JP4964168B2 - Rotation detection sensor - Google Patents

Description

  The present invention relates to a rotation detection sensor such as an automobile wheel speed sensor or an engine speed sensor.

  For example, as shown in FIG. 6, a wheel speed sensor P, which is one of the rotation detection sensors, links a detection unit a composed of a magnetoelectric conversion element 1 such as a Hall element or a magnetoresistive element (MR element) to the wheel. The rotating body (detected body) B is made to face, and the detection unit a detects a magnetic field variable due to the rotation of the rotating body B, converts it into an electrical signal, and outputs it to the cable 6.

The wheel speed sensor P is provided in a disc brake, a hub, a brake drum, or the like, which is an underbody part of the vehicle body. It is general that the screw (bolt) E is fixed to the member A and attached (refer to FIG. 1 in Patent Document 1 and FIG. 1 in Patent Document 2).
JP 2003-307522 A JP 2007-170963 A

  As one of the wheel speed sensors P, the detecting portion a is positioned on the resin holder 3 as a pair of long plate-like lead terminals 2 and 2 led out in parallel from the plate-like magnetoelectric transducer 1. There is a configuration in which the detection part a, the holder 3 and a part of the cable 6 are embedded and a resin coating 4 is embedded (see FIG. 1 of Patent Document 1, FIG. 1 of Patent Document 2, etc.).

Further, the wheel speed sensor P is generally cylindrical and has a shape that protrudes in the lateral direction from the fixed flange 5 from the above mounting mode, and the general plate-like magnetoelectric transducer 1 has a thickness direction ( The vertical direction in FIG. 6 is the detection direction, and is classified into an end face detection type and a side face detection type according to the attachment mode with respect to the holder 3.
In the end face detection type, the thickness direction of the magnetoelectric conversion element 1 faces the longitudinal direction of the rotation detection sensor P (see FIG. 9 of Patent Document 1), and in the side detection type, the thickness direction of the magnetoelectric conversion element 1 rotates. It faces the radial direction of the detection sensor (direction perpendicular to the longitudinal direction) (see FIG. 1 of Patent Document 2). Many wheel speed sensors P can be classified into these two types. However, depending on the type of the magnetoelectric conversion element 1, the plate thickness direction may not coincide with the detection direction.

  By the way, this type of wheel speed sensor P is incorporated in an ABS (anti-lock brake system) or the like in the vehicle and installed around the vehicle wheel as described above. Various parts are also installed around the wheel as the vehicle becomes more sophisticated. Each part is required to be downsized due to the mounting space and the like, and the wheel speed sensor P is no exception. That is, the wheel speed sensor P is desired to be light and thin today.

  Further, as described above, the wheel speed sensor P is generally attached to the attachment member A such as a disc brake via the hole D. At this time, if the mounting hole D is large, the strength of the mounting member A is reduced and a necessary mounting space is increased. Therefore, the mounting hole D is preferably as small as possible. In order to make the mounting hole D small, it is necessary to make the body of the wheel speed sensor P fitted into the hole D thinner (smaller in diameter).

  The present invention has a first object of downsizing the wheel speed sensor P, in particular, reducing the portion that fits into the mounting hole D in response to such a request for lightness, thinness, and resin coating 4 accompanying the downsizing. The second problem is to increase the supporting and fixing force of the magnetoelectric conversion element 1 to the holder 3 by the above.

In order to achieve the first object, the present invention sets the width t of the holder to be equal to or less than the width T of the plate-like magnetoelectric transducer (T ≧ t in FIG. 3).
Conventionally, as shown in FIGS. 3 and 4 of Patent Literature 1 and Patent Literature 2 and FIGS. 3 and 4, the magnetoelectric conversion element is fitted into the mounting recess of the holder, and fitted walls (reference numeral 3a in FIG. 6) at both ends in the width direction. Therefore, the width of the detection part a is determined by the width of the holder, and the resin is coated to the required thickness from the width of the holder.
However, if the width of the holder is less than or equal to the width of the plate-like magnetoelectric transducer, the reference for the thickness of the resin coating is the width of the magnetoelectric transducer, and the resin coating (rotation detection sensor) has the same thickness as the fitting wall. The trunk becomes thinner (the diameter becomes smaller).

