JPH0555034U - Magnetostrictive torque sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] To suppress variations in the magnetic characteristics of the core member used in the magnetostrictive torque sensor, prevent the magnetic characteristics from varying due to vibration, and facilitate the assembly work. [Structure] A cylindrical projection 27 protruding in the axial direction is provided on the inner peripheral side of the tip of the abutting portion 25 of the core piece 22, and the other core piece 23 is provided on the inner peripheral side of the abutting portion 30 with the cylinder. The cylindrical recess 32 having a shape that engages with the protrusion 27 is provided, and the core pieces 22 and 23 are
When the core pieces 22, 23 are abutted so that the coil bobbin 8 and the like are accommodated in the bobbin accommodating portions 26, 31, the cylindrical protrusion 27 is engaged in the cylindrical concave portion 32 so that each core piece 22. , 23 are integrated to form the core member 21.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 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]

[Prior Art]

 7 to 10 show examples of 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, 1 is a cylindrical casing fixed to a vehicle body (not shown) of an automobile, 2 is rotatably disposed in the casing 1 through bearings 3 and 3, and is, for example, a propeller shaft, 1 shows a magnetostrictive shaft that constitutes an output shaft or a drive shaft, and the magnetostrictive shaft 2 is formed of a magnetostrictive material such as chrome molybdenum steel into a columnar shape, and a sensor portion 2A is integrally formed in the axial middle thereof. There is. Also, on the outer peripheral surface of the sensor portion 2A, a large number of one-side slit grooves 4, 4, ... Engraved at an angle of 45 ° downward, and facing each of the one-side slit grooves 4 are provided. A large number of other side slit grooves 5, 5, ... Engraved at an angle of 45 ° are provided.

Reference numerals 6 and 6 denote core members. The core members 6 are provided at two locations on one side and the other side of the inner circumference of the casing 1, and each core member 6 has a small air gap between it and the magnetostrictive shaft 2. The gap δ is formed, and the magnetic circuit shown in FIG. 10 is formed together with the magnetostrictive shaft 2 and the like. Here, each core member 6 is made of a magnetic material such as ferrite, and is configured by abutting core pieces 7, 7 described later in the axial direction.

Reference numerals 7, 7, ... Depict core pieces as a pair of half halves constituting the core member 6, and each of the core pieces 7 has a shaft insertion hole 7A formed at the center thereof and corresponds to the inner diameter of the casing 1. And an annular plate portion 7B formed in an annular shape with a different outer diameter, and a cylindrical abutting portion 7C extending in the axial direction from the outer peripheral side of the annular plate portion 7B and having a flat tip surface. ing. Here, a bobbin accommodating portion 7D is provided inside each of the core pieces 7, and the bobbin accommodating portion 7D collides the two core pieces 7, 7 in the axial direction (direction A shown in FIG. 8). When the core member 6 is formed in combination with each other, the coil bobbins 8 and 9 and the coils 10 and 11 which will be described later are housed inside the core member 6.

Reference numerals 8 and 9 denote one side coil bobbin and the other side coil bobbin respectively provided on the inner peripheral side of each core member 6, and each coil bobbin 8 and 9 has a cylindrical portion 8A formed of a resin material in a cylindrical shape. 9A, and annular collar portions 8B 1 and 9B integrally formed on both end sides of the respective tubular portions 8A and 9A. Reference numerals 10 and 11 denote one side coil and the other side coil as excitation and detection coils wound around the outer peripheral side of the shaft portions 8A and 9A of the coil bobbins 8 and 9, respectively, and the coils 10 and 11 are adjusted. A bridge circuit is constructed with a resistor and is connected to a detection circuit (not shown) including an oscillator and a differential amplifier. Here, each of the coils 10 and 11 is configured as an exciting coil which is excited by a high frequency voltage from an oscillator to generate a magnetic flux and a detecting coil which detects a magnetic flux passing through the magnetic circuit shown in FIG. Has been done.

