JP4308743B2 - Screw rotor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a screw rotor used in a screw fluid machine such as a screw compressor or a screw pump, and a method for manufacturing the same.

  A screw compressor, which is an example of a screw fluid machine, includes a male rotor and a female rotor that rotate in parallel so that their rotational axes are parallel and mesh with helical teeth, and a casing that houses these male and female rotors. The working chamber for compressing the fluid to be compressed is formed by the tooth grooves of the male rotor and the female rotor and the inner wall of the casing. Since the male rotor and the female rotor (hereinafter collectively referred to as a screw rotor) and the like increase in temperature due to adiabatic compression of the fluid to be compressed and thermally expand, the clearance between the screw rotors and the clearance between the screw rotor and the casing Is increased with a margin of thermal expansion to prevent contact and damage of each member during operation. At this time, the rising temperature of the screw rotor and the thermal expansion associated therewith are not uniform or constant, and the gap is increased in consideration of the maximum thermal expansion, which causes a reduction in the performance of the compressor.

  Therefore, in order to cope with this, conventionally, a superplastic material (for example, a Zn—Al alloy, an Al—Zn—Zr alloy, an Al—Ca—Zn alloy) having teeth (screws) on the outer peripheral side and a hollow (cavity) is used. A screw rotor in which a lobe member made of an alloy or the like and a rotor shaft made of a high-strength material (for example, carbon steel for mechanical structure, alloy steel, spheroidal graphite cast iron, etc.) having a shaft hole communicating with the hollow portion of the lobe member are integrally coupled Has been proposed (see, for example, Patent Document 1). Although not clearly shown in this prior art, for example, the screw compressor is provided with a lubricating oil chamber for storing lubricating oil for lubricating and cooling the bearing, and the lubricating oil in the lubricating oil chamber is supplied to the rotor. It distribute | circulates to the hollow part of a lobe member through the shaft hole of a shaft, and cools a screw rotor.

  In addition, the above-described clew rotor manufacturing method includes arranging a cylindrical lobe member on the outer peripheral side of the intermediate portion of the rotor shaft, press-fitting the boss portion into the notch of the rotor shaft, and then integrally coupling them, Heating is performed to a temperature at which flow occurs (200 ° C.), the lobe member is pressurized from the inside, and the teeth are formed by plastic working with a mold on the outer peripheral side. After cooling, the tooth portion of the lobe member is detached from the mold due to the difference in thermal shrinkage, and the lobe member is pulled out from the mold while twisting.

JP-A-57-70985

However, there is room for improvement in the prior art described above.
That is, the screw rotor has a structure in which a lobe member is disposed on the outer peripheral side of the intermediate portion of the rotor shaft (in other words, the rotor shaft is disposed through the hollow portion of the lobe member), and the rotor shaft and the lobe member are integrally coupled. It has become. Therefore, a cooling medium such as lubricating oil that circulates in the hollow portion of the lobe member through the shaft hole of the rotor shaft cools the intermediate portion of the rotor shaft and then cools the teeth portion of the lobe member. It cannot be said that the cooling efficiency at the tooth portion of the lobe member is good, and there is room for improvement. Further, if the weight of the screw rotor is reduced, an effect such as an energy saving effect and an improvement in the response of the rotational speed control can be obtained, so there is room for improvement in terms of weight reduction. Moreover, since the tensile strength of the superplastic material is about 5 N / mm ² , the strength required for the screw fluid machine (for example, about 50 N / mm ² ) cannot be secured, and there is a problem that the practicality is poor. .

  The objective of this invention is providing the screw rotor which can aim at the improvement of the energy-saving effect and control response by weight reduction while improving cooling efficiency, and its manufacturing method.

(1) To achieve the above object, the present invention provides a screw member having a helical tooth portion formed on the outer peripheral side, a hollow portion substantially similar to the tooth portion, and one axial direction of the screw member. A screw rotor including two shaft members each having a through hole that is joined to the side and the other side and communicated with the hollow portion of the screw member , wherein the screw member is provided at least in a radial section of the hollow portion. One reinforcing plate is provided, and this reinforcing plate is provided with a through hole penetrating in the axial direction.

(2) Oite above (1), preferably, the reinforcing plate is provided with a wing means for creating a swirling flow in the hollow portion of the screw member with rotation movement.

( 3 ) In the above (1) or (2) , preferably, the tooth portion of the screw member is provided with an oil supply through hole penetrating from the hollow portion to the outer peripheral side on the seal line.

(4) In order to achieve the above object, the present invention provides a screw member having a helical tooth portion formed on the outer peripheral side, a hollow portion substantially similar to the tooth portion, and one axial direction of the screw member. And a screw rotor including two shaft members each having a through hole connected to the hollow portion of the screw member and the tooth portion of the screw member penetrating from the hollow portion to the outer peripheral side. A through hole for refueling is provided on the seal line.

  (5) In order to achieve the above object, the present invention provides a screw member having a helical tooth portion formed on the outer peripheral side, a hollow portion substantially similar to the tooth portion, and one axial direction of the screw member. In a method of manufacturing a screw rotor comprising two shaft members each having a through hole joined to each of the side and the other side and communicating with a hollow portion of the screw member, the screw rotor is divided into at least two parts in an axial cross section, An outer peripheral side split core for forming the outer peripheral side of the tooth part of the screw member is formed, and divided into at least two parts in the axial cross section, and an inner peripheral side split for forming the inner peripheral side of the tooth part of the screw member The core member is molded, and the screw member is cast using a mold incorporating the outer peripheral side split core and the inner peripheral side split core, and the axially one end and the other end of the cast screw member Each of the shaft members is welded or worn at high density. They are joined by welding.

