JPH09105604A - Angle detection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily adjust the air gap of a sensor, to easily ensure the accurately of the sensor, to miniaturize an angle detection apparatus as a whole and to use the apparatus especially for a heavy load such as a construction machine or the like in the angle detection apparatus which uses two sensors and which is provided with redundancy. SOLUTION: Two sensors S1, S2 are installed between a housing 2 and its pressure lid 3 and a shaft 1 which is supported by a bearing 11 inside the housing 2. In the sensor S1 on one side, an angle-of-rotation detection face B1 is formed in the axial direction of the shaft 1. In the sensor S2 on the other side, an angle-of-rotation detection face B2 is formed in the radial direction. The sensor S1 on one side is used as a magnetic noncontact sensor, and the sensor S2 on the other side is used as a contact-type sensor for a potentiometer or the like. The bearing 11 is set to a preload state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in construction machines and industrial machines, and in particular, can detect a rotation angle in a state where a load is applied to a rotary shaft, and has two sensors to provide redundancy. The present invention relates to a rotation angle detecting device.

[0002]

2. Description of the Related Art Conventionally, as a rotation angle detecting device for high load, there is one shown in FIGS. 5 to 6 (for example, Japanese Patent Application No. 5-5).
6549). This detection device includes a lid 5 of the housing 51.
The rotation detection surface A2 is provided at the shaft end of the rotation shaft 52 so as to face one rotation detection surface A1 provided on the No. 4 and various sensors are arranged on these rotation angle detection surfaces A1 and A2. The rotating shaft 52 is a bearing 53 provided in the housing 51.
The one end portion 52a having a small diameter is supported through the shaft hole 57 and protrudes to the outside of the housing 51. It is proposed that the sensor be provided with redundancy by combining a contact type potentiometer and a non-contact type sensor, for example, so that highly accurate detection is possible. FIG. 6 shows these sensors R
1, R2, which is an example of a potentiometer, is composed of a substantially ring-shaped resistor 55a provided on the rotation angle detection surface A1 and a brush 55b provided on the rotation angle detection surface A2. The non-contact type sensor R2 includes a multi-pole magnetic pattern 56a provided on the rotation angle detection surface A2 and M for detecting the magnetic pattern 56a.
It is composed of a magnetic detector 56b such as an R element.

[0003]

In the above-mentioned conventional example, in order to provide redundancy, the sensor R1 which is a contact type potentiometer and the non-contact sensor R2 are combined to form two sensors R1 and R2 on the same plane. It is installed in. Therefore, the following problems occur. For example, when the non-contact sensor R2 is composed of a combination of the magnetic detector 56b such as an MR element and the magnetic pattern 56a, the air gap between the magnetic detector 56b and the surface of the magnetic pattern must be strictly controlled in order to increase the resolution. Need to manage. Also in the potentiometer type sensor R1, it is necessary to manage the air gaps of the rotation angle detection surfaces A1 and A2 in order to manage the contact pressure of the brush 55b against the resistor 55a. Therefore, two sensors R
If R1 and R2 are installed on the same plane, two sensors R1 and
The air gap of R2 is adjusted in one direction, which makes the adjustment complicated. If the two sensors R1 and R2 are installed on the same plane, the size becomes large in the radial direction, and the overall size of the angle detection device becomes large. If the accuracy of the sensors R1 and R2 is constant, the sensor R
The larger the diameter of the detection position of 1 and R2 is, the more advantageous it is to ensure the accuracy. However, if the two sensors R1 and R2 are installed on the same plane, in order to keep the two sensors R1 and R2 within the allowable dimension, It is necessary to reduce the size, which is disadvantageous in ensuring accuracy. For example, in an MR element, the air gap amount is generally the width of one pole of the magnet. In the case of the same resolution, the smaller the diameter of the sensor detection position, the smaller the width of one pole, and the smaller the air gap amount. There is a need. Therefore, it becomes difficult to ensure accuracy.

The present invention solves the above problems, and in an angle detecting device having redundancy using two sensors, it is easy to adjust the air gap of the sensor and secure the accuracy of the sensor, and further, the entire device. The purpose is to downsize.

