JP2002106489A - Sealing structure for fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing structure for fan high in the effect of suppressing a reverse flow around the vanes and easy in its assembly. SOLUTION: A stepped labyrinth seal part 12 composing this sealing structure is provided with a ring 5 connecting front end edges of a plurality of vanes mutually and the cylindrical part 7 of a shroud 6 arranged spacing outside in the radial direction of the ring. A throttle piece S is projectingly provided on the outer periphery of the ring 5, and the stepped floor faces F1 and F2 are formed on the inner periphery of the cylindrical part 7. Further, a reverse throttle piece R is provided on the floor face F1 in such a form as not to interfere with the insertion of the ring 5 in an axial direction into the cylindrical part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial or mixed flow type fan sealing structure used for cooling a radiator of an automobile and the like. More particularly, the present invention relates to a boss having a plurality of blades provided radially on a boss. The present invention relates to a fan seal structure in which a step-shaped labyrinth seal portion is provided between a ring to be interconnected and a cylindrical portion of a shroud disposed radially outside the ring.

[0002]

2. Description of the Related Art An axial-flow or diagonal-flow fan used for cooling a radiator of an automobile is provided with a plurality of blades radially provided on a boss portion rotated by a driving source such as an engine or a motor. The air is blown in the axial direction by the rotation of. In general, in an axial or mixed flow fan, there is a phenomenon that a part of the airflow to the downstream side flows backward from the blade periphery to the upstream side. Such a backflow phenomenon is not preferable because it lowers the blowing efficiency and increases noise. Therefore, a shroud is conventionally arranged so as to surround the radially outer side of the blade, thereby suppressing backflow.

However, if the purpose of suppressing the backflow can be achieved only by providing the shroud, a seal portion is further provided between the blade and the shroud. FIG. 4 is a longitudinal sectional view of a conventional mixed flow fan for cooling a radiator mounted on an automobile. The fan 1 includes a drive shaft 2 rotated by a crankshaft of an engine (not shown), and a boss 3 fixed to the drive shaft 2.
And a plurality of blades 4 provided radially, and the blades 4 rotate to blow air from the left side to the right side in the drawing of FIG. The tips of the wings 4 are connected to each other by a ring 5, and a cylindrical portion 7 of a shroud 6 is arranged with a predetermined gap so as to surround a radial outside of the ring 5. A plurality of aperture pieces S such as annular partition pieces are provided at predetermined intervals along the outer periphery of the ring 5. In this example, a ring-shaped bell mouth M which suppresses turbulence of air flow and generation of vortex at both axial ends of the ring 5 is described.
The bell mouth M also serves as the aperture pieces S at both ends.

On the other hand, the shroud 6 is bolted to a cylindrical connecting body 8 at its flange portion, and the connecting body 8 is fixed to a radiator 9. The inner peripheral surface of the cylindrical portion 7 faces the ring 5 with a predetermined gap, and a so-called direct labyrinth seal portion 10 is formed by the inner peripheral surface and the plurality of throttle pieces S of the ring 5. In such a direct-type labyrinth seal portion 10, a throttle port is formed by the gap between the inner peripheral surface of the cylindrical portion 7 and the tip end of the throttle piece S, and the downstream side of the blade 4 (the blade in FIG. 4 (right side of FIG. 4) undergoes isentropic expansion when passing through the throttle port, and the decelerated reverse flow is a space (expansion chamber) in the middle of the adjacent throttle piece S.
, The sealing effect is exhibited by repeating the action of restoring to a static temperature at an equal pressure.

