JP6690865B2 - Rotary actuator and VG actuator - Google Patents

Description

  The present invention relates to a rotary actuator and a VG (Variable Geometry) actuator using the rotary actuator.

  Conventionally, VG turbochargers for automobiles have been developed. Further, an actuator for controlling the opening of the nozzle vane in a VG turbocharger, a so-called "VG actuator" has been developed. An electronically controlled rotary actuator is used as the VG actuator.

  The VG actuator is provided with a mechanism that detects the rotation angle of the shaft using a magnet and a sensor. That is, the magnet is provided at one end of the shaft and is rotatable integrally with the shaft. The sensor is arranged to face the magnet via a so-called "air gap". The sensor detects the rotation angle of the shaft by detecting the magnetic field generated by the magnet (see, for example, Patent Document 1).

International Publication No. 2014/029885

  Usually, the range of the value of the magnetic flux density that can be detected by the sensor (hereinafter referred to as "detectable range") is set to a predetermined range according to the specifications of the sensor. Therefore, in the mechanism that detects the rotation angle of the shaft, it is required that the value of the magnetic flux density at the position of the sensor is within the detectable range. However, since the magnetic flux density at the position of the sensor fluctuates due to the following factors, it was difficult to keep the value of the magnetic flux density within the detectable range.

  First, the VG actuator is composed of a plurality of parts, and has a margin in the design size of each part from the viewpoint of absorbing the dimensional variation of each part. Therefore, the VG actuator has rattling between parts, and the width of the air gap fluctuates due to the rattling. The magnetic flux density at the sensor position increases as a quadratic function as the width of the air gap decreases. Here, in order to reduce rattling and reduce the amount of variation in the width of the air gap, it is conceivable to improve the dimensional accuracy of each component. However, in this case, there is a problem that the unit price of each component increases and the unit price of the VG actuator also increases.

  Secondly, the magnetic flux density of the magnetic field generated by the magnet changes depending on the environmental temperature. Therefore, the magnetic flux density at the position of the sensor also changes according to the environmental temperature. Therefore, even if the variation in the width of the air gap is reduced by increasing the dimensional accuracy of each component, it is difficult to keep the value of the magnetic flux density at the sensor position within the detectable range.

  The present invention has been made to solve the above problems, and it is an object of the present invention to provide a rotary actuator and a VG actuator in which the value of the magnetic flux density at the position of the sensor can be easily set within the detectable range. To aim.

The rotary actuator of the present invention is provided at one end of a shaft, is arranged so as to be rotatable integrally with the shaft, and is arranged to face the magnet via an air gap, and detects a magnetic field generated by the magnet. And a sensor for detecting the rotation angle of the shaft by means of the first magnet, and the magnet is composed of a first half part corresponding to the N pole and a second half part corresponding to the S pole. A hole or a magnetic shield body is provided between the second halves, and the sensor detects a magnetic field straddling the hole or the magnetic shield body. The magnet is provided with a hole, and the hole is composed of a recess formed in a surface of the magnet facing the sensor.

  According to the present invention, since it is configured as described above, it is possible to obtain a rotary actuator and a VG actuator in which the value of the magnetic flux density at the position of the sensor can be easily set within the detectable range.

It is explanatory drawing which shows the principal part of the rotary actuator which concerns on Embodiment 1 of this invention. FIG. 3 is a plan view of the magnet according to Embodiment 1 of the present invention. It is sectional drawing which follows the A-A 'line shown in FIG. It is explanatory drawing which shows the distribution of the magnetic flux density by the magnetic field which arose between the central part of a 1st half part, and the central part of a 2nd half part when using the magnet which does not have a hole part. It is explanatory drawing which shows the distribution of the magnetic flux density by the magnetic field produced between the central part of a 1st half part, and the central part of a 2nd half part, when using the magnet which has a hole part. Characteristic showing the magnetic flux density at the position of the sensor due to the magnetic field generated between the central portion of the first half portion and the central portion of the second half portion with respect to the width of the air gap when a magnet without holes is used. It is a figure. A characteristic diagram showing the magnetic flux density at the position of the sensor due to the magnetic field generated between the central portion of the first half portion and the central portion of the second half portion with respect to the width of the air gap when a magnet having holes is used. Is. FIG. 6 is a plan view of another magnet according to the first embodiment of the present invention. FIG. 9 is a cross-sectional view taken along the line A-A ′ shown in FIG. 8. FIG. 6 is a plan view of another magnet according to the first embodiment of the present invention. FIG. 11 is a cross-sectional view taken along the line A-A ′ shown in FIG. 10. FIG. 6 is a plan view of another magnet according to the first embodiment of the present invention. FIG. 13 is a cross-sectional view taken along the line A-A ′ shown in FIG. 12.

