JPS594247Y2 - Fixed position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixed position detector, particularly a coaxial origin detector suitable for magnetic scale devices and the like.

Incremental digital magnetic scale devices are widely used in various fields because, as is well known, they can provide a zero-set or preset function at any position, and can be made compact and inexpensive. ing.

However, if there is an accident such as a power outage during use, the position information obtained by the magnetic scale device will be lost, so conventionally, for example, batteries are prepared as a backup power source, and the above position information is counted. Various methods have been considered, such as providing a counter with a memory function, and are already at the stage of practical application.

As a means of solving the above problem, the inventor of the present invention previously proposed incorporating an absolute origin detector using a magnetic sensor into the magnetic scale device. The device is easily affected by external magnetic fields,
It was found that the origin position signal sometimes became unstable, and there was still room for improvement.

In order to improve the above-mentioned problems of the prior art, the present invention has at least two saturable core parts arranged in substantially the same plane position, and the first and second saturable core members are sandwiched between magnetic yokes. , a detection coil is provided in each saturable core portion of the core member, two sets of coaxial magnetic heads are formed at a predetermined interval, and a detection coil is provided in each saturable core portion of the core member, and two sets of coaxial magnetic heads are formed at a predetermined interval. Fixed position detection configured to allow displacement.

The present invention will be described below with reference to embodiments shown in the drawings.
In Figures 1 and 2, 1, 2 and 3 are the first,
The second and third magnetic yokes, 4 and 5 are the first and second magnetic yokes, respectively.
Saturable core member, 6 is a shield case, 7 and 7' are spacers, 8 is a rod-shaped magnet, 9 and 10 are detection coils, 11 is a base made of pure iron, 12 is a screw hole, and 13 is a detection coil extraction hole. , 14 are through holes of the magnetic body 8.

Thus, the saturable core member 4 has two parts, for example, as shown in FIG.
The saturable core parts 4-1 to 4-4, which are larger than the legs, are arranged at approximately the same position, and each core part has a detection coil 9-1 to 9-4.
4 is wound.

The saturable core member 5 also has a similar configuration, and a detection coil 10 is wound around it.

These saturable cores are connected via spacers 7.7' to the first,
It is sandwiched between the second and third magnetic yokes 1, 2.3, and thus two sets of coaxial magnetic heads are formed at a predetermined interval.

These magnetic heads have a rod-shaped magnetizing body 8 that passes through the through hole 14.
It is relatively movable along the

The rod-shaped magnetizing body 8 is magnetized at a predetermined position 15, and if a plurality of fixed position signals are to be obtained at a predetermined interval, it may be magnetized at a plurality of positions.

When the magnetic head is moved relative to the magnetizing body 8 and passes through the magnetized position, two detection voltages e4 and eH as shown in FIG. 3 are obtained in the detection coils 9 and 10.

As can be seen from FIG. 3, each detection voltage becomes zero at a position away from the magnetized position 15, so it is inconvenient to detect the illustrated zero crossing point and use it as the origin or fixed point.

Therefore, one of the two detection voltages, eB, for example, is used as a gate signal, and the other, el, is used as an origin signal.

For this purpose, the detection voltage el is applied to the pulse generator 16 as shown in FIG. 4 to obtain the gate signal g as shown in FIG. 3, which is applied to the gate circuit 17.

Since the detection voltage el is applied to the gate circuit 17,
Output e of gate circuit 17.

contains a position signal, in particular a zero crossing point, which can provide a unique absolute origin, regardless of its detection direction.

To extract the origin signal, use the gate output e as shown in FIG.

Either use it as the differential signal d at the zero crossing point of
Alternatively, a mono-multivibrator (not shown) having a threshold value of about 1 μm width, for example, is connected to the gate output e near this zero crossing point.

Various methods can be used as necessary, such as using the mono multi-signal m obtained by triggering.

As is clear from the above explanation, according to the present invention, the following effects can be obtained by forming the core members 4 and 5 from two or more core parts as described above.

(1) By making the saturable core coaxial and flat, a magnetic gap is formed around the entire magnetizing body, resulting in a magnetic head with higher sensitivity than known planar magnetic sensors.

(2) The coaxial magnet may move in a direction perpendicular to the axis, and even if the magnet moves away from the air gap, it approaches on the opposite side, so there is no change in the magnetic flux as a whole, and with respect to the circular core. Stable output can be obtained without any output changes due to deviation of the output.

(3) Since the saturable core can be made thin and flat, the thickness in the measurement direction is thinner than in conventional planar magnetic heads, allowing the head to be made smaller and more robust.

(4) Since the structure is such that the saturable core is shielded by a magnetic yoke, the shielding effect is large and it is not easily affected by external magnetic fields.

(5) It is possible to provide a small and highly efficient fixed position detector with a simple configuration and extremely little influence from external magnetic fields.

(6) By using the two sets of magnetic heads described above, a unique absolute origin can be detected regardless of the detection direction.

(7) It is possible to obtain a plurality of fixed position signals by magnetizing the magnetizing body to a desired position.

[Brief explanation of the drawing]

1 and 2 are schematic structural diagrams showing one embodiment of the present invention, FIG.
The figure is a block diagram showing an example of a zero-crossing point detection device used in this embodiment. 1.2.3...First, second, and third magnetic yokes,
4, 5...first and second saturable core members, 8...
...Rod magnetizer, 9°10...Detection coil, 15...Magnetized position.

Claims (1)

[Scope of utility model registration request] First and second saturable core members each having at least two saturable core portions disposed substantially in the same plane are sandwiched between magnetic yokes, and a detection coil is attached to each of the saturable core portions of the core members. 2 sets of coaxial magnetic heads are formed at a predetermined interval, and the fixed position is configured such that the coaxial magnetic heads can be relatively displaced along a coaxial magnet that is magnetized at a predetermined position. Detection device.