Reference numerals 12 and 12 denote outer spacers provided at the ends of the core members 6 and 6, 13 denotes inner spacers disposed between the core members 6 and 6, respectively, and the spacers 12 and 13 are Each core piece 7 that constitutes each core member 6 is sandwiched from both sides in the axial direction. The core members 6, 6 and the like held in a state of being sandwiched by the spacers 12, 13 are fixed to the inner peripheral side of the casing 1 by a retaining ring 14 as shown in FIG.

The magnetostrictive torque sensor according to the prior art has the above-described configuration. When an AC voltage is applied to the coils 10 and 11 from the oscillator of the detection circuit, for example, as shown by a chain double-dashed line in FIG. A magnetic circuit is formed from each core member 6 to the magnetostrictive shaft 2 by the magnetic flux generated from each coil 10 and 11.

As shown in FIG. 10, the magnetic circuit includes a magnetic resistance R1 of each core member 6, magnetic resistances R2 and R2 of the air gap δ, magnetic resistances R3 of the coil bobbins 8 and 9, and the magnetostrictive shaft 2. Of the magnetic resistance R4, and the values of the magnetic resistances R1, R2, R3 and R4 are

[0010]

[Equation 1] Is required as.

Further, the self-inductance L of each coil 10, 11 is Rt and the number of coil turns is N, where Rt is the total magnetic resistance obtained by combining the magnetic resistances R1, R2, R3, and R4.

[0012]

## EQU2 ## It can be obtained as L = N ² / Rt.

When a counterclockwise torque T is applied to one end of the magnetostrictive shaft 2 as shown in FIG. 7, tensile stress + σ is generated along the one side slit groove 4 and the other side slit groove 5 is generated. A compressive stress −σ is generated along the line. As a result, in the case of a positive magnetostrictive shaft, the magnetic permeability μ of the magnetostrictive shaft 2 on the one side slit 4 side is increased by the tensile stress + σ, and the magnetic resistance R4 of the magnetostrictive shaft 2 decreases, while the other side slit. The magnetic permeability μ of the magnetostrictive shaft 2 on the 5 side decreases due to the compressive stress −σ, and the magnetic resistance R4 increases. As a result, the total magnetic resistance Rt of the one-side coil 10 decreases and the self-inductance L increases, while the other magnetic coil 11 of the other-side coil 11 increases the total magnetic resistance Rt and the self-inductance L decreases. The balance is lost and an output voltage corresponding to the torque T appears in the differential amplifier.

On the contrary, when a clockwise torque is applied to one end side of the magnetostrictive shaft 2, in the case of the positive magnetostrictive shaft, a compressive stress −σ is generated along the one-side slit groove 4 and the transparent stress is generated. Since the magnetic susceptibility μ decreases, tensile stress + σ is generated along the other side slit groove 5, and the magnetic permeability μ increases, the self-inductance L of the one-side coil 10 decreases and the self-inductance L of the other-side coil 11 increases. Then, the differential amplifier outputs a voltage corresponding to the opposite torque.

[0015]

[Problems to be solved by the device]

 By the way, in the above-mentioned magnetostrictive torque sensor according to the prior art, an alternating voltage is applied to the coils 10 and 11 to generate magnetic flux, and as shown in FIG. 10, the core members 6 and 6, the air gap δ, and the magnetostrictive shaft 2 are used. This torque is detected by utilizing the fact that the magnetic resistance R4 of the magnetostrictive shaft 2 changes due to the torque transmitted from the outside by forming a magnetic circuit extending over the torque.

However, in the prior art, the core member 6 is formed by simply abutting the pair of core pieces 7 and 7 at the abutting portions 7C of each other. It is difficult to position them in the casing 1 with the mating portions 7C abutted against each other, or to assemble the magnetostrictive torque sensor by aligning the relative positions of the annular plate portion 7B and the slit grooves 4 and 5. There is a problem. In particular, it is difficult to make the magnetic resistances of the one side coil 10 side and the other side coil 11 side uniform, and there is a problem that the torque detection characteristics vary from product to product.

When the vibration of the engine or the vehicle body is transmitted to the casing 1 of the magnetostrictive torque sensor, each core piece 7 constituting the core member 6 vibrates individually, and the magnetic resistance R1 of the core member 6 fluctuates. Therefore, there is a problem that accurate torque detection may not be possible.

