JP2009276241A - Rotational angle detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain backlash in a follower gear with a simple structure having a small number of components. <P>SOLUTION: The rotational angle detector 10 includes a holder 30 made of a synthetic resin in the inside in addition to a cover 20 and a case 40 molded by a metal plate for composing a housing. Also, the rotational angle detector 10 includes: a main drive gear 12 made of a synthetic resin integrally rotating with a detection target, such as a steering shaft; and two follower gears 14 made of a synthetic resin rotating following the rotation while mating with the main drive gear 12. While the follower gear 14 is being sandwiched by the holder 30 and the case 40, the follower gear 14 is supported rotatably by respective support sections 38, 42. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotation angle detection device suitable for detecting, for example, a rotation angle of a steering shaft of a vehicle as an absolute angle.

  This type of rotation angle detection device is suitable for use in detecting the rotation angle of a steering shaft rotated by a driver's steering operation as an absolute angle, for example, with respect to vehicle attitude control technology. In general, the rotation angle is detected by calculating the absolute angle from the phase difference of rotation generated between a plurality of driven gears meshing with the main driving gear while rotating the main driving gear integrally with the rotation of the steering shaft. The calculation method is adopted. When detecting the rotation angle, the driven gear is particularly required to rotate with a low torque and without a load. Therefore, a certain clearance is required between the driven gear and its bearing portion. However, when such a clearance is provided, there are problems that the driven gear rattles in the axial direction when the vehicle is traveling, and the detection accuracy is lowered, or abnormal noise is generated due to vibration.

  For this reason, there is conventionally known a prior art in which the driven gear is elastically pressed in the axial direction to suppress the occurrence of rattling and vibration noise during traveling (see, for example, Patent Document 1). In this prior art, a driven gear having a magnet provided at the center is accommodated in a case member, and a bearing recess is formed on the inner surface of the case member so that the driven gear is rotatably supported at one end thereof. . In the case member, a circuit board is disposed at a position opposite to the magnet on the other end side of the driven gear, and a magnetic change detecting element for detecting a change in the magnetic field is mounted on the circuit board. In particular, in the prior art, a spring member is installed between the case member and the driven gear on one end side of the driven gear, and the driven gear is pressed against the circuit board by its elastic force.

According to the above prior art, the driven gear can be rotated with low torque while suppressing rattling and vibration of the driven gear even if there is a clearance between the bearing recess and the circuit board and the driven gear. It is thought that you can.
Japanese Patent Laying-Open No. 2004-279265 (page 4-5, FIGS. 1 and 4)

  However, since the prior art technique requires another spring member only for pressing the driven gear, there is a problem that the number of parts increases and the structure becomes complicated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a rotation angle detection device that can suppress rattling of a driven gear with a simple structure with a small number of parts.

In order to solve the above problems, the present invention employs the following solutions.
That is, the present invention relates to a main driving gear that rotates by being directly or indirectly connected to a detection object that rotates about a predetermined axis, a driven gear that rotates by meshing with the main driving gear, and a central portion of the driven gear. And a first support portion that rotatably supports the main driving gear and rotatably supports the driven gear through the insertion hole. A holder member in which an opening facing the magnet is formed in a state where the driven gear is supported by the first support portion, and a second insertion hole formed so that a detection object can be inserted, A first cover member that is rotatably attached to the holder member from one side thereof so that the main driving gear and the driven gear are rotatably sandwiched between the holder member and a magnet installed through the opening on the other side of the holder member Opposing magnetic sensing element A second circuit board having a circuit board mounted between the holder member and the mounted circuit board and a third insertion hole formed so that a detection object can be inserted is attached to the holder member from the other side. And a main gear, a driven gear, and a holder made of synthetic resin, and at least the first cover member formed of a metal plate.

  According to the rotation angle detection device of the present invention, the main driving gear and the driven gear rotate while contacting the synthetic resin holder on one side and contacting the first metal cover member on the other side. Therefore, it can rotate with a small frictional resistance as compared with a configuration in which both sides of the main driving gear and the driven gear rotate in contact with the synthetic resin member. Therefore, since the main driving gear and the driven gear can be sandwiched between the holder member and the first metal cover member, rattling and vibration of the driven gear can be suppressed with a simple structure with a small number of parts. it can. Further, wear due to friction between the main driving gear and the driven gear and the first cover member can be reduced, and the main driving gear and the driven gear can be smoothly rotated.

