JPH09178513A - Rotational angle sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect rotary shaft and oil seal against damage by making a plurality of grooves radially in the inner surface of a coupling means disposed oppositely to a housing and an oil seal thereby discharging intruded sand or pebble through the grooves to the outside as the coupling means turns. SOLUTION: In the rotational angle sensor 10, a plurality of grooves are made radially in the inner surface 12 of a coupling means 11 disposed oppositely to a housing 51 and an oil seal 57. Consequently, sand or a pebble intruded into the gap 14 between the inner surface 12 of coupling means 11 and the housing 51 rolls downward in the groove 13 as the coupling means 11 turns and discharged to the outside of coupling means 11 and housing 51. This structure suppresses trapping of sand or pebble and protects the rotary shaft 53 against locking, bending and breaking while protecting the oil seal 57 against damage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle sensor, and more particularly to a rotation angle sensor mounted on a civil engineering machine such as a backfor and used for detecting a bending angle of a movable arm.

[0002]

2. Description of the Related Art FIG. 5 is a cross-sectional view schematically showing a conventional rotation angle sensor of this type, and reference numeral 51a in the drawing denotes a housing body. The housing body 51a is formed into a substantially bottomed cylindrical shape,
A lid 51b having a substantially convex cross-section is provided at the lower end of the housing body 51a.
Are attached, and these housing body 51a and lid 5 are attached.
The housing 51 is configured to include 1b. Case body 51
Bearing parts 52 such as ball bearings are arranged on the central axes of the upper part a and the upper part of the lid 51b, respectively, and a rotary shaft 53 is inserted in the bearing parts 52. A cylindrical portion 54 is inserted in the outer periphery of the substantially central portion of the rotating shaft 53, and the cylindrical portion 54 and the rotating shaft 53 are connected via a key 54a or the like.
A rotary plate 55 is attached to the cylindrical portion 54 orthogonally thereto, and a slit 55a having a width W is formed in the rotary plate 55. The shape of the slit 55a is proportional to the rotation angle of the rotary plate 55. The distance from the center is set to gradually increase. A light source 56a is provided above the rotary plate 55, and a light position detection element 56b is provided at a position facing the light source 56a with the rotary plate 55 interposed therebetween.
The light position detection element 56b and the light source 56a are the circuit board 56c.
It is electrically connected via the and is integrally attached to the inside of the housing 51. A substantially ring-shaped oil seal 57 is interposed between the upper part of the housing body 51a and the rotary shaft 53, and the oil seal 57 prevents dust and moisture from entering the housing 51. Has become. Further, at one end of the rotary shaft 53, a substantially disk-shaped connecting means 58 is provided.
Is attached to the inner surface 58a of the connecting means 58,
The gap 58b between the housing 51 and the facing surface 51c of the connecting means 58 is set to a predetermined distance D. Also, the connecting means 5
Reference numeral 8 is connected to a movable arm shaft such as a back force (both not shown), while the housing 51 is attached to a fixed portion (not shown) near the movable arm shaft. These housing 51, rotating shaft 53, rotating plate 55, light source 5
The rotation angle sensor 50 is configured to include 6a, the optical position detecting element 56b, the connecting means 58, and the like.

In the rotation angle sensor 50 constructed as described above, when the rotary plate 55 rotates via the connecting means 58 and the rotary shaft 53 as the movable shaft rotates, the slit 55a is formed in proportion to the rotation angle. The rotary plate 55 moves in the radial direction. Then, the light emitted from the light source 56a receives the slit 55.
By passing through a and irradiating the optical position detecting element 56b, a photocurrent is generated in the optical position detecting element 56b, the irradiation position is detected by this photocurrent, and the bending angle of the movable arm with respect to the fixed portion is detected. It

[0004]

In the rotation angle sensor 50 described above, the inner surface 58a of the connecting means 58 and the housing 5 are connected.
It is easy for sand and pebbles to enter the gap 58b between the first facing surface 51c and the oil seal 57 and be caught. Then, when these earth and sand or small stones are caught, the rotation shaft 53 is locked and the rotation angle becomes temporarily undetectable, or when the movable shaft is forcibly rotated, the rotation shaft 53 is bent or broken. There is a problem that the oil seal 57 may be generated or dust or moisture may enter the housing 51 due to damage.

