KR20130037177A - Screw compressor - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a cantilever-type motor direct screw compressor having a vibration damping structure that can directly reduce vibration of the rotor shaft itself while making it difficult to generate an unbalanced force (unbalance force) during rotation of the rotor shaft. It is.
A screw compressor (1) having a screw rotor (41), a motor shaft (7) integrally formed with respect to the screw rotor (41) and cantilever supported on the screw rotor side, and a motor for rotating the motor shaft (7). to be. The screw compressor 1 is loosely coaxial with the motor shaft 7 along the inner surface of the rotor 5 in the space between the motor side end face 7a of the motor shaft 7 and the end member 10. The cylindrical member 43 which has been inserted and provided, and the weight 8 (vibration body) which is coaxially and loosely inserted and arranged coaxially with the motor shaft 7 inside the cylindrical member 43 are provided. The natural frequency of the cylindrical member 43 and the natural frequency of the rotor shaft 11 match.

Description

Screw Compressor {SCREW COMPRESSOR}

The present invention relates to a screw compressor.

The screw compressor of the electric motor direct structure has better energy conversion efficiency than that of the power transmission system through the drive belt. Moreover, in the screw compressor which employs the rotation speed control system using an inverter, the screw compressor of the direct connection structure of an electric motor is the mainstream. Here, for the purpose of cost reduction and mechanical loss reduction, the motor direct connection screw compressor of the cantilever system which does not provide a bearing on one side of a motor shaft is often used.

In the case of a cantilevered screw compressor, the rotor shaft system is usually designed so that a dangerous speed is well above the operating speed. However, in the screw compressor in which the excitation force of the pressure pulsation component is generated, the vibration of the rotor shaft system portion may increase at a rotation speed much lower than the dangerous speed (rotation speed) of the rotor shaft. In addition, when the higher order component of the vibration due to unbalance determined by the shaft rotational speed is largely output due to loosening of the rotor shaft system, the vibration of the rotor shaft system portion also increases at a rotational speed lower than the dangerous speed (rotational speed). have.

Here, as a method of reducing the vibration of a screw compressor, there exists a method by the vibration damping apparatus, such as a copper reducer using anti-vibration rubber, and the method of controlling the rotation speed of a rotor shaft so that the rotation speed area | region which a vibration becomes large may skip.

However, in the method using a vibration damping device such as a copper reducer, if the installation conditions of the anti-vibration rubber part are changed due to deterioration of rubber or loosening of the mounting, the resonance frequency of the rotor shaft system part is changed so that the vibration damping effect is not obtained. There is a problem. Moreover, in the case of the screw compressor which employs the rotation speed control system using an inverter, it cannot cope with the vibration in the whole rotation speed area in the dynamic reducer which has a damping effect only to a specific frequency.

On the other hand, in the method of controlling the rotational speed of the rotor shaft to skip the rotational speed area where the vibration increases, it is necessary to skip the rotational speed area around the rotational speed where the vibration increases in consideration of safety, which causes trouble in practical operation conditions. There is a case.

Regardless of the natural frequency of a screw compressor, there exists a method of patent document 1 as a method (a method which can reduce the vibration in the whole rotation speed area | region), for example. Patent Document 1 discloses a screw compressor characterized in that a rod-shaped body is protruded in a horizontal direction with respect to a motor casing, and a plate (mass body) having a hole having a relatively large margin is inserted into the rod-shaped body. have. According to this structure, a plate (mass body) displaces up and down by the vibration of a motor casing, the rod-shaped object which protruded in the motor casing and a plate (mass body) collide, and vibration energy is consumed, and the vibration of a motor casing is reduced. do.

Japanese Patent Application Publication No. 2003-343641

Here, in the case of the cantilever-type electric motor direct screw compressor, when the vibration of the rotor shaft system portion of the screw compressor becomes large, the vibration around the rotation of the rotor shaft becomes remarkably large, and the distance between the rotor and the stator of the electric motor is widened or narrowed. At this time, since the magnetic attraction force acting between the rotor and the stator is changed, not only the rotor but also the stator side is affected by the magnetic attraction force, and the motor casing in which the stator is installed is excited with the magnetic attraction force and vibrates. Thus, not only the rotor side but also the stator side of the electric motor vibrates, the rotor and the motor casing of the electric motor are vibrated softly, and the vibration grows, and the air supply field rotor and the stator may come into contact with each other. As a result, a situation may arise in which the stator side is damaged and it becomes difficult to continue operation.

