood as the peripheral surface of a truncated cone whose bottom surface is arranged at the entrance of the push-in hole 40a. In the cross section in the direction orthogonal to the axial direction of the die 40, the tapered surface 44 constitutes a plane that is inclined and extended with respect to the axial direction of the die 40. The tapered surface 44 is provided so as to taper from the entrance of the push-in hole 40a toward the back. The inlet of the push-in hole 40a is the opening of the push-in hole 40a on the punch 41 side. As shown in FIG. 5, in the embodiment in which the punch 41 is arranged below the die 40, the inlet of the push hole 40a can be understood as the lower opening of the push hole 40a.

The inner diameter 40b of the inlet of the push-in hole 40a is set to be equal to or larger than the outer diameter of the peripheral wall of the body body 20a before compression drawing performed by using the die 40 having the push-in hole 40a. That is, in the mold 4 used for the first compression drawing shown in FIG. 5, the inlet inner diameter 40b of the push-in hole 40a is equal to or larger than the outer diameter of the peripheral wall of the body body 20a before the first compression drawing after the preliminary drawing. Has been done.

The difference between the inner diameter of the inlet 40b and the outer diameter of the peripheral wall of the body body 20a is preferably 3 times or more the plate thickness of the body body 20a. By taking such a dimensional difference, the body body 20a is molded without coming off the taper outside even when the center is misaligned due to transportation or the like. Therefore, it is possible to reduce the possibility that the peripheral wall of the body body 20a is sandwiched between the lower surface of the die 40 and the lifter pad 42 and buckled due to the applied compressive force. Further, in order to prevent the die 40 from becoming longer than necessary, the inlet inner diameter 40b of the push-in hole 40a is preferably equal to or less than the outer diameter of the flange portion body 20b required after each drawing process is completed.

The lifter pad 42 is arranged at the outer peripheral position of the punch 41 so as to face the die 40. Specifically, the lifter pad 42 has a pad portion 420 and an urging portion 421 (support portion). The pad portion 420 is an annular member arranged at an outer peripheral position of the punch 41 so as to face the die 40. The urging portion 421 is arranged below the pad portion 420, and urges and supports the pad portion 420. The urging portion 421 is configured so that the supporting force (urging force) that supports the pad portion 420 can be adjusted. The body body 20a is placed on the pad portion 420. More specifically, the lower end of the peripheral wall of the body body 20a is placed on the pad portion 420. The peripheral wall of the body 20a is sandwiched by the die 40 and the pad portion 420 when the die 40 is lowered. By sandwiching the peripheral wall of the body body 20a between the die 40 and the pad portion 420 in this way, the supporting force (compressive force by the lifter pad) of the urging portion 421 is along the depth direction of the body body 20a. It is applied to the body body 20a as a compressive force 42a. That is, the lifter pad 42 constitutes a pressurizing means for applying a compressive force 42a along the depth direction of the body body 20a to the body body 20a.

As shown in FIG. 6, in the first compression drawing, when the die 40 is lowered, the body body 20a is pushed into the push-in hole 40a together with the punch 41, and the body body 20a is squeezed. At this time, after the peripheral wall of the body body 20a is sandwiched by the die 40 and the pad portion 420, the compressive force 42a along the depth direction of the body body 20a continues to be applied to the body body 20a. That is, in the first compression drawing, the body body 20a is squeezed while applying a compressive force 42a. This first compression drawing is performed so that the pad portion 420 is completed before reaching the bottom dead center. The bottom dead center of the pad portion 420 means a position where the descent of the pad portion 420 is mechanically restricted, and is defined by the structure of the urging portion 421 or the position of a member that regulates the descent of the pad portion 420. .. In other words, the first compression drawing is performed so that the pad portion 420 does not bottom out. By performing the first compression throttle so that the pad portion 420 is completed before reaching the bottom dead center, the bearing capacity of the urging portion 421 is set as the compression force 42a during the first compression throttle. It acts on the body 20a. That is, in the first compression drawing, the body body 20a is squeezed while applying a compressive force 42a. Since the urging portion 421 is configured so that the bearing force can be adjusted as described above, the compressive force 42a is adjusted by adjusting this bearing force. When the compressive force 42a satisfies a predetermined condition, the body body 20a can be squeezed without causing the body body 20a to be thinned. By changing the compressive force 42a, the plate thickness of the body body 20a that has passed through the first compression drawing can be adjusted. Further, in the first compression drawing, the peripheral wall of the body body 20a is pressed against the tapered surface 44 and is pushed into the depth of the pressing hole 40a along the tapered surface 44.

