JP2009063443A - Rotation angle detecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To protect a resin sealing part without having to provide a cover member while reducing the time and labor required for a resin sealing operation of a circuit substrate to be incorporated in a rotation angle detecting apparatus. <P>SOLUTION: A shaft 2 is combined to a housing 1 and rotation-freely supported by bearings 4 and 5. A housing lid 6 is bolted to one side end of the housing 1 to provide preload. A rotation angle sensor 3 is constituted of only a magnetic encoder. Prior to the bolting of the housing lid 6, the circuit board 32 to which a sensor integrated circuit 31 is mounted is screwed to a recession part 62 of the housing 6, and a resin 34 is inserted in the recession part 62 to seal it. The recession part 62 is formed in such a way as to be positioned more closely to the center side than an outer circumferential part 61 to be in contact with the one side end of the housing 1. A resin sealing part formed in the recession part 62 is positioned in an internal space formed by the housing 1 and the housing lid 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotation angle detection device including a shaft that is rotatably supported with respect to a housing, and a rotation angle sensor that detects a rotation angle of the shaft.

In this type of rotation angle detection device, a rolling bearing is incorporated between the inner periphery of the housing and the shaft. A housing lid that covers the bearing mounting opening that opens to one side of the housing can be attached to one end of the housing. When the housing lid is attached, an internal space is formed by the housing and the housing lid. The internal space is used for the arrangement of the rotation angle sensor, and the rotation angle sensor can be protected from external force by using the housing and the housing lid.
This type of rotation angle detection device can previously attach the circuit board to the housing lid and perform wiring, can also install the circuit board using the side area of the housing lid, and rolls the shaft. If the housing lid is attached while being supported by the bearing, there is an advantage that the positional relationship between the rotation angle sensor and the shaft can be determined.

Conventionally, as a rotation angle sensor that can be incorporated as described above, a contact-type angle potentiometer has been widely used (Patent Document 1).
The brush of the angle potentiometer is attached to one end face of the shaft. An annular resistor and an electrical piece to be brought into contact with the brush are fixed on the base. The base is attached to a portion of the other side surface of the housing lid facing the one end surface of the shaft by adhesion. When the housing lid is mounted while the shaft is supported by the bearing, the brush, the resistor, and the electrical piece come into contact with each other, thereby forming a detection circuit that converts the rotation angle into an electrical signal.
On the other hand, a recess for accommodating the circuit board is formed on one side of the lid. By storing the circuit board in the recess, resin sealing of the circuit board is possible. The circuit board is configured in advance as an AD converter that digitizes the analog detection signal of the angle potentiometer. Note that a power supply circuit is appropriately provided on the circuit board.
The other end of the shaft is exposed to the outside through a shaft through hole formed on the other side surface of the housing. It is possible to connect to the shaft of another device at the exposed portion of this shaft.
The detection signal digitized by the circuit board is transmitted to an external computer, and arithmetic processing is performed by the external computer.

  The rotation angle detection device disclosed in the above-mentioned Patent Document 1 has a contact-type detection circuit and a circuit board separately arranged on both sides of the housing lid, so that water or oil can reach the charging part of the circuit board with a resin seal. While preventing the failure, it is possible to reliably eliminate the possibility that the resin adheres to the resistor or the electrical piece when the circuit board is sealed with the resin, thereby causing a detection failure.

JP-A-11-344302 (abstract)

In the rotation angle detection device of the above-mentioned Patent Document 1, the resin sealing portion is exposed to the outside. For example, when the rotation angle detection device is used to detect the angle of the shaft of a construction machine, the resin has an external force such as vibration or impact. There is a concern of damage due to damage. In particular, when a semi-solid resin such as urethane resin is used, the vibration of the element mounted on the circuit board can be reduced due to its flexibility, but the resin itself is weak against external force, so Resin sealing is easily broken.
If the circuit board is covered with a cover member instead of resin sealing or the resin sealing portion is covered with a cover member, a separate cover member is required and the number of components increases. Moreover, the installation space of a cover member may not be obtained.