In the manufacturing method of the screw rotor of the present invention, the outer peripheral side core for forming the outer peripheral side of the tooth part is formed by dividing the outer peripheral side core into, for example, two parts in the axial section, and the inner peripheral side of the tooth part (in other words, in other words, For example, an inner peripheral side split core in which the inner peripheral core for forming a hollow portion having a shape substantially similar to the tooth portion is divided into, for example, two in the axial cross section is formed. Then, the screw member is cast using a mold incorporating the outer peripheral side split core and the inner peripheral side split core. For example, unlike the case of molding with a superplastic material, the strength (for example, about 50 N / mm ² ) of the screw member required for the screw fluid machine can be ensured. Then, the shaft member is joined to one end and the other end of the screw member by high density welding (for example, electron beam welding, laser beam welding, light beam welding, etc.) or friction welding. Thus, unlike the case where the shaft members are joined by, for example, arc welding, a weld deposit that is not uniform in the circumferential direction is not formed, so that a weight balance in the circumferential direction can be ensured. Therefore, the trouble at the time of screw rotor rotation drive can be prevented, and performance and reliability can be improved.

  (6) In the above (5), preferably, the inner circumferential side split core is divided in a radial cross section and connected via an axial connecting member so that the hollow section of the screw member has a radial cross section. A reinforcing plate having a through hole penetrating in the axial direction is formed.

  (7) In the above (5) or (6), preferably, the thread groove is formed in a thread bottom with the same diameter at the bottom of the thread groove so that the thread groove valley diameter is substantially the same in the axial direction. The inner circumferential side split core is formed by using an inner circumferential side split core mold that has a female thread portion formed of a mountain side slope portion provided with a draft angle and is divided into at least two in the axial cross section thereof Each is molded.

  Since the cast screw member has a structure in which the inner peripheral side of the tooth part can hardly be processed, the inner peripheral side split core for forming a hollow part having a shape substantially similar to the tooth part needs to be improved in accuracy. Such inner circumferential side split cores are each formed by using an inner peripheral side core mold that is divided in the axial cross section and has the same shape as the hollow portion of the screw member, but is extracted from the inner peripheral side split core mold. It may have a portion that protrudes perpendicular to the direction (for example, the axial direction or the radial direction), and it becomes difficult to extract the inner peripheral side split core from the inner peripheral side split core mold.

  Therefore, in the present invention, the inner circumferential side split core mold is formed in a thread bottom with the same diameter at the bottom of the thread groove so that the thread groove valley diameter is substantially the same in the axial direction, and is predetermined in the axial direction. A female threaded portion comprising a mountain-side slope portion provided with a slope portion (specifically, a slope in which the slip-off start side of the inner circumferential side split core type is relatively small and gradually increases toward the slip-off end side). Have each. Using these inner circumferential side split core molds, the inner peripheral side split cores are respectively molded, and when a rotational force is applied while pulling the inner peripheral side split core to one side in the axial direction, the inner peripheral side split core mold Since the valley bottom same diameter part slides on the corresponding inner peripheral side split core and plays a guiding role, for example, the inner peripheral side split core has a structure in which the thread groove valley diameter changes in the axial direction. Compared to the case where a mold is used, the inner peripheral side split core can be easily rotated and pulled out from the inner peripheral side split core mold.

  (8) In the above (7), preferably, the inner diameter side split core type valley bottom same-diameter portion is a dimensional ratio between the width dimension in the axial direction of the female screw portion on the start side and the thread groove valley diameter. Is 10% or less, and the dimension ratio between the width dimension in the axial direction of the female screw portion on the end side of the removal and the thread groove valley diameter is 20% or less and 5% or more larger than the dimension ratio on the beginning side of the removal.

  (9) In the above (7) or (8), preferably, the inner peripheral side split core type valley bottom same diameter portion is a recessed portion provided in the valley bottom of the thread groove.

  (10) In order to achieve the above object, the present invention also provides a screw member having a helical tooth portion formed on the outer peripheral side, a hollow portion substantially similar to the tooth portion, and an axial direction of the screw member In a method of manufacturing a screw rotor including two shaft members each having a through hole joined to one side and the other side and communicating with a hollow portion of the screw member, the thread groove valley diameter is substantially the same in the axial direction. At the bottom of the thread groove and an internal thread portion formed of a thread-side slope portion formed in the screw thread and provided with a predetermined slope in the axial direction, and at least two in the axial cross section. The screw member is manufactured by plastic processing of a hollow cylindrical material using the split screw mold formed in a divided manner, and the shaft member is respectively densely welded or friction welded on one side and the other side of the screw member in the axial direction. Join.

  In the screw rotor manufacturing method of the present invention, first, a split screw mold in which a screw mold (die) for forming a tooth portion of a screw member is divided into, for example, two in an axial section is manufactured, and these split screws are manufactured. Placing the mold on the outer peripheral side of the hollow cylindrical material, applying pressure from the axial compression side of the hollow cylindrical material and the radial outer peripheral side from the inside of the hollow cylindrical material, thereby plastic processing the hollow cylindrical material with a split screw mold, A screw member is manufactured. At this time, the formed screw member may have a portion protruding perpendicular to the direction (for example, the axial direction or the radial direction) to be extracted from the split screw mold, and in this case, it is difficult to extract from the split screw mold. Become.

Therefore, in the present invention, the split screw mold has a valley bottom same diameter portion provided at the bottom of the thread groove so that the thread groove valley diameter is substantially the same in the axial direction, and a predetermined escape gradient ( In detail, the split screw type has a female thread portion including a mountain-side slope portion provided with a slope that is relatively small and has a slope that gradually increases toward the finish end side. When these split screw molds are used to form a hollow cylindrical material to produce a screw member and a rotational force is applied while pulling the screw member to one side in the axial direction, Since it slides on the peak of the member and plays a guiding role, for example, the screw member can be easily rotated and divided compared to the case of using a split screw type with a structure in which the thread groove valley diameter changes in the axial direction. Can be pulled out from the screw mold. Thereby, even if it does not use a superplastic material, a hollow cylindrical raw material can be plastically processed and the intensity | strength (for example, about 50 N / mm < ² >) required for a screw fluid machine can be ensured. Moreover, since the shaft member is joined to the one side and the other side of the screw member by high-density welding or friction welding as in the above (5), a weight balance in the circumferential direction can be ensured. Therefore, the trouble at the time of screw rotor rotation drive can be prevented, and performance and reliability can be improved.

