JPH03181816A - Magnetic linear encoder - Google Patents

Abstract

PURPOSE:To reduce costs by forming a guide shaft of hard magnetic material, magnetizing an outer peripheral surface of the guide shaft by an encoder signal, and providing a detecting means for detecting the encoder signal. CONSTITUTION:A notch 11 is formed at each confronting part in a recess of a supporting member 10. A guide shaft 12 is provided in the notch 11. A car riage 13 is installed between the shafts 12 via rollers 14. Both shafts 12 are made of rigid magnetic material with large strength. Moreover, an encoder signal E (N pole, S pole...) is magnetized to the outer peripheral surface of one of the shafts 12. A sensor 15 is provided confronting to the shaft 12 to which the signal E is magnetized. Since the shaft 12 is formed of rigid magnetic material with high strength, the signal E is magnetized to the outer peripheral surface of the shaft 12, and the sensor 15 is provided at one end of the carriage 13, the shaft 12 can function also as a scaling medium, thereby reducing costs.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a magnetic linear encoder, and particularly to a magnetic linear encoder suitable for a case where a guide shaft also functions as a scale medium.

[Conventional technology]

Traditionally, a magnetic linear encoder, which is a type of linear encoder, is used as a digital servo element in a position sensor for motor control, and is designed to generate a fixed amount of digital code proportional to the movement of the position of a machine axis. It has become. FIG. 3 is a schematic cross-sectional view of a conventional magnetic linear encoder, in which both guide shafts 2 and 2 are supported by a support member 1.
A cow carriage 4 is disposed between them via rollers 3..., and the carriage 4 is guided by both guide shafts 2, 2 and moves straight in the direction of the front and back in the second figure. Further, a scale medium 5 is attached to the lower part of the carriage 4, and a sensor 6 for detecting the scale medium 5 is disposed at the upper part of the support member 1.

[Problem to be solved by the invention]

By the way, in the above conventional magnetic linear encoder, since the scale medium 5 is attached to the carriage 4, there is a problem that the number of parts corresponding to 7747 parts for the scale increases and the cost of parts increases. Furthermore, it is necessary to secure a mounting space for the scale medium 5 in the space formed by the carriage 4 and the support member 1, and there is a problem that there is no room for mounting other parts in this space. The present invention solves the above problems, and provides a magnetic linear encoder that eliminates the need to attach the scale media by making the guide shaft also function as the scale media, thereby reducing the number of parts and cost. For the purpose of providing.

[Means to solve the problem]

In order to achieve the second object, the present invention includes a support member having a U-shaped cross section, and a pair of guide shafts disposed in parallel to each other on opposing inner surfaces of a recessed portion of the support member. ,
a carriage disposed between the two guide shafts via a roller and moved linearly along the axial direction of the two guide shafts; The one guide shaft is formed of a highly hard magnetic material and has an encoder signal magnetized on its outer circumferential surface, and is located at one end of the carriage in the width direction and is magnetized with the encoder signal. The present invention is characterized in that a detection means for detecting the encoder signal is provided on the opposite side.

[Effect]

According to the present invention, at least one guide shaft is made of a hard magnetic material with high strength, and an encoking signal is magnetized on the outer peripheral surface of the guide shaft, so that one guide shaft has the function of conventional scale media. can also be used. As a result, it is no longer necessary to attach scale media to the carriage as in the past, reducing component costs.Furthermore, the space formed by the carriage and support member provides room for mounting other components. It becomes possible to do so.

【Example】

Embodiments of the present invention will be described below based on the drawings. FIG. 1 is a schematic cross-sectional view of the magnetic linear encoder of this embodiment, and the support member 10, which has a substantially U-shaped cross section, has cutout portions 11 and
11 are formed, and guide 7 shafts 12, 12 are arranged in parallel along the longitudinal direction of these notches 11, 11. Further, a carriage 13 is disposed between the guide shafts 12, 12 via rollers 14, 14, 14. The carriage 13 is guided at both ends by guides/yafts 12, and is moved in a straight line along the axial direction of the guide shaft (perpendicular to the plane of the paper in FIG. 2). Both guide shafts 12 are made of a hard magnetic material with high strength, and one of the guide shafts 12
As shown in Fig. 3, the encoder signal E is placed on the outer peripheral surface of the
(N pole, S pole, N pole, S pole...) is configured to be magnetized. In this case, only one guide shirt 12 is magnetized by the encoder signal E. It is also possible to form it from a hard magnetic material. Further, the encoder signal E on the one end side in the width direction of the carriage 13
A sensor 15 is disposed at a location facing one of the guide shafts 12 which is magnetized. The sensor 15 detects the encoder signal E as the one guide shaft I2 moves in a straight line. Therefore, in the magnetic linear encoder of this embodiment, the one guide shaft 12 is made of a hard magnetic material with high strength, and the encoder signal E is magnetized on the outer peripheral surface of the guide shaft. Since the sensor 15 is attached to one end, the one guide shaft 12 can also function as a conventional scale medium. As a result, it is no longer necessary to attach scale media to the carriage as in the past, reducing component costs.Furthermore, the carriage 13
Since it is not necessary to secure a mounting space for the scale media in the space formed by the support member 10 and the support member 10, it becomes possible to create a margin for mounting other components in the space.

【Effect of the invention】

As described above, the present invention includes a support member having a U-shaped cross section, and a pair of guide shafts disposed parallel to each other on each opposing inner surface of the recess of the support member. , a carriage disposed between the two guide shafts via a roller and moved linearly along the axial direction 1'FiI of the two guide shafts, the guide of at least one of the two guide shafts The shaft is made of a hard magnetic material with high strength, and an encoder signal is magnetized on the outer peripheral surface of the one guide shaft, and one end of the carriage in the width direction is magnetized with the encoder signal. Since the detection means for detecting the encoder signal is provided on the side facing the guide shaft, the following effects can be achieved. ■Since the guide shaft can also serve as the function of conventional scale media, it is no longer necessary to attach scale media to the carriage as in the past.
The number of parts can be reduced and the cost of parts can be reduced. ■With the above ■, it is no longer necessary to secure a mounting space for the scale media as in the past, so the space formed by the carriage and the support member can be made to have a margin. It also becomes possible to mount other parts.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a magnetic linear encoder according to an embodiment of the present invention, FIG. 2 is an external view of a guide shaft of this embodiment, and FIG. 3 is a schematic sectional view of a conventional magnetic linear encoder. 10... Support member, 11... Notch,
12... Guide shaft, 13... Carriage, 14... Roller, 15... Sensor (detection means), E... Encoder signal.

Claims (1)

[Claims] A support member having a U-shaped cross section, a pair of guide shafts disposed parallel to each other on opposing inner surfaces of a recessed portion of the support member, and a roller disposed between the two guide shafts. and a carriage that moves linearly along the axial direction of both guide shafts, at least one of the guide shafts is formed of a hard magnetic material with high strength, and the one guide shaft detection means for magnetizing an encoder signal on the outer circumferential surface of the carriage, and detecting the encoder signal on one end side in the width direction of the carriage and on a side facing one of the guide shafts to which the encoder signal is magnetized; A magnetic linear encoder characterized by being provided with.