  In addition, the rotation angle detection device of Patent Document 1 described above connects the contact points of the resistor and the electrical piece to the circuit board unless the base on which the resistor and the electrical piece are fixed is attached to the other side of the housing lid. Can not do it. That is, it is troublesome to turn over the housing lid to which the base is attached and to separately seal the circuit board with resin. If the circuit board and the substrate are arranged on the same side surface of the housing lid, a detection failure may occur due to resin sealing.

  In view of the above circumstances, an object of the present invention is to protect a resin sealing portion without providing a cover member while reducing the labor of resin sealing work for a circuit board incorporated in a rotation angle detection device.

The present invention that solves the above-mentioned problems includes a shaft that is rotatably supported with respect to the housing, and a rotation angle sensor that detects a rotation angle of the shaft, and a bearing installation port is provided at one end of the housing. Rotation angle detection in which a housing cover can be mounted, a recess is formed in the side of the housing cover, a circuit board for processing the detection signal of the rotation angle sensor is housed in the recess, and the circuit board is sealed with resin In the apparatus, the rotation angle sensor is composed only of a magnetic encoder, and an outer peripheral portion is formed on the other side of the housing lid so as to contact one side end of the housing, and the concave portion is positioned on the center side from the outer peripheral portion. It is characterized by being formed.
Here, the rotation angle sensor composed of a magnetic encoder has a plurality of magnetic detection elements that output analog detection signals in accordance with changes in magnetic flux caused by rotation of an encoder that rotates integrally with a shaft. The elements are arranged so as to obtain an analog detection signal having a phase difference between a pair of magnetic detection elements, and the rotation angle is obtained by an arithmetic processing circuit based on the analog detection signal having the phase difference. It is a general one. The arithmetic processing circuit is mounted on the circuit board.

Specifically, an outer peripheral portion that contacts one side end of the housing is formed on the other side surface of the housing lid, and the housing lid is attached to the housing by forming the concave portion so as to be positioned on the center side of the outer peripheral portion. The resin sealing portion is positioned in an internal space formed by the housing and the housing lid in a state of being attached to one end of the housing, and is protected from the outside by the housing and the housing lid.
Since the plurality of magnetic detection elements of the rotation angle sensor are opposed to the magnetized surface of the encoder that rotates integrally with the shaft, like the concave portion, the magnetic detection elements are arranged on the center side of the outer peripheral portion of the other side surface of the housing lid. Become. That is, since the plurality of magnetic detection elements and the circuit board are arranged on the same side surface of the housing lid, there is no need to turn over the housing lid when resin-sealing the circuit board housed in the recess, and the resin sealing of the circuit board is eliminated. The labor of stopping work is reduced.
Even when the resin is attached to the magnetic sensing surface of the magnetic detection element, the lines of magnetic force pass through the resin, so that there is no problem in detection. Therefore, if the rotation angle sensor is composed only of a magnetic encoder, there is no possibility of detection failure due to resin sealing.

As the rotation angle sensor, a sensor having a sensor integrated circuit in which a plurality of magnetic detection elements and an analog arithmetic processing circuit are packaged is preferably adopted. By mounting the sensor integrated circuit on the circuit board, the magnetic detection element and the circuit board can be mounted and resin-sealed at a time.
In addition, since this type of sensor integrated circuit performs arithmetic processing with an analog arithmetic processing circuit, it is not a relatively large-scale circuit such as an AD converter, but is compactly integrated with a plurality of magnetic detection elements. The installation area of the circuit board is small, and the downsizing of the concave portion is facilitated. In addition, this kind of sensor integrated circuit is variously prepared as a commercial item, and has an advantage that it is easy to procure.
Instead of the sensor integrated circuit described above, it is possible to adopt a rotation angle sensor in which a plurality of magnetic detection elements and an analog arithmetic processing circuit are separately mounted.

