JP6587406B2 - Compressor inspection device - Google Patents

Description

  The present invention relates to an inspection apparatus that inspects a compressor rotor having a plurality of blades.

  2. Description of the Related Art Conventionally, there has been known an apparatus that arranges an eddy current sensor or the like in a compressor housing and calculates some parameters related to the compressor using the output of the eddy current sensor. A typical example of such a device is a device for detecting the number of rotations of a compressor rotor used in the compressor, for example, the number of revolutions of a compressor rotor (impeller) of an exhaust turbocharger of an internal combustion engine.

  As an apparatus for detecting the rotational speed of such a compressor rotating body, for example, a pressure sensor that outputs a signal in response to pressure fluctuation caused by passage of a blade of the compressor rotating body in a compressor housing that houses the compressor rotating body. Have been proposed (for example, Patent Document 1). In particular, the apparatus described in Patent Document 1 analyzes the frequency of the signal from the pressure sensor, measures the fundamental frequency of the signal, and calculates the rotational speed of the compressor rotor based on this fundamental frequency. According to Patent Document 1, it is said that the rotation speed of the compressor rotating body can be detected by using the pressure sensor regardless of the thickness of the blade of the compressor rotating body.

  Further, as another device for detecting the rotation speed of the compressor rotating body, a rotation speed sensor for detecting the passage of the blade by generating an eddy current in the blade of the compressor rotating body is used in the compressor housing that houses the compressor rotating body. What has been proposed. In particular, the rotation speed sensor described in Patent Document 2 includes a coil that generates a magnetic field when energized, and a U-shaped core that emits the magnetic field generated by the coil to a space through which the blade passes. According to Patent Document 2, by using such a rotational speed sensor, it is possible to detect the passage of the blade even if the detection target is as thin as the blade.

JP 2003-240788 A Japanese Unexamined Patent Publication No. 2015-34780

  By the way, in manufacturing a compressor, a shape error (an error with respect to a designed shape) or the like often occurs for each compressor. For this reason, in order to eliminate, for example, a compressor rotating body having a large shape error, it is necessary to detect the shape error of the compressor rotating body in the manufacturing stage of the compressor. In addition, abnormalities such as surging and missing or broken compressor blades may occur while the compressor is in use, but it is necessary to detect these abnormalities quickly in order to use the compressor properly. is there. Therefore, there is a need for an inspection apparatus that performs the above-described inspection at the time of manufacture or use of the compressor with a simple configuration.

  Therefore, in view of the above problems, an object of the present invention is to provide an inspection device that can perform an inspection of a compressor with a simple configuration at the time of manufacture or use of the compressor.

  In order to solve the above-mentioned problem, in the first invention, an inspection apparatus for inspecting a compressor rotating body having a plurality of blades, which is arranged so as to face the end face in the radial direction or the end face in the axial direction of the blade. And a detection device that detects the state of the compressor rotating body based on the output of the sensor, the sensor including an end face of each blade passing in front of the sensor, and a detection unit of the sensor The distance between each of the blades or in front of the sensor is detected, and the detection device detects the distance detected by the sensor or the passage of each blade when the compressor rotor is rotated at a constant angular velocity. An inspection device is provided that detects the state of the compressor rotor based on timing.

  In a second invention, in the first invention, the detection device calculates a time interval during which at least one pair of blades of the plurality of blades passes in front of the sensor based on an output of the sensor. Then, a shape error of the compressor rotor is calculated based on the calculated time interval.

  According to a third aspect, in the first or second aspect, the detection device is configured such that the compressor rotating body is based on a minimum value of the distance detected by the sensor when each blade passes in front of the sensor. The shape error is calculated.

  In a fourth invention, in any one of the first to third inventions, the detection device is a minimum value of the distance detected by the sensor when the same blade passes a plurality of times in front of the sensor. The runout of the compressor rotating body is calculated based on the variation of the above.