  Further, the rotation angle detection device of the present invention may be an embodiment in which the second cover member is formed from a metal plate. In this case, since the thickness (thickness) of the material can be reduced as compared with the case where the second cover member is formed of a synthetic resin material, the thickness of the rotation angle detection device can be reduced. As a result, it is possible to contribute to an improvement in the size of the mechanical parts such as the main driving gear and the driven gear and the degree of freedom of arrangement.

  The metal plate is preferably made of stainless steel. With such a configuration, even if the plate thickness is thin, mechanically high strength can be maintained, and when the first and second cover members are both metal plates made of stainless steel, the use environment of the rotation angle detection device (for example, a vehicle) The influence of the external magnetic field can be cut off around the steering post), and the detection accuracy by the magnetic detection element can be stably maintained.

  The rotation angle detection device of the present invention has a configuration in which the main driving gear and the driven gear made of synthetic resin are sandwiched between the holder made of synthetic resin and the first cover member formed from a metal plate, so the number of parts is small With a simple structure, rattling and vibration of the driven gear can be suppressed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a rotation angle detection device 10 according to an embodiment. The rotation angle detection device 10 is suitable for use as a steering angle sensor that detects, for example, the rotation angle of a steering shaft of a vehicle as a detection object that rotates about a predetermined axis CL as an absolute angle.

  For this reason, the rotation angle detecting device 10 has an insertion hole 10a formed through the center thereof in the thickness direction. A steering column (not shown) is inserted in a state where a steering shaft (not shown) is inserted into the insertion hole 10a. It is attached to the rotary connector attached to the stator member. The rotary connector is an electrical connection between the handle side and the vehicle body side, and the flat cable is stored in a storage space formed between the movable housing connected to the handle and the stator member and fixed to the fixed housing.・ Wound. In the rotation angle detection device 10, the second cover member (cover) 20, the first cover member (case) 40, and the holder member (holder) 30 are integrated by snap coupling. The cover 20 and the case 40 are assembled so as to face each other in the thickness direction (in the direction of the axis CL) from both sides in a state where the holder 30 is arranged in the middle. The rotary connector is laminated so as to be in contact with the case 40 side and integrated with the rotation angle detection device 10.

  The insertion hole 10a is configured by the cam rotor 50 and the main gear 12 that are snap-coupled. The cam rotor 50 and the main drive gear 12 rotate about the axis CL with respect to the cover 20, the case 40 and the holder 30. In the cam rotor 50, a cancel cam 50a protrudes outward along the central axis CL. The cancel cam 50a can be used as a mechanism component for returning the turn signal switch (not shown) to the neutral (OFF) position when the left or right operation (ON) is performed.

  Further, at one end of the main drive gear 12, a connecting portion 12d is formed so as to protrude in a direction opposite to the direction in which the cancel cam 50a protrudes, that is, in the direction toward the outside from the case 40. The connecting portion 12d is fitted into a recess formed in a movable housing of a rotary connector (not shown). Therefore, the main drive gear 12 is connected to the handle connected to the steering shaft via the movable housing of the rotary connector, so that it is indirectly connected to the steering shaft and rotates as the handle rotates.

  Further, a connector 20a protrudes from the outer surface of the cover 20, and the rotation angle detection device 10 is connected to an electronic control unit (on-vehicle ECU) (not shown) via the connector 20a. A plurality of pin insertion holes 20 b are arranged in the upper position of the cover 20. These pin insertion holes 20b are inserted with contact probes when the electrical characteristics are inspected or software is written in a built-in device after the rotation angle detector 10 is assembled. In addition, after completion | finish of a test | inspection etc., the pin insertion hole 20b is closed by label sticking which is not illustrated, for example.

  Next, FIG. 2 is a perspective view showing the rotation angle detection device 10 disassembled into main components. Hereinafter, main components of the rotation angle detection device 10 will be described.

[Mechanical component elements]
The rotation angle detection device 10 includes a main driving gear 12 and two driven gears 14 in addition to the cover 20, the case 40, the holder 30, and the like.

[Main drive gear]
The main drive gear 12 made of synthetic resin is provided with an insertion hole 12a passing through the center thereof. The insertion hole 12 a constitutes a part of the insertion hole 10 a of the rotation angle detection device 10. When the rotation angle detection device 10 is attached to a rotation connector (not shown), a steering shaft (detection target) (not shown) is inserted into the through hole 12a of the main driving gear 12, and in this state, the steering shaft is indirectly connected to the steering shaft. The main drive gear 12 thus rotated rotates. The main drive gear 12 has two-stage gears 12b and 12c having different numbers of teeth.

