Press punching processing device for core sheets of rotary electric machine

Abstract

To provide a press punching device for core sheets capable of adjusting a position for a punching die of a pilot pin that is inserted into a pilot hole in response to changes in a distance between a position of the pilot hole on the sheet due to changes in a plate thickness of a sheet piece of an electromagnetic steel sheets and a programmed punching position.SOLUTION: A press punching device 1 measures a plate thickness of a sheet piece w before punching processing (2), determines a target position of a pilot pin 7 which is inserted into a pilot hole PH drilled in the sheet piece relative to positions of punching dies on a punch plate and a die plate 4 based on a thickness measurement value, and adjusts a position of the pilot pin so as to match the target position. The target position of the pilot pin is determined so that a distance between a position of the pilot hole changed depending on the plate thickness of the sheet piece and a programmed punching position of the sheet piece, and a distance between the position of the punching die and the position of the pilot pin are matched.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus for forming a rotor core and a stator core of a rotating electrical machine by press-punching magnetic steel sheets into laminated core sheets. [Background technology]

[0002] Rotor cores and stator cores (hereinafter referred to as "motor cores") of rotating electrical machines are typically constructed by laminating core sheets formed by press punching from electromagnetic steel sheets. Various technologies have been proposed related to the formation of such core sheets and the construction of cores. For example, Patent Document 1 proposes a progressive press device that feeds a strip-shaped material and sequentially presses it using multiple presses. To address misalignment of pilot holes punched into the material to determine the press position of the material, the device detects the direction of the load applied to multiple pilot pins that are inserted into the pilot holes and position the material in the presses. When the pilot pins are subjected to a load in the feed direction, the feed amount of the feed means is changed to reduce the load in the feed direction. When the pilot pins are subjected to a load in the width direction of the material, the width direction positioning means changes the width direction position of the pilot pins to reduce the load in the width direction. In Patent Document 2, in order to improve the processing accuracy of laminated electromagnetic steel sheets, it is proposed to press the steel sheets using a press device while fixing the steel sheets to the shaft member by passing the shaft member held by the press device through holes provided in the steel sheets that extend in the lamination direction.Patent Documents 3 and 4 propose positioning mechanisms that prevent deviations in the processing position when press-processing thin plate material without providing pilot holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2019-47689 [Patent Document 2] Patent Publication No. 2019-75935 [Patent Document 3] Patent Publication No. 2006-159205 [Patent Document 4] Patent Publication No. 2007-47689 Summary of the Invention [Problem to be solved by the invention]

[0004] In a press machine for press-punching core sheets for motor cores, typically, pilot holes are first drilled in a piece of electromagnetic steel sheet that will become the core sheet. In the subsequent punching process, pilot pins are inserted into the pilot holes in the sheet between a die plate and a punch plate to position the sheet. In this state, the punch plate presses the sheet toward the die plate, and a die (punching die) with a predetermined pattern perforates or punches the sheet. In this regard, if the thickness of the electromagnetic steel sheet (sheet thickness) is different, the amount of elongation in the surface direction of the sheet when the sheet is pressed between the die plate and the punch plate will differ. As a result, the distance between the position of the pilot hole on the sheet and the position where perforation or punching is to be performed (the planned punching position) will vary depending on the sheet thickness. Therefore, in order to align the intended punching position with the position of the punching die and form the core sheet with high dimensional accuracy, it is preferable that the position of the pilot pin inserted into the pilot hole relative to the position of the punching die can be adjusted to accommodate changes in the distance between the position of the pilot hole and the intended punching position due to the plate thickness.

[0005] Thus, the main object of the present invention is to enable, in a core sheet press punching device, the position of the pilot pin inserted into the pilot hole relative to the position of the punching mold on the die plate and punch plate to be adjusted in response to changes in the distance between the position of the pilot hole on the sheet piece and the intended punching position of a specified pattern due to changes in plate thickness. [Means for solving the problem]

[0006] According to the present invention, the above problem is solved by a punching processing apparatus that punches out a core sheet to be laminated to form a motor core from a sheet piece of electromagnetic steel sheet transported between a punch plate and a die plate, a thickness measuring means for measuring the thickness of the sheet piece before punching; a punching means for punching pilot holes in the sheet piece; a pilot pin target position determining means configured to determine target positions of pilot pins to be inserted into the pilot holes relative to positions of punching dies of a predetermined pattern on the punch plate and the die plate based on the measured plate thickness; a pilot pin position adjusting means for adjusting the position of the pilot pin so that it coincides with a target position of the pilot pin; Including, The pilot pin target position determining means is configured to determine the target position of the pilot pin so that the distance between the position of the pilot hole, which varies depending on the plate thickness, and the position of the sheet piece to be perforated or punched by the punching die coincides with the distance between the position of the punching die and the position of the pilot pin. This is achieved by:

