JPH0481928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for aligning the nozzle of an injection molding machine when the nozzle is pressed against a mold.

(Prior Art) Generally, in an injection molding machine, as shown in FIG.
By operating a shift cylinder 3 attached to the slide base 2, the screw cylinder 4 of the injection device 1 is moved forward or backward. . At the time of injection, the screw cylinder 4 is advanced and the nozzle 5 at the tip is connected to the fixed platen 6.
The nozzle 5 is pressed against the mold 7 fixed to the
The molten resin is injected into the cavity through the sprue 8 of the mold 7.

The fixed platen 6 is provided with a nozzle insertion hole 9 through which the nozzle 5 is inserted from the back side and pressed against the mold 7. The mold 7 also has a sprue bushing 1 on its back side as a nozzle receiving part.
0 is set. As shown in an enlarged view in FIG. 6, the nozzle receiving surface 10a of the sprue bushing 10 is usually a concave spherical surface with a radius of curvature that is the same as or slightly larger than the convex spherical surface at the tip of the nozzle 5. There is.

In such an injection molding machine, in order to prevent resin from leaking from between the nozzle 5 and the sprue bushing 10 during injection of molten resin,
As shown in FIG. 6, it is necessary to align the center of the nozzle 5 with the center of the sprue bushing 10. However, in reality, the fixed platen 6 of the mold 7
It is normal for the centers of the nozzle 5 and the sprue bushing 10 to be misaligned, as shown in FIG. 7, due to installation errors in the slide base 2, injection device 1, and screw cylinder 4. It is. Therefore, every time the mold 7 is replaced,
It has become necessary to align the nozzle 5.

In order to align the nozzle 5 in this manner, the slide base 2 that supports the injection device 1 is configured such that its position can be adjusted in the vertical and horizontal directions. Normally, adjusting bolts 11 and 12 as shown in FIG. 5 are used as the vertical position adjustment mechanism. The adjusting bolts 11 and 12 are screwed into the slide base 2, and their lower ends are brought into contact with the bed 13 of the injection molding machine.
Therefore, by rotating the adjusting bolts 11 and 12, the slide base 2 and the injection device 1 are moved in the vertical direction, and the vertical position of the nozzle 5 is adjusted. After the slide base 2 is adjusted, it is pressed and fixed against the bed 13 by a holding bolt 14. The horizontal position adjustment mechanism of the slide base 2 is similarly configured.

When aligning the nozzle 5 using such a mechanism, conventionally, the nozzle 5 and the sprue bushing 1
Adjustment bolts 11, 12, etc. were operated while visually confirming the contact state of zero.

(Problems to be Solved by the Invention) However, such adjustment based on visual confirmation is inevitably inaccurate. In particular, in recent years, there has been a tendency to thicken the fixed platen 6 to increase its rigidity due to the demand for precision molding.
The nozzle insertion holes 9 provided in the fixed platen 6 are becoming deeper and narrower. It is extremely difficult to visually confirm the state of contact between the tip of the nozzle 5 located at the back of such a deep and narrow hole and the sprue bushing 10. As a result, the work of aligning the nozzle 5 is becoming less and less complete.

If the molding operation continues with insufficient alignment between the nozzle 5 and the sprue bushing 10, the convex spherical surface at the tip of the nozzle 5 and the concave spherical surface of the sprue bushing 10 will wear unevenly due to the pressing force of the shift cylinder 3. Resulting in. And like that nozzle 5
The tip of the nozzle receiving surface 1 of the sprue bushing 10 may be attached to an injection molding machine whose tip is unevenly worn.
If the mold 7 with uneven wear on 0a is attached to another injection molding machine, the seal at the contact surface between the nozzle 5 and the sprue bushing 10 may become incomplete, causing resin leakage, or uneven wear may occur. This may cause uneven wear on the other parts.

In addition, in order to visually check the contact state between the nozzle 5 and the sprue bushing 10 through the deep and narrow nozzle insertion hole 9, it is necessary to
There is also the problem of having to bring your face close to the Furthermore, in the case of a large injection molding machine, the nozzle 5 is far away from the slide base 2, so
It is also impossible to adjust the adjusting bolts 11, 12, etc. provided on the slide base 2 while looking at the nozzle 5.

The present invention was made in view of these problems, and its main purpose is to accurately center the nozzle without directly visually checking the contact state between the nozzle and the nozzle receiving part of the mold. The goal is to make it possible to make adjustments.

Another object of the present invention is to make it possible to check the alignment of a nozzle even at a location far away from the nozzle.

Yet another object of the invention is to allow nozzle alignment to occur automatically.

