JPH06218729A - Plastic pelletizer - Google Patents

Abstract

PURPOSE:To surely and accurately set a close contact dimension between a die face and a cutter and always keep them in the close contact state when a plastic in a melt state extruded out of a die is cut by the cutter to be pelletized by rotating the cutter in close contact with the die face. CONSTITUTION:The contact face of slide rings 7, 8 is disposed in proximity to the close contact position of a cutter 5 and a die face 2a. Therefore, the close contact dimension or distance between the cutter 5 and the die face 2a never varies even if a die 2 expands by heating. A pressing means 6, e.g. a spring, for pressing a cutter holder 4 toward the die 2 is provided between a cutter drive shaft 3 and the cutter holder 4. A spacer 3h is provided between a spring bearing 3a and the pressing means (spring) 6. By changing the thickness of the spacer 3h, the mounting dimension of the spring is changed. In this manner, a gap between the tip of the cutter and the die face can be kept very small, and the cutter is prevented from wearing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved plastic granulating apparatus in which the degree of proximity between a cutter and a die face in the plastic granulating apparatus is good.

[0002]

2. Description of the Related Art A plastic granulating apparatus extrudes plastic in a molten state from a die, rotates a cutter in contact with or in proximity to a die face, and cuts the extruded plastic with the cutter to granulate. The above-mentioned plastic granulating apparatus is known. As a device for providing a minute gap between the cutter and the die face, for example, Japanese Patent Publication No. 56-1248.
There is one shown in Japanese Patent Publication No. 9. As is the case with the embodiments of this application, the position for supporting the shaft that normally holds the cutter holder is to prevent the bearing from being heated and to be separated from the surface formed by the die face or the cutting edge of the cutter in the axial direction. Since they are in different positions, these parts (particularly the shaft for holding the holder) expands and contracts due to temperature changes due to heating and cooling, and as a result, the value of the minute gap changes. In the above-mentioned publication, this gap is adjusted by an adjusting means provided separately, but the adjustment requires detailed observation and repeated manual labor within a short time. On the other hand, a contact pressure between the cutter and the die face or a gap is continuously measured, and the value is fed back to obtain an appropriate value by a pneumatic cylinder, for example, Japanese Patent Publication No. 56-46966. . In such a device, the device becomes large-scale, the equipment cost is high, and maintenance is difficult. Further, for example, Japanese Patent Publication No. 56-12489 is known to press the cutter against the die face. However, when the cutter and the die face are brought into direct contact with each other, the tip of the cutter is originally sharp, and the contact area with the die face is small, so the contact pressure per unit area is large and the tip of the cutter is severely worn. Become. In addition, although there is little fear of wear when they are brought close to each other, it is difficult to adjust them to an optimum close dimension (for example, 0.01 mm) due to the influence of the above-mentioned temperature change and to always maintain the state.

[0003]

In the present invention,
It is an object of the present invention to provide an improved plastic granulating apparatus capable of reliably and accurately setting the size of the proximity and always maintaining the state.

[0004]

A plastic granulating apparatus 1 of the present invention will be described with reference to the drawings. Reference numeral 2 is a die, and a flat die face 2a is formed on the end surface thereof. On the other hand, the cutter drive shaft 3 is rotatably supported by passing through the die 2, and the cutter holder 4 is held by the cutter drive shaft 3. The cutter 5 is attached to the cutter holder 4. The die 2 is provided with a die-side slide ring 7, and the cutter holder 4 is provided with a cutter-side slide ring 8, and these slide rings 7 and 8 face each other so that they can contact and slide with each other. Composed. Further, the contact-sliding surface F and the die face 2a are arranged close to each other in the axial direction of the cutter drive shaft 3.

Further, the jig 10 is provided with an insertion hole 11 for inserting the cutter holder 4 and a jig side sliding ring 12, and when the cutter holder 4 is inserted into the insertion hole 11, the jig side is formed. The sliding ring 12 and the cutter-side sliding ring 8 are arranged so as to be in contact with each other.
The cutter 5 is configured to be fixed to the cutter holder 4 while being pressed against the end surface 10a formed in 0.

