JP2009069000A - Sensor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor unit having high reliability of a product, capable of reducing the manufacturing cost, preventing penetration of water from the outside, and preventing infiltration of water into a sensor and a peripheral circuit resulting from thermal strain inside the sensor unit caused by the temperature change of the outside. <P>SOLUTION: This sensor unit is equipped with the sensor 4 and a mold material 3 comprising plastics, a thermoplastic elastomer, or a material showing rubbery elasticity, and a cable. In the sensor unit formed by impregnating insulating liquid LQ into a gap between the sensor 4 and the mold material 3, or the like, a water-repellent coat hc, such, as Teflon (R) coating for preventing penetration of water into the gap or the like is applied, to at least a part of the mold material 3 and the cable. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sensor unit applied to, for example, an antilock brake system (ABS) sensor for automobiles.

  A technique for manufacturing a sensor and peripheral parts by resin overmolding (insert molding) has been put to practical use (see Patent Document 1). In an axle rotation sensor (ABS sensor) used for mounting on a hub bearing of an automobile, a magnet body or a metal body is disposed on a rotating wheel of the hub bearing, and a magnetic type such as a magnetic pickup, a hall sensor, or a magnetoresistive element is opposed thereto. It is the structure which arrange | positions a sensor. The ABS sensor is used as a sensor unit structure by overmolding sensor components.

  In the prior art, a sensor component is fixed in advance to a sensor holder for fixing a sensor, and resin is overmolded (secondary molding). In automobile parts, performances such as mechanical strength, waterproofness, weather resistance, chemical resistance and the like are required, and such a mold is required.

JP 2000-88984 A

The prior art has the following problems.
(1) Adhesiveness between the molding material and the component to be incorporated cannot be expected.
(2) Due to the self-heating of the built-in electronic component and the change in the environmental temperature, a gap is generated between the mold material and the built-in component due to a difference in thermal expansion, and there is a problem in waterproofness.
(3) Even when an external force is applied to the molded sensor unit and plastic deformation occurs in the molding material, a gap is generated between the molding material and the built-in component, and there is a problem in waterproofness.

  In sensor parts such as ABS sensors that are mounted and used on automobile parts, especially in hub bearings, they are exposed to the road surface and exposed to salt mud water, and in severe environments where a large temperature change from 100 degrees to minus tens of degrees occurs. It is installed at the lower part of the suspension and is greatly affected by vibrations caused by vehicle travel. The malfunction of the ABS sensor has a great influence on the safety of vehicle travel. Therefore, it is necessary to avoid as much as possible the deterioration of waterproofness due to the adhesiveness between the molding material and the built-in parts, the difference in thermal expansion, the generation of gaps due to external force, etc., and the durability against damage and vibration due to external force It is strongly desired that the property be excellent. Such various strict demands are difficult to satisfy with a conventional resin molded sensor unit.

  The object of the present invention is to prevent the ingress of water from the outside, and further prevent the intrusion of water into the sensor and the peripheral circuit due to the thermal distortion inside the sensor unit due to the temperature change of the outside. It is an object of the present invention to provide a sensor unit that is high in cost and can reduce manufacturing costs.

  The sensor unit of the present invention is electrically connected to the sensor device, a covering material for covering the sensor device, the covering material being made of plastic, a thermoplastic elastomer, or a material exhibiting rubber elasticity, and the sensor device. A cable for outputting sensing information from the sensor device, and a gap between the sensor device and the covering material is impregnated with an insulating liquid, and at least a part of the covering material and the cable includes It is characterized by applying a water-repellent coat that prevents moisture from entering the gaps.

According to this configuration, the sensor device is covered with a covering material made of a material exhibiting plastic elasticity, thermoplastic elastomer, or rubber elasticity. The cable outputs sensing information from the sensor device. By impregnating the gap between the sensor device and the covering material with the insulating liquid through the lipophilic film, it is possible to prevent moisture from entering the gap from the outside. By simply impregnating the gap with an insulating liquid in advance, it is possible to reliably and easily prevent moisture from entering from the outside.
In particular, by applying a water-repellent coating that prevents water from entering the gap on at least a part of the covering material and the cable, it is possible to more reliably prevent water from entering from the outside of the sensor unit. As described above, since the ingress of moisture from the outside can be surely and easily prevented without using a special seal structure or the like, the structure of the sensor unit can be simplified and the manufacturing cost can be reduced.

  In addition, by covering the sensor device with a cover material having elasticity in particular, even if different thermal expansion occurs between the sensor device and the mold material (cover material) due to the environmental temperature and self-heating of the electronic component, The difference in thermal expansion can be absorbed by the elasticity of the material. Since the liquid is impregnated between the sensor device and the covering material, a difference in thermal expansion can be absorbed by this gap. Even if the gap between the sensor device and the covering material changes based on the difference in thermal expansion, it is possible to prevent moisture from entering the gap.

  The sensor unit of the present invention is electrically connected to the sensor device and a covering material covering the sensor device, the covering material being made of plastic, a thermoplastic elastomer, or a material exhibiting rubber elasticity, and the sensor device. A cable that outputs sensing information from the sensor device, and insulative in a first gap between the cable core of the cable and a cable insulation coating, or a second gap between the covering material and the cable A water repellent coating for preventing moisture from entering the first and second gaps is applied to at least a part of the covering material, the cable insulation coating, and the cable core wire.

According to this configuration, the first gap between the cable core wire and the cable insulation coating or the second gap between the covering material and the cable is impregnated with the insulating liquid, so that the first gap from the outside. It is possible to prevent moisture from entering the first and second gaps. Only by impregnating the first and second gaps with an insulating liquid in advance without using a special seal structure or the like, moisture ingress from outside can be reliably and easily prevented.
In particular, at least a part of the covering material, the cable insulation coating, and the cable core wire is provided with a water-repellent coating that prevents water from entering the first and second gaps, so that moisture can be more reliably entered from the outside of the sensor unit. Can be prevented. In this way, it is possible to reliably and easily prevent moisture from entering from the outside without using a special seal structure or the like, so that the structure of the sensor unit can be simplified and the manufacturing cost can be reduced.

