JP2009025062A - Rotation detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation detection sensor which is superior in sealing performance to prevent the entry of water from the outside, will not cause internal thermal strain caused by internal heat generation and temperature changes in the external environment and damage to a sensor component and its peripheral circuit caused by external force, and can be manufactured at low cost. <P>SOLUTION: The rotation detection sensor is fixed to a sensor fixing member 7 mounted to a wheel bearing and detects the rotation of a rotating race of the wheel bearing. A sensor unit B comprises a magnetic sensor element 1 for detecting an object to be detected of the rotating race, a cable 10 for extracting the output signal of the sensor element 1 to the outside, and a substrate 11, to which the sensor element 1 and one end of the cable 10 are connected and which has a conductive part 3 for electrically connecting an electrode 2 of the sensor element 1 and a core 4 of the cable 10. A notch 13 is provided in the vicinity of the electrode 2 of the sensor element 1 in the substrate 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotation detection sensor used as, for example, an automobile ABS sensor.

  ABS sensor (axle rotation sensor for anti-lock brake system) used by attaching to a hub bearing of an automobile is provided with a magnet or a metal body on a rotating wheel of a hub bearing, and a magnetic pickup, a hall sensor, an MR sensor, etc. are opposed to the magnet or metal body. The magnetic sensor is arranged. ABS sensors are required to have mechanical strength, waterproofness, weather resistance, chemical resistance, and the like. Therefore, it is used as a sensor unit structure by overmolding the sensor component with resin or the like.

As a method for overmolding a sensor component, for example, Patent Document 1 proposes a method in which a sensor component is fixed in advance to a sensor fixing holder and is overmolded with a resin.
JP 2000-88984 A

The sensor unit structure for an ABS sensor by the conventional overmolding method has the following problems.
-Since the molding material is resin, the adhesiveness between the built-in product such as sensor parts and sensor fixing holder and the molding material cannot be expected.
-Due to the self-heating of sensor parts, which are electronic parts, and changes in the environmental temperature, there is a risk of a gap between the built-in product and the mold material, resulting in a problem with waterproofness.
-Even when an external force is applied to the sensor unit structure and plastic deformation occurs in the molding material, there is a problem in waterproofness because a gap is formed between the built-in product and the molding material.
-Since the molding material made of resin has low deformation capacity, when an external force is applied to the sensor unit structure, the built-in product may be damaged or deformed by the external force acting directly on the built-in product.
・ Since the mold material made of resin has poor vibration absorption, there is a problem with durability against external vibration.
-If an external force is applied that causes the signal cable section that is a signal transmission path from the sensor unit structure to the outside to bend, the external force may be transmitted to the sensor device inside the sensor unit structure, resulting in failure.

  As a countermeasure for solving such a problem, a sensor unit includes a sensor element, a cable for taking out an output signal thereof, and a substrate having a conductive portion that electrically connects an electrode portion of the sensor element and a core wire of the cable. Rotation detection that maintains waterproofness and earthquake resistance by fixing this sensor unit to the sensor fixing member and providing a molding part formed by molding a thermoplastic elastomer or rubber material around the sensor unit It is conceivable to manufacture the sensor at a low cost.

  However, even in this configuration, the electrode portion that extends from the sensor element and is connected to the conductive portion of the substrate is disposed in the middle of the electrode portion so that it is a thermoplastic that is a molding material when molding the molding portion. There is a possibility that the elastomer or the rubber material does not spread over the entire sensor element electrode portion. As a result, the sensor element electrode part is not molded by the molding part, and the waterproofness of the sensor element electrode part may not be maintained.

  The object of the present invention is excellent in sealing performance to prevent the ingress of water from the outside, the internal heat distortion due to internal heat generation and the temperature change of the external environment, and the external force do not cause damage to the sensor component and its peripheral circuit part. It is to provide a rotation detection sensor that can be manufactured at low cost.