  Hereinafter, in order to describe the present invention in more detail, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1.
FIG. 1 is an explanatory diagram showing a main part of a rotary actuator according to a first embodiment of the present invention. FIG. 2 is a plan view of the magnet according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line AA ′ shown in FIG. With reference to FIGS. 1 to 3, the rotary actuator 100 according to the first embodiment will be described focusing on an example applied to a vehicle-mounted VG actuator.

  In the figure, 1 is a gear. The gear 1 is adapted to rotate by driving a motor (not shown). A substantially rod-shaped shaft 2 is provided along the rotation axis A1. That is, the gear 1 is provided at one end of the shaft 2, and the output lever 3 is provided at the other end of the shaft 2. The shaft 2 rotates integrally with the gear 1 (see the arrow A2 shown in FIG. 1), and the output lever 3 rotates when the shaft 2 rotates. The rotation of the output lever 3 changes the opening of a nozzle vane provided in a VG turbocharger (not shown).

  A magnet 4 having a substantially disk shape is provided at one end of the shaft 2. The magnet 4 is rotatable integrally with the shaft 2 and has a substantially semi-disc shaped portion corresponding to the N pole (hereinafter referred to as "first half portion") 4N and a substantially semi-disc shaped portion corresponding to the S pole (hereinafter It is referred to as the "second half") 4S. A hole 42 is provided between the central portion 41N of the first half portion 4N and the central portion 41S of the second half portion 4S. That is, the hole 42 is arranged at the center of the magnet 4, and is arranged on the rotation axis A1. As shown in FIGS. 2 and 3, the hole 42 is formed of a substantially cylindrical through hole extending along the rotation axis A1.

  In the figure, 5 is a sensor. The sensor 5 is mounted on the electronic circuit board 6 and is arranged so as to face the magnet 4 via the air gap 7. The sensor 5 detects the rotation angle of the shaft 2 by detecting the component of the magnetic field generated by the magnet 4 in the direction along the detection surface 51 (see arrow A3 shown in FIG. 1). That is, the sensor 5 is composed of a rotation angle sensor using a magnetic sensor.

  Here, the sensor 5 is arranged on the rotation axis A1. The sensor 5 detects at least the magnetic field generated between the central portion 41N of the first half portion 4N and the central portion 41S of the second half portion 4S, that is, the magnetic field across the hole portion 42.

  Components such as the gear 1, the shaft 2, the magnet 4, the sensor 5, and the electronic circuit board 6 are housed in a housing (not shown). Here, the member 8 formed by integrally assembling parts such as the gear 1, the shaft 2, the output lever 3, and the magnet 4 has rattling in the direction along the rotation axis A1 with respect to the housing. This rattling occurs because the design dimensions of each of these components have a margin from the viewpoint of absorbing the dimensional variation of each of these components. Due to the rattling of the member 8 with respect to the housing, the width W of the air gap 7 varies.

  In this way, the main part of the rotary actuator 100 is configured.

  Next, with reference to FIGS. 4 to 7, the effect of providing the hole 42 in the magnet 4 will be described.