As mentioned above, in the vibration reduction method of patent document 1, the vibration of a "motor casing" is reduced by the rod-shaped body which protruded in the motor casing, and the plate (mass body) which can be displaced in the up-down direction inserted in this, have. Therefore, the vibration of the rotor side does not increase by the action of the vibration of the motor casing. However, when the vibration of the rotor shaft of the screw compressor itself is large and becomes a vibration exceeding the allowable load of the bearing, for example, some vibration countermeasure is required for the rotor shaft itself of the screw compressor. In addition, when vibrating countermeasures are performed on the rotor shaft itself, the vibration countermeasures should be devised so that they do not act as an unbalanced force (unbalance force) during rotation of the rotor shaft.

Moreover, in the structure which consists of the rod-shaped object which protruded in the motor casing, and the plate (mass body) which can be displaced in the up-down direction inserted in this, the space which arrange | positions a rod-shaped body and a plate (mass body) can be secured outside the motor casing. It may be necessary and may be a limitation of the package layout of the compressor. It may also be a constraint for achieving heat balance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above fact, and an object thereof is a cantilever beam having a vibration damping structure capable of directly reducing vibration of the rotor shaft itself while making it difficult to generate an unbalanced force (unbalance force) during rotation of the rotor shaft. It is to provide a direct type screw compressor of the electric motor.

In order to achieve the above object, the present invention provides a screw rotor, a screw casing for accommodating the screw rotor, a motor shaft which is integrally formed with respect to the screw rotor and cantilevered on the screw rotor side, and which rotates the motor shaft. The motor includes a rotor fixed to an outer circumference of the motor shaft, a stator disposed outside the rotor, a motor casing to accommodate the rotor and the stator, and the motor side of the motor shaft. The end face is located on the screw rotor side rather than the motor side end face of the rotor, and the end member is fixed to the motor side end face of the rotor in coaxial with the motor shaft, and the motor side end face of the motor shaft. A cylindrical member that is roughly coaxial with the motor shaft and is loosely inserted and disposed along the inner surface of the rotor in the space between the end members; An inner side of the cylindrical member is further provided with a vibrating body coaxially and loosely disposed with the motor shaft, and the natural frequency of the cylindrical member is adapted to the frequency at which the rotor shaft composed of the screw rotor and the motor shaft resonates. It provides a screw compressor characterized in that.

According to this configuration, the vibration energy is dissipated by the collision between the cylindrical member, the stroke end (for example, the motor side end face of the motor shaft), and the vibrating body or the like against the bending vibration of the rotor shaft, and the rotor is dissipated. The vibration of the shaft is reduced. In addition, since the natural frequency of the cylindrical member is set to the frequency at which the rotor shaft resonates, when resonance occurs in the rotor shaft, a large vibration is excited in the cylindrical member portion, and the vibration of the vibrating body is promoted by this vibration. Vibration reduction performance by collision and friction is further improved.

In addition, since the cylindrical member and the vibrating body are disposed substantially coaxial with the motor shaft, an unbalanced force (unbalance force) at the time of rotation of the rotor shaft is unlikely to occur.

According to the present invention, it is possible to directly reduce the vibration of the rotor shaft itself while making it difficult to generate an unbalanced force (unbalance force) during the rotation of the rotor shaft.

BRIEF DESCRIPTION OF THE DRAWINGS The side cross-sectional schematic diagram which shows the screw compressor which concerns on 1st Embodiment of this invention.
2 is an enlarged view of a portion A of FIG. 1 and a cross-sectional view taken along line X-X thereof.
3 is a side cross-sectional schematic diagram showing a screw compressor according to a second embodiment of the present invention.
4 is an enlarged view of a portion B of FIG. 3 and a Y-Y cross-sectional view thereof.
Fig. 5 is a partially enlarged side sectional schematic view showing a modification of the screw compressor shown in Figs. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(1st embodiment)

FIG. 1: is a side cross-sectional schematic diagram which shows the screw compressor 1 which concerns on 1st Embodiment of this invention. FIG. 2 is an enlarged view of a portion A of FIG. 1 (FIG. 2A) and an X-X cross-sectional view thereof (FIG. 2B).

