Patent Description:
A plate-shaped rolled steel plate is supplied between an upper mold and a lower mold of a press apparatus from a flatted and rolled state, and is punched into a predetermined shape by a cooperation of the upper mold slidable up and down and the lower mold. Then, a rotating-layering mold is used for laminating the punched plate-shaped rolled steel sheets to form a rotor, a stator, or the like, called a motor core. By the way, the rolled steel plate has the slightly different thickness in the width direction since the pressure at the supporting portions of the rolling rollers at both ends in the width direction and the pressure at the central portion of the rolling roller at the center in the width direction are different during rolling. Therefore, when the rolled steel plate supplied to the press apparatus is punched by the upper mold and the lower mold, and the punched plate-shaped rolled steel sheets are laminated as they are, thick portions of the punched plate-shaped rolled steel sheets are laminated to one another and thin portions of the punched plate-shaped rolled steel sheets are laminated to one another. Thus, while such a laminated member has a thick portion formed by laminating the thick portions to one another, the member has a thin portion formed by laminating the thin portions to one another, and the shape of the member is thus inclined. If such an inclined member is used as the rotor and the stator, the performance of the motor may be deteriorated. Therefore, in order not to incline the laminated member, the plate-shaped rolled steel sheets punched by the rotating-layering mold are rotated according to a predetermined angle so as to laminate them.

In recent years, motors are often used in mechanical devices, automobiles, or the like, and the demand for the motors is increasing. As a result, the demand for motor cores such as rotors and stators that configure the motors is also increasing, and it is required to improve the manufacturing efficiency for the motor cores. In order to improve the manufacturing efficiency, a rotating-layering mold capable of rotating the punched plate-shaped rolled steel sheets at high speed so as to laminate them is required. Also, when the plate-shaped rolled steel plate supplied to the press apparatus is punched into a predetermined shape by the cooperation of the upper mold and the lower mold, a thrust load is generated in the vertical direction in the rotating-layering mold. In particular, when punching at high speed in order to improve the manufacturing efficiency, the thrust load becomes more noticeable and is transmitted to the rotating-layering mold, reducing the rotation accuracy of the rotating-layering mold and decreasing the manufacturing accuracy for the motor cores. Further, in order to rotate the rotating-layering mold, for example, when a rotation of a drive unit is transmitted to the rotating-layering mold by a timing belt, a radial load due to a tension (tensile force) of the timing belt coupling the rotating-layering mold and the drive unit is generated. In particular, when rotating at high speed in order to improve the manufacturing efficiency, it is necessary to increase the tension of the timing belt, and the radial load due to the tension inclines the posture of the rotating-layering mold, reducing the rotation accuracy of the rotating-layering mold and decreasing the manufacturing accuracy for the motor cores. Therefore, the rotating-layering mold which is not affected by the thrust load in the vertical direction and the radial load in the horizontal direction is required.

Patent Literature <NUM> discloses a laminated core manufacturing apparatus of manufacturing laminated cores by punching steel sheet pieces from an electromagnetic steel plate so as to laminate them, including an upper mold including an contour punch, a lower mold including a squeeze ring fixed to an contour punch die corresponding to the contour punch and extending downward, and an index device of driving the squeeze ring to rotate intermittently. The squeeze ring is rotatably supported by the lower mold via a plurality of bearings, and the steel sheet pieces that are sequentially punched and are dropped from an upper end opening into the interior are held in a laminated state.

Patent Literature <NUM> (<CIT>) discloses a rotating-layering unit having a mold holder equipped with a mold mounting portion where a lower mold is attached, the mold mounting portion of rotating, at a predetermined angle, plate materials punched by a cooperation of an upper mold and the lower mold so as to laminate them, and a part accommodating portion of accommodating the punched plate-shaped parts, and a holder support member having an inner peripheral surface surrounding an outer peripheral surface of the mold holder, the holder support member of rotatably supporting the mold holder. A cross roller bearing is configured to interpose a plurality of rolling elements which roll in contact with a first V-shaped groove formed on the outer peripheral surface of the mold holder and a second V-shaped groove formed on the inner peripheral surface of the holder support member between the mold holder and the holder support member.

