JP2004301685A - Rotational angle detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotational angle detection device capable of improving a detection precision by reducing the tolerance of a gap between a magnet and a magnetic detector element by reducing the number of parts for determining the axial gap. <P>SOLUTION: The rotational angle detection device comprises a substrate support means 67 for supporting the substrate 63 capable of displacement in an axial direction but unable to move in a rotational direction and radial direction, an energizing means 68 for energizing the substrate 63 toward the magnet 61, and a stopper 69 for determination of the axial gap put between the substrate 63 and a magnet 61. The axial gap A is determined by an axial tolerance of the stopper 69 and a fix tolerance of the magnetic detector element 62 on the substrate 63. Therefore, the number of parts for determination of the tolerance of the axial gap A can be made small, and the detection precision can be improved. Heretofore the magnet is supported by the rotational axis via the rotor core, the magnetic detector element is supported by a housing via the substrate, and the bearing is interleaved between the housing and the rotor core, so the tolerance of the gap between the magnet and magnetic detector element is affected by a number of tolerances of parts supporting the magnet and the magnetic detector, so the tolerance of the gap in the axial direction becomes large to solve the problem described above. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotation angle detection device that detects a rotation angle of a rotator using a magnetic change, and more particularly to a technique for improving the accuracy of an axial gap (opposing distance) between a magnet and a magnetic detection element.
[0002]
BACKGROUND OF THE INVENTION
2. Description of the Related Art There is known a rotation angle detection device that arranges a magnetic detection element in an axial direction of a magnet attached to a rotating body and detects a rotation angle of the rotating body by detecting a magnetic change of the magnet with the magnetic detection element.
Since the magnetic force emitted by the magnet has a characteristic of decreasing in inverse proportion to the square of the distance, the accuracy of the axial gap between the magnet and the magnetic detection element is very important for improving the detection accuracy.
[0003]
Therefore, the end of the rotating shaft closer to the magnet is supported by the housing via a rolling bearing. The inner ring of the rolling bearing is press-fitted and fixed to the rotating shaft, and the outer ring of the rolling bearing is press-fitted and fixed to the housing. Then, a substrate for supporting the magnetic detection element is attached to the housing. By adopting such a configuration, a technique has been proposed in which the axial accuracy of the rotating shaft with respect to the housing is increased, and the tolerance of the axial gap between the magnet and the magnetic sensing element is reduced (this is not a known technique: Patent Document 1). reference).
[0004]
[Patent Document 1]
Japanese Patent Application No. 2002-178897
[0005]
[Problems to be solved by the invention]
Even if the magnet is provided so as to support the magnetic detecting element as in the above-mentioned patent document, the magnet is supported by the rotating shaft via a rotating body (such as a rotor core), and the magnetic detecting element is mounted on the housing via a substrate. And a bearing or the like is interposed between the housing and the rotating shaft.
That is, there is an axial gap between the magnet and the magnetic detection element, such as magnet → rotator (rotor core) → rotating shaft → housing → substrate support member → substrate → magnetic detection element between the magnet and the magnetic detection element support structure. Many parts that disturb the accuracy of the device are interposed.
[0006]
The accuracy of the axial gap between the magnet and the magnetic sensing element is determined by adding the dimensional tolerances of many parts supporting the magnet and the magnetic sensing element. It becomes a factor of deterioration of accuracy.
In order to increase the detection accuracy, it is necessary to extremely reduce the dimensional tolerance of a large number of components supporting the magnet and the magnetic detection element, but this is a major factor in increasing costs. Further, if the detection accuracy is to be further improved, it cannot be established with a tolerance. That is, since a large number of components are interposed in the support member between the magnet and the magnetic detection element, the upper limit of the detection accuracy is suppressed.
[0007]
[Object of the invention]
The present invention focuses on the fact that the conventional structure increases the tolerance of the axial gap between the magnet and the magnetic sensing element due to the addition of the dimensional tolerances of a large number of parts supporting the magnet and the magnetic sensing element, thereby deteriorating the detection accuracy. The purpose is to reduce the number of parts that determine the axial gap between the magnet and the magnetic sensing element, thereby reducing the tolerance of the axial gap between the magnet and the magnetic sensing element and increasing the detection accuracy. It is an object of the present invention to provide a rotation angle detecting device capable of detecting a rotation angle.
