JP2521557Y2 - Drive device for twin screw extruder - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive unit for a twin-screw extruder that makes the meshing phase difference of the screw shafts of the twin-screw extruder as uniform as possible.

[0002]

2. Description of the Related Art Generally, a drive unit for a twin-screw extruder has a narrow screw distance and transmits a large torque.
It is required that the phase difference between the shafts, that is, the mutual difference between the axial displacement and the torsion angle is small. FIG. 3 shows a drive device for a conventional twin-screw extruder, in which a first torque shaft 1 is directly driven by an output gear 3 in a first reduction stage from a prime mover, and a second screw shaft 2 is
A second torque separating gear 7 that is torque-separated by a first torque separating gear 5 that meshes with a first gear 4 fixed to the first screw shaft 1 and meshes with a second torque separating gear 7 that is fixed to a torque separating shaft 6.
It is driven by the gear 8. The meshing center distance of the screw between the first screw shaft 1 and the second screw shaft 2 is E ₁ ,
Reference numeral ₂ denotes the center distance between the second screw shaft 2 and the torque separating shaft 6.

As described above, although the torque transmitted to the screw shaft is large, the distance E ₁ between the screw shafts is small, so that the first screw shaft diameter d ₁ and the second screw shaft 2 are fixed. The outer diameter d ₂ of the two gear 8 also has to be limited. In order to increase the load capacity of the second torque separation gear 7 and the second gear 8 that meshes with the second torque separation gear 7, it is necessary to increase the center distance E ₂ between the second screw shaft 2 and the torque separation shaft 6. As a result, a large difference occurs in the torsional rigidity of the drive shaft system between the first screw shaft 1 and the second screw shaft 2, and when the extruder is loaded, there is a difference in the torsional displacement amount of the two screws, which causes a difference in screw displacement. There is a risk that the phase of the meshing will shift and meshing interference will occur.

In order to solve the above problems, the following drive device shown in FIG. 4 has been proposed. That is, the torque separating shaft 6'and the second torque separating gear 7'are divided into structures, the second torque separating gear 7'is hollow, and both sides of the gear are supported by the bearings 12, and the shaft end of the torque separating shaft 6'is formed. Section, the hollow shaft of the second torque separating gear 7'and the spline 6 '
a, 7'a, and the torque separating shaft 6'is provided with a shaft portion having a small diameter and a long diameter so that the torsional rigidity of the drive transmission system of the second screw shaft is equal to the torsional rigidity of the first screw shaft. When the screws are loaded on the screw, the torsional displacements of the shafts are made the same to eliminate the relative phase difference between the two screws.

[0005]

As described above, the torque separating shaft 6 is provided with a torsion shaft portion having a rigidity commensurate with the torsional rigidity of the first screw shaft 1, and the torsion angles of both screws when loaded on the screw. The problem of relative phase difference of
The torque separating shaft 6'and the second torque separating gear 7'shown in FIG.
Are connected to each other by a spline, and the second torque separating gear 7 ′ has a structure in which both sides are independently supported by the bearing 12. Since a gear that transmits a large torque like this drive mechanism usually uses a helical gear to reduce tooth deformation and smooth rotation, the bearing of the second torque separation gear 7'is provided. Although the thrust bearing 13 must be provided in the second torque separating gear 7'as described above, the structure around the second torque separating gear 7'and the second gear 8 of the second screw meshing with the second torque separating gear 7'is very cramped. Gear 7 '
Although a thin cylindrical roller bearing or a needle bearing can be used in the radial direction as a bearing for supporting the bearing, it was difficult to provide the thrust bearing 13 having sufficient strength in the thrust direction.

According to the present invention, the hollow shaft of the second torque separation gear on the side of the first torque separation gear is extended so that the end surface of the hollow shaft contacts the shoulder of the torque separation shaft at a position close to the first torque separation gear. The thrust bearing 13 shown in FIG. 4 is intended to provide a drive device that does not use the thrust bearing 13 and to provide a drive device for a twin-screw extruder that can solve the above-mentioned conventional problems.

