JPH084909B2 - Valve structure of degassing device in injection molding machine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve structure in a degassing device for an injection molding machine such as a die casting, and more particularly to a contact formed by a seat surface of a valve head and a valve seat. TECHNICAL FIELD The present invention relates to a valve structure for a gas venting device, which is capable of exhibiting stable sealing performance over a long period of time by reducing the angle of inclination of the corner and the corner of the valve head.

(Prior Art) Examples of injection molding machines include those shown in JP-A-56-47257 and JP-A-56-47260. This will be described with reference to FIG. FIG. 8 is a sectional view showing the structure of the injection molding machine. First, the fixed mold 1 and the movable mold 3 are arranged. A runner 5 is formed between the fixed mold 1 and the movable mold 3, and a cavity 9 is formed above the runner 5 in the drawing through a gate 7.

A casting sleeve 11 is inserted in the lower portion of the fixed mold 1 in the drawing and communicates with the runner 5.
A pouring port 13 is formed on the side surface of the casting sleeve 11 on the right side in the figure, and the melt to be injected is poured through the pouring port 13.

A plunger 15 is accommodated in the casting sleeve 11 so as to be slidable in the left-right direction in the drawing. This plunger 15
Is connected to an injection cylinder 19 via a plunger rod 17, and the injection cylinder 19 is driven appropriately to slide in the casting sleeve 11.

A striker 21 is attached to the end of the injection cylinder 19 on the plunger 15 side.On the other hand, a vacuum start limit switch 23 and a high-speed limit switch 25 are arranged at predetermined positions along the travel path of the striker 21. There is.

A gas vent passage 29 is formed in the upper end 27 of the cavity 9 so as to communicate with the cavity 9. A vacuum suction device 33 is connected to the gas vent passage 29 via a pipe 31. This vacuum suction device 33 includes an electromagnetic switching valve 35 and a tank.
37, a vacuum pump 39, and a drive motor 41. The electromagnetic switching valve 35 has switching positions 35a and 35b. By switching to the switching position 35a, the gas vent passage 2
9 and the vacuum suction device 33 are connected.

An on-off valve 43 is inserted in the gas vent passage 29.
The open / close valve 43 is opened / closed by a valve drive mechanism 45. That is, the on-off valve 43 is composed of the valve body 47 and the shaft 49, and the shaft 49 is connected to the piston 53 slidably accommodated in the cylinder 51.

On the other hand, a compressor 55 is installed, and compressed air from the compressor 55 is supplied to the electromagnetic switching valve 57 and the pipes 59, 61.
Are supplied to the inside of the front chamber 63 or the rear chamber 65 of the cylinder 51, respectively. Thereby, the piston 53 is slid to the left or right in the figure, the valve body 47 is brought into contact with or separated from the seat portion 67, and the valve is opened or closed. The solenoid switching valve 57 has a switching position 57
It is equipped with a and 57b, and by switching to either,
Compressed air is supplied to the front chamber 63 or the rear chamber 65.

Further, a detection rod 69 is installed in the gas vent passage 29. The injection molten material pushed up by the detection rod 69 is detected, and the on / off of the electromagnetic switching valve 57 and the opening / closing of the on-off valve 43 are controlled via an electric circuit (not shown).

 The operation will be described based on the above configuration.

First, the molten material to be injected is injected from the pouring port 13 with the opening / closing valve 43 opened. At the same time, the injection cylinder 19 is driven to slide the plunger 15 leftward in the figure.

The slide of the plunger 15 closes the pouring port 13, and the striker 21 operates the vacuum start limit switch 23. Start limit switch 23
In response to the operation of, the electromagnetic switching valve 35 is switched to the switching position 35a via an electric circuit (not shown). By the operation of the electromagnetic switching valve 35, the gas vent passage 29 and the vacuum suction device 33 are communicated with each other, and the gas in the casting sleeve 11, the runner 5, and the cavity 9 is sucked and discharged through the gas vent passage 29 and the pipe 31. To be done.