[0008]
[Means for Solving the Problems]
[Means of claim 1]
A rotation angle detecting device adopting the means of claim 1 is a substrate supporting means for supporting a substrate in such a manner that the substrate can be displaced in an axial direction, and cannot be displaced in a rotational direction and a radial direction, and a device for urging the substrate toward a magnet. And a stopper which is disposed between the substrate and the magnet and forms a predetermined axial gap between the substrate and the magnet.
That is, the axial gap between the magnet and the magnetic sensing element is determined by the axial tolerance of the stopper and the mounting tolerance of the magnetic sensing element on the substrate. Can be significantly reduced as compared with the related art.
[0009]
Thus, by reducing the number of components for determining the tolerance of the axial gap between the magnet and the magnetic sensing element, the tolerance of the axial gap between the magnet and the magnetic sensing element can be reduced, and the detection accuracy of the rotation angle detecting device can be increased. be able to.
That is, the tolerance of the axial gap between the magnet and the magnetic sensing element can be reduced at low cost. Furthermore, since the number of components for determining the tolerance of the axial gap between the magnet and the magnetic detection element can be reduced, the upper limit of the detection accuracy can be increased.
[0010]
[Means of Claim 2]
According to a second aspect of the present invention, there is provided a rotation angle detecting device in which a stopper is provided integrally with one of a housing, a magnet and a substrate on which a substrate is mounted.
With this arrangement, the number of parts can be reduced, parts can be easily managed and assembled, and manufacturing costs can be reduced.
[0011]
[Means of Claim 3]
The rotation angle detecting device adopting the means of claim 3 is provided with a means for reducing the sliding resistance at a portion which slides on the stopper.
The means for reducing the sliding resistance is not limited.
For example, a high-sliding material (for example, ethylene tetrafluoride resin or the like) may be coated on at least one surface of a stopper or a member (a substrate or a magnet) that slides on the stopper.
Further, the stopper may be formed of a high sliding material (for example, ethylene tetrafluoride resin).
Alternatively, a high-sliding material (for example, lubricating oil such as grease or a film such as a tetrafluoroethylene resin) may be interposed between the stopper and a member (a substrate or a magnet) that comes into sliding contact with the stopper.
[0012]
[Means of Claim 4]
According to a fourth aspect of the present invention, there is provided a rotation angle detection device having a window portion penetrating a portion of a substrate on which a magnetic detection element is mounted, and in which the magnetic detection element is mounted.
With this arrangement, the thickness of the substrate and the thickness of the magnetic detection element overlap in the axial direction, so that the rotation angle detection device can be made thinner.
[0013]
[Means of claim 5]
The substrate supporting means of the rotation angle detecting device employing the means of claim 5 is provided in two through holes for positioning formed in the substrate and in a housing that covers the substrate from the opposite side of the magnet, and a minute clearance is provided in the through hole. And two positioning pins extending in the axial direction, which are fitted through each other.
With this arrangement, the positioning of the substrate with respect to the housing can be performed with high accuracy only by inserting the two through holes of the substrate into the two positioning pins provided in the housing.
[0014]
[Means of claim 6]
The rotating body of the rotation angle detecting device employing the means of claim 6 is a rotor in a rotating machine such as an electric motor or a generator, and the magnet is provided to be joined to a rotor core constituting the rotor.
As described above, since the rotation angle detection device is mounted inside the rotating machine, the thickness of the rotation machine equipped with the rotation angle detection device can be reduced.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described using examples and modifications.
〔Example〕
In this embodiment, the present invention is applied to a rotation angle detecting device of an electric motor that generates power for switching in a shift range switching device of an automatic transmission (including a switching device of a parking switching mechanism). The range switching device will be described.
[0016]
(Description of shift range switching device)
The shift range switching device includes a shift range switching device 3 (including a parking switching device 4; see FIG. 4) mounted on the vehicle automatic transmission 2 (see FIG. 3) by the rotary actuator 1 (see FIG. 2). Switch.
The rotary actuator 1 is used as a servo mechanism for driving the shift range switching device 3, and includes a synchronous motor 5 (hereinafter, referred to as an electric motor) and an internally meshing planetary gear reducer 6 (hereinafter, referred to as a reducer). It is constituted by. This embodiment will be described with the right side of FIG. 2 as the front (or front) and the left side as the rear (or rear).
[0017]
(Description of the electric motor 5)
The electric motor 5 will be described with reference to FIGS.
The electric motor 5 according to this embodiment is an SR motor (switched reluctance motor) that does not use a permanent magnet, and includes a rotor 11 rotatably supported and a stator arranged coaxially with the rotation center of the rotor 11. And 12.
