JP2019138290A - Permanent magnet, opening detection device, and throttle device - Google Patents

Abstract

To provide a technique for restraining abrasion powder on a surface of a permanent magnet from coming into contact with a magnetic sensor.SOLUTION: A permanent magnet is used together with a magnetic sensor, and may comprise a groove arranged on a boundary surface between a south pole portion and a north pole portion over the whole length of a surface opposed to the magnetic sensor.SELECTED DRAWING: Figure 1

Description

  The present specification discloses a throttle device including an opening degree detection device.

  Patent Document 1 discloses a throttle device. The throttle device includes a throttle body having an intake passage, a throttle valve, a throttle shaft, a coil spring, a rotation angle sensor, and a permanent magnet. The throttle valve opens and closes the intake passage. The throttle shaft is connected to the throttle valve. The coil spring urges the throttle valve in the rotation direction of the throttle valve. The rotation angle sensor faces one end of the throttle shaft. The permanent magnet is disposed with a gap from the rotation angle sensor. When the throttle valve rotates, the permanent magnet rotates around the rotation angle sensor while maintaining a certain clearance from the rotation angle sensor. The rotation angle sensor detects the opening degree of the intake passage based on a change in magnetic flux due to rotation of the permanent magnet.

JP 2008-240610 A

  There is a demand for downsizing the throttle device. In order to reduce the size of the throttle device, it is conceivable to reduce the size of the entire throttle device by reducing the coil spring in the axial direction. In this case, the distance between the coil spring strands is reduced. In this configuration, as the throttle valve rotates, the adjacent strands of the coil springs approach each other and come into contact with each other, so that the strands may wear and generate wear powder from the coil spring. In this case, the wear powder is attracted to the permanent magnet and is deposited on the surface of the permanent magnet on the side facing the rotation angle sensor. When the wear powder on the surface of the permanent magnet contacts the rotation angle sensor, the rotation angle sensor may not be able to accurately detect the opening degree of the intake flow path.

  In this specification, the technique which suppresses that the abrasion powder on the surface of a permanent magnet contacts a magnetic sensor is provided.

  The permanent magnet disclosed by this specification is a permanent magnet used with a magnetic sensor, Comprising: It arrange | positions on the boundary surface of a south pole part and a north pole part over the full length of the surface facing the said magnetic sensor. A groove may be provided.

  According to said structure, abrasion powder is arrange | positioned on the said interface of the strongest magnetic force which each magnetic flux of the S pole part and N pole part of a permanent magnet cross | intersects, ie, the S pole part and N pole part. Is deposited in the groove. For this reason, it can suppress that the abrasion powder on the surface of the permanent magnet facing the magnetic sensor accumulates to the magnetic sensor. As a result, it can suppress that abrasion powder contacts a magnetic sensor.

  The depth of the groove of the permanent magnet is maximum on the boundary surface in a section cut perpendicularly to the boundary surface of the S pole portion and the N pole portion, and is separated from the boundary surface. It may be shallower according to. According to this configuration, the depth of the groove can be made deepest on the boundary surface between the S pole portion and the N pole portion having the strongest magnetic force, that is, at the position where the wear powder is most deposited.

  The opening detection device is opposed to the permanent magnet whose magnetic flux changes in accordance with the opening of the valve body, with the surface on which the groove of the permanent magnet is disposed, having a gap, and You may provide the said magnetic sensor which detects a change. According to this structure, it can suppress that the abrasion powder on the surface of a permanent magnet accumulates to a magnetic sensor. As a result, it can suppress that abrasion powder contacts a magnetic sensor. Thereby, it can suppress that an opening degree detection apparatus misdetects the magnetic flux of wear powder.

  The throttle device includes a storage chamber that stores the opening degree detection device, a main body including a flow path, the valve body that is disposed in the flow path and opens and closes the flow path, and the storage chamber. And a coil spring that biases the valve body. According to this structure, it can suppress that the abrasion powder on the surface of a permanent magnet accumulates to a magnetic sensor. As a result, it can suppress that abrasion powder contacts a magnetic sensor. Thereby, it can suppress that an error arises in the opening degree of the channel of a throttle device.