  According to the screw rotor of the present invention, the cooling efficiency can be improved, and the energy saving effect and the control response can be improved by reducing the weight. Moreover, according to the manufacturing method of the screw rotor of this invention, required strength and the weight balance of the circumferential direction can be ensured, and performance and reliability can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is an axial sectional view showing the overall structure of the screw rotor according to the present embodiment.

  In FIG. 1, the screw rotor 1 is a male rotor used in a screw compressor or the like, and has a helical tooth portion 2 formed on the outer peripheral side and a hollow portion 3 having a shape substantially similar to the tooth portion 2. A substantially cylindrical shaft member having a member 4 and an axial through hole 6A that is joined to the axially one side (left side in FIG. 1) end 5A of the screw member 4 and communicates with the hollow portion 3 of the screw member 4. 7A and the axial direction other side (right side in FIG. 1) end part 5B of the screw member 4, and the axial direction (left-right direction in FIG. 1) through-hole 6B which is connected to the hollow part 3 of the screw member 4 is abbreviated. And a cylindrical shaft member 7B.

  The end portions 5A and 5B of the screw member 4 are formed with, for example, recesses 8A and 8B that are recessed in a substantially circular shape, and the recesses 8A and 8B are formed with openings 9A and 9B that open to the hollow portion 3, respectively. Has been. Also, for example, annular flange portions 10A and 10B are provided on the screw member 4 side of the shaft members 7A and 7B, and these flange portions 10A and 10B are fitted and joined to the recess portions 8A and 8B of the screw member 4, respectively. The screw member 4 and the shaft members 7A and 7B are integrally formed. The through holes 6A and 6B of the shaft members 7A and 7B communicate with the hollow portion 3 through the openings 9A and 9B.

  Next, the manufacturing method of the screw rotor 1 according to the present embodiment will be described. FIG. 2 is an axial sectional view showing the entire structure of a mold for casting the screw member 4, and FIG. 3 is a shaft for explaining the joining of the screw member 4 and the shaft members 7A and 7B. FIG.

  2 and 3, a mold 11 for casting the screw member 4 is incorporated into main molds 12A and 12B divided into upper and lower parts, and the main molds 12A and 12B. 2 The outer periphery side core for forming the outer periphery side, and the main molds 12A and 12B are incorporated into the main molds 12A and 12B, and the tooth portion 2 inner periphery side (in other words, the hollow portion 3) of the screw member 4 and the openings of the end portions 5A and 5B. It is comprised by the inner peripheral side core for forming the part 9A, 9B.

  The outer peripheral side core is composed of, for example, outer peripheral side split cores 13A and 13B which are divided into two in the axial direction (left and right direction in FIG. 2) cross section. Although not shown, the outer peripheral side split cores 13A and 13B are provided with pins and corresponding pin holes, and these pins and pin holes are fitted together so that the outer peripheral side split cores 13A and 13B are joined together. The outer peripheral core is assembled. The inner peripheral side core is composed of inner peripheral side split cores 14A and 14B that are divided into, for example, two in the axial cross section. Although not shown, the inner circumferential side split cores 14A and 14B are each provided with a pin and a corresponding pin hole, and the inner peripheral side split cores 14A and 14B are joined to each other by fitting these pins and pin holes. And the inner periphery side core is assembled.

  Then, molten metal (hot water) is poured into the cavity 15 from a melting port (not shown) of the mold 11 to cast the screw member 4. After cooling, the mold 11 is removed, and the outer peripheral side split cores 13A and 13B and the inner peripheral side split cores 14A and 14B are broken and the screw member 4 is taken out. And while performing the surface process of the tooth | gear part 2 outer peripheral side of the screw member 4, the edge parts 5A and 5B of the screw member 4 are cut, and the hollow parts 8A and 8B are formed.

  Then, the flange portion 10A of the shaft member 7A is press-fitted into the recess portion 8A of the one end portion 5A of the screw member 4, and the flange portion 10B of the shaft member 7B is press-fit into the recess portion 8B of the other end portion 5B. A notch 16A is formed on the outer peripheral side of the flange portion 10A of the shaft member 7A and the opening side of the corresponding recess portion 8A of the screw member 4, and an outer periphery side of the flange portion 10B of the shaft member 7B and the corresponding recess of the screw member 4 are provided. A notch portion 16B is provided in advance on the opening side of the portion 8B. These notches 16A and 16B are joined by high-density welding (for example, electron beam welding, laser beam welding, light beam welding, etc.) (at this time, the notches 16A and 16B are filled), and the screw member 4 And the shaft members 7A and 7B are integrated. The screw member 4 and the shaft members 7A and 7B may be joined by friction welding.

  Next, details of the manufacturing method of the outer peripheral side split cores 13A and 13B and the inner peripheral side split cores 14A and 14B will be described with reference to FIGS. 4A is a perspective view showing the entire structure of the outer peripheral side split core and the outer peripheral side split core formed using the outer peripheral side split core, and FIG. 4B is a section A in FIG. 4A. 4 (c) is a partially enlarged view of a portion B in FIG. 4 (a). FIG. 5A is a perspective view showing the entire structure of the inner peripheral side split core and the inner peripheral side split core formed using the inner peripheral side split core, and FIG. 5B is the perspective view of FIG. FIG. 5C is a partially enlarged view of a portion C in FIG. 5, and FIG. 5C is a partially enlarged view of a portion D in FIG.

  4 (a) to 4 (c) and FIGS. 5 (a) to 5 (c), the outer peripheral side split cores 13A and 13B have two cross sections in the axial direction (substantially left and right direction in FIG. 4 (a)). The outer peripheral side split core dies 17A and 17B (only 17A is shown in FIG. 4A) are respectively formed.

The outer peripheral side split core die 17A has a male screw portion 18 having a shape substantially similar to the tooth half 2 of the screw member 4 (in other words, a shape that is as large as the machining allowance), and both axial ends of the male screw portion 18 (FIG. 4). For example, a substantially semi-cylindrical shaft portion 19 is provided on the left side and the right side of (a). External thread portion 18 of the outer peripheral side split core type 17A includes a protrusion 20a which is convexly the summit 20 of the thread as outer thread diameter D ₁ is substantially equal to the axial direction, is formed in the screw groove 21 A predetermined drop gradient in the axial direction (specifically, the removal end side (right side in FIG. 4 (a)) of the outer peripheral side split core mold 17A is relatively small and the removal start side (left side in FIG. 4 (a)). And a groove-side gradient portion (details not shown) provided with a gradient that gradually increases toward the surface.

