JPH08136365A - Torque sensor - Google Patents

Abstract

PURPOSE: To prevent a winding and a lead wire from being damaged and improve the reliability of a sensor, by soldering and connecting within a narrow groove defined between flanges an end part of a sensor coil (winding) and a cable (lead wire) connected to a detection circuit part. CONSTITUTION: An end part of a sensor coil (winding) 71 wound around a wide groove 75 defined between flange parts 65 and 69 of a bobbin 62 is guided through a notch part formed in the flange part 69 into a groove 68, and twined with a cable (lead wire) 21 connected to a connector 72 of the torque sensor within the groove 68 and, soldered and connected each other. In this state, an adhesive is filled in the groove 68, so that the coil 71 and the cable 21 are fixed together with a connecting part 70 therebetween in the groove 68. Since the coil 71 is connected to the cable 21 by the soldering within the groove 68 separated from the groove 75 where the coil 71 is wound, the coil 71 is prevented from being damaged by the soldering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a torque sensor used in an electric power steering apparatus mounted on a vehicle or the like to assist steering operation and reduce the force required for steering.

[0002]

2. Description of the Related Art As an electric power steering device for a vehicle or the like, the rotational output of an electric motor, which is an auxiliary steering torque, is reduced by a gear device and transmitted to an output shaft of a steering mechanism to assist the steering force applied to a steering wheel. Then, there is known one configured to steer the wheels.
In such an electric power steering device,
A torque sensor for detecting the steering force transmitted to the input shaft, that is, the torque is provided, and the electric motor is driven according to the detection result of the torque sensor to generate the auxiliary steering force.

As such a torque sensor, for example,
There is a torque sensor as described in Japanese Utility Model Laid-Open No. 1-142831 and Japanese Utility Model Laid-Open No. 4-47638. In the torque sensor disclosed in this prior art, the lead wire connected to the detection circuit portion and the coil winding are soldered at a predetermined position of the coil winding wound on the bobbin. Further, the flanges at both ends of the bobbin have the same diameter.

[0004]

However, this conventional technique has the following problems.

First, during the soldering work of the winding wire and the lead wire, the winding part wound on the bobbin may be damaged by the soldering part itself, which may cause a short circuit or disconnection of the coil. In this case, the reliability of the sensor cannot be obtained.

Further, there has been a demand that the axial dimension must be made compact in view of the column layout and the problem that the sensor output characteristics change when the shape is largely changed in the slider movement direction.

The object of the present invention is to improve the reliability as a sensor without damaging the winding and the lead wire by the soldering work, and to change the coil winding size in the slider moving direction. It is to provide a torque sensor that can realize the same output performance with a bobbin size.

[0008]

In order to achieve the above object, a torque sensor of the present invention converts a twist of a shaft into a moving amount of a slider member, and detects the moving amount of the slider member as a self-inductance change of a detecting coil portion. In the torque sensor described above, the detection coil portion is formed of a bobbin around which a coil is wound, and the bobbin has a cylindrical portion and annular flange portions provided at both axial ends of the cylindrical portion, and one of the flange portions is provided. A diameter of the torque sensor is larger than that of the other diameter.

[0009]

According to the torque sensor of the present invention, the reliability of the sensor is improved without damaging the winding and the lead wire by the soldering work, and the coil winding size is changed in the slider moving direction. The same bobbin size and the same output performance as before can be realized.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. In the drawings, the same parts are designated by the same reference numerals. FIG. 1 shows a torque sensor 5 according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view in the axial direction showing the state in which 0 is attached to the electric power steering device 100.

In FIG. 1, an electric power steering apparatus 100 is inserted and mounted in a cylindrical lower column 22,
An input shaft 10, which is connected to a steering wheel (not shown) via a mechanism (not shown) and transmits the steering force of the steering wheel, is arranged concentrically with the input shaft 11, and a vehicle wheel via a mechanism (not shown). Output shaft 10 for steering
And a torsion bar 18 as an elastic member inserted in the end portions of the input shaft 10 and the output shaft 11 which face each other.

The input shaft 1 in which the torsion bar 18 is inserted.
0 and the end of the output shaft 11 are housed in the main body of the torque sensor 50, that is, the housing 17. The output shaft 11 is rotatably supported by the housing cover 30 of the torque sensor 50 via a bearing 17. The input shaft 10 is rotatably supported by the housing 17. The housing 17 and the housing cover 30 constitute a gear box that houses a gear device and the like.