Further, since the abutting portion 7C of each core piece 7 is formed flat, the core pieces 7 and 7 are easily slipped, and each core piece 7 is displaced during assembly to deform the core member 6. However, there is a problem that the assembly work is difficult.

The present invention has been made in view of the above-mentioned problems of the prior art. It is possible to suppress fluctuations in torque detection characteristics, prevent erroneous detection due to vibration, and facilitate assembly work. The present invention aims to provide the magnetostrictive torque sensor.

[0020]

[Means for Solving the Problems]

 The feature of the configuration adopted by the first invention to solve the above-mentioned problems is that the core member is composed of a pair of halves divided into two in the axial direction of the magnetostrictive shaft. One half-divided body is provided with a cylindrical projection projecting in the axial direction at the abutment portion with the other half-divided body, and the other half-divided body is provided with the abutment portion with the one half-divided body. This is because a cylindrical recess that engages with the cylindrical projection is provided.

The feature of the configuration adopted by the second invention is that the core member sandwiches the core member with a pair of halves divided in the axial direction of the magnetostrictive shaft. It is composed of a clamp member that is integrally fixed together.

The feature of the configuration adopted by the third invention is that the core member is composed of a pair of halves divided into two in the radial direction of the magnetostrictive shaft, including each annular plate portion, The abutting portion of the body is formed with a convex portion and a concave portion that engage with each other at the positions of the annular plate portions.

Furthermore, the feature of the configuration adopted by the fourth invention is that the core member includes a pair of halves which are divided into two in the radial direction of the magnetostrictive shaft including the annular plate portions, and the halves. It is configured by a clamp member that is clamped from the outside in the radial direction and integrally fixed.

[0024]

With the above configuration, if the projection or the convex portion and the recess provided on each half body are engaged with each other, or the two half bodies are sandwiched by the clamp members, each half body is collided. The halves can be easily positioned with the abutting part abutting against each other, and the halves can be prevented from shifting in position. As a result, the magnetic resistance as the core member can be made uniform, and the halves are individually vibrated by the vibration of the engine, etc., and the magnetic resistance of the core member as a whole changes. It is possible to prevent the core member from being deformed.

[0025]

【Example】

 Hereinafter, an 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.

First, FIGS. 1 and 2 show a first embodiment of the present invention.

In the figure, reference numeral 21 denotes a core member used in the present embodiment. The core member 21 is a pair of half-divided bodies made of a magnetic material such as ferrite, similar to the core member 6 described in the prior art. It is composed of a core piece 22 and a core piece 23.

Here, reference numeral 22 denotes a core piece as one half-split body, and the core piece 22 is substantially the same as the core piece 7 described in the prior art, and has an annular shape with a shaft insertion hole 24A formed in the center. Although it is composed of a plate portion 24, a tubular abutting portion 25 and a bobbin accommodating portion 26, the abutting portion 25 of the core piece 22 has a tubular projection axially protruding from the inner peripheral side of the tip surface. 27 is provided on the outer surface of the core piece 22, and is formed radially outward from one location outside the shaft insertion hole 24A of the annular plate portion 24, and the tip end of the abutting portion 25 in the axial direction is formed. A rectangular shallow clamp mounting groove 28 extending to the side is formed.

The core piece 23, which is the other half-divided body, has an annular plate portion 29 having a shaft insertion hole 29A, a cylindrical abutting portion 30, and a bobbin accommodating portion 31 in substantially the same manner as the core piece 7. However, the abutting portion 30 of the core piece 23 is formed with a cylindrical recess 32 that engages with the cylindrical projection 27 on the inner periphery on the tip side, and the outer surface of the core piece 23 is A clamp mounting groove 33 similar to the core piece 22 is formed.

Reference numeral 34 denotes a U-shaped clamp as a clamp member, and the U-shaped clamp 34 is formed as a thin metal plate having a spring property from a magnetic material such as iron, and the clamp mounting grooves 28, A connecting portion 34A having the same width as that of the intermediate portion 33 is formed in the middle, and sandwiching portions 34B and 34B bent to the same side from the connecting portion 34A are formed at both ends of the connecting portion 34A to form a substantially U-shape.

