JP2018168742A - Recirculation flow passage structure, exhaust turbine supercharger, and engine - Google Patents

Abstract

To properly open and close a recirculation flow passage.SOLUTION: A recirculation flow passage structure comprises: a cylindrical inner tube 2 arranged in a casing 140 to surround the outer periphery on the front face 131a side of an impeller 131 in the circumferential direction, the casing receiving the impeller 131 in an internal space and partitioning a flow passage for a fluid; and a cover 3 which is formed in a cylindrical shape facing the front face of the inner tube 2 on the flow passage upstream side of the inner tube 2 and is arranged to be movable along the flow direction of the fluid by means of the difference between a first pressure F1 of the fluid acting on the front face facing the upstream side of the fluid passage and a second pressure F2 of the fluid acting on the back face. The inner tube 2 partitions a recirculation flow passage 4 between the downstream side and the upstream side of the fluid. The cover 3 moves to the upstream side to increase the flow rate of the fluid flowing in the recirculation flow passage 4 when the second pressure F2 is larger than the first pressure F1 and moves to the downstream side to reduce the flow rate of the fluid flowing in the recirculation flow passage 4 when the first pressure F1 is larger than the second pressure F2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a recirculation flow path structure for an exhaust turbine supercharger, an exhaust turbine supercharger, and an engine.

  In order to expand the operating range of the impeller of the exhaust turbine supercharger, it is known to arrange a recirculation flow path. A technique for opening and closing the recirculation flow path in accordance with the operating point is known in order to solve the problem that unnecessary recirculation occurs due to the arrangement of the recirculation flow path and the efficiency is lowered (for example, Patent Documents). 1). The technique described in Patent Document 1 opens and closes a recirculation flow path using an actuator.

JP 2012-041826 A

  For example, in a small exhaust turbine supercharger such as a turbocharger for automobiles, since the space is limited, it is difficult to apply an actuator to open and close the recirculation flow path. For example, in an inexpensive exhaust turbine supercharger such as a turbocharger for automobiles, it is difficult to apply an actuator because the cost increases when an actuator is used to open and close the recirculation flow path.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a recirculation flow path structure, an exhaust turbine supercharger, and an engine that can appropriately open and close the recirculation flow path. .

  The recirculation flow path structure of the present invention has a cylindrical shape in which an impeller is accommodated in an internal space, and the outer periphery on the front side of the impeller is disposed in a circumferential direction in a casing that divides a flow path of fluid. An inner cylinder and a first pressure and a rear surface of a fluid acting on a front surface facing the upstream side of the flow path, formed on the upstream side of the flow path from the inner cylinder and facing the front surface of the inner cylinder A cover that is movably disposed along a fluid flow direction by a difference from a second pressure of the acting fluid, and the inner cylinder is disposed between the downstream side and the upstream side of the flow path. When the second pressure is greater than the first pressure, the cover moves upstream, and increases the flow rate of the fluid flowing through the recirculation flow path. If the pressure is greater than the second pressure, the fluid moves downstream and reduces the flow rate of the fluid flowing through the recirculation flow path. Make, characterized in that.

  According to this configuration, the recirculation channel can be appropriately opened and closed by moving the cover.

  In the recirculation flow path structure of the present invention, the cover includes a key portion movably engaged with a key groove formed along the fluid flow direction on the inner periphery of the casing. When the second pressure is greater than the first pressure, the key portion moves upstream along the key groove to increase the flow rate of the fluid flowing through the recirculation flow path, and the first pressure is When the pressure is greater than two pressures, it is preferable that the key portion moves downstream along the key groove to reduce the flow rate of the fluid flowing through the recirculation flow path. According to this structure, a recirculation flow path can be opened and closed appropriately because a cover moves along a keyway.

  In the recirculation flow path structure according to the present invention, the inner cylinder is integrally assembled with the cover, and the inner cylinder and the cover are integrated on the upstream side when the second pressure is larger than the first pressure. When the first pressure is larger than the second pressure, the flow rate of the fluid flowing through the recirculation flow path is increased and the flow rate of the fluid flowing through the recirculation flow path is increased. Is preferably reduced. According to this configuration, the recirculation flow path can be appropriately opened and closed by moving the inner cylinder and the cover integrally.