During processing, the lower surface of the lifter pad 42 is in a state where it can move up and down freely in the vertical direction without contacting the upper surface of the punch holder 43. This is because the lifter pad 42 does not bottom out, and the lifter pad 42 that is about to rise due to the urging force (compressive force of the lifter pad) of the die 40 and the urging portion 421 that has descended during processing is the body element. It is in a state of being balanced through the body 20a.

The second and third compression draws of FIG. 2 are performed using a die having the same configuration as the die 4 shown in FIGS. 5 and 6. However, the dimensions such as the inclination angle θ of the die 40, the punch 41, and the tapered surface 44 are appropriately changed. In the second compression drawing, the body body 20a after the first compression drawing is squeezed while applying a compressive force 42a. Further, in the third compression drawing, the body body 20a after the second compression drawing is squeezed while applying a compressive force 42a. After passing through these first to third compression draws, the body body 20a is designated as the body 10. In the mold 4 used for the second compression drawing, the inlet diameter of the push-in hole 40a is set to be equal to or larger than the outer diameter of the peripheral wall of the body body 20a after the first compression drawing and before the second compression drawing. Similarly, in the mold 4 used for the third compression drawing, the inlet diameter of the push-in hole 40a is set to be equal to or larger than the outer diameter of the peripheral wall of the body body 20a before the third compression drawing after the second compression drawing. There is.

FIG. 7 is a schematic view showing the compressive force acting on the peripheral wall of the body body 20a during the first to third compression drawing. The compressive force 42a applied from the lifter pad 42 during the first to third compression drawing acts on the portion 46 before the diameter reduction in the depth direction of the body body 20a. On the other hand, at the portion where the peripheral wall of the body body 20a is pressed against the tapered surface 44, a compressive force 42b is generated along the tapered surface 44. The compressive force 42b has a component in a direction orthogonal to the axial direction of the push-in hole 40a. That is, the component force of the compressive force 42b goes inward in the radial direction of the push-in hole 40a.

Due to the component force of the compressive force 42a inward in the radial direction, the inner peripheral wall of the body 20a or the body 10 after passing through the tapered surface 44 is the outer surface of the punch 41 located on the extension line of the tapered surface 44. Is pressed against. As a result, the inner peripheral wall of the body 20a or the body 10 is formed without a gap with the outer surface of the punch 41, and the inner dimensions of the body 20a or the body 10 are the shape transferred from the shape of the punch 41. Become. As a result, the roundness of the inner diameter of the body portion 10 can be satisfied without finishing ironing, and problems such as the generation of plating slag due to finishing ironing can be avoided.

The smaller the inclination angle θ of the tapered surface 44 and the steeper the tapered surface 44, the more the inflow of the body body 20a into the inner side of the push-in hole 40a is promoted. However, when the inclination angle θ of the tapered surface 44 is small, it is necessary to design the die 40 vertically long in order to make the inlet inner diameter 40b of the push-in hole 40a equal to or larger than the peripheral wall outer diameter of the body body 20a before compression drawing. There is and it becomes long. On the other hand, when the inclination angle θ of the tapered surface 44 is large, the inflow of the body body 20a into the inner side of the push-in hole 40a may be hindered, and the dimensional accuracy may decrease.

