JP2017090191A - Rotation sensor for turbo and turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost rotation sensor for turbo that can accurately detect the rotation speed of a turbocharger, and provide the turbocharger.SOLUTION: The rotation sensor for turbo includes: a tabular magnet 2 that is disposed at an end on a turbine 12 side of a compressor wheel 17 so as to rotate with the compressor wheel 17, has a plurality of magnetic poles 2a and 2b having different polarities in a circumferential direction about the rotation axis of the compressor wheel 17, and is formed so that the magnetization direction becomes an axial direction parallel with the rotation axis; and a sensor unit 3 that is disposed in a compressor-side housing 15 so as to face the compressor wheel 17, is disposed so as to face the magnet 2, and can measure the change of the intensity of the magnetic field caused by the magnet 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a turbo rotation sensor and a turbocharger.

  2. Description of the Related Art Conventionally, a turbo rotation sensor that detects the rotation speed of a turbocharger mounted on a vehicle is known that uses an eddy current sensor (see, for example, Patent Document 1).

  In the turbo rotation sensor described in Patent Document 1, a sensor unit composed of an eddy current sensor is disposed in the vicinity of a compressor blade made of aluminum or the like, and the turbocharger is controlled by a change in the voltage of the eddy current sensor based on the rotation of the compressor blade. The rotation speed is detected.

Japanese Patent No. 5645207

  By the way, it can be said that it is not desirable to provide a through-hole for providing a sensor portion in the housing of the turbocharger in order to suppress the turbulence of the air flow in the compressor of the turbocharger. When the through hole is provided in the housing, it is necessary to provide a seal mechanism around the sensor unit, which causes a problem that the cost is increased.

  However, when an eddy current sensor is used as in Patent Document 1, since the housing is made of a conductor such as aluminum, the sensor portion and the compressor blades are connected to each other through the housing without forming a through hole in the housing. When facing each other, there is a problem that the rotational speed of the turbocharger may not be detected accurately due to the influence of the eddy current generated in the housing.

  In addition, the eddy current sensor requires a signal processing circuit such as a resonance circuit because the change in magnetic flux is small, and there is a problem that the cost is high.

  Therefore, an object of the present invention is to provide a turbo rotation sensor and a turbocharger that can detect the rotation speed of the turbocharger with high accuracy and are low in cost.

  In order to solve the above problems, the present invention provides a turbine having a turbine wheel that is provided in an exhaust passage of an internal combustion engine of a vehicle and is driven to rotate by exhaust from the internal combustion engine, and an intake passage of the internal combustion engine. A turbo rotation sensor that is mounted on a turbocharger that detects a rotational speed of the compressor wheel, and is provided in a turbocharger having a compressor wheel that is driven to rotate by rotation of the turbine wheel. A plurality of magnetic poles having different polarities are formed in a circumferential direction around the rotation axis of the compressor wheel, and the magnetization direction is different from that of the rotation axis. A plate-like magnet formed so as to be parallel in the axial direction; Provided is a turbo rotation sensor, comprising: a sensor unit provided on a housing of a lesser so as to face the compressor wheel; and a sensor unit provided so as to face the magnet and capable of measuring a change in magnetic field strength by the magnet. To do.

  In order to solve the above-described problems, the present invention provides a turbine having a turbine wheel provided in an exhaust passage of an internal combustion engine of a vehicle and driven to rotate by exhaust from the internal combustion engine, and an intake air of the internal combustion engine A turbocharger provided in a passage and having a compressor wheel that is rotationally driven by the rotation of the turbine wheel, wherein a turbo rotation sensor that detects a rotational speed of the compressor wheel is mounted; The rotation sensor for rotation is provided at an end of the compressor wheel on the turbine side so as to rotate together with the compressor wheel, and a plurality of magnetic poles having different polarities are formed in a circumferential direction around the rotation axis of the compressor wheel. In addition, the magnetization direction is an axial direction parallel to the rotation axis. A plate-shaped magnet formed, and a sensor unit that is provided to face the compressor wheel in the housing of the compressor, and that is provided to face the magnet, and capable of measuring a change in magnetic field strength by the magnet; Provide a turbocharger with

  According to the present invention, it is possible to provide a turbo rotation sensor and a turbocharger that can detect the rotation speed of a turbocharger with high accuracy and are low in cost.

