JPH085477A - Magnetic distortion type torque sensor - Google Patents

Abstract

PURPOSE:To improve the vibration resistance and the water resistance by forming a casing of resin mold. CONSTITUTION:A casing 30 is formed of an inside casing 31, which is formed of the low-pressure resin mold at a degree, which does not break a core member 33, and an outside casing 32, which is formed of the high-pressure resin mold outside of the inside casing 31, from the periphery of each core member 33 and each coil bobbin 36. With this structure, each core member 33 and each coil bobbin 36 can be accurately positioned in relation to a magnetic distorting shaft 3, and strongly fixed so as to prevent the generation of displacement due to the vibration to be applied from outside. Each electrode terminal 42, each connecting member 43, each connector 45 or the like are provided so as to electrically connect a coil 41, which is wound around a coil part 37 of each coil bobbin 36, to an external detecting circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetostrictive torque sensor suitable for use in detecting torque generated in an output shaft of an automobile engine, for example.

[0002]

2. Description of the Related Art First, FIG. 13 shows a case where a two-coil type magnetostrictive torque sensor is used as a conventional magnetostrictive torque sensor for detecting torque of an automobile engine.

In the figure, reference numeral 1 denotes a metal casing fixed to a vehicle body (not shown) of an automobile. The metal casing 1 is made of metal and formed into a tubular shape. The casing 7, the core member 8, the coil bobbin 9 and the like are housed. In addition, an annular protrusion 1A that projects inward in the radial direction is formed on one end side in the axial direction of the metal casing 1, and an annular recess 1B is formed on the other end side in the axial direction. , C-ring 2 is attached. Then, the annular casing 1A and the C ring 2 are used to form the resin casing 7, the core member 8, and the coil bobbin 9.
Etc. are positioned in the metal casing 1. Further, a mounting portion 1D having a wiring connection hole 1C at one location is provided at an axially intermediate portion of the metal casing 1.

Reference numeral 3 is rotatably supported in the metal casing 1 via bearings 4 and 4, and is, for example, a propeller shaft,
A magnetostrictive shaft forming a part of an output shaft, a drive shaft, etc. is shown, and the magnetostrictive shaft 3 is formed in a columnar shape from a magnetostrictive material such as chrome molybdenum steel. Further, the magnetostrictive shaft 3 is located near the middle in the axial direction, and the outer peripheral surface of the magnetostrictive shaft 3 has slits 5, 5, ... On one side and slits 6, 6, ... On the other side. The slits 5 on one side have an inclination of 45 °, and the slits 6 on the other side are 45 in the opposite direction to the slits 5. Have a slope of.

Reference numeral 7 denotes a resin casing housed in the metal casing 1 and provided on the outer peripheral side of the magnetostrictive shaft 3. The resin casing 7 surrounds each core member 8 with a resin mold from the outside. Thus, the core members 8, the coil bobbins 9, etc. are integrally housed. As a result, the positional relationship between the core members 8 and the like is accurately determined, positional deviation is prevented, and durability is improved.

Reference numerals 8 and 8 denote a pair of core members located on the outer peripheral side of the slits 5 and 6 and provided in the resin casing 7. The core members 8 are made of a soft magnetic material such as ferrite. Two core pieces 8A, 8 formed in a stepped cylindrical shape at the bottom
It is formed by abutting A. Further, a minute air gap is formed between each core member 8 and the magnetostrictive shaft 3.

Reference numerals 9 and 9 represent a pair of coil bobbins provided on the inner peripheral side of the core members 8 and 8, respectively.
Is made of a resin material in a cylindrical shape, the middle part thereof is a shaft part, and both end sides of the shaft part are flange parts. A coil is wound around the outer circumference of each coil bobbin 9 to form coils 10, 10 as exciting and detecting coils. Further, each end of each coil 10 is connected to each of electrode terminals 11, 11, ...

In the wiring connection holes 1C of the metal casing 1, reference numerals 11 and 11 are fixed to the flanges on one side of the coil bobbins 9 at the base end side and penetrate the core member 8 and the resin casing 7 at the tip side. Shows a plurality of electrode terminals (only two are shown) slightly protruding, and the respective end portions of the coils 10 and 10 are connected to the respective electrode terminals 11.

Further, on the tip side of each of the electrode terminals 11,
A plurality of lead wires 12 are externally connected via the wiring connection holes 1C of the metal casing 1. Each lead wire 12 is connected to a detection circuit (not shown) provided outside, so that each coil 10 and the detection circuit are electrically connected. The detection circuit is composed of an oscillator, a differential amplifier circuit, a bridge circuit and the like, and the bridge circuit is composed of the coils 10 and a plurality of fixed resistors.

