JPH045751Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to an improvement in the opening shape of the inlet or outlet of a two-shaft Roots-type blower, and is generally used in compressors, blowers, and is used in superchargers for automobile internal combustion engines.

(Prior Art) As a prior art related to the present application, a general two-shaft Roots type blower has an inlet port 3 and a discharge port 4 as shown in FIG.
a housing 1 having on opposite sides, the shafts 5 and 6 of which are pivoted in the housing inner chamber 2, and the shafts 5 and 6 are
It consists of two rotors 7, 8 which operate functionally in the direction.

The shape of the opening 40 of the discharge port 4 of this blower is A
When viewed from the arrow, it has a rectangular shape as shown in FIG. 2 or a circular shape as shown in FIG. 3. Therefore, looking at the relationship between the rotor tip 71 marked by the two-dot chain line and the shape of the opening 40, when the rotor tip 71 passes through the upper side 41 of the rectangle in FIG. The working length is
In addition, in the circle shown in FIG. 3, the top 42 is connected to the rotor tip 71.
passes through the opening 4, the dimension a gradually increases in length, and the opening 4
It becomes the length of action towards 0 and changes the opening area.

The two-shaft Roots type blower sucks fluid from the suction port 3 side into the discharge port 4 side through a small chamber 21 formed by the rotor 7 and the housing 1, but the suction port 3 side is generally at atmospheric pressure. Therefore, the inside of the small chamber 21 is also at atmospheric pressure. The main part of this atmospheric pressure state is supplied to the compressed pressure side of the discharge port 4 side.

(Problem to be solved by the invention) By the way, in the conventional discharge opening shape described above, since the action length a of the rectangular one is constant, the opening initial stage (that is, the rotor tip 71 is
1), the aperture area increases linearly and rapidly. As a result, pressure changes may occur suddenly, producing knocking noises, or uneven loads due to pressure changes may suddenly act on the rotor 7 or shaft 5, causing uneven wear on the pivot portion of shaft 5, resulting in poor durability and precision. cause problems.

Further, problems similar to those of the discharge port 4 occur with the suction port 3 as well. That is, when the suction port 3 is rectangular, the small chamber 21 is instantly sealed at the end of the intake stroke, and a closing sound such as "buff" is generated at the suction port 3.

Furthermore, when the discharge port opening is circular in shape, the action length a changes sequentially, so when the axial length b of the rotor is approximately equal to the diameter of the circular opening, problems similar to those that occur with rectangular ones arise. However, in general, a rotor whose axial length b is considerably longer than the diameter of the circular opening is used, and since the absolute area is small, it is difficult to efficiently supply the fluid in the small chamber 21 to the discharge port. The problem arises that it is not possible. This problem is exactly the same for the inlet 3 as well.

Utility Model Application Publication No. 2256 of 1942 and Japanese Patent Laid-Open No. 51-27110 disclose a Roots-type blower in which the opening shapes of the inlet and discharge ports are changed in order to solve the above-mentioned problems. ing.

In Utility Model Application Publication No. 2256 of 1947,
As shown in FIG.
The sealing sound generated at the opening 30 is reduced by protruding. However, since the apex 32 of the chevron portion 31 has weak mechanical strength and stress is concentrated thereon, there is a problem in the durability of the apex 32. Furthermore, if the chevron portion 31 protrudes from the opening 30,
Another problem is that the fluid passing through the opening 30 generates abnormal noise such as so-called wind noise.

Further, in Japanese Utility Model Application Publication No. 51-27110, as shown in FIG. The shape changes sequentially over the entire range. Therefore, the absolute area of the opening 40 becomes small, and a problem arises in that the fluid in the small chamber 21 cannot be efficiently supplied to the discharge port 4.

In addition, in Utility Model Application Publication No. 14233 of 1932 and Utility Model Application Publication No. 1982-21011, in order to solve the above-mentioned problems, a roots-type blower with a different opening shape of the inlet and outlet was introduced. Disclosed.

The Roots blower disclosed in Utility Model Application Publication No. 14233 of 1932 had a trapezoidal suction port to prevent sealing noise.

Furthermore, in the blower disclosed in Japanese Utility Model Application Publication No. 52-21011, the suction port is shaped like a parallelogram tilted by A degree with respect to the axial direction of the shaft disposed inside the blower, and the discharge port is formed at the shaft end. The shape of the parallelogram is tilted A degree opposite to the suction port with respect to the axial direction, thereby preventing the occurrence of sealing noise.

However, the above-mentioned utility model application announcement in 1932
In the methods disclosed in Japanese Utility Model Application No. 14233 and Japanese Utility Model Application Publication No. 52-21011, at the portion where the rotor starts to act on the openings of the suction port or the discharge port, these openings have a portion parallel to the axial direction of the shaft. There is no Therefore, since the opening area cannot be made large, this creates resistance to the discharged fluid, resulting in inefficient supercharging.

Therefore, the present invention aims to improve the efficiency of air supply by increasing the absolute area of the opening in a roots-type blower that eliminates knocking and sealing sounds by changing the shape of the opening of the suction or discharge port. The technical problem is to increase the durability of the opening, and to suppress the abnormal noise generated at the opening.

[Structure of the idea]

(Means for solving the problem) The technical means taken to solve the above technical problem is that the opening shape of at least one of the suction port and the discharge port on the inside of the housing is The inner angle of the rotor is within 180 degrees, and the opening length in the axial direction of the rotor is smaller than the axial length of the rotor and longer than the opening length in the direction connecting the two axes, and further, In the opening,
The initial range in which the length of action of the rotor tip on the opening changes sequentially when the rotor tip passes through the opening, and the length of the action of the rotor tip on the opening is approximately equal to the axial length of the rotor. With the latter range,
Furthermore, at the position where the rotor begins to act on the opening,
The opening has a portion parallel to the axial direction, and the interior angle of the opening includes an interior angle formed by a curved surface.

