JP2002071479A - Torque sensor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque sensor of which quality is stable while realizing a low manufacturing cost by a simple production control. SOLUTION: A first sensor ring 2 and a second sensor ring 4 are so assembled to an input shaft 91 and an output shaft 92 that a tooth part 2a, being a first projection, and a tooth part 4a, being a second projection, face each other, in the radial direction an interval length 1 apart.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque sensor usable for electric power steering and the like, and a method for manufacturing the torque sensor.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
A torque sensor described in 146722 is known. In this torque sensor, a torsion bar 90 extends in the axial direction, and a hollow input shaft 91 as a first shaft coaxial with the torsion bar 90 is connected to a top end of the torsion bar 90 by a pin 96. I have.
A steering handle of a vehicle (not shown) is connected to an upper portion of the input shaft 91.

[0003] A second end coaxial with the torsion bar 90 and the input shaft 91 is provided at the lower end of the torsion bar 90.
A hollow output shaft 92 as a shaft is connected by spline fitting and press fitting, and a pinion 92a is integrally formed below the output shaft 92.

[0004] An outer housing 93 and an under housing 94 are provided on the outer periphery of the input shaft 91 and the output shaft 92 via bearings 95a and 95b, and mesh with a pinion 92a of the output shaft 92 in the under housing 94. The rack 81 is held. The rack 81 is provided with a motor (not shown) for assisting the steering force.

In the upper housing 93, a first sensor ring 97 as a first magnetic body made of a magnetic material is fixed to an input shaft 91. As shown in FIG. 9, the first sensor ring 97 has an annular shape extending in the circumferential direction surrounding the torsion bar 90, and the lower end surface of the first sensor ring 97 has a comb-shaped first Many rectangular teeth 97a are formed as projections.

Further, in the upper housing 93, as shown in FIG. 8, a second sensor ring 98 as a second magnetic body made of a magnetic material is fixed to the output shaft 92. As shown in FIG. 9, the second sensor ring 98 also has an annular shape extending in the circumferential direction surrounding the torsion bar 90, and the upper end surface of the second sensor ring 98 has a comb-shaped second Numerous rectangular teeth 98a are formed as projections. Each tooth 98a faces each tooth 97a with a phase shift while having a gap in the axial direction.

Further, in the upper housing 93,
As shown in FIG. 8, a coil 99 facing from the outer peripheral side is fixed to the first and second sensor rings 97 and 98. The coil 99 is connected to an interface circuit (hereinafter, referred to as an I / F circuit) 80, and the I / F circuit 80 is not shown in the drawings.
It is connected to the.

In this torque sensor, when torque is transmitted to the input shaft 91 by operating the steering wheel of the vehicle, the torsion bar 90 is twisted, causing a relative displacement between the input shaft 91 and the output shaft 92. As a result, the facing areas of the teeth 97a and 98a of the first and second sensor rings 97 and 98 change, and the inductance of the coil 99 changes. This change in inductance is input to the microcomputer via the I / F circuit 80. For this reason, in the electric power steering employing this torque sensor, the steering force according to the torque is assisted by the rack 81 by the motor.

[0009]

However, in the above-mentioned conventional torque sensor, the teeth 97a, 98a of the first and second sensor rings 97, 98 face each other in the axial direction. The length of the gap 97a, 98a tends to change. For this reason, the inductance greatly changes for each torque sensor, and the quality tends to vary.

That is, assuming that the length of the gap is 1, the magnetic permeability of air is μ ₀ , the facing area of the gap is S, and the number of turns is N, the magnetic resistance R and the inductance L of the gap are expressed by the following two equations.

[0011]

## EQU1 ## R = 1 / μ ₀ S

[0012]

L = N ² / R

Here, the first and second sensor rings 97, 98
Since the magnetic permeability of the first and second sensor rings 97 and 98 is negligible, the magnetic permeability of the first and second sensor rings 97 and 98 is negligible. Therefore, the inductance L can be expressed by the following equation.