A cylindrical slider member 19 is fitted and fixed to the outer periphery of the input shaft 10 and rotates integrally with the input shaft 10. Further, the slider member 19 is provided on the torsion bar 18
The shaft slides in the axial direction of the input shaft 10 in accordance with the twist of the. A detection element of the torque sensor 50, that is, a detection coil unit 20 that is a sensor unit that detects torque is arranged so as to face the outer periphery of the slider member 19 with a predetermined minute gap therebetween. The detection coil unit 20 is connected to the detection circuit unit 27 of the substrate 25 by a cable 21. By changing the relative opposing positions of the detection coil unit 20 and the slider member 19 according to the sliding of the slider member 19 in the axial direction, the torque is detected as the self-inductance change of the detection coil unit 20 based on the amount of movement. It

That is, when torque is input from the input shaft 10 and the torsion bar 18 is twisted as in the embodiment shown in FIG. 1, the pin 52 and the input shaft 10 permitting relative rotation between the input shaft 10 and the output shaft 11. The ball 53 moving in the spiral groove on the output shaft 10 by the relative rotation between the output shaft 11 and the output shaft 11, and the cross guide 5 moving in the axial direction according to the movement of the ball 53.
With the known mechanism of 1, the slider member 19 moves in the axial direction according to the twist amount of the torsion bar 18.
The movement of the slider member 19 is detected by the detection coil unit 20, and the detection circuit unit 27 including a differential amplifier outputs an electric signal.

FIG. 2 is an assembly diagram showing the details of the detection coil section 20. The detection coil unit 20 has a substantially cylindrical coil yoke 61, two annular bobbins 62 fitted to the coil yoke 61 from both ends in the axial direction, and the coil yoke 61 fitted from the outside of the bobbin 62 so as to close the coil yoke 61. It is made up of individual yoke covers 63.

The bobbin 62 includes a cylindrical portion 60 having a predetermined radius, and an annular first flange portion 64 and a second flange portion 65 which are provided at both axial ends of the cylindrical portion 60 and extend radially outward. , And an annular third flange portion 69 provided on the outer circumference of the cylindrical portion 60 between the first and second flange portions 64 and 65 and extending outward in the radial direction. A first groove 68 is provided on the outer circumference of the cylindrical portion 60 between the first flange portion 64 and the third flange 69, and a second flange portion 65 is provided.
Between the second flange 69 and the third flange 69, the second portion is formed on the outer circumference of the cylindrical portion 60.
Grooves 75 are defined respectively.

The radial height of the first flange portion 64 is
It is smaller than the radial height of the second flange portion 65. The inner diameter of the bobbin yoke 61 is set larger than the diameter of the first flange portion 64 and smaller than the diameter of the second flange portion 65. Therefore, the bobbin 6 is attached to the bobbin yoke 61.
When fitting 2 together, as shown in FIG. 2, the first flange 64 is inserted into the bobbin yoke 61 so that the first flange 64 is located inside.
If it is assembled in the opposite way, the second flange portion 65 is larger than the inner diameter of the bobbin yoke 61 and therefore cannot be inserted. In this way, it is possible to prevent the bobbin 62 from being assembled in the bobbin yoke 61 in the wrong direction.

Here, the axial width of the first groove 68 is smaller than the axial width of the second groove 75. The sensor coil 71 (see FIG. 3) is wound around the second groove 75, and the end portion of the sensor coil 71 passes through the notch 66 provided in the third flange portion 69 and is fitted into the first groove 68. Will be placed. The sensor coil 71 is not wound around the first groove 68, and the lead wire shown in FIG. 1, that is, the end portion of the cable 21 is arranged in the first groove 68.
And the end of the cable 21 are entangled with each other to connect them by soldering. In this state, the sensor coil 71 and the cable 21 together with the connecting portion 70 are fixed in the first groove 68 by filling an adhesive. Sensor coil 7
1 and the cable 21 are connected by soldering in the first groove 68 separated from the second groove 75 by the third flange portion 69, and thus the sensor coil wound in the second groove 75. It is possible to prevent the 71 from being damaged by soldering. The other end of the cable 21 is the bobbin yoke 6
It is connected to the connector 72 (FIG. 3) through the notch 67 provided in 1. The first flange portion 64 and the third flange portion 69 have the same diameter in the embodiment, but they do not necessarily have to have the same diameter, and may have a diameter smaller than at least the second flange portion 65. Good.

Next, details of the bobbin 62 will be described with reference to FIGS. FIG. 3 is an enlarged view of a main part of the detection coil section showing the relationship between the bobbin 62 and the cable 21. FIG. 4 is an enlarged view of a main part of a conventional detection coil section showing the relationship between the bobbin 102 and the cable 101. As is apparent from FIG. 3, the cable 21 is fixed to the end portion of the second groove 75 by being fixed, and traverses the second groove 75 in the axial direction through the notch 66 of the third flange portion 69. Into the first groove 68. First
In the groove 68, the lead wire for detection wound around the second groove 75, that is, the end portion of the sensor coil 71 is also similarly arranged. The cable 21 is connected to the end of the sensor coil 71 in the first groove 68 by soldering. The connecting portion 70 between the cable 21 and the sensor coil 71 is fixed and fixed to the first groove 68 with an adhesive. Therefore, since the soldering work of the cable 21 and the sensor coil 71 and the fixing work with the adhesive are all performed in the first groove 68, the sensor coil 71 in the second groove 75 is damaged by these operations. Can be prevented.