It is possible to adopt a configuration in which a rolling bearing is incorporated between the housing and the shaft, and the outer peripheral portion of the lid is pressed against one side surface of the outer ring of the rolling bearing to apply preload. Pre-load increases the rigidity of the rolling bearing and prevents shaft runout, thereby preventing relative displacement between the magnetic detection element and the encoder.
When this configuration is adopted, if the other side surface of the housing lid is formed in a radial plane, the space between the one end surface of the shaft and the housing lid becomes narrow, and there is insufficient space for placing the rotation angle sensor. A spacer ring is interposed between the two.
Here, as described above, the concave portion is located on the center side from the outer peripheral portion that presses one side surface of the outer ring.
Therefore, if the configuration in which the concave portion is recessed in the axial direction from the outer peripheral portion so that the bottom surface thereof faces the one end surface of the shaft in the axial direction is adopted, the rotation angle sensor is utilized by using the formation of the concave portion. The space for disposing the spacers can be increased, and the spacer ring can be omitted or the spacer ring can be reduced in width.

  In addition, by placing resin in the concave portion lower than the magnetic sensing surface of the magnetic detection element of the rotation angle sensor, the magnetic gap between both surfaces can be made smaller because there is no resin between the magnetized surface of the encoder. As a result, a smaller magnetic detection element or encoder can be employed.

  As described above, the resin-sealed circuit board is located in the internal space formed by the housing and the housing lid. For this reason, the circuit board is double protected from external water and oil. Even if a resin that is semi-solidified is used as the resin, the resin sealing portion is protected by the housing and the housing lid, and therefore is not easily destroyed.

  As the resin to be semi-solidified, in addition to urethane resin, foamed urethane resin, silicon resin, or the like can be used.

  As described above, according to the present invention, the rotation angle sensor includes only a magnetic encoder, the arithmetic processing circuit for the rotation angle sensor is provided on the circuit board, and one side end of the housing is provided on the other side of the housing lid. By adopting a configuration in which the outer peripheral portion to be contacted is formed and the concave portion is formed so as to be positioned at the center side from the outer peripheral portion, the cover for the circuit board incorporated in the rotation angle detecting device is reduced while reducing the labor of resin sealing. The resin sealing portion can be protected without providing a member.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall configuration of a rotation angle detection device according to an embodiment of the present invention by an axial plane cut surface.
As shown in FIG. 1, the rotation angle detection device according to this embodiment includes a shaft 2 that is rotatably supported with respect to the housing 1, and a rotation angle sensor 3 that detects the rotation angle of the shaft 2. Roller bearings 4 and 5 are assembled between the housing 1 and the shaft 2 so as to form a combined bearing, and a housing lid 6 covers a bearing incorporation port that opens to one side of the housing 1 at one end of the housing 1. Can be installed.

  The housing 1 has a mounting flange 11 on the outer periphery, and can be screwed to a housing of another device in a state where the rotation angle detection device is assembled. The other end surface of the shaft 2 is exposed from a shaft opening formed on the other side surface of the housing 1 and can be connected to a shaft of an external device.

  The rotation angle sensor 3 is composed only of a magnetic encoder.

  The rolling bearings 4 and 5 are sealed bearings, and the lubricant is prevented from scattering inside the rotation angle sensor housing 1. The rolling bearings 4 and 5 are ball bearings in consideration of rotational inertia resistance.

  On the other side surface of the housing lid 6, there are an outer peripheral portion 61 applied to one side end of the housing 1, and a concave portion 62 that is located on the center side of the outer peripheral portion 61 and is recessed toward the one axial side from the outer peripheral portion 61. Is formed.

