JP2008298673A - Rotation angle detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously reduce faults when using resin as both materials and faults when using metal as one material, regarding a shaft member 3 and a bearing member (a housing 13) which bears bearing function in a rotation angle detector 1. <P>SOLUTION: The rotation angle detector 1 constitutes the bearing function by supporting the resin shaft member 3, excelling in bearing performance with a friction coefficient based on a Suzuki-type wear test being 0.20 or less, directly to the resin housing 13. Since both the shaft member 3 and the housing 13 that serve as the bearing member are provided using resin as material, nonconformities for the case of using metal as material can be eliminated. The shaft member 3 is provided in substantially a cylindrical shape, and by having a yoke 5 that uses metal as material stuck to a surface portion of an inner peripheral surface 4, including a center portion 17, the nonconformities for the case of using resin as the material can be reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotation angle detection device that detects the rotation angle of an accelerator pedal.

  2. Description of the Related Art Conventionally, an accelerator opening used for engine operation control or the like is detected as a rotation angle of an accelerator pedal (hereinafter referred to as a pedal) that rotates by a pedaling force and is output to an electronic control unit (ECU). The rotation angle detecting device for detecting the rotation angle of the pedal includes a permanent magnet that rotates together with the pedal, and an output generating means such as a Hall IC that detects a magnetic change accompanying the rotation of the permanent magnet and converts it into an electric signal. The electric signal is input to the ECU and used for engine operation control and the like.

  By the way, this rotation angle detection device is provided so as to include an element having a bearing function for bearing the rotation of the pedal together with an element having a detection function for detecting the rotation angle of the pedal, such as a permanent magnet and an output generating means. Yes.

  For example, according to the rotation angle detection device described in Patent Document 1, a metal rod-shaped bearing member (described as a rod 56 in Patent Document 1) in a resin-made housing that houses a permanent magnet and output generating means. Is fixed, and the resin pedal is supported by the bearing member via the bush. In the following description, a member supported by the bearing member is a shaft member (that is, the shaft member is a rotating member, and in Patent Document 1, the pedal itself corresponds to the shaft member).

  However, when one of the bearing member or the shaft member is provided using a metal as a material, it is necessary to use an expensive material from the rust-proof surface. That is, even if an inexpensive metal material such as iron is used as the base material and the anti-rust plating treatment is applied to the surface of the base material, the plating is peeled off due to repeated sliding of the bearing, and the base material rusts and the bearing performance decreases. There is a risk of it. Further, when one of the bearing member or the shaft member is provided using a metal as a raw material, another member (for example, a bush in Patent Document 1) is interposed between the bearing member and the shaft member in order to maintain the bearing performance for a long time. There is a need. Furthermore, the use of metal as a raw material itself is a problem that should be corrected in view of the recent promotion of weight reduction of vehicles.

On the other hand, as in the rotation angle detection device described in Patent Document 2, the bearing member is provided as a rod-shaped resin integral with the housing, and the resin pedal is directly supported by the bearing member. is there. However, when both the bearing member and the shaft member are made of resin as a raw material, the bearing member is easily deformed by a load of a treading force or other urging force, and is unstable in strength.
US Patent Application Publication No. 2002/0175676 German Patent Application Publication No. 19503335

  The present invention has been made to solve the above-described problems, and an object of the present invention is related to a bearing member and a shaft member having a bearing function of pedal rotation in a rotation angle detection device, and both the bearing member and the shaft member are provided. It is to simultaneously reduce the problem when the material is made of resin and the problem when one material of the bearing member or the shaft member is metal.

[Means of Claim 1]
The rotation angle detection device according to claim 1 detects a rotation angle of an accelerator pedal that rotates by a pedaling force, is provided in a substantially cylindrical shape and is made of a resin shaft member that rotates together with the accelerator pedal, and a substantially cylindrical shape. A yoke that is provided and is fixed to the inner peripheral surface of the shaft member and rotates coaxially with the shaft member, a permanent magnet that is fixed to the inner peripheral surface of the yoke and rotates together with the shaft member and the yoke, and a magnetic change accompanying the rotation of the permanent magnet Output generating means for generating an output in accordance with. The shaft member has a friction coefficient of 0.20 or less according to the Suzuki wear test, and the yoke is fixed to at least a half of the axial length of the shaft member within the inner peripheral surface of the shaft member. is doing.

