JP2024051979A - Steering Angle Sensor - Google Patents

Abstract

To suppress damage or malfunction of a steering angle sensor due to static electricity or magnetic noise.SOLUTION: A steering angle sensor for detecting a steering angle from a shaft that rotates in accordance with steering operation, the steering angle sensor including: a driven gear that performs driven rotation in accordance with rotation of a main gear attached to the shaft; a magnetic sensor for detecting rotation of the driven gear; and a protrusion arranged in proximity to the magnetic sensor and having a protruding end protruding from an outer edge of the magnetic sensor in at least one direction. The protrusion is formed of a material having relative magnetic permeability of 40 or more and conductivity.SELECTED DRAWING: Figure 2

Description

The present invention relates to a steering angle sensor.

For example, a steering angle sensor for detecting the steering angle of a steering wheel is known (see, for example, Patent Document 1 and Patent Document 2). The steering angle sensor is configured with a main gear provided on a shaft that rotates in response to the steering operation of the steering wheel, a driven gear configured to rotate in response to the main gear, and a magnetic sensor that detects the rotation of the driven gear, and can grasp the steering angle based on the rotation angle information detected by the magnetic sensor.

JP 2000-283704 A JP 2000-283705 A

However, in the case of a steering angle sensor, if the magnetic sensor is placed on a path with low electrical resistance, the magnetic sensor may be damaged when static electricity passes through it. Also, in the environment in which the steering angle sensor is used, the density of electronic devices increases, making it easier for magnetic noise to be generated. As a result, the magnetic sensor may malfunction due to magnetic noise, or may be damaged if the magnetic noise is strong.

The present invention aims to provide a technology that suppresses damage or malfunction of steering angle sensors caused by static electricity or magnetic noise.

According to one aspect of the present invention,
A steering angle sensor for detecting a steering angle from a shaft that rotates in accordance with a steering operation,
a driven gear that rotates in accordance with the rotation of a main gear attached to the shaft;
A magnetic sensor for detecting rotation of the driven gear;
a protrusion disposed adjacent to the magnetic sensor and having a protruding end protruding beyond an outer edge of the magnetic sensor in at least one direction;
The protrusion is made of a material having a relative magnetic permeability of 40 or more and having electrical conductivity.
A steering angle sensor is provided.

The present invention makes it possible to prevent damage and malfunction of the steering angle sensor caused by static electricity and magnetic noise.

FIG. 1 is a perspective view showing a schematic configuration of a steering angle sensor according to an embodiment of the present invention. FIG. 2 is a perspective view showing a schematic configuration of the device shown in FIG. 1 with a sensor cover removed. FIG. 3 is a plan view of the schematic configuration of FIG. 2. FIG. FIG. 4 is a partial enlarged view for explaining the structure including the protrusion portion in FIG. FIG. 5 is a front view of the schematic configuration of FIG. 2. FIG. FIG. 6 is a schematic diagram of a side plate, in which (a) is a perspective view and (b) is a side view. FIG. 7 is a diagram showing a modification of the arrangement of the protrusions. FIG. 8 is a diagram showing a modified example of the arrangement of the protrusions.

<One embodiment of the present invention>
Hereinafter, an embodiment of the steering angle sensor according to the present invention will be described with reference to Figs. 1 to 8. Fig. 1 is a perspective view showing a schematic configuration of a steering angle sensor according to an embodiment of the present invention. Fig. 2 is a perspective view showing a schematic configuration in a state in which a sensor cover is removed in Fig. 1. Fig. 3 is a plan view of the schematic configuration in Fig. 2. Fig. 4 is a partially enlarged view of a structure including a protrusion in Fig. 2. Fig. 5 is a front view of the schematic configuration in Fig. 2 when viewed from the front. Fig. 6 is a schematic configuration diagram of a side plate, (a) being a perspective view thereof, and (b) being a side view thereof. Fig. 7 is a diagram showing a modified example of the arrangement of the protrusion. Fig. 8 is a diagram showing a modified example of the arrangement of the protrusion. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof may be simplified or omitted.