  ADVANTAGE OF THE INVENTION According to this invention, the test | inspection apparatus which can perform the test | inspection of the compressor at the time of manufacture or use of a compressor with a simple structure is provided.

FIG. 1 is a sectional view schematically showing a compressor of an exhaust turbocharger of an internal combustion engine. FIG. 2 is a plan view schematically showing a compressor rotor (impeller) used in the compressor shown in FIG. FIG. 3 is a diagram schematically showing the detection principle by the eddy current sensor. FIG. 4 is a diagram showing the transition of the output of the eddy current sensor when the compressor rotating body is rotated. FIG. 5 is a diagram showing the transition of the output of the eddy current sensor when the compressor rotating body is rotated. FIG. 6 is a diagram showing the transition of the angular velocity detected while the compressor rotor rotates once. FIG. 7 is a plan view similar to FIG. 2, schematically showing the compressor rotor. FIG. 8 is a view similar to FIG. 4 showing the transition of the output of the eddy current sensor. FIG. 9 is a cross-sectional view schematically showing the compressor rotor and the eddy current sensor. FIG. 10 is a view similar to FIG. 8 showing the transition of the output of the eddy current sensor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are assigned to similar components.

<Compressor configuration>
First, with reference to FIG.1 and FIG.2, the compressor in which a test | inspection is performed by the test | inspection apparatus of this invention is demonstrated. FIG. 1 is a cross-sectional view schematically showing a compressor of an exhaust gas turbocharger of an internal combustion engine, and an inspection apparatus of the present invention for inspecting a compressor rotating body is used for this compressor. FIG. 2 is a plan view schematically showing a compressor rotating body (impeller) used in the compressor shown in FIG.

  As shown in FIG. 1, the compressor 1 includes a compressor rotator 2 that compresses gas and a housing 3 that houses the compressor rotator 2.

  The compressor rotor 2 is connected to a turbine (not shown) of an exhaust turbocharger via a shaft 4 and extends from the surface of the center body 21 in the radial direction or the axial direction of the compressor rotor 2. A plurality of blades 22. The central body 21 is fixed to the shaft 4 so that the axis L thereof is coaxial with the axis of the shaft 4.

  As can be seen from FIG. 2, the compressor rotor 2 of the present embodiment has 12 blades 22 having the same shape and arranged at equal intervals. In FIG. 2, the blades are numbered (B1 to B12) for easy understanding of the description in the present specification. The number of blades 22 is not limited to 12 and may be more than 12 or less than 12. Further, in the compressor rotating body 2 of the present embodiment, the plurality of blades 22 are configured to extend in the radial direction or the axial direction of the compressor rotating body 2. However, the plurality of blades 22 may have any shape such as a curved shape as long as the fluid flowing into the compressor 1 can be compressed. Further, the blades 22 are not necessarily arranged at equal intervals, and a part or all of the blades 22 may be configured to have a shape different from that of the other blades.

  Referring to FIG. 1, the housing 3 has a central passage 31 that extends through the center of the housing 3 and an annular passage 32 that extends around the central passage 31. One end of the central passage 31 is open and constitutes an inlet 33 through which fluid flows. An annular passage 32 is disposed around the other end of the central passage 31, and the compressor rotor 2 is disposed in the central passage 31 inside the annular passage 32. Therefore, the fluid flowing in from the inlet 33 flows out through the central passage 31 and into the annular passage 32 via the compressor rotor 2.

  The compressor rotor 2 can rotate around its axis L in the housing 3. Further, the compressor rotor 2 is configured such that, when rotated, the radial end of the blade 22 moves in the circumferential direction along the inner peripheral surface with a slight gap from the inner peripheral surface of the housing 3. The

<Eddy current sensor>
In the present embodiment, the eddy current sensor 5 is provided in the housing 3. The eddy current sensor is a sensor that generates an output corresponding to the distance between the sensor detection unit and the metal material to be measured. The detection principle of the eddy current sensor will be briefly described below with reference to FIG.

