JPS58170868A - Vane type pump - Google Patents

Abstract

PURPOSE:To enable to reduce the pulsation of the discharge pressure of a vane pump, by constituting the portion of the inner surface of a cam ring substantially overlapped with a discharge opening by use of an Archimedes curve, and thereby rendering the vane lift speed constant during the discharge stroke of the pump. CONSTITUTION:The inner configuration 1' of a cam ring 1 is constituted by use of an Archimedes' curve. That is, most of the portions of the inner surface of the cam ring 1 overlapped with a suction port 5 and a discharge port 5 are constituted by use of an Archimedes' curve, and small areas at the opposite ends of said portions are connected smoothly to remaining arcuate portions. Further, vanes 3a, 3b are extended through the inside of a rotor in diametrical directions, and the opposite ends of these vanes 3a, 3b are always held in sliding contact with the inner surface of the cam ring 1, so that change of the acceleration speed can be rendered negligible. Therefore, it is enabled to reduce pulsation of the discharge pressure.

Description

[Detailed description of the invention] The present invention relates to a vane type pump.

Vane reservoir hydraulic pumps used in automobile power steering* are required to minimize zero variation in discharge flow rate. For this reason, in a conventional vane type hydraulic pump, the inner surface of the cam during the discharge stroke is formed into a cycloidal curve or a higher-order curve, which smoothly connects to the arcuate curves before and after the cycloidal curve. That is, Fig. 1 shows a pressure-balanced vane type pump, and Fig. 2 shows a pressure non-balanced vane type pump with both transverse openings.
is the rotor, and 3 is slidable in the diametrical direction of the rotor 2!
I hold the vane, 4 is the suction port, 5 is the discharge port (To),
At any rotational position of If-2, the support 73 comes into sliding contact with the cam inner surface 1' of the cam ring 1. The action of the pump is
A suction stroke in which the bay 73 passes through the suction port 4, a confinement stroke in which the valve 73 passes through the discharge port 5, and a confinement stroke is formed between the terminal end of the suction port 4 and the beginning end of the discharge port 5. The inner surface of the cam ring during the closing stroke has a slight precompression effect based on the circular arc between the rotor 20 rotational axis and the inner center, or based on this circular arc. The volume change of the working chamber in this case is constant. However, in the working chamber in front of the rotation, there is a vane (the first
The discharge rate will be affected by the change in the volume of the lift portion (indicated by 3a in FIG. 3 and FIG. 2). The pump discharge amount Q [#'/S) of the configuration shown in the figure is, however, the arc radius [scale] rr + of the RTtIll insertion stroke.
a-Evening radius [-] Rc: Radius of the cam curve in the discharge stroke [bait] ω; Angular velocity of the vane (rad/s) B: Thickness of the vane W: Axial length of the cam and vane [simplified] So, dR
All except c/dt can be expressed as constants, but d R(,'d
t represents the force, that is, the rate of change in lift of the vane 3. If RC is a kniferoid curve or a higher-order curve as described above, its value changes depending on the phase of the vane 31, and as a result, the pump The pump flow rate Q when one vane 3m of the vane type hydraulic pump having the configuration shown in FIG. The angle ψ of passing through the discharge port 5 is defined as one cycle, and the cycle continues with fluctuation every time the bead 73 passes.

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a single-type pump with less variation in discharge flow rate and pressure.

Examples of the present invention will be described in detail below.

FIG. 5 shows a sectional view of one embodiment of the vane type pump according to the present invention, and the same parts are designated with the same symbols. 1 is a cam ring, and its inner surface shape 1' is formed based on an Archimedean curve according to the present invention.

That is, most of the parts that overlap the inlet 4 and the outlet 5 are formed along an Archimedean curve, and a high-order transition curve in which small ranges at both ends of the part are smoothly connected to other arcuate parts. formed along the On the other hand, vane 3#'
i Extending through the rotor 2 in the diametrical direction, one vane 3
Both ends of a and 3b are formed so that they are always in sliding contact with the opposing inner surfaces of the cam ring l. In the area where the vane 3a intersects with another vane 3b, the blades 73.3m and 3b are appropriately formed so as not to interfere with each other. The intake port 4 and the discharge port 5 are side plates (not shown) that close the sides of the cam ring 1.
K is installed.

Here, an example of a curve forming the cam inner surface 1' of the cam ring 1 will be explained. In addition, each symbol is the same as that used in the above-mentioned formula (1), but - is w with the terminal end of the discharge port 5 as the base point, and in Fig. 5, the angle [ad] in the clockwise direction is indicated, and R is The length from the center of the rotor 2 to the inner surface of the cam of the cam ring 1 is [■]. h and k are numbers appropriately selected to obtain a continuous curve. Also, ψ/2 is The angle range of the transition curve is as shown in FIG.

