JPS6242155Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a vacuum pump, particularly a vane-type vacuum pump, which is directly connected to, for example, an automotive alternator and forms a vacuum source for operating a brake booster.

In general, conventional pumps of this kind have an eccentric rotor housed in a cylinder, and this rotor is provided with a plurality of vanes slidable in the radial direction in sliding contact with the inner peripheral surface of the cylinder. A vacuum is obtained by transferring and discharging gas in an air supply chamber surrounded by the rotor and the vanes by the rotation of the rotor. In this vane type vacuum pump, oil is supplied into the cylinder for lubrication and airtightness, and is discharged from the exhaust port together with the gas.

By the way, in conventional pumps of this type, the pressure in the air supply chamber before exhaust is a fairly high vacuum during operation, while the pressure in the exhaust port chamber is atmospheric pressure, so the air supply chamber is If the tip of the vane to be formed is rotated near or above the exhaust port,
In order to balance the pressure difference between the air supply chamber and the exhaust port chamber, air or oil flows back from the exhaust port into the high vacuum air supply chamber, and as a result, oil discharge is suppressed and the exhaust port chamber is covered with an oil film. It is blocked by When this exhaust port chamber is blocked with an oil film, it is further filled with oil, and the air does not flow into the air supply chamber from the exhaust port, and only a large amount of oil flows back toward the air supply chamber. Therefore, this large amount of oil that flows back pushes up the vanes and causes them to vibrate in the radial direction.
This has disadvantages in that it reduces the durability of the vane and generates unpleasant noise from the pump.

This idea was made to eliminate the above-mentioned drawbacks, and by providing a dividing member that divides the exhaust port of the cylinder in the circumferential direction so that the vanes sequentially face each other as the vanes rotate, a large amount of lubrication can be achieved. To provide a vacuum pump that prevents backflow of material.

An embodiment of the present invention will now be described with reference to the accompanying drawings. In Fig. 1 and Fig. 2, 1 is a shaft driven by a motor (not shown), 2 is a cylindrical cylinder in which the shaft is eccentrically housed, 3 is a bearing for rotatably supporting the shaft, 4 is a bracket for supporting the bearing and fixed integrally with the cylinder 2,
5 is fixed to the shaft 1, and the cylinder 2
The rotor rotates eccentrically inside the rotor, and 6 is a number of rotors (four in FIG. 2) arranged radially on the rotor.
The vane insertion groove 7 is fitted with the vane so as to be slidable in the radial direction, the rotor 5 is provided with through holes 8, and the cylinder 2 is provided with a through hole 9.
The cylinder 2 is connected to an oil pump (not shown) through an oil supply port drilled in the cylinder 2.
The inner peripheral surface 11 of the rotor 5 and the outer peripheral surface of the vane 7
The cylinder 2 is attached to the bracket 4 by a mounting bolt 10.
Reference numeral 12 denotes an oil seal for preventing oil leakage from the cylinder 2. Reference numeral 13 denotes an intake port provided in the cylinder 2, 13a denotes an intake chamber formed by the cylinder 2 and the vane 7, 14 denotes an exhaust port provided on the opposite side of the intake port 13 of the cylinder 2, 15 denotes a discharge port open to the atmosphere, 14a denotes an exhaust port chamber sandwiched between the exhaust port 14 and the discharge port 15, 16 denotes a valve provided between the intake port 13 and the intake chamber 13a, 17 denotes a valve provided between the intake port 13 and the intake chamber 13a, and 18 denotes a valve provided between the intake port 13 and the intake chamber 13a.
The vanes 7 are provided in the exhaust port chamber 14a, and the exhaust port 14 is arranged so that the vanes 7 face each other in sequence as the vanes 7 rotate.
It is a partition member that divides the rotor into two in the circumferential direction and is configured by attaching a cylindrical member.

Next, the operation of the pump with the above configuration will be explained.
When the shaft 1 is driven in the direction of the arrow in FIG.
slide. Therefore, the vane 7 is inserted into the vane insertion groove 6.
reciprocates in the radial direction. Also, the intake chamber 13a
As the vane 7 slides and rotates with the rotation of the rotor 5, the gas moves in the direction of the arrow in the air supply chamber 2b and is gradually compressed. Chamber 14a and discharge port 1
5 to the outside air.

By repeating this operation, the gas in the intake chamber 13a is discharged, and this intake chamber 13a exhibits a high degree of vacuum.Next, the valve 16 opens due to the pressure difference between this intake chamber 13a and the intake port 13, and the intake port 13, a high vacuum is obtained. After that, when both the intake chamber 13a and the intake port 13 become high vacuum and the pressure difference disappears, the valve 1
6 is opened, and the intake chamber 13a is maintained at a high vacuum.
In this state, the gas in the air supply chamber 2b that communicates with the intake chamber 13a exhibits a high degree of vacuum, and when this gas rotates and reaches the position of the air supply chamber 2a, the gas in the air supply chamber 2b communicates with the air intake chamber 13a.
Since the degree of vacuum decreases only to a value determined by the volume ratio of a and 2b, the degree of vacuum at the position of the air supply chamber 2a also becomes considerably high. Next, when the vane 7 approaches the vicinity of the exhaust port 14, oil for lubrication and airtightness flows into the exhaust port chamber 14.
It is discharged to a. This oil is removed from the vane 7 at the exhaust port 1.
4 and fills the exhaust port chamber 14a, but in the embodiment of this invention, the cylindrical member 17 communicating with the atmosphere outside the pump
Since it opens into the air supply chamber 2a and the exhaust port 14, gas at atmospheric pressure from outside is supplied to the air supply chamber 2a through this cylindrical member 17, and a large amount of oil is removed. backflow of water can be prevented.