  The eddy current sensor 5 has a coil 25 that generates a magnetic field by an alternating excitation current at its detection unit. When the blade 22 passes through the magnetic field X generated by the coil 25, an eddy current Y is generated in the blade 22 so as to cancel the magnetic field generated by the coil 25. The strength of the magnetic field X changes due to the eddy current generated in the blade 22, and as a result, the value of the current flowing through the coil 25 changes. Therefore, in the eddy current sensor 5, since the current value flowing through the coil 25 changes when the blade 22 passes through the magnetic field, the passage of the blade 22 is detected by detecting the current value (output value) flowing through the coil 25. Like to do. Specifically, it is determined that the time when the output of the eddy current sensor 5 reaches a peak is the time when the blade 22 passes in front of the detection unit of the eddy current sensor 5 (that is, a predetermined angular position). I have to. Therefore, the eddy current sensor 5 can detect that the blade 22 has passed in front of the detection unit of the eddy current sensor 5, that is, the passage timing of the blade 22.

  In the eddy current sensor 5, when the blade 22 passes the magnetic field X generated by the coil 25, the magnitude of the eddy current Y generated in the blade 22 is the distance between the detection unit of the eddy current sensor 5 and the blade 22. The larger the distance, the larger the eddy current Y is generated. As described above, when the eddy current Y generated in the blade 22 increases, the strength of the magnetic field X also changes greatly. As a result, the value of the current flowing through the coil 25 also changes greatly. Therefore, the eddy current sensor 5 detects the distance between the end surface of the blade 22 facing the eddy current sensor 5 and the detection unit of the eddy current sensor 5 when the blade 22 passes in front of the detection unit of the eddy current sensor 5. You can also

  In the present embodiment, the eddy current sensor 5 is disposed so as to face the radial end surface 22a of the blade 22 of the compressor rotor 2 and to extend in the normal direction of the radial end surface 22a of the blade 22. Further, the eddy current sensor 5 is disposed in the housing 3 on the inlet side of the compressor rotor 2. In the example shown in FIG. 1, the eddy current sensor 5 is disposed in the housing 3 adjacent to the inlet side end face 22 b of the blade 22 of the compressor rotor 2. The eddy current sensor 5 is connected to an electronic control unit (ECU) 6 that also functions as a detection device that detects the state of the compressor rotor 2, and an output signal of the eddy current sensor 5 is input to the ECU 6.

  Here, the temperature of the blade 22 of the compressor rotor 2 gradually increases from the inlet side toward the outlet side. This is because the fluid flowing through the compressor rotor 2 is pressurized from the inlet side toward the outlet side. In the present embodiment, since the eddy current sensor 5 is disposed in the housing 3 on the inlet side of the compressor rotor 2, it is disposed in a relatively low temperature region. For this reason, the influence of heat on the eddy current sensor 5 can be reduced.

  In the present embodiment, the eddy current sensor 5 is used as a sensor. However, if it is possible to detect the distance between the end face of each blade passing in front of the sensor and the detection part of the sensor or that each blade has passed in front of the sensor, another sensor can be used instead of the eddy current sensor. It may be used. An example of such a sensor is an electromagnetic pickup (MPU) sensor. The MPU sensor is a sensor having a magnet and a detection coil in its detection unit. In such an MPU sensor, when a blade, which is a magnetic body, approaches or separates from the MPU sensor, the magnetic flux penetrating the detection coil changes, and the induced electromotive force of the detection coil changes accordingly. Thereby, the passage of the blade 22 in front of the detection unit of the MPU sensor can be detected.

  FIG. 4 is a diagram showing the transition of the output of the eddy current sensor 5 when the eddy current sensor 5 is used in the configuration as described above. 4A shows a transition when the rotation speed of the compressor rotor 2 is relatively slow, and FIG. 4B shows a transition when the rotation speed of the compressor rotor 2 is relatively slow.