The steering angle sensor of this embodiment is attached to a shaft (so-called steering shaft) connected to the steering wheel, and detects the steering angle of the steering wheel from the rotation angle of the shaft that rotates in response to the steering operation of the steering wheel. As shown in Figures 1 and 2, the steering angle sensor 1 is configured with a main gear 2, a circuit board 3, a driven gear 4, a magnetic sensor 5, a sensor cover 6, a side plate 7, and a protrusion 8.

As shown in FIG. 1, the main gear 2 is provided on a shaft 10 that is connected to the steering wheel. The main gear 2 is an annular structure with teeth 2a formed on its outer periphery and an opening on its inside. The main gear 2 is inserted into and fixed to the shaft 10, so that it rotates integrally with the rotation of the shaft 10. The main gear 2 can be formed from a material such as resin.

The circuit board 3 carries the driven gear 4 and the magnetic sensor 5. On one side of the circuit board 3, on which the driven gear 4 and other components are mounted, a circuit (not shown) is provided for sending an electrical signal including rotation angle information from the magnetic sensor 5. The circuit is provided with an insulated wire 9 that is electrically connected to an external device.

The driven gear 4 is provided on one surface (upper surface in FIG. 2) of the circuit board 3. As shown in FIG. 3, the driven gear 4 has teeth 4a formed on its outer periphery and is configured to rotate in response to the rotation of the main gear 2 by engaging with the main gear 2. A magnet (not shown) is housed in the center of the driven gear 4 so that its rotation can be detected by a magnetic sensor 5. The arrangement of the driven gear 4 is not particularly limited as long as it can engage with the main gear 2 and rotate in response to the rotation, but it is preferable that the driven gear 4 is arranged so that a part of the driven gear 4 protrudes from one end of the circuit board 3. In addition, the number of driven gears 4 is not limited to two as shown in FIG. 2 and FIG. 3, and can be changed as appropriate. The material for forming the driven gear 4 can be, for example, a resin.

As shown in FIG. 4, the magnetic sensor 5 is provided on one side of the circuit board 3 and is arranged directly below the center of the driven gear 4 so that the rotation of the driven gear 4 can be detected. The magnetic sensor 5 can convert the change in the magnetic field caused by the rotation of the magnet housed in the driven gear 4 into an electric signal and output it, and outputs an electric signal including rotation angle information according to the rotation angle of the shaft 10. The electric signal output by the magnetic sensor 5 is output to an external device via the circuit board 3 and the insulated electric wire 9. For the magnetic sensor 5, for example, a Hall, GMR (Giant Magneto Resistive), AMR (Anisotropic Magneto Resistive), or other method for detecting a magnetic field can be adopted. Another magnetic sensor 5 (not shown) is arranged directly below the center of the other driven gear 4, which can be seen on the back side of the paper in FIG. 4, and another protrusion 8 (not shown) is arranged below this magnetic sensor 5.

As shown in FIG. 1, the sensor cover 6 covers and protects the circuit board 3, the driven gear 4 and the magnetic sensor 5 mounted thereon. The sensor cover 6 is configured so that the circuit board 3 can be supported and fixed on its inner wall surface, and can house and cover the circuit board 3. The sensor cover 6 is configured so as not to interfere with the engagement between the main gear 2 and the driven gear 4. For example, it has an opening on one side, and is configured so that part of the teeth 4a of the driven gear 4 mounted on the circuit board 3 can be exposed. The sensor cover 6 is formed from, for example, resin.

The side plate 7 is attached to the sensor cover 6 and is used to attach the steering angle sensor 1 to an external member such as a housing. In this embodiment, the side plate 7 has a ring-shaped structure with an opening formed on the inside, as shown in Figs. 6(a) and (b). The sensor cover 6 housing the circuit board 3 is inserted into this opening and fixed, so that the side plate 7 can be attached to the sensor cover 6. The arrangement of the side plate 7 is not particularly limited as long as it can support the steering angle sensor 1, but from the viewpoint of making it easier to arrange the protrusion 8 described below in close proximity to the magnetic sensor 5, it is preferable to arrange the side plate 7 so that it is close to the magnetic sensor 5. The side plate 7 is grounded via an external member such as a housing. The side plate 7 is formed from a steel plate such as SECC (Steel Electrolytic Cold Commercial).

