JP4033686B2 - Screw tooth profile processing method for screw rotor for fluid machine of spiral screw - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screw tooth processing method and a processing apparatus for a screw rotor used in a screw fluid machine such as a screw compressor or a screw pump.
[0002]
[Prior art]
The processing of the screw tooth profile of a pair of male and female screw rotors used in screw fluid machines such as screw compressors and screw pumps is performed by cutting a cutter blade 1a shaped so as to obtain a desired tooth profile as shown in FIG. This is done by cutting or grinding the workpiece with a single-cut cutter 1 (hereinafter referred to as “single cutter”) disposed on the outer periphery of the body 1b, or a grindstone shaped so as to obtain a desired tooth profile.
[0003]
In recent years, in order to improve the performance of screw compressors and screw pumps, many researches and developments have been made on the shape of the screw tooth profile, and the shape of the screw tooth profile covers various types such as a combination of complex curves. For this reason, advanced techniques are required for the processing method of the screw tooth profile, and there is an increasing demand for a multifunctional processing machine for the processing apparatus.
[0004]
For example, a rotor used in a spiral screw fluid machine having a cross-sectional shape perpendicular to the axis shown in FIG. 12 consisting of a Quimby curve and an Archimedes curve has a tooth groove continuously formed with a predetermined twist angle α ′, and Since the side surface of the tooth that defines this tooth gap has a shape inclined by θ ′, it has a shape as shown in FIG. The curve portion in the middle a) has a special shape that is greatly recessed from the line X passing through the rotation axis 7 toward the inner peripheral side (Japanese Patent Laid-Open No. 11-270479).
Therefore, this tooth profile cannot be processed by a general-purpose processing apparatus used for processing a normal screw rotor, and the rotary shaft 3 of the cutter 1 is inclined by the angle α in the vertical direction according to the torsion angle α ′ of the tooth gap. Therefore, a dedicated processing apparatus having a special structure for processing by tilting the tilt angle θ in the horizontal direction in accordance with the tilt angle θ ′ formed on the side surface of the tooth space is required.
[0005]
An example will be described as a method of processing the tooth profile of the spiral screw rotor.
FIG. 11 is a schematic external view of a milling machine 60 for processing a spiral screw rotor. The milling machine 60 includes a cutter rotating shaft 3 that rotates a single cutter 1 formed so as to obtain a desired screw tooth profile, and a workpiece rotating shaft 9 that rotates a mounted workpiece 6.
As shown in FIG. 14, the single cutter 1 has a plurality of cutter blades 1 a attached to the outer periphery of the cutter body 1 b, and the workpiece 6 is cut by rotating the single cutter 1.
[0006]
The machining state of the single cutter 1 and the workpiece 6 will be described in detail with reference to FIG.
First, the rotation center Oc ′ of the single cutter 1 is moved along the line 55 to the work 6 side by an amount corresponding to the cut amount. Next, the single cutter 1 is rotated about the axis 54 of the cutter rotating shaft 3. At this time, the workpiece 6 is moved from the left side to the right side in the drawing while rotating around the rotation axis 7 of the workpiece. The speed of movement and rotation of the workpiece 6 is determined from the lead angle of the desired screw tooth profile, the cutting speed at the time of processing, and the like.
Thus, a desired screw tooth-shaped groove portion can be processed.
In particular, when the screw tooth profile of the spiral screw rotor 15 is machined, the shaft has a right-angle cross-sectional shape having a quinby curve portion that is greatly recessed from the line X passing through the rotation axis 7 of the rotor, which is the workpiece 6, to the inner peripheral side. Since the tooth shape must be processed, as shown in the plan view of FIG. 9, the rotation axis 53 of the single cutter 1 is inclined in the horizontal direction by the inclination angle θ, and the moving direction 55 of the rotation center Oc ′ of the single cutter 1 is set as the workpiece 6. It is necessary to provide a cutting angle inclined by an angle θ with respect to the direction perpendicular to the rotational axis 7 of the shaft.
[0007]
[Problems to be solved by the invention]
As described above, when machining a tooth profile with a cross-section perpendicular to the axis having a Quimby curve, it is necessary to provide a cutting angle θ to the single cutter 1, but such a cutting machine is used for a general-purpose milling machine or the like. Since a configuration for providing an angle is not provided, when forming a complicated tooth profile like the spiral screw rotor 15, a processing device such as a general-purpose milling machine cannot be used. It was necessary to use a special processing device with a special structure for adjusting the cutting angle.
