JPS5838868A - Revolution speed difference indicator - Google Patents

Abstract

PURPOSE:To enable indication of revolution speed difference between rotary members in a mobile argricultural machine or the like, with a simple construction by moving the pointer in response to a difference in currents supplied to multiple coils of a meter. CONSTITUTION:When the rotary shafts 1 and 2 rotate at a same revolution speed, the drive currents 1a and 1b are equal so that the rotation force of permanent magnets due to the coils 14 and 15 are cancelled to allow a pointer 18 to point to zero. When there occurs a difference in revolution speed between the rotary shafts 1 and 2, the current 1a differs from the current 1b so that the magnet 16 is turned in a predetermined direction to move the pointer 18 by an angle theta. Thus, by forming the dial 19 to correspond to the revolution speed difference, the pointer 18 is able to indicate which of the shafts 1 and 2 has a greater revolution speed and the speed difference between the two shafts.

Description

[Detailed Description of the Invention] The present invention relates to a rotation speed difference display device that can directly display the difference in the rotation speed of two rotating axes. A rotation speed difference display device is used that measures slip by detecting the difference in speed.

FIG. 1 is a block diagram of such a conventional rotational speed difference display device. In the figure, 1 is the first rotating shaft that rotates at a rotational speed Na, 2 is a second rotating shaft that rotates at a rotational speed Nb, 3 is a sensor that detects the rotating shaft 10 rotating speeds, and 4 is the rotating shaft 20 rotating speeds. This is a senna that detects. When the rotating shaft 1.2 rotates, the sensor 3.4 detects rotation signals of frequencies fa and fbO, and these signals are shaped into pulse waves of frequencies fa and fb and amplified by the waveform shaping circuit 5, respectively. Each of these pulse signals is subtracted by an arithmetic circuit 6, and a signal having a fa-fbO difference frequency is output. This signal is used by the display drive circuit 7 as a display signal for the difference frequency, that is, the difference in the rotational speed between the rotation axes 1 and 2.The digital display 8
is output to. Therefore, the value of the rotational speed difference is displayed on the digital display 8.

However, the conventional rotational speed difference display device has disadvantages in that it requires an arithmetic circuit, a display drive circuit, a digital display, etc., making the circuit complicated and increasing the cost.

The present invention was devised in order to eliminate such drawbacks of the conventional technology, and its purpose is to provide a rotation system that can display the difference in rotational speed between two rotating bodies using a simple structure. An object of the present invention is to provide a numerical difference display device.

In order to achieve such an object, the present invention has the following features: @
One of these coils is made rotatable and a permanent magnet is magnetically coupled to the second coil. Using a meter equipped with a pointer, a current corresponding to the rotational speed of the first rotating body is applied to the first coil. A current corresponding to the rotational speed of the second rotating body is caused to flow through the second coil, and a current O! flows through both coils. I! The system is designed to wave the guideline accordingly.

Hereinafter, the present invention will be explained in detail using Examples.

Figure g2 is a configuration diagram of an embodiment of the rotation speed difference display device according to the present invention. In the figure, the same parts as in FIG. 1 are designated by the same reference numerals. The rotation of the rotary shaft 1 is detected by a sensor 3, and a rotation signal with a frequency fa proportional to the rotation speed Nm is output. This signal is shaped into a rectangular wave pulse by the waveform shaping circuit 10, amplified, and input to the meter drive circuit 11. The rotation of the rotary shaft 2 is detected by a sensor 4, and a rotation signal having a frequency fb proportional to the number of rotations NbK is output. This signal is shaped into a rectangular wave pulse by a waveform shaping circuit 12 and amplified by a meter drive circuit 13.
is input. The meter drive circuits 11 and 13 each generate and output a rectangular wave pulse having a nine-time width in proportion to the frequency of the input signal.

Therefore, the meter drive circuits 11.13 output drive electric currents fiIa and Ib having values proportional to the frequency f''*fb, that is, the rotational speeds Na and Nb, respectively.

On the other hand, 14 is a first coil through which drive current Ia flows;
16 is a cylindrical permanent magnet with a shaft 17 fixed to the center and rotatably supported; 18 is a pointer fixed to the shaft 1T; 19 is the deflection angle of the pointer 18. This is a scale plate to indicate the The permanent magnet 16 is magnetized with eight poles KN at symmetrical positions 180' apart from the periphery. Further, 20 is a zero return coil through which electricity iIo regulated by a resistor 22 flows from a DC power source 21.

