JP2019127898A - Centrifugal compressor - Google Patents

Abstract

To provide a centrifugal compressor which can suppress the leakage of cooling water in a cooling water path to an oil space in a bearing housing.SOLUTION: A centrifugal compressor 101 comprises: a seal member 51 which is arranged between a seal plate 40 and a bearing housing 30, and in a position inside the seal plate 40 in a radial direction rather than a cooling water path 14; a seal member 52 arranged between the seal plate 40 and the bearing housing 30, and in a position inside the seal plate 40 in the radial direction rather than the seal member 51; and a communication path 60 having a first end part 61 and a second end part 62 communicating with the first end part 61. The first end part 61 is arranged in a position between the seal plate 40 and the bearing housing 30, and between the seal member 51 and he seal member 52, and the second end part 62 is arranged in a space having pressure different from the pressure of the cooling water flowing in the cooling water path 14.SELECTED DRAWING: Figure 1

Description

 The present invention relates to a centrifugal compressor.

In a centrifugal compressor, two impellers of a turbine impeller and a compressor impeller are integrally formed via a shaft, and the engine is charged by rotation of the turbine impeller and the compressor impeller. In recent years, the demand for centrifugal compressors has increased. In order to introduce more air by EGR (Exhaust Gas Recirculation), the centrifugal compressor is required to be boosted higher.

When the supercharging pressure required for a centrifugal compressor increases, the pressure ratio before and after the compressor impeller (compressor outlet pressure / compressor inlet pressure) increases, and the compressor outlet (diffuser path) temperature reaches, for example, nearly 200 ° C. To rise. Further, the air introduced into the centrifugal compressor contains blowby gas that has been refluxed from the crank chamber to the upstream of the centrifugal compressor. When the compressed air discharged from the compressor reaches a high temperature, the mist-like oil contained in the blowby gas adheres to the diffuser wall surface of the compressor housing as a deposit as the oil component evaporates from the oil. As a measure for suppressing the occurrence of such deposits, there is known a technique of providing a cooling water passage at a position facing the back surface of the compressor impeller (Japanese Patent Laid-Open No. 2009-243299).

JP 2009-243299 A

In the centrifugal compressor disclosed in JP2009-243299A (Patent Document 1), the bearing housing and the water channel component are joined to each other, and a cooling water channel is formed between the bearing housing and the water channel component. Has been. An O-ring is provided at a joint portion (position around the cooling water channel) between the bearing housing and the water channel component.

A space to which oil is supplied is provided on the radially inner side of the cooling water channel (inside the bearing housing). The O-ring is a joint between the bearing housing and the water channel component, and is provided at a position radially inward of the cooling water channel and a position radially outward. The O-ring provided on the radially inner side of the cooling water channel prevents the cooling water in the cooling water channel from leaking into the oil space.

When the O-ring provided radially inward of the cooling water channel can not exhibit a sufficient waterproof function due to deterioration or damage, the cooling water in the cooling water channel may leak into the oil space. The oil supplied to the oil space in the bearing housing is not limited to the shaft of the centrifugal compressor, and may also be used to lubricate the engine system. If the cooling water in the cooling water channel is mixed in the oil, the performance and malfunction of the engine system may be caused.

An object of the present invention is to provide a centrifugal compressor having a structure capable of suppressing the leakage of cooling water in a cooling water passage into an oil space in a bearing housing.

A centrifugal compressor according to the present invention has a shaft and an oil space to which oil is supplied, and a bearing housing rotatably supporting the shaft, and is attached to the shaft to rotate gas radially outward by rotation. An impeller for feeding the gas, a compressor housing having a suction passage for sucking the gas, and an annular shape provided between the bearing housing and the compressor housing and surrounding the impeller. A diffuser passage between the housing and the compressor housing, a cooling water passage for cooling the diffuser passage between the bearing housing and the oil passage located radially inward from the cooling water passage. Between the sealing plate and the bearing plate and the bearing housing A first seal member provided at a position radially inward of the seal plate with respect to the cooling water passage, for blocking communication from the cooling water passage to the oil space, and between the seal plate and the bearing housing A second seal member provided at a position radially inward of the seal plate with respect to the first seal member and blocking communication from the cooling water passage to the oil space; a first end portion; And a communication path having a second end communicating with one end, wherein the first end is between the seal plate and the bearing housing, and the first seal and the first housing. The second end portion is disposed at a position between the second seal member and the second seal member, and the second end portion is disposed in a space having a pressure different from that of the cooling water flowing in the cooling water passage.

