JP2004343843A - Dc linear motor and electric injection molding machine using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric injection molding machine comprising a DC linear motor capable of preventing a trouble caused by the sticking of foreign substances to coils. <P>SOLUTION: The electric injection molding machine uses a DC linear motor 52 as a drive source. The DC linear motor 52 comprises coils 70 for generating magnetic fields, magnets 72, and dustproof covers 120 and 121. The dustproof covers 120 and 121 are provided between the magnets 72 and support members 62 and 63. Outside the dustproof covers 120 and 121, a position detector 130 such as a linear scale for controlling the position of the DC linear motor 52 is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a DC linear motor and an electric injection molding machine using the same.
[0002]
[Prior art]
It has been considered to use a DC linear motor as a direct drive source for an injection operation of an electric injection molding machine, mold clamping, product extrusion, and the like. For example, a synchronous DC linear motor includes a coil unit that generates a magnetic field, a magnet unit that linearly moves along a guide member, and the like. By connecting this magnet part to the screw of the injection molding machine, the screw can be moved in the axial direction.
[0003]
[Problems to be solved by the invention]
Since the magnet part of the conventional DC linear motor is bare, any dust, especially conductive foreign matter such as metal dust, between the coil part and the magnet part may cause a short circuit accident in the coil part. Is concerned.
[0004]
It is conceivable to cover the entire linear motor with a cover in order to prevent foreign matter from adhering to the coil part.However, with an electric injection molding machine, a position detector such as a linear scale is required to control the position of the linear motor. It is. For this reason, if the entire linear motor is covered by the cover, the position detector is hidden inside the cover member, making it difficult to perform mounting work, wiring work, and maintenance of the position detector. Further, it becomes difficult to visually confirm the operation of the linear motor.
[0005]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a DC linear motor capable of preventing operation failure or the like due to foreign matter adhering to a coil portion, and an electric injection molding machine using the same.
[0006]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a DC linear motor and an electric injection molding machine, comprising: a coil for generating a magnetic field; a support member for supporting the coil; and a coil for supplying a current to the coil. A magnet unit that relatively moves in the axial direction; and a dustproof cover attached to the support member and the magnet unit to cover a gap between the support member and the magnet unit and that covers an outer peripheral side of the coil unit. are doing.
In a preferred aspect of the present invention, a position detector for detecting a relative position between the support member and the magnet unit is provided outside the dustproof cover.
[0007]
A DC linear motor and an electric injection molding machine according to the present invention based on a second aspect include a coil portion for generating a magnetic field, a support member for supporting an end of the coil portion, and a device for supplying a current to the coil portion. The apparatus includes a magnet unit that moves relatively in the axial direction of the coil unit, and a partition member that is provided between the coil unit and the magnet unit and that is made of an electrically insulating nonmagnetic material.
In a preferred embodiment of the present invention, the partition member has a cylindrical shape so as to cover the entire outer periphery of the coil portion.
[0008]
The present invention can be applied to an injection molding machine for synthetic resin products, or to an injection molding machine for elastic products such as rubber (including synthetic rubber including silicon rubber and natural rubber) or elastomer. You can also. Alternatively, the present invention can be applied to an injection molding machine for metal products such as aluminum die casting.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The electric injection molding machine 20 shown in FIG. 1 includes an injection device 21 located on the right side in FIG. 1 and a mold clamping device 22 located on the left side in FIG.
[0010]
The mold clamping device 22 includes a fixed platen 25, a movable platen 26, and a drive mechanism 28 (only a part of which is shown) for moving the movable platen 26 along the tie bar 27. A fixed mold 30 (shown in FIG. 2) is attached to the fixed platen 25, and a movable mold 31 (shown in FIG. 2) is attached to the movable platen 26.
[0011]
As shown in FIG. 2, the injection device 21 is provided on the fixed base 40. The injection device 21 has a main frame 42 that can reciprocate along a guide rail 41 provided on a fixed base 40, and is a front-rear direction of the electric injection molding machine 20 (an axial direction indicated by an arrow X in FIG. 2). You can move to.
[0012]
The injection device 21 includes a frame structure 50, a barrel 51, a voice coil type DC linear motor (direct current type linear motor) 52 functioning as a driving source for the injection operation, a screw rotating mechanism 53, and the like. A screw 54 is housed in the barrel 51. A drive unit 55 is constituted by the DC linear motor 52, the following sub-frame 60, the following linear guide mechanism 74, and the like.