  As a configuration of the invention according to this means, a pair of long plate-like lead terminals are derived in parallel from a plate-like magnetoelectric transducer that detects a magnetic field variable due to rotation of the detected object, converts it to an electrical signal, and outputs it. A detection unit, a bar-shaped holder to which the detection unit is attached, a cable connected to the lead terminal and drawn out in the lead-out direction of the lead terminal to transmit the electrical signal to the outside, and the detection unit and the cable In the rotation detection sensor comprising a resin coating covering a part, the magnetoelectric transducer is placed and fixed on the mounting plane of the holder with its plate surface, and the parallel direction of the pair of lead terminals is set. It is possible to adopt a configuration in which the direction along the plate surface of the magnetoelectric transducer is set, and the width of the holder in the direction along the plate surface is equal to or less than the width of the magnetoelectric transducer along the plate surface.

If the conventional fitting wall 3a is eliminated and the magnetoelectric transducer is only placed on the mounting plane of the holder with its plate surface, the magnetoelectric transducer needs to be positioned and fixed to the holder by some means. . As the means, known means such as adhesion may be appropriately employed. For example, a holder protrusion is fitted between parallel pairs of lead terminals derived from the magnetoelectric transducer, or the relationship between the lead terminals is determined. It is possible to fix the positioning by fitting the projection of the holder into the hole.
Since the positioning and fixing by this fitting only needs to be maintained until the resin coating is solidified, the fitting means is sufficient. In addition, the means for fitting the holder protrusion between the pair of lead terminals or fitting the holder protrusion into the engagement hole of the lead terminal has no effect on the width of the holder (using existing space Since it is not necessary to increase the width of the holder by forming the fitting means, it is advantageous for downsizing the holder.

The means for fitting the protrusion of the holder into the engagement hole of the lead terminal between the pair of lead terminals may be only the same means, or these means may be used in combination. At this time, as long as the positioning and fixing of the magnetoelectric transducer to the holder is maintained until the resin coating is solidified, the mode is arbitrary. However, the magnetoelectric transducer is fitted in at least two places, for example.
Incidentally, if the lead terminal is in the form of a long plate, it has sufficient rigidity to be able to position and fix the magnetoelectric transducer to the holder.

In order to achieve the second problem, the present invention reduces the cross-sectional shape of the holder.
Normally, the holder is in the shape of a rod, and as described above, even if the reference of the thickness of the resin coating is the width of the magnetoelectric transducer (end side surface in the width direction), it is determined by the resin coating (resin coating). Since the size of the fuselage (determined by the outer shape of the holder) is fixed, if the cross-sectional shape of the holder is large (the cross-sectional area is large), the thickness of the resin coating around the holder and the magnetoelectric transducer is inevitably thin. Become. If it becomes thin, the support fixing force of the magnetoelectric transducer to the holder by the resin coating surrounding the periphery will decrease.
For this reason, if the cross-sectional shape of the holder is reduced, the thickness of the resin coating surrounding it increases, and the support fixing force of the magnetoelectric transducer to the holder by the resin coating is improved (increased).
At this time, the cross section of the holder is symmetrical with respect to the center axis of the width of the magnetoelectric transducer, and the width of the holder in the direction along the plate surface of the magnetoelectric transducer is changed from the magnetoelectric transducer to the plate thickness. If it is made to become narrow gradually as it leaves | separates in a direction, the thickness of a resin coating can be made into the same thickness on either side with respect to a magnetoelectric transducer (a uniform thickness can be achieved).

  As a configuration of the invention according to this means, in the configuration of the invention that achieves the first object, the plate surface of the magnetoelectric transducer is set to the cable drawing direction, and the holder has the rod-shaped cross section of the magnetoelectric conversion. The element has a symmetrical shape with respect to the center axis of the width, and the width (width in the direction along the magnetoelectric transducer plate surface) is gradually narrowed from the magnetoelectric transducer in the plate thickness direction. Can be adopted.