  In addition, by covering the sensor device with a cover material having elasticity in particular, even if different thermal expansion occurs between the sensor device and the mold material (cover material) due to the environmental temperature and self-heating of the electronic component, The difference in thermal expansion can be absorbed by the elasticity of the material. Since the liquid is impregnated between the cable core wire and the cable insulation coating or between the covering material and the cable, the difference in thermal expansion can be absorbed by this gap. Even if the gap impregnated with the liquid changes based on the difference in thermal expansion, it is possible to prevent moisture from entering the gap by the impregnated liquid. Moreover, the gap impregnated with the liquid can prevent water from entering the sensor and the peripheral circuits due to thermal distortion inside the sensor unit due to external temperature changes.

  The sensor unit of the present invention is electrically connected to the sensor device and a covering material covering the sensor device, the covering material being made of plastic, a thermoplastic elastomer, or a material exhibiting rubber elasticity, and the sensor device. A cable for outputting sensing information from the sensor device, a first gap between a cable core of the cable and a cable insulation coating, a second gap between the covering material and the cable, and the sensor device The third gap between the cover and the covering material is impregnated with an insulating liquid, and at least a part of the covering material, the cable insulation coating, and the cable core wire is connected to the first, second, and third gaps. It is characterized by applying a water-repellent coat that prevents moisture from entering.

According to this configuration, the first gap between the cable core wire and the cable insulation coating, the second gap between the covering material and the cable, and the third gap between the sensor device and the covering material have insulating properties. By being impregnated with the liquid, it is possible to prevent moisture from entering the gaps from the outside. By simply impregnating the gap with an insulating liquid without using a special sealing structure or the like, it is possible to reliably and easily prevent moisture from entering from the outside.
In particular, at least a part of the covering material, the cable insulation coating, and the cable core wire is provided with a water-repellent coating that prevents moisture from entering the first, second, and third gaps, so that moisture can enter from the outside of the sensor unit. Can be prevented more reliably. As described above, since the ingress of moisture from the outside can be surely and easily prevented without using a special seal structure or the like, the structure of the sensor unit can be simplified and the manufacturing cost can be reduced. In addition, the thermal expansion difference can be absorbed by the elasticity of the molding material. Even if the gap impregnated with the liquid changes based on the difference in thermal expansion, it is possible to prevent moisture from entering the gap by the impregnated liquid. Moreover, the gap impregnated with the liquid can prevent water from entering the sensor and the peripheral circuits due to thermal distortion inside the sensor unit due to external temperature changes.

In the present invention, the fourth gap between the cable insulation coating and the cable cover of the cable is impregnated with an insulating liquid, and at least one of the covering material, the cable cover, the cable insulation coating, and the cable core wire. It is preferable to apply a water repellent coat to prevent moisture from entering the first, second, third and fourth gaps. It is possible to reliably and easily prevent moisture from entering through the first, second, third and fourth gaps.
In the present invention, the sensor device is preferably a magnetic sensor. In the present invention, the magnetic sensor is preferably composed of a Hall sensor, a magnetoresistive element, a giant magnetoresistive element, or a coil. Further, the magnetic sensor is composed of a plurality of aligned magnetic detection elements, and outputs a predetermined multiplication number based on an internal signal generated by calculating outputs of the plurality of magnetic detection elements. May be generated. By using a sensor having a multiplication function, it is possible to obtain a rotation detection resolution several to several tens of times that of a pattern formed on a magnetic encoder or the like to be detected. The magnetic sensor is preferably configured to be attachable to a wheel bearing device of an automobile. According to this configuration, it is possible to realize an automobile part having performances such as mechanical strength, waterproofness, weather resistance, and chemical resistance.

  In the sensor unit of the present invention, since the liquid between the sensor device and the covering material is impregnated with an insulating liquid, it is possible to prevent moisture from entering the gap from the outside. By simply impregnating the gap with an insulating liquid without using a special sealing structure or the like, it is possible to reliably and easily prevent moisture from entering from the outside.

In particular, by applying a water-repellent coating that prevents water from entering the gap on at least a part of the covering material and the cable, it is possible to more reliably prevent water from entering from the outside of the sensor unit. As described above, since the ingress of moisture from the outside can be surely and easily prevented without using a special seal structure or the like, the structure of the sensor unit can be simplified and the manufacturing cost can be reduced.
Even when different thermal expansion occurs between the sensor device and the molding material (covering material), the thermal expansion difference can be absorbed by the elasticity of the molding material. Even if the gap between the sensor device and the covering material changes based on the thermal expansion difference, it is possible to prevent moisture from entering the gap by the impregnated liquid. Moreover, the gap impregnated with the liquid can prevent water from entering the sensor and the peripheral circuits due to thermal distortion inside the sensor unit due to external temperature changes.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to portions corresponding to the matters described in the preceding forms in each embodiment, and overlapping description may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  The sensor unit according to the present embodiment is applied to, for example, an automobile anti-lock brake system (ABS) sensor. However, the present invention is not necessarily limited to automobiles, and can be applied to various vehicles such as two-wheeled vehicles, railway vehicles, and transport vehicles, and can be attached to various bearings and peripheral members of the bearings.

  FIG. 1 is a sectional view of a sensor unit according to the first embodiment of the present invention. The sensor unit 1 includes a sensor assembly 2 and a molding material 3 (corresponding to a covering material) that covers a main part of the sensor assembly 2. The sensor assembly 2 includes a sensor 4, which is a magnetic sensor, an electrode terminal 5, a cable core wire 6, a cable insulation coating 7, a cable cover 8, a metal fixing bracket (not shown) for positioning these members, and a connector 9. Have The sensor 4 as the sensor device is realized by a Hall sensor, a magnetoresistive element (MR sensor, MR: Magneto Resistance), a giant magnetoresistive element (GMR sensor, GMR: Giant Magneto Resistance), or a magnetic sensor including a coil. .