In the centrifugal compressor, preferably, the space in which the second end is disposed has a pressure higher than the pressure of the cooling water flowing in the cooling water passage, and the high pressure causes
The pressure between the seal plate and the bearing housing and at a position radially inward of the first seal member is between the seal plate and the bearing housing and radially outward of the first seal member. It is higher than the pressure at the position.

Preferably, in the centrifugal compressor, the communication path is formed of a piping member having the first end and the second end, and the space in which the second end is disposed is the space of the diffuser passage. This is a scroll chamber provided downstream.

Preferably, in the centrifugal compressor, the communication path is provided to penetrate the seal plate, and the space in which the second end portion is disposed is the diffuser passage.

In the centrifugal compressor, preferably, the space in which the second end portion is disposed has a pressure lower than the pressure of the cooling water flowing in the cooling water passage, and the low pressure causes
The pressure between the seal plate and the bearing housing and at a position radially inward of the first seal member is between the seal plate and the bearing housing and radially outward of the first seal member. It is lower than the pressure at the position.

Preferably, in the centrifugal compressor, the communication path is provided to penetrate the bearing housing, and the space in which the second end portion is disposed is a space released to the atmosphere.

Preferably, in the centrifugal compressor, the communication path is formed of a piping member having the first end and the second end, and the space in which the second end is disposed is the suction passage. is there.

If the first seal member can no longer exhibit a sufficient waterproof function due to deterioration or damage,
The cooling water tends to flow from the position of the first seal member toward the position of the second seal member. The pressure difference causes the cooling water to be forced to exert a force such that it is pushed back toward the position of the first seal member, or flows to a different space without flowing toward the position of the second seal member. Such a force acts. Therefore, it is possible to suppress the cooling water in the cooling water passage from flowing into the oil space in the bearing housing.

1 is a cross-sectional view showing a centrifugal compressor 101 in Embodiment 1. FIG. 2 is an enlarged cross-sectional view of a part of a centrifugal compressor 101 according to Embodiment 1. FIG. FIG. 6 is a cross-sectional view showing a centrifugal compressor 102 in a second embodiment. FIG. 6 is a cross-sectional view showing a centrifugal compressor 103 in a third embodiment. FIG. 6 is a cross-sectional view showing a centrifugal compressor 104 in a fourth embodiment.

Embodiments will be described below with reference to the drawings. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated.

First Embodiment
(Centrifugal compressor 101)
FIG. 1 is a cross-sectional view showing centrifugal compressor 101 in the first embodiment. The centrifugal compressor 101 includes a compressor housing 10, a turbine housing 20, a bearing housing 30, a seal plate 40, an impeller 41, a turbine 42, a shaft 43, seal members 51, 52, 53, and a piping member 60.

The bearing housing 30 is provided between the compressor housing 10 and the turbine housing 20. The bearing housing 30 has an oil space 31 inside which oil is supplied. Oil used for engine system lubrication is also supplied into the oil space 31 and used for rotation of the shaft 43 and the like. The compressor housing 10 and the bearing housing 30 are joined to each other via a seal plate 40.

The shaft 43 is rotatably supported by the bearing housing 30 and the seal plate 40. A turbine 42 is attached to an end of the shaft 43 located on the turbine housing 20 side. An impeller 41 is attached to an end portion of the shaft 43 located on the compressor housing 10 side.

The turbine housing 20 has a discharge passage 21 and a scroll chamber 23. A valve mechanism 22 and a turbine 42 are disposed between the scroll chamber 23 and the discharge passage 21. Exhaust gas from the internal combustion engine is introduced through the scroll chamber 23. The exhaust gas is adjusted in flow velocity by the valve mechanism 22 and supplied to the turbine 42. Exhaust gas whose energy has been recovered by the turbine 42 is discharged through the discharge passage 21.