As will be specifically described later, when the inclination angle of the tapered surface 44 with respect to the axial direction of the push-in hole 40a is θ (°), θ is determined so as to satisfy the relationship of the following equation (1). Is preferable.
20 ° ≤ θ ≤ 60 ° ・・・・・ Equation (1)
By setting 20 ° ≦ θ, even if the compressive force of the lifter pad 42 is increased, it is possible to prevent the plate thickness of the peripheral wall of the body portion from becoming excessively thick. On the other hand, when θ ≦ 60 °, the accuracy of the inner diameter dimension and the inner diameter roundness can be improved even when the compressive force by the lifter pad 42 is small. The axial direction of the push-in hole 40a can be understood as the push-in direction of the body body 20a or the advance / retreat direction of the punch 41.

Further, the value obtained by dividing the compressive force 42a applied to the body body 20a by the cross-sectional area of the peripheral wall of the body body 20a is defined as the compression pressure P (unit: N / mm ² ) with respect to the axial direction of the push-in hole 40a. When the inclination angle of the tapered surface 44 is θ (°), it is preferable that P is determined so as to satisfy the relationship of the following equation (2) or equation (3) according to θ. The cross-sectional area of the peripheral wall of the body body 20a can be calculated by any method, but the average plate thickness of the peripheral wall of the body body 20a related to the height direction before each compression drawing is used. It may be calculated.
55 ≤ P ≤ 0.99 θ + 123 (20 ° ≤ θ ≤ 45 °) ・・・・・ Equation (2)
2.47 θ-56 ≤ P ≤ 0.99 θ + 123 (45 ° <θ ≤ 60 °) ・・・・・ Equation (3)
By determining P in this way, it is possible to more reliably avoid the occurrence of defects such as breakage or plating slag.

(Example)
Next, an example will be shown. The present inventors compress a circular plate having a thickness of 1.8 mm, a plating adhesion amount of 90 g / m ² , and a diameter of 116 mm, which is a cold-rolled ordinary steel sheet coated with Zn-Al-Mg, as a material metal plate 2. The relationship between the magnitude of the force 42a and the average thickness (mm) of the peripheral wall of the body of the body 20a was investigated. In addition, the inner diameter and the roundness of the inner diameter of various body elements 20a produced by changing the compressive force 42a in the compression drawing step and the normal wall thinning process in which no compressive force was applied (Comparative Example 1) were investigated. The processing conditions at that time are shown in Table 1.

FIG. 8 is a graph showing the plate thickness distribution of the body portion 10 after the third compression drawing is completed, and shows the compression pressure applied by the lifter pad 42 during the first to third compression drawing and the peripheral wall plate thickness of the body portion 10. The relationship with the distribution is shown. FIG. 9 is an explanatory view showing a plate thickness measurement position of FIG. In FIG. 8, the vertical axis is the peripheral wall plate thickness of the body portion 10 after the third compression drawing, and the horizontal axis is the plate thickness measurement position of the peripheral wall of the body portion 10. The compressive force at the time of the first to third compression drawing was constant, and the plate thickness was measured in a direction parallel to the material rolling direction.

As shown in FIG. 8, the peripheral wall plate thickness of the body portion 10 increases as a whole as the compression pressure in the first to third compression drawing steps increases. When the compression pressure is 92 N / mm ² or more, the material plate thickness (1.8 mm) or more is obtained except for the vicinity of the shoulder (measurement position: 5 mm position). In addition, by setting the compression pressure to 147 N / mm ² or more, the plate thickness of the peripheral wall of the body except for the upper part (measurement position: 5 mm to 10 mm position) is the clearance of the die (die 40 and punch) in the third compression drawing process. The size of the mold gap of 41) has been reached.

