Rotation detection device

A rotation detection device includes a cover member having an opening end, and a sensor body member which has a mounting portion protruding from a mounting-portion protrusion surface and a joint portion positioned around the mounting-portion protrusion surface. The opening end of the cover member is joined to the joint portion of the sensor body member in such a manner that a magnet is housed in the cover member and the mounting-portion protrusion surface is covered by the cover member. A magnetism detection unit is fixedly mounted to the mounting portion and arranged in the magnet. One of the joining surface of the opening end of the cover member and the joining surface of the sensor body member has at least one of a flange-shaped portion and a bent portion. The other of the joining surfaces has a shape corresponding to that of the one thereof.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on a Japanese Patent Application No. 2006-050525 filed on Feb. 27, 2006, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a rotation detection device for detecting a rotation.

BACKGROUND OF THE INVENTION

Generally, with reference toFIG. 11, a rotation detection device is used to detect a rotation of an object such as a vehicle-mounted engine and a vehicle wheel (for wheel velocity detection) and the like, for example, as disclosed in JP-7-260813A (U.S. Pat. No. 5,637,995).

As shown inFIG. 11, the rotation detection device has a sensor chip101(magnetism detection unit) which is arranged to face a rotor RT as the detection object. The sensor chip101has a magnetic resistance element pair1including a magnetic resistance element MRE1and a magnetic resistance element MRE2, and a magnetic resistance element pair2including a magnetic resistance element MRE3and a magnetic resistance element MRE4. The sensor chip101and a processing circuit thereof are arranged in an integrated circuit, and integrally molded in a mold resin102.

Specifically, the sensor chip101is mounted to one end of a lead frame (not shown) in the mold resin102. A feeding terminal T1, an output terminal T2, and a GND (grounding) terminal T3are arranged at other end of the lead frame to be respectively connected to the exterior.

Moreover, a magnet30(bias magnet) is arranged in the vicinity of the sensor chip101to surround the mold resin102. The magnet30applies a bias magnetic field to the magnetic resistance element pairs1and2. The magnet30which has a hollow cylinder shape is provided with a hollow portion31extending in the longitudinal direction of the magnet30. The mold resin102in which the sensor chip101is embraced is inserted in the hollow portion31.

In the practical use of the rotation detection device, the mold resin102in which the sensor chip101is molded, and the magnet30, and the like are accommodated in a suitable case member. The whole of the rotation detection device which has been cased is mounted to an engine or the like, with reference toFIG. 12. The component shownFIG. 12and that shown inFIG. 11which have the same function are same numbered.

As shown inFIG. 12, the mold resin102and the magnet30are integrated with a housing resin120(sensor body member), in such a manner that the mold resin102and the magnet30are accommodated in a cap member40(cover member) which is bottomed. The housing resin120has a flange123used for a connection with an engine body or the like, and a connector portion124which extends from the flange123and functions as a connector for a connection with an electronic control device or the like of the exterior through wirings. The terminals T1-T3are respectively electrically connected with metal terminals100a-100cwhich are integrally arranged in the housing resin120and also used as terminals of the connector portion124.

The rotor RT which faces the sensor chip101can be constructed of a magnetic member having a gear shape, for example. With a rotation of the rotor RT, there is a variation in a magnetic vector which is resultant due to the magnetic field generated by the rotator RT and that generated by the magnet30. The sensor chip101detects the vibration in the magnetic vector as a variation in a resistance value of the magnetic resistance element. Thus, a rotation detection signal can be obtained.

Then, the rotation information of the rotator RT is transferred to the exterior electronic control device (not shown) or the like through the output terminal T2, after passing various process circuits such as a differential amplifier, and a comparator and the like.

However, in this case, the mold resin102where the sensor chip101is embraced, the magnet30and the cap member40are respectively constructed of primary-molding members by injection molding. These primary-molding members are sequentially assembled in the order of the mold resin102, the magnet30and the cap member40, and then set in a suitable mold. Thereafter, the housing resin120is constructed by injection molding to be arranged around the mold resin102, the magnet30and the cap member40. That is, the housing resin120is formed as a secondary-molding member, so that the sensor body member is integrated.