Reference numeral 13 denotes a cap attached to the mounting portion 1D of the metal casing 1. The cap 13 closes the wiring connection hole 1C and seals the wiring connection hole 1C. Further, the cap 13 is provided with a small-diameter hole for inserting each lead wire. Between the small-diameter hole and each lead wire, the wiring connecting hole 1C is sealed, so that a rubber is used. Packing 14 such as is provided.

The magnetostrictive torque sensor according to the prior art has the above-mentioned structure, and its operation will be described below. When an AC voltage is applied to each coil 10 from the oscillator of the detection circuit, a magnetic circuit is formed from each core member 8 to the magnetostrictive shaft 3 by the magnetic flux generated from each coil. When torque acts on the magnetostrictive shaft 3,
Since the inductance of each of the coils 10 is changed by the slits 5 and 6, a detection signal corresponding to the torque acting on the magnetostrictive shaft 3 can be obtained from a detection circuit (bridge circuit) including the coils 10. it can.

[0012]

In the prior art described above, the resin casing 7 in which the core members 8, the coil bobbins 9 and the like are integrated is housed in the metal casing 1 and fixed by the C ring 2. I am trying.

However, in such a structure, the resin casing 7 may be displaced in the metal casing 1 due to the influence of engine vibration and traveling vibration of the automobile.
As a result, the positions of the slits 5 and 6 of the magnetostrictive shaft 3 are displaced from the positions of the core members 8 and the coil bobbins 9, and the accuracy of torque detection is significantly reduced.

Further, in the above-mentioned prior art, a slight gap may be formed between the inner peripheral surface of the metal casing 1 and the outer peripheral surface of the resin casing 7, and water or the like from the outside may be formed in this gap. It may infiltrate. Then, when water or the like enters this gap and reaches the inside of the wiring connection hole 1C formed in the axial middle of the metal casing 1, each electrode terminal 11 in the wiring connection hole 1C To make a short
There is a problem that the torque cannot be detected accurately.

As another prior art, Japanese Patent Application No. 4-3
In the magnetostrictive torque sensor described in No. 41578, as shown in FIG. 14, each core member 8 and each coil bobbin 9 and the like are housed in a single resin casing 21. The member 8 is surrounded by a resin mold from the outside, and each core member 8 and each coil bobbin 9 are positioned and integrated, and
The casing 21 also functions as an outer shell of the magnetostrictive torque sensor according to the other conventional technique.

In such another conventional technique, since the casing 21 is a single resin case, water and the like will not enter the wiring connection hole 21C unlike the above-mentioned conventional technique. In the manufacturing process of the magnetostrictive torque sensor, when each core member 8, each coil bobbin 9, etc. is inserted into a mold and the casing 21 is molded from the outside of each core member 8 by resin molding, a mold at the time of resin filling A crack may occur in the core member 8 due to the pressure, which increases the number of defective products and deteriorates the yield.

In order to prevent the core member 8 from cracking, the resin filling pressure at the time of molding the casing 21 may be set to a low pressure. In this case, the casing 21 is soft. And the casing 21
The durability as the outer shell of the magnetostrictive torque sensor cannot be ensured. Therefore, the resin filling pressure of the casing 21 must be set to a high pressure to some extent.

The present invention has been made in view of the above-mentioned problems of the prior art, and improves the vibration resistance and water resistance to improve the accuracy of torque detection and to improve the yield of the magnetostrictive torque sensor. An object of the present invention is to provide a magnetostrictive torque sensor that can be improved.

[0019]

In order to solve the above-mentioned problems, the feature of the configuration adopted by the invention of claim 1 is that the casing is an inner casing formed by low pressure resin molding on the outer peripheral side of each core member. And an outer casing formed by a high-pressure resin mold on the outer peripheral side of the inner casing.

According to a second aspect of the present invention, the coil bobbin has one side fixed to the coil bobbin, the winding ends of the excitation and detection coils being connected thereto, and the other side extending outward in the radial direction. A plurality of electrode terminals exposed on the outer peripheral surface of the inner casing are provided. One side of the inner casing is fitted and fixed to each of the electrode terminals, and the other side extends radially outward and is exposed on the outer peripheral surface of the outer casing. In this configuration, a plurality of connecting members are provided.

Further, in the invention of claim 3, a recess is provided on the outer peripheral side of the inner casing so as to surround the electrode terminal, and one side of the connecting member is inserted into the recess to insert the recess. The connecting member is positioned on the outer peripheral side of the inner casing.

[0022]

According to the structure of claim 1, the casing is
After the inner casing is molded on the outer peripheral side of each core member by the low-pressure resin mold, the outer casing is molded on the outer peripheral side of the inner casing by the high-pressure resin mold. Therefore, each core member, The coil bobbin and the like can be integrally positioned and fixed. As a result, it is possible to prevent positional displacement due to vibration from the outside and prevent water and the like from entering from the outside.