(Configuration of Screw Compressor)

As shown in FIG. 1, the screw compressor 1 is a screw compressor of the motor direct connection structure provided with the screw main body 2 and the motor part 30 (motor).

(Screw body part)

The screw body part 2 has the screw rotor 41 and the screw casing 12 which accommodates the screw rotor 41. As shown in FIG. The screw rotor 41 has a screw tooth 4 and a screw shaft 3 coaxial with the screw tooth 4 and integrally formed with respect to the screw tooth 4. The screw shaft 3 is supported by both the bearing 14 and the bearing 15 at both sides.

The screw tooth 4 and the screw shaft 3 are manufactured by cutting etc. from one steel material. In addition, you may produce the screw tooth part 4 and the screw shaft 3 separately, and may also be steel-joint (integral connection). In addition, both the screw rotor 41 and the motor shaft 7 mentioned later are manufactured from one steel material by cutting, etc., and are integral structure. The rotor shaft 11 which rotates with the screw rotor 41 and the motor shaft 7 which are integrally structured with each other is comprised. In addition, you may produce the screw rotor 41 and the motor shaft 7 separately, and may also be steel-joint (integral connection). As a method of hard welding (integral structure), a flange connection etc. are mentioned.

(Motor part)

The motor part 30 (motor) is a drive source for rotating the rotor shaft 11, the rotor 5 fixed to the outer periphery of the motor shaft 7, and the stator arrange | positioned outside the rotor 5 6 and a motor casing 13 for receiving the rotor 5 and the stator 6. The motor shaft 7 is coaxial with the screw rotor 41 (screw shaft 3), becomes a unitary structure with respect to the screw rotor 41 (screw shaft 3), and supports cantilever on the screw rotor 41 side. It is. Specifically, the motor shaft 7 is cantilevered by the bearing 14 (and the bearing 15) on the screw rotor 41 side.

The motor side end surface 7a of the motor shaft 7 is located in the screw rotor 41 side rather than the motor side end surface 5a of the rotor 5. The disk-shaped end member 10 is fixed to the motor side end surface 5a of the rotor 5 with a bolt (not shown) or the like. A hole 10a is formed in the center of the end member 10. The end member 10 is coaxial with the motor shaft 7.

(Dust removal mechanism)

The cylindrical member 43 is inserted in the space between the motor side end surface 7a and the end member 10 of the motor shaft 7. The cylindrical member 43 is coaxial with the motor shaft 7 and is loosely inserted into the rotor 5, the end member 10, and the motor shaft 7, along the inner surface of the rotor 5. have.

The length of the cylindrical member 43 is smaller than the distance between the motor side end surface 7a and the end member 10. The axially movable amount of the cylindrical member 43 is, for example, about 0.5 mm to several mm. In addition, the outer diameter of the cylindrical member 43 is smaller than the inner diameter of the rotor 5. The axial orthogonal displacement possible amount of the cylindrical member 43 becomes about the same as the fitting dimension of the rotor 5 and the stator 6, for example, about 0.02 mm-about 0.5 mm.

Moreover, the bolt 9 is being fixed to the motor side end surface 7a of the motor shaft 7 coaxial with the motor shaft 7 (to the rotation center of the motor shaft 7). The bolt 9 arrange | positioned inside the rotor 5 is an example of the rod-shaped slide member which concerns on this invention.

As shown in FIG. 2A, the bolt 9 penetrates the motor side end surface 7a of the motor shaft 7 in a form penetrating the hole 10a formed in the center of the end member 10. It consists of the to-be-slid moving shaft part 16 and the head part 17 (large diameter part) formed in the edge part of the to-be-slid moving shaft part 16. As shown in FIG. The outer diameter of the head portion 17 is larger than the shaft diameter of the sliding shaft portion 16. The shaft diameter of the sliding shaft portion 16 is smaller than the shaft diameter of the motor shaft 7.