  As described above, in the eddy current sensor 5, the output value increases as the distance between the detection unit of the eddy current sensor 5 and the object (for example, the blade 22) passing therethrough becomes shorter. Therefore, when the blade 22 passes in front of the detection unit of the eddy current sensor 5, the output of the eddy current sensor 5 increases rapidly. Therefore, the output changed into a convex shape in FIG. 4 means that the blade 22 has passed. Further, the maximum value of the output changed into a convex shape in FIG. 4 means the minimum value of the distance between the detection portion of the eddy current sensor 5 and the radial end face 22a of the blade 22 when each blade 22 passes. . In other words, the maximum value of the output changed into a convex shape in FIG. 4 means the width in the radial direction of the blade 22 in the region where the detection unit of the eddy current sensor 5 faces. In addition, the number in FIG. 4 has shown the number (B1-B12) of the braid | blade 22 which passed in front of the detection part of the eddy current sensor 5. FIG.

  As shown in FIG. 4A, when the rotational speed of the compressor rotor 2 is relatively slow, the output value of the eddy current sensor 5 suddenly rises and falls as the blade 22 passes, The period during which two adjacent blades 22 pass is kept constant at a low value.

  On the other hand, as shown in FIG. 4B, when the rotational speed of the compressor rotor 2 is relatively high, before the output value of the eddy current sensor 5 that has risen with the passage of one blade 22 has fallen completely. In addition, the output value starts to rise as the next blade 22 passes. Therefore, as shown in FIG. 4B, the output value of the eddy current sensor 5 is not maintained constant even during the period during which two adjacent blades 22 pass. However, even in this case, since the time when the output value of the eddy current sensor 5 becomes maximum indicates the passage of the blade 22, the blade 22 has passed in front of the detection unit of the eddy current sensor 5. Can be accurately detected.

<Instantaneous angular velocity detection>
In this embodiment, the ECU 6 calculates the instantaneous angular velocity of the compressor rotor 2 based on the output of the eddy current sensor 5. Below, the calculation method of the instantaneous angular velocity of the compressor rotary body 2 is demonstrated using FIG. In the example shown in FIG. 4, the time t1 is the time when the output of the eddy current sensor 5 shows a peak as the first blade B1 passes in front of the eddy current sensor 5. Similarly, when the second blade B2, the third blade B3, and the fourth blade B4 pass in front of the eddy current sensor 5 and the output of the eddy current sensor 5 shows a peak, they are time t2, t3, and t4, respectively. .

  In this case, the time interval Δt1 from when the first blade B1 passes before the eddy current sensor 5 to when the second blade B2 passes can be expressed as t2-t1. On the other hand, in this embodiment, since 12 blades are provided at equal intervals, the angular interval between the first blade B1 and the second blade B2 is basically 2π / 12 (rad). . Therefore, the instantaneous angular velocity of the compressor rotating body 2 from when the first blade B1 passes through the second blade B2 before the eddy current sensor 5 (hereinafter referred to as “instantaneous angular velocity after passing through the first blade”). ) 1 is calculated as 2π / (12 × Δt1).

  Similarly, the time interval Δt2 between the second blade B2 and the third blade B3 can be expressed as t2-t3, and the time interval Δt3 between the third blade B3 and the fourth blade B4 can be expressed as t3-t4. . Therefore, the instantaneous angular velocity ω2 of the compressor rotating body 2 from the passage of the second blade B2 to the passage of the third blade B3 in front of the eddy current sensor 5, that is, the instantaneous angular velocity after passing through the second blade B2. ω2 is calculated as 2π / (12 × Δt2). Similarly, the instantaneous angular velocity ω3 of the compressor rotating body 2 from the passage of the third blade B3 to the passage of the fourth blade B4 in front of the eddy current sensor 5, that is, the instantaneous moment after the passage of the third blade B3. The angular velocity ω3 is calculated as 2π / (12 × Δt3).

