Gear Pump with Different Teeth 1

Inventor: Varuzhan Harutyunyan, Nor-Nork 9th massive 97/7, 0059 Yerevan, Armenia

Application No.: AM20120048U

Filed: March 19, 2012

Field of the invention

The invention concerns positive displacement rotary pumps.

Description of related art

An external gear pump in the field concerned is described in the book: A. G. Skhirtladze, V. I. Ivanov, V. N. Kareev “Gidravlicheskie i pnevmaticheskie sistemi” pages 94-101, published at 2006.

Abstract

The utility model represents as rotary pump.

Gear Pump with Different Teeth consists of a case, a pair of meshing cylindrical gears in it, two ports in the case: one for the liquid suction and the other one for the liquid discharge. One of the gears rotates from actuator. The teeth of the gears have the same pitch diameter.

Each gear has two opposite big teeth and two opposite big cavities having the pitch greater than pitch of small teeth in 3, 5, 7 or more times. The addendum diameter of big teeth is greater than the addendum diameter of small teeth, whereas the dedendum diameter of big cavities is taken so, that big teeth can easily mesh with them.

The reliability and effectiveness are enhanced.

Brief Description of the Drawings

Fig. 1 is an axonometric view of the gear pump with different teeth without cover

Fig. 2 is a plan view of the pump without cover

Description

Engineering level

The external gear pump consists of meshing gears and the case, which has two ports: one for liquid intake and the other one for its discharge. One of the gears receives rolling motion from actuator, while the other one rotates through meshing with the previous gear. The liquid is filled into the cavities between teeth and is delivered to discharge port along the case contour. The liquid cannot flow in the opposite direction because of the teeth strong meshing.

The pump has following limitations:

Since the suction occurs when a tooth of one gear leaves a cavity of the other gear, the pump generates low vacuum, which prevents its use for delivering high viscous liquids and limits suction head as well. Based on the suction and discharge nature, the pump has low admission and compression ratio, which results high volumetric losses after slight wear of teeth especially at high pressure.

Disclosure of the utility model

The purpose of the invention is to improve the gear pump design so, that it will have relatively high admission and compression ratio to enhance its volumetric efficiency.

The pump has gears 1 and 2, which are in pin connection with case 3 through shafts 4 and 5. The case has inlet 6 and outlet 7 ports. The gears have many small teeth 8, two opposite big teeth 9 and two opposite big cavities 10. The pitch of big teeth and big cavities is greater than the pitch of small teeth in 3, 5, 7 or more times. The contours of all teeth and big cavities have the same pitch diameter 11. The gears are mounted against each other in the case in such a way that a big tooth of one gear meshes with a big cavity of the other gear.

The pump operates in the following way:

The actuator 12 rotates gear 1 through shaft 4. The second gear 2 is rotated from gear 1 through meshing. When the pump rotates in the mentioned direction of Fig. 2, the liquid is filled through inlet port 6 into continuously increasing chamber between two big teeth of different gears till another big tooth gets in touch with case flank in the suction zone. Afterwards the liquid in the chamber between two big teeth of the same gear travels in constant quantity till the next big tooth gets free of touch with case flank. Then the liquid is discharged through outlet port 7, because the volume of the liquid bounding chamber continuously decreases. The gear meshing eliminates the liquid opposite flow from discharge zone to suction zone.

Because of the high volume of the chamber between two opposite big teeth, the pump has high admission and compression ratio, which reduces volumetric losses, provides high suction head and enables to deliver high viscous liquids.

Since the gears have a lot of small teeth (rated), more teeth are engaged in meshing, which improves meshing hermeticity and volumetric efficiency accordingly.

The pump can be used in hydraulic machines as pump and hydraulic motor and can deliver lubricants, liquid fuel and other liquids as well.

Claim