(a) Small circular arc part (O<0≦π/2) Rヰ'r
(2) (b) Suction stroke (π
/2〈-≦K) (b-1) Transition curve: cycloid curve half period θ′ l Re= r, 10h(j −] sin (2fθrif)
) (3) (However, θ'=e-π/2) (b-2) Main curve: Archimedean curve R=rr1h
/20 wards・#' (4) (However, F, = I-
π/2−ψ/2) (b −3) Transition curve! Kniferoid curve half period Re
r, +x・(π/2-9)+h (17?-B stn (2xθytp>>
(5) (However, Q'-m-π+ψ) (C) Confinement magistrate s! (π〈θ≦3π/2)1−R
r (6) (d) Dischargeability I! (3π/2〈θ≦2π) (d-1) Transition 1ikl
l: kniferoid curve semi-waste period 11 = Rr-k(#'
/? - Yusin (2r#'/9')) (7) K (however, #=#-3x/2) (d-2) Main 1lklIX Archimedean curve 1wBr
-1m12- K-11' (8) (However, #'=$-3π/2-ψ/2)Cd-3) m1 row ill:? Ikroid curve half period R-Br-K (π/2
−ψ)−1.

h(#7ψ-stn (2r#2F)) (9
)2π (However, #=#-2π+ψ) In the above formulas, R(θ) + R (θ + K) = constant (10), so one bee 73m, 3b is passed through the rotor 2. This enables a structure in which both ends thereof are always in sliding contact with two opposing positions on the inner surface 1' of the cam.

Figure 6 is an R diagram based on the above formulas for the vane type pump with the configuration shown in Figure 5, where k and h are table values so that both ends of the transition curve have a circular arc and a tangent line that is the same as the slope of the Archimedean curve, respectively. It becomes. Further, a true curve representing the lift speed of the vane and a curve representing the lift acceleration of the vane are also shown at the same time, and in these curves as well, the transition curve and other curves of instantaneous contact are smoothly continuous.

The zero operation of the vane type pump having the above configuration will be explained.

When the rotor 2 is rotated clockwise in the direction P in FIG. C, which causes oil to flow into the working chamber from the suction port 4;
This is closed in the confinement stroke and carried to the discharge stroke with a constant volume of 0. Since the volume of the working chamber is reduced, the oil is discharged from the discharge port 5 while being pressurized.

In this embodiment, the rate of change in lift during the discharge stroke of the pump 73 is constant as shown in the blood contraction diagram in FIG. q
becomes constant. Although dRe/dt is not constant in the transition curve, since it occupies a small proportion of the entire discharge stroke, the overall fluctuation in the discharge flow rate is small and the discharge pressure is fairly stable.

On the other hand, as can be seen from the R diagram, the lift acceleration of the vane shows a sudden change at K, but in the vane type pump with the configuration shown in Fig. It penetrates through the cam, and both ends always follow the inner surface shape of the cam and slide into contact, so the change in acceleration is almost Ml! You can prevent this from happening.

Furthermore, although in the above embodiments the Fi confinement stroke has an arcuate shape, the present invention can also adopt a cam inner surface shape that has a pre-compression effect. For this purpose, the number of per allowance μ
Using an Archimedes curve that changes from m to 10-odd μm,
The Archimedean curve of the discharge stroke or suction stroke can be connected by a transition curve to a quintic curve that satisfies the following conditions.

However, α, β: Angle of the connection position, R,, R,: Radius of the transition curve Kl p Kl ” The slope of the Archimedean curve connected to both ends of the transition curve.

As described above, according to the present invention, the vane lift speed during the discharge stroke, which is the cause of fluctuations in the discharge flow rate, is kept constant, thereby reducing discharge pressure pulsations caused by fluctuations in the discharge flow rate. In addition, if the cam ring inner surface shape is formed rotationally symmetrically, the vane can pass through the rotor and both ends of the vane can slide against the cam ring inner surface at the same time, allowing the vane drift acceleration to better follow the cam ring inner surface shape. A vane type pump with excellent operation can be obtained.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views of commonly used vane-type pumps, FIGS. 3 and 4 are cross-sectional views and graphs for explaining discharge flow rate fluctuations of conventional vane-type pumps, and FIG.
The figure is a cross-sectional view of an embodiment of a vane type pump to which the present invention is applied, and Figure 6 is an R diagram of the vane type pump shown in Figure 5.
Please refer to figure J and line diagram. 1...Cam ring, 2...Rotor, 3...Vane, 4...Intake port, 5...Discharge port Patent Applicant Co., Ltd. Japan Auto Parts Research Institute Patent Application Agent Blue Akira Yamaguchi Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In a vane-type pump in which the tip of a vane supported by a rotatable rotor so as to be movable in the OX radial direction KWI slides on the inner surface of a cam of a cam ring surrounding these vanes, the inner surface of the cam almost overlaps with the discharge port. A double vane type pump that is formed based on the Archimedean curve in its parts and configured so that the vane lift speed during the discharge stroke is constant.