阅读说明：本技术 离心压缩机 (Centrifugal compressor ) 是由 藤田豊 岩切健一郎 于 2021-05-18 设计创作，主要内容包括：本发明提供一种与以往相比,能更高效且有效地、节约地实现小流量区域中的效率提高和宽量程化的离心压缩机。本发明具备：叶轮(17)；压缩机罩(20),该压缩机罩至少包括形成有用于向叶轮(17)输送气体的进气流路的入口管部(24)；可动构件(31),该可动构件以沿叶轮(17)的轴线O1方向可移动的方式配置于压缩机罩(20)的内部；以及移动机构,该移动机构构成为使可动构件(31)沿叶轮(17)的轴线O1方向,该移动机构构成为通过使可动构件(31)沿轴线O1方向移动,使可动构件(31)与压缩机罩(20)的内壁面彼此接触,压缩机罩(20)或可动构件(31)的至少一方的彼此接触的接触部分(35a、35b)由可磨密封材料或高弹塑性材料构成。(The invention provides a centrifugal compressor which can more efficiently, effectively and economically realize the efficiency improvement and the wide range in a small flow area compared with the prior art. The present invention is provided with: an impeller (17); a compressor cover (20) that includes at least an inlet pipe portion (24) in which an intake flow path for conveying gas to the impeller (17) is formed; a movable member (31) which is disposed inside the compressor cover (20) so as to be movable in the direction of the axis O1 of the impeller (17); and a moving mechanism configured to move the movable member (31) in the direction of the axis O1 of the impeller (17), the moving mechanism being configured to move the movable member (31) in the direction of the axis O1 to bring the movable member (31) and the inner wall surface of the compressor cover (20) into contact with each other, and contact portions (35a, 35b) of at least one of the compressor cover (20) and the movable member (31) that are in contact with each other being composed of a grindable sealing material or an elastoplastic material.)

1. A centrifugal compressor is provided with:

an impeller;

a compressor cover including at least an inlet pipe portion formed with an intake flow path for sending gas to the impeller;

a movable member disposed inside the compressor cover so as to be movable in an axial direction of the impeller; and

a moving mechanism configured to move the movable member in an axial direction of the impeller, the moving mechanism being configured to move the movable member in the axial direction to bring the movable member and an inner wall surface of the compressor cover into contact with each other,

at least one of the compressor cover and the movable member has a contact portion that contacts each other and is made of an abradable seal material or an elastomeric material.

2. The centrifugal compressor according to claim 1,

the abradable seal material is any one of a resin-based material, a carbon-based material, and a metal-based material.

3. The centrifugal compressor according to claim 1,

the high elastic plastic material is as follows: the contact portion has elasticity in a state where the contact portion is formed, and the yield stress that transitions to plastic deformation in the relation of stress-strain is small as compared with a compressor cover main body portion formed of a main raw material of the compressor cover.

4. The centrifugal compressor according to claim 3,

the high elastic plastic material is as follows: in a state where the contact portion is formed, a linear elastic coefficient is larger than that of the compressor cover main body portion.

5. The centrifugal compressor according to claim 2 or 3,

the high elastic plastic material is any one of resin material, carbon material and metal material.

6. The centrifugal compressor according to any one of claims 1 to 4,

the movable member is configured by an annular member disposed in the intake passage so as to be movable toward a downstream side in the axial direction,

the annular member is configured to contact an inner wall surface of the inlet pipe portion on an upstream side of a leading edge of an impeller blade of the impeller.

7. The centrifugal compressor of claim 6,

in the inlet pipe portion, an inlet pipe portion side seal layer formed in a contact portion of the inlet pipe portion with the annular member is composed of the abradable seal material.

8. The centrifugal compressor according to claim 7,

the compressor cover further includes: a shroud face including a face opposed to a tip end of a vane of the impeller,

the inlet pipe portion-side seal layer is formed over at least a part of the mat surface from the contact portion.

9. The centrifugal compressor of claim 6,

the compressor cover includes a compressor cover main body portion and the inlet pipe portion detachably attached to the compressor cover main body portion,

with respect to the inlet tube portion, the entire inlet tube portion is composed of the high elastic plastic material.

10. The centrifugal compressor according to any one of claims 6 to 9,

in the annular member, an annular member-side seal layer formed in a contact portion of the annular member with the inner wall surface of the inlet pipe portion is composed of the abradable seal material.

11. The centrifugal compressor according to any one of claims 6 to 9,

as for the annular member, the entire portion of the annular member is composed of the high elastic plastic material.

Technical Field

The present disclosure relates to a centrifugal compressor.

Background

Conventionally, as a technique for improving the output of an engine such as an automobile engine, a turbocharger (supercharger) is often used which compresses intake air taken in from the engine and supplies the intake air having a high density and containing a large amount of oxygen to the engine.

The turbocharger includes, for example: a rotating shaft; a centrifugal compressor (compressor) provided on one end side of the rotating shaft; and a turbine provided on the other end side of the rotating shaft, the turbocharger being configured to: the energy of the exhaust gas delivered from the engine rotates an impeller (turbine wheel) of the turbine, and at the same time, the rotating shaft, and hence the impeller (compressor wheel) of the centrifugal compressor, rotates around the axis to compress intake air, which is supplied to the engine.

Here, for example, in an automobile engine, as an element showing the commercial performance thereof, a response to an accelerator operation at a low speed (for example, a portion S of fig. 4), that is, an acceleration performance, a low-speed torque expression performance, and the like are important.

Therefore, the following is required for the centrifugal compressor of the turbocharger: the compression efficiency in the small flow rate region of the intake air is improved to improve the intake efficiency of the compressed air to the engine, or the wide range of the performance/operating range R indicated by the relationship between the flow rate of the intake air (CW flow rate) and the pressure ratio (CW pressure ratio) is increased, and in particular, the movable range on the surge line (surge line) side (reference sign S portion) in the small flow rate region of the intake air is expanded.

