JPH09288020A - Magnetostrictive torque detector and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of a crack at a resin case or core member. SOLUTION: A plurality of grooves 16C, mounting grooves 16D are formed on the cylindrical piece 1 of a core member 15, and a plurality of grooves 19C are formed at the collar 19B of a winding part 19 for constituting a coil bobbin 18. After the members 15 and bobbin 18 are assembled, when an inner casing 24 is molded as a resin case at the outer peripheral side, melted resin material flows to the grooves 16C, 16D of the piece 16 into the piece 16, and is rapidly and effectively charged between the piece 16 and the part 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetostrictive torque detector suitable for use in detecting torque generated on an output shaft of an automobile engine and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 14 shows a magnetostrictive torque detecting device according to the prior art. That is, the magnetostrictive shaft 2 is rotatably provided in the cylindrical casing 1 through the bearings 3 and 3. In the casing 1, a pair of core members 4 and 4 are provided so as to surround the outer peripheral side of the magnetostrictive shaft 2, and each core member 4 includes two core pieces 4.
It is formed by abutting A and 4A. Further, coil bobbins 5 and 5 are provided on the inner peripheral side of each core member 4,
Each coil bobbin 5 is provided with exciting and detecting coils 6 and 6 for detecting the torque acting on the magnetostrictive shaft 2 as an electric signal. Further, in the casing 1, a resin case 7 formed by integrally surrounding each core member 4, each coil bobbin 5, and the excitation and detection coil 6 by resin molding is provided.

As described above, the conventional magnetostrictive torque detecting device has a structure in which the resin case 7 is formed by integrally surrounding the core members 4, the coil bobbins 5, the excitation and detection coils 6 by resin molding. Therefore, there is an advantage that it is possible to prevent the core members 4 and the coil bobbins 5 from being displaced due to external vibration or shock.

The magnetostrictive torque detecting device according to the prior art described above is manufactured by the following procedure. That is, first, the excitation and detection coil 6 is wound around each coil bobbin 5. Then, after applying an adhesive for temporary fixing to the abutting surface of each core piece 4A of the core member 4, each core piece 4A is attached from both sides of the coil bobbin 5, and each core piece 4A is impacted so as to wrap the coil bobbin 5. To combine. Next, each core member 4 and each coil bobbin 5 are inserted into a molding die for molding the resin case 7, and a molten resin material is injected into the molding die. As a result, each core member 4 and each coil bobbin 5 are molded with a resin material to form a resin case 7. And the resin case 7
After being inserted into the casing 1, the magnetostrictive shaft 2, each bearing 3 and the like are attached to the casing 1 to complete the magnetostrictive torque detecting device.

[0005]

By the way, in the above-mentioned prior art, there is a problem that cracks 8 are generated in the resin case 7 or the core member 4 as shown in FIG. The main cause of cracks 8 in the resin case 7 or the core member 4 is poor flowability of the molten resin material injected into the mold when the resin case 7 is formed during manufacturing of the magnetostrictive torque detection device. Especially.

That is, since the flowability of the molten resin material is not good, the molten resin material becomes thermally non-uniform in the mold.
Weld lines may occur in the resin case 7.
This weld line causes cracks 8. Also, if the molten resin material becomes thermally non-uniform in the mold,
It is conceivable that the injection pressure of the molten resin material does not act uniformly on the core member 4 and stress concentration is likely to occur, which may cause cracks 8.

On the other hand, in the manufacture of the magnetostrictive torque detecting device, when the core member 4 is mounted on the outer peripheral side of the coil bobbin 5, an adhesive is applied to the abutting surface of each core piece 4A, and each core piece is applied by this adhesive. 4A is temporarily fixed. At this time,
When the thickness of the adhesive applied to the abutting surface of each core piece 4A becomes non-uniform, and when the core pieces 4A abut, the adhesive sticks out to the outer peripheral side of each core piece 4A and hardens as it is. There is. In this way, when each core member 4 and each coil bobbin 5 assembled with the adhesive protruding are set in the molding die and the resin case 7 is formed, stress concentrates on the portion of the core member 4 where the adhesive protrudes. However, there is a problem that cracks 8 are likely to occur in the core member 4.

Further, since the thickness of the adhesive applied to the abutting surface of each core piece 4A is not uniform, the core pieces 4A may not be abutted in parallel with each other and may be displaced. in this way,
Each core member 4 and each coil bobbin 5 assembled with each core piece 4A displaced from each other are mounted on a molding die,
When the resin case 7 is formed, stress concentrates on the stepped portion and the gap formed by the displacement of the core pieces 4A,
There is a problem that cracks 8 are likely to occur in the core member 4.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention provides a magnetostrictive torque detecting device capable of preventing cracks from occurring in a resin case or a core member, and a manufacturing method thereof. It is an object.

