JPH0344505Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an improvement of a molded product ejecting device used in plastic injection molding.

(Prior Art) In recent years, automatic ejection devices have been used in plastic injection molding to automatically and continuously eject molded products from a molding machine. This type of molded product ejecting device often uses a combination of a ball screw and servo motor that allows for precise positioning.
The ejection head is moved up and down to a predetermined height by rotating the ball screw through a predetermined angle using a servo motor.

(Problem that the invention aims to solve) However, in the conventional lifting mechanism, the head body is directly raised and lowered by a ball screw, so when the head is raised and lowered, the load due to the weight of the head body is directly applied to the servo motor via the ball screw. It will be loaded. The head body is equipped with a back-and-forth movement mechanism and a chuck mechanism for taking out the product.
Since it weighs about 50 kg, a servo motor with a large drive torque is required to support this load and move it up and down.

However, using a high-output servo motor not only causes economical problems such as high cost, but also imposes design constraints on the selection and arrangement of related parts. In addition, the heavy loads applied to ball screws and nuts, which require high precision, shorten the lifespan of these parts and
Do not do this as it may cause malfunction and deteriorate the dynamic characteristics of the entire device.

This invention was proposed in view of the above-mentioned problems, and mainly consists of an injection molded product ejecting device having a structure in which the load due to the weight of the head body is not directly applied to the servo motor via the ball screw when the head is raised and lowered. This is what we are trying to provide.

(Means for Solving the Problems) That is, this invention provides a molded product ejecting device having a head body configured to be movable up and down by a ball screw rotated by a servo motor.
The present invention relates to an injection molded product removal device characterized in that an elevating cylinder is provided for moving the head main body up and down in conjunction with the servo motor.

(Function) When the servo motor operates to raise the head body, the lifting cylinder linked to the servo motor extends and applies upward force to the head body with its pressure, reducing the head body's own weight. Reduces the load on the servo motor due to Thereby, the servo motor is rotated by a predetermined angle with low torque to rotate the ball screw, and the head body can be raised to a predetermined position.

Furthermore, when lowering the head body, the elevating cylinder is retracted. For example, the pressurization of the lifting cylinder is released and the back pressure of the lifting cylinder is used to hold the head body. Therefore, in the same way as when raising the head, the servo motor is rotated by a predetermined angle with a low driving torque, and the ball screw is rotated in the opposite direction, so that the head main body can be lowered to a predetermined position.

(Example) An embodiment of this invention will be described below with reference to the attached drawings. Fig. 1 is an overall side view of a molded product ejecting device showing an embodiment of this invention, and Fig. 2 is a side view of the molded product ejecting device shown in Fig. 1. FIG. 2 is a cross-sectional view showing the main parts of the lifting mechanism in the molded product take-out device together with a circuit diagram of a cylinder.

The molded product ejecting device 10 of the embodiment includes a head main body 5
This is a device for automatically and continuously taking out molded products from a plastic injection molding machine (not shown) using a chuck portion 57 at the tip of an arm portion 55. As shown in FIG. 1, the molded product ejecting device 10 is composed of a base plate 20, a truck 30, a vertical column 40, and a head body 50. It is configured to be movable in the front-rear (front and back) direction, left-right direction, and up-down direction, and to be freely pivotable about the vertical column 40.

That is, first, the rail 1 provided on the floor 15
A base plate 20 is mounted on 6 via wheels 17 so as to be movable in the front and back directions in the figure.

A trolley 30 is mounted on the base plate 20 so as to be movable in the left and right directions in the figure. Reference numeral 21 in Figure 1
23 is a guide rail, 23 is a ball screw provided in parallel with the rail guide 21, and 24 is a longitudinal servo motor 24 for rotating the ball screw 23. Reference numeral 31 represents a roller provided at the bottom of the truck 30 and runs along the guide rail 21, and 33 represents a nut screwed onto the ball screw 23 to move the truck 30 back and forth.

Further, a vertical column 40 is erected on the truck 30 so as to be able to rotate freely, and a rotation servo motor 41 is provided.
It is configured to rotate at a predetermined angle with respect to the trolley 30.

A head body 50 is attached to the vertical column 40.
is attached so that it can be raised and lowered.

The head body 50 has an arm portion 55 that expands and contracts in the left and right directions in the figure, and is driven by a back and forth servo motor 54.
A chuck portion 57 at the tip of the arm portion 55 is moved back and forth with respect to a molded product take-out portion of a molding machine (not shown) by a ball screw 56 rotated by a ball screw 56 .