It is a schematic block diagram of the turbocharger carrying the turbo rotation sensor which concerns on one embodiment of this invention. (A) is a perspective view of a compressor wheel and a magnet, (b) is the side view and back view. It is a perspective view of a magnet. It is a perspective view which shows one modification of a magnet. It is a figure which shows an example of a sensor part, (a) is a fracture surface figure, (b) is a schematic block diagram.

[Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(Description of turbocharger)
FIG. 1 is a schematic configuration diagram of a turbocharger equipped with a turbo rotation sensor according to the present embodiment.

  As shown in FIG. 1, the turbocharger 10 includes a compressor 11 provided in an intake passage 13 of an internal combustion engine (not shown) of a vehicle, and a turbine 12 provided in an exhaust passage 14 of the internal combustion engine.

  The compressor 11 is configured by housing a compressor wheel 17 having a plurality of compressor blades 16 in a compressor-side housing 15. The turbine 12 is configured by accommodating a turbine wheel 20 having a plurality of turbine blades 19 in a turbine-side housing 18. The turbine 12 is configured to receive exhaust from the internal combustion engine with the turbine blades 19 and to drive the turbine wheel 20 to rotate.

  The compressor wheel 17 and the turbine wheel 20 are connected by a turbo shaft 21, and the compressor wheel 17 is configured to be rotationally driven by the rotation of the turbine wheel 20. As a result, the turbocharger 10 is configured so that the compressor wheel 17 is rotationally driven in accordance with the rotation of the turbine wheel 20 that is rotationally driven by exhaust from the internal combustion engine, thereby compressing the intake air and feeding it to the internal combustion engine. ing.

  The turbo shaft 21 is rotatably supported by a bearing housing 22 that connects the compressor side housing 15 and the turbine side housing 18. An oil passage 23 to which lubricating oil for lubricating and cooling the turboshaft 21 is supplied is formed in the bearing housing 22, and the heat on the turbine 12 side is caused by a cooling effect by the lubricating oil supplied to the oil passage 23. Is transmitted to the compressor 11 side.

  In the present embodiment, the compressor side housing 15 and the compressor wheel 17 including the compressor blades 16 are made of aluminum (or aluminum alloy). The compressor wheel 17 may be made of a nonmagnetic material such as resin.

  As shown in FIG. 2A, the compressor wheel 17 is a side surface that is curved so that its diameter gradually increases from the front end side (intake side of intake, upper side in the figure) to the base end side (turbine side, lower side in the figure). A plurality of compressor blades 16 are integrally formed on the side surface of the base body 17a having a slant with respect to the axial direction. A through hole 17b into which the turbo shaft 21 is inserted and connected is formed at the center of the base body 17a. The base body 17a has a substantially disc-shaped base end portion 17c extending from the compressor blade 16 to the base end side (turbine side).

(Explanation of turbo rotation sensor)
The turbocharger 10 is equipped with a turbo rotation sensor 1 that detects the rotation speed of the turbocharger 10, that is, the rotation speed of the compressor wheel 17.

  As shown in FIGS. 1 to 3, the turbo rotation sensor 1 includes a plate-like magnet 2 provided to rotate with the compressor wheel 17 at an end of the compressor wheel 17 on the turbine 12 side (turbine wheel 20 side). And a sensor unit 3 capable of measuring a change in the magnetic field strength by the magnet 2 (change in the magnetic field strength accompanying the rotation of the magnet 2).