  The throttle device is accommodated in the accommodation chamber, and includes a wall portion surrounding a gap between the magnetic sensor and the permanent magnet, and the wall portion may be disposed between the coil spring and the permanent magnet. Good. According to this configuration, wear powder that enters the gap between the permanent magnet and the magnetic sensor is reduced by the wall portion disposed between the permanent magnet and the coil spring. For this reason, the abrasion powder on the surface of a permanent magnet can be reduced. As a result, it can suppress that abrasion powder contacts a magnetic sensor. Thereby, it can suppress that an error arises in the opening degree of the channel of a throttle device.

  In the throttle device, the main body includes a valve main body and a cover that covers a side surface of the valve main body, the cover defining the storage chamber by the valve main body and the cover, and the wall portion. Is disposed with a gap from the surface of the cover on the valve body side, and the cover is disposed on the radially inner side of the coil spring with respect to the coil spring, and the surface on the valve body side An annular portion extending from the wall portion toward the valve body, the annular portion extending beyond the gap between the wall portion and the surface of the cover on the valve body side, and the valve body of the annular portion The side end may be disposed so as to overlap the wall portion in the radial direction of the coil spring. According to this configuration, the permanent magnet and the magnetic sensor are extended by the annular portion that extends beyond the gap between the wall portion and the surface of the valve body side of the cover, and that overlaps the wall portion in the radial direction of the coil spring. The wear powder entering the gap is further reduced. For this reason, the abrasion powder on the surface of the permanent magnet can be further reduced. As a result, it can suppress that abrasion powder contacts a magnetic sensor. Thereby, it can suppress that an error arises in the opening degree of the channel of a throttle device.

It is sectional drawing of the throttle apparatus of an Example. It is sectional drawing to which the part accommodated in the storage chamber of the throttle device of an Example was expanded. It is a perspective view of the permanent magnet of an Example. It is a perspective view of a throttle gear and a permanent magnet of an example. It is sectional drawing which took out the cover of the throttle apparatus of an Example, throttle gear, and the opening degree detection apparatus.

(Example)
(Configuration of throttle device)
A throttle device 10 of the present embodiment will be described with reference to FIGS. The throttle device 10 is mounted on a vehicle including an internal combustion engine such as an automobile. The throttle device 10 is disposed on an intake passage that communicates the intake port of the vehicle and the internal combustion engine. The throttle device 10 adjusts the amount of air supplied to the internal combustion engine of the vehicle by opening and closing the intake passage in accordance with a command from an unillustrated vehicle engine control unit (ECU).

  As shown in FIG. 1, the throttle device 10 includes a main body 12, a valve body 20, a valve shaft 22, a coil spring 36, a throttle gear 40, an opening detection device 43, an intermediate gear 30, and an intermediate shaft. 28, a motor gear 26, and a motor 24. FIG. 1 is a cross-sectional view of the throttle device 10 when the throttle device 10 is cut perpendicularly to a central axis of a flow path 18 to be described later. In FIG. 1, for ease of viewing, parallel oblique lines indicating a cross section are omitted from the valve shaft 22 described later. Moreover, in FIG. 1, the valve body 20 mentioned later is not cut | disconnected.

(Structure of the valve body)
The main body 12 includes a valve main body 14, a cover 16, and a storage chamber 34. The valve body 14 is made of an aluminum alloy. The valve body 14 includes a flow path 18. The flow path 18 passes through the valve body 14. The flow path 18 is disposed on the intake flow path of the vehicle. A cover 16 is disposed on the valve body 14. The cover 16 is made of resin. The cover 16 covers a side surface parallel to the flow path 18 of the valve body 14. A storage chamber 34 is defined by the valve body 14 and the cover 16. The cover 16 includes an annular portion 48. The annular portion 48 is located on the surface of the cover 16 on the valve body 14 side. The annular portion 48 has a cylindrical shape. The annular portion 48 extends from the surface of the cover 16 on the valve body 14 side toward the valve body 14. The accommodation chamber 34 accommodates one end of the valve shaft 22, the coil spring 36, the throttle gear 40, the opening degree detection device 43, the intermediate gear 30, the intermediate shaft 28, the motor gear 26, and the motor 24.

