JPH10281094A - Centrifugal fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the leakage of fluid through a clearance between an impeller and a housing. SOLUTION: A centrifugal fluid machine comprises a compressor housing 61 having a fluid flow inlet 67 and a fluid flow outlet, an impeller 57 which is arranged rotatably inside the housing 61 and in which a shroud 117 opposed to the housing 61 and a base part 115 are interconnected through a number of vanes 119, a flange part 121 provided on the shroud 117, and a recessed part 123 on the housing 61 side into which the flange part 121 is penetrated through a clearance. In this case, it is provided with a seal to prevent the leakage of fluid through a clearance between the shroud 117 and the housing 61.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal fluid machine used as a compressor or an expander.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 4-61987 discloses a labyrinth seal 209 provided between a seal holder 205 on a housing 203 side of a centrifugal fluid machine 201 and a shroud 207 of an impeller as shown in FIG. .

The labyrinth seal 209 is composed of a sealing material 211 fixed to a seal holder 205 and a shroud 2.
07 and a tooth-shaped protrusion 213 formed at
The housing 203, the seal holder 205, and the shroud 20
7, the bypass flow 217 (fluid leakage) generated is reduced, and the efficiency of the fluid machine 201 is prevented from lowering.

The seal holder 205 is fixed to the housing 203 by bolts 219 via sliding rings 221 and 221 having low thermal conductivity, and a gap 223 is provided between the seal holder 205 and the housing 203. Have been.

In this way, the heat of the housing 203 is cut off from the seal holder 205, and the temperature of the seal holder 205 and the temperature of the shroud 207 (impeller) are always kept substantially equal. Leakage has been reduced.

[0006]

However, the labyrinth seal 209 is arranged in the direction in which the centrifugal force of the impeller works, and in the centrifugal fluid machine 201, the impeller rotates at an extremely high speed and a large centrifugal force is applied. Therefore, the shroud 207 expands due to this large centrifugal force, and the seal member 211 of the labyrinth seal 209 and the tooth-shaped protrusion 213 come into contact and wear.

Further, when the relative rotation speed between the seal member 211 and the tooth-shaped protrusion 213 increases due to the high-speed rotation of the impeller, the fluid becomes low pressure in the labyrinth seal 209, and the seal member 211 and the tooth-shaped protrusion 213 are separated. The contact and wear are promoted by the attraction, and the labyrinth seal 2 is
09 becomes large, and the sealing performance and the efficiency of the fluid machine 201 are reduced.

Further, when the sealing member 211 and the tooth-shaped protrusion 213 slide in contact with each other, they become hot due to frictional heat, and further expand and come into strong contact. In extreme cases, they may be seized.

Further, in the fluid machine 201, in order to maintain the sealing property of the labyrinth seal 209, the seal holder 205
And the housing 203 are separated from each other, and these are fixed by bolts 219 via the slide ring 221. Therefore, the structure is complicated and the number of parts is large.
High cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a centrifugal fluid machine which has a simple structure, prevents the leakage of fluid between an impeller and a housing, and improves efficiency at low cost.

[0011]

According to a first aspect of the present invention, there is provided a centrifugal fluid machine, wherein a fluid inlet and a fluid are provided at both ends of a spiral fluid flow path whose cross-sectional area perpendicular to the moving direction of the fluid changes toward one side. A housing provided with an outlet, an impeller rotatably disposed inside the housing, and connecting a shroud and a base facing the housing with a number of blades, a flange provided on the shroud, and the flange Comprises a recess on the housing side that penetrates through the gap, and is provided with a seal for preventing fluid leakage between the shroud and the housing.

As described above, in the centrifugal fluid machine according to the first aspect, the seal is formed by penetrating the flange provided on the shroud of the impeller into the recess of the housing. The fluid is accelerated in the centrifugal direction to provide a centrifugal pumping action, which prevents the leakage of fluid between the shroud and the housing.

