JP2004299330A - Power transmission mechanism for electric injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a twisting phenomenon of a belt which is easily generated when power transmission is performed by a way how to wrap a timing belt by wrap the timing belt on a driving pulley of an electric motor and driven pulleys of a plurality of screw shafts. <P>SOLUTION: In a molding machine, a rotating power of the electric motor is transmitted to a plurality of the screw shafts, and the rotating power of the screw shafts is converted to a moving power of an injection plate by a nut member to inject a resin. When the power transmission is performed by the timing belt hung on the driving pulley of the electric motor side and the driven pulleys of the screw shaft side, the timing belt is individually wrapped on the driving pulley and on the driven pulleys. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power transmission mechanism of an injection molding machine using a drive source as an electric motor.
[0002]
[Prior art]
In a conventional electric injection molding machine, when a plurality of ball screw shafts are simultaneously driven by one electric motor, a timing belt is provided over a drive pulley of the electric motor and a driven pulley of both ball screw shafts to transmit power. ing. (For example, see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-176976 (page 3, FIG. 1).
[0004]
[Problems to be solved by the invention]
In the above-described related art, the timing belt is provided over the drive shaft and the plurality of driven pulleys, and thus the driven pulley is easily affected by the tension applied to the timing belt. Therefore, as the operating time elapses, the screw shaft is likely to be distorted, and there is a concern that the transmission mechanism may have a short life.
[0005]
The present invention has been conceived in order to solve the above-mentioned conventional problems, and has as its object to reduce the load on the screw shaft due to the tension of the timing belt by providing the timing belt on a plurality of driven pulleys. Another object of the present invention is to provide a new power transmission mechanism that can freely adjust the tension of the timing belt and contribute to downsizing of the entire mechanism.
[0006]
[Means for Solving the Problems]
The present invention according to the above object is directed to a molding machine that transmits a rotational force of one electric motor to a plurality of screw shafts, converts the rotational force of the screw shaft into a moving force of an injection plate by a nut member, and injects resin. When the power transmission is performed by the timing belt provided on the drive pulley on the electric motor side and the driven pulley on the screw shaft side, the timing belt is individually provided over the drive pulley and each driven pulley. It is.
[0007]
Further, the present invention relates to a molding machine that transmits a rotational force of a plurality of electric motors to a plurality of screw shafts, converts the rotational force of the screw shaft into a moving force of an injection plate by a nut member, and injects resin. When power is transmitted by the drive pulley on the electric motor side and the timing belt provided on the driven pulley on the screw shaft side, the timing belt is provided for each drive pulley so that the ball screw shaft receives power transmission from a plurality of electric motors. It is individually provided over each driven pulley.
[0008]
Further, the present invention relates to a molding machine that transmits a rotational force of one electric motor to a plurality of nut members, converts the rotational force of the nut member into a moving force of an injection plate by a screw shaft, and injects resin. When power is transmitted by a timing belt provided on a drive pulley on the electric motor side and a driven pulley on the nut member side, the timing belt is individually provided over the drive pulley and each driven pulley. .
[0009]
Further, the present invention relates to a molding machine that transmits the rotational force of a plurality of electric motors to a plurality of nut members, converts the rotational force of the nut member into a moving force of an injection plate by a screw shaft, and injects resin. When the power transmission is performed by the drive pulley on the electric motor side and the timing belt provided on the driven pulley on the nut member side, the timing belt is provided for each drive pulley so that the nut member receives power transmission from the plurality of electric motors. It is individually provided over the driven pulley.
[0010]
Still further, according to the present invention, at least one of the plurality of timing belts is provided with an idler pulley for adjusting belt tension.
[0011]
In the above configuration, the timing belt is provided on the plurality of driven pulleys in a one-to-one relationship with the drive pulleys regardless of the number of the drive pulleys and the driven pulleys. , The distortion of the screw shaft, which is likely to occur when it is provided, is reduced, and the life of the mechanism is maintained long. In addition, a large number of meshing teeth of the timing belt in the driven pulley are secured, and the meshing is performed in a wide range, so that an uneven load is less likely to occur during rotation in the driven pulley, and the load on the timing belt is reduced. Will also contribute.