However, although the direct-type labyrinth seal portion 10 has a simple structure, a blow-through passage is formed in the gap between the inner peripheral surface of the cylindrical portion 7 and the tip end of the throttle piece S, and there is a problem that the backflow easily occurs. . The staggered labyrinth seal portion improves on this and further enhances the effect of suppressing backflow.
FIG. 5 is a partially enlarged cross-sectional view in which a staggered labyrinth seal portion 11 is employed in place of the direct through labyrinth seal portion 10 in the seal structure of FIG. 4, and the same reference numerals are given to the same portions as FIG. Have been. The staggered labyrinth seal portion 11 is provided with a plurality of throttle pieces S on the outer peripheral surface of the ring portion 5 and is opposite to the inner peripheral surface of the cylindrical portion 7 of the shroud 6 so as to protrude to an intermediate portion of the throttle pieces S. The aperture piece R is provided. For the sake of simplicity, in the drawing, a staggered labyrinth seal portion 11 is represented by two throttle pieces S provided at both ends in the axial direction of the ring 5 and one reverse throttle piece R provided at an intermediate portion thereof. However, in practice, more diaphragm pieces S and reverse diaphragm pieces R are provided.

The staggered labyrinth seal portion 1 shown in FIG.
In 1, since the restricting pieces S and the reverse restricting pieces R are alternately arranged in the radial direction, the reverse flow is meandering between the restricting piece S and the reverse restricting piece R as shown by an arrow, and a part of the reverse flow is divided. Since the backflow is decelerated by forming a vortex, the backflow is more effectively suppressed than the direct-flow labyrinth seal portion 10. However, when the throttle piece S and the reverse throttle piece R are arranged so as to overlap each other in the radial direction, the ring portion 5 is inserted into the cylindrical portion 7 of the shroud 6 from the axial direction as shown by the arrow B, and the sealing portion is formed. Another problem arises in that it is difficult to assemble. In the present invention, the axial direction refers to the axial direction of the drive shaft 2 in FIG.

FIG. 6 is a partially enlarged cross-sectional view in which a step-type labyrinth seal portion 12 is used instead of the direct-type labyrinth seal portion 10 in the seal structure of FIG. 4, and the same portions as those in FIG. Reference numerals are given. The step-type labyrinth seal portion 12 is formed by the cylindrical portion 7 of the shroud 6.
Two floor surfaces F (F
1, F2), and the floor surface F1 located on the upstream side in the reverse flow direction (arrow D) protrudes radially from the floor surface F2 on the downstream side. The diaphragm pieces S (S1, S2) provided on the outer periphery of the ring 5 facing the floor surface F1 and the floor surface F2 respectively correspond to the floor surfaces F1, F2.
The height of the ring 5 is inversely proportional to the length of the protrusion, and the ring 5 can be mounted on the cylindrical portion 7 from the axial direction. In many cases, the practical stair-type labyrinth seal portion 12 has many floor surfaces F. However, in FIG. 6, only two floor surfaces F1 and F2 are representatively shown to simplify the description.

[0008]

The conventional step-type labyrinth seal portion 12 shown in FIG. 6 is characterized in that the reverse flow rate can be made smaller than that of the direct-type labyrinth seal portion 10 and that the assembly of the seal portion is easy. However, there is a problem that the dimension in the radial direction is increased. That is, in order to obtain the same sealing effect as that of the staggered labyrinth seal portion 11 as described above, the height of the throttle piece S1 is h1, and the gap from the tip of the throttle piece S1 to the floor surface F1 is C.
1. Assuming that the height of the diaphragm S2 is h2 and the gap from the tip of the diaphragm S2 to the floor surface F2 is C2, h2> h1 + C1
It is necessary to set the level difference Rh1 to about three times C1 or C2 under the conditions described above. However, the value of 3 times may not be practically acceptable, and is often set to 3 times or less in response to a corresponding increase in the backflow. Therefore, an object of the present invention is to suppress an increase in the dimension in the radial direction while maintaining the characteristics of the step-type labyrinth seal portion 12, and to provide a new fan seal structure for that purpose.