The present invention has been made in view of the above problems, and it is possible to prevent dirt, pebbles, or the like from being caught between the inner surface of the connecting means and the opposing surface of the housing or the oil seal. Also, it is possible to prevent the rotation shaft from locking, bending, breaking, or breaking the oil seal.As a result, it is possible to detect the rotation angle in a stable and reliable manner even in a work environment where there is a large amount of scattering of earth and sand and pebbles. It is an object of the present invention to provide a rotation angle sensor capable of

[0006]

In order to achieve the above object, a rotation angle sensor according to the present invention comprises a housing,
A rotating shaft disposed in the housing, an oil seal interposed between the rotating shaft and the housing, and attached to one end of the rotating shaft so as to face the housing and the oil seal. In the rotation angle sensor having the connecting means, a plurality of grooves are radially formed on the inner surface of the connecting means (1).

According to the rotation angle sensor (1) described above, since a plurality of grooves are radially formed on the inner surface of the connecting means facing the housing and the oil seal, the inner surface of the connecting means is When the earth and sand or pebbles enter between the housing and the oil seal, the earth and sand or pebbles roll into the groove as the connecting means rotates,
It is easily discharged to the outside of the connecting means and the casing through the groove. Therefore, the occurrence of biting of the earth and sand or the small stones is suppressed, and it is possible to prevent the rotation shaft from being locked / bent / broken and the oil seal from being damaged. As a result, the rotation angle can be detected stably and reliably even in a working environment in which the earth and sand and the pebbles are easily scattered.

Further, the rotation angle sensor according to the present invention includes a housing, a rotating shaft arranged in the housing, an oil seal interposed between the rotating shaft and the housing, and the rotating shaft. In a rotation angle sensor comprising a casing and a connecting means attached to the one end of the shaft so as to face the oil seal, a face-to-face relationship between the casing and the connecting means as the distance from the axis of the rotating shaft increases. The inner surface of the connection means and / or the surface of the housing facing the connection means has a taper angle so that the distance gradually increases (2).

According to the above rotation angle sensor (2), the inner surface of the connecting means and / or the inner surface of the connecting means is gradually increased so that the surface distance between the housing and the connecting means gradually increases as the distance from the axis of the rotating shaft increases. The facing surface of the housing with respect to the connecting means has a taper angle, and a component force in the radial direction is generated as the connecting means rotates, so that the earth and sand and pebbles that have entered the gap are in the radial direction. It is easily pushed out to the outside of the connecting means and the casing, and is quickly discharged. As a result, the same effect as that of the rotation angle sensor (1) can be obtained.

The rotation angle sensor according to the present invention is characterized in that, in the rotation angle sensor (2), a plurality of grooves are radially formed on the inner surface of the connecting means (3).