Then, the coil bobbin 8 and the like are accommodated in the respective bobbin accommodating portions 26 and 31, the cylindrical protrusion 27 is engaged with the inner side of the cylindrical concave portion 32, and the clamp mounting grooves 28 and 33 are aligned with each other. Then, the core pieces 22 and 23 are abutted in the direction of arrow B in FIG. Here, when the U-shaped clamp 34 is fitted into the clamp mounting grooves 28 and 33 in the direction indicated by the arrow C in FIG. 2, the holding portions 34B of the U-shaped clamp 34 are connected to the connecting portion 34A. The annular plates 24 and 29 are pressed from both ends to firmly integrate the core pieces 22 and 23. Here, the clamp mounting grooves 28 and 33 are shallowly formed on the surfaces of the core pieces 22 and 23, and when a magnetic circuit is formed from the core member 21, the magnetostrictive shaft 2, etc., the clamp mounting grooves 28 and 33 are mounted. The shapes of the grooves 28 and 33 and the U-shaped clamp 34 are taken into consideration so as not to adversely affect the magnetic flux.

Thus, the core member 21 is completed, and like the core member 6 described in the prior art, the core member 21 is mounted on the inner peripheral side of the casing 1 at two positions, one side and the other side, and the shaft member 21 is attached. The magnetostrictive shaft 2 is inserted into the insertion holes 24A and 29A to be assembled as a magnetostrictive torque sensor.

The magnetostrictive torque sensor according to the present embodiment has the configuration described above, and its basic operation is not particularly different from that according to the prior art.

However, in this embodiment, the core piece 22 has the cylindrical protrusion 27 projecting from the inner peripheral side of the abutting portion 25 toward the tip end side in the axial direction, and the annular plate portion 24 to the abutting portion 25 on the outer surface. A clamp mounting groove 28 extending to the front end side in the axial direction is provided, and a cylindrical recess 32 that engages with the cylindrical projection 27 is provided on the inner periphery of the abutting portion 30 on the front end side of the core piece 23. A clamp mounting groove 33 similar to the core piece 22 is provided, and the core pieces 22 and 23 are axially abutted to form the core member 21. Since the U-shaped clamp 34 is fitted into the core to sandwich the core pieces 22 and 23, the cylindrical protrusion 27 is engaged with the inside of the cylindrical recess 32 to position the core pieces 22 and 23, The abutting part 25 of the core piece 22 and the abutting part 30 of the core piece 23 are displaced in the axial direction, It is possible to prevent the relative positions of the core pieces 22 and 23 from changing due to the vibration of the gin or the like, and changing the magnetic resistance of the core member 21 as a whole.

In particular, in this embodiment, since the core pieces 22 and 23 are strongly pressed and pinched by the U-shaped clamp 34 in the direction in which the core pieces 22 and 23 collide with each other, the core pieces 22 and 23 should be in close contact with each other without a gap. It is possible to improve stability against vibration.

Therefore, when the magnetostrictive torque sensor is assembled, it is possible to suppress variations in torque detection characteristics among products, prevent erroneous detection due to engine vibration, etc. 22 and 23 can be integrally handled as the core member 21, and the inconvenience of handling at the time of assembly can be eliminated.

In the above embodiment, when the core pieces 22 and 23 are axially abutted, the cylindrical protrusions 27 and the cylindrical concave portions 32 of the abutting portions 25 and 30 are engaged with each other. The case where the U-shaped clamp 34 is mounted in the state has been described as an example, but the present invention is not limited to this, and for example, without using the U-shaped clamp 34, the cylindrical protrusion 27 and the cylindrical concave portion are not used. The core member 21 may be integrated by engaging with 32, or conversely, the core pieces 22 and 23 may be integrated only by the U-shaped clamp 34. ..

Further, in the above-mentioned embodiment, the core pieces 22 and 23 are respectively provided with the clamp mounting grooves 28 and 33 at one place, and the core pieces 22 and 23 are clamped by one U-shaped clamp 34 as an example. However, two or more clamp mounting grooves 28 and 33 may be provided in each core piece 22 and 23, and the same number of U-shaped clamps 34 may be mounted.

