JP2741955B2 - Servo motor controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo motor control device for controlling an electric motor such as a servo motor, and more particularly to a servo motor control device capable of reducing the number of wires wired between a servo motor and a servo controller.

[0002]

2. Description of the Related Art Conventionally, servo motor control devices used for NC machine tools and the like require precision and safety.
The servo motor includes a position detector that accurately detects the position of a movable portion, and a temperature detector that monitors the temperature of the motor so as not to overheat and detects an overload, for example, a thermal.

FIGS. 8 to 10 show a conventional servo motor controller. FIG. 8 is a circuit diagram showing a main part of the conventional servo motor controller, and FIG. 9 is a servo motor to which the circuit shown in FIG. 8 is applied. FIG. 10 is a schematic cross-sectional view of the servomotor shown in FIG. 9 showing an example of the actual wiring of the control device. In FIG. 9, the servo motor 10 is connected to a power line 16 b-16 from the power circuit 14 of the servo controller 12.
U, V, via a, 18b-18a, 20b-20a
The W-phase power is supplied, and the rotating shaft 22 is driven to rotate.
The rotating shaft 22 is coupled to an input shaft 26 of the position detector 24 by a coupling 28 as shown in FIG. The position detector 24 detects the rotational position of the rotating shaft 22 which is a movable part by a position detecting circuit 29 shown in FIG. 8, and transmits this position signal (position data) to the servo controller 12 via signal lines 30a-30b. This is fed back to the control circuit 32. The position signal is transmitted by serial data transmission through one signal line 30a-30b. This is because parallel data transmission requires signal lines corresponding to the number of output bits, but serial data transmission requires a position detector 2.
This is because it is not necessary to increase the number of signal lines even if the resolution of 4 is improved. However, in the case of serial data transmission, in order to synchronize the serial data with the signal of the data processing circuit (the position detection interface 33 shown in FIG. 8) of the control circuit 32, the control circuit 32 transmits the signal via signal lines 34b-34a. The clock signal is transmitted to the position detector 24. Also,
The DC voltage for driving the position detector 24 is supplied to the power supply line 36b.
Power supply unit 4 shown in FIG.
0 is applied. The power supply lines 38b-38
a is a reference potential, and 36b-36a are power supply potentials.

On the other hand, as shown in FIG. 9 and FIG. 10, a thermal 44 is embedded in a winding 42 of the servomotor 10, and a control circuit of the servo controller 12 is connected via signal lines 46a-46b and 48a-48b. 32. As shown in FIG. 8, the control circuit 32 is provided with an overload detection circuit 50. When the thermal 44 detects abnormal heating of the winding 42, the control circuit 32 does not send power to the servomotor 10. To control the power circuit 14. The electric wires 30a-30b, 34 of the position detector 24
b-34a, 36b-36a, 38b-38a are bundled with a cable 52, and the electric wire 16b-1 of the servomotor 10 is
6a, 18b-18a, 20b-20a and electric wires 46a-46b, 48a-48b of the thermal 44 are bundled with a cable 54.

[0005]

As described above, in the conventional servo motor control device, the servo controller 12
Power lines 16b-16a connecting the servo motor 10 and the
18b-18a, 20b-20a, signal lines 30a-30 connecting the servo controller 12 and the position detector 24
b, 34b-34a and power supply lines 36b-36a,
38b-38a, servo controller 12 and thermal 4
A large number of electric wires are used, such as signal lines 46a-46b, 48a-48b connecting the four. For this reason,
The conventional servomotor control device has a problem in that the cost is increased due to the large number of wires and the reliability is reduced.

Therefore, the invention according to claim 1 has been made in order to solve the above-mentioned problems of the prior art.
It is an object of the present invention to provide a servomotor control device capable of reducing the number of wires connected between a servomotor and a servo controller by superimposing a position signal detected by a position detector on a power supply line.

[0007] The invention according to claim 2 is characterized in that the position signal and
Superimposing the composite signal with the thermal signal on the power supply line
Reduces wires for transmitting position and thermal signals
To provide a servo motor control device capable of
You.

That is, in the present invention, the number of electric wires is made possible.
The purpose is to maintain reliability while suppressing as much as possible.

[0009]

According to the first aspect of the present invention,
To achieve the above object, a position detector for detecting a position of a movable portion of a servomotor, a power supply line for supplying a DC voltage for driving the position detector, and a position signal detected by the position detector A servo controller that controls the servo motor while performing feedback, a servo controller that is provided on the servo motor side and superimposes the position signal on the power supply line .
Superposition means, and a clock which is a transmission synchronization signal of the position signal.
And a second superimposing means for superimposing a power signal on the power supply line .