  FIG. 4 shows a distribution of magnetic flux density due to a magnetic field generated between the central portion 41N of the first half portion 4N and the central portion 41S of the second half portion 4S when the magnet 4 having no hole portion 42 is used. FIG. FIG. 5 shows a magnetic field generated between the central portion 41N of the first half portion 4N and the central portion 41S of the second half portion 4S when the magnet 4 having the hole portion 42 is used, that is, across the hole portion 42. It is explanatory drawing which shows the distribution of the magnetic flux density by a magnetic field.

  In each of FIG. 4 and FIG. 5, the thickness of the broken line and the shading of the color represent the magnitude of the magnetic flux density. As shown in FIGS. 4 and 5, by using the magnet 4 having the hole 42, the magnitude of the magnetic flux density in the vicinity of the center of the magnet 4 is larger than that in the case where the magnet 4 having no hole 42 is used. Can be made smaller.

  FIG. 6 shows that between the central portion 41N of the first half portion 4N and the central portion 41S of the second half portion 4S with respect to the width W of the air gap 7 when the magnet 4 having no hole portion 42 is used. It is a characteristic view which shows the magnetic flux density B in the position of the sensor 5 by the generated magnetic field. FIG. 7 is generated between the central portion 41N of the first half portion 4N and the central portion 41S of the second half portion 4S with respect to the width W of the air gap 7 when the magnet 4 having the hole portion 42 is used. It is a characteristic view which shows the magnetic flux density B in the position of the sensor 5 by a magnetic field, ie, the magnetic field straddling the hole 42.

  In each of FIG. 6 and FIG. 7, ΔW represents a range in which the width W varies due to rattling of the member 8, and ΔB represents a range of values of the magnetic flux density B detectable by the sensor 5, that is, a detectable range. And A4 indicates a region defined by ΔW × ΔB. I indicates a characteristic line when the environmental temperature is approximately -40 ° C, II indicates a characteristic line when the environmental temperature is approximately 150 ° C, and III indicates an environmental temperature of approximately 25 ° C. A characteristic line at a certain time is shown.

  That is, in the range where the characteristic line I is included in the area A4, the sensor 5 can normally detect the rotation angle of the shaft 2 in a temperature environment of approximately -40 ° C. In the range where the characteristic line II is included in the area A4, the sensor 5 can normally detect the rotation angle of the shaft 2 in a temperature environment of approximately 150 ° C. In the range in which the characteristic line III is included in the area A4, the sensor 5 can normally detect the rotation angle of the shaft 2 in a temperature environment of approximately 25 ° C.

  When the magnet 4 having no hole 42 is used, the magnetic flux density in the vicinity of the center of the magnet 4 becomes large (see FIG. 4). Therefore, when the width W of the air gap 7 is small, the magnetic flux density B at the position of the sensor 5 becomes a value larger than the upper limit value of the detectable range ΔB (see the area A5 shown in FIG. 6). As a result, the characteristic lines I to III deviate from the area A4, and the sensor 5 cannot normally detect the rotation angle of the shaft 2.

  In the example shown in FIG. 6, when the environmental temperature is approximately −40 ° C. and the width W of the air gap 7 is less than approximately 1.9 millimeters (mm), the magnetic flux density B is higher than the upper limit value of the detectable range ΔB. Is also a large value. When the environmental temperature is approximately 150 ° C. and the width W of the air gap 7 is less than approximately 1.2 mm, the magnetic flux density B becomes a value larger than the upper limit value of the detectable range ΔB. When the environmental temperature is approximately 25 ° C. and the width W of the air gap 7 is less than approximately 1.7 mm, the magnetic flux density B becomes a value larger than the upper limit value of the detectable range ΔB.

  On the other hand, by using the magnet 4 having the hole 42, the magnitude of the magnetic flux density in the vicinity of the center of the magnet 4 can be reduced (see FIG. 5). This makes it possible to moderate the increase in the magnetic flux density B with respect to the decrease in the width W, as compared with the case where the magnet 4 having no hole 42 is used (see FIGS. 6 and 7). As a result, the value of the magnetic flux density B at the position of the sensor 5 can be kept within the detectable range ΔB regardless of the width W of the air gap 7 and the ambient temperature (see FIG. 7).

