JP5595048B2 - Screw compressor - Google Patents

Description

  The present invention relates to a screw compressor.

  Conventionally, as shown in Patent Document 1, a compression space formed by engaging a male rotor and a female rotor, a suction port formed on one side of the rotor in communication with the compression space, and a rotor in communication with the compression space A screw compressor having a discharge port formed on the other side is known. In the male rotor and the female rotor, rotor shafts are formed so as to extend on both sides of the suction port side and the discharge port side of the rotor, respectively. Each rotor shaft is provided with a bearing for supporting a radial load and a bearing for supporting an axial load.

  In this screw compressor, the working medium sucked from the suction port is compressed in the compression space and discharged from the discharge port. When the working medium is compressed in the compression space, forces in the axial direction and the radial direction are applied to the male rotor and the female rotor. Therefore, selection of each bearing needs to be performed based on the said force.

On the other hand, the cross section orthogonal to the axis of the male rotor and female rotor (the cross section of the portion where the bearing is arranged) is as shown in FIG. The screw rotor diameters of the male rotor and female rotor are determined from the shape of the compression space. When the screw rotor diameter of the male rotor and the female rotor is determined, the rotation axis distance D _CD of the screw rotors is determined. Within this range of the rotational axis distance D _CD, in the axial direction of the bearing and the female rotor side of the bearing of the male rotor side, it is necessary to provide an excess thickness portion for fixedly provided on substantially the same position. When the outer diameter D _M of the bearing on the male rotor side, the outer diameter D _F of the bearing on the female rotor side, and the length t in the direction perpendicular to the rotor axis of the surplus portion, the relationship of the following equation (1) is established.

In the formula (1), it is necessary to satisfy the distance D _CD > 0, the outer diameter D _M > 0, the outer diameter D _F > 0, and the surplus portion t> 0. In general, the larger the outer diameter of the bearing, the larger the load can be supported. However, there is a limit to increase the size of the bearing as can be seen from the equation (1). Therefore, it has become necessary to dispose a bearing that can withstand as much load as possible within a limited geometric structure.

JP-A-6-173871

  The present invention can withstand heavy loads in a geometric structure determined from the distance between the rotor shaft centers between the rotor shaft of the screw rotor and the rotor shaft arranged in parallel with the rotor shaft. Another object of the present invention is to provide a screw compressor capable of advantageously disposing a large size bearing.

As means for solving the above-mentioned problems, the screw compressor of the present invention has a first screw rotor that meshes and a rotor chamber that rotatably accommodates a second screw rotor disposed in parallel with the first screw rotor. A compressor body, a rotor having a motor shaft, and a motor section having a motor chamber that houses a stator disposed on the outer periphery of the rotor; a rotor chamber of the compressor body section; and In the screw compressor in which a through hole is provided between the motor chambers of the motor unit and the rotor shaft of the first screw rotor and the motor shaft of the motor unit are connected through the through hole, the rotor chamber side of the motor chamber is disposed on the rotor chamber side. Provided on the end surface is a first recess that is coaxial with the through hole and has a larger diameter than the through hole. The motor side rotor shaft of the first screw rotor is disposed in the first recess, and the motor side rotor shaft Through the motor shaft which is sintered or directly, the outer diameter of the support is disposed a first roller bearing D _M, are arranged at different positions in the first recess and the axial direction, the motor of the rotor chamber, A chamber-side end face is provided with a second recess disposed coaxially with the motor-side rotor shaft of the second screw rotor and accommodating the motor-side rotor shaft of the second screw rotor, and the second screw is provided in the second recess. A second roller bearing having an outer diameter D _F (provided that the outer diameter D _F is different from the outer diameter D _M ) supporting the motor-side rotor shaft of the rotor is disposed, and the D _M , the D _F , and the (D _M + D _F ) × 1/2 ≧ D _CD and D _M > D _F are established between the axial distances D _CD of the first and second screw rotors.

According to this configuration, the first recess provided on the end surface of the motor chamber on the rotor chamber side and the second recess provided on the end surface of the rotor chamber on the motor chamber side are arranged at different positions in the axial direction. Yes. Therefore, the outer diameter D _M of the first roller bearing disposed in the first recess, the outer diameter D _F of the second roller bearing disposed in the second recess, and the shafts of the first and second screw rotors (D _M + D _F ) × 1/2 ≧ D _CD and D _M > D _F can be established between the inter-center distances D _CD , and D _M and D _F can be increased. it can.

  According to the present invention, in a geometric structure determined from the distance between the axial centers between the first screw rotor and the second screw rotor arranged in parallel with the first screw rotor, A bearing that can withstand, that is, a large size, can be advantageously arranged.