[0012]
In the case of the timing belts provided individually for the driving pulley and the driven pulley, the belt length can be shortened, so that the tension can be easily adjusted. Even if the timing belt has a length, the idler pulley does not limit the belt length. Power can always be transmitted efficiently with the same belt tension.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
The figure shows an example of an injection device of an electric injection molding machine. The front and rear plates 3 and 4 connected to the upper surface of the machine base 1 by a tie bar 2 and the front and rear plates are inserted through the tie bar 1 and advance and retreat between the front and rear plates. An injection plate 5 provided freely, a pair of left and right ball nut members 6 and 6 mounted in through holes on both sides of the injection plate 5, and front and rear plates 3 And a pair of left and right ball screw shafts 7, 7 rotatably provided over one or the other, and an electric motor 8 such as an electric servo motor mounted on the upper portion of the rear plate 4 with one of the ball screw shafts 7, 7 biased. Consists of
[0014]
In such an injection device, the rotational force of the ball screw shafts 7, 7 by the electric motor 8 is converted into the forward moving force of the injection plate 5 by the ball nut members 6, and thereby the heating cylinder attached to the front plate 3 The injection plate 5 to which the injection screw 3a is connected is configured to move forward with the injection screw and to inject the resin.
[0015]
As a power transmission mechanism of the injection device, a toothed drive pulley 10 having a double pulley having the same outer diameter is attached to a drive shaft 9 of an electric motor 8. At the shaft ends of the ball screw shafts 7, 7, toothed driven pulleys 11, 12 having a diameter larger than that of the driving pulley 10 are attached. Timing belts 13, 14 are attached to the driven pulleys 11, 12 from the driving pulley 10. It is provided individually. As a result, the torque of one electric motor 8 is simultaneously transmitted to the ball screw shafts 7, 7 by the timing belts 13, 14, so that the injection plate 5 moves forward.
[0016]
An idler pulley 15 for adjusting belt tension attached to the rear plate 4 is provided on the return side of the longer timing belt 14 provided on the driven pulley 12 distant from the electric motor 8. Thus, the timing belt 14 is adjusted to the belt tension of the shorter timing belt 13, and power can be transmitted to both driven pulleys 11 and 12 by the same belt tension. The tension adjustment by the idler pulley 15 is also effective for the shorter timing belt 13, and when the belt length increases due to an increase in the size of the apparatus, it is preferable to provide the idler pulley 15 on both of them.
[0017]
FIG. 4 shows a case where two electric motors 8 and 8a are used to drive the pair of left and right ball screw shafts 7 and 7 at the same time due to the necessity of large power due to the increase in the size of the molding machine. And the driven pulleys 11 and 12 are also double pulleys. As in the case of FIG. 2, the belt is hooked from the drive pulleys 10 and 10a of the drive shafts 9 and 9a of the electric motors 8 and 8a to the driven pulleys 11 and 12 of the ball screw shafts 7 and 7, respectively. , 13a and 14a are provided individually, and idler pulleys 15 and 15a are also in contact with timing belts 14 and 14a provided on pulleys remote from the respective electric motors 8. Thus, the rotational force of both electric motors 8, 8a is simultaneously transmitted to the ball screw shafts 7, 7, and the ball screw shafts 7, 7 can be driven to rotate by both electric motors 8, 8a.
[0018]
FIG. 5 shows a ball screw shaft 7 fixed on the front and rear plates 3 and 4 by screwing the rotation of the ball nut members 6 and 6 of the injection plate 5 on the rotation side. 7 show an embodiment of a power transmission mechanism that converts the moving force of the injection plate 5 to inject the resin.
[0019]
As in the above embodiment, a toothed drive pulley 10 of a double pulley having the same outer diameter is attached to a drive shaft 9 of an electric motor 8 indicated by a chain line above the injection plate 5. In addition, driven pulleys 11 and 12 having teeth with a diameter larger than that of the drive pulley 10 are attached to the ends of the ball nut members 6 and 6, respectively. The timing belts 13 and 14 are individually hung on the 12. As a result, the rotational force of one electric motor 8 is simultaneously transmitted to the ball nut members 6 and 6 by the timing belts 13 and 14, and the rotation is moved by the ball screw shafts 7 and 7 at fixed positions to move the injection plate 5. Is converted to The belt session is adjusted by an idler pulley (not shown) in the same manner as in the above embodiment.
