JPH0617059Y2 - Torque sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a torque sensor suitable for being applied to, for example, an electric power steering device of an automobile.

[Conventional technology]

An electric power steering device is being developed as a power steering device for assisting a force for operating a steering wheel of an automobile. This has a structure in which the torque applied to the steered wheels is detected and the electric motor provided in the steering mechanism is rotated according to the detected torque.

By the way, as the torque detecting means, for example, a torque sensor shown in FIG. 8 has been proposed (Japanese Utility Model Application No. 63-54841).
issue). FIG. 8 is a half cross-sectional view showing the structure of the torque sensor, in which an upper shaft 1a having steering wheels (not shown) mounted thereon and a lower shaft 1c having a steering mechanism (not shown) coaxially mounted thereto via a torsion bar 1b. Are connected together, the upper shaft
1a is rotatably supported via a bearing 3 in a cylindrical case 2 fixedly attached to a vehicle body (not shown).

A first sleeve 4a made of a non-magnetic material is externally fitted and fixed to the lower end portion (left side in the drawing) of the upper shaft 1a, and first and second cylinders 5 and 6 made of a magnetic material are externally fitted and fixed to the outer circumference thereof. There is. A narrow ring-shaped gap forming member 20 made of a non-magnetic material, such as brass, aluminum or austenitic stainless steel, is interposed between the first and second cylinders 5 and 6 to form a first gap. It is externally fitted and fixed to the outer circumference of the sleeve 4a.

The upper shaft end face of the first cylinder 5 is a plane perpendicular to the shaft center of the upper shaft 1a, and the lower shaft end face has a large number of rectangular tooth portions 5a, 5a ... Formed at equal pitches in the circumferential direction. It is provided. Each tip of these tooth portions 5a, 5a ... Is a surface perpendicular to the axis of the upper shaft 1a.

On both axial end faces of the second cylinder 6, tooth portions 6a, 6a ... And tooth portions 6b, 6b ... Which are formed in the same shape and at the same pitch as the tooth portions 5a, 5a.
And tooth portions 6a and 6b are aligned on the same line parallel to the axis of the cylinder 6. And tooth 6a and tooth
The cylinders 5 and 6 are positioned so as to face each other at a half of the tooth width of each of the tooth portions 6a and 5a when the torque is not acting on the torsion bar 1b.

A second sleeve made of a non-magnetic material is provided on the upper end of the lower shaft 1c.
4b is externally fitted and fixed, and a third cylinder 7 made of a magnetic material is externally fitted and fixed to the outer periphery thereof. The cylinder 7 has the same shape as the cylinder 5, and is attached with the vertical direction opposite to the cylinder 5.

Therefore, the tooth portions 6b, 6b ... Of the second cylinder 6 and the tooth portions 7a, 7a ... Of the third cylinder 7 are opposed to each other with a proper distance. When no torque acts on the torsion bar 1b between the tooth portions 6b and 7a, the tooth portions 6b and 7a are in the same facing state as the tooth portions 6a and 5a. The cylinders 6 and 7 are positioned so as to face each other at a half of the width. On the outer peripheral surface of the lower end portion of the upper shaft 1a, a narrow strip-shaped stopper 8 parallel to the shaft center is provided. On the other hand, a stopper guide groove 9 having a proper length in the circumferential direction is formed on the inner peripheral surface of the opening opened concentrically with the axis at the upper end of the lower shaft 1c.

The stopper 8 is fitted in the stopper guide groove 9, and the arc of the stopper guide groove 9 is arranged so that the upper and lower shafts 1a, 1c can relatively rotate, for example, by about half of the tooth width of the tooth portion 6a. The strip length is selected.

