JPH0447614Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a high-resolution magnetic rotary encoder used to detect the rotation angle, speed, direction, etc. of rotating parts of printers, robots, NC machines, etc. .

(Prior Art) Conventionally, optical rotary encoders have been the mainstream, but recently magnetic rotary encoders have attracted attention because of their improved frequency response, improved ambient temperature range, and lower cost. The magnetic rotary encoder is configured as follows. A magnetic recording medium is coated on the circumference of a rotating drum, and magnetic writing is performed by alternately reversing the direction of magnetization on the coated magnetic recording medium at predetermined pitches. The magnetic flux of such a magnetic writing portion is read by a magnetic sensor placed close to the magnetic recording medium. A particularly important part in such a magnetic rotary encoder is the positional relationship between the circumferential surface of the rotating magnetic recording medium and the magnetic sensor, and the gap length, relative angle, etc. greatly affect the readout output level. For this reason, the mechanism for fixing and adjusting the position of the magnetic sensor is an important element of the magnetic rotary encoder.

An example of a conventional magnetic rotary encoder is shown in FIG. 6, and an exploded perspective view thereof is shown in FIG. 7. A rotating drum 2 having a magnetic recording medium 3 coated on its outer peripheral surface.
is rotatably attached to the fixed base 1 via a rotating shaft 21. On the other hand, the magnetic sensor column 4 to which the magnetic sensor 5 is attached is located in the groove 1 provided in the fixed base 1.
1 and is fixed with a fixing screw 6. 7 is a bearing.

(Problem to be Solved by the Invention) The gap length between the magnetic sensor 5 and the magnetic recording medium 3 can be adjusted by using the screw insertion hole 41 provided in the magnetic sensor column 4 as an elongated hole. This is realized by making the fixed base 1 movable in the radial direction. That is, after adjusting it by moving it in the radial direction while fitting the groove 11 of the magnetic sensor column 4,
Fix with screw 6 at the optimum position. In this way, the only adjustment possible in the conventional magnetic rotary encoder is the adjustment of the gap length in the radial direction, and the adjustment of the angle in the circumferential direction between the magnetic sensor 5 and the circumferential surface of the magnetic recording medium 3; It is impossible to adjust the angle of the two surfaces of the rotating drum in the thickness direction. Therefore, if the magnetic sensor 5 is misaligned in the surface direction due to uneven adhesion at the time of adhesion of the magnetic sensor 5 to the pillar 4,
The disadvantage is that the readout output is reduced and the margin for conversion to pulses is narrowed. Further, machining the groove 11 on the fixed base 1 increases the number of man-hours, which increases the cost of the fixed base 1.

An object of the present invention is to provide a magnetic rotary encoder that can realize stable output characteristics by using a magnetic sensor position adjustment mechanism as a mechanism that has a gap length and angle adjustment function.

The invention also aims to provide a low-cost magnetic rotary encoder with simple component geometry.

(Means for Solving the Problems) According to the present invention, the magnetic sensor support is composed of a plate part for mounting the magnetic sensor and a pedestal part for fixing to a fixed base, and the pedestal part has a plate part for fixing the magnetic sensor support to the fixed base. A screw hole into which a screw for adjusting the position of the magnetic sensor support can be inserted is provided. On the other hand, the fixed base is provided with a disc-shaped pedestal for attaching the magnetic sensor column, and the magnetic sensor column is attached to the pedestal with a fixing screw, and its position is adjusted with a position adjustment screw. In this way,
The gap length and angle between the magnetic sensor and the surface of the magnetic recording medium can also be adjusted to provide a magnetic rotary encoder with stable output characteristics.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 5.

FIG. 1 shows a perspective view of an embodiment according to the present invention;
FIG. 2 is an exploded perspective view thereof. A magnetic recording medium 3 is coated on the circumference of the rotating drum 2, and magnetic writing is performed on the magnetic recording medium 3 at predetermined pitches. The rotating shaft 21 is rotatably attached to the fixed base 1 via a bearing 7 fitted into the center hole of the fixed base 1. On the other hand, the magnetic sensor support column 8 consists of a plate portion 81 and a pedestal portion 82.
A magnetic sensor 5 is attached using adhesive or the like. The pedestal portion 82 also includes fixing screw insertion holes 83 and 84 and position adjustment screw holes 8.
5 and 86 are provided, respectively. The fixing base 1 is provided with a cradle 9 for fixing the magnetic sensor column.
The cradle 9 has screw holes 91, corresponding to the insertion holes 83, 84 drilled in the pedestal 82 of the magnetic sensor column 8.
92 is provided. Since the pedestal 9 is formed concentrically with the fixed pedestal 1, the number of processing steps is shortened and the cost is low. The magnetic sensor column 8 is attached to the screw hole 9 of the pedestal 9 by fixing screws 61 and 62.
The magnetic sensor 5 is fixed at the position corresponding to 1 and 92, but the magnetic sensor 5 is
The gap length and angle between the magnetic recording medium 3 and the magnetic recording medium 3 are adjusted.