  In the recirculation flow path structure of the present invention, the inner cylinder is arranged so as to be movable along a fluid flow direction by a difference between the first pressure and the second pressure, and the cover is provided with the first pressure. And the second pressure are arranged to be movable along the fluid flow direction with respect to the inner cylinder, and the inner cylinder and the cover have the second pressure larger than the first pressure. And when the first pressure is greater than the second pressure, the fluid moves to the downstream side and moves to the upstream side, respectively. It is preferable to reduce the flow rate of the fluid flowing through. According to this configuration, the recirculation flow path can be appropriately opened and closed by moving the inner cylinder and the cover, respectively.

  The recirculation flow path structure of the present invention preferably includes an urging means for urging the cover in the same direction as the first pressure or the second pressure. According to this configuration, it is possible to appropriately open and close the recirculation flow path by appropriately moving the cover.

  An exhaust turbine turbocharger according to the present invention includes a turbine driven by exhaust gas discharged from an engine, a compressor driven by transmission of rotation of the turbine via a rotating shaft, and the turbine and the compressor being freely rotatable. A rotating shaft connected to the casing, a casing, and the recirculation flow path structure.

  According to this configuration, the recirculation channel can be appropriately opened and closed.

  The engine of the present invention includes an exhaust turbine supercharger, and an engine main body connected to the exhaust turbine supercharger.

  According to this configuration, the recirculation channel can be appropriately opened and closed.

  According to the present invention, the recirculation channel can be appropriately opened and closed.

FIG. 1 is a cross-sectional view showing an exhaust turbine supercharger according to the first embodiment. FIG. 2 is a cross-sectional view showing the recirculation flow path structure according to the first embodiment. FIG. 3 is a perspective view showing a cover of the recirculation flow path structure according to the first embodiment. FIG. 4 is a cross-sectional view showing the recirculation flow path structure according to the first embodiment. FIG. 5 is a cross-sectional view showing a recirculation flow path structure according to the second embodiment. FIG. 6 is a cross-sectional view showing a recirculation flow path structure according to the second embodiment. FIG. 7 is a cross-sectional view showing a recirculation flow path structure according to the third embodiment. FIG. 8 is a cross-sectional view showing a recirculation flow path structure according to the third embodiment. FIG. 9 is a cross-sectional view showing the cover and the urging means of the recirculation flow path structure according to the fourth embodiment. FIG. 10 is a cross-sectional view showing a modification of the cover and the urging means of the recirculation flow path structure according to the fourth embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined, and when there are a plurality of embodiments, the embodiments can be combined.

[First embodiment]
FIG. 1 is a cross-sectional view showing an exhaust turbine supercharger according to the first embodiment. FIG. 2 is a cross-sectional view showing the recirculation flow path structure according to the first embodiment. The exhaust turbine supercharger 100 is mounted on, for example, automobiles, ships, other industrial machines, blowers, and the like.

  The exhaust turbine supercharger 100 includes a turbine 110, a rotating shaft 120, a compressor 130, a casing 140, and the recirculation flow path structure 1. In the exhaust turbine supercharger 100, the turbine 110 is driven by high-temperature exhaust gas flowing at a high speed discharged from an engine (not shown), and the rotation of the turbine 110 is transmitted via the rotary shaft 120 to drive the compressor 130. The compressor 130 compresses the combustion gas and supplies it to the engine.

  The compressor 130 is accommodated in the casing 140. The casing 140 is provided with a fluid intake port 132 and a compressed fluid discharge port with respect to the impeller 131. In the casing 140, a diffuser 134 is provided between the impeller 131 and the compressed fluid discharge port. When the rotating shaft 120 is rotated by the turbine 110, the integrated impeller 131 is rotated and the compression gas (fluid) is sucked through the fluid intake port 132. The sucked fluid is pressurized by the impeller 131 to become compressed air (compressed fluid), and this compressed fluid passes through the diffuser 134 and is supplied to the engine from the compressed fluid discharge port.

  The casing 140 accommodates the impeller 131 in an internal space, and defines a flow path of a fluid that flows into the impeller 131 (hereinafter referred to as “main flow”). The casing 140 is formed with a key groove 141 in which the key portion 32 of the cover 3 is movably engaged.