[0007]

Therefore, according to the present invention, there is provided a first screw shaft integral with a first gear connected to a drive source, a first torque separating gear meshing with the first gear, and a first torque. The first screw shaft and the second screw are composed of a torque separation shaft that connects the separation gear and the second torque separation gear, and a second gear that meshes with the second torque separation gear and is integral with the second screw shaft. A drive device for a co-rotating twin-screw extruder in which a shaft and a torque separating shaft are arranged in parallel with each other,
The torque separating gear shaft is hollow and independently supported by bearings on both sides. The screw side of the hollow shaft is connected to the torque separating shaft by an involute spline, and the end of the hollow shaft on the first torque separating gear side is the torque separating shaft. The tooth contact failure between the second torque separation gear and the second gear on the screw shaft due to an assembly and machining error is covered by contacting the shoulder of the second gear, and at the same time, it is caused by the meshing of the second torque separation gear and the second gear. and axial thrust, the first torque separation gear and the first gear
Both helical gears, made of so as to offset the axial thrust generated by meshing of its is for a means for this problem solution.

[0008]

The axial thrust generated when the power is transmitted from the second torque separating gear to the second gear on the second screw shaft is
At the end of the extension cylinder integrated with the second torque separating gear, the stepping shoulder of the torque separating shaft is pressed to push the torque separating shaft in the direction opposite to the screw, but the divided torque is transferred from the first gear to the first torque separating gear. If the helical angle of the gears is determined so that the thrust force received by the first torque separation gears when transmitted is in the screw direction, the thrust forces acting on the torque separation shafts by the two sets of gears cancel each other out. A bearing that supports the torque separation shaft is sufficient if it has a thrust receiving capacity with a small capacity. The second torque separating gear is independently supported by the radial bearing, the parallelism between the gear and the second screw shaft is maintained, and the meshing of the gears can be normally maintained. On the other hand, the accuracy error and the assembly error of the parts around the torque separation shaft can be covered by the spline of the coupling portion because the second torque separation gear and the torque separation shaft are separate bodies.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments of the drawings. FIG. 1 is a sectional view of a drive unit of a twin-screw extruder showing an embodiment of the present invention, and FIG. 2 is a detailed view around a torque separating shaft in FIG. It is sectional drawing shown. In FIG. 1, 1 is a first screw shaft, 2 is a second screw shaft, 3 is an output gear, and 4 is a first screw shaft.
Gears, 5 is a first torque separating gear, 8 is a second gear,
These are the same as the conventional ones in FIG. In FIG. 1 showing an embodiment of the present invention, the difference from the conventional FIG. 3 will be described. The first screw shaft 1 is directly driven by the output gear 3 of the first reduction stage driven by the prime mover, and the second screw is driven. The shaft 2 is a first gear shaft 4 coaxial with the first screw shaft 1, a torque separation shaft 6'that is torque-separated into a first torque separation gear 5 that meshes with the first gear shaft 4, and a second torque separation gear 9
It is driven by the separation torque transmitted to the second gear 8 on the second screw shaft 2 via.

The torque separating gear 6'includes a first unit integrated with the first gear.
It is supported by bearings 11, 11 arranged on both sides of the torque separation gear 5. The second torque separating gear 9 is attached to the spline 6'a at the extended shaft end of the torque separating shaft 6 '.
The inner spline 9a is fitted and coupled, and the second torque separation gear 9 has radial bearings 12 and 12 at both ends (since there is little room in the installation location, an elongated cylindrical roller bearing or a needle bearing that directly receives the shaft without inner races). And is in contact with the shoulder 6'b of the torque separating shaft 6'at the end 9b of the tubular extension shaft.

Next, the operation will be described with reference to FIG.
Power (or torque) from the gear 4 to the first torque separating gear 5
Is transmitted, the rotation direction of the first gear 4 is the same as the rotation direction of the first screw shaft 1 indicated by the arrow.
When the helical angle between the gear 4 and the first torque separating gear 5 is as shown in the figure, the arrow F ₁ is attached to the first torque separating gear 5.
Axial thrust force is applied in the direction shown in.

