JP2008275490A - Rotation detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation detection sensor which has excellent seal performance for preventing entering of water from outside, prevents damages on a sensor component and its peripheral circuit part by heat distortion of an inside caused by internal heat generation and a temperature change of an external environment, and external force, and is easy to manufacture. <P>SOLUTION: The rotation detection sensor A is fixed to a sensor fixation member 7 attached to a bearing for a wheel, and detects rotation of a rotating ring of the bearing for the wheel. A sensor unit B has a magnetic type sensor element 1 for detecting a detection target body on the rotating ring, a cable 10 for taking out an output signal of the sensor element 1 to an external, and an electrode terminal member 3 for electrically connecting an electrode section 2 of the sensor element 1 and a core wire 4 of the cable 10. The sensor unit B is placed at a predetermined position on the sensor fixation member 7, and a molding section 8 made by molding thermoplastic elastomer or rubber material is provided around the entire sensor unit B and a part of the sensor fixation member 7. A clamp section 9 is provided to fix the cable 10 to the sensor fixation member 7 at a position away from the molding section 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  The ABS sensor (axle rotation sensor) used by mounting on a hub bearing of an automobile is provided with a magnet or a metal body on the rotating ring of the hub bearing, and a magnetic sensor such as a magnetic pickup, a hall sensor, or an MR sensor is arranged opposite to the magnet. The configuration is 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 a resin, it is not possible to expect adhesion between the built-in product such as a sensor component or a sensor fixing holder and the molding material.
-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 a 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 in 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.
A conventional 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 increase the yield by smoothing the flow of the molten resin passing through these, the number of manufactured parts at one time is appropriate from several to about ten, and the number of molded parts at one time is limited.

  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 is simple to manufacture.

  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 sensor unit comprising a magnetic sensor element for detecting a detection body, a cable for outputting an output signal of the sensor element to the outside, and an electrode terminal member for electrically connecting an electrode portion of the sensor element and a core wire of the cable The molding unit is formed by arranging the sensor unit at a predetermined position with respect to the sensor fixing member, and molding a thermoplastic elastomer or a rubber material around the entire sensor unit and a part of the sensor fixing member. And a clamp portion for fixing the cable to the sensor fixing member at a location away from the molding portion.

According to the configuration of the present invention, the following effects can be obtained.
・ Since the sensor unit consisting of each sensor component of the sensor element, cable, and electrode terminal member is molded with an elastic thermoplastic elastomer or rubber mold material, when vibration or external force is applied to the rotation detection sensor, By absorbing the vibration and external force, the mold material can reduce the influence on the sensor component and protect the sensor component.
-Since the sensor unit is fixed to the sensor fixing member by molding the whole of the sensor unit and a part of the sensor fixing member with a molding material, another process of fixing the sensor unit to the sensor fixing member Is unnecessary.
・ Since the molding material is an elastic thermoplastic elastomer or rubber material, thermal expansion / contraction of the sensor component and the molding material differed due to changes in environmental temperature and self-heating of the sensor component, which is an electronic component. Even in such a case, 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 waterproofness can be maintained.
-In particular, when the molding material is a rubber material, the adhesion between the molding material and the metal of the sensor component is good, and waterproofness can be ensured.
・ Because the cable is fixed to the sensor fixing member at a location away from the molding part by the clamp, no load is applied to the sensor unit even if an external force is applied to the cable. I can prevent it.

The molding can be performed using a mold. In this case, the mold is composed of an upper mold and a lower mold. Between the upper mold and the lower mold, the entire sensor unit, a part of the sensor fixing member, and a thermoplastic elastomer or a rubber material are put into an upper mold. The molding part may be molded by applying pressure between the two molds while heating the lower mold and the lower mold.
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. 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 thermoplastic elastomer or rubber material.

