JP3662142B2 - Ejector device backward limit position detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a backward limit position detecting device for an ejector device.
[0002]
[Prior art]
Conventionally, in an injection molding machine, a resin product heated and melted in a heating cylinder is filled in a cavity space of a mold apparatus at a high pressure, cooled in the cavity space, and solidified to obtain a molded product. ing.
The mold apparatus includes a fixed mold and a movable mold. For example, the movable mold is advanced and retracted by a toggle mechanism, and the mold is closed, clamped, and opened by moving the fixed mold into and out of contact with the fixed mold. Can be done. Then, in mold opening, the mold clamping device is retracted with the molded product remaining in the movable mold, and then the ejector pin is advanced by the ejector device, the molded product is ejected, and the mold release is performed. It has come to be.
[0003]
The ejector motor 102 includes a stator 105 fixed to a motor frame 104, a coil 106 fixed to the stator 105, and a rotor 107 disposed close to the inside of the stator 105, and current is supplied to the coil 106. By supplying, the rotor 107 can be rotated. The motor frame 104 includes a front flange 104a, a rear flange 104b, a stator frame 104c, and a tie rod 138 that connects and tightens the front flange 104a and the rear flange 104b.
[0004]
A hollow output shaft 110 is fixed further inside the rotor 107, and both ends of the hollow output shaft 110 are rotatably supported by the motor frame 104 by bearings 111 and 112. The hollow output shaft 110 has a medium diameter portion 115 as a first portion disposed inside the rotor 107, and a large diameter as a second portion formed on the movable platen 11 side from the medium diameter portion 115. The ball nut 120 is fixed to the inside of the large-diameter portion 116. The small-diameter portion 117 is formed as a third portion formed on the toggle support 101 side from the medium-diameter portion 115.
[0005]
Further, a ball screw shaft 121 is disposed by screwing with the ball nut 120, a cross head 25 is fixed to the front end of the ball screw shaft 121 by a nut 123, and an ejector rod 27 is fixed to the cross head 25. . The cross head 25 is prevented from rotating by the guide bar 18.
[0006]
Therefore, by driving the ejector motor 102 and rotating the rotor 107, the ball nut 120 is rotated in the direction of the arrow F, and the ball nut 120 and the ball screw shaft 121 are used to convert the rotational motion into a linear motion. The head 25 can be moved back and forth in the direction of arrow A along the guide bar 18. As a result, the ejector rod 27 and an ejector pin (not shown) can be advanced and retracted in the same direction.
[0007]
For this purpose, the ejector pin is disposed with its front end facing the cavity space, and the rear end is fixed to the ejector plate. In addition, an ejector pin feeder is connected to the rear end of the ejector plate via an ejector rod. Then, when the ejector pin feeding device is operated and the ejector plate is advanced through the ejector rod, the ejector pin fixed to the ejector plate is advanced.
[0008]
By the way, in an electric injection molding machine, the ejector pin feeder is usually operated by an electric motor.
FIG. 1 is a cross-sectional view of an essential part of a conventional ejector device already disclosed by the present applicant (see Japanese Patent Laid-Open No. 9-164567).
[0009]
In the figure, reference numeral 11 denotes a movable platen, and a movable mold (not shown) is attached to the front end (right end in FIG. 1) of the movable platen 11. The movable platen 11 is moved back and forth along a tie bar provided between a fixed platen and a toggle support (not shown) by a toggle mechanism (not shown).
[0010]
Further, an ejector pin feeding device is disposed at the rear end (left end in FIG. 1) of the movable platen 11. In the ejector pin feeder, the front end of the guide bar 18 is fixed to the surface of the movable platen 11 facing the toggle support, and the ejector motor 102 is fixed to the rear end of the guide post 18 by the bolt 103.
[0011]
In this case, it is necessary to advance and retract the cross head 25 and the ejector rod 27 by a stroke S necessary for ejecting a molded product (not shown) by the ejector pin. For this reason, the movable platen 11 has a depth corresponding to the stroke S. The recess 11a is formed. Further, since the ball screw shaft 121 is moved forward and backward by the stroke S by rotating the ball nut 120, a hollow portion 110a having a length corresponding to the stroke S is formed inside the middle diameter portion 115. .
[0012]
In order to control the ejector motor 102, an encoder 131 as a rotational speed sensor is fixed to the rear end of the hollow output shaft 110 so that the rotational speed of the rotor 107 can be directly detected by the encoder 131. It has become. Therefore, the position of the crosshead 25 can be accurately detected. In addition, a proximity switch 135 is disposed on the movable platen 11 in order to detect the backward limit position of the cross head 25. The proximity switch 135 can be reset for each molding. Note that a limit switch can be used instead of the proximity switch 135.