  A plurality of key grooves 141 are formed on the inner peripheral surface 140b of the casing 140 at intervals in the circumferential direction. The keyway 141 is formed on the inner peripheral surface 140b along the mainstream flow direction. The keyway 141 has a longer length in the axial direction of the rotation shaft 120 (hereinafter referred to as “axial direction”) than the key portion 32 of the cover 3. The keyway 141 is formed on the upstream side of the end surface 140 a of the casing 140.

  The recirculation flow path structure 1 is arranged on the blade tip side of the impeller 131, in other words, on the radially outer side of the impeller 131, and recirculates the fluid branched from the main flow from the downstream side to the upstream side. The recirculation flow path structure 1 includes an inner cylinder 2, a cover 3, and a recirculation flow path 4 partitioned by a casing 140, the inner cylinder 2 and the cover 3. The recirculation flow path structure 1 increases the flow rate of the fluid flowing through the recirculation flow path 4 when the pressure increase force of the impeller 131 is increased. The recirculation flow path structure 1 opens the recirculation flow path 4 when the pressure boosting force of the impeller 131 increases. The recirculation flow path structure 1 reduces the flow rate of the fluid flowing through the recirculation flow path 4 when the boosting force of the impeller 131 is not high, in other words, when recirculation is not required. In this embodiment, the recirculation flow path structure 1 closes the recirculation flow path 4 when the boosting force of the impeller 131 is not high.

  The inner cylinder 2 defines a fluid recirculation channel 4 between the downstream side and the upstream side of the channel on the blade tip side of the impeller 131. The inner cylinder 2 is disposed in the casing 140 so as to surround the outer periphery of the impeller 131 on the front surface 131a side in the circumferential direction. The inner cylinder 2 includes a cylinder part 21 and a support column 22.

  The cylinder part 21 is formed in a cylindrical shape along the axial direction. In the tube portion 21, a front surface 21 a that is an upstream end surface is located on the upstream side of the front surface 131 a of the impeller 131. In the tube portion 21, the back surface 21 b, which is the downstream end surface, is located on the downstream side of the front surface 131 a of the impeller 131. The cylindrical portion 21 is spaced upstream from the end surface 140a of the casing 140. The cylindrical portion 21 has an inner peripheral surface 21 c that is separated from the blade tip side of the impeller 131. The cylindrical portion 21 has an outer peripheral surface 21 d separated from the inner peripheral surface 140 b of the casing 140.

  The support column 22 fixes the inner cylinder 2 to the inner peripheral surface 140 b of the casing 140. The struts 22 are arranged on the outer peripheral surface 21 d of the cylindrical portion 21 with a gap in the circumferential direction.

  The cover 3 covers the front surface of the inner cylinder 2 and restricts the mainstream from contacting the front surface of the inner cylinder 2. The cover 3 is disposed on the upstream side of the inner cylinder 2. The cover 3 is formed in a cylindrical shape facing the front surface of the inner cylinder 2. The cover 3 is movably disposed along the mainstream flow direction by the difference between the mainstream first pressure F1 acting on the front surface 31a facing the upstream side and the second pressure F2 acting on the back surface 31b. . The cover 3 includes a main body portion 31 and a key portion 32. The main body portion 31 and the key portion 32 are integrally formed.

  The first pressure F <b> 1 is a stagnation pressure generated when the main flow contacts the upstream side of the cover 3. The first pressure F1 increases as the flow rate of the impeller 131 increases.

  The second pressure F2 increases as the pressure increase amount of the impeller 131 increases. In other words, the second pressure F2 is small during the low pressure operation of the impeller 131 and is large during the high pressure operation of the impeller 131.

  The main body 31 is exposed radially inward from the inner peripheral surface 140 b of the casing 140. The main body portion 31 is positioned in the vicinity of the radially inner end portion of the cylindrical portion 21 of the inner cylinder 2 at the radially inner end portion. The main body 31 is formed in a curved surface that is curved in a convex shape from the upstream side to the downstream side as the front surface 31a goes from the radially outer side to the radially inner side. As for the main-body part 31, the back surface 31b is formed in planar shape.

  The key unit 32 will be described with reference to FIG. FIG. 3 is a perspective view showing a cover of the recirculation flow path structure according to the first embodiment. A plurality of key portions 32 are formed on the outer peripheral surface of the main body portion 31 at intervals in the circumferential direction. The key portion 32 is movably engaged with the key groove 141 of the casing 140. The key portion 32 is movable in the axial direction along the key groove 141 of the casing 140. For example, it is preferable to prevent the casing 140 from adhering to the key groove 141 by applying a lubricant including grease or solid lubricant to the key portion 32.