The protrusion 20a of the outer peripheral split core mold 17A has a dimension ratio W _1a between the width dimension W _1a (see FIG. 4 (c)) in the axial direction of the male screw part 18 at the end of removal and the thread outer diameter D _1. / D ₁ (percentage) is set to 10% or less, and gradually increases toward the removal start side, and the width dimension W _1b (see FIG. 4 (b)) on the removal start side and the thread outer diameter D ₁ The ratio W _1b / D ₁ (percentage) is set to 20% or less and 5% or more larger than the dimension ratio W _1a / D _{1 at the} end of the removal.

  Then, the outer peripheral side split core die 17A is disposed at an appropriate position in a casting frame (not shown), and the casting sand containing, for example, a thermosetting resin is filled in the casting frame, and the casting sand is heated. The inner periphery side split core 13A is formed by curing. Thereafter, the cast frame is removed (the state shown in FIG. 4A), and the outer peripheral side split core 13A is half-rotated while being pulled toward one side in the axial direction (left side in FIG. 4A). Pull out from the core mold 17A. Moreover, the outer peripheral side split core mold 17B has the same structure as the outer peripheral side split core mold 17A, and the outer peripheral side split core mold 13B is formed using the outer peripheral side split core mold 17B in the same procedure, and thereafter Then, the outer peripheral side split core 13B is pulled out from the inner peripheral side split core mold 17B by being rotated halfway while being pulled toward one side in the axial direction.

  The inner peripheral side split cores 14A and 14B are divided into two in the axial direction (substantially left and right direction in FIG. 5A), and the inner peripheral side split core types 22A and 22B (however, only 22A is shown in FIG. and a mandrel 23A, 23B (only 23A is shown in FIG. 5A).

The inner peripheral side split core mold 22 </ b> A includes a female screw portion 24 having the same shape as the inner peripheral side (in other words, the hollow portion 3) half of the tooth portion 2 of the screw member 4. Internal thread portion 24 of the inner peripheral side split core type 22A includes a recess 25a that is recessed in the valley 25 of the thread groove as the screw Mizotani diameter D ₂ is substantially the same in the axial direction, it is formed in the thread 26 A predetermined slip gradient in the axial direction (specifically, the slipping start side (right side in FIG. 5A) of the inner circumferential side split core mold 22A is relatively small and the slipping end side (left side in FIG. 5A). ) And a mountain-side gradient portion (details not shown) provided with a gradient that gradually increases toward ().

Recess 25a of the inner peripheral side split core type. 22A, the dimensional ratio _{W 2a} of the missing start side of the internal thread portion width _{W 2a} in the axial direction of 24 (see FIG. 5 (c)) and the screw Mizotani diameter _{D 2} / D ₂ (percentage) is set to 10% or less, and gradually increases toward the end of the removal, and the ratio of the width W _2b (see FIG. 5B) on the end of the removal and the thread groove valley diameter D ₂ W _2b / D ₂ (percentage) is set to 20% or less and 5% or more larger than the dimensional ratio W _2a / D _{2 at the} beginning of removal.

  Then, the inner peripheral side split core mold 22A and the core metal 23A are arranged at appropriate positions in a cast frame (not shown), and the foundry sand containing, for example, thermosetting resin is filled in the cast frame, The foundry sand is heat-cured to mold the inner circumferential side split core 14A. Thereafter, the casting frame is removed (the state shown in FIG. 5A), and the inner circumferential side split core 14A and the mandrel 23A are rotated halfway while being pulled to one side in the axial direction (left side in FIG. 5A). To draw out from the inner circumferential side split core mold 22A. The inner peripheral side split core mold 22B has the same structure as the inner peripheral side split core mold 22A, and the inner peripheral side split core 22B and the core metal 23B are divided by the same procedure. The core 14B is molded, and then the inner peripheral side split core 14B and the core 23B are pulled out from the inner peripheral side split core mold 22B by half rotation while being pulled toward one side in the axial direction.

Next, the effect of this embodiment is demonstrated.
In the present embodiment, the screw rotor 1 is a shaft member having through holes 6A and 6B communicating with the hollow portion 3 at one end 5A and the other end 5B in the axial direction of the screw member 4 having the hollow portion 3. 7A and 7B are joined to each other, and a cooling medium (for example, lubricating oil) is circulated through the through holes 6A and 6B of the shaft members 7A and 7B to the hollow portion 3 of the screw member 4 to be cooled. At this time, the hollow portion 3 of the screw member 4 is made to have a substantially similar shape to the spiral tooth portion 2 on the outer peripheral side, in other words, the thickness of the spiral tooth portion 2 is made uniform, thereby efficiently cooling the tooth portion 2. be able to. Further, compared with the conventional structure in which the shaft member is disposed through the hollow portion 3 of the screw member 4, the cooling efficiency can be improved to the extent that the shaft member is not disposed in the hollow portion 3 of the screw member 4. As a result, the thermal expansion of the screw rotor or the like can be reduced, the gap between the screw rotors and the gap between the screw rotor and the casing can be reduced, and compression performance and reliability can be improved. Further, since the weight of the screw rotor is reduced, the power can be reduced to obtain an energy saving effect, and the moment of inertia can be reduced to improve the responsiveness of the rotational speed control by an inverter or the like.