As described above, unlike the conventional example in which the labyrinth seal is disposed in the centrifugal direction, the structure is such that the leakage of the fluid is prevented by the centrifugal pump action of the seal. Even if the impeller expands, contact between the impeller and the housing,
Heat generation and wear due to contact, fluid leakage, and the like are prevented, and the sealing performance and efficiency of the centrifugal fluid machine are kept high.

Further, since a sufficient sealing property is obtained as described above, there is no need to provide a complicated structure for connecting the housing 203 and the seal holder 205 via the sliding ring 221 as in the conventional example, and the housing is not required. Since they can be integrally formed, the structure is simplified, the number of parts is reduced, and the cost is reduced.

Also, the provision of the flange portion improves the strength of the shroud, increases the durability of the impeller against high-speed rotation, and expands the impeller due to centrifugal force.
The contact with the housing and the deterioration of the sealing performance are further reduced.

The effect of the flange for preventing the deformation of the shroud is greatest when the flange is provided at the end of the shroud.

According to a second aspect of the present invention, there is provided the centrifugal fluid machine according to the first aspect, wherein the flange is provided in a centrifugal direction near one end of the shroud, and the flange is provided on the other end of the shroud. The outer diameter is larger than the outer diameter of the flange, and the gap A between the shroud and the housing is wider than the gap B between the flange and the recess.

In this configuration, since the gap A between the shroud and the housing is made wider than the gap B between the flange portion and the concave portion, a labyrinth sealing effect is obtained in this gap B, and fluid leakage between the shroud and the housing is achieved. Is prevented.

Since the shroud is provided with the flange portion, the facing area between the flange portion forming the gap B and the concave portion can be increased, so that the labyrinth sealing effect of the gap B is large and the leakage of the fluid is reduced. Prevention.

Further, since the flange portion is formed in the centrifugal direction, unlike the conventional example in which the labyrinth seal is arranged in the centrifugal direction, the gap B is formed in a direction substantially perpendicular to the centrifugal direction, and is free from the influence of the centrifugal force. Thus, the sealing property is kept high. Thus, the same effect as that of the first aspect is obtained.

According to a third aspect of the present invention, in the centrifugal fluid machine according to the first aspect, the flange portion is provided near one end of the shroud, and the outer diameter of the other end of the shroud is reduced. It is characterized by being smaller than the outer diameter of the flange portion.

In this configuration, the leakage of the fluid between the shroud and the housing is prevented by the centrifugal pump action of the flange portion having a larger diameter than the other end of the shroud, and the same effect as the configuration of claim 1 is obtained. .

Further, in this configuration in which the flange portion is made larger in diameter than the other end portion of the shroud, it is not necessary to adjust the gap between the shroud and the housing or the gap between the flange portion and the concave portion, and the cost can be reduced accordingly.

The invention according to claim 4 is the invention according to claims 1 to 3.
4. The centrifugal fluid machine according to claim 1, wherein the housing includes a first housing member and a second housing member fixed to each other.
The housing member and the recess through which the flange portion of the shroud penetrates is formed by a recess provided in the first housing member and a plane of the second housing member. 3 has the same effect as any of the above.

In addition, the housing is divided into two parts, and the recess into which the flange penetrates is formed by the recess of the first housing member and the flat surface of the second housing member, for example, to adjust the sealing performance. Therefore, when the flange portion is changed to a different outer diameter, it is possible to cope with low cost only by changing the first housing member.

[0026]

1 and 2 show a first embodiment of the present invention.
An embodiment will be described. This embodiment is defined in claims 1, 2, and 4.
It has the following features. Hereinafter, the left and right directions are the left and right directions in FIG. 1, and members without reference numerals and the like are not shown.

FIG. 1 shows a mechanical supercharger 1, which comprises an input pulley 3, a planetary gear type speed increasing mechanism 5, and a centrifugal air compressor 7 (first embodiment). Centrifugal fluid machine).

The air compressor 7 is used, for example, as a compressor for a refrigerator that compresses a refrigerant in a refrigeration cycle, and is driven by an engine or a motor.