[0014]

L = μ ₀ SN ² / l

Thus, it is understood that the inductance L is proportional to 1 / l. Therefore, for example, if the target value of the gap length 1 is 0.25 mm, a change of 0.05 mm from the target value results in the gap length 1 being 0.30 mm. , The inductance L is 20
% Will also change. Such a change in the length 1 of the gap requires that the torque sensor employs a torsion bar 90 extending in the axial direction, and that a coaxial input shaft 91 and an output shaft 92 are fixed to both ends of the torsion bar 90. Due to the nature, it may be caused by having to be assembled in the axial direction, and may also be caused by a temperature change.

For this reason, to avoid the variation in quality of each torque sensor due to this, at least the torsion bar 9 is maintained while keeping the axial length of the gap constant.
0, the input shaft 91 and the output shaft 92 must be assembled. In this case, for example, after the torsion bar 90 is spline-fitted and press-fitted to the output shaft 92, the input shaft 91 must be assembled to the torsion bar 90 from the axial direction while monitoring the axial length 1 of the gap. . When the axial length l of the gap becomes constant, a pin hole must be formed in the torsion bar 90 and the input shaft 91, and a pin 96 must be implanted. Such an operation is very troublesome.

Even if the assembly is carefully performed in this way, an error may inevitably occur in the axial length l of the gap when the pin hole is formed and when the pin 96 is implanted. Further, due to the difference in the material of the torsion bar 90 and the input shaft 91 and the output shaft 92, the axial length l of the gap is also increased by the expansion and contraction of the first and second sensor rings 97 and 98 due to a temperature change during use. Errors can occur.

As described above, in the conventional torque sensor, in order to stabilize the quality, production management is troublesome, and the production cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and it is an object of the present invention to provide a torque sensor having a stable quality while realizing a low production cost by a simple production management. It is an issue.

[0020]

A torque sensor according to the present invention comprises: a torsion bar extending in an axial direction; a first shaft connected to one end of the torsion bar and coaxial with the torsion bar; A second axis coaxial with the torsion bar and the first axis;
A first magnetic body fixed to the shaft and made of a magnetic material having a first protrusion, a second magnetic body fixed to the second shaft and made of a magnetic material having a second protrusion facing the first protrusion, A coil facing the first magnetic body and the second magnetic body, and having an inductance corresponding to a change in the facing area of the first projection and the second projection based on a torsion acting on the torsion bar; And a torque sensor that detects torque based on the inductance,

The first protrusion of the first magnetic body and the second protrusion
The magnetic member is characterized in that it faces the second protrusion in the radial direction.

In the torque sensor according to the present invention, since the first projection of the first magnetic body and the second projection of the second magnetic body face each other in the radial direction, the diameter of the gap between the first projection and the second projection at the time of assembly. There is almost no change in the length in the direction. For this reason, the inductance does not change significantly for each torque sensor, and quality variation is unlikely to occur.

Further, for example, after fixing the torsion bar to the second shaft, when the first shaft is assembled to the torsion bar from the axial direction, it is not necessary to monitor the length of the gap. And the first shaft can be fixed. Therefore, the operation becomes extremely simple.

In this way, there is almost no change in the radial length of the gap during assembly. In particular, the torsion bar and the first
Even if the shaft and the second shaft are made of different materials, since the length of the gap is in the radial direction, there is almost no error in the length due to thermal expansion due to a temperature change during use.

It is possible to adjust the zero-point output for errors in the radial length of the gap due to unavoidable errors in processing. In this case, a torque sensor with more stable quality can be obtained. Even if the zero-point output adjustment is performed in this manner, the torque sensor of the present invention has a very small zero-point output adjustment value because there is almost no error in the radial length of the gap, and the adjustment is simplified.

Therefore, the torque sensor of the present invention realizes a low production cost by simple production management,
Quality can be stabilized.

In the torque sensor according to the present invention, the first magnetic body forms a ring extending in a circumferential direction surrounding the torsion bar,
It is preferable that a comb-shaped first protrusion is formed on the outer periphery of the first magnetic body. The second magnetic body also has an annular shape extending in the circumferential direction surrounding the torsion bar.
It is preferable that a comb-shaped second protrusion is also formed on the inner periphery of the magnetic body. In this case, since the change in the facing area of the first projection and the second projection becomes large, the relative displacement between the first axis and the second axis due to the torsion of the torsion bar is reliably reflected, and the precision is high. The torque can be detected.

