JP2004209785A - Extension drive device for stretching rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify and miniaturize an extension drive device for a stretching rod provided in a stretching blow device by employing a magnetic screw shaft and a magnetic nut member both of which can smoothly perform rotary-linear motion conversion in a non-contact state. <P>SOLUTION: In the extension drive device wherein the stretching rod is inserted into the blow core member of a vertically provided stretching blow device and the extension of the stretching rod is performed by converting the rotary motion due to an electromotive servo motor to linear motion by a screw shaft and a nut member, the screw shaft and the nut member are constituted of a magnetic screw shaft and a magnetic nut member. The extension drive device comprises a cylinder, the cylindrical plunger provided in the cylinder so as to advance and retreat freely and integrally having the magnetic nut member, the magnetic screw shaft inserted in the plunger through the magnetic nut member to be supported and the electromotive servo motor. The cylinder is connected to the installed disc provided at the upper part of the stretching blow device and the plunger is connected to the stretching rod attaching plate on the underside of the installed disc. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretching rod extension driving device that converts a rotary motion by an electric motor into a linear motion to extend a stretching rod.
[0002]
[Prior art]
Conventionally, a mechanism that converts the rotation of an extension rod for extending a preform into a linear motion by a ball screw and a ball nut by using a ball screw and a ball nut has been adopted (for example, see Patent Document 1).
In addition, there is a device that uses a magnetic screw as a moving unit of a transfer device (for example, see Patent Document 2).
[0003]
[Patent Document 1]
JP-A-2000-43131 (page 3, FIG. 1-2).
[Patent Document 2]
Japanese Patent No. 2685723 (page 1, FIG. 1-3).
[0004]
[Problems to be solved by the invention]
In the rotation-linear motion converting means using a ball screw shaft and a ball nut member which has been conventionally used, a ball circulation path is provided on the ball nut member side to smoothly move the screw shaft and the nut member relative to each other in the axial direction. I can do it. Therefore, a circulation path is formed in the ball nut member so as to protrude in the axial direction, which makes it difficult to simplify and reduce the size of the ball nut member.
[0005]
In addition, each time the stretching rod is extended or retracted, the ball in the thread groove receives a stress correspondingly either before or after the thread groove, so that if the stretching operation is repeatedly performed for a long time, the ball may generate a compressive stress. In many cases, fatigue failure occurs due to the friction, and there are problems such as requiring lubrication in order to prevent heat generation due to friction and requiring troublesome maintenance management.
[0006]
Furthermore, when the bottom mold is lifted into the cavity and the bottom of the preform is clamped by the stretching rod to complete the product, if the bottom mold collides with the tip of the stretching rod, the impact force is applied to the ball screw. Since this causes a failure, there is also a problem that it is necessary to synchronize the extension of the extension rod and the raising operation of the bottom mold so that such a situation does not occur.
[0007]
SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the problem in the case of the above-mentioned conventional ball screw shaft and ball nut member, and an object thereof is to provide a magnetic device capable of smoothly performing rotation-linear motion conversion in a non-contact state. An object of the present invention is to provide an extension drive device for an extension rod, which can be simplified and downsized by adopting a screw shaft and a magnetic nut member, and can be easily maintained.
[0008]
[Means for Solving the Problems]
According to the present invention with the above object, an extension rod is inserted into a blow core member of a standing extension blow device, and the extension of the extension rod is performed by converting a rotary motion by an electric servomotor into a linear motion by a screw shaft and a nut member. An extension drive device, wherein the screw shaft and the nut member include a magnetic screw shaft and a magnetic nut member.
[0009]
In addition, the extension driving device for an extension rod of the present invention is provided with a cylinder, a plunger of a cylindrical body integrally provided with the magnetic nut member, which is provided to be able to advance and retreat within the cylinder, and inserted and supported in the plunger through the magnetic nut member. The magnetic screw shaft and the electric servomotor on the cylinder side that rotates the magnetic screw shaft. The cylinder is connected to an installation board on an upper portion of a stretching blow device, and the plunger is connected to an extension rod below the installation board. It is connected to the mounting plate.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
In the drawing, reference numeral 1 denotes a fixed plate of a stretch blow apparatus which is erected on a vertically movable base 2 above the machine base, and is straddled over the tops of four columns 3, 3 erected on the upper surface of the base 2 in pairs. A pair of pneumatically or hydraulically operated lifting and lowering cylinders 4 and 4 are vertically mounted between the columns on both sides of the fixed platen 1. Reference numeral 5 denotes an installation board of the extension driving device 6, and both ends are connected to the piston rods 4a, 4a of the lifting cylinders 4, 4 and are provided below the fixed board 1 so as to be able to move up and down.
