JPS5851287A - Screw type rotary compressor - Google Patents

Abstract

PURPOSE:To improve the performance of a screw compressor, by eliminating leakage of fluid at the region near the discharge opening of the compressor through employment of such an arrangement that rotor shafts are positioned with some displacement toward the discharge side from the axes of a rotor chamber. CONSTITUTION:Rotor shafts 6a, 6b of a female and a male rotors 5a, 5b are positioned such that the distance between them is kept constant but they are displaced slightly downward from the axes 7a, 7b of a rotor chamber 2 while keeping parallelism with the axes 7a, 7b. In operation, fluid handled by the compressor causes elastic deformation of the rotor shafts 6a, 6b in a direction away from a discharge opening 4. However, since arrangement is such that the rotor shafts 6a, 6b are positioned with some displacement toward the discharge opening 4, gaps 10a, 10b between the rotors 5a, 5b and the inner surface of the rotor chamber 2 at the region near the discharge opening 4 can be kept small, so that leakage of fluid can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a screw-type rotary machine that uses a pair of male and female screw rotors to suck in fluid, compress it, and then discharge it.

The screw rotor is constructed by housing the screw rotor in a rotor chamber of a casing having a suction port and a discharge port, and the circumscribed surface of the rotor tooth tip and the circumferential surface of the rotor chamber are formed into a substantially perfect circular shape. In this machine, the size of the gap between the outer circumference of the rotor and the inner circumference of the rotor is
Machine efficiency.

The effect on performance is extremely large, and it is necessary to maintain a certain clearance during operation.

For this reason, conventionally, the rotor shaft and the axial center of the rotor chamber are made to coincide with each other, and the above-mentioned gap is maintained to a certain extent for assembly.

However, when the machine is in operation, the fluid pressure increases toward the discharge port, so in the machine described above, the rotor shaft at the discharge port undergoes elastic deformation in a direction that spreads beyond the discharge port, and the gap becomes maximum. Also, since the rotor bearing has a slight gap in the axial direction, as the fluid pressure increases, the discharge port side lowers! This has the disadvantage that the gap on the end face side also expands, reducing the performance of the machine.

The present invention has been made in view of the above-mentioned conventional drawbacks, and attempts to provide a screw-type rotating machine with improved performance by assembling the rotor shaft with the rotor shaft deviated from the axis of the rotor chamber toward the discharge port side. It is something to do.

Next, the present invention will be explained with reference to the drawings, which are one embodiment.

1 and 2 show a screw-type rotating machine according to the present invention, in which 1 is a casing, inside which is a rotor chamber 2 consisting of two parallel cylindrical spaces partially copolymerized in the axial direction. The rotor chamber 2 has a suction port 3 on the top surface of one end of the overlapping portion and a discharge port 4 on the bottom surface of the other end.
have.

Further, within the rotor chamber 2, there is a pair of male and female screw rows 1 (hereinafter referred to as rotors) 5a that mesh with each other.

5b are housed therein, and these are connected to a rotational drive means (not shown) and are rotatable.

Further, the male and female rotors 5a, 5b have cross sections inscribed in a substantially perfect circle, and their rotational axes 6a, 6b have a constant distance between their axes as shown in FIG. , while being kept parallel to the axes 7a, 7b of the rotor chamber 2, and slightly deviated downward from the axes 7a, 7b.

Next, the operation of the screw type rotating machine having the above configuration will be explained.

As shown by the arrow A in Fig. 2, the male rotor 5
b is the drive side, rotors 5a rotating in mutually opposite directions;
5b, fluid is sucked into the rotor chamber 2 from the suction port 3, and a tooth groove portion 8a is formed by each rotor 5a, 5b and the inner peripheral surface of the rotor chamber 2.

Trapped in 8b.

The ends of the tooth grooves 8a, 8b on the suction port 3 side are closed by the meshing portions 9 of the rotors 5a, 5b, and the meshing portions 9 move toward the discharge port 4 as the rotors 5a, 5b rotate. (in the direction of arrow B in Figure 1).

On the other hand, the tooth groove portions 8a, gb at the discharge port 4 are closed by the end surface of the rotor chamber 2 on the discharge port side, and the position is constant, so the space within the tooth groove portions 8a, Bb contracts with the above movement, and the internal The fluid pressure increases as the discharge D 4 i approaches.

Then, the fluid pressure reaches the maximum at the discharge port 4, and the fluid flows through the rotor shafts 5a, 5. b in the direction expanding from the discharge port 4 (
While elastically deforming the discharge port 4 in the direction of arrows C and C in Fig. 2,
Go out more.