  A valve body 20 is disposed in the flow path 18. The valve body 20 has a circular flat plate shape. The valve body 20 is supported by the valve shaft 22. The valve shaft 22 has a cylindrical shape. The central axis of the valve shaft 22 coincides with the central axis of the annular portion 48. The valve shaft 22 passes through the valve body 14 and protrudes into the accommodation chamber 34. The valve shaft 22 is rotatably supported by the valve body 14. For this reason, the valve body 20 rotates with respect to the valve body 14 around the valve shaft 22. Thereby, the valve body 20 can rotate between a valve closing state in which the flow path 18 is closed and a valve opening state in which the flow path 18 is opened, and opens and closes the flow path 18.

  As shown in FIG. 2, a throttle gear 40 is connected to the end of the valve shaft 22 on the side of the accommodation chamber 34. FIG. 2 is an enlarged view of a portion of the valve shaft 22 accommodated in the accommodation chamber 34 in the cross-sectional view of the throttle device 10 of FIG. The throttle gear 40 is made of resin. The throttle gear 40 is disposed with a gap from the cover 16. The throttle gear 40 is rotatably supported by the valve body 14 via the valve shaft 22. The throttle gear 40 rotates around the central axis of the valve shaft 22. That is, when the throttle gear 40 rotates, the valve body 20 rotates around the valve shaft 22. The throttle gear 40 includes a wall portion 42. The wall part 42 has a cylindrical shape. The central axis of the wall portion 42 coincides with the central axis of the valve shaft 22. The wall portion 42 is disposed on the surface of the throttle gear 40 that faces the cover 16. The diameter of the inner peripheral surface of the wall portion 42 is larger than the diameter of the outer peripheral surface of the annular portion 48. The wall portion 42 is disposed with a clearance from the outer peripheral surface of the annular portion 48. The wall 42 extends from the surface of the throttle gear 40 facing the cover 16 toward the cover 16. The wall portion 42 is disposed with a slight gap from the surface of the cover 16 on the valve body 14 side. An annular portion 48 is disposed on the radially inner side of the wall portion 42 in the gap between the wall portion 42 and the cover 16.

  As shown in FIG. 1, the intermediate gear 30 is engaged with the throttle gear 40. The intermediate gear 30 is made of resin. The intermediate gear 30 is connected to the intermediate shaft 28. The intermediate gear 30 is rotatably supported by the valve body 14 via the intermediate shaft 28. A motor gear 26 is engaged with the intermediate gear 30. The motor gear 26 is made of resin. The motor gear 26 is connected to the drive shaft of the motor 24. The motor 24 is a stepping motor. The motor 24 is driven according to a command from the ECU. When the motor 24 is driven, the drive shaft of the motor 24 rotates stepwise. As a result, the throttle gear 40 rotates via the motor gear 26 and the intermediate gear 30. Thereby, the valve body 20 rotates around the valve shaft 22.

(Configuration of coil spring)
A coil spring 36 is attached to the throttle gear 40. A valve shaft 22 is disposed inside the coil spring 36. The central axis of the coil spring 36 coincides with the central axis of the valve shaft 22. An annular portion 48 and a wall portion 42 are arranged on the radially inner side of the coil spring 36 with respect to the coil spring 36. The coil spring 36 is provided via the throttle gear 40 so as to maintain the valve body 20 at a position where the valve body 20 is opened from the fully closed state. For this reason, in the initial state where the valve body 20 is not rotated by the motor 24, the flow path 18 is slightly opened. In the initial state, the coil springs 36 adjacent to each other are in contact with each other. When the throttle gear 40 rotates, the coil spring 36 is elastically deformed in the direction in which the coil diameter decreases. Thereby, the coil spring 36 biases the valve body 20 toward the initial state.