Figure 3 is a side view of the example in Figure 1,
Adjustment screws 71 and 72 adjust the gap length d between the magnetic sensor 5 and the magnetic recording medium 3. The range of adjustment values is typically between 50μ and 100μ. On the other hand, by adjusting the screwing depth of the fixing screws 61 and 62, the relative angle between the magnetic sensor 5 and the thickness direction surface of the magnetic recording medium 3 can be adjusted. Typically, the relative angle is adjusted to 180°.

FIG. 4 is a diagram of the example shown in FIG. 1 viewed from the left side of the rotating drum 2. FIG. By tightening the adjustment screws 71 and 72, the angle of the magnetic sensor column 8 with respect to the fixed base 1 in the circumferential direction is adjusted, that is, the relative angle θ between the magnetic sensor 5 and the magnetic recording medium 3 is adjusted. Typically, the angle θ is adjusted to 180°.

As described above, the magnetic sensor column adjustment mechanism according to the present invention has a simple configuration using fixing screws 61, 62 and position adjustment screws 71, 72, but
The gap length and angle of the magnetic sensor 5 can be easily adjusted. As a result, as shown in FIG. 6, the output characteristics are significantly improved compared to the case where only the air gap is adjusted, and a magnetic rotary encoder with stable output can be realized. The shape of the fixed base 1 is also simpler than the conventional fixed base, and a low-cost magnetic rotary encoder can be realized.

FIG. 5 shows another embodiment of the present invention, in which the rotating shaft 2
1, a rotary drum 2' for zero point detection is installed in parallel with the rotary drum 2. A magnetic recording medium 3' is formed at one location on the outer peripheral surface of the rotating drum 2'. Further, a magnetic sensor column 8' to which a magnetic sensor 5' is attached is added as a means for detecting the magnetized magnetic recording medium 3'.

(Effects of the invention) As described above, according to the invention, the gap and angle of the magnetic sensor can be adjusted with a simpler configuration than the conventional one, and it has much more stable output characteristics than the conventional one. We can provide low-cost magnetic rotary encoders.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the magnetic rotary encoder according to the present invention, Fig. 2 is an exploded perspective view of Fig. 1, Fig. 3 is a side view of Fig. 1, and Fig. 4 is a view seen from the left side of Fig. 1. , FIG. 5 is a perspective view of another embodiment of the present invention, FIG. 6 is a perspective view of a conventional magnetic rotary encoder, and FIG. 7 is an exploded perspective view of FIG. 6. 1...Fixed base, 2...Rotating drum, 3...Magnetic recording medium, 4, 8...Magnetic sensor column, 5, 5'
...Magnetic sensor.

Claims (1)

[Scope of utility model registration request] A fixed base, a rotating drum that is rotatably attached to the fixed base via a rotating shaft and has an outer peripheral surface that is magnetized with the direction of magnetization alternately reversed at a predetermined pitch, and a magnetic sensor. In a magnetic rotary encoder having a magnetic sensor column arranged to face the outer circumferential surface of the rotating drum, the magnetic sensor column has a plate portion for fixing the magnetic sensor and a pedestal portion for fixing to the fixing base. The pedestal part is provided with at least two holes lined up in the direction of the rotation axis through which the screws for fixing the magnetic sensor support can be inserted, and the magnetic sensor gap and angle adjustment with respect to the outer peripheral surface of the rotating drum are provided. At least two screw holes into which screws can be inserted are arranged so as to be lined up with an imaginary line connecting the two holes in between, and the fixing base is provided with a cradle for fixing the magnetic sensor column. . A magnetic rotary encoder, characterized in that the gap and angle are adjustable via the magnetic sensor column.