FIG. 10 is a graph showing the relationship between the compression pressure applied by the lifter pad 42 in the first to third compression drawing steps and the inner diameter of the body portion 10 after the third compression drawing. The inner diameter dimension measurement position is shown in FIG. As the material metal plate 2, a Zn-Al-Mg plated steel sheet having a plate thickness of 1.8 mm was used as in FIG. 8, and the compression pressure at the time of the first to third compression drawing was kept constant. The product standard was 36.15 mm ± 0.05 mm. It can be seen that the inner diameter of the body tends to decrease as the compression pressure increases, and when a compression pressure of 147 N / mm ² or more is applied, the inner diameter becomes substantially equal to or less than the punch diameter at the time of the third drawing. This is consistent with the compression pressure shown in FIG. 8 where the peripheral wall plate thickness of the body portion 10 reaches the mold clearance in the third compression drawing step except for the upper part (measurement position: 5 mm to 10 mm position). .. From this, when a compression pressure of 147 N / mm ² or more is applied in the first to third compression drawing steps, the thickness of the peripheral wall plate of the body 10 is increased and the material is filled in the mold, so that the body is filled. Since the peripheral wall of 10 is formed on the punch and the die without a gap, the inner diameter is reduced.

On the other hand, compared to the inner diameter of the 0N / mm ² without applying a compressive force by the lifter pads 42, the inner diameter is smaller in the case of applying a compressive pressure of ^{55N / mm 2 ~ 129N / mm} 2. As shown in FIG. 8, since the peripheral wall plate thickness of the body portion 10 in this case is equal to or less than the clearance of the die in the third compression drawing step, the small inner diameter means that the peripheral wall of the body portion 10 and the punch There is almost no gap, indicating that there is a gap between the peripheral wall of the body 10 and the die 40. At the measurement position of 15 mm, the difference between the inner diameter and the punch diameter, that is, the clearance between the peripheral wall of the body 10 and the punch diameter is less than half by applying a compression pressure of 55 N / mm ² , and the peripheral wall plate of the body 10 Even if the thickness is less than the mold clearance, the inner diameter standard can be satisfied.

FIG. 11 is a graph showing the relationship between the compression pressure applied by the lifter pad in the first to third compression drawing steps and the roundness of the inner diameter of the body after the third compression drawing. The roundness of the inner diameter was measured using a contact-type three-dimensional coordinate measuring machine (SVA600A-C2 manufactured by Tokyo Seimitsu Co., Ltd.). The molded product was non-destructive, and a carbide shaft stylus having a ball diameter of 4 mm was used. At an arbitrary height with respect to the depth direction of the body body 20a, the coordinates of 16 points are measured at a pitch of 22.5 degrees in the circumferential direction inside the body body 20a, and a circular body is extracted from these measurement points. The roundness of the inner diameter was derived. The roundness of the inner diameter means that the inner wall shape of the body body 20a at an arbitrary height in the depth direction is a circular shape, and when this circular shape is sandwiched between two concentric circles, the distance between the two concentric circles is the minimum. It is represented by the difference in radius of two circles when The product standard for roundness of the inner diameter is 0.02 mm or less. As the material metal plate 2, a Zn-Al-Mg plated steel sheet having a plate thickness of 1.8 mm was used as in FIG. 8, and the compressive force at the time of the first to third compression drawing was kept constant.

The roundness of the inner diameter of 0 N / mm ² without applying compressive force is 0.04 mm or more at the measurement positions of 15 mm and 30 mm, which is out of the product standard. On the other hand, when the compression pressure is 55 N / mm ² or more, the roundness of the inner diameter is less than half at any compression pressure, which is 0.02 mm or less, which is the product standard. This is because the space between the material and the punch 41 is formed without a gap by applying a compression pressure of 55 N / mm ² or more, and the inside of the peripheral wall of the body portion 10 transfers the punch shape and approaches a perfect circular shape.