The input pulley 3 comprises a pulley body 9 and a hub 11
The hub 11 is fixed to the input shaft 15 of the speed increasing mechanism 5 with a key 17 and a nut 19. The input pulley 3 is connected to a pulley on the crankshaft side via a belt, and is driven to rotate by the driving force of the engine.

The input shaft 15 is supported on a boss 25 of a casing 23 by a bearing 21. Input shaft 15
A seal 27 is disposed between the casing and the casing 23 to prevent oil leakage.

The speed-increasing mechanism 5 includes a flange 2 of the input shaft 15.
9, an internal gear 31, a plurality of pinion gears 33 arranged at regular intervals in the circumferential direction, and a sun gear 37 formed on an impeller shaft 35 of the air compressor 7.

The pinion gear 33 is supported on a pinion shaft 41 via a bearing 39. The pinion shaft 41 is supported by penetrating the flange member 43 of the casing 23, and is prevented from falling off by a ball 45 and a screw 47.

The flange member 43 is fitted into the inner periphery of the casing 23, and an O-ring 48 is disposed between the flange members 43 to prevent oil from leaking to the outside.

A sun gear 37 is provided on the impeller shaft 35.
From the right side, a ring 49, a ring 51, a spacer 53,
The bush 55 and the impeller 57 are mounted and fixed with the nut 59.

The speed increasing mechanism 5 speeds up the driving force of the engine input from the input pulley 3 to the internal gear 31 through the pinion gear 33 via the sun gear 37, and drives the impeller shaft 35 (impeller 57) to rotate at high speed.

The compressor housing 61 of the air compressor 7 has a swirl chamber member 65 (first housing member) having a swirl chamber 63 (swirl type fluid flow path) and a suction port member 69 (inflow port) having a suction port 67 (inflow port). (A second housing member) with a bolt 71.

The compressor housing 61 and the casing 23 are fixed to each other by fixing the connecting member 75 engaged with the peripheral groove 73 of the casing 23 to the spiral chamber member 65 with bolts 77 with the flange member 43 interposed therebetween.

The air compressor 7 sucks the intake air from the inlet 67 by the rotation of the impeller 57, and the sucked intake moves to the swirling chamber 63 by the centrifugal force of the impeller 57 and is pressurized. The engine is supercharged by being discharged from the outlet 78 (outlet).

The speed increasing mechanism 5 and the air compressor 7 are separated by a partition 79 of the flange member 43. A labyrinth ring 81 having a saw-tooth groove is fixed to the partition 79 by bolts 83, and the impeller 5
7 form a labyrinth seal 85. The labyrinth seal 85 reduces the air leakage of the air compressor 7 by the pressure reducing action.

The flange member 43 includes a bearing holder 8.
7 is fixed by a retaining ring 89 and a stepped portion 91. The bearing holder 87 includes a cylindrical portion 93 and a conical convex portion 95, and the convex portion 95 penetrates through a conical concave portion 97 formed on the input shaft 15 through a small gap.

A sun gear 37 is provided on the impeller shaft 35.
, A sliding bearing 99 is arranged on the left side, and a sliding bearing 101 is arranged on the outer periphery of the spacer 53. These sliding bearings 99 and 101 are each provided with a bearing holder 87.
The impeller shaft 35 is supported between the inner periphery of the convex portion 95 and the inner periphery of the cylindrical portion 93.

A thrust washer 103 is mounted on the bearing holder 87 from the outside in the radial direction. The thrust washer 103 engages with a groove 105 formed between the rings 49 and 51, and the thrust washer 103 of the impeller shaft 35. Receiving power.

An oil plug 107 attached to the casing 23 from an external oil pump and the nozzle 1 are provided between the sliding bearings 99 and 101 and the bearing holder 87.
The pressurized oil is supplied via the oil passages 09 and the flange member 43 and the bearing holder 87 to form an oil film damper.

Each of the sliding bearings 99 and 101 is floatingly supported by the oil film damper, and supports the impeller shaft 35 while absorbing vibration. This pressurized oil is also supplied to the groove 105 and the thrust washer 1
03 is lubricated, and further supplied to the seal 27 via the oil passage 113 to lubricate the seal.