  The magnet 2 is in contact with and fixed to the end surface of the base end portion 17 c of the base body 17 a in the compressor wheel 17. The magnet 2 has a plurality of magnetic poles 2a and 2b having different polarities in the circumferential direction around the rotation axis of the compressor wheel 17 (the central axis of the turbo shaft 21), and the magnetization direction (magnetization direction) is the rotation axis. It is formed so that it may become an axial direction parallel to.

  In the present embodiment, a magnet 2 that is formed in a disk shape and has two poles (N pole 2a and S pole 2b) in the circumferential direction is used. An insertion hole 2 c for inserting the turbo shaft 21 is formed at the center of the magnet 2.

  By setting the magnetization direction of the magnet 2 along the axial direction, the magnetic flux emitted from the magnet 2 in the axial direction increases, and the magnetic flux can reach the position away from the magnet 2 in the axial direction. Thus, even if the distance between the magnet 2 and the sensor unit 3 is increased, the sensor unit 3 can measure the change in the strength of the magnetic field by the magnet 2 with high accuracy. The magnetization direction of the magnet 2 is allowed even if it is slightly deviated (for example, about ± 10 °) from the axial direction.

  Further, by arranging the magnet 2 at the end (end surface) of the compressor wheel 17 on the turbine 12 side, the area (volume) of the magnet 2 is increased, and the magnetic flux emitted from the magnet 2 in the axial direction is increased. Can be made. In the turbocharger 10, since the intake air is supplied from the front end side (the side opposite to the turbine 12) of the compressor wheel 17, the magnet 2 hardly affects the intake air, and the turbocharger can be used even when the size of the magnet 2 is increased. 10 performance degradation can be suppressed.

  Although it is conceivable to provide a magnet on the front end side (opposite side of the turbine 12) of the compressor wheel 17, in that case, it is necessary to make the magnet small so as not to increase the intake resistance, and at a position away from the magnet. It becomes difficult to detect a change in the strength of the magnetic field. For this reason, it is necessary to take measures such as forming a through-hole in the compressor-side housing 15 so that the sensor unit 3 protrudes into the intake passage, and the performance of the turbocharger 10 due to the influence of intake air is reduced. There is a possibility that problems such as an increase in

  Thus, in the present embodiment, the magnetization direction of the magnet 2 is the direction along the axial direction, and the magnet 2 is arranged at the end of the compressor wheel 17 on the turbine 12 side so that the area (volume) of the magnet 2 is increased. As a result, the magnetic flux reaching the position away from the magnet 2 in the axial direction is increased, and the sensor unit 3 can be arranged at a position away from the magnet 2 in the axial direction. Accordingly, the sensor unit 3 can detect the strength of the magnetic field generated by the magnet 2 via the compressor-side housing 15, and it is not necessary to form a through hole in the compressor-side housing 15.

  Further, in the present embodiment, the magnet 2 having two poles 2a and 2b formed in the circumferential direction is used. Thereby, compared with the case where the magnetic poles 2a and 2b of 4 or more poles are formed, for example, it becomes possible to reach the magnetic flux to a position further away from the magnet 2 in the axial direction.

  Further, by using the magnet 2 in which the two magnetic poles 2a and 2b are formed, the measurement frequency in the sensor unit 3 can be minimized. Since the maximum rotation speed of the compressor wheel 17 in the turbocharger 10 is generally about 200,000 to 400,000 rpm, the measurement frequency in the present embodiment is about 7,000 Hz (400,000 / 60) at the maximum. For example, in the electromagnetic pickup type sensor unit 3, measurement at a measurement frequency of about 20,000 Hz or more is generally difficult due to the influence of eddy current loss, but in this embodiment, the measurement frequency is The detection is sufficiently low and detection using the electromagnetic pickup type sensor unit 3 is possible. In the conventional eddy current method, since all the compressor blades 16 are detected, the measurement frequency becomes very high.