  A rotation detection sensor according to the present invention is a rotation detection sensor that is fixed to a sensor fixing member that is attached to a wheel bearing and detects the rotation of a rotating wheel of the wheel bearing, and is an annular cover that is provided concentrically with the rotating wheel. A magnetic sensor element for detecting the detection body, a cable for taking out an output signal of the sensor element to the outside, the sensor element and one end of the cable are attached, and the electrode part of the sensor element and the core wire of the cable And a substrate having a conductive portion that electrically connects the sensor unit, a notch is provided in the vicinity of the substrate where the electrode portion of the sensor element is disposed, and the sensor unit is connected to the sensor by the substrate. It is characterized in that a molding part formed by molding a molding material is provided so as to be fixed to a fixing member, cover the sensor unit.

According to the configuration of the present invention, the following effects can be obtained.
・ Since the sensor unit consisting of sensor components such as sensor elements, cables, and substrates is molded with an elastic mold material, when the vibration detection or external force acts on the rotation detection sensor, the mold material must absorb the vibration or external force. Thus, it is possible to protect the sensor component by reducing the influence on the sensor component.
-If the mold material is an elastic thermoplastic elastomer or rubber material, the sensor component and the mold material may have different thermal expansion and contraction due to changes in environmental temperature and the self-heating of the sensor component, which is an electronic component. However, the difference can be absorbed by the elasticity of the molding material, so that a gap is not generated between the sensor component and the molding material, and the waterproof property can be maintained.
・ In particular, since the notch is provided in the vicinity of the electrode part of the sensor element on the substrate, when the molding material is provided by molding the molding material so as to cover the sensor unit, the entire electrode part of the sensor element is provided. Thus, the molding material can be easily spread, and the electrode portion can be more reliably molded. As a result, even if water enters from between the sensor fixing member and the molding part, the waterproofness of the electrode part can be reliably maintained.

When the mold material is a rubber material, the molding can be performed using a mold. In that case, the mold consists of an upper mold and a lower mold, and the sensor unit and the rubber material are put between the upper mold and the lower mold, and pressure is applied between both molds while heating the upper mold and the lower mold. Thus, the molding part may be compression molded.
If molding of the molding part is compression molding using a mold, a large number of rotation detection sensors can be manufactured by one molding, and the cost can be reduced. Further, if the mold is composed of an upper mold and a lower mold, the sensor unit can be easily positioned and an appropriate pressure can be applied to the molding material. Note that a mold by injection molding requires a nozzle that allows molten resin to flow in, a runner that guides the molten resin to a hollow portion that becomes a molded product, and an inlet (gate) to the hollow portion. In order to smooth the flow of the melted portion passing through them and increase the yield, the number of production at one time is appropriate from several to about ten and the number of molding at one time is limited. In contrast, molding by compression molding can produce a large amount of rotation detection sensor by one molding.

When the molding material is a thermoplastic elastomer, the molding can be injection molding using a mold. In that case, the molding unit is injection-molded by placing a sensor unit in the mold and injecting a thermoplastic elastomer into the mold.
Even when the mold material is a rubber material, the molding may be injection molding using a mold. In that case, the molding unit is injection-molded by placing a sensor unit in the mold and injecting a rubber material into the mold.
If the molding part is molded by injection molding, manufacturing is easy and productivity is excellent.

Further, when the mold material is a rubber material, the molding is performed using a mold composed of an upper mold and a lower mold, and the sensor unit and the rubber material are preliminarily attached to either the upper mold or the lower mold. And the molding part may be molded by injection molding a rubber material from the other mold.
When the molding part is molded in this way, in addition to the effects of molding the molding part by the injection molding alone, a sensor unit and a rubber material are put in advance in either the upper mold or the lower mold. As a result, the operational effect that the positioning of the sensor unit is facilitated can be obtained.

  As the sensor element, a Hall element, a magnetoresistive effect element (MR element), a giant magnetoresistive effect element (GMR element), a tunnel magnetoresistive element (TMR element), or a coil can be used. Whichever is used, a good rotation detection sensor is obtained.

The sensor fixing member may be attached to a fixed wheel of a wheel bearing or a peripheral member thereof.
When the sensor fixing member is attached to the fixed wheel of the wheel bearing or its peripheral member, it is not necessary to provide another member for attaching the rotation detection sensor, and the configuration is simplified.

