JP2006300716A - Torque sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque sensor which is safe even when a connection part connecting an inner wheel and an outer wheel is broken. <P>SOLUTION: The torque sensor has the inner wheel 12 inserted in the middle of two coaxial rotary shafts 17, 18 and fixed to an end part 17a of one of the two rotary shafts, the outer wheel 11 formed by forming a slit 14 between it and the outer circumference of the inner wheel 12 so as to surround the outer circumference and fixed to an end part 18a of the other of the two rotary shafts, and the connection parts 13 formed at a plurality of points in the circumferential direction between the inner wheel 12 and the outer wheel 11, masking the slit 14, and connecting the inner wheel 12 and the outer wheel 11. The torque is detected by distortion of the connection parts 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a torque sensor that detects torque of a rotating shaft.

  Conventionally, for example, a torque sensor as shown below has been disclosed as a torque sensor for detecting the torque of a rotating shaft (see, for example, Patent Document 1).

  4 is a perspective view in which a part of the conventional torque sensor is cut, and FIG. 5 is a cross-sectional view of the conventional torque sensor shown in FIG.

  As shown in FIG. 4, this torque sensor includes an outer ring 1 formed so as to surround the outer periphery by forming a slit 4 between the inner ring 2 and the outer periphery of the inner ring 2, and the inner ring 2 and the outer ring 1. There are a plurality of connecting portions 3 formed between the inner ring 2 and the outer ring 1 by blocking the slit 4 and a strain gauge 5 attached to the connecting portion 3. Torque is detected by strain.

As shown in FIG. 5, the torque sensor is inserted between two coaxial rotating shafts 7 and 8, and the inner ring 2 is fixed to one end 7 a of the two rotating shafts 7 and 8. The outer ring 1 is fixed to the other end 8a of the two rotating shafts 7 and 8. In this torque sensor, the connecting portion 3 that connects the inner ring 2 and the outer ring 1 to each other has a structure that is more easily deformed than the inner ring 2 and the outer ring 1, so that the strain detection accuracy by the strain gauge 5 is increased. It is configured.
German Patent No. 4820522 (page 1-3, FIGS. 1-3)

  However, in the above torque sensor, when an excessive load is applied to the rotating shaft, the connecting portion may be damaged. If the rotating shaft system has a degree of freedom in the thrust direction, the inner ring and the outer ring There is a risk that the shaft, inner ring, outer ring, etc. may be scattered due to disconnection.

  FIG. 6 is a diagram illustrating a case where a connecting portion of a conventional torque sensor is damaged.

  As shown in FIG. 6, when an excessive load is applied to the rotating shaft of the torque sensor, the connecting portion 3 is damaged, the inner ring 2 is detached from the outer ring 1, and the rotating shaft 7 and the inner ring 2 are scattered. May cause a major accident.

  In order to prevent such a scattering accident, it is considered that the gap between the slits 4 (see FIG. 4) is made as narrow as possible so that the inner ring 2 is not easily detached even if the connecting portion 3 is damaged. It is done.

  However, as long as it is a torque sensor that detects torque by attaching a strain sensor to the connecting part, the minimum required slit gap is indispensable, and it is difficult to narrow the slit gap to the extent that the inner ring does not come off. It cannot be a sufficient safety measure.

  In view of the above circumstances, an object of the present invention is to provide a safe torque sensor even when a connecting portion that connects an inner ring and an outer ring is damaged.

The torque sensor of the present invention that solves the above problems is
Inserted between two coaxial rotating shafts,
An inner ring fixed to one end of the two rotating shafts;
An outer ring that is formed so as to surround the outer periphery of the inner ring and is fixed to the other end of the two rotating shafts;
A plurality of circumferentially formed portions between the inner ring and the outer ring are provided to connect the inner ring and the outer ring by blocking the slit, and torque is detected by distortion of the connecting portion. In the torque sensor,
The inner ring has an outer periphery whose diameter changes in the rotation axis direction,
The outer ring has an inner circumference whose diameter changes in the direction of the rotation axis, facing the outer circumference of the inner ring across the slit.

  According to the torque sensor of the present invention, even when an excessive load is applied to the torque sensor and the connecting portion is broken, the coupling between the inner ring and the outer ring is difficult to be removed, so that an accident of scattering of the rotating shaft, the inner ring, and the outer ring is prevented. be able to.

  Here, the outer periphery of the inner ring and the inner periphery of the outer ring may have a circular shape around the rotation axis with the slit interposed therebetween.

  When the torque sensor according to the present invention is configured as described above, the torque sensor manufacturing process and assembly process are facilitated, so that a relatively low cost torque sensor can be obtained.

  The outer circumference of the inner ring and the inner circumference of the outer ring may have a non-circular shape around the rotation axis with the slit interposed therebetween.

  When the torque sensor according to the present invention is configured as described above, the inner ring and the outer ring are more difficult to come off, and the effect of preventing a scattering accident can be improved.

  Further, since a rotational force can be transmitted to some extent at the same time, it is possible to prevent a sudden change in the rotational speed.