Further, in the torque sensor according to the present invention, one of the first magnetic body and the second magnetic body has a greater axial thickness than the other, in other words, the first magnetic body and the second magnetic body. The other is preferably thinner in the axial direction than the other. In this case, even if the relative position between the first magnetic body and the second magnetic body via the torsion bar, the first axis and the second axis is slightly shifted in the axial direction, the thickness of one magnetic body is reduced. As long as the other magnetic body is located in the middle, the facing area of the first projection and the second projection becomes constant, and stable quality can be secured.

Further, in the torque sensor of the present invention, the first
As the magnetic material, a material obtained by laminating a plurality of first punched plates obtained by punching a magnetic plate made of a magnetic material is employed, and as the second magnetic material, a plurality of second punched plates obtained by punching a similar magnetic plate are provided. It is also possible to adopt a laminated structure. As a result, the eddy current loss can be reduced, so that an accurate torque sensor can be provided. As the magnetic plate, a known silicon steel plate or the like can be used.

In the torque sensor according to the present invention, it is preferable that the holder having an annular shape and having a plurality of convex portions projecting in the axial direction is fixed to the second shaft. In this case,
The second magnetic body can be fixed to the second shaft via the holder by fitting the respective protrusions of the holder into the second notches located between the respective second protrusions. This facilitates assembling the second magnetic body and reduces an assembling error. As such a holder, it is preferable to use a holder made of a non-magnetic material so as not to damage a magnetic circuit including the first magnetic body and the second magnetic body.

[0031] The method of manufacturing a torque sensor according to the present invention comprises a torsion bar extending in the axial direction, a first shaft connected to one end of the torsion bar and coaxial with the torsion bar, and the other end of the torsion bar. A second shaft coaxial with the torsion bar and the first shaft; a first magnetic body made of a magnetic material fixed to the first shaft and having a first protrusion; and fixed to the second shaft. And a second magnetic body made of a magnetic material having a second projection facing the first projection, and a second magnetic body facing the first magnetic body and the second magnetic body and based on a twist acting on the torsion bar. A method for manufacturing a torque sensor, comprising: a coil having an inductance that changes in accordance with a change in the facing area of the one projection and the second projection, and detecting a torque based on the inductance.

The first magnetic body has an annular shape extending in the circumferential direction surrounding the torsion bar, and the first protrusion having a comb-like shape is formed on the outer periphery of the first magnetic body. The magnetic body has an annular shape extending in the circumferential direction surrounding the torsion bar, the inner circumference of the second magnetic body has a comb-like shape, and the first magnetic body has a comb-like shape.
The second projection is formed so as to face the projection in the radial direction.

A first punching step of sequentially punching out magnetic plates made of a magnetic material to obtain a plurality of first punched plates constituting the first magnetic body;

A second punching step of sequentially punching said magnetic plates to obtain a plurality of second punched plates constituting said second magnetic body;

A first laminating step of laminating the first punched plates to obtain the first magnetic body;

And a second laminating step of laminating the second punched plates to obtain the second magnetic material.

According to the method of manufacturing a torque sensor of the present invention, a first magnetic body having a ring shape extending in the circumferential direction surrounding a torsion bar and having a comb-shaped first protrusion formed on the outer periphery is obtained. Along with being able to form a ring extending in the circumferential direction surrounding the torsion bar, forming a comb-like shape on the inner circumference,
A second projection formed with a second projection radially facing the first projection;
A magnetic material can be obtained.

That is, in this manufacturing method, as a first punching step, a magnetic plate made of a magnetic material is sequentially punched to obtain a plurality of first punched plates constituting a first magnetic body. Further, as a second punching step, a similar magnetic plate is sequentially punched, whereby a plurality of second punched plates constituting the second magnetic body are obtained. Then, as a first laminating step, the first punched plates are laminated to obtain a first magnetic body. In the second laminating step, the second punched plates are laminated to obtain a second magnetic body.