The protrusions 8 suppress the effects of static electricity and magnetic noise on the magnetic sensor 5. The protrusions 8 are disposed close to the magnetic sensor 5 and have a protruding end that protrudes from the outer edge of the magnetic sensor 5 in at least one direction. In this embodiment, the protrusions 8 are provided on the side plate 7 and are disposed so as to protrude from the plane of the side plate 7. In FIG. 4, one protrusion 8 is disposed so as to protrude from each of the two magnetic sensors 5.

According to the protrusion 8, the magnetic noise can be induced to flow to the protrusion 8, and the magnetic noise can be diverted without flowing to the magnetic sensor 5. As a result, the magnetic noise to the magnetic sensor 5 can be reduced. In addition, according to the protrusion 8, by electrically connecting to the side plate 7, the static electricity can be flowed to the side plate 7 through the protrusion 8, and the static electricity flowing to the magnetic sensor 5 can be reduced. From the viewpoint of flowing static electricity and magnetic noise, the protrusion 8 is formed from a material having a relative permeability of 40 or more and having conductivity. From the viewpoint of suppressing the flow of magnetic noise to the magnetic sensor 5 by the protrusion 8, the relative permeability of the material forming the protrusion 8 may be 40 or more, and the upper limit value is not particularly limited, but it is preferable that it is 70,000 or less, for example. As such a material, for example, steel plate (pure iron, silicon steel plate, electromagnetic steel plate, SECC, etc.), nickel, cobalt, etc. can be used. From the viewpoint of cost, the protrusion 8 is preferably made of iron.

Placing the protrusion 8 close to the magnetic sensor 5 means placing the protrusion 8 at a distance from the magnetic sensor 5 that allows magnetic noise entering the vicinity of the magnetic sensor 5 from the outside to be guided to the protrusion 8. By placing them close to each other in this manner, it is possible to suppress the flow of static electricity to the magnetic sensor 5 while diverting the magnetic noise to the protrusion 8 and suppressing the flow to the magnetic sensor 5. The distance to be separated (in FIG. 4, the distance between the bottom surface of the magnetic sensor 5 and the top surface of the protrusion 8) is not particularly limited, but is preferably, for example, 1 mm or more and 3 mm or less.

As shown in FIG. 4, from the viewpoint of more reliably inducing magnetic noise to the protrusion 8, it is preferable that the tip of the protrusion 8 extends in the direction where the magnetic sensor 5 is located, and it is even more preferable that the tip extends beyond the position of the magnetic sensor 5. This makes it possible to more reliably induce magnetic noise that enters the vicinity of the magnetic sensor 5 to the protrusion 8.

The position of the protrusion 8 is not particularly limited as long as it can be arranged to protrude from the outer edge of the magnetic sensor 5. From the viewpoint of arranging the protrusion 8 closer to the magnetic sensor 5, it is preferable to arrange the protrusion 8 so that it extends directly below the magnetic sensor 5 with the circuit board 3 in between, as shown in FIG. 4. Alternatively, it is preferable to arrange it so that it extends to the side of the magnetic sensor 5 placed on the circuit board 3, as shown in FIG. 7. In particular, from the viewpoint of further reducing the magnetic noise passing through the magnetic sensor 5, it is preferable to arrange the protrusion 8 so that it extends directly below the magnetic sensor 5 with the circuit board 3 in between. This is because it is easier to form a closed magnetic circuit for the magnetic field generated by the magnet housed in the driven gear 4.

As shown in Figures 6(a) and (b), it is preferable that the protrusion 8 is formed integrally with the side plate 7. This allows the steering angle sensor 1 to be easily constructed without increasing the number of parts. It also ensures a reliable electrical connection between the protrusion 8 and the side plate 7. To form the protrusion 8 integrally with the side plate 7, for example, a protrusion may be provided on the side plate 7 and the protrusion may be bent.

Note that, although FIG. 4 shows a case where the protrusion 8 is formed integrally with the side plate 7, the present invention is not limited to this, and the protrusion 8 may be formed as a separate body as long as it is electrically connected to the side plate 7.