Inside the case 2, cylindrical bodies 10A and 10B made of a magnetic material and having a circumferential groove are internally fixed. The cylindrical body 10A is arranged so as to face the facing portions of the first and second cylinders 5 and 6, and the cylindrical body 10B is arranged so as to face the facing portions of the second and third cylinders 6 and 7. I have set up. And these cylinders 10A, 10B
The first electromagnetically coupled detection coil 11 and the second electromagnetically coupled detection coil 12 are wound around the circumferential grooves of the first and second electromagnetically coupled detection coils, respectively.
The electromagnetically coupled detection coil 11 is electromagnetically coupled to the cylinders 5 and 6, and the second electromagnetically coupled detection coil 12 is electromagnetically coupled to the cylinders 6 and 7, respectively.

In this way, by making the shapes of the shaft end surfaces of the cylinders 5 and 6 facing each other and the shape of the shaft end surfaces of the cylinders 6 and 7 the same, when the ambient temperature changes, the electromagnetic coupling of the cylinders 5 and 6 The state and the electromagnetically coupled state of the cylinders 6 and 7 are similarly changed and do not differ, and the temperature is properly compensated so that no error occurs in the output torque.

On the other hand, in this torque sensor, when the cylinder 5 is positioned, first, the cylinders 6 and 7 are made to face each other with a gap equal to the width dimension of the gap forming member 20, so that the voltage induced in the electromagnetic coupling detection coil 12 becomes zero, for example. The first sleeve 4a,
The second sleeve 4b is fixed with an adhesive, for example. After that,
The cylinder 5 is rotated while pressing the cylinder 5 against the cylinder 6 via the gap forming body 20, and at the position where the voltage induced in the electromagnetic coupling detection coil 11 becomes zero similarly to the above, the first sleeve 4a is bonded to the first sleeve 4a with an adhesive, for example. Stick to it. This makes it possible to obtain the electromagnetically coupled state of the cylinders 5 and 6 which is equal to the electromagnetically coupled state of the cylinders 6 and 7.

The gap forming body 20 is a non-magnetic body and has no adverse effect on the magnetic coupling between the cylinders 5 and 6.

Then, the difference between the induced voltages of the first and second electromagnetically coupled detection coils 11 and 12 is obtained by, for example, a differential amplifier, so that the induced voltages of both electromagnetically coupled detection coils 11 and 12 are canceled by the ambient temperature change, and The electromagnetic coupling state corresponding to the relative rotation amount of 6 and 7 is detected, and the torque acting on the torsion bar 1b is always detected properly.

[Problems to be solved by the device]

However, in the torque sensor having the above configuration,
The first cylinder 5 can be positioned in the axial direction by the gap forming member 20 interposed between the second cylinders 5 and 6, but the second cylinder 6 and the third cylinder 7 are electromagnetically coupled to each other. In order to obtain the same electromagnetically coupled state of the first cylinder 5 and the second cylinder 6, the cylinder 5 is pressed against the cylinder 6 through the gap forming body 20 and the cylinder 5 is adjusted while rotating to form the cylinder 5. First sleeve
There was a problem that it required a troublesome work such as sticking to 4a.

The present invention has been made in view of the above problems,
A first cylinder fixed to one of two shafts connected via a torsion bar, and a second cylinder adjacent to the first cylinder.
Positioning of the first cylinder or the second cylinder in the rotational direction is simplified by disposing a washer having locking tongues that are respectively engaged with the gaps of the tooth portions of each cylinder between the first cylinder and the second cylinder. It is an object of the present invention to provide a torque sensor that can be used for various purposes.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a first cylinder attached to one of two shafts connected through a torsion bar, and a third cylinder attached to the other shaft.
A first cylinder and a third cylinder, and one or two second cylinders attached to the one shaft, the first cylinder and the second cylinder being disposed between the first cylinder and the third cylinder. Tooth portions are formed on the shaft end surfaces on the opposite side and on the shaft end surfaces on the opposite side of the third cylinder and the second cylinder, respectively, and the first cylinder and the second cylinder are formed.
Of the first cylinder, the torque sensor comprising: an electromagnetically coupled detection coil electromagnetically coupled to the cylinder; and an electromagnetically coupled detection coil electromagnetically coupled to the third cylinder and the second cylinder. And a second cylinder, a washer having locking tongues, which are engaged in the gaps between the teeth of the cylinders, is arranged.

