JPS6116597B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrial robot, in which the pump is unloaded when the oil temperature in the tank is below a predetermined value, and the hydraulic pump is turned on when the oil temperature reaches the predetermined value. An object of the present invention is to provide an industrial robot having a hydraulic system that is stopped and supplies pressure oil to a load.

FIGS. 1 and 2 show block system diagrams during teaching and playback, respectively, of an example of a general playback type industrial robot. First, when teaching, in FIG. 1, the teach/reproduction switch (not shown) provided on the operation panel 2 of the control device 1 is set to the "teach" side, and the start switch provided on the operation panel 2 is set to the "teach" side. When (described later) is pressed, the state becomes available for teaching. Therefore, when the micro switch 4 for starting teaching provided on the manipulator 3 is closed, the command circuit of the control device 1 is
A write command signal is sent from the storage control circuit 6 to the storage device 7 via the storage control circuit 6, and the storage device 7 performs a storage operation.

Here, when the operator moves the movable part 8 of the manipulator 3 according to the desired operation, the displacement of the movable part 8 is converted into an analog signal by the position detector 9 provided on the movable part 8, and the displacement of the movable part 8 is converted into an analog signal. The signal is supplied to the A/D conversion circuit 10, where it is converted into a digital signal in response to the sampling command signal taken out from the command circuit 5, and is stored in the storage device 7.

Next, during the reproducing operation, as shown in FIG. 2, the teaching/reproducing selector switch provided on the operation panel 2 of the control device 1 is set to the "reproducing" side, and the start switch is pressed to enable reproducing. On the other hand, 11 is a limit switch that detects a workpiece (not shown) conveyed by a conveyor (not shown), and this limit switch 11 cooperates with the micro switch 4 and is in a state that can be stored in the command circuit 5 during "teaching". It outputs a signal indicating that there is, and outputs a start signal for starting the movable part 8 to the command circuit 5 during "regeneration". Therefore, once the limit switch 11 that detects the position of the workpiece is closed, a read command signal is supplied from the storage control circuit 6 to the storage device 7 via the command circuit 5, and the storage device 7 starts reading the stored data. However, the stored data is supplied to the D/A conversion circuit 12 and converted into an analog signal (position command signal) Si. At the same time, pressurized oil already pressurized to a predetermined pressure is supplied from the hydraulic pressure generator 13 to the electro-hydraulic servo valve 14 of the manipulator 3.

On the other hand, the position of the movable part 8 is constantly detected by a position detector 9, and the position feedback signal Sf of the movable part 8 is supplied from the detector 9 to the comparison circuit 15. Comparison circuit 15
, the position feedback signal Sf and the position command signal Si are compared, and their deviation ΔS is amplified by the operational amplifier 16 and supplied to the electro-hydraulic servo valve 14 to control the output flow rate of the valve 14. This results in
The actuator 17 is displaced until the deviation ΔS becomes zero, and the movable part 8 reproduces the taught motion while operating as a servo.

In a playback type industrial robot configured in this way, if the temperature of the oil supplied to the manipulator 3 during regeneration is low and does not reach a predetermined value, the viscous resistance of the oil will be large, and the accuracy of the movement of the moving parts will deteriorate. Alternatively, undesirable phenomena such as unstable operation may occur. For this reason, it is generally desirable and required to raise the temperature of the oil to a certain set value before performing regeneration.

However, in conventional playback type industrial robots, while the operator is teaching by moving the movable part 8 of the manipulator 3, even if the worker tries to rotate the pump to raise the temperature of the oil, the pump will not rotate. The drive is disabled to prevent danger. In other words, the pump can only be driven either before teaching or after teaching and with regeneration. If the hydraulic pump is to be driven only in the state where regeneration is possible, the signal for starting the regeneration operation must be temporarily interrupted by, for example, disconnecting the connector of the limit switch 11 of the conveyor, which is cumbersome to operate. There were flaws. In the former case, the pump is stopped during teaching, resulting in a drop in temperature, and both the former and the latter require a mechanism to independently operate the pump drive and manipulator operation, and are costly. However, there were disadvantages such as a high level of energy consumption, which was not desirable from a safety standpoint.

The present invention eliminates the above drawbacks, and the third
An example thereof will be described with reference to FIG. Components that are the same as those in FIGS. 1 and 2 are given the same reference numerals, and their explanations will be omitted.