[0013]
The sub-frame 60 is fixed on the main frame 42 by fixing parts 61 such as bolts. The sub-frame 60 includes a front support member (front stand) 62 and a rear support member (rear stand) 63. The lower portions of the support members 62 and 63 are connected to each other by a base member 64 extending in the horizontal direction.
[0014]
The frame structure 50 includes a first portion 65 that supports the base of the barrel 51, a second portion 66 that is coupled to the DC linear motor 52 side, and each of the first portion 65 and the second portion 66. And a bottom wall 69 and the like.
[0015]
The voice coil type DC linear motor 52 includes a fixed side member 71 including a plurality of coil sections 70 and a movable side member 73 including a plurality of magnet sections 72 driven in the X direction by a magnetic field generated by the coil section 70. And so on.
[0016]
The fixed-side member 71 includes the sub-frame 60, the coil unit 70, and the like. The support members 62 and 63 are fixed to the main frame 42, and, for example, four coil portions 70 are provided between the support members 62 and 63 in parallel with each other.
[0017]
The movable member 73 reciprocates between the support members 62 and 63 by a linear guide mechanism 74 provided on the base member 64. The linear guide mechanism 74 includes a rail 80 provided on the base member 64, a plurality of sets of carriages 81 sliding along the rail 80, and the like. The carriage 81 is attached to the lower surface of the support plate 78.
[0018]
The movable side member 73 includes connecting plates 75 and 76 provided on both front and rear sides of the magnet section 72, a spacer 77 made of a non-magnetic material provided between the front and rear magnet sections 72, and a support plate 78 extending in the horizontal direction. Contains. The magnet portion 72, the connection plates 75 and 76, and the spacer 77 are fastened to each other by a connection rod 79 (shown in FIG. 4 and the like).
[0019]
The output shaft 85 of the DC linear motor 52 is provided on the front connection plate 75. The output shaft 85 is connected to the screw 54 via a shaft 90 described later.
[0020]
Each coil portion 70 of the DC linear motor 52 is formed in a cylindrical shape by winding a conducting wire 70a as schematically shown in FIG. 5, and an iron core (yoke 87) is provided inside the coil portion 70. I have. A magnet section 72 is provided on the outer peripheral side of the coil section 70. The movable-side member 73 including the magnet unit 72 relatively moves in the direction of the axis C (shown in FIG. 5) of the coil unit 70 based on a magnetic field generated when an electric current is supplied to the coil unit 70.
[0021]
The coil unit 70 is connected to a current supply device 70c via a power cable 70b. To prevent disconnection of the power cable 70b, it is desirable that the coil section 70 be on the fixed side and the magnet section 72 be on the movable side as in this embodiment. If measures are taken to allow the power cable 70b to move without difficulty, the coil section 70 and the yoke 87 may be on the moving side, and the magnet section 72 may be on the fixed side.
[0022]
Note that a magnet unit may be provided inside the coil unit 70 and a yoke may be provided outside the coil unit 70. Further, the coil unit 70 may be a rectangular tube. The shape and the like of the magnet portion 72 are also arbitrary, and a shape having an appropriate shape may be used as needed.
[0023]
In the vicinity of the base of the barrel 51, a hopper 88 for supplying a resin that is a material of an injection molded product is provided. The hopper 88 is attached to the first portion 65 of the frame structure 50. The barrel 51 is provided with a heater (not shown) for heating and melting the resin.
[0024]
The screw rotation mechanism 53 includes a shaft 90 to which the screw 54 is connected, a sleeve member 91 fitted to the shaft 90, a motor 92 for rotating the sleeve member 91, a first bearing 93, The bearing unit 94 is included.
[0025]
More specifically, as schematically shown in FIG. 3, a spline portion 95 is formed on the outer periphery of the shaft 90 along the axial direction. By fitting the sleeve member 91 to the spline portion 95, the shaft 90 can be moved relative to the sleeve member 91 in the axial direction, and the shaft 90 and the sleeve member 91 can be integrally rotated. It has become.
[0026]
The sleeve member 91 is rotatably supported on the intermediate support wall 100 by the first bearing portion 93. The intermediate support wall 100 is fixed to the bottom wall 69 of the frame structure 50.
[0027]
A motor support 101 is provided above the frame structure 50, and the motor 92 is mounted on the motor support 101. A power transmission member 105 such as a belt is wound between a driving pulley 103 attached to the output shaft 102 of the motor 92 and a driven pulley 104 attached to the sleeve member 91.
[0028]
Therefore, by rotating the output shaft 102 of the motor 92, the sleeve member 91 can be rotated. When the sleeve member 91 rotates, the shaft 90 fitted to the spline portion 95 rotates, so that the screw 54 rotates.