In contrast, there is a centrifugal compressor in which air is taken in from an intake port together with rotation of an impeller of the centrifugal compressor and a throttle mechanism is provided in an intake flow path for taking in air toward the impeller of the centrifugal compressor. In this centrifugal compressor, the throttle mechanism controls the intake air flow path area to be reduced at the time of small flow rate intake air. This makes it possible to suppress a recirculation flow of intake air, i.e., a reverse flow of intake air, which is likely to occur on the tip end side (shroud side) of the rotor blades of the impeller during small-flow intake air, and to improve efficiency and widen the range in a small-flow region.

Some of such throttle mechanisms are arranged coaxially with the intake air flow path and fixedly provided with an annular ring member. In this throttle mechanism, the fixed annular member functions as a guard wall, and can suppress a reverse flow at the time of a small flow rate intake.

However, in the case of the large/medium flow intake, there is a possibility that the efficiency on the choke flow rate (maximum flow rate) and the large flow rate side is reduced.

On the other hand, there is a throttle mechanism configured to include: a movable member (e.g., an annular member) disposed coaxially with the intake passage of the centrifugal compressor and supported to be movable forward and backward in the axial direction between the intake side of the intake passage and the impeller side; and a moving mechanism for moving the movable member back and forth in the front-rear direction along the axis (see, for example, patent document 1 (patent document 2, patent document 3)).

The throttle mechanism is configured to, for example: the movable member is moved forward and arranged on the front side to increase the flow area of the intake flow path during large/medium flow intake, and is retracted to the rear side so as to approach the impeller side of the centrifugal compressor by the moving mechanism during small flow intake, and is brought into contact with and brought into close contact with the inner wall surface of the compressor cover forming the intake flow path.

This prevents a reduction in efficiency on the choke flow rate side and the large flow rate side during the large/medium flow rate intake. Further, when the small flow rate of intake air is taken in, the movable member is brought into contact with and brought into close contact with the inner wall surface of the compressor cover, whereby the movable member is disposed so as to shield the inner wall surface side of the intake air flow passage, and the flow path area of the intake air flow passage can be made small while suppressing the backflow of intake air that is likely to occur at the tip end side (shroud side) of the rotor blade of the impeller at the time of the small flow rate of intake air. Thus, the effective flow path area of the intake flow path can be adjusted according to the flow rate of intake air, and efficiency improvement and wide-ranging in a small flow rate region can be achieved.

Documents of the prior art

Patent document

Patent document 1: specification of U.S. Pat. No. 9777640

Patent document 2: international publication No. 2019/004228

Patent document 3: japanese patent laid-open publication No. 2019-152121

Disclosure of Invention

Problems to be solved by the invention

However, in the above-described conventional throttle mechanism including the movable member, if the movable member retreated to the impeller side of the centrifugal compressor is not brought into complete close surface contact with the inner wall surface of the compressor cover over the entire circumference at the time of a small flow rate, a recirculation flow (backflow) of intake air leaks through a gap between the movable member and the inner wall surface of the compressor cover, and a desired recirculation flow suppression effect cannot be obtained, which may lead to an increase in leakage loss. That is, it is sometimes difficult to appropriately achieve efficiency improvement and wide-ranging in a small flow rate region.

In the conventional throttle mechanism described above, in order to bring the movable member into complete close contact with the inner wall surface of the compressor housing at a low flow rate, very high precision machining accuracy and assembly accuracy are required in machining the movable member or the inner wall surface of the compressor housing, the moving mechanism, and the like, and assembling the movable member or the moving mechanism. That is, if the movable member, the compressor cover, or the like is not machined or manufactured with very high machining accuracy or assembly accuracy, it may be difficult to improve efficiency and increase the range in a small flow rate region. Thus, the manufacture of the throttle mechanism, the centrifugal compressor, and the turbocharger requires a large amount of labor, time, effort, and cost.

In view of the above circumstances, an object of the present disclosure is to provide a centrifugal compressor capable of more efficiently and effectively realizing an improvement in efficiency and a wider range in a small flow rate region than in the related art.

Technical scheme

A centrifugal compressor according to one aspect of the present disclosure includes: an impeller; a compressor cover including at least an inlet pipe portion in which an intake flow path for feeding gas to the impeller is formed; a movable member disposed inside the compressor cover so as to be movable in an axial direction of the impeller; and a moving mechanism configured to move the movable member in an axial direction of the impeller, wherein the moving mechanism is configured to move the movable member in the axial direction to bring the movable member and an inner wall surface of the compressor cover into contact with each other, and a portion of at least one of the compressor cover and the movable member in contact with each other is made of a abradable seal material or an elastoplastic material.

Effects of the invention

According to the centrifugal compressor of one aspect of the present disclosure, it is possible to provide a centrifugal compressor which can improve efficiency and increase a range more efficiently, effectively, and economically than in the conventional art in a small flow rate region, and which is excellent in workability, and further, reliability, and durability.

Drawings

Fig. 1 shows an example of a turbocharger including a centrifugal compressor according to an embodiment of the present disclosure.

Fig. 2 is a partial sectional view showing an example of a centrifugal compressor according to an embodiment of the present disclosure.

Fig. 3A is a partial sectional view showing an example of a movable member of a centrifugal compressor according to an embodiment of the present disclosure.

Fig. 3B is a partial sectional view showing an example of a movable member of a centrifugal compressor according to an embodiment of the present disclosure.

Fig. 3C is a partial sectional view showing an example of a movable member of a centrifugal compressor according to an embodiment of the present disclosure.

Fig. 3D is a partial sectional view showing an example of a movable member of a centrifugal compressor according to an embodiment of the present disclosure.

Fig. 4 is a diagram showing an example of the performance of the centrifugal compressor according to the embodiment of the present disclosure, and is a diagram showing a relationship between the flow rate of intake air and the pressure ratio.

Fig. 5 is a partial sectional view showing a modified example of the centrifugal compressor according to the embodiment of the present disclosure.

Detailed Description

Hereinafter, a centrifugal compressor according to an embodiment will be described with reference to fig. 1 to 5.