  The cover 3 configured as described above moves in the axial direction when the key portion 32 moves along the key groove 141 of the casing 140. More specifically, when the second pressure F2 is greater than the first pressure F1, the cover 3 is pushed by the second pressure F2 to move the cover 3 upstream, and the back surface 31b of the main body 31 is the front surface of the tube portion 21. Separated from 21a. The outlet side of the recirculation flow path 4 is opened. The cover 3 increases the flow rate of the fluid flowing through the recirculation flow path 4 when the second pressure F2 is higher than the first pressure F1.

  When the first pressure F1 is greater than the second pressure F2, the cover 3 is pushed by the first pressure F1 and the cover 3 moves downstream, so that the back surface 31b of the main body portion 31 contacts the front surface 21a of the tube portion 21. . The recirculation flow path 4 is closed on the outlet side. The cover 3 reduces the flow rate of the fluid flowing through the recirculation flow path 4 when the first pressure F1 is greater than the second pressure F2.

  The recirculation flow path 4 is a fluid flow path that recirculates from the downstream side to the upstream side on the blade tip side of the impeller 131. More specifically, the recirculation flow path 4 is defined by a flow path defined by the end surface 140 a of the casing 140 and the back surface 21 b of the cylindrical part 21, and an inner peripheral surface 140 b of the casing 140 and an outer peripheral surface 21 d of the cylindrical part 21. The flow path and the flow path defined by the front surface 21a of the cylinder part 21 and the back surface 31b of the main body part 31 communicate with each other. In the recirculation flow path 4, the outlet width d1 is changed by moving the cover 3, and the flow rate of the recirculating fluid is changed. In such a recirculation flow path 4, the fluid flows from between the end surface 140 a of the casing 140 and the back surface 21 b of the tube portion 21, and the fluid flows from between the front surface 21 a of the tube portion 21 and the back surface 31 b of the main body portion 31. Discharge.

  Next, the operation of the recirculation flow path structure 1 will be described.

  With reference to FIG. 2, a description will be given of a small flow rate and high pressure operation of the compressor 130 that requires recirculation. Since the compressor 130 has a small flow rate and a high pressure, the first pressure F1 is small and the second pressure F2 is large. The cover 3 is pushed upstream along the keyway 141 of the casing 140 by the second pressure F <b> 2, and the back surface 31 b of the main body 31 is separated from the front surface 21 a of the tube portion 21. The recirculation flow path 4 has an increased outlet width d1. In other words, the outlet side of the recirculation flow path 4 is opened. A fluid flows into the recirculation flow path 4 to generate a recirculation flow. As the recirculation flow flows into the upstream side of the impeller 131, the flow rate on the upstream side of the impeller 131 increases. Thereby, the stall of the impeller 131 is suppressed and the operating range of the impeller 131 is expanded.

  With reference to FIG. 4, a description will be given of a high flow rate and low pressure operation of the compressor 130 that does not require a recirculation flow. FIG. 4 is a cross-sectional view showing the recirculation flow path structure according to the first embodiment. Since the compressor 130 has a large flow rate and a low pressure, the first pressure F1 is large and the second pressure F2 is small. The cover 3 is pushed downstream along the keyway 141 of the casing 140 by the first pressure F <b> 1, and the back surface 31 b of the main body portion 31 contacts the front surface 21 a of the tube portion 21. The recirculation flow path 4 has an exit width d2 smaller than d1. In other words, the outlet side of the recirculation flow path 4 becomes narrow. The fluid is restricted from flowing into the recirculation flow path 4.

  As described above, when the compressor 130 is operated at a low flow rate and high pressure, the cover 3 moves to open the outlet side of the recirculation flow path 4 to form the recirculation flow path 4. When the compressor 130 is operated at a large flow rate and low pressure, the cover 3 moves to close the outlet side of the recirculation flow path 4 and restrict the fluid from flowing into the recirculation flow path 4.