  Accordingly, the rotation angle detection device configures a bearing function by causing a resin-made shaft member having excellent bearing performance to be directly supported by a resin-made housing or the like. That is, since both the shaft member and the housing as the bearing member can be provided with resin as a material, there is a problem in using one of the bearing member or the shaft member with metal as a material (use of a high-priced material having an antirust effect). Further, the insertion of another member between the bearing member and the shaft member and the increase in weight due to the use of a metal material can be eliminated.

  In addition, the shaft member is provided in a substantially cylindrical shape, and a yoke made of a metal, which is one of the elements responsible for the detection function, is fixed to the inner peripheral surface of the shaft member so that both the bearing member and the shaft member are made of resin. Inconvenience (such as instability of strength) can be reduced. Further, since the shaft member is supported by the bearing member at both ends in the axial direction, the yoke is fixed to at least a half of the axial length of the shaft member within the inner peripheral surface of the shaft member. The strength of unstable parts that are not bearings can be reliably increased.

As described above, in the rotation angle detection device, regarding the bearing member and the shaft member that bear the bearing function of the pedal rotation, simultaneously reducing the problem when both materials are made of resin and the problem when one material is metal. Can do.
In addition, since the yoke is fixed to the inner peripheral surface of the shaft member and does not slide in contact with other members, an inexpensive magnetic metal such as iron is used as a base material, and the base material surface is subjected to a rust-proof plating treatment. A yoke can be provided at low cost.

[Means of claim 2]
According to the rotation angle detecting device of the second aspect, the permanent magnet has a portion of the inner circumferential surface of the shaft member that is ½ of the axial length of the shaft member from the inner circumferential side via the yoke. Covering.
Thereby, the terminal of an output generation means can be pulled out from both the axial direction both ends of a shaft member. For this reason, a freedom degree can be raised regarding arrangement | positioning of the connector for connecting an output generation means and ECU.

The rotation angle detection device of the best mode 1 detects the rotation angle of an accelerator pedal that rotates by a pedaling force, and is provided in a substantially cylindrical shape and a resin shaft member that rotates together with the accelerator pedal. A yoke that is fixed to the inner peripheral surface of the shaft member and rotates coaxially with the shaft member, a permanent magnet that is fixed to the inner peripheral surface of the yoke and rotates together with the shaft member and the yoke, and a magnetic change caused by the rotation of the permanent magnet. Output generating means for generating a corresponding output. The shaft member has a friction coefficient of 0.20 or less according to the Suzuki wear test, and the yoke is fixed to at least a half of the axial length of the shaft member within the inner peripheral surface of the shaft member. is doing.
According to the rotation angle detecting device of the best mode 2, the permanent magnet covers a half of the axial length of the shaft member in the inner peripheral surface of the shaft member from the inner peripheral side via the yoke. ing.

[Configuration of Example 1]
A configuration of the rotation angle detection device 1 according to the first embodiment will be described with reference to FIGS. 1 and 2.
The rotation angle detection device 1 detects a rotation angle of an accelerator pedal (hereinafter abbreviated as a pedal) 2 that rotates by a pedaling force, and the detected rotation angle is an electronic control unit (ECU: not shown) as an accelerator opening. ) And used for operation control of an engine (not shown).

  As shown in FIGS. 1 and 2, the rotation angle detection device 1 includes a shaft member 3 provided in a substantially cylindrical shape and rotated together with a pedal 2 and supported by a bearing member, and a shaft member 3 provided in a substantially cylindrical shape. A yoke 5 fixed to the inner peripheral surface 4 and rotated together with the shaft member 3, a permanent magnet 6 fixed to the inner peripheral surface of the yoke 5 and rotated together with the shaft member 3 and the yoke 5, and a magnetic change accompanying the rotation of the permanent magnet 6. Output generating means 7 for generating a corresponding output.

  That is, the rotation angle detection device 1 has a bearing function for bearing the rotation of the pedal 2 like the shaft member 3 together with the elements responsible for the detection function of detecting the rotation angle of the pedal 2 such as the permanent magnet 6 and the output generation means 7. It is provided with the element which bears.