The compressor housing 10 has a suction passage 11, a diffuser passage 12 provided downstream of the suction passage 11, and a scroll chamber 13 provided downstream of the diffuser passage 12. The impeller 41 is located in the compressor housing 10 between the suction passage 11 and the diffuser passage 12, and the compressor housing 10 is arranged to surround the impeller 41.

Gas (air) to be supplied to the internal combustion engine is drawn into the compressor housing 10 through the suction passage 11. The gas is fed radially outward by the rotation of the impeller 41,
After being compressed by the diffuser passage 12, the scroll chamber 13 is reached. The compressed air passes through the scroll chamber 13 and is then supercharged to the internal combustion engine.

The seal plate 40 has an annular shape (substantially disk shape) extending in the radial direction, and is provided between the bearing housing 30 and the compressor housing 10. A surface of the seal plate 40 on the left side in FIG. 1 is joined to the compressor housing 10 by a bolt or the like (not shown). The seal plate 40 forms an annular diffuser passage 12 surrounding the impeller 41 with the compressor housing 10.

The surface of the seal plate 40 located on the right side in FIG. 1 is joined to the bearing housing 30. A cooling water passage 14 for cooling the diffuser passage 12 is formed between the seal plate 40 and the bearing housing 30. The seal plate 40 and the bearing housing 30 have a groove for forming the cooling water channel 14. The grooves provided in the seal plate 40 and the grooves provided in the bearing housing 30 are integrated so as to face each other, whereby the cooling water channel 14 is formed between these grooves.

(Seal members 51, 52, 53)
FIG. 2 is a cross-sectional view showing a part of the centrifugal compressor 101 in an enlarged manner. The oil space 31 of the bearing housing 30 radially inward of the joint interface formed between the seal plate 40 and the bearing housing 30 (in other words, radially inward away from the cooling water channel 14 of the seal plate 40). Is located. Between the seal plate 40 and the bearing housing 30, seal members 51, 52, 53 are provided which prevent the cooling water in the cooling water passage 14 from leaking out to the space other than the cooling water passage 14.

The seal member 51 (first seal member) is provided between the seal plate 40 and the bearing housing 30 at a position radially inward of the seal plate 40 relative to the cooling water channel 14.
Seal member 51 is formed of, for example, an O-ring, and blocks communication from cooling water passage 14 to oil space 31, and the cooling water in cooling water passage 14 forms seal plate 40 and bearing housing 30.
Is prevented from flowing inward in the radial direction along the bonding interface formed between the two.

The seal member 52 (second seal member) is provided between the seal plate 40 and the bearing housing 30 and at a position radially inward of the seal plate 40 than the seal member 51. Seal member 52 is formed of, for example, an O-ring, and oil space 31 from cooling channel
Further, the fluid communication with the cooling water passage 14 is blocked to prevent the cooling water in the cooling water passage 14 from flowing radially inward along the joint interface formed between the seal plate 40 and the bearing housing 30.

The seal member 53 is provided between the seal plate 40 and the bearing housing 30 and at a position radially outside the seal plate 40 with respect to the cooling water channel 14. The sealing member 53 is also
For example, it is formed of an O-ring to prevent the cooling water in the cooling water passage 14 from flowing radially outward along the joint interface formed between the seal plate 40 and the bearing housing 30.

(Piping member 60)
The piping member 60 is a hollow member that forms a communication path inside. The piping member 60 of the present embodiment is configured with nipples at both ends, and two nipples are connected by a hose-like member. The nipple on one side of the piping member 60 has a first end 61, and the nipple on the other side of the piping member 60 has a second end 62. The first end portion 61 and the second end portion 62 communicate with each other via a hose-like member.

The first end 61 is disposed between the seal plate 40 and the bearing housing 30 and at a position between the seal member 51 and the seal member 52. The nipple having the first end 61 is screwed and fixed to a screw hole or the like provided in the bearing housing 30. The second end 62 is disposed in a space having a pressure different from the pressure of the cooling water flowing in the cooling water passage 14.