Here, in the present embodiment, the centrifugal compressor of the present disclosure is described as a centrifugal compressor provided in a turbocharger, but the centrifugal compressor of the present disclosure may be, for example, an electric centrifugal compressor, and the gas to be compressed is not necessarily limited to air. That is, the centrifugal compressor of the present disclosure may be constituted by a centrifugal compressor alone, or may be constituted by combining a mechanism or a device other than a turbine, as long as the centrifugal compressor can compress and convey a gas. Further, the use and the like thereof are not necessarily limited.

(turbocharger)

For example, as shown in fig. 1, the turbocharger 1 of the present embodiment is configured such that: the energy of the exhaust gas G delivered from an engine such as an automobile engine rotates the impeller (turbine) 3 of the turbine 2 about the axis (rotation axis) O1, and at the same time, rotates the rotary shaft 4 coaxially coupled to the impeller 3, and further rotates the impeller (compressor wheel) 17 of the centrifugal compressor (compressor) 5 coaxially coupled to the rotary shaft 4, and the impeller 17 sucks in and compresses air (intake air, gas) a, and supplies compressed air (compressed gas) a' to the engine.

(turbine)

The turbine 2 includes: an impeller 3 coaxially connected to the other end of the rotary shaft 4;

and a turbine housing (turbine housing) 7 that houses the impeller 3.

The impeller 3 includes: a turbine hub 8 having a substantially truncated cone shape and coaxially coupled to the rotary shaft 4; and turbine buckets 9 extending from the outer peripheral surface of the turbine hub 8 radially outward of the center of the axis O1.

An exhaust gas flow path R5 formed by a scroll flow path R3 and a nozzle flow path R4 is provided radially outside the center of the axis O1 of the impeller 3 of the turbine 2, the scroll flow path R3 is provided around the impeller 3 and transports the exhaust gas G discharged from the engine to the impeller 3, and the nozzle flow path R4 is provided with an exhaust gas flow rate control device such as a nozzle vane 10.

Further, on the rear side (the exhaust gas G discharge port 11 side) in the direction of the axis O1 of the impeller 3: the discharge passage R6 (exhaust passage R5) is coaxial with the impeller 3, and receives and discharges the exhaust gas G discharged from the outlet of the turbine rotor blade 9 of the impeller 3 to the outside. The discharge flow path R6 is formed by the exhaust diffusion chamber 12.

In the turbocharger 1 of the present embodiment, the scroll flow path R3, the nozzle flow path R4, and the discharge flow path R6 (exhaust diffusion chamber 12) are formed by the turbine cover 7 that houses the impeller 3.

(centrifugal compressor: compressor)

The centrifugal compressor 5 of the present embodiment includes: an impeller (compressor wheel) 17 of the centrifugal compressor 5 coaxially coupled to one end side of the rotary shaft 4 rotatably supported by the bearing stands 15 and 16; and a compressor housing 20 accommodating the impeller 17.

The impeller 17 of the centrifugal compressor 5 includes: a compressor hub 21 having a substantially truncated cone shape and coaxially coupled to the rotary shaft 4; and compressor blades (impeller blades) 22 extending radially outward from the outer circumferential surface of the compressor hub 21 toward the center of the axis O1.

The impeller 17 is provided with, on the front side (the side of the air inlet 23 of the air a) in the direction of the axis O1: the intake air flow path R1 is for sucking the air a together with the rotation of the impeller 17 and sending it to the impeller 17.

Further, radially outside the center of the axis O1 of the impeller 17, there are provided: the compressed air flow path (compressed gas flow path) R2 has a volute R2 for receiving the compressed air a' discharged from the impeller 17 and sending the air to the engine.

In the turbocharger 1 of the present embodiment, the portion of the compressor cover 20 where the intake air a is provided and the intake air flow path R1 for supplying the intake air a to the impeller 17 is defined as the inlet pipe portion (intake portion) 24, and the portion where the compressed air flow path R2 is formed is defined as the compressor cover main body portion 25. In the present embodiment, the inlet pipe portion 24 and the compressor housing main body portion 25 are formed using, for example, a metal such as aluminum (a main material of the compressor housing 20). As will be described later, the inlet pipe portion 24 may be formed separately, or the inlet pipe portion 24 and the compressor housing main body portion 25 may be formed of different materials.

In the turbocharger 1 of the present embodiment configured as described above, the exhaust gas G discharged from the engine is supplied from the radially outer side of the impeller 3 of the turbine 2 through the scroll flow path R3 and the nozzle flow path R4 of the turbine 2, and the impeller 3 is rotationally driven by the energy of the exhaust gas G. The rotation of the impeller 3 rotationally drives the rotary shaft 4 and the impeller 17 of the centrifugal compressor 5.

The air a sucked from the suction port 23 of the inlet pipe portion 24 by the rotation of the impeller 17 flows through the intake flow path R1, is supplied to the impeller 17 and compressed, and the compressed air a' is supplied to the engine through the compressed air flow path R2. The exhaust gas G obtained by rotationally driving the impeller 3 of the turbine 2 flows through the exhaust passage R6 of the exhaust diffusion chamber 12, recovers the pressure thereof, and is discharged to the outside.

On the other hand, the centrifugal compressor 5 (turbocharger 1) of the present embodiment includes: the flow area adjusting section 30 adjusts the effective flow area of the intake air flow path R1 that sucks air a by the rotation of the impeller 17 and supplies the air a to the inlet pipe section 24 of the impeller 17, and adjusts the flow rate, pressure, and flow velocity of the air (intake air) a at the inlet of the impeller 17.

As shown in fig. 1 and 2, the flow path area adjustment unit 30 of the centrifugal compressor 5 according to the present embodiment includes: a movable member 31 disposed inside the inlet pipe portion 24 that is inside the compressor cover 20 and provided to be movable forward and backward in the direction of the axis O1 of the impeller 17; and a moving mechanism (not shown) for moving the movable member 31 in the direction of the axis O1.

The movable member 31 of the present embodiment is an annular member formed in an annular shape, and is provided in the intake passage R1 inside the inlet pipe portion 24 so as to be coaxially arranged with the axis O1 between the intake passage R1 and the inlet pipe portion 24.

When the movable member 31 is moved rearward in the direction of the axis O1 by the moving mechanism, it is brought into contact with the inner wall surface 24a of the inlet pipe portion 24 on the upstream side of the leading edge of the rotor blade 22 of the impeller 17.