  In a state in which the shaft 2 is rotatably supported by the rolling bearings 4 and 5 with respect to the housing 1, the outer peripheral portion 61 of the housing lid 6 hits one end of the housing 1, and the rolling bearing on the housing lid 6 side. It also hits one side of the outer ring of 5. The housing lid 6 is fixed by fastening its outer peripheral portion 61 to the housing 1 with bolts 7. Here, the recessed portion 62 of the housing lid 6 is recessed so that the bottom surface thereof faces the one end surface of the shaft 2 in the axial direction in this fixed state. Thereby, the opposing space | interval of the housing cover 6 and the one side surface of the axis | shaft 2 is expanded by the recessed part 62, and the internal space for arrange | positioning the rotation angle sensor 3 is ensured, without using a spacer ring.

  Further, when the outer peripheral portion 61 of the housing lid 6 is pressed against one side end of the housing 1 with the bolt 7, the outer peripheral portion 61 of the housing lid 6 is pressed against the entire circumference of one side surface of the outer ring of the rolling bearing 5. A fixed position preload is applied to the rolling bearings 4 and 5 by the shoulder 12 of the housing 1, the spacer 21 of the shaft 2, and the housing lid 6. Thereby, the rigidity of the rolling bearings 4 and 5 is increased, and the shaft 2 is prevented from running out.

  The outer peripheral portion 61 of the lid 6 and the housing 1 are sealed with a packing 8. A space between the shaft opening of the housing 1 and the shaft 2 is sealed with an oil seal 9a and a slinger 9b.

  The rotation angle sensor 3 includes a sensor integrated circuit 31 in which an arithmetic processing circuit including a plurality of magnetic detection elements 31a and 31b and an analog arithmetic processing circuit is packaged. As the sensor integrated circuit 31, one having an analog arithmetic processing circuit for obtaining a rotation angle from the sine wave output and the cosine wave output of these magnetic detection elements, for example, one disclosed in Japanese Patent Application Laid-Open No. 2004-191101 is used. Can do.

  The sensor integrated circuit 31 is mounted on the circuit board 32. One end of the input / output line 33 is connected to the circuit board 32. The other end of the input / output line 33 is connected to an external device.

  The circuit board 32 on which one ends of the sensor integrated circuit 31 and the input / output line 33 are fixed is housed in a recess 62 formed on the other side of the housing lid 6. The circuit board 32 is supported by screwing it to the bottom surface of the recess 62 so that the plate surface is along the radial plane. This is because the magnetic sensing surfaces of the magnetic detection elements 31a and 31b are directed in the axial direction. Note that the magnetic sensing surfaces of the magnetic detection elements 31a and 31b are flush with the mold plane formed at the other axial end of the sensor integrated circuit 31. In the case where the housing lid 6 has conductivity, the plate surface of the circuit board 32 and the bottom surface of the recess 62 may be insulated.

  The circuit board 32 can be screwed with the other side of the housing lid 6 facing up. The resin substrate 34 can be put into the recess 62 and the circuit board 32 can be sealed while keeping the housing lid 6 in the posture for screwing. A urethane resin is used as the resin 34. The sensor integrated circuit 31 is completely buried in the resin 34, and the vibration of the sensor integrated circuit 31 is reduced by the flexibility of the resin 34, thereby preventing the soldered portion of the circuit board 32 from being broken.

  A through hole 63 facing the plate surface of the circuit board 32 screwed to the recess 62 is formed in the housing lid 6, and the input / output line 33 is connected to the outside from the through hole 63 when the circuit board 32 is screwed. It is taken out.

  The encoder 35 of the rotation angle sensor 3 is composed of a magnetic drum in which N poles and S poles are alternately magnetized in the circumferential direction, and is mounted on the one end face of the shaft 2 so that the center of rotation coincides with the shaft 2. It is supported by the shaft 2 by being fixed with. In addition, the one side end surface of the shaft 2 is formed in a radial plane for simplification of the shape, and the encoder 35 is supported on the one side end surface of the shaft 2 by a fixture.