According to the rotation angle sensor (3) described above, the inner surface of the connecting means and / or the surface of the housing facing the connecting means has a taper angle, and a plurality of inner surfaces of the connecting means are provided. Since the individual groove portions are formed in a radial pattern, and the actions of the rotation angle sensors (1) and (2) work synergistically, the rotation shaft is locked / bent / broken due to the inclusion of the earth and sand or the small stones. Or, it is possible to further prevent damage to the oil seal, and as a result, the rotation angle is more stable even in a working environment where the earth and sand and the pebbles are easily scattered,
And it can detect more reliably.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a rotation angle sensor according to the present invention will be described below with reference to the drawings. Note that components having the same functions as those of the conventional example are denoted by the same reference numerals. 1A and 1B are schematic views showing a rotation angle sensor according to an embodiment, where FIG. 1A is a front sectional view and FIG. 1B is a bottom sectional view taken along the line AA in FIG. Similar to that shown in FIG. 5, the housing main body 51a is formed in a substantially bottomed cylindrical shape, and a lid 51b having a substantially convex cross section is attached to the lower end of the housing main body 51a. 51a, lid 51
The housing 51 is configured to include b. Case body 51a
Bearing parts 52 such as ball bearings are arranged on the central axes of the upper part and the upper part of the lid 51b, and a rotary shaft 53 is inserted in the bearing parts 52. A cylindrical portion 54 is inserted in the outer periphery of the substantially central portion of the rotating shaft 53, and the cylindrical portion 54 and the rotating shaft 53 are connected via a key 54a or the like. A rotary plate 55 is attached to the cylindrical portion 54 orthogonally thereto, and a slit 55a having a width W is formed in the rotary plate 55. The shape of the slit 55a is proportional to the rotation angle of the rotary plate 55. The distance from the center is set to gradually increase. The light source 56a is disposed above the rotating plate 55, while the rotating plate 5 is provided at a position facing the light source 56a.
5, an optical position detecting element 56b is disposed with the optical position detecting element 56b interposed therebetween, and the optical position detecting element 56b and the light source 56a are electrically connected to each other via a circuit board 56c and are integrally mounted in the housing 51. ing. A substantially ring-shaped oil seal 57 is interposed between the upper part of the housing body 51a and the rotary shaft 53, and the oil seal 57 prevents dust and moisture from entering the housing 51. Has become.

On the other hand, a substantially disc-shaped connecting means 11 is attached to one end of the rotating shaft 53, and the inner surface 12 of the connecting means 11 and the surface 5 of the housing 51 facing the connecting means 11 are attached.
The gap 14 with respect to 1c is set to a predetermined distance D ₁ . The inner surface 12 of the connecting means 11 is formed with a plurality of substantially fan-shaped groove portions 13 radially extending in a bottom view radial direction. The connecting means 11 is connected to a movable arm shaft such as a back force (both not shown), while the housing 51 is attached to a fixed portion (not shown) near the movable arm shaft. . These connecting means 11, groove 12,
The rotation angle sensor 10 is configured to include the housing 51, the rotation shaft 53, the rotation plate 55, the light source 56a, the light position detection element 56b, and the like.

In the case of the rotation angle sensor 10 constructed as described above, when the rotary plate 55 rotates through the connecting means 11 and the rotary shaft 53 as the movable shaft rotates, the rotation angle sensor 50 shown in FIG. Similar to the case, the slit 55a moves in the radial direction of the rotary plate 55 in proportion to this rotation angle. Then, the light emitted from the light source 56a passes through the slit 55a and irradiates the optical position detecting element 56b, whereby a photocurrent is generated in the optical position detecting element 56b, and the irradiation position is detected by this photocurrent, and The bending angle of the movable arm with respect to the fixed portion is detected. When the connecting means 11 rotates as the movable shaft rotates, the earth and sand and pebbles that have entered the gap 14 roll into the groove 12 and move along the groove 12.

As is apparent from the above description, in the rotation angle sensor 10 according to the first embodiment, a plurality of grooves 13 are radially formed on the inner surface 12 of the connecting means 11 facing the housing 51 and the oil seal 57. Connection means 11
1 between the inner surface 12 of the casing and the housing 51 or the oil seal 57
When the earth and sand and the pebbles get into 4, the earth and sand and the pebbles roll into the groove portion 13 as the connecting means 11 rotates,
It is easily discharged to the outside of the connecting means 11 and the housing 51 along the groove 13. Therefore, the occurrence of biting of the earth and sand or the small stones is suppressed, and it is possible to prevent the rotation shaft 53 from being locked, bent, or broken, and the oil seal 57 from being damaged. As a result, the rotation angle can be detected stably and reliably even in a working environment in which the earth and sand and the pebbles are easily scattered.

