JPH07208361A - Screw compressor having package - Google Patents

Abstract

PURPOSE:To suppress generation of oscillation and obtain a structure in which oscillations are hardly propagated by providing columns being in contact with a ground at back sides of frame feet on a back surface of a base, and equally distributing surface pressure to contact portions between the columns and the ground, and the contact portion the base and the ground. CONSTITUTION:A frame 2 is fixed to a base 11, so that load of a compressor main body 1 and an electric motor 3 is applied to the base 11 at foot abutting portions of the frame 2. Columns 12 are provided on the back side of the fixation portions of the feed of the frame 2 on a back surface of the base 11. Areas of the boot bottom surfaces are so set that surface pressure applied to the bottom surface of the column 12 is equalized to the pressure applied to a groun abutting portions of the base 11. The pressure applied to the foot bottom may be set larger considering the base 11 or elasticity of a rubber sheet 18 laid on a ground 17. The compressor main body 1 mounted on the base 11, the electric motor 3, the frame 2 fixing them, and auxiliary mechanisms are covered with a package 6 in the conventional manner to interrupt generated noises.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a structure in which vibration generated by a screw compressor body is not diffused in a package.
The present invention relates to a configuration suitable for a compressor with low vibration and noise.

[0002]

2. Description of the Related Art A screw compressor is a type of rotary compressor, and its vibration and noise are smaller than those of a reciprocating compressor having the same capacity. For this reason, screw type compressors have been widely used in recent years, centering on general-purpose air compressors. However, when observed in detail, the compression operation is a repetition of intermittent suction, compression, and discharge of a compression space called a working chamber, and the pressure fluctuation inside the bore serves as a vibration source to generate vibration and noise. . Therefore, although it is a rotary compressor, it is difficult to avoid vibration noise to some extent even with a screw compressor.

The compressor includes not only the compressor body and an electric motor for driving the compressor but also a number of auxiliary machines such as a heat exchanger, a fan and a power supply box for cooling the compressed gas. A screw compressor with a package is one that is easy to use, traps noise, and is packaged so that it is aesthetically pleasing.

Regarding the package, Japanese Patent Application Laid-Open No. 4-63989 describes a structure in which the exhaust noise of cooling air does not easily leak to the outside and the direction of the exhaust port can be selected. Further, Japanese Patent Application Laid-Open No. 4-228897 describes a package having both a cooling effect and compactness and its internal layout. Neither of the known examples mentions blocking or sound insulation of solid propagating sound caused by the compressor body.

[0005]

The noise directly generated from the screw compressor body is almost blocked even in the conventional package as described in the above-mentioned known example, and it is not so large as to cause a problem. However, the vibration generated in the screw compressor body propagates to the structural members such as the pedestal and the base, and the solid-borne sound generated when the vibration is converted into noise around the base and the package becomes a speaker. Account for a large percentage. Therefore, there is a problem that the effect of noise reduction, which is one of the roles of the package, is effective only for the noise directly emitted from the main body surface.

Further, the conventional base is as shown in FIG.
It is composed of a plate-shaped member 31 that serves as the bottom of the package, a reinforcing member 32, a member 33 that serves as legs, and the like. The contact between the base and the ground is limited to the four corners of the base or the end faces 34 of the leg portions 33 on the outer periphery of the base, and the other parts are not in contact with the ground. Therefore, the heavy compressor body 35 and the electric motor 36 near the center of the base can be regarded as a load applied to the base 31, which is a beam. The beam, that is, the base 31, is not only deflected by the load even when it is stationary, but also because the support is soft, there is no restraining force against the vibration force of the compressor body 35, and the compressor body 35 easily vibrates. Therefore, the generated large vibration is also propagated to the package. That is, there is a problem that the structure of the base 31 enhances solid-borne sound.

The object of the present invention is to suppress vibration generated by the screw compressor main body, realize a structure in which the generated vibration is difficult to propagate to the package, reduce solid-borne noise, and have a package with less vibration and noise. To realize a screw compressor.

[0008]

In order to achieve the above object, the present invention uses the following means.

The screw compressor main body and the electric motor which is the drive source thereof are arranged approximately up and down, and the rotating shafts are connected by a conductive member such as a belt, a chain, a gear, and a coupling. At this time, the vertical relationship between the compressor body and the electric motor does not matter. Both the compressor body and the electric motor are fixed to the same frame. When the conductive member is a component such as a belt or a chain that needs to be adjusted in tension, the adjustment mechanism is also provided on this pedestal. Since the base is fixed on the base, the load of the compressor body and the electric motor is applied to the base at the part corresponding to the foot of the base. A support is provided on the back of the base at a position approximately behind the fixed position of the foot of the pedestal. Alternatively, the pedestal and the support are fixed through a member having sufficiently high rigidity. The height of the pillar is such that the lower side of the pillar is in contact with the ground, and the foot of the pillar is provided in the contact portion with the ground, and a certain area is secured to contact the ground.

The area of the sole of the foot is determined so that the surface pressure applied to the sole of the support pillar is substantially equal to the surface pressure applied to the portion of the base in contact with the ground. Alternatively, the surface pressure applied to the sole may be slightly increased in consideration of the elasticity of the base and the rubber sheet laid on the ground.

The compressor main body and the electric motor mounted on the base, the pedestal to which they are fixed, and the auxiliary machinery are covered with a package in the same manner as in the conventional case, and the direct noise generated by them is blocked.

[0012]

[Operation] Most of the static load of the pedestal to which the compressor body and the electric motor are fixed is not applied to the base but is applied to the column. Therefore, the deflection of the base when stationary is smaller than that of the conventional example. Since the compressor body and the electric motor are rigidly supported during operation, the vibration amplitude is small even if the vibration force generated in the compressor body is the same, and the force applied to the base is small There is also relatively little propagation of vibrations to the base. As a result, the vibration propagated to the periphery of the base and the package is small, and thereby the solid-borne noise generated from the surface of the package is also reduced.

On the ground on which the screw compressor with this package is installed, an elastic material such as a rubber sheet which can cause viscous deformation is often laid, and sinking due to a load is expected. If the surface pressure varies, the amount of subsidence will not be constant and the entire compressor may tilt. Even if it is not such an extreme situation, if the surface pressure applied to the legs of the stanchion is weaker than the others, there will be more sinking under the stanchion, and the load sharing will decrease in the direction in which the stanchion floats in the air. Then, the effect of the support is lost, and it becomes easy for vibration to propagate. However, in the present invention, the surface pressure applied to the column is made substantially equal to that of the other portions so that the amount of depression is approximately the same, and this problem is unlikely to occur.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of a screw compressor with a package of the present embodiment, and FIG. 2 is a perspective view from below.

The screw type compressor main body 1 is fixed to a pedestal 2 and has a capability of sucking, compressing and discharging gas by rotating a screw rotor therein by receiving rotational power on a rotor shaft. The pipes of the suction and discharge passages are not directly related to this embodiment, and therefore illustration and description thereof will be omitted.
The electric motor 3 is fixed to the electric motor stand 4 and receives electric power to generate rotational power. Power lines are also not directly related to the present embodiment, and therefore illustration and description thereof are omitted. The rotating shafts of the electric motor 3 and the compressor body 1 are connected by a belt 5. The tension of the belt 5 is adjusted by moving the motor base 4 up and down, and after the adjustment is completed, the motor base 4 is firmly fixed to the frame 2.

The base 11 is made by bending and welding an iron plate. The column 12 is fixed to the back of the base 11 at a position just behind the fixed portion of the gantry 2. The column 12 has a box shape and has the same height as the leg portion 13 of the base. The lower ends of the columns 12 are provided with column legs 14 to increase the contact area with the floor. The pillar foot 14 may be formed by welding another member to the pillar 12, or may have a structure in which the lower end of the pillar 12 is bent. The base 2 and the column 12 are firmly fixed to the base 1 with through bolts.
Since it is fixed to 1, the load of the pedestal 2 is directly applied to the column 12. A reinforcing plate 15 is also welded to the back side of the base 11 for strengthening the rigidity.

The floor on which the packaged screw compressor 7 is installed is usually a concrete floor 17 or a rubber sheet 18 laid on it.

The screw compressor 7 with a package is provided with auxiliary components such as a cooling fan 8 in addition to the main body 1 and the electric motor 3, and the package 6 covers all of them. The package 6 is fixed to the base 11 or a frame raised from the base 11.

The present embodiment operates as follows.

The main body 1 of the compressor and the electric motor 3 are particularly heavy members among the members constituting the main compressor 7, and are the members that generate the most vibration. The static load applied to the pedestal 2 fixing these is large, but most of the static load is not applied to the base 11 but to the support column 12. Therefore, the base 1 at rest
The deflection of No. 1 is smaller than that of the conventional example shown in FIG.