[0029]
The rear end of the shaft 90 is connected to the output shaft 85 of the DC linear motor 52 by a connection mechanism 106 having a second bearing 94. The connection mechanism 106 connects the output shaft 85 and the shaft 90 to each other, and allows relative movement of the two in the rotation direction. That is, the linear motion of the output shaft 85 in the axial direction can be transmitted to the shaft 90, and the rotational motion of the shaft 90 is not transmitted to the output shaft 85.
[0030]
The nozzle 110 formed at the tip of the barrel 51 is located on the center line of the hole 111 formed in the fixed platen 25. The fixed platen 25 and the frame structure 50 are connected to each other by, for example, a ball screw 115 and a nozzle touch mechanism 116 using a servomotor or the like.
[0031]
By driving the nozzle touch mechanism 116, the injection device 21 can be moved forward and backward with respect to the fixed platen 25 along the guide rail 41. With the injection device 21 advanced to a predetermined position, the tip of the nozzle 110 contacts the injection port 30 a of the fixed mold 30.
[0032]
The DC linear motor 52 of this embodiment includes dustproof covers 120 and 121. The front dust cover 120 is attached to the front support member 62 and the magnet 72 so as to close the gap between the front support 62 and the magnet 72. The rear dustproof cover 121 is attached to the rear support member 63 and the magnet unit 72 so as to close a gap between the rear support member 63 and the magnet unit 72.
[0033]
The part of the outer periphery of the coil section 70 that is exposed outside the magnet section 72 is covered with dustproof covers 120 and 121. The dustproof covers 120 and 121 prevent foreign matter such as dust, metal powder, and liquid from adhering to the outer surface of the coil unit 70.
[0034]
The dustproof covers 120 and 121 are made of a soft material such as rubber, a polymer material, or a cloth that is hard to generate dust, and are formed in a shape that goes around the coil portion 70 continuously in the circumferential direction. For example, by being formed in a bellows (bellows), a diaphragm, or a bag shape, it can be deformed flexibly following the moving direction of the magnet unit 72.
[0035]
In order to control the position of the DC linear motor 52, a position detector 130 such as a linear scale is provided on the DC linear motor 52. As an example, the scale main body 130 a of the position detector 130 is attached to the support member 63, and the scale head 130 b as a part to be detected is attached to the magnet part 72.
[0036]
The relative position between the coil unit 70 and the magnet unit 72 is detected by the position detector 130, and the detection signal is fed back to the controller 131 (schematically shown in FIG. 3).
[0037]
In this embodiment, the gap between the support members 62 and 63 and the magnet part 72 is covered by dustproof covers 120 and 121, and the position detector 130 is arranged outside the dustproof covers 120 and 121. For this reason, even if the dustproof covers 120 and 121 are provided, the mounting work, the wiring work, and the maintenance of the position detector 130 can be easily performed. Further, when the DC linear motor 52 operates, the movement of the magnet unit 72 can be visually confirmed.
[0038]
Next, the operation of the electric injection molding machine 20 having the above configuration will be described.
The dies 30 and 31 are closed by the mold clamping device 22, and the injection device 21 is advanced toward the fixed platen 25 by the nozzle touch mechanism 116 so that the tip of the nozzle 110 abuts the injection port 30 a of the fixed mold 30. Let it.
[0039]
Then, by supplying a current to the coil portion 70 of the DC linear motor 52, the movable member 73 of the DC linear motor 52 is moved forward as schematically shown in FIG. The position of the magnet unit 72 with respect to the coil unit 70 is detected by the position detector 130 and fed back to the controller 131, whereby the position of the DC linear motor 52 is controlled.
[0040]
When the movable side member 73 moves forward by the DC linear motor 52, the shaft 90 moves forward via the output shaft 85, and further the screw 54 moves forward, so that the material previously measured in the barrel 51 is dispensed by the screw 54 into the nozzle 110 And the molds 30 and 31 are filled.
[0041]
Next, the screw 54 is rotated by rotating the shaft 90 by the screw rotation motor 92. Accordingly, the material is kneaded while being sent to the tip end side of the barrel 51, and the material is measured. After the material injected into the molds 30 and 31 is cooled, the molds 30 and 31 are opened, and the molded product is ejected by the ejector mechanism, thereby completing one cycle of the injection molding process.
[0042]
6 and 7 show a second embodiment of the present invention. In the DC linear motor 52 'of this embodiment, the entire outer peripheral surface of the coil unit 70 is covered by a cylindrical partition member 140 made of a non-magnetic material. The partition member 140 is desirably made of a material having electrical insulation and low dust generation, such as a polyfluoroethylene resin.
