JP3594691B2 - Screw compressor - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to, for example, a screw compressor used for a supercharger of a vehicle.
[0002]
[Prior art]
Japanese Utility Model Publication No. Hei 2-37286 discloses a "rotor of a screw type supercharger or a compressor". FIG. 9 shows a screw-type supercharger 201 using this rotor.
[0003]
It includes male and female screw rotors 203 and 205, a compressor casing 207, a suction port 209 and a discharge port 211 provided in the compressor casing 207, and the like. Due to the rotation of the screw rotors 203 and 205, the pressure is fed in the axial direction and is discharged from the discharge port 211.
[0004]
Each of the screw rotors 203 and 205 is composed of a rotor shaft 213 and 215 made of steel and rotor bodies 217 and 219 made of aluminum alloy, respectively, and has a large moment of inertia.
[0005]
Generally, screw type compressors are often used in superchargers of vehicles. Since the screw type compressor rotates at high speed, if the moment of inertia of the screw rotors 203 and 205 is large, the driving energy loss is large, the response at the time of acceleration is deteriorated, and the electromagnetic clutch which intermittently connects the engine and the supercharger is prevented from slipping. To do this, the electromagnetic clutch must be large. Furthermore, when the moment of inertia is large, the rotors 203 and 205 come into contact during rapid acceleration and deceleration, and the coating on the surfaces of the rotors 203 and 205 may be peeled off.
[0006]
[Problems to be solved by the invention]
In order to reduce the moment of inertia, a hollow portion 223 may be provided as in a rotor 221 shown in FIG. 10. However, pressure leaks from the discharge side to the suction side via the hollow portion 223, and the efficiency is reduced. Further, if partition portions 229 are provided in the hollow portions 227 and 227 as in the rotor 225 shown in FIG. 11, pressure leakage can be prevented, but a bag portion 231 is formed on the discharge side. The gas accumulates and gas flows back from between the screw rotors to the suction side.
[0007]
Accordingly, an object of the present invention is to provide an efficient screw type compressor in which the moment of inertia of a screw rotor is small, pressure leakage does not occur, and the efficiency is high.
[0008]
[Means for Solving the Problems]
The screw type compressor according to claim 1, wherein the male and female screw rotors mesh with each other at a screw-shaped toothed portion formed in the rotor body, and include these, and have a suction port on one axial side. A compressor casing having a discharge port on the other side in the direction, a hollow portion provided in the tooth portion of one or both screw rotors and communicating with the suction port, and a hollow portion provided at the discharge port side end of the tooth portion. The rotor body is formed by casting a rotor body, a hollow portion and a partition portion are provided in the toothed portion, and an opening provided in the partition portion and closed by a pin is provided .
[0009]
A screw type compressor according to claim 2, wherein the male and female screw rotors mesh with each other at a screw-shaped toothed portion formed in the rotor body, these are included, and a suction port is provided on one side in the axial direction. A compressor casing having a discharge port on the other side in the direction, a hollow portion provided in the tooth portion of one or both screw rotors and communicating with the suction port, and a hollow portion provided at the discharge port side end of the tooth portion. And a balancer section for balancing rotation with the partition section is provided on the inner periphery of the hollow section.
[0010]
The screw-type compressor according to claim 3 is the screw-type compressor according to claim 2 , wherein a rib in a tooth ridge direction is provided on an inner periphery of the hollow portion.
[0011]
The screw-type compressor according to claim 4 is the screw-type compressor according to claim 2 , wherein a rib in the rotation direction is provided on the inner periphery of the hollow portion.
[0013]
[Action]
The screw type compressor according to each claim has a male screw type and a female type screw rotor that mesh with each other at a screw-shaped tooth portion of the rotor body, and includes these and has an intake port on one side in the axial direction and the other side in the axial direction. In a screw compressor having a compressor casing having a discharge port, a hollow portion communicating with the suction port is provided in one or both of the male screw rotor and the female screw rotor, and A partition portion for closing the hollow portion was provided at the end on the discharge port side.
[0014]
As described above, the hollow structure of the tooth traces significantly reduces the moment of inertia of the screw rotor. For example, a vehicle equipped with the screw compressor of the present invention as a supercharger greatly improves the response during acceleration. In addition, the size of the electromagnetic clutch for intermittently connecting the engine and the supercharger can be reduced. Furthermore, since the moment of inertia is small, contact between the screw rotors is prevented even during rapid acceleration or deceleration, and the coating on the rotor surface can be thinned or eliminated.