Here, the shape of the movable member 31 is not particularly limited. For example, as shown in fig. 2 and 3A to 3D, the sectional shape of the movable member 31, the shape of the contact portion 35(35a, 35b) of the inner wall surface 24a of the compressor cover 20 and the movable member 31 that contacts each other, the orientation with respect to the axis O1, and the like may be determined as appropriate.

For example, the inner and outer peripheral surfaces (the entire inner peripheral surface and the entire outer peripheral surface) of the movable member 31 may be inclined with respect to the axis O1, or the leading edge side and the trailing edge side of the movable member 31 may have different shapes (may have asymmetric shapes) with respect to the center of the movable member 31 in the thickness direction along the axis O1.

The invention invented by the inventor of the present application, and the "application number: PCT/JP2019/11539 "," application No.: the "annular portion" shown in PCT/JP2019/11544 "can be preferably used as an example of the movable member 31.

The moving mechanism includes, for example: a support column (not shown) for supporting the movable member (annular member) 31, and an actuator (not shown).

As shown in fig. 2, the flow area adjustment unit 30 is configured such that the movable member (annular member) 31 is movable in the direction of the axis O1 between a first position P1 in the direction of the axis O1 of the intake air flow path R1 and a second position P2 on the upstream side of the first position P1 in the direction of the axis O1 by driving the actuator of the moving mechanism to move the strut back and forth in the direction of the axis O1. Further, when the movable member 31 moves to the first position P1, the flow area adjustment portion 30 is configured such that the movable member 31 abuts against the inner wall surface 24a of the compressor cover 20 that forms the intake flow path R1.

In the present embodiment, in order to suppress as much as possible an increase in pressure loss of intake air due to the movable member 31 being disposed in the intake passage R1, the inner wall surface 24a of the compressor cover 20 forming the inlet pipe portion 24 is formed to include: the inclined surface (tapered surface) 24b is inclined such that the inner diameter of the inlet pipe portion 24 (the diameter of the intake air flow path R1) increases toward the front side in the direction of the axis O1, that is, toward the upstream side in the flow direction of the intake air.

In the present embodiment, the inclined surface 24b is formed such that the diameter of the intake air flow path R1 gradually increases from the inlet side of the impeller 17 on the rear end side of the inlet pipe portion 24 toward the inlet port 23 side.

When the movable member 31 is retracted to the first position P1 by the moving mechanism, the outer peripheral surface 31a of the movable member 31 on the rear end side abuts against the inclined surface 24b, and the effective flow area of the intake flow passage R1 is reduced in the flow area adjusting portion 30.

More specifically, the movable member (annular member) 31 of the present embodiment is formed such that the contact portion 35a of the outer peripheral surface 31a faces the inclined surface 24b side, and when the movable member 31 is located at the second position P2, the contact portion 35a of the movable member 31 is separated from the inclined surface 24b, and the distance between the contact portion 35a of the movable member 31 and the inclined surface 24b becomes smaller as the movable member 31 moves from the second position P2 to the downstream side in the axis O1 direction.

When the movable member 31 retreats to the first position P1, the contact portion 35a of the outer peripheral surface 31a abuts against the inclined surface 24b, and blocks an outer peripheral portion corresponding to the tip end portion of the impeller vane 22 (the radially outer end portion of the vane 22) in the intake flow path R1. At this time, the movable member 31 and the tip end portion of the impeller blade 22 at least partially overlap as viewed in the direction of the axis O1.

Accordingly, when the movable member 31 is disposed at the first position P1, the outer peripheral portion corresponding to the tip end portion of the impeller blade 22 is closed by the movable member 31, and the effective flow passage area of the intake flow passage R1 is reduced.

When the flow path area is reduced by the retreat of the movable member 31 in this manner, the maximum efficiency is reduced, but the surge flow rate is reduced and the efficiency near the surge point is improved.

That is, the movable member 31 is located at the first position P1 at an operating point on the small flow rate side (an operating point near the surge point), and the movable member 31 is located at the second position P2 at an operating point on the large flow rate side (for example, during stop motion) at which the flow rate is greater than the operating point on the small flow rate side, so that the effective flow passage area can be adjusted in size according to the flow rate of intake air. As a result, as shown in fig. 4, the efficiency of the operating point on the small flow rate side can be improved and the movable range/operating range of the centrifugal compressor can be expanded. That is, efficiency improvement and wide-ranging in a small flow rate region can be achieved.

Incidentally, the outer peripheral surface 31a of the movable member 31 of the present embodiment is formed in a convex arc shape in which the leading edge and the trailing edge are smoothly connected, so that the flow can be suppressed from peeling off from the outer peripheral surface 31a of the movable member 31 when the movable member 31 is located at the second position P2, and the efficiency of the centrifugal compressor 5 can be suppressed from being lowered.

Here, in the flow passage area adjustment portion (throttle mechanism) 30 provided with the movable member 31, if the movable member 31 retreated toward the impeller 17 side does not completely and closely contact the inner wall surface 24a (contact portions 35a, 35b) of the compressor cover 20 over the entire circumference at the time of a small flow rate, a recirculation flow (reverse flow) of the intake air leaks through a gap between the movable member 31 and the inner wall surface 24a of the compressor cover 20. Then, if this leakage occurs, the desired effect of suppressing the recirculation flow cannot be obtained, resulting in an increase in leakage loss, and as a result, improvement in efficiency and widening of the range in the small flow rate region cannot be appropriately achieved.

In order to bring the movable member 31 into close contact with the inner wall surface 24a of the compressor cover 20 at a low flow rate, very high precision machining accuracy and assembly accuracy are required for machining the movable member 31 or the inner wall surface 24a of the compressor cover 20, the moving mechanism, and the like, and for assembling and assembling the movable member 31 or the moving mechanism. That is, if the movable member 31, the compressor cover 20, or the like is not machined or manufactured with very high machining accuracy or assembly accuracy, it is not possible to improve efficiency and increase the range in a small flow rate region. Thus, the flow path area adjusting unit (throttle mechanism) 30, the centrifugal compressor 5, and the turbocharger 1 require a large amount of labor, time, effort, and cost for their manufacture.