[0010]

In order to solve the above-mentioned problems, a feature of the invention described in claim 1 is that a molten resin material for forming a resin case is provided in the tubular portion of each core member. In order to flow into the inner peripheral side of each core member, a plurality of inflow ports are formed in the circumferential direction for communicating between the outer peripheral side and the inner peripheral side of the core member.

With the above construction, when the resin case is manufactured,
After assembling each core member, coil bobbin, excitation and detection coil, this assembly is set in a molding die and a molten resin material is injected into the molding die. At this time, the molten resin material injected into the molding die flows between the inner wall of the molding die and the outer peripheral side of each core member, and through a plurality of inflow ports formed in the tubular portion of each core member. It flows into the inner peripheral side of the core member and flows between the inner peripheral wall of the core member and the outer peripheral side of the coil bobbin.

As a result, until the molten resin material is filled between the inner peripheral wall of the core member and the outer peripheral side of the coil bobbin after the resin injection is started, the outer peripheral side of each core member is well filled with the molten resin material. It comes to flow. This suppresses stress concentration during molding of the resin case and eliminates thermal nonuniformity of the resin material over the entire outer circumference of each core member.

According to a second aspect of the present invention, a groove is formed in the flange portion of the coil bobbin for filling the molten resin material flowing into the inner peripheral side of the core member between the coil bobbin and the core member. is there.

With the above structure, when the resin case is manufactured, the assembly of the core members, the coil bobbins, the exciting and detecting coils is set in the molding die, and the molten resin material is injected into the molding die. Then, the molten resin material injected into the molding die flows between the inner wall of the molding die and the outer peripheral side of each core member, and through the plurality of inflow ports formed in the tubular portion of each core member, It flows into the inner peripheral side of the core member and flows between the inner peripheral wall of the core member and the outer peripheral side of the coil bobbin. At this time, the molten resin material smoothly flows between the inner peripheral wall of the core member and the outer peripheral side of the coil bobbin via the groove formed in the flange portion of the coil bobbin, and the inner peripheral wall of the core member and the outer peripheral side of the coil bobbin. It goes all the way between.

As a result, the molten resin material is quickly and surely filled between the inner peripheral wall of the core member and the outer peripheral side of the coil bobbin to suppress stress concentration during molding of the resin case and increase the temperature of the core member. Be uniform.

According to a third aspect of the present invention, an annular step portion extending in the circumferential direction is formed on the outer peripheral side of the collar portion of the coil bobbin.

With the above structure, when the resin case is manufactured, the assembly of the core members, the coil bobbins, the exciting and detecting coils is set in the molding die, and the molten resin material is injected into the molding die. Then, the molten resin material injected into the molding die flows between the inner wall of the molding die and the outer peripheral side of each core member, and through the plurality of inflow ports formed in the tubular portion of each core member, It flows into the inner peripheral side of the core member and flows between the inner peripheral wall of the core member and the outer peripheral side of the coil bobbin.

Here, the outer diameter dimension of the flange portion of the coil bobbin and the inner diameter dimension of the core member are substantially equal, and when the coil bobbin is mounted in the core member, the outer peripheral surface of the collar portion contacts the inner peripheral wall of the core member. However, since the annular step portion is formed on the outer peripheral side of the collar portion of the coil bobbin, the collar portion has a partially small diameter. Therefore, the outer peripheral side of the flange portion and the inner peripheral wall of the core member are partially separated from each other, and an annular space is formed between the outer peripheral side of the flange portion and the inner peripheral wall of the core member.

As a result, the molten resin material flowing between the inner peripheral wall of the core member and the outer peripheral side of the coil bobbin flows into the annular space and flows in the annular space in the circumferential direction. This suppresses stress concentration during molding of the resin case and makes the temperature rise of the core member uniform over the entire circumference.