Here, inside of the cylindrical member 43, the several plate-shaped and annular weight 8 is accommodated in the state loosely inserted in the sliding shaft 16 of the bolt 9. As shown in FIG. In this embodiment, although it is set as six weights 8, it is not limited to six sheets. One piece may be sufficient. The weight 8 is an example of the plate-shaped annular body (vibration body) in this invention.

The total thickness of the six weights 8 is smaller than the distance between the motor side end surface 7a and the end member 10. In other words, the weight 8 is movable in the axial direction of the motor shaft 7. The axially movable amount of the weight 8 becomes about 0.5 mm-several mm, for example. In addition, the outer diameter (diameter) of the weight 8 is smaller than the inner diameter of the cylindrical member 43. In addition, as described above, since the weight 8 is loosely inserted into the sliding shaft portion 16 of the bolt 9, the weight 8 can also be moved (displaced) in the direction perpendicular to the axis of the motor shaft 7. . The axial orthogonal displacement possible amount of the weight 8 becomes about the same as the fitting dimension of the rotor 5 and the stator 6, for example, about 0.02 mm-about 0.5 mm.

Here, in FIG. 2A, the weight 8 is shown coaxial with the motor shaft 7. However, in a state where the weight 8 is loosely inserted into the slide shaft 16 of the bolt 9 and stopped, the amount of displacement of the weight 8 in the orthogonal direction of the weight 8 is approximately (0.02 mm to 0.5 mm). As a result, the shaft center of the weight 8 is lowered in the vertical direction than the shaft center of the motor shaft 7. In other words, in the present invention, the weight 8 (vibration body) is arranged coaxially with the motor shaft 7 in the " approximately " This represents the state where the axis of the weight 8 (vibration body) is lowered.

The same applies to the cylindrical member 43. In the present invention, the cylindrical member 43 is disposed coaxially with the motor shaft 7 in the " approximately " ), The shaft center of the cylindrical member 43 is lowered in the vertical direction than the shaft center of the motor shaft 7.

In this way, the weight 8 is substantially coaxial with the motor shaft 7 in the form of colliding with a member around the motor side end surface 7a of the motor shaft 7, the end member 10, and the like in the axial direction or the like. Is placed on. In the present embodiment, a plurality of weights 8 are used, so that they collide with each other in the axial direction.

In addition, although the cross-sectional shape of the sliding shaft part 16 is circular, it does not necessarily need to be circular, for example, square etc. may be sufficient. The same is true of the hole 8a formed in the center of the weight 8, and may be, for example, a rectangle instead of a circle. The shape of the hole 8a formed in the center of the weight 8 is matched with the cross-sectional shape of the sliding shaft 16. In addition, although the cross-sectional shape of the head part 17 is hexagon shape, it does not necessarily need to be hexagon shape, for example, circular shape etc. may be sufficient.

(Natural frequency of cylindrical member)

Here, the natural frequency of the cylindrical member 43 coincides with the natural frequency of the rotor shaft 11 constituted of the screw rotor 41 and the motor shaft 7. The natural frequency of the rotor shaft 11 is, for example, a component that rotates integrally with the rotor shaft 11, that is, the rotor shaft 11, the rotor 5, the bolt 9, and the end member 10. It calculates | requires by calculation considering components, such as these. The natural frequency of the cylindrical member 43 is adjusted by selecting the length, thickness, outer diameter, inner diameter, material, and the like.

(Action, effect)

According to the screw compressor 1, against the bending vibration of the rotor shaft 11 mainly caused by the rotation of the screw rotor 41, the cylindrical member 43 or the stroke end (motor of the motor shaft 7) before and after the axial direction When the side end face 7a and the end face of the end member 10] and the weight 8 (vibrator) collide or rub against each other, vibration energy is dissipated (dissipation of vibration energy due to axial collision), The vibration of the rotor shaft 11 is reduced. That is, the vibration of the rotating rotor shaft 11 itself can be directly reduced by the weight 8 colliding by moving in the axial direction or the like. Moreover, by arranging the weight 8 at the opposite end (near the end member 10) of the cantilever support side of the motor shaft 7, which is a part where the bending vibration of the rotor shaft 11 becomes large, The dissipation efficiency of vibration energy is made higher.