The figure which shows the screw compressor concerning this invention. The principal part enlarged view of the screw compressor concerning this invention. The figure which shows the screw compressor of another embodiment. The principal part enlarged view of the screw compressor of another embodiment. Sectional drawing of the screw rotor of the direction orthogonal to an axis | shaft.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a screw compressor 10 (hereinafter simply referred to as a compressor 10) according to the present invention.

  The compressor 10 includes a main casing 11, a compressor main body cap portion 12, and a motor cap portion 13. The compressor 10 constitutes a casing by arranging and connecting a compressor main body cap portion 12, a main casing 11, and a motor cap portion 13 in this order.

  The main casing 11 includes a main casing main body 14 and a casing end cover 15.

  As shown in FIG. 2, the main casing main body 14 of the main casing 11 is formed with a convex portion 14a that protrudes in the axial direction inside the cap portion 12 for the compressor main body, and the end surface of the convex portion 14a has an axial direction. A rotor chamber recess 16 formed in the shape of a recess is provided. A first screw rotor (male screw rotor) 42 and a second screw rotor (female screw rotor) 43 described later are rotatably accommodated in the rotor chamber recess 16.

  A motor chamber recess 17 formed in a recess shape in the axial direction is provided on an end surface of the main casing body 14 on the motor cap portion 13 side. The motor chamber recess 17 accommodates a rotor 66 and a stator 67 of a motor unit 73 described later.

  A through hole 18 is provided coaxially with the first screw rotor 42 between the rotor chamber recess 16 and the motor chamber recess 17.

A first recess 19 that is coaxially arranged with the through hole 18 and has a larger diameter than the through hole 18 is provided on the back end surface of the motor chamber recess 17. The first recess 19 has an inner diameter of the first bearing arrangement portion 20 for arranging the first bearing 69 (roller bearing) to be described later is D _M. A locking groove 23 is provided on the inner peripheral surface of the first bearing arrangement portion 20 to lock the regulating member 22 for regulating the movement of the first bearing 69 toward the motor chamber recess 17 side.

A second recess 24 that accommodates a motor-side rotor shaft 47 of a second screw rotor 43 described later is provided on the back end surface of the rotor chamber recess 16. The second recess 24 has an inner diameter _DF , a second bearing arrangement portion 25 in which a second bearing (roller bearing) 57 to be described later is arranged, and a second bearing arrangement that is continuous with the second bearing arrangement portion 25. The shaft end receiving portion 26 is smaller in diameter than the portion 25. The second bearing arrangement portion 25 is located closer to the rotor chamber recess 16 than the shaft end accommodation portion 26. A locking groove for locking the regulating member 27 for regulating the movement of the second bearing 57 toward the rotor chamber concave portion 16 side is formed on the inner peripheral surface of the second bearing arrangement portion 25 of the second concave portion 24. 28 is provided. The second recess 24 is disposed at a position different from the first recess 19 in the axial direction.

  A casing end cover 15 is coupled to the end surface of the convex portion 14 a of the main casing body 14 inside the compressor body cap portion 12. A rotor chamber 32 that rotatably accommodates the screw rotors 42 and 43 is formed by the rotor chamber recess 16 of the main casing body 14 and a part of the casing end cover 15.

The casing end cover 15 is provided with two through holes 33 and 34 in the axial direction. Distance between the axes of the through holes 33, 34 is _{D CD.} The through hole 33 is arranged coaxially with the first screw rotor 42. The through hole 34 is disposed coaxially with the second screw rotor 43. On the end surface of the casing end cover 15, a lid 41 that closes the through holes 33 and 34 is provided. The lid 41 is provided with a pressing portion 41 a that protrudes inside the through holes 33 and 34 and fixes a plurality of bearings 52, 53, 54, 55, 58, 59, and 60 described later.

  The compressor 10 includes a first screw rotor 42 and a second screw rotor 43 that engage with each other. The first screw rotor 42 and the second screw rotor 43 are rotatably accommodated in the rotor chamber 32.

  The first screw rotor 42 extends in the axial direction from the motor-side rotor shaft 46 provided so as to extend in the axial direction from the end surface 44 on the motor cap portion 13 side, and from the end surface 48 on the compressor body cap portion 12 side. And an end-side rotor shaft 50 provided at the end.

The second screw rotor 43 includes a motor-side rotor shaft 47 provided so as to extend in the axial direction from the end surface 45 on the motor cap portion 13 side, and an axial direction from the end surface 49 on the compressor body cap portion 12 side. And an end-side rotor shaft 51 provided to extend. Distance between the axes of the motor-side rotor shaft 46, 47, and the axial distance between the end side rotor shaft 50, 51 is a _{D CD,} respectively.