[0009]

That is, the present invention is an axial or mixed flow type fan sealing structure in which a plurality of blades 4 are radially provided on a boss 3. The seal structure includes a ring 5 that connects the tips of the blades 4 to each other, and a tubular portion 7 of a shroud 6 that is arranged with a gap radially outside the ring 5. A step-shaped labyrinth seal portion is formed by an annular throttle piece S protruding along the axis and a floor surface F having a step in the axial direction provided along the inner periphery of the cylindrical portion 7. The reverse drawing piece R is provided on the floor surface F in such a manner as not to hinder the axial insertion of the ring 5 into the shaped part 7 (claim 1).

In the above-mentioned sealing structure, the reverse throttle piece R is formed at a height that does not overlap in the radial direction with the throttle piece S located on the upstream side in the reverse flow direction, so that the ring 5 can be inserted into the cylindrical portion 7 in the axial direction. The reverse drawing piece R can be provided on the floor surface F in an unobstructed manner (claim 2). In the above-mentioned seal structure, while the throttle pieces S1 and S2 are provided on the outer periphery of the ring 5, floor surfaces F1 and F2 having steps in the axial direction are provided on the inner circumference of the cylindrical portion 7, and the throttle pieces S
1 and S2, a reverse stop piece R is provided on the floor surface F1 so as to protrude there between, and the height of the stop piece S1 is h1, the stop piece S
C1 is the gap from the front end of F1 to the floor surface F1,
2 is h2, the gap from the tip of the diaphragm S2 to the floor surface F2 is C2, the height of the reverse diaphragm R is Rh2, and the diaphragm S is
Assuming that the height difference between the tip of No. 2 and the tip of the reverse diaphragm piece R is Δh, a configuration satisfying the condition of 0 <Δh <Rh2 <C1 can be achieved.

Further, in the above-mentioned sealing structure, the throttle piece S
In addition, by making at least one of the reverse drawing pieces R elastically deformable in the axial direction, the reverse drawing piece R is placed on the floor surface F in a form that does not hinder the axial insertion of the ring 5 into the cylindrical portion 7.
(Claim 4).

[0012]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows an example of the seal structure of the present invention in FIG.
FIG. 7 is a partially enlarged cross-sectional view shown in accordance with FIG. The step-type labyrinth seal portion 12 is applied as a fan seal structure shown in FIG. 4, and includes a ring 5 that connects the tips of the blades 4 to each other,
A cylindrical portion 7 of a shroud 6 is provided with a gap radially outside the ring 5. The ring 5 has two annular throttle pieces S at both axial ends along its outer periphery.
(S1, S2) are protruded, and annular floor surfaces F1, F2 which are stepped in the axial direction are formed on the inner peripheral portion of the cylindrical portion 7, and are located on the upstream side in the reverse flow direction (arrow D). Floor surface F
1 protrudes in the radial direction from the floor surface F2 on the downstream side. Further, an annular reverse throttle R is protruded from an inner periphery of the floor surface F1 on the downstream side in the reverse flow direction.

The height of the diaphragm S1 is h1, the gap from the tip of the diaphragm S1 to the floor surface F1 is C1, the height of the diaphragm S2 is h2, and the height of the diaphragm S2 is H2.
0 <Δh <, where C2 is the gap from the floor F1, and Rh2 is the height from the floor F1 to the reverse drawing piece R, and Δh is the height difference (vertical distance) between the tip of the drawing piece S2 and the tip of the reverse drawing piece R. R
Under the condition of h2 <C1 (1), both the insertability in the axial direction (assemblability) and the blocking property of the blow-through passage by the reverse throttle R and the throttle S2 are satisfied. That is, by setting the height of the reverse drawing piece R to be Rh2 <C1, the reverse drawing piece R is formed so that the ring 5 can be inserted into the cylindrical portion 7 in the axial direction, and the relation of 0 <Δh <Rh2 <C1 is satisfied. As a result, the blocking property of the passage passage is ensured.

