KR20130037179A - Screw compressor - Google Patents

Abstract

PURPOSE: A screw compressor is provided to prevent the unbalanced force in the rotation of a rotor shaft, thereby directly reducing the vibration of the rotor shaft itself. CONSTITUTION: A screw compressor(1) comprises a screw rotor(41), a screw rotor(41), a motor shaft(7), a motor, and a dust-proof device unit. The screw casing receives the screw rotor. The motor shaft is formed into one body with the screw rotor and cantilever-supports in a screw rotor side. The dust-proof device unit includes a weight(8) of a plate shape in which arranged coaxially with the motor shaft. Natural frequencies of the weight are identical to that of a rotor shaft.

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. And a vibration damping mechanism portion including at least a plate-shaped weight disposed substantially coaxially with the motor shaft in a form of colliding with a motor or surrounding members or colliding with each other. A rotor compressor comprising a rotor and the motor shaft is adapted to a resonant frequency.

According to this configuration, the vibration energy is caused by additional collisions or frictions with the stroke ends (for example, the shaft ends of the motor shafts) and the like before and after the axial direction, or by collision of the weights with each other or friction with each other. Is dissipated, and vibration of the rotor shaft is reduced. In addition, since the natural frequency of the vibration damping mechanism portion including at least the weight is set to the frequency at which the rotor shaft resonates, the vibration of the vibration damping mechanism portion is promoted when resonance occurs in the rotor shaft, and vibration reduction performance due to collision and friction is achieved. This is further improved.

Moreover, since it is further arrange | positioned substantially coaxially with a motor shaft, the imbalance force (unbalance force) at the time of rotation of a rotor shaft hardly arises.

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 It is a side cross-sectional schematic diagram which shows the screw compressor which concerns on 1st Embodiment of this invention.
FIG. 2 is an enlarged view of portion A of FIG. 1 and a cross-sectional view taken along line X-X thereof. FIG.
3 is a view showing a modification of the weight shown in FIG.
It is a side cross-sectional schematic diagram which shows the screw compressor which concerns on 2nd Embodiment of this invention.
5 is an enlarged view of a portion B of FIG. 4 and a Y-Y cross-sectional view thereof.
It is a side cross-sectional schematic diagram which shows the screw compressor which concerns on 3rd Embodiment of this invention.
FIG. 7 is an enlarged view of portion C of FIG. 6 and a cross-sectional view taken along the line Z-Z.
8 is a partially enlarged side sectional schematic view of a screw compressor according to a fourth embodiment of the present invention.
9 is a partially enlarged side cross-sectional schematic diagram showing a modification of the screw compressor shown in FIGS. 1 and 2.
10 is a partially enlarged side sectional schematic view of the screw compressor according to the fifth embodiment of the present invention.
11 is a partially enlarged side cross-sectional schematic diagram showing a modification of the screw compressor shown in FIG. 10.

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 bolt 9 is fixed to the motor side end surface 7a of the motor shaft 7 coaxial with the motor shaft 7 (at the rotation center of the motor shaft 7). The bolt 9 is an example of the rod-shaped blood sliding 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, in the space between the motor side end surface 7a of the motor shaft 7 and the end member 10, a plurality of plate shapes are also annularly inserted in the state of being loosely inserted into the sliding shaft portion 16 of the bolt 9. The weight 8 of a shape is accommodated. In this embodiment, although it is set as six weights 8, it is not limited to six sheets. One piece may be sufficient. This weight 8 (in this embodiment, 6 sheets in total) and the bolt 9 constitute a vibration damping mechanism portion in the present 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 rotor 5. 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. That is, in the present invention, the weight 8 is arranged coaxially with the motor shaft 7 in the " approximately " It expresses that the axis of 로 comes down.

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.