The sensor fixing member may also serve as a cover that covers an end surface of the wheel bearing.
Also in this case, it is not necessary to provide a separate member for attaching the rotation detection sensor, and the configuration is simplified.

  A rotation detection sensor according to the present invention is a rotation detection sensor that is fixed to a sensor fixing member that is attached to a wheel bearing and detects the rotation of a rotating wheel of the wheel bearing, and is an annular cover that is provided concentrically with the rotating wheel. A magnetic sensor element for detecting the detection body, a cable for taking out an output signal of the sensor element to the outside, the sensor element and one end of the cable are attached, and the electrode part of the sensor element and the core wire of the cable And a substrate having a conductive portion that electrically connects the sensor unit, a notch is provided in the vicinity of the substrate where the electrode portion of the sensor element is disposed, and the sensor unit is connected to the sensor by the substrate. Sealing performance to prevent intrusion of water from the outside because it is fixed to a fixing member, covers the sensor unit, and has a molding part formed by molding a molding material Excellent internal thermal distortion due to temperature changes in the internal heat generation and the external environment, and sensor parts and damage is not caused in the peripheral circuit portion by an external force, yet inexpensive to manufacture.

  An embodiment of the present invention will be described with reference to FIGS. The rotation detection sensor A is configured by fixing a sensor unit B composed of a plurality of sensor components to a sensor fixing member 7 and covering the sensor unit B with a molding portion 8. This rotation detection sensor A is used in combination with an object to be detected such as a magnetic encoder 45.

  The sensor unit B includes a magnetic sensor element 1, a cable 10 for taking out an output signal of the sensor element 1, and a substrate 11 to which the sensor element 1 and one end of the cable 10 are attached. The substrate 11 has a conductive portion 3 (FIG. 3) formed on the surface of an insulating substrate made of resin or the like by printed wiring or the like. The sensor element 1 is, for example, a Hall element, a magnetoresistive effect element (MR element), a giant magnetoresistive effect element (GMR element), a tunnel magnetoresistive element (TMR element), a coil, or another magnetic sensor element. Consists of. In the case of this embodiment, the cable 10 has two cable core wires 4. Each cable core wire 4 is covered with an insulating coating 5 in an electrically insulated state, and each insulating coating 5 is covered with a cable cover 6. It is supposed to be.

  The electrode part 2 of the sensor element 1 is electrically connected to the conductive part 3 of the substrate 11, and the cable core 4 of the cable 10 is also electrically connected to the conductive part 3. The conductive part 3 is made of a metal having good electrical conductivity such as copper foil. That is, the electrode part 2 of the sensor element 1 and the core wire 4 of the cable 10 are electrically connected via the conductive part 3 of the substrate 11. The conductive portion 3 is attached to the front surface side (FIG. 3A) of the substrate 11, and the sensor element 1 is attached to the back surface side (FIG. 3B) of the substrate 11. 2 extends from the back side to the front side of the substrate 11 through the outside of the substrate 11. In the vicinity of the substrate 11 where the electrode portion 2 of the sensor element 1 is disposed, a notch portion 13 for increasing the gap between the substrate 11 and the electrode portion 2 is provided. In the example shown in the figure, the notch 13 has a rectangular shape whose opening width is wider than the depth, and is located across the two electrodes 2. However, a plurality of the notches 13 may be provided, and the shape Can have various shapes such as a U shape, a V shape, and a semicircular shape. The electrode part 2 and the conductive part 3 are electrically connected by pressure bonding, soldering, thermocompression bonding, or other joining methods. The cable core wire 4 and the conductive portion 3 are electrically connected by pressure bonding, soldering, or other joining methods.

