JPWO2018198235A1 - Rotary actuator and VG actuator - Google Patents

Abstract

The rotary actuator (100) is provided at one end of the shaft (2). And a sensor (5) that detects the rotation angle of the shaft (2) by detecting the magnetic field generated by the magnet (4), and the magnet (4) corresponds to the N pole. It is composed of one half (4N) and a second half (4S) corresponding to the S pole, and a hole (42) between the first half (4N) and the second half (4S). Alternatively, a magnetic shield body (43) is provided, and the sensor (5) detects a magnetic field straddling the hole (42) or the magnetic shield body (43).

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. In addition, an actuator for controlling the opening degree of the nozzle vane in the VG turbocharger, that is, a so-called “VG actuator” has been developed. As the VG actuator, an electrically controlled rotary actuator is used.

  The VG actuator is provided with a mechanism for detecting 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 together with the shaft. The sensor is disposed opposite to 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 values of 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. For this reason, in the mechanism for detecting the rotation angle of the shaft, it is required that the value of the magnetic flux density at the sensor position be within the detectable range. However, since the magnetic flux density at the position of the sensor varies due to the following factors, it is 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 the design dimension of each part is given a margin from the viewpoint of absorbing the dimensional variation of each part. For this reason, the VG actuator has a backlash between components, and the width of the air gap varies due to this backlash. The magnetic flux density at the sensor position increases in a quadratic function as the width of the air gap decreases. Here, in order to reduce the backlash and reduce the variation amount of the width of the air gap, it is conceivable to increase the dimensional accuracy of each component. However, in this case, there is a problem that the unit price of each part increases and the unit price of the VG actuator also increases.

  Second, the magnetic flux density of the magnetic field generated by the magnet varies depending on the environmental temperature. For this reason, the magnetic flux density at the position of the sensor also varies according to the environmental temperature. Therefore, even if the variation amount of the width of the air gap is reduced by increasing the dimensional accuracy of each part, 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-described problems, and provides a rotary actuator and a VG actuator that can easily keep the value of the magnetic flux density at the sensor position within the detectable range. Objective.

  The rotary actuator according to the present invention is provided at one end of the shaft, and is disposed so as to face the magnet through an air gap and a magnet that can rotate integrally with the shaft, and detects a magnetic field generated by the magnet. And a sensor for detecting the rotation angle of the shaft, and the magnet is composed of a first half corresponding to the N pole and a second half corresponding to the S pole, and the first half 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.

  According to the present invention, since it is configured as described above, it is possible to obtain a rotary actuator and a VG actuator that can easily fit the value of the magnetic flux density at the sensor position 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. It is a top view of the magnet which concerns on Embodiment 1 of this invention. It is sectional drawing which follows the A-A 'line | wire shown in FIG. It is explanatory drawing which shows distribution of the magnetic flux density by the magnetic field produced between the center part of the 1st half part, and the center part of the 2nd half part when the magnet which does not have a hole part is used. It is explanatory drawing which shows distribution of the magnetic flux density by the magnetic field produced between the center part of the 1st half part, and the center part of the 2nd half part when the magnet which has a hole part is used. Characteristic indicating magnetic flux density at the position of the sensor due to a magnetic field generated between the central part of the first half and the central part of the second half with respect to the width of the air gap when a magnet having no hole is used FIG. The characteristic figure which shows the magnetic flux density in the position of the sensor by the magnetic field generated between the central part of the 1st half part and the central part of the 2nd half part to the width of an air gap at the time of using the magnet which has a hole. It is. It is a top view of the other magnet which concerns on Embodiment 1 of this invention. It is sectional drawing which follows the A-A 'line shown in FIG. It is a top view of the other magnet which concerns on Embodiment 1 of this invention. It is sectional drawing which follows the A-A 'line | wire shown in FIG. It is a top view of the other magnet which concerns on Embodiment 1 of this invention. It is sectional drawing which follows the A-A 'line | wire shown in FIG.

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

Embodiment 1 FIG.
FIG. 1 is an explanatory diagram showing a main part of the rotary actuator according to the first embodiment of the present invention. FIG. 2 is a plan view of the magnet according to Embodiment 1 of the present invention. 3 is a cross-sectional view taken along 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 an in-vehicle VG actuator.

  In the figure, 1 is a gear. The gear 1 is rotated 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 arrow A2 shown in FIG. 1), and the output lever 3 is rotated when the shaft 2 rotates. The rotation of the output lever 3 changes the opening degree of the nozzle vane provided in the VG turbocharger (not shown).

  A substantially disc-shaped magnet 4 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”) 4N and a substantially semi-disc-shaped portion corresponding to the S pole (hereinafter referred to as “first half”). It is referred to as “second half”.) 4S. A hole 42 is provided between the central portion 41N of the first half 4N and the central portion 41S of the second half 4S. That is, the hole 42 is disposed at the center of the magnet 4 and is disposed on the rotation axis A1. As shown in FIGS. 2 and 3, the hole portion 42 is configured by a substantially cylindrical through hole along the rotation axis A <b> 1.