Here, the pedal 2 includes an arm 10 that receives a pedaling force and a rotor 11 that engages with the arm 10 and rotates integrally with the arm 10. The rotor 11 is rotated by a spring 12 in a direction opposite to the pedaling force. Be forced. That is, the spring 12 functions as a restoring spring for the pedaling force.
The engaging portion between the arm 10 and the rotor 11 is accommodated in a resin housing 13.

  The shaft member 3 is fixed to the arm 10 so as to rotate integrally with the arm 10, and a fixing portion between the shaft member 3 and the arm 10 is accommodated in the housing 13. The shaft member 3 is supported by the housing 13 by the outer peripheral surfaces at both ends in the axial direction being in direct sliding contact with the sliding contact surface 14 provided on the housing 13. That is, the housing 13 serves as a bearing member, and the rotation of the pedal 2 is supported by the housing 13 via the shaft member 3, and the rotation axis of the pedal 2 coincides with the axis of the shaft member 3.

  Further, the shaft member 3 is provided with a resin as a raw material. In order to improve the bearing performance, the shaft member 3 has a friction coefficient of 0.20 or less, more preferably 0.15, according to the Suzuki-type wear test. The following is adopted. Examples of resin materials having good bearing performance include, for example, polyolefins containing oil such as polypropylene containing oil, and Teflon (such as nylon 6 containing Teflon (registered trademark)). (Registered Trademark) may be mentioned in which polyamide is contained.

  The yoke 5 is provided by using an inexpensive magnetic metal such as iron as a base material and subjecting the surface of the base material to rust-proof plating. That is, since the yoke 5 is fixed to the inner peripheral surface 4 and does not slidably contact other members, it can be provided at such a low cost. The yoke 5 is fixed to the inner peripheral surface 4 coaxially with the shaft member 3. Here, the surface portion of the inner peripheral surface 4 fixed to the yoke 5 is a portion that is ½ of the axial length of the shaft member 3 (shown as a portion that intersects the center line in the figure: hereinafter, the center portion) 17). The yoke 5 is fixed to a surface portion including the center portion 17 and deviating to the left side in the figure.

  The permanent magnet 6 is composed of two magnets. The two permanent magnets 6 are opposed and fixed to the inner peripheral surface of the yoke 5 so as to generate a magnetic flux in a direction perpendicular to the axis of the shaft member 3. The Since the yoke 5 is biased to the left side in the figure and is fixed to the inner peripheral surface 4, the permanent magnet 6 is also unevenly distributed on the left side in the figure on the inner peripheral side of the shaft member 3.

  The output generation means 7 is, for example, a known Hall element 19 that senses a magnetic change accompanying rotation of the permanent magnet 6 and a processing circuit (not shown) that converts the magnetic change sensed by the Hall element 19 into an electrical signal. The obtained Hall signal is output to the ECU. Then, the ECU grasps the actual value of the accelerator opening based on the electric signal, and executes engine operation control or the like according to the grasped actual value of the accelerator opening.

  Here, the Hall element 19 is on the axial center of the shaft member 3 and in the axial direction of the permanent magnet 6 so that the magnetic flux density intersecting with the Hall element 19 regularly changes according to the rotation angle of the pedal 2 or the shaft member 3. It is arranged at half the position. For this reason, the Hall element 19 is unevenly distributed on the left side in the figure on the inner peripheral side of the shaft member 3, and the terminal 20 of the Hall element 19 is pulled out from the left end of the shaft member 3 and connected to the circuit board 21 on which the processing circuit is mounted. The

  The circuit board 21 is resin-molded together with connector terminals 22 for outputting electrical signals to the ECU to form an integral sensor cover 23, and the connector 24 is provided as a part of the sensor cover 23. The sensor cover 23 is attached to the left side of the housing 13 (that is, the side from which the terminal 20 of the Hall element 19 is pulled out).

[Effect of Example 1]
A rotation angle detection device 1 according to the first embodiment is provided in a substantially cylindrical shape and rotates with a pedal 2 made of resin, and is fixed to an inner peripheral surface 4 of the shaft member 3 and rotates coaxially with the shaft member 3. A yoke 5, a permanent magnet 6 fixed to the inner peripheral surface of the yoke 5 and rotating together with the shaft member 3 and the yoke 5, and an output generating means 7 for generating an electric signal corresponding to a magnetic change accompanying the rotation of the permanent magnet 6. The shaft member 3 has a friction coefficient of 0.20 or less according to the Suzuki-type wear test, and the surface portion of the inner peripheral surface 4 fixed to the yoke 5 includes a center portion 17.