[Driven gear]
The two driven gears 14 made of synthetic resin are composed of gears having the same number of teeth, and rotate according to the rotation of the driven gears 14 while meshed with the main driving gear 12. The two driven gears 14 are meshed with the gears 12b and 12c of each stage of the main driving gear 12, respectively. One side of each driven gear 14 has a first holding portion 14b formed with a storage portion 14a for storing the magnet 16 in the center thereof, and a pressing projection 14c is outwardly formed on the periphery of the storage portion 14a. It protrudes (Figs. 3 and 4). Therefore, when the magnet 14 is stored in the storage portion 14a and the heating body is pressed against the pressing projection 14d, the pressing projection 14d is deformed to suppress the magnet 14, and can be reliably fixed in the storage portion 14c. . Further, the other side of each driven gear 14 has a second holding portion 14e having a recess 14d formed in the center thereof. The recess 14 d is fitted with a protruding portion 42 that slightly protrudes from the inner surface of the case 40 described later toward the holder 30.

〔magnet〕
A magnet 16 is attached to each driven gear 14 (FIG. 6). The magnet 16 is installed in the storage portion 14a of the driven gear 14 with one end face side exposed.

[Holder member]
An insertion hole 30a is formed in the holder 30 made of synthetic resin, and the holder 30 can rotatably support the main driving gear 12 in the insertion hole 30a.

  The holder 30 is formed with a support portion 30b that rotatably supports the two driven gears 14. As shown in FIG. 6, on one side of the holder 30, that is, the surface facing the inner surface of the case 40, each support portion 30b is formed into a hollow shape having a substantially circular cross section, and each support portion 30b is In the state where the driven gear 14 is mounted in the recess, it can be rotatably supported. As shown in FIG. 2, a protrusion 32 slightly protruding toward the inner surface of the cover 20 is formed on the other surface of the holder 30 corresponding to each support portion 30 b.

  The holder 30 is formed with a circular opening 30d on the inner bottom surface of each support portion 30b. These openings 30d penetrate the holder 30 in the thickness direction, and the openings 30d are positioned so as to face the rotation regions of the magnets 16 in a state where each driven gear 14 is mounted on the support portion 30b. .

[First cover member]
The case 40 is formed by pressing a thin stainless steel plate (thickness less than 1 mm), for example. A circular insertion hole 40a as a second insertion hole is formed in the center of the case 40, and the insertion hole 40a constitutes a part of the insertion hole 10a.

  A projecting portion 42 having a circular cross section is formed on the inner surface of the case 40, that is, the surface facing the holder 30, corresponding to each of the two driven gears 14 (FIGS. 2 and 6). Each projecting portion 42 slightly protrudes from the inner surface of the case 40 toward the holder 30, and can be inserted into the recessed portion 14 d of the driven gear 14 to rotatably support the driven gear 14. In the rotation angle detection device 10, the case 40 is combined with the holder 30, and the driven gear 14 is sandwiched between the support portion 30 b of the holder 30 and the support portion 42 of the case 40 on one side and the other side. Supported.

  An annular sliding surface 46 is formed on the inner surface of the case 40 around the insertion hole 40a. The sliding surface 46 can be smoothly rotated while being in contact with the other end surface of the main driving gear 12.

[Circuit board]
A circuit board 70 is attached to the other side of the holder 30. The circuit board 70 is also formed with an insertion hole 70a at the center. The connector 20a is mounted on the circuit board 70.

[Magnetic detection element]
In the state where the circuit board 70 is attached to the holder 30, the two magnetic sensors 72 are attached to the circuit board 70 so as to face the magnet 16 through the opening 30 d. Therefore, when the magnet 16 rotates together with each driven gear 14, each magnetic field change is detected by each magnetic sensor 72. In the present embodiment, for example, a GMR (Giant Magneto-Resitive) sensor is used as the magnetic sensor 72. In addition, the circuit board 70 is mounted with a microprocessor (not shown), peripheral devices such as a memory device and I / O, and these are connected through a predetermined wiring pattern.

[Cover member]
The cover 20 is attached to the holder 30 so as to cover the circuit board 70. The cover 20 is also formed by pressing a thin stainless steel plate (thickness less than 1 mm), for example. As shown in FIG. 6, an insertion hole 20 a as a third insertion hole is formed in the center of the cover 20, and this insertion hole 20 a constitutes a part of the insertion hole 10 a of the rotation angle detection device 10. At the same time, it becomes a fitting portion for attaching the inner cylinder portion 50a of the cam rotor 50 (see FIG. 1). Further, a rectangular insertion hole 24 is formed in the cover 20 so as to allow the connector 20a to be inserted.