  One surface portion of the sensor 4 is arranged at a predetermined distance from the magnet body or metal body provided on a rotating member (not shown). The magnet body is, for example, a magnetic encoder magnetized alternately in the circumferential direction. The metal body is, for example, a gear-shaped pulsar ring. An electrical terminal 4a is attached to the base end portion of the sensor 4, and an electrode terminal 5 made of a metal having good electrical conductivity is electrically connected to the electrical terminal 4a by crimping, soldering or other joining methods. ing.

  The cable core wire 6 is electrically connected to the longitudinal end portion of the electrode terminal 5 by crimping, soldering or other joining method, and a cable insulation coating 7 is provided to ensure electrical insulation of the cable core wire 6. Yes. A cable insulation coating 7 is provided on the outside of the cable core wire 6 except for the longitudinal base end and the tip. It is desirable that the cable insulation coating 7 is made of, for example, steel, aluminum, copper, brass, or the like via a gap (annular gap) and can be further plastically deformed. Further, a cable cover 8 is provided on the outside of the cable insulation coating 7 except for one end and the other end in the longitudinal direction. The cable core wire 6, the cable insulation coating 7, and the cable cover 8 correspond to cables.

  The electrode terminal 5 is connected to the longitudinal direction proximal end portion of the cable core wire 6, and the connector 9 is connected to the longitudinal direction distal end portion of the cable core wire 6. The connector 9 includes a contact 9a, a connector case 9b that annularly covers a main part of the contact 9a, and a seal member 9c. The seal member 9c is configured to prevent water from entering the main part of the contact 9a from the cable side. The connector case 9b is opened to one side in the extending direction of the wall portion, and the main part of the contact 9a is exposed to the outside. As a result, the contact 9a and the connected portion (not shown) are detachably connected. The connector case 9b is provided with a partition wall 9ba for partitioning each contact 9a. A seal member 9c is provided on the base end side in the extending direction of the connector case 9b, and the connector case 9b and the seal member 9c are formed in a bottomed cylindrical shape.

  The molding material 3 as the covering material is made of plastic, a thermoplastic elastomer, or a material exhibiting rubber elasticity. In the present embodiment, the molding material 3 covers the sensor 4, the electrode terminal 5, the longitudinal base end portion of the cable core wire 6, the longitudinal end portion of the cable insulation coating 7, and the longitudinal end portion of the cable cover 8. The sensor unit 1 is integrally formed so as to cover the main part of the sensor 4 and the like with the molding material 3.

  For the rubber material of the molding material 3, for example, nitrile rubber and fluororubber are preferable because they are excellent in heat resistance, low temperature characteristics and oil resistance, but other rubber materials may be used. Instead of these rubber materials, thermoplastic elastomers may be used. Of these, vinyl chloride, ester, and amide are particularly preferable because of their excellent heat resistance and oil resistance. In any case, the material for molding the sensor or the like may be any material that exhibits rubber elasticity.

  FIG. 2 is a cross-sectional view of a main part showing a state in which a gap between the sensor device and the covering material is impregnated with an insulating liquid. FIG. 3 is a main portion showing a state in which an insulating liquid is impregnated in the gap between the cable core wire, the cable insulation coating, the cable insulation coating, the cable cover, and the gap between the covering material and the cable. FIG. As shown in FIG. 2, there is a first annular gap δ <b> 1 (corresponding to a third gap) between the molding material 3 and the electric terminal 4 a and the electrode terminal 5 of the sensor 4. There is a second annular gap δ2 between the molding material 3 and the longitudinal base end of the cable core wire 6. Furthermore, there is a third annular gap δ3 between the molding material 3 and one end portion in the longitudinal direction of the cable insulation coating 7, and a fourth annular gap between the molding material 3 and one longitudinal end portion of the cable cover 8. There is δ4 (corresponding to the second gap).

  These annular wall portions δ1, δ2, δ3, and δ4 are impregnated with an insulating liquid LQ (described later).

  A first axial gap is formed between one end in the axial direction of the convex portion 10 forming the second wall 3a2 and the front end in the longitudinal direction of the electrode terminal 5 facing the one end in the axial direction. δy1 exists, and a second axial gap δy2 exists between the other axial end portion of the convex portion 10 and one longitudinal end portion of the cable insulation coating 7 of the molding material 3. A third axial gap between the step portion 11 between the third wall portion 3a3 and the fourth wall portion 3a4 of the molding material 3 and one longitudinal end portion of the cable cover 8 facing the step portion 11 δy3 exists. In the present embodiment, the axial direction (axial direction) is synonymous with the axial direction of the cable, and the radial direction is synonymous with a direction orthogonal to the axial direction. These first to third axial gaps δy1, δy2, and δy3 are impregnated with an insulating liquid LQ.

As shown in FIG. 3, the cover coating gap δa (corresponding to the fourth gap) between the cable cover 8 and the cable insulation coating 7 is impregnated with an insulating liquid LQ. The coated core wire gap δb (corresponding to the first gap) is also impregnated with an insulating liquid LQ. The first to fourth annular wall portions δ1, δ2, δ3, δ4, the first to third axial gaps δy1, δy2, δy3, the cover covering gap δa, and the covered core wire gap δb may be referred to as a gap. Note that reference numeral x <b> 1 shown in FIG. 3 is a part of the cable cover 8.
The liquid LQ to be impregnated in the gaps will be described.
As the liquid LQ, for example, a liquid having excellent insulating properties such as silicon oil and having a low vapor pressure performance in a use environment temperature state (even at a high temperature state of 100 ° C.) can be applied. The liquid LQ may be, for example, a vacuum pump oil having a low vapor pressure performance of 2 × 10 ⁻¹ Pa in use temperature environment such as fluorine oil or hydrocarbon, in addition to silicon oil. That's fine.