Moreover, in the manufacturing method of the screw rotor 1 of this embodiment, the outer peripheral side split cores 13A and 13B are formed by dividing the outer peripheral side core for forming the outer peripheral side of the tooth portion 2 into two in the axial cross section. The inner peripheral side split core 14A in which the inner peripheral core for forming the inner peripheral side of the tooth part 2 (in other words, the hollow part 3 having a shape substantially similar to the tooth part 2) is divided into two in the axial cross section. , 14B. And the screw member 4 is cast using the casting_mold | template 11 incorporating these outer peripheral side division | segmentation cores 13A and 13B and inner circumference side division | segmentation cores 14A and 14B. Thereby, unlike the case where the screw member 4 is formed of a superplastic material, for example, the strength (for example, about 50 N / mm ² ) required for the screw compressor or the like can be ensured. Then, the shaft members 7A and 7B are joined to the one end portion 5A and the other end portion 5B of the screw member 4 by high density welding or friction welding, respectively. Thus, unlike the case where the shaft members 7A and 7B are joined by arc welding or the like, for example, a weld deposit that is not uniform in the circumferential direction is not formed, so that a weight balance in the circumferential direction can be ensured. Therefore, the trouble at the time of screw rotor rotation drive can be prevented, and performance and reliability can be improved.

The outer peripheral side split cores 13A and 13B are formed using the outer peripheral side split core molds 17A and 17B. Then, the outer peripheral side split core type 17A (or 17B, since in parentheses correspond the same) the addition of rotational force while pulling to one side in the axial direction, as outer thread diameter D ₁ is substantially equal to the axial direction The projecting portion 20a projecting from the top 20 of the screw thread slides into the groove portion 27 (see FIG. 4 (a) described above) of the corresponding outer peripheral side split core 13A (or FIG. 4A) to serve as a guide. Therefore, for example, as compared with the case where the split core type having a structure in which the outer diameter of the screw thread changes in the axial direction is used, the outer peripheral side split core type 17A (or 17B) can be easily rotated to rotate the outer peripheral side split core. It can be extracted from 13A (or 13B). As a result, the screw member 4 having a small machining allowance on the outer peripheral side of the tooth portion 2 can be cast, and the manufacturing time for surface machining or the like can be shortened. Moreover, it becomes possible to mass-produce the outer peripheral side split cores 13A and 13B by diverting the outer peripheral side split core molds 17A and 17B, thereby reducing the cost.

Further, the inner peripheral side split cores 14A and 14B are formed using inner peripheral side split core molds 22A and 22B and cores 23A and 23B. Then, the inner peripheral side split core A (or 17B, since in parentheses correspond the same) Adding and mandrel 23A (or 23B) rotational force while pulling on one side in the axial direction, screws Mizotani diameter D ₂ is axially The recess 25a, which is recessed in the valley 25 of the thread groove so as to be substantially the same, slides on the peak portion 28 (see FIG. 5 (a) described above) of the corresponding inner peripheral side split core 14A (or 14B). Since it moves and plays a guiding role, the inner peripheral side split core 14A (or 14B) and the mandrel are compared with, for example, a split core type having a structure in which the thread groove valley diameter changes in the axial direction. 23A (or 23B) can be easily rotated and pulled out from the outer peripheral side split core mold 22A (or 22B). As a result, it is possible to cast the screw member 4 in which the accuracy of the inner peripheral side split cores 14A and 14B is increased and the thickness of the tooth portion 2 is uniform. Moreover, it becomes possible to mass-produce the inner peripheral side split cores 14A and 14B by diverting the inner peripheral side split core molds 22A and 22B, thereby reducing the cost.

Further, considering the workability of extracting the outer peripheral side split core dies 17A and 17B from the outer peripheral side split cores 13A and 13B, the width dimension of the protrusion 20a of the outer peripheral side split core dies 17A and 17B is the end of the removal. It is preferable that the size gradually increases toward the side from which the removal starts. Further, considering the workability of extracting the outer peripheral side split cores 14A and 14B from the inner peripheral side split core dies 22A and 22B, the width dimension of the recess 25a of the inner peripheral side split core dies 22A and 22B is omitted. It is preferable that the size gradually increases from the start side toward the end side. FIG. 6 is a drawing workability corresponding to the detachment end side width dimension W _1a and the detachment start side width dimension W _1b of the protrusions 20a of the outer peripheral side split core molds 17A, 17B, and the inner peripheral side split core molds 22A, 22B is a characteristic diagram showing the recess 25a omission start side width W _2a and exit end side width dimension W _2b workability extracted corresponding to the of the.

In FIG. 6, first, the vertical axis represents the dimension ratio W _1a / D ₁ (percentage) between the width dimension W _{1a at the} end of the projection 20a of the outer divided core molds 17A and 17B and the thread outer diameter D _1. The horizontal axis represents the dimensional ratio W _1b / D ₁ (percentage) between the width dimension W _1b of the protruding portion 20a of the outer peripheral divided core molds 17A and 17B and the thread outer diameter D _1. It expresses. For example, the dimensional ratio W _1a / D ₁ on the protruding end side of the protrusion 20a is set to 10% or less, the dimensional ratio W _1b / D ₁ on the protruding start side is set to 20% or less, and the dimensional ratio W _1a / D ₁ on the disconnected end side. In the case of the outer peripheral side split core molds 17A and 17B that are larger by 5% or more, the outer peripheral side split core molds 17A and 17B can be easily rotated and pulled out from the outer peripheral side split core molds 13A and 13B.

However, when the dimension ratio W _1a / D ₁ on the end side of the protrusion 20a is 0% and the dimension ratio W _1b / D ₁ on the start side is 0% or 23%, the outer peripheral side is being divided. It becomes difficult to pull out the child molds 17A and 17B. Also, when the dimension ratio W _1a / D ₁ on the end side of the protruding portion 20a is set to 10% and the dimension ratio W _1b / D ₁ on the start side of the protruding part is set to 10% or 23%, the outer peripheral side division is also performed. It becomes difficult to pull out the child molds 17A and 17B. Further, when the dimension ratio W _1a / D ₁ on the end side of the protruding portion 20a is 12% and the dimension ratio W _1b / D ₁ on the start side is 17%, the outer peripheral side split core mold 17A is also used. , 17B becomes difficult to pull out.

From the above, the dimension ratio W _1a / D ₁ on the start side of the protrusion 20a of the outer divided core molds 17A and 17B is set to 10% or less, and the dimension ratio W _1b / D ₁ on the start side of the disconnection is set to 20%. It has been found that it is desirable to make it 5% or more larger than the dimensional ratio W _1a / D _{1 at the} end of removal or less.