In addition, in this embodiment, although the weight 8 is arrange | positioned at the opposite end (near the end member 10) of the cantilever support side of the motor shaft 7, the arrangement position of the weight 8 is not limited to this. For example, a rod-shaped sliding portion having an axial diameter smaller than the axial diameter of the rotor shaft 11 may be formed in the intermediate portion of the rotor shaft 11, and the weight 8 may be loosely inserted into this portion. .

(Natural frequency of vibration damping mechanism)

Here, the natural frequency of the weight 8 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 weight 8 is adjusted by selecting the plate thickness, diameter, material, and the like.

(Action, effect)

According to the screw compressor 1, the stroke end (motor side end surface 7a of the motor shaft 7) before and after an axial direction with respect to the bending vibration of the rotor shaft 11 mainly caused by the rotation of the screw rotor 41 is performed. And further colliding with each other and rubbing against each other, the vibration energy is dissipated (dissipation of the vibration energy due to the axial collision), and 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 can be made higher.

Moreover, by matching the natural frequency of the weight 8 which comprises the damping mechanism part with the natural frequency of the rotor shaft 11, the vibration of the weight 8 is accelerated | stimulated and the vibration reduction performance by a collision and friction can be improved more. It is supposed to be. This is because a large vibration is excited at the weight 8 portion near the natural frequency of the rotor shaft 11, so that collision and friction are promoted.

In addition, by arranging the weight 8 substantially coaxial with the motor shaft 7, an unbalanced force (unbalanced force) at the time of rotation of the rotor shaft 11 is unlikely to occur. Moreover, by making the shape which inserted the annular weight 8 loosely about the bolt 9 arrange | positioned coaxially with the motor shaft 7, the imbalance force (unbalance) at the time of rotation of the rotor shaft 11 is generated more. It is hard to let.

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 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 can be made substantially the same as before.

(Modified example)

The natural frequency of the bolt 9 and the natural frequency of the rotor shaft 11 constituted by the screw rotor 41 and the motor shaft 7 may coincide with each other. In the vicinity of the natural frequency of the rotor shaft 11, a large vibration is excited in the bolt 9 part, and a large vibration is excited also in the weight 8 part inserted loosely in the bolt 9 by the vibration. Thereby, the vibration reduction performance by collision and friction improves. The vibration of all the weights 8 can be promoted only by adjusting the natural frequency of one bolt 9. The natural frequency of the bolt 9 is adjusted by selecting the shaft diameter, length, material, and the like.

The natural frequency of the bolt 9 and the natural frequency of the weight 8 may both match the natural frequency of the rotor shaft 11. Furthermore, you may make the natural frequency of the vibration damping mechanism part comprised from the weight 8 and the bolt 9 (as a system) match with the natural frequency of the rotor shaft 11.

"The natural frequency of the damping mechanism part and the natural frequency of the rotor shaft 11 match" means that the natural frequency of at least one of the weight 8 and the bolt 9 and the rotor shaft 11 The natural frequency and the vibration damping mechanism part as a whole (as a system) include all of the natural frequency and the natural frequency of the rotor shaft 11 that match.

In addition, it is not necessary to necessarily match the natural frequency of the rotor shaft 11 with the natural frequency of the damping mechanism part. When the natural frequency of the vibration damping mechanism portion is adjusted to the frequency at which the rotor shaft 11 resonates (frequency to add attenuation to the rotor shaft 11), if resonance occurs in the rotor shaft 11 (attenuation to be added) When vibration of the frequency occurs in the rotor shaft 11], the vibration of the vibration damping mechanism part is promoted, and the vibration reduction performance due to collision and friction 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.

Furthermore, 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 By strongly contacting the portion 17 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 end member 10 The bolt 9 may be cantilevered as if only the end (head portion 17) of the bolt 9 is fixed.

(Variant example of weight)

3 is a diagram showing a modification of the weight 8 shown in FIGS. 1 and 2, and is a cross-sectional view of the weight corresponding to the cross-sectional view taken along line X-X shown in FIG. 2B.