[0011]
Reference numeral 7 denotes a core holding plate, which has four corners inserted into the columns 3 and 3, and both sides are connected to the installation board 5 by tie rods 8 and 8 so as to move up and down together with the installation board 5. On the lower surface of the core holding plate 7, the same number of blow core members 9, 9 as the plurality of cavities 31, 31 of the blow mold 30 provided below the base 2 are provided on a seat plate 7a having an air passage. And is attached downward at every cavity interval.
[0012]
Reference numeral 10 denotes a mounting plate for the extension rod 11, which is provided between the installation board 5 and the core holding plate 7 with both ends inserted through the tie rods 8 and 8, and provided on the lower surface of each of the blow core members 9 and 9, respectively. The inserted extension rods 11, 11 are attached downward with their base end portions sandwiched between connecting plates 10a. A plunger 61, which will be described later, is connected to the center of the upper surface.
[0013]
The extension drive device 6 is provided with a cylinder 63 vertically installed with a connecting plate 62 at the center of the upper surface of the installation board 5 and a bush 64 fitted in the lower end of the cylinder 63. The cylindrical plunger 61 connected to the mounting plate 10 with the connecting plate 61a, a magnetic nut member 65 integrally fitted around the inner periphery of the upper part of the plunger 61, and a magnetic nut member 65 from the upper end of the cylinder through the plunger. And the lower shaft end 66a is connected to a magnetic screw shaft 66 supported by the plunger 61 with a bearing 65 and a pedestal 67 mounted on the upper end of the cylinder, and the upper shaft end of the magnetic screw shaft 66 supported by the bearing member 68 An electric servomotor 69 having a drive shaft 69a jointed to the motor 66b. Reference numeral 61b denotes a bush for preventing vibration, which is fixed between the cylinder 63 and the plunger 61 by a ring.
[0014]
The magnetic nut member 65 and the magnetic screw shaft 66 have the same N-pole magnetized band and S-pole magnetized band on the outer peripheral surface of the shaft made of permanent magnet material and the inner peripheral surface of the cylindrical body made of permanent magnet material. The magnetic nut member 65, which is formed in a spiral shape alternately at a pitch, is provided with a required clearance (for example, 0.5 mm) around the magnetic screw shaft 65 and is repelled and supported by the same pole counterpart, The magnetized band that rotates with the screw shaft 66 causes the same rotation. However, since the magnetic nut member 65 is integrated with the plunger 61 whose rotation has been prevented by the connection with the mounting plate 10, the magnetic nut member 65 moves linearly along the magnetic screw shaft 66 together with the plunger 61 without rotating. I do. When the magnetic screw shaft 66 stops, the magnetic nut member 65 is restrained by the magnetic screw shaft 66 by the magnetic force, and the plunger 61 is held at the stop position.
[0015]
In the stretching blow device provided with such an extension drive device 6, as shown in FIG. 1, the preform 34 held by the neck mold 33 is transferred by the transfer plate 32 provided on the lower surface of the base 2 to the mold. When positioned at the center of the opened blow mold 30, the entire apparatus descends together with the base 2, and the blow mold 30 and the neck mold 33 are closed.
[0016]
When the elevating cylinder 4 is actuated as shown in FIG. 2 after the mold is closed, the piston rod 4a connected to the installation board 5 is extended, and the core holding plate 7 connected to the installation board 5 and the tie rod 8 is lowered. As a result, the blow core member 9 fits tightly with the neck mold 33. At the same time, the rod mounting plate 10, which is restrained by the magnetic nut member 65 and the magnetic screw shaft 66, is hung by the extension driving device 6, and has been fixed at the upper position, is also lowered by the extension driving device 6 descending together with the installation board 5. Moving. As a result, the distal end of the elongated rod 11 projecting from the blow core member 9 is inserted into the preform 34 through the neck mold 33 until the distal end reaches the inner bottom surface of the preform.