This point will be explained in detail below using FIGS. 3 and 4. First, as shown in FIG. 3a, an oil film 1 is formed in the exhaust port chamber 14a due to the surface tension of the oil.
8a and 18b are formed, when the vane 7a approaches the opening of the cylindrical member 17, since the air supply chamber 2a is in a high vacuum state, the inside of the cylindrical member 17 is removed as shown in FIG. 3b. The oil 18a will be sucked into the air supply chamber 2a. At this time, the cylindrical member 17
Since the amount of oil inside is relatively small, the atmosphere is also sucked into the air supply chamber 2a as shown in Figure 4a, and the pressure difference between the air supply chamber 2a and the atmosphere is large. , the inside of the air supply chamber 2a instantly becomes atmospheric pressure. Note that the oil 18a in the cylindrical member 17 is
When flowing back to a, it acts in the direction of pushing up the vane 7a, but because the amount of oil is small, it does not push up the vane 7a, and since the air is a compressible fluid and flows in from even the slightest gap, it pushes up the vane 7a. It will not work until then. Furthermore, at this time, the oil 18 in the exhaust port chamber 14a exceeds the cylindrical member.
It is conceivable that the oil 18a flows back toward the air supply chamber 2a, but the oil 18a flows through the gap between the rotor 5 and the cylindrical member 17 and acts in the direction of being pushed back by the advancement of the vane 7a. , the backflow amount is small compared to the oil 18a in the cylindrical member 17, and there is no risk of pushing up the vane 7a.

Next, when the vane 7a crosses the cylindrical member 17,
At this moment, the inside of the air supply chamber 2a is already at atmospheric pressure, so the oil 18b in the exhaust port chamber 14a hardly flows back toward the air supply chamber 2a, pushing up the vane 7a. Never.

Next, when the vane 7b rotates in the direction of the exhaust port 14, the atmosphere inside the air supply chamber 2a is pushed out as shown in FIG. 4b, and the oil 18a that has flowed into the air supply chamber 2a and Oil 18 remaining in 14a
b is also discharged to the outside from the discharge port 15 at the same time. (See Fig. 4c.) In this way, oil films 18a, 18 are formed in the exhaust port chamber 14a.
Even if the oil film b is formed, it is sequentially discharged to the outside, and it is also possible to prevent the vane 7 from being pushed up by the oil films 18a and 18b. As a result, the noise of the pump can be significantly reduced compared to the conventional pump, as shown in FIG.

In the above embodiment, one end of the cylindrical member 17 opens directly from the discharge port 15 to the atmosphere outside the pump. One end of the member 17 may be open to the outside atmosphere. Further, the equivalent function of the cylindrical member 17, that is, a partitioning member for dividing the exhaust port chamber 14a in the rotational direction of the vane 7 may be provided integrally with the exhaust port chamber 14a or the exhaust joint.

As mentioned above, this invention is a system in which a partitioning member is provided in the exhaust port chamber to divide the exhaust port in the circumferential direction so that the vanes face each other sequentially as the vanes rotate. Therefore, high-pressure fluid can be introduced into the air supply chamber through one of the exhaust port chambers, reducing the back flow of oil and preventing vibration of the vanes, thereby reducing vane wear and pump noise. becomes possible.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of a vacuum pump according to the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Figs. 3 and 4 are operations of an embodiment of the invention. The explanatory diagram, FIG. 5, is a characteristic diagram showing the noise of the device according to this invention and the conventional device. In the figure, 1 is the shaft, 2 is the cylinder, 2a, 2
b is the air chamber, 3 is the bearing, 4 is the bracket,
5 is a rotor, 6 is a vane insertion groove, 7 is a vane, 8
is a through hole, 9 is a fuel filler port, 10 is a mounting bolt, 11
is the inner peripheral surface of the cylinder 2, 12 is an oil seal, 13 is an intake port, 13a is an intake chamber, 14 is an exhaust port, 14a is an exhaust port chamber, 15 is a discharge port, 16 is a valve, and 17 is a partition member. . Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] A cylindrical cylinder having an intake port and an exhaust port, a rotor mounted eccentrically within this cylinder, and a rotor that is slidably fitted in the radial direction of the rotor, and as the rotor rotates, the inner periphery of the cylinder A vane that slides on a surface to force fluid to flow from the intake port to the exhaust port to form a vacuum on the intake port side, a lubricant that is supplied into the cylinder and smoothes rotation of the vane, and the cylinder. an exhaust port chamber formed in communication with the exhaust port of the exhaust port, provided in this exhaust port chamber,
A vacuum pump characterized by comprising a partitioning member that divides the exhaust port in the circumferential direction so that the vanes sequentially face each other as the vanes rotate.