At this time, the first punching plate has a first large diameter portion forming the first projection and a first small diameter portion forming the first notch located between the first large diameter portions. The second punched plate punched from the same magnetic plate as the first punched plate has a second small-diameter portion located radially outward of the first large-diameter portion and one of the second small-diameter portions. A second large-diameter portion that constitutes a second notch located on the side, and a second projection that is located on the other side of each of the second small-diameter portions, constitutes a second protrusion, and faces the first large-diameter portion in the torque sensor. It is desirable to have two middle diameter parts.

If the first and second punching plates have such a configuration, the first and second punching plates can be punched from the same magnetic plate, so that the magnetic material can be saved. Further, the first and second punching steps can be performed simultaneously or at the same time, and the first and second punching steps and the first and second laminating steps can be performed simultaneously or at the same time. Can be realized. And, from the same magnetic plate,
Two magnetic bodies can be obtained. Thus, the manufacturing cost can be reduced.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. The main mechanical configuration of the torque sensor according to the embodiment is the same as that of FIG. 8 as shown in FIGS. 1 and 2, and the same configuration as the conventional mechanical configuration shown in FIG. The same reference numerals are used, and description thereof will be omitted.

In this torque sensor, as shown in FIGS. 1 and 2, a ring 1 made of a magnetic material is fixed to an input shaft 91 in an upper housing 93, and a lower end of the ring 1 is made of a first material made of a magnetic material. A first sensor ring 2 as a magnetic body is provided.

As shown in FIG. 3, the first sensor ring 2 has an annular shape extending in the circumferential direction surrounding the torsion bar 90, and the outer peripheral surface of the first sensor ring 2 has a comb-like shape. A large number of rectangular teeth 2a are formed as the first projections. The first sensor ring 2 is formed by laminating many silicon steel plates.

As shown in FIGS. 1 and 2, a holder 3 made of a non-magnetic material is fixed to an output shaft 92 in an upper housing 93, and a second magnetic body made of a magnetic material is provided above the holder 3. The second sensor ring 4 is provided.

As shown in FIG. 3, the second sensor ring 4 also has an annular shape extending in the circumferential direction surrounding the torsion bar 90, and the inner peripheral surface of the second sensor ring 4 has a comb-like shape. A large number of rectangular teeth 4a are formed as second projections. The second sensor ring 4 is also formed by laminating many silicon steel plates. Each tooth portion 4a of the second sensor ring 4 faces each tooth portion 2a of the first sensor ring 2 while having a gap length 1 in the radial direction. The first sensor ring 2 is thicker in the axial direction than the second sensor ring 4.

As shown in FIG. 4, the holder 3 has an annular shape and has a plurality of projections 3a projecting in the axial direction. The second sensor ring 4 is fixed to the output shaft 92 via the holder 3 by fitting the respective protrusions 3a of the holder 3 into the second cutouts 4b located between the respective teeth 4a.

Further, as shown in FIGS. 1 and 2, a guide sensor 5 made of a magnetic material is fixed in the upper housing 93 by a circlip 6. The guide sensor 5 also has a torsion bar 9 as shown in FIG.
The second sensor ring 4 has an annular shape extending in the circumferential direction surrounding the second sensor ring 4.

As shown in FIGS. 1 and 2, a magnetic circuit is constituted by the ring 1, the first sensor ring 2, the second sensor ring 4, and the guide sensor 5, and the coil 7 is disposed in the magnetic circuit. ing.

The torque sensor of the embodiment configured as described above is manufactured as follows.

First, the first sensor ring 2 and the second sensor ring 4 are manufactured as follows. First, as shown in FIG. 5, a silicon steel sheet W is prepared, and this silicon steel sheet W is punched by a die 20 and a punch 21. As a result, FIG.
As shown in FIG. 1, a first having a plurality of first large diameter portions 12a and a first small diameter portion 12b located between the first large diameter portions 12a.
A blank 12 is obtained. Also, the same number of second small diameter portions 14c as the first large diameter portion 12a, the second large diameter portions 14b located on the right side of each second small diameter portion 14c, and the punching located on the left side of each second small diameter portion 14c. A second punched plate 14 having a second middle diameter portion 14a having a diameter D3 is obtained.