<CIT> discloses a laminated iron core manufacturing apparatus including a die arranged facing a punch, a squeeze ring directly under the die and holding iron core pieces punched by the punch and the die, a die holder holding the die and the squeeze ring, and a motor having a stator and a rotor and rotationally driving the die holder. The die holder is rotatably supported via a radial bearing and a thrust bearing.

The squeeze ring disclosed in Patent Literature <NUM> is rotatably supported by the lower mold via two upper and lower bearings. However, these two upper and lower bearings cannot support the squeeze ring so as not to be affected by all of the thrust load in the vertical direction and the radial load in the horizontal direction, whereby there is a problem that the rotation accuracy of the squeeze ring is reduced and the manufacturing accuracy for the motor cores is decreased.

In the rotating-layering unit disclosed in Patent Literature <NUM>, in order not to cause permanent deformation of the cross roller bearing due to the downward load that acts on the mold holder when the plate materials are punched, a space between a top of the mold holder and the holder support member must be smaller than a relative movement amount, which causes permanent deformation of the cross roller bearing when the plate materials are punched, between the mold holder and the holder support member, whereby there is a problem that it is prevented from improving the manufacturing efficiency of the rotating-layering unit.

Therefore, an object of the present invention is to solve the above problems, to make it less susceptible to be affected by the thrust load in the vertical direction and the radial load in the horizontal direction, and to provide the rotating-layering mold of rotating, according to a predetermined angle, the plate materials punched by the cooperation of the upper mold and the lower mold so as to laminate the plate materials and the press apparatus including the rotating-layering mold.

According to an aspect of the present invention, a rotating-layering mold of rotating, according to a predetermined angle, plate materials punched by a cooperation of an upper mold and a lower mold so as to laminate the plate materials includes a squeeze ring provided with a holding hole of holding the punched plate materials. The squeeze ring is configured to rotate with respect to the lower mold such that an outer peripheral surface of the squeeze ring lies along an inner peripheral surface of the lower mold. The rotating-layering mold further includes a first thrust bearing, a second thrust bearing, and a radial bearing in order to support the rotation of the squeeze ring with respect to the lower mold.

According to a specific example of the present invention, in the rotating-layering mold, the radial bearing is arranged between the first thrust bearing and the second thrust bearing.

According to a specific example of the present invention, the rotating-layering mold includes a first inner ring portion and a second inner ring portion, and the first thrust bearing, the second thrust bearing, and the radial bearing are arranged between the first inner ring portion and the second inner ring portion.

According to a specific example of the present invention, in the rotating-layering mold, the first inner ring portion and the second inner ring portion are fastened such that the first thrust bearing and the second thrust bearing are in a preloaded state.

According to a specific example of the present invention, in the rotating-layering mold, the rotation of the squeeze ring is guided by a guide configured with a second outer ring portion fixed to the lower mold and the lower mold.

According to a specific example of the present invention, in the rotating-layering mold, in a state where a gap is generated between the guide and the squeeze ring, the first thrust bearing and the second thrust bearing are in the preloaded state.

According to a specific example of the present invention, in the rotating-layering mold, the first thrust bearing is configured with a first outer ring portion fixed to the lower mold, the first inner ring portion, and rolling elements, the second thrust bearing is configured with the first outer ring portion, the second inner ring portion, and rolling elements, and the radial bearing is configured with the first outer ring portion, the first inner ring portion or the second inner ring portion, and rolling elements.

According to a specific example of the present invention, in the rotating-layering mold, the rolling elements of the first thrust bearing, the rolling elements of the second thrust bearing, and the rolling elements of the radial bearing are arranged radially inward with respect to the outer peripheral surface of the squeeze ring.

According to a specific example of the present invention, the rotating-layering mold further includes a driven pulley fixed to the squeeze ring.

According to another aspect of the present invention, the press apparatus including the above rotating-layering mold includes a drive unit including a motor having a output shaft to rotate, a drive pulley fixed to the output shaft, and a transmission member of transmitting the rotation of the drive pulley based on the rotation of the output shaft to the driven pulley and rotating the squeeze ring according to the predetermined angle.