As a premise, the natural frequency of the plate-shaped and ring-shaped weight 42 shown in FIG. 3 matches the natural frequency of the rotor shaft 11. As shown in FIG. 3, four crescent shaped holes 42b are formed in the peripheral part 42a of the weight 42 of this embodiment at equal intervals (same phase difference) along the circumferential direction. Part of the hole 42b has an arc shape along the outline of the weight 42.

Since the elasticity of the part becomes large by the presence of the hole 42b, the peripheral part 42a of the weight 42 becomes a spring part with a larger elasticity than the inner part of the said peripheral part 42a. Moreover, the slit which communicates the periphery of the said hole 42b and the weight 42 may be formed in the circular-arc top part of the crescent-shaped hole 42b, etc. As a result, a pendulum-shaped vibrating portion is formed in the peripheral portion 42a of the weight 42.

(Action, effect)

The mass and elasticity of the weight 42 are made by making the peripheral portion 42a of the weight 42 a spring portion having a greater elasticity than the inner portion of the peripheral portion 42a, and giving the peripheral portion 42a a function of a spring (elastic). It is easy to adjust the natural frequency of the weight 42 obtained from the equation.

In addition, by forming the plurality of holes 42b along the circumferential direction of the peripheral portion 42a to make the peripheral portion 42a a spring portion, the natural frequency of the weight 42 depends on the shape, dimensions, and the like of the hole 42b. Can be adjusted. Thereby, even when the frequency to which attenuation is to be added (for example, the natural frequency of the rotor shaft 11) is low, the natural frequency of the weight 42 can be adjusted while ensuring the plate thickness of the weight 42. Can be.

In addition, according to the weight 42 of the present embodiment, since the center of gravity of the weight 42 coincides with the center of the weight 42, an unbalanced force (unbalance force) also occurs during rotation of the rotor shaft 11. it's difficult.

(Second Embodiment)

4 is a side sectional schematic diagram showing a screw compressor 102 according to a second embodiment of the present invention. 5 is an enlarged view of a portion B of FIG. 4 (FIG. 5A) and a Y-Y cross-sectional view thereof (FIG. 5B). In FIG. 4 and FIG. 5, 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 that the screw compressor 102 of the present embodiment includes a cylindrical spacer 18.

(Spacer)

The spacer 18 is for adjusting the axially movable amount of the weight 8, and in this embodiment, it is arrange | positioned at the end member 10 side among the axial directions both sides of the weight 8. In addition, the spacer 18 can be arrange | positioned in at least one of the axial direction both sides of the weight 8. In addition, the number of the spacers 18 may be two or more.

By inserting the spacer 18, the axially movable amount of the weight 8 becomes about 0.5 mm-several mm, for example. In addition, the axial orthogonal displacement possible amount of the spacer 18 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. The hole 18a formed in the center of the spacer 18 may not be circular but may be rectangular, for example. The shape of the hole 18a formed in the center of the spacer 18 is matched with the cross-sectional shape of the sliding shaft 16.

(Action, effect)

If the axially movable amount of the weight 8 is too large, the weight 8 moves as if falling down, for example, and an unbalanced force (unbalanced force) during rotation of the rotor shaft 11 is generated. By adjusting the axially movable amount of the weight 8 by the spacer 18, the fall of the weight 8 can be prevented, and an unbalanced force (unbalanced force) is generated during rotation of the rotor shaft 11. It can be difficult.

(Third embodiment)

6 is a side sectional schematic diagram showing a screw compressor 103 according to the third embodiment of the present invention. FIG. 7 is an enlarged view of part C of FIG. 6 (FIG. 7A) and a Z-Z cross-sectional view thereof (FIG. 7B). In FIG.6 and FIG.7, 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 103 of the present embodiment is the arrangement of weights. In the screw compressor 103 of the present embodiment, the outer side of the screw member 103 of the screw compressor 103 of the first embodiment [ The weight is arrange | positioned to the axial direction outer side of the rotor 5].