  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 wheel bearing cover.
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 sensor unit comprising a magnetic sensor element for detecting a detection body, a cable for outputting an output signal of the sensor element to the outside, and an electrode terminal member for electrically connecting an electrode portion of the sensor element and a core wire of the cable The molding unit is formed by arranging the sensor unit at a predetermined position with respect to the sensor fixing member, and molding a thermoplastic elastomer or a rubber material around the entire sensor unit and a part of the sensor fixing member. And provided with a clamp part for fixing the cable to the sensor fixing member at a location away from the molding part. Excellent sealing performance to prevent the entry, internal heat distortion due to temperature changes in the internal heat generation and the external environment, and by an external force, the sensor component and without causing damage to the peripheral circuit portion, moreover manufacture is simple. Further, since the 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.

  An embodiment of the present invention will be described with reference to FIGS. In this rotation detection sensor A, a sensor unit B composed of a plurality of sensor components is arranged at a predetermined position with respect to the sensor fixing member 7, and the sensor unit B is arranged around the entire sensor unit B and a part of the sensor fixing member 7. The molding part 8 is provided by molding the periphery of B. 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 electrically connects the magnetic sensor element 1, the cable 10 that extracts the output signal of the sensor element 1 to the outside, the electrode portion 2 of the sensor element 1, and the core wire 4 of the cable 10. It consists of an electrode terminal member 3. The electrode terminal member 3 is made of a metal having good electrical conductivity such as copper foil. The electrode part 2 and the electrode terminal member 3 of the sensor element 1 and the cable core wire 4 and the electrode terminal member 3 are all electrically connected by pressure bonding, soldering, or other joining methods.

  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 sensor fixing member 7 also serves as a cover that covers the end face of the wheel bearing (see FIG. 4), and is a metal product formed by sheet metal processing, for example. The sensor fixing member 7 includes a stepped annular 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 annular portion 7a toward the inner diameter side. As shown in FIG. 2, the sensor unit B is disposed in the opening 7 c formed in the flange portion 7 b of the sensor fixing member 7, and the sensor unit B is disposed around the entire sensor unit B and a part of the sensor fixing member 7. The sensor unit B is positioned and fixed with respect to the sensor mounting member 7 by molding the periphery of B with a molding material.

  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. Yes. The position of the clamp part 9 is a position slightly away from the molding part 8. In this embodiment, the clamp portion 9 is integrated with the sensor fixing member 7, but may be a separate member.

  The sensor unit B and the sensor fixing member 7 are molded by compression molding a molding material. The molding material is made of a material having rubber elasticity, and a rubber material or a thermoplastic elastomer can be used. 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.

  The compression molding of the molding material is preferably compression molding using a mold. For example, as shown in FIG. 3A, the entire sensor unit B, a part of the sensor fixing member 7 and the molding material 22 are inserted between the upper mold 20 and the lower mold 21 which are molds. As shown in FIG. 5B, the upper mold 20 and the lower mold 21 are heated and molded by applying pressure between the two molds. If the mold is composed of the upper mold 20 and the lower mold 21, the positioning of the sensor unit B and the like is easy, and an appropriate pressure can be applied to the thermoplastic elastomer or rubber material. Further, 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.

  In the rotation detection sensor A having the above-described configuration, since the sensor unit B is molded with a mold material made of an elastic thermoplastic elastomer or rubber material, when vibration or external force is applied to the rotation detection sensor A, the vibration or external force is molded. The absorption by the part 8 can reduce the influence on each sensor component of the sensor unit B and protect the sensor component. In addition, since the molding part 8 is made of an elastic thermoplastic elastomer or rubber material, the thermal expansion / shrinkage of the sensor component and the molding part 8 differ in degree due to changes in environmental temperature and self-heating of the sensor component which is an electronic component. Even if this occurs, the difference can be absorbed by the elasticity of the molding part 8, preventing a gap from being formed between the sensor component and the molding part 8, and maintaining waterproofness. In particular, when the molding material is a rubber material, the adhesiveness between the molding part 8 and the metal of the sensor component is good, and waterproofness can be ensured.