  The whole or a part of the sensor unit main body is immersed in the liquid LQ described above, and the liquid LQ is impregnated in a gap or the like. In order to smoothly impregnate the liquid LQ, an oleophilic film fm for reducing the surface tension may be formed in advance on each component of the sensor unit 1. FIG. 4 is a diagram illustrating a state in which a film is formed on the sensor unit component, and FIG. 4A is a cross-sectional view of a main part in which a cover is formed on the cable cover, the cable insulation coating, the cable core wire, and the like. (B) is an expanded sectional view of the principal part.

  That is, the outer periphery of the electric terminal 4a of the sensor 4, the outer periphery of the electrode terminal 5, and the front end in the longitudinal direction are, for example, a parent having a film thickness t1 (the film may be a thin film and simply oleophilic (so that oil can easily enter)). An oily film fm is formed. For example, on the outer peripheral portion of the cable core wire 6 (excluding the connection end portion with the electrode terminal 5), the entire cable insulating coating 7, that is, the outer peripheral portion, inner peripheral portion, one end portion in the longitudinal direction, and the other end portion of the cable insulating coating 7. A lipophilic film fm having a thickness t1 is formed. For example, a lipophilic film fm having a film thickness t1 is formed on the outer peripheral part, inner peripheral part, one end part in the longitudinal direction, and the other end part of the cable cover 8 (the film formation part is the surface of the oil, in particular, at the worst. It suffices if it can be formed on the cable insulation coating 7 where tension is a problem. These coatings fm are formed in advance on each part before assembling the sensor assembly 2. However, the film fm may be formed on each part before assembling the sensor unit main body and after assembling the sensor assembly 2.

  Specifically, such a lipophilic film fm is realized by titanium oxide, various surfactants, or the like. However, the coating material is not limited to these. In the present embodiment, the lipophilic film fm is formed on the electrical terminal 4a of the sensor 4 and the cable, but it is sufficient that the object to be coated is on at least a part of the sensor 4, the molding material 3, and the cable. In the present embodiment, the sensor unit main body may be immersed in the liquid LQ under a reduced pressure environment (1 atm or less, for example, 0.1 atm).

  In this case, the gas inside the sensor unit main body is excluded, and the impregnation of the liquid LQ into the sensor unit is ensured. That is, when the sensor unit main body is immersed in the liquid LQ under a reduced pressure environment, the liquid LQ is surely impregnated into the gap or the like while excluding gas existing in the gap or the like. Therefore, the liquid LQ can be surely filled in the gap or the like inside the sensor unit main body. In other words, since no gas remains in the gap or the like, it is possible to prevent moisture from entering through the gas. In addition, by immersing the sensor unit main body in the liquid LQ under a reduced pressure environment, the liquid LQ can be rapidly impregnated into the sensor unit. Therefore, the work man-hour can be reduced.

In the present embodiment, a water repellent coating hc such as Teflon coating (polytetrafluoroethylene: abbreviated as Teflon “registered trademark”) is applied to an external water inlet as shown in A, B, and C in the figure.
The water repellent coating hc on the moisture ingress port A will be described.
As shown in FIGS. 2 and 4, the water repellent coat hc that prevents moisture from entering the fourth annular gap δ 4 between the molding material 3 and one end in the longitudinal direction of the cable cover 8 is provided on the outer periphery of the cable cover 8. For example, by spray coating. The water repellent coat hc is provided on one end side in the longitudinal direction of the cable cover 8 and in the vicinity of the proximal end side wall portion 3k of the molding material 3 after impregnating the gap L with the liquid LQ. A water repellent coat hc may be applied to at least a part of the base end side wall portion 3k (near the fourth annular gap δ4). Of course, it is also possible to apply the water repellent coating hc to the entire proximal side wall portion 3k. When the water repellent coating hc is applied to the outer periphery of the cable cover 8 and the base end side wall portion 3k of the molding material 3, the water inlet A can be further blocked, and the effect of preventing the water from entering from the water inlet A can be obtained. It can be significantly improved. The water repellent coat hc may be applied to at least a part (near the fourth annular gap δ4) of the base end side wall portion 3k of the molding material 3 without applying the water repellent coat hc to the outer periphery of the cable cover 8.

The water-repellent coat hc on the moisture inlet B will be described.
As shown in FIGS. 1 and 3, a water-repellent coat hc that prevents moisture from entering the cover coating gap δa between the cable insulating coating 7 and the cable cover 8 is sprayed along the outer periphery of the cable insulating coating 7, for example. It is given by application etc. The water repellent coat hc is formed on the other end in the longitudinal direction of the cable insulation coating 7 (facing outward in the radial direction) and the other end in the longitudinal direction of the cable cover 8 after impregnating the gap L with the liquid LQ. It is provided near the section. A water repellent coat hc may be applied to at least a part of the cable cover 8 in the other longitudinal end (near the cover covering gap δa). When the water repellent coating hc is applied to the outer periphery of the cable insulation coating 7 and the other end in the longitudinal direction of the cable cover 8, the moisture inlet B can be further blocked, and the effect of preventing the moisture penetration from the moisture inlet B is prevented. Can be significantly increased. The water repellent coat hc may be applied to the other end in the longitudinal direction of the cable cover 8 without applying the water repellent coat hc to the outer periphery of the cable insulation coating 7.