Therefore, the sensor chip101(of rotation detection device) where the magnetic resistance element pairs are arranged is isolated from ambient air of the exterior and protected from pollution and the like, by the mold resin102.

However, when the sensor chip101is molded in the mold resin102, the interior stress is directly applied to the sensor chip101. In the shipment, a suitability is sought by obtaining an appropriate detection output in this state. In this case, the variation in the sensing property due to the time-varying interior stress cannot be ignored.

That is, after the shipment of the rotation detection device to the market and the mounting of the rotation detection device to a vehicle-mounted engine or a general machine, the interior stress which is applied to the sensor chip101has a tendency to be gradually released due to an environment change such as a temperature stress and the like.

Due to the release of the interior stress, an offset variation will be caused because of a magnetostriction effect. Thus, it is difficult to avoid the influence of the offset variation on the sensing property of the rotation detection device.

Recently, it is proposed that the sensor chip101in a bare-chip state is mounted to the sensor body member120and both the sensor chip101and the magnet30are covered by the cap member40. In this case, the cap member40is bottomed, and the opening end of the cap member40is joined to the sensor body member120.

On the other hand, with the miniaturization of various sensor members, the miniaturization of the rotation detection device is desirable. Specially, it is desirable to shorten a distance from a mounting surface (to vehicle-mounted engine or the like) to an end surface of the rotation detection device, that is, a distance UL (i.e., under-neck length) from the mounting surface of the flange123of the rotation detection device (shown inFIG. 12) to the outer surface of the end portion of the cap member40.

Because the detection sensitivity of the rotation detection device greatly depends on the distance between the end surface of the rotation detection device and the detection object (e.g., rotor RT), it is important to set the distance UL which corresponds to a distance of the inner side of the mounting surface of the flange40. Practically, in addition to shorten the distance UL, it is also desirable to provide the rotation detection devices having various sizes corresponding to the machines to which the rotation detection devices are to be mounted.

However, in the case where the sensor chip in the state of the bare chip is mounted to the sensor body member120, the following problems cannot be ignored. That is, though the joining area between the sensor body member120and the cap member40can be maintained in the case where the rotation detection device is provided with the long distance UL, it is difficult to maintain the joining area in the case where the rotation detection device is provided with the short distance UL.

Thus, it is difficult to sufficiently maintain the joining area between the sensor body member120and the cap member40. In the case where the hermeticity of the joining portion cannot be maintained due to the vibration or the like of the object to which the rotation detection device is mounted, the isolation of the sensor chip101(mounted in bare chip state) from the ambient air is deteriorated.

SUMMARY OF THE INVENTION

In view of the above-described disadvantages, it is an object of the present invention to provide a rotation detection device, where a sensor body member and a cover member are substantially joined to each other and a variation over time of a detection property is reduced.

According to the present invention, a rotation detection device has a magnetism detection unit for a detection of a rotation of a detection object which is magnetic, a magnet for applying a magnetic field to the magnetism detection unit, a connection member for electrically connecting the magnetism detection unit with the exterior, a sensor body member which has a mounting portion protruding from a mounting-portion protrusion surface of the sensor body member and a joint portion positioned around the mounting-portion protrusion surface, and a cover member which is bottomed and has an opening at an opening end thereof. The magnet has a substantial cylinder shape. The magnetism detection unit is fixedly mounted to the mounting portion and electrically connected with the connection member. The magnetism detection unit and the mounting portion of the sensor body member are arranged in the magnet. The opening end of the cover member is joined to the joint portion of the sensor body member in such a manner that the magnet is housed in the cover member and the mounting-portion protrusion surface is covered by the cover member. The magnetism detection unit senses a variation of the magnetic field due to a rotation of the detection object so that the rotation of the detection object is detected. The opening end of the cover member has a joining surface which is joined to a joining surface of the joint portion of the sensor body member. One of the joining surfaces has at least one of a flange-shaped portion and a bent portion. The other of the joining surfaces has a shape corresponding to that of the one thereof. The flange-shaped portion circumferentially protrudes outwards from the cover member or the sensor body member.

