JPS6346708Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a vane-type pump used for evacuation, etc., and is particularly concerned with improvements to reduce noise.

[Conventional technology]

Conventional vane type pumps are shown in Figures 1, 2, and 3.
The diagram will be explained. 1 is a bracket rear, 2 is a shaft supported by the bracket rear 1 via a bearing 3 and driven by an engine 14;
is a rotor fixed to this shaft 2 by spline fitting; 5 is a housing having a cylindrical inner peripheral surface eccentric to the centers of the shaft 2 and rotor 4; 6 is a bolt for fixing this housing 5 to the bracket rear 1; , 7 are vanes inserted into vane grooves 15 arranged radially in the rotor 4 so as to be slidable in the radial direction. Reference numeral 8 denotes a gasket that keeps the joint surface between the bracket rear 1 and the housing 5 airtight; 9 an oil seal that is fixed to the bracket rear 1 and slides on the shaft 2 to keep the working chamber of the pump airtight; 10;
is an inlet provided in the housing 5,
It is connected to the vacuum tank 11. Reference numerals 12 and 13 are a discharge port and an oil supply port provided in the housing 5, and are connected to an oil pan and an oil pump of the engine 14, respectively.

Next, the operation will be explained. First, when the shaft 2 rotates in the direction of the arrow, the centrifugal force generated in the vane 7 causes the vane 7 to protrude outward, and the housing 5
The pump rotates while sliding on the inner wall of the vacuum tank 11, thereby sucking in air from the vacuum tank 11 through the suction port 10 and exhausting it through the discharge port 12, thereby performing a pumping action. On the other hand, the oil supplied into the housing 5 from the oil filler port 13 is
The sliding surfaces of the vanes 7 and the rotor 4 are lubricated, and the oil is discharged from the discharge port 12 to the oil pan.

[The problem that the idea aims to solve]

The conventional vane type pump as described above has a problem in that when the pressure inside the vacuum tank 11 becomes high vacuum, abnormal noise is generated.

FIG. 4A shows a vacuum characteristic curve of a conventional vane pump, and B shows a noise generation zone. Further, FIG. 5a shows the measured noise level when the pressure of the vacuum tank 11 was within the noise generation zone.

The causes of this noise depend on many factors, such as the dimensions of each part of the pump, the shape of the vanes, the position and shape of the inlet and outlet ports, and the amount of oil supplied. Ta.

Additionally, experimental results have proven that when the pressure inside the vacuum tank is lowered below the noise generation zone, the noise level is reduced as shown in Figure 5b. This resulted in a significant increase in costs, and also caused problems such as pressure fluctuations occurring more than necessary due to failure of the pressure limiting device.

This idea was made to eliminate these conventional problems.With an extremely simple configuration, a constant amount of gas can be introduced into the pump operating chamber at all times, and the pressure inside the vacuum tank can be increased. The aim is to obtain a vane-type pump that prevents vacuum formation and reduces noise.

[Means to solve the problem]

The vane type pump according to this invention has a notch step provided at least on the surface of the vane tip among both surfaces that correspond in the circumferential direction between the opening of the vane groove and the vane tip. .

[Effect]

In this invention, when the rotor rotates and the vanes are pushed into the vane grooves in the discharge zone, a space is formed between the notch step of the vane and the inner peripheral surface of the cylindrical part of the housing, and gas is taken in. When the vane reaches the inlet position of the housing from this position, the gas in the space is introduced into the working chamber of the pump.
The degree of vacuum in the vacuum tank prevents it from entering the noise generation zone, reducing noise.

〔Example〕

6 and 7 show an embodiment of the vane type pump according to this invention. In the figure, a notch step 7 is formed on each surface corresponding to the circumferential direction between the tip of the vane 7 and the opening of the vane groove 15 of the rotor 4.
a, 15a are provided. As a result, the rotor 4
rotates and the vane 7 is pushed into the vane groove 15 by the inner peripheral surface of the housing 5 in the exhaust zone. A space 16 is formed by the cutout step 15a.

Note that the other configurations are the same as those of the above-mentioned conventional device, and the description thereof will be omitted.

Next, this effect will be explained. According to this invention, gas is constantly introduced into the working chamber of the pump by the volume of the space 16 created by the notch step 15a of the vane groove 15 and the notch step 7a of the vane 7. The degree of vacuum in the vacuum tank 11 prevents it from entering the noise generation zone. That is, the vacuum characteristic curve in this case generally becomes as shown in FIG. 4C, and the noise level decreases as shown in FIG. 5B.

In the above embodiment, the notch steps 7a and 15a are provided in the vane 7 and the vane groove 15, but the notch step 15a of the vane groove may be omitted depending on the case.

[Effect of idea]

As described above, according to this invention, the notch step is provided at least on the surface of the vane tip among both surfaces corresponding in the circumferential direction between the opening of the vane groove and the vane tip. When the vane is pushed into the vane groove, gas is taken into the space created by the notch step and released in the suction zone.
Limits the degree of vacuum inside the vacuum tank, reducing noise.

Note that the degree of vacuum reached can be adjusted by the size of the notch level difference, and this notch level difference can be formed or processed at the same time as the rotor and vane are manufactured, so there is an advantage that the process can be carried out without changing costs.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional vane type pump installed on an engine, Fig. 2 is a side sectional view of the vane type pump shown in Fig. 1, Fig. 3 is a sectional view taken along the - line in Fig. 2, and Fig. 4 is a sectional view taken along the - line in Fig. 2. Figure 5 is a vacuum characteristic curve diagram, Figure 5 is a noise level measurement curve diagram, Figure 6 is a side cross-sectional view of a vane type pump showing an embodiment of this invention, and Figure 7 is a diagram of the noise level measurement curve.
It is a sectional view taken along the - line in the figure. In the figure, 1 is a bracket rear, 2 is a shaft, 3 is a bearing, 4 is a rotor, 5 is a housing, 7 is a vane,
7a is a notch step, 10 is an inlet, 11 is a vacuum tank, 12 is an outlet, 13 is an oil supply port, 15 is a vane groove, 15a is a notch step, and 16 is a space. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] a housing formed into a cylindrical shape having an inlet, an outlet, and an oil supply port; a shaft provided in the housing eccentrically with respect to the inner circumferential surface of the cylindrical portion; and a bracket rotatably supporting the shaft; The rotor is fixed concentrically to the shaft, and the vane is slidably inserted in the vane groove of the rotor in the radial direction, and as the rotor rotates, the vane comes into sliding contact with the inner circumferential surface of the cylindrical portion of the housing. In a vane-type pump that is rotated by the suction port, vacuums the gas, and discharges the gas from the discharge port, the vane groove opening of the rotor and the tip of the vane correspond to each other in the circumferential direction. A notch step is provided at least on the surface of the tip of the vane, and the vane is pushed into the vane groove in the discharge zone on the discharge port side, and the notch step makes the inner circumferential surface of the cylindrical portion A vane-type pump characterized in that a space is formed between the vane-type pumps.