In the turbocharger 1 of an automobile engine or the like, for example, the flow rate of intake air is varied at an unexpected frequency by an accelerator pedal or the like. Therefore, the movable member 31 repeats the forward and backward movement and the sliding movement in the direction of the axis O1 a very large number of times to such an extent that they cannot be assumed.

When the movable member 31 moves forward and backward (slides) an unexpected number of times, the movable member 31 contacts and presses the inner wall surface 24a of the compressor cover 20 each time the intake air flow rate becomes small. That is, the movable member 31 collides with the inner wall surface 24a of the compressor cover 20. Since this collision is repeated an unexpected number of times, there is a possibility that abrasion will occur at the contact portion 35a of the outer peripheral surface 31a of the movable member 31 and the contact portion 35b of the inner wall surface 24a of the compressor cover 20 made of aluminum or the like with which the movable member 31 is in contact. Then, if this abrasion occurs, a gap is generated to induce leakage of the recirculation flow, and it is not possible to appropriately achieve improvement in efficiency and widening of the range in the small flow rate region.

Further, the movable member 31 may be damaged by repeatedly colliding with the movable member 31 by an unexpected number of times.

Further, each time the movable member 31 collides with the inner wall surface 24a of the compressor cover 20, there is a fear that abnormal noise such as a click may be generated.

In contrast, in the centrifugal compressor 5 (and the turbocharger 1) of the present embodiment, at least one of the portions (35a, 35b) of the movable member 31 and the compressor cover 20 that contact each other is formed using a grindable sealing material or an elastoplastic material.

Here, the "abradable seal material" in the present disclosure is a material having a characteristic of being easily cut (machinability), and is a known material that is often used when it is necessary to fill up a gap between components rotating at high speed at high temperature and to perform a gap control close to zero.

Examples of the "abradable seal material" include resin-based materials (e.g., single-resin-material-based materials, composite resin-material-based materials using a plurality of resins, composite resin-material-based materials mixed with a filler such as carbon), carbon-based materials, metal-based materials (e.g., nickel-based, aluminum-based, copper-based, and other soft light metal-based materials), and the like.

As an example of a conventional use of the "abradable seal material" (see fig. 1), a centrifugal compressor (compressor) 5 and a turbine 2 are laminated by thermal spraying on inner wall surfaces of covers (casings) 7 and 20, and interposed between tip portions of moving blades 9 and 22 of respective impellers 3 and 17 and inner wall surfaces of the covers 7 and 20. In this case, when each impeller 3, 17 rotates, the seal layer of the "abradable seal material" having machinability is cut by the tip end portions of the movable blades 9, 22, and the clearance between the tip end portions of the movable blades 9, 22 and the inner wall surface of the covers 7, 20 is optimized to be zero. By controlling the gap with the "abradable seal material" to fill the gap, the efficiency of the centrifugal compressor 5 and the turbine 2 can be improved.

On the other hand, the "high elastic plastic material" in the present disclosure means the following materials (members): the yield stress that transitions to plastic deformation in the relationship of stress-strain is small compared to a metal material such as aluminum that has been conventionally used as a material for forming the compressor cover 20 (the compressor cover main body portion 25 and the like) in many cases. Further, the "high elastic plastic material" in the present disclosure is preferably the following materials (members): the linear elastic modulus is larger than that of a metal material such as aluminum forming the compressor cover main body portion 25 of the conventional compressor cover 20.

Examples of such "high elastic plastic material" include resin-based materials (e.g., single resin material-based materials, composite resin material-based materials using a plurality of resins, composite resin material-based materials mixed with a filler such as carbon, etc.), carbon-based materials, metal-based materials (e.g., soft light metal-based materials such as nickel-based materials, aluminum-based materials, copper-based materials, etc.), and the like.

(effect of centrifugal compressor of the present disclosure)

Further, in the centrifugal compressor 5 (and the turbocharger 1) of the present embodiment, as shown in fig. 2, the contact portions 35a, 35b where at least one of the movable member 31 and the compressor cover 20 are in contact with each other are formed using such abradable seal materials (32, 34) or high elastic plastic materials.

Therefore, the movable member 31 retreated toward the impeller 17 can be easily brought into close contact with the inner wall surface 24a of the compressor cover 20 over the entire circumference in a small flow rate intake as compared with the conventional case. That is, since the contact portions 35a and 35b of at least one of the movable member 31 and the compressor cover 20 are formed using the abradable seal material (32, 34) or the high elastic plastic material, the movable member 31 abuts against the inner wall surface 24a of the compressor cover 20 by the moving mechanism, and the contact portions 35a and 35b formed using the abradable seal material (32, 34) or the high elastic plastic material are deformed (elastically deformed, etc.), whereby the contact portions 35a and 35b of the movable member 31 and the compressor cover 20 can be easily brought into close contact with each other over the entire circumference.

At this time, since the contact portions 35a and 35b of at least one of the movable member 31 and the compressor cover 20 are formed using the abradable seal material (32 and 34) having a cutting property or the high elastic plastic material having an elastic plastic property, the movable member 31 can be moved backward by the moving mechanism at the time of small flow rate intake, and the movable member 31 can be brought into contact with the compressor cover 20 so as to exert a large pressing force without considering abrasion. This makes it possible to more easily bring the contact portions 35a and 35b of the movable member 31 and the compressor cover 20 into complete close contact over the entire circumference.

Further, even when the relative positions of the contact portions 35a, 35b of the movable member 31 and the inner wall surface 24a of the compressor cover 20 are slightly displaced, since the contact portions 35a, 35b are formed using the abradable seal material (32, 34), the high elastic plastic material, the movable member 31 is pressed against the inner wall surface 24a of the compressor cover 20, and the abradable seal material (32, 34), the high elastic plastic material absorbs the displacement (deflection) of the relative positions, and the contact portions 35a, 35b of the movable member 31 and the compressor cover 20 can be easily brought into close contact with each other.