Tables 2 to 6 are experimental results showing the moldable range in the present invention. As the material metal plate 2, a circular plate having a thickness of 1.8 mm, a plating adhesion amount of 90 g / m2, and a diameter of 116 mm, which was obtained by plating a cold-rolled ordinary steel sheet with Zn-Al-Mg, was used. The inclination angle θ of the tapered surface 44 with respect to the axial direction of the push-in hole 40a was changed from 20 ° to 70 °, and evaluated by the inner diameter dimension, the inner diameter roundness, the presence or absence of plating residue, and the presence or absence of breakage. The product standard is that the inner diameter dimension is 36.15 ± 0.05 mm and the inner diameter roundness is 0.02 mm or less, and if all the measurement positions (15 mm, 30 mm, 45 mm) in the depth direction satisfy the product standard, ○, If even one place deviates from the product standard, it is indicated as x. The presence or absence of breakage is the result of pressing the cylindrical processed product formed in the first to third compression drawing steps using a mold simulating a motor case. Regarding the propriety of molding, those satisfying all the evaluation items are indicated by ○ in the evaluation column in the figure, and those that are out of order are indicated by ×.

When the inclination angle θ of the tapered surface 44 is 45 ° (Table 4), the compression pressure range by the moldable lifter pad 42 is the widest, and the lifter pad 42 of 55 N / mm ² or more at the time of the first to third compression drawing By applying compression pressure, the inner diameter dimension and inner diameter roundness satisfy the product standard. When a compression pressure of 184 N / mm ² or more was applied, the peripheral wall of the body became excessively thick with respect to the clearance of the simulated mold, and the inflow resistance of the peripheral wall of the body into the die increased, causing breakage at the top of the processed product. ..

Regarding the effect of the inclination angle θ of the tapered surface 44 on the moldable range, when the inclination angle θ of the tapered surface 44 is small, the inflow of the peripheral wall of the body portion into the die 40 is promoted during the first to third compression drawing, and the body The thickness of the peripheral wall becomes thicker. Therefore, when the compressive force of the lifter pad 42 becomes large, the plate thickness becomes excessively thick, and the surface pressure of the mold and the peripheral wall of the body becomes large. At this time, plating slag is generated, the inflow resistance of the peripheral wall of the body into the die 40 is increased, and breakage is likely to occur in the top wall 100 and its vicinity. Therefore, the lower limit of the inclination angle θ of the tapered surface 44 is preferably 20 °. However, when the inclination angle θ of the tapered surface 44 is 20 °, it is necessary to design the mold to be vertically long.

On the other hand, when the inclination angle θ of the tapered surface 44 is large, the inflow of the peripheral wall of the body into the die 40 is hindered during the first to third compression drawing, and the peripheral wall of the body passes through the region 47 of the tapered surface 44. , It may be formed without contacting the side surface of the punch 41 on the extension line of the tapered surface 44. Therefore, in the range where the compressive force by the lifter pad 42 is small, the inner diameter dimension and the inner diameter roundness deviate from the product standard, and when the inclination angle θ of the tapered surface 44 is 70 ° (Table 6), it deviates from the standard at any compression pressure. Was there. Therefore, the inclination angle θ of the tapered surface 44 is preferably determined so as to satisfy the following equation (1).

20 ° ≤ θ ≤ 60 ° ... Equation (1)

FIG. 12 shows the moldable range shown in Tables 2 to 6, the inclination angle θ of the tapered surface 44, and the compression pressure P (compressive force in the depth direction received from the lifter pad 42 in the cross-sectional area of the peripheral wall of the body body 20a. It is explanatory drawing which showed the relationship (value divided by). Items that satisfy all of the items are indicated by ○ in the figure, items with breakage or plating slag are indicated by ×, and items whose inner diameter dimension or inner diameter roundness does not satisfy the product standard are indicated by ▲. From the result of FIG. 12, the value obtained by dividing the compressive force applied to the body body 20a by the cross-sectional area of the peripheral wall of the body body 20a is defined as P (unit: N / mm ² ), and the axial direction of the push-in hole 40a. When the inclination angle of the tapered surface 44 with respect to the taper surface 44 is θ (°), it is preferable to determine P so as to satisfy the relationship of the following equation (2) or equation (3) according to θ.
55 ≤ P ≤ 0.99 θ + 123 (20 ° ≤ θ ≤ 45 °) ... Equation (2)
2.47 θ-56 ≤ P ≤ 0.99 θ + 123 (45 ° <θ ≤ 60 °) ... Equation (3)