[0018]
The rotor 11 includes a rotor shaft 13 and a rotor core 14, and the rotor shaft 13 is rotatably supported by rolling bearings (a front rolling bearing 15 and a rear rolling bearing 16) arranged at a front end and a rear end. .
The front rolling bearing 15 is arranged on the inner periphery of the output shaft 17 of the reduction gear 6, and the output shaft 17 of the reduction gear 6 is rotatable by the metal bearing 19 arranged on the inner periphery of the front housing 18. It is supported by. That is, the front end of the rotor shaft 13 is rotatably supported via the metal bearing 19 → the output shaft 17 → the front rolling bearing 15 provided on the front housing 18.
[0019]
Here, the axial support section of the metal bearing 19 is provided so as to overlap the axial support section of the front rolling bearing 15. With such provision, the inclination of the rotor shaft 13 caused by the reaction force of the speed reducer 6 (specifically, the reaction force of the load applied to the engagement between the external gear 26 and the internal gear 27 described later) is avoided. be able to.
On the other hand, the rear rolling bearing 16 is supported by the rear housing 20.
[0020]
The stator 12 includes a stator core 21 and a coil 22 (specifically, coils 22A to 22L: see FIG. 5).
The stator core 21 is formed by laminating a large number of thin plates, and is fixed to the rear housing 20. The stator core 21 is provided with stator teeth protruding every 30 degrees toward the inner rotor core 14, and coils 22 </ b> A to 22 </ b> L are wound around each of the stator teeth 23. Here, the coils 22A, 22D, 22G, and 22J are in the U phase, the coils 22B, 22E, 22H, and 22K are in the V phase, and the coils 22C, 22F, 22I, and 22L are in the W phase.
[0021]
On the other hand, the rotor core 14 is formed by laminating a number of thin plates, and is press-fitted and fixed to the rotor shaft 13. The rotor core 14 is provided with salient poles 24 protruding every 45 degrees toward the outer stator core 21. When the energization is switched in the order of W phase → V phase → U phase from the state of FIG. 5, the rotor 11 rotates counterclockwise, and conversely, when the energization is switched in the order of V phase → W phase → U phase. The rotor 11 rotates clockwise, and the rotor 11 rotates 45 degrees each time the energization of the U, V, and W phases completes.
[0022]
(Description of reduction gear 6)
The reduction gear 6 will be described with reference to FIGS. 2 and 6 to 8.
The speed reducer 6 includes an external gear 26 (inner gear: sun gear) mounted eccentrically rotatable with respect to the rotor shaft 13 via an eccentric portion 25 provided on the rotor shaft 13, and the external gear 26. Are provided with an internal gear 27 (outer gear: ring gear) internally engaged with the transmission gear 28 for transmitting only the rotation component of the external gear 26 to the output shaft 17.
[0023]
The eccentric portion 25 is a shaft that eccentrically rotates with respect to the rotation center of the rotor shaft 13 and swings and rotates the external gear 26. 26 is rotatably supported.
The external gear 26 is rotatably supported by the eccentric portion 25 of the rotor shaft 13 via the intermediate rolling bearing 31 as described above, and is pressed against the internal gear 27 by the rotation of the eccentric portion 25. It is configured to rotate in the state of being turned.
The internal gear 27 is fixed to the front housing 18 by a fixing projection 32.
[0024]
The transmission means 28 includes a plurality of inner pin holes 34 formed on the same circumference of a flange 33 rotating integrally with the output shaft 17, and a plurality of inner pin holes 34 formed in the external gear 26, each of which fits loosely into the inner pin hole 34. And the inner pin 35.
The plurality of inner pins 35 are provided so as to protrude from the front surface of the external gear 26.
The plurality of inner pin holes 34 are provided on a flange 33 provided at the rear end of the output shaft 17, and the rotation of the external gear 26 is controlled by the engagement of the inner pins 35 and the inner pin holes 34. 17 is transmitted.
With this arrangement, the rotor shaft 13 rotates and the external gear 26 rotates eccentrically, so that the external gear 26 rotates at reduced speed with respect to the rotor shaft 13, and the reduced rotation is transmitted to the output shaft 17. Can be The output shaft 17 is connected to a control rod 45 (described later) of the shift range switching device 3.
Unlike this embodiment, a plurality of inner pin holes 34 may be formed in the external gear 26 and a plurality of inner pins 35 may be provided in the flange 33.