Further, the vertical axis represents the dimension ratio W _2a / D ₂ (percentage) between the width dimension W _{2a at} which the recess 25a of the inner circumferential side split core molds 22A and 22B begins to come off and the thread groove valley diameter D ₂ , The horizontal axis represents the dimension ratio W _2b / D ₂ (percentage) between the width dimension W _{2b at the} end of the recess 25a of the inner peripheral side divided core molds 22A and 22B and the thread groove valley diameter D ₂ . In the same manner as described above, the dimension ratio W _2a / D ₂ of the inner circumferential side split core molds 22A and 22B at the beginning of the recess 25a is set to 10% or less, and the dimension ratio W _2b / D ₂ at the end of the recess is set to It was found that it is desirable to make it 20% or less and 5% or more larger than the dimensional ratio W _2a / D ₂ on the beginning side.

  A second embodiment of the present invention will be described with reference to FIGS. The present embodiment is an embodiment in which a reinforcing plate is provided in the radial cross section of the hollow portion of the screw member.

  7 is an axial sectional view showing the entire structure of the screw rotor in the present embodiment, FIG. 8 is a radial sectional view in section VIII-VIII in FIG. 7, and FIG. 9 is a screw in the present embodiment. It is an axial direction sectional view showing the whole mold structure for casting a screw member of a rotor. 7 to 9, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The screw member 30 of the screw rotor 29 in this embodiment includes the helical tooth portion 2 formed on the outer peripheral side, the hollow portion 3 having a shape substantially similar to the tooth portion 2, and the radial direction of the hollow portion 3 ( For example, one reinforcing plate 31 is provided in the cross section in the vertical direction in FIG. The reinforcing plate 31 has, for example, three through-holes 32 (not necessarily the same size as shown in the figure) penetrating in the axial direction (left-right direction in FIG. 7) for communicating the hollow portion 3; For example, two wing-like protrusions 33 (wing means) are provided that generate a swirling flow in the hollow portion 3 along with the rotational movement of the screw member 4. The reinforcing plate 31 has a uniform weight balance in the circumferential direction.

  A mold 34 for casting the screw member 30 is incorporated in the main molds 12A and 12B divided into the upper and lower parts and the main molds 12A and 12B, and forms the outer peripheral side of the tooth part 2 of the screw member 4. The outer peripheral side split cores 13A, 13B and the main molds 12A, 12B are incorporated into the inner peripheral side (in other words, the hollow portion 3) of the tooth portion 2 of the screw member 4, the reinforcing plate 31, and the end portions 5A, 5B. And the inner peripheral side core for forming the opening portions 9A and 9B. The inner peripheral side core is composed of four inner peripheral side split cores 35A to 35D that are divided in an axial direction (left and right direction in FIG. 9) cross section and a radial direction (up and down direction in FIG. 9) cross section.

  The inner peripheral side split cores 35A and 35B are each provided with a pin (not shown) and a corresponding pin hole in the axial cross section, and the inner peripheral side split cores 35A and 35B are connected by fitting these pins and pin holes. The inner circumferential side split core on one side in the axial direction (left side in FIG. 9) is assembled. Further, the inner peripheral side split cores 35C and 35D are each provided with a pin (not shown) and a corresponding pin hole in the axial cross section, and the inner peripheral side split cores 35C and 35D are fitted by fitting these pins and pin holes. The two are joined together to assemble the inner circumferential side split core on the other side in the axial direction (right side in FIG. 9). The inner peripheral side split cores 35A and 35B on one axial side and the inner peripheral side split cores 35C and 35D on the other axial side are three columnar connecting members 36 (however, the sizes are not the same). Or may be connected in the axial direction. A recess 37 corresponding to the wing-like protrusion 33 is formed on the end surface on the other axial side of the inner peripheral split cores 35A and 35B.

  Then, molten metal (hot water) is poured into the cavity 38 from a melting port (not shown) of the mold 34 to cast the screw member 30 having the reinforcing plate 31. After cooling, the mold 34 is removed, and the outer peripheral side split cores 13A and 13B, the inner peripheral side split cores 35A to 35D, and the connecting member 36 are broken, and the screw member 30 is taken out. And while performing the surface process of the tooth part 2 outer peripheral side of the screw member 30, the edge parts 5A and 5B of the screw member 30 are cut, and the hollow parts 8A and 8B are formed.

  As in the first embodiment, the flange portion 10A of the shaft member 7A is press-fitted into the recess portion 8A of the one end portion 5A of the screw member 30, and the flange of the shaft member 7B is inserted into the recess portion 8B of the other end portion 5B. The part 10B is press-fitted. The notches 16A and 16B are joined by high-density welding or friction welding, so that the screw member 30 and the shaft members 7A and 7B are integrated.

  In the screw rotor 29 of the present embodiment configured as described above, the cooling efficiency can be improved and the energy saving effect and the control response can be improved by reducing the weight, as in the first embodiment. Moreover, compared with the said 1st Embodiment, although a weight increases only the part which provided the reinforcement board 31 in the hollow part 3 of the screw member 30, a deformation strength can be raised and compression performance can be improved. Further, by providing the wing-like protrusion 33 on the reinforcing plate 31, a swirl flow is generated in the hollow portion 3 with the rotational movement, so that the cooling efficiency can be further improved.

  Moreover, in the manufacturing method of the screw rotor 29 of this embodiment, the inner peripheral side division | segmentation core 35A-35D which divided | segmented the inner peripheral side division | segmentation core into four by the axial direction cross section and radial direction cross section is shape | molded. Therefore, the inner peripheral side split cores 35A to 35D are reduced in size and can be easily pulled out from the corresponding inner peripheral side split core type (not shown). Moreover, since the four inner peripheral side split cores 35A to 35D are assembled via the pins and the connecting member 36, the assembly accuracy of the mold 34 can be improved.

  A third embodiment of the present invention will be described with reference to FIG. The present embodiment is an embodiment in which a through hole for oil supply is provided in a tooth portion of the screw member.