According to a fourth aspect of the present invention, a pair of tubular core members are provided at least in the axial direction so as to surround the outer circumferential side of the magnetostrictive shaft, and the tubular core members are provided on the inner circumferential side of each core member. A coil bobbin consisting of a shaft portion formed on the shaft portion and a collar portion formed on both axial ends of the shaft portion, and on the shaft portion of each coil bobbin for detecting the torque acting on the magnetostrictive shaft as an electric signal. Magnetostrictive torque composed of an excitation and detection coil formed by winding a winding, and a tubular resin case integrally formed by molding each core member, each coil bobbin, and excitation and detection coil with a resin material. In the detection device, each coil bobbin around which an excitation and detection coil is wound, an assembly step of assembling each core member, and each coil bobbin assembled in the assembly step, A temporary fixing step of temporarily fixing the core member with a heat-resistant temporary fixing tape, each coil bobbin temporarily fixed in the temporary fixing step, and a resin case is formed by molding the outside of each core member with a resin material. The configuration includes a molding step.

With the above construction, in the temporary fixing step, each coil bobbin and each core member are temporarily fixed using the temporary fixing tape so that the coil bobbins and the core members are not displaced when the resin case is molded. As a result, each coil bobbin and each core member can be fixed in a state where they are positioned at predetermined positions, and this temporary fixing work is easy and the workability is good.

[0022]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

Here, FIGS. 1 to 8 show examples in which the magnetostrictive torque detection device according to the first embodiment of the present invention is used for torque detection of an automobile engine.

In FIG. 1, reference numeral 11 denotes a cylindrical outer casing which constitutes an outer shell of the magnetostrictive torque detecting device according to the present embodiment. The outer casing 11 has a cylindrical portion 11A and an axial direction of the cylindrical portion 11A. From annular projections 11B and 11B located on both sides and projecting radially inward, and bearing housings 11C and 11C located on both axially outer sides of the annular projections 11B and housing bearings 12 and 12, respectively. It is configured.
The outer casing 11 is made of a resin material or a metal material.

Reference numeral 13 denotes a magnetostrictive shaft rotatably provided on the outer casing 11 via bearings 12, 12.
The magnetostrictive shaft 13 forms a part of a propeller shaft, an output shaft, a drive shaft, etc., and is formed in a columnar shape from a magnetostrictive material such as chrome molybdenum steel. Further, a large number of slits 14, 14, ... Are formed on the outer peripheral side of the magnetostrictive shaft 13 around the middle of the magnetostrictive shaft 13 over the entire circumference thereof.

Reference numerals 15 and 15 denote a pair of core members provided so as to surround the outer peripheral side of the magnetostrictive shaft 13,
Each core member 15 is made of a soft magnetic material such as ferrite, and is composed of a tubular core piece 16 and an annular core piece 17 described later.

As shown in FIG. 2, the tubular core piece 16 comprises a tubular portion 16A and an annular plate portion 16B located on one axial side of the tubular portion 16A and projecting radially inward. . In addition, the distal end side of the cylindrical portion 16A is circumferentially 90
Grooves 16C are formed at three locations separated from each other,
A mounting groove 16D having a width dimension larger than that of the groove 16C is formed in the upper portion on the tip side of the cylindrical portion 16A. And each groove 1
6C, the mounting groove 16D, as shown in FIG. 6 or 7,
When forming an inner casing 24, which will be described later, the core member 15 is communicated between the outer peripheral side and the inner peripheral side and serves as an inlet for allowing the molten resin material to flow into the inner peripheral side of the core member 15. Further, the mounting groove 16D is mounted on the connecting portion 21 of the coil bobbin 18, which will be described later, as shown in FIG.

On the other hand, the annular core piece 17 is a flat plate having an annular outer shape, and a fitting groove 17A which fits into a connecting portion 21 of a coil bobbin 18 described later is formed on the outer peripheral side of the annular core piece 17. .

Reference numerals 18 and 18 denote a pair of coil bobbins provided on the inner peripheral side of each core member 15. Each coil bobbin 18 has a winding portion 19 as shown in FIG. 3 or 4.
It is composed of an annular spacer 20 provided at a predetermined distance from the winding portion 19 in parallel and coaxial with the winding portion 19, and a connecting portion 21 connecting the annular spacer 20 and the winding portion 19. .

The winding portion 19 is a cylindrical shaft portion 1.
9A, and collar portions 19B, 19B formed so as to project radially outward from both axial sides of the shaft portion 19A. Here, the outer diameter dimension of each of the collar portions 19B and the inner diameter dimension of the tubular core piece 16 are substantially equal, and the winding portion 19 is mounted in the tubular core piece 16 as shown in FIG. Then, the outer peripheral surface of each flange 19B is in contact with the inner peripheral wall of the tubular core piece 16. However, since the outer diameter dimension of the shaft portion 19A is smaller than the outer diameter dimension of each collar portion 19B, the coil 23 to be described later is
Even in the wound state, the outer peripheral side of the shaft portion 19A and the tubular core piece 1
An annular gap is formed between the inner peripheral wall 6 and the inner peripheral wall. Then, when the inner casing 24 is formed, the gap is filled with the molten resin material through each groove 16C and the mounting groove 16D of the tubular core piece 16.