As shown in FIG. 1, the impeller 57 is configured by connecting a hub 115 (base) fixed to the impeller shaft 35 and a shroud 117 by a number of blades 119.

Right end of shroud 117 (one side end)
Has a flange member 121 fixed in the centrifugal direction,
The flange member 12 is provided in the compressor housing 61.
A recess 123 into which 1 penetrates is provided.

The recess 123 is formed by a recess 125 provided in the spiral chamber member 65 and a plane 127 of the suction port member 69.

The outer diameter D1 of the left end (the other end) of the shroud 117 is larger than the outer diameter D2 of the flange member 121. A gap A between the shroud 117 and the compressor housing 61 is formed by the flange member 121 and the recess 123.
Is wider than the gap B.

By making the gap B smaller than the gap A, a labyrinth sealing effect is obtained in the gap B, and leakage (bypass) of intake air is prevented between the shroud 117 and the compressor housing 61 (gap A). You. Thus, the mechanical supercharger 1 is configured.

In the mechanical supercharger 1, as described above, the leakage of the intake air is prevented by the labyrinth sealing effect of the gap B narrower than the gap A, and the sealing performance and efficiency of the air compressor 7 are improved.

Further, since the gap B formed by the flange member 121 has a large area, its labyrinth sealing effect is large, and leakage of intake air is effectively prevented.

Unlike the conventional example in which the labyrinth seal is arranged in the centrifugal direction, the gap B is formed substantially perpendicular to the centrifugal direction by providing the flange member 121 in the centrifugal direction.

Therefore, even if the impeller 57 expands due to the centrifugal force, or if the impeller 57 expands due to the low pressure generated in the gap A due to the relative rotation between the impeller 57 and the compressor housing 61, the width of the gap B becomes large. Not affected.

In this manner, contact between the impeller 57 and the compressor housing 61 due to the expansion of the impeller 57, heat generation and wear due to the contact, leakage of intake air, and the like are prevented, and the sealing performance and efficiency of the air compressor 7 are kept high.

Further, the flange member 12 is attached to the shroud 117.
By fixing 1, the strength of the shroud 117 is improved, so that the durability of the impeller 57 against high-speed rotation is increased, and the expansion of the impeller 57 due to centrifugal force, the contact with the compressor housing 61, the deterioration of sealing performance, and the like. Is prevented.

The flange member 121 is connected to the shroud 11
7, the effect of preventing the deformation of the shroud 117 by the flange member 121 is greatest.

The compressor housing 61 is divided into a swirl chamber member 65 and a suction port member 69, and a recess 123 into which the flange member 121 of the shroud 117 penetrates.
Is formed by the concave portion 125 of the spiral chamber member 65 and the flat surface 127 of the suction port member 69, for example, to adjust the labyrinth sealing effect of the gap B by the flange member 1
Even in the case of changing the outer diameter 21 to one having a different outer diameter, it is possible to cope with low cost only by changing the spiral chamber member 65.

Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment has the features of claims 1, 3, and 4.

In the description of FIG. 3 and the second embodiment, members having the same functions as those of the first embodiment are given the same reference numerals and are quoted, and redundant description of these same members is omitted.

FIG. 3 shows a mechanical supercharger 129,
The mechanical supercharger 129 includes an input pulley 3, a planetary gear type speed increasing mechanism 131, and a centrifugal air compressor 1.
33 (centrifugal fluid machine of the second embodiment).

The speed increasing mechanism 131 is formed on an internal gear 135 formed on the flange portion 29 of the input shaft 15, a plurality of pinion gears 137 arranged at regular intervals in the circumferential direction, and an impeller shaft 35 of the air compressor 133. Provided with a sun gear 139. Each of these gears is constituted by a helical gear.

The input shaft 15 is supported by a boss 25 of the casing 23 via a double-row angular ball bearing 141 in order to receive a meshing thrust force of the helical gear generated in the internal gear 135.