In particular, when the inner casing is molded with a resin mold, by making the resin filling pressure low, it is possible to prevent an excessive filling pressure from acting on the core member and to prevent the core member from cracking or the like. It can be reliably prevented from occurring.

On the other hand, when the outer casing is molded with a resin, the rigidity of the outer casing can be increased by increasing the pressure of resin filling, and the outer shell of the magnetostrictive torque sensor is made strong. Can be

According to the second aspect of the invention, one side of each electrode terminal is fixed to the coil bobbin, and one side of each connecting member is fitted and fixed to the electrode terminal. Each connection member can be positioned reliably,
Even if resin filling pressure is applied during molding of the inner casing and the outer casing, it is possible to prevent the electrode terminals and the connecting members from being displaced. As a result, electrical connection between each electrode terminal and each connection member can be surely made.

According to the invention of claim 3, the connecting member is inserted into the concave portion formed on the outer peripheral surface of the inner casing, the connecting member is positioned on the outer peripheral surface of the inner casing, and then the inner casing is formed. The outer casing is molded by resin molding from the outer peripheral side. As described above, since the connecting member is inserted into the recess, it is possible to reliably prevent the connecting member from being displaced due to the resin filling pressure. Thereby, the electrical connection between each electrode terminal and each connection member can be made more reliably.

[0027]

Embodiments of the present invention will be described below with reference to FIGS.

First, a first embodiment of the present invention will be described with reference to FIGS. In the embodiments, the same components as those of the above-described conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, reference numeral 30 denotes a cylindrical casing that constitutes the outer shell of the magnetostrictive torque sensor according to this embodiment. The casing 30 surrounds the inner casing 31 and the outer peripheral side of the inner casing 31. Outer casing 3
It has a double cylinder structure consisting of two.

That is, reference numeral 31 denotes an inner casing which constitutes an inner cylinder of the casing 30, and the inner casing 31 is formed of a resin material in a cylindrical shape, and inside thereof, core members 33, 33, a coil bobbin 36, which will be described later, are formed. 36, coils 41, 41, etc. are accommodated.

Here, FIG. 2 shows a state in the middle of manufacturing the magnetostrictive torque sensor, which is in a previous stage of forming the outer casing 32 on the outer side of the inner casing 31 (magnetostrictive shaft 3, each bearing). 4 etc. are not inserted).
In FIG. 2, the chamfered portion 31A is located at an intermediate position in the axial direction of the inner casing 31 and is provided at one position on the outer peripheral surface thereof.
Are formed. Then, as shown in FIG. 3, on the surface of the chamfered portion 31A, two positioning recesses 31B and 31B that are circularly opened and a positioning recess 31 that is an elongated groove.
C are recessed, and a total of four electrode terminals 42, 42, ... That is, the positioning recesses 31B and 31C are formed so as to surround the electrode terminals 42.

The inner casing 31 is molded by a low pressure resin mold so as to surround the outer peripheral side of the core member 33. That is, the inner casing 31 is
The core member 33, the coil bobbins 36 and the like are integrally assembled, and the core member 33 and the coil bobbin 36 are integrally assembled and inserted into a mold for molding the inner casing 31, and resin molding is performed. The resin filling pressure at this time is low enough not to cause cracks in the core member 33 or compressively deform the core member 33, the coil bobbin 36 and the like (for example, 30 to 50 kg / cm).
² ) is set.

Reference numeral 32 denotes an outer casing which constitutes an outer cylinder of the casing 30, and the outer casing 32 is formed of a resin material in a cylindrical shape. Further, the outer casing 32 is located on both sides of the tubular portion 32A surrounding the outer peripheral side of the inner casing 31 in the axial direction of the tubular portion 32A, and the annular projections 32B, 3 projecting radially inward.
2B and bearing accommodating portions 32C and 32C that accommodate the bearings 4 and 4 located on both axially outer sides of the respective annular protrusions 32B.

A connector insertion portion 32D for inserting a connector 45, which will be described later, is located at an intermediate position in the axial direction of the cylindrical portion 32A, and at one location (upper side in FIG. 1) on the outer peripheral surface thereof.
Are recessed, and connection members 43, 43, etc., which will be described later, project inside the connector insertion portion 32D.

Here, the outer casing 32 is molded by a high-pressure resin mold so as to surround the outer peripheral side of the inner casing 31. That is, the outer casing 32 is formed by inserting the inner casing 31 in which the core members 33, the coil bobbins 36, and the like are integrated into a mold for molding the outer casing 32 and filling the inner casing 31 with resin. To be done. The resin filling pressure at this time is set to a high pressure (for example, 500 to 1000 kg / cm ² ) as compared with the resin filling pressure at the time of molding the inner casing 31. As a result, the outer casing 32 has sufficient strength to form the outer shell of the magnetostrictive torque sensor.