When the plunger 15 further slides to the left side in the figure, the melt to be injected fills the cavity 9, and the degassing path 29
The melt to be injected contacts the detection rod 69 by being pushed out.
In response to the detection signal from the detection rod 69, the electromagnetic switching valve 57 is switched to the switching position 57b via an electric circuit (not shown).

By the operation of the electromagnetic switching valve 57, compressed air from the compressor 55 is supplied into the front chamber 63 of the cylinder 51,
The piston 53 retracts to the right in the figure. When the piston 53 retracts to a certain position, the valve body 47 is seated on the seat portion 67 and the valve is closed. By closing the opening / closing valve 43, the gas vent passage 29
Is shut off, and the vacuum suction by the vacuum suction device 33 is stopped.

(Problems to be Solved by the Invention) According to the above-described conventional configuration, there is a problem that the sealing performance of the on-off valve 43 and the seat portion 67 is impaired due to wear and deformation after long-term use. That is,
The inclination angle α ° of the opening / closing valve 43 with respect to the horizontal line of the valve body 43 on the seat portion 67 side and the inclination angle β ° of the seat portion 67 with respect to the horizontal line are set to the same angle. That is, the desired sealing performance is exhibited by mutual surface contact.

However, due to manufacturing errors and the like, α ° and β ° may be different from each other. Therefore, the inclined surfaces do not adhere to each other, and sealing is performed in the state shown in FIG. 9, for example. Become. As a result, the shape becomes an undercut, it becomes difficult to take out the product, and the valve body 43 may be pushed open by the molten metal during filling, so that the desired sealing performance is impaired.

To solve this problem, it is conceivable that the difference between the inclination angles α ° and β ° is set to a relatively large value in advance, instead of the seal structure based on the surface contact, for example, the structure shown in FIG.

However, in the case of such a structure, the mechanical strength of the corner portion of the valve body 47 of the on-off valve 43 is lowered, the corner portion collides with the seat portion 67 and is damaged, and the melt The seat may be deformed by the pressure, and desired sealing performance may be impaired.

The present invention has been made based on these points, and an object of the present invention is to provide a valve structure of a degassing device in an injection molding machine capable of stably maintaining desired sealing performance for a long period of time.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a valve seat formed on the mold side at a predetermined inclination angle, a seat surface formed facing the valve seat, and this seat surface Of the valve seat formed by the injection melt contact surface part continuously formed on the opposite valve seat side through the corner part, and the corner part is seated by reciprocating the valve rod connected to the valve head. In the valve structure of the degassing device in the injection molding machine which is opened and closed by being brought into and out of contact with each other, the contact angle formed by the valve seat and the seat surface is set to 1 ° or less.

Also, the angle of inclination of the corners was set to 5 ° or less with respect to the longitudinal direction of the valve rod, and a groove of arbitrary shape was formed on the end face of the valve head.

(Operation) Instead of making the seat surface tilt angle and the valve seat tilt angle equal to each other as in the prior art and making the surface contact with each other, the corner portion is seated on the valve seat so that the sealing function is exerted and the valve seat and The contact angle formed by the sheet surface was set to a small value of 1 ° or less.

As a result, the mechanical strength of the corner portion is improved, the corner portion is not damaged even if it collides with the valve seat, and stable sealing performance can be exhibited for a long period of time.

Also, by setting the angle of the corner to 5 ° or less, the corner 11
The stress concentration on 1 can be prevented, and the deformation of the corner portion 111 can be prevented even better.

Further, by forming a groove of an arbitrary shape on the end face of the valve head, for example, when another component is attached to the valve body by screwing, a jig can be inserted into the groove to regulate the rotation of the valve body. Therefore, workability is significantly improved.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. The valve structure according to this embodiment is configured as shown in FIG.

First, there is a valve body 101, and this valve body 101 comprises a valve head 103 and a valve rod 105. The valve head 103 is formed with a seat surface 107 and an injection melt contact surface 109. Further, a corner portion 111 is formed at a boundary portion between the sheet surface 107 and the injection melt contact surface 109.