At this time, the first punched plate 12 located inside from the silicon steel plate W and the second punched plate 14 located outside are co-produced (first and second punching steps). Here, as shown in FIGS. 5 and 7, the outer diameter of the punch 21 is usually made about 30 μm smaller than the inner diameter of the die 20, and the silicon steel sheet W has an overlap m between the punch 21 and the die 20. Will be cut off. Therefore, as shown in FIG. 6, the first large-diameter portion 12a of the first punching plate 12 and the second small-diameter of the second punching plate 14 which are co-produced by the punch 21 and the die 20 at the punching diameter D2. It cannot be inserted facing part 14c.

Therefore, in the torque sensor of the embodiment,
As shown in FIG. 3, the first punched plate 12 and the second punched plate 14 cooperate with each other, and as shown in FIG.
Second protrusion 4a composed of protrusion 2a and second middle diameter portion 14a
And so that they face each other.

That is, as shown in FIG.
Is used to punch out the disc-shaped discard member 15. Thereafter, a plurality of discarding members 16 constituting the first small diameter portion 12b, the second medium diameter portion 14a, and the second large diameter portion 14b are punched. Then, the first punching plate 12 is punched while ensuring the accuracy of the punching diameter D2. Finally, the second punching plate 14 is punched with a punching diameter D4. Thus, the first punched plate 12 and the second punched plate 14 are laminated while being punched (first and second laminating steps). When laminating, silicon steel sheet W
A plurality of first punched plates 12 using dowels formed in advance
To obtain the first sensor ring 2. Similarly,
A plurality of second punching plates 14 are fixed using a dowel,
The sensor ring 4 is obtained.

In the embodiment, the punch 2 having the punching diameter D2 is used.
1 was set to 28 mm, and the inner diameter of the die 20 was set to 28.03.
mm. Further, the outer diameter of the punch 21 having the punching diameter D3 is set to 28.53 mm, and the inner diameter of the die 20 is set to 28.56 m.
m. As a result, the outer diameter of the first projection 2a formed by the first large-diameter portions 12a of the plurality of first punched plates 12 becomes 2
8.03 mm, and the inner diameter of the second protrusion 4a formed by the second middle diameter portions 14a of the plurality of second punched plates 14 is 28.5.
Since it is 3 mm, the length l of the gap is 0.25 mm.

Then, the first sensor ring 2 and the second
The torque sensor is assembled using the sensor ring 4. First, as shown in FIG. 1 and FIG.
2 and the second sensor ring 4 is pressed into the holder 3.
To fit. Then, the torsion bar 90 is fixed to the output shaft 92.

On the other hand, after the upper housing 93 is fixed to the input shaft 91 via the bearing 95a, the guide sensor 5 is fixed to the upper housing 93 by the circlip 6. Then, the coil 7 is inserted into the guide sensor 5. After the ring 1 is press-fitted into the input shaft 91, the first sensor ring 2 is press-fitted.

Then, the input shaft 91 is inserted from the axial direction of the torsion bar 90, and the input shaft 91 and the torsion bar 90 are connected by the pin 96. Thus, the torque sensor according to the embodiment is manufactured.

In this torque sensor, when torque is transmitted to the input shaft 91 by operating the steering wheel of the vehicle, the torsion bar 90 is twisted, causing a relative displacement between the input shaft 91 and the output shaft 92. Thereby, the tooth portions 2 of the first and second sensor rings 2 and 4
The facing areas a and 4a change, and the inductance of the coil 7 changes. This change in inductance is input to the microcomputer via an I / F circuit (not shown).

In particular, in this torque sensor, both the first sensor ring 2 and the second sensor ring 4 form a ring extending in the circumferential direction surrounding the torsion bar 90, and have facing tooth portions 2a, 4a. As a result, the change in the facing area of the teeth 2a, 4a becomes large, so that the input shaft 91 and the output shaft 9 due to the torsion of the torsion bar 90 are twisted.
2 is reliably reflected, and the torque can be detected with high accuracy.

