JP2000309039A - Retreat limit location detecting device for ejector device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the location adjustment of a sensor by making an ejector rod retreat through a ball screw mechanism by a rotating motion of a motor, and fixing the sensor for detecting the rear end limit location of the ejector rod to a pleated section on the outer periphery of the motor, in an ejector device which takes out a molded article from a die in an injection molding machine. SOLUTION: Power is turned on for an ejector motor 102, and by rotating the rotor, a ball nut fixed to the rotor is rotated, and a ball screw shaft 121 which is screwed with the ball nut is made to perform a linear motion, and a cross head 25 is advanced/retracted in the direction A along a guide bar 18. By this constitution, a molded article is taken out from a die through an ejector rod 27 which is fixed to the cross head 25, and an ejector pin. In this case, a bolt 30 is fixed between a pair of plates being adjacent, which are fins formed on the outer surface of a stator frame 104c, and a sensor 32 which detects the retreat limit location of the cross head 25 is location-adjustably fixed in the length direction of the pleats by using the bolt 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a backward limit position of an ejector device.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, a resin heated and melted in a heating cylinder is filled at a high pressure into a cavity space of a mold apparatus, and cooled and solidified in the cavity space. To get the goods. The mold apparatus is composed of a fixed mold and a movable mold.For example, by moving the movable mold forward and backward by a toggle mechanism, and moving the movable mold toward and away from the fixed mold, mold closing, mold closing and mold opening are performed. Can be done. And in the mold opening, the mold clamping device
The molded product is retracted while being left in the movable mold. Subsequently, an ejector pin is advanced by an ejector device, the molded product is protruded, and the mold is released.

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 arranged close to the inside of the coil 106. By supplying a current to the coil 106, the rotor 107 can be rotated. Further, the motor frame 104 has a front flange 1.
04a, rear flange 104b, stator frame 104
c, and the front flange 104a and the rear flange 104b
And a tie rod 138 for coupling and tightening.

A hollow output shaft 110 is fixed further inside the rotor 107, and both ends of the hollow output shaft 110 are supported by bearings 111 and 112 on the motor frame 1.
04 is rotatably supported. The hollow output shaft 1
Reference numeral 10 denotes a medium diameter portion 115 as a first portion disposed inside the rotor 107, and a large diameter portion 11 as a second portion formed on the movable platen 11 side from the medium diameter portion 115.
6 and a small diameter portion 117 as a third portion formed on the toggle support 101 side from the middle diameter portion 115, and a ball nut 120 is fixed inside the large diameter portion 116.

[0005] A ball screw shaft 121 is provided so as to be screwed with the ball nut 120.
The crosshead 25 is fixed to the front end by a nut 123, and the ejector rod 27 is fixed to the crosshead 25. Then, the cross head 25 is prevented from rotating by the guide bar 18.

Therefore, the ejector motor 102
To rotate the rotor 107, thereby rotating the ball nut 120 in the direction of arrow F. The ball nut 120 and the ball screw shaft 121 convert the rotational motion into a linear motion, and the crosshead 25
8 along the direction of arrow A. As a result, the ejector rod 27 and the ejector pin (not shown) can be moved in the same direction.

For this purpose, the ejector pins are disposed with the front end facing the cavity space, and the rear end is fixed to the ejector plate. An ejector pin feeder is connected to a rear end of the ejector plate via an ejector rod. Then, when the ejector pin feeder is operated and the ejector plate is advanced through the ejector rod, the ejector pin fixed to the ejector plate is advanced.

By the way, in an electric injection molding machine,
Usually, the ejector pin feeder is operated by an electric motor. FIG. 1 is a sectional view of a main part of a conventional ejector device already disclosed by the present applicant (see Japanese Patent Application Laid-Open No. 9-164567).

In FIG. 1, reference numeral 11 denotes a movable platen.
A movable mold (not shown) is attached to a front end (right end in FIG. 1) of the movable platen 11. The movable platen 1
1 is advanced and retracted by a toggle mechanism (not shown) along a tie bar provided between a fixed platen (not shown) and a toggle support (not shown).

The rear end of the movable platen 11 (FIG. 1)
(The left end) is provided with an ejector pin feeder. In the ejector pin feeder, a front end of a guide bar 18 is fixed to a surface of the movable platen 11 facing the toggle support, and an ejector motor 102 is fixed to a rear end of the guide post 18 by bolts 103.

