JPH01147177A - Internal gear rotor for pump or motor - Google Patents

Abstract

PURPOSE:To set a tip clearance between two rotors to zero and thereby improve the discharge capacity of a pump by using metal or ceramics for an inner rotor and elastically deformable resin for an outer rotor, respectively. CONSTITUTION:Two rotors 1, 2, whose tooth number difference is one each, are combined together and thereby an internal gear rotor 4, producing a pumping chamber 3 between tooth surfaces of these rotors, is constituted. The inner rotor 1 may be any mechanical works of metal as iron or the like, but a part of ferrous sintered metal is better in view of manufacturability. As for material for the outer rotor 2, acrylonitrile-butadiene-styrene (ABS) resin may be used, but an engineering plastic resistible to a temperature of more than 100 deg.C is preferable to that. With this, harmonizability in engagement is very good and, what is more, sliding resistance can be made smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an internal gear rotor with a single tooth difference suitable for use in a low hydraulic pump or a low hydraulic motor.

[Conventional technology and its problems]

It has already been considered that the internal gear rotor used in trochoidal gear pumps be made of resin to increase strength and improve processing accuracy.

However, in conventional pumps of this type, both the inner and outer rotors, which are the components of the internal gear rotor, are made of resin, so it is necessary to ensure smooth rotation, similar to the case with metal rotors. Therefore, it is necessary to provide some tip clearance between the inner and outer rotors, which makes it difficult to increase the pump's discharge efficiency, especially when using low viscosity fluids, and furthermore, it is necessary to provide some tip clearance between the inner and outer rotors, which can cause pressure leaks. In order to reduce the discharge loss by reducing the size of the rotor, there is a problem in that the machining accuracy of the rotor must be sufficiently increased.

Furthermore, when resin gears are meshed with each other, sliding wear progresses rapidly, resulting in a problem that the gears cannot withstand long-term use.

This invention aims to eliminate these problems.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention has an inner rotor made of metal or ceramic, and an outer rotor having one tooth difference with respect to the inner rotor, made of an elastically deformable resin.

[Effect]

Unlike the meshing of resin rotors, the metal or ceramic inner rotor and the resin outer rotor have good conformability, and the sliding resistance is kept low, so that the chip clearance does not change significantly.

In addition, the outer rotor can be elastically deformed, and if it interferes with the inner rotor, it will shrink in size due to deformation. Smooth rotation of the rotor is guaranteed.

Furthermore, since the tip clearance that can lead to liquid leakage can be designed to zero, the pressure can be as low as 5 kg/cm" or less.
The discharge performance of the pump can be maintained at a high rate even for low-viscosity liquids such as water and liquid fuel.

〔Example〕

An embodiment of the invention is shown in the accompanying drawings.

In the figure, 1 is an inner rotor, 2 is an outer rotor, and an internal gear rotor 4 is constructed by combining these two rotors 1.2, which have a difference in the number of teeth by one, to create a pumping chamber 3 between the tooth surfaces of both rotors. ing. 5 is a pump housing housing the internal gear rotor 4, 6 is a suction port provided in the housing, 7 is a discharge port, and 8 is a drive shaft.

The inner rotor 1 may be a machined product made of metal such as iron, but iron-based sintered metal has better manufacturability.

Although ABS resin or the like may be used as the material for the outer rotor 2, it is more desirable to use an engineering plastic that has excellent high-temperature properties and can withstand temperatures of 100° C. or more.

Polyether sulfone-based and polyether ketone-based resins are used as the engineering plastics, and the outer rotor is made of unreinforced resins and reinforced materials such as inorganic fillers, gas fibers, carbon fibers, etc. When tested using a combination of a sintered metal inner rotor with a composition of Fe-2Nf-1G and a tip clearance of zero, it was found that in a combination of resin rotors made of the same material, the sliding surface wore out by more than 0.1+me in a few hours. The gap between the interdental seals expanded and the pump performance decreased significantly, but with the combination of this invention, the sealing performance of the interdental seals is maintained and there is no problem even during long-term rotation. Ta.

In addition to the above-mentioned engineering plastics, examples of engineering plastics that can be used for the outer rotor 2 include polyimide-based, polyamide-based, polyethylene terephthalate-based, and polyphenylene sulfide-based resins.

〔effect〕

As described above, in the internal gear rotor of the present invention, the inner rotor is made of metal or ceramic, and the outer rotor is made of elastically deformable resin, so that the tip clearance between both rotors can be reduced to zero and the pump discharge can be improved. Performance can be greatly improved, and the allowable dimensional error of the rotor can be increased to facilitate processing.

Furthermore, since the sliding resistance between the rotors is reduced compared to the case where resin rotors are combined, durability is also improved.

The features of the internal gear rotor of the present invention can be fully utilized not only in pumps for low-viscosity, low-pressure liquids, but also in motors rotated by low-pressure liquids.

[Brief explanation of the drawing]

The attached drawing is a sectional view showing an example of the internal gear rotor according to the present invention assembled into a pump housing. 1... Inner rotor, 2... Outer rotor, 3... Pumping chamber, 4... Internal gear rotor, 5... Pump Housing, 6... Suction port, 7...
...Discharge port, 8...Drive shaft.

Claims (2)

[Claims] (1) The inner rotor is made of metal or ceramic,
An internal gear rotor for a pump or motor, characterized in that an outer rotor with a difference in the number of teeth of one tooth from the inner rotor is formed of an elastically deformable resin. (2) The internal gear rotor for a pump or motor according to claim (1), wherein the tip clearance between the inner rotor and the outer rotor is zero.