Figure 3 shows a block system diagram when the industrial robot according to the present invention is applied to a playback type industrial robot. , the dashed-dotted line indicates the flow of electrical signals during "reproduction". Furthermore, FIG. 4 shows a specific circuit diagram of the command circuit 5.

In FIG. 3, a start switch 18 and a main power switch 19 are connected to the command circuit 5 to put the industrial robot into a memorizable state or a reproducible state, and the start switch 18 and main power switch 19 are connected to the operation panel 2. It is set in. on the other hand,
The hydraulic pressure generator 13 is configured as follows.
20 is a tank in which oil is stored, 21 is a pump, one end of which opens into the oil in tank 20, and the other end connected to the P port of a 3-port, 2-position spring-back solenoid valve 22 serving as a three-way valve. It is connected. 23 is a motor that drives the pump 21;
An electromagnetic switch 24 is provided in the middle of the power transmission line leading from the motor 23 to the power source, and the electromagnetic switch 24 supplies and stops power to the motor 23. The electromagnetic switch 24 is connected to the command circuit 5, and is turned on and off by a signal from the command circuit 5. Said solenoid valve 2
The T port of No. 2 is opened to the tank 20, and the A port of No. 2 is opened to the P of the electro-hydraulic servo valve 14.
It is connected to a port (not shown). The T port of the electro-hydraulic servo valve 14 opens directly into the tank 20. By the way, the electromagnetic valve 22 is at P when the solenoid 22' is not operating.
Port and T port are communicated and solenoid 2
2' is connected to the command circuit 5, and releases pressure oil to the tank 20 according to a signal from the command circuit 5,
It is controlled to supply to an electro-hydraulic servo valve 14. A temperature detection switch 25 detects the temperature of the oil in the tank 20, and is connected to the command circuit 5 to detect the temperature of the oil in the tank 20.

Reference numeral 26 denotes a display lamp provided on the operation panel 2, which notifies the operator that the temperature of the oil is low when the temperature of the oil is lower than a set value based on a signal from the temperature detection switch 25. 27 is a push button switch, which is connected to the command circuit 5 and displays the indicator lamp 2.
6 lights up, that is, when the temperature of the oil in the tank 20 is lower than the set value, the pump 21 is operated in an unloading mode. As the pump 21 performs unloading operation, the temperature of the oil in the tank 20 increases.

In FIG. 4 (command circuit 5), 28 to 38 indicate terminals, 39, 40, and 41 indicate D flip-flops, and 42 indicates a JK flip-flop. In addition, 43 to 48 indicate the logical product of two inputs,
49 and 50 represent logical sums, and 51 to 58 represent inverters. Terminal 28 is connected to inverter 51 and to one input of AND 43. The output of inverter 51 is connected to one input of AND 44 and to the T input of D flip-flop 39. terminal 3
0 is connected to the D input and reset input of D flip-flop 39, the reset inputs of D flip-flops 40 and 41, and the reset input of JK flip-flop 42. Q of D flip-flop 39
The output is connected to the other input of the AND 44 , and the output of the AND 44 is connected to the other input of the AND 43 and to the input of the inverter 52 . The output of AND 43 is terminal 3
5. The output of the inverter 52 is connected to one input of the AND 45, one input of the AND 46, the input of the inverter 56, and one input of the OR 49, respectively. Terminal 29 is logical product 4
The output of the AND 45 is connected to the input of the inverter 53,
The output of inverter 53 is connected to terminal 36. Terminal 31 is connected to the input of inverter 55, and the output of inverter 55 is connected to the D input of D flip-flop 40. Terminal 32 is connected to each T input of D flip-flops 40, 41 and JK flip-flop 42. The Q output of D flip-flop 40 is connected to the D input of D flip-flop 41, and the Q output of D flip-flop 40 is connected to one input of AND 47. The Q output of the D flip-flop 41 is connected to the other input of the AND 47,
The output of the AND 47 is connected to the other input of the AND 46, and the output of the AND 46 is connected to the inverter 5.
The output of the inverter 54 is connected to the terminal 37. The terminal 33 is connected to the other input of the OR 49, the output of the inverter 56 is connected to one input of the OR 50, and the output of the OR 49 is connected to the other input of the OR 50. and is connected to one input of AND 48. Terminal 34 is AND 48
The output of AND 48 is connected to the J input of JK flip-flop 42. The output of the logical sum 50 is connected to the input of the inverter 57, and the output of the inverter 57 is
It is connected to the K input of JK flip-flop 42. The Q output of JK flip-flop 42 is connected to the input of inverter 58, and the output of inverter 58 is connected to terminal 38.