(Means for solving the problem) In order to achieve this object, in the nozzle alignment method according to the present invention, when the nozzle at the tip of the screw cylinder is pressed against the nozzle receiving part of the mold, the two A bend in the axial direction that occurs in the nozzle due to misalignment is detected, and the position of the nozzle is adjusted in a direction that reduces the bend.

Further, the nozzle alignment device of the present invention used to carry out the method includes a bending detector that detects the bending of the nozzle in the axial direction, and the amount and bending of the nozzle detected by the bending detector. It is equipped with a turn indicator that displays the direction.

The nozzle alignment device of the present invention, which directly implements the method, includes a vertical position adjustment device and a horizontal position adjustment device that can adjust the vertical and horizontal positions of the nozzle, respectively, and a nozzle bending device in the axial direction. The present invention includes a bending detector for detecting the bending, and a control device that operates each position value adjusting device according to the amount and direction of bending of the nozzle detected by the bending detector.

(Function) As mentioned above, the nozzle receiving surface of the mold is a concave spherical surface, so if the nozzle is pressed against the nozzle receiving surface with incomplete alignment,
The tip of the nozzle slides along its concave spherical surface, exerting a strong bending force perpendicular to the nozzle axis. As a result, the nozzle is slightly bent toward the center of the nozzle receiving surface.

Therefore, as in the method of the present invention, by moving the nozzle in a direction that reduces the axial bending of the nozzle, the nozzle and the nozzle receiving portion of the mold can be aligned. Since the bending of the nozzle can be easily and accurately detected by using a strain gauge or the like, the centering can be performed accurately.

Furthermore, by displaying the amount and direction of bending of the nozzle on the bending indicator, it is possible to grasp the amount and direction of deviation of the nozzle with respect to the center of the nozzle receiving portion. Therefore, it is possible to perform nozzle centering work even at a location far away from the nozzle.

Furthermore, by activating the vertical position adjustment device and horizontal position adjustment device of the nozzle depending on the amount and direction of the nozzle bending, the nozzle can be automatically adjusted just by pressing it against the mold. A reconciliation will take place.

(Example) Hereinafter, an example of the present invention will be described using the drawings.

In the following examples, the basic structure of the injection molding machine is the same as that of the conventional one shown in Figs. Omitted.

In the drawings, Figures 1 and 2 show an embodiment of a nozzle alignment device used to carry out the nozzle alignment method according to the present invention, and Figure 1 is a side view of the main parts thereof. FIG. 2 is a cross-sectional view of the nozzle portion.

As is clear from these figures, four high-temperature strain gauges 20 are installed on the upper, lower, left, and right sides of the outer peripheral surface of the nozzle 5.
₁ , 20 ₂ , 20 ₃ , and 20 ₄ are attached in the axial direction of the nozzle 5, respectively. These strain gauges 2
0 ₁ to 20 ₄ are covered by a flexible protective cover 21 attached to the outer periphery of the nozzle 5 . In this way, when the nozzle 5 bends in a direction perpendicular to the axis, the resulting strain on the outer surface of the nozzle 5 is detected by the strain gauges 20 ₁ to 20 ₄ . That is, these four strain gauges 20 ₁ to 2
0 ₄ and a protective cover 21, a bending detector 22 detects bending of the nozzle 5 in the axial direction.
is configured.

The lead wires 23 of each of the strain gauges 20 ₁ to 20 ₄ are combined into one cable 24 and connected to a bend indicator 25
It is connected to the. Inside the bending indicator 25, the amount of strain on the upper and lower outer surfaces of the nozzle 5 detected by the upper and lower strain gauges 20 ₁ and 20 ₂ (hereinafter, tensile strain is detected as a positive value and compressive strain is detected as a negative value) ), and the amounts of strain on the left and right outer surfaces of the nozzle 5 detected by the left and right strain gauges 20 ₃ and 20 ₄ are compared and calculated, respectively, and the display lamps 26 ₁ and 26 ₂ on the side with the larger amount of strain are , 26 ₃ or 26 ₄ are turned on, and the difference in the amount of distortion is digitally displayed on the display meter 27a or 27b.

When aligning the nozzle 5 using such a nozzle alignment device, the shift cylinder 3 (see FIG. 5) is operated to move the injection device 1 forward, and the nozzle 5 at the tip of the screw cylinder 4 is moved forward.
is pressed against the sprue bushing 10 which is the nozzle receiving part of the mold 7.