During operation, the compressor body 1 and the electric motor 3 are rigidly supported as compared with the conventional example, so that the vibration amplitude is small even if the vibration force generated in the compressor body is the same. Also,
Since the force applied from the gantry 2 to the base 11 is small, the generated vibration is transmitted to the base relatively little. In particular, since the base 12 is plate-shaped, it is soft against vibration in the vertical direction and is hard to propagate. As a result, the vibration propagating to the legs 13 of the base and the package 6 is small, and the solid-borne noise generated from the surface of the package 6 is also reduced.

When the screw compressor with the package 7 is installed, the rubber sheet 18 is elastically deformed and sinks due to the load. Further, it is expected that the rubber sheet 18 will be plastically deformed due to aging and will further sink. Rubber sheet 18
If there is variation in the surface pressure of the base leg 13 and the foot 14 of the column that touch the base, the amount of subsidence will not be constant, the compressor will tilt, and the load sharing will decrease in the direction in which the leg 14 of the column floats in the air. However, there is a concern that the effect of the column 12 will be lost and vibration will be easily propagated. However, in this embodiment, since the surface pressures to be set are almost equal to each other, the amount of subsidence is set to the same level, and this problem does not occur.

According to the present embodiment, it is possible to realize a compressor that reduces the propagation of vibrations and has a low noise without significantly changing the structure of the conventional compressor. Also, since there are few design changes, it is possible to modify the compressor in operation and expect the same effect.

In the present embodiment, the column 12 is constructed in the shape of a box, but it may have another shape, for example, an X-shaped column 19 as shown in FIG.

A second embodiment of the present invention will be described with reference to FIG. It should be noted that description of parts and functions common to those of the first embodiment will be omitted.

FIG. 4 is a sectional view of this embodiment. The pedestal 2 on which the compressor body 1 and the electric motor 3 are mounted is coupled to a support beam 21 fixed on a base 11. The support beam 21 has a rigidity sufficiently larger than that of the base 11 in the bending direction. The length of the support beam is longer than the fixed distance between the gantry 2 and the support beam 21, and the support column 21 is fixed to the support beam 21 by a bolt that penetrates the base 11 from the backside direction outside the fixed position.

The operation of this embodiment is the same as that of the first embodiment, but since the columns are widened, the structure for supporting the weight of the compressor body 1 and the electric motor 3 becomes more stable. Therefore, it is possible to further suppress the occurrence of vibration.

Although the support beam 21 is provided on the front side of the base 11 in this embodiment, it may be provided on the back side. Further, as shown in FIG. 5, a support member 22 in which the support column 12 and the support beam 21 are integrated with each other.
May be fixed to the back side of the base 11. In this case, since a simple modification of adding the support member 22 to the conventional base is required, it is a preferable method for reducing the vibration and noise of the compressor in operation.

[0029]

The screw compressor with a package according to the present invention supports the compressor main body and the electric motor, which have a large weight and an exciting force among the constituent members, with high rigidity with respect to the ground. The effect of this structure is to suppress the generated vibration amplitude, reduce the propagation of vibration, and reduce the solid-borne sound generated from the package surface. Therefore, a low noise compressor can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a perspective view from below of the first embodiment of the present invention.

FIG. 3 is a perspective view of another example of the pillar shape of the present invention.

FIG. 4 is a sectional view of a second embodiment of the present invention.

FIG. 5 is a sectional view of an application example of the second embodiment of the present invention.

FIG. 6 is a sectional view of an example of a conventional technique.

[Explanation of symbols]

1 ... Screw compressor main body, 2 ... Stand, 3 ... Electric motor, 4
... electric motor stand, 5 ... belt, 6 ... package, 7 ... screw compressor, 8 ... cooling fan, 11 ... base, 12 ... prop, 13 ... base leg, 14 ... prop foot, 17 ... concrete ground, 18 … Rubber sheet.

Claims (1)

[Claims] 1. A screw compressor main body and an electric motor for driving the screw compressor are arranged on the same base and housed in the same package. The screw compressor main body and the electric motor Are arranged above and below and fixed to the same pedestal, the pedestal is placed on the base, and the weight of the screw compressor main body and the electric motor is supported by the feet of the gantry that is a fixed portion of the pedestal and the base. A structure in which a pillar that contacts the ground is provided at a position on the back surface of the base approximately on the back side of the foot of the gantry, and the surface pressure of the contact portion of the pillar with the ground is the surface pressure of the contact portion of the base with the ground. A screw compressor with a package characterized in that the pressure is almost equal to the pressure.