  As described above, according to the present embodiment, when the compressor 130 is operated at a low flow rate and high pressure, the cover 3 moves to open the outlet side of the recirculation flow path 4 to form the recirculation flow path 4. To do. According to the present embodiment, when the compressor 130 is operated at a large flow rate and low pressure, the cover 3 moves to block the outlet side of the recirculation flow path 4 and restrict the fluid from flowing into the recirculation flow path 4. To do. Thus, according to the present embodiment, the cover 3 can be appropriately moved according to the flow rate and pressure at the operating point of the compressor 130, and the recirculation flow path 4 can be appropriately opened and closed. In the present embodiment, for example, the cover 3 can be moved without using a driving device including an actuator. Thereby, according to this embodiment, the exhaust turbine supercharger 100 can be reduced in size. Moreover, according to this embodiment, the manufacturing cost of the exhaust turbine supercharger 100 can be reduced.

  In the present embodiment, by forming the recirculation flow path 4 at the time of the low flow rate and high pressure operation of the compressor 130, the stall of the impeller 131 can be suppressed and the operating range of the impeller 131 can be expanded.

  In the present embodiment, the efficiency reduction of the compressor 130 can be suppressed by restricting the flow of the fluid into the recirculation flow path 4 at the time of the high flow rate and low pressure operation of the compressor 130.

  In the present embodiment, the cover 3 covers the front surface 21 a of the inner cylinder 2 and restricts the mainstream from contacting the front surface 21 a of the inner cylinder 2. According to the present embodiment, noise generated by the recirculation flow that flows into the recirculation flow path 4 can be reduced.

  According to the present embodiment, the recirculation flow path 4 is not opened by facing the upstream side in the mainstream flow direction but is opened by the cover 3 so as to face radially inward. Thereby, this embodiment can control that a mainstream flows into the recirculation flow path 4 from the exit side of the recirculation flow path 4, and forms a bypass flow. According to the present embodiment, by suppressing the bypass flow as described above, the fluid easily flows into the recirculation flow path 4 from the inlet side of the recirculation flow path 4 even when the compressor 130 has a small flow rate. Thereby, according to this embodiment, it can suppress that the flow volume of the recirculation flow path 4 falls at the time of the small flow volume of the compressor 130. FIG.

[Second Embodiment]
The recirculation flow path structure 1A according to the present embodiment will be described with reference to FIGS. FIG. 5 is a cross-sectional view showing a recirculation flow path structure according to the second embodiment. FIG. 6 is a cross-sectional view showing a recirculation flow path structure according to the second embodiment. The basic configuration of the recirculation flow path structure 1A is the same as that of the recirculation flow path structure 1 of the first embodiment. In the following description, components similar to those in the recirculation channel structure 1 are denoted by the same reference numerals or corresponding reference numerals, and detailed description thereof is omitted.

  In the recirculation channel structure 1A, an inner cylinder 2A and a cover 3A are assembled together. The exit width d3 between the inner cylinder 2A and the cover 3A is constant.

  The inner cylinder 2A is fixed to the key portion 32A of the cover 3A via a support 22A.

  The key portion 32A of the cover 3A is formed so as to protrude downstream from the main body portion 31A. The inner cylinder 2A is integrally assembled to the key portion 32A through a support 22A.

  The inner cylinder 2 </ b> A and the cover 3 </ b> A configured as described above move together in the axial direction as the key portion 32 </ b> A moves along the key groove 141 </ b> A of the casing 140. More specifically, when the second pressure F2 is greater than the first pressure F1, the inner cylinder 2A and the cover 3A are pushed by the second pressure F2, and the inner cylinder 2A and the cover 3A move upstream, The rear surface 21Ab is separated from the end surface 140a of the casing 140. The recirculation flow path 4 is opened on the inlet side. The recirculation flow path 4 has a larger inlet width d4. The cover 3A integrally assembled with the inner cylinder 2A increases the flow rate of the fluid flowing through the recirculation flow path 4 when the second pressure F2 is higher than the first pressure F1.

  When the first pressure F1 is greater than the second pressure F2, the inner cylinder 2A and the cover 3A are pushed by the first pressure F1 to move the inner cylinder 2A and the cover 3A downstream, and the rear surface 21Ab of the cylinder portion 21A It approaches the end surface 140a of the casing 140. The recirculation flow path 4 has an entrance width d5 smaller than d4. The recirculation flow path 4 becomes narrower on the inlet side. The cover 3A integrally assembled with the inner cylinder 2A reduces the flow rate of the fluid flowing through the recirculation flow path 4 when the first pressure F1 is higher than the second pressure F2.