Next, FIG. 3 shows a second embodiment of the present invention. The feature of this embodiment is that the core member is divided into two in the axial direction of the magnetostrictive shaft, and the core member is divided into two halves. The core piece is provided with a male threaded portion as a cylindrical protrusion at the abutting portion of one core piece, and the female threaded portion as a cylindrical recessed portion is provided at the abutting portion of the other core piece. Especially.

In the figure, reference numeral 41 denotes a core member used in the present embodiment, and the core member 41 is composed of a pair of core pieces 42 and 43 serving as half halves.

Here, reference numeral 42 denotes a core piece as one half-split body, and the core piece 42 has a shaft insertion hole 44 A bored in the center thereof in substantially the same manner as the core piece 22 of the first embodiment. Although it is composed of an annular plate portion 44, a cylindrical abutting portion 45, and a bobbin accommodating portion 46, the abutting portion 45 of the core piece 42 projects axially from the inner circumference of the tip end side. A male screw portion 47 as a cylindrical protrusion is provided, and a screw groove 47A is formed on the outer peripheral side of the male screw portion 47.

The core piece 43 as the other half is also similar to the core piece 23, the annular plate portion 48 having the shaft insertion hole 48 A, the cylindrical abutting portion 49 and the bobbin accommodating portion 50. However, the abutting portion 49 of the core piece 43 is formed with a female screw portion 51 as a cylindrical recess that engages with the male screw portion 47 on the inner peripheral side, and the inner peripheral surface of the female screw portion 51 is formed. Has a thread groove 51A.

Then, the coil bobbins 8 and the like are accommodated in the bobbin accommodating portions 46 and 50 of the core pieces 42 and 43, and the abutting portions 45 and 49 are opposed to each other and abutted in the arrow D direction, so that the abutting portions 45 and 49 are circumferentially arranged. By rotating and screwing the male screw part 47 to the female screw part 51 of the core piece 43, the core member 41 is integrated, and the core member 41 is assembled as a magnetostrictive torque sensor like the core member 21 of the above-mentioned embodiment. ..

This embodiment has the configuration described above, and the same effects as those of the first embodiment can be obtained by this embodiment as well, but particularly according to this embodiment, the core portion is The core member 41 can be firmly configured without increasing the number of parts without using an accessory such as a clamp member on the outside of the material 41. Once the core member 41 is configured, each core piece 42 can be formed. , 43, the male screw portion 47 and the female screw portion 51 are firmly fixed, and when assembled into a magnetostrictive torque sensor, the stability against external vibration and the ease of handling during assembly work can be further improved. it can.

Next, FIGS. 4 to 6 show a third embodiment of the present invention. The feature of this embodiment is that the core member is a pair of halves divided into two in the radial direction of the magnetostrictive shaft. This is because it is composed of two core pieces, and a semi-annular plate portion obtained by dividing an annular plate portion into two is provided on both end sides of each core piece.

In the figure, reference numeral 61 denotes a core member used in this embodiment, and the core member 61 is configured by abutting two core pieces 62, which will be described later, in a radial direction.

Reference numerals 62 and 62 denote core pieces as halves made of a magnetic material such as ferrite. Each core piece 62 is formed by dividing a cylinder into two in the radial direction as shown in FIG. , A semi-cylindrical portion 64 whose inner side is the bobbin accommodating portion 63, and semi-annular plate portions 65 and 66 which are located at both axial ends of the semi-cylindrical portion 64 and extend inward in the radial direction. Semicircular shaft insertion grooves 65A and 66A are formed on the inner peripheral sides of the respective semi-annular plate portions 65 and 66. The end surfaces of the semi-annular plate portions 65 and 66, together with both ends of the semi-cylindrical portion 64, form abutting portions 65B, 66B and 64A with respect to the opposing core piece 62.

Here, in the abutting portion 65B of each semi-annular plate portion 65, recesses 67, 67, which are rectangular notches located on both sides in the radial direction of the shaft insertion groove 65A, are formed. In the abutting portion 66B of the portion 66, quadrangular convex portions 68, 68 that engage with the respective concave portions 67 are formed at positions corresponding to the respective concave portions 67, respectively.

