JPH0228457Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rotation direction detection sensor that detects the rotation direction of a rotating body.

[Conventional technology]

Methods for detecting the rotational direction of a rotating body include (1) a method that uses mechanical frictional force, (2) a method that processes and detects the phase shift of multiple detection signals using an electronic circuit such as a flip-flop, and (3) ) There are methods such as using a DC generator.

[The problem that the idea aims to solve]

By the way, method (1) mentioned above has a problem in terms of durability, method (2) has a complicated circuit and increases cost, and method (3) has a problem with durability of the brush. There was a problem.

Therefore, one permanent magnet is attached to a non-magnetic rotor that rotates as the rotating body rotates, and a reed switch that turns on and off as the permanent magnet rotates is placed on the outer periphery of the rotor. A rotational direction detecting device provided with a permanent magnet (for bias) for applying magnetic flux to a switch in advance has been published as Japanese Utility Model Publication No. 51-34313.

This device outputs pulse signals and DC signals separately depending on the rotational direction of the rotor, so it has the advantage that the rotational direction can be easily determined and the circuit configuration can be simplified. but,
A permanent magnet that biases the reed switch
Since it is provided on the reed switch side, the adjustment element must be designed and adjusted by taking into account the strength of the magnetic field on both the rotating and stationary sides, which poses the problem of making this work extremely troublesome. Ta.

[Purpose of invention]

This invention was developed by focusing on the above-mentioned drawbacks, and by forming a bias permanent magnet on the rotor side that biases the reed switch, the rotation direction can be easily designed and adjusted. The purpose is to provide a detection sensor.

[Example of idea] Next, embodiments of the present invention will be described with reference to the drawings.

Figures 1 and 2 show a first embodiment using a reed switch with hysteresis and a permanent magnet.
Fig. 1 shows a configuration diagram, and Fig. 2 shows a timing chart. 1 is a rotor that rotates with the rotation of a rotating body (not shown), and 2a and 2b are spaced at 90 degrees on the outer circumference of the rotor 1. The reed switches 3a to 3h are eight permanent magnets buried in the rotor 1, and the two permanent magnets 3a and 3e, which are arranged at an interval of 180 degrees, are The six permanent magnets 3b to 3d and 3f to 3h, which are buried close to the outer circumferential surface of the rotor 1 and arranged at equal intervals between the permanent magnets 3a and 3e, have their tips slightly away from the outer circumference of the rotor 1. It is located inward and buried. The permanent magnets 3a to 3d are magnetized so that the outer circumferential surface of the rotor 1 has a north pole, and the permanent magnets 3e to 3h have an south pole, and each acts as a bias.

By connecting the reed switches 2a and 2b described above in parallel and applying a voltage to both ends thereof to rotate the rotor 1, an output as shown in FIG. 2 can be obtained. That is, if the rotor 1 is now rotated in the direction of the solid arrow, the reed switch 2a in FIG.
is excited and turned on by the lines of magnetic force of the permanent magnet 3a. That is, since the permanent magnet 3a is embedded in the outermost periphery of the rotor 1, its lines of magnetic force are large, and therefore the reed switch 2a is turned on under the influence of the lines of magnetic force. When the rotor 1 further rotates and the permanent magnets 3b to 3d pass the reed switch 2a, the hysteresis of the reed switch 2 maintains the on state. Further, the reed switch 2b is connected to the permanent magnet 3e by the rotation of the rotor 1.
When the reed switch 2a passes, it is turned on by a strong line of magnetic force from the permanent magnet 3e, as in the case of the reed switch 2a, and is kept in the on state by the rotation of the rotor 1 while the permanent magnets 3f to 3h pass.

When the permanent magnet 3e passes through the reed switch 2a, a magnetic field in the opposite direction to that in the holding state acts on the reed switch 2a, so that the reed switch 2a is once demagnetized and turned off, and then is excited with the opposite polarity and turned on. The on state is maintained while the permanent magnets 3f to 3h are passing due to further rotation of the rotor 1.

On the other hand, when the permanent magnet 3a passes through, the reed switch 2b is also opened at one end and is excited with the opposite polarity to turn on, and is maintained in the on state by the permanent magnets 3b to 3d.

Thereafter, since the above-described operations are repeated, each reed switch 2a and 2b will be in a state as shown in FIG. 2a. Therefore, when the reed switches 2a and 2b are connected in parallel, the rotor 1 continues to be turned on while rotating, and a DC waveform output is sent out.

Next, a case will be described in which the rotor 1 is rotated in the direction of the chain arrow.

When the permanent magnet 3a approaches the reed switch 2a, the reed switch 2a turns on, but when the rotor 1 rotates and the permanent magnet 3h approaches, a magnetic field opposite to the magnetic field when the reed switch is turned on acts, so the reed switch 2a turns on. 2a is turned off, and this state continues until permanent magnet 3e approaches. When the permanent magnet 3e approaches the reed switch 2a, it is excited with the opposite polarity and turned on. However, when the rotor 1 rotates and the permanent magnet 3d approaches, the reed switch 2a is turned off again due to the action of a magnetic field opposite to that described above, and this state is maintained until the permanent magnet 3a approaches.

On the other hand, like the reed switch 2a, the reed switch 2b is turned on momentarily and then turned off for a long time.