  As the magnet 2, it is desirable to use a magnet that is not easily cracked or chipped and that can be thinly formed to avoid an increase in weight. In the present embodiment, an Fe—Cr—Co magnet is used as the magnet 2. The Fe—Cr—Co magnet formed by rolling can be thinned to a thickness of about 0.2 mm. In order to suppress the deterioration of the performance of the turbocharger 10 such as a turbo lag due to the influence of the weight increase due to the provision of the magnet 2, the thickness of the magnet 2 is desirably 0.5 mm or less. The Fe—Cr—Co magnet has a small demagnetization due to temperature, and is suitable as the magnet 2 used in a high temperature environment as in the present embodiment.

  The outer diameter and inner diameter of the magnet 2 are not particularly limited, but the magnet 2 projects at least radially outward from the compressor wheel 17 in order to prevent the magnet 2 from affecting the intake air. It is desirable not to be provided. The outer diameter and inner diameter of the magnet 2 can suppress the performance deterioration of the turbocharger 10 in consideration of the position of the sensor unit 3 (distance from the magnet 2), the weight of the magnet 2, and the like. The intensity may be adjusted as appropriate so that the intensity can be sufficiently detected. In addition, although mentioned later for details, it is desirable that the magnet 2 is provided in the position facing the front-end | tip part of the sensor part 3 in an axial direction.

  The magnet 2 is attached to the end of the compressor wheel 17 on the turbine 12 side (end surface of the base end portion 17c) by an appropriate fixing method such as adhesive fixing using an adhesive, bolt fixing (screw fixing), or press fitting. Can be fixed.

  The magnet 2 does not need to be directly fixed to the compressor wheel 17 and may be fixed to the turbo shaft 21. For example, as shown in FIG. 4, a hollow cylindrical fixing portion 2 d in which a thread groove (not shown) is formed on the inner peripheral surface of the magnet 2 is integrally formed, and the fixing portion 2 d is formed on the outer peripheral surface of the turbo shaft 21. You may comprise so that it may be screwed and fixed to the formed screw thread. In this case, as the magnet 2, a magnet that can be molded by casting is preferably used. For example, an Fe—Cr—Co magnet or an Alnico (Al—Ni—Co) magnet can be used.

  The sensor unit 3 is provided in the compressor side housing 15 so as to face the compressor wheel 17 and is provided so as to face the magnet 2. In the present embodiment, the sensor unit 3 is configured such that a tip portion thereof (a sensing portion, here, a tip portion of a magnetic path forming member 32 described later) faces the magnet 2 in the axial direction. In other words, the tip of the sensor unit 3 is arranged inside the outer edge of the magnet 2 and outside the inner edge in the radial direction.

  In the present embodiment, the sensor unit 3 is an electromagnetic pickup type (magnetic pickup type). As shown in FIGS. 5 (a) and 5 (b), the sensor unit 3 includes a rod-shaped magnetic path forming member (pole piece) 32 such as an iron core through which the magnetic flux from the magnet 2 passes, and the periphery of the magnetic path forming member 32. And a voltage detector 34 that measures the induced electromotive force generated in the coil 33.

  The magnetic path forming member 32 and the coil 33 are accommodated in a sensor housing 35 having a flange portion 35 a for fixing to the compressor side housing 15, and are provided at an end portion of a cable 36 extending from the sensor housing 35. The connector 37 is connected to the voltage detector 34 (not shown in FIG. 5A). In addition, the structure of the sensor part 3 shown to Fig.5 (a), (b) is an example to the last, and the specific structure of the sensor part 3 is not limited to this.

  When the N pole 2a or S pole 2b of the magnet 2 approaches or separates from the tip of the magnetic path forming member 32, the magnetic field in the coil 33 changes, and an induced electromotive force is generated at both ends of the coil 33. Therefore, it is possible to detect the rotation speed of the magnet 2, that is, the rotation speed of the compressor wheel 17 by detecting the change of the induced electromotive force by the voltage detection unit 34.