FIG. 4 shows a conventional bobbin. The cable 101 extending from the connector 106 crawls into a single groove 102 defined by a bobbin flange 103 and is soldered to the sensor coil 104 on the groove 102. Therefore, the wound sensor coil 104 may be damaged by soldering work or the like.

As is apparent from FIGS. 3 and 4, both the bobbin 62 of the present embodiment and the conventional bobbin 102 have the same axial width a. Therefore, it is possible to form the first groove 68 for the soldering work of the cable 21 and the sensor coil 71 and the fixing work with the adhesive without changing the axial width of the bobbin, that is, without increasing the width. This can prevent the device from becoming unnecessarily large.

Next, the influence of the disturbance magnetic field acting on the sensor coil will be described with reference to FIGS. The sensor coil is wound in the same direction so that the differential amplifier cancels the in-phase component even if the disturbance magnetic field generated by the electric motor of the electric power steering or other electric components mounted on the vehicle is transmitted to the input / output shaft. For example, as shown in FIG. 5, when the disturbance magnetic field in the direction indicated by the arrow acts, the bobbin 62
The winding direction of the sensor coil is as illustrated. Accordingly, the in-phase component can be canceled by the differential amplifier of the detection circuit unit 27, so that the detection result of the torque sensor is not affected by the disturbance magnetic field. On the contrary, as shown in FIG. 6, if the sensor coils are improperly assembled, the influence of the disturbance magnetic field tends to be synergistic. For this reason, in the embodiment of the present invention, the diameter of the flange portion of the bobbin is different between the front and the rear so that the bobbin cannot be reversely assembled and is not affected by the disturbance magnetic field.

Further, the first grooves are arranged on the opposite sides (inner sides) so that the windings of the sensor coil are arranged on the axial end side of the slider member, and the sensor coil is arranged in the moving direction of the slider member. The output does not change (gain does not become low) even if the width dimension is changed (decreased). Moreover, the outer dimensions of the bobbin are the same as those of the conventional one, so that they do not extend in the axial direction (see FIGS. 3 and 4).

[0024]

According to the torque sensor of the present invention described above, the following effects can be obtained.

According to the present invention, the groove for winding the sensor coil and the groove for connecting the ends of the sensor coil and the lead wire of the detection circuit portion are separately configured, so that the winding and the lead wire can be formed by soldering. The reliability as a sensor is improved without damaging the wire.

Further, according to the embodiment, there is an effect that the same bobbin size and the same output performance as the conventional one can be realized even though the coil winding size is changed in the slider member moving direction.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view in the axial direction showing a state in which a torque sensor according to an embodiment of the present invention is attached to an electric power steering device.

FIG. 2 is an assembly diagram showing details of a detection coil unit.

FIG. 3 is an enlarged view of a main part of a detection coil section showing a relationship between a bobbin and a cable.

FIG. 4 is an enlarged view of a main part of a conventional detection coil section showing a relationship between a bobbin and a cable.

FIG. 5 is an explanatory diagram of an influence of a disturbance magnetic field acting on a sensor coil.

FIG. 6 is an explanatory diagram of an influence of a disturbance magnetic field acting on a sensor coil.

[Explanation of symbols]

 50 torque sensor 20 detection coil 62 bobbin 64, 65, 69 flange 68, 75 groove

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[Procedure amendment]

[Submission date] January 22, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

In order to achieve the above object, a torque sensor of the present invention converts a twist of a shaft into a moving amount of a slider member, and detects the moving amount of the slider member as a self-inductance change of a detecting coil portion. In the torque sensor for detecting by the circuit part, the detection coil part is composed of a bobbin around which a coil is wound, and the bobbin has a cylindrical part and annular first and second flange parts provided at both axial ends of the cylindrical part. And an annular third portion between the first and second flange portions.
A second flange portion is provided, and the coil has a second flange portion defined between the second flange portion and the third flange portion.
Of the coil, and the end of the coil is connected to the detection circuit section at a first groove defined between the first flange portion and the third flange portion. It is characterized by being connected and fixed to the wire.

Claims (1)

[Claims] 1. A torque sensor for converting a twist of a shaft into a movement amount of a slider member and detecting the movement amount of the slider member as a change in self-inductance of a detection coil unit by a detection circuit unit, wherein the detection coil unit includes a coil. It consists of a bobbin to wind
The bobbin has a cylindrical portion and annular first and second flange portions provided at both ends in the axial direction of the cylindrical portion, and an annular third flange is provided between the first and second flange portions. The coil is wound around a second groove defined at an end of the coil between the second flange portion and the third flange portion, and Is connected to and fixed to a lead wire connected to the detection circuit portion in a first groove defined between the first flange portion and the third flange portion. Torque sensor.