[Action]

According to the present invention, with the above-described configuration, the first cylinder or the second cylinder is provided between the first cylinder and the second cylinder with the washers having the locking tongues inserted in the gaps between the teeth of the respective cylinders. Two cylinders are rotationally positioned.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings showing an embodiment thereof.

FIG. 1 is a half sectional view showing a structure of a torque sensor according to the present invention. Upper shaft 1a with steering wheel (not shown)
And a lower shaft 1c to which a steering mechanism (not shown) is attached are coaxially connected via a torsion bar 1b,
The upper shaft 1a is rotatably supported via a bearing 3 in a cylindrical case 2 fixedly attached to a vehicle body (not shown).

A first sleeve 4a made of a non-magnetic material is externally fitted and fixed to the lower end portion (left side in the drawing) of the upper shaft 1a, and first and second cylinders 5 and 6 made of a magnetic material are externally fitted and fixed to the outer circumference thereof. There is.

The upper shaft end face of the first cylinder 5 is a plane perpendicular to the shaft center of the upper shaft 1a, and the lower shaft end face has a large number of rectangular tooth portions 5a, 5a ... Formed at equal pitches in the circumferential direction. It is provided. Each tip of these tooth portions 5a, 5a ... Is a surface perpendicular to the axis of the upper shaft 1a.

On both axial end faces of the second cylinder 6, tooth portions 6a, 6a ... And tooth portions 6b, 6b ... Which are formed in the same shape and at the same pitch as the tooth portions 5a, 5a.
And tooth portions 6a and 6b are aligned on the same line parallel to the axis of the cylinder 6. And tooth 6a and tooth
The cylinders 5 and 6 are positioned so as to face each other at a half of the tooth width of each of the tooth portions 6a and 5a when the torque is not acting on the torsion bar 1b.

A second sleeve made of a non-magnetic material is provided on the upper end of the lower shaft 1c.
4b is externally fitted and fixed, and a third cylinder 7 made of a magnetic material is externally fitted and fixed to the outer periphery thereof. The cylinder 7 has the same shape as the cylinder 5, and is attached with the vertical direction opposite to the cylinder 5.

Therefore, the tooth portions 6b, 6b, ... Of the second cylinder 6 and the tooth portions 7a, 7a, ... Of the third cylinder 7 face each other with a proper distance. Also tooth 6
When the torque is not acting on the torsion bar 1b between the b and the tooth portion 7a, the tooth portion 6a and the tooth portion 7a are half of the tooth width in the same facing state as the tooth portions 6a and 5a. The cylinders 6 and 7 are positioned so as to face each other. First,
The tooth portions 5a, 6a, 6b, 7a of the second and third cylinders 5, 6, 7 each have eight teeth, and the gaps between the tooth portions are also eight.

On the outer peripheral surface of the lower end portion of the upper shaft 1a, a narrow strip-shaped stopper 8 parallel to the shaft center is provided. On the other hand, lower shaft 1c
On the inner peripheral surface of the opening opened concentrically with the axis at the upper end of
A stopper guide groove 9 having a proper length and a notch is formed in the circumferential direction.

The stopper 8 is engaged in the stopper guide groove 9, and the upper and lower shafts 1a, 1c have an arc shape of the stopper guide groove 9 so that the upper and lower shafts 1a, 1c can rotate relative to each other, for example, by approximately half the tooth width of the tooth portion 6a. The length is selected.

Inside the case 2, cylindrical bodies 10A and 10B made of a magnetic material and having a circumferential groove are internally fixed. The cylindrical body 10A is arranged so as to face the facing portions of the first and second cylinders 5 and 6, and the cylindrical body 10B is arranged so as to face the facing portions of the second and third cylinders 6 and 7. I have set up. And these cylinders 10A, 10B
The first electromagnetically coupled detection coil 11 and the second electromagnetically coupled detection coil 12 are wound around the circumferential grooves of the first and second electromagnetically coupled detection coils, respectively.
The electromagnetically coupled detection coil 11 is electromagnetically coupled to the cylinders 5 and 6, and the second electromagnetically coupled detection coil 12 is electromagnetically coupled to the cylinders 6 and 7, respectively.