The water-repellent coating hc on the moisture inlet C will be described.
As shown in FIGS. 1 and 3, a water-repellent coat hc that prevents moisture from entering the coated core gap δb between the cable core 6 and the cable insulation coating 7 extends along the exposed portion of the outer periphery of the cable core 6. For example, it is applied by spray coating. The water repellent coat hc is provided at the other end in the longitudinal direction of the cable core wire 6 and in the vicinity of the other end in the longitudinal direction of the cable insulation coating 7 after the gap L and the like are impregnated with the liquid LQ. A water repellent coating hc may be applied to at least a part of the cable insulation coating 7 in the other longitudinal direction (near the coating core wire gap δb). When the water repellent coating hc is applied to the outer periphery of the cable core 6 and the other end in the longitudinal direction of the cable insulation coating 7, the moisture inlet C can be further blocked, and the effect of preventing moisture penetration from the moisture inlet C is achieved. Can be significantly increased. The water repellent coat hc may be applied to the other end in the longitudinal direction of the cable insulation coating 7 without applying the water repellent coat hc to the outer periphery of the cable core wire 6.

  In this embodiment, the water repellent coat hc is applied to a predetermined location by spray coating, but the water repellent coat hc may be applied to the predetermined location by a method other than spray coating (for example, brush coating or the like). However, the water repellent coating is not necessarily limited to the Teflon coating, and, for example, nylon or the like may be applied to the moisture inlet of the sensor unit main body. Also in this case, the same effect as that of the present embodiment (prevention of moisture ingress from the outside is possible) is achieved.

  According to the sensor unit 1 described above, since the gap or the like is impregnated with the liquid LQ having the insulating property, moisture can be prevented from entering the gap or the like from the outside of the sensor unit. Without using a special seal structure or the like, it is possible to reliably and easily prevent moisture from entering from the outside simply by impregnating the gap L or the like in advance with the above-described liquid LQ having insulating properties. When the sensor unit main body is immersed in the liquid LQ, particularly in a reduced pressure environment, the gas inside the sensor unit main body can be eliminated, and the impregnation of the liquid LQ into the sensor unit can be ensured.

  When the coating fm for reducing the surface tension is formed on each part of the sensor assembly 2, the liquid LQ can be impregnated smoothly and reliably. Therefore, since the time for impregnating the liquid LQ can be shortened, man-hours can be reduced. When the sensor unit main body is immersed in the liquid LQ under a reduced pressure environment, the coating fm can smoothly impregnate the liquid LQ in a gap or the like without extremely increasing the degree of vacuum. Therefore, it is possible to reduce the cost of peripheral equipment for reducing the pressure. When the coating fm is formed over the entire portion of the sensor unit main body that forms the gap or the like, the liquid LQ can be impregnated smoothly and more quickly into the gap or the like. Therefore, it is possible to realize a sensor unit that has high product reliability and can reduce manufacturing costs. In particular, water can be prevented from entering from the portions A, B, and C in the figure.

  In particular, a water-repellent coating hc that prevents water from entering the fourth annular gap δ4 is applied along the outer periphery of the cable cover 8 to prevent water from entering the cover-covered gap δa along the outer periphery of the cable insulation coating 7. A water repellent coat hc is applied. Further, a water repellent coat hc is provided along the exposed portion of the outer periphery of the cable core wire 6 to prevent moisture from entering the coated core wire gap δb. Accordingly, it is possible to more reliably prevent moisture from entering from the outside of the sensor unit. As described above, since the ingress of moisture from the outside can be surely and easily prevented without using a special seal structure or the like, the structure of the sensor unit can be simplified and the manufacturing cost can be reduced. In the present embodiment, as described above, the water repellent coating hc is applied to the outer periphery of the cable cover 8, the cable insulation coating 7, and the cable core wire 6, respectively, but a portion to which the water repellent coating hc is applied is necessary. You may limit according to.

  Even if different thermal expansion occurs between the sensor assembly 2 and the molding material 3 due to the environmental temperature and the self-heating of the electronic parts by covering the main part of the sensor assembly 2 with the molding material 3 having elasticity in particular, the molding is performed. The difference in thermal expansion can be absorbed by the elasticity of the material 3. Between the sensor assembly 2 and the molding material 3, there is a gap or the like for impregnating the liquid LQ, and the gap or the like can absorb a difference in thermal expansion. Even if a gap or the like between the sensor assembly 2 and the molding material 3 changes based on the difference in thermal expansion, it is possible to prevent moisture from entering the gap or the like.

  In the present embodiment, a magnetic sensor is applied to the sensor device, but this sensor device may be any sensor device that supplies electric power or sends an electrical signal output from the outside. As another embodiment of the present invention, at least one of the first to fourth annular wall portions δ1, δ2, δ3, δ4 and the first to third axial gaps δy1, δy2, δy3 is insulated. It may be a sensor unit impregnated with a liquid having a property. In addition, a sensor unit in which at least one of the second to fourth annular wall portions δ2, δ3, δ4, the cover covering gap δa, and the covering core wire gap δb is impregnated may be used. Also in such a sensor unit, it is possible to prevent moisture from entering the gap by the liquid impregnated in the gap. Other effects similar to those of the present embodiment are obtained.

  FIG. 5 is a cross-sectional view showing a state in which the sensor unit according to the embodiment of the present invention is attached to a wheel bearing device of an automobile. In this automobile wheel bearing device, the sensor unit 1 is attached to the wheel bearing device 12 in order to control various controls such as an anti-lock brake system (ABS) and a traction control system (TCS). . That is, the wheel bearing device 12 includes an outer member 13, an inner member 14, a double row rolling element 15, a cage 16, a seal 17, a cover 18, a magnetic encoder 19 (may be pulsar ring), and the sensor unit 1. .

  The outer member 13 is fixed to a vehicle body not shown, and the inner member 14 is attached to the wheel. Between the outer member 13 and the inner member 14, double row rolling elements 15 are interposed by a cage 16 at regular intervals in the circumferential direction to realize a hub bearing. One end of the inner member 14 and the outer member 13 in the axial direction is provided with a contact-type seal 17 such as an oil seal that seals the annular space formed between the inner member 14 and the outer member 13. ing. The magnetic encoder 19 is provided on an inner ring 20 that is a component of the inner member 14.