Accordingly, the sensor chip (magnetism detection unit) can be mounted to the mounting portion of the sensor body member in a bare-chip state, while being isolated from the ambient air by the cover member. Therefore, the variation over time in the sensing property of the rotation detection device can be substantially restricted.

Moreover, one of the joining surface of the opening end of the cover member and that of the joint portion of the sensor body member has at least one of the flange-shaped portion and the bent-shaped portion. The other of the joining surfaces has the shape corresponding to that of the one thereof. Thus, the joining surface of the joint portion and that of the opening end of the cover member can be provided with a lager joining area per unit length in the direction of a distance of the inner side of the mounting surface (i.e., distance UL with reference toFIG. 12), that is, in the direction perpendicular to the chip-mounting-portion protrusion surface of the sensor body member. Therefore, even when the distance (distance UL) of the inner side of the mounting surface in the rotation detection device is short, the adequate joining area between the sensor body member and the cover member can be readily maintained. Thus, the sensor body member and the cover member can be firmly joined to each other irrespective of the distance UL of the inner side of the mounting surface. Accordingly, the isolation of the sensor chip from the ambient air of the exterior by the cover member can be further improved.

DETAILED DESCRIPTION OF THE EXAMPLED EMBODIMENTS

First Embodiment

A rotation detection device according to a first embodiment of the present invention will be described with reference toFIGS. 1-6. With reference toFIG. 1, the rotation detection device can be suitably used to detect a rotation state of a detection object, for example, a crank angle sensor of a vehicle-mounted engine.

As shown inFIGS. 1 and 2, the rotation detection device has a magnet30(bias magnet) and a sensor chip10(magnetism detection unit) which is constructed of a bare chip. The magnet30and the sensor chip10are substantially closed in a housing which includes a sensor body member20and a cover member40(e.g., cap member), to be protected from ambient air of the exterior. The sensor body member20can be constructed of a non-magnetic material, for example, a resin such as PPS (polyphenylene sulphide).

In this case, the sensor chip10can be provided with magnetic resistance element pairs1and2, each of which has two magnetic resistance elements. The sensor chip10can be integrated-circuit constructed together with a processing circuit.

A flange23is arranged at a side wall of the sensor body member20, and can be fastened to an engine body and the like. Moreover, a connector portion24which is connected with an electronic control device and the like of the exterior is arranged at a part of the sensor body member20which extends from the flange23.

The sensor body member20includes a mounting portion21(chip mounting portion) having a substantial plate shape, a joint portion25, and a guide portion26which is arranged between an end surface22(i.e., mounting-portion protrusion surface) of the sensor body member20and the joint portion25to guide the mounting of the cover member40to the sensor body member20.

The mounting-portion protrusion surface22(chip-mounting-portion protrusion surface) is positioned at one end of the sensor body member20, to construct a lead-through surface of the chip mounting portion21. That is, the chip mounting portion21protrudes outwards from the chip-mounting-portion protrusion surface22, into the cover member40. The joint portion25is continuous with the outer periphery of the guide portion26.

As shown inFIGS. 1 and 2, the sensor chip10is electrically connected with connection members, which respectively have a feeding terminal T1, an output terminal T2and a GND (grounding) terminal T3to electrically connect the sensor chip10with the exterior. The connection member can be made of an electrical conductive material (e.g., metal) and double as a lead frame electrically connected with the sensor chip10. The connection member can have a stick shape and bent in the sensor body member20.

In this case, one end of the connection member is used as the terminal T1, T2or T3arranged at the connector portion24. The other end of the connection member constructs a connection portion Tc for connecting with the sensor chip10. The connection members are integrally molded in the sensor body member20to be mounted thereto. The sensor chip10is electrically connected with the connection portion Tc of the connection member through a bonding wire W.

With reference toFIG. 2, the magnet30can have a substantial cylinder shape. For example, the magnet30is provided with a hollow portion31, which can have a shape (e.g., substantially quadrilateral shape) corresponding to that of the chip mounting portion21. The sensor chip10and the chip mounting portion21of the sensor body member20are inserted in the hollow portion31to be covered by the magnet30.