  FIG. 10A is a perspective view showing the entire structure of the screw rotor according to the present embodiment, and FIG. 10B is a partially enlarged perspective view of the portion E in FIG. 10A. In FIGS. 10A and 10B, the screw rotor 39 according to the present embodiment has the same configuration and structure as those of the above-described embodiment, and description thereof will be omitted as appropriate.

  In the present embodiment, the tooth portion 40 of the screw rotor 39 has a through-hole 41 for oil supply having a diameter of, for example, about 0.2 to 5 mm that penetrates from the hollow portion 3 to the outer peripheral side. A plurality of boundary lines are provided on the movement path of the boundary line, part of which is shown by a bold line in FIG. In the oil supply type screw compressor to which the screw rotor 39 is applied, centrifugal force works along with the rotational movement of the screw rotor 39, and lubricating oil is supplied from the hollow portion 3 to the seal line 42 of the working chamber through the oil supply through hole 41. Supply. Thereby, the air leak from a working chamber can be suppressed and compression performance can be improved.

  A fourth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the screw member is formed by plastic processing of a hollow cylindrical material.

  FIG. 11 is an axial cross-sectional view showing the overall structure of the screw rotor according to the present embodiment, and FIG. 12 is an axial cross-sectional view for explaining a method for manufacturing the screw rotor according to the present embodiment.

  The screw rotor 43 according to the present embodiment has, for example, substantially cylindrical shaft portions 46A and 46B at one end (left side in FIG. 11) end 45A and the other end (right side in FIG. 11) 45B of the screw member 44. Is provided. Step portions 48A and 48B are provided on the outer peripheral sides of the end portions of the substantially cylindrical shaft members 47A and 47B, and the shaft portions 46A and 46B of the screw member 44 are fitted and joined to the step portions 48A and 48B, respectively. The screw member 44 and the shaft members 47A and 47B are integrally formed. The axial through holes 49 </ b> A and 49 </ b> B of the shaft members 47 </ b> A and 47 </ b> B communicate with the hollow portion 3 of the screw member 44.

  Also in the screw rotor 43 of this embodiment, the cooling efficiency can be improved and the energy saving effect and the control response can be improved by reducing the weight, as in the first embodiment.

  Moreover, in this embodiment, the screw member 44 is manufactured by plastic working, for example, an iron hollow cylindrical material (or pipe material) 50. Specifically, first, split screw dies 51A and 51B are manufactured by dividing a screw die (die) for forming the tooth portion 2 of the screw member 44 into, for example, two in the axial cross section. Each of the split screw molds 51A and 51B includes a female screw portion 52 having a shape substantially similar to that of the half tooth portion of the screw member 44 (in other words, a shape that is as large as the machining allowance). The female screw portion 52 of the split screw mold 51A (or 51B) is not shown in detail (similar to the female screw portion 24 of the inner peripheral split core die 22A shown in FIG. 5A), but the thread groove diameter Are substantially the same in the axial direction and have the same diameter at the bottom of the thread groove, and a predetermined escape gradient formed in the screw thread in the axial direction. And a mountain-side slope portion provided with a slope that gradually increases toward the end of the slip-off.

  Then, both axial sides (the left side and the right side in FIG. 12) of the hollow cylindrical material 50 are held by the grippers 53A and 53B, and the split screw dies 51A and 51B are arranged on the outer peripheral side of the central portion of the hollow cylindrical material 50. Thereafter, pressure is applied to the axial compression side of the hollow cylindrical material 50 using the grippers 53A and 53B, and at the same time, the inside of the hollow cylindrical material 50 is filled with, for example, compressed liquid hydraulic pressure and directed radially outward. Apply pressure. As a result, the hollow cylindrical material 50 is plastically processed by the split screw molds 51A and 51B, and the screw member 44 is manufactured. Thereafter, the screw member 44 is pulled out from the split screw molds 51A and 51B by rotating while pulling the screw member 44 to one side in the axial direction.

  Then, surface processing on the outer peripheral side of the tooth portion 2 of the screw member 44 is performed, and the end portions 45A and 45B of the screw member 44 are cut to form shaft portions 46A and 46B. Then, the shaft members 47A and 47B are respectively fitted to the shaft portions 46A and 46B of the screw member 44 and joined by high-density welding or friction welding, so that the screw member 44 and the shaft members 47A and 47B are integrated.

Thus, in the present embodiment, the screw member 44 is manufactured by forming the hollow cylindrical material 50 using the split screw molds 51A and 51B. At this time, when a rotational force is applied while pulling the screw member 44 to one side in the axial direction, the valley bottom same diameter portion of the split screw molds 51A and 51B slides on the corresponding screw member peak portion to play a guiding role. Therefore, for example, the screw member 44 can be easily rotated and pulled out from the split screw molds 51A and 51B as compared with the case of using a split screw mold having a structure in which the thread groove valley diameter changes in the axial direction. Thereby, the hollow cylindrical material 50 can be plastically processed without using a superplastic material, and the strength (for example, about 50 N / mm ² ) required for the screw fluid machine can be ensured. Moreover, since the shaft member is joined to the one side and the other side of the screw member 44 by high-density welding or friction welding as in the above-described embodiment, a weight balance in the circumferential direction can be ensured. Therefore, the trouble at the time of screw rotor rotation drive can be prevented, and performance and reliability can be improved.