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

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

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

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

  Next, with reference to FIGS. 4-7, the effect by having provided the hole 42 in the magnet 4 is demonstrated.

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

  In each of FIG.4 and FIG.5, the thickness of a broken line and the shade of a color represent the magnitude | size of magnetic flux density. As shown in FIGS. 4 and 5, by using the magnet 4 having the hole 42, the magnetic flux density in the vicinity of the center of the magnet 4 is larger than when the magnet 4 having no hole 42 is used. The thickness can be reduced.

  FIG. 6 shows a case where the magnet 4 that does not have the hole 42 is used and the width W of the air gap 7 between the central portion 41N of the first half 4N and the central portion 41S of the second half 4S. It is a characteristic view which shows magnetic flux density B in the position of the sensor 5 by the generated magnetic field. FIG. 7 shows a case where the magnet 4 having the hole 42 is used and is formed between the central portion 41N of the first half 4N and the central portion 41S of the second half 4S with respect to the width W of the air gap 7. It is a characteristic view which shows magnetic flux density B in the position of the sensor 5 by the magnetic field, ie, the magnetic field straddling the hole part.

  In each of FIGS. 6 and 7, ΔW indicates a range in which the width W varies due to rattling of the member 8, and ΔB indicates a range of values of the magnetic flux density B that can be detected by the sensor 5, that is, a detectable range. A4 indicates a region of 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 that the environmental temperature is approximately 25 ° C. The characteristic line at a certain time is shown.

  That is, in the range where the characteristic line I is included in the region A4, the sensor 5 can normally detect the rotation angle of the shaft 2 in a temperature environment of approximately −40 ° C. In a range where the characteristic line II is included in the region A4, the sensor 5 can normally detect the rotation angle of the shaft 2 in a temperature environment of about 150 ° C. In a range where the characteristic line III is included in the region 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 that does not have the hole 42 is used, the magnitude of the magnetic flux density near the center of the magnet 4 increases (see FIG. 4). For this reason, 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 region A5 shown in FIG. 6). As a result, the characteristic lines I to III deviate from the region 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., the magnetic flux density B is higher than the upper limit value of the detectable range ΔB when the width W of the air gap 7 is less than approximately 1.9 millimeters (mm). Is also a large value. When the environmental temperature is about 150 ° C., the magnetic flux density B is larger than the upper limit value of the detectable range ΔB when the width W of the air gap 7 is less than about 1.2 mm. When the environmental temperature is approximately 25 ° C., the magnetic flux density B is larger than the upper limit value of the detectable range ΔB when the width W of the air gap 7 is less than approximately 1.7 mm.

  On the other hand, by using the magnet 4 having the hole 42, the magnetic flux density in the vicinity of the center of the magnet 4 can be reduced (see FIG. 5). Thereby, compared with the case where the magnet 4 which does not have the hole part 42 is used, the increase in the magnetic flux density B with respect to the reduction | decrease of the width W can be made loose (refer FIG.6 and FIG.7). As a result, regardless of the width W of the air gap 7 and the environmental temperature, the value of the magnetic flux density B at the position of the sensor 5 can be within the detectable range ΔB (see FIG. 7).

  That is, by using the magnet 4 having the hole 42, it is easy to fit 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 it is possible to prevent an increase in the unit price of the rotary actuator 100. Furthermore, 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.

  Note that the shape of the hole 42 is not limited to the through hole shown in FIGS. 2 and 3. The hole part 42 should just be formed in the opposing surface part with respect to the sensor 5 in the magnet 4 at least.

  Specifically, for example, as shown in FIG. 8 and FIG. 9, the hole 42 may be configured by a substantially hemispherical recess formed in a surface of the magnet 4 facing the sensor 5. Thereby, the magnitude | size of the magnetic flux density in the vicinity of the center part of the magnet 4 can be made small like the example shown in FIG. As a result, the same effect as that obtained when the magnet 4 is provided with a through hole can be obtained.

  Alternatively, for example, as shown in FIGS. 10 and 11, the hole 42 has a substantially hemispherical concave portion (hereinafter referred to as “first concave portion”) 42 a formed on the surface of the magnet 4 facing the sensor 5, and the opposing portion. It may be constituted by a substantially hemispherical concave portion (hereinafter referred to as “second concave portion”) 42 b formed on the back surface portion with respect to the surface portion. Thereby, the magnitude | size of the magnetic flux density in the vicinity of the center part of the magnet 4 can be made small like the example shown in FIG. As a result, it is possible to obtain the same effect as when a through hole is provided in the magnet 4 or when a concave portion is provided only on the surface facing the sensor 5. Moreover, since the shape of the half part by the side of the opposing surface part of the magnet 4 and the shape of the half part by the side of a back surface part are mutually symmetrical, the shaping | molding of the magnet 4 and the assembly of the member 8 can be made easy.