At this time, if the center of the nozzle 5 is eccentric above the center of the sprue bushing 10 as shown in FIG. Become. Then, the nozzle receiving surface 10
a is a concave spherical surface, and the nozzle 5 is pressed against the nozzle receiving surface 1 by the pressing force of the shift cylinder 3.
By being pressed against 0a, nozzle 5
The tip of the nozzle tends to slide along the nozzle receiving surface 10a toward the center thereof. As a result, the nozzle 5 is slightly bent toward the center line of the nozzle receiving surface 10a. That is, the nozzle 5 is pushed downward. The magnitude of the bend increases as the amount of eccentricity of the nozzle 5 increases.

When the nozzle 5 bends downward in this way, the strain gauge 20 ₁ attached to its upper surface detects a larger amount of strain than the strain gauge 20 ₂ on the lower surface. Therefore, the corresponding display lamp 26 ₁ lights up. That is, the indicator lamp 26 ₁ indicates that the nozzle 5 is eccentric upward and curved downward. When the nozzle 5 is eccentric downward, the indicator lamp ₂₆₂ lights up.

Then, the difference in the amount of strain detected by the upper and lower strain gauges 20 ₁ and 20 ₂ is indicated by the display lamps 26 ₁ and 26 ₂
It is digitally displayed on the display meter 27a between. The difference in the amount of distortion becomes larger as the nozzle 5 becomes more curved. Therefore, the numerical value displayed on the display meter 27a indicates the amount of vertical bending of the nozzle 5, that is, the amount of eccentricity.

When the nozzle 5 is eccentric in the left-right direction with respect to the center line of the sprue bushing 10, the indicator lamp 26 ₃ or 26 ₄ corresponding to the direction of eccentricity lights up, and the indicator 27b between them indicates a bend corresponding to the amount of eccentricity of the nozzle 5. The amount will be displayed. Further, when the nozzle 5 is eccentric in an oblique direction, one of the indicator lamps 26 ₁ and 26 ₂ indicating up and down and one of the indicator lamps 26 ₃ and 26 ₄ indicating left and right are lit at the same time, and each indicator 27a and 27b is turned on. The amount of bending of the nozzle 5 in the vertical and horizontal directions is displayed respectively.

In this way, the direction and amount of eccentricity of the nozzle 5 can be grasped by the display on the bending indicator 25. Therefore, the bend indicator 2
Adjust the adjusting bolts 11, 12, etc. while watching 5, and adjust the nozzle 5 in the direction that reduces the bending of the nozzle 5.
by moving the nozzle 5 to the sprue bushing 10.
can be accurately aligned. In that case, the bend indicator 25 indicates the adjuster bolt 1.
Since it can be installed near 1 and 12, it becomes easier to perform work while looking at it.

Note that in the above embodiment, the bending detector 2
2, four uniaxial strain gauges 20 ₁ to 20 ₄ are used, but it is also possible to use biaxial or triaxial strain gauges. In this way, the number of strain gauges can be reduced to two or one. Moreover, a bending detector other than a strain gauge can also be used.

Furthermore, in the above embodiment, the bend indicator 25
It is assumed that the difference in the amount of distortion is displayed as is on the display meters 27a and 27b, but by multiplying this by a coefficient preset on the bending display 25, a value that is easier to understand, for example, the actual nozzle 5.
It is also possible to display the amount of eccentricity.

The amount of strain detected by each of the strain gauges 20 ₁ to 20 ₄ is taken as the difference between before the nozzle 5 contacts the sprue bush 10 and after it is pressed, and the timing of the detection is generally determined by the limit switch. The setting is performed using a timer or the like, but the switching may be performed while visually observing the switch.

3 and 4 are a side view and a plan view showing an embodiment of a nozzle alignment device in which nozzle alignment is automatically performed using the alignment method according to the present invention.

As is clear from these figures, in this injection molding machine, the slide base 2 that supports the injection device 1 so as to be slidable in the front-rear direction extends along the upper surface of the base plate 30 installed on the bed 13.
It is configured to be able to slide in the left-right direction while being guided by guide rails 31, 31 fixed to the base plate 30. An adjustment shaft 33 is rotatably supported on a side wall of the slide base 2 by a bearing 32 attached to a base plate 30.
are screwed together. The adjustment shaft 33 is
It is designed to be rotationally driven by a motor 34 installed on the base plate 30.

Therefore, when the adjustment shaft 33 is rotated by the motor 34, the slide base 2 moves in the left-right direction, and the injection device 1 supported by the slide base 2 moves in the left-right direction. The position of the nozzle 5 is adjusted in the left-right direction. That is, in this embodiment, the motor 34, the adjustment shaft 33, and the slide base 2 constitute a horizontal adjustment device 35 for the nozzle 5.

