JPH02235525A - Manufacture of screw rotor - Google Patents

Abstract

PURPOSE:To form a rotor having high accuracy by extruding a toothed stock having a linear tooth or a gentle spiral tooth and a core hole, applying a torque to both ends of the toothed stock, while obstructing the deformation of the core hole part with a mandrel, and imparting an angle of torsion to a final angle of torsion. CONSTITUTION:A die 1 for a first stage is formed by combining a male die 2 and a female die 3. As for the male die 2, a mandrel 4 is connected to the center with four pieces of arms 5, passage 6 communicates with a confluence chamber 7 and the mandrel 4 protrudes a little. The female die 3 has a center hole 8 and a radial tooth form groove 9, and on a base end face 3a side, the mandrel 4 goes into the center hole 8. A female die 34 is provided with a tooth form groove 9A having no torsion which extends radially from a center hole 8A. A toothed stock W1 in which a linear tooth 11A extended from a base part 10A is formed and a core hole 12A is opened in the center is obtained. A female die 3B is provided with a tooth groove part 9B having an angle of torsion alpha from the center hole 8B and a phase difference (e) exists on the inlet side and the outlet side. A toothed stock W2 in which a spiral tooth 11B of alpha1 from a base part 10B and a core hole 12B in the center are formed can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a screw rotor with helical teeth used in screw compressors, screw pumps, and the like.

(Prior art) As a means of efficiently producing screw rotors by plastic working, a material with linear teeth is conventionally extruded around a non-porous boss portion, as seen in Japanese Patent Application Laid-Open No. 50-158013. There is a method in which the material is formed and then torsionally deformed to form twisted teeth, and a die is provided with a tooth profile groove and a core mold with a helical angle, as seen in JP-A No. 62-6319 (1). A known method is to extrude a material from a die and form a screw rotor with twisted teeth and a core hole in a single process.

(Problems to be Solved by the Invention) In screw compressors, pumps, etc., the helix angle of the helix teeth is determined by the required performance such as compression ratio, and may require a helix angle of 40° or more, for example.

However, by using the former method of twisting a material with straight teeth in the prior art, the helix angle was 40''.
When machining, the amount of machining is large, so it may not be possible to obtain a uniform helix angle over the entire length of the teeth, or the helix angles of each tooth may not be the same.

In addition, in the latter method of molding using a die with a helix angle in the tooth profile groove, the helix angle is large, so there is a large resistance to extrusion in the tooth profile groove, and there is a risk that the tooth profile part will not be formed in a female rotor with a thin tooth profile. There is a lot of wear on the mold.

Therefore, it is an object of the present invention to overcome these drawbacks of the prior art and to provide a means for easily manufacturing a rotor having a core hole and high precision.

(Means for Solving the Problems) One of the means for solving the problems of the present invention is to use a die that includes a center hole, a plurality of tooth-shaped grooves extending radially from the center hole, and a core mold held within the center hole. It is characterized by comprising a step of extruding a toothed material having a core hole, and a step of inserting a core metal into the core hole of the toothed material and applying a cold or hot twist to the toothed material. do.

Another solution includes the steps of extruding a toothed material from a die having a center hole and a plurality of tooth-shaped grooves extending radially from the center hole, and drilling a core hole in the toothed material. The method is characterized by comprising the steps of inserting a metal core into the core hole of the toothed material and twisting the toothed material in a cold or hot manner.

(Function) In one of the above methods, a toothed material having straight teeth or gently twisted teeth and a core hole is extruded, and in the next step, a toothed material is formed with a core metal while preventing deformation of the core hole. A twisting force is applied to both ends of the material, imparting a twist angle to the final twist angle of the rotor.

In the other method described above, after forming the toothed material, a core hole is bored, a core metal is inserted into the core hole, and a twisting force is applied to give the final twist angle.

(Example) An example will be described below with reference to the drawings. In FIG. 1, 1 is a die for the first step of the female rotor, which is a combination of a male die 2 and a female die 3. The male die 2 has a mandrel 4 in the center connected to it by four arms 5, passages 6, 6... between the arms communicate with the merging chamber 7, and the tip of the mandrel 4 connects to the merging chamber 7. It protrudes slightly from the end.