The magnet30applies a bias magnetic field to the magnetic resistance element pairs1and2which are installed in the sensor chip10. In the case where the detection object is a magnetic member such as a rotor RT (with reference toFIG. 11), a magnetic vector resultant due to the detection object and the bias magnet30will vary with the rotation of the detection object. The variation of the magnetic vector is sensed as a resistance value variation of the magnetic resistance element pair1,2. In this case, the magnetic field variation which is caused by a rotation of the detection object with respect to the magnet30is sensed, so that the rotation state of the detection object is detected.

The cover member40has a substantially cylinder shape and is bottomed. An opening end41and a bottom of the cover member40are respectively positioned at two axial ends of the cover member40. The opening end41where the cover member40has an opening can construct a flange (brim) portion of the cover member40. The joint portion25is joined to the opening end41of the cover member40.

The cover member40is made of a non-magnetic material (e.g., resin such as PPS) and has a lower percentage of carbon (that is, has a higher laser transmittance) than the resin material constructing the sensor body member20.

The inner surface of the cover member40is engaged with the guide portion26and the opening end41is joined to the joint portion25, to block the chip-mounting-portion protrusion surface22of the sensor body member20. Thus, the sensor chip10, the chip mounting portion21and the magnet30are protected from the ambient air of the exterior.

According to the rotation detection device described in this embodiment, the joint portion25of the sensor body member20is joined to the opening end41of the cover member40, so that the sensor body member20is integrated with the cover member40. In this case, the joint portion25has a joining surface which is joined to a joining surface of the opening end41of the cover member40. The joining surface of the joint portion25and that of the opening end41which contact each other can be provided with a taper shape with respect to a direction perpendicular to the chip-mounting-portion protrusion surface22. That is, the opening end41of the cover member40is diameter-enlarged to have a flange shape so as to cover the joint portion25, corresponding to the taper shape of the joining surface.

In this case, the joint portion25can be irradiated by laser through the opening end41of the cover member40from the exterior, so that the joint portion25is molten to be joined (that is, laser welded) to the opening end41. Thus, the rotation detection device can be integrated. Moreover, the contact area between the sensor body member20and the cover member40can be maintained, even when a distance UL (i.e., distance of inner side of mounting surface) between the mounting surface of the flange23and the outer surface of the bottom of the cover member40is shortened.

Next, the manufacture method of the rotation detection device will be described with reference toFIGS. 3A,3B and4.

With reference toFIG. 3A, at first, the sensor body member20which includes the chip mounting portion21, the joint portion25and the guide portion26is beforehand constructed by injection-molding (using a suitable mold) or the like, while the end portions (of side where terminals T1, T2and T3are arranged) of the connection members are molded in the sensor body member20.

Then, the sensor chip10is mounted to the chip mounting portion21of the sensor body member20, by an adhesive or the like. In this case, after the sensor chip10is fixed to the chip mounting portion21, the sensor chip10is electrically connected with the connection portion Tc of the connection member through the bonding wire W.

On the other hand, the magnet30can be constructed by injection-molding (using a suitable mold) or the like as a separate component from the sensor body member20, and magnetized. Similarly, the cover member40can be constructed by injection-molding (using a suitable mole) or the like, as a separate component from the sensor body member20and the magnet30.

Thereafter, with reference toFIG. 3B, after the magnet30is mounted to the sensor body member20to cover the sensor chip10and the chip mounting portion21of the sensor body member20, the cover member40is fitted to the magnet30in such a manner that an inner surface46of the cover member40is engaged with the guide portion26of the sensor body member20.

Then, as shown inFIG. 4, the laser L from the exterior is provided to irradiate the joining surface of the opening end41of the cover member40and that of the joint portion25of the sensor body member20which have been assembled.

As described above, the material (e.g., resin material) of the cover member40has the higher laser transmittance than the material (e.g., resin material) of the sensor body member20, so that the joint portion25is earlier molten to integrate the sensor body member20with the cover member40. Because the stance of the cover member40can be properly maintained with respect to the sensor body member20by the engagement between the inner surface46of the cover member40and the guide portion26of the sensor body20, the welding accuracy can be improved.

Next, the effects of the rotation detection device will be described.