On the other hand, a valve seat 115 is formed on the fixed mold 113 side. By seating the corner portion 111 of the seat surface 107 on the valve seat 115, a predetermined sealing performance is exhibited.

Next, the angle of each part will be described. First, the valve seat 115
The inclination angle X ° with respect to the horizontal direction (longitudinal direction of the valve rod) is set to 40 ° in this embodiment. On the other hand, an angle (hereinafter referred to as a contact angle) A ° formed by the valve seat 115 and the seat surface 107 is set to 1 °. That is, the contact angle A ° is set as small as possible within the manufacturing tolerance.

The angle obtained by adding the above-mentioned angles X ° and A ° is the seat surface.
The inclination angle of 107 becomes B °.

In this way, the inclination angle A ° is reduced because the corner portion 11
1 is to increase the mechanical strength, and the corner 111 is the valve seat 115.
It is designed so that it will not be damaged by mischief even if it collides with.
Further, the surface pressure acting on the valve seat 115 is reduced to reduce the deformation amount of the corner portion 111, and the corner portion 111 is used for a long time.
This is because, when is deformed, the contact area with the valve seat 115 is increased in accordance with the increase in the amount of deformation.

Next, the corner portion 111 will be described. As shown in FIG. 2, the inclination angle θ of the corner 111 is set in the range of 0 to 5 ° (5 ° in the case of this embodiment). Further, the side surface distance Y of the corner portion 111 is set to 0.2 to 0.5 mm. The reason why the inclination angle range is set as described above is to prevent stress concentration on the corner portion 111 and prevent deformation of the corner portion 111 even better. Further, the side surface distance Y is set to 0.2 to 0.5 mm in order to prevent the corner portion from having a "galling" phenomenon and causing a problem in taking out the product. The side distance Y is not limited to the above numerical value as long as it is short enough not to cause a problem in taking out the product. Next, the valve head 103 will be described. As shown in FIGS. 3 and 4, the valve head 103
A negative groove 117 is formed in the groove. This is to prevent the valve body 101 from rotating when assembling components not shown in the valve body 101 by screwing. That is, the groove 1
A jig (for example, a minus (-) type driver) not shown is inserted in 17 to regulate the rotation of the valve body 101.

Incidentally, the angles of the above-mentioned respective parts are collectively shown as shown in FIG.

As described above, according to this embodiment, the following actions and effects can be obtained. In the figure, C ° is the peripheral surface angle of the valve head 103, and is an angle that allows drafting.

First, by seating the angle 111 of the valve body 101 on the valve seat 115, the seal became more reliable.

At that time, since the contact angle A ° was set to 1 ° and was made as small as possible within the manufacturing allowable range, the mechanical strength of the corner portion 111 was improved, whereby the collision of the corner portion 111 with the valve seat 115 was caused. The corner portion 111 can be prevented from being damaged, and desired sealing performance can be stably maintained for a long period of time.

Also for the corner portion 111, by setting the inclination angle θ ° to 5 ° and setting the side portion distance Y to 0.2 to 0.5 mm,
Since the "galling" of the solidified melt to be injected is prevented, it is possible to prevent the loss of the sealing performance due to the "galling".

The above points will be described in detail with reference to FIGS. 6 and 7.

FIG. 6 and FIG. 7 show the results of analysis of the state of occurrence of equivalent stress when the angle of each part of the valve structure is changed. FIG. 6 (a) shows that the inclination angle X ° of the valve seat 115 is 40 °.
, The contact angle A ° of the seat surface 107 is set to 2 °, and the angle θ ° of the angle 111 is set to 15 °. FIG. 6 (b)
FIG. 6 (c) shows the case where the inclination angle X ° of the valve seat 115 is set to 40 °, the contact angle A ° of the seat surface 107 is set to 1 °, and the angle θ ° of the corner portion 111 is set to 5 °. Is the tilt angle X of the valve seat 115
40 °, contact angle A of the seat surface 107 2 °, corner 111
Shows the case where the angle θ ° of is set to 5 °.

