JPS62129588A - Pump - Google Patents

Abstract

PURPOSE:To reduce a fluid leakage at the side of a rotor and improve pump efficiency by forming uneven faces on the side of the rotor in a pump using a rotary valve. CONSTITUTION:An indefinite number of independent uneven faces 1b and 2b is formed on the sides of the gears 1 and 2 of a gear pump employing a rotary valve, as opposite to an outer casing 3. Said uneven faces 1b and 2b are formed by wire cut electric discharge machining or shot blasting, and able to prevent a fluid leakage due to labyrinth effect, thereby improving pump efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to improvements in pumps using rotating valves, particularly rotors.

[Prior art and problems]

In a gear pump, gears of the same type are meshed and rotated in an outer case, so that fluid flows between the teeth on the suction side, is sent around the outside, and is forced out of the teeth at the end of meshing. The meshing of the teeth not only pushes out the fluid, but also serves as a partition between the discharge side and the suction side. Therefore, the meshing tightness of the teeth affects the pump efficiency, but the side clearance of the gear rotor also has a significant effect on the pump efficiency. The discharge amount decreases due to leakage from the gap.

The side surfaces of conventional rotors are formed into fine smooth parts.
Attempts have been made to reduce the amount of leakage mainly by adjusting the gap, but reducing the gap increases the amount of wear and affects the service life.

[Means for solving problems]

The present invention has been proposed in view of the above points, and is characterized by forming an uneven surface on the side surface of the rotor, thereby increasing frictional resistance.

〔Example〕

The present invention will be explained below with reference to an embodiment of the drawings.

FIG. 1 shows an embodiment of a gear pump, in which gears 1.2 of the same shape are meshed and rotate in an outer box 3. The fluid flows between the teeth 1 on the suction side 3a.
It flows into teeth 1a and 2a, is sent to the outside, and is pushed out from teeth 1a and 2a during meshing. @1a and 2a are made with high precision so that they come into close contact with each other when meshing to improve airtightness and enhance fluid extrusion and partitioning actions.

FIG. 2 shows a side view of the gears 1 and 2, with an uneven surface 1b having countless independent unevenness formed on the surface facing the outer box 3;
2b is formed. The uneven surfaces 1b and 2b can be formed by electric discharge machining or wire cut electric discharge machining under controlled machining conditions, or by shot blasting in which sand grains are collided with each other, or by other methods. With these processes, it is easy to obtain a H/D of about 1/30 (1"
; Height of uneven hole, D; Diameter of hole). Further, these uneven holes are each formed independently. Incidentally, it is preferable to form such unevenness on the opposing surface of the outer box 3 as well.

Since the gear 1.2 rotates, it requires a certain gap with the outer case wall, through which the fluid leaks.

However, the above-mentioned uneven surface 1b is formed on the side surface of the rotor.
, 2b, it is possible to increase the ram resistance to the fluid passing through this gap, and it is possible to prevent fluid leakage. Therefore, the pump discharge amount can be increased. Furthermore, since the gap between the rotor can be widened, wear due to eta with the wall surface can be prevented, and the life span can be improved.

For example, when used in a gas pump, H
/D=30, the pump of the present invention has an uneven surface of 10μRmax and a gap of 20μ, and the rotor surface has a roughness of 1μR.
When a comparison test was conducted with a conventional pump formed with a smooth surface on the max, the pump of the present invention exhibited a pressure difference of about 10 T'orr in suction pressure and a flow rate of about 16 T'orr at a rotation speed of 180 ORPM.
00 rn 3/l-1, conventional pump 1200m3
/H.

In addition, the wear characteristics are that during 2000 hours of operation, the degree of vacuum decreases due to shaft wear, so the conventional pump initially pumps 1200 + n 1 / H at a pumping speed of 880 m/H.
It declined to . In contrast, the method of the present invention starts at 160
0113/H became 1200m 3 /H. In addition, in the present invention, when the side clearance at the center part of the rotor is improved to 5μ and that at the peripheral part to 12μ, a uniform 1
The lifespan was approximately doubled compared to the one formed with a 0μ gap.

〔Effect of the invention〕

As described above, since the present invention has an uneven surface formed on the side surface of the rotor, leakage from the side surface gap can be prevented, the flow rate can be increased, and the pump efficiency can be improved. In addition, by widening the side clearance, wear can be reduced and service life can be improved. It is particularly effective in gas pumps without reducing the degree of vacuum.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of the pump of the present invention, and FIG. 2 is a side view of a part of the pump. 1.2...Gear 3...Outer box la, 2a...Tooth lb, 211... Uneven surface 3a...
...Suction port 3b...Discharge port Patent application Person Inoue Japax Laboratory Representative Kiyoshi Inoue 11 ShoZ 2/-

Claims (1)

[Claims] A pump using a rotary valve, characterized in that an uneven surface is formed on the side surface of the rotor.