Reference numerals 33 and 33 denote a pair of core members provided inside the inner casing 31 so as to surround the outer peripheral side of the magnetostrictive shaft 3, and each core member 33 is substantially the same as each core member 8 of the prior art. It is formed of a magnetic material such as.

Here, FIG. 4 shows the core member 33 on one side extracted from the pair of core members 33, 33 in FIG. And in FIG. 4, the core member 33
Is composed of a tubular core piece 34 and an annular core piece 35. The tubular core piece 34 of each core member 33 has an annular plate portion 34A in which an insertion hole 34A1 for inserting the magnetostrictive shaft 3 is formed in the center thereof. And a tubular portion 34B, and the tip end side of the tubular portion 34B is an abutting surface 34C. In addition, the tubular portion 34
B has a fitting groove 34D extending axially from the abutment surface 34C.
And a resin filling groove 34E are formed, and the fitting groove 34D is
It fits into the connecting portion 39 of each coil bobbin 36, which will be described later, and serves as a filling port for filling the resin material together with the resin filling groove 34E when the inner casing 31 is molded.

On the other hand, each annular core piece 35 is a tubular core piece 34.
An annular hole corresponding to the annular plate portion 34A is formed, and an insertion hole 35A through which the magnetostrictive shaft 3 is inserted is formed in the central portion thereof. Each annular core piece 35 has a thickness dimension corresponding to an annular core piece insertion fitting portion 40 described later, and corresponds to the fitting groove 34D of the tubular core piece 34 on the outer peripheral side of each annular core piece 35. A fitting groove 35B is formed.

Reference numerals 36 and 36 denote a pair of coil bobbins provided in the inner casing 31. Here, FIGS. 5 and 6 show one coil bobbin 36 extracted from each coil bobbin 36 in FIG. The coil bobbin 36, as shown in FIG.
7, an annular spacer portion 38, and a connecting portion 39, which are integrally formed of a resin material.

The winding portion 37 is composed of a shaft portion 37A formed in a tubular shape, and annular flange portions 37B, 37B protruding radially outward from both end sides of the shaft portion 37A. .

The annular spacer portion 38 is provided coaxially with the winding portion 37, separated from the winding portion 37 by a predetermined distance. Further, the annular spacer portion 38 is integrally formed as an annular flat plate adjacent to the winding portion 37,
The end surface of the coil bobbin 36 is an abutment surface 38A that abuts the annular spacer portion 38 of the other coil bobbin 36. Then, two engaging projections 3 are provided as engaging parts on the abutting surface 38A.
8B and two engagement holes 38C are alternately formed in the circumferential direction of the annular spacer portion 38 at angular intervals of, for example, about 90 degrees.

Further, the winding portion 37 and the annular spacer portion 38 are connected by a connecting portion 39. That is, the connecting portion 39 is formed in a substantially rectangular plate shape, and one end side thereof is connected to one flange portion 37B of the winding portion 37 and the other end side thereof is connected to the annular spacer portion 38, respectively. Then, the connecting portion 39
Positions the annular spacer portion 38 at a predetermined distance from the winding portion 37, and forms an annular core piece insertion portion 40 between the winding portion 37 and the annular spacer portion 38. Further, on the upper surface of the connecting portion 39, the base ends of the electrode terminals 42, 42 are provided.

Reference numerals 41 and 41 denote shaft portions 37 of the winding portions 37.
A coil formed by winding a winding around the outer peripheral surface of A is shown. Each coil 41 is substantially the same as each coil 10 of the prior art, and one end and the other end (both not shown) of the winding of each coil 41 are shown. ) Are electrically connected to the electrode terminals 42, 42, respectively.

Reference numerals 42, 42, ... Denote two electrode terminals (four in total) provided in the connecting portion 39 of each coil bobbin 36, and the base end side of each electrode terminal 42 is the coil bobbin 3 respectively.
6, each of the positioning recesses 31B and 31C is formed in the chamfered portion 31A as shown in FIG.
It is exposed inside. That is, the inner casing 31 is molded by surrounding the outer peripheral side of the core member 33, the coil bobbin 36, and the like with a low-pressure resin mold, so that the base end side of each electrode terminal 42 is the connecting portion 3 of each coil bobbin 36.
9 and 9 are buried in the resin of the inner casing 31, and only the tips of the electrode terminals 42 are positioned in the positioning recesses 31B, 31.
It is arranged so as to be exposed in C. Further, the winding ends of the coils 41 are connected to the base ends of the electrode terminals 42, respectively.