  Thereby, the rotation angle detection apparatus 1 comprises a bearing function by directly bearing the resin shaft member 3 having excellent bearing performance on the resin housing 13. That is, since both the shaft member 3 and the housing 13 as a bearing member are provided with a resin as a material, there is a problem (use of a high-priced material having a rust-preventing effect, The insertion of another member between the bearing member and the shaft member 3 and the increase in weight due to the use of a metal material can be eliminated.

  In addition, the shaft member 3 is provided in a substantially cylindrical shape, and a yoke 5 made of a metal material is fixed to the inner peripheral surface 4 thereof, so that a problem (provided in terms of strength) is caused when an element responsible for the bearing function is made of resin. Stability, etc.) can be reduced. Further, since the shaft member 3 is supported by the housing 13 at both ends in the axial direction, by fixing the yoke 5 to the surface portion including the center portion 17 of the inner peripheral surface 4, the strength of the unstable portion that is not supported is increased. Can be raised reliably.

  As described above, in the rotation angle detection device 1, it is possible to simultaneously reduce a problem when providing an element that bears a bearing function using a metal as a material and a problem when providing an element that bears a bearing function using a resin as a material.

According to the rotation angle detection device 1 of the second embodiment, the inner circumference of the yoke 5 is such that the permanent magnet 6 covers the center portion 17 from the inner circumference side via the yoke 5 as shown in FIG. Fixed to the surface.
Thereby, the terminal 20 of the Hall element 19 can be pulled out from both the left and right ends of the shaft member 3 in the drawing. Therefore, the sensor cover 23 may be attached to the left side of the housing 13 as shown in FIG. 3 or may be attached to the right side as shown in FIG.

[Modification]
According to the rotation angle detection device 1 of the first embodiment, the yoke 5 is fixed to the left-side surface portion including the center portion 17 (see FIG. 2), but as shown in FIG. The yoke 5 may be fixed to the entire surface. That is, the surface portion to which the yoke 5 is fixed may be arbitrarily set within a range including the center portion 17.

It is sectional drawing which shows the structure of a rotation angle detection apparatus (Example 1). (A) is a longitudinal cross-sectional view which shows the principal part of a rotation angle detection apparatus, (b) is a cross-sectional view which shows the principal part of a rotation angle detection apparatus (Example 1). (A) is a cross-sectional view showing a main part of the rotation angle detection device when the terminal of the Hall element is pulled out from the left side, and (b) is a plane showing the rotation angle detection device when the sensor cover is attached to the left side of the housing. (Example 2) which is a figure. (A) is a cross-sectional view showing a main part of the rotation angle detection device when the terminal of the Hall element is pulled out from the right side, and (b) is a plane showing the rotation angle detection device when the sensor cover is attached to the right side of the housing. (Example 2) which is a figure. It is a cross-sectional view which shows the principal part of a rotation angle detection apparatus (modification example).

Explanation of symbols

1 Rotation angle detector 2 Pedal (accelerator pedal)
3 Shaft member 4 Inner peripheral surface (inner peripheral surface of the shaft member)
5 Yoke 6 Permanent magnet 7 Output generating means 17 Center portion (a portion of the inner circumferential surface of the shaft member that is ½ of the axial length of the shaft member)

Claims (2)

In a rotation angle detection device that detects the rotation angle of an accelerator pedal that rotates by a pedaling force,
A resin shaft member provided in a substantially cylindrical shape and rotating together with the accelerator pedal;
A yoke that is provided in a substantially cylindrical shape and is fixed to the inner peripheral surface of the shaft member, and rotates coaxially with the shaft member;
A permanent magnet fixed to the inner peripheral surface of the yoke and rotating together with the shaft member and the yoke;
Output generating means for generating an output corresponding to the magnetic change accompanying the rotation of the permanent magnet,
The shaft member has a friction coefficient of 0.20 or less by a Suzuki-type wear test,
The rotation angle detecting device according to claim 1, wherein the yoke is fixed to at least a half of the axial length of the shaft member in the inner peripheral surface of the shaft member. The rotation angle detection device according to claim 1,
The permanent magnet covers a portion of the inner circumferential surface of the shaft member that is ½ of the axial length of the shaft member from the inner circumferential side through the yoke. Detection device.

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