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Screw pump and screw gear

a screw gear and screw technology, applied in the field of screw gear, to achieve the effect of high degree of flexibility

Inactive Publication Date: 2009-01-15
TOYOTA IND CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a screw pump and screw gear with high flexibility in fluid compression. The screw gear has a portion where the lead angle is continuously changed from the leading end to the trailing end of a spiral groove. This is achieved by a combination of multiple change functions having different manners of changing the lead angle. The screw pump apparatus includes a pair of screw gears mating with each other and a pump chamber accommodating the screw gears. The screw gears rotate while mating with each other, transferring fluid in an axial direction while being compressed within the pump chamber. The actuation chamber for compressing the fluid is defined between adjacent thread ridge portions in the axial direction of each respective screw gear.

Problems solved by technology

However, in the case of changing the winding start lead angle DegS and the winding end lead angle DegE for changing the gas compression characteristic of the screw pump, there can be generated a case that the entire length L of the screw gear comes to a value by which the screw gear cannot be accommodated within the pump chamber.

Method used

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  • Screw pump and screw gear
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Examples

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Effect test

Embodiment Construction

[0020]A description will be given of one embodiment according to the present invention with reference to FIGS. 1 to 3B.

[0021]As shown in FIG. 1, a screw vacuum pump 11 in accordance with the present embodiment is provided with a cylindrical rotor housing member 12, a lid-shaped front housing member 13 jointed to a front end (a left end in FIG. 1) of the rotor housing member 12, and a plate-shaped rear housing member 14 joined to a rear end (a right end in FIG. 1) of the rotor housing member 12. A stepped mounting hole 14a is formed in the rear housing member 14, and a bearing body 15 is fixed to the rear housing member 14 by bolts in a state of being fitted to the mounting hole 14a. A pair of screw rotors (screw gears) 16 serving as fluid transfer bodies are accommodated within the rotor housing member 12. A pump chamber 17 is defined between outer peripheral surfaces of the screw rotors 16 and an inner peripheral surface of the rotor housing member 12. The specific structure of the...

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Abstract

A screw pump is provided with a pair of screw rotors serving as fluid transfer bodies. With respect to a rotation angle (x) around an axis of each of the screw rotors, a change of a lead angle (θ) from a winding start angle (0), which is the rotation angle (x) corresponding to a leading end of a spiral groove, to a winding end angle (E), which is the rotation angle (x) corresponding to a trailing end of the spiral groove, can be expressed by a lead angle change function θ(x). The lead angle change function θ(x) is structured by a combination of a plurality of change functions θ1(x) and θ2(x) having different manners of changing. It is possible to arbitrarily set a manner in which the lead angle (θ) changes in accordance with a combination of a plurality of change functions θ1(x) and θ2(x). Therefore, it is possible to arbitrarily set a fluid compression characteristic of the pump in a relation with an axial length (L) of the screw rotor.

Description

TECHNICAL FIELD[0001]The present invention relates to a screw pump, for example, used in a semiconductor manufacturing process and a screw gear suitable for the use in a screw pump.BACKGROUND ART[0002]In general, in a semiconductor manufacturing process, a screw pump is used as a vacuum pump for generating a vacuum environment. In other words, in the semiconductor manufacturing process, in order to apply various processes to a wafer under a vacuum environment, a clean vacuum environment is generated within a container by supplying an inert gas such as F2 gas or the like, which is a fluid, into a container in which the wafer is accommodated, and the gas is sucked together with an impurity (O2, CO2 or the like) remaining within the container by a vacuum pump. As such a vacuum pump, there has been conventionally known a screw pump, for example, described in Patent Document 1.[0003]The screw pump described in the Patent Document 1 is configured such that a pair of screw gears spirally m...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): F04C18/16F04C29/00F04C18/08F04C25/02
CPCF04C18/084Y10T74/1987F04C18/16
Inventor YAMAMOTO, SHINYAKURAMOTO, SATORUKOSHIZAKA, RYOSUKEITO, HIDEYUKI
Owner TOYOTA IND CORP