  The motor-side rotor shaft 46 of the first screw rotor 42 is inserted into the through hole 18 of the main casing body 14.

  The end side rotor shaft 50 of the first screw rotor 42 is accommodated in the through hole 33 of the casing end cover 15. A plurality of bearings 52, 53, 54, and 55 are disposed in the through hole 33 of the casing end cover 15. The end side rotor shaft 50 of the first screw rotor 42 is supported by a plurality of bearings 52, 53, 54, and 55.

  The motor-side rotor shaft 47 of the second screw rotor 43 is accommodated in the second recess 24 of the main casing body 14. A second bearing 57 is arranged in the second bearing arrangement portion 25 of the second recess 24. The motor-side rotor shaft 47 of the second screw rotor 43 is supported by the second bearing 57 in a state where the end portion is accommodated in the shaft end portion accommodating portion 26. In the second bearing 57, a part of the surface on the shaft end accommodating portion 26 side and the outer peripheral surface abut against the second bearing arrangement portion 25, and the restriction member 27 is engaged with the locking groove 28 of the second bearing arrangement portion 25. It is fixed by stopping.

  The end side rotor shaft 51 of the second screw rotor 43 is accommodated in the through hole 34 of the casing end cover 15. A plurality of bearings 58, 59, and 60 are disposed in the through hole 34 of the casing end cover 15. The end side rotor shaft 51 of the second screw rotor 43 is supported by a plurality of bearings 58, 59, 60.

  A suction section 62 for sucking gas from outside through a filter (not shown) is provided on the rotor chamber recess 16 side of the motor chamber recess 17. A discharge portion 63 for discharging the compressed gas compressed in the rotor chamber 32 is provided on the casing end cover 15 side of the rotor chamber recess 16.

  A motor chamber 65 in which a rotor 66 and a stator 67 for driving the first screw rotor 42 are disposed is provided in an internal space where the motor chamber recess 17 and the motor cap 13 are connected. ing. The motor chamber 65 accommodates a rotor 66 and a stator 67 disposed on the outer periphery of the rotor 66 at a predetermined interval. A stator 67 is fixed to the inner peripheral surface of the motor chamber 65. A motor shaft 68 is provided on the rotor 66 of the motor 64.

  A first bearing 69 is disposed in the first bearing disposition portion 20 of the first recess 19 of the main casing body 14. The motor shaft 68 is supported by a first bearing 69. The first bearing 69 is fixed by locking the restriction member 22 in the locking groove 23 of the first bearing arrangement portion 20.

  The motor shaft 68 is connected to the motor side rotor shaft 46 of the first screw rotor 42. The motor-side rotor shaft 46 of the first screw rotor 42 is supported by the first bearing 69 via the motor shaft 68. In the present embodiment, the motor shaft 68 and the motor side rotor shaft 46 of the first screw rotor 42 are integrally formed.

  A discharge port 70 that communicates with the discharge portion 63 of the rotor chamber 32 is provided on the axial end surface of the compressor body cap portion 12. Further, the axial end surface of the motor cap 13 has a suction portion 62 of the rotor chamber 32, a communication hole for communicating the suction portion 62 and the motor chamber 65 indicated by a broken line in FIGS. A suction port 71 that communicates via 65 is provided.

  The compressor 10 includes a compressor main body 72 and a motor unit 73. In FIG. 1, the compressor main body 72 is a right portion of a connecting portion 74 between the motor side rotor shaft 46 and the motor shaft 68 of the first screw rotor 42, and the motor portion 73 is a left portion. The motor unit 73 is a component necessary for driving the motor-side rotor shaft 46 of the first screw rotor 42 of the compressor body 72, and the compressor body 72 is other than the motor unit 73 of the compressor 10. It is a component part.

  The operation of the compressor 10 having the above configuration will be described.

  The first screw rotor 42 is driven by obtaining a rotational force by electromagnetic interaction between the stator 67 and the rotor 66 of the motor unit 73, whereby the second screw rotor 43 is driven. The motor unit 73 is controlled by a control device (not shown) via an inverter (not shown). The compressor 10 sucks gas from the outside into the compression space of the screw rotors 42 and 43 (the space in the rotor chamber 32) through the suction part 62. When the first screw rotor 42 and the second screw rotor 43 are engaged, the gas is compressed in the compression space, and the compressed gas is discharged from the discharge portions 63 of the screw rotors 42 and 43.