As mentioned above, the rotor shafts 5a, 5b are installed in advance so as to be slightly closer to the discharge port 4 than the rotor chamber axes 7a, 7b, so that the rotor shafts 5a, 5b in the portion of the discharge port 4 are
The gaps 10a, 10b between the rotor chamber 2 and the inner circumferential surface of the rotor chamber 2 can be kept to a small value.

On the other hand, since the gaps 10a and 10b are set in the opposite direction and in the expanding direction, the value is slightly larger, but compared to the fluid pressure at the discharge port 4, the fluid pressure near this area is Low and gap 10a.

Since the pressure difference between both sides of 10b is small, fluid leakage is small and there is no problem in terms of mechanical performance.

Incidentally, the deviation of the rotor shafts 5a, 51j is not limited to the above-mentioned example, but may be any deviation as long as at least the discharge port side of the rotor shafts 5a, 5b is brought closer to the discharge port 4.

For example, the rotor shafts 5a, 51] are set to the axis 7a of the rotor chamber 2.
, 7b, each axis 7a.

It is also possible to have the deflection parallel to 7b and bring them closer to each other (FIG. 4), or to combine this deflection with the deflection in the above embodiment (FIG. 5).

Alternatively, only the discharge port sides of the rotor shafts 5a and 5b are brought close to the discharge port 4 while keeping the distance between the shafts constant (Fig. 6).
, one in which the shafts are brought closer to each other in a plane including the axes 7a and 7b (Fig. 7), and one in which these are combined (
(Fig. 8) may be used.

As is clear from the above description, according to the present invention, the rotor shaft is assembled by being deviated from the axis of the rotor chamber toward the discharge port side. Therefore, the fluid pressure is maximum and the pressure difference on both sides of the gap between the rotor outer periphery and the rotor indoor circumferential surface is the largest (here, the above gap is kept at a small value and the gap is removed from the gap). can prevent fluid leakage and improve machine performance.

In addition, when only the discharge port side of the rotor shaft is deflected, the rotor shaft is elastically deformed in the direction of expanding from the discharge port, and the gap between the screw rotor end face and the rotor chamber circumferential surface is pinched, and the fluid is It has the effect of reducing leakage, etc.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a screw type rotating machine according to the present invention;
FIG. 2 is a sectional view taken along the line II in FIG. 1, and FIGS. 3 to 8 are explanatory diagrams showing the deviation state of the ronita shaft. 1...Casing, 2...Rotor chamber, 3.
...Suction port, 4...Discharge port, 5a, 5b...
・Screw rotor, 5a, 5b...rotor shaft,
7a, 7b... Axis center of rotor chamber. Patent applicant Kobe Steel Co., Ltd. Agent Patent attorney Aoyama Aoyama and 2 others ~ 0 Figure 7 σ3 ←C Figure 8 σ3

Claims (1)

[Scope of Claims] (1) A pair of male and female screw rotors that mesh with each other are housed in a rotor chamber of a casing, and a suction port is provided at one end of the rotor chamber above the meshing portion, and a discharge port is provided at the other end. forming an exit;
In a screw-type rotating machine that sends fluid from a suction port to a discharge port, each rotor shaft is offset from each axis of the rotor chamber so that at least the side of the discharge port approaches the discharge port. A screw-type rotating machine characterized by: (2) Claims characterized in that the above deviation causes each rotor shaft to approach the discharge port while keeping the distance between the shafts constant and parallel to the axis of the rotor chamber. Screw type (3) described in paragraph 1: The above deviation causes each rotor shaft to approach each other by ζ while keeping each rotor shaft parallel to each axis of the rotor chamber in a plane including each axis of the rotor chamber. A screw-type rotating machine according to claim 1, characterized in that the screw-type rotating machine is a rotary machine. (4) The above-mentioned deflection moves each rotor shaft toward the discharge port while keeping each rotor shaft parallel to each axis of the rotor chamber. The screw-type rotating machine described. (5) The above-mentioned deviation is such that only the side portions of the roller shafts approach the discharge port while keeping the roller shafts parallel to each other and the distance between the shafts constant. The screw-type rotating machine described in item 1. (6) The screw type according to claim 1, wherein the deviation is such that the rotor shafts approach each other only on the discharge port side within a plane including each axis of the rotor chamber. rotating machine. (7) The screw-type rotating machine according to claim 1, wherein the deflection moves only the discharge port side portion of each roller shaft toward the discharge port.