It is also preferable that the protrusion 8 is positioned so as not to come into contact with the circuit board 3. By arranging it in this manner, it is possible to prevent static electricity from flowing from the protrusion 8 through the circuit board 3 to the magnetic sensor 5. The distance between the protrusion 8 and the circuit board 3 is not particularly limited, and it is sufficient that the protrusion 8 is at a distance that ensures insulation between the protrusion 8 and the circuit board 3. Note that an insulating member such as an insulating sheet may be arranged so as to be in contact with each of the protrusion 8 and the circuit board 3, and the distance between the protrusion 8 and the circuit board 3 may be adjusted by the thickness of this insulating member.

The attachment position of the protrusion 8 on the side plate 7 is not particularly limited and may be changed as appropriate depending on the position of the magnetic sensor 5. From the viewpoint of forming the protrusion 8 short, it is preferable to select a position close to the magnetic sensor 5. In FIG. 4, from the viewpoint of placing the protrusion 8 directly below the magnetic sensor 5 with the circuit board 3 in between, the inner periphery of the side plate 7 having a ring structure is set as the attachment position of the protrusion 8.

The width of the protrusion 8 is not particularly limited as long as it is a width that can induce magnetic noise. In FIG. 4, the width of the protrusion 8 is approximately the same as the width of the magnetic sensor 5, but as shown in FIG. 8, the protrusion 8 may be configured to be wider than the magnetic sensor 5. From the viewpoint of inducing magnetic noise to the protrusion 8 over a wider range, it is preferable to configure the protrusion 8 to be wider than the magnetic sensor 5.

The thickness of the protrusion 8 is preferably set to a thickness that ensures the strength of the protrusion 8, and is preferably set to the same thickness as the side plate 7.

The number of protrusions 8 can be changed appropriately depending on the number of magnetic sensors 5, and is not particularly limited. At least one protrusion 8 needs to be arranged for one magnetic sensor 5, and two or more protrusions 8 may be arranged. For example, when two protrusions 8 are arranged for one magnetic sensor 5, the protrusions 8 may be arranged directly below the magnetic sensor 5 across the circuit board 3 as shown in FIG. 4, and on the side of the magnetic sensor 5 as shown in FIG. 7.

Note that although the shape of the protrusion 8 is rectangular in Figures 6 to 8, there are no particular limitations as long as the structure is capable of inducing and diverting magnetic noise.

<Effects of this embodiment>
According to this embodiment, one or more of the following advantages are achieved.

According to the steering angle sensor 1 of this embodiment, the protrusion 8, which is made of a material having a relative magnetic permeability of 40 or more and is conductive and has a protruding end that protrudes from the outer edge of the magnetic sensor 5 in at least one direction, is arranged close to the magnetic sensor 5. Such a protrusion 8 can induce magnetic noise that enters the vicinity of the magnetic sensor 5 from the outside. In other words, the magnetic noise can be diverted to the protrusion 8 so that it does not enter the magnetic sensor 5. This reduces the magnetic noise that flows into the magnetic sensor 5 and suppresses malfunction of the magnetic sensor 5 due to magnetic noise. In addition, by flowing static electricity through the protrusion 8, the flow of static electricity to the magnetic sensor 5 can be suppressed, and damage to the magnetic sensor 5 due to static electricity can be suppressed.

Furthermore, it is preferable that the protrusion 8 is arranged to protrude from the side plate 7, and that the tip of the protrusion 8 is configured to extend beyond the position of the magnetic sensor 5. This makes it possible to more reliably induce magnetic noise to the protrusion 8 rather than to the magnetic sensor 5, thereby further reducing the magnetic noise passing through the magnetic sensor 5.

It is also preferable that the protrusion 8 is electrically connected to the side plate 7. This allows static electricity to flow through the protrusion 8 to the side plate 7 and then to the housing (not shown) to which the side plate 7 is attached, making it possible to more reliably prevent damage to the magnetic sensor 5 caused by static electricity.

It is also preferable that the protrusion 8 is formed integrally with the side plate 7. This allows the steering angle sensor 1 to be constructed easily without increasing the number of parts. It also ensures a reliable electrical connection between the protrusion 8 and the side plate 7.