[0015]
Further, since the hollow portion is closed by the partition, no pressure leakage occurs between the discharge side and the suction side. In addition, since the partition portion is provided at the end of the toothed portion (hollow portion) on the side of the discharge port, the bag portion 231 is not formed on the discharge side unlike the conventional rotor 225 of FIG. There is no backflow to the suction side between each screw rotor. Thus, a decrease in efficiency due to pressure leakage or the like is prevented.
[0016]
Furthermore, since the hollow portion communicates with the suction port, the screw rotor is cooled by fresh gas entering the hollow portion from the suction side, and thermal expansion is reduced, so the clearance between the screw rotors and the screw rotor and the compressor casing are reduced. The proper clearance is always maintained, and the expected performance is maintained.
[0017]
Further, the hollow portion forms a Helmholtz resonance tube, which reduces noise on the suction port side by a resonance phenomenon.
[0018]
Screw compressor according to claim 1, casting a B over data body, is provided with a hollow portion and a partition wall in the tooth trace portion. As described above, the rotor body having the toothed portion of the hollow structure having one end closed by the partition can be easily manufactured by casting, and has high productivity and low cost. In addition, the hollow structure reduces the thickness of the rotor body, improves the flow of molten metal during casting, reduces the retention of air bubbles, and improves the rotational balance, making it easier to balance or eliminating the need for balancing. Become. Further, the screw type compressor according to claim 2 is provided with a balancer section that balances the rotation with the partition wall on the inner periphery of the hollow section, and the screw rotor with the improved rotation balance can withstand higher-speed rotation. As a result, the capacity and discharge pressure of the screw compressor can be increased.
[0019]
The screw type compressor according to claims 3 and 4 is the screw type compressor according to claim 2 , wherein ribs are provided in the inner periphery of the hollow portion in the tooth streak direction and the rotation direction, respectively. The rigidity of the screw rotor is improved, the screw rotor can withstand a larger load, and the tooth ridges are less deformed even during rapid acceleration / deceleration, so that contact between the screw rotors is prevented.
[0020]
In addition, the ribs act as cooling fins, and the cooling effect of the screw rotor by the gas entering the hollow portion from the suction side is improved, and the thermal expansion is further reduced, so that each clearance between the screw rotor and between the screw rotor and the compressor casing is reduced. Fluctuations are reduced and performance is stable.
[0021]
Further, in the screw type compressor according to the third aspect, the ribs in the direction of the tooth traces are easily removed from the mold at the time of molding, for example , so that the casting is easy and the productivity is high.
[0023]
【Example】
A first embodiment of the present invention will be described with reference to FIGS . FIG. 1 shows a supercharger 1 using this embodiment. The left and right directions are the left and right directions in FIG. 1, and members and the like without reference numerals are not shown.
[0024]
As shown in FIG. 1, the supercharger 1 includes an input pulley 3, a speed increasing gear set 5, a timing gear set 7, a screw compressor 9 of the embodiment, and the like.
[0025]
The input pulley 3 is supported by a bearing 11 on a compressor casing 13, is spline-connected to an input shaft 15, and is fixed by bolts 17 and washers 19. The input pulley 3 is connected to a pulley on the crankshaft side via a belt. An electromagnetic clutch is disposed on the crankshaft-side pulley, and connects and disconnects the engine and the supercharger 1. When the electromagnetic clutch is connected, the input pulley 3 is driven to rotate by the driving force of the engine.
[0026]
The input shaft 15 is supported inside the casing 13 by a ball bearing 21, and a seal 25 is arranged between the collar 23 mounted on the input shaft 15 and the casing 13 to prevent oil leakage.
[0027]
The speed increasing gear set 5 includes large-diameter and small-diameter speed increasing gears 27 and 29 that mesh with each other, and the timing gear set 7 includes large-diameter and small-diameter timing gears 31 and 33 that mesh with each other. The air compressor 9 includes male and female screw rotors 35 and 37.
[0028]
The large-diameter speed increasing gear 27 is formed integrally with the right end of the input shaft 15, and the small-diameter speed increasing gear 29, together with the large-diameter timing gear 31, is attached to the rotor shaft 39 of the female screw rotor 37 by a key 41. The nuts 43 are connected and prevented from falling off. The small-diameter timing gear 33 is connected to a rotor shaft 47 of the male screw rotor 35 via a taper lock mechanism 45.