[0006]

By using the jig 10 having the structure described above,
The cutter 5 is attached to the cutter holder 4 in advance according to the procedure described above. When the cutter holder 4 with the cutter 5 thus adjusted is mounted on the actual machine (the shaft 3), the two sliding rings 7 and 8 come into contact with each other. In this state, the tip of the cutter 5 and the die face 2a
The proximity dimension (gap) S ₂ is very small (for example, 0.01 m
m). In addition, when the jig 10 is used to adjust the above-described configuration, the surface drawn by the rotation of the tip of the cutter 5 is within a certain plane for all the tips of the cutter, and the surface of the cutter drive shaft 3 is On the other hand, it is almost completely vertical. Therefore, when mounted on an actual machine, the state adjusted using the jig 10 is reproduced as it is. That is, if the die face 2a is installed perpendicularly to the axis of the cutter drive shaft 3,
The tip of the cutter of the face is completely parallel to the rotating surface, and therefore the absolute value of the gap is uniform and small at any position (for example, 0.01 m).
m) can be kept. The surface F and the die face 2a
Since the dimension L of the cutter driving shaft 3 in the axial direction is small, the change in S ₂ due to thermal expansion is also small.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. The plastic granulator 1 is connected to a known screw extruder P at its end by an adapter nozzle 20. P ₁ is a screw, P ₂ is a breaker plate, and P ₃ is an adapter plate. The resin passage in the adapter nozzle 20 communicates with an annular resin passage 2b provided in the die 2. The end of the resin passage 2b is opened as a die hole 2c in the die face 2a. The cutter drive shaft 3 is rotatably supported by a bearing 3a, and is combined with the cutter holder 4 by a female spline 4b on the cutter holder side and a male spline 3b on the shaft side. 9 is a motor,
The output shaft 9a and the cutter drive shaft 3 are connected by a coupling 9b. The cutter 5 is fastened to the cutter holder 4 with bolts 5a, and the mounting position of the cutter 5 is adjusted by accommodating the mounting holes at the time of fastening. Further, in this embodiment, since the contact surfaces of both the sliding rings 7 and 8 and the location where the cutter 5 and the die face 2a are in close proximity to each other, the cutter 5 and the die face may be expanded even when the die 2 is expanded by heating. There is no change in the proximity of 2a and thus the distance. Further, between the cutter drive shaft 3 and the cutter holder 4, a pressing means 6 for urging the cutter holder 4 in the direction of pressing the cutter holder 4 toward the die 2 side.
For example, a spring is interposed. S due to thermal expansion
The change of ₂ is that when the temperature difference due to the change over time is 30 ° C,
If the dimension L is 20 mm, the change of S ₂ is about 0.01 m
When m and dimension L are 50 mm, the change of S ₂ is 0.03 m
m. Therefore, the dimension L is preferably 50 mm or less, and more preferably 20 mm or less.

A male screw is formed at the tip 3e of the shaft 3, and a nut 3f is screwed into the male screw, and a spring seat 3g is attached and fixed to the shaft 3 by the nut 3f. Further, a spacer 3h is interposed between the spring seat 3g and the pressing means (spring) 6, and the attachment size of the spring is changed by changing the thickness of the spacer 3h.
That is, when the thickness of the spacer 3h is increased, the mounting dimension of the spring is small, and conversely, when the thickness of the spacer 3h is reduced, the mounting dimension of the spring is large. That is, the pressing force between the sliding rings 7 and 8 is adjusted by the pressing means (spring) 6. Alternatively, the seat 3g is also screwed into the outer periphery of the tip 3e, the screwing position is adjusted, and then locked by the nut 3f. Further, as the pressing means 6 for applying the pressing force between the two sliding rings 7 and 8, instead of the spring, a pressure fluid may be enclosed in the space containing the spring. In this case, the space is provided with a pressure seal, a well-known rotary valve is provided at the upper end of the shaft 3, and the pressure fluid is injected therein.