(Dust removal mechanism)

The bolt 21 (rod-shaped sliding member) of this embodiment penetrates the motor side end surface 7a of the motor shaft 7 in the form which penetrates the hole 10a formed in the center of the end member 10. As shown in FIG. It consists of the to-be-slid | moved axial part 22 and the head part 23 (large diameter part) formed in the edge part of the slidable-movement axis part 22. As shown in FIG. The sliding shaft portion 22 has a small diameter portion 22a and a middle diameter portion 22b in order from the end face side of the motor shaft 7. The outer diameter of the head portion 23 is larger than the shaft diameters of the small diameter portion 22a and the middle diameter portion 22b of the sliding shaft portion 22 and larger than the inner diameter of the weight 20. By making the outer diameter of the head part 23 larger than the inner diameter of the weight 20, the weight 20 does not protrude from the edge part of the bolt 21 and fall off.

The head portion 23 of the bolt 21 is located outside the end member 10, in other words, outside the axial direction of the rotor 5. Although the cross-sectional shape of the head part 23 is a hexagon, it does not necessarily need to be a hexagon, For example, circular shape etc. may be sufficient.

A plurality of annular weights 20 are loosely inserted into the middle diameter portion 22b of the sliding shaft portion 22 between the head portion 23 of the bolt 21 and the end member 10. In the present embodiment, three weights 20 are used, but the number is not limited to three. One piece may be sufficient. These three weights 20 and the bolts 21 constitute a vibration damping mechanism portion in the present invention.

In the first embodiment described above, the natural frequency of the vibration damping mechanism portion composed of these three weights 20 and the bolts 21 is adjusted to the frequency to which attenuation is to be applied to the rotor shaft 11. Since it is the same as the compressor 1, the description is abbreviate | omitted (also in embodiment and modified example which are described later).

(Action, effect)

According to the screw compressor 103 of this embodiment, the weight 20 is arrange | positioned outside the edge part on the opposite side of the cantilever support side of the motor shaft 7 which is a part by which the bending vibration of the rotor shaft 11 becomes large, and an axial direction The dissipation efficiency of the vibration energy due to the collision can be further increased. According to the screw compressor 103, the weight 20 can be set without removing the end member 10. In addition, when adjusting the quantity of the weight 20, etc., basically, only the length of the middle diameter part 22b of the bolt 21 needs to be changed, and the machining of the motor shaft 7 (the length of the motor shaft 7 is changed). ] Is not required. In addition, the outer diameter dimension of the weight 20 can also be arbitrarily determined.

(Fourth Embodiment)

FIG. 8 is a partially enlarged side sectional schematic view of the screw compressor 104 according to the fourth embodiment of the present invention, which is a view corresponding to FIG. 2A showing a part of the screw compressor 1. In FIG. 8, the same code | symbol is attached | subjected about the member similar to the screw compressor 1 of 1st Embodiment.

In this embodiment, not only the weight 8 is arrange | positioned in the space between the end member 10 and the motor side end surface 7a, but the viscous body 24 is enclosed. 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 where the weight 8 and the sliding shaft 16 contact, the surface where the weight 8 and the rotor 5 contact, and the like. 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.

As a modification of the fourth embodiment, it is also preferable to enclose a granulated material that vibrates with vibration of the motor shaft 7 in the space between the end member 10 and the motor side end surface 7a. According to the encapsulation of the powder, the vibration of the rotor shaft 11 can be reduced even by friction damping caused by the friction between the particles of the powder. In addition, as a granulated material, slag (blast furnace slow cooling slag, blast furnace slag slag, converter slag, electric furnace slag, etc.), cold pellets (hardening iron, dust, fly ash, etc. to a pellet form by cement), metal-type reduced iron Pellets and sintered steel, glass-based siras balloons (fine hollow glass spheres based on volcanic ash), ceramic powders, and the like. A granule having a particle size of about 100 μm to several mm is preferable.