  If the inlet width d5 is zero, the second pressure F2 does not increase even if the flow rate or pressure of the compressor 130 changes after the second pressure F2 acting on the back surface 21Ab of the cylinder portion 21A becomes zero. Therefore, it is preferable to leave a slight gap between the rear surface 21Ab of the cylindrical portion 21A and the end surface 140a of the casing 140 without reducing the inlet width d5 to zero. Thereby, after the inlet side of the recirculation flow path 4 is narrowed, the second pressure F2 acting on the back surface 21Ab of the cylinder portion 21A increases in accordance with changes in the flow rate and pressure of the compressor 130, and the inner cylinder 2A and The cover 3A moves to open the inlet side of the recirculation flow path 4.

  As described above, when the compressor 130 is operated at a small flow rate and high pressure, the inner cylinder 2A and the cover 3A move as a unit, and the inlet side of the recirculation flow path 4 is opened to form the recirculation flow path 4. When the compressor 130 is operated at a large flow rate and a low pressure, the inner cylinder 2A and the cover 3A move as a unit, and the inlet side of the recirculation flow path 4 is narrowed to restrict fluid from flowing into the recirculation flow path 4. To do.

  As described above, according to the present embodiment, when the compressor 130 is operated at a low flow rate and high pressure, the inner cylinder 2A and the cover 3A move as a unit, and the inlet side of the recirculation flow path 4 is opened. A recirculation flow path 4 is formed. According to the present embodiment, when the compressor 130 is operated at a large flow rate and low pressure, the inner cylinder 2A and the cover 3A move as a unit, and the inlet side of the recirculation flow path 4 is narrowed to the recirculation flow path 4. Regulate the inflow of fluid. As described above, according to the present embodiment, the inner cylinder 2A and the cover 3A are integrally movable in accordance with the flow rate and pressure at the operating point of the compressor 130, and the recirculation flow path 4 can be appropriately opened and closed. In the present embodiment, for example, the inner cylinder 2A and the cover 3A can be moved integrally without using a driving device including an actuator. Thereby, according to this embodiment, the exhaust turbine supercharger 100 can be reduced in size. Moreover, according to this embodiment, the manufacturing cost of the exhaust turbine supercharger 100 can be reduced.

[Third embodiment]
The recirculation flow path structure 1B according to the present embodiment will be described with reference to FIGS. FIG. 7 is a cross-sectional view showing a recirculation flow path structure according to the third embodiment. FIG. 8 is a cross-sectional view showing a recirculation flow path structure according to the third embodiment.

  In the recirculation flow path structure 1B, the inner cylinder 2B is movably engaged with the key groove 141B of the casing 140, and the cover 3B is movably engaged with the key groove 24B of the inner cylinder 2B.

  The inner cylinder 2B includes a cylinder part 21B, a support 22B, a key part 23B, and a key groove 24B.

  The column 22B fixes the cylinder portion 21B to the key portion 23B.

  The key part 23B is formed on the outer side in the radial direction of the column 22B. The key portion 23B is movably engaged with the key groove 141B of the casing 140. The key portion 23B is movable in the axial direction along the key groove 141B of the casing 140. For example, a lubricant such as grease or solid lubricant may be applied to the key portion 23B to suppress sticking of the casing 140 to the key groove 141B.

  A plurality of key grooves 24B are formed on the inner peripheral surface of the key portion 23B at intervals in the circumferential direction. The key groove 24B engages with the key portion 32B of the cover 3B so as to be movable. The key groove 24B has a length longer in the axial direction than the key portion 32B of the cover 3B.

  The inner cylinder 2 </ b> B configured as described above moves in the axial direction as the key portion 23 </ b> B moves along the key groove 141 </ b> B of the casing 140. More specifically, when the second pressure F2 is greater than the first pressure F1, the inner cylinder 2B is pushed by the second pressure F2 to move the inner cylinder 2B upstream, and the rear surface 21Bb of the cylinder portion 21B is connected to the casing 140. Separated from the end face 140a. The recirculation flow path 4 has an inlet width d7. The recirculation flow path 4 is opened on the inlet side.