[0025]
(Description of shift range switching device 3)
The shift range switching device 3 will be described with reference to FIG.
The shift range switching device 3 (including the parking switching device 4) is switched by the output shaft 17 of the speed reducer 6 described above.
Switching of each shift range (P, R, N, D) in the automatic transmission 2 is performed by sliding displacement of a manual spool valve 42 provided in the hydraulic control box 41 to an appropriate position.
[0026]
On the other hand, the locking and unlocking of the parking switching device 4 is performed by engaging and disengaging the concave portion 43a of the park gear 43 and the convex portion 44a of the park pole 44. The park gear 43 is connected to an output shaft of the automatic transmission 2 (not shown) via a differential gear (not shown). A locked state is achieved.
[0027]
A detent plate 46 having a substantially fan shape is attached to the control rod 45 driven by the speed reducer 6 by driving a spring pin (not shown) or the like.
The detent plate 46 is provided with a plurality of recesses 46a at the radial end (substantially fan-shaped arc portion), and is switched by the leaf springs 47 fixed to the hydraulic control box 41 fitted into the recesses 46a. The set shift range is maintained.
[0028]
A pin 48 for driving the manual spool valve 42 is attached to the detent plate 46.
The pin 48 is engaged with a groove 49 provided at the end of the manual spool valve 42, and when the detent plate 46 is rotated by the control rod 45, the pin 48 is driven in an arc, and the pin 48 The engaged manual spool valve 42 makes a linear movement inside the hydraulic control box 41.
[0029]
When the control rod 45 is rotated clockwise as viewed from the direction of arrow A in FIG. 4, the pin 48 pushes the manual spool valve 42 into the hydraulic control box 41 via the detent plate 46, and The oil passage is switched in the order of D → N → R → P. That is, the range of the automatic transmission 2 is switched in the order of D → N → R → P.
When the control rod 45 is rotated in the opposite direction, the pin 48 pulls out the manual spool valve 42 from the hydraulic control box 41, and the oil passage in the hydraulic control box 41 is switched in the order of P → R → N → D. That is, the range of the automatic transmission 2 is switched in the order of P → R → N → D.
[0030]
On the other hand, a park rod 51 for driving the park pole 44 is attached to the detent plate 46. A cone 52 is provided at the tip of the park rod 51.
The conical portion 52 is interposed between the projecting portion 53 of the housing of the automatic transmission 2 and the park pole 44. When the control rod 45 is rotated clockwise as viewed from the direction of arrow A in FIG. (Specifically, R → P range), the park rod 51 is displaced in the direction of arrow B in FIG. 4 via the detent plate 46, and the conical portion 52 pushes up the park pole 44. Then, the park pole 44 rotates in the direction of arrow C in FIG. 4 around the shaft 44b, the projection 44a of the park pole 44 engages with the recess 43a of the park gear 43, and the locked state of the parking switching device 4 is achieved. .
[0031]
When the control rod 45 is rotated in the opposite direction (specifically, P → R range), the park rod 51 is pulled back in the direction opposite to the direction of arrow B in FIG. 4, and the force for pushing up the park pole 44 is lost. Since the park pole 44 is constantly urged by a torsion coil spring (not shown) in a direction opposite to the direction of arrow C in FIG. And the parking switching device 4 is unlocked.
[0032]
(Description of rotation angle detection device 60)
The rotation angle detection device 60 will be described with reference to FIGS. 1, 2, 5, 9 to 13.
In the rotary actuator 1 described above, a rotation angle detection device 60 for detecting the rotation angle of the rotor 11 (corresponding to a rotating body) is mounted in the housing (front housing 18 + rear housing 20). By detecting the rotation angle of the rotor 11 by the rotation angle detection device 60, it is possible to operate the motor 5 at high speed without stepping out.
[0033]
The rotation angle detection device 60 is an incremental encoder, and includes a magnet 61 that rotates integrally with the rotor 11, and a magnetic detection element 62 for magnetic detection (specifically, first to (3 magnetic detecting elements 62A, 62B, 62Z) and a substrate 63 for supporting the magnetic detecting elements 62 in the rear housing 20.
[0034]
The magnet 61 has a substantially ring disk shape, and is joined to the axial end face of the rotor core 14 so as to be arranged concentrically with the rotor shaft 13. When the magnetic force exerted on the magnet 61 from the rotor core 14 is large, the magnet 61 is joined to the rotor core 14 via a non-magnetic film member (not shown).