According to such a molding material manufacturing method and a molding die, the component force of the compressive force is directed inward in the radial direction of the push-in hole 40a due to the tapered surface 44, so that the peripheral wall of the body body 20a is formed during the compression drawing. It can be pressed against the punch 41, and the inner peripheral surface of the body 20a or the body 10 can be formed on the outer peripheral surface of the punch 41 without any gap. As a result, the roundness of the inner diameter of the body portion 10 can be improved without finishing and ironing. Since no finishing ironing process is required, the load on the material surface and the mold is reduced, and it is possible to avoid the occurrence of plating slag and galling. This configuration is particularly useful in applications where highly accurate inner diameter roundness is required for molding materials such as motor cases.

Further, when the inclination angle of the tapered surface 44 with respect to the axial direction of the push-in hole 40a is θ (°), θ is determined so as to satisfy the relationship of 20 ° ≤ θ ≤ 60 °, so that the compression pressure by the lifter pad 42 However, it is possible to prevent the plate thickness of the peripheral wall of the body from becoming excessively thick, and it is possible to improve the accuracy of the inner diameter dimension and the inner diameter roundness even when the compression pressure by the lifter pad 42 is small. ..

Further, the value obtained by dividing the compressive force applied to the body body 20a by the cross-sectional area of the peripheral wall of the body body 20a is defined as P (unit: N / mm ² ), and the tapered surface 44 in the axial direction of the push-in hole 40a. When the inclination angle of is θ (°), P is determined so as to satisfy the relationship of the following equation (2) or equation (3) according to θ, so that there is a problem such as breakage or plating slag. The occurrence can be avoided more reliably.
55 ≤ P ≤ 0.99 θ + 123 (20 ° ≤ θ ≤ 45 °) ・・・・・ Equation (2)
2.47 θ-56 ≤ P ≤ 0.99 θ + 123 (45 ° <θ ≤ 60 °) ・・・・・ Equation (3)

Further, since the bearing force that supports the pad portion 420 can be adjusted, the compression pressure in the first to third compression drawing steps should be adjusted within an appropriate pressure range regardless of the thickness of the material metal plate. It is possible to perform drawing processing that satisfies the inner diameter roundness with high accuracy and stability.

Although it is explained that the compression drawing process is performed three times in the embodiment, the number of compression drawing processes may be appropriately changed according to the size of the molding material 1 and the required dimensional accuracy.

Further, in the embodiment, the supporting force for supporting the pad portion 420 has been described so as to be adjustable, but the supporting force for supporting the pad portion 420 may not be adjustable.