In this torque sensor, the first sensor ring 2 and the second sensor ring 4 are formed by laminating a large number of silicon steel plates W. Accordingly, assuming that the total thickness of the silicon steel sheet W in the vertical direction with respect to the magnetic flux is T, and the thickness of one sheet in the vertical direction with respect to the magnetic flux when the silicon steel sheets W are stacked is t, the thickness T is Since the thickness t is much smaller, the eddy current loss can be reduced and the precision is high.

Thus, in the electric power steering employing this torque sensor, the steering force according to the torque is assisted by the rack 81 by the motor.

At this time, in this torque sensor, the teeth 2a of the first sensor ring 2 and the teeth 4a of the second sensor ring 4
Face each other in the radial direction, so that the length l of the radial gap between the teeth 2a and the teeth 4a hardly changes during assembly. Further, even if eccentricity occurs due to an assembling error or the like, and the length l of the gap in one part decreases, the length l of the gap increases on the opposite side in the radial direction. Almost no change. For this reason, the inductance does not change significantly for each torque sensor, and quality variation is unlikely to occur.

In this torque sensor, after fixing the torsion bar 90 to the output shaft 92, when the input shaft 91 is assembled to the torsion bar 90 from the axial direction, it is almost unnecessary to monitor the length l of the gap. In this state, the torsion bar 90 and the input shaft 91
And can be fixed. Therefore, the operation becomes extremely simple.

Thus, in this torque sensor, the length l of the gap hardly changes during assembly. In particular, the torsion bar 90, the input shaft 91 and the output shaft 9
Even if the material is different between the two, there is almost no error in the length due to the thermal expansion accompanying the temperature change during use because the length l of the gap is in the radial direction. Note that it is possible to perform zero point output adjustment for an error in the gap length 1 due to an unavoidable error in processing. In this case, a torque sensor with more stable quality can be obtained. Even if the zero point output adjustment is performed in this manner, in the torque sensor of the embodiment, since there is almost no error in the gap length l,
The zero point output adjustment value is extremely small, and such adjustment is simplified.

In this torque sensor, the first sensor ring 2 is thicker in the axial direction than the second sensor ring 4, so that the relative position between the first sensor ring 2 and the second sensor ring 4 is increased. Even if it is slightly displaced in the axial direction,
As long as the second sensor ring 4 is positioned within the thickness of the first sensor ring 2, the facing areas of the first sensor ring 2 and the second sensor ring 4 become constant, and stable quality can be secured.

Further, in this torque sensor, the second sensor ring 4 is fitted to the output shaft 92 by fitting the projection 3a of the holder 3 fixed to the output shaft 92 into the second notch 4b of the second sensor ring 4. Since the second sensor ring 4 is fixed, it is easy to assemble the second sensor ring 4 and the assembling error can be reduced.

Therefore, according to the torque sensor and the method of manufacturing the same according to the embodiment, the quality can be stabilized while realizing a low production cost by simple production management.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a torque sensor according to an embodiment.

FIG. 2 is an enlarged cross-sectional view of the torque sensor according to the embodiment.

FIG. 3 relates to a torque sensor according to an embodiment, and FIGS.
FIG. 3 is a sectional view taken along line III-III of FIG.

FIG. 4 relates to a torque sensor according to the embodiment, in which a holder and a second
It is a perspective view which shows the assembly state with a sensor ring.

FIG. 5 is a longitudinal sectional view of a die and a punch in the method of manufacturing the torque sensor according to the embodiment.

FIG. 6 is a plan view of a first punched plate and a second punched plate according to the torque sensor of the embodiment.

FIG. 7 is an enlarged cross-sectional view of a die and a punch in the method of manufacturing the torque sensor according to the embodiment.

FIG. 8 is a longitudinal sectional view of a conventional torque sensor.

FIG. 9 is an enlarged sectional view of a conventional torque sensor.