(Permanent magnet configuration)
The opening detection device 43 includes a permanent magnet 44 and a magnetic sensor 50. As shown in FIG. 3, the permanent magnet 44 has a cylindrical shape, and a flat surface is provided on a part of the outer peripheral surface. The permanent magnet 44 has a pair of an S pole portion 44a and an N pole portion 44b. The pair of S pole portion 44a and N pole portion 44b is separated by a boundary surface BD indicated by a one-dot chain line. The permanent magnet 44 includes a groove 46. The groove 46 is disposed on the surface 44 c of the permanent magnet 44. The groove 46 is disposed on the boundary surface BD. On the surface 44c of the permanent magnet 44, the groove 46 is continuous over the entire length of the boundary surface BD. The groove 46 has a V shape in the cross section of the permanent magnet 44 cut perpendicular to the boundary surface BD. The depth of the groove 46 is maximum on the boundary surface BD, and gradually becomes shallower as the distance from the boundary surface BD increases. In the boundary surface BD, the depth of the groove 46 is constant over the entire length of the boundary surface BD.

  As shown in FIGS. 1, 2, and 4, the permanent magnet 44 is disposed on the inner peripheral side of the wall portion 42. The permanent magnet 44 is attached to the throttle gear 40. The central axis of the permanent magnet 44 coincides with the central axis of the valve shaft 22. Thereby, the direction of the magnetic flux of the permanent magnet 44 changes with the rotation of the throttle gear 40. The side surface of the permanent magnet 44 is surrounded by the wall portion 42. The wall portion 42 is disposed between the permanent magnet 44 and the coil spring 36. The wall 42 extends beyond the surface 44c of the permanent magnet 44 to the cover 16 side. A surface 44 c of the permanent magnet 44 faces the annular portion 48.

(Configuration of magnetic sensor)
As shown in FIG. 5, a magnetic sensor 50 is disposed on the inner peripheral side of the annular portion 48. FIG. 5 is a diagram in which the cover 16, the throttle gear 40, and the opening degree detection device 43 are taken out from the cross-sectional view of the throttle device 10 of FIG. The magnetic sensor 50 is surrounded by the annular portion 48. The annular portion 48 extends beyond the surface of the magnetic sensor 50 to the permanent magnet 44 side. The end of the annular portion 48 on the valve body 14 side, that is, the end on the permanent magnet 44 side is disposed with a slight gap from the permanent magnet 44. The annular portion 48 extends beyond the gap between the wall portion 42 and the cover 16. The end of the annular portion 48 on the permanent magnet 44 side is disposed so as to overlap the wall portion 42 in the radial direction of the coil spring 36. The magnetic sensor 50 faces the surface 44c of the permanent magnet 44 with a gap. A gap between the magnetic sensor 50 and the permanent magnet 44 is surrounded by the wall portion 42.

  The magnetic sensor 50 detects the direction of the magnetic flux of the permanent magnet 44. The magnetic sensor 50 transmits the detected direction of the magnetic flux of the permanent magnet 44 to the ECU. The ECU detects the opening degree of the flow path 18 based on the change in the direction of the magnetic flux of the permanent magnet 44 transmitted from the magnetic sensor 50.

(Throttle device operation)
Next, the operation of the throttle device 10 will be described. When the motor 24 obtains a drive start command from the ECU, the motor 24 is driven according to the command. As a result, the motor gear 26 is rotated and the throttle gear 40 is rotated via the intermediate gear 30. Thereby, the valve body 20 is rotated around the valve shaft 22, and the opening degree of the flow path 18 is controlled. The magnetic sensor 50 detects the direction of the magnetic flux of the permanent magnet 44 rotating with the rotation of the throttle gear 40 and transmits it to the ECU. Thereby, the ECU detects the opening degree of the flow path 18.