  The sensor fixing member 7 also serves as a cover for covering the end face of the wheel bearing (see FIG. 7), and is an annular metal product centered on the central axis of the wheel bearing. The sensor fixing member 7 includes a stepped cylindrical portion 7a having a large diameter portion 7aa and a small diameter portion 7ab, and a flange portion 7b extending from the edge of the small diameter portion 7ab of the cylindrical portion 7a toward the inner diameter side. As shown in FIG. 2, the sensor unit B is fixed to the sensor fixing member 7 by fixing the substrate 11 to the flange portion 7 b of the sensor fixing member 7 with the fixture 12. An opening 7 c is formed in the flange portion 7 b, and the sensor element 1 protrudes through the opening 7 c to the side opposite to the fixed surface of the substrate 11. Various fixtures such as pins, screws, and rivets can be used as the fixture 12.

  As shown in FIGS. 1 (A) and 1 (C), a part of the sensor fixing member 7 is provided with a clamp portion 9 for winding and fixing a portion near the end of the cable 10 on the sensor unit B side. ing. In this embodiment, the clamp portion 9 is integrated with the sensor fixing member 7, but may be a separate member.

  The molding material used for the mold of the sensor unit B is made of a material having rubber elasticity, and a rubber material or a thermoplastic elastomer is suitable. As the rubber material, nitrile rubber or fluororubber is desirable. These are excellent in heat resistance, low temperature characteristics, and oil resistance. Rubber materials other than the above may be used. As the thermoplastic elastomer, vinyl chloride, ester and amide are desirable. These are excellent in heat resistance and oil resistance.

  When the mold material is a rubber material, the molding of the mold material can be compression molding using a mold. For example, as shown in FIG. 4A, the compression molding using a mold is performed between a sensor unit B, a sensor fixing member 7 (not shown), and a mold material 22 between an upper mold 20 and a lower mold 21 which are molds. Then, as shown in FIG. 5B, the upper mold 20 and the lower mold 21 are heated and pressure is applied between both molds. Since the substrate 11 is fixed to the sensor fixing member 7, the position of the sensor unit B does not move due to the internal pressure in the molds 20 and 21 during compression molding, and the sensor unit B can be easily positioned. Further, when the mold is composed of the upper mold 20 and the lower mold 21, the positioning of the sensor unit B is easy, and an appropriate pressure can be applied to the molding material. Furthermore, if molding of the molding part 8 is compression molding using a mold, a large amount of rotation detection sensor A can be manufactured by one molding, and the cost can be reduced.

  When the molding material is a thermoplastic elastomer, the molding of the molding material is preferably injection molding using a mold. In the injection molding using a mold, for example, as shown in FIG. 5A, a sensor unit B and a sensor fixing member 7 (not shown) are placed in molds 20 and 21 that can be divided. By injecting the molding material 22 into the molds 20 and 21 through the molding material injection hole 23, the molding material 22 is molded as shown in FIG. In FIG. 2A, the sensor unit B is fixed at a predetermined position by a sensor fixing member 7 (not shown). When the mold material is a rubber material, it can be similarly molded by injection molding. This injection molding is easy to manufacture and has excellent productivity.

  When the molding material is a rubber material, the molding material may be molded by the method shown in FIG. That is, a mold composed of an upper mold 20 and a lower mold 21 is used, and a sensor unit B is previously placed in either the upper mold or the lower mold (the lower mold 21 in the illustrated example) as shown in FIG. Then, the sensor fixing member 7 (not shown) and the mold material 22 are inserted, and the mold material 22 is inserted from the mold material injection hole 23 of the other mold (the upper mold 20 in the illustrated example) as shown in FIG. Is injected into the molds 20 and 21, and the molding material 22 is injection molded. When the molding part 8 is molded in this way, in addition to the operational effects of molding by the injection molding alone, the sensor unit B and the molding material 22 are put in the lower mold 21 in advance, thereby positioning the sensor unit B. The effect that it becomes easy is obtained.