It is an axial sectional view showing the whole structure of a 1st embodiment of the screw rotor of the present invention. It is an axial direction sectional view showing the whole mold structure which constitutes a 1st embodiment of a manufacturing method of a screw rotor of the present invention. It is an axial sectional view for explaining joining of a screw member and a shaft member in a 1st embodiment of a manufacturing method of a screw rotor of the present invention. The perspective view showing the whole structure of the outer periphery side division | segmentation core type | mold which comprises 1st Embodiment of the manufacturing method of the screw rotor of this invention, and the outer periphery side division | segmentation core formed using this, The elements on larger scale by A part, And FIG. The perspective view showing the whole structure of the inner periphery side division | segmentation core type | mold which comprises 1st Embodiment of the manufacturing method of the screw rotor of this invention, and the inner periphery side division | segmentation core formed using this, The partial expansion by C section It is the figure and the elements on larger scale by the D section. Extraction workability corresponding to the width dimension on the end side and the width dimension on the start side of the outer periphery-side split core type projection used in the first embodiment of the screw rotor manufacturing method of the present invention, and the inner periphery It is a characteristic view showing the extraction workability | operativity corresponding to the width dimension by the side of the removal start side of the hollow part of a side division | segmentation core type | mold, and the width dimension by the side of a removal end. It is an axial direction sectional view showing the whole structure of a 2nd embodiment of the screw rotor of the present invention. It is radial direction sectional drawing by the cross section VIII-VIII in FIG. 7, and represents the detailed structure of the reinforcement board which comprises 2nd Embodiment of the screw rotor of this invention. It is an axial sectional view showing the whole structure of the mold which constitutes a 2nd embodiment of the manufacturing method of the screw rotor of the present invention. The schematic structure of the through-hole for oil supply is represented with the perspective view showing the whole structure of 3rd Embodiment of the screw rotor of this invention, and the elements on larger scale by E part. It is an axial direction sectional view showing the whole structure of a 4th embodiment of the screw rotor of the present invention. It is axial direction sectional drawing for demonstrating 4th Embodiment of the manufacturing method of the screw rotor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw rotor 2 Tooth part 3 Hollow part 4 Screw member 5A, 5B End part 6A, 6B Through hole 7A, 7B Shaft member 11 Mold 13A, 13B Outer peripheral side split core 14A, 14B Inner peripheral side split core 22A, 22B Peripheral-side split core mold 24 Female thread portion 25 Thread groove valley bottom 25a Recess portion 26 Screw thread 29 Screw rotor 30 Screw member 31 Reinforcement plate 32 Through hole 33 Wing-like projection (wing means)
34 Mold 35A, 35B, 35C, 35D Inner peripheral side split core 36 Connecting member 39 Screw rotor 40 Tooth part 41 Oil supply through hole 42 Seal line 43 Screw rotor 44 Screw member 47A, 47B Shaft member 49A, 49B Through hole 50 Hollow Cylindrical material 51A, 51B Split screw type 52 Female thread

Claims (10)

A helical tooth portion formed on the outer peripheral side, a screw member having a hollow portion substantially similar to the tooth portion, and a hollow portion of the screw member joined to one side and the other side in the axial direction of the screw member, respectively. In a screw rotor provided with two shaft members having a through hole communicating with
The screw member has at least one reinforcing plate provided in a radial section of the hollow portion, and the reinforcing plate is provided with a through hole penetrating in the axial direction. 2. The screw rotor according to claim 1 , wherein the reinforcing plate is provided with blade means for generating a swirling flow in the hollow portion of the screw member in accordance with the rotational motion. 3. The screw rotor according to claim 1, wherein a tooth portion of the screw member is provided with an oil supply through hole penetrating from the hollow portion to the outer peripheral side on a seal line. A helical tooth portion formed on the outer peripheral side, a screw member having a hollow portion substantially similar to the tooth portion, and a hollow portion of the screw member joined to one side and the other side in the axial direction of the screw member, respectively. In a screw rotor provided with two shaft members having a through hole communicating with
The tooth portion of the screw member is provided with a through hole for oil supply penetrating from the hollow portion to the outer peripheral side on a seal line. A helical tooth portion formed on the outer peripheral side, a screw member having a hollow portion substantially similar to the tooth portion, and a hollow portion of the screw member joined to one side and the other side in the axial direction of the screw member, respectively. In a manufacturing method of a screw rotor provided with two shaft members having a through hole communicated with
Divided into at least two parts in the axial cross section, and formed an outer peripheral side split core for forming a tooth part outer peripheral side of the screw member;
Divided into at least two parts in the axial cross section, and formed an inner peripheral side split core for forming the tooth part inner peripheral side of the screw member;
Cast the screw member using a mold incorporating the outer peripheral side split core and the inner peripheral side split core,
A method for manufacturing a screw rotor, characterized in that the shaft member is joined to one end and the other end in the axial direction of the cast screw member by high-density welding or friction welding, respectively.   The screw rotor manufacturing method according to claim 5, wherein the inner circumferential side split core is divided in a radial cross section and connected via a connecting member so that the radial cross section of the hollow portion of the screw member has an axial direction. A method of manufacturing a screw rotor, comprising: forming a reinforcing plate having a through hole penetrating through the screw rotor.   7. The method of manufacturing a screw rotor according to claim 5, wherein the thread groove valley diameter is substantially the same in the axial direction. The inner circumferential side split core is respectively formed by using an inner circumferential side split core mold having a female thread portion composed of a mountain side slope portion provided with a gradient and divided into at least two in the axial cross section thereof. A method of manufacturing a screw rotor, characterized by molding.   The screw rotor manufacturing method according to claim 7, wherein the inner diameter side split core type valley bottom same-diameter portion is a dimensional ratio between the width dimension in the axial direction of the female screw portion on the start side and the thread groove valley diameter. Is 10% or less, and the dimension ratio between the width dimension in the axial direction of the female screw portion on the end side of the removal and the thread groove valley diameter is 20% or less and 5% or more larger than the dimension ratio on the beginning side of the removal. The screw rotor casting method.   9. The screw rotor casting method according to claim 7, wherein the inner diameter side split core type valley bottom same-diameter portion is a recessed portion recessed in the bottom of the thread groove. Casting method. A helical tooth portion formed on the outer peripheral side, a screw member having a hollow portion substantially similar to the tooth portion, and a hollow portion of the screw member joined to one side and the other side in the axial direction of the screw member, respectively. In a manufacturing method of a screw rotor provided with two shaft members having a through hole communicated with
An internal thread portion comprising a valley bottom same diameter portion provided at the bottom of the thread groove and a mountain side slope portion provided with a predetermined escape gradient in the axial direction so that the thread groove valley diameters are substantially the same in the axial direction. And using the split screw mold that is divided into at least two in the axial cross section, plastically processing the hollow cylindrical material to produce the screw member,
A method for manufacturing a screw rotor, comprising: joining the shaft member to one side and the other side in the axial direction of the screw member by high-density welding or friction welding.

Images