[0013]
As described above, in the conventional ejector device already disclosed by the present applicant, the rotary motion generated by the ejector motor 102 is converted into a linear motion, and the ejector pin feeding device is directly driven. There is no need to use a timing belt.
Therefore, the durability of the ejector device can be improved.
[0014]
[Problems to be solved by the invention]
However, in the conventional ejector device, in order to detect the backward limit position of the crosshead, the proximity switch or the limit switch is fixed with a bolt, so when the ejector rod and the mold are connected to each other, When the backward limit position is changed, it is difficult to adjust the position of the proximity switch or the like.
The present invention solves the problems of the conventional ejector device, the mounting position of the backward limit position detecting device can be freely and easily adjusted, the ejector rod and the mold are connected, and the backward limit position is changed. It is an object to make it easy to cope with the problem.
[0015]
[Means for Solving the Problems]
Therefore, in the backward limit position detecting device for an ejector apparatus according to the present invention, in the ejector apparatus in which the ejector motor of the ejector apparatus of the injection molding machine is disposed on the drive axis so as to directly drive the crosshead. A sensor that converts the rotation of the head into a linear motion by a ball screw and a ball nut, advances and retracts a crosshead including an ejector rod by the linear motion, fixes a cam to the crosshead, and detects a backward limit position of the crosshead. The motor frame was fixed using a groove formed on a pleat provided on the outer surface of the frame.
The grooves formed in the pleats are formed on the opposing surfaces of the pair of pleats and are sized so that bolt heads or nuts can be inserted along the longitudinal direction of the pleats.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
2 is a front view of the ejector motor according to the embodiment of the present invention, FIG. 3 is a schematic view of the ejector device including the ejector motor of FIG. 2, and FIG. 4 is a reverse view of the ejector device according to the embodiment of the present invention. FIG. 5 is a cross-sectional view taken along line VV in FIG. 4.
[0017]
In the figure, reference numeral 11 denotes a movable platen, and a movable mold (not shown) is attached to the front end (right end in FIG. 3) of the movable platen 11. The movable platen 11 is advanced and retracted by a toggle mechanism 14 along a tie bar provided between a fixed platen and a toggle support (not shown).
[0018]
An ejector pin feeder 16 is disposed at the rear end (left end in FIG. 3) of the movable platen 11. In the ejector pin feeding device 16, the front end of the guide bar 18 is fixed to the surface of the movable platen 11 facing the toggle support (not shown), and the ejector motor 102 is fixed to the rear end of the guide bar 18 by the bolt 103. .
[0019]
In the description of the ejector motor 102, the structure of the motor itself and the conventional ejector motor 102 is substantially the same, and will be described with the same reference numerals. See also FIG. The ejector motor 102 includes a stator 105 fixed to a motor frame 104, a coil 106 fixed to the stator 105, and a rotor 107 disposed close to the inside of the stator 105, and current is supplied to the coil 106. The rotor 107 can be rotated by being supplied (the internal structure of the ejector motor 102 is substantially the same as that of the conventional ejector motor 102, so see also FIG. 1). The motor frame 104 includes a front flange 104a, a rear flange 104b, a stator frame 104c, and a tie rod 138 that connects and tightens the front flange 104a and the rear flange 104b.
[0020]
A hollow output shaft 110 is fixed further inside the rotor 107, and both ends of the hollow output shaft 110 are rotatably supported by the motor frame 104 by bearings 111 and 112. The hollow output shaft 110 has a medium diameter portion 115 as a first portion disposed inside the rotor 107, and a large diameter as a second portion formed on the movable platen 11 side from the medium diameter portion 115. Part 116 and a small diameter part 117 as a third part formed on the toggle support 101 side from the medium diameter part 115, and the ball nut 120 is fixed inside the large diameter part 116 (these hollow output shafts). 110 and the structure of the ball nut 120 are substantially the same as the ejector motor 102 of the prior art, so refer to FIG.
[0021]
Further, a ball screw shaft 121 is disposed by screwing with the ball nut 120, a cross head 25 is fixed to the front end of the ball screw shaft 121 by a nut 123, and an ejector rod 27 is fixed to the cross head 25. . The cross head 25 is prevented from rotating by the guide bar 18.
[0022]
Accordingly, by driving the ejector motor 102 and rotating the rotor 107, the ball nut 120 is rotated, the ball nut 120 and the ball screw shaft 121 are used to convert the rotational motion into a linear motion, and the cross head 25 is guided. It can be advanced and retracted along the bar 18 in the direction of arrow A. As a result, the ejector rod 27 and an ejector pin (not shown) can be advanced and retracted in the same direction.