The pinion gear 137 is supported on a pinion shaft 145 via double-row angular ball bearings 143 to receive the meshing thrust force. The pinion shaft 145 is the casing 2
3 is supported through the flange member 43 of the
7 and screws 149.

The mechanical supercharger 129 is arranged downstream of the throttle valve. A space 151 is provided between the bearing holder 87, the flange member 43, and the impeller 57.
Are formed. The downstream side of the throttle valve communicates with this space 151 via a bypass passage 153 and a control valve. When a negative pressure is generated on the right side of the impeller 57 due to the opening degree of the throttle valve, the space 151 is opened by the control valve to the atmosphere side. And is always kept at positive pressure.

A flange member 155 is fixed in the centrifugal direction to the right end (one end side: inflow end) of the shroud 117 of the impeller 57. The compressor housing 61 is provided with a recess 157 through which the flange member 155 penetrates through an appropriate gap.
7 is formed by a concave portion 159 provided in the spiral chamber member 65 and a plane 127 of the suction port member 69.

A seal 161 is formed by the flange member 155 and the concave portion 159, and the flange member 155
Is the outer diameter D1 of the other end of the shroud 117.
It is larger.

As described above, the outer diameter D3 of the flange member 155
Is larger than the outer diameter D1 of the shroud 117, so that when the impeller 57 rotates, the flange member 155
Accelerates the intake air of the concave portion 157 in the centrifugal direction to perform a centrifugal pump action. Due to such a centrifugal pump action of the seal 161, the shroud 117 and the compressor housing 61 are formed.
The leakage of the intake air is prevented between the first and second states. Thus, the mechanical supercharger 129 is configured.

In the mechanical supercharger 129, as described above,
Since the leakage of the intake air is prevented by the centrifugal pumping action of the seal of the seal 161 formed by the flange member 155 and the concave portion 157, unlike the conventional example in which the labyrinth seal is disposed in the centrifugal direction, the impeller 57 is centrifugally driven. The seal 161 is not affected even if it expands, or if the impeller 57 expands due to the low pressure generated in these gaps due to the relative rotation between the impeller 57 and the compressor housing 61.

Therefore, contact between the impeller 57 and the compressor housing 61 due to expansion of the impeller 57, heat generation and wear due to the contact, leakage of intake air, and the like are prevented, and the sealing performance and efficiency of the air compressor 133 are kept high.

Further, the flange member 15 is attached to the shroud 117.
5, the strength of the shroud 117 is improved, so that the durability of the impeller 57 against high-speed rotation is increased, and the impeller 57 expands due to centrifugal force, comes into contact with the compressor housing 61, and the sealing performance is reduced. Is prevented.

The flange member 155 is connected to the shroud 11
7, the effect of preventing deformation of the shroud 117 by the flange member 155 is the greatest.

In this configuration in which the outer diameter D3 of the flange member 155 is larger than the outer diameter D1 of the shroud 117,
There is no need to adjust the gap between the shroud 117 and the compressor housing 61 or the gap between the flange member 155 and the concave portion 157, and the cost can be reduced accordingly.

In addition to this, the compressor housing 6
1 is divided into two parts, a spiral chamber member 65 and a suction port member 69, and a concave part 157 into which the flange member 155 of the shroud 117 penetrates is formed by the concave part 159 of the spiral chamber member 65 and the plane 127 of the suction port member 69. Accordingly, for example, even when the flange member 155 is changed to one having a different outer diameter in order to adjust the sealing property of the seal 161, it is possible to cope with low cost only by changing the spiral chamber member 65.

The centrifugal fluid machine according to the present invention is used not only as a compressor for compressing a fluid by applying a rotational force to an impeller as in each embodiment but also for expanding a pressurized fluid. You may use as an expander which takes out a rotational force.