  The electromagnetic pickup type sensor unit 3 does not require a power supply and does not require a resonance circuit or the like. Therefore, the electromagnetic pickup type sensor unit 3 has a simple configuration and a very low cost as compared with a conventionally used eddy current sensor. However, the present invention is not limited to this, and the sensor unit 3 may be one using a magnetic detection element such as a Hall IC or a GMR (Giant Magneto Resistive effect) sensor.

  Returning to FIG. 1, the sensor unit 3 is attached to the compressor-side housing 15. In the present embodiment, the sensor unit 3 is accommodated in a sensor hole 15 a formed on the outer surface of the compressor side housing 15 so as not to penetrate the compressor side housing 15. The sensor unit 3 is disposed in the sensor hole 15a so that the tip of the magnetic path forming member 32 faces the compressor wheel 17 and faces the magnet 2 in the axial direction.

  In a conventional eddy current sensor, measurement is difficult unless a through-hole is formed in the compressor-side housing 15, but in the present embodiment, a change in the strength of the magnetic field accompanying the rotation of the magnet 2 is detected by the sensor unit. 3, even if the sensor unit 3 and the magnet 2 are opposed to each other via the compressor-side housing 15, the rotational speed of the turbocharger 10 is accurately affected without being affected by the compressor-side housing 15. Can be detected.

  In the present embodiment, it is not necessary to form a through hole in the compressor-side housing 15 in order to arrange the sensor unit 3, and therefore it is possible to suppress the disturbance of the intake airflow due to the formation of the through hole, Further, since it is not necessary to provide a seal mechanism around the sensor unit 3, the cost is low.

  Further, in the present embodiment, the sensor unit 3 is disposed at a position farther from the turbine 12 than the base end portion (end portion on the turbine 12 side) of the compressor wheel 17. As a result, the sensor unit 3 is disposed at a position away from the turbine 12 that becomes high temperature due to exhaust, and the sensor unit 3 is less susceptible to the heat of the turbine 12.

  In the present embodiment, since the magnetic flux emitted from the magnet 2 in the axial direction is increased, even if the sensor unit 3 is arranged at a certain distance from the magnet 2, the magnet in the sensor unit 3 It is possible to detect a change in the strength of the magnetic field due to 2. However, in order to further improve the detection accuracy, it can be said that the distance along the axial direction between the sensor unit 3 and the magnet 2 is desirably as small as possible. In the present embodiment, the sensor unit 3 is arranged so as to face the end of the compressor blade 16 on the turbine 12 side (portion expanded in the radial direction), so that the axial direction of the sensor unit 3 and the magnet 2 is increased. The distance along the line is configured to be as small as possible.

(Operation and effect of the embodiment)
As described above, in the turbo rotation sensor 1 according to the present embodiment, a plurality of magnetic poles provided at the end of the compressor wheel 17 on the turbine 12 side so as to rotate together with the compressor wheel 17 and having different polarities in the circumferential direction. 2a and 2b are formed, the plate-like magnet 2 is formed so that the magnetization direction is an axial direction parallel to the rotation axis, and the compressor-side housing 15 is provided so as to face the compressor wheel 17, and the magnet 2, and a sensor unit 3 that can measure a change in the strength of the magnetic field by the magnet 2.

  With this configuration, even when the sensor unit 3 is arranged at a position away from the magnet 2, the sensor unit 3 can accurately detect a change in the strength of the magnetic field accompanying the rotation of the magnet 2, and the compressor The rotational speed of the turbocharger 10 can be accurately detected without forming a through hole in the side housing 15.

  Further, as the sensor unit 3, it is possible to use an electromagnetic pickup type that is less expensive than the conventionally used eddy current sensor, and it is not necessary to provide a seal mechanism around the sensor unit 3. Cost can be reduced. That is, according to the present embodiment, it is possible to detect the rotational speed of the turbocharger 10 with high accuracy and to realize a low-cost turbo rotation sensor 1.