As a result, an expensive dedicated milling machine with a special structure has to be introduced, and equipment costs for that, as well as a large amount of remodeling cost to incorporate the above-mentioned special structure into a general-purpose milling machine currently owned In addition to the general-purpose milling machine for processing a normal screw rotor, there is a waste of possessing this dedicated milling machine.
[0008]
In addition, it is a cause of problems such as an extra work for accurately adjusting the cutting angle of the cutter blade 1 and a decrease in processing accuracy due to a decrease in rigidity of the processing apparatus.
Furthermore, if all screw rotors, including ordinary screw rotors, are machined using this dedicated milling machine, the capital investment must be recovered and it is expensive even though it is a normal screw rotor. End up.
[0009]
Therefore, the present invention provides an inexpensive general-purpose processing device that does not introduce an expensive dedicated processing device having a special structure or makes a special modification to the general-purpose processing device. to provide a processing method capable of processing the tooth row data.
[0010]
[Means for solving problems]
In order to achieve the above object, a screw tooth profile machining method for a screw rotor for a spiral screw fluid machine according to the present invention includes a blade rotation shaft (cutter rotation shaft 3) for rotating a blade (cutter 1) and a workpiece for rotating a workpiece 6. A rotary shaft 9, and the blade 1 is moved toward the workpiece 6 while rotating according to the amount of cut with respect to the workpiece 6, and the workpiece 6 is rotated along the rotation axis 7 of the workpiece. Oite the screw tooth profile machined how the screw rotors to process the tooth profile of the desired twisted shape so moved,
The blade rotating shaft 3 having a single blade 1 shaped so as to obtain a desired tooth profile is inclined at an inclination angle α corresponding to the torsion angle α ′ of the tooth profile formed on the workpiece 6, and the blade tool The moving direction 5 of the rotation center Oc of 1 is perpendicular to the rotation axis 7 of the workpiece 6, and the rotation axis 7 of the workpiece 6 is moved 5 of the rotation center Oc of the blade 1 disposed in a position that does not overlap with the extension line, axis-perpendicular cross section and forming a tooth with a Quimby curve elaborate gouging on the inner peripheral side from a line passing through the rotation axis of the rotor (claim 1 ).
[0011]
The processing apparatus for realizing the above-described method includes, for example, a spacer 2 that can adjust the relative position between the rotation axis 7 of the workpiece 6 and the extension line in the moving direction 5 of the rotation center Oc of the blade 1. And adjusting means such as pedestals 8 and 8 'can also be provided . In concrete terms, by such lifting the workpiece conveyor 11 for moving to rotate the workpiece 6 mounted for example, placed on the pedestal 8, the extension line of the movement direction 5 of the rotational center Oc of the cutting tool 1, The workpiece 6 may be disposed below the rotation axis 7 of the workpiece 6 (Claim 2 ), and the extension line 5 of the rotation center Oc of the cutting tool 1 does not overlap the rotation axis 7 of the workpiece 6. The moving direction 5 of the rotation center Oc of the blade 1 is inclined (Claim 3 ). According to this method, the screw tooth profile of the rotor used in the spiral screw fluid machine having a quinby curve a that is pierced from the line X passing through the rotary shaft core 7 in the cross section perpendicular to the axis of the screw rotor shown in FIG. Without using an expensive dedicated processing device, and without incorporating a special structure into the general-purpose processing device, it can be processed using this with a slight change to the general-purpose processing device, There is no expensive introduction cost for introducing a dedicated processing device, no equipment cost for applying a special structure to the processing device, and no reduction in processing accuracy. Further, normal screw rotor processing can also be performed as usual.
[0012]
Moreover, the cutter 1 may be a single cutter 1 in which a cutter blade 1a shaped into a shape capable of forming a desired tooth profile on the workpiece 6 is disposed on the outer periphery of the cutter body 1b (Claim 4 ). It is good also as a grindstone shape | molded in the shape which can form a desired tooth profile in the said workpiece | work 6. (Claim 5 ).
[0013]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment will be described with reference to FIGS.
FIG. 1 is a view showing the positional relationship between the single cutter 1 and the workpiece 6 when the spiral screw rotor 15 is processed by the processing method of the present invention.