When the influence of the magnetic force from the rotor core 14 on the magnet 61 is small, the magnet 61 is directly joined to the rotor core 14. As a result, the number of parts can be reduced, and the cost can be reduced.
[0035]
The magnet 61 of this embodiment is made of an inexpensive ferrite plastic magnet, for example, and has a predetermined thickness in the axial direction. The magnet 61 is joined to the rotor core 14 by magnetizing the joining surface of the rotor core 14 and magnetizing the surface on the rotor core 14 side. Of course, instead of joining by magnetic force, joining may be performed by an adhesive or the like.
[0036]
As shown in FIG. 9, a plurality of holes 14 a for magnet positioning are provided on the rear surface of the rotor core 14. On the other hand, a plurality of protrusions 61a are also provided on the joint surface of the magnet 61. Then, by inserting the protrusion 61a of the magnet 61 into the hole 14a of the rotor core 14 and assembling the magnet 61, the magnet 61 is assembled coaxially with the rotation center of the rotor core 14.
[0037]
After the magnet 61 is joined to the rotor core 14, as shown in FIG. 9, a surface (rear surface) facing the magnetic detection element 62 is magnetized for rotational position detection.
This magnetization is performed so that a magnetic force is generated in the axial direction of the magnet 61. By this magnetization, as shown in FIG. Become like
[0038]
Specific magnetization will be described.
As shown in FIG. 10, on the outer peripheral side of the rear surface of the magnet 61, there is provided an outer peripheral magnetized portion 61b in which N poles and S poles are repeatedly magnetized at a pitch of 7.5 degrees. The A-phase and B-phase outputs (FIG. 11) for detecting the precise rotation angle of the rotor 11 from the first and second magnetic detection elements 62A and 62B by repetition of the N pole and the S pole in the rotation direction in the magnetic portion 61b. Reference) is obtained.
[0039]
On the inner peripheral side of the rear surface of the magnet 61, S-poles are magnetized at intervals of 45 degrees, and N-poles are magnetized on both sides in the rotation direction. The Z-phase output (see FIG. 11) for obtaining the synchronization signal of the electric motor 5 from the third magnetic detection element 62Z is obtained by the magnetic pole change at 45-degree intervals in the magnetized portion 61c.
[0040]
Each of the first to third magnetic detection elements 62A, 62B, and 62Z is a Hall IC that includes a Hall element that generates an output according to the amount of magnetic flux passing therethrough, and an amplifier circuit that amplifies the output of the Hall element. In this embodiment, an example in which a Hall IC is used as an example of the magnetic detection element 62 is described. However, an element that detects a change in magnetic flux, such as a Hall element or an MRIC, may be used instead of the Hall IC.
[0041]
The first and second magnetic detecting elements 62A and 62B detect the A phase and the B phase, respectively. The first and second magnetic detecting elements 62A and 62B are arranged on a circumference facing the outer peripheral magnetized portion 61b of the magnet 61, and the outer peripheral magnetized portion 61b. A phase output and B phase output are obtained by the change in magnetic flux.
The third magnetic detecting element 62Z detects the Z phase, is arranged on the circumference facing the inner peripheral magnetized portion 61c of the magnet 61, and outputs the Z phase by a change in magnetic flux of the inner peripheral magnetized portion 61c. Is what you get.
[0042]
Next, the output waveforms of the A-phase, B-phase, and Z-phase by the rotation angle detection device 60 will be described with reference to FIGS.
The A-phase and the B-phase are output signals having a phase difference of 90 degrees in electrical angle. In this embodiment, each time the rotor 11 rotates 15 degrees, the A-phase and the B-phase are output one cycle each. It is configured.
The Z phase is an index pulse that is output once each time the rotor 11 rotates 45 degrees, and the Z phase can define the relative positional relationship between the energized phase of the electric motor 5 and the A and B phases.
[0043]
The substrate 63 supports the first to third magnetic detecting elements 62A, 62B, and 62Z at the positions shown in FIG. 5 in a state facing the magnets 61. As shown in FIGS. A body metal plate 64 (eg, aluminum, stainless steel, etc.) and a film substrate made of an insulating resin material (eg, polyimide, etc.) provided on the surface of the metal plate 64 opposite to the magnet 61 65.