A meter is constructed from each of the above parts.

Here, the permanent magnet 16 is always at a constant zero position because it is attracted by the magnetic field generated by the current flowing through the zero return coil A/20. At this time, the pointer 1B points to the zero scale at the center of the scale plate 19. Further, the coils 14 and 15 are installed at appropriate positions so as to be magnetically coupled to the permanent magnet 16, and when a driving current Ia flows through the coil 14, the permanent magnet 16 is moved by an angle proportional to the current value, for example, a clock. When the drive current Ib flows through the coil 15, the permanent magnet 16 rotates counterclockwise, for example, against the zero return force of the coil A-20 by an angle proportional to the current value. It is designed to rotate against the

Therefore, if the rotational speeds of the rotating shafts 1 and 2 are the same, the drive currents Ia and IbO values will be equal, and the coils 14 and 15
The rotational force of the permanent magnet 16 due to this is canceled out, and the pointer 18 points to the zero scale. However, if a difference occurs between the rotational speeds of the rotating shafts 1 and 2, the drive voltage pT'.

There is a difference between the values of Ib and Ib, and the permanent magnet 16 moves in a predetermined direction (I
When s>Ib, it rotates clockwise; when Ia<Ib, it rotates counterclockwise), and the pointer 18 swings by a swing angle θ.

Here, if the number of turns of the coils 14 and 15 is the same n, and the number of turns of the zero return coil 20 is set to no, then the following relational expression is obtained.2°=K(Na-Nb) However, K is a constant.

Therefore, if the scale on the dial 19 is formed according to the difference in rotational speed, it is possible to measure the difference in the rotational speed of the rotating shafts 1 and 2 and which rotating shaft has the highest 0 rotational speed from the instructions of the pointer 18. It can be luxurious.

FIG. 3 is a graph showing the relationship between the rotation speed difference (Na-Nb) and the deflection angle θ of the pointer. Figure 4 shows zero return coil 2
Magnetic field and coil acting on a permanent magnet due to 0 14.15
FIG. 2 is a vector diagram of a magnetic field acting on a permanent magnet.

Incidentally, in the above embodiment, the zero position setting of the permanent magnet can also be performed by a spiral spring using a zero return coil. Further, in the embodiment, the coil is fixed and the permanent magnet is rotated, but it is also possible to fix the permanent magnet and rotate the coil.

At this time, the pointer is fixed to the coil.

As described above, according to the rotation speed difference display device according to the present invention,
With a simple configuration, it is possible to display the difference in the rotation speed of two rotating bodies and whether the rotation speed of the rotating body that is out of alignment is hotter, and has excellent effects such as being applicable to low-cost slip needles. There is.

[Brief explanation of the drawing]

The tsI diagram is a block configuration diagram of a conventional rotation speed difference display device,
FIG. 2 is a configuration diagram of an embodiment of the rotation speed difference display device according to the present invention, and FIG. 3 is a graph showing the relationship between the rotation speed difference and the angle of view.
FIG. 4 is a magnetic field O vector diagram acting on a permanent magnet. 1.2...rotation axis, 3,4...life sensor, 10.
12... Waveform shaping circuit, 11.12... Meter drive circuit, 14.15... Coil, 16...
・Permanent magnet, 17...Axis, 18.Working...Pointer, 19
...Scale plate, 20 books, fist, zero return coil. Patent applicant Jieco - Kinsha Co., Ltd.

Claims (1)

[Claims] A first drive circuit that outputs a required current according to the rotation speed of the first rotating body, a second drive circuit that outputs a current according to the rotation speed of the 1s2 rotating body, and an output current of the aiEt drive circuit. It consists of a first coil that flows an output current, a second coil that flows an output current of a second drive circuit, and a permanent magnet that is magnetically coupled to these coils, and one of these coils and the permanent magnet is rotatably supported. A rotation speed difference display device comprising: a meter having a needle and a pointer, the pointer swinging at an angle corresponding to a difference in current flowing through the first coil and the JIE2 coil.