At this time, since the condition of h1 <h2 <h1 + C1 (2) only needs to be satisfied, the height of h2 is smaller than the condition of h2> h1 + C1 in the conventional step-type labyrinth seal portion 12 shown in FIG. The size can be reduced, and an increase in the dimension in the radial direction can be suppressed. In addition, by providing the reverse throttle R, a vortex is formed downstream of the reverse throttle R to further reduce the reverse flow, as in the staggered labyrinth seal portion 11 shown in FIG. Can be suppressed.

FIG. 2 is a partially enlarged sectional view showing another example of the seal structure of the present invention in accordance with FIG. 1, and the same parts as those in FIG. 1 are denoted by the same reference numerals. In this example, three annular floor surfaces F1, F2, F3 having a step in the axial direction are formed on the inner periphery of the cylindrical portion 7, and are upstream from the floor surface F3 located on the downstream side in the reverse flow direction (arrow D). Side floor surface F
The radial protrusion amount increases in order toward 1. The ring 5 is provided with four annular throttle pieces S (S1 to S4) protruding along the outer periphery thereof.
1, the aperture pieces S2 and S3 are disposed opposite to the floor surface F2, and the aperture piece S4 is disposed opposite to the floor surface F3, and their heights are values inversely proportional to the protrusion amounts of the floor surfaces F1 to F3.

The floor surfaces F1 and F2, the stop pieces S1 and S2 and the reverse stop R in FIG. 2 correspond to the floor surfaces F1 and F2, the stop S1 and S2 and the reverse stop R in FIG. 1, respectively. The mutual dimensional relationship and operation are the same as in FIG. However, in this example, since the throttle pieces S3 and S4 are added, the effect of suppressing the backflow increases accordingly.
In FIG. 2, a new reverse stop piece R is replaced by stop pieces S2 and S
3 and can be provided on the floor surface F2. In this case, the dimensional relationship between the stop pieces S2 and S3 and the new reverse stop piece R may be set in accordance with the dimensional relationship between the three stop pieces S1 and S2 and the reverse stop piece R in FIG. The same applies to the case where more diaphragm pieces S and reverse diaphragm pieces R are provided along the axial direction.

FIG. 3 is a partially enlarged sectional view showing another example of the seal structure of the present invention in accordance with FIG. 2, and the same parts as those in FIG. 2 are denoted by the same reference numerals. In this example, the annular reverse throttle piece R provided on the floor surface F1 is elastically deformable in the axial direction. Here, the term “elastic deformation” refers to a property of deforming when a stress is applied, returning to the original state when the stress is removed. In order to make the reverse drawn piece R elastically deformable, it may be made of a soft elastic material such as soft plastic or rubber, or a part of the reverse drawn piece R may be cut or cut so as to be easily deformed. Instead of or together with the reverse diaphragm R, the diaphragm S can also be made elastically deformable. Note that the cylindrical portion 7 is made of a hard material,
When is made of a soft elastic material, they are fixed by bonding or the like. Also, when the ring 5 is made of a hard material and the squeezing piece S is made of a soft elastic material, the two are fixed by bonding or the like.

When at least one of the reverse stop piece R and the reverse stop piece S is formed so as to be elastically deformable in the axial direction, even if the stop piece S and the reverse stop piece R overlap each other in the radial direction as shown in FIG. Due to the deformation, the ring 5 can be easily inserted into the cylindrical portion 7 from the axial direction. In addition, by making the throttle piece S and the reverse throttle piece R overlap each other in the radial direction, it is possible to obtain a seal structure having a high backflow suppressing effect of the staggered labyrinth seal 11 while maintaining the shape of the stepped labyrinth seal 12. it can.

[0019]

As described above, the seal structure of the fan according to the present invention comprises a ring connecting the tips of the blades to each other, and a tubular portion of the shroud arranged with a gap radially outside the ring. This forms a stair-shaped labyrinth seal,
A reverse drawing piece is provided on the floor surface of the cylindrical portion so as not to hinder the axial insertion of the ring into the cylindrical portion. Therefore, it is possible to suppress an increase in the dimension in the radial direction without impairing the high backflow suppression effect inherent in the step-type labyrinth seal portion and the ease of assembling the seal portion.