  A closing cover 18 is provided at one axial end of the outer member 13, and the sensor unit 1 is attached to the cover 18 so as to face the magnetic encoder 19. A sensor unit main body is detachably provided on the cover 18 using bolts, nuts and the like not shown in the state in which at least the sensor portion of the sensor unit 1 is fitted. In the state where the sensor portion is fitted in the cover 18, the annular gap of the cover 18 that may exist between the sensor unit body and the sensor unit main body is tightly sealed by the elasticity of the molding material that covers the sensor portion. .

  Even when the wheel bearing device 12 is installed in a severe environment in which a large temperature change from 100 degrees or more to minus several tens of degrees occurs, the molding material of the sensor unit 1 elastically deforms following the temperature change. . Moreover, even if the sensor unit 1 is deformed, it is possible to prevent the insulative liquid existing between the internal members from entering water or the like from the outside undesirably. Even in such a severe environment, in the sensor unit 1, when different thermal expansion occurs between the sensor assembly and the molding material, the thermal expansion difference can be absorbed by the elasticity of the molding material. Therefore, it is possible to prevent an undesired gap from being generated between the sensor assembly and the molding material, and the waterproofness of the sensor assembly itself can be maintained. Therefore, it is possible to realize a wheel bearing device that satisfies the performance required for automobile parts, such as mechanical strength, waterproofness, weather resistance, and chemical resistance.

  In the present embodiment, the sensor unit 1 is attached to the wheel bearing device, but the sensor unit 1 may be attached to a peripheral member of the wheel bearing device. In the present embodiment, the sensor unit 1 is opposed to the magnetic encoder 19 in the axial direction, but the sensor unit 1 may be opposed to the magnetic encoder 19 in the radial direction. Further, in the present embodiment, for example, a double-row angular contact ball bearing type wheel bearing device for supporting a driven wheel has been described as an example. However, the present invention relates to a wheel bearing device for driving wheel support, a tapered roller, and the like. The present invention can also be applied to a wheel bearing device such as a type. Even in this case, the same effects as in the present embodiment can be obtained.

  6 to 13 are cross-sectional views each showing an example of a wheel bearing equipped with the sensor unit 1 according to the embodiment. First, a configuration common to these examples will be described, and thereafter, different portions of each example will be described individually. The wheel bearing is attached to a vehicle such as an automobile. In this specification, the side closer to the outer side in the vehicle width direction when attached to the vehicle is called the outboard side, This is called the inboard side which is the center side.

These wheel bearings interpose a double-row rolling element 53 between an outer member 51 and an inner member 52 and rotatably support the wheel with respect to the vehicle body. The rotation detection device 1 and a magnetic encoder 19 which is a detected object detected by the sensor unit 1 are provided. The sensor unit 1 has the configuration described with reference to FIG. 1, but the outer shape thereof is not the same as the shape shown in FIG. 1, and is a shape corresponding to the mounting form for each example.
The outer member 51 is a fixed member, and the inner member 52 is a rotating member. The rolling elements 53 of each row are held by the cage 54 for each row, and are formed on the outer circumference of the inner row 52 and the double row rolling surfaces 55 formed on the inner circumference of the outer member 51. Further, it is interposed between the double row rolling surfaces 56. These wheel bearings are of a double row angular contact ball bearing type, and the rolling surfaces 55, 55, 56, 56 of both rows are formed such that the contact angles are back to back. Hereinafter, the wheel bearings in each figure will be described individually.

The example of FIG. 6 is a so-called third generation type, and is an example applied to driving wheel support. The inner member 52 includes two members, a hub wheel 57 and an inner ring 58 fitted to the outer periphery of the inboard side portion of the shaft portion 57a of the hub wheel 57. The rolling surfaces 56 of each row are formed on the outer periphery of 58. The shaft portion 57a of the hub wheel 57 has a center hole 57c through which a stem portion of a constant velocity joint (not shown) is inserted. The inner ring 58 is fitted in a stepped portion formed in the shaft portion 57a of the hub wheel 57, and is fixed to the hub wheel 57 by a crimping portion 57aa provided at the inboard side end of the shaft portion 57a. The hub wheel 57 has a wheel mounting flange 57b on the outer periphery in the vicinity of the end portion on the outboard side, and a wheel and a brake rotor (both not shown) are attached to the wheel mounting flange 57b by a hub bolt 59. The hub bolt 59 is press-fitted into a bolt mounting hole provided in the wheel mounting flange 57b. The outer member 51 is an integral member as a whole, and has a vehicle body mounting flange 51b on the outer periphery. The outer member 51 is attached to a knuckle (not shown) of the suspension device by a knuckle bolt inserted through the bolt hole 60 of the vehicle body attachment flange 51b.
Both ends of the bearing space between the outer member 51 and the inner member 52 are sealed by sealing devices 61 and 62 made of contact seals or the like.

  The magnetic encoder 19 is composed of a ring-shaped multipolar magnet having magnetic poles N and S alternately in the circumferential direction, and is installed in a fitted state on the outer peripheral surface of the inner member 52 between the rolling elements 53 and 53. The magnetic encoder 19 that is a detection object is made of, for example, one in which a multi-pole magnet 19b such as a rubber magnet or a plastic magnet is provided on the outer periphery of a metal core 19a, or a sintered magnet.

  The sensor unit 1 is attached to the outer member 51 by being inserted through a sensor attachment hole 63 that is radially penetrated between both rolling element rows 53, 53, and the tip (portion where the sensor 4 in FIG. 1 is embedded). Is opposed to the magnetic encoder 19 in the radial direction via a magnetic gap. The sensor mounting hole 63 is a through hole having a circular cross-sectional shape, for example. The inner surface of the sensor mounting hole 63 and the sensor unit 1 may be sealed with a contact seal such as an O-ring or an adhesive.