Further, among the collar portions 19B, the collar portion 19B located on the left side in FIG. 3 is provided with grooves 19C at four positions spaced by 90 degrees in the circumferential direction. On the other hand, FIG.
The collar portion 19B located on the right side of the inside includes the collar portion 1 on the left side.
Three grooves 19C are formed at positions corresponding to 9B, and the upper portion of the collar portion 19B is connected to the connecting portion 21. As shown in FIG. 7, each of the grooves 19C serves as a passage for pouring the molten resin material between the tubular core piece 16 and the winding portion 19 when forming the inner casing 24 described later.

Further, as shown in FIG. 5, when the coil bobbin 18 is assembled in each core member 15, the position of each groove 19C formed in the winding portion 19 of the coil bobbin 18 and the core member 15 are The positions of the grooves 16C and the mounting groove 16D formed on the tubular core piece 16 are aligned with each other.

Further, of the collar portion 19B of the winding portion 19,
An annular step portion 19D extending in the circumferential direction is formed on the outer peripheral side of the left flange portion 19B in FIG. Here, as described above, the outer peripheral surface of the collar portion 19B is in contact with the inner peripheral wall of the tubular core piece 16. However, since the annular step portion 19D is formed on the outer peripheral side of the collar portion 19B, the diameter of the collar portion 19B is partially reduced. Therefore, an annular space 19E is formed between the outer peripheral side of the collar portion 19B and the inner peripheral wall of the tubular core piece 16. As a result, as shown in FIG. 7, when the molten resin material is poured between the cylindrical core piece 16 and the winding portion 19 so as to form the inner casing 24 described later, the molten resin material causes the annular space to flow. It flows into 19E.

On the other hand, the annular spacer 20 is, as shown in FIG. 5, the annular spacer 20 of the counterpart coil bobbin 18.
The coil bobbins 18 are mutually positioned by abutting with each other. Further, the annular spacer 20 and the winding portion 19 are connected by a connecting portion 21, and a gap having a predetermined interval is formed between the annular spacer 20 and the winding portion 19. An annular core piece 17 is inserted into this gap as shown in FIG. Further, the connecting portion 21
Electrode terminals 22 and 22 are provided on the upper surface of the.

Reference numerals 23 and 23 denote winding portions 1 of the coil bobbin 18.
9 shows a coil as an exciting and detecting coil formed by winding a winding around the outer peripheral surface of 9, and one end of the winding of each coil 23,
The other end is connected to each electrode terminal 22.

Reference numeral 24 denotes an inner casing as a resin case provided on the inner peripheral side of the outer casing 11, and the inner casing 24 is provided so as to surround the outer peripheral side of the magnetostrictive shaft 13, and each core member 15 and each The coil bobbin 18 and the coils 23 are integrally formed by molding with a resin material.

Reference numerals 25, 25, ... Represent a cylindrical conductive member made of a metal material, and 26 is a connector connected to each conductive member 25. The coils 23 are connected to the external detection circuit via the conductive members 25 and the connector 26.

The magnetostrictive torque detecting device according to the present embodiment has the above-mentioned structure. When an alternating current is applied to each coil 23 from the oscillator of the detecting circuit, each coil 2
The magnetic flux generated from 3 forms a magnetic circuit from each core member 15 to the magnetostrictive shaft 13. When torque acts on the magnetostrictive shaft 13, the coils 23
Since the inductance changes due to each slit 14, a detection signal corresponding to the torque acting on the magnetostrictive shaft 13 can be obtained from the detection circuit including each coil 23.

Next, a method of manufacturing the magnetostrictive torque detecting device according to this embodiment will be described. First, in the coil winding step, a coil is wound around each coil bobbin 18 to form a coil 23.
And the end of the winding is connected to each electrode terminal 22.

Then, in the assembling process, as shown by the arrow A in FIG. 5, the annular spacers 20 of the coil bobbins 18 are abutted against each other. Further, as shown by arrow B, the annular core piece 17 is inserted between the winding portion 19 of each coil bobbin 18 and the annular spacer 20, and both left and right sides of each coil bobbin 18 are shown by arrow C. From each tubular core piece 16
Is inserted. As a result, the annular plate portion 16B of each tubular core piece 16, each annular core piece 17, and each coil bobbin 18 are positioned parallel and coaxial with each other.