In this case, it is necessary to advance and retreat the crosshead 25 and the ejector rod 27 by a stroke S necessary for projecting a molded product (not shown) by the ejector pin. A concave portion 11a having a desired depth is formed.
In addition, since the ball screw shaft 121 is advanced and retracted 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. .

In order to control the ejector motor 102, an encoder 131 as a rotation speed sensor is fixed to the rear end of the hollow output shaft 110, and the rotation speed of the rotor 107 can be directly detected by the encoder 131. I can do it. Therefore, the position of the crosshead 25 can be accurately detected. In addition, a proximity switch 135 is provided on the movable platen 11 to detect the retreat limit position of the crosshead 25. The proximity switch 135 can be reset each time molding is performed. The proximity switch 1
A limit switch can be used in place of 35.

As described above, in the conventional ejector apparatus disclosed by the present applicant, the ejector motor 102
Convert the rotational motion generated by the
Since the ejector pin feeder is directly driven, there is no need to use a timing belt. Therefore, the durability of the ejector device can be improved.

[0014]

However, in the above-described conventional ejector device, the proximity switch or the limit switch is fixed by bolts in order to detect the retreat limit position of the crosshead. It has been difficult to adjust the position of the proximity switch and the like when the retreat limit position changes when the rod and the mold are connected. The present invention solves the problems of the above-described conventional ejector device, and can freely and easily adjust the mounting position of the retreat limit position detection device, connect the ejector rod and the mold, and change the retreat limit position. It is an object of the present invention to be able to easily cope with the problem.

[0015]

Therefore, in the retreat limit position detecting device of the present invention, the ejector motor of the ejector device of the injection molding machine is disposed on the drive axis to directly drive the crosshead. In the ejector device, the rotation of the ejector motor is converted into a linear motion by a ball screw and a ball nut, and the linear motion causes the crosshead provided with the ejector rod to advance and retreat, and a cam is fixed to the crosshead. A sensor for detecting the retreat limit position was fixed using a groove formed in a pleat provided on the outer surface of the motor frame. The grooves formed in the pleats are formed on opposing surfaces of the pair of pleats, and are formed to have a size in which bolt heads or nuts can be inserted along the longitudinal direction of the pleats.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a front view of the ejector motor according to the embodiment of the present invention, FIG. 3 is a schematic diagram of an ejector device including the ejector motor of FIG. 2, and FIG. A front view (rear view of FIG. 3) of the limit position detecting device, and FIG. 5 is a sectional view taken along line VV of FIG.

In the figure, reference numeral 11 denotes a movable platen,
A movable mold (not shown) is attached to a front end (right end in FIG. 3) of the movable platen 11. The movable platen 1
1 is advanced and retracted by a toggle mechanism 14 along a tie bar provided between a fixed platen (not shown) and a toggle support.

The rear end of the movable platen 11 (FIG. 3)
(The left end in the figure), an ejector pin feeder 16 is provided. In the ejector pin feeder 16,
A front end of a guide bar 18 is fixed to a surface of the movable platen 11 facing a toggle support (not shown), and an ejector motor 102 is fixed to a rear end of the guide bar 18 by bolts 103.

In the description of the ejector motor 102, the structure of the motor itself and the structure of the conventional ejector motor 102 are substantially the same, and the same reference numerals are used. Also,
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 10 disposed close to the inside of the stator 105.
7 so that the rotor 107 can be rotated by supplying a current to the coil 106. (The internal structure of the ejector motor 102 is substantially the same as that of the conventional ejector motor 102. 1). In addition, the motor frame 104
Is a tie rod 1 for connecting and fastening the front flange 104a, the rear flange 104b, the stator frame 104c, and the front flange 104a and the rear flange 104b.
38.

Further, a hollow output shaft 110 is fixed further inside the rotor 107, and both ends of the hollow output shaft 110 are connected to the motor frame 1 by bearings 111 and 112.
04 is rotatably supported. The hollow output shaft 1
Reference numeral 10 denotes a medium diameter portion 115 as a first portion disposed inside the rotor 107, and a large diameter portion 11 as a second portion formed on the movable platen 11 side from the medium diameter portion 115.
6, and a small diameter portion 117 as a third portion formed on the toggle support 101 side from the middle diameter portion 115, and a ball nut 120 is fixed inside the large diameter portion 116 (these hollow output shafts 110). , Ball nut 12
0 is also substantially the same as the ejector motor 102 of the prior art, so also refer to FIG. 1).