[0029]
The taper lock mechanism 45 engages the timing gear 33 with the timing gear 31 in a state where the screw rotors 35 and 37 are not in contact with each other, and then tightens and locks the nut 49 to rotate the screw rotors 35 and 37 in the rotation direction. Perform positioning.
[0030]
The rotor shafts 47 and 39 of the screw rotors 35 and 37 are supported on the casing 13 at the left end by a ball bearing 51 and by a collar 53 and a roller bearing 55 mounted on the right end. Further, a seal 59 is arranged between the collar 57 mounted on the left end of the rotor shafts 47 and 39 and the casing 13, and a seal 61 is arranged between the collar 53 on the right end and the casing 13. Prevents air leakage.
[0031]
The driving force of the engine input from the pulley 3 is increased by the speed increasing gear set 5, and drives the screw rotors 35 and 37 to rotate via the timing gear set 7. The driven air compressor 9 sends the intake air sucked in from the suction port 63 to the left side in the axial direction between the screw rotors 35 and 37, discharges it from the discharge port 65, and supplies it to the engine.
[0032]
Each of the screw rotors 35, 37 is composed of rotor shafts 47, 39 and rotor bodies 67, 69 fixed to the outer periphery thereof.
[0033]
As shown in FIGS. 2, 3 and 4, the rotor body 67 of the male screw rotor 35 has three screw-shaped toothed portions 71. The rotor body 67 is formed by casting, and a hollow portion 73 communicating with the suction port 63 is formed in the tooth trace 71, and the hollow portion 73 is closed at an end of the tooth trace 71 on the discharge port 65 side. A partition 75 is provided. Note that an opening 77 is provided in the partition wall portion 75 to facilitate casting into a casting mold and degassing during casting. After casting, this opening 77 is closed by screwing a pin 79.
[0034]
In addition, a balancer section 81 that balances the rotation of the rotor body 67 is provided at the end of the hollow section 73 on the suction port 63 side, facing the mass of the partition wall section 75.
[0035]
Thus, the supercharger 1 is configured.
[0036]
As described above, the screw type compressor 9 has a very small moment of inertia due to the hollow tooth structure of the toothed portion 71 of the male screw rotor 35 having a large tooth thickness. Is greatly improved, and slippage due to intermittent connection with the engine does not occur, so that the electromagnetic clutch between the engine and the supercharger 1 can be reduced in size. Further, since the moment of inertia is small, the contact between the screw rotors 35 and 37 is prevented even during rapid acceleration or deceleration, and the coating on the rotor surface can be thinned or eliminated.
[0037]
Since the hollow portion 73 is closed by the partition wall portion 75, no pressure leakage occurs between the discharge side and the suction side. In addition, since the partition wall portion 75 is provided at the end of the toothed portion 71 on the discharge port 65 side, unlike the conventional example of FIG. 11, the bag portion 231 is not formed on the discharge side of the rotor 225. It does not flow backward between the screw rotors 35 and 37 to the suction side. Thus, a decrease in efficiency due to pressure leakage or the like is prevented.
[0038]
Since the hollow portion 73 communicates with the suction port 63, the screw rotor 35 is cooled by fresh outside air entering the hollow portion 73 from the suction side, and thermal expansion is reduced. Therefore, the clearance 83 between the screw rotors 35 and 37 and the clearance 85 between the screw rotor 35 and the compressor casing 13 are always properly maintained, and the expected performance is maintained.
[0039]
Since the hollow portion 73 forms a Helmholtz resonance tube and reduces noise on the suction port 63 side by a resonance phenomenon, the supercharger 1 is accordingly quieter.
[0040]
Since the balancer portion 81 is provided on the inner periphery of the hollow portion 73 to offset the rotational imbalance of the rotor body 67 due to the provision of the partition portion 75 on the toothed portion 71 and improve the rotational balance, the screw rotor 35 is improved. Can withstand higher-speed rotation, increase the load on the supercharger 1, and increase the capacity and discharge pressure.
[0041]
Next, a second embodiment of the present invention will be described with reference to FIGS . Na us, members of the member with the same function of the first embodiment in the description of this embodiment cited giving the same reference numerals, explanation of these same functional members are omitted. The left and right directions are the left and right directions in FIG.
[0042]
5 and 6 show a male screw rotor 87 used in this screw compressor. The male screw rotor 87 meshes with the female screw rotor 37 via the timing gear set 7 without contacting each other.
[0043]
The screw rotor 87 includes a rotor shaft 47 and a rotor main body 89 fixed to the outer periphery thereof.