(Operation) The above technical means operates as follows. That is, fluid carried by the rotor from the suction port is supplied to the discharge port. In the initial range in which the rotor tip passes through the opening, the rotor tip gradually increases the length of its action with respect to the opening of the suction or discharge port, so that the opening area changes in a quadratic curve. Therefore, sudden pressure changes do not occur, and knocking noises, sealing noises, and uneven wear are less likely to occur. Further, this working length becomes approximately the same as the length in the axial direction of the rotor after the tip of the rotor moves out of the initial range, so that the absolute area of the opening becomes large and efficient air supply becomes possible.

Furthermore, since there is no vertex protruding from the opening, stress applied to the opening is dispersed. Therefore, the durability of the opening is improved. Furthermore, since there is no part protruding from the opening, it is possible to suppress the generation of abnormal noise at the opening.

Furthermore, since there is a portion parallel to the axial direction of the opening at the position where the rotor starts acting on the opening, it is possible to maximize the area of the opening.

(Example) The following is a sixth example of an example of the above technical means.
This will be explained with a diagram.

Opening length d of the discharge port opening 40 in the rotor axial direction
is slightly smaller than the axial length b of the rotor.
The opening length e of the discharge port opening in the direction connecting the two axes is approximately the same as that between the two axes 5 and 6 in FIG. The upper side of the opening 40 has the apex 42 and has an opening length e of 4.
It has a shape that is inclined by a factor of 1/2 and reaches the opening length d. When the rotor tip 71 passes through the opening apex 42, the length a formed by the opening upper side 41 and the rotor tip 71 becomes the working length, and the opening area becomes the shaded area D.
When the rotor rotates, the rotor tip moves to 71',
The working length is c, and the opening area is the shaded area D+E. When the rotor rotates further, the working length becomes d. Here, in the initial stage of opening, the opening area increases in a quadratic curve as shown in FIG. 10F. Furthermore, the 10th
G in the figure corresponds to the conventional technology in Figure 2, and H corresponds to the conventional technology in Figure 3.
This is a characteristic equivalent to that shown in the figure.

Other embodiments are shown in FIGS. 7 to 9. FIG. 7 shows a shape that starts opening from one side. 8th
The figure shows a shape in which the apex 42 of FIG. 6 is flattened, and FIG. 9 also shows a shape that starts opening from one end.

In the embodiment of FIG.
The shape is symmetrical about the center. While the rotor tip 71 is in the initial half period i of the opening 40, the working length of the opening 40 of the rotor tip 71 gradually increases. And the tip 7 of the rotor
1 is in the latter range j of the opening 40, the length of action of the rotor tip 71 on the opening 40 is approximately the same. In addition, the inner corner 5 of the opening 40
1 is an angle within 180. Further, the interior angle 52 of the opening 40 is also substantially within 180 degrees, since the angle between the opening 40 and the tangent at any point of the curved area is within 180 degrees.

Also, in the embodiments shown in FIGS. 7 and 8, the opening 40 has a shape that is symmetrical about the center line 50,
Furthermore, the inner angles 53 to 58 have an initial range i and a later range j similar to those in FIG. 7, and are all within 180 degrees.

[Effect of idea]

According to the present invention, an initial range and a later range are provided within the opening, and in the latter range, the length of the rotor tip acting on the opening is approximately the same as the axial length of the rotor. Therefore, the absolute area of the opening becomes large, allowing efficient intake of air.

Furthermore, according to the present invention, the internal angle of the opening is within 180 degrees, and since there is no vertex that projects from the opening, stress applied to the opening is dispersed. Therefore, the durability of the opening is improved.

Further, according to the present invention, since there is no part protruding from the opening, generation of abnormal noise at the opening can be suppressed.

[Brief explanation of drawings]

Fig. 1 is a diagram of the prior art that is the basis of the present invention, Fig. 2 is a view from A of the opening of the discharge port in Fig. 1, Fig. 3,
Figures 4 and 5 are opening views of other conventional techniques, and Figure 6 is
The figures are explanatory diagrams of the opening according to the present invention, Figures 7 to 9.
Figure 10 is an opening diagram of another embodiment of the present invention.
The figure is a characteristic diagram showing the relationship between the rotor rotation angle and the opening area. 1... Housing, 3... Suction port, 4... Discharge port, 7, 8... Rotor, 30, 40... Opening,
51-58...Interior angle, b...Rotor axial length, d...Rotor axial opening length, e...Opening length in the direction connecting the two axes, i...Initial range, j...
Late range.

Claims (1)

[Claims for Utility Model Registration] (1) A two-shaft root consisting of a housing having an inlet and an outlet on opposite sides, and two functionally operating rotor parts whose shafts are pivoted in the inner chamber of the housing. In the type blower, an opening shape of at least one of the suction port and the discharge port on the inside of the housing is configured such that the internal angle of all the openings is within 180 degrees, and The opening length is smaller than the axial length of the rotor, and 2
The opening has a flat shape that is longer than the length of the opening in the direction connecting the shafts, and the opening has an initial shape in which the length of the rotor tip acting on the opening changes sequentially when the rotor tip passes through the opening. and a later range in which the length of the rotor tip acting on the opening is approximately the same as the axial length of the rotor, further comprising: a position where the rotor starts acting on the opening;
A roots-type blower having a portion parallel to the axial direction of the opening. (2) The roots-type blower according to claim 1, wherein the internal angle of the opening includes an internal angle formed of a curved surface.