[0007] In the above configuration, the press punching apparatus may be an apparatus having a punch plate and a die plate in a normal manner for punching a core sheet to be stacked to form a motor core, and when a sheet piece of electromagnetic steel sheet is transported between the punch plate and the die plate, the punch plate and the die plate come close to each other, and the punch plate presses the sheet piece against the die plate to punch the sheet piece with a punching die of a predetermined pattern pre-formed on the die plate to form a core sheet. Also, as with a normal apparatus, prior to punching or punching with the punch plate and the die plate, a pilot hole is punched in the sheet piece, and when punching or punching with the punch plate and the die plate, a pilot pin attached to the punch plate is first inserted into the pilot hole to position the sheet piece relative to the punch plate and the die plate. In the case of the present invention, as described above, the thickness of the sheet of electromagnetic steel sheet is measured by the sheet thickness measuring means before punching, and the target positions of the pilot pins relative to the positions of the punching dies of a predetermined pattern on the punch plate and die plate are determined based on the measured sheet thickness, and the actual positions of the pilot pins are adjusted to the target positions by the pilot pin position adjusting means. As already mentioned, when the sheet of electromagnetic steel sheet is pressed between the punch plate and the die plate, the amount of elongation in the surface direction of the sheet varies depending on the sheet thickness, and therefore the distance between the positions of the pilot holes and the intended punching positions varies depending on the sheet thickness. However, in the device of the present invention, the thickness of the sheet is checked prior to punching or piercing the sheet, and the positions of the pilot pins are adjusted so that the distance between the positions of the punching dies on the punch plate and die plate and the position of the pilot pins coincides with the distance between the positions of the pilot holes and the intended punching positions corresponding to the sheet thickness. As a result, in the device of the present invention, the intended punching position on the sheet piece is aligned with the position of the punching die on the punch plate and die plate, allowing perforation or punching to be achieved in the sheet piece with high dimensional accuracy.

[0008] In the above-described configuration of the present invention, the thickness measuring means may be any means for measuring the thickness of the sheet piece.

[0009] With regard to the pilot pin target position determining means, the distance between the position of the pilot hole and the intended punching position on the sheet piece when sheet pieces of various thicknesses are pressed between the punch plate and the die plate (pilot hole-punching position distance) is experimentally investigated in advance, the relationship between the investigated sheet thickness and the pilot hole-punching position distance is stored in the pilot pin target position determining means, and when the sheet piece is perforated or punched with the punching die, the relationship between the sheet thickness and the pilot hole-punching position distance is referenced to determine the pilot hole-punching position distance corresponding to the measured sheet thickness, and the target position of the pilot pin is determined accordingly. The pilot pin target position determining means is realized by the operation of a computer device in accordance with a program.

[0010] The pilot pin position adjusting means is configured to move the position of the pilot pin relative to the positions of the punching dies on the punch plate and the die plate so that the actual position of the pilot pin coincides with the target position of the pilot pin determined by the target pilot pin position determining means. Such a mechanism for moving the position of the pilot pin can be achieved by any mechanism that drives a computer-controlled actuator in response to a control command from the target pilot pin position determining means to displace the pilot pin.

[0011] In the above configuration, the pilot pin may be displaceable forward, backward, left, and right in the sheet piece conveying direction. This allows the position of the pilot pin to be adjusted in response to displacement of the pilot hole and the intended punching position forward, backward, left, and right in the sheet piece conveying direction when the sheet piece has a non-uniform thickness, thereby enabling more accurate perforation or punching of the sheet piece. [Effects of the Invention]

[0012] According to the above-described configuration of the present invention, in the core sheet press punching device, the pilot pin inserted into the pilot hole is displaced to adjust the positional relationship between the punching die and the pilot pin inserted into the pilot hole in response to changes in the distance between the pilot hole and the intended punching position due to differences in the amount of elongation of the sheet piece depending on the sheet thickness of the electromagnetic steel sheet, thereby achieving higher accuracy in forming the core sheet. Furthermore, by performing everything from measuring the sheet thickness to displacing the pilot pin for each sheet piece, higher productivity of the core sheet can be expected.