  That is, by using the magnet 4 having the hole 42, it becomes easy to keep the value of the magnetic flux density B at the position of the sensor 5 within the detectable range ΔB. Further, since it is not necessary to increase the dimensional accuracy of each component, it is possible to prevent an increase in the unit price of each component and prevent an increase in the unit price of the rotary actuator 100. Further, since the sensor 5 can detect the rotation angle of the shaft 2 even if the width W of the air gap 7 is reduced, the rotary actuator 100 can be downsized.

  The shape of the hole 42 is not limited to the through hole shown in FIGS. 2 and 3. The hole 42 may be at least formed in the surface of the magnet 4 facing the sensor 5.

  Specifically, for example, as shown in FIGS. 8 and 9, the hole 42 may be formed by a substantially hemispherical recess formed in the surface of the magnet 4 facing the sensor 5. Thereby, as in the example shown in FIG. 5, the magnitude of the magnetic flux density in the vicinity of the center of the magnet 4 can be reduced. As a result, the same effect as in the case where the magnet 4 is provided with the through hole can be obtained.

  Alternatively, for example, as shown in FIG. 10 and FIG. 11, the hole 42 and a substantially hemispherical concave portion (hereinafter referred to as “first concave portion”) 42 a formed in a surface of the magnet 4 facing the sensor 5 and the facing portion. It may be configured by a substantially hemispherical concave portion (hereinafter referred to as “second concave portion”) 42b formed on the rear surface portion with respect to the surface portion. Thereby, as in the example shown in FIG. 5, the magnitude of the magnetic flux density in the vicinity of the center of the magnet 4 can be reduced. As a result, it is possible to obtain the same effect as in the case where the through hole is provided in the magnet 4 or the case where the concave portion is provided only in the facing surface portion with respect to the sensor 5. Further, since the shape of the half of the magnet 4 on the facing surface side and the shape of the half on the back surface side are symmetrical to each other, the molding of the magnet 4 and the assembly of the member 8 can be facilitated.

  Further, the magnet 4 may be provided with a magnetic shield body using a magnetic shield material instead of the hole 42. Specifically, for example, as shown in FIGS. 12 and 13, a substantially disk-shaped magnetic shield 43 may be arranged on the surface of the magnet 4 facing the sensor 5. Thereby, as in the example shown in FIG. 5, the magnitude of the magnetic flux density in the vicinity of the center of the magnet 4 can be reduced. As a result, the same effect as when the hole 42 is provided in the magnet 4 can be obtained.

  Further, the application of the rotary actuator 100 is not limited to the VG actuator, and is not limited to the vehicle-mounted actuator. However, in an in-vehicle actuator, particularly in a VG actuator, the environmental temperature fluctuates greatly, and vibration easily causes rattling of the member 8. Therefore, the magnetic flux density B at the position of the sensor 5 tends to fluctuate, which is suitable for using the rotary actuator 100 of the first embodiment.

  As described above, the rotary actuator 100 according to the first embodiment is provided at one end of the shaft 2 and is arranged so as to face the magnet 4 via the air gap 7 and the magnet 4 rotatable integrally with the shaft 2. And a sensor 5 for detecting the rotation angle of the shaft 2 by detecting the magnetic field generated by the magnet 4, the magnet 4 corresponding to the first half 4N corresponding to the N pole and the S pole. The second half 4S and the hole 42 or the magnetic shield 43 are provided between the first half 4N and the second half 4S. The magnetic field across the shield body 43 is detected. As a result, the value of the magnetic flux density B at the position of the sensor 5 can be kept within the detectable range ΔB regardless of the width W of the air gap 7 and the ambient temperature. As a result, it becomes easy to keep the value of the magnetic flux density B at the position of the sensor 5 within the detectable range ΔB.