Next, in the temporary fixing step, as shown in FIG. 6, temporary fixing tapes 27, 27, ... Are attached to several places on the outer peripheral surface of each core member 15, and each core member 15 and each coil bobbin 18 is attached. Are mutually positioned and temporarily fixed so as to be fixed. Here, each of the temporary fixing tapes 27
Is a heat-insulating single-sided adhesive tape that can withstand the high temperature of the molten resin material when forming the inner casing 24.

As described above, the temporary fixing work is simplified by using the temporary fixing tapes 27 for the temporary fixing of the core members 15 and the coil bobbins 18, and the annular plate portion 16B of each tubular core piece 16 is used. The respective members can be fixed in a state where the respective annular core pieces 17 and the respective coil bobbins 18 are positioned parallel to each other and coaxially with each other.

Next, in the molding step, the core members 15 and the coil bobbins 18 temporarily fixed by the temporary fixing tapes 27 are mounted on a molding die for molding the inner casing 24, and the molten resin is placed in the molding die. Each core member 1 by injecting material
5. The inner casing 24 is formed by molding the coil bobbins 18 and the like with a resin material.

Here, the molten resin material is injected at the same time from the upper side and the lower side of each core member 15, as shown by the arrow in FIG. Then, the molten resin material injected into the mold is
As shown by an arrow in FIG. 6 or 7, while flowing so as to surround the outer peripheral side of each core member 15, each groove 16C formed in each cylindrical core piece 16 and from each mounting groove 16D to each cylindrical core piece It flows into 16. At this time, the groove 1 is formed in each tubular core piece 16.
6C and mounting groove 16D are formed at four places in total,
It smoothly flows into the tubular core piece 16 through each of the grooves 16C and the mounting groove 16D. Then, after the injection of the molten resin material is started, until the molten resin material is completely filled between the inner peripheral wall of the tubular core piece 16 and the outer peripheral side of the winding portion 19, The flow continues on the outer peripheral side of each core member 15. As a result, the molten resin material can smoothly flow without staying on the outer peripheral side of each core member 15,
It is possible to prevent stress concentration during molding of the inner casing 24 and to make the temperature of the molten resin material uniform.

Further, the molten resin material flowing into each tubular core piece 16 from each groove 16C and each mounting groove 16D of each tubular core piece 16 is, as shown by the arrow in FIG. And the respective winding portions 19 flow over the entire circumference. At this time, since each groove 19C is formed in the collar portion 19B of each winding portion 19, the molten resin material smoothly passes through each groove 19C, so that each tubular core piece 16 and each winding portion 19 are smoothly formed. And each coil 23 wound around each winding portion 19 and flowing between
The outer peripheral side of is surrounded all around.

Further, the molten resin material flowing between each tubular core piece 16 and each winding portion 19 is the groove 19C of the collar portion 19B.
And flows into the annular space 19E through the
It goes all around in 9E.

By forming the grooves 19C and the annular stepped portion 19D in each of the collar portions 19B in this manner, the molten resin material is filled between the cylindrical core pieces 16 and the winding portions 19 quickly and reliably. It is possible to suppress the stress concentration at the time of molding the inner casing 24, and at the same time, each core member 1
The temperature rise of 5 can be made uniform. As a result, the inner casing 24 can be formed as shown in FIG.

Next, when the outer casing 11 is made of a resin material, in the outer casing molding step, each electrode terminal 2 protruding from the connecting portion 21 of the coil bobbin 18 is formed.
After inserting the conductive members 25 into the inner casing 2, the inner casing 2 in which the core members 15 and the coil bobbins 18 are integrally housed
4 is attached to a molding die for molding the outer casing 11, and the outer casing 11 is molded by resin molding.

The magnetostrictive shaft 13 is inserted into the bearing housing portions 11C and 11C of the outer casing 11 after the bearings 12 and 12 are inserted into the outer casing 11.

Thus, according to this embodiment, each groove 16C and the mounting groove 16D are formed in the tubular core piece 16 of each core member 15, and when the inner casing 24 is formed, the molten resin material is applied to each groove 16C. , The cylindrical core piece 1 through the mounting groove 16D
By allowing the molten resin material to flow into the inside 6, the flowability of the molten resin material can be improved, and the molten resin material can flow quickly and reliably over the entire outer circumference of each core member 15. This can prevent stress concentration during molding of the inner casing 24 and prevent thermal nonuniformity of the molten resin material.

