JPS61122517A - Rotary encoder - Google Patents

Abstract

PURPOSE:To simplify structure, to minimize the influence of backlash, and to improve measurement precision and resolution by converting the rotation of a contact wheel into the rotation of a shaft perpendicular to said wheel and providing numbers of magnetic bodies at the outer periphery of the shaft. CONSTITUTION:A bevel gear 6 fixed coaxially with the contact wheel 1 which profiles a necessary route on a drawing such as a map and another bevel gear 7 engaging said gear are used in combination to convert the rotation of the contact wheel 1 into the rotation of the shaft 8 perpendicular to the contact wheel 1. Many magnetic bodies 9 are provided at axially different positions of the outer periphery of the shaft 8 where the radial phase shifts by, for example, 40 deg., and magnetic sensors 10 corresponding to the magnetic bodies 9 are arranged closely along the shaft 8, thereby counting an AND result among outputs of the respective sensors 10. The resolution is determined by the diameter of the shaft 8 and the phase pitch of the magnetic bodies 9, but the pitch is selected relatively freely by varying the length of the shaft properly, so an encoder is increased in resolution greatly which the size except the length is held constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotary encoder, and particularly to an encoder with improved resolution for detecting the amount of rotation of a rotating body.

(Prior Art) Conventionally, a rotary encoder that converts the amount of rotation of a nine-rotating body into a digital amount and counts distance, nine rotation angles, etc. has been widely used.

Such an encoder rotates the contact wheel 1 along a desired path such as a map as shown in 2, for example, IE Z (at and (bl), and calculates the amount of rotation by an intermediate gear 2 integral with the contact wheel 1 and the The signal is transmitted to the encoding disc 4 integrated with the gear 3 through the reduction gear 3 that meshes with the disc 4.
The contact is detected by counting a large number of magnetic bodies, slits, or marks provided at a required pitch p on the periphery using a magnetic sensor or an optical sensor 5 that combines a light-emitting element and a light-receiving element. It measures distances on a map based on the amount of rotation of the wheel.

However, in order to improve the reading accuracy of the encoder as described above, since there is a reading limit in the density of the pitch p of the marks on the encoding disk 4, the disk 4 should be made with a large diameter to increase the number of marks. Alternatively, it is necessary to make the disc 4 small in diameter and reduce the number of marks, and to set its rotational speed sharply. In either case, a large number of gears must be combined, making the structure complex and the back of the gears. There is a defect in that the effects of rush accumulate and cause variations in measurement accuracy, and this defect is particularly severe in the case of a pen-type encoder. The object of the present invention is to provide an encoder which has a simplified structure and minimizes the influence of backlash, thereby reducing variations in constant accuracy and improving resolution.

(Summary of the invention) In order to achieve the above-mentioned object, in the present invention, l
The rotation of the contact shaft is converted into the rotation of an axis perpendicular to the rotation of the contact shaft, and a large number of magnetic or optical marks are attached to the outer periphery of the shaft with different radial phases and axial positions, and each of these marks is marked individually. It is something.

(Examples) The present invention will be described in detail below using nine examples shown in the drawings.

FIG. 1 (al and (bl) are a side view and a plan view, respectively, illustrating the principle of the encoder according to the present invention.

In this figure, the rotation of the contact shaft 1 is made perpendicular to the required path 1 on a map or other diagram by combining a bevel gear 6 that is coaxially fixed to the contact shaft 1 and another bevel gear 7 that meshes with it. The rotation of the axis 8 is converted into the rotation of the axis 8. On the outer periphery of the shaft 8, magnetic bodies 9, 9 . ... are provided along the axis 8, and the magnetic bodies 9, 9. ...
. . . An array 1Ot of magnetic cells corresponding to the respective sensors 1O is arranged close to each other, and the logical sum of the outputs of the respective sensors 1o is counted.

By doing this, the contact width 10 rotation amount is reduced to the shaft 8.
Magnetic material 9, 9. ...It becomes possible to display the total number of detected counts. The resolution is determined by the diameter of the shaft 8 and the phase pitch of the magnetic material, but this pitch can be relatively freely selected by appropriately expanding or contracting the length of the shaft, so this encoder The total resolution can be greatly increased while keeping all other dimensions constant except for its length. In addition, since only one set of bevel gears is sufficient as a mechanical element for making the two rotational axes t perpendicular to each other, the effects of backlash can be kept to a minimum, so that the measurement accuracy does not deteriorate at all.

In order to minimize the overall size of the rotary encoder according to the present invention, it may be configured as follows.

That is, as shown in FIG. 3, a recess may be provided in the center of the contact shaft 1, and the core portion may be an internal bevel gear 19, which meshes with the gear 7 fixed to @8. By doing so, it is possible to bring the rotating surface of the contact shaft 1 and the center line of the shaft 8 as close as possible, thereby reducing the diameter of the entire encoder.

The above description has only been made on the case where the rotational axes of the contact shaft 1 and the shaft 8 are orthogonal to each other, but they do not necessarily have to be orthogonal to each other, and depending on the purpose of use, the intersection angle between the two rotational axes may be more obtuse than 90 degrees. good. In such cases, it is also possible to change the direction of the rotating shaft by using a flexible 7-bull φ shaft as shown in Figure 4. In this case, mechanical errors such as backlash are further reduced and measurement accuracy is improved. (It is obvious that this will help.

Further, in the above-described embodiment, only the combination of the magnetic body and the magnetic sensor was described, but it goes without saying that this can be replaced with an optical sensor, so a detailed description is omitted to avoid complexity.

It is also possible to reduce the number of detection elements by changing the structure of the mark, such as a lock or a magnetic material attached around the shaft, to a length that can encode the entire position on the shaft.

(Effects of the Invention) Since the present invention is constructed as described above, there is almost no need to consider the beaches of magnetic materials or optical marks as in conventional rotary encoders, so that Since no special measures are required to increase or decrease the rotational speed of the intervening intermediate member, the structure is simple, which not only facilitates miniaturization, but also minimizes variations in measurement accuracy due to mechanical play. At the same time, the magnetic type has the effect of greatly improving its resolution simply by increasing the number of optical cells.

9 The rotary encoder according to the present invention requires a larger number of magnetic or optical sensors than the conventional one, so it seems likely that the cost will increase. Therefore, whether one piece is torn or a large number of pieces are manufactured in an array, the cost is almost the same and can be absorbed by simplifying the mechanism.

[Brief explanation of the drawing]

Figure 1 (at and (bl) respectively indicate the rotary motor according to the present invention.
FIG. 2 is a side view and a plane configuration diagram showing the basic configuration of the encoder, and FIG.
', IE3o and Brush4 are side sectional views showing different embodiments of the present invention. 1...Rotating body (contact ring), 8...
······shaft. 9...Magnetic material (or optical mark). 10...Magnetic (or optical) center. Patent applicant: Toyo Tsushinki Co., Ltd. Figure 2

Claims (1)

[Claims] It is equipped with a mechanism for mechanically converting the amount of rotation of a rotating body into the amount of rotation of a shaft tilted at a required angle with respect to said rotating body. A magnetic material or optical mark is attached, and magnetic or optical sensors corresponding to the respective positions of the magnetic material or optical mark are arranged along the axis, and the amount of rotation of the rotating body is detected by the output of each sensor. A rotary encoder characterized by