Note that if this arm portion 55 is expanded a little, this head body 50 will be removed when the molded product is taken out.
The arm 55 held at
The speed can be made a composite of the forward and backward movement speed of the carriage 30 and the backward and forward movement speed of the trolley 30, and the throughput for taking out the molded product in injection molding with a short molding cycle can be further improved.

As shown in FIG. 2, the head body 50 of this invention is enclosed in the vertical column 40, and includes a ball screw 65 rotated by an elevating servo motor 60, and a ball screw 65 that connects the head body 50 and the truck. It is configured to be movable up and down by a lifting cylinder 70 attached between 40 mounting plates 45. Reference numeral 42 in FIG. 1 represents a keyway.

The driving torque of the elevating servo motor 60 is transmitted to a ball screw 65 via a gear device 61, and via a nut 67 attached to the head main body 50, raises and lowers the head main body 50.

As the lifting cylinder 70, a pneumatic or hydraulic double-acting cylinder is used here. In FIG. 2, reference numeral 71 is a cylinder chamber, 72 and 73 are pressure fluid conduits, reference numeral 80 in the circuit diagram is a pressure source such as an air source, 81 is a flow rate regulating valve, and 82 is a pressure control that regulates the circuit pressure to a constant level. A valve 83 is a switching valve that switches the operation of the cylinder. This switching valve 8
Reference numeral 3 is an electromagnetic type, which is constructed in conjunction with the operation of the lifting servo motor 60.

Next, an example of the operation of the elevating mechanism of this invention will be explained.

First, when the head body 50 is raised, the solenoid of the switching valve 83 is energized by an electric signal, and the cylinder chamber 71 is filled with air from the pump 80. Since the lower end of the cylinder rod 74 of the cylinder 70 is fixed to the mounting plate 45 of the truck 40 as shown in the figure, an upward force is generated on the cylinder body as the cylinder chamber 71 expands, and the cylinder body is attached. Push the head body 50 upward.

Along with the operation of the cylinder 70, the lifting servo motor 60 rotates by a predetermined angle to rotate the ball screw 65. As shown in the figure, the lower end of the ball screw 65 is connected to the mounting plate 40 of the truck 40, which is the same as the cylinder rod 74.
The rotation of the ball screw 65 raises the head body 50 to a predetermined position via a nut 67.

When lowering the head body 50, the solenoid of the switching valve 83 is demagnetized by an electric signal and the back pressure of the fluid circuit is used to lower the head body 50.
Holds 0. At the same time, the elevating servo motor 60 rotates a predetermined angle in the opposite direction to the upward movement, and the ball screw 6
5 to lower the head main body 50 to a predetermined position.

According to research by the present inventors, when the weight of the head body 50 is 50 kg, the upper lifting cylinder 70
Apply upward force to hold the head at
To generate 40kg, a lifting servo motor with an output of around 400W would have been required, but
It can be replaced with a lifting servo motor with an output of about 100W.
It has become clear that it is possible to reduce the cost of the lifting device drive by 30-40%.

(Effects) As shown and explained above, in this invention, in a molded product ejecting device having a head body configured to be freely raised and lowered by a ball screw rotated by a servo motor, Since a lifting cylinder is provided to move the head body up and down, the load applied to the servo motor and the ball screw and nut when the head body is raised and lowered can be significantly reduced. As a result, a small servo motor with low output can be used, and the cost of the device can be kept low and power consumption can be reduced. Furthermore, by reducing the weight of the servo motor placed on the top of the vertical column, the center of gravity of the device can be stabilized, improving dynamic characteristics.

Furthermore, the miniaturization of servo motors has suppressed wear and damage to precision parts such as ball screws and nuts, making it possible to extend the lifespan of these parts.

[Brief explanation of drawings]

Fig. 1 is an overall side view of a molded product ejecting device showing an embodiment of this invention, and Fig. 2 is a cross section showing the main parts of the lifting mechanism in the molded product ejecting device shown in Fig. 1 together with a circuit diagram of the cylinder. It is a diagram. 10... Molded product removal device, 20... Base plate,
30...Dolly, 40...Vertical column, 50...Head body, 55...Arm part, 57...Chuck part, 60...Elevating servo motor, 65...Ball screw, 70...Elevating cylinder, 83... ...Switching valve.

Claims (1)

[Scope of utility model registration request] A molded product take-out device having a head body configured to be freely raised and lowered by a ball screw rotated by a servo motor, characterized in that a lifting cylinder is provided for moving the head body up and down in conjunction with the servo motor. An injection molded product removal device.