In addition, by matching the natural frequency of the cylindrical member 43 with the natural frequency of the rotor shaft 11, in the vicinity of the natural frequency of the rotor shaft 11, a large vibration is excited in the cylindrical member 43 part, and this vibration As a result, vibration of the weight 8 (vibration body) is promoted, and vibration reduction performance due to collision and friction is further improved.

Moreover, since both the cylindrical member 43 and the weight 8 (vibration body) are arrange | positioned substantially coaxially with the motor shaft 7, the imbalance force (unbalance force) at the time of rotation of the rotor shaft 11 is hard to generate | occur | produce. In addition, the weight 8 (vibration body) is loosely inserted into the bolt 9 arranged coaxially with the motor shaft 7 so that an unbalanced force (unbalance) during rotation of the rotor shaft 11 is obtained. It is difficult to generate. Furthermore, since the weight 8 is a plate-shaped annular body and the center of gravity of the weight 8 is the center of the axis of the weight 8, an unbalanced force (unbalanced force) is less likely to occur.

Moreover, since the some weight 8 is arrange | positioned adjacent to an axial direction, vibration energy is dissipated also when weight 8 collides in an axial direction or rubs with each other.

Moreover, by accommodating the cylindrical member 43 and the weight 8 in the space between the motor side end surface 7a of the motor shaft 7 and the end member 10, the axial length of the whole screw compressor is made into substantially the same as before. It is possible to do the same.

Moreover, what is necessary is just to match the natural frequency of the cylindrical member 43 with the frequency (the frequency to add attenuation with respect to the rotor shaft 11) which the rotor shaft 11 resonates. That is, although it is preferable to match the natural frequency of the cylindrical member 43 with the natural frequency of the rotor shaft 11, this is an example, and necessarily the natural frequency of the cylindrical member 43 to the natural frequency of the rotor shaft 11 is necessary. There is no need to match the frequency. When the natural frequency of the cylindrical member 43 is adjusted to the frequency at which the rotor shaft 11 resonates (the frequency to add attenuation to the rotor shaft 11), if resonance occurs in the rotor shaft 11 (attenuation is When vibration of the frequency to be added occurs on the rotor shaft 11], a large vibration is excited in the cylindrical member 43 portion, and the vibration of the weight 8 is promoted by this vibration, thereby reducing vibration caused by collision and friction. Performance is improved.

The frequency at which the rotor shaft 11 resonates is the frequency at which the bending vibration of the rotor shaft 11 increases in a specific vibration mode, and includes the natural frequency of the rotor shaft 11. In addition, the frequency to which attenuation is added with respect to the rotor shaft 11 is the frequency by which the bending vibration of the rotor shaft 11 which causes trouble in the operation of the screw compressor 1 becomes large, and the natural frequency of the rotor shaft 11 is increased. It includes.

In the screw compressor 1 described above, one end of the bolt 9 is fixed to the motor end surface 7a of the motor shaft 7 by twisting or the like, and the other end of the bolt 9 (head portion). (17)] is firmly in contact with the end member 10, the bolt 9 is supported on both sides, but only the end of the bolt 9 is fixed to the motor side end surface 7a, or the bolt is attached to the end member 10. The bolt 9 may be cantilever-supported, such as to fix only the end portion (head portion 17) of (9).

(Second Embodiment)

3 is a side sectional schematic diagram showing a screw compressor 102 according to a second embodiment of the present invention. 4 is an enlarged view of portion B of FIG. 3 (FIG. 4A) and a Y-Y cross-sectional view thereof (FIG. 4B). In FIG. 3 and FIG. 4, the same code | symbol is attached | subjected about the member similar to the screw compressor 1 of 1st Embodiment.

The main difference between the screw compressor 1 of the first embodiment and the screw compressor 102 of the present embodiment is the plurality of spherical bodies 44 as the vibrating body in the screw compressor 102 of the present embodiment. Is using.