Thus, as in the conventional art, it is not necessary to require extremely high machining accuracy and assembly accuracy in machining the moving mechanism and the like, assembling the movable member 31 and the moving mechanism, and the like, and the number of manufacturing steps can be increased, and the cost can be reduced.

Even when the movable member 31 moves back and forth (slides) by an unexpected number of times, the contact portions 35a and 35b between the movable member 31 and the inner wall surface 24a of the compressor cover 20 are formed using an abradable seal material (32, 34) or a high elastic plastic material, and therefore, abrasion does not occur (is not likely to occur) on the movable member 31 and the inner wall surface 24a of the compressor cover 20 due to collision of the movable member 31. At this time, when the abradable seal material (32, 34) or the high elastic plastic material of the contact portions 35a, 35b is deformed, the movable member 31 can be brought into close contact with the contact portions 35a, 35b of the compressor cover 20 in accordance with the deformation.

Further, even if the movable member 31 repeatedly collides an unexpected number of times, the occurrence of damage to the movable member 31 and the like can be appropriately suppressed.

Thus, even when contact and collision of the movable member 31 with the inner wall surface 24a of the compressor cover 20 are repeated an unexpected number of times, leakage of the recirculation flow is not induced by the occurrence of a gap, and efficiency improvement and wide-ranging in a small flow rate region can be appropriately achieved.

Further, by forming the contact portions 35a, 35b between the movable member 31 and the inner wall surface 24a of the compressor cover 20 with an abradable seal material (32, 34) such as resin or soft light metal, or a high elastic plastic material, it is possible to prevent the generation of abnormal noise in the form of a click whenever the movable member 31 contacts the inner wall surface 24a of the compressor cover 20.

Therefore, according to the centrifugal compressor 5 of the present embodiment, by constituting the contact portions 35a, 35b of at least one of the movable member 31 and the compressor cover 20, which are in contact with each other, with the abradable seal material (32, 34) or the high elastic plastic material, it is possible to effectively suppress the leakage of the recirculation flow (reverse flow) of the intake air through the gap between the movable member 31 and the inner wall surface 24a of the compressor cover 20. Thus, efficiency improvement and wide-ranging in a small flow rate region can be achieved more efficiently, effectively, and economically than in the conventional art.

In the centrifugal compressor 5 of the present embodiment, the movable member 31 is formed of an annular member disposed in the intake air flow passage R1 so as to be movable toward the downstream side in the direction of the axis O1, and the annular member of the movable member 31 is configured to contact the inner wall surface 24a of the inlet pipe portion 24 on the upstream side of the front edge of the impeller blade 22 of the impeller 17.

With such a configuration, the occurrence of a recirculation flow (backflow) of intake air can be suppressed more reliably by the movable member 31.

Here, in the centrifugal compressor 5 of the present embodiment, the following configurations (a) to (e) will be described as examples of the configuration that can suitably exhibit the above-described operational effects and the use of the abradable seal material and the high elastic plastic material separately.

(a) As shown in fig. 2, the inlet pipe portion-side seal layer 32, which is coated with an abradable seal material or the like to form a film, is provided at least at a contact portion 35b of the inner wall surface 24a of the compressor cover 20 (a contact portion 35b of the inlet pipe portion 24 with the movable member (annular member) 31).

(b) As shown in fig. 2, an annular member-side seal layer 34 formed by coating an abradable seal material or the like is provided at least at a contact portion 35a of the movable member (annular member) 31 with the inner wall surface 24a of the inlet pipe portion 24.

As in the above (a) and (b), when the inlet pipe-side seal layer 32 and the annular member-side seal layer 34 made of an abradable seal material are provided at least at one of the contact portion 35b of the inner wall surface 24a of the compressor cover 20 and the contact portion 35a of the movable member 31, the inlet pipe-side seal layer 32 and the annular member-side seal layer 34 can be formed by applying the abradable seal material to the contact portions 35a and 35b and the like. That is, the operational effects of the centrifugal compressor of the present embodiment described above can be easily obtained.

(c) Further, as shown in fig. 2, when the inlet pipe portion side seal layer 32 is formed using an abradable seal material, the seal layer 33 may be formed using an abradable seal material over at least a part of the shroud surface 36 including the surface facing the tip end of the impeller blade 22 from the contact portion 35b of the inner wall surface 24a of the compressor cover 20.

In other words, the inlet pipe side seal layer 32 is formed so as to extend to the contact portion 35b of the inner wall surface 24a of the compressor cover 20, the seal layer 33 being composed of an abradable seal material for optimizing the gap between the tip end portions of the rotor blades 22 of the impeller 17 of the centrifugal compressor 5 and the inner wall surface 24a of the compressor cover 20 to zero.

In this case, in order to improve the efficiency of the centrifugal compressor 5, when the shroud surface 36 facing the tip end portions of the rotor blades 22 is laminated by applying an abradable seal material or the like, the contact portion 35b of the inner wall surface 24a of the compressor cover 20 that is in contact with the movable member 31 may be laminated by applying an abradable seal material or the like.

This makes it easier to form the inlet pipe side seal layer 32 to prevent the occurrence of a recirculation flow, and improves efficiency together with filling up the gap between the shroud surface 36 and the rotor blade 22 with the seal layer 33 of a abradable seal material. That is, the centrifugal compressor 5 having excellent efficiency performance while maintaining the manufacturing man-hour quota can be easily realized.

(d) Further, as shown in fig. 5, the compressor cover 20 is configured by detachably attaching the inlet pipe portion 24 to the compressor cover main body portion 25, and the inlet pipe portion 24 is entirely formed of a high elastic plastic material (or the inlet pipe portion side seal layer 32 may be formed by coating an abradable seal material or the like on the contact portion 35b of the movable member 31 of the detachable inlet pipe portion 24).

In this case, it is preferable that the fitting portion 40 (fitting convex portion 40a, fitting concave portion 40b) is provided on the rear end portion side of the inlet pipe portion 24 and the front end portion side of the compressor housing main body portion 25, respectively, and the rear end portion side of the inlet pipe portion 24 and the front end portion side of the compressor housing main body portion 25 are configured to be fitted to each other and to be positioned and held at a predetermined relative position. Preferably, the inlet pipe portion 24 is provided with a flange portion and a plurality of screw insertion holes penetrating the flange portion on the rear end portion side of the inlet pipe portion 24, and a plurality of female screw holes are provided at predetermined positions on the front end portion side of the compressor housing main body portion 25, so that the inlet pipe portion 24 can be screwed and firmly fixed to the compressor housing main body portion 25.