In the rotation angle sensor according to another embodiment, the groove portions 13 may communicate with each other via the communication groove 13a as shown by the broken line in FIG. 1 (b). In this case, when the rotating shaft 53 is set horizontally and is used for attachment, the earth and sand and pebbles that have fallen into the upper groove portion 13 should always be smoothly removed through the connecting groove 13a and the lower groove portion 13. You can

FIG. 2 is a front cross-sectional view schematically showing the vicinity of the connecting means of the rotation angle sensor according to the second embodiment, and 53 in the drawing indicates a rotating shaft. A substantially disk-shaped connecting means 21 is attached to one end of the rotary shaft 53. The inner surface 22 of the connecting means 21 has a taper angle α, and as it moves away from the axis of the rotating shaft 53, the facing surface 51 of the housing 53 is formed.
The surface distance D ₂ between c and the inner surface 22 of the connecting means 21 gradually increases. Since other configurations are similar to those shown in FIG. 1, detailed description of the configuration will be omitted here. These connecting means 21 and housing 5
1, the rotation angle sensor 20 is configured to include the rotating shaft 53, the oil seal 57, and the like.

In the case of the rotation angle sensor 20 constructed as described above, when the connecting means 21 is rotated, a radial component force is generated on the earth and sand and the pebbles that have entered the gap 23 between the facing surface 51c and the inner surface 22. .

As is apparent from the above description, in the rotation angle sensor 20 according to the _second embodiment, the surface distance D ₂ between the housing 51 and the connecting means 21 increases with distance from the axis of the rotation shaft 53.
Since the inner surface 22 of the connecting means 21 has a taper angle α so that it gradually expands, and a component force in the radial direction is generated as the connecting means 21 rotates, the sand and sand that has entered the gap 23 is generated. The pebbles and pebbles are easily pushed out in the radial direction, and are quickly discharged to the outside of the connecting means 21 and the casing 51. As a result, the same effect as that of the rotation angle sensor 10 can be obtained.

FIG. 3 is a front sectional view schematically showing the vicinity of the connecting means of the rotation angle sensor according to another embodiment, and 53 in the drawing denotes a rotation shaft. A connecting means 58 similar to that shown in FIG. 5 is attached to one end of the rotary shaft 53. On the other hand, the facing surface 31a of the housing 31 facing the connecting means 58 has a taper angle β, and the facing surface 31a of the housing 31 and the inner surface 58a of the connecting means 58 become farther away from the axis of the rotating shaft 53. The face-to-face distance D ₃ is gradually increased. Since other configurations are similar to those shown in FIG. 1, detailed description of the configuration will be omitted here. The rotation angle sensor 30 is configured to include the housing 31, the rotating shaft 53, the oil seal 57, the connecting means 58, and the like.

In the case of the rotation angle sensor 30 thus constructed, when the connecting means 58 is rotated, a radial component force is generated in the earth and sand and the pebbles that have entered the gap 32 between the facing surface 31a and the inner surface 58a. .

As is apparent from the above description, in the rotation angle sensor 30 according to another embodiment, the surface distance D between the housing 31 and the connecting means 58 increases as the distance from the axis of the rotation shaft 53 increases.
_{Since the} facing surface 31a of the housing 31 with respect to the connecting means 58 has a taper angle β so that ₃ gradually expands, the same effect as that of the rotation sensor 20 can be obtained.

In the rotation angle sensor according to another embodiment, the inner surface 58a of the connecting means 58 shown in FIG. 3 may have a taper angle α.

4A and 4B are schematic views showing the vicinity of the connecting means of the rotation angle sensor according to the third embodiment. FIG. 4A is a front sectional view and FIG. 4B is a bottom sectional view taken along the line AA in FIG. Is. The one end of the rotary shaft 53 has a substantially disc-shaped connecting means 41.
Is attached. The inner surface 42 of the connecting means 41 has a taper angle α, and as the distance from the axis of the rotating shaft 53 increases, the surface distance D ₃ between the facing surface 51c of the housing 53 and the inner surface 42 of the connecting means 41 gradually increases. It is designed to spread. Further, a plurality of groove portions 43 that are substantially parallel to each other in a bottom view are radially formed on the inner surface 42 of the connecting means 41. Since other configurations are similar to those shown in FIG. 1, detailed description of the configuration will be omitted here. The rotation angle sensor 40 is configured by including the connecting means 41, the groove portion 43, the housing 51, the rotating shaft 53, the oil seal 57, and the like.