According to this embodiment, the joining surface of the joint portion25and that of the opening end41which contact each other are provided with the taper shape in the direction perpendicular to the chip-mounting-portion protrusion surface22of the sensor body member20. Therefore, the joining surface of the joint portion25and that of the opening end41can be provided with a lager joining area per unit length in the direction of the distance UL, that is, the direction perpendicular to the chip-mounting-portion protrusion surface22of the sensor body member20.

Thus, even when the distance UL of the inner side of the mounting surface is short, the adequate joining area between the sensor body member20and the cover member40can be readily maintained. The sensor body member20and the cover member40can be firmly joined to each other irrespective of the distance UL of the inner side of the mounting surface. Accordingly, the isolation of the sensor chip10from the ambient air of the exterior by the cover member40can be improved.

Moreover, according to this embodiment, the sensor chip10in the state of the bare chip is mounted to the chip mounting portion21of the sensor body member20. Therefore, the mounting position of the sensor chip10at the chip mounting portion21can be positioned with a high accuracy. Moreover, the occurrence of inner stress in the molding and the influence on the detection property (i.e., sensing property) due to the release of the inner stress can be reduced, as compared with a conventional rotation detection device where the sensor chip10is resin-molded. That is, according to this embodiment, the variation over time in the sensing property of the rotation detection device can be reduced.

According to this embodiment, the joint portion25of the sensor body member20is provided with the guide portion26, which extends from the joint portion25and is engaged with the inner surface46of the cover member40to guide the mounting of the cover member40with respect to the sensor body member20. Thus, the cover member40can be readily mounted to the sensor body member20. Moreover, the stance of the cover member40with respect to the sensor body member20can be suitably maintained in the joining process.

Moreover, according to this embodiment, the joint portion25of the sensor body member20and the opening end41of the cover member40are joined to each other by the laser-welding. Thus, the joining of the opening end41of the cover member40with respect to the joint portion25of the sensor body member20can be performed stably, and the joining strength can be improved. Particularly, the guide portion26extends from the joint portion25of the sensor body member20, so that the stability in the joining (welding) process can be improved.

In this case, the material of the cover member40has the lower carbon percentage than the material of the sensor body member20. Thus, the laser transmittance of the resin material of the cover member40is higher than that of the sensor body member20, so that the laser welding can be performed with a heightened stability and an improved efficiency.

As described above with reference toFIG. 1, the joining surface of the joint portion25of the sensor body member20and that of the opening end41of the cover member40have the taper shape. In this case, the taper-shaped contact surface can be substantially linear in the cross section thereof taken along the axis direction of the cover member40.

Alternatively, according to a first modification of this embodiment, as shown inFIG. 5, the joining surface of the joint portion25and that of the opening end41have a curvature in a tapering direction of the taper shape. That is, the taper-shaped joining surface of the joint portion25is concave (as shown inFIG. 5which is cross sectional view taken along axis direction of cover member40), when being viewed from the side of the cover member40. Correspondingly, the taper-shaped joining surface of the opening end41is convex (as shown inFIG. 5which is cross sectional view taken along axis direction of cover member40), when being viewed from the side of the sensor body member20.

More alternatively, according to a second modification of this embodiment, as shown inFIG. 6, the joining surface of the joint portion25and that of the opening end41are provided with the taper shape which has a curvature in a tapering direction of the taper shape. The taper-shaped joining surface of the joint portion25is convex (as shown inFIG. 6which is cross sectional view taken along axis direction of cover member40), when being viewed from the side of the cover member40. Correspondingly, the taper-shaped joining surface of the opening end41is concave (as shown inFIG. 6which is cross sectional view taken along axis direction of cover member40), when being viewed from the side of the sensor body member20.

According to each of the first modification and the second modification, the joining surface of the joint portion25of the sensor body member20and that of the opening end41of the cover member40have a further lager joining area per unit length in the direction of the distance UL (shown inFIG. 1) of the inner side of the mounting surface.