[0005]

According to the angle detecting device of the present invention, two sensors are installed between a housing and its lid and a rotary shaft supported by bearings in the housing, and one sensor is provided. Has a rotation angle detection surface in the axial direction of the rotation shaft, and the other sensor has a rotation angle detection surface in the radial direction. According to this configuration, since the air gap adjustment directions of the two sensors are different, it is possible to adjust each independently. Since the two sensors are not installed on the same plane, the radial dimension can be reduced. Further, it is not necessary to reduce the diameter of the detection position of one sensor, and the detection positions of both sensors can be increased. It is preferable to provide a plurality of bearings and preload these bearings. By preloading in this way, the bearing rigidity is increased, and even if a large load is applied to the rotating shaft, the influence on the air gap is small and the rotation angle can be detected accurately. It is preferable that one of the two sensors is a contact sensor and the other is a non-contact sensor. In this way, by using two different types of sensors, it is less likely that large errors will occur in both sensors at the same time due to various error factors, and redundancy will further improve accuracy and reliability. Be certain.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. This angle detecting device incorporates a non-contact type sensor S1 having a rotation detecting surface B1 in the radial direction and a contact type sensor S2 having a rotation angle detecting surface B2 in the axial direction in a housing 2 and is non-contact. The signal processing circuit device 14 for amplifying the signal detected by the magnetic detector 10 of the shape sensor S1 and processing the rectangular wave is also incorporated. The non-contact sensor S1 includes the magnetic detector 10 and the magnetic drum 9, and the magnetic detecting element 10 includes an MR element (magnetoresistive element),
Hall elements are used. The contact sensor S2 is a potentiometer, and is composed of a resistor body 16 and a brush assembly 17.

The housing 2 is formed in a vertical cylindrical shape having an end wall at the upper end, has a collar 2a on the outer circumference of the opening at the lower end, and the lower end opening is closed by a pressing lid 3 which is a lid. . The holding lid 3 is fitted to a countersunk portion provided on the periphery of the lower end opening of the housing 2 and fixed to the housing 2 with a screw, and is fitted to an inner diameter surface of the housing 2 following the countersunk portion. The outer ring of the bearing 11 is pressed in via the spacer 5 in the shape of a circle. A sealing resin 34 is provided on the outer surface of the pressing lid 3.

The rotary shaft 1 is fitted in a housing 2
The large-diameter shaft portion 1a is rotatably supported by the individual bearings 11. The collar-shaped protrusion 1c at one end of the large shaft diameter portion 1a, the spacers 12 and 13 of the inner and outer rings, and the bearing width retainer 6 apply a fixed position preload to enhance rigidity. The small diameter portion 1b at one end of the rotary shaft 1 projects to the outside from a hole in the top plate portion of the housing 2, and a seal member 15 such as an oil seal is provided in the hole. The other end of the rotary shaft 1 has a stepped shape, and the bearing width retainer 6, the magnetic drum 9, and the brush assembly 17 are arranged concentrically with each other and fixed by screws. The magnetic drum 9 has a magnet band 9a of a magnetic pattern magnetized in multiple poles on the outer circumference, and the rotation angle detection surface B1 of the sensor S1 by the magnetic drum 9 is in the radial direction. The magnetic pattern of the magnet band 9a may be of an incremental type in which magnetic poles are provided at regular intervals or of an absolute type. A brush 17a is attached to the brush assembly 17 in the axial direction, and the rotation angle detection surface B2 of the sensor S2 using the brush 17a is in the axial direction.

The pressing lid 3 is a sensor S in the housing 2.
The space into which 1 and S2 are inserted is separated from the space into which the signal processing circuit device 14 is inserted. An electric resistor 16a (FIG. 4) and an electrode 16b forming a potentiometer are provided in a concentric ring shape on the sensor side surface of the presser lid 3 at a radial position corresponding to the brush assembly 17. The electric resistor 16 a and the electrode 16 b are provided on the resistor body 16 fixed to the holding lid 3. Further, a sensor fixing block 4 to which the magnetic detector 10 is fixed is fixed with a screw on the sensor side surface of the pressing lid 3 at a position corresponding to the magnet band 9a of the magnetic drum 9. The sensor fixing block 4 is fitted in a guide groove 5a provided in the spacer 5 as shown in FIG. 3 so as to be movable in the radial direction of the spacer 5.

In FIG. 1, the signal processing circuit device 14 of the magnetic detector 10 is fixed to the side of the pressing lid 3 opposite to the sensor, and the back plate 7 is fixed to the outside thereof. The space between the holding lid 3 and the back plate 7 is hardened with the sealing resin 34 after the adjustment inspection is completed. The signal processing circuit device 14 is one in which various electric elements are provided on a circuit board, and a cable 29 including the lead wire and the lead wire connected to the resistor body 16 is put together.
Are led out of the housing 2 in the radial direction, and are connected to an external device (not shown) from the connector 31 (FIG. 2).