(effect)
As the throttle gear 40 rotates, the coil spring 36 is elastically deformed in the direction in which the coil diameter decreases. As a result, the coil springs 36 that are in contact with each other rub against each other and wear between the strands of the coil springs 36. As a result, wear powder is generated from the coil spring 36. The wear powder is attracted to the permanent magnet 44. In particular, the wear powder is attracted and deposited on the boundary surface BD between the south pole portion 44a and the north pole portion 44b of the permanent magnet 44, which is the portion having the strongest magnetic force. In the present embodiment, the groove 46 is disposed on the surface 44c of the permanent magnet 44, and is disposed on the boundary surface BD. For this reason, the wear powder accumulates in the groove 46. As a result, it is possible to suppress the abrasion powder on the surface 44 c of the permanent magnet 44 from accumulating up to the magnetic sensor 50. Thereby, it can suppress that abrasion powder contacts the magnetic sensor 50. FIG. Furthermore, the gap between the permanent magnet 44 and the magnetic sensor 50 can be narrowed, and the throttle device 10 can be downsized.

  Further, the depth of the groove 46 is maximum on the boundary surface BD, and gradually becomes shallower as the distance from the boundary surface BD increases. In this configuration, the groove 46 is deepest on the boundary surface BD where the wear powder is most deposited. As a result, for example, the groove 46 can be made smaller than a groove having a constant depth in the direction perpendicular to the boundary surface BD.

  The opening degree detection device 43 includes a permanent magnet 44 and a magnetic sensor 50. The permanent magnet 44 includes a groove 46 disposed on the boundary surface BD. For this reason, it can suppress that the abrasion powder on the surface 44c of the permanent magnet 44 accumulates to the magnetic sensor 50. As a result, it can suppress that abrasion powder contacts the magnetic sensor 50. FIG. Thereby, the opening degree detection apparatus 43 can suppress misdetecting the magnetic flux of wear powder.

  Further, the throttle device 10 includes a main body 12 including a flow path 18 and an opening degree detection device 43. For this reason, it can suppress that the opening degree detection apparatus 43 misdetects the magnetic flux of wear powder. As a result, the occurrence of an error in the opening degree of the flow path 18 of the throttle device 10 can be suppressed.

  Further, the wall portion 42 is accommodated in the accommodation chamber 34. The wall portion 42 is disposed between the permanent magnet 44 and the coil spring 36. The wall 42 extends beyond the surface 44 c of the permanent magnet 44 to the cover 16 side and surrounds the gap between the permanent magnet 44 and the magnetic sensor 50. For this reason, the wall portion 42 can suppress the wear powder from entering the gap between the permanent magnet 44 and the magnetic sensor 50. As a result, the wear powder on the surface 44c of the permanent magnet 44 can be reduced. Thereby, it can suppress that abrasion powder contacts the magnetic sensor 50, and can suppress that an error arises in the opening degree of the flow path 18 of the throttle device 10.

  The annular portion 48 disposed on the inner side in the radial direction of the coil spring 36 is located on the surface of the cover 16 on the valve body 14 side. The annular portion 48 extends beyond the surface of the magnetic sensor 50 to the permanent magnet 44 side, beyond the gap between the wall portion 42 extending toward the cover 16 from the surface facing the cover 16 of the throttle gear 40 and the cover 16. It is growing. The end of the annular portion 48 on the permanent magnet 44 side is disposed so as to overlap the wall portion 42 in the radial direction of the coil spring 36. The annular portion 48 is disposed on the radially inner side of the wall portion 42 in the gap between the wall portion 42 and the cover 16. For this reason, the annular portion 48 can suppress the wear powder that has passed through the gap between the wall portion 42 and the cover 16 from entering the gap between the permanent magnet 44 and the magnetic sensor 50. As a result, the wear powder on the surface 44c of the permanent magnet 44 can be reduced. Thereby, it can suppress that abrasion powder contacts the magnetic sensor 50, and can suppress that an error arises in the opening degree of the flow path 18 of the throttle device 10.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

(Modification)
(1) In the above embodiment, the shape of the groove 46 is not limited to the V shape described in the above embodiment. For example, the groove 46 may have a semicircular shape in the cross section of the permanent magnet 44 cut perpendicularly to the boundary surface BD, and may gradually become shallower as the distance from the boundary surface BD increases.