In FIG. 1, the shaft core 4 of the cutter rotating shaft 3 is inclined at an angle α with respect to the rotating shaft core 7 of the workpiece 6 corresponding to the formation direction of the tooth groove having a predetermined twist angle. A single cutter 1 and a spacer 2 are attached to 3. The cutter rotation center Oc of the single cutter 1 is offset by L in the right direction in FIG. 1 with respect to the cutter rotation center Oc ′ when the spacer 2 is provided without the spacer 2 since the spacer 2 is provided on the cutter rotation shaft 3. is doing. Therefore, the extension line in the moving direction 5 of the rotation center Oc of the cutter passes through a position shifted by a predetermined distance (Lsinα · cosα) below the rotation axis 7 of the workpiece 6.
[0014]
The processing procedure for the tooth profile of the screw rotor is as follows.
In FIG. 2, first, the single cutter 1 offset in the right direction along the cutter rotation shaft 4 is moved to the workpiece 6 side in the direction orthogonal to the rotation axis 7 of the workpiece 6 by an amount corresponding to the cut amount. Thereafter, the single cutter 1 is rotated by the cutter rotating shaft 3. At that time, the workpiece 6 stands by at the machining start position on the rotation axis 7 of the workpiece axis and on the left side of the single cutter 1.
Next, the workpiece 6 is moved from the left side to the right side in the drawing along the rotation axis 7 while rotating the workpiece 6 around the rotation axis 7.
When the workpiece 6 reaches the machining end position, the single cutter 1 is once separated from the workpiece 6, and the workpiece 6 is returned to the left side along the workpiece axis 7 to the machining start position.
[0015]
Next, the single cutter 1 is fed to the workpiece 6 side in the direction orthogonal to the rotation axis 7 of the workpiece 6 according to the cut amount, and then the single cutter 1 is rotated by the cutter rotation shaft 3.
Next, the work 6 is moved from the left side to the right side in the drawing along the rotation axis 7 while rotating the workpiece 6 around the rotation axis 7.
When the workpiece 6 reaches the machining end position, the single cutter 1 is once separated from the workpiece 6, and the workpiece 6 is returned to the left side along the workpiece axis 7 to the machining start position.
By repeating the above operation until a desired tooth profile is obtained, the groove portion of the screw tooth profile is processed.
[0016]
By offsetting the cutter rotation center Oc, even if the single cutter 1 is moved toward the workpiece 6 according to the cut amount, the rotation axis 7 of the workpiece 6 is on the extension line of the movement direction 5 of the cutter rotation center Oc. Since it is not arranged, the rotary shaft 3 of the cutter 1 is inclined in the horizontal direction in the shape of a shape that is greatly recessed from the center line of the outer diameter of the rotor to the inner peripheral side as shown by the Quimby curve a shown in FIG. As a result, a general-purpose milling machine can be used without using an expensive dedicated milling machine having a special structure to which a special configuration for inclining the rotation shaft 3 of the cutter 1 in the horizontal direction is added.
[0017]
Next, a second embodiment will be described.
In the second embodiment, in FIG. 6, the base 8 is sandwiched under the work conveyor 11 of the milling machine 10, so that the height of the rotation axis 7 of the work is extended in the moving direction 5 of the rotation center Oc of the cutter. In FIG. Thereby, the extension line | wire of the moving direction 5 of the rotation center Oc of the single cutter 1 can be made below the workpiece | work rotation axis 7 as shown in FIG.
The machining of the screw tooth profile on the milling machine 10 is performed by changing the position of the workpiece 6 in the height direction, that is, the height of the rotation axis 7 of the workpiece, and the extension line in the moving direction 5 of the rotation center Oc of the cutter and the rotation of the workpiece. Since the difference in height is given to the arrangement position of the shaft core 7, the description is omitted because it is the same as the first embodiment.
[0018]
Thus, as in the first embodiment, even when the single cutter 1 is sent to the workpiece 6 side according to the cut amount, the cutter rotation center Oc does not face the rotation axis 7 of the workpiece 6, so that it is shown in FIG. The processing of the tooth profile having a cross-sectional shape perpendicular to the axis having the quinby curve portion a having a shape that is greatly dented from the line X (see FIG. 13) passing through the rotation center 7 of the rotor 6 to the inner peripheral side as shown in the cubby curve a. It can be carried out with an inexpensive general-purpose milling machine without using an expensive dedicated milling machine having a special structure.
[0019]
Next, a third embodiment will be described.