In the present embodiment, the space in which the second end 62 is disposed has a pressure (for example, 300 kPa) higher than the pressure (for example, 200 kPa) of the cooling water flowing in the cooling water passage 14. Specifically, the space in which the second end 62 is disposed is the scroll chamber 13 provided downstream of the diffuser passage 12. The nipple having the second end 62 is screwed and fixed to a screw hole or the like provided in the compressor housing 10.

That is, the piping member 60 in the present embodiment is between the seal plate 40 and the bearing housing 30 and at a position between the seal member 51 and the seal member 52 (position of the first end 61). The scroll chamber 13 (position of the second end 62) provided downstream of the diffuser passage 12 is in communication.

Between the seal plate 40 and the bearing housing 30, the space (scroll chamber 13) in which the second end 62 is disposed has a pressure higher than the pressure of the cooling water flowing in the cooling water passage 14. The pressure at the radially inner position of the seal member 51 is higher than the pressure at the radially outer position of the seal member 51 between the seal plate 40 and the bearing housing 30. The pressure between the seal plate 40 and the bearing housing 30 at the radially inner position of the seal member 52 is a pressure equivalent to that of the oil space 31 and is, for example, a pressure that is negative with respect to the atmospheric pressure have.

(Function and effect)
As described at the beginning, when the seal members 51 and 52 provided on the inner side in the radial direction of the cooling water channel 14 can not exhibit a sufficient waterproof function due to deterioration or damage, the cooling water in the cooling water channel 14 is an oil space 31 There is a possibility of leaking. The oil supplied to the oil space 31 in the bearing housing 30 is not limited to the shaft 43 of the centrifugal compressor 101, and may be used also for lubricating the engine system. If the cooling water in the cooling water channel 14 is mixed into the oil, there is a possibility that the performance of the engine system is deteriorated or malfunctions.

In the present embodiment, the pressure between the seal plate 40 and the bearing housing 30 and at the radially inner position of the seal member 51 (pressure at the position between the seal member 51 and the seal member 52) The pressure between the plate 40 and the bearing housing 30 is higher than the pressure at the radially outer position of the seal member 51.

When the seal member 51 cannot exhibit a sufficient waterproof function due to deterioration or damage,
The cooling water tends to leak from the position of the seal member 51 toward the position of the seal member 52. Due to the pressure difference, a force that pushes back toward the position of the seal member 51 acts on the coolant that is about to leak. Therefore, even if the seal member 51 can not exhibit the waterproof function, the flow of the cooling water in the cooling water passage 14 to the oil space 31 in the bearing housing 30 can be suppressed.

Second Embodiment
FIG. 3 is a cross-sectional view showing centrifugal compressor 102 in the second embodiment. The centrifugal compressor 101 in the first embodiment and the centrifugal compressor 102 in the second embodiment are different in the following points.

The centrifugal compressor 102 of the present embodiment has a communication path 60A instead of the piping member 60 (see FIG. 2). The communication path 60 </ b> A is provided so as to penetrate the seal plate 40 from one surface of the seal plate 40 toward the other surface. The first end 61 and the second end 62 of the communication path 60A communicate with each other.

The first end 61 is disposed between the seal plate 40 and the bearing housing 30 and at a position between the seal member 51 and the seal member 52. As in the first embodiment,
The second end 62 is disposed in a space having a pressure different from the pressure of the cooling water flowing in the cooling water passage 14. In the present embodiment, the space in which the second end 62 is disposed is the diffuser passage 12.

That is, communication path 60A in the present embodiment is between seal plate 40 and bearing housing 30, and between seal member 51 and seal member 52 (position of first end 61), and The diffuser passage 12 (the position of the second end portion 62) is in communication.

Between the seal plate 40 and the bearing housing 30, the space (the diffuser passage 12) in which the second end 62 is disposed has a pressure higher than the pressure of the cooling water flowing in the cooling water passage 14. The pressure at the radially inner position of the seal member 51 is higher than the pressure at the radially outer position of the seal member 51 between the seal plate 40 and the bearing housing 30.