A ball screw shaft 121 is screwed with the ball nut 120, and the ball screw shaft 121
The crosshead 25 is fixed to the front end by a nut 123, and the ejector rod 27 is fixed to the crosshead 25. Then, the cross head 25 is prevented from rotating by the guide bar 18.

Therefore, the ejector motor 102
To rotate the ball nut 120 by rotating the rotor 107 to rotate the ball nut 120.
The rotary motion is converted into a linear motion by the ball screw shaft 121 and the cross head 25 can be moved back and forth along the guide bar 18 in the direction of arrow A. As a result, the ejector rod 27 and the ejector pin (not shown) can be moved in the same direction.

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. This eliminates the need to use a timing belt.

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 to increase the heat radiation surface area, thereby enhancing the heat radiation effect.

A pair of pleats 10 formed on the outer surface of the stator frame 104c and formed adjacent to each other are provided.
4d facing surface 104e, the head of the bolt 30 or the nut 3
1 is provided with a bracket fixing groove 104f in which the sensor 32 can be inserted.
The retreat limit position is detected.

That is, as shown in FIGS. 4 to 6, the sensor fixing bracket 3 having a substantially "Z" cross section is inserted into the bracket fixing groove 104f with the head of the bolt 30 or the nut 31.
3 and a sensor 32 for detecting the retreat limit position with a bolt 34 on the bracket 33 and fixing a rectangular plate-like cam 35 to the crosshead 25 with a bolt 36 on the crosshead 25 so that the sensor 32 By detecting the cam 35, the retreat limit position of the cross head 25 can be detected. Although the sensor 32 is preferably a proximity switch, a limit switch may be used.

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 of the groove 104f. The mounting position of the bracket 33 can be freely adjusted depending on the insertion amount.
In the embodiment of FIG. 5, the head of the bolt 30 is inserted into the groove 104f, but the nut 31 may be inserted.

In order to control the ejector motor 102, an encoder 131 as a rotation speed sensor is fixed to the rear end of the hollow output shaft 110, and the rotation speed of the rotor 107 can be directly detected by the encoder 131. I can do it. Therefore, the position of the crosshead 25 can be accurately detected.

Therefore, the backward limit position detection signal detected by the sensor 32 is generated when the encoder 131 uses an incremental encoder having no absolute value.
It is used to make it possible to reset the origin of the encoder after each molding, and is also used as an ejector return confirmation signal.

[0030]

As described above, the ejector motor of the ejector device of the injection molding machine is disposed on the drive axis.
In an ejector device configured to directly drive the crosshead, the rotation of the ejector motor is converted into linear motion by a ball screw and a ball nut, and the linear motion causes the crosshead including the ejector rod to advance and retreat.
A cam was fixed to the crosshead, and a sensor for detecting the retreat limit position of the crosshead was fixed by using a groove formed in a pleat provided on the outer surface of the frame of the motor.
Since the mounting position of the sensor that detects the retreat limit position can be freely and easily adjusted, the ejector rod and the mold are connected,
Even if the retreat position of the crosshead changes,
Adjustment of the backward limit position detecting device can be easily performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a conventional ejector device.

FIG. 2 is a front view of an ejector motor according to the 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 the retreat limit position detecting device of the ejector device according to the embodiment of the present invention.

FIG. 5 is an enlarged sectional view taken along line VV in FIG. 4;

FIG. 6 is an enlarged view of the vicinity of a groove of a pleat 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 Fold 104e Opposite surface 104f Bracket fixing groove 121 Ball screw shaft

Claims (2)

[Claims] 1. An ejector device of an injection molding machine, wherein an ejector motor of an ejector device is disposed on a drive axis to directly drive a crosshead, wherein the rotation of the ejector motor is linearly moved by a ball screw and a ball nut. The linear motion causes a crosshead provided with an ejector rod to advance and retreat, a cam is fixed to the crosshead, and a sensor for detecting a retreat limit position of the crosshead is provided on an outer surface of a frame of the motor. A retreat limit position detecting device, wherein the ejector device is fixed using a groove formed in the ejector device. 2. A groove formed in the pleat is formed on an opposing surface of the pair of pleats, and is formed along a longitudinal direction of the pleat such that a bolt head or a nut can be inserted. The retractable position detecting device for an ejector device according to claim 1, wherein