Second Embodiment

Next, a second embodiment of the present invention will be described with reference toFIG. 7. In this case, the shapes of the joining portion25of the sensor body member20and the opening end41of the cover member40which are joined to each other are different from those described in the above-described first embodiment. That is, the shapes of the joining surfaces are different from those of the first embodiment. The effect similar to the first embodiment can be provided by the second embodiment.

In the first embodiment, the joining surface of the joint portion25of the sensor body member20and that of the opening end41of the cover member40which are integrated with each other have the taper shape with respect to the direction perpendicular to the chip-mounting-portion protrusion surface22of the sensor body member20.

According to the second embodiment, as shown inFIG. 7, the joining surface of the joint portion25is provided with a rugged portion which has at least one projection and at least one depression. Correspondingly, the joining surface of the opening end41of the cover member40is provided with a rugged portion which has at least one projection and at least one depression to correspond to the rugged portion of the joining surface of the joint portion25. In this case, the opening end41of the cover member40can be arranged to substantially linearly extend from the cylindrical portion of the cover member40, or have the taper shape with respect to the cylindrical portion. Thus, the joint portion25of the sensor body member20is shaped corresponding to the opening end41of the cover member40.

According to the second embodiment, the joining surfaces of the joint portion25and the opening end41can be integrally engaged with each other with a larger contact area. In this embodiment, the guide portion26can be also omitted.

According to the second embodiment, the stance of the cover member40with respect to the sensor body member20can be suitably maintained. Moreover, the stability in the joining process (by laser welding or the like) of the joining surfaces of the joint portion25and the opening end41can be further improved.

In the second embodiment, each of the joining surface of the joint portion25and that of the opening end41is provided with the at least one projection and at least one depression so that the joining area between the joining surfaces can be enlarged.

When the cover member40is mounted to the sensor body member20, the projection and depression of the joining surface of the opening end41and those of the joining surface of the joint portion25can be also used similarly to a screwing construction between a male screw and a female screw.

About the rotation detection device, what has not described in the second embodiment is the same with the first embodiment.

Third Embodiment

According to a third embodiment of the present invention with reference toFIG. 8, the shapes of the joining portion25of the sensor body member20and the opening end41of the cover member40which contact each other are different from those described in the above-described embodiments. That is, the shapes of the joining surfaces are different from those of the above-described embodiments.

As shown inFIG. 8, the joining surface of the joint portion25of the sensor body member20is provided with a stepped shape. Correspondingly, the joining surface of the opening end41of the cover member40has a stepped shape which is integrally engaged with the stepped shape of the joining surface of the joint portion25. The joining surface of the joint portion25and that of the opening end41are joined to each other.

About the rotation detection device, what has not described in the third embodiment is the same with the first embodiment. The effect similar to the first embodiment can be provided by the third embodiment.

Fourth Embodiment

According to a fourth embodiment of the present invention with reference toFIG. 9, the shapes of the joining portion25of the sensor body member20and the opening end41of the cover member40which contact each other are different from those described in the above-described embodiments. That is, the shapes of the joining surfaces are different from those of the above-described embodiments.

According to the fourth embodiment, as shown inFIG. 9, a wedge-shaped groove is arranged at the joining surface of the joint portion25of the sensor body member20. Correspondingly, the joining surface of the opening end41of the cover member40has a wedge-shaped protrusion which is integrally engaged with (inserted in) the groove of the joining surface of the joint portion25. In this case, the opening end41of the cover member40can be arranged to substantially linearly extend from the cylindrical portion of the cover member40, or have the taper shape with respect to the cylindrical portion. Thus, the joint portion25of the sensor body member20is shaped corresponding to the opening end41of the cover member40.

Alternatively, the substantially wedge-shaped groove can be also provided at the joining surface of the opening end41of the cover member40, and the substantially wedge-shaped protrusion can be also provided at the joining surface of the joint portion25of the sensor body member20.

About the rotation detection device, what has not described in the fourth embodiment is the same with the first embodiment. The effect similar to the first embodiment can be provided by the fourth embodiment.

Fifth Embodiment

According to a fifth embodiment of the present invention with reference toFIG. 10, the shapes of the joining portion25of the sensor body member20and the opening end41of the cover member40which contact each other are different from those described in the above-described embodiments. That is, the shapes of the joining surfaces are different from those of the above-described embodiments.