[0044]
On the film substrate 65, a plurality of circuit patterns 65a are formed on a surface that does not touch the metal plate 64 by a printing technique. On the substrate 63, in addition to the first to third magnetic detecting elements 62A, 62B, 62Z, a capacitor 66 for a noise filter and the like are mounted. Each electric component is electrically connected to each circuit pattern 65a. Connected to. On the other hand, an end of each circuit pattern 65a is electrically connected to a terminal terminal (not shown) provided in the rear housing 20. The terminal terminal is connected to the external connection connector.
[0045]
The substrate 63 is supported inside the rear housing 20 so as to be displaceable in the rotation axis direction of the magnet 61 and not to be displaceable in the rotation direction of the magnet 61 and the radial direction of rotation. Details will be described later.
[0046]
(Description of ECU 70)
The ECU 70 will be described with reference to FIG.
The ECU 70 controls the rotation of the electric motor 5 based on range operation means (not shown) operated by the occupant, the rotation angle of the rotor 11 detected by the rotation angle detection device 60, and the like, and is driven via the speed reducer 6. The switching control of the shift range switching device 3 is performed.
[0047]
Here, reference numeral 71 shown in FIG. 3 is a vehicle-mounted battery, reference numeral 72 is a display device (visual display means during normal operation, a warning light, a warning buzzer, etc.) indicating the shift range and the state of the rotary actuator 1, and reference numeral 73. Reference numeral 74 denotes a power supply circuit of the electric motor 5, reference numeral 74 denotes a vehicle speed sensor, and reference numeral 75 denotes a range operation means, a brake switch, and other sensors for detecting a vehicle state. As an example of sensors, a sensor for detecting the rotation angle of the output shaft 17 may be mounted.
[0048]
[Features of the embodiment]
Since the magnetic force emitted by the magnet 61 has a characteristic of decreasing in inverse proportion to the square of the distance, the accuracy of the axial gap A (symbol, see FIG. 1) between the magnet 61 and the magnetic detecting element 62 is equal to the detection accuracy. Becomes very important to enhance
However, when a conventional structure (a structure in which the substrate 63 supporting the magnetic detection element 62 is supported by the rear housing 20) is employed as a support structure for the magnetic detection element 62, there is no space between the magnet 61 and the support structure for the magnetic detection element 62. , The magnet 61 → the rotor core 14 → the rotor shaft 13 → the rear rolling bearing 16 → the rear housing 20 → the support member of the substrate 63 → the substrate 63 → the magnetic detecting element 62. Since many components that disturb the accuracy are interposed, the tolerance of the axial gap A becomes large, which causes deterioration of the detection accuracy.
[0049]
Therefore, as shown in FIG. 1, the rotation angle detection device 60 of this embodiment is provided with the following features to improve the accuracy of the axial gap A between the magnet 61 (magnetic flux emission surface) and the magnetic detection element 62: A substrate supporting means 67 for supporting the substrate 63 supporting the third magnetic detecting elements 62A, 62B, 62Z so as to be displaceable in the direction of the rotation axis of the magnet 61 and not to be displaceable in the direction of rotation of the magnet 61 and the radial direction of rotation. (2) a biasing means 68 for biasing the substrate 63 toward the magnet 61; and (3) a predetermined biasing means disposed between the substrate 63 and the magnet 61 and disposed between the substrate 63 and the magnet 61. And a stopper 69 for forming the axial gap B. FIG. 1 is an enlarged view in a circle of FIG.
[0050]
Next, the above (1) to (3) will be described sequentially.
(1) The substrate support means 67 is provided in the two through holes 67a for positioning (see FIG. 12) formed in the substrate 63 and the rear housing 20 that covers the substrate 63 from the opposite side of the magnet 61. And two positioning pins 67b (see FIGS. 1 and 2) extending in the direction of the rotation axis to be fitted through a minute clearance.
Therefore, the board 63 can be displaced in the axial direction, and cannot be displaced in the rotational direction and the radial direction only by inserting the two through holes 67a of the board 63 into the two positioning pins 67b provided on the rear housing 20. And the substrate 63 is positioned with high precision with respect to the rear housing 20.
[0051]
The substrate 63 has two notches 67c in addition to the two through holes 67a. Each notch 67 c is loosely fitted to the pin extending in the axial direction in the rear housing 20 through a large clearance, and does not contribute to the positioning of the substrate 63.
[0052]
(2) The urging means 68 may be any spring, rubber or the like as long as it urges the substrate 63 toward the magnet 61. In this embodiment, a ring-shaped webbing washer is used. The biasing means 68 (waving washer) biases the substrate 63, which is interposed between the rear housing 20 and the substrate 63 and is supported so as to be displaceable in the axial direction, toward the magnet 61.