On the other hand, the semi-cylindrical portion 64 of each core piece 62 is provided with a shallow clamp mounting groove 69 extending from one end in the circumferential direction along the outer peripheral surface over 100 ° or more.

Reference numeral 70 denotes a C-shaped clamp as a clamp member. The C-shaped clamp 70 is formed by bending, for example, a metal plate material similar to the U-shaped clamp 34 described in the first embodiment into an arc shape and contracting it. ， It is formed so that the diameter can be expanded.

As shown in FIG. 4, the two core pieces 62, 62 are arranged such that the semi-annular plate portion 65 and the semi-annular plate portion 66 are engaged by the concave portions 67 and the convex portions 68, respectively. The core member 62 is formed by reversing the core piece 62 of 180 ° and abutting against the core piece 62 of the other party. At this time, the clamp mounting groove 69 formed on the outer peripheral side of the semi-cylindrical portion 64 of each core piece 62 continuously extends for about 2/3 of the circumference in the circumferential direction of the core member 61. When the C-shaped clamp 70 is expanded and inserted into the spring mounting grooves 69, 69, the C-shaped clamp 70 is automatically reduced in diameter so that each core piece 62 is C-shaped. It is clamped by the clamp 70 and is firmly integrated as the core member 61.

Further, the semi-annular plate portions 65 and 66 are abutted on the core member 61 to form annular plate portions of the core member 61 on both end sides, and the shaft insertion grooves 65A and 66A are used to insert the shafts. A hole is formed.

The core member 61 is mounted on one side and the other side in the casing 1, and the magnetostrictive shaft 2 (not shown) is inserted into the shaft insertion hole formed by the shaft insertion grooves 65A and 66A to be assembled as a torque sensor. At this time, the clamp mounting groove 69 of each core piece 62 is formed shallowly from the outer surface of the core piece 62, and the C-shaped clamp 70 is made of a metal plate such as iron having magnetism. It is taken into consideration that the shape of the clamp mounting groove 69 and the C-shaped clamp 70 do not adversely affect the magnetic flux when the magnetic circuit is constituted by the magnetostrictive shaft 2 and the like.

The present embodiment has the configuration described above, and there is no particular difference in the basic operation from the prior art.

However, in the present embodiment, when the two core pieces 62, 62 are abutted in the radial direction, the concave portions 67 and the convex portions 68 provided in the abutting portions 65B, 66B are engaged with each other. Positioning is performed, and the clamp mounting grooves 69, 69 are formed on the outer peripheral surface of each core piece 62, 62 for about 2/3 of the circumference, and the clamp mounting grooves 69, 69 are arranged in the diameter reducing direction. Since the C-shaped clamp 70 that gives a spring force is expanded and inserted, the core pieces 62 are displaced in the radial direction by engaging the concave portions 67 and the convex portions 68. When the coil bobbin 8 or 9 is accommodated in the bobbin accommodating portion 63 of each core piece 62, by mounting the C-shaped clamp 70, each core piece 62 can be firmly held and integrated. Can be handled as a single part.

The core pieces 62 are strongly clamped by the C-shaped clamps 70 from both sides in the radial direction, so that a minute gap (not shown) formed between the abutting portions 64A, 65B, 66B is substantially formed. The core member 61 can be eliminated, and the magnetic resistance of the core member 61 can be minimized to be uniform.

Therefore, according to this embodiment as well, it is possible to prevent the positions of the core pieces 62 from being displaced from each other in the radial and circumferential directions and to be deformed, and the relative movement of the core pieces 62 due to the vibration of the engine or the like. Since it is possible to prevent the position from fluctuating and the magnetic resistance of the core member 61 to fluctuate, it is possible to suppress variations in torque detection characteristics among products when a magnetostrictive torque sensor is configured, It is possible to prevent erroneous detection due to vibration, and it is possible to eliminate inconvenience in handling the core member 61 during assembly.

Further, in this embodiment, since the single core piece 62 is provided with the concave portions 67, the convex portions 68, and the clamp mounting groove 69, the core member 61 is formed by only one type of core piece 62. Therefore, it is possible to prevent an increase in the number of parts of the core member and an increase in cost.