Therefore, according to the present embodiment, when the number of the blade 22 is represented by i, a pair of adjacent blades (that is, the i-th blade Bi and the (i + 1) th blade B (i + 1)) based on the output of the eddy current sensor 5. ) During the passage in front of the eddy current sensor 5 is calculated. Based on the time interval Δti calculated in this way and the angular interval between adjacent pairs of blades, the instantaneous angular velocity ωi after passing through the i-th blade Bi, that is, the instantaneous angular velocity of the compressor rotor 2. ωi is calculated. Specifically, the angular interval αi between adjacent pairs of blades (i-th blade Bi and (i + 1) -th blade B (i + 1)) as expressed by the following formula (1) is calculated as a time interval between these blades. By dividing by Δti, the instantaneous angular velocity ωi after passing through the i-th blade is calculated. Further, in the compressor rotating body 2 in which N blades are provided at equal intervals in the circumferential direction, the instantaneous angular velocity ωi is calculated by the following equation (2).
ωi = αi / Δti (1)
ωi = 2π / (N × Δti) (2)

  In the above-described embodiment, the instantaneous angular velocity ω is based on the time interval at which a pair of adjacent two blades 22 pass a predetermined angular position in the housing 3 (before the detection unit of the eddy current sensor 5). Thus, it is calculated as an instantaneous angular velocity while both blades pass through a predetermined angular position. However, the pair of blades for calculating the instantaneous angular velocity ω may not necessarily be the two adjacent blades 22. For example, as shown in FIG. 5, the time interval Δt1 from the passage of the first blade B1 to the passage of the third blade B3, or the passage of the first blade B1 to the passage of the fourth blade B4. The instantaneous angular velocity may be calculated based on the time interval between two or more blades separated in the circumferential direction, such as the time interval Δt1 ′.

<Shape error of compressor rotor related to angular velocity>
Here, FIG. 6 shows an example in which the instantaneous angular velocity of the compressor rotator 2 is calculated by the ECU 6 while the compressor rotator 2 is rotated at a constant angular velocity. In FIG. 6, the horizontal axis represents the blade number, and the vertical axis represents the instantaneous angular velocity after passing through the blade of the corresponding blade number.

  In the example shown in FIG. 6, the compressor rotor 2 is rotated at a constant angular velocity. Therefore, at this time, the calculated instantaneous angular velocity ω should be a constant value. However, actually, as shown in FIG. 6, the calculated instantaneous angular velocity ω is not necessarily constant after passing through each blade 22. For example, in the example shown in FIG. 6, the instantaneous angular velocity after passing through the second blade is slower than the instantaneous angular velocity after passing through the first blade.

  In this regard, the inventors of the present application conducted extensive research and found that the calculated instantaneous angular velocity ω does not have a constant value because the shape error of the blade 22 of the compressor rotor 2 (within the shape tolerance range). We found out that there was a main cause of error. In other words, the compressor rotor 2 has a shape error for each solid, and it has been found that this shape error causes an error in the instantaneous angular velocity calculated by the ECU 6. Hereinafter, the relationship between the calculated instantaneous angular velocity ω and the shape error of the blade 22 will be described with reference to FIG.

  FIG. 7 is a plan view similar to FIG. 2, schematically showing the compressor rotor. 7 indicates the shape of the blade 22 when the blade 22 of the compressor rotor 2 is formed as designed. In the example shown in FIG. 7, the plurality of blades 22 are designed to have the same shape at regular intervals. In the example shown in FIG. 7, the second blade B2 and the tenth blade B10 have a shape error with respect to the designed blade shape. Specifically, the second blade B2 has a shape shifted to the first blade side in the circumferential direction with respect to the design shape. Further, the tenth blade B10 has a shape shifted radially outward from the design shape.