Further, in the present invention, between the first cylinder 5 and the second cylinder 6, a plurality of locking members that are respectively engaged in the gaps between the tooth portions 5a, 6a of the cylinders 5, 6 are provided. Washer 3 with tongues 30a, 30a ...
It is externally fitted and fixed to the outer periphery of the first sleeve 4a with 0 interposed. That is, as shown in FIGS. 3 to 5, the washer 30 has a substantially ring shape, and each tooth portion 5 of the first and second cylinders 5 and 6 is formed.
According to the number of gaps (a, 6a) (8 places), divide the outer peripheral edge into 12 equal parts and make notches in the equal parts, and one part between the notches is bent to one side and protrudes, It has a width dimension almost the same as the width dimension of the gap between the tooth portions 5a, 5a, and the length is 5
The width dimension of the gap between the teeth 6a, 6a is formed by forming on the locking tongue 30a shorter than the depth dimension of the gap between a and 5a, bending the part between the notches adjacent to this to the other side, and projecting. Is formed on the locking tongue 30a that has almost the same width dimension as that of the tooth and is shorter than the depth dimension of the gap between the teeth 6a, 6a, and locks between the notch on the side opposite to this in the circumferential direction. The tongue pieces are not provided, and the engaging tongue pieces 30a, 30a and the portions not provided with the engaging tongue pieces are formed alternately in the outer circumferential direction in a shape cut off by the engaging tongue pieces. There is.

One of the locking tongues 30a, 30a of the washer 30 has a protruding locking tongue 30a inserted into the gap between the tooth portions 5a, 5a of the first cylinder 5 and projected to the other side. The locking tongue piece 30a is engaged with the gap between the tooth portions 6a, 6a ... Of the second cylinder 6. The tooth portions 5a, 6a of the first cylinder 5 and the second cylinder 6 are at positions displaced by 30 ° in the circumferential direction.

In this manner, the locking tongue pieces 30a, 3 are arranged between the first cylinder 5 and the second cylinder 6 and are arranged in the gaps between the tooth portions 5a, 6a of the respective cylinders 5, 6.
The first cylinder 5 and the second cylinder 6 are axially and rotationally positioned by the washers 30 into which 0a ... The second cylinder 6 is fixed to the upper shaft 1a, the first cylinder is rotationally positioned by the washer 30, and then fixed to the upper shaft 1a with an adhesive or a fixing pin. It

By doing the above, it is possible to easily obtain the electromagnetic coupling state of the cylinders 5 and 6, which is equal to the electromagnetic coupling state of the cylinders 6 and 7. Then, the cylinder 5 is positioned in the rotational direction, the time required for the positioning can be greatly reduced, and the operation is not bothersome.

The washer 30 is a non-magnetic material and does not adversely affect the magnetic coupling between the cylinders 5 and 6.

Then, the difference between the induced voltages of the first and second electromagnetically coupled detection coils 11 and 12 is obtained by, for example, a differential amplifier, so that the induced voltages of both electromagnetically coupled detection coils 11 and 12 are canceled by the change of the surrounding hot spring, and The electromagnetic coupling state corresponding to the relative rotation amount of 6 and 7 is detected, and the torque acting on the torsion bar 1b is always detected as appropriate.

FIG. 6 shows another embodiment of the torque sensor according to the present invention, in which the second cylinder is replaced by two cylinders instead of two cylinders.
One cylinder 6A is provided with two cylinders 6A and 6B, and a tooth portion 6a opposite to the tooth portion 5a of the first cylinder 5 is formed on the upper shaft end surface of one cylinder 6A of the cylinders 6A and 6B, while the other cylinder 6B is underside. A tooth portion 6b facing the tooth portion 7a of the third cylinder 7 is provided on the shaft end surface. Then, a washer 40 made of a non-magnetic material, which will be described later, is provided between the second two cylinders 6A and 6B.
Is intervened. Further, a washer having locking tongue pieces 30a, 30a, which are respectively engaged with the gaps between the tooth portions 5a, 6a of the respective cylinders 5, 6A, between the first cylinder and the second one cylinder 6A. 30 are arranged.