  The holder 30 is attached to the main driving gear 12 and the driven gear 14 by fitting. The cover 20, the holder 30, and the case 40 are attached to each other by screwing, and the circuit board 70 is also attached to the holder 30 by screwing.

  For this reason, the cover 20 is formed with screw insertion holes 22 at the peripheral edge thereof, and the holder 30 is also formed with screw insertion holes 34 at corresponding positions. Each case 40 has a female screw portion 44 at a corresponding position. In the completed state of the rotation angle detection device 10, each screw is inserted into the female screw portion 44 of the case 40 in a state where screws (not shown in the drawing) are inserted into the screw insertion holes 22 and 34 of the cover 20 and the holder 30. It is screwed on.

  In addition, screw insertion holes 74 are formed in the circuit board 70, and screw insertion holes 36 are also formed in the holders 30 at corresponding positions. Each case 40 has a female screw portion 44 at a corresponding position. In a completed state of the rotation angle detection device 10, each screw is a female screw portion 44 of the case 40 in a state where screws (not shown in the drawing) are inserted through the screw insertion holes 74 and 36 of the circuit board 70 and the holder 30. Is screwed to.

  FIG. 3 is an exploded perspective view showing the relationship among the holder 30, the main driving gear 12, the driven gear 14, and the magnet 16. The magnet 16 is formed in a square ring shape. Each driven gear 14 is formed with a mounting portion 14a of a magnet 16 at the center. The mounting portion 14a has a hollow with a square cross section that can accommodate the magnet 16. Further, two fixing projections 14b are formed on the peripheral edge portion of the attachment portion 14a so as to face each other. In this embodiment, the magnet 16 is fixed to the driven gear 14 by fitting the magnet 16 into the mounting portion 14a and thermally deforming the heating member against the fixing member 14b. Further, when the magnet 16 is fixed to the driven gear 14, the magnet 16 is exposed to one end face side of the driven gear 14.

  In the completed state of the rotation angle detection device 10, the main driving gear 12 is rotatably supported in a state of being fitted into the insertion hole 30 a of the holder 30. Each driven gear 14 is supported by a support portion 30 b (FIG. 6) of the holder 30. The inner diameter of the opening 30d is set larger than the outer dimension (diagonal dimension) of the magnet 16. For this reason, in the state which the driven gear 14 was assembled | attached to the holder 30, the magnet 16 can be visually recognized in the opening 30d.

  FIG. 4 is an enlarged perspective view showing the meshing state of the main driving gear 12 and the driven gear 14. The main drive gear 12 is composed of two-stage gears 12b and 12c having different numbers of teeth. In the completed state of the rotation angle detecting device 10, the two driven gears 14 are engaged with the gears 12b and 12c at each stage. It is attached with. Although the number of teeth of the two driven gears 14 is the same, a phase difference occurs in the rotation of the two driven gears 14 due to the difference in the number of teeth of the two gears 12b and 12c. The rotation angle detection device 10 can detect (calculate) the rotation angle of the steering shaft as an absolute angle by detecting the phase difference at this time by the magnetic sensor 72 and performing various arithmetic processes by a microprocessor (not shown). .

  FIG. 5 is a front view showing a completed state of the rotation angle detection device 10. On the outer peripheral edge of the holder 30, a protrusion 30 c (rib) is set slightly larger than the outer dimensions of the cover 20 and the case 40. For this reason, in the completed state of the rotation angle detection device 10, the opening ends of the cover 20 and the case 40 are hooked on the protrusion 30 c of the holder 30.

  FIG. 6 is a cross-sectional view (a VI-VI cross section in FIG. 5) showing the internal structure of the rotation angle detection device 10 in a completed state. In the completed state, the gap between the case 40 and the holder 30 is set to a state in which free rotation is allowed with the driven gear 14 supported by the support portions 42 and 38. Further, the case 40 and the holder 30 sandwich and support the driven gear 14 with an appropriate pressing force therebetween, thereby preventing rattling and vibration in the direction of the central axis CL. As shown in FIG. 6, the cam rotor 50 is inserted into the insertion hole 10a of the rotation detecting device from the cover 20 side, and the cam rotor 50 and the main driving gear 12 are snap-coupled.