  When an error occurs in the blade shape in this way, the angular interval α between the blades changes. In the example shown in FIG. 7, the shape of the second blade B2 is a shape that is shifted in the circumferential direction with respect to the designed shape. As a result, in the region facing the eddy current sensor 5, the actual angular interval between the first blade B1 and the second blade B2 is α1, which is smaller than the design value β1. Conversely, the actual angular interval between the second blade B2 and the third blade B3 is α2, which is larger than the design value β2. Accordingly, the actual angular interval α1 between the first blade B1 and the second blade B2 is smaller than the actual angular interval α2 between the second blade B2 and the third blade B3. On the other hand, in calculating the angular velocity, a design value is used instead of the actual angular interval between the blades. Therefore, even if the compressor rotor 2 rotates at a constant rotation angle, the instantaneous angular velocity ω1 based on the time interval Δt1 from the first blade B1 to the second blade B2 is the second blade B2 to the third blade. It is calculated as being faster than the instantaneous angular velocity ω2 based on the time interval Δt2 up to B3. As a result, as shown in FIG. 6, the instantaneous angular velocity after passing through the first blade B1 is calculated to be faster than the instantaneous angular velocity after passing through the second blade B2.

  In the example shown in FIG. 7, the tenth blade B <b> 10 has a shape shifted outward in the circumferential direction with respect to the design shape. As a result, the actual angular interval between the ninth blade B9 and the tenth blade B10 is α9 which is smaller than the design value β9. In addition, the actual angular interval between the tenth blade B10 and the eleventh blade B11 is α10 which is larger than the design value β10. As a result, even if the compressor rotor 2 rotates at a constant rotation angle, the instantaneous angular velocity after passing through the ninth blade B9 is calculated to be faster than the instantaneous angular velocity after passing through the tenth blade B10. .

  Therefore, as a result of a shape error occurring in the blade 22 of the compressor rotor 2, an error occurs in the circumferential interval between the blades 22 with respect to the design interval in the region facing the detection unit of the eddy current sensor 5. The instantaneous angular velocity calculated by the ECU 6 changes without being constant while the compressor rotor 2 rotates once while the compressor rotor 2 is rotated at a constant angular velocity. Therefore, in the present embodiment, the shape error of the blade 22 of the compressor rotor 2 is calculated based on the angular velocity calculated as described above. In other words, in this embodiment, the time interval during which at least one pair of blades 22 of the plurality of blades 22 passes in front of the detection unit of the eddy current sensor 5 is calculated based on the output of the eddy current sensor 5. At the same time, it can be said that the shape error of the compressor rotor is calculated based on the calculated time interval.

  Specifically, the compressor rotating body 2 is rotated at a constant angular velocity by, for example, flowing a fluid (steady flow) at a constant flow rate into the turbine of the exhaust turbocharger. At this time, based on the output of the eddy current sensor 5, as described above, the ECU 6 calculates the angular velocity of the compressor rotator 2 during one rotation of the compressor rotator 2. For example, the difference or ratio between the maximum value and the minimum value of the angular velocity of the compressor rotor 2 during one rotation of the compressor rotor 2 calculated in this way is equal to or greater than a predetermined value. In some cases, it is determined that a large shape error has occurred in the blade 22 of the compressor rotor 2. On the contrary, when this difference or ratio is less than a predetermined value, it is determined that there is no large shape error in the blade 22 of the compressor rotor 2. Thereby, the shape error generated in the blade 22 of the compressor rotor 2 can be accurately detected.

  Further, based on the instantaneous angular velocity after passing through each blade calculated by the ECU 6, it is possible to identify the blade 22 in which a shape error has occurred. For example, as shown in FIG. 6, when the angular velocity after passing through the first blade B1 is high and the angular velocity after passing through the second blade B2 is low, the second blade B2 is large as shown in FIG. It can be determined that a shape error has occurred. In particular, when only the instantaneous angular velocity after passing one blade among the instantaneous angular velocities after passing through each blade calculated by the ECU 6 is significantly different from the instantaneous angular velocity after passing through another blade. It can be determined that the blade 22 has an abnormality such as breakage or loss.

<Shape error of compressor rotor related to minimum distance>
By the way, the maximum value of the output of the eddy current sensor 5 when each blade 22 passes in front of the detection unit of the eddy current sensor 5 is not necessarily the same as shown in FIG. FIG. 8 is a view similar to FIG. 4 showing the transition of the output of the eddy current sensor 5. In the example shown in FIG. 8, the maximum value V1 of the output when the first blade B1 passes in front of the detection unit of the eddy current sensor 5 is smaller than the average maximum value Va for all the blades. Yes.