When the seal member 51 can not exhibit a sufficient waterproof function due to deterioration or damage,
The cooling water tends to leak from the position of the seal member 51 toward the position of the seal member 52. Due to the pressure difference, a force that pushes back toward the position of the seal member 51 acts on the coolant that is about to leak. Therefore, even if the seal member 51 can not exhibit the waterproof function, the flow of the cooling water in the cooling water passage 14 to the oil space 31 in the bearing housing 30 can be suppressed.

[Embodiment 3]
FIG. 4 is a cross-sectional view showing centrifugal compressor 103 in the third embodiment. The centrifugal compressor 101 according to the first embodiment is different from the centrifugal compressor 103 according to the third embodiment in the following points.

The centrifugal compressor 103 of the present embodiment has a communication path 60B instead of the piping member 60 (see FIG. 2). The communication path 60 </ b> B is provided so as to penetrate the bearing housing 30 from the end surface of the bearing housing 30 toward the side surface of the bearing housing 30. The first end 61 and the second end 62 of the communication path 60B communicate with each other.

The first end 61 is disposed between the seal plate 40 and the bearing housing 30 and at a position between the seal member 51 and the seal member 52. As in the first embodiment,
The second end 62 is disposed in a space having a pressure different from the pressure of the cooling water flowing in the cooling water passage 14. In the present embodiment, the space in which the second end portion 62 is disposed is a space released to the atmosphere. The space in which the second end 62 is disposed has a pressure (e.g., atmospheric pressure) lower than the pressure (e.g., 200 kPa) of the cooling water flowing in the cooling water passage 14.

That is, the communication path 60B in the present embodiment is between the seal plate 40 and the bearing housing 30 and at a position between the seal member 51 and the seal member 52 (position of the first end 61). The external space of the centrifugal compressor 103 (bearing housing 30) is in communication.

Since the space (the external space) in which the second end 62 is disposed has a pressure lower than the pressure of the cooling water flowing in the cooling water passage 14, the seal plate 40 and the bearing housing 3
The pressure on the radially inner position of the seal member 51 between 0 and is lower than the pressure on the radially outer position of the seal member 51 between the seal plate 40 and the bearing housing 30. .

When the seal member 51 cannot exhibit a sufficient waterproof function due to deterioration or damage,
The cooling water tends to leak from the position of the seal member 51 toward the position of the seal member 52. After reaching the first end 61 due to the pressure difference, the cooling water that has passed through the seal member 51 passes through the communication path 60B and is discharged from the second end 62 to the outside. Therefore,
Even in the case where the sealing member 51 can not exhibit the waterproof function, the flow of the cooling water in the cooling water passage 14 to the oil space 31 in the bearing housing 30 can be suppressed. Since the cooling water is discharged to the outside of the centrifugal compressor 103, it is easy to find that the seal member 51 is deteriorated or damaged.

[Embodiment 4]
FIG. 5 is a cross-sectional view showing centrifugal compressor 104 in the fourth embodiment. The centrifugal compressor 101 in the first embodiment and the centrifugal compressor 104 in the fourth embodiment are different in the following points.

The centrifugal compressor 104 of the present embodiment includes a piping member 60C instead of the piping member 60 (see FIG. 2). The piping member 60C is a hollow member that forms a communication path inside. The first end 61 of the piping member 60C is disposed between the seal plate 40 and the bearing housing 30 and at a position between the seal member 51 and the seal member 52. The nipple having the first end 61 is screwed and fixed to a screw hole or the like provided in the bearing housing 30.

The second end 62 is disposed in a space having a pressure different from the pressure of the cooling water flowing in the cooling water passage 14. In the present embodiment, the space in which the second end 62 is disposed has a pressure (for example, atmospheric pressure) lower than the pressure (for example, 200 kPa) of the cooling water flowing in the cooling water channel 14. Specifically, the space in which the second end portion 62 is disposed is the suction passage 11 provided upstream of the impeller 41. The nipple having the second end 62 is screwed and fixed to a screw hole or the like provided in the compressor housing 10.

That is, the piping member 60C in the present embodiment is between the seal plate 40 and the bearing housing 30, and at a position between the seal member 51 and the seal member 52 (position of the first end 61) The suction passage 11 provided upstream of the impeller 41 is communicated.