In the above embodiment, when the core pieces 62 are abutted in the radial direction, the concave portions 67 and the convex portions 68 of the abutting surfaces 65 B and 66 B are engaged with each other, and in this state C Although it has been described that the C-shaped clamp 70 is mounted, the present invention is not limited to this. For example, without using the C-shaped clamp 70, each concave portion 67 and each convex portion 68 are engaged with each other. The core pieces 62 may be integrated as the core member 61, or conversely, the core pieces 62 may be integrated only by the C-shaped clamp 70.

[0060]

[Effect of the device]

 As described above in detail, according to the present invention, the core member is composed of a pair of halves divided in the axial direction of the magnetostrictive shaft, and one of the halves has one half. A cylindrical projection protruding in the axial direction is provided at the abutment portion with the other half-divided body, and the other half-divided body is engaged with the tubular projection at the abutment portion with the one half-divided body. Since the tubular recess is provided, the tubular protrusion engages with the inside of the tubular recess to position each half body, and the core member becomes almost integral, and the abutting parts of each half body are axial. It is possible to prevent the respective halves from vibrating independently due to the deviation in the direction or the vibration of the engine or the like, and the relative positions of the halves to fluctuate, thereby changing the magnetic resistance of the core member as a whole.

Further, by using a clamp member that clamps each of the half halves from the axial direction and integrally fixes the halves, the clamp member presses the abutting portions of the half halves from both sides in the axial direction. By doing so, the gap between the abutting portions can be minimized and can be made uniform.

On the other hand, the core member is composed of a pair of halves which are divided into two in the radial direction of the magnetostrictive shaft including the annular plate portions, and the abutting portions of the halves each have an annular plate. Even if a convex portion and a concave portion are formed to be engaged with each other at the position of the portion, the respective half halves are displaced from each other in the radial direction by the positioning of the convex portion and the concave portion in engagement with each other. It is possible to prevent the deformation of the core material and the fluctuation of the magnetic characteristics.

Further, by using a clamp member that clamps each half body from the outside in the radial direction and integrally fixes it, the abutting portion of each half body is pressed by the clamp members from both sides in the radial direction. The minute gaps formed between the abutting parts can be kept to a minimum and constant, and each half-divided body is surrounded by the clamp member from the outer peripheral side so that the axial position is prevented from shifting. Therefore, the variation in the magnetic characteristics of the core member can be reduced, and the core members can be uniformly arranged.

Thus, the variation in the magnetic characteristics of the core member can be kept constant, and the stability of the magnetic characteristics against the vibration of the engine and the like can be improved, and the handling during the assembly work can be facilitated. Therefore, the reliability, stability, and assembling workability of the magnetostrictive torque sensor can be comprehensively improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a core member and the like of a magnetostrictive torque sensor according to a first embodiment of the present invention in an exploded state.

FIG. 2 is an exploded perspective view of the core member and the U-shaped clamp shown in FIG.

FIG. 3 is a longitudinal sectional view showing a core member of a magnetostrictive torque sensor according to a second embodiment of the present invention in an exploded state.

FIG. 4 is an exploded perspective view showing a core piece of a core member according to a third embodiment of the present invention.

5 is a perspective view of the core piece shown in FIG. 4. FIG.

FIG. 6 is an exploded perspective view showing a core member and a C-shaped clamp in FIG.

FIG. 7 is a vertical sectional view showing a magnetostrictive torque sensor according to a conventional technique.

8 is a partially cutaway exploded perspective view showing a core member, a coil bobbin, and the like in FIG. 7. FIG.

9 is a vertical cross-sectional view showing an enlarged main part in FIG.

FIG. 10 is a circuit diagram showing a magnetic circuit including a core member, a magnetostrictive shaft, and the like.