(Modified example)

FIG. 9 is a partially enlarged side cross-sectional schematic diagram showing a modification of the screw compressor 1 shown in FIGS. 1 and 2, and any view corresponds to FIG. 2A showing a part of the screw compressor 1. Drawing.

In addition to arranging a plurality of weights adjacently in the axial direction of the motor shaft 7, as shown in FIG. It is also preferable to arrange | position 25 * 26 adjacently (multilayer arrangement). The inner diameter of the annular weight 25 is larger than the inner diameter of the annular weight 26. By arranging the weights 25 and 26 adjacently (multilayer arrangement) in the axial orthogonal direction (diameter direction) of the motor shaft 7, the weights 25 and 26 are also collided and rubbed, so the collision and sliding area of the weight is also increased. This makes it easier to dissipate the vibration energy.

In this embodiment, it is also preferable to enclose the viscous body 24 and the granular material shown in FIG. 8 in the space between the end member 10 and the motor side end surface 7a. By enclosing the viscous body 24, viscous attenuation can also be generated on the sliding surfaces between the weights 25 · 26. By enclosing the granular material, the friction damping effect of the particles of the granular material rubs against each other is also obtained between the weights 25 · 26. In addition, in this embodiment, although two weights 25 * 26 are arrange | positioned adjacently (multilayer arrangement) in the axial orthogonal direction, you may arrange | position three or more weights adjacently (multilayer arrangement) in an axial orthogonal direction.

In addition, as shown in Fig. 9B, a plurality of disc-shaped weights 27 without holes may be arranged in a space between the end member 10 (no hole) and the motor side end surface 7a. do. That is, you may abbreviate | omit the bolt 9 shown to Fig.2 (a). Also in this embodiment, vibration energy is dissipated by the collision of the stroke end (motor side end face 7a of the motor shaft 7 and end face of the end member 10) before and after the axial direction with the weight 27, and the rotor The vibration of the 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 weight 27 is adjusted to the frequency (for example, the natural frequency of the rotor shaft 11) to which the attenuation is to be applied to the rotor shaft 11, so that the frequency of the frequency to which the attenuation is to be added. When the vibration occurs, the vibration of the weight 27 is promoted, and the vibration reduction performance due to the collision and friction is further improved.

(Fifth Embodiment)

FIG. 10 is a partially enlarged side cross-sectional schematic diagram of the screw compressor 105 according to the fifth embodiment of the present invention, which is a view corresponding to FIG. 2A showing a part of the screw compressor 1. In FIG. 10, the same code | symbol is attached | subjected about the member similar to the screw compressor 1 of 1st Embodiment (it is the same also about FIG. 11 mentioned later).

In the present embodiment, in the space between the end member 10 and the motor side end surface 7a, one annular weight 19, two coil springs 32, and an annular damping member 33 are provided. ) Two are placed. The two coil springs 32 are arranged in the space between the end member 10 and the motor side end surface 7a in a form inserted into the annular damping member 33 from the outside thereof. Furthermore, the two coil springs 32 are built in the contracted state, respectively, between the end member 10 and the weight 19, and between the weight 19 and the motor side end surface 7a. In this way, the annular weight 19 is supported in the axial direction by the coil spring 32 and the damping member 33. In addition, similarly to the weight 8 in the first embodiment, the fitting dimension of the outer circumferential surface of the weight 19 and the rotor 5 or the fitting dimension of the inner circumferential surface of the weight 19 and the bolts 9 are determined. By making it approximately the same as the fitting dimension of the rotor 5 and the stator 6, it becomes difficult to generate the unbalanced force (unbalanced force) at the time of rotor shaft 11 rotation. Here, as the damping body 33, the damping body of a silicone gel is mentioned, for example.