According to this structure, the contact pressure between the resistor 16 of the potentiometer and the brush 17a is set by adjusting the air gap by axial dimension setting. For example, the thickness of the spacer 5 is changed, and the spacer 5 is pressed and fixed by the pressing lid 3 for adjustment. The air gap adjustment of the magnetic sensor 10 is performed so that the sensor fixing block 4 fixed to the pressing lid 3 moves in the guide groove 5a of the spacer 5 in the radial direction.
This is performed by moving the holding cover 3 in the radial direction with respect to the spacer 5. By thus moving along the guide groove 5a, the sensor fixing block 4 can be positioned with high accuracy. In this angle detecting device, since the air gap adjusting directions of the two sensors S1 and S2 are different from each other, it is possible to adjust each of them independently. Further, since the two sensors S1 and S2 are not installed on the same plane, the radial dimension of the entire device can be reduced, and one of the sensors S1 and S2 can be reduced.
It is not necessary to reduce the diameter of the detection position of, and the detection positions of both sensors S1 and S2 can be increased. Therefore, it becomes easy to ensure accuracy.

Since the rotating shaft 1 supports the bearing 11 in a preloaded state, even if it is used for a high load such as a construction machine,
The bearing rigidity is high, the influence of the load acting on the rotary shaft 1 on the air gap in each direction is small, and the rotation angle can be accurately detected. The two sensors S1 and S2 are not only made redundant by using two sensors, but one of them is of a contact type and the other is of a non-contact type so that different types of sensors are used. As a result, a large error is less likely to occur in both sensors at the same time, and the accuracy and reliability due to the redundancy can be obtained more reliably. In this embodiment, for example, the rotary shaft 1
Even if the brush 17a is worn by a high load for a long period of time, the accuracy deterioration can be suppressed to a minimum because the other sensor S1 is used together.

In the above embodiment, the sensor S1 having the radial rotation angle detection surface B1 is of the non-contact type and the sensor S2 having the axial rotation angle detection surface B2 is of the contact type. Alternatively, the sensor S1 having the radial rotation angle detection surface B1 may be of the contact type, and the sensor S2 having the axial rotation angle detection surface B2 may be of the non-contact type. Further, the number of sensors S1 and S2 is not limited to one for each of the rotation angle detection surfaces B1 and B2 in the radial direction and the axial direction, but two or more may be provided.

[0014]

In the angle detecting device of the present invention, the two sensors have different air gap adjustment directions, so that the respective adjustments can be made independently and the air gap adjustment becomes easy. Also, because the two sensors are not installed on the same surface,
The size in the radial direction can be reduced, and the entire device can be downsized.
Further, since it is not necessary to reduce the diameter of the detection position of one sensor and the detection positions of both sensors can be made large, it is easy to ensure accuracy. When a plurality of bearings that support the rotating shaft are provided and these bearings are preloaded, the rigidity of the bearing is increased and even if a large load is applied to the rotating shaft,
The influence on the air gap is small and the rotation angle can be detected accurately. Therefore, it is suitable for high loads. When the sensor having the rotation angle detection surface in the axial direction is a contact type sensor and the sensor having the rotation angle detection surface in the radial direction is a non-contact type sensor, one of the two sensors is selected. When one is a contact type sensor and the other is a non-contact type sensor, the effect of ensuring accuracy and reliability due to redundancy is further enhanced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an angle detection device according to an embodiment of the present invention.

FIG. 2 is a back view of the angle detection device.

FIG. 3 is a perspective view showing a relationship between the spacer and a sensor fixing block.

FIG. 4 is a partially exploded perspective view of the angle detection device.

FIG. 5 is a sectional view of a conventional example.

FIG. 6A is an explanatory view of one of the rotation angle detection surfaces,
(B) is an explanatory view of the other rotation angle detection surface.

[Explanation of symbols]

1 ... Rotary shaft, 2 ... Housing, 3 ... Pressing lid (lid), 4
... Sensor fixing block, 5 ... Spacer, 6 ... Bearing retainer,
7 ... back plate, 9 ... magnetic drum, 9a ... magnetic band,
10 ... Magnetic detector, 11 ... Bearing, 12, 13 ... Spacer, 1
4 ... Signal processing circuit device, 16 ... Resistor forming body, 16a ...
Resistor, 17 ... Brush assembly, 34 ... Sealing resin, B
1, B2 ... Rotation angle detection surface, S1, S2 ... Sensor

Claims (3)

[Claims] 1. Two sensors are installed between a housing and its lid and a rotating shaft supported by bearings in the housing, and one of the sensors has a rotation angle detection surface in the axial direction of the rotating shaft. The other sensor is an angle detection device in which a rotation angle detection surface is provided in the radial direction. 2. The angle detection device according to claim 1, wherein a plurality of the bearings are provided and the bearings are preloaded. 3. The angle detection device according to claim 1, wherein one of the two sensors is a contact sensor, and the other sensor is a non-contact sensor.