[0017]
When the fitting and insertion of the blow core member 9 and the extension rod 11 are completed, the electric servomotor 69 that has applied the torque corresponding to the load of the mounting plate 10 to the magnetic screw shaft 66 operates, and the magnetic screw shaft 66 is moved. Rotate forward. As a result, the plunger 61, which is integrally stopped from rotating with the magnetic nut member 65, moves linearly downward and pushes down the mounting plate 10, and the extension rod 11 extends the preform 34 to the bottom mold setting.
At the same time, blow air is pressure-fed from an air circuit (not shown) to the blow core member 9, and the preform 34 expands from above to below, and then the bottom mold 35 is pushed up into the cavity, and the bottle having the same shape as the cavity is formed. 36 is stretch blow-molded (see FIG. 3).
[0018]
When the bottle molding is completed, the blow mold 30 is opened and the entire apparatus is moved upward by the base 2. In the movement process, the piston rod 4 a is pulled back by the operation of the elevating cylinder 4, and the magnetic force generated by the electric servomotor 69. The plunger 61 is moved upward by the reverse rotation operation of the screw shaft 66, and returns to the original upper position of the installation board 5, the core holding plate 7, and the rod mounting plate 10.
[0019]
In the illustrated embodiment, the electric servomotor 69 is attached to the upper end of the cylinder 63 and is directly connected to the magnetic screw shaft. However, the electric servomotor 69 is rotated by a transmission member such as a toothed pulley and a timing belt. May be transmitted to the magnetic screw shaft side, and may be arranged in parallel with the cylinder 63.
[0020]
As described above, the rotary motion of the magnetic screw shaft by the electric servomotor is converted into linear motion by the magnetic nut member to drive the stretching rod. Is unnecessary, and there is no protruding portion on the side of the magnetic nut member, so that the extension driving device can be simplified and can be handled as a single compact device, and the weight of the device can be reduced. Even if the position is the upper part of the stretching blow device, the installation work does not take much trouble, and the work can be performed safely.
[0021]
The nut member does not engage with the magnetic screw shaft like a ball screw, but is loosely fitted around the screw shaft while maintaining the set clearance. Since there is almost no error in the amount of movement of the magnetic screw member, the extension stop position of the extension rod can be reliably performed as set, and fatigue failure due to the compressive stress seen in the ball screw does not occur, so even during long-term use The function is sufficiently maintained, and maintenance and management become easy.
[0022]
Furthermore, in the magnetic screw shaft and the magnetic nut member, when an impact force greater than the torque applied to the magnetic screw shaft is received in the axial direction, the magnetic screw shaft rotates according to the impact force and absorbs the shock. Therefore, even when the bottom mold is raised into the cavity and the bottom of the preform is clamped by the stretching rod and molding is performed, complicated servo control that synchronizes the operation of the stretching rod and the bottom mold, which is indispensable for a ball screw, is required. It becomes unnecessary. Therefore, the control means can be simplified.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional front view of a main part of a stretching blow device provided with an extension driving device according to the present invention.
FIG. 2 is a half vertical sectional front view when the same mold is closed.
FIG. 3 is a vertical front view of a half part during stretch blow molding.
FIG. 4 is a side view at the time of stretch blow molding.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed board 2 Base 2 Support 4 Lifting cylinder 4a Piston rod 5 Installation board 6 Extension drive 7 Core holding plate 8 Tie rod 9 Blow core member 10 Extension rod mounting plate 11 Extension rod 30 Blow mold 34 Preform 61 Plunger 63 Cylinder 64 Spline bush 65 Magnetic nut member 66 Magnetic screw shaft 69 Electric servo motor

Claims (2)

An extension drive device that inserts an extension rod into a blow core member of an erect extension blow device and converts the rotation of the extension rod into a linear motion by a screw shaft and a nut member by a rotary shaft by an electric servomotor, An extension driving device for an extension rod, wherein the screw shaft and the nut member are constituted by a magnetic screw shaft and a magnetic nut member. A cylinder, a plunger having a cylindrical body integrally provided with the magnetic nut member and movable in the cylinder, the magnetic screw shaft inserted and supported in the plunger through the magnetic nut member, and rotating the magnetic screw shaft. And the electric servomotor on the cylinder side, wherein the cylinder is connected to an installation board on the upper part of the stretching blow device, and the plunger is connected to a mounting plate of a stretching rod below the installation board. The extension drive device for an extension rod according to claim 1.

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