According to the present invention, since the squeeze ring can be supported so as not to be affected by a thrust load with respect to the vertical direction of up and down and a radial load with respect to the horizontal direction, the rotation accuracy of the squeeze ring can be improved and the manufacturing accuracy for the motor cores can be improved.

Other objects, features and advantages of the present invention will become apparent from the following description of the embodiments of the present invention taken in conjunction with the accompanying drawings.

Embodiments according to the present invention will be described with reference to the drawings. However, the present invention is not limited to those embodiments but the scope of the invention is limited by the appended claims.

An embodiment of a rotating-layering mold and a press apparatus of the present invention will be described with reference to <FIG>.

<FIG> shows a schematic view of a press apparatus <NUM> including a rotating-layering mold <NUM> and a drive unit <NUM> as an embodiment of the present invention as seen from the front. The press apparatus <NUM> includes a slide member <NUM> that is slidable in the vertical direction with respect to a main body frame of the press apparatus <NUM>, an upper mold guide member <NUM> that is installed on the main body frame and slidably guides the slide member <NUM>, an upper mold <NUM> installed on a lower surface of the slide member <NUM>, and a lower mold <NUM> fixed to a housing <NUM> installed on the main body frame. In the press apparatus <NUM>, a rolled steel plate <NUM> as a plate material is supplied between the upper mold <NUM> and the lower mold <NUM>, and the slide member <NUM> slides downward via the upper mold guide member <NUM>. The supplied rolled steel sheets <NUM> are punched by a contour punch of the upper mold <NUM> and a contour punching die of the lower mold <NUM> corresponding to this contour punch of the upper mold <NUM>.

When the rolled steel sheets <NUM> are punched and the slide member <NUM> slides in the upward direction, the contour punch of the upper mold <NUM> is drawn from the contour punching die of the lower mold <NUM>, and the punched rolled steel sheets <NUM> are then dropped into a holding hole <NUM> provided in the squeeze ring <NUM> fixed to the contour punching die and are held by a frictional force. Subsequently, the squeeze ring <NUM> rotates such that the punched rolled steel sheets <NUM> held in the holding hole <NUM> are also rotated according to a predetermined angle. By repeating punching and rotating in this manner to sequentially laminate the punched rolled steel sheets <NUM>, a laminated body <NUM> having no inclined shape for use in a motor core such as a rotor and a stator that configure a motor, or the like can be formed. In addition, the angle to rotate the rolled steel sheets <NUM> is not limited. However, for example, the rolled steel sheets <NUM> may be rotated according to the predetermined value such as <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, or the like that can be divided by dividing <NUM>° by an integer so as to sequentially laminate them. Alternatively, the rolled steel sheets <NUM> may be rotated according to the predetermined value such as <NUM>°+<NUM>°, <NUM>°+<NUM>°, or the like that is obtained by adding a minute angle to an angle that can be divided by dividing <NUM>° by an integer so as to sequentially laminate them in a spiral shape having a skew.

<FIG> shows a cross-sectional view of the rotating-layering mold <NUM> of rotating the rolled steel sheets <NUM> punched by the cooperation of the upper mold <NUM> and the lower mold <NUM> according to the predetermined angle so as to laminate them. The rotating-layering mold <NUM> includes the squeeze ring <NUM> that can be accommodated within a cylindrical hole provided in the lower mold <NUM>. The squeeze ring <NUM> can rotate with respect to the lower mold <NUM> such that an upper outer peripheral surface <NUM> of the squeeze ring <NUM> lies along an inner peripheral surface <NUM> of the hole of the lower mold <NUM>. The rotating-layering <NUM> further includes a first thrust bearing (an upper thrust bearing), a second thrust bearing (a lower thrust bearing), and a radial bearing in order to support the rotation of the squeeze ring <NUM> with respect to the lower mold <NUM>. The squeeze ring <NUM> can be supported by the upper thrust bearing and the lower thrust bearing so as not to be affected by a thrust load with respect to the vertical direction of up and down and can be further supported by the radial bearing so as not to be affected by a radial load with respect to the horizontal direction. A position of the radial bearing with respect to the upper thrust bearing and the lower thrust bearing is not particularly limited. However, when the radial bearing is arranged between the upper thrust bearing and the lower thrust bearing, it is possible to compactly configure the rotating-layering mold <NUM> and reduce the cost.