[0044]
As shown in FIGS. 5 and 6, the rotor main body 89 of the screw rotor 87 has three screw-shaped toothed portions 91. The rotor body 89 is processed by casting. A hollow portion 93 communicating with the suction port 63 is formed in the toothed portion 91, and a partition wall 95 for closing the hollow portion 93 is provided at an end of the toothed portion 91 on the discharge port 65 side. As in the case of the screw rotor 35, an opening 97 is provided in the partition wall 95 to facilitate casting and degassing of the rotor main body 89 during casting of the rotor main body 89, and to make this opening after casting. A pin 79 is screwed into the portion and closed.
[0045]
At the end of the hollow portion 93 on the suction port 63 side, a balancer portion 99 that balances the rotation of the rotor main body 89 is provided to face the mass of the partition wall portion 95.
[0046]
In addition, four ribs 103 are formed on the base 101 of the rotor body 89 in the direction of the teeth.
[0047]
In this way, the male screw rotor 87 is lightweight and has a reduced moment of inertia, as in the first embodiment, and the screw compressor of the embodiment is replaced with a supercharger, by forming the thick tooth portion 91 with a hollow structure. The improved vehicle has improved response during acceleration, and the engine-side electromagnetic clutch can be downsized. In addition, since the rotors 87 and 37 do not come into contact with each other even during rapid acceleration and deceleration, the coating of the rotors 87 and 37 can be thinned or eliminated. Further, since the thin rotor body 89 has few bubbles during casting, the screw rotor 87 has a good rotational balance.
[0048]
Since the hollow part 93 is closed by the partition part 95, no pressure leakage occurs between the discharge side and the suction side. Since the partition wall 95 is provided at the end of the toothed portion 91 on the side of the discharge port 65, unlike the conventional example of FIG. 11, the bag 231 is not formed on the discharge side. , 37 does not flow back to the suction side. Thus, a decrease in efficiency due to pressure leakage or the like is prevented.
[0049]
Since fresh air entering the hollow portion 93 communicating with the suction port 63 cools the screw rotor 87 and reduces thermal expansion, the clearance between the screw rotors 87 and 37 and the space between the screw rotor 87 and the compressor casing 13 are reduced. The proper clearance is always maintained, and the expected performance is maintained.
[0050]
Since the hollow portion 93 forms a Helmholtz resonance tube and reduces noise on the suction port 63 side by a resonance phenomenon, the screw-type compressor of the embodiment becomes quieter accordingly.
[0051]
Since the rotation balance with the partition wall portion 95 is balanced by the balancer portion 99, the screw rotor 87 can withstand higher speed rotation, and the screw type compressor of the embodiment increases the load and increases the capacity and discharge pressure. Becomes possible.
[0052]
In addition to this, the rigidity of the toothed portion 91 is improved by the reinforcing effect of the rib 103, so that the screw rotor 87 can withstand a larger load, and the toothed portion 91 is deformed even during rapid acceleration / deceleration. And the contact between the screw rotors 87 and 37 is prevented. Further, since the ribs 103 function as cooling fins, the cooling effect of the screw rotor 87 by the outside air is improved, and the thermal expansion is further alleviated. Clearance fluctuations are reduced.
[0053]
Further, since the ribs 103 in the tooth lead direction are easy to remove from the mold, the rotor body 89 is easy to cast and the productivity is high.
[0054]
Next, a third embodiment of the present invention will be described with reference to FIGS . Na us, members of the member with the same function of the above first and second embodiments in the description of this embodiment cited giving the same reference numerals, explanation of these same functional members are omitted. The left and right directions are the left and right directions in FIG.
[0055]
7 and 8 show a male screw rotor 105 used in the screw compressor. The male screw rotor 105 is engaged with the female screw rotor 37 via the timing gear set 7 without being in contact with each other.
[0056]
The screw rotor 105 includes a rotor shaft 47 and a rotor main body 107 fixed to the outer periphery thereof.
[0057]
As shown in FIGS. 7 and 8, the rotor main body 107 of the screw rotor 105 has three screw-shaped toothed portions 109. The rotor body 107 is formed by casting, and a hollow portion 111 communicating with the suction port 63 is formed in the tooth portion 109, and the hollow portion 111 is closed at an end of the tooth portion 109 on the discharge port 65 side. A partition 113 is provided. As in the case of the screw rotors 35 and 87 described above, at the time of casting, an opening 115 provided in the partition wall 113 facilitates casting into a mold and degassing, and a pin 79 is screwed into the opening 115 after casting. It is worn and closed.