Therefore, according to this embodiment, it is possible to prevent the weld line from being formed in the inner casing 24 and prevent the inner casing 24 from being cracked.

In particular, as shown in FIG. 7, when the molten resin material is injected simultaneously from the upper side and the lower side of each core member 15, in the prior art, a weld line is easily formed on the lateral side of the inner casing 24. I was worried. However, in this embodiment, since the grooves 16C and 16C are formed on both lateral sides of the tubular core piece 16, the molten resin material does not stay on the lateral side of the tubular core piece 16 and a weld line is generated. Can be reliably prevented.

Further, according to the present embodiment, the groove 19C is formed in the collar portion 19B of the winding portion 19 constituting each coil bobbin 18 at a plurality of positions, so that when the inner casing 24 is formed, the molten resin material is formed into a cylindrical shape. -Shaped core piece 16 and each winding part 1
The molten resin material can be quickly and surely filled between the tubular core piece 16 and each winding portion 19 over the entire circumference so that the molten resin material can flow smoothly between the winding core portion 9 and the winding portion 9.

Therefore, when molding the inner casing 24, it is possible to prevent stress concentration from occurring in a part of the core member 15, and to uniformly increase the temperature of the core member 15.
It is possible to prevent the core member 15 from being cracked.

Further, according to this embodiment, the collar portion 1 is formed by forming the annular step portion 19D on the collar portion 19B of the winding portion 19.
By forming the annular space 19E between the outer peripheral side of 9B and the inner peripheral wall of the tubular core piece 16, the molten resin material surely advances to the inner depth side of the tubular core piece 16 as shown in FIG. The molten resin material flows in the circumferential direction inside the stepped portion 19D, and even on the inner rear side of the tubular core piece 16, the molten resin material is surely distributed over the entire inner circumferential side of the tubular core piece 16. This also
It is possible to make the temperature rise of the core member 15 uniform and prevent the core member 15 from cracking.

Further, according to the present embodiment, since each core member 15 and each coil bobbin 18 are temporarily fixed with each temporary fixing tape 27 before the inner casing 24 is molded, each core member 15, Each of the coil bobbins 18 can be temporarily fixed so as to maintain the state in which they are positioned parallel to each other. As a result, it is possible to prevent the injection pressure during molding of the inner casing 24 from acting non-uniformly and to prevent stress concentration.
4. It is possible to prevent the core member 15 from cracking.

Further, each core member 15 and each coil bobbin 1
Since each temporary fixing tape 27 is used for the temporary fixing with 8, the adhesive does not stick out and the adhesive is not different from the case where the adhesive is used for temporary fixing. Therefore, when molding the inner casing 24, it is possible to eliminate the conventional drawback that has been caused when stress concentration occurs in a portion where the adhesive protrudes, and it is possible to prevent the inner casing 24 and the core member 15 from being cracked. it can.

Furthermore, since each temporary fixing tape 27 is used for temporarily fixing each core member 15 and each coil bobbin 18, the temporary fixing work can be simplified and the workability can be improved.

Next, a second embodiment of the present invention will be described with reference to FIGS. 9 and 10. The characteristic feature of this embodiment is that the molten resin material flows into the core member when the resin case is formed. A large number of inflow ports for making the core member formed are formed in the cylindrical portion of the core member, and a large number of grooves for filling the molten resin material between the coil bobbin and the core member are formed in the flange portion of the coil bobbin.

That is, in the figure, 31 indicates a core member according to the present embodiment, and the core member 31 is formed of a soft magnetic material such as ferrite, similar to the core members 15 according to the first embodiment. The tubular core piece 32 is composed of the tubular portion 32A and the annular plate portion 32B, and the annular core piece 33 having the fitting groove 33A.

However, on the tip side of the tubular portion of the tubular core piece 32 that constitutes the core member 31 according to this embodiment, grooves 32C are formed at 11 locations at equal intervals in the circumferential direction, and In the upper part on the tip side of the core piece 32, a mounting groove 32D having a width dimension larger than that of the groove 32C is formed.
Different from each core member 15 according to the embodiment. When the inner casing 24 is formed, the grooves 32 </ b> C and the mounting grooves 32 </ b> D allow the outer peripheral side and the inner peripheral side of the core member 15 to communicate with each other and the molten resin material to the inner peripheral side of the core member 31. It serves as an inlet for inflow.