  When the first pressure F1 is greater than the second pressure F2, the inner cylinder 2B is pushed by the first pressure F1 to move the inner cylinder 2B to the downstream side, and the back surface 21Bb of the cylinder portion 21B approaches the end surface 140a of the casing 140. . The recirculation flow path 4 becomes narrower on the inlet side. The recirculation flow path 4 has an inlet width d9 smaller than d7.

  The cover 3B has a main body portion 31B and a key portion 32B.

  The key portion 32B is movably engaged with the key groove 24B of the inner cylinder 2B. The key portion 32B is movable in the axial direction along the key groove 24B of the inner cylinder 2B. For example, a lubricant such as grease or solid lubricant may be applied to the key portion 32B to suppress sticking of the inner cylinder 2B to the key groove 24B.

  The cover 3B configured as described above moves in the axial direction when the key portion 32B moves along the key groove 24B of the inner cylinder 2B. More specifically, when the second pressure F2 is greater than the first pressure F1, the cover 3B is pushed by the second pressure F2 to move the cover 3B to the upstream side, and the back surface 31Bb of the main body portion 31B is moved to the front surface of the cylinder portion 21B. Separated from 21Ba. The recirculation flow path 4 has an exit width d6. The outlet side of the recirculation flow path 4 is opened.

  When the first pressure F1 is greater than the second pressure F2, the cover 3B is pushed by the first pressure F1 to move the cover 3B to the downstream side, and the back surface 31Bb of the main body portion 3B1 approaches the front surface 21Ba of the cylinder portion 21B. The outlet side of the recirculation channel 4B becomes narrow. The recirculation flow path 4 has an outlet width d8 smaller than d6.

  As described above, when the compressor 130 is operated at a low flow rate and high pressure, the inner cylinder 2B and the cover 3B are moved to open the inlet side and the outlet side of the recirculation flow path 4 so that the recirculation flow path 4 is Form. When the compressor 130 is operated at a large flow rate and low pressure, the inner cylinder 2B and the cover 3B move, narrowing the inlet side and the outlet side of the recirculation flow path 4, and the fluid flows into the recirculation flow path 4. To regulate that.

  As described above, according to the present embodiment, when the compressor 130 is operated at a low flow rate and high pressure, the inner cylinder 2B and the cover 3B move, and the inlet side and the outlet side of the recirculation flow path 4 are opened. Thus, the recirculation flow path 4 is formed. According to the present embodiment, when the compressor 130 is operated at a large flow rate and low pressure, the inner cylinder 2B and the cover 3B are moved to narrow the inlet side and the outlet side of the recirculation flow path 4 so that the recirculation flow is reduced. The flow of fluid into the path 4 is restricted. In the present embodiment, when the recirculation is unnecessary, the inlet side and the outlet side of the recirculation flow path 4 become narrower, so that the recirculation flow path can be more reliably compared to the first embodiment and the second embodiment. Inflow of fluid to 4 can be restricted.

  In the present embodiment, for example, the inner cylinder 2B and the cover 3B can be moved without using a driving device including an actuator. Thereby, according to this embodiment, the exhaust turbine supercharger 100 can be reduced in size. Moreover, according to this embodiment, the manufacturing cost of the exhaust turbine supercharger 100 can be reduced.

[Fourth embodiment]
A recirculation flow path structure 1C according to the present embodiment will be described with reference to FIG. FIG. 9 is a cross-sectional view showing the cover and the urging means of the recirculation flow path structure according to the fourth embodiment.

  The recirculation flow path structure 1C includes an inner cylinder 2C, a cover 3C, and an urging means 5C.

  The urging means 5C urges the cover 3C in the same direction as the first pressure F1 or the second pressure F2. In the present embodiment, the urging means 5C urges the cover 3C in the same direction as the first pressure F1, in other words, in the direction of decreasing the flow rate of the fluid flowing through the recirculation flow path 4. The urging means 5C urges the cover 3C to move in the direction of narrowing the recirculation flow path 4. In the present embodiment, the urging means 5C urges the cover 3C in a direction to approach the inner cylinder 2C. The biasing means 5C is an elastic body including a coil spring and a disc spring, for example.

  In the recirculation flow path structure 1C configured as described above, the cover 3C is urged by the urging means 5C in a direction to approach the inner cylinder 2C. As a result, when the second pressure F2 becomes equal to or lower than a predetermined value, the recirculation flow path 4 is narrowed by pushing the cover 3C closer to the inner cylinder 2C by the urging means 5C.