On the other hand, two jack bolts 36, 36 and 37, 37 are screwed into the front and rear parts of the base plate 30, respectively. These jack bolts 36 and 37 pass through the base plate 30 in the vertical direction, and their lower ends abut against the upper surface of the bed 13. Worm wheels 38 and 39 are fixed to the upper ends of the jack bolts 36 and 37, respectively, and these worm wheels 38 and 39 are engaged with worms 42 and 43 provided on adjustment shafts 40 and 41, respectively. Each adjustment shaft 40, 41 is rotatably supported by bearings 44, 45 attached to the base plate 30, and is rotationally driven by motors 46, 47 installed on the base plate 30.

Therefore, the adjustment shaft 4 is rotated by the motors 46 and 47.
When the screws 0 and 41 are rotated, the worm wheels 38 and 39 that engage with the worms 42 and 43 are rotated, and the jack bolts 36 and 37 are rotated. As a result, the base plate 30 moves in the vertical direction, and the slide base 2 installed on the base plate 30 moves in the vertical direction together with the injection device 1. In this way, the position of the nozzle 5 at the tip of the screw cylinder 4 is adjusted in the vertical direction. When the rotational speeds of the motors 46 and 47 are varied, the base plate 30 is tilted up and down, and the vertical position and inclination of the nozzle 5 are changed. As described above, in this embodiment, motors 46, 47, adjustment shafts 40, 41, worms 42, 43, worm wheels 38, 39,
The jack bolts 36, 37 and the base plate 30 constitute a vertical position adjustment device 48 for the nozzle 5.

The base plate 30 is positioned relative to the bed 13 in the horizontal plane by positioning pins 49 fixed to the bed 13. The positioning pin 49 is configured to allow the base plate 30 to move in the vertical direction.

A bend detector 22 similar to the first and second embodiments is attached to the outer periphery of the nozzle 5. The detection signal from the bend detector 22 is transmitted to the cable 2
4 to an eccentricity detector 51 of a control device 50.

In the eccentricity detector 51, the bending detector 22
The amount of bending and bending direction of the nozzle 5 are calculated from the amount of distortion on the upper, lower, left and right outer surfaces of the nozzle 5 detected by The amount of eccentricity in the direction is calculated. The amount of eccentricity in the vertical direction is determined by the vertical direction adjuster 5 of the control device 50.
2, and the horizontal eccentricity is transmitted to the horizontal adjuster 53.

In the vertical adjuster 52, the eccentricity detector 5
The rotation direction and amount of rotation of the motors 46, 47 are determined based on the amount of vertical eccentricity given from 1, and the signals are sent to the motors 46, 47. Further, in the horizontal direction adjuster 53, based on the amount of horizontal eccentricity given from the eccentricity detector 51,
The direction and amount of rotation of the motor 34 are determined, and the signals are sent to the motor 34.

In the nozzle centering device configured as described above, when the shift cylinder 3 is operated to press the nozzle 5 against the sprue bush 10 of the mold 7, if the centers of the nozzle 5 and the sprue bush 10 do not coincide, The nozzle 5 bends toward the center line of the sprue bushing 10 with respect to its axial direction. Then, the bending is detected by the bending detector 22, and the operating amount of the vertical position adjusting device 48 and the horizontal position adjusting device 35 is determined in the control device 50 based on the bending amount and the bending direction.

Thus, the motors 46, 47 of the vertical position adjustment device 48 and the motor 34 of the horizontal position adjustment device 35 are actuated by signals from the control device 50. When the motors 46 and 47 operate, the front, rear, or both of the base plate 30 are lifted, the vertical position of the nozzle 5 is adjusted, and its vertical deviation is eliminated. Also,
When the motor 34 operates, the slide base 2 slides in the left-right direction, the left-right position of the nozzle 5 is adjusted, and its left-right deviation is eliminated.

In this way, according to this alignment device, the nozzle 5 is automatically aligned with the sprue bush 10. Therefore, for example, by setting an eccentricity tolerance in advance in the eccentricity detector 51 of the control device 50, even if the nozzle 5 becomes eccentric during the molding operation, it can be automatically corrected. I can do it.

In the embodiments shown in FIGS. 3 and 4, the vertical position adjustment devices 48 are provided at the front and rear parts of the base plate 30, but the center height of the nozzle 5 is set in advance to be sufficiently lower than the sprue bushing 10 or sufficiently lower than the sprue bushing 10. By setting it high, the adjustment device 48 can be provided only at either the front or the rear.
Furthermore, depending on the applicable model, it may be necessary to provide only either the vertical position adjustment device 48 or the horizontal position adjustment device 35.

Further, in the embodiment described above, the sliding mechanism of the slide base 2 is used to adjust the position of the nozzle 5 in the horizontal direction, but this can also be configured by a rotating mechanism.