Therefore, the state is as shown in FIG. 2b, and both outputs of the two reed switches 2a and 2b are switched on and off and have a pulse waveform, so depending on the rotation direction of the rotor 1, a DC waveform and a pulse waveform are output. Therefore, the direction of rotation can be easily detected.

FIG. 3 shows a second embodiment, in which the rotor 1 is provided with one permanent magnet 3a for turning on the reed switch 2, and one permanent magnet 3b for keeping the reed switch 2 turned on.

In this embodiment, when the rotor 1 rotates in the direction of the solid arrow, the reed switch 2, which is turned on by the permanent magnet 3a, continues to be turned on by the permanent magnet 3b. It stays on for a few seconds.

On the other hand, when the rotor 1 rotates in the direction of the chain arrow, the reed switch 2 turned on by the permanent magnet 3a immediately turns off because there is no permanent magnet to maintain the on state when the rotor 1 rotates.

Therefore, the waveforms of reed switch 2 are as shown in Fig. 2a,
As shown in b, the waveform has a long on-time and a short waveform depending on the rotational direction of the rotor 1, so the rotational direction can be easily detected.

5 to 7 show a third embodiment in which four reed switches 2a to 2d are arranged at 90 degree intervals around the outer circumference of the rotor 1, and the first and second reed switches described above are arranged on the rotor 1.
Three regions are formed: a region 3a for turning on each reed switch similar to that in the embodiment, a region 3b for turning off the reed switch, and a bias region 3c for keeping the reed switch turned on by utilizing the hysteresis of the reed switch. be. Note that the on region 3a and the off region 3b are formed for each 90 degrees of the rotor 1, and the bias region 3c is formed for 180 degrees.

Then, as shown in FIG. 6, the reed switches 2a to 2d described above are connected in parallel with 2a and 2b and 2c and 2d in parallel, and the parallel circuits are connected in series to rotate the rotor 1 in the direction of the solid arrow. By the same operation as in the first and second embodiments described above, the waveform as shown in FIG.
obtained by. Here, reed switch 2
a, 2b first parallel circuit and reed switch 2
In the second parallel circuits c and 2d, neither the reed switches 2a and 2b of the first parallel circuit nor the reed switches 2c and 2d of the second parallel circuit are in the on state at the same time, so between IN and OUT Turns off.

Furthermore, when the rotor 1 is rotated in the direction of the chain arrow, a waveform as shown in FIG. 7b appears at each reed switch 2a.
~2d. That is, when either reed switch 2a or 2b of the first parallel circuit is in the on state, reed switch 2 of the second parallel circuit is turned on.
c, 2d is in the on state, and reed switch 2a, 2b or 2 of each parallel circuit is in the on state.
Since either one of c and 2d is always in the on state, it is always in the on state between IN and OUT.

FIG. 8 shows a fourth embodiment in which the rotor 1 shown in FIG. 5 is used and two reed switches 2a and 2b are connected as shown in the figure. When rotated, 2 in Figure 9a
The reed switches 2a and 2b are turned on and off as indicated by the reed switches 2a and 2b.Therefore, since there are times when neither of the reed switches 2a and 2b are on at OUT1, the output appears only at this time, that is, the 9th Diagram a
The pulse output of OUT1 appears. On the other hand, OUT2
Since the reed switches 2a and 2b are not turned on at the same time, an output appears at any time, that is, the DC output of OUT2 in FIG. 9a appears.

Similarly, when rotor 1 rotates in the direction of the chain arrow, 2a and 2b in Fig. 9b turn on and off, so no output appears at OUT1, and
Pulse output appears on OUT2.

In the above embodiment, the on/off control of the reed switch is performed using a permanent magnet, but this may be replaced with an electromagnet, or the rotor 1 may be made of a magnetic material, for example, as shown in FIG. It is also possible to magnetize it like this.

[Effect of idea]

As described above, the present invention has a permanent magnet that turns on the reed switch and a permanent magnet that holds the turned on reed switch in the on state in a rotor that rotates forward and backward. By being able to obtain a corresponding output and having a completely different output, it is possible to easily and reliably determine the direction of rotation, and a permanent magnet is installed on the rotor side to keep the sensor in the ON state. Therefore, the structure is simple and can be manufactured at low cost.

[Brief explanation of the drawing]

The figure shows an embodiment of the rotational direction detection sensor according to the present invention, Figures 1, 3, and 5 are explanatory diagrams showing the configuration, and Figures 2, 4, 7, and 9 are implementation examples of the rotation direction detection sensor of the present invention, respectively. FIG. 6 is a circuit diagram showing the connection of the reed switch in the embodiment of FIG. 5, and FIG. 8 is another circuit diagram showing the connection of two reed switches in the embodiment of FIG. 5. . 1, 6... Rotor, 2, 2a to 2d... Reed switch, 3a to 3h... Permanent magnet.

Claims (1)

[Scope of utility model registration request] at least one reed switch; a rotor that rotates in forward and reverse directions and arranged at a slight distance from the reed switch; and at least one rotor formed on the outermost surface of the rotor to turn on the reed switch. a permanent magnet, and at least one permanent magnet that is formed inside the permanent magnet of the rotor and that maintains the on state of the reed switch that has been turned on, and that the reed switch A rotation direction detection sensor characterized in that the on-times of the rotation direction detection sensors are different.