[Explanation of symbols]

 1 Casing 2 Magnetostrictive shaft 21,41,61 Core member 8,9 Coil bobbin 10 One side coil (excitation and detection coil) 11 Other side coil (excitation and detection coil) 22,23,42,43,62 Core piece (half-split) Body 27 Cylindrical protrusion 32 Cylindrical recess 34 C-shaped clamp (clamp member) 47 Male screw part (cylindrical protrusion) 51 Female screw part (cylindrical recess) 67 Recess 68 Convex 70 C-shaped clamp (clamp member)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuaki Kobayashi, 1671 Kasukawa-cho, Isesaki-shi, Gunma 1 1 Nippon Electric Equipment Co., Ltd. (72) Atsumi Hoshina 1671, Kasukawa-cho, Isesaki-shi, Gunma 1 Equipment Co., Ltd. (72) Inventor, Osamu Sakurai, 1671 Kasukawa-cho, Isesaki-shi, Gunma Nippon Electric Equipment Co., Ltd. (72) Inventor Hideki Ueoka 1671, Kasugawa-cho, Isesaki-shi, Gunma Japan (72) Inventor, Kazunori Chisaki, 1171-1 Kasukawa-cho, Isesaki-shi, Gunma Nippon Electric Equipment Co., Ltd.

Claims (4)

[Scope of utility model registration request] 1. A cylindrical casing, a magnetostrictive shaft rotatably disposed in the casing, a magnetostrictive shaft provided in the casing so as to surround an outer peripheral side of the magnetostrictive shaft, and an annular shape at both ends in the axial direction. A tubular core member having a plate portion formed therein, a coil bobbin provided on an inner peripheral side of the core member, and at least a coil bobbin wound around the coil bobbin in order to detect a torque acting on the magnetostrictive shaft as an electric signal. In a magnetostrictive torque sensor including a pair of exciting and detecting coils, the core member is composed of a pair of half halves that are divided into two in the axial direction of the magnetostrictive shaft, and one half of each half halves. The split body is provided with a cylindrical projection projecting in the axial direction at the abutting portion with the other half-split body, and the other half-split body is provided with the tubular projection at the position of the abutting portion with the one half-split body. A cylindrical recess that engages with And a magnetostrictive torque sensor. 2. A cylindrical casing, a magnetostrictive shaft rotatably arranged in the casing, a magnetostrictive shaft provided in the casing so as to surround an outer peripheral side of the magnetostrictive shaft, and annularly provided on both axial ends, respectively. A tubular core member having a plate portion formed therein, a coil bobbin provided on an inner peripheral side of the core member, and at least a coil bobbin wound around the coil bobbin in order to detect a torque acting on the magnetostrictive shaft as an electric signal. In a magnetostrictive torque sensor including a pair of excitation and detection coils, the core member holds a pair of half-split bodies divided in the axial direction of the magnetostrictive shaft and the half-split bodies from the axial direction. A magnetostrictive torque sensor comprising a clamp member that is integrally fixed. 3. A cylindrical casing, a magnetostrictive shaft rotatably arranged in the casing, a magnetostrictive shaft provided in the casing so as to surround an outer peripheral side of the magnetostrictive shaft, and an annular shape at both ends in the axial direction. A tubular core member having a plate portion formed therein, a coil bobbin provided on an inner peripheral side of the core member, and at least a coil bobbin wound around the coil bobbin in order to detect a torque acting on the magnetostrictive shaft as an electric signal. In a magnetostrictive torque sensor including a pair of exciting and detecting coils, the core member is composed of a pair of halves that are divided into two in the radial direction of the magnetostrictive shaft and include each annular plate portion. A magnetostrictive torque sensor characterized in that the abutting portion of the body is formed with a convex portion and a concave portion that engage with each other at the positions of the annular plate portions. 4. A cylindrical casing, a magnetostrictive shaft rotatably arranged in the casing, a magnetostrictive shaft provided in the casing so as to surround an outer peripheral side of the magnetostrictive shaft, and an annular shape at both axial ends, respectively. A tubular core member having a plate portion formed therein, a coil bobbin provided on an inner peripheral side of the core member, and at least a coil bobbin wound around the coil bobbin in order to detect a torque acting on the magnetostrictive shaft as an electric signal. In a magnetostrictive torque sensor including a pair of excitation and detection coils, the core member includes a pair of half-split bodies that are divided into two in the radial direction of the magnetostrictive shaft and include each annular plate portion, and each half-split body. A magnetostrictive torque sensor, comprising: