JPH0315687A - Screw compressor - Google Patents

Abstract

PURPOSE:To avoid interference of a rotor bearing with a piston and place them up and down in parallel to shorten an axial dimension of a screw compressor by deviating the center line of a piston for driving the capacity adjusting valve of an ejecting gas apart from the center line of a screw rotor. CONSTITUTION:A pair of male and female screw rotors 3 are stored rotatably through each of bearings 5, 6, inside a casing 2. And a slide valve 9 for adjusting an ejection capacity is arranged on the ejecting side of the screw rotors 3, and connected to a piston 11 through a rod 10. ln this occasion, the rod 10 and the piston 11 are mutually connected with their center lines 11, 12, deviated from each other. Thereby, it is possible to avoid mutual interference between respective circumferences of the bearing 5 and the piston 11 so as to shorten the length of the rod 10 and the axial dimension of the device main body, since they can be place up and down in parallel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a screw compression device, and particularly to a screw compression device whose axial dimension can be designed compactly.

[Conventional technology]

Generally, a screw compression device is known in which a pair of male and female screw rotors housed in a casing are rotated in a direction in which they mesh with each other to compress suction gas.

As shown in FIG. 3, this type of rotor has a casing 22 in which a pair of male and female screw rotors 23 are rotatably housed via bearings 25 and 26. On the discharge side of this screw rotor 23 is a slide valve 2 that slides in the axial direction to adjust the discharge capacity.
9 is provided, and this slide valve 29 is driven via a piston 31 connected by a rod 30.

This piston 3l is housed in a cylinder 32, and this cylinder 32 is fixed to a discharge casing 33. Further, the slide valve 29 is driven by the operation of a piston 31, and the piston 31 is driven by supplying and discharging hydraulic oil through a conduit 38 and a conduit 39 connected to the cylinder 32. .

[Problem to be solved by the invention]

By the way, according to the structure of this type of screw compressor,
Since the center line of the screw rotor 23 and the center line of the slide valve 29 and the rod 30 and piston 31 integrated therewith are parallel lines, the diameter of the bearing 26 that supports the details of the screw rotor 23 and the piston 31 When considering the diameter of the bearing 26, the outer circumferences of the bearings 26 and 26 interfere with each other.
There is a problem that the piston 31 and the piston 31 cannot be arranged side by side in the same plane.

Therefore, in the past, the length of the rod 30 connecting the slide valve 29 and the piston 31 was increased, and the bearing 26
The above-mentioned interference had to be avoided by not arranging the screw compressor and the piston 31 side by side in the same plane, but this had the problem of increasing the axial dimension of the screw compressor.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a screw compression device that solves the problems of the above-mentioned conventional techniques and can be designed with a compact axial dimension.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a casing;
A pair of screw rotors are housed in this casing and have their shafts supported by bearings and mesh with each other, and a screw rotor that is slidable in the axial direction on the wall of the casing in order to adjust the gas capacity of the gas discharged from the screw rotors. In a device equipped with a slide valve arranged and a piston connected to the slide valve via a rod to drive the slide valve, when connecting the piston and the rod, the center line of the piston is The screw rotor is connected eccentrically in a direction away from the center line of the screw rotor.

[For production]

According to the present invention, when the piston and the rod are connected, the piston is eccentrically connected in a direction in which the center line of the piston is moved away from the center line of the screw rotor, so that the outer circumference of the bearing and the outer circumference of the piston are No more interference,
The piston and the bearing can be arranged side by side without increasing the length of the rod, and the axial length of the screw compressor can be made compact.

〔Example〕

Hereinafter, one embodiment of a screw compression device according to the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 2 indicates a casing, and within this casing 2, a pair of male and female screw rotors 3 are mounted with bearings 5.
, 6, and is rotatably housed. A slide valve 9 is provided on the discharge side of the screw rotor 3 to adjust the discharge capacity by sliding in the axial direction, and this slide valve 9 is driven via a piston 11 connected by a rod 10. It has become. This piston 11 is the cylinder 12
The cylinder 12 is housed in a discharge casing 13 fixed to the casing 2.

In the screw compressor configured in this way, according to this embodiment, the center line l1 of the rod 10 and the piston 11
The center line l2 of the two is eccentrically connected to each other. The direction of this shift is such that the center line I2 of the piston 11 is shifted from the center line 13 of the screw rotor 3.
It is oriented in the direction away from the

Next, to explain the operation of this embodiment, an electric motor (not shown) is connected to the outer shaft end of the screw rotor 3, and when the screw rotor 3 is rotated, the suction gas is compressed and discharged. Ru. At this time, by sliding the slide valve 9 disposed on the discharge side in the axial direction, the discharge volume of the discharge gas is adjusted. This slide valve 9 is driven by the operation of a piston 11, and this piston 11 is driven by supplying and discharging hydraulic oil through a conduit 18 and a conduit 19 connected to the cylinder 12.

Incidentally, while the size of the bearing 5 that supports the shaft portion of the screw rotor 3 is determined by the design, the outer diameter of the piston 11 is also determined by the design. In terms of design, the outer circumferential portions of the two usually interfere with each other, making it impossible to arrange them side by side in the same plane as shown in the figure.

However, according to this embodiment, from the relationship in which these center lines l1 and center lines l2 are shifted, as is clear from FIG. 2, the outer periphery of the bearing 5 supporting the screw rotor 3,
The outer periphery of the piston 11 no longer interferes with each other, and the bearing 5 and the piston 11 can now be arranged vertically in parallel in the figure, which is extremely advantageous in terms of design, and unlike the conventional
There is no need to increase the length of the rod 10, and the axial dimension of the screw compressor can be made compact.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a casing, a pair of mutually meshing screw rotors housed within the casing and having their shaft portions supported by bearings,
In order to adjust the gas capacity of the gas discharged from the screw rotor, a slide valve is disposed on the wall of the casing so as to be slidable in the axial direction, and a rod is connected to the slide valve to drive the slide valve. When the piston is connected to the rod, the center line of the piston is eccentrically moved away from the center line of the screw rotor, so that the bearing and the piston are connected. Since they do not interfere with each other, the piston and the bearing can be arranged side by side without increasing the length of the rod, and the axial length of the screw compressor can be made compact.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the screw compression device according to the present invention, Fig. 2 is a front view showing the positional relationship between the bearing and the piston, and Fig. 3 is a longitudinal sectional view showing the conventional screw compression device. It is. 3... Screw rotor, 5... Bearing, 10...
Rod, l1... Piston, 11... Center line of rod, l2... Center line of piston, l3... Center line of screw row. Figure 1 Figure 2

Claims (1)

[Claims] 1. A casing, a pair of screw rotors that are housed in the casing and mesh with each other and whose shafts are supported by bearings, and a wall of the casing that has an axial direction in order to adjust the gas capacity of the gas discharged from the screw rotors. In a screw compression device comprising a slide valve slidably disposed on the slide valve and a piston connected to the slide valve via a rod to drive the slide valve, the piston and the rod are connected. A screw compression device characterized in that the pistons are connected eccentrically in a direction in which the center line of the piston is separated from the center line of the screw rotor.