[0058]
At the end of the hollow portion 111 on the suction port 63 side, a balancer portion 117 that balances the rotation of the rotor body 107 is provided so as to face the mass of the partition portion 113.
[0059]
Further, seven ribs 121 are formed on the base 119 of the rotor main body 107 in the rotation direction.
[0060]
Thus, the male screw rotor 105 is light in weight and the moment of inertia is reduced as in the first and second embodiments, and the screw type compressor of the embodiment is superimposed. The charged vehicle improves the response during acceleration and makes the electromagnetic clutch on the engine smaller. Also, since the moment of inertia of the screw rotor 105 is small and the rotors 105, 37 do not come into contact, the coating of each rotor 105, 37 can be thinned or eliminated. Furthermore, since the thin rotor body 107 has few air bubbles at the time of casting, the male screw rotor 105 has a good rotational balance.
[0061]
Since the hollow part 111 is closed by the partition part 113, no pressure leakage occurs between the discharge side and the suction side. Since the partition 113 is provided at the end of the toothed portion 109 on the side of the discharge port 65, unlike the conventional example of FIG. 11, the bag 231 is not formed on the discharge side. , 37 does not flow back to the suction side. Thus, a decrease in efficiency due to pressure leakage or the like is prevented.
[0062]
Since the screw rotor 105 is cooled by external air entering the hollow portion 111 communicating with the suction port 63 and thermal expansion is reduced, each clearance between the screw rotors 105 and 37 and between the screw rotor 105 and the compressor casing 13 is reduced. Is always properly maintained, and the expected performance is maintained.
[0063]
The hollow portion 111 forms a Helmholtz resonance tube and reduces noise on the suction port 63 side by a resonance phenomenon, so that the screw type compressor of the embodiment becomes quieter accordingly.
[0064]
Since the rotation balance with the partition wall portion 113 is maintained by the balancer portion 117, the screw rotor 105 can withstand higher speed rotation, and the screw type compressor of the embodiment increases the load and increases the capacity and discharge pressure. Becomes possible.
[0065]
Further, the rigidity of the tooth portion 109 is improved by the reinforcing effect of the rib 121, the screw rotor 105 can withstand a larger load, and the deformation of the tooth portion 109 is small even at the time of rapid acceleration / deceleration. Contact between the screw rotors 105 and 37 is prevented. The ribs 121 function as cooling fins to improve the cooling effect of the outside air on the screw rotor 105 and further alleviate the thermal expansion. Therefore, each clearance between the screw rotors 105 and 37 and between the screw rotor 105 and the compressor casing 13 is reduced. Fluctuations are reduced.
[0066]
In each of the embodiments described above, the example in which the male screw rotor has a hollow structure according to the configuration of the present invention has been described. However, in the present invention, the female screw rotor may have a hollow structure, or the male screw rotor may have a hollow structure. Both the female and female screw rotors may have a hollow structure.
[0067]
Further, the screw rotor in the present invention may be manufactured by a method other than casting, for example, by pressing a plate material.
[0068]
【The invention's effect】
The screw-type compressor according to each claim is a screw-type compressor including a male and female screw rotors, and a compressor casing including these and having a suction port on one axial side and a discharge port on the other axial side. In the compressor, one or both of the male screw rotor and the female screw rotor is provided with a hollow portion communicating with the suction port at the tooth portion of the rotor body, and a hollow portion at the discharge port side end of the tooth portion. A closed partition was provided.
[0069]
In this way, the toothed portion has a hollow structure and the moment of inertia of the screw rotor is reduced.For example, a vehicle equipped with the screw type compressor of the present invention as a supercharger has improved response during acceleration, and has an improved engine and The electromagnetic clutch for connecting and disconnecting with the supercharger can be made smaller. Furthermore, since the contact between the screw rotors is prevented even when the moment of inertia is small and sudden acceleration or deceleration is performed, the coating on the rotor surface can be thinned or eliminated.
[0070]
In addition, since the hollow portion is closed by the partition, pressure leakage between the discharge side and the suction side is prevented, and the partition is provided at the end of the toothed portion on the discharge port side. Since a bag portion is not formed differently on the discharge side, high-pressure gas does not flow back between the screw rotors to the suction side. Thus, a decrease in efficiency due to pressure leakage or the like is prevented.