  Here, as described above, the eddy current sensor 5 determines the distance between the radial end surface 22a of the blade 22 and the detection unit of the eddy current sensor 5 when the blade 22 passes in front of the detection unit of the eddy current sensor 5. It can also be detected. Therefore, the fact that the maximum value of the output of the eddy current sensor 5 is not the same means that the minimum value of the distance between the radial end face 22a of each blade 22 and the detection part of the eddy current sensor 5 is not constant. . In the example shown in FIG. 8, it means that the radial end surface 22a of the first blade B1 is located on the average radial inner side than the radial end surfaces 22a of the other blades B2 to B12.

  This is shown in FIG. FIG. 9 is a cross-sectional view schematically showing the compressor rotor 2 and the eddy current sensor 5. The broken line in the figure indicates the design shape of the blade 22 of the compressor rotor 2. On the other hand, the solid line in the figure shows the actual shape of the blade 22 of the compressor rotor 2. Therefore, the blade 22 shown on the right side of FIG. 9 shows a case where the radial end face 22a is displaced radially inward from the designed shape. In this case, when the blade 22 shown on the right side of FIG. 9 passes in front of the detection unit of the eddy current sensor 5, the maximum value of the output of the eddy current sensor 5 at this time is smaller than the value that should be output originally. Become. That is, the minimum value of the distance between the radial end face 22a of the blade 22 and the eddy current sensor 5 detected by the eddy current sensor 5 when the blade 22 passes is larger than the distance that should be originally detected.

  Therefore, in the present embodiment, the compressor rotates based on the minimum value of the distance between the radial end surface 22a of the blade 22 detected by the eddy current sensor 5 when each blade passes in front of the eddy current sensor 5 and the detection unit. The body shape error is calculated. Specifically, for all the blades 22, if the minimum value of the distance detected by the eddy current sensor 5 is a value within a predetermined range (for example, within a predetermined distance from the design value), the blade It is determined that 22 does not have a large shape error. Conversely, when there is a blade 22 whose minimum distance detected by the eddy current sensor 5 is not within a predetermined range, it is determined that a large shape error exists in the blade 22.

  Alternatively, the average value of the minimum values of the distances detected by the eddy current sensor 5 for all the blades 22 is calculated. When the minimum value of the distance detected by the eddy current sensor 5 for each blade 22 is within a predetermined distance from the calculated average value, there is no large shape error in the blade 22. You may make it determine. In this case, when there is a blade 22 in which the minimum value of the distance detected by the eddy current sensor 5 is not within the predetermined distance from the average value, it is determined that there is a large shape error in the blade 22. Become.

  Thus, according to this embodiment, when each blade 22 passes in front of the detection unit of the eddy current sensor 5, the distance between the radial end surface 22a of the blade 22 and the detection unit of the eddy current sensor 5 is determined as the eddy current. By detecting by the sensor 5 and calculating the shape error of the blade 22 based on the detected distance, the shape error in the radial end face 22a of the blade 22 can be calculated.

<Compressor runout>
By the way, the maximum value of the output of the eddy current sensor 5 when each blade 22 passes in front of the detection part of the eddy current sensor 5 is not necessarily constant even if it is the same blade as shown in FIG. A certain degree of variation occurs. FIG. 10 is a view similar to FIG. 8 showing the transition of the output of the eddy current sensor 5. In the example shown in FIG. 10, for example, the maximum value of the output when the first blade B1 passes in front of the detection unit of the eddy current sensor 5 has a variation of ΔV1 in a plurality of measurements.