The rotating-layering mold <NUM> includes a first inner ring portion (an upper inner ring portion) <NUM> and a second inner ring portion (a lower inner ring portion) <NUM> fixed to the squeeze ring <NUM>. The upper thrust bearing, the lower thrust bearing, and the radial bearing may be arranged between the upper inner ring portion <NUM> and the lower inner ring portion <NUM>. In addition, although the upper inner ring portion <NUM> and the lower inner ring portion <NUM> are separate components from the squeeze ring <NUM> in <FIG>, the upper inner ring portion <NUM> or the lower inner ring portion <NUM> may be configured to be integrated with the squeeze ring <NUM>.

The upper inner ring portion <NUM> and the lower inner ring portion <NUM> are fastened such that the upper thrust bearing and the lower thrust bearing are in a preloaded state. If there is an internal clearance in the bearing, the rigidity of the bearing becomes low such that the rotation vibration of the squeeze ring <NUM> becomes large, and the axis of the squeeze ring <NUM> tends to tilt. Therefore, a load is applied in the thrust direction in advance so as to eliminate the internal clearance such that preload is applied to the upper thrust bearing and the lower thrust bearing. By applying the preload, it is possible to reduce the vibration and improve the acoustic performance. When the press apparatus <NUM> is operating, that is, when the squeeze ring <NUM> rotates with respect to the lower mold <NUM>, the slide member <NUM> slides in the downward direction such that the rolled steel sheets <NUM> are punched by the contour punch of the upper mold <NUM> and the contour punching die of the lower mold <NUM>, the slide member <NUM> slides in the upward direction such that the contour punch of the upper mold <NUM> is pulled out from the contour punching die of the lower mold <NUM>, and the squeeze ring <NUM> then rotates with respect to the lower mold <NUM> again, it is desirable that the upper inner ring portion <NUM> and the lower inner ring portion <NUM> be fastened such that the upper thrust bearing and the lower thrust bearing are in the preloaded state. Since the upper thrust bearing and the lower thrust bearing are in the preloaded state, the squeeze ring <NUM> can be reliably supported by the upper thrust bearing and the lower thrust bearing so as to rotate without being affected by the thrust load with respect to the vertical direction of up and down, and the rotation accuracy of the squeeze ring <NUM> can be thus improved. In addition, although the upper inner ring portion <NUM> and the lower inner ring portion <NUM> may be fastened by an inner ring portion screw <NUM>, a fastening means is not limited. The magnitude of the preload can be adjusted by the fastening means.

As shown in <FIG> and <FIG>, the upper thrust bearing may be configured with a first outer ring portion (a lower outer ring portion) <NUM> fixed to the lower mold <NUM> via the housing <NUM> by a lower outer ring portion screw <NUM>, the upper inner ring portion <NUM>, and rolling elements <NUM>, each rotating about the axis in the horizontal direction, the lower thrust bearing may be configured with the lower outer ring portion <NUM>, the lower inner ring portion <NUM>, and rolling elements <NUM>, each rotating about the axis in the horizontal direction, and the radial bearing may be configured with the lower outer ring portion <NUM>, the lower inner ring portion <NUM>, and rolling elements <NUM>, each rotating about the axis in the vertical direction. By managing dimension such that the length of a space <NUM> between the upper inner ring portion <NUM> and the lower inner ring portion <NUM> for configuring the upper thrust bearing, the lower thrust bearing, and the radial bearing is smaller than the total length of the outer diameter of the rolling element <NUM>, the thickness of the lower outer ring portion <NUM>, and the outer diameter of the rolling element <NUM>, when the upper inner ring portion <NUM> and the lower inner ring portion <NUM> are fastened, the internal clearance disappears such that the upper thrust bearing and the lower thrust bearing can be in the preloaded state. Then, although the rotating-layering mold <NUM> moves relatively with respect to the lower mold <NUM> when the press apparatus <NUM> is operating, by managing dimension such that a difference between the total length of the outer diameter of the rolling element <NUM>, the thickness of the lower outer ring portion <NUM>, and the outer diameter of the rolling element <NUM> and the length of the space <NUM> is larger than a relative movement amount of the rotating-layering mold <NUM>, the upper thrust bearing and the lower thrust bearing can be in the preloaded state more reliably. In addition, although the lower outer ring portion <NUM> is fixed to the housing <NUM> as a component separate from the housing <NUM> in <FIG>, it may be configured to be integrated with the housing <NUM>. Moreover, a second outer ring portion (an upper outer ring portion) <NUM> is fixed to the lower mold <NUM> via the housing <NUM> by an upper outer ring portion screw <NUM>. However, the upper outer ring portion <NUM> may be also configured to be integrated with the housing <NUM>.