Reference numerals 43 and 43 denote two connecting members respectively inserted in the respective positioning recesses 31B of the inner casing 31, and each connecting member 43 is made of a hard metal material into a cylindrical shape as shown in FIG. Is formed and the inner peripheral side is the insertion hole 4
It is 3A. The base end side of each connecting member 43 is inserted into each positioning recess 31B of the inner casing 31, and in this state, the insertion hole 43A is fitted and fixed to the tip end side of the electrode terminal 42. Thereby, the connection members 43 are electrically connected to the electrode terminals 42, respectively.

On the other hand, the tip side of each connecting member 43 penetrates the cylindrical portion 32A of the outer casing 32 and is exposed at the connector insertion portion 32D of the outer casing 32. That is, by molding the outer casing 32 by surrounding the outer peripheral side of the inner casing 31 with a high-pressure resin mold, the base end side of each connecting member 43 is buried in the resin of the outer casing 32, and each connecting member 43 is formed. Is disposed so that only the front end of the connector is exposed at the connector insertion portion 32D.

Reference numeral 44 denotes another connecting member inserted into each positioning recess 31C of the inner casing 31, and the connecting member 44 is made of a metallic material and is located at the base end side as shown in FIG. Is the positioning recess 3 of the inner casing 31.
It becomes the standing plate portion 44A formed in a shape that fits with 1C,
The portion located on the tip side is a columnar portion 44B having a cylindrical shape. Further, insertion holes 44C, 44C are formed in both the left and right sides of the standing plate portion 44A so as to penetrate in the vertical direction.

The connecting member 44 is inserted into the positioning recess 31C on the base end side thereof in substantially the same manner as the connecting members 43. In this state, the insertion hole 44C is inserted into each electrode terminal 4
They are fitted and fixed to the tip ends of the two. Thereby, the connecting member 44 is electrically connected to each electrode terminal 42.

The two electrode terminals 42, 42 connected to the second connecting member 44 both carry signals of the same potential and the same current (for example, both are connected to the ground of the detection circuit). ), The second connecting members 44 are electrically short-circuited to reduce the number of connecting members.

On the other hand, the tip end side of the connecting member 44 penetrates the cylindrical portion 32A of the outer casing 32, and the outer casing 3
It is exposed at the second connector insertion portion 32D. That is, like the connecting member 43, by molding the outer casing 32 by surrounding the outer peripheral side of the inner casing 31, the base end side of each connecting member 44 is buried in the resin of the outer casing 32, and each connecting member is connected. Only the tip portion of the member 44 is disposed so as to be exposed at the connector insertion portion 32D.

Reference numeral 45 denotes a connector into which the connector insertion portion 32D of the outer casing 32 is inserted.
Receiving side electrodes 45A, 45A, ... Are provided inside, and each receiving side electrode 45A is connected to an external detection circuit via a lead wire 46. Then, when the connector 45 is inserted into the connector insertion portion 32D, the tip ends of the connection terminals 43 and 44 are inserted into the receiving side electrode 45A, whereby each coil 41 is connected to each electrode terminal 42 and each electrode terminal 42. It is electrically connected to an external detection circuit via the connecting members 43 and 44, each receiving side electrode 45A, and the lead wire 46. An O-ring or the like (not shown) is provided at the tip of the outer peripheral side of the connector 45. When the connector 45 is inserted into the connector insertion portion 32D, the O-ring or the like causes the inside of the connector insertion portion 32D to be removed. It is designed to prevent external water and the like from entering.

The magnetostrictive torque sensor according to this embodiment has the above-mentioned structure, and there is no particular difference in the basic operation from the prior art.

Therefore, a method of manufacturing the magnetostrictive torque sensor will be described with reference to FIGS.

First, in FIG. 7, each coil 41 is wound around each winding portion 37, and the end side of each coil 41 is connected to each electrode terminal 42. Then, while aligning the connecting portions 39 of the coil bobbins 36 with each other, the engaging protrusions 38B and the engaging holes 38C of the annular spacer portions 38 are indicated by arrows A.
Abutting surface 38A of each annular spacer 38
Abut each other.

Next, each annular core piece 35 is inserted into the annular core piece insertion portion 40 of each coil bobbin 36 from the direction of arrow B,
The fitting groove 35B of each annular core piece 35 is formed in each coil bobbin 3
6 is connected to the connecting portion 39. And each coil bobbin 3
Each tubular core piece 34 is inserted in the arrow C direction from both the left and right sides of 6, and each tubular core piece 34 is fitted with the fitting groove 34D into the connecting portion 39 of each coil bobbin 36. Core piece 34
The abutting surface 34C of abutting against the annular core pieces 35 is abutted.