  Such variation in the maximum value of the output of the eddy current sensor 5 with respect to the same blade 22, that is, variation in the minimum value of the distance between the detection part of the eddy current sensor 5 and the radial end surface 22 a of the blade 22 is, for example, the shaft 4. And a bearing (not shown) that supports the shaft 4. That is, when the gap between the bearing and the shaft becomes large, the shaft 4 is greatly shaken while the shaft 4 is rotating, and accordingly, the compressor rotor 2 is greatly shaken.

  Therefore, in the present embodiment, the variation in the minimum value of the distance between the detection unit of the eddy current sensor 5 and the radial end surface 22a of the blade 22 when the same blade 22 passes in front of the eddy current sensor 5 a plurality of times. Based on the above, the runout of the compressor rotor is calculated. Then, if the variation in the minimum value of the distance detected by the eddy current sensor 5 a plurality of times by the passage of the specific blade 22 is equal to or smaller than a predetermined upper limit value, it is determined that the clearance in the bearing is not so large. Like to do. On the contrary, when the variation of the minimum value of the distance detected by the eddy current sensor 5 a plurality of times by the passage of the specific blade 22 is larger than a predetermined upper limit value, the clearance in the bearing is not relatively large. I am trying to judge.

<Other embodiments>
As described above, according to the above embodiment, various shape errors of the compressor rotating body 2, shakes of the compressor rotating body, and the like can be calculated based on the output of the eddy current sensor 5. Therefore, when these are expressed together, according to the above embodiment, when the compressor rotator 2 is rotated at a constant angular velocity, the distance between the end surface of each blade passing in front of the sensor and the sensor detection unit or It can be said that the state of the compressor rotor is detected based on the distance detected by the sensor that detects that each blade has passed in front of the sensor or the passage timing of each blade.

  In the present embodiment, the eddy current sensor 5 is disposed in the housing 3. However, the eddy current sensor 5 is not necessarily arranged in the housing 3 when detecting a shape error or the like when manufacturing the compressor rotor 2. Therefore, for example, as indicated by a broken line in FIG. 9, the eddy current sensor 5 ′ may be disposed so as to face the inlet side end face 22 b of the blade 22. Alternatively, unlike the compressor rotator 2 shown in FIGS. 1 and 9, when the compressor rotator 2 has an end face in the axial direction opposite to the inlet side, the eddy current sensor 5 faces the end face. You may arrange as follows. When the eddy current sensor 5 is arranged as shown by a broken line in FIG. 9, it is possible to detect a shape error not at the radial end face 22 a of the blade 22 but at the inlet end face 22 b of the blade 22.

  Moreover, in the said embodiment, the eddy current sensor has detected the state of the compressor rotary body about the compressor of the exhaust gas turbocharger of an internal combustion engine. However, the inspection apparatus can be applied to any compressor as long as it has a compressor rotating body having a plurality of blades. Therefore, for example, it is applicable also to an axial flow type compressor etc.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Compressor rotating body 3 Housing 4 Shaft 5 Eddy current sensor (passage detection sensor)
6 ECU
21 Central body 22 Blade 25 Coil 31 Central passage 32 Annular passage 33 Inlet

Claims (2)

An inspection apparatus for inspecting a compressor rotor having a plurality of blades,
A sensor arranged to face the end face in the radial direction of the blade or the end face in the axial direction, and a detection device for detecting the state of the compressor rotor based on the output of the sensor;
The sensor detects the distance between the end face and the detection portion of the sensor of each blade passing in front of the sensor,
The detection device detects the state of the compressor rotating body based on distance detected by the sensor when the compressor rotational body is rotated at a constant angular speed,
The detection device calculates a shape error of the compressor rotor based on a minimum value of the distance detected by the sensor when each blade passes in front of the sensor;
The detection device calculates a shake of the compressor rotating body based on a variation in the minimum value of the distance detected by the sensor when the same blade passes a plurality of times in front of the sensor . The detection device detects that each blade has passed in front of the sensor, and based on the output of the sensor, a time interval during which at least one pair of the blades passes in front of the sensor The inspection apparatus according to claim 1, wherein a shape error of the compressor rotating body is calculated based on the calculated time interval.

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