JPS5874887A - Vane pump - Google Patents

Abstract

PURPOSE:To prevent the generation of vortices at the region where two oil flows are joined together, by connecting an oil suction passage to an oil suction chamber in the manner that the streamlines of suction oil are tangential to the streamlines of oil circulated in the suction chamber. CONSTITUTION:An oil suction port 2a is connected to a suction passage 3a at an obtuse angle in the direction of a suction chamber 5, and the suction passage 3a is connected tangentially to the annular suction chamber 5. With such an arrangement, oil drawn from the suction port 2a joins smoothly with oil recirculated from a flow control valve 11 and the joined oil flow is straightened while passing through a relatively long suction passage 3a, so that generation of turbulences can be prevented. Further, since the flow-straightened oil joins with oil circulated in the suction chamber tangentially to the streamlines of oil flow in the chamber 5, it is enabled to prevent generation of vortices at the flow joining region and to prevent occurrence of cavitation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vane pump used in an L power steering drive device or the like.

As a conventional vane pump, there is one shown in FIG. 1, for example. To explain this, l refers to a nozzle having a suction port for oil, which is a working fluid, and a suction passage 3 following the suction port. A cam ring is positioned and installed inside the housing, and forms a suction chamber 5 between the cam ring and the inner circumference of the circular notch of the housing. Also,
A rotor 7 rotatably driven by a shaft 6 is accommodated in the elliptical notch of the cam ring. This rotor t
has slots (1) extending radially on the outer peripheral surface.

A vane 10 that protrudes and retracts in contact with and follows the notch surface of the cam ring bow, that is, the cam surface, is fitted into this slot K, and a working chamber for working fluid C is formed between adjacent vanes 10.

In the vane pump having such a configuration, oil, which is a working fluid, is introduced from a reservoir tank (not shown) into the suction chamber j through the suction port 3 and the suction passage 3. The oil introduced into the suction base j moves in the rotational direction of the low-tough, that is, counterclockwise, and is taken into each working chamber in the cam ring base from the suction port t. The oil in the working chamber V is pressurized by the change in volume of the working chamber D of each vane pump as the rotor rotates, and is discharged from a discharge port not shown in FIG.

The discharged oil is distributed between the discharge port and the discharge port (not shown).CI-k, p<p
.

A portion is returned to the suction passage 3 via the pump//f.

In this way, the trap is configured to guide oil at a constant discharge pressure to the discharge port.

By the way, in the vane pump that operates as described above, the oil is sucked in from the suction port, and the oil is returned from the flow control pallet.

They merge at the suction passage J at a substantially right angle, and then merge with the oil moving counterclockwise within the suction chamber J.

However, at this time, the oil inhaled from the suction port λ and the %
70-Control Valve//The same goes for the case where the returned oil joins in the suction passage 3, but the streamlines of the oil flowing counterclockwise and the streamlines of the oil supplied from the suction passage 3 are the same. are substantially perpendicular to each other. That is, the oil from the suction passage 3 joins the oil in the suction chamber S in a direction perpendicular to it. As a result, the suction passage 3p
Near the bend/J where the oil streamlines are deflected,
As shown in FIG. 2, a vortex 13t of oil is generated, and bubbles are generated there.

When these air bubbles mix with the oil and are sucked into the working chamber from the suction port t, during pressurization by the vane in this work step (c), these air bubbles are crushed, giving an equilibrium to the oil and discharging it. There have been problems such as pulsating the oil pressure output from the outlet and generating abnormal noise, causing a so-called cavitary phenomenon and making the assisting operation of the power steering unstable.

The present invention is designed to improve the problems in the conventional vane pumps, and the present invention is designed to improve the problems in the conventional vane pump. On the other hand, by facing the suction passage,
The purpose of the present invention is to provide a vane pump that prevents the generation of vortices at a portion where the streamlines of both oils meet.

Embodiments of the present invention will be described below based on the drawings.

FIG. 8 shows a vane pump according to the present invention, in which the same parts as shown in FIG. 1 are given the same reference numerals. In FIG. 8, λa is an oil suction port, and this suction port a is a relatively long suction passage to the suction chamber j. It intersects alC at an obtuse angle in the suction chamber j direction. Further, the suction passage Ja4d intersects the annular suction chamber 5 in a tangential direction.

According to this configuration, the oil sucked from the suction port core a gently merges with the streamlines of the flowing oil, and the merged oil flows into the long suction passage 3a. turbulence is prevented by receiving a rectifying effect. The rectified oil gently merges in the tangential direction to the :& line of the oil circulating in the suction chamber j, and the generation of vortices at the merged portion can be completely prevented. In this way, the generation of air bubbles is eliminated, and the cavitation phenomenon of pulsating pressure and abnormal noise of the pump due to the collapse of air bubbles can be completely prevented.

On the other hand, the center of the suction gj and the rotation center of the rotor 70 are
They are provided with a slight offset, so that the cross-sectional area of the suction chamber j is formed so as to gradually become smaller from the suction port t on the upstream side toward the suction port on the downstream side.

By doing this, a part of the oil introduced into the suction chamber S from the suction passage Ja is sucked into the working chamber D from the upstream suction port t.

The oil pressure in the suction chamber j near the suction port on the downstream side decreases, and the oil pressure sent from that suction port to the other working chamber t is prevented from decreasing, thereby completely preventing the occurrence of cavitation in that part. . In this way, oil is discharged from the two working chambers 2 at high discharge pressures, and a balanced and stable assisting force for power steering and other load control pressures can be obtained.

The occurrence of cavitation due to the discharge pressure difference between the two working chambers can also be effectively prevented.

As explained above, according to the present invention, the flow line of oil sucked from the outside through the suction passage is tangential to the flow line of oil flowing through the annular suction chamber leading to the suction port of the pump body. The suction passage and the suction chamber are made to communicate with each other so as to intersect with each other in the directions, so that when the two streamlines of oil merge, no vortex is created, which in turn prevents the pulsation of the working oil pressure due to cavitation. Fluctuations and abnormal noises can be reliably prevented. In this way, there is an advantage that the power steering control 2'Σ due to the operating oil pressure can be stabilized.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional vane pump, Fig. 312 is an explanatory view showing the state of cicada flow generation in its main parts, and Fig. '8 is a cross-sectional view of the vane pump of the present invention. 3.3a...Suction passage, 5...Suction chamber, I...Suction port.

Claims (1)

[Claims] The working flow drawn from the outside through the suction passage, the flow line of the body, passes through the suction port of the pump.
A vane pump in which the suction passage and the suction chamber are connected to each other so that the flow lines of the flowing working fluid are in the same direction and intersect in a substantially tangential direction.