[Explanation of symbols]

 90 ... torsion bar 91 ... 1st axis (input shaft) 92 ... 2nd axis (output shaft) 2 ... 1st magnetic body (1st sensor ring) 4 ... 2nd magnetic body (2nd sensor ring) 2a ... tooth part (1st projection) 4a ... tooth part (2nd projection) 4b ... 2nd notch 3a ... convex part 7 ... coil 12 ... 1st punching plate 14 ... 2nd punching plate 12a ... 1st large diameter part 12b ... 1st 1 small diameter portion 14a: second medium diameter portion 14b: second large diameter portion 14c: second small diameter portion

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshiyuki Shibata 1-1, Asahi-cho, Kariya-shi, Aichi F-term (reference) 2F051 AA01 AB05 BA03 3D033 CA02 CA16 CA28

Claims (7)

[Claims] A torsion bar extending in the axial direction, a first shaft connected to one end of the torsion bar and coaxial with the torsion bar, and a first shaft connected to the other end of the torsion bar; A second axis coaxial with the first axis, a first magnetic body fixed to the first axis and made of a magnetic material having a first projection, and fixed to the second axis and facing the first projection; A second magnetic body made of a magnetic material having a second protrusion, and the first protrusion and the second protrusion facing the first magnetic body and the second magnetic body and being torsionally acting on the torsion bar. A torque sensor having a coil whose inductance changes in response to a change in facing area, and detecting a torque based on the inductance, wherein the first protrusion of the first magnetic body and the first protrusion of the second magnetic body The two protrusions must face each other in the radial direction. And a torque sensor. 2. The first magnetic body has a ring shape extending in a circumferential direction surrounding the torsion bar, and a first protrusion having a comb-like shape is formed on an outer periphery of the first magnetic body. 2. The device according to claim 1, wherein the second magnetic body has a comb-shaped second projection formed on an inner periphery of the second magnetic body. Torque sensor. 3. The torque sensor according to claim 1, wherein one of the first magnetic body and the second magnetic body has a greater axial thickness than the other. 4. The first magnetic body includes a plurality of first punched plates obtained by punching a magnetic plate made of a magnetic material, and the second magnetic body includes a plurality of second punched plates obtained by punching the magnetic plate. The torque sensor according to any one of claims 1 to 3, wherein a plurality of the torque sensors are stacked. 5. A second shaft is fixed to a holder having an annular shape and having a plurality of projections projecting in the axial direction, and a second magnetic body is provided in a second notch located between the second projections. The torque sensor according to claim 1, wherein the torque sensor is fixed to the second shaft via the holder by fitting a convex portion. 6. A torsion bar extending in the axial direction, a first shaft connected to one end of the torsion bar and coaxial with the torsion bar, and a first shaft connected to the other end of the torsion bar. A second axis coaxial with the first axis, a first magnetic body fixed to the first axis and made of a magnetic material having a first projection, and fixed to the second axis and facing the first projection; A second magnetic body made of a magnetic material having a second protrusion, and the first protrusion and the second protrusion facing the first magnetic body and the second magnetic body and being torsionally acting on the torsion bar. A coil having an inductance that changes in accordance with a change in the facing area, wherein the first magnetic body extends in a circumferential direction surrounding the torsion bar. Form a ring that is The first protrusion having a comb-like shape is formed on an outer periphery of one magnetic body, and the second magnetic body has an annular shape extending in a circumferential direction surrounding the torsion bar, and an inner periphery of the second magnetic body. Is formed with a comb-like shape, and the second protrusion is formed to face the first protrusion in the radial direction. A plurality of first magnetic members are formed by punching out magnetic plates made of a magnetic material sequentially. A first punching step of obtaining a first punched plate constituting: and a second punching step of sequentially punching out the magnetic plate to obtain a second punched plate constituting a plurality of the second magnetic bodies. A first laminating step of laminating the first punched plate to obtain the first magnetic body, and a second laminating step of laminating each second punched plate to obtain the second magnetic body. A method for manufacturing a torque sensor. 7. A first punched plate has a first large diameter portion forming a first projection, and a first small diameter portion forming a first notch located between each of the first large diameter portions. A second punched plate punched from the same magnetic plate as the first punched plate includes a second small-diameter portion located radially outward of the first large-diameter portion, and one side of each of the second small-diameter portions. A second large-diameter portion forming a second notch located on the other side of each of the second small-diameter portions,
7. The method according to claim 6, wherein the second projection is formed, and the torque sensor has the first large diameter portion and a second medium diameter portion facing the first large diameter portion.