With such a configuration, the centrifugal compressor 5 of the present embodiment can achieve the operational effects thereof, and the inlet pipe portion 24 can be exchanged, thereby improving operability and maintainability.

(e) Further, the entirety of the annular member of the movable member 31 is made of a high elastic plastic material.

In this case, the centrifugal compressor 5 of the present embodiment can exhibit the operational effect, and the movable member 31 can be easily exchanged, so that the operability and maintainability can be improved.

(f) The above-described structures (a) to (e) may be optionally combined as appropriate.

In any of the above configurations (a) to (e), the above (operational effect of the centrifugal compressor of the present disclosure) can be obtained.

While one embodiment of the centrifugal compressor of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and modifications may be made as appropriate within a range not departing from the gist thereof.

For example, in the present embodiment, the movable member 31 is an annular member and is provided in the intake air flow path R1 so as to be movable in the direction of the axis O1, thereby adjusting the effective flow path area.

In contrast, in the centrifugal compressor of the present disclosure, the movable member does not necessarily have to be an annular member, and the configuration of the moving mechanism that moves the movable member in the axial direction is not particularly limited as in the present embodiment.

In the centrifugal compressor of the present disclosure, the movable member 31 does not have to be provided in the intake flow path R1 formed as in the present embodiment, and may be provided in the interior of the compressor cover so as to improve efficiency and widen the range in a small flow rate region more efficiently and effectively than in the related art, and the shape and arrangement (installation position) thereof are not particularly limited.

For example, a bypass flow path communicating with the intake flow path R1 may be provided in the compressor cover 20, the effective flow path area of the bypass flow path may be adjusted by the forward and backward movement of the movable member 31 in the direction of the axis O1, and the inner wall surface of the compressor cover 20 and the contact portions 35a and 35b of the movable member 31 forming the bypass flow path may be formed of an abradable seal material or an elastoplastic material.

Finally, the contents described in the above embodiments are grasped as follows, for example.

(1) A centrifugal compressor (centrifugal compressor, compressor 5) according to one aspect includes: an impeller (impeller 17); a compressor cover (compressor cover 20) including at least an inlet pipe portion (inlet pipe portion 24) in which an intake flow path (intake flow path R1) for sending gas (air a) to the impeller is formed; a movable member (movable member, annular member 31) disposed inside the compressor cover so as to be movable in the axial direction of the impeller (direction of axis O1); and a moving mechanism configured to move the movable member in the axial direction of the impeller, the moving mechanism being configured to move the movable member in the axial direction to bring the movable member and an inner wall surface (inner wall surface 24a) of the compressor cover into contact with each other, contact portions (contact portions 35a, 35b) of at least one of the compressor cover or the movable member, which contact each other, being made of a grindable sealing material or a high elastic plastic material.

According to the centrifugal compressor described in the above (1), since the portion where the movable member and at least one of the compressor cover are in contact with each other is formed using the abradable seal material or the high elastic plastic material, the movable member retreating to the compressor wheel side can be easily brought into completely close contact with the inner wall surface of the compressor cover at the time of small flow rate intake as compared with the conventional art.

That is, the movable member is brought into contact with the inner wall surface of the compressor cover by the moving mechanism, and the contact portion formed using the abradable seal material or the high elastic plastic material is deformed (elastically deformed or the like), so that the contact portion between the movable member and the compressor cover can be brought into close surface contact with each other easily.

In this case, since the contact portion between the movable member and the compressor cover is formed using an abradable seal material having machinability or an elastoplastic high-elastic plastic material, the movable member can be moved backward by the moving mechanism at the time of small-flow intake air, and the movable member can be brought into contact with the compressor cover so that a larger pressing force acts than in the conventional case. This makes it possible to more easily bring the contact portion between the movable member and the compressor cover into close surface contact.

Further, even in the case where the relative position of the contact portion between the movable member and the inner wall surface of the compressor cover is slightly shifted, since the contact portion between the movable member and the inner wall surface of the compressor cover is formed using an abradable seal material or a high elastic plastic material, it is possible to absorb the shift (deflection) of the relative position between the movable member and the inner wall surface of the compressor cover by pressing the movable member against the inner wall surface of the compressor cover, and easily bring the contact portion between the movable member and the compressor cover into close surface contact.

Therefore, at a low flow rate, it is not necessary to require extremely high machining accuracy and assembly accuracy in machining of the moving mechanism and the like, assembly and assembly of the moving member or the moving mechanism, and the like as in the conventional art in order to bring the moving member into complete close contact with the inner wall surface of the compressor cover, and it is possible to improve the manufacturing man-hour quota and reduce the cost.

Therefore, according to the centrifugal compressor of the above (1), by constituting the portion of at least one of the movable member and the compressor cover, which contacts each other, with a grindable sealing material or an elastoplastic material, it is possible to effectively suppress the leakage of the recirculation flow (reverse flow) of the intake air through the gap between the movable member and the inner wall surface of the compressor cover. Thus, efficiency improvement and wide-ranging in a small flow rate region can be achieved more efficiently, effectively, and economically than in the conventional art.

(2) In a centrifugal compressor according to another aspect, in the centrifugal compressor according to the above (1), the abradable seal material is any one of a resin-based material, a carbon-based material, and a metal-based material.

The centrifugal compressor according to the above (2), preferably, the operational effect of the above (1) can be obtained.

(3) In another centrifugal compressor, in the centrifugal compressor according to the above (1), the high elastic plastic material is as follows: in the state where the contact portion is formed, it has elasticity, and the yield stress that transitions to plastic deformation in the relation of stress-strain is small as compared with the compressor cover main body portion (compressor cover main body portion 25) formed of the main raw material of the compressor cover.

The centrifugal compressor according to the above (3), preferably, the operational effect of the above (1) can be obtained.