Claims

A molding material manufacturing method including manufacturing a molding material having a tubular body portion and a flange portion formed at an end portion of the body portion by performing multi-stage drawing on a material metal plate.
For the multi-stage aperture,
A preliminary drawing that forms a spare body having a body body from the material metal plate, and
A die having a push-in hole, a punch inserted inside the body of the body to push the body into the push-hole, and a compressive force along the depth direction of the body of the body are applied to the body. The body is squeezed by squeezing the body while applying the compressive force to the body, which is performed after the preliminary drawing using a mold including a pressurizing means applied to the peripheral wall of the body. With at least one compression squeeze to form
Is included,
The push-in hole extends in the circumferential direction of the push-in hole at the entrance of the push-in hole, and also has a tapered surface extending in an inclined direction with respect to the axial direction of the push-in hole, and the tapered surface extends. A molding material manufacturing method in which the component force of the compressive force is configured to be directed inward in the radial direction of the push-in hole.
The inner diameter of the inlet of the push-in hole is equal to or larger than the outer diameter of the peripheral wall of the body body before compression drawing performed by using the die having the push-in hole.
When the inclination angle of the tapered surface with respect to the axial direction of the push-in hole is θ (°), θ is determined so as to satisfy the relationship of the following equation (1) 20 ° ≤ θ ≤ 60 ° ...・・ Equation (1)
The molding material manufacturing method according to claim 1.
The value obtained by dividing the compressive force applied to the body of the body by the cross-sectional area of the peripheral wall of the body of the body is defined as the compression pressure P (unit: N / mm 2 ), and the taper with respect to the axial direction of the push-in hole. When the inclination angle of the surface is θ (°)
P is determined so as to satisfy the relationship of the following equation (2) or equation (3) according to θ. 55 ≤ P ≤ 0.99 θ + 123 (20 ° ≤ θ ≤ 45 °) (2)
2.47 θ-56 ≤ P ≤ 0.99 θ + 123 (45 ° <θ ≤ 60 °) ・・・・・ Equation (3)
The molding material manufacturing method according to claim 1 or 2.
The pressurizing means is arranged at an outer peripheral position of the punch so as to face the die, and supports the pad portion on which the lower end of the peripheral wall of the body of the body is placed and the pad portion from below. It is a lifter pad having an urging portion configured so that the supporting force for supporting the pad portion can be adjusted.
The at least one compression drawing is performed so that the pad portion is completed before reaching bottom dead center.
When the compression drawing of the body body is performed, the bearing force acts on the body body as the compression force.
The molding material manufacturing method according to any one of claims 1 to 3.
A molding die for drawing a spare body having a body body.
With a die with a push-in hole
A punch that is inserted inside the body and pushes the body into the push-in hole.
It is provided with a pressurizing means for applying a compressive force along the depth direction of the body body to the peripheral wall of the body body.
It is configured to squeeze the body while applying the compressive force to the body.
The push-in hole extends in the circumferential direction of the push-in hole at the entrance of the push-in hole, and also has a tapered surface extending in an inclined direction with respect to the axial direction of the push-in hole, and the tapered surface extends. A molding die configured so that the component force of the compressive force is directed inward in the radial direction of the push-in hole.
The inner diameter of the inlet of the push-in hole is equal to or larger than the outer diameter of the peripheral wall of the body body before compression drawing performed by using the die having the push-in hole.
When the inclination angle of the tapered surface with respect to the axial direction of the push-in hole is θ (°), θ is determined so as to satisfy the relationship of the following equation (1) 20 ° ≤ θ ≤ 60 ° ...・・ Equation (1)
The molding die according to claim 5.
The value obtained by dividing the compressive force applied to the body of the body by the cross-sectional area of the peripheral wall of the body of the body is defined as the compression pressure P (unit: N / mm 2 ), and the taper with respect to the axial direction of the push-in hole. When the inclination angle of the surface is θ (°)
P is determined so as to satisfy the relationship of the following equation (2) or equation (3) according to θ. 55 ≤ P ≤ 0.99 θ + 123 (20 ° ≤ θ ≤ 45 °) (2)
2.47 θ-56 ≤ P ≤ 0.99 θ + 123 (45 ° <θ ≤ 60 °) ・・・・・ Equation (3)
The molding die according to claim 5 or 6.
The pressurizing means is arranged at an outer peripheral position of the punch so as to face the die, and supports the pad portion on which the lower end of the peripheral wall of the body of the body is placed and the pad portion from below, and the above-mentioned. It is a lifter pad having an urging portion configured so that the supporting force for supporting the pad portion can be adjusted.
The at least one compression drawing is performed so that the pad portion is completed before reaching bottom dead center.
When the compression drawing of the body body is performed, the bearing force acts on the body body as the compression force.
The molding die according to any one of claims 5 to 7.