(Sphere shape)

In the space between the cylindrical member 43 and the bolt 9, a plurality of spherical bodies 44 are loosely inserted and arranged. One spherical body 44 is disposed in the radial direction of the rotor shaft 11 on one side of the bolt 9. In this way, the plurality of spherical bodies 44 are arranged one layer in a layer form along the axial direction of the rotor shaft 11 on one side of the bolt 9. In addition, the plural spherical bodies 44 are arranged in layers four layers around the bolt 9. However, it does not necessarily need to be the fourth floor.

Similarly to the weight 8 of the first embodiment, the axially movable amount of the spherical body 44 is, for example, about 0.5 mm to several mm, and the axial orthogonal displacement possible amount is, for example, about 0.02 mm to about 0.5 mm. In such a form, the plurality of spherical bodies 44 are formed with a small gap therebetween, and are disposed substantially coaxially with the motor shaft 7 as a whole.

In addition, similar to the first embodiment, the natural frequency of the cylindrical member 43 is matched with the natural frequency of the rotor shaft 11, for example.

(Action, effect)

Similarly to the screw compressor 1 of the first embodiment, according to the screw compressor 102, the spherical body 44 (with respect to the bending vibration of the rotor shaft 11 mainly caused by the rotation of the screw rotor 41) ( Vibrating bodies) to collide with each other, to rub against each other, or to form a cylindrical member 43 or a stroke end before and after the axial direction (end surface of the motor side end face 7a and end member 10 of the motor shaft 7) and the like. When the upper body 44 (vibrating body) collides or rubs against each other, vibration energy is dissipated, and vibration of the rotor shaft 11 is reduced. That is, the vibration of the rotating rotor shaft 11 itself can be directly reduced by the spherical body 44.

In addition, when the natural frequency of the cylindrical member 43 matches the natural frequency of the rotor shaft 11, in the vicinity of the natural frequency of the rotor shaft 11, a large vibration is excited in the cylindrical member 43 part, and this vibration As a result, vibration of the spherical body 44 (vibration body) is promoted, and vibration reduction performance due to collision and friction can be further improved.

In addition, since both the cylindrical member 43 and the spherical body 44 (as a whole, the spherical body 44) are substantially coaxial with the motor shaft 7, the imbalance force at the time of rotation of the rotor shaft 11 ( Unbalance force) is difficult to occur.

In addition, in this embodiment, the some spherical body 44 is arrange | positioned one layer in the layer form along the axial direction of the rotor shaft 11 in the one side of the bolt 9. In the space between the cylindrical member 43 and the bolt 9, two (double) or more spherical bodies 44 may be adjacent to each other in the radial direction of the rotor shaft 11 on one side of the bolt 9. As in the present embodiment, it is preferable that the plurality of spherical bodies 44 are arranged one layer in a layer form along the axial direction of the rotor shaft 11. As a result, an unbalanced force (unbalance force) at the time of rotation of the rotor shaft 11 becomes more difficult to occur.

If a commercially available ball (steel ball or the like), which is a mass production product, is used as the spherical body 44 (vibrator), the cost can be reduced.

(Modified example)

In this embodiment, although the cylindrical member 43 is arrange | positioned and the spherical body 44 is 1 layer (per one side of the bolt 9) between the rotor 5 and the bolt 9, In the radial direction of the bolt 9, a layered spherical body 44 and a cylindrical member 43 are alternately stacked to form a laminated structure composed of a layered spherical body 44 and a cylindrical member 43. You may also

FIG. 5 is a partially enlarged side cross-sectional schematic diagram showing a modification of the screw compressor 1 shown in FIGS. 1 and 2, in which both (a) and (b) show a part of the screw compressor 1 (FIG. It is a figure corresponding to a).