In this way, the core members 33, the coil bobbins 36, etc. are assembled as shown in FIG. 8 and the members are positioned relative to each other.

Next, each core member 33 and each coil bobbin 36 assembled as shown in FIG.
1. Inserting into a molding die and filling with resin, and as shown in FIG. 9, on the outer peripheral side of each core member 33, each coil bobbin 36, etc., an inner casing 31, a chamfered portion 31A, and each positioning recess 31B. , 31C are formed. At this time, the resin filling pressure is set to a low pressure so as to prevent cracks from being generated in each core member 33.

Next, after inserting the connecting members 43 and 44 into the respective positioning recesses 31B and 31C of the inner casing 31 as shown by the arrows in FIG. 6, the inner casing 31 is molded with a metal for molding the outer casing 32. It is inserted into the mold and filled with resin, and as shown in FIG. 10, the outer casing 32, the connector insertion portion 32D and the like are formed on the outer peripheral side of the inner casing 31. At this time, the resin filling pressure is set to a relatively high pressure in order to increase the rigidity of the outer casing 32.

Here, the connecting members 43 and 44 are formed by the high resin filling pressure when the outer casing 32 is molded.
There is concern that it may be deformed or misaligned. But,
Since each of the connecting members 43 and 44 is formed of a hard metal material, it does not deform, and each of the connecting members 43 and 44 does not deform.
The base end side of 44 is the positioning recess 3 of the inner casing 31.
Since they are inserted into 1B and 31C respectively, they will not be displaced. Thereby, the connection members 43, 44
The tip side of the connector is the connector insertion portion 32D of the outer casing 32.
Each of them is accurately arranged so as to project at a predetermined position therein.

Finally, each bearing 4 is mounted in each bearing accommodating portion 32C of the outer casing 32, and the magnetostrictive shaft 3 is mounted in the axial center of the outer casing 32 to complete the magnetostrictive torque sensor according to this embodiment. To do.

Thus, according to this embodiment, the inner casing 31 is surrounded by surrounding the outer peripheral sides of the core members 33, the coil bobbins 36, etc. with the low-pressure resin mold.
And the outer casing 32 is formed by surrounding the outer peripheral side of the inner casing 31 with a high-pressure resin mold.
1, each core member 33, each coil bobbin 36 and the like can be accurately positioned and fixed, and the outer casing 32 causes the entire inner casing 31 including the core member 33, each coil bobbin 36 and the like to be a magnetostrictive shaft. 3 can be accurately positioned and fixed. Further, even if the vehicle is subjected to vibration or the like due to traveling, the positional relationship can be maintained, the accuracy of torque detection can be improved, and the durability can be significantly improved.

By forming the outer casing 32 with a resin molding, the outer peripheral surface of the inner casing 31 comes into close contact with the inner peripheral surface of the outer casing 32, so that water or the like enters the outer casing 32. It is possible to reliably prevent this, and it is possible to prevent malfunctions in torque detection and improve reliability.

Furthermore, since the resin filling pressure is set to a low pressure when the inner casing 31 is molded, the core members 33, the coil bobbins 36, etc. are not strongly pressed by the resin, and the core members 33, the coil bobbins 36 are not pressed. It is possible to reliably prevent the core member 33 from being cracked and the coil bobbin 36 from being compressed and deformed due to excessive pressure applied to etc., and it is possible to prevent defective products and improve the yield. .

Further, according to this embodiment, the connecting members 43 and 4 are connected to the electrode terminals 42 to which the coil bobbins 36 are fixed.
Since the insertion holes 43A and 44C of No. 4 are fitted and fixed, the electrode terminals 42 and the connecting members 43 can be positioned in a state where they are electrically and reliably connected. As a result, it is possible to reliably prevent the torque detection signal from being deteriorated due to noise or an unexpectedly large increase in resistance in the electrical path connecting the coils 41 and the connector 45. Therefore, the accuracy of torque detection can be significantly improved.

Further, the chamfered portion 31 of the inner casing 31
The respective positioning recesses 31B and 31C formed in A are provided,
The connecting members 43, 44 are connected to the positioning recesses 31B, 31
Since it is configured to be inserted into C, even if a high-pressure resin mold is applied to form the outer casing 32, it is possible to reliably prevent the connection members 43 and 44 from being displaced. Thereby, each electrode terminal 42 and each connection member 43, 4
The electrical connection with 4 can be performed more reliably.

Next, a second embodiment of the present invention is shown in FIG. 11, which is characterized in that the connecting member inserted in the recess of the inner casing is positioned more reliably. The shapes of the concave portion of the inner casing and the connecting member are as illustrated. In this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals,
The description will be omitted.