On the other hand, the female die 3 has a center hole 8 and a radial tooth-shaped groove 9 following the center hole 8, and the mandrel 4 is inserted into the center hole 8 on the base end surface 3a side. This female die 3 is shown in Fig. 2(a).
Alternatively, it has the configuration shown in FIG. 3(a). Figure 2 (a
) is equipped with five non-twisted tooth grooves 9A extending radially from the center hole 8A, and when the material is extruded using these, the base 10 is formed as shown in FIG. 2(b).
Straight teeth 11A extending radially from A are formed, and at the same time, a toothed material 1 with a core hole 12A drilled in the center by the mandrel 4 is formed.

On the other hand, the female die 3B in FIG. 3(a) has a center hole 8.
For example, it extends radially from b and in the longitudinal force direction.
It is equipped with five tooth groove parts 9b with a helix angle of 0'',
A phase difference e exists between the inlet side indicated by the dotted line, the outlet side indicated by the solid line, and the outlet side indicated by the solid line.

When this is used, as shown in Fig. 3, a twisted tooth 11B with a helix angle of α, -20@ from the base 10B and a toothed material 2 with a core hole 12B formed in the center are formed. be done.

When a billet of highly heated aluminum alloy is pushed into die 1 in Fig. 1, it is divided into four parts by arms 5, 5, etc. of male die 2, and passes through passages 6, 6, etc. as shown by arrow A. It reaches the merging chamber 7, where it is welded and becomes one body again, and the female die 3
pushed into. By making the male die 2 have such a structure, the mandrel 4 can be shortened and the core hole will not be misaligned due to core runout. Moreover, if a mandrel is attached to a long container and the female die 3 is connected without using the male die 2 as shown in 2, a large resistance will be generated against the billet at the base end surface 3a, but if this male die 2 is used, It can be extruded with practically low resistance.

The toothed material made in the first step, or lI12
is twisted in the next second step. In this second step, the toothed material is cold or 200 to 25
Processed hot at 0°C. Insert the core bar 13 into the core hole of the material 1 or W2 as shown in FIG.
4 and the urethane rubber holder 14 of the roll chuck 15
a, 15a, and move the roll chuck l5 in the direction of arrow 1.
By twisting in the direction B, twisted teeth 11 having a twist of α2-40'', for example, are formed on the teeth extending from the base IO, and a toothed material 3 having a core hole 12 in the base IO is obtained.

By inserting the core metal 13, the base 10 and the core hole 12 are prevented from being deformed during twisting, and therefore the teeth 11 are also prevented from being deformed due to the deformation.

The accuracy of the teeth 1l is generally higher when the clearance C between the core hole l2 and the core metal 13 is smaller, and the clearance C of the female rotor of aluminum alloy can be changed by using core metals of different diameters to improve the accuracy of the two adjacent teeth after twisting. When the lead difference between the two teeth 11a and flb was determined, the curve LD shown in FIG. 10 was obtained. If the clearance C is small, the lead difference will be small and the accuracy will be improved, but if the clearance C is made too small, a locking region K will occur where the core metal 13 is locked in the core hole 12.

In this way, the rotor material 3 with good accuracy can be obtained by inserting the core metal 13 and twisting it, but this toothed material 3 may be twisted due to uneven temperature distribution during heating. Corner errors are unavoidable, and distortion also occurs in the chuck portion, so shaping is performed in the third and subsequent steps to correct this, if necessary. The shaping die 17 used in the third step is shown in FIG. 5, and its tooth grooves 18 have a helix angle approximately twice as large as that of the female die 3B in FIG. 3(a). The phase difference is 2e
It is.

This shaping die 17 is fixed, and the toothed material W obtained in the second step. By pushing it in, grasping the tip with a chuck, and pulling it out while twisting, the variation in the twist angle is corrected, and the female rotor 114 shown in FIG. 6<a>(b) is obtained.

FIGS. 7 and 8 each show a male rotor that meshes with the female rotor and has four round teeth. The male rotor lI15 in FIG. 7 has approximately semicircular round teeth 19, 19... and a core hole 20,
Using a female die, a chuck, and a shaping die having tooth grooves corresponding to the round teeth, processing is performed in the same procedure as the first, second, and third steps.

The male rotor 6 shown in FIG. 8 has approximately semicircular and hollow twisted teeth 21, and is lightened by the hollow part 22. In order to mold this male rotor, the male die 2 is used in the first step. Alternatively, use a long container and mandrel, and
Four molds are provided surrounding the mandrel, and a semi-molten material or a heated billet is pressed into the mold, and the second and third steps are carried out by the same means as described above.

