DE2157770A1 - Rotary vane pump - Google Patents

Description

Sperry Rand Corporation
Troy, Michigan 48084, USA

The invention relates to a rotary vane pump with a Arrangement of connecting passages and a Noekenring, as well as a device for changing the Angular position of both to each other.

The rotary vane pump is a powerful, compact, reliable and low-wear device, which is widely used in hydraulic power plants and for other pumping purposes; similar arrangements are also used as hydraulic rotary motors. For such facilities one usually uses a cam ring with a non-circular contour relative to the rotor axis, and therefore that is Advancing the slide determined by the contour of the cam ring. Such facilities have been proposed with the possibility of changing the displacement by means of an arrangement for setting the phase relationship between the cam ring and the device switching passages. This was so far inexpedient, since switching passages working sensibly with full displacement at medium displacement settings with regard to the enclosed fluid result in an increase in serious problems. The destructive

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The effect of fluid containment can only be through use can be prevented by switching passages, which result in a serious loss of performance when setting full of repression with them ..

It is an object of the present invention to provide an improved rotary vane pump or motor to create in which the displacement by shifting the angle between the cam ring and the Switching passages can be changed and which on the one hand the destructive effect of the in the working group avoids entrapped fluid and on the other hand the use of sensible working Changeover diffusers made possible.

According to the invention, this object is achieved in that the cam ring has an internal structure along it of which the inlet area of the cam ring increases in two stages and the outlet area decreases in two stages.

The invention is explained in more detail below using an exemplary embodiment. In the accompanying drawing demonstrate?

Fig. 1 is a longitudinal section through a pump housing which is a preferred inventive Embodiment representsj

Figure 2 is a sectional view at 2-2 in Figure 1;

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Figure 3 is a schematic view of the basic elements of the pump with the parts in a cam ring setting are shown for a medium displacement;

4 shows a view corresponding to FIG. 3, with the parts in a setting for maximum Displacement are shown;

5 shows a view corresponding to FIG. 3, with the parts in a setting for minimal Displacement are shown;

Figure 6 is a cam construction diagram for a typical cam ring;

FIG. 7 shows a pump displacement diagram corresponding to the cam construction diagram shown in FIG. 6.

In the exemplary embodiment selected to explain the present invention, a rotary pump, which is suitable for pumping fuel into an aircraft, constructed as a unit which is in a stationary housing with inlet and outlet feeds to the Feeding and discharging the fuel to the pump and away from it can be installed, with such a housing does not form part of the present invention.

The unit has 5 main parts, a base plate 10, a first wall panel 12, a spacer ring 14, a second wall panel 16 and a head end 18. These parts are held together by a series of bolts 20

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(Fig. 2). In the wall panels 12 and 16 are inlet openings 22 (FIG. 3) and in the base plate 10 and the head end 18 outlet openings 24 are provided to over the circumference arranged passages 26 with passage openings 28 (Fig. 3) in the wall panels 12 and 16 in connection rise.

In sleeve bearings 30 is a shaft 32 with a drive head 34 mounted at its right end, with which a rotor 36 is serrated at 38. The VS-Ie 32 can have suitable Passages indicated generally at 35 for the circulation of pumped fluid for lubrication and Have cooling of the bearings 30. As shown in Fig. 2, the rotor 36 carries a plurality, in the present case Case eleven, slides 39 which can be displaced radially in their respective slots. Freely movable on the circumference of the rotor 36 is a cam ring 40 with an inner contour egg-shaped Structure, which will be described in detail later. On the outside, the cam ring 40 has a large number of recesses 42, which are arranged at a distance of 90 ° between webs 44 which are in contact with the four circular Surfaces 46 on the inside of the spacer ring 14 can oscillate. Between the surfaces 46 is a Plurality of abutments 48 provided, each of which carries a radially displaceable slide 50, which with the corresponding circular surface 42 of the cam ring 40 is engaged and transmitted by hydraulic pressure. ,, which is transmitted via corresponding passages, not shown is, is pushed against,

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Figures 3 »4 and 5 schematically represent the middle, maximum and minimum displacement setting of the cam ring relative to the switching passages represent » In these figures the contour of the cam ring is shown only in a fairly general manner, which by graphical representations of the cam lobe and the pump displacement, as shown in FIGS. 6 and 7 are shown, can be explained in more detail. To avoid fluid entrapment at medium and Minimizing the lower displacement maintains the rise and fall of the cam contour a special shape. From Figure 6 it can be seen that both the cam rise along the inlet face as well as the cam drop along the outlet surface " goes on in two stages. However, these are not symmetrical with respect to inlet and outlet. The first The inlet contour stage is from the first stage Outlet contour different, namely what concerns the arc extension and the total stroke, as well as the amount of rise or fall. Likewise, the overall rise occurs along the inlet contour after one shorter arch path than that for total waste along the outlet contour is required.

Such typical contours lead to displacement curves as shown in FIG. 7, which the displacement rates along the inlet and the

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Show outlet contours and also the theoretically resulting Displacement of the entire pump at different positions of the adjustable cam ring 40. One can from this see that there is a large difference between the shape of the curves for inlet and outlet. this results in a considerable reduction in the amount of that entrapped between the inlet and outlet ports Fluidum, while the shape of an individual intermediate slide space changes, although the arc width of the web between each inlet and outlet port is such that a direct bypass path at each rotor position is avoided.

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Claims (6)

Claims \ 1./ Rotary vane pump, with an arrangement of connecting passages and a cam ring, as well as a device for changing the angular position of the two to one another, characterized in that the cam ring has an inner contour along which the inlet surface of the cam ring in two stages increases and the outlet area decreases in two stages. 2. Pump according to claim 1, characterized in that the arc length of the first stage of the inlet face of the arc length of the first stage of the outlet surface is different. 3. Pump according to claim 1 or 2, characterized in that the total increase of the first stage inlet area from the total decrease of the first stage outlet area is different. 4. Pump according to one of claims 1 to 3, characterized in that the rate of increase of the first stage of the inlet area from the rate of decrease of the first stage of the outlet area is different. 209824/0666 5. Pump according to one of claims 1 to 4, characterized in that the total arc lengths of the inlet and outlet surfaces are different. 6. Pump according to one of claims 1 to 5 »characterized in that the cam ring is displaceable relative to the pump and a device for supplying a fluid pressure in Circumferential direction is provided to move the cam ring. 209824/0666