  According to the invention for achieving the first problem, since the body of the resin coating, that is, the rotation detection sensor can be made thin, the mounting hole of the rotation detection sensor can be made small, and the strength of the vehicle frame or the like is not reduced. The mounting space can also be reduced. In addition, if the body is thinned, the rotation detection sensor can be lightened. That is, the rotation detection sensor can be reduced in size, thickness, and size.

  In addition, according to the invention for achieving the second problem, since the thickness of the resin coating can be made uniform, warpage and shape defects due to uneven shrinkage of the resin coating after molding, cracks in the thinnest wall portion are generated. Can be suppressed as much as possible.

  1 to 4 show a wheel speed sensor P according to this embodiment, in which the detection unit a has a straight line parallel to a Hall IC 11 having a Hall element (rotation detection element) for detecting a magnetic field variation. Further, a long plate piece lead piece (lead terminal) 12 is derived. The detection portion a is attached to the holder 20 and the lead wires 12 and 12 are connected to the flexible wires (conductors) of the pair of insulated wires 6a and 6a of the output cable 6 by soldering or the like (FIGS. 1 and 2). reference).

In the state where the cable 6 is connected to the Hall IC 11 attached to the holder 20, the wheel speed sensor P is formed by injection molding the Hall IC 11, the lead piece 12, the entire holder 20, and the resin coating 4 in which a part of the output cable 6 is embedded. Get. At the time of this resin molding, the fixed flange 15 in which the metal ring 16 is embedded is integrally molded. With this fixed flange 15, the wheel speed sensor P is attached to the vehicle body frame in the same manner as in the prior art (see FIG. 6).
The fixing flange 15 may not be integral with the resin coating 4 but may be a separate one made of metal or the like. At that time, the separate fixing flange 15 is inserted when the resin coating 4 is molded and integrated with the resin coating 4 (see FIG. 1 of Patent Document 2).

The Hall IC 11 has a square plate-like shape, and is obtained by protecting the IC chip 11a having the sensor element 11b with a thermosetting resin such as an epoxy resin (protective resin portion 11c).
As shown in FIG. 4, the resin molded product holder 20 is in the form of a bar having a rectangular parallelepiped shape, and a mounting plane 21 for the Hall IC 11 is formed at the front of the upper surface thereof. Engagement projections 22 and 23 are formed on the upper surface of the holder 20 behind the mounting plane 21. One of the engagement projections 22 is fitted into the engagement hole 13 of the pair of lead pieces 12 and the other engagement is performed. The Hall IC 11 is positioned and fixed to the holder 20 by fitting the projection 23 between the lead pieces 12 and 12.

  The positions and number of the engaging protrusions 22 and 23 are arbitrary as long as the Hall IC 11 can be positioned and fixed to the holder 20. Further, in order to ensure the positioning and fixing, a locking mechanism such as a claw is provided on the engaging protrusions 22 and 23 (see Patent Document 1, Claim 2, Paragraph 0016), or the distal end portions of the engaging protrusions 22 and 23 Can be caulked with heat.

  The width of the Hall IC 11 in the direction along the plate surface 11d (the width in the parallel direction of the pair of lead terminals 12 and 12) t is equal to or less than the width T of the Hall IC 11 in the direction along the plate surface 11d (T ≧ t). (See FIG. 3). The width t is appropriately set as long as the Hall IC 11 is supported and fixed to the holder 20. With this width T ≧ t, the required thickness reference of the resin coating 4 is the side surface of the Hall IC 11 (the side surfaces on both ends in the width T direction), and the resin coating 4 has a constant thickness (a certain thickness is ensured). Therefore, the body of the resin coating 4 (wheel speed sensor P) around the Hall IC 11 is thinner (the diameter is smaller) than the case where the side of the holder 20 with the width: T <t is the reference. ).

  As shown in FIG. 5, the holder 20 has a bar-like longitudinal section symmetrical with respect to an axis in the plate thickness direction of the Hall IC 11 (a central axis of the width in the horizontal direction of the Hall IC 11 in FIG. 3) 1. If the width t in the direction along the plate surface 11d of the Hall IC 11 is gradually narrowed away from the Hall IC 11 in the plate thickness direction (vertical direction in FIG. 3), the thickness of the resin coating 4 surrounding the circumference thereof As the thickness increases, the supporting and fixing force of the Hall IC 11 to the holder 20 by the resin coating 4 is increased.