Next, the torque separation shaft 6'rotates in the direction of the arrow, and the second torque separation gear 9 also rotates in the same direction. In this way, when the helical angles of the second torque separation gear 9 and the second gear 8 are in the directions shown, the second torque separation gear 9 and the second
When power is transmitted to the gear 8, the second torque separating gear 9
Receives a thrust force in the direction of arrow F ₂ in the figure. The aforementioned thrust forces F ₁ and F ₂ are forces in opposite directions, and the shaft end 9b of the second torque separating gear 9 is the shoulder 6'of the torque separating shaft 6 '.
Since it is in contact with b, the thrust force F ₂ received by the second torque separation gear 9 is transmitted to the torque separation shaft 6 ′, and the thrust forces F ₁ and F ₂ are offset on this torque separation shaft 6 ′. Therefore, the bearing 11 that supports the torque separation shaft 6'is
Only a small thrust force is required. Moreover, since the frame supporting the bearing 11 of the torque separating shaft 6'has a sufficient space, the first torque separating gear 5 has a sufficient load capacity with respect to the combined load of the radial force and the thrust force received during power transmission. The bearing can be selected.

The torque separating shaft 6'and the second torque separating gear 9
Are supported by bearings 11 and 11 and bearings 12 and 12 independently of each other to maintain the axial position, and the connection between the two is in contact with the splines 6'a and 9a in the axial direction. Although there is no play, some play (deviation) is allowed in the eccentricity and inclination of the shaft and the shaft, so there is a precision error in the parts,
It can cover assembly error.

[0014]

As described in detail above, according to the present invention, the thrust generated by the helical gear of the second screw shaft drive system can be offset on the torque separating shaft, so that no special thrust bearing is required for thrust reception. .
Further, since the second torque separation gear and the torque separation shaft are spline-coupled to each other, errors in machining and assembling parts can be absorbed, so that the durability of the functional part is improved and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a driving device of a twin-screw extruder according to an embodiment of the present invention.

FIG. 2 is a detailed cross-sectional view showing an engaged state of a torque separation shaft and a second torque separation gear in FIG.

FIG. 3 is a cross-sectional view of a drive device of a conventional twin-screw extruder.

FIG. 4 is a detailed cross-sectional view showing an engaged state of a torque separation shaft and a second torque separation gear, which is different from the conventional case of FIG.

[Explanation of symbols]

 1 1st screw shaft 2 2nd screw shaft 3 output gear 4 1st gear 5 1st torque separation gear 6'torque separation shaft 6'a torque separation shaft spline 8 2nd gear 9 second torque separation gear 9a inner spline 12 bearing B 6'b shoulder 9b end

Claims (1)

(57) [Scope of utility model registration request] 1. A first unit integrated with a first gear connected to a drive source.
A screw shaft; a first torque separation gear that meshes with the first gear; a torque separation shaft that connects the first torque separation gear and the second torque separation gear; and a first torque separation gear that meshes with the second torque separation gear. A drive device for a co-rotating twin-screw extruder, comprising two screw shafts and a second gear integrated with each other, wherein the first screw shaft, the second screw shaft, and the torque separating shaft are arranged in parallel with each other. The torque separating gear shaft is hollow and independently supported by bearings on both sides. The screw side of the hollow shaft is connected to the torque separating shaft by an involute spline, and the end of the hollow shaft on the first torque separating gear side is the torque separating shaft. The second torque separation gear and the second gear on the screw shaft can be prevented from coming into contact with the shoulder of the second gear due to an error in assembly and processing, and at the same time, the second torque separation gear and the second gear can be meshed to each other. That the axial thrust, and a first torque separate gear to first gear and both helical gears, biaxial extruder driving apparatus is characterized in that so as to offset the axial thrust generated by meshing of their .