JPH076721U - Rotation angle detector - Google Patents

Abstract

(57) [Summary] [Purpose] It should be possible to use it without the need for a shaft joint installation space around it, and to detect angles accurately even if some displacement or force occurs on the shaft on the detected side. It is applied to rotary encoders and potentiometers. [Structure] The input shaft 1 has an angle detection rotor 2 fixed at one end and is rotatably supported by two bearings 3. The angle detecting rotor 2 is a disk scale having a large number of slits 9 radially provided on the outer periphery thereof, and a light emitting element and a light receiving element are provided on both sides of the slit forming position. Input shaft 1
Is formed as a hollow shaft, and a flexible shaft coupling 4 is incorporated therein. The shaft joint 4 is of the Oldham coupling type and is composed of a transmission member 5 formed on the shaft 8 on the detected side, an intermediate member 6, and a driven member 7. The intermediate member 6 engages with the engaging grooves 6a and 6b orthogonal to the members 5 and 7 on both sides,
The driven member 7 is integrally fixed to the input shaft 1. Shaft joint 4
A bellows coupling or the like can also be used for this.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotation angle detecting device such as an optical or magnetic rotary encoder or a potentiometer.

[0002]

[Prior art]

 Conventionally, an optical rotary encoder shown in FIG. 3 has been used as a device for detecting a rotation angle. In this, the radial slit 53 of the disc scale 52 attached to the input shaft 51 is photoelectrically read by the light source 54 and the light receiving element 55, and the rotation angle is detected. A fixed index scale 56 is provided in front of the light receiving element 55. The input shaft 51 is supported by two rolling bearings 57, 57, and is usually connected to the shaft 58 on the detected side by a flexible shaft joint (not shown) or the like. Therefore, even if the shaft 58 on the detected side is displaced, the input shaft 51 is neither displaced nor subjected to a force.

[0003]

[Problems to be solved by the device]

 However, there is a case where the shaft 58 on the detected side and the input shaft 51 are connected without using a shaft coupling due to space limitations. In such a case, the input shaft 51 is displaced or receives a force. Therefore, the disc scale 52 is also displaced, and the detected rotation angle may include an error.

The object of the present invention is to use without requiring a space for installing a shaft coupling in the periphery, and to accurately detect an angle even if some displacement or force is generated on the shaft on the detected side. It is to provide a device.

[0005]

[Means for Solving the Problems]

 In the rotation angle detecting device of the present invention, an input shaft, which is provided with a rotor for angle detection and is rotatably supported by a bearing, is a hollow shaft, and a shaft on the detection side is connected to the input shaft. Is provided inside the input shaft. The shaft coupling shall be able to absorb eccentricity and declination.

[0006]

[Action]

 With this configuration, the rotation of the shaft on the detected side is transmitted to the input shaft via the built-in shaft coupling. In this case, even if the shaft on the detected side is slightly displaced or a force other than the rotational direction is applied, these displacements and forces are absorbed by the shaft coupling, and only the rotational displacement is transmitted to the input shaft. Therefore, the accurate rotation angle can be detected, and it also helps prevent damage to the rotation angle detection device. In addition, since the shaft joint is built into the input shaft, there is no need to install a shaft joint outside, and it can be used in places where the space for installing the shaft joint cannot be obtained.

[0007]

【Example】

 An embodiment of this invention will be described with reference to FIGS. This embodiment is an example applied to an optical rotary encoder. An angle detecting rotor 2 is fixed to one end of the input shaft 1 and is rotatably supported by two bearings 3 such as a deep groove ball bearing with a seal. The angle detecting rotor 2 is a disc scale having a large number of slits 9 radially provided on the outer periphery thereof, and a light emitting element and a light receiving element are arranged on both sides of the slit forming position. The input shaft 1 is formed as a hollow shaft, and a flexible shaft joint 4 is built therein.

The shaft joint 4 is of the Oldham coupling type and is composed of a transmission member 5 formed on the shaft 8 on the detected side, an intermediate member 6, and a driven member 7. Each of the members 5 to 7 is a round shaft having a diameter slightly smaller than the inner diameter of the input shaft 1, and the driven member 7 is integrally fixed to the input shaft 1. The intermediate member 6 has a pair of engagement grooves 6a and 6b provided on both end surfaces thereof at right angles to each other. It is formed on the member 5 and the driven member 7. The shaft 8 on the detected side is rotatably supported by another device and has its tip inserted into the input shaft 1 of this rotation angle detecting device. It is movably accommodated in the input shaft 1 by being engaged with the engaging grooves 6a and 6b.

With this configuration, the rotation of the shaft 8 on the detected side is transmitted to the input shaft 1 via the built-in shaft coupling 4, and the rotor 2 for angle detection rotates. In this case, the intermediate member 6 of the shaft coupling 4 can freely move in the radial direction inside the input shaft 1 while being engaged with the two engaging grooves 6a and 6b orthogonal to the members 5 and 7 on both sides. . Therefore, even if the shaft 8 on the detected side is eccentric or declined with respect to the input 1, or if a force other than the rotational direction is applied, these displacements and forces can be freely moved by the intermediate member 6. Only the rotational displacement is absorbed and transmitted to the input shaft 1. Therefore, the accurate rotation angle can be detected, and it also helps prevent damage to the rotation angle detection device. Further, since the shaft coupling 4 is built in the input shaft 1, it is not necessary to provide the shaft coupling externally, and the shaft coupling can be used in a place where the space for installing the shaft coupling cannot be obtained in the periphery.

Although the Oldham coupling is used as the built-in shaft coupling 4 in the above-mentioned embodiment, a bellows coupling or other various flexible shaft couplings can be used. Further, although the above embodiment has been described with respect to the case of being applied to the optical rotary encoder, the present invention can be applied to a rotation angle detecting device in general. For example, a magnetic encoder in which the angle detecting rotor 2 is provided with a magnetic scale, a potentiometer in which a brush type angle detecting rotor is provided in the input shaft 1 instead of the disc type angle detecting rotor 2, and the like. Can also be applied to.

[0011]

[Effect of device]

 In the rotation angle detecting device of the present invention, since the input shaft has a hollow shaft joint and is capable of absorbing eccentricity and declination, the input shaft has a built-in shaft joint. Even if some displacement or force is generated on the shaft on the detected side, angle detection can be performed accurately.

[Brief description of drawings]

FIG. 1 is a cutaway perspective view of an embodiment of the present invention.

2A is a plan view of the shaft coupling, FIG. 2B is a front view of the same, and FIG. 2C is a sectional view taken along line CC of FIG.

FIG. 3 is a perspective view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Input shaft, 2 ... Angle detection rotor, 3 ... Bearing, 4 ... Shaft coupling, 5 ... Transmission member, 6 ... Intermediate member, 6a, 6b ... Engaging groove, 7 ... Follower member

Claims (1)

[Scope of utility model registration request] 1. An axis capable of absorbing an eccentricity and an eccentricity, in which an input shaft rotatably supported by a bearing is provided with a rotor for detecting an angle is a hollow shaft, and a shaft on a detection side is connected to the input shaft. A rotation angle detection device in which a joint is provided inside the input shaft.