Reference numeral 34 represents a coil bobbin according to this embodiment, and the coil bobbin 34 is similar to each coil bobbin 18 according to the first embodiment, and the shaft portion 35A and the collar portion 35 are substantially the same.
B and 35B, an annular spacer 36 that is spaced apart from the winding portion 35 by a predetermined distance and is provided in parallel and coaxially with the winding portion 35, and the annular spacer 36 and the winding portion 3
5, a connecting portion 37 that connects with 5 and has electrode terminals 38, 38
It is composed of

However, the coil bobbin 34 according to the present embodiment.
Of the collar portion 35B of the winding portion 35 that constitutes the above, the collar portion 35B located on the left side in FIG. 10 is provided with grooves 35C, 35C, ... There is. On the other hand, the collar portion 35B located on the right side in FIG.
Grooves 35C, 35 are formed at positions corresponding to the left collar portion 35B.
.. are formed at 11 positions, and the upper portion of the collar portion 35B is connected to the connecting portion 37. And each of these grooves 35C
Serves as a passage for pouring the molten resin material between the cylindrical core piece 32 and the winding portion 35 when forming the inner casing 24.

Here, when the coil bobbin 34 is assembled in each core member 31, the position of each groove 35C formed in the winding portion 35 of the coil bobbin 34 and the core member 3
Each of the grooves 32C formed in the tubular core piece 32 of No. 1 and the mounting groove 3
The 2D position is adapted to match each other. Further, the collar portion 35B of the winding portion 35 according to the present embodiment has the first
An annular step portion 35D is formed similarly to each coil bobbin 18 according to the embodiment.

The magnetostrictive torque detecting device having such a structure also has substantially the same effect as that of the first embodiment.

It should be noted that in each of the embodiments described above, FIG.
As shown in FIG. 1, the tubular core piece 16 of the core member 15 (31)
Although the quadrangular grooves 16C (32C) are formed in (32), the present invention is not limited to this, and the groove shape is semicircular like the groove 41A of the tubular core piece 41 shown in FIG. May be.

Further, like the groove 51A of the tubular core piece 51 shown in FIG. 12 or 13, the groove shape is semicircular, and the outer edge of the groove 51A is expanded on the outer peripheral side of the tubular core piece 51. Then, the tapered portion 51B may be formed. This allows
When the inner casing 24 is molded, the molten resin material smoothly flows into the tubular core piece 51.

Further, in each of the above embodiments, the two-coil type magnetostrictive torque detecting device has been described as an example. However, the present invention is not limited to this, and may be applied to a four-coil type magnetostrictive torque detecting device. Good.

Furthermore, in each of the above-mentioned embodiments, the case where the invention is used for detecting the torque of an automobile engine is taken as an example. It can also be used for torque detection.

[0070]

As described in detail above, according to the invention described in claim 1, a molten resin material for forming a resin case is provided on the inner peripheral side of each core member in the tubular portion of each core member. Since a plurality of inlets are formed in the circumferential direction for communicating between the outer peripheral side and the inner peripheral side of the core member in order to make the resin member flow, the stress concentration during molding of the resin case can be suppressed and the heat of the resin material can be suppressed. The non-uniformity can be eliminated. Therefore, it is possible to prevent weld lines and cracks from occurring in the resin case.

According to the second aspect of the invention, the flange portion of the coil bobbin is formed with a groove for filling the molten resin material flowing into the inner peripheral side of the core member between the coil bobbin and the core member. Therefore, the molten resin material can be quickly and reliably filled between the inner peripheral wall of the core member and the outer peripheral side of the coil bobbin. Therefore, it is possible to prevent stress concentration at the time of molding the resin case, make it possible to uniformly increase the temperature of the core member, and prevent the core member from cracking.

According to the third aspect of the invention, since the annular step portion extending in the circumferential direction is formed on the outer peripheral side of the collar portion of the coil bobbin, stress concentration during molding of the resin case can be suppressed and the temperature rise of the core member can be suppressed. Can be made uniform and cracks can be prevented from occurring in the core member.

According to the fourth aspect of the present invention, each coil bobbin and each core member are temporarily fixed with a temporary tape having heat resistance so that each coil bobbin and each core member are positioned parallel to each other. It can be temporarily fixed so as to maintain the fixed state. Accordingly, it is possible to prevent the resin injection pressure during molding of the resin case from acting non-uniformly and to prevent stress concentration, and to prevent the resin case, the core member, and the like from being cracked.