(4) In another centrifugal compressor, in the centrifugal compressor according to the above (3), the high elastic plastic material is as follows: in the state where the contact portion is formed, the linear elastic coefficient is larger than that of the compressor cover main body portion.

The centrifugal compressor according to the above (4), wherein the operational effect of the above (1) can be preferably obtained.

(5) In a centrifugal compressor according to another aspect, in the centrifugal compressor according to the above (2) or (3), the high elastic plastic material is any one of a resin-based material, a carbon-based material, and a metal-based material.

The centrifugal compressor according to the above (5), wherein the operational effects of the above (1) can be preferably obtained.

(6) In another centrifugal compressor according to any one of the above (1) to (4), the movable member is configured by an annular member disposed in the intake passage so as to be movable toward the downstream side in the axial direction, and the annular member is configured to contact an inner wall surface of the inlet pipe portion on the upstream side of a leading edge of an impeller blade (impeller blade, movable blade 22) of the impeller.

According to the centrifugal compressor described in the above (6), since the portion where at least one of the movable member and the compressor cover is in contact with each other is formed using the abradable seal material or the high elastic plastic material, the annular member of the movable member retreating to the compressor wheel side can be easily brought into complete close contact with the inner wall surface of the compressor cover over the entire circumference at the time of small-flow intake.

This effectively suppresses leakage of the recirculation flow of intake air through the gap between the annular member of the movable member and the inner wall surface of the compressor cover, and can further efficiently and effectively achieve efficiency improvement and wide-range widening in a small flow rate region than in the past.

(7) In the centrifugal compressor according to the other aspect, in the centrifugal compressor according to the above (6), the inlet pipe portion is formed with an inlet pipe portion side seal layer (inlet pipe portion side seal layer 32) formed at a contact portion of the inlet pipe portion with the annular member, which is made of an abradable seal material.

According to the centrifugal compressor described in the above (7), the inlet pipe portion side seal layer is formed by coating an abradable seal material or the like on the contact portion of the inlet pipe portion, and the operational effects described in the above (1), (6) and the like can be obtained.

In other words, the inlet pipe portion side seal layer is formed by coating only the contact portion of the inlet pipe portion with an abradable seal material or the like, and the effects described in (1), (6) and the like above can be obtained.

(8) In the centrifugal compressor according to another aspect, in the centrifugal compressor according to the above (7), the compressor cover further includes: the shroud face (shroud face 36) includes a face facing the tip of the impeller blade, and the inlet pipe portion-side seal layer is formed so as to extend over at least a part of the shroud face from the contact portion.

According to the centrifugal compressor described in the above (8), the inlet pipe portion side seal layer is formed such that the seal layer made of an abradable seal material for optimizing the gap between the tips of the impeller blades and the inner wall surface of the compressor cover to zero extends to the contact portion of the inner wall surface of the compressor cover.

In this case, in order to improve the efficiency of the compressor, an abradable seal material or the like may be applied to the shroud surface facing the tips of the impeller blades to laminate the shroud surface, and an abradable seal material or the like may be applied to the contact portion of the inner wall surface of the compressor cover that contacts the movable member to laminate the shroud surface.

This makes it easier to form the inlet pipe side seal layer to prevent the occurrence of a recirculation flow, and makes it possible to obtain an effect of improving efficiency together with filling up the gap between the shroud surface and the rotor blade with the seal layer of the abradable seal material. That is, a centrifugal compressor having excellent efficiency performance while maintaining the manufacturing man-hour quota can be easily realized.

(9) In another centrifugal compressor of the above (6), the compressor cover includes a compressor cover main body portion (compressor cover main body portion 25) and an inlet pipe portion detachably attached to the compressor cover main body portion, and the inlet pipe portion is formed of a highly elastic plastic material as a whole.

According to the centrifugal compressor described in the above (9), the inlet pipe portion can be separately produced using the high elastic plastic material, and only the inlet pipe portion is attached to the compressor housing main body portion, so that the operational effects described in the above (1), (6), and the like can be easily obtained.

In addition, the inlet pipe portion made of the elastic plastic material as a whole can be removed from the compressor housing main body portion and replaced. This can greatly improve the operability, maintainability, etc. of the centrifugal compressor (inlet pipe portion).

(10) In a centrifugal compressor according to another aspect of the present invention, in the centrifugal compressor according to any one of the above (6) to (9), the annular member is configured such that the annular member-side seal layer (the annular member-side seal layer 34) formed in a contact portion of the annular member with the inner wall surface of the inlet pipe portion is formed of an abradable seal material.

According to the centrifugal compressor described in the above (10), the effect described in the above (1), (6) to (9) and the like can be obtained by applying an abradable seal material or the like to the contact portion of the annular member as the movable member to form the annular member side seal layer.

In other words, the annular member side seal layer is formed by coating an abradable seal material or the like only on the contact portion of the annular member as the movable member, and the above-described effects (1), (6) to (9) and the like can be obtained.

(11) In a centrifugal compressor according to another aspect, in the centrifugal compressor according to any one of the above (6) to (9), the annular member is formed of an elastic plastic material as a whole.

According to the centrifugal compressor described in the above (11), the entire annular member as the movable member can be produced solely using the high elastic plastic material, and the operational effects described in the above (1), (6) to (9) and the like can be easily obtained.

In addition, since the entire annular member as the movable member is made of a high elastic plastic material, ease of manufacturing and maintainability such as replacement can be improved.

Description of the reference numerals

1 turbo charger

2 turbine

3 turbine wheel (turbine)

4 rotating shaft

5 centrifugal compressor (compressor)

7 turbine cover (turbine casing)

17 impeller of centrifugal compressor (compressor wheel)

20 compressor cover

22 compressor rotor blade (impeller rotor blade and rotor blade)

24 inlet pipe part (suction part)

24a inner wall surface (inner peripheral surface)

25 compressor cover body part

30 flow path area adjusting part

31 Movable Member (Ring-shaped Member)

32 inlet pipe side seal layer (abradable seal material)

33 sealing layer

34 side sealing layer of annular component (abradable seal material)

35a contact part

35b contact part

36 cover of shield