  In the rotation angle detection device 10 of the above-described embodiment, the main driving gear 12 and each driven gear 14 made of synthetic resin are in contact with a synthetic resin holder (holder member) 30 on one side thereof, and on the other side. Since it rotates while being in contact with the metal case (first cover member) 40, it has a smaller frictional resistance than the structure in which both sides of the main driving gear 12 and each driven gear 14 are rotated in contact with the synthetic resin member. Can rotate. Therefore, since the main driving gear and the driven gear can be directly sandwiched between the holder 30 and the case 40, rattling and vibration of the driven gear 14 can be suppressed. Further, wear due to friction between the main driving gear 12 and the driven gear 14 and the case 40 can be reduced, and the main driving gear 12 and each driven gear 14 can be supported so as to rotate smoothly.

  In the present embodiment, since the case 40 is formed of a stainless steel plate, the influence of the external magnetic field can be cut off, and the change in the magnetic field of the magnet 16 accompanying the rotation of the driven gear 14 can be accurately reproduced. Thereby, the detection accuracy of the rotation angle detection device 10 can be maintained high, and the reliability thereof can be improved.

  Furthermore, since the cover 20 is also formed of a thin stainless steel plate, the influence of the external magnetic field can be more reliably blocked, so that the detection accuracy of the rotation angle detection device 10 can be maintained higher and its reliability can be improved. Can do. In addition, since a large mechanical strength can be maintained even if the plate thickness is thin, a wide space can be secured between the case 40 or the cover 20 and the holder 30, so that the mechanical component element and the electronic component element can be secured. The degree of freedom of design and arrangement can be increased, and various product forms as the rotation angle detection device 10 can be easily realized.

  The present invention can be implemented with various modifications without being limited to the above-described embodiment. In the embodiment, the rotation angle detection device 10 is exemplified as a vehicle steering angle sensor. However, the rotation angle detection device 10 may be used as a steering angle sensor other than the vehicle.

  In the embodiment, the main driving gear 12 is composed of the two-stage gears 12b and 12c, but may be composed of only one-stage gear.

  In the present embodiment, the configuration in which the main driving gear 12 is indirectly connected to the steering shaft has been described. However, the main driving gear 12 may be directly attached to the steering shaft, and the rotation angle detection device 10 may be used. Of course, the configuration in which the cam rotor 50 is not attached may be used.

  In addition, the specific form of each part mentioned by one Embodiment is a preferable illustration to the last, You may change these suitably in implementation of this invention.

It is a perspective view of the rotation angle detection apparatus of one Embodiment. It is the perspective view which decomposed | disassembled and showed the rotation angle detection apparatus to the main components. It is a disassembled perspective view which shows the assembly | attachment relationship of the mechanism component element with respect to a holder. It is a perspective view which expands and shows the meshing state of a main gear and a driven gear. It is a front view which shows the completion state of a rotation angle detection apparatus. FIG. 6 is a cross-sectional view showing the internal structure of the rotation angle detection device 10 in a completed state (cross-section VI-VI in FIG. 5).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rotation angle detection apparatus 12 Main drive gear 14 Driven gear 16 Magnet 20 Cover 30 Holder 30b Opening 38 Support part 40 Case 42 Support part 70 Circuit board 72 Magnetic sensor

Claims (3)

A main gear that rotates by being directly or indirectly connected to a detection object that rotates about a predetermined axis;
A driven gear that meshes with and rotates with the main driving gear;
A magnet provided in the center of the driven gear;
The first object has a first insertion hole formed so that the detection object can be inserted, and the first insertion hole has a support portion that rotatably supports the main driving gear and the driven gear. A holder member having an opening facing the magnet in a state where the driven gear is supported by the support portion;
The detection object has a second insertion hole formed so that the detection object can be inserted, and the main driving gear and the driven gear can be freely rotated between the holder member and the holder member by being assembled from one side thereof. A first cover member to be sandwiched;
A circuit board mounted on the other side of the holder member and mounted with a magnetic detection element facing the magnet through the opening;
A second cover member that has a third insertion hole formed so that the detection object can be inserted, and is attached to the holder member from the other side so as to accommodate the circuit board between the second cover member and the holder member; With
The rotation angle detecting device, wherein the main driving gear, the driven gear, and the holder are made of synthetic resin, and at least the first cover member is formed of a metal plate. The rotation angle detection device according to claim 1,
The rotation angle detecting device, wherein the second cover member is processed from a metal plate. In the rotation angle detection device according to claim 1 or 2,
The rotation angle detection device, wherein the metal plate is made of stainless steel.

Images