Further, since the temporary fixing tape is used for temporary fixing to each coil bobbin and each core member, unlike the case of temporarily fixing using the adhesive, there is no protrusion of the adhesive or defective adhesion. Therefore, it is possible to eliminate the defect that stress concentrates on the protruding portion of the adhesive in the mold of the resin case, and it is possible to prevent cracks from occurring in the resin case, the core member, and the like. Furthermore, since the temporary fixing tape is used for temporarily fixing each coil bobbin and each core member, the temporary fixing work can be facilitated and the workability can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a magnetostrictive torque detection device according to a first embodiment.

FIG. 2 is an exploded perspective view showing a core member in FIG.

3 is a perspective view showing a coil bobbin in FIG. 1. FIG.

FIG. 4 is a vertical sectional view showing a coil bobbin in FIG.

FIG. 5 is an exploded perspective view showing an assembled state of each core member and each coil bobbin.

FIG. 6 is a perspective view showing an assembled state of each core member and each coil bobbin.

FIG. 7 is a vertical cross-sectional view showing an assembled state of each core member and each coil bobbin.

FIG. 8 is a vertical cross-sectional view showing a state in which an inner casing is formed on the outer peripheral side of each core member and each coil bobbin.

FIG. 9 is an exploded perspective view showing a core member of a magnetostrictive torque detection device according to a second embodiment.

FIG. 10 is a perspective view showing a coil bobbin of the magnetostrictive torque detection device according to the second embodiment.

FIG. 11 is an enlarged perspective view of an essential part showing a semicircular groove formed in a tubular core piece.

FIG. 12 is an enlarged perspective view of an essential part showing a semicircular groove formed in a tubular core piece and a taper portion.

FIG. 13 is a side view of the groove and taper portion of the tubular core piece in FIG. 12 seen from the side.

FIG. 14 is a vertical cross-sectional view showing a magnetostrictive torque detection device according to a conventional technique.

FIG. 15 is a perspective view showing a state where cracks are generated in the resin case and the core member.

[Explanation of symbols]

 13 Magnetostrictive shaft 15 Core member 16 Cylindrical core piece 16A Cylindrical portion 16C Groove (inlet) 16D Mounting groove (inlet) 18 Coil bobbin 19 Winding portion 19A Shaft portion 19B Collar portion 19C groove 19D Annular step portion 23 Coil 24 Inner casing (Resin case)

Claims (4)

[Claims] 1. A tubular core member provided at least in the axial direction so as to surround the outer peripheral side of the magnetostrictive shaft,
A coil bobbin provided on the inner peripheral side of each core member and formed of a tubular shaft portion and a collar portion formed on each axial end of the shaft portion, and a torque acting on the magnetostrictive shaft. In order to detect as an electric signal, an exciting and detecting coil formed by winding a winding around the shaft of each coil bobbin, and the core member, the coil bobbins, and the exciting and detecting coil are molded by a resin material to be integrated. In a magnetostrictive torque detection device including a tubular resin case formed as described above, in the tubular portion of each core member, a molten resin material for forming the resin case is flown into the inner peripheral side of each core member. In order to make it possible, a magnetostrictive torque detecting device is characterized in that a plurality of inlets are formed in the circumferential direction for communicating the outer peripheral side and the inner peripheral side of the core member. 2. The flange of the coil bobbin is formed with a groove for filling the molten resin material flowing into the inner peripheral side of the core member between the coil bobbin and the core member. The magnetostrictive torque detection device described. 3. The magnetostrictive torque detecting device according to claim 1, wherein an annular step portion extending in the circumferential direction is formed on the outer peripheral side of the flange portion of the coil bobbin. 4. A tubular core member provided at least in a pair in the axial direction so as to surround the outer peripheral side of the magnetostrictive shaft,
A coil bobbin provided on the inner peripheral side of each core member, the coil bobbin including a cylindrical shaft portion and a collar portion formed on each axial end of the shaft portion, and torque acting on the magnetostrictive shaft. In order to detect as an electric signal, an excitation and detection coil formed by winding a coil around the shaft of each coil bobbin, and the core member, each coil bobbin, excitation and detection coil are molded with a resin material to be integrated. In a magnetostrictive torque detection device including a tubular resin case formed by the above, an assembly process of assembling each coil bobbin around which an excitation and detection coil is wound and each core member, and Coil bobbin, temporary fixing step of temporarily fixing each core member with a temporary fixing tape having heat resistance, and each coil bobbin and each core member temporarily fixed in the temporary fixing step Method for producing a magnetostrictive torque detecting apparatus and a molding step of forming a resin case by molding the outer resin material.