In the rotation detection sensor A having the above-described configuration, since the sensor unit B is molded with the molding material 22 made of an elastic thermoplastic elastomer or rubber material, when vibration or external force acts on the rotation detection sensor A, the vibration or external force is detected. Since the molding part 8 absorbs the influence of the sensor unit B on each sensor part, the sensor part can be protected. In addition, since the molding part 8 is made of an elastic thermoplastic elastomer or rubber material, the thermal expansion / contraction of the sensor part and the molding part 8 differ depending on changes in environmental temperature and self-heating of the sensor part which is an electronic part. Even in the case of occurrence of such a phenomenon, the difference can be absorbed by the elasticity of the molding portion 8, and a gap can be prevented from being generated between the sensor component and the molding portion 8, and waterproofness can be maintained.
In particular, since the notch 13 is provided in the substrate 11 in the vicinity of the electrode portion 2 of the sensor element 1, a molding material (thermoplastic elastomer or rubber material) is molded so as to cover the sensor unit B. When the portion 8 is provided, the molding material can easily spread over the entire electrode portion 2 of the sensor element 1, and the electrode portion 2 can be more reliably molded. As a result, even if water enters from between the sensor fixing member 7 and the molding part 8, the waterproofness of the electrode part 2 can be reliably maintained.

In this embodiment, since the sensor fixing member 7 also serves as a cover for the wheel bearing, the rotation detection sensor A can be easily positioned and the number of parts can be reduced. Further, since the sensor fixing member 7 is made of metal, when the molding material is a rubber material, the adhesion between the sensor fixing member 7 and the molding portion 8 is good, and the rotation detection sensor A as a whole has a strong structure. Can do.
Furthermore, since the portion near the end on the sensor unit B side of the cable 10 is fixed to the sensor fixing member 7 by the clamp portion 9, even when an external force is applied to the cable 10, the clamp portion 9 receives a load, No load is applied to the sensor unit B or the molding unit 8.

  FIG. 7 shows a wheel bearing device provided with the rotation detection sensor of the present invention. In this wheel bearing device, a rotation detection sensor / fixing member mounting body C formed by fixing the rotation detection sensor A to the sensor fixing member 7 is attached to the bearing portion 30. In the following description, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side.

  The bearing portion 30 includes an outer member 31 in which a double row rolling surface 33 is formed on the inner periphery, an inner member 32 in which a rolling surface 34 that faces each of the rolling surfaces 33 is formed, and these outer members. 31 and a double row rolling element 35 interposed between the rolling surfaces 33 and 34 of the inner member 32. The rolling elements 35 in each row are held by a holder 36. Both ends of the bearing space between the outer member 31 and the inner member 32 are sealed by sealing devices 37 and 38, respectively.

  The outer member 31 is a fixed wheel, is an integral part, and is provided with a flange 31a on the outer periphery for attachment to a knuckle (not shown) extending from the suspension device of the vehicle body. The inner member 32 is a rotating wheel, and includes a hub wheel 39 having a wheel mounting flange 39a on the outboard side, and an inner ring 40 fitted to the outer periphery of the inboard side end of the hub wheel 39. Become. The hub ring 39 and the inner ring 40 are formed with the rolling surfaces 34 of the respective rows. The inner member 32 has an axial through hole 41 at the center, and a stem portion (not shown) of one joint member of the constant velocity joint is inserted into the through hole 41.

  In the sealing device 38 on the inboard side of the sealing devices 37 and 38, a magnetic encoder 45 as a detection object is incorporated. The magnetic encoder 45 is provided with a multipolar magnet 45b on a side plate portion of a ring member 45a having an L-shaped cross section. The ring member 45a includes a cylindrical portion that is attached to the outer periphery of the inner member 2 by press fitting, and the side plate portion that extends from the inboard side end of the cylindrical portion to the outer diameter side. The multipolar magnet 45b is a member formed with alternating magnetic poles N and S in the circumferential direction, and is made of a rubber magnet, a plastic magnet, a sintered magnet, or the like. In this embodiment, the magnetic encoder 45 also serves as a component of the inboard side sealing device 38 and functions as a slinger.

The sensor fixing member 7 is configured such that the cylindrical portion large diameter portion 7aa is fitted to the outer peripheral surface inboard side of the outer member 31, and the step surface of the cylindrical portion large diameter portion 7aa and the small diameter portion 7ab is provided on the outer member 31. It is attached to the outer member 31 in contact with the end face on the inboard side. The sensor fixing member 7 also serves as a cover for the end face on the inboard side of the wheel bearing. In a state where the sensor fixing member 7 is attached, the rotation detection sensor A is positioned facing the magnetic encoder 45.
When the inner member 32, which is a rotating wheel, rotates, the sensor element 1 detects the magnetic poles N and S of the magnetic encoder 45 that rotates with the inner member 32. The detection signal is transmitted to the automobile electric control unit (not shown) via the cable 10, and the rotation speed is calculated from the detection signal of the sensor element 1 by the electric control unit.