In the figure, reference numerals 51A and 51A denote positioning recesses as recesses according to the present embodiment, which are recessed at two positions of the chamfered portion 31A of the inner casing 31, and each of the positioning recesses 51A has an opening shape of the first shape. Unlike each positioning recess 31B according to the first embodiment, the positioning recess 31B has an oval shape. 51
B shows another positioning recess as a recess recessed in the chamfered portion 31A of the inner casing 31, and the positioning recess 5
The opening shape of 1B is substantially T-shaped, unlike the positioning recess 31C according to the first embodiment. Further, a total of four electrode terminals 42, 42, ... Project in the respective positioning recesses 51A, 51B, as in the first embodiment.

Reference numerals 52 and 52 denote connection members according to the present embodiment. Each of the connection members 52 is positioned in the positioning recess 51A so that the base end side is inserted into the facing positioning recess 51A.
The insertion fitting portion 52A has the same shape as the opening shape, and the tip end side is a columnar column portion 52B. Also,
A terminal receiving portion 52C into which the electrode terminal 42 is fitted is formed in the insertion portion 52A.

Reference numeral 53 shows another connecting member according to the present embodiment. The connecting member 53 has the same shape as the opening of the positioning recess 51B so that the base end is inserted into the facing positioning recess 51B. Becomes the formed insertion portion 53A,
The front end side is a columnar column portion 53B. Further, terminal receiving portions 53C and 53C into which the electrode terminals 42 and 42 are fitted are formed on both left and right ends of the insertion portion 53A.

Then, after inserting the fitting portions 52A, 53A of the connecting members 52, 53 into the positioning recesses 51A, 51B, respectively, the outsides thereof are surrounded by the resin of the outer casing 32, whereby the respective connecting portions are connected. The insertion fitting portions 52A and 52A of the members 52 and 53 are embedded in the resin, and
Only the tip ends of B and 53B are arranged so as to be exposed from the connector insertion portion 32D of the outer casing 32. Further, in a state where the insertion fitting portions 52A and 53A of the respective connecting members 52 and 53 are inserted into the respective positioning recessed portions 51A and 51B, the respective electrodes are provided in the respective terminal receiving portions 52C and 53C of the respective connecting members 52 and 53. The terminals 42 are fitted together. As a result, the connection members 52, 53 are electrically connected to the electrode terminals 42, respectively, and the positioning recesses 51A,
Positioned within 51B.

According to the present embodiment having the above-described structure, the inner casing 3 is substantially the same as the first embodiment.
Each connection member 5 in each positioning recess 51A, 51B of 1
2, 53 can be inserted and fitted, and the connection members 52, 53 can be positioned while being electrically connected to the electrode terminals 42. As a result, it is possible to reliably prevent the connection members 52 and 53 from being displaced due to the resin filling pressure when the outer casing 32 is molded.

Next, a third embodiment of the present invention is shown in FIG. 12. The feature of this embodiment is that the projections 61, 61 are formed on the inner side surfaces of the positioning recesses 51A, 51B described in the second embodiment. 、…
And each connecting member 5 described in the second embodiment.
.. are formed in the positioning recesses 51A and 51B, the protrusions 61 of the positioning recesses 51A and 51B are connected to the connecting members 52. , 53 are engaged with the respective groove portions 62.

According to the present embodiment having the above-described structure, each connecting member 5 is also the same as in the first and second embodiments.
2 and 53 can be accurately positioned in the respective positioning recesses 51A and 51B.

In each of the above-mentioned embodiments, the positioning recesses 31B, 31C (51A, 51) of the inner casing 31 are arranged.
Insert each connecting member 43, 44 (52, 53) into B),
Although it has been described that each electrode terminal 42 and each connecting member 43, 44 are connected, the present invention is not limited to this, and each electrode terminal 4 is connected.
2 may be formed to be long, and the tip end side of each electrode terminal 42 may penetrate the inner casing 31 and the outer casing 32 and be exposed in the connector insertion portion 32D.

Further, in each of the above-mentioned embodiments, the case where it is used for detecting the torque of the automobile engine has been described as an example.
It can also be used for other torque detection such as torque of the rotating shaft of the electric motor.

[0076]

As described above in detail, according to the invention of claim 1, an inner casing formed by a low pressure resin mold on the outer peripheral side of the core member, and a high pressure resin mold on the outer peripheral side of the inner casing. Since the outer casing is formed by the outer casing, the inner casing can accurately position and fix the core members, the coil bobbins, and the like, and the outer casing includes the core members and the coil bobbins. Moreover, the entire inner casing can be accurately positioned and fixed to the magnetostrictive shaft. As a result, the durability against the vibration applied from the outside can be significantly improved, and the accuracy of torque detection can be improved.