In the modification shown in Fig. 5A, not only the cylindrical member 43 and the weight 8 are disposed in the space between the end member 10 and the motor side end surface 7a, but also the viscous body 24 is provided. I enclose it. By sealing the viscous body 24, viscous damping can be generated on the sliding surface of the weight 8, and as a result, the vibration of the rotor shaft 11 can also be reduced by this viscous damping. Here, the sliding surface of the weight 8 means the surface which the weight 8 and the sliding shaft 16 contact, the surface which the weight 8 and the cylindrical member 43 contact, etc. Examples of the viscous body 24 include high viscosity grease, silicone oil, and the like. The viscous body 24 having a viscosity of about 10000 cSt to 100000 cSt is preferable. In addition, also in the screw compressor 102 of 2nd Embodiment, not only arrange | positioning the cylindrical member 43 and the spherical body 44 in the space between the end member 10 and the motor side end surface 7a, The viscous body 24 may be enclosed.

In addition, as shown in FIG.5 (b), the disk-shaped weight 27 without a hole is a cylindrical member in the space between the end member 10 (no hole) and the motor side end surface 7a. A plurality of pieces may be inserted loosely along the inner surface of (43). That is, you may abbreviate | omit the bolt 9 shown to Fig.2 (a). Also with this form, the cylindrical member 43 and the stroke end (the motor side end surface 7a of the motor shaft 7 and the end surface of the end member 10) before and behind an axial direction, and the weight 27 (vibration body) By colliding with each other or rubbing each other, vibration energy is dissipated, and vibration of the rotor shaft 11 is reduced. In addition, by arranging a disk-shaped weight 27 approximately coaxial with the motor shaft 7, it is possible to make it difficult to generate an unbalanced force (unbalanced force) during rotation of the rotor shaft 11. In addition, the natural frequency of the cylindrical member 43 is adjusted to the frequency (for example, the natural frequency of the rotor shaft 11) to which attenuation is to be applied with respect to the rotor shaft 11, and thus the frequency of the frequency to which attenuation is to be added. When vibration occurs, large vibration is excited in the cylindrical member 43 part, and the vibration of the weight 27 is accelerated | stimulated by this vibration, and the vibration reduction performance by a collision and friction improves more.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, It can change and implement variously in the range as described in a claim.

1: screw compressor
2: screw body
3: screw shaft
5: rotor
6: stator
7: motor shaft
8: weight (vibration)
9: bolt (rod-shaped slide member)
10: end member
11: rotor shaft
12: screw casing
13: motor casing
30: motor part (motor)
41: screw rotor
43: cylindrical member

Claims (4)

With screw rotor,
A screw casing for accommodating the screw rotor,
A motor shaft integrally formed with respect to the screw rotor and supported on a screw rotor side with a cantilever beam;
A motor for rotating the motor shaft,
The motor includes:
A rotor fixed to an outer circumference of the motor shaft,
A stator disposed outside the rotor,
Having a motor casing to receive the rotor and the stator,
The motor side end face of the motor shaft is located on the screw rotor side than the motor side end face of the rotor,
An end member is coaxial with the motor shaft and fixed to the motor side end face of the rotor,
A cylindrical member disposed coaxially with the motor shaft and loosely inserted in the space between the motor side end surface of the motor shaft and the end member and being disposed along the inner surface of the rotor;
And a vibrating body disposed coaxially with the motor shaft and loosely disposed inside the cylindrical member,
The natural frequency of the said cylindrical member is set to the frequency with which the rotor shaft which consists of the said screw rotor and the said motor shaft resonates, The screw compressor characterized by the above-mentioned. The screw compressor according to claim 1, wherein the natural frequency of the cylindrical member and the natural frequency of the rotor shaft coincide with each other. The slide-shaped sliding member of claim 1 or 2, further comprising a rod-shaped sliding member having a shaft diameter smaller than that of the motor shaft which is disposed inside the rotor and is coaxial with the motor shaft.
The vibrating body is a screw compressor, characterized in that the plate-shaped annular body loosely inserted into the rod-shaped sliding member. The slide-shaped sliding member of claim 1 or 2, further comprising a rod-shaped sliding member having a shaft diameter smaller than that of the motor shaft which is disposed inside the rotor and is coaxial with the motor shaft.
The vibrating body is a screw compressor, characterized in that a plurality of spherical bodies loosely inserted between the cylindrical member and the rod-shaped sliding member.

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