(Summary of embodiment)
Next, the technical idea grasped from the embodiment described above will be described with reference to the reference numerals in the embodiment. However, the reference numerals and the like in the following description are not intended to limit the constituent elements in the claims to the members and the like specifically shown in the embodiments.

[1] A turbine (12) having a turbine wheel (20) provided in an exhaust passage (14) of an internal combustion engine of a vehicle and driven to rotate by exhaust from the internal combustion engine, and an intake passage (13) of the internal combustion engine And a compressor (11) having a compressor wheel (17) that is rotationally driven by the rotation of the turbine wheel (17), and is mounted on a turbocharger (10), the rotation of the compressor wheel (17) A turbo rotation sensor (1) for detecting a speed, provided at an end of the compressor wheel (17) on the turbine (12) side so as to rotate together with the compressor wheel (17). 17) When a plurality of magnetic poles (2a, 2b) having different polarities are formed in the circumferential direction around the rotation axis Further, a plate-like magnet (2) formed so that the magnetization direction is an axial direction parallel to the rotation axis, and the housing (15) of the compressor (11) so as to face the compressor wheel (17). A turbo rotation sensor (1) provided with a sensor unit (3) provided so as to face the magnet (2) and capable of measuring a change in intensity of a magnetic field by the magnet (2).

[2] The turbo according to [1], wherein the sensor unit (3) is accommodated in a sensor hole (15a) formed so as not to penetrate the housing (15) on an outer surface of the housing (15). Rotation sensor (1).

[3] The turbo rotation sensor (1) according to [1] or [2], wherein the tip of the sensor unit (3) is configured to face the magnet (2) in the axial direction.

[4] Any one of [1] to [3], wherein the magnet (2) is formed in a disk shape and is formed by forming two magnetic poles (2a, 2b) in the circumferential direction. The turbo rotation sensor (1) described in 1.

[5] The turbo rotation sensor (1) according to any one of [1] to [4], wherein the magnet (2) is made of a Fe—Cr—Co magnet.

[6] The turbo rotation sensor (1) according to [5], wherein the magnet (6) has a thickness of 0.5 mm or less.

[7] A turbine (12) having a turbine wheel (20) provided in an exhaust passage (14) of an internal combustion engine of a vehicle and driven to rotate by exhaust from the internal combustion engine, and an intake passage (13) of the internal combustion engine And a compressor (11) having a compressor wheel (17) that is rotationally driven by the rotation of the turbine wheel (17), the turbocharger (10) having a rotation of the compressor wheel (17) A turbo rotation sensor (1) for detecting the speed is mounted, and the turbo rotation sensor (1) rotates with the compressor wheel (17) at the end of the compressor wheel (17) on the turbine (12) side. A plurality of different polarities in the circumferential direction around the rotation axis of the compressor wheel (17). A pole (2a, 2b) is formed, and a plate-like magnet (2) formed so that the magnetization direction is an axial direction parallel to the rotation axis, and a housing (15) of the compressor (11) A sensor unit (3) provided so as to face the compressor wheel (17) and facing the magnet (2) and capable of measuring a change in magnetic field intensity by the magnet (2). Turbocharger (10).

[8] The sensor unit (3) according to [7], wherein the sensor unit (3) is disposed at a position farther from the turbine (12) than an end of the compressor wheel (17) on the turbine (12) side. Turbocharger (10).

[9] The sensor section (3) is accommodated in a sensor hole (15a) formed on the outer surface of the housing (15) so as not to penetrate the housing (15), [7] or [8] The turbocharger as described in (10).

[10] The turbocharger according to any one of [7] to [9], wherein a tip portion of the sensor unit (3) is configured to face the magnet (2) in the axial direction. 10).

[11] Any one of [7] to [10], wherein the magnet (2) is formed in a disc shape and is formed by forming two magnetic poles (2a, 2b) in the circumferential direction. The turbocharger as described in (10).