In the above-mentioned sealing structure, when the reverse throttle piece and the throttle piece located on the upstream side in the reverse flow direction are configured not to overlap in the radial direction, the reverse throttle piece does not hinder the axial insertion of the ring into the cylindrical portion. It is provided on the floor surface in the form.
Furthermore, in the above-mentioned sealing structure, when at least one of the throttle piece and the reverse throttle piece is configured to be elastically deformable in the axial direction, the reverse throttle piece is provided on the floor surface in a form that does not hinder the axial insertion of the ring into the cylindrical portion.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view showing an example of a seal structure according to the present invention.

FIG. 2 is a partially enlarged sectional view showing another example of the seal structure according to the present invention.

FIG. 3 is a partially enlarged sectional view showing still another example of the seal structure according to the present invention.

FIG. 4A is a longitudinal sectional view of a conventional mixed flow fan for cooling a radiator mounted on an automobile, and FIG.
The A arrow view.

FIG. 5 is a partially enlarged cross-sectional view showing a conventional staggered labyrinth seal portion.

FIG. 6 is a partially enlarged cross-sectional view showing a conventional step-type labyrinth seal portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fan 2 Drive shaft 3 Boss part 4 Wing 5 Ring 6 Shroud 7 Cylindrical part 8 Connecting body 9 Radiator 10 Direct type labyrinth seal part 11 Staggered type labyrinth seal part 12 Step type labyrinth seal part M Bellmouth S Squeezing piece R Reverse drawing piece F Floor surface

Continued on front page F-term (reference) 3H022 AA03 BA02 CA33 CA34 CA54 DA07 DA08 DA20 3H033 AA02 AA15 BB02 BB07 BB08 CC04 DD10 DD26 DD27 EE05 EE08 EE09 EE13 3H034 AA02 AA15 BB02 BB07 BB08 CC04 DD05 EE08 DD25 EE08

Claims (4)

[Claims] An axial flow or mixed flow type fan sealing structure in which a plurality of blades are radially provided on a boss portion, wherein a ring connecting the tips of the blades to each other;
Shroud 6 with a gap radially outside of
A cylindrical throttle 7 having an annular throttle piece S protruding along the outer periphery of the ring 5 and a floor surface F provided along the inner periphery of the cylindrical portion 7 and having a step in the axial direction. Step type labyrinth seal part 12
The reverse seal piece R is provided on the floor surface F in such a manner as not to hinder the axial insertion of the ring 5 into the cylindrical portion 7. 2. The device according to claim 1, wherein the reverse restricting piece R and the restricting piece S located on the upstream side in the reverse flow direction do not overlap in the radial direction. A fan sealing structure in which a reverse drawing piece R is provided on the floor surface F in a form that does not hinder insertion. 3. The floor surface F according to claim 2, wherein throttle pieces S1 and S2 protrude from the outer periphery of the ring 5 and have a step in the inner periphery of the cylindrical portion 7 in the axial direction.
1 and F2 are provided, and a reverse drawing piece R is provided on the floor surface F1 so as to protrude between the drawing pieces S1 and S2. The height of the drawing piece S1 is h1, and the floor surface from the tip of the drawing piece S1 is the floor surface. The gap to F1 is C1, and the height of the throttle piece S2 is h
2. The gap from the tip of the throttle piece S2 to the floor surface F2 is C
2. A fan seal structure in which 0 <Δh <Rh2 <C1 where Rh2 is the height of the reverse drawing piece R and Δh is the height difference between the tip of the drawing piece S2 and the tip of the reverse drawing piece R. 4. The device according to claim 1, wherein at least one of the stop piece S and the reverse stop piece R is configured to be elastically deformable in the axial direction, thereby preventing the ring 5 from being inserted into the cylindrical portion 7 in the axial direction. A seal structure of a fan in which a reverse throttle piece R is provided on the floor surface F.