According to this embodiment, the weight 19 vibrates in the axial direction with respect to the vibration of the rotor shaft 11, and the vibration energy of the rotor shaft 11 is dissipated by the reaction force. That is, while making it difficult to generate the imbalance force (unbalance force) at the time of rotation of the rotor shaft 11, the vibration of the rotor shaft 11 can be directly reduced by the vibration damping action of the so-called copper reducer.

As a modification of the fifth embodiment, as shown in FIG. 11A, an annular convex leaf spring 35 may be used instead of the coil spring 32. Instead of the annular damping member 33, a viscous body 34 such as a grease having a high viscosity may be sealed in the space between the end member 10 and the motor side end surface 7a. As the viscous body 34, silicone oil etc. besides high grease are mentioned. The viscous body 34 having a viscosity of about 1000 cSt to 10000 cSt is preferable.

In addition, as shown in FIG. 11B, instead of the coil spring 32 and the damping member 33, between the end member 10 and the weight 19 and the weight 19 and the motor side end surface ( The annular viscoelastic body 36 may be arrange | positioned between 7a), and the weight 19 may be supported by the viscoelastic body 36 in the axial direction. As the viscoelastic body 36, it is preferable to use the high damping rubber (for example, butyl-type rubber | gum) of about 0.2-0.5 of a loss coefficient. In addition, although the some viscoelastic body 36 is arrange | positioned at the both sides of the weight 19 in this modification, you may arrange | position the viscoelastic body 36 one each at both sides of the weight 19. As shown in FIG.

In addition, although illustration is abbreviate | omitted, like the weight 27 shown in FIG.9 (b), the weight 19, the damping body 33, and the viscous body 34 shall be a form without a hole, The bolt 9 may be omitted.

Furthermore, for example, in the structure shown in FIG. 10, you may arrange | position the coil spring 32 and the damping body 33 only on one side among the both sides of the weight 19 (also in FIG. 11). On the side where the coil spring 32 and the damping member 33 are not arranged, vibration energy is dissipated by colliding with the weight 19 and the end member 10 (or the shaft end of the motor shaft 7).

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
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

Claims (7)

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,
And a vibration damping mechanism portion including at least a plate-shaped weight disposed substantially coaxially with the motor shaft in a form colliding with a surrounding member or colliding with each other.
The natural frequency of the said vibration damping mechanism part is set to the frequency with which the rotor shaft which consists of the said screw rotor and the said motor shaft resonates. The vibration damping mechanism unit further comprises a rod-shaped sliding member having a shaft diameter smaller than the shaft diameter of the motor shaft provided coaxially with the motor shaft.
Loosely inserted into the annular additional rod-shaped sliding member,
The natural frequency of at least one of the said ring-shaped weight and the said rod-shaped sliding member is matched with the frequency with which the said rotor shaft resonates, The screw compressor characterized by the above-mentioned. The peripheral part of the said weight is a spring part with a larger elasticity than the inner part of the said peripheral part,
The natural frequency of the said weight is set to the frequency with which the said rotor shaft resonates, The screw compressor characterized by the above-mentioned. The screw compressor according to claim 3, wherein a plurality of holes are formed in the peripheral portion in the circumferential direction of the peripheral portion so that the peripheral portion becomes the spring portion. The method of claim 1 or 2, wherein the motor,
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 coaxial with the motor shaft and fixed to the motor side end face of the rotor,
The said compressor is further accommodated in the space between the motor side end surface of the said motor shaft, and the said end member. The method of claim 3, wherein the motor,
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 coaxial with the motor shaft and fixed to the motor side end face of the rotor,
The said compressor is further accommodated in the space between the motor side end surface of the said motor shaft, and the said end member. The method of claim 4, wherein the motor,
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 coaxial with the motor shaft and fixed to the motor side end face of the rotor,
The said compressor is further accommodated in the space between the motor side end surface of the said motor shaft, and the said end member.

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