The rotation of the squeeze ring <NUM> may be guided by a guide <NUM> configured with the lower mold <NUM>, the housing <NUM>, and the upper outer ring portion <NUM> fixed to the lower mold <NUM> via the housing <NUM>. The squeeze ring <NUM> includes a guide receiving portion <NUM>, and the guide receiving portion <NUM> is accommodated in the guide <NUM> to guide the rotation of the squeeze ring <NUM> with respect to the lower mold <NUM>. A gap may be provided between a lower surface <NUM> of the lower mold <NUM> and an upper surface <NUM> of the guide receiving portion <NUM> such that the lower mold <NUM> and the guide receiving portion <NUM> do not come into contact with each other. Moreover, a gap may be provided between an upper surface <NUM> of the upper outer ring portion <NUM> and a lower surface <NUM> of the guide receiving portion <NUM> such that the upper outer ring portion <NUM> and the guide receiving portion <NUM> do not come into contact with each other.

Moreover, in a state where a gap is generated between the guide <NUM> and the squeeze ring <NUM>, that is, a gap is generated between the lower surface <NUM> of the lower mold <NUM> and the upper surface <NUM> of the guide receiving portion <NUM>, and a gap is generated between the upper surface <NUM> of the upper outer ring portion <NUM> and the lower surface <NUM> of the guide receiving portion <NUM>, it is desirable that the first thrust bearing and the second thrust bearing be in the preloaded state. If these gaps do not exist, that is, if the guide receiving portion <NUM> contacts the lower mold <NUM> and the upper outer ring portion <NUM>, the squeeze ring <NUM> can be prevented from moving relatively upward and downward with respect to the lower mold <NUM>, and the upper thrust bearing and the lower thrust bearing can be in the preloaded state, when the press apparats <NUM> is operating. However, it is not preferable since the guide receiving portion <NUM>, the lower mold <NUM>, and the upper outer ring portion <NUM> are worn.

The rolling elements <NUM> of the upper thrust bearing, the rolling elements <NUM> of the lower thrust bearing, and the rolling elements <NUM> of the radial bearing may be arranged radially inward with respect to the upper outer peripheral surface <NUM> of the squeeze ring <NUM> that lies along the inner peripheral surface <NUM> of the lower mold <NUM>. When the press apparatus <NUM> is operating, the squeeze ring <NUM> moves relatively upward and downward with respect to the lower mold <NUM>. However, when any portion of the rolling elements <NUM> to <NUM> is radially outward with respect to the upper outer peripheral surface <NUM>, since the thrust load applied to the rolling elements <NUM> to <NUM> changes with the upper outer peripheral surface <NUM> as a boundary, the rolling elements <NUM> to <NUM> may be damaged, and raceways of the rolling elements <NUM> to <NUM> of the lower outer ring portion <NUM>, the upper inner ring portion <NUM>, and the lower inner ring portion <NUM> may be damaged. When the rolling elements <NUM> to <NUM> are arranged radially inward with respect to the upper outer peripheral surface <NUM>, since the thrust loads applied to the rolling elements <NUM> to <NUM> are the same, it is possible to prevent the rolling elements <NUM> to <NUM> from being damaged and prevent the raceways of the rolling elements <NUM> to <NUM> from being damaged.