The sensor unit 1 has a shaft-shaped insertion portion 1 a having an inner diameter that substantially fits in the sensor mounting hole 63 and a head portion 1 b that is a non-insertion portion. The head portion 1 b is in contact with the outer peripheral surface of the outer member 51. Arranged. The cable 8A is pulled out from the head 1b. The sensor unit 1 may be protected by covering the head 1b with a cover made of metal or resin.
The cable 8A includes the cable core wire 6, the cable insulation coating 7, and the cable cover 8 shown in FIG. In the example of FIG. 1, the cable is shown in a straight line, but when mounted on the wheel bearing in the example of FIG. 6, the sensor unit 1 bends the cable 8 </ b> A as shown in FIG. 14, for example. In the figure, the schematic cross-sectional shape of the portion constituted by the molding material 3 in FIG.

  According to the wheel bearing of this configuration, the mold material 3 of the sensor unit 1 follows the temperature change even when used in a severe environment where a large temperature change occurs, for example, from several tens of degrees to minus several tens of degrees. And elastically deforms. Moreover, even if the vibration accompanying vehicle travel is added to the wheel bearing device, the molding material 3 of the sensor unit 1 is elastically deformed following the vibration. Therefore, it is possible to prevent water or the like from entering the bearing from undesirably from between the sensor unit 1 and the inner surface of the sensor mounting hole 63 of the outer member 51. Even if the sensor unit 1 is deformed, it is possible to prevent water from the outside from entering undesirably due to the insulating liquid existing between the members inside. Even in such a severe environment, when different thermal expansion occurs between the sensor assembly 2 and the molding material 3 in the sensor unit 1, the thermal expansion difference can be absorbed by the elasticity of the molding material 3. Therefore, it is possible to prevent an undesired gap from being generated between the sensor assembly 2 and the molding material 3, and the waterproofness of the sensor assembly 2 itself can be maintained. Therefore, it is possible to realize a wheel bearing that satisfies the performance required for automobile parts, such as mechanical strength, waterproofness, weather resistance, and chemical resistance.

  FIG. 7 shows the wheel bearing shown in FIG. 6 in which the opposing direction of the sensor unit 1 and the magnetic encoder 19 is the axial direction. The magnetic encoder 19 is provided with a multipolar magnet 19b on a standing plate portion of a cored bar 19a having an L-shaped cross section. In the sensor unit 1, the sensor 4 inside the tip of the sensor unit 1 faces the multipolar magnet 19 b of the magnetic encoder 19 in the axial direction. In addition, it has the same configuration as the wheel bearing shown in FIG. 6, and has the same operations and effects as the wheel bearing shown in FIG.

FIG. 8 shows the wheel bearing shown in FIG. 6 in which the sensor unit 1 is attached to the inboard side end of the outer member 51 via a sensor attachment member 72. The sensor mounting member 72 is a ring-shaped metal plate that fits on the outer peripheral surface of the outer member 51 and contacts the end surface, and has a sensor mounting piece 72a for mounting the sensor unit 1 on a part of the circumferential direction. Yes. The magnetic encoder 19 includes a multi-pole magnet 19b provided on a standing plate portion of a cored bar 19a having an L-shaped cross section, and is fitted to the outer periphery of the inner ring 58. The magnetic encoder 19 also serves as a part of the sealing device 61 on the inboard side. The magnetic encoder 19 and the sensor unit 1 face each other in the axial direction.
In the case of this configuration, the sensor attachment hole 63 in the example of FIG. 6 is not provided in the outer member 51, so there is no problem of water intrusion from the sensor attachment hole 63. Other configurations and effects are the same as in the example of FIG.

FIG. 9 shows an example in which the sealing device 61 for the bearing space on the inboard side is arranged outside the magnetic encoder 19 in the example shown in FIG. That is, a sealing device 61 made of a contact seal or the like is provided between the annular sensor mounting member 72 attached to the outer member 51 and the inner ring 58.
In the case of this configuration, the magnetic encoder 71 is sealed with respect to the external space by the sealing device 61, and foreign matter is prevented from being caught between the magnetic encoder 71 and the sensor unit 1. Other configurations and effects are the same as in the example of FIG.

  FIG. 10 is for the driven wheel in the example shown in FIG. 6, and the hub wheel 57 does not have a center hole and is solid. The end of the outer member 51 on the inboard side extends in the axial direction from the inner member 52, and the end surface opening is covered with a cover 74. The cover 74 is fitted and attached to the inner periphery of the outer member 51 with a flange 74a provided on the outer peripheral edge. The sensor unit 1 is attached to the cover 74 so as to face the magnetic encoder 19. The sensor unit body is detachably provided on the cover 74 using bolts, nuts, etc. (not shown) in a state where at least the sensor part (the part in which the sensor 4 is embedded) 4A of the sensor unit 1 is fitted. In a state where the sensor portion 4A is fitted in the cover 74, the annular gap δm of the cover 74 that can be formed between the sensor unit body and the sensor unit body is tightly sealed by the elasticity of the molding material (elastic member) that covers the sensor portion 4A. It is the composition which becomes. The magnetic encoder 19 is fitted and attached to the outer periphery of the inner ring 58 and faces the sensor unit 1 in the radial direction.

  In the case of this configuration, the application to the driven wheel is limited, but the entire end opening of the outer member 51 is covered by the cover 74, and high sealing performance can be obtained with a simple configuration. Other configurations and effects are the same as those in the example of FIG.

  FIG. 11 shows a configuration in which the magnetic encoder 19 and the sensor unit 1 are opposed to each other in the axial direction in the example shown in FIG. Other configurations and effects are the same as in the example of FIG.