[0053]
(3) The stopper 69 is sandwiched between the substrate 63 urged toward the magnet 61 and the rotating magnet 61 to form a predetermined axial gap B between the substrate 63 and the magnet 61. Thus, the axial gap A between the magnet 61 mounted on the substrate 63 and the magnetic detection element 62 is determined.
The stopper 69 of this embodiment has a ring shape and is provided integrally with the magnet 61. As a result, the number of parts can be reduced, parts can be easily managed and assembled, and manufacturing costs can be reduced.
[0054]
Here, means for reducing sliding resistance is provided in a portion that slides and slides between the stopper 69 and the substrate 63.
In this embodiment, at least one surface of the stopper 69 or the substrate 63 that is in sliding contact with the stopper 69 is coated with a high-sliding material (eg, tetrafluoroethylene resin) as a means for reducing the sliding resistance. Things. The stopper 69 may be formed of a high sliding material (for example, ethylene tetrafluoride resin), or the stopper 69 may be formed of a thrust bearing in the rotation direction. Alternatively, a high-sliding material (for example, lubricating oil such as grease or a film such as ethylene tetrafluoride resin) may be interposed between the stopper 69 and the substrate 63.
In addition, by reducing the sliding resistance between the stopper 69 and the substrate 63, the wear of the rotary sliding portion can be prevented and the durability can be increased, and the rotation loss of the motor 5 can be reduced because the rotation loss of the rotor is reduced. Output loss can be suppressed.
[0055]
On the other hand, as shown in FIG. 1, the rotation angle detecting device 60 of this embodiment is provided with a window 63a penetrating a portion of the substrate 63 where the magnetic detecting element 62 is mounted, and the magnetic detecting element 62 The structure which attaches is adopted.
Here, as shown in FIG. 13A, when the magnetic detection element 62 is mounted on the non-magnet side (rear surface) of the substrate 63, the substrate 63 is interposed between the magnetic detection element 62 and the magnet 61. This causes a problem that the detection accuracy is reduced. In addition, since the thickness of the substrate 63 and the thickness of the magnetic detection element 62 are added to the dimension in the axial direction, there is a problem that the rotation angle detection device 60 becomes large in the axial direction.
[0056]
On the other hand, as shown in FIG. 13B, by adopting a structure in which the magnetic detecting element 62 is mounted inside the window 63a formed in the substrate 63, the substrate is provided between the magnetic detecting element 62 and the magnet 61. Since the interposition of the magnet 63 is eliminated, the axial gap A between the magnet 61 and the magnetic detection element 62 can be reduced, and the detection accuracy can be increased.
In the axial dimension, since the thickness of the substrate 63 and the thickness of the magnetic detection element 62 overlap in the axial direction, the rotation angle detection device 60 can be made thin.
As a result, the rotary actuator 1 on which the rotation angle detection device 60 is mounted can be reduced in thickness.
[0057]
[Effects of the embodiment]
As described above, the rotation angle detection device 60 mounted inside the rotary actuator 1 includes a substrate support unit 67 that supports the substrate 63 so as to be able to displace in the axial direction and not to be displaceable in the rotational direction and the radial direction. A biasing means 68 for biasing the substrate 63 toward the magnet 61; a stopper 69 sandwiched between the substrate 63 and the magnet 61 to form a predetermined axial gap B between the substrate 63 and the magnet 61; Is provided.
That is, the axial gap A between the magnet 61 and the magnetic sensing element 62 is determined by the axial tolerance of the stopper 69 and the mounting tolerance of the magnetic sensing element 62 on the substrate 63. As described above, the number of components for determining the tolerance of the axial gap A can be significantly reduced as compared with the related art.
[0058]
Since the number of components that determine the tolerance of the axial gap A between the magnet 61 and the magnetic detection element 62 can be reduced, the tolerance of the axial gap A can be reduced, and the detection accuracy of the rotation angle detection device 60 can be increased.
That is, the tolerance of the axial gap A between the magnet 61 and the magnetic detection element 62 can be reduced at low cost. Further, since the number of components for determining the tolerance of the axial gap A can be reduced, the upper limit of the detection accuracy can be increased.
Thus, the detection accuracy of the rotation angle of the rotor 11 mounted inside the rotary actuator 1 can be improved, and the reliability of the shift range switching device 3 can be improved.