In the jig 10, the axial dimension S ₁ between the surface of the jig-side sliding ring 12 and the end surface 10a is determined by the cutter holder 4
Is set to be equal to the sum of the proximity dimension S ₂ and the dimension L of the tip of the cutter 5 and the die face 2a when the is mounted on an actual machine (plastic granulating apparatus 1). In order to satisfy such a condition, several adjusting plates 10b for holding the jig-side sliding ring 12 are prepared, and these are sequentially exchanged to satisfy the above-described condition by trial and error. It is assumed that a plurality of adjusting plates 10b having slightly different thicknesses are prepared in stages. 10c is a bolt for fixing the cutter holder 4 to the jig 10. At least the sliding rings 7 and 8 that slide at all times are made of ferro titanium,
A hard material having good wear resistance is desirable. Sliding ring 7,8
If the amount of friction is extremely small, the distance between the die face 2a and the cutting edge of the cutter 5 does not change during operation,
Further, since the blade edge of the cutter 5 has almost no friction, the situation does not change during operation.

The end surface 10a is a smooth surface having no unevenness and is manufactured so as to be completely perpendicular to the insertion hole 11 described above. The cutter holder 4 has an outer diameter 4a.
It is preferable to use an intermediate fit (JIS B 0401) where the dimensional tolerance of the jig 10 is small with respect to the insertion hole 11 on the jig 10 side or a clearance fit with a narrow tolerance range. When removed from the jig 10 and attached to the actual cutter drive shaft 3,
Similarly, it is preferable that the inner diameters 4c and 4d at both ends of the cutter holder 4 are intermediate fits with little play or clearance fits with a narrow tolerance range at the portions where the inner diameters 4c and 4d are fitted to the outer diameters 3c and 3d of the cutter shaft. The cutter shaft-side spline 3b and the cutter holder-side spline 4b mesh with each other in the middle of the two fitting portions. Absent. Cutter holder 4 described above
Between the outer diameter 4a and the inner diameters 4c and 4d at both ends, strictly maintain the parallelism of the axes with each other, and the inner diameters 4c and 4d.
Both need to be eccentric with respect to the outer diameter 4a.

[0011]

Since the plastic granulator of the present invention is constructed as described above, the gap between the tip of the cutter and the die face is kept small, the cutter is not worn, and granulation is ideal. And can be manufactured into good pellets. In addition, a jig can be used to accurately set the gap.

[Brief description of drawings]

1 is a vertical cross-sectional view of a plastic granulator.

FIG. 2 is a view on arrow A in FIG.

[Fig. 3] Vertical sectional view of the jig

[Explanation of symbols]

 1 Plastic Granulator 2 Die 2a Die Face 3 Cutter Drive Shaft 4 Cutter Holder 5 Cutter 6 Pressing Means 7 Die Side Sliding Ring 8 Cutter Side Sliding Ring 10 Jig 10a End Face 11 Insertion Port 12 Jig Side Sliding Ring

Claims (2)

[Claims] 1. A granulating apparatus in which plastic is extruded in a molten state from a die, a cutter is rotated in the vicinity of a die face, and the extruded plastic is cut and granulated by the cutter, A cutter holder to which the cutter is attached is held with respect to a cutter drive shaft, and the die and the cutter holder are configured to slide in contact between a die side slide ring and a cutter side slide ring, The plastic granulating apparatus, wherein the contact-sliding surface and the die face are close to each other in the axial direction of the cutter driving shaft. 2. A jig is provided for adjusting the proximity of the distance between the cutter and the die face when the cutter is attached to the cutter holder, and the jig has a jig side sliding ring. An insertion hole for inserting the cutter holder is provided, and the cutter side sliding ring of the inserted cutter holder and the jig side sliding ring are brought into contact with each other. The plastic granulating apparatus according to claim 1, wherein the cutter is fixed to the cutter holder by being pressed against the formed end surface.