[0020]
In the case where two electric motors are used and the pair of left and right ball nut members 6 and 6 are driven to rotate at the same time, although not shown in the drawing, the driven pulley attached to the ball nut member is double as in the case shown in FIG. In the same way as in the case of FIG. 4, a belt is hooked from the drive pulley on each electric motor side to a driven pulley of each ball nut member, and a timing belt is individually provided. Abut the timing belt provided on the pulley on the side away from the pulley. As a result, the rotational force of both electric motors is simultaneously transmitted to each ball nut member, and the rotation of the ball nut members is converted by both electric motors into the moving force of the injection plate by the ball screw shaft, thereby injecting the resin. Is
[0021]
In any of the above embodiments, regardless of the number of the driving pulleys 10 and 10a and the number of the driven pulleys 11 and 12, the timing belts 13, 14, 13a and 14a are provided in a plurality of one-to-one relation with the driving pulleys 10 and 10a. Since the tension is applied to the driven pulleys 11 and 12, the tension applied to the timing belts does not strongly act on the driven pulleys 11 and 12, and therefore, the distortion of the ball screw shafts 7 and 7 due to the passage of time is prevented. The mechanism has a long life and can contribute to miniaturization.
[Brief description of the drawings]
FIG. 1 is a plan view in which a part of an injection device having a power transmission mechanism according to the present invention is cut away.
FIG. 2 is a rear view of the same.
FIG. 3 is a side view of a rear portion of the apparatus.
FIG. 4 is an explanatory view showing a power transmission mechanism between two electric servomotors and a pair of left and right ball screw shafts.
FIG. 5 is a plan view in which a part of the embodiment when the nut member is rotated is cut away.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Machine stand 3 Front plate 4 Rear plate 5 Injection plate 6 Ball nut member 7 Ball screw shaft 8 Electric motor 9 Drive shaft 10 Drive pulley 11, 12 Follower pulleys 13, 13a, 14, 14a Timing belt 15 Idler pulley

Claims (5)

In a molding machine that transmits the rotational force of one electric motor to a plurality of screw shafts and converts the rotational force of the screw shaft into a moving force of an injection plate by a nut member to inject the resin, the power transmission is performed by an electric motor. Of the electric injection molding machine, characterized in that the timing belt is provided to be individually hung over the drive pulley and each driven pulley, when the timing belt is provided on the drive pulley on the side and the driven pulley on the screw shaft side. Power transmission mechanism. In a molding machine that transmits a rotational force of a plurality of electric motors to a plurality of screw shafts and converts the rotational force of the screw shafts into a moving force of an injection plate by a nut member to inject the resin, the power transmission is performed by an electric motor. The timing belt is individually extended over each driven pulley so that the ball screw shaft receives power transmission from a plurality of electric motors when performing the driving with the driving pulley on the side and the timing belt provided on the driven pulley on the screw shaft side. A power transmission mechanism for an electric injection molding machine, wherein In a molding machine that transmits a rotational force of one electric motor to a plurality of nut members and converts the rotational force of the nut members into a moving force of an injection plate by a screw shaft to inject resin, the power transmission is performed by an electric motor. The timing belt provided on the drive pulley on the side of the nut member and the driven pulley on the side of the nut member, wherein the timing belt is individually provided over the drive pulley and each driven pulley. Power transmission mechanism. In a molding machine that transmits the rotational force of a plurality of electric motors to a plurality of nut members and converts the rotational force of the nut members into a moving force of an injection plate by a screw shaft to inject resin, the power transmission is performed by an electric motor. The timing belt is individually extended over each driven pulley for each driving pulley so that the nut member receives power transmission from a plurality of electric motors when performing the driving with the driving pulley on the side and the timing belt provided on the driven pulley on the nut member side. A power transmission mechanism for an electric injection molding machine, wherein the power transmission mechanism is provided by hanging. 5. The power transmission mechanism of an electric injection molding machine according to claim 1, wherein at least one of the plurality of timing belts is provided with an idler pulley for adjusting a belt tension. .

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