  According to the torque sensor of the present invention, a safe torque sensor can be realized even when the connecting portion that connects the inner ring and the outer ring is damaged.

  Embodiments of a torque sensor according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view showing an appearance of the torque sensor according to the first embodiment, and FIG. 2 is a cross-sectional view taken along the line AA of the torque sensor shown in FIG.

  As shown in FIGS. 1 and 2, the torque sensor 100 is inserted between two coaxial rotary shafts 17 and 18 and is fixed to one end 17 a of the two rotary shafts. And an outer ring 11 formed so as to surround the outer periphery by forming a slit 14 between the outer ring 11 and the inner ring 12, and fixed to the other end 18 a of the two rotating shafts, and the inner ring 12 and the outer ring 11 has four connecting portions 13 formed in the circumferential direction between the inner ring 12 and the outer ring 11 so as to connect the inner ring 12 and the outer ring 11, and detect torque by distortion of the connecting portion 13. is there.

  In the torque sensor 100 of the first embodiment, the inner ring 12 has an outer periphery 12a whose diameter changes in the direction of the rotation axis, and the outer ring 11 faces the outer periphery of the inner ring 12 with the slit 14 interposed therebetween, so that the rotation axis direction. The inner ring 11 has an inner circumference 11a whose diameter changes, and the outer circumference 12a of the inner ring 12 and the inner circumference 11a of the outer ring 11 have a circular shape around the rotation axis with the slit 14 interposed therebetween.

  By configuring as described above, even when the torque sensor 100 is overloaded and the connecting portion 13 is damaged, the inner ring 12 remains in the state shown by the broken line, and the safety does not come off the outer ring 11. A torque sensor can be realized.

  Next, a torque sensor according to a second embodiment will be described.

  FIG. 3 is a perspective view illustrating an appearance of the torque sensor according to the second embodiment.

  As shown in FIG. 3, the torque sensor 200 according to the second embodiment is inserted between two coaxial rotating shafts as in the torque sensor 100 according to the first embodiment (see FIG. 1). A slit 24 is formed between the inner ring 22 fixed to one end of the two rotation shafts and the outer periphery of the inner ring 22 so as to surround the outer periphery. An outer ring 21 fixed to the other end of the inner ring 22 and four connecting portions 23 formed between the inner ring 22 and the outer ring 21 in the circumferential direction so as to block the slit 24 and connect the inner ring 22 and the outer ring 21. The torque is detected by the strain gauge 15 attached to the connecting portion 23.

  In the second embodiment, the outer periphery 22a of the inner ring 22 and the inner periphery 21a of the outer ring 21 are different from those in the first embodiment (see FIG. 1), as shown in FIG. The inner circumference 21 a of the outer ring 21 has a non-circular shape around the rotation axis with the slit 24 interposed therebetween.

  With the above-described configuration, in the torque sensor 200, even when an excessive load is applied and the connecting portion 23 that connects the inner ring 22 and the outer ring 21 is damaged, the coupling between the inner ring 22 and the outer ring 21 may be released. Thus, it is possible to realize a torque sensor that can prevent rotation and is temporarily transmitted in a state in which the connecting portion 23 is damaged, and can maintain the rotation state relatively safely until the stop.

It is a perspective view which shows the external appearance of the torque sensor of 1st Embodiment. It is AA sectional drawing of the torque sensor shown in FIG. It is a perspective view which shows the external appearance of the torque sensor of 2nd Embodiment. It is the perspective view which cut | disconnected a part of conventional torque sensor. It is sectional drawing of the conventional torque sensor shown in FIG. It is a figure which shows the case where the connection part of the conventional torque sensor shown to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Inner ring 3 Connection part 4 Slit 5 Strain gauge 7, 8 Rotation shaft 7a, 8a End part 11 Outer ring 11a Inner circumference 12 Inner ring 12a Outer part 13 Connection part 14 Slit 15 Strain gauge 17, 18 Rotation axis 17a, 18a End part 21 Outer ring 21a Inner circumference 22 Inner ring 22a Outer circumference 23 Connecting portion 24 Slit 100, 200 Torque sensor

Claims (3)

Inserted between two coaxial rotating shafts,
An inner ring fixed to one end of the two rotating shafts;
An outer ring formed so as to surround the outer periphery by forming a slit between the outer periphery of the inner ring and fixed to the other end of the two rotating shafts;
A plurality of circumferentially formed portions between the inner ring and the outer ring, each having a connecting portion that blocks the slit and connects the inner ring and the outer ring, and detects torque by distortion of the connecting portion. In the torque sensor,
The inner ring has an outer periphery whose diameter changes in the rotation axis direction,
The torque sensor according to claim 1, wherein the outer ring has an inner periphery whose diameter changes in the direction of the rotation axis, facing the outer periphery of the inner ring across the slit.   The torque sensor according to claim 1, wherein an outer periphery of the inner ring and an inner periphery of the outer ring have a circular shape around a rotation axis with the slit interposed therebetween.   2. The torque sensor according to claim 1, wherein an outer periphery of the inner ring and an inner periphery of the outer ring have a non-circular shape around a rotation axis across the slit.

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