As shown in <FIG>, the rotating-layering mold <NUM> may include a driven pulley <NUM> fixed to a lower outer peripheral surface <NUM> of the squeeze ring <NUM>. Then, as shown in <FIG>, the press apparatus <NUM> including the rotating-layering mold <NUM> may include the drive unit <NUM> including a motor <NUM> having an output shaft <NUM> to rotate which are fixed to a fixed surface <NUM> which is a side surface of the main body frame of the press apparatus <NUM>, a drive pulley <NUM> fixed to the output shaft <NUM>, and a transmission member <NUM> of transmitting the rotation of the drive pulley <NUM> based on the rotation of the output shaft <NUM> to the driven pulley <NUM> to rotate the squeeze ring <NUM> according to the predetermined angle. The output shaft <NUM> of the motor <NUM> of the drive unit <NUM> rotates according to a predetermined angle, and the rotation is transmitted to the squeeze ring <NUM> via the drive pulley <NUM>, the transmission member <NUM>, and the driven pulley <NUM> such that the squeeze ring <NUM> can be supported by the upper thrust bearing, the lower thrust bearing, and the radial bearing so as to rotate, according to the predetermined angle, with respect to the lower mold <NUM>. In addition, the driven pulley <NUM> and the drive pulley <NUM> may be timing pulleys. Moreover, the transmission member <NUM> may be a timing belt as long as it can transmit the rotation.

As shown in <FIG>, when the transmission member <NUM> is, for example, a timing belt, the radial load is generated in the horizontal direction by the tension of the timing belt of coupling the driven pulley <NUM> and the drive pulley <NUM>, and in particular, when the squeeze ring <NUM> is rotated at high speed, the tension of the timing belt is increased such that more radial load is generated in the horizontal direction. As shown in <FIG>, by configuring the radial bearing with the lower outer ring portion <NUM>, the lower inner ring portion <NUM>, and the rolling elements <NUM>, since the squeeze ring <NUM> is not affected by the radial load due to the tension of the timing belt, and the posture of the squeeze ring <NUM> is not inclined in the direction of the tension, it is possible to improve the rotation accuracy of the squeeze ring <NUM> and improve the manufacturing accuracy for the motor cores. In addition, the radial bearing may be configured with the upper inner ring portion <NUM> instead of the lower inner ring portion <NUM>, and the upper inner ring portion <NUM> or the lower inner ring portion <NUM> may be configured to be integrated with the squeeze ring <NUM>.

Moreover, the drive unit <NUM> may include a rotation angle sensor clamped to the output shaft <NUM> such that a rotation angle of the output shaft <NUM> can be detected. Examples of the rotation angle sensor include, for example, a magnetic resolver and an optical encoder. The drive unit <NUM> may include a control apparatus that receives a signal regarding the rotation angle of the output shaft <NUM> detected by the rotation angle sensor. The control apparatus can determine whether or not the detected rotation angle of the output shaft <NUM> corresponds to a predetermined rotation angle to index with accuracy the rotation angle of the squeeze ring <NUM> that rotates via the transmission member <NUM>.

Claim 1:
A rotating-layering mold (<NUM>) of rotating, according to a predetermined angle, plate materials (<NUM>) punched by a cooperation of an upper mold (<NUM>) and a lower mold (<NUM>) so as to laminate the plate materials (<NUM>), wherein the rotating-layering mold (<NUM>) comprises a squeeze ring (<NUM>) provided with a holding hole (<NUM>) of holding the punched plate materials (<NUM>), characterized in that:
the squeeze ring (<NUM>) is configured to rotate with respect to the lower mold (<NUM>) such that an outer peripheral surface (<NUM>) of the squeeze ring (<NUM>) lies along an inner peripheral surface (<NUM>) of the lower mold (<NUM>); and
the rotating-layering mold (<NUM>) further comprises a first thrust bearing, a second thrust bearing, and a radial bearing in order to support the rotation of the squeeze ring (<NUM>) with respect to the lower mold (<NUM>).