[0059]
(Modification)
In the above embodiment, an example is shown in which the present invention is applied to the rotation angle detection device 60 that detects the rotation angle of the rotor 11 inside the rotary actuator 1 of the shift range switching device 3. The present invention is applicable to a device for detecting a rotation angle, and may be provided so as to detect the rotation angle of a rotating body for other uses.
In the above-described embodiment, the example in which the magnet 61 is joined to the rotor core 14 has been described. However, the partner to which the magnet 61 is joined may be any rotating member, and the magnet 61 is joined to a rotating object other than the rotor core 14 to rotate the magnet 61. May be provided.
[0060]
In the above embodiment, the window 63a is formed in the substrate 63, and the magnetic detection element 62 is disposed inside the window 63a. However, the window 63a is not provided, and the magnetic detection element 62 is opposed to the substrate 63. It may be mounted on the magnet side or the magnet side.
In the above-described embodiment, the example in which the substrate 63 is constituted by the non-magnetic metal plate 64 and the film substrate 65 is shown, but another substrate 63 made of resin or glass may be used.
In the above embodiment, the example in which the stopper 69 is provided integrally with the magnet 61 has been described. However, the stopper 69 may be provided separately from the magnet 61 and the substrate 63, or the stopper 69 may be provided integrally with the substrate 63. May be.
[Brief description of the drawings]
FIG. 1 is a sectional view of a main part of a rotation angle detection device.
FIG. 2 is a sectional view of a rotary actuator.
FIG. 3 is a system configuration diagram of a shift range switching device.
FIG. 4 is a perspective view of a shift range switching device including a parking switching device.
FIG. 5 is a front view of the electric motor.
FIG. 6 is a perspective view of the speed reducer as viewed from a rear side.
FIG. 7 is a perspective view of the speed reducer as viewed from the front side.
FIG. 8 is an exploded perspective view of the speed reducer viewed from the front side.
FIG. 9 is a sectional view of a rotor on which a magnet is mounted.
FIG. 10 is a plan view of a magnet showing a magnetized state.
FIG. 11 is an output waveform diagram of A, B, and Z phases when the rotor rotates.
FIG. 12 is a plan view of the substrate as viewed from the rear side.
FIG. 13 is a cross-sectional view of a main part of the substrate, showing a state where the magnetic detection element is mounted.
[Explanation of symbols]
5 Electric motor
11 rotor (rotating body)
14 Rotor core
20 Rear housing (housing that covers the substrate from the opposite side of the magnet)
60 Rotation angle detector
61 magnet
62 Magnetic sensing element
63 substrate
63a window
67 Substrate support means
67a Through hole for positioning
67b Positioning pin
68 biasing means
69 Stopper
A axial gap (axial gap between magnet and magnetic sensing element)
B axial gap (axial gap between magnet and substrate)

Claims (6)

A magnet that rotates together with the rotating body and changes the magnetic pole in the direction of rotation,
A magnetic detection element for detecting magnetism,
A substrate for supporting the magnetic detection element,
In a rotation angle detection device that detects a rotation angle of the rotating body by detecting magnetism emitted from the magnet with the magnetic detection element,
A substrate supporting means that supports the substrate so that it can be displaced in the axial direction, and cannot be displaced in the rotational direction and the radial direction,
Urging means for urging the substrate toward the magnet,
A stopper that is interposed between the substrate and the magnet and forms a predetermined axial gap between the substrate and the magnet;
A rotation angle detection device comprising: The rotation angle detection device according to claim 1,
The rotation angle detecting device, wherein the stopper is provided integrally with one of the housing, the magnet, and the substrate to which the substrate is attached. The rotation angle detection device according to claim 1 or 2,
A rotation angle detecting device, wherein means for reducing sliding resistance is provided in a portion that slides on the stopper. The rotation angle detection device according to any one of claims 1 to 3,
The rotation angle detection device, wherein the substrate has a window portion penetrating a portion where the magnetic detection element is mounted, and the magnetic detection element is mounted in the window portion. The rotation angle detection device according to any one of claims 1 to 4,
The substrate supporting means,
Two positioning through holes formed in the substrate;
A rotation angle detecting device, comprising: two positioning pins provided in a housing that covers the substrate from the opposite side of the magnet and that are fitted into the through holes via minute clearances and that extend in an axial direction. The rotation angle detection device according to any one of claims 1 to 5,
The rotating body is a rotor in a rotating machine such as an electric motor or a generator,
The rotation angle detecting device, wherein the magnet is provided so as to be joined to a rotor core constituting the rotor.

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