[0023]
As described above, in the present embodiment, the rotary motion generated by the ejector motor 102 disposed on the drive axis of the ejector device is converted into a linear motion, and the ejector pin feeder 16 is directly driven. Therefore, it is not necessary to use a timing belt.
[0024]
Further, in the motor frame 104, the stator frame 104c is made of aluminum, and a plurality of pleats 104d are provided on the outer surface in order to increase the heat dissipation surface area, thereby enhancing the heat dissipation effect.
[0025]
A bracket fixing groove 104f into which the head of the bolt 30 or the nut 31 can be inserted is provided on the opposing surface 104e of the pair of pleats 104d formed adjacent to each other and provided on the outer surface of the stator frame 104c. Then, the sensor 32 is fixed and the backward limit position of the cross head 25 is detected.
[0026]
That is, as shown in FIGS. 4 to 6, a sensor fixing bracket 33 having a substantially “Z” cross section is attached to the bracket fixing groove 104 f with the head or nut 31 of the bolt 30, and the bracket 33 is attached to the bracket 33 with the bolt 34. A reverse limit position detection sensor 32 is provided, and a rectangular plate-shaped cam 35 is fixed to the cross head 25 with a bolt 36 on the cross head 25, so that the sensor 32 detects the cam 35 and the cross head 25 moves backward. The limit position can be detected. The sensor 32 is preferably a proximity switch, but a limit switch can also be used.
[0027]
Then, with the bolt 30 and the nut 31 attached to the bracket 33, the head of the bolt 30 is inserted from one end side of the groove 104f. The mounting position of the bracket 33 can be freely adjusted according to the amount of insertion. In the embodiment of FIG. 5, the head of the bolt 30 is inserted into the groove 104f, but a nut 31 may be inserted.
[0028]
In order to control the ejector motor 102, an encoder 131 as a rotational speed sensor is fixed to the rear end of the hollow output shaft 110 so that the rotational speed of the rotor 107 can be directly detected by the encoder 131. It has become. Therefore, the position of the crosshead 25 can be accurately detected.
[0029]
Therefore, the backward limit position detection signal detected by the sensor 32 enables the origin of the encoder to be reset for each molding when the encoder 131 uses an incremental encoder having no absolute value. It is also used as an ejector return confirmation signal.
[0030]
【The invention's effect】
As described above, in the ejector apparatus in which the ejector motor of the ejector apparatus of the injection molding machine is arranged on the drive axis and the cross head is directly driven, the rotation of the ejector motor is linearly performed by the ball screw and the ball nut. A sensor for detecting the position of the retreating end of the crosshead is provided on the outer surface of the frame of the motor. Since it is fixed using a groove formed in the pleats, the mounting position of the sensor that detects the retreat limit position can be adjusted freely and easily, so the ejector rod and mold are connected to change the retreat limit position of the crosshead. Even in this case, it is possible to easily cope with the adjustment of the backward limit position detecting device.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a conventional ejector apparatus.
FIG. 2 is a front view of an ejector motor according to an embodiment of the present invention.
FIG. 3 is a schematic view of an ejector device including the ejector motor of FIG. 2;
FIG. 4 is a front view of a backward limit position detection device for an ejector device according to an embodiment of the present invention.
5 is an enlarged cross-sectional view taken along the line V-V in FIG. 4;
6 is an enlarged view of the vicinity of a pleat groove provided on the outer surface of the motor frame of FIG. 5;
[Explanation of symbols]
25 Crosshead 27 Ejector rod 30 Bolt 31 Nut 32 Sensor 33 Bracket 35 Cam
102 Ejector motor 104 Motor frame
104a Front flange 104b Rear flange
104c Stator frame 104d folds
104e Opposing surface 104f Bracket fixing groove
121 Ball screw shaft

Claims (2)

In an ejector apparatus in which an ejector motor of an ejector apparatus of an injection molding machine is disposed on a drive axis and the crosshead is directly driven, the rotation of the ejector motor is converted into a linear motion by a ball screw and a ball nut, A groove formed in a pleat provided on the outer surface of the frame of the motor is provided with a sensor for detecting the position of the crosshead retracting by moving a crosshead including an ejector rod forward and backward by linear motion, fixing a cam to the crosshead. A backward limit position detecting device for an ejector device characterized by being fixed by using. The grooves formed in the pleats are formed on opposing surfaces of the pair of pleats, and are formed in a size that allows insertion of bolt heads or nuts along the longitudinal direction of the pleats. Item 2. A backward limit position detecting device for an ejector device according to Item 1.

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