  When the encoder 35 is fixed to the shaft 2 and the housing lid 6 to which the circuit board 32 is fixed is pressed against the one end of the housing 1 in the axial direction with the bolt 7, the magnetic sensing surfaces of the magnetic detection elements 31a and 31b are 90 °. The phase difference is fixed in a positional relationship facing the magnetized surface of the encoder 35 in the axial direction.

The rotation angle detection device according to this embodiment has the above-described configuration. After screwing the circuit board 32 on which the sensor integrated circuit 31 is mounted in advance into the recess 62 of the housing lid 6, the resin sealing is performed as it is. be able to. For this reason, the rotation angle detection device according to this embodiment does not require the trouble of turning over the housing lid 6, and can reduce the work of resin sealing of the circuit board 32.
The through hole 63 is closed with a filler after the housing lid 6 is attached to the housing 1 and the initial calibration work of the rotation angle sensor 3 is completed. This is because when there is an initial failure of the rotation angle sensor 3, filling of the through hole 63 is wasted. Therefore, when the through hole 63 is formed, the trouble of turning the housing lid 6 over is not increased.

  Further, in the rotation angle detection device according to this embodiment, the resin sealing portion formed in the recess 62 is formed by the housing 1 and the housing lid 6 in a state where the housing lid 6 is mounted on one side end of the housing 1. Since it is located in the internal space, it can be protected from the outside by the housing 1 and the housing lid 6.

  In this embodiment, in order to give priority to protection of the sensor integrated circuit 31, the sensor integrated circuit 31 is buried in the resin 34. However, as shown in FIG. 62, by depositing the resin 34 lower than the magnetic sensing surfaces of the magnetic detection elements 31a and 31b, the magnetic gap between the two surfaces can be made smaller because there is no resin between the magnetic surface of the encoder 35, As a result, a smaller magnetic detection element or encoder can be employed. Of course, for the purpose of resin sealing, the resin 34 is deposited so as to bury all the charging parts of the circuit board 32.

Sectional drawing which shows the whole structure of embodiment Sectional drawing which shows another resin sealing aspect of embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Shaft 3 Magnetic encoder 4, 5 Rolling bearing 6 Lid 7 Bolt 8 Packing 9a Oil seal 9b Slinger 11 Mounting flange 12 Shoulder 31 Sensor integrated circuit 31a, 31b Magnetic detection element 32 Circuit board 33 Input / output line 34 Resin 35 Encoder 61 Outer peripheral part 62 Recessed part 63 Through hole

Claims (5)

  A shaft that is rotatably supported with respect to the housing and a rotation angle sensor that detects a rotation angle of the shaft, and a housing lid that covers a bearing installation port can be attached to one end of the housing. In a rotation angle detection device in which a concave portion is formed on a side surface of the lid, a circuit board for processing the detection signal of the rotation angle sensor is accommodated in the concave portion, and the circuit board is sealed with a resin. It is composed only of an encoder, and an outer peripheral portion is formed on the other side surface of the housing lid so as to be in contact with one end of the housing, and the concave portion is formed so as to be located on the center side from the outer peripheral portion. Rotation angle detector.   The rotation angle detection device according to claim 1, wherein the rotation angle sensor includes a sensor integrated circuit in which a plurality of magnetic detection elements and an analog arithmetic processing circuit are packaged, and the sensor integrated circuit is mounted on the circuit board.   A rolling bearing is incorporated between the housing and the shaft, the outer peripheral portion of the lid is pressed against one side surface of the outer ring of the rolling bearing to give a preload, and the concave portion has a bottom surface on one side end surface of the shaft. The rotation angle detection device according to claim 1, wherein the rotation angle detection device is recessed toward the one axial side from the outer peripheral portion so as to face the axial direction.   The rotation angle detection device according to any one of claims 1 to 3, wherein a resin is deposited in the concave portion lower than a magnetic sensitive surface of a magnetic detection element of the rotation angle sensor.   The rotation angle detection device according to any one of claims 1 to 4, wherein a semi-solid resin is used as the resin.

Images