Then, the washer 30 positions the first cylinder 5 in the rotational direction.

Further, key grooves 6c, 6c, 6d, 6d are bored in the second two cylinders 6A, 6B, respectively, at positions facing each other in the radial direction on the facing end faces thereof. On the other hand, the washer 40 is a tongue piece for locking that protrudes from the inner peripheral edge to one side at two opposing locations in four radial divisions.
40a, 40a are provided, and locking tongues 40b, 40b projecting from the inner peripheral edge to the other side are formed at two opposite locations on the other side. Each of the locking tongue pieces 40a, 40a, 40b, 40b is provided with a notch concave portion at a central portion in the width direction from the outer edge toward the depth direction.

Then, the key grooves 6c, 6c, 6 of the second two cylinders 6A, 6B are formed.
Tongues 40a, 40a, 40b, 40b for locking the washer 40 are inserted into the d, 6d by press fitting. The washer 40 positions the two second cylinders 6A and 6B in the axial and rotational directions.

In the present embodiment, the second cylinder is composed of two cylinders 6A and 6B, and the cylinders are provided at four positions,
All four cylinders 5, 6A, 6B, 7 can be made into the same shape, which simplifies the manufacture, and the four cylinders 5, 6A, 6B, 7
Two cylinders 5 and 6A that are adjacent to each other on both sides
6B and 6B form independent magnetic circuits, respectively, and there is an advantage that one magnetic circuit does not magnetically affect the other magnetic circuit and the performance is stable.

In the above embodiment, the second cylinder 6 is the upper shaft 1a.
The first cylinder 5 is fixed to the second shaft 6 by the washer 30 in the rotational direction, but the first cylinder 5 is fixed to the upper shaft 1a. The second cylinder 6 can be rotationally positioned with respect to the first cylinder 5 by a washer 30.

[Effect of device]

According to the present invention, as described above, the washer having the locking tongues, which are engaged in the gaps between the teeth of the respective cylinders, is arranged between the cylinder on the one side and the cylinder on the center side. By the first
It is possible to easily position the cylinder or the second cylinder in the rotation direction.

[Brief description of drawings]

FIG. 1 is a half sectional view showing a structure of an embodiment of a torque sensor according to the present invention, FIG. 2 is a schematic perspective view of a main part thereof, and FIG.
The figure shows the front view of the washer used for the torque sensor, No. 4
FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, FIG. 5 is a perspective view of the washer, FIG. 6 is a schematic perspective view of a main part of a torque sensor according to another embodiment of the present invention, and FIG. FIG. 8 is a perspective view of a washer used for the torque sensor, and FIG. 8 is a half sectional view of a conventional torque sensor. 1a ... upper shaft, 1b ... torsion bar, 1c ... lower shaft, 5,
6, 6A, 6B, 7 ... Cylindrical, 5a, 6a, 6b, 7a ... Tooth, 11, 12 ... Electromagnetic coupling detection coil, 30 ... Washer, 30a ... Locking tongue piece

Claims (1)

[Scope of utility model registration request] 1. A first cylinder attached to one of the two shafts connected via a torsion bar, a third cylinder attached to the other shaft, the first cylinder and the third cylinder. A first cylinder and a second cylinder disposed between the first cylinder and the second cylinder, the first cylinder and the second cylinder being attached to the one shaft.
Of the first cylinder and the second cylinder, and tooth portions are formed on the shaft end surface of the opposite side of the cylinder and the shaft end surface of the opposite side of the third cylinder and the second cylinder, respectively. A torque sensor comprising: an electromagnetically coupled detection coil that is electromagnetically coupled; and an electromagnetically coupled detection coil that is electromagnetically coupled to the third cylinder and the second cylinder. A torque sensor, characterized in that a washer having locking tongues, which are respectively engaged in the gaps between the tooth portions of each cylinder, is arranged between the cylinder and the cylinder.