[0013] Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram of a configuration relating to a displacement mechanism of a pilot pin in a press punching device to which this embodiment is applied. [Figure 2] 2(A) and (B) are schematic diagrams of a sheet piece of electromagnetic steel sheet punched by the press punching device of this embodiment. (A) shows the case where the sheet piece is not elongated in the planar direction, and (B) shows the case where the sheet piece is elongated in the planar direction. However, the amount of elongation is greatly exaggerated for the purpose of explanation. [Explanation of symbols]

[0015] 1...press punching device, 2...sheet piece plate thickness measuring section, 2a...plate thickness measuring point, 3...pilot hole drilling section, 4...die plate, 4a...die, 5...guide rail, 6...pilot pin support base, 7...pilot pin, 8...pilot pin displacement mechanism, 8m...actuator (motor), 10...pilot pin position control section (computer device), w...sheet piece, PH...pilot hole, MH...planned punching position BEST MODE FOR CARRYING OUT THE INVENTION

[0016] The present invention will now be described in detail with reference to some preferred embodiments thereof with reference to the accompanying drawings, in which like reference numerals indicate like parts.

[0017] Device configuration 1, in the press apparatus 1 for performing press punching of a core sheet according to this embodiment, as already described, pilot holes are first drilled in a piece of electromagnetic steel sheet that will become the core sheet, as in the conventional embodiment. When the sheet is transported between the die plate and the punch plate, pilot pins attached to the punch plate are first inserted into the pilot holes to fix the position of the sheet between the die plate and the punch plate. In this state, the punch plate presses the sheet toward the die plate, and perforations or punching is performed using punching dies of a predetermined pattern that are appropriately set in the sheet. In this process, it has been found that if the thickness of the electromagnetic steel sheet changes, the amount of elongation of the sheet during pressing changes, and as a result, the distance between the positions of the pilot holes in the sheet and the planned punching positions where perforations or punching are to be performed in the predetermined pattern changes. Therefore, in this embodiment, a configuration is provided to displace the position of the pilot pin relative to the positions of the punching dies on the die plate and punch plate in response to changes in the distance between the position of the pilot hole and the intended punching position depending on the thickness of the sheet piece.

[0018] More specifically, the apparatus 1 according to this embodiment includes a sheet piece thickness measuring unit 2, a pilot hole punching unit 3, a die plate 4, a punch plate (not shown), and a mechanism 8 for displaceably supporting a pilot pin 7, and a pilot pin position control unit 10. The sheet piece thickness measuring unit 2 is configured to measure the thickness of the sheet piece, i.e., an electromagnetic steel sheet, prior to press working. The specific thickness measurement method may be any suitable method. The measurement position 2a may typically be near both ends and the center of the sheet piece in a direction not perpendicular to the sheet piece conveyance direction. The thickness measurement values ​​t1 to t3 are provided to the pilot pin position control unit 10. The pilot hole punching unit 3 may be configured to punch pilot holes in the conveyed sheet piece with a punch 3a in a conventional manner.

[0019] The die plate 4 and punch plate (not shown) may be configured in a conventional manner, but as shown in the figure, guide rails 5 are provided on the punch plate so as to extend along both edges of the die plate 4 and punch plate. In each of the guide rails 5, a pilot pin support base 6 is installed so as to be slidable in the longitudinal and width directions of the guide rail 5, and a pilot pin 7 is attached to the support base 6 so as to extend perpendicular to the surface of the die plate 4. In addition, each pilot pin support base 6 is provided with a pilot pin displacement mechanism 8 that displaces the position of the pilot pin support base 6 in the longitudinal and width directions of the guide rail 5. Various mechanisms may be used as the displacement mechanism for the support base 6 of the pilot pin displacement mechanism 8. For example, as shown in the figure, a configuration may be employed in which a shaft 8c having a threaded surface is attached to the support base 6, and the threaded surface engages with a threaded surface 8a formed on the rotating shaft of a step motor 8m, which is an actuator, via a gear 8b, so that when the step motor 8m rotates, the rotational motion is converted into linear motion of the support base 6 along the longitudinal and width directions of the guide rail 5. Note that the pilot pin displacement mechanism 8 may be provided for each of the pilot pins 7 on both ends of the die plate 4 and the punch plate, for displacement in the longitudinal and width directions of the guide rail 5, respectively.