  Since the sensor fixing member 7 also serves as a wheel bearing cover, the positioning of the rotation detection sensor A with respect to the detected object such as the magnetic encoder 45 is easy, and the number of components 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.

By molding and molding the molding unit 8, the sensor unit B is positioned and fixed with respect to the sensor mounting member 7. Therefore, a separate process for fixing the subunit B to the sensor fixing member 7 is unnecessary, and the rotation detection sensor A is simplified. Can be produced. Further, since the fixing member is unnecessary, the configuration of the rotation detection sensor A can be simplified.
Since the fixing member is not used as described above, if the external force is applied to the cable 10 as it is, the sensor unit B may move and a load may be applied to the sensor unit B. However, in this rotation detection sensor A, the cable 10 is fixed to the sensor fixing member 7 at a position slightly away from the molding portion 8 by the clamp portion 9, so that the portion of the cable 10 ahead of the clamp portion 9 is The movement is restrained and the sensor unit B is not loaded. Thereby, failure of each sensor component which constitutes sensor unit B can be prevented.

  FIG. 4 shows a wheel bearing device provided with the rotation detection sensor of the present invention. This wheel bearing device has a rotation detection sensor A attached to a 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 annular portion large diameter portion 7aa is fitted to the outer peripheral surface inboard side of the outer member 1, and the step surface of the annular portion large diameter portion 7aa and the small diameter portion 7ab is disposed on the outer member. 1 is attached to the outer member 1 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 1 that is a rotating wheel rotates, the sensor element 1 detects the magnetic poles N and S of the magnetic encoder 45 that rotates together with the inner member 1. 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 that faces the magnetic encoder in the axial direction, but the present invention can also be applied to a type that faces the magnetic encoder in the radial direction. As an object to be detected, a pulse coder may be used instead of the magnetic encoder.
Further, a magnetic encoder or pulse coder as a detected object 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) Front view of rotation detection sensor according to embodiment of the present invention, (B) is an IB-IB sectional view, and (C) is an IC-O sectional view. It is the elements on larger scale of FIG. It is explanatory drawing which shows the method of compression molding. 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 ... Electrode terminal member 4 ... Cable core wire 7 ... Sensor fixing member 8 ... Molding part 9 ... Clamp part 10 ... Cable 20 ... Upper mold (mold)
21 ... Lower mold (mold)
22 ... Mold material 45 ... Magnetic encoder (detected body)
A ... Rotation detection sensor B ... Sensor unit

Claims (6)

  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 unit is composed of a sensor element, a cable for taking out an output signal of the sensor element to the outside, and an electrode terminal member for electrically connecting the electrode portion of the sensor element and the core wire of the cable. Placed at a predetermined position with respect to the sensor fixing member, a molding part formed by molding a thermoplastic elastomer or a rubber material is provided around the whole sensor unit and a part of the sensor fixing member, and is separated from the molding part. A rotation detection sensor, wherein a clamp portion for fixing the cable to the sensor fixing member is provided at a place where the cable is connected.   The rotation detection sensor according to claim 1, wherein the molding is molding using a mold.   The mold according to claim 2, wherein the mold includes an upper mold and a lower mold, and the entire sensor unit, a part of the sensor fixing member, and a thermoplastic elastomer or rubber material are inserted between the upper mold and the lower mold. A rotation detection sensor in which the molding part is molded by applying pressure between both molds while heating the upper mold and the lower mold.   4. The rotation detection sensor according to claim 1, wherein the sensor element is a Hall element, a magnetoresistive effect element, a giant magnetoresistive effect element, a tunnel magnetoresistive element, or a coil.   5. The rotation detection sensor according to claim 1, wherein the sensor fixing member is attached to a fixed wheel of a wheel bearing or a peripheral member thereof.   6. 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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