  The magnet 4 may be a magnet 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 body 43 may be disposed on the surface of the magnet 4 facing the sensor 5. Thereby, the magnitude | size of the magnetic flux density in the vicinity of the center part of the magnet 4 can be made small like the example shown in FIG. As a result, the same effect as when the hole 42 is provided in the magnet 4 can be obtained.

  The use 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 a VG actuator, the environmental temperature fluctuates greatly, and the member 8 is likely to be loose due to vibration. For this reason, the magnetic flux density B at the position of the sensor 5 is likely to fluctuate, which is suitable for using the rotary actuator 100 of the first embodiment.

  As described above, the rotary actuator 100 according to Embodiment 1 is provided at one end of the shaft 2, and is disposed so as to face the magnet 4 via the magnet 4 that can rotate integrally with the shaft 2 and the air gap 7. And a sensor 5 that detects the rotation angle of the shaft 2 by detecting the magnetic field generated by the magnet 4, and the magnet 4 corresponds to the first half 4N corresponding to the N pole and the S pole. The hole portion 42 or the magnetic shield body 43 is provided between the first half portion 4N and the second half portion 4S, and the sensor 5 includes the hole portion 42 or the magnetic portion. A magnetic field straddling the shield body 43 is detected. Thereby, the value of the magnetic flux density B at the position of the sensor 5 can be within the detectable range ΔB regardless of the width W of the air gap 7 and the environmental 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 body 43 is provided between the central portion 41N of the first half 4N and the central portion 41S of the second half 4S, and the sensor 5 is connected to the first half 4N. A magnetic field generated between the central portion 41N and the central portion 41S of the second half 4S is detected. Accordingly, the rotary actuator 100 can be realized using the magnet 4 illustrated in FIGS. 2 and 3, 8 and 9, 10 and 11, or 12 and 13.

  Moreover, the hole part 42 is provided in the magnet 4, and the hole part 42 is comprised by the through-hole. Thereby, the rotary actuator 100 is realizable using the magnet 4 illustrated in FIG.2 and FIG.3.

  Moreover, the hole part 42 is provided in the magnet 4, The hole part 42 is comprised by the recessed part formed in the opposing surface part with respect to the sensor 5 in the magnet 4. FIG. Accordingly, the rotary actuator 100 can be realized using the magnet 4 illustrated in FIGS. 8 and 9.

  Moreover, the hole part 42 is provided in the magnet 4, The hole part 42 is the 1st recessed part 42a formed in the opposing surface part with respect to the sensor 5 in the magnet 4, and the 2nd recessed part formed in the back surface part with respect to the said opposing surface part. 42b. Accordingly, the rotary actuator 100 can be realized 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 disposed on a surface of the magnet 4 facing the sensor 5. Accordingly, the rotary actuator 100 can be realized using the magnet 4 illustrated in FIGS. 12 and 13.

  In the present invention, any constituent element of the embodiment can be modified or any constituent element of the embodiment can be omitted within the scope of the invention.

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

  1 gear, 2 shaft, 3 output lever, 4 magnet, 4N first half, 4S second half, 5 sensor, 6 electronic circuit board, 7 air gap, 8 member, 41N center, 41S center, 42 holes Part, 42a 1st recessed part, 42b 2nd recessed part, 43 Magnetic shield body, 51 Detection surface, 100 Rotary actuator.

The rotary actuator according to the present invention is provided at one end of the shaft, and is disposed so as to face the magnet through an air gap and a magnet that can rotate integrally with the shaft, and detects a magnetic field generated by the magnet. And a sensor for detecting the rotation angle of the shaft, and the magnet is composed of a first half corresponding to the N pole and a second half corresponding to the S pole, and the first half 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 constituted by a recess formed in a surface of the magnet facing the sensor.

Claims (7)

A magnet that is provided at one end of the shaft and is rotatable together with the shaft;
A sensor that is disposed opposite to 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 includes 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 rotary actuator characterized in that the sensor detects the magnetic field straddling the hole or the magnetic shield body. The hole or the magnetic shield body is provided between a central portion of the first half and a central portion of the second half,
The rotary actuator according to claim 1, wherein the sensor detects the magnetic field generated between a central portion of the first half portion and a central portion of the second half portion. The hole is provided in the magnet;
The rotary actuator according to claim 1, wherein the hole portion includes a through hole. The hole is provided in the magnet;
The rotary actuator according to claim 1, wherein the hole portion is configured by a concave portion formed in a surface portion of the magnet facing the sensor. The hole is provided in the magnet;
The said hole part is comprised by the 1st recessed part formed in the opposing surface part with respect to the said sensor in the said magnet, and the 2nd recessed part formed in the back surface part with respect to the said opposing surface part. Rotary actuator. The magnet is provided with the magnetic shield body,
The rotary actuator according to claim 1, wherein the magnetic shield body is disposed on a surface portion of the magnet facing the sensor.   A VG actuator using the rotary actuator according to claim 1.

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