JPS6337504Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a vacuum pump device.

First, this type of conventional device will be explained with reference to FIGS. 1, 2, and 3. In the figure, 1 is a bracket rear, 2 is a shaft supported by this bracket rear 1 via a bearing 3 and driven by an engine 14, 4 is a rotor fixed to this shaft 2 by spline fitting, and 5 is a shaft. 2 and a housing having a cylindrical inner peripheral surface eccentric to the center of the rotor 4; 6 a bolt for fixing the housing 5 to the bracket rear 1; 7 a groove 15 arranged radially on the rotor 4;
The vane is slidably inserted in the radial direction. Also, 8 is the bracket rear 1 and the housing 5.
9 is an oil seal that is fixed to the bracket rear 1 and keeps the working chamber of the pump airtight by sliding on the shaft 2; 10 is an inlet provided in the housing 5; tank 11
It is connected to the. 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 vanes 7 causes the vanes 7 to fly outward and rotate while sliding on the inner circumferential wall of the housing 5.
The air inside is sucked in and discharged from the outlet 12 to perform a pumping action. On the other hand, oil supplied into the housing 5 from the oil supply port 13 lubricates the sliding surfaces of the vanes 7 and the rotor 4, and is discharged from the discharge port 12 to the oil pan.

By the way, this type of vacuum pump device generates abnormal noise when the pressure inside the vacuum tank 1 becomes high vacuum.

In FIG. 4, A is a vacuum characteristic curve of a conventional vacuum pump device, and B is a noise generation zone. In addition, in FIG. 5, a is the vacuum tank 11
The figure shows the measured noise level when the pressure is within the noise generation zone.

The causes of this noise are the dimensions of each part of the pump, the shape of the vane, the position and shape of the inlet and outlet,
It depends on many factors such as the amount of oil supplied, and although various countermeasures have been tried, none of them have been very effective.

Also, if the pressure inside the vacuum tank is lowered below the noise generation zone, the noise level will be reduced by curve b in Figure 5.
Experimental results have proven that the vacuum tank can be reduced by as much as There were problems such as what to do.

This idea was made in order to eliminate the above-mentioned drawbacks, and the rotor has a structure in which a groove for taking in outside air is provided in the axial direction on the outer peripheral surface between adjacent vane grooves. By introducing outside air contained within the pump into the working chamber of the pump, the pressure within the vacuum tank is prevented from becoming a high vacuum, thereby reducing noise.

An embodiment of this invention will be described below with reference to FIGS. 6, 7, and 8.

In the figure, reference numeral 16 denotes a groove section provided in the axial direction on the outer circumferential surface between the vane grooves 15 of the rotor 4, and the other configurations are the same as those shown in FIGS. 2 and 3.

With this configuration, when the rotor 4 rotates, the air in the vacuum tank is discharged to the exhaust port 10 through the working chamber formed by the inner circumferential surface of the housing 5, the outer circumferential surface of the rotor 4, and the pair of vanes 7. However, as shown in Fig. 7, the rotor 4
Outside air is accommodated in the groove 16 at the portion where the outer circumferential surface of the housing 5 contacts the inner circumferential surface of the housing 5, and as the rotor 4 rotates, this air is introduced into the working chamber. It is possible to suppress an increase in the degree of vacuum in the room. Here, the upper limit of the degree of vacuum can be adjusted by the size and number of grooves 16.

Therefore, as shown by the vacuum characteristic curve c in FIG. 4, the degree of vacuum in the vacuum tank could be maintained below the range of the noise generation zone, and noise reduction could be achieved. In addition, since the groove portion 16 is formed in the same axial direction as the vane groove 15 and spline groove of the rotor 4, it is possible to mold it when molding the rotor 4, and there is no need to use special equipment, so the vacuum pump Another advantage is that the device can be made cheaper and less noisy.

In addition, in the above-mentioned embodiment, the groove portion 16 is connected to the rotor 4.
Although it is provided over the entire axial length of the The same effect can be obtained even if it is provided only in the section.

As described above, according to this invention, it is possible to limit the degree of vacuum in the vacuum tank by simply providing a groove for air intake in the axial direction on the outer peripheral surface between adjacent vane grooves of the rotor. This makes it possible to obtain an inexpensive vacuum pump device with less noise.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a state in which a conventional vacuum pump device is attached to an engine, Fig. 2 is a side sectional view showing a conventional vacuum pump device, Fig. 3 is a sectional view taken along the - line in Fig. 2, and Fig. 4 The figure is a vacuum characteristic curve diagram, Figure 5 is a noise level measurement curve diagram, Figure 6 is a side cross-sectional view showing a vacuum pump device that is an embodiment of this invention, and Figure 7 is a cross-sectional view taken along the - line in Figure 6. Figure 8 is a perspective view of the main parts in Figure 6, Figure 9, Figure 1.
0 and 11 are perspective views of main parts showing other embodiments of this invention. 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,
10 is an intake port, 11 is a vacuum tank, 12 is an exhaust port, 13 is a fuel filler port, 14 is an engine, 15 is a vane groove, and 16 is a groove portion. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A housing that has an inlet, an outlet, and a refueling port, and has a cylindrical inner surface; a shaft that is eccentric to the center of the cylindrical inner surface of the housing; and a shaft that is rotatable. A supporting bracket, a rotor eccentric to the center of the cylindrical inner circumferential surface of the housing and fixed to the shaft, and a plurality of vane grooves formed on the outer circumferential surface of the rotor are slidably inserted in the radial direction. and a plurality of vanes capable of slidingly contacting the cylindrical inner circumferential surface of the housing to forcefully convey gas from the inlet to the outlet, wherein a plurality of vanes are provided on the outer circumferential surface between adjacent vane grooves of the rotor, respectively. A vacuum pump device characterized by having a groove for taking in outside air in the axial direction.