Further, since the inner peripheral surface of the outer casing is in close contact with the outer peripheral surface of the inner casing, no gap is formed between the outer casing and the inner casing, and water or the like is kept inside the casing. Intrusion can be reliably prevented, malfunction of torque detection, etc. can be prevented, and reliability can be improved.

Further, since the inner casing is molded by the low pressure resin mold, it is possible to surely prevent the core member from being cracked and the like, and prevent defective products from being produced to improve the yield. You can

According to the invention of claim 2, one side of each electrode terminal is fixed to the coil bobbin, and one side of each connecting member is fitted and fixed to the electrode terminal. It is possible to accurately position and firmly fix each connecting member in an electrically connected state. As a result, it is possible to reliably prevent the electrode terminals and the connecting members from being deformed or displaced due to the resin filling pressure when molding the inner casing and the outer casing. Therefore, each detection and excitation coil is connected to each electrode terminal,
It is possible to reliably connect to an external detection circuit via each connection member, and it is possible to improve the accuracy of torque detection.

Further, according to the invention of claim 3, a recess is provided on the outer peripheral side of the inner casing so as to surround the electrode terminal, and one side of the connecting member is inserted into the recess. Since the connection member is configured to be positioned while being electrically connected to the electrode terminal, it is possible to reliably prevent the connection member from being displaced due to the resin filling pressure during molding of the outer casing. The member and the electrode terminal can always be reliably connected, and the yield in manufacturing the magnetostrictive torque sensor can be significantly improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a magnetostrictive torque sensor according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an inner casing in FIG.

FIG. 3 is an exploded perspective view showing, in an enlarged manner, a state in which a connecting member is fitted into a positioning recess of an inner casing.

FIG. 4 is an exploded perspective view showing a core member in FIG.

5 is a front view showing a coil bobbin in FIG. 1. FIG.

FIG. 6 is a sectional view taken along the line VI-VI in FIG.

FIG. 7 is an exploded perspective 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 each core member and each coil bobbin are assembled.

9 is a vertical cross-sectional view showing a state in which an inner casing is formed outside each core member and each coil bobbin in FIG.

10 is a vertical cross-sectional view showing a state in which an outer casing is formed outside the inner casing in FIG.

FIG. 11 is an exploded perspective view showing a state in which a connecting member is fitted into a positioning recess formed in the inner casing of the magnetostrictive torque sensor according to the second embodiment of the present invention.

FIG. 12 is an exploded perspective view showing a state in which a connecting member is fitted into a positioning recess formed in an inner casing of a magnetostrictive torque sensor according to a third embodiment of the present invention.

FIG. 13 is a vertical sectional view showing a magnetostrictive torque sensor according to a conventional technique.

FIG. 14 is a longitudinal sectional view showing a magnetostrictive torque sensor according to another conventional technique.

[Explanation of symbols]

3 Magnetostrictive shaft 30 Casing 31 Inner casing 31B, 31C, 51A, 51B Positioning recess (recess) 32 Outer casing 33 Core member 36 Coil bobbin 37 Winding part 41 Coil (excitation and detection coil) 42 Electrode terminals 43, 44, 52, 53 Connection member

Claims (3)

[Claims] 1. A tubular casing, a magnetostrictive shaft rotatably supported by the casing, and at least a pair of tubular core members provided in the casing so as to surround an outer peripheral side of the magnetostrictive shaft. In order to detect the torque acting on the coil bobbin and the magnetostrictive shaft provided on the inner peripheral side of each core member as an electric signal,
In a magnetostrictive torque sensor including an excitation and detection coil formed by winding a coil around each coil bobbin, the casing includes a cylindrical inner casing formed by a low-pressure resin mold on the outer peripheral side of each core member. A magnetostrictive torque sensor, comprising: an outer casing formed by a high-pressure resin mold on the outer peripheral side of the inner casing. 2. The coil bobbin has one side fixed to the coil bobbin, the winding ends of the excitation and detection coils being connected thereto, and the other side extending radially outward to the outer peripheral surface of the inner casing. A plurality of exposed electrode terminals are provided, and a plurality of connecting members, one side of which is fitted and fixed to each of the electrode terminals and the other side of which is extended outward in the radial direction and exposed to the outer peripheral surface of the outer casing, are provided in the inner casing. The magnetostrictive torque sensor according to claim 1, wherein the magnetostrictive torque sensor is provided. 3. A recess is provided on the outer peripheral side of the inner casing so as to surround the electrode terminal, and one side of the connecting member is inserted into the recess to connect the connecting member to the inner casing. The magnetostrictive torque sensor according to claim 2, wherein the magnetostrictive torque sensor is configured to be positioned on the outer peripheral side.