[0020] The pilot pin position control unit 10 may be realized by the operation of a computer device according to a program. The pilot pin position control unit 10 is configured to determine the target position of the pilot pin 7 on the guide rail 5 by referring to the measured thickness value from the sheet piece thickness measurement unit 2, and to issue a control command C to the actuator (step motor 8m) of the pilot pin displacement mechanism 8 so that the actual position of the pilot pin 7 coincides with the target position. Regarding the determination of the target position of the pilot pin 7 based on the measured thickness, as explained in the Summary of the Invention section, the position of the pilot hole relative to the intended punching position when the sheet piece is pressed between the die plate and the punch plate in a state where the pilot hole has been punched is experimentally investigated in advance for sheet pieces of various thicknesses, and the relationship between the thickness and the pilot hole position is stored in the pilot pin position control unit 10. When the measured thickness value is input during punching of the core sheet, the position of the pilot hole corresponding to the input thickness is found in the previously investigated relationship between the thickness and the pilot hole position, and the found pilot hole position is adopted as the target position. The target position may be determined for each of the longitudinal direction and the width direction of the guide rail 5.

[0021] Operation of the device As mentioned above, in the press machine of this embodiment, a sheet piece, typically an electromagnetic steel sheet, stretches in the planar direction when pressed between the die plate and the punch plate during punching. The amount of stretching varies depending on the thickness of the sheet piece. Specifically, for example, as shown in FIG. 2(A), if the length of a sheet piece with a certain thickness t assigned to one core sheet is L0 before stretching, when the sheet piece is pressed between the die plate and the punch plate, its length will stretch to L(t), as shown in FIG. 2(B). If the distance between the pilot hole PH and the intended punching position (center) MH before stretching is Y0, the position of the pilot hole PH in the sheet piece stretched during punching will be displaced by Δ(t) from its position before stretching. The amount of displacement Δ(t) of the pilot hole PH position will vary depending on the thickness of the sheet piece. Since the pilot holes are intended to receive pilot pins positioned a predetermined distance from the positions of the punching dies to position the sheet piece so that the intended punching positions of the sheet piece align with the positions of the punching dies on the die plate and punch plate, when the distance between the positions of the pilot holes and the intended punching positions varies depending on the sheet thickness, it is preferable that the position of the pilot pin from the position of the punching dies can also be adjusted by changing the distance between the positions of the pilot holes and the intended punching positions in order to align the intended punching positions with the positions of the punching dies. Thus, in this embodiment, as described above, the sheet thickness of the sheet piece is measured, and the position of the pilot pin is displaced relative to the position of the punching die in accordance with the measured value so that the distance between the position of the pilot pin and the position of the punching die coincides with the distance between the pilot hole PH and the intended punching position when the sheet piece is stretched.

[0022] In operation, before punching, the sheet thickness of the electromagnetic steel sheet is measured in the sheet thickness measuring unit 2, and the measured value is input to the pilot pin position control unit 10. The pilot pin position control unit 10 determines the target position of the pilot pin by referring to the relationship between the sheet thickness and the position of the pilot hole (relative to the planned punching position) that was previously determined. Then, control commands are sent to the actuators of the pilot pin displacement mechanisms 8, and the positions of the pilot pins are adjusted so that the actual positions of the pilot pins coincide with the target positions. After measuring the sheet thickness, the sheet is transported to the pilot hole drilling unit 3, where pilot holes are drilled. The sheet is then transported between the die plate and the punch plate, where the pilot pins are inserted into the pilot holes. During this process, the position of the sheet in the plane direction is adjusted while the pilot holes are aligned with the positions of the pilot pins. When the sheet is pressed, the planned punching position coincides with the position of the punching die, thereby achieving high dimensional accuracy at the planned punching position.

[0023] The above description has been made in relation to the embodiments of the present invention, but it will be apparent that many modifications and changes will be readily apparent to those skilled in the art, and the present invention is not limited to the above-described exemplary embodiments, but can be applied to various devices without departing from the concept of the present invention.

Claims

[Claim 1] A punching processing device for punching out a core sheet to be laminated to form a motor core from a sheet piece of electromagnetic steel sheet transported between a punch plate and a die plate, a thickness measuring means for measuring the thickness of the sheet piece before punching; a punching means for punching pilot holes in the sheet piece; a pilot pin target position determining means configured to determine target positions of pilot pins to be inserted into the pilot holes relative to positions of punching dies of a predetermined pattern on the punch plate and the die plate based on the measured plate thickness; a pilot pin position adjusting means for adjusting the position of the pilot pin so that it coincides with a target position of the pilot pin; Including, The pilot pin target position determination means is configured to determine the target position of the pilot pin so that the distance between the position of the pilot hole, which changes depending on the plate thickness, and the position at which the sheet piece is to be perforated or punched by the punching die coincides with the distance between the position of the punching die and the position of the pilot pin.

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