According to a second aspect of the present invention, there is provided a position detecting section for detecting a position of a movable section of a servomotor , and a driving DC voltage supplied to the position detector.
A power supply line to be supplied, a temperature detecting means for monitoring the temperature of the servomotor to detect an overload, and a position signal detected by the position detector and a thermal signal detected by the temperature detecting means being fed back while feeding back the thermal signal. in the servo motor controller comprising a servo controller for controlling the servo motor, wherein the provided to the servomotor side, a synthesizing means for synthesizing the position signal and the thermal signal to create a combined signal from the combining means Output
The first overlap which superimposes the synthesized signal on the power line of the position detector
Tatami means and a clock which is a transmission synchronization signal of the position signal
Yes second superimposing means for superimposing a signal on the power line, the
Characterized in that it.

As described above, according to the present invention, the position signal and the position
Superimpose composite signal of signal and thermal signal on power line
At the same time, the clock signal that is the transmission synchronization signal is also
Is superimposed on the

[0012]

According to the present invention, the position signal detected by the position detector is superimposed on the power supply line, and the clock signal is also superimposed on the power supply line.
By doing so, the number of electric wires can be reduced.

Further, in the invention according to claim 2, the position
Signal and thermal signal are superimposed on the power line.
Also, by superimposing the clock signal on the power line,
The number of electric wires can be reduced.

Note that the position signal and the thermal signal are
After being synthesized by the stage, it is superimposed on the power supply line.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an embodiment of a servo motor control device according to the first aspect of the present invention. FIG. 1 is a circuit diagram showing a main part thereof, and FIG. 2 includes the circuit of FIG. FIG. 3 is a schematic circuit diagram showing an actual wiring example of a servomotor control device to which the circuit shown in FIG. 1 is applied. Note that, in the present embodiment, for the same configuration as the above-described example,
The same reference numerals are given and the detailed description is omitted.

Referring to FIG. 2 and FIG.
The position detection circuit 29 of the power supply unit 40 of the control circuit 32 from the power supply line 36b-136b-136a-36a,
Driving DC voltages are supplied via 38b-138b-138a-38a. From the position detection circuit 29, a position signal, which is serial data of a high-frequency pulse, is transmitted to a signal line 30a.
Is output to the input / output circuit 60 via Input / output circuit 60
Is, as shown in FIG.
4, 66, a resistor 68, 70, a capacitor 72, etc., and a superposition circuit 74 of a position signal is provided.
a-136b. Power supply lines 136a-136
b is connected to the input / output circuit 76 of the control circuit 32. As shown in FIG. 1, the input / output circuit 76 is provided with a position signal extraction circuit 86 including a capacitor 78, resistors 80 and 82, a buffer 84, and the like. Line 136
The position signal is extracted by removing the DC voltage component from a-136b. The extracted position signal is output to the position detection interface 33 via the signal line 30b.

On the other hand, from the position detection interface 33, a clock signal, which is a synchronization signal
4b. As shown in FIG. 1, the input / output circuit 76 includes a clock signal superimposing circuit 100 including a buffer 88, transistors 90 and 92, resistors 94 and 96, a capacitor 98, and the like. The clock signal is supplied to a power supply line 136.
b-136a. Power supply line 136b-136
a is connected to an input / output circuit 60 of the position detector 24. As shown in FIG. 1, the input / output circuit 60 has a clock signal composed of a capacitor 102, resistors 104 and 106, a buffer 108 and the like. Extraction circuit 110 is provided. The DC signal is removed from the power supply lines 136b-136a by the capacitor 102 of the extraction circuit 110 to extract the clock signal. The extracted clock signal is output to the position detection circuit 29 via the signal line 34a.

A low-pass filter 118 composed of coils 112 and 114, a capacitor 116 and the like is provided between the power supply lines 36b and 136b.
A low-pass filter 126 composed of coils 120 and 122, a capacitor 124 and the like is inserted between them.
High frequency components of the clock signal and the position signal are cut. As a result, a stable DC voltage is applied to the position detection circuit 29.

As described above, in the present embodiment, the position signal detected by the position detector 24 is transmitted to the power line 36b.
By superimposing -136b-136a-36a,
The number of wires for transmitting position signals can be reduced, and the number of wires wired between the servo motor and the servo controller can be reduced.
Therefore, costs can be reduced by reducing the number of wires, wiring errors can be reduced, and troubles due to broken wires can be reduced, and reliability can be improved.

FIG. 4 is a circuit diagram showing another embodiment of the servomotor control device . In the present embodiment, the same components as those in the above-described example are denoted by the same reference numerals, and a specific description thereof will be omitted. In the figure, the position detector 24 is
There is provided a synthesizing circuit 150 to which the position signal and the thermal signal are inputted via the signal lines 30a, 46a, 48a. The combining circuit 150 combines the position signal and the thermal signal to create a combined signal. This data is stored in one signal line 13
The signal is transmitted to the control circuit 32 via the lines 0a-130b. The control circuit 32 is provided with a separation circuit 152, and the code data is decoded by the separation circuit 152. The position signal and the thermal signal separated by the decoding are output to the position detection interface 33 and the overload detection circuit 50 via the signal lines 30b, 46b, and 48b, respectively.