As shown inFIG. 10, the joint portion25of the sensor body member20has a ring shape which is substantially parallel with the chip-mounting-portion protrusion surface22of the sensor body member20. In this case, the guide portion26(which is engaged with inner surface46of cover member40) of the sensor body member20can be substantially perpendicular to the chip-mounting-portion protrusion surface22and the joint portion25.

Correspondingly, the opening end41of the cover member40has a ring shape which is substantially perpendicular to the inner surface46of the cover member40. That is, the opening end41constructs the brim (flange) of the cover member40, which is substantially perpendicular to the cylindrical portion of the cover member40. In this case, the ring-shaped joining surface of the joint portion25is integrally engaged with the ring-shaped joining surface of the opening end41.

About the rotation detection device, what has not described in the fifth embodiment is the same with the first embodiment. The effect similar to the first embodiment can be provided by the fifth embodiment.

OTHER EMBODIMENT

In the above-described embodiments, the sensor body member20and the cover member40can be constructed of the PPS resin. In this case, the material of the cover member40has the higher laser transmittance than the sensor body member20by the adjustment of the carbon percentage in the material. However, each of the sensor body member20and the cover member40can be constructed of other resin. Moreover, the laser transmittance can be adjusted by other method. For example, the laser transmittance can be adjusted, by altering a pigment and/or an addition material in the PPS resin. Alternatively, the laser transmittance can be adjusted, by modifying the composition of the resin. More alternatively, the cover member40can be constructed of a transparent resin which has an excellent laser transmittance.

In the above-described embodiment, the sensor body member20and the cover member40can be integrated with each other by the laser welding, for example. Alternatively, the sensor body member20and the cover member40can be also integrated with each other by other welding method such as a vibration welding, a hot plate welding and the like. More alternatively, the sensor body member20and the cover member40can be also integrated with each other by bonding through an adhesive or the like. In the case where the sensor body member20and the cover member40are integrated with each other by the joining method other than the welding, the sensor body member20and the cover member40can be constructed of any resin material which is suitable for the joining method.

In the above-described embodiments, the guide portion26(of sensor body member20) which is engaged with the inner surface46of the cover member40extends from the joining portion25of the sensor body member20to guide the mounting of the cover member40to the sensor body member20. However, including the second embodiment, the guide portion26can be also omitted if the stance of the cover member40with respect to the sensor body member20can be maintained. In this case, a jig unit or the like can be used to maintain the suitable stance of the cover member40.

Moreover, the shapes of the joining surfaces of the joining portion25of the sensor body member20and the opening end41of the cover member40can be also set in other manner, without being limited to the shapes in the above-described embodiments. Furthermore, each of the joint portion25and the opening end41can be also provided with the shape which is a combination of the shape characteristics respectively defined in the different above-described embodiments.

Furthermore, in the above-described embodiments, the joint portion25of the sensor body member20is covered by the opening end41of the cover member40. However, the position relation between the joint portion25of the sensor body member20and the opening end41of the cover member40can be also contrary to that. That is, the opening end41of the cover member40can be also covered by the joint portion25of the sensor body member20. The joint portion25can protrude from the outer periphery of the chip-mounting-portion protrusion surface22of the sensor body member20, toward the protruding direction of the chip mounting portion21.

In this case, the inner surface of the joint portion25contacts the outer surface of the opening end41of the cover member40. The sensor body member20and the cover member40can be integrated with each other by the laser welding or the like, and constructed of the resin material, for example. In this case, it is desirable that the resin material of the sensor body member20has a higher laser transmittance than the resin material of the cover member40. Moreover, for example, the joining surface of the sensor body member20and the joining surface of the cover member40which are joined to each other are shaped similarly to what is described above, so that the joining area per unit length in the direction of the distance UL of the inner side of the mounting surface is enlarged.

In the above-described embodiments, the sensor chip10is constructed of a single chip in which the processing circuit and the like are integrated. However, for example, the processing circuit can be also integrated in a chip other than the sensor chip10.

Such changes and modifications are to be understood as being in the scope of the present invention as defined by the appended claims.