In the case of the rotation angle sensor 40 constructed as described above, when the connecting means 41 is rotated, a component force in the radial direction is generated and the earth and sand or pebbles that enter the gap 44 between the facing surface 51c and the inner surface 42. Is pushed outward and the groove 4
It rolls into the inside of the groove 3 and moves outward along the groove 12.

As is apparent from the above description, in the rotation angle sensor 40 according to the third embodiment, the inner surface 4 of the connecting means 41 is used.
2 has a taper angle α, and a plurality of grooves 43 are radially formed on the inner surface 42 of the connecting means 41,
Since the actions of the rotation angle sensors 10 and 20 work synergistically, it is possible to further prevent the rotation shaft 53 from being locked / bent / broken due to the trapping of earth and sand or small stones, and the oil seal 57 from being damaged. The rotation angle can be detected more stably and more reliably even in a work environment in which dirt and pebbles are easily scattered.

The rotation angle sensor 4 according to the third embodiment.
In No. 0, the case where the inner surface 42 of the connecting means 41 has the taper angle α has been described, but in another embodiment, the facing surface 51c may have the taper angle, and still another case. In the embodiment, the inner surface 42 may have the taper angle α and the facing surface 51c may have the taper angle β.

Further, the rotation angle sensor 4 according to the third embodiment
In No. 0, the case where the groove portion 43 is formed up to the outer edge portion of the coupling means 41 has been described, but the groove portion may be formed halfway along the outer edge portion.

Further, in the above-described first and third embodiments, the case where the number of the groove portions 13 and 43 is six has been described.
The number is not limited to six.

Further, in the above-described first to third embodiments, the case where all the connecting means 11, 21, 41 and 58 are substantially disc-shaped has been described, but in the other embodiments, it is omitted. It may be rectangular.

Further, in the above-described first to third embodiments, the bearing portions 52 are separately arranged in the vertical direction, and
The case where the light source 56a is disposed above and the light position detection element 56b is disposed below the rotary plate 55 is described, but the position is not limited to this.

[Brief description of the drawings]

1A and 1B are schematic diagrams showing a first embodiment of a rotation angle sensor according to the present invention, where FIG. 1A is a front sectional view and FIG. 1B is a bottom sectional view taken along the line AA in FIG.

FIG. 2 is a front sectional view schematically showing the vicinity of a connecting means of a rotation angle sensor according to a second embodiment.

FIG. 3 is a front sectional view schematically showing the vicinity of a connecting means of a rotation angle sensor according to another embodiment.

4A and 4B are schematic views showing the vicinity of a connecting means of a rotation angle sensor according to a third embodiment, where FIG. 4A is a front sectional view and FIG.
FIG. 4A is a bottom cross-sectional view taken along line AA in (a).

FIG. 5 is a cross-sectional view schematically showing a conventional rotation angle sensor.

[Explanation of symbols]

 10 Rotation Angle Sensor 11 Coupling Means 12 Inner Surface 13 Groove 51 Housing 53 Rotating Shaft 57 Oil Seal

Claims (3)

[Claims] 1. A housing and a rotating shaft disposed in the housing,
A rotation angle sensor comprising: an oil seal interposed between the rotary shaft and the casing; and a connecting means attached to one end of the rotary shaft so as to face the casing and the oil seal. A rotation angle sensor, wherein a plurality of grooves are radially formed on the inner surface of the connecting means. 2. A housing, and a rotating shaft arranged in the housing,
A rotation angle sensor comprising: an oil seal interposed between the rotary shaft and the casing; and a connecting means attached to one end of the rotary shaft so as to face the casing and the oil seal. , The inner surface of the connecting means and / or the surface of the housing facing the connecting means has a taper angle so that the surface distance between the housing and the connecting means gradually increases with increasing distance from the axis of the rotating shaft. A rotation angle sensor having. 3. The rotation angle sensor according to claim 2, wherein a plurality of grooves are radially formed on the inner surface of the connecting means.