Female rotor lA4 and male rotor 5 formed in this way
Or W, the shafts are inserted and fixed in the core holes 12 and 20, and the male and female rotors are rotated synchronously while maintaining a small gap in order to prevent friction and noise from occurring on the rotor engagement surfaces. An interlocking gear is fixed to the shaft.

However, it is difficult to maintain a constant gap accuracy over the entire helical tooth, and partial contact may occur during operation. In order to reduce the friction and noise generated in this case, at least one of the rotors is coated with an anti-friction resin layer as a fourth step. FIG. 9 shows the female rotor 14. An example is shown in which an anti-friction resin layer 23 is formed, and the resin layer 23 is made of synthetic materials such as polyimide, polyamide, polyamideimide, epoxy, polyvinyl chloride, silicone epoxy, silicone urethane, silicone polyester, etc. as a base. A resin is used, and as a lubricant, for example, GrSM032, WS2, BN, (CP)n SSn
Add powder, PTFE, etc., and apply composite coating to 10
The film thickness should be ~1500jm.

This film prevents metal-to-metal contact and improves sliding characteristics.

If the gap between the male and female rotors after being coated with the anti-friction resin layer is not correct and uniform, the fifth step is to remove the surface layer of the anti-friction resin layer by cutting it with a hob or grinding it with a grindstone and correct it. Therefore, a high precision screw rotor with wear resistance can be obtained.

Next, another manufacturing method will be explained with reference to FIG.

In the same figure, 25 is a die, male die 2B and female die 2.
Unlike the die 1 in FIG. 1, this die 25 is not provided with a mandrel, and the male die 26 is provided with only a passage 28 and a merging chamber 29, and the female die 27 is the same as in FIG. Has a structure.

Therefore, when the billet is pushed into the nozzle 25, a toothed material without a core hole is extruded from the female die 27, and the core hole is drilled in the material using a drill or the like. After drilling the core hole,
Similar to the toothed material made with die 1, a core metal is inserted and twisting is performed. When this die 25 is used, the extrusion pressure can be low.

(Effects of the Invention) As described above, the present invention combines forming of a toothed material by extrusion and twisting, and in the twisting process, the forming process is performed while preventing deformation of the core hole with a core bar inserted into the core hole. By doing this, you will be able to obtain highly accurate row measurements.

[Brief explanation of the drawing]

Figures 1(a) and 1(b) are a back view and a vertical cross-sectional view of a die used in the first step of the present invention, and Figure 2(a) is a front view of a female die for molding a raw material with straight teeth. (b) is the product, Figure 3 (a) is a front view of the female die for forming the toothed material with twisted teeth, Figure 4 (b) is the product, Figure 4 is an explanatory diagram of the second step, The figure is a front view of the shaping die for the third process.
Figures 6(a) and 6(b) are a front view and a sectional view of the female rotor;
Figures 7(a) and 7(b) are a front view and a sectional view of the male rotor;
Figures 8(a) and 8(b) are front views and cross-sectional views of other male rotors, Figure 9 is a cross-sectional view of a rotor coated with a resin layer, and Figure 10 is a cross-sectional view of a rotor coated with a resin layer.
The figure is a chart showing product accuracy, and FIG. 11 is a longitudinal cross-sectional view of a die used in another manufacturing method. 1, 25...Dice 2, 26...Male die 3, 3A, 3B, 27...Female die 9, 9^, 9
B... Tooth profile groove 17... Shaping die W1, lll2, 6... Toothed material 14, -5, S... Rotor 3 people outside of Figure 10 Figure 11 Figure 4 Figure 12B 6 Figure (a) Figure 6 (b)

Claims (1)

[Claims] 1. A step of extruding a toothed material having a core hole from a die including a center hole, a plurality of tooth grooves extending radially from the center hole, and a core mold held within the center hole; A method for manufacturing a screw rotor, comprising the steps of inserting a core metal into a core hole of a toothed material and applying cold or hot twist to the toothed material. 2. The method for manufacturing a screw rotor according to claim 1, wherein the toothed groove of the die is twisted, and a toothed material having twisted teeth with a gentle helix angle is extruded. 3. A step of extruding a toothed material from a die having a center hole and a plurality of tooth-shaped grooves extending radially from the center hole, a step of drilling a core hole in the toothed material, and a step of extruding the toothed material in the core hole of the toothed material. A method for producing a screw rotor, comprising the steps of: inserting a metal core into the toothed material and twisting the toothed material in a cold or hot manner.