[0071]
Furthermore, since the screw rotor is cooled by the gas entering from the suction side into the hollow part communicating with the suction port and the thermal expansion is reduced, the clearance between the screw rotor and the clearance between the screw rotor and the compressor casing are always appropriate. And the expected performance is maintained.
[0072]
Further, since the hollow portion forms a Helmholtz resonance tube, and the noise on the suction port side is reduced by the resonance phenomenon, the operation sound becomes quieter.
[0073]
Screw compressor according to claim 1, is provided with a hollow portion and a partition wall in the tooth trace portion casting a B over data body. A rotor body having a hollow structure toothed end closed at one end by a partition can be easily manufactured by casting, and has high productivity and low cost. In addition, the hollow structure reduces the thickness of the rotor body, improves the flow of molten metal during casting, reduces the retention of air bubbles, and improves the rotational balance, making it easier to balance or eliminating the need for balancing. Become. In addition, the screw type compressor according to claim 2 is provided with a balancer portion and balances the rotation with the partition portion, so that the screw rotor can withstand higher speed rotation, and the capacity and discharge pressure of the screw type compressor are reduced. Increase is possible.
[0074]
The screw type compressor according to claims 3 and 4 is the screw type compressor according to claim 2 , wherein the ribs in the tooth direction and the rotation direction are provided on the inner periphery of the hollow portion, respectively. Since the rigidity is improved, the screw rotor can withstand a larger load, and the tooth traces are less deformed even during rapid acceleration / deceleration, contact between the screw rotors is prevented. In addition, the ribs act as cooling fins to improve the cooling effect of the screw rotor by gas entering the hollow portion from the suction side and further reduce the thermal expansion, so that the clearance between the screw rotors and between the screw rotor and the compressor casing is reduced. Fluctuations are reduced and performance is stable.
[0075]
In the screw type compressor according to the third aspect, since the ribs are provided in the tooth streak direction, for example , it is easy to remove from the mold at the time of molding , and the productivity is high.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of the present invention, in which a male screw rotor 35 shows a cross section taken along the line XX of FIG. 4;
FIG. 2 is a front view of the male screw rotor 35.
FIG. 3 is a view taken in the direction of arrow A in FIG. 2;
FIG. 4 is a view as viewed in the direction of arrow B in FIG. 2;
FIG. 5 is a side view of a male screw rotor 87 used in a second embodiment of the present invention as viewed from the opening side of a hollow portion 93;
FIG. 6 is a sectional view taken along the line YY of FIG. 5;
FIG. 7 is a side view of the male screw rotor 105 used in the third embodiment of the present invention as viewed from the opening side of the hollow portion 111.
FIG. 8 is a sectional view taken along the line ZZ of FIG. 7;
FIG. 9 is a plan view showing a conventional screw type compressor.
FIG. 10 is a sectional view showing a conventional screw rotor.
FIG. 11 is a sectional view showing another conventional screw rotor.
[Explanation of symbols]
1 Screw compressor 13 Compressor casing 35, 87, 105 Male screw rotor 37 Female screw rotor 63 Inlet port 65 Outlet port 67, 89, 107 Rotor main body 71, 91, 109 Toothed strip 73, 93, 111 Hollow section 75 , 95, 113 Partition parts 81, 99, 117 Balancer parts 103 Ribs (toothed direction)
121 rib (rotation direction)

Claims (4)

Male and female screw rotors meshing with each other with screw-shaped toothed portions formed on the rotor body, a compressor including these, and having an intake port on one axial side and a discharge port on the other axial side A casing, a hollow portion provided at the toothed portion of one or both screw rotors and communicating with the suction port, and a partition provided at the discharge port side end of the toothed portion and closing the hollow portion , the rotor comprising: A screw-type compressor comprising: a main body formed by casting; a hollow portion and a partition portion provided in a toothed portion; and an opening provided in the partition portion and closed by a pin . Male and female screw rotors meshing with each other with screw-shaped toothed portions formed in the rotor body, a compressor including these, and having a suction port on one axial side and a discharge port on the other axial side A casing, a hollow portion provided on the toothed portion of one or both screw rotors and communicating with the suction port, and a partition provided on the discharge port side end of the toothed portion and closing the hollow portion, comprising a hollow portion. A screw type compressor provided with a balancer section on the inner periphery of the section to balance the rotation with the partition section. 3. The screw type compressor according to claim 2 , wherein a rib in a tooth direction is provided on an inner periphery of the hollow portion. 3. The screw compressor according to claim 2 , wherein a rib in the rotation direction is provided on an inner periphery of the hollow portion.

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