Between the seal plate 40 and the bearing housing 30, the space (intake passage 11) in which the second end 62 is disposed has a pressure lower than the pressure of the cooling water flowing in the cooling water passage 14. And the pressure at the radially inner position of the seal member 51
The pressure is lower than the pressure at a position on the radially outer side of the seal member 51 between the bearing housing 30 and the bearing housing 30.

When the seal member 51 cannot exhibit a sufficient waterproof function due to deterioration or damage,
Cooling water tends to leak from the position of the seal member 51 toward the position of the seal member 52. After reaching the first end 61 due to the pressure difference, the cooling water having passed through the sealing member 51 passes through the piping member 60C (hose portion) and is discharged from the second end 62 to the suction passage 11. The Therefore, even if the seal member 51 can not exhibit the waterproof function, the flow of the cooling water in the cooling water passage 14 to the oil space 31 in the bearing housing 30 can be suppressed.

Although the embodiments have been described above, the above disclosure is illustrative in all points and not restrictive. The technical scope of the present invention is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

DESCRIPTION OF SYMBOLS 10 Compressor housing, 11 Suction passage, 12 Diffuser passage, 13, 23 Scroll chamber, 14 Cooling water passage, 20 Turbine housing, 21 Discharge passage, 22
Valve mechanism, 30 bearing housing, 31 oil space, 40 seal plate, 41
Impeller, 42 turbine, 43 shaft, 51 seal member (first seal member),
52 seal member (second seal member), 53 seal member, 60, 60C piping member (communication path), 60A, 60B communication path, 61 first end, 62 second end, 101, 102, 103, 104 centrifugal Compressor.

Claims (7)

A shaft,
A bearing housing which has an oil space to which oil is supplied inside and rotatably supports the shaft;
An impeller attached to the shaft and delivering gas radially outward by rotation;
A compressor housing having a suction passage for suctioning the gas and disposed to surround the impeller;
An annular diffuser passage, which is provided between the bearing housing and the compressor housing and surrounds the impeller, is formed between the compressor housing, and a cooling water passage for cooling the diffuser passage is formed between the bearing housing and the bearing housing. A seal plate in which the oil space is located radially inside away from the cooling water channel;
A first seal member provided between the seal plate and the bearing housing, at a position radially inward of the seal plate with respect to the cooling water passage, for blocking communication from the cooling water passage to the oil space; ,
A second seal provided between the seal plate and the bearing housing, at a position radially inward of the seal plate with respect to the first seal member, for blocking communication from the cooling water channel to the oil space Members,
A communication path having a first end and a second end communicating with the first end;
The first end portion is disposed between the seal plate and the bearing housing and at a position between the first seal member and the second seal member.
The second end is disposed in a space having a pressure different from the pressure of the cooling water flowing in the cooling channel.
Centrifugal compressor. The space in which the second end portion is disposed has a pressure higher than the pressure of the cooling water flowing in the cooling water channel,
Due to the high pressure, a pressure at a position radially inward of the first seal member between the seal plate and the bearing housing is between the seal plate and the bearing housing and the first seal. It is higher than the pressure at the radially outer position of the member,
The centrifugal compressor according to claim 1. The communication path is formed from a piping member having the first end and the second end,
The space in which the second end portion is disposed is a scroll chamber provided downstream of the diffuser passage.
The centrifugal compressor according to claim 2. The communication path is provided to penetrate the seal plate,
The space in which the second end is disposed is the diffuser passage.
The centrifugal compressor according to claim 2. The space in which the second end portion is disposed has a pressure lower than the pressure of the cooling water flowing in the cooling water channel,
Due to the low pressure, the pressure at a position radially inward of the first seal member between the seal plate and the bearing housing is between the seal plate and the bearing housing and the first seal It is lower than the pressure at the radially outer position of the member,
The centrifugal compressor according to claim 1. The communication path is provided to penetrate the bearing housing,
The space in which the second end portion is disposed is a space released to the atmosphere.
The centrifugal compressor according to claim 5. The communication path is formed from a piping member having the first end and the second end,
The space in which the second end is disposed is the suction passage,
The centrifugal compressor according to claim 5.

Images