The degree of narrowing the width t is appropriately determined in consideration of the strength of the holder 20 and the like. Further, the shape of the side surface 20a with the narrow width t is also arbitrary, such as a straight line shape as shown in FIG. 10A or an arc shape as shown in FIG. In addition, the mounting plane 21 of the Hall IC is preferably on the center line c in the vertical direction of the circular cross section of the wheel speed sensor P formed by the resin coating 4, but it is not possible to design (layout) (offset) (If not), move as close as possible.
Incidentally, in the case of the offset, the outer shape of the resin coating 4 must be a circular shape in which the required thickness is secured from each surface of the Hall IC 11, compared with the case where it is on the center line c. The thickness of the resin coating 4 at the center line c is increased (the outer diameter of the body is increased), but the sensor P for which the thickness reference of the resin coating 4 is determined by the width t of the conventional holder 3 is used. Compared to that, its body is thinner.

In each of the above embodiments, the long plate piece-like lead piece 12 is led out from the Hall IC 11 in a straight line in parallel (side detection type), but the lead piece 12 is bent into an L shape (Patent Document) (Refer to FIG. 1, FIG. 9, Patent Document 2, FIG. 9 and the like) Of course, the present invention can also be applied to the end face detection type attached to the holder 20. In the case of this L-shaped lead piece 12, the cable 6 is drawn in the lead-out direction of the lead piece 12 after bending (the longitudinal direction of the sensor P).
Further, an electronic component such as a capacitor may be fixed between the lead pieces 12 (see reference 13 in FIG. 3 in Patent Document 2). In this case, since the pair of lead pieces 12 and 12 are integrated by the two parts of the electronic component and the protective resin portion 11c of the Hall IC, the shape of the protrusions 22 and 23, for example, the cross section is rectangular or elliptical. In other words, the Hall IC 11 can be positioned and fixed to the holder 20 with a sufficient maintenance force by fitting the one protrusions 22 and 23 together.
Furthermore, although the wheel speed sensor P is used, it is needless to say that the present invention can be adopted in other rotation detection sensors.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Cutting plan view of one embodiment Cut front view of the same embodiment Cut left side view of the same embodiment Perspective view of Hall IC and holder of the same embodiment Cutaway view of main parts of other embodiments Wheel speed sensor mounting schematic diagram

4 Resin coating 6 Output cable 6a Cable insulation core 11 Hall IC (magnetoelectric transducer)
11d Hall IC plate surface 12 Lead piece (plate-like lead terminal)
13 Engagement hole 20 Holder 21 Magnetoelectric transducer mounting planes 22 and 23 Engagement protrusion B Rotating body (detected body)
P Wheel speed sensor (rotation detection sensor)
a Detector

Claims (2)

A pair of long plate-like lead terminals (12, 12) are derived in parallel from a plate-like magnetoelectric transducer (11) that detects a magnetic field variable due to rotation of the detected body (B), converts it into an electrical signal, and outputs it. The detection unit (a), the rod-shaped holder (20) to which the detection unit (a) is attached, and the lead terminal (12) connected to the lead terminal (12) and drawn out in the lead-out direction. A rotation detection sensor (P) comprising a cable (6) for transmitting an electric signal to the outside, and a resin coating (4) covering a part of the detection unit (a) and the cable (6),
The magnetoelectric transducer (11) is placed and fixed on the mounting plane (21) of the holder (20) with its plate surface (11d), and the pair of lead terminals (12, 12). Are parallel to the plate surface (11d) of the magnetoelectric transducer (11), and the width (t) of the holder (20) in the direction along the plate surface (11d) is the magnetoelectric transducer (11). A rotation detection sensor characterized by having a width (T) or less in the direction along the plate surface (11d).   The plate surface (11d) of the magnetoelectric transducer (11) is set as the drawing direction of the cable (6), and the holder (20) has a rod-shaped cross section of the width (T) of the magnetoelectric transducer (11). The symmetric shape with respect to the central axis (l), and the width (t) is gradually narrowed away from the magnetoelectric transducer (11) in the plate thickness direction. Rotation detection sensor.

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