As described above, in this embodiment, the position signal and the thermal signal are connected to one signal line 130a-130b.
Therefore, the number of electric wires can be reduced.

FIGS. 5 to 7 are circuit diagrams showing one embodiment of the servo motor control device according to the second aspect of the present invention. FIG. 5 is a circuit diagram showing a main part thereof, and FIG. FIG. 7 is a schematic configuration diagram showing an actual wiring example of a servo motor control device to which the circuit shown is applied, and FIG. 7 is a schematic sectional view of the servo motor shown in FIG. In the present embodiment, the same components as those in the above-described example are denoted by the same reference numerals, and a specific description thereof will be omitted.

5 to 7, a composite signal from the composite circuit 150 is supplied to the input / output circuit 60 via a signal line 130a.
Is output to In the input / output circuit 60, the superposition circuit 7
4, the combined signal is supplied to the power supply lines 236a-236.
b. The composite signal superimposed on the power supply lines 236a-236b is supplied to the input / output circuit 76 of the control circuit 32.
The combined signal is extracted by the extraction circuit 86 in the input / output circuit 76 . Then, the extracted synthesized signal is separated into a position signal and a thermal signal by the separation circuit 152, and the position detection interface 3
3. Output to the overload detection circuit 50.

As described above, in this embodiment, since the position signal and the thermal signal can be transmitted while being superimposed on the power supply lines 236a-236b, the number of electric wires in the actual wiring can be reduced.

In this embodiment, the power supply line 23
6a-236b and 238a-238b are connected to the power line 16b.
-16a, 18b-18a, and 20b-20a are housed in the cable 54.
-236b, 238a-238b, the position signal and the thermal signal superimposed on the power lines 16b-16a, 18b-
When receiving noise from 18a, 20b-20a,
In the cable 54, the power supply lines 236a-236b, 23
8a-238b is electromagnetically shielded.

[0027]

As described above, according to the first aspect of the present invention, the position signal is transmitted by superimposing the position signal detected by the position detector on the power supply line. The number of wires can be reduced, and the number of wires wired between the servomotor and the servo controller can be reduced. Therefore, the number of electric wires in actual wiring can be reduced, and cost reduction and reliability improvement can be realized.

Further, according to the servo motor controller according to the second aspect of the present invention, the position signal and the thermal signal electric
Since transmission can be performed while being superimposed on the source line, the number of electric wires can be reduced. Therefore, cost reduction and reliability improvement by reducing the number of electric wires can be realized.

In each of the above inventions, the clock signal
Is also superimposed on the power line, further reducing the number of wires
Is possible.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a main part of a servo motor control device according to the first embodiment.

FIG. 2 is a schematic circuit configuration diagram including the circuit of FIG. 1;

FIG. 3 is a schematic configuration diagram showing an example of actual wiring of a servo motor control device to which the circuit shown in FIG. 1 is applied;

FIG. 4 is a circuit diagram showing another embodiment of the servomotor control device .

FIG. 5 is a circuit diagram showing a main part of a servo motor control device according to the second embodiment.

6 is a schematic configuration diagram showing an example of actual wiring of a servo motor control device to which the circuit shown in FIG. 5 is applied.

FIG. 7 is a schematic sectional view of the servomotor shown in FIG. 6;

FIG. 8 is a circuit diagram showing a main part of a conventional servo motor control device.

9 is a schematic configuration diagram showing an example of actual wiring of a servo motor control device to which the circuit shown in FIG. 8 is applied.

FIG. 10 is a schematic sectional view of the servomotor shown in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Servo motor 12 Servo controller 24 Position detector 36, 38 Power supply line 44 Thermal 74 Superposition circuit 86 Extraction circuit 150 Synthesis circuit 152 Separation circuit

Claims (2)

(57) [Claims] 1. A position detector for detecting a position of a movable portion of a servomotor, a power supply line for supplying a DC voltage for driving the position detector, and a position signal detected by the position detector being fed back. A servo controller that controls the servo motor; a first superimposing unit provided on the servo motor side for superimposing the position signal on the power supply line; and a transmission synchronization signal of the position signal. A certain clock signal
And a second superimposing means for superimposing on a power supply line . 2. A position detector for detecting a position of a movable portion of a servomotor, a power supply line for supplying a drive DC voltage to the position detector, and monitoring the temperature of the servomotor to detect an overload. A servo motor control device comprising: a temperature detection unit; and a servo controller that controls the servo motor while feeding back a position signal detected by the position detector and a thermal signal detected by the temperature detection unit. A combining unit that combines the position signal and the thermal signal to create a combined signal; and a first superimposing unit that superimposes the combined signal output from the combining unit on a power supply line of the position detector. A clock signal that is a transmission synchronization signal of the position signal,
Servo motor controller, wherein the second superimposing means for superimposing the power line, to have a.