[12] The turbocharger (10) according to any one of [7] to [11], wherein the magnet (2) is made of an Fe—Cr—Co magnet.

[13] The turbocharger (10) according to [12], wherein the magnet (2) has a thickness of 0.5 mm or less.

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

  The present invention can be appropriately modified and implemented without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Turbo rotation sensor 2 ... Magnet 2a ... N pole (magnetic pole)
2b ... S pole (magnetic pole)
DESCRIPTION OF SYMBOLS 3 ... Sensor part 10 ... Turbocharger 11 ... Compressor 12 ... Turbine 13 ... Intake passage 14 ... Exhaust passage 15 ... Compressor side housing (housing)
15a ... Sensor hole 17 ... Compressor wheel 20 ... Turbine wheel

Claims (13)

A turbine provided in an exhaust passage of an internal combustion engine of a vehicle and having a turbine wheel that is rotationally driven by exhaust from the internal combustion engine, and a compressor provided in an intake passage of the internal combustion engine and rotationally driven by the rotation of the turbine wheel A turbo rotation sensor that is mounted on a turbocharger that includes a wheel and detects the rotation speed of the compressor wheel,
A plurality of magnetic poles having different polarities are formed in a circumferential direction around the rotation axis of the compressor wheel, and the magnetization direction is provided at an end of the compressor wheel on the turbine side so as to rotate together with the compressor wheel. A plate-like magnet formed so as to be in an axial direction parallel to the rotation axis;
A sensor unit provided on the compressor housing so as to face the compressor wheel, and facing the magnet, and capable of measuring a change in the strength of the magnetic field by the magnet.
Turbo rotation sensor. The sensor part is accommodated in a sensor hole formed on the outer surface of the housing so as not to penetrate the housing.
The turbo rotation sensor according to claim 1. The tip of the sensor unit is configured to face the magnet in the axial direction.
The turbo rotation sensor according to claim 1 or 2. The magnet is formed in a disk shape, and is configured by forming two magnetic poles in the circumferential direction.
The turbo rotation sensor according to any one of claims 1 to 3. The magnet is made of a Fe-Cr-Co magnet.
The turbo rotation sensor according to any one of claims 1 to 4. The magnet has a thickness of 0.5 mm or less,
The turbo rotation sensor according to claim 5. A turbine provided in an exhaust passage of an internal combustion engine of a vehicle and having a turbine wheel that is rotationally driven by exhaust from the internal combustion engine, and a compressor provided in an intake passage of the internal combustion engine and rotationally driven by the rotation of the turbine wheel A turbocharger comprising a compressor having a wheel,
A turbo rotation sensor that detects the rotation speed of the compressor wheel is mounted,
The turbo rotation sensor is
A plurality of magnetic poles having different polarities are formed in a circumferential direction around the rotation axis of the compressor wheel, and the magnetization direction is provided at an end of the compressor wheel on the turbine side so as to rotate together with the compressor wheel. A plate-like magnet formed so as to be in an axial direction parallel to the rotation axis;
A sensor unit provided on the compressor housing so as to face the compressor wheel, and facing the magnet, and capable of measuring a change in the strength of the magnetic field by the magnet.
Turbocharger. The sensor unit is disposed at a position farther from the turbine than an end of the compressor wheel on the turbine side.
The turbocharger according to claim 7. The sensor part is accommodated in a sensor hole formed on the outer surface of the housing so as not to penetrate the housing.
The turbocharger according to claim 7 or 8. The tip of the sensor unit is configured to face the magnet in the axial direction.
The turbocharger according to any one of claims 7 to 9. The magnet is formed in a disk shape, and is configured by forming two magnetic poles in the circumferential direction.
The turbocharger according to any one of claims 7 to 10. The magnet is made of a Fe-Cr-Co magnet.
The turbocharger according to any one of claims 7 to 11. The magnet has a thickness of 0.5 mm or less,
The turbocharger according to claim 12.

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