In the compressor 10 according to the present invention, the first recess 19 provided on the rotor chamber 32 side of the motor chamber 65 and the second recess 24 provided on the motor chamber 65 side of the rotor chamber 32 are different in the axial direction. Placed in position. Therefore, the outer diameter D _M of the first bearing 69 disposed in the first recess 19, the outer diameter D _F of the second bearing 57 disposed in the second recess 24, and the first and second screw rotors. (D _M + D _F ) × 1/2 ≧ D _CD can be established between the inter-center distances D _CD of 42 and 43, and D _M and D _F can be increased. Accordingly, a first screw rotor 42, in a geometry that is determined from the axial center-to-center spacing D _CD between the second screw rotors 43 disposed in parallel with the first screw rotors 42, a large load That is, a large-sized bearing can be advantageously arranged.

  In the part where the motor side rotor shaft 46 and the motor shaft 68 of the first screw rotor 42 are connected, a plurality of bearings are required to support a large load. The number of bearings can be reduced. Therefore, troubles when supporting with a plurality of bearings, for example, a problem that the load on some bearings is biased and the shafts cannot be supported by other bearings and the shafts are lifted are avoided or reduced. it can.

  By having the first concave portion 19 and the second concave portion 24, the shafts 47 and 68 can be easily inserted and the large bearings 57 and 69 can be fitted into the casing, which is effective for manufacturing the compressor 10. Further, maintenance such as replacement of the bearings 57 and 69 is facilitated.

  In addition, the compressor 10 concerning this invention is not limited to the structure of the said embodiment, A various change is possible. For example, as shown in FIG. 3, the first concave portion 19 may be formed to have a long axial length, and the two first bearings 69 and 69 may be disposed. If it does in this way, even if it is a heavy load exceeding the durable load in one bearing, it can be supported by two bearings. That is, as described above, it is possible to advantageously arrange a bearing having a larger size than in the past, and to reduce the number of bearings in a portion where the motor-side rotor shaft and the motor shaft of the screw rotor are connected. Although it can be mentioned as an effect of the screw compressor concerning this invention, the number of the bearings is not limited to one for every said site | part.

  In the case shown in FIG. 1, the motor-side rotor shaft 46 of the first screw rotor 42 is supported by the first bearing 69 via the motor shaft 68. Instead, for example, as shown in FIG. 4, the motor-side rotor shaft 46 of the first screw rotor 42 may be directly supported by the first bearing 69. In FIG. 4, a coupling 75 is interposed in a connecting portion 74 between the motor-side rotor shaft 46 and the motor shaft 68 of the first screw rotor 42.

DESCRIPTION OF SYMBOLS 10 Screw compressor 11 Main casing 12 Cap part for compressor main body 13 Cap part for motor 18 Through-hole 19 1st recessed part 24 2nd recessed part 32 Rotor chamber 42 1st screw rotor (male screw rotor)
43 Second screw rotor (female screw rotor)
44, 45 End surface 46, 47 Motor side rotor shaft 48, 49 End surface 50, 51 End side rotor shaft 57 Second bearing (roller bearing)
65 Motor chamber 66 Rotor 67 Stator 68 Motor shaft 69 First bearing (roller bearing)
72 Compressor main body 73 Motor part 74 Connection part _DM , _DF Bearing outer diameter D _CD center distance

Claims (1)

A compressor main body having a rotor chamber that rotatably accommodates a first screw rotor to be engaged and a second screw rotor arranged in parallel with the first screw rotor;
A motor unit having a motor chamber that houses a rotor having a motor shaft and a stator disposed on the outer periphery of the rotor;
A through hole is provided between the rotor chamber of the compressor body and the motor chamber of the motor unit,
In the screw compressor that connects the rotor shaft of the first screw rotor and the motor shaft of the motor unit through the through hole,
A first recess is provided on an end face of the motor chamber on the rotor chamber side and is coaxial with the through hole and has a larger diameter than the through hole.
The first recess, the motor-side rotor shaft of the first screw rotor, via the motor shaft connected to the motor side rotor shaft, or directly, a first roller bearing the outer diameter of D _M for supporting Arranged,
A motor-side rotor of the second screw rotor that is arranged at a position different from the first recess in the axial direction and is arranged coaxially with a motor-side rotor shaft of the second screw rotor on an end surface of the rotor chamber on the motor chamber side. Providing a second recess for receiving the shaft;
A second roller bearing having an outer diameter D _F (provided that the outer diameter D _F is different from the outer diameter D _M ) for supporting the motor-side rotor shaft of the second screw rotor is disposed in the second recess. ,
(D _M + D _F ) × 1/2 ≧ D _CD and D _M > D between the D _M , the D _F , and the inter-axial distance D _CD of the first and second screw rotors A screw compressor characterized in that _F is established.

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