The protrusion 8 is preferably arranged so as to extend directly below the magnetic sensor 5 across the circuit board 3. Alternatively, it is preferably arranged so as to extend to the side of the magnetic sensor 5 placed on the circuit board 3. With this arrangement, magnetic noise can be more reliably induced to the protrusion 8, thereby further reducing the magnetic noise to the magnetic sensor 5, and the flow of static electricity to the magnetic sensor 5 can be more reliably suppressed. Furthermore, these arrangements (directly below and on the side of the magnetic sensor 5) may be used in combination.

It is also preferable that the protrusion 8 is provided on the side plate 7 so as not to come into contact with the circuit board 3. This makes it possible to more reliably suppress the flow of static electricity from the protrusion 8 to the circuit board 3 and the magnetic sensor 5.

It is also preferable that the protrusion 8 is configured to be wider than the magnetic sensor 5. This allows magnetic noise to be induced to the protrusion 8 over a wider range, and the flow of magnetic noise to the magnetic sensor 5 can be more reliably suppressed.

Although one embodiment of the present invention has been specifically described above, the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the invention.

<Preferred embodiment of the present invention>
Preferred embodiments of the present invention will be described below.

(Appendix 1)
One aspect of the present invention is
A steering angle sensor for detecting a steering angle from a shaft that rotates in accordance with a steering operation,
a driven gear that rotates in accordance with the rotation of a main gear attached to the shaft;
A magnetic sensor for detecting rotation of the driven gear;
a protrusion disposed adjacent to the magnetic sensor and having a protruding end protruding beyond an outer edge of the magnetic sensor in at least one direction;
The protrusion is made of a material having a relative magnetic permeability of 40 or more and having electrical conductivity.
This is a steering angle sensor.

(Appendix 2)
In Supplementary Note 1, preferably,
a circuit board supporting the driven gear and the magnetic sensor;
a sensor cover for protecting the circuit board;
a side plate attached to the sensor cover for attaching the steering angle sensor to an external member;
The protrusion is provided on the side plate and is disposed so as to protrude from the side plate.

(Appendix 3)
In Supplementary Note 2, preferably,
The protrusion is integrally formed with the side plate.

(Appendix 4)
In addition 2 or 3, preferably,
The protrusion is disposed so as to extend directly below the magnetic sensor with the circuit board therebetween.

(Appendix 5)
In addition 2 or 3, preferably,
The protrusion is disposed so as to extend along a side surface of the magnetic sensor mounted on the circuit board.

(Appendix 6)
In any of Supplementary Notes 1 to 5, preferably,
The protrusion is configured so that its tip extends beyond the position of the magnetic sensor.

(Appendix 7)
In any of Supplementary Notes 1 to 6, preferably,
The protrusion is configured to be wider than the magnetic sensor.

REFERENCE SIGNS LIST 1 Steering angle sensor 2 Main gear 2a Teeth of main gear 3 Circuit board 4 Driven gear 4a Teeth of driven gear 5 Magnetic sensor 6 Sensor cover 7 Side plate 8 Projection 9 Insulated electric wire 10 Shaft

Claims (6)

A steering angle sensor for detecting a steering angle from a shaft that rotates in accordance with a steering operation,
a driven gear that rotates in accordance with the rotation of a main gear attached to the shaft;
A magnetic sensor for detecting rotation of the driven gear;
a protrusion disposed adjacent to the magnetic sensor and having a protruding end protruding beyond an outer edge of the magnetic sensor in at least one direction;
The protrusion is made of a material having a relative magnetic permeability of 40 or more and having electrical conductivity.
Steering angle sensor. a circuit board supporting the driven gear and the magnetic sensor;
a sensor cover for protecting the circuit board;
a side plate attached to the sensor cover for attaching the steering angle sensor to an external member;
The protrusion is provided on the side plate and disposed so as to protrude from the side plate.
2. The steering angle sensor according to claim 1. The protrusion is integrally formed with the side plate.
The steering angle sensor according to claim 2. The protrusion is configured so that its tip extends beyond the position of the magnetic sensor.
The steering angle sensor according to any one of claims 1 to 3. The protrusion is wider than the magnetic sensor.
The steering angle sensor according to any one of claims 1 to 3. The protrusion is wider than the magnetic sensor.
5. The steering angle sensor according to claim 4.

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