(2) In the above embodiment, in the boundary surface BD, the depth of the groove 46 is constant over the entire length of the boundary surface BD. However, the depth of the groove 46 may not be constant over the entire length of the boundary surface BD. For example, on the boundary surface BD, the depth of the groove 46 may gradually become shallower as the distance from the center of the permanent magnet 44 increases.

(3) In the above embodiment, the wall portion 42 is disposed with a gap from the outer peripheral surface of the annular portion 48. However, the wall portion 42 may be disposed with a gap from the outer peripheral surface of the annular portion 48. For example, the wall portion 42 may be disposed with a gap from the inner peripheral surface of the annular portion 48.

(4) In the above embodiment, the cover 16 includes one annular portion 48. However, the cover 16 may include two annular portions. For example, the cover 16 may include an annular portion 48 and an annular portion that is disposed with a clearance from the outer peripheral surface of the wall portion 42.

(5) The shape of the permanent magnet 44 is not limited to the cylindrical shape described in the above embodiment. For example, the permanent magnet 44 may have a prismatic shape.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings can achieve a plurality of purposes at the same time, and has technical utility by achieving one of the purposes.

10: Throttle device 12: Main body 14: Valve main body 16: Cover 18: Flow path 20: Valve body 22: Valve shaft 24: Motor 26: Motor gear 28: Intermediate shaft 30: Intermediate gear 34: Storage chamber 36: Coil spring 40: Throttle gear 42: Wall 43: Opening detection device 44: Permanent magnet 44a: S pole portion 44b: N pole portion 44c: Surface 46: Groove 48: Annular portion 50: Magnetic sensor BD: Boundary surface

Claims (6)

A permanent magnet used with a magnetic sensor,
A permanent magnet comprising a groove disposed on the boundary surface between the south pole portion and the north pole portion over the entire length of the surface facing the magnetic sensor. The permanent magnet according to claim 1,
The depth of the groove is maximum on the boundary surface in a cross section cut perpendicularly to the boundary surface between the S pole portion and the N pole portion, and becomes shallower as the distance from the boundary surface becomes permanent. magnet. The permanent magnet according to claim 1 or 2, wherein the magnetic flux changes according to the opening of the valve body,
An opening detection device comprising: the magnetic sensor that detects a change in the magnetic flux that is opposed to the surface on which the groove of the permanent magnet is disposed with a gap. The opening degree detection device according to claim 3,
A storage chamber for storing the opening detection device; a main body including a flow path;
The valve element disposed in the flow path and opening and closing the flow path;
A throttle device comprising: a coil spring housed in the housing chamber and biasing the valve body. The throttle device according to claim 4, further comprising:
It is accommodated in the accommodation chamber, and includes a wall portion surrounding a gap between the magnetic sensor and the permanent magnet,
The said wall part is a throttle device arrange | positioned between the said coil spring and the said permanent magnet. The throttle device according to claim 5,
The body is
A valve body;
A cover that covers a side surface of the valve body, the valve body and the cover defining the storage chamber by the cover; and
The wall portion is disposed with a gap with the surface of the cover on the valve body side,
The cover is disposed radially inward of the coil spring with respect to the coil spring, and includes an annular portion extending from the valve body side surface toward the valve body.
The annular portion extends beyond the gap between the wall portion and the surface of the cover on the valve body side;
A throttle device, wherein an end of the annular portion on the valve main body side is disposed so as to overlap the wall portion in the radial direction of the coil spring.

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