[0043]
The partition member 140 prevents foreign substances such as dust, metal powder, and liquid from adhering to the coil section 70. Note that there may be no gap S between the outer peripheral surface of the coil unit 70 and the inner peripheral surface of the partition member 140.
[0044]
In the second embodiment, since the configuration other than the partition member 140 is the same as that of the electric injection molding machine 20 of the first embodiment, the same parts as those of the first embodiment are denoted by the same reference numerals. Is omitted. In the second embodiment, since the coil portion 70 is covered by the partition member 140, the dustproof covers 120 and 121 of the first embodiment do not need to be used. However, in order to further enhance the dustproof effect, the dustproof cover 120 is used. , 121 and the partition member 140 may be used together.
[0045]
In carrying out the present invention, the components of the present invention such as the coil unit and the magnet unit, the support member, the dust-proof cover, and the partition member can be variously modified without departing from the gist of the present invention. Needless to say. INDUSTRIAL APPLICABILITY The DC linear motor according to the present invention can be used as a drive source that performs a linear reciprocating motion (linear motion drive) such as a mold clamping device or an ejector mechanism for product extrusion in addition to an injection operation for moving a screw in an axial direction. .
[0046]
【The invention's effect】
According to the present invention, by covering the gap between the coil unit and the magnet unit with the dustproof cover, it is possible to prevent foreign matter such as dust from adhering to the coil unit, and to operate the DC linear motor satisfactorily. . If a position detector such as a linear scale is arranged outside the dust-proof cover, the work of mounting the position detector, wiring work or maintenance can be easily performed.
[0047]
Further, by covering the outer periphery of the coil portion with a partition member made of an electrically insulating non-magnetic material, it is possible to prevent a short circuit accident of the coil portion due to adhesion of foreign matter.
[Brief description of the drawings]
FIG. 1 is a perspective view of an electric injection molding machine showing one embodiment of the present invention.
FIG. 2 is a sectional view taken along the axial direction of a part of the injection molding machine shown in FIG.
FIG. 3 is a cross-sectional view schematically showing a state in which a screw of the injection molding machine shown in FIG. 1 has advanced.
FIG. 4 is a perspective view of a DC linear motor of the injection molding machine shown in FIG.
FIG. 5 is a perspective view schematically showing a part of the DC linear motor shown in FIG. 4;
FIG. 6 is a cross-sectional view of a DC linear motor showing another embodiment of the present invention.
FIG. 7 is a sectional view taken along line F7-F7 in FIG. 6;
[Explanation of symbols]
20 electric injection molding machine 52, 52 'DC linear motor 62, 63 support member 70 coil part 72 magnet part 120, 121 dustproof cover 130 position detector 140 partition member

Claims (6)

A coil unit for generating a magnetic field,
A support member for supporting the coil portion;
A magnet unit that relatively moves in the axial direction of the coil unit when a current is supplied to the coil unit;
A dustproof cover attached to the support member and the magnet unit to cover a gap between the support member and the magnet unit, and covering an outside of the coil unit;
A DC linear motor comprising: In an electric injection molding machine using a DC linear motor as a linear drive source,
The DC linear motor,
A coil unit for generating a magnetic field,
A support member for supporting an end of the coil portion;
A magnet unit that relatively moves in the axial direction of the coil unit when a current is supplied to the coil unit;
A dustproof cover attached to the support member and the magnet unit to cover a gap between the support member and the magnet unit, and covering an outside of the coil unit;
An electric injection molding machine comprising: The electric injection molding machine according to claim 2, wherein a position detector that detects a relative position between the coil unit and the magnet unit is provided outside the dustproof cover. A coil unit for generating a magnetic field,
A support member for supporting an end of the coil portion;
A magnet unit that relatively moves in the axial direction of the coil unit when a current is supplied to the coil unit;
A partition member made of an electrically insulating non-magnetic material provided between the coil portion and the magnet portion,
A DC linear motor comprising: The DC linear motor according to claim 4, wherein the partition member has a cylindrical shape that covers the entire outer periphery of the coil portion. In an electric injection molding machine using a DC linear motor as a linear drive source,
The DC linear motor,
A coil unit for generating a magnetic field,
A support member for supporting an end of the coil portion;
A magnet unit that relatively moves in the axial direction of the coil unit when a current is supplied to the coil unit;
A partition member made of an electrically insulating non-magnetic material provided between the coil portion and the magnet portion,
An electric injection molding machine comprising:

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