JPH0436272B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a vane pump that sucks in and discharges liquid such as oil.

<Prior art> A rotor that rotates inside a cam ring is provided with vane chambers radially, and has vanes that slide in the radial direction within the vane chamber.As the rotor rotates, the volume of each pump chamber divided between the vanes increases. Increase or decrease;
Vane pumps that suck in liquid through a suction port and discharge it through a discharge port are well known.

By the way, in the suction section and the discharge section,
The vane was pushed in the backward direction by the hydraulic pressure acting on the vane, creating a gap at the tip of the vane that slidably contacts the cam ring, causing a problem in which fluid inside the pump chamber leaked.

In order to solve this problem, a back pressure groove that guides a part of the discharge pressure to the vane chamber at the back of the vane is provided in the suction and discharge sections, and the back pressure groove on the discharge section side, where the pressure is higher than the suction side, is For example, a vane pump that is equipped with a throttle hole to increase pressure, applies back pressure to the liquid discharged from the vane chamber when the vane retreats, and forces the tip of the vane against the cam ring to ensure a sealing function is disclosed in U.S. Patent No. 3207077. provided in the issue.

<Problems to be Solved by the Invention> In the case of the conventional vane pump described above, the number of vane chambers communicating with one discharge side back pressure groove varies from 2 to 3, and the combined discharge amount also varies as shown in the lower graph of Fig. 4. It fluctuates. In a region 20 where the amount of oil pushed out by the rear end of the vane into the back pressure groove decreases due to this fluctuation, the tip of the vane separates from the cam ring, causing a problem of pulsation or vibration.

The present invention provides a vane pump that solves the above-mentioned conventional problems by preventing insufficient pressure rise even when the amount of oil pushed out by the vanes decreases.

<Means for Solving the Problems> The present invention divides the back pressure groove in the discharge section having a throttle hole into a plurality of parts, and provides a back pressure groove located between the divisions to correspond to an area where the amount of oil discharged from the vane chamber decreases. A sealed section of the vane chamber is formed by

<Function> The above-mentioned present invention provides a vane chamber sealed section even in a region where the amount of oil pushed out by the vane decreases, so the pressure inside the vane chamber increases, and the vane tip is reliably pressed against the cam ring to maintain the sealing function. .

<Examples> Examples of the present invention will be described below based on the drawings. In FIGS. 1 and 2, reference numeral 1 denotes a pump housing, the opening at one end of which is closed by an end cover 2. As shown in FIG. A cam ring 3 is fixedly installed inside the pump housing 1, and a rotor 5 rotated by a rotating shaft 4 is installed inside the cam ring 3.
is provided. This rotor 5 is provided with vane chambers 6 radially, into which vanes 7 are fitted so as to be slidable in the radial direction.

A side plate 8 is provided on the side surface of the cam ring 3 and the rotor 5 on the rotating shaft 4 side, and an end cover 2 is provided.
A pressure plate 9 is arranged on the side surface,
The pressure plate 9 is connected to the cam ring 3 by a spring 10 interposed between the pressure plate 9 and the inner surface of the end cover 2.
It is also pressed toward the rotor 5 side. A hollow chamber 14 is formed between the pressure plate 9 and the end cover 2.

Further, an annular groove 11 serving as a suction passage is formed between the outer periphery of the cam ring 3 and the pump housing 1, and is defined between the annular groove 11 and the vane 7 in the side plate 8 and the pressure plate 9. A suction port 12 communicating with the pump chamber is provided.

Further, the side plate 8 is provided with a discharge port 13a that communicates between the pump chamber and the flow rate control valve 18, and the pressure plate 9 is provided with a discharge port 13b that communicates between the pump chamber and the hollow chamber 14.

Further, the pressure plate 9 has a back pressure groove 15 on the suction side in which the vane chamber 6 of the retreated portion of the vane 7 and the hollow chamber 14 communicate with each other in the suction section, and a back pressure groove 15 in which the vane chamber 6 and the hollow chamber 14 communicate with each other in the discharge section. A back pressure groove 17 on the discharge side is provided which communicates with the back pressure groove 17 on the discharge side.
7 has an aperture hole 16.

In the present invention, the back pressure groove 17 on the discharge side is divided into a plurality of sections in the discharge section, as is clear from the developed view of FIG. A sealed section 19 of the vane chamber 6 is formed between the divisions of the back pressure groove 17. Note that 21 in FIG. 4 indicates the cam lift of the cam ring 3.

Since the present invention has the structure as described above, the liquid pressure discharged from the discharge port 13b into the hollow chamber 14 is as follows.
It is guided into the vane chamber 6 from the back pressure grooves 15 and 17, and exerts a back pressure action that presses the vane 7 against the cam ring 3. Especially on the discharge side where the pressure inside the pump chamber increases.
A back pressure higher than the back pressure on the suction side is applied by the throttle hole 16 to ensure a seal.

By the way, in the conventional back pressure groove that is continuous over the entire discharge section, the amount of oil pushed into the back pressure groove decreases due to the retreat of the vane 7 by the cam lift 21.
Although the back pressure to press the vane 7 is insufficient, in the present invention, the amount of oil remaining in the sealed section 19 of the vane chamber is compressed between the divisions of the back pressure groove 17 to increase the back pressure.
This ensures the pressing force of the vane 7. By setting the interval between the sealed sections 19 to be large or small, the pressure increase can be adjusted in size.

<Effects of the Invention> As described above, according to the present invention, the back pressure groove in the discharge section where the amount of oil pushed out by the vane is small is eliminated, and a vane chamber sealed section is formed. Due to the increase in the pressure of the oil amount, sufficient back pressure is ensured to press the vane, which maintains a pressure seal with the cam ring and has the effect of preventing pulsation and vibration.

[Brief explanation of drawings]

Figure 1 is a sectional view of the present invention, Figure 2 is Figure 1-
3 is a cross-sectional view taken along a line taken from FIG. 1, and FIG. 4 is a developed view of main parts for explaining the operation of the present invention. 1...Pump housing, 3...Cam ring, 4...
Rotating shaft, 5... Rotor, 6... Vane chamber, 7... Vane, 12... Suction port, 13a, 13b... Discharge port, 14... Hollow chamber, 15, 17... Back pressure groove, 16
...Aperture hole, 19...Sealed section.

Claims (1)

[Claims] 1 It has a cam ring, a rotor that rotates inside the cam ring, and vanes that slide in the radial direction within vane chambers provided radially on the rotor, and as the rotor rotates, the volume of each pump chamber divided between the vanes increases. A back pressure groove is provided in the suction and discharge sections to conduct a part of the discharge pressure to the vane chamber at the back of the vane in order to increase and decrease the pressure and seal the vane in the cam ring direction. A vane pump having a hole, characterized in that the back pressure groove of the discharge section is divided into a plurality of sections, and a vane chamber sealed section is formed between the divisions.