[0075]

According to the centrifugal fluid machine of the first aspect, the leakage of the fluid is prevented by the centrifugal pump action of the seal formed by penetrating the flange provided on the shroud of the impeller into the recess of the housing. Unlike the conventional example, even if the impeller expands, it contacts the housing,
Heat generation and wear due to contact, fluid leakage, and the like are prevented, and the sealing performance and efficiency of the centrifugal fluid machine are kept high.

Further, since sufficient sealing properties can be obtained as described above, the housing can be integrally formed, unlike the conventional example, so that the structure is simplified, the number of parts is reduced, and the cost is reduced. .

Further, since the strength of the shroud is improved by the flange portion, the durability of the impeller against high-speed rotation is increased, and expansion of the impeller due to centrifugal force, contact with the housing, deterioration of sealing performance, and the like are further reduced. .

According to the second aspect of the present invention, the gap B between the flange portion and the concave portion is made smaller than the gap A between the shroud and the housing.
By the labyrinth seal effect obtained in (1), leakage of the fluid is prevented, and the gap B formed by the flange portion has a large area, so that a large labyrinth seal effect and a leak prevention effect can be obtained.

Further, since the flange portion is formed in the centrifugal direction, unlike the conventional example, the gap B is formed substantially perpendicular to the centrifugal direction. It is. Thus, the same effect as that of the first aspect is obtained.

According to the third aspect of the present invention, leakage of fluid between the shroud and the housing is prevented by the centrifugal pump action of the flange portion having a larger diameter than the other end of the shroud.
An effect equivalent to that of the configuration of claim 1 is obtained.

Further, in this configuration in which the flange portion has a larger diameter than the other end portion of the shroud, it is not necessary to adjust the gap between the shroud and the housing and the gap between the flange portion and the concave portion, and the cost can be reduced accordingly.

The invention according to claim 4 is the invention according to claims 1 to 3.
In addition to obtaining the same effect as any one of the above, the recess into which the flange penetrates is formed by the recess of the first housing member and the plane of the second housing member. Even when the outer diameter is changed, the cost can be reduced simply by changing the first housing member.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrow A in FIG. 1;

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view showing a main part of a conventional example.

[Explanation of symbols]

 7, 129 Air compressor (centrifugal fluid machine) 57 Impeller 61 Compressor housing 63 Spiral chamber (swirl fluid path) 65 Spiral chamber member (first housing member) 67 Suction port (inlet) 69 Suction port member (second) Housing member) 78 Discharge port (outflow port) 115 Impeller hub (base) 117 Impeller shroud 119 Impeller blade 121, 155 Flange member (Flange part) 123, 157 Concave part into which flange member penetrates 125, 159 Vortex chamber member Concave portion 127 Plane of inlet member 161 Seal A Clearance between shroud and compressor housing B Clearance between flange member and concave portion (labyrinth seal) D1 Outer diameter of other end of shroud D2 Outer diameter of flange member 121 D3 Flange member 155 Outer diameter of

Claims (4)

[Claims] 1. A housing in which a fluid inlet and an outlet are provided at both ends of a spiral fluid flow path whose cross-sectional area perpendicular to the moving direction of the fluid changes toward one side, and a rotation inside the housing. An impeller, which is freely arranged and connects a shroud and a base facing the housing with a number of blades, a flange provided on the shroud, and a recess on the housing into which the flange penetrates through a gap, A centrifugal fluid machine comprising a seal between a shroud and a housing for preventing fluid leakage. 2. The invention according to claim 1, wherein the flange is provided in a centrifugal direction near one end of the shroud, and the outer diameter of the other end of the shroud is equal to the outer diameter of the flange. Larger, clearance A between shroud and housing
Is wider than a gap B between the flange portion and the concave portion. 3. The invention according to claim 1, wherein the flange portion is provided near one end of the shroud, and the outer diameter of the other end of the shroud is smaller than the outer diameter of the flange portion. A centrifugal fluid machine. 4. The invention according to claim 1, wherein the housing comprises a first housing member and a second housing member fixed to each other, and a flange portion of the shroud. The recess into which
A centrifugal fluid machine formed by a concave portion provided in a first housing member and a plane of a second housing member.