The bending detector 22 does not have to be attached to the outer periphery of the nozzle 5, but the same function can be obtained even if it is attached to the small diameter portion of the tip of the screw cylinder 4 where it is relatively easy to bend.

(Effects of the Invention) As is clear from the above description, according to the present invention, the bending in the axial direction that occurs in the nozzle when the nozzle is pressed against the nozzle receiving portion of the mold is detected, and the bending is detected in accordance with the bending. Since the position of the nozzle is adjusted by using the nozzle, there is no need to visually check the contact state between the nozzle and the nozzle receiving part of the mold when aligning the nozzle, making the work easier. Furthermore, since it is possible to detect subtle misalignment of the nozzle that cannot be confirmed visually, uneven wear of the nozzle and mold can be prevented, improving their durability.

By displaying the amount and direction of bending of the nozzle on the bend indicator, the direction and amount to adjust the nozzle position can be easily grasped, and the alignment status of the nozzle can also be confirmed remotely. You will be able to do this.

Furthermore, since the nozzle position is automatically finely adjusted, it is possible to use molds without a locating ring, molds with a locating ring that is smaller in diameter than the locating hole of the injection molding machine, or molds where the nozzle receiver is already unevenly worn. Even when using a mold, there is no need to manually fine-tune the mold mounting position. Therefore,
It also becomes easy to construct a fully automatic mold exchange system.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the centering device used in the nozzle centering method according to the present invention, and FIG. 2 shows a side view of the nozzle and bend indicator of an injection molding machine, and FIG. 3 is a side view of essential parts of an injection molding machine showing an embodiment of the nozzle centering device according to the present invention, and FIG. 4 is a partially cutaway view showing the centering device together with a control block. FIG. 5 is a side view of the main parts of an injection molding machine equipped with a conventional nozzle alignment device, FIG. 6 is an enlarged sectional view showing the correct alignment of the nozzle, and FIG. 7 is a cutaway plan view. , is an enlarged cross-sectional view showing a state where the nozzle is eccentric. 1... Injection device, 2... Slide base, 3...
...Shift cylinder, 4...Screw cylinder, 5
... Nozzle, 7 ... Mold, 10 ... Sprue bush (nozzle receiving part), 10a ... Nozzle receiving surface,
11, 12... Adjustment bolt, 20 ₁ , 20
₂ , 20 ₃ , 20 ₄ ... strain gauge, 22 ... bending detector, 25 ... bending indicator, 26 ₁ , 26 ₂ ,
26 ₃ , 26 ₄ ...indication lamp, 27a, 27b...
... Display meter, 30 ... Base plate, 31 ... Guide rail, 33 ... Adjustment shaft, 34 ... Motor,
35...Horizontal position adjustment device, 36, 37...
Jacket bolt, 40, 41...Adjustment shaft, 46,
47...Motor, 48...Vertical position adjustment device, 50...Control device.

Claims (1)

[Claims] 1 The nozzle at the tip of the screw cylinder is pressed against the nozzle receiving part of the mold, and at this time, a minute bend of the nozzle itself in the axial direction of the nozzle caused by misalignment between the two is detected. A method for aligning a nozzle in an injection molding machine, comprising moving the nozzle in a direction that reduces bending. 2. A method for aligning a nozzle in an injection molding machine according to claim 1, wherein the bending of the nozzle in the axial direction is detected based on a difference in the amount of strain at a plurality of locations on the outer periphery of the nozzle. 3. A bending detector that detects the bending of the nozzle in the axial direction when the nozzle at the tip of the screw cylinder is pressed against the nozzle receiving part of the mold, and the bending of the nozzle detected by the bending detector. A device for centering a nozzle in an injection molding machine, comprising: a bending indicator that displays the amount and bending direction; 4. The bending detector comprises a strain gauge attached to the nozzle at the tip of the screw cylinder or a plurality of locations on the outer circumferential surface in the vicinity thereof, and the bending indicator detects the amount of strain detected by the strain gauge. 4. The nozzle centering device for an injection molding machine according to claim 3, wherein the nozzle bending amount and bending direction are displayed based on the difference. 5. A vertical position adjustment device and a horizontal position adjustment device that can adjust the position of the nozzle at the tip of the screw cylinder in the vertical and horizontal directions, respectively, and when the nozzle is pressed against the nozzle receiver of the mold, the nozzle a bend detector that detects a bend in the axial direction that occurs; and a bend detector that operates the vertical position adjustment device and the horizontal position adjustment device according to the amount and direction of bend of the nozzle detected by the bend detector. A nozzle alignment device for an injection molding machine, comprising: a control device;