In the third embodiment, in FIG. 7, a pedestal 8 ′ for inclining this is provided below the cutter conveyor 12 of the milling machine 10 ′, and an extension line in the moving direction of the rotation center Oc of the cutter is inclined, In addition, the rotation axis 7 of the workpiece 6 is arranged.
Since the machining in this case is the same as that of the first embodiment except that the cutter feed shaft 5 is inclined so that the cutter rotation center Oc advances toward the lower part of the rotation axis 7 of the workpiece, an explanation will be given. Omitted.
[0020]
Thereby, even if the rotation center Oc of the single cutter 1 is moved to the workpiece 6 side, the extension line in the moving direction 5 of the cutter rotation center Oc is at a position where it does not overlap with the workpiece rotation axis 7. The tooth profile having a cross section perpendicular to the line X passing through the rotor axis 7 of the rotor as shown by the cubby curve a is processed in the horizontal direction with respect to the axis 4 of the cutter axis 3. It can be performed without tilting, and can be performed with a general-purpose milling machine without using an expensive dedicated milling machine having a special structure for adjusting this angle.
In the above embodiment, the rotation center Oc of the single cutter 1 has been described as moving in the horizontal direction. However, it may be configured to move in the vertical direction. In this case, the inclination angle α of the cutter rotating shaft 3 is given by inclining the cutter rotating shaft 3 in the horizontal direction.
Further, in this embodiment, the pedestal 8 ′ is tilted so that the traveling direction of the cutter feed shaft 5 advances toward the lower side of the work shaft 7. However, the tilt of the pedestal 8 ′ is set so that the traveling direction of the cutter feed shaft 5 is the work axis. You may make it advance toward 7 upwards.
[0021]
As another embodiment, a desired tooth profile can be obtained for the single cutter 1 in which a cutter blade 1a shaped so as to obtain a desired tooth profile is arranged on the outer periphery of the cutter body 1b as compared with the first to third embodiments. It is possible to replace the milling machine with a grinding machine by replacing it with a grindstone shaped as described above.
The processing in that case is the same as that in the first embodiment except that the single cutter 1 is replaced with a grindstone with respect to the processing in the first to third embodiments, and a description thereof will be omitted.
[0022]
In the above-described embodiment, the processing using the milling machine and the grinding machine is described. However, the present invention can be changed not only in the milling machine and the grinding machine but also in other processing apparatuses without changing the gist of the present invention.
[0023]
【The invention's effect】
As described above, according to the present invention, a cutter rotating shaft that rotates a single cutter in which a cutter blade shaped so as to obtain a desired tooth profile is disposed on the outer periphery of the cutter body, and a workpiece rotating shaft that rotates a workpiece. And moving the single cutter toward the workpiece while rotating the single cutter according to the cut amount with respect to the workpiece, and moving the screw rotor along the rotation axis of the workpiece while rotating the workpiece. When processing into a twisted screw tooth profile, the blade rotation axis is inclined according to the torsion angle of the tooth profile formed on the workpiece, and the movement direction of the rotation center of the blade tool is relative to the rotation axis of the workpiece. The rotation axis of the workpiece is arranged at a position that does not overlap with the extension line in the movement direction of the rotation center of the cutting tool. Use an expensive dedicated milling machine with a special structure for the screw teeth of a screw rotor used in a spiral screw fluid machine that has a Quimby curve that digs inward from the line passing through the axis of rotation of the workpiece in a cross-sectional shape perpendicular to the axis. It can be processed with an inexpensive general-purpose milling machine. For this reason, there is no introduction cost for introducing an expensive dedicated milling machine, equipment cost for applying a special structure to a general-purpose milling machine, and no reduction in machining accuracy.
In addition to processing special screw tooth profiles such as spiral screw rotors, normal screw tooth profiles can be processed as usual with a general-purpose milling machine, and the screw tooth profile of the screw rotor is a single screw, 2 Even a long thread or other multi-thread can be processed by the processing method and processing apparatus of the present invention. It is also applicable to grinding by rotating a grindstone shaped to obtain the desired tooth profile instead of a single cutter with a cutter blade shaped to obtain the desired tooth profile on the outer periphery of the cutter body. Therefore, it is not necessary to provide an expensive grinder with a special structure, and it can be processed with a general-purpose grinder. Therefore, there is no equipment cost for applying a special structure to the general-purpose grinding machine, and the processing accuracy is not lowered.
[Brief description of the drawings]
FIG. 1 is a front view of a single cutter and a workpiece of a milling machine according to a first embodiment of the present invention as viewed from the single cutter side.