The wheel bearing shown in FIG. 12 is an example of a so-called fourth generation type, and the inner member 52 includes a hub wheel 57A and a constant velocity joint outer ring 81.
The constant velocity joint 80 is formed by forming a plurality of track grooves along the axial direction on the spherical inner surface of the outer ring 81 and the spherical outer surface of the inner ring 82, and interposing the torque transmission balls 84 between the opposed track grooves. . The torque transmission ball 84 is held by the cage 85. The inner ring 82 is fitted to the shaft 86. In the constant velocity joint outer ring 81, a hollow shaft-shaped stem portion 81b protrudes from the outer bottom surface of the cup portion 81a. The stem portion 81b is inserted into the wheel hub 57A of the wheel bearing, and is integrally coupled to the wheel hub 57A by diameter expansion caulking. A rolling surface 56 of each row of the inner member 52 is formed on the hub wheel 57 </ b> A and the constant velocity joint outer ring 81. A bellows-like boot 87 is placed between the opening of the cup portion 81 a of the constant velocity joint outer ring 81 and the outer periphery of the shaft 86.

As in the example of FIG. 6, the sensor unit 1 is attached by inserting the sensor attachment hole 63 through the outer member 51 and inserting the sensor attachment hole 63 into the hole 63. Similar to the example of FIG. 6, the magnetic encoder 19 is attached to the outer periphery of the hub wheel 57 </ b> A in the inner member 52 in a fitted state. The magnetic encoder 19 and the sensor unit 1 are opposed to each other in the radial direction.
Also in this example, the same operation and effect as the example of FIG.

  FIG. 13 shows an example in which the magnetic encoder 19 is opposed to the sensor unit 1 in the axial direction in the example of FIG. Other configurations and effects are the same as in the example of FIG.

    In addition, although the wheel bearing of each said embodiment described the example of a 3rd generation type and a 4th generation type, the wheel bearing with a sensor unit of this invention is provided with a hub and a bearing separately. The present invention can also be applied to generation type and second generation type wheel bearings, and can also be applied to wheel bearings in which the outer member is the rotation side and the inner member is the fixed side. Further, the present invention can be applied not only to the angular ball bearing type but also to a tapered roller type and various other wheel bearings. Furthermore, the detection target detected by the sensor unit 1 is not limited to a magnetic encoder, and may be, for example, a metal gear-shaped pulsar ring.

It is sectional drawing of the sensor unit which concerns on 1st embodiment of this invention. It is sectional drawing of the principal part showing the state which impregnated the liquid which has insulation in the clearance gap between a sensor device and a covering material. A cross-sectional view of the main part showing a state in which an insulating liquid is impregnated in the gap between the cable core wire, the cable insulation cover, the cable insulation cover, the cable cover, and the gap between the covering material and the cable. is there. FIG. 4A is a diagram showing a state in which a coating is formed on the sensor unit component. FIG. 4A is a cross-sectional view of a main part in which a cover is formed on a cable cover, a cable insulation coating, a cable core, and the like, and FIG. It is an expanded sectional view of the principal part. It is sectional drawing showing the state which attached the sensor unit which concerns on the said embodiment of this invention to the wheel bearing apparatus of a motor vehicle. It is sectional drawing showing the state which attached the sensor unit which concerns on embodiment of this invention to the bearing for wheels. It is sectional drawing of the wheel bearing which concerns on other embodiment of this invention. It is sectional drawing of the wheel bearing which concerns on other embodiment of this invention. It is sectional drawing of the wheel bearing which concerns on other embodiment of this invention. It is sectional drawing of the wheel bearing which concerns on other embodiment of this invention. It is sectional drawing of the wheel bearing which concerns on other embodiment of this invention. It is sectional drawing of the wheel bearing which concerns on other embodiment of this invention. It is sectional drawing of the wheel bearing which concerns on other embodiment of this invention. It is a partial abbreviation sectional view of a sensor unit concerning other embodiments of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sensor unit 2 ... Sensor assembly 3 ... Mold material 4 ... Sensor 6 ... Cable core wire 7 ... Cable insulation coating 8 ... Cable cover 12 ... Wheel bearing apparatus LQ ... Liquid hc ... Water repellent coating

Claims (7)

A sensor device;
A covering material for covering the sensor device, wherein the covering material is made of a plastic or thermoplastic elastomer or a material exhibiting rubber elasticity;
A cable that is electrically connected to the sensor device and outputs sensing information from the sensor device,
A gap between the sensor device and the covering material is impregnated with an insulating liquid, and at least a part of the covering material and the cable is provided with a water-repellent coating that prevents moisture from entering the gap. Sensor unit characterized by A sensor device;
A covering material for covering the sensor device, wherein the covering material is made of a plastic or thermoplastic elastomer or a material exhibiting rubber elasticity;
A cable that is electrically connected to the sensor device and outputs sensing information from the sensor device,
A first gap between the cable core of the cable and a cable insulation coating, or a second gap between the covering material and the cable is impregnated with an insulating liquid,
A sensor unit, wherein a water repellent coat for preventing moisture from entering the first and second gaps is applied to at least a part of the covering material, the cable insulation coating, and the cable core wire. A sensor device;
A covering material for covering the sensor device, wherein the covering material is made of a plastic or thermoplastic elastomer or a material exhibiting rubber elasticity;
A cable that is electrically connected to the sensor device and outputs sensing information from the sensor device,
The first gap between the cable core of the cable and the cable insulation coating, the second gap between the covering material and the cable, and the third gap between the sensor device and the covering material have insulating properties. Impregnated with liquid,
A sensor unit, wherein a water repellent coating for preventing moisture from entering the first, second and third gaps is applied to at least a part of the covering material, the cable insulation coating, and the cable core wire. In Claim 2 or Claim 3, it impregnates the liquid which has insulation in the 4th crevice between the cable insulation covering of said cable, and a cable cover,
A sensor comprising: a water repellent coating that prevents moisture from entering the first, second, third, and fourth gaps on at least a part of the covering material, the cable cover, the cable insulation coating, and the cable core wire. unit.   The sensor unit according to claim 1, wherein the sensor device is a magnetic sensor.   6. The sensor unit according to claim 5, wherein the magnetic sensor comprises a Hall sensor, a magnetoresistive element, a giant magnetoresistive element, or a coil.   The sensor unit according to claim 1, wherein the sensor device is configured to be attachable to a wheel bearing device of an automobile.

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