The analysis was performed using ANSYS (a program manufactured by Cybernet System Co., Ltd.). The equivalent stress is calculated based on the strain energy theory.

As a result of the above analysis, the results shown in FIGS. 7 (a), (b) and (c) could be obtained. First, FIG. 6 (a)
In the case shown in Fig. 7 (a), the maximum stress is 2567 Kgf / mm ² , and in the case shown in Fig. 6 (b), the maximum stress is shown in Fig. 7 (b). Is 1470 Kgf / mm ² , and FIG. 6 (c) shows that the maximum stress is 2021 Kgf / mm ^{2 as} shown in FIG. 7 (c).

Thus, by setting the contact angle A ° to 1 °,
Also, by setting the inclination angle θ ° of the corner portion 111 to 5 °,
Equivalent stress can be reduced. Specifically, by setting the contact angle A ° to 1 °, the equivalent stress can be reduced by 42.6%, and by setting the inclination angle θ ° of the corner 111 to 5 °, the equivalent stress can be reduced by 21.1%.

The present invention is not limited to the above-mentioned embodiment, and various modifications and applications are possible. For example, the contact angle A ° may be 1 ° or less, and need not be 1 °. Also, regarding the inclination angle θ ° of the corner portion 111, 0
It may be set arbitrarily within a range of up to 5 °.

Further, the shape of the groove 117 is arbitrary, and may be a plus (+) shape or another shape.

(Effects of the Invention) According to the valve structure of the degassing device in the injection molding machine according to the present invention as described above in detail, the desired sealing performance can be maintained for a long time by reducing the contact angle and the angle of inclination of the corners. It can be kept stable.

Further, by forming a groove on the end surface of the valve head to allow the jig to be inserted, the mounting work by screwing other parts into the valve body is facilitated.

[Brief description of drawings]

1 to 7 are views showing an embodiment of the present invention, FIG. 1 is a sectional view of a valve structure, FIG. 2 is a view showing a corner portion of a valve body,
3 is a side view of the valve body, FIG. 4 is a front view of the valve body, FIG. 5 is a view showing angles of various parts of the valve mechanism, FIG. 6 (a),
(B) and (c) are diagrams showing samples of stress analysis, FIGS. 7 (a), (b) and (c) are diagrams showing results of stress analysis, and FIGS. 8 to 10 are conventional examples. FIG. 8 is a sectional view showing the structure of the injection molding machine, and FIGS. 9 and 10 are sectional views of the valve structure. 101 ... Valve element, 103 ... Valve head, 105 valve rod, 107 ... Seat surface, 109 ... Injected molten material contact section, 111 ... Corner section, 113 ...
… Fixed mold (mold), 115 …… Valve seat, 117 …… Groove, X °…
… Valve seat inclination angle, A ° …… Contact angle, θ ° …… Corner angle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Publication 3-5901 (JP, B2) Actual Public Publication 3-4430 (JP, Y2) Actual Public Publication 7-18462 (JP, Y2)

Claims (3)

[Claims] 1. A valve seat formed on a mold side at a predetermined inclination angle, a seat surface formed facing the valve seat, and a seat surface opposite to the seat surface, which is continuously formed via a corner portion. A valve head formed by the contact surface of the melt to be injected and a valve rod connected to the valve head is reciprocally moved to open and close the corner of the valve seat by opening and closing the valve seat. In the valve structure of the apparatus, the contact angle formed by the valve seat and the seat surface is 1 ° or less. 2. A valve structure for a degassing device in an injection molding machine according to claim 1, wherein the angle of inclination of the corners is 5 ° or less with respect to the longitudinal direction of the valve rod. 3. The valve structure of a degassing device in an injection molding machine according to claim 1, wherein a groove having an arbitrary shape is formed on an end surface of the valve head.