FIG. 2 is a plan view of a single cutter and a workpiece of the milling machine according to the first embodiment of the present invention.
FIG. 3 is a side view of a single cutter and a workpiece of the milling machine according to the first embodiment of the present invention.
FIG. 4 is a front view of a single cutter and a workpiece of a milling machine according to a second embodiment of the present invention as viewed from the single cutter side.
FIG. 5 is a plan view of a single cutter and a workpiece of a milling machine according to a second embodiment of the present invention.
FIG. 6 is a schematic view of a milling machine according to a second embodiment of the present invention.
FIG. 7 is a schematic view of a milling machine according to a third embodiment of the present invention.
FIG. 8 is a front view of a conventional milling machine as seen from the single cutter side of a single cutter and a workpiece.
FIG. 9 is a plan view of a single cutter and a workpiece of a conventional milling machine.
FIG. 10 is a side view of a single cutter and a workpiece of a conventional milling machine.
FIG. 11 is a schematic view of a conventional milling machine.
FIG. 12 is an external view of a spiral screw rotor.
FIG. 13 is a diagram showing a cross-sectional shape perpendicular to the axis of the tooth profile of the spiral screw rotor.
FIG. 14 is a front view and a plan view showing a single cutter.
[Explanation of symbols]
1 Single cutter (blade)
DESCRIPTION OF SYMBOLS 1a Cutter blade 1b Cutter body 2 Spacer 3 Cutter (blade) rotating shaft 4 Axle [of cutter (blade) rotating shaft]
5 A line indicating the moving direction of the cutter (cutting tool) rotation center Oc 6 Work piece 7 Axis of rotation of the work 8, 8 'Pedestal 9 Work rotation axis 10 Milling machine 10' according to the second embodiment of the present invention Milling machine 11 according to the third embodiment Work conveyor 12 Cutter conveyor 15 Spiral screw rotor 16 Reference example 50 of spiral screw tooth profile Conventional processing device (milling machine)
53 Conventional cutter rotating shaft 54 Axle (conventional cutter rotating shaft)
55 Line indicating the moving direction of the cutter (cutting tool) rotation center Oc '(conventional)
Oc Cutter rotation center θ Tilt angle of cutter rotation axis (horizontal direction)
θ 'Inclination angle of rotor tooth groove side α Inclination angle of cutter rotation axis (vertical direction)
α 'Torsion angle X-ray of rotor tooth groove (line passing through the rotation axis of the workpiece)

Claims (5)

A blade rotation axis for rotating the blade and a workpiece rotation axis for rotating the workpiece, and moving the blade toward the workpiece while rotating the blade according to a cutting amount with respect to the workpiece, while rotating the workpiece In the screw tooth profile processing method of the screw rotor, which is moved along the rotation axis of the work shaft and processed into a desired twisted tooth profile,
The blade rotation axis provided with a single cutting tool shaped so as to obtain a desired tooth profile is inclined according to the torsion angle of the tooth profile formed on the workpiece, and the moving direction of the rotation center of the blade tool is The cross-sectional shape perpendicular to the axis of the rotor is such that the cross-sectional shape of the rotor is perpendicular to the rotational axis of the workpiece, and the rotational axis of the workpiece does not overlap the extension line of the moving direction of the rotation center of the blade . A screw tooth profile processing method for a screw rotor for a spiral screw fluid machine , characterized in that a tooth profile having a quinby curve is formed inward from a line passing through a rotation axis . Screw tooth profile processing method according to claim 1 spy Lucky tangential screw fluid machine for screw rotor, wherein placing the extension line in the moving direction of the center of rotation of the cutting tool under the rotational axis of the workpiece. The spiral screw fluid machine according to claim 1 or 2 , wherein a traveling direction extension line of a rotation center of the blade tool is inclined in a traveling direction of the rotation center of the blade tool so as not to overlap a rotation axis of the workpiece. Screw tooth profile processing method for screw rotors. The spiral screw fluid machine according to any one of claims 1 to 3 , wherein the cutting tool is a single cutter in which a cutter blade shaped into a shape capable of forming a desired tooth profile on the workpiece is disposed on the outer periphery of the cutter body. Screw tooth profile processing method for screw rotors. The screw tooth profile processing method for a screw rotor for a spiral screw fluid machine according to any one of claims 1 to 3 , wherein the cutting tool is a grindstone shaped into a shape capable of forming a desired tooth profile on the workpiece.

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