The rotation detection sensor of this embodiment is of a type opposed to the magnetic encoder 45 in the axial direction, but the present invention can be applied to a type opposed to the magnetic encoder 45 in the radial direction. As the detected object, a gear-type pulse ring may be used instead of the magnetic encoder 45.
Further, the magnetic encoder 45 or the pulse ring as a detection target may be attached to a wheel for an automobile.
Furthermore, in this embodiment, the sensor fixing member 7 is directly attached to the fixed wheel, but may be attached to the fixed wheel via another member.

(A) is a front view of the rotation detection sensor concerning one Embodiment of this invention, (B) is IB-IB arrow sectional drawing, (C) is IC-O arrow sectional drawing. It is the II section enlarged view of FIG. 1 (A). (A) is a front view of the connection part of a sensor element, a cable, and a board | substrate, (B) is the back view. It is explanatory drawing which shows the shaping | molding method of a mold material. It is explanatory drawing which shows the shaping | molding method of a different mold material. Furthermore, it is explanatory drawing which shows the shaping | molding method of a different mold material. It is sectional drawing of the wheel bearing apparatus which provided the rotation detection sensor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sensor element 2 ... Electrode part 3 ... Conductive part 4 ... Cable core wire 7 ... Sensor fixing member 8 ... Molding part 10 ... Cable 11 ... Board | substrate 13 ... Notch part 20 ... Upper mold | die (mold)
21 ... Lower mold (mold)
22 ... Mold material 45 ... Magnetic encoder (detected body)
A ... Rotation detection sensor B ... Sensor unit

Claims (8)

  A rotation detection sensor which is fixed to a sensor fixing member attached to a wheel bearing and detects the rotation of a rotating wheel of the wheel bearing, and is a magnetic sensor which detects an annular detection object provided concentrically with the rotating wheel. A sensor element, a cable for taking out an output signal of the sensor element to the outside, a conductive element for attaching the sensor element and one end of the cable, and electrically connecting the electrode part of the sensor element and the core wire of the cable A sensor unit is configured with a substrate having a portion, a notch portion is provided in the vicinity of the electrode portion of the sensor element on the substrate, and the sensor unit is fixed to the sensor fixing member with the substrate. A rotation detection sensor comprising a molding part formed by molding a molding material.   In Claim 1, the molding is molding using a mold, the mold is composed of an upper mold and a lower mold, and a mold material composed of the sensor unit and a rubber material is inserted between the upper mold and the lower mold, A rotation detection sensor in which the molding part is compression-molded by applying pressure between both molds while heating the upper mold and the lower mold.   2. The molding according to claim 1, wherein the molding is injection molding using a mold, and the molding part is injection molded by placing a sensor unit in the mold and injecting a thermoplastic elastomer into the mold. Rotation detection sensor.   2. The rotation according to claim 1, wherein the molding is injection molding using a mold, and the molding part is injection molded by placing a sensor unit in the mold and injecting a rubber material into the mold. Detection sensor.   2. The molding according to claim 1, wherein the molding is performed using a mold composed of an upper mold and a lower mold. A rubber material is previously placed in one of the upper mold and the lower mold, and the rubber material is injected from the other mold. A rotation detection sensor formed by molding the molding part.   6. The rotation detection sensor according to claim 1, wherein the sensor element is a Hall element, a magnetoresistive element, a giant magnetoresistive element, a tunnel magnetoresistive element, or a coil.   The fixed detection sensor according to any one of claims 1 to 6, wherein the sensor fixing member is attached to a fixed ring of a wheel bearing or a peripheral member thereof.   8. The rotation detection sensor according to claim 1, wherein the sensor fixing member also serves as a cover that covers an end surface of the wheel bearing.

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