  As described above, according to the present embodiment, when the second pressure F2 becomes equal to or lower than a predetermined value, the recirculation flow path 4 is narrowed by pushing the cover 3C closer to the inner cylinder 2C by the urging means 5C. be able to.

  For example, when the cover 3C is disposed at a position where the first pressure F1 is excessive, the urging means 5C is directed to the cover 3C in the same direction as the second pressure F2, in other words, the recirculation flow path 4 The fluid may be urged in the direction of increasing the flow rate of the fluid flowing through

  As shown in FIG. 10, the urging means is a motor, the key portion 32D of the cover 3D is threaded to engage with the output shaft of the motor, and the cover 3D is moved by the motor in the same direction as the first pressure F1 or the second pressure F2. May be energized. FIG. 10 is a cross-sectional view showing a modification of the cover and the urging means of the recirculation flow path structure according to the fourth embodiment.

DESCRIPTION OF SYMBOLS 1 Recirculation flow path structure 2 Inner cylinder 21 Cylinder part 22 Support | pillar 3 Cover 31 Main body part 32 Key part 4 Recirculation flow path 100 Exhaust turbine supercharger 110 Turbine 120 Rotating shaft 130 Compressor 131 Impeller 140 Casing 141 Keyway F1 1st Pressure F2 Second pressure

Claims (7)

A cylindrical inner cylinder disposed in a casing that accommodates the impeller in an inner space and surrounds the outer periphery of the front side of the impeller in the circumferential direction, in a casing that divides a fluid flow path;
The first pressure of the fluid acting on the front surface facing the upstream side of the flow path and the fluid acting on the back surface are formed in a cylindrical shape facing the front surface of the inner cylinder on the upstream side of the flow path from the inner cylinder. A cover arranged to be movable along the fluid flow direction by a difference from the second pressure;
With
The inner cylinder defines a recirculation flow path between a downstream side and an upstream side of the flow path,
When the second pressure is greater than the first pressure, the cover moves upstream to increase the flow rate of the fluid flowing through the recirculation flow path, and the first pressure is greater than the second pressure. , Moving downstream to reduce the flow rate of fluid flowing through the recirculation flow path,
A recirculation flow path structure characterized by that. The cover is movably engaged with a key groove formed along the fluid flow direction on the inner periphery of the casing;
With
When the second pressure is greater than the first pressure, the cover moves the key portion upstream along the key groove to increase the flow rate of the fluid flowing through the recirculation flow path. 2. When the one pressure is larger than the second pressure, the key portion moves downstream along the key groove to reduce the flow rate of the fluid flowing through the recirculation flow path. The recirculation flow path structure described in 1. The inner cylinder is assembled integrally with the cover,
When the second pressure is greater than the first pressure, the inner cylinder and the cover move together upstream to increase the flow rate of the fluid flowing through the recirculation flow path, and the first pressure is 2. The recirculation flow path structure according to claim 1, wherein when the pressure is greater than the second pressure, the recirculation flow path structure moves integrally as a downstream side to reduce the flow rate of the fluid flowing through the recirculation flow path. The inner cylinder is arranged to be movable along a fluid flow direction due to a difference between the first pressure and the second pressure,
The cover is arranged to be movable along the fluid flow direction with respect to the inner cylinder by a difference between the first pressure and the second pressure,
When the second pressure is greater than the first pressure, the inner cylinder and the cover move to the upstream side to increase the flow rate of the fluid flowing through the recirculation flow path, and the first pressure is 2. The recirculation flow path structure according to claim 1, wherein when the pressure is larger than the second pressure, the recirculation flow path structure moves to the downstream side to reduce the flow rate of the fluid flowing through the recirculation flow path.   The recirculation flow path structure according to any one of claims 1 to 4, further comprising: an urging unit that urges the cover in the same direction as the first pressure or the second pressure. A turbine driven by exhaust gas discharged from the engine;
A compressor in which rotation of the turbine is transmitted through a rotating shaft and driven;
A rotating shaft that rotatably connects the turbine and the compressor;
A casing,
The recirculation flow path structure according to any one of claims 1 to 5,
An exhaust turbine supercharger comprising: An exhaust turbine supercharger according to claim 6,
An engine body connected to the exhaust turbine supercharger;
An engine comprising:

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