  The hole 42 or the magnetic shield 43 is provided between the central portion 41N of the first half portion 4N and the central portion 41S of the second half portion 4S, and the sensor 5 is provided in the first half portion 4N. The magnetic field generated between the central portion 41N and the central portion 41S of the second half portion 4S is detected. Accordingly, the rotary actuator 100 can be realized by using the magnet 4 illustrated in FIGS. 2 and 3, 8 and 9, 10 and 11, or 12 and 13.

  Further, the magnet 4 is provided with a hole 42, and the hole 42 is formed by a through hole. Accordingly, the rotary actuator 100 can be realized by using the magnet 4 illustrated in FIGS. 2 and 3.

  Further, the magnet 4 is provided with a hole 42, and the hole 42 is composed of a recess formed in a surface of the magnet 4 facing the sensor 5. As a result, the rotary actuator 100 can be realized by using the magnet 4 illustrated in FIGS. 8 and 9.

  Further, the magnet 4 is provided with a hole 42, and the hole 42 has a first recess 42 a formed in a surface of the magnet 4 facing the sensor 5 and a second recess formed in a back surface of the magnet 4 facing the sensor 5. And 42b. As a result, the rotary actuator 100 can be realized by using the magnet 4 illustrated in FIGS. 10 and 11.

  Further, the magnet 4 is provided with a magnetic shield body 43, and the magnetic shield body 43 is arranged on the surface of the magnet 4 facing the sensor 5. Accordingly, the rotary actuator 100 can be realized by using the magnet 4 illustrated in FIGS. 12 and 13.

  It should be noted that the invention of the present application is capable of modifying any of the constituent elements of the embodiment or omitting any of the constituent elements of the embodiment within the scope of the invention.

  The rotary actuator of the present invention can be used, for example, in a vehicle-mounted VG actuator.

  1 gear, 2 shaft, 3 output lever, 4 magnet, 4N 1st half part, 4S 2nd half part, 5 sensor, 6 electronic circuit board, 7 air gap, 8 member, 41N central part, 41S central part, 42 hole Part, 42a 1st recessed part, 42b 2nd recessed part, 43 magnetic shield body, 51 detection surface, 100 rotary actuator.

Claims (4)

A magnet that is provided at one end of the shaft and is rotatable integrally with the shaft,
A sensor that is arranged to face the magnet via an air gap, and that detects a rotation angle of the shaft by detecting a magnetic field generated by the magnet,
The magnet is composed of a first half corresponding to the N pole and a second half corresponding to the S pole, and a hole or a magnetic shield is provided between the first half and the second half. The body is provided,
The sensor is for detecting the magnetic field straddling the hole or the magnetic shield body,
The hole is provided in the magnet,
The hole is rotating actuator you, characterized in that it is constituted by recesses formed in opposite surface relative to the sensor in the magnet. A magnet that is provided at one end of the shaft and is rotatable integrally with the shaft,
A sensor that is arranged to face the magnet via an air gap, and that detects a rotation angle of the shaft by detecting a magnetic field generated by the magnet,
The magnet is composed of a first half corresponding to the N pole and a second half corresponding to the S pole, and a hole or a magnetic shield is provided between the first half and the second half. The body is provided,
The sensor is for detecting the magnetic field straddling the hole or the magnetic shield body,
The hole is provided in the magnet,
The hole portion includes a first recess formed on the opposing face to said sensor in said magnet, second recess and that is configured wherein the to that rotating equation by which is formed on the rear surface portion with respect to the opposing surface Actuator. A magnet that is provided at one end of the shaft and is rotatable integrally with the shaft,
A sensor that is arranged to face the magnet via an air gap, and that detects a rotation angle of the shaft by detecting a magnetic field generated by the magnet,
The magnet is composed of a first half corresponding to the N pole and a second half corresponding to the S pole, and a hole or a magnetic shield is provided between the first half and the second half. The body is provided,
The sensor is for detecting the magnetic field straddling the hole or the magnetic shield body,
The magnetic shield body is provided on the magnet,
The magnetic shield body, characterized in that arranged on the opposite face with respect to the sensor in the magnetic rotating actuator. A VG actuator using the rotary actuator according to any one of claims 1 to 3 .

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