A clock pulse is input to the terminal 32 at the same time as the main power switch 19 (FIG. 3) is pressed, and similarly, a low level single pulse is input to the terminal 30 at the same time as the main power switch 19 is pressed. A signal from the temperature detection switch 25 (FIG. 3) is input to the terminal 28, and when the temperature of the oil is below a set value, the signal from the temperature detection switch 25 is at a low level. A single low-level pulse that is output when the main power switch 19 is turned on is input to the terminal 34. When the start switch 18 (Fig. 3) is pressed, a low-level single pulse is input to the terminal 31, and when a low-level single pulse is input to the terminal 31, a high-level single pulse is output from the terminal 37. By outputting the high-level single pulse, the teaching or reproducing state is enabled. A signal for controlling the electromagnetic switch 24 (FIG. 3) is output from the terminal 38, and the electromagnetic switch 24 is closed only while the signal from the terminal 38 is at a low level, and the electromagnetic switch 24 is closed only when the signal from the terminal 38 is at a low level.
supply to. When the signal is output from the terminal 37, the terminal 33 becomes high level, and the terminal 34 becomes the high level.
When a signal is received at the terminal 38, a signal is received which causes the signal at the terminal 38 to be at a low level. A signal is output from the terminal 37 to the terminal 29, and a signal that becomes low level when the microswitch 4 (FIG. 3) is closed is also input. A signal is output from the terminal 36 that becomes low level when the signal input to the terminal 29 becomes low level and operates the solenoid valve 22 (FIG. 3). A high level signal is output from the terminal 35 when the temperature of the oil is below a set value, and the signal lights up the indicator lamp 26 (FIG. 3).

The present embodiment is configured as described above, and its operation will be explained next.

When the operator turns on the main power switch 19, a voltage of 100V is applied to the control device 1. At this time, if the temperature of the oil in the tank 20 is below the set value, the temperature detection switch 25 outputs a signal to the command circuit 5, and the terminal 28 of the command circuit 5 receives a low level signal as described above. Supplied. This signal is converted to a high level signal by the inverter 51, and is supplied to the T input of the D flip-flop 39 and connected to one input of the AND 44. Since the T input and the reset input of the D flip-flop 39 are each supplied with a low level single pulse as described above, a high level signal is supplied from the Q output to the other input of the AND 44, and the AND 44 outputs a low level signal,
This signal is applied to the other input of AND 43. Since the low level signal from the terminal 28 is supplied to one input of the AND 43, a high level signal is output from the AND 43 and the signal is sent to the terminal 35.
supplied to When a high level signal is supplied to the terminal 35, the indicator lamp 26 lights up, as described above, to notify the operator that the temperature of the oil in the tank 20 is below the set value.

Therefore, the push button switch 27 is turned on to raise the temperature of the oil in the tank 20. However, at this time, it is assumed that the command circuit 5 is in the "teaching" state. When the push-button switch 27 is turned on, a low-level single pulse enters the terminal 34, and this single pulse is supplied to the other input of the AND gate 48. Then, unless the start switch 18 is pressed, a single low-level pulse will not be generated.
No signal indicating the teaching or playable state is output from the terminal 37, and a low level signal is input to the terminal 33. This low level signal is supplied to the other input of the logical OR 49. logical sum 49
Since one input of the inverter 52 is supplied with a high level signal, the other input of the OR 50 is supplied with a low level signal. As a result, a high level signal is supplied to the J input of the JK flip-flop 42, and a low level signal is supplied to the K input. Since a clock pulse is always input to the reset input of the JK flip-flop 42, a low level signal is output to the terminal 38. Then, as described above, this signal operates the electromagnetic switch 24 and sends electric power to the motor 23. The motor 23 drives the pump 21 to suck and pressurize the oil in the tank 20.
Also, at this time, even if a single low-level pulse is input to the terminal 31 by pressing the start switch 18, the signal input to the terminal 28 becomes high level due to the D flip-flops 40, 41 and the AND 47. Due to the action of the AND 44 and the inverter 52, the signal output from the terminal 37 does not become high level, and even when the microswitch 4 is closed, the signal input to the terminal 29 does not become low level. Therefore, the signal output to the terminal 36 due to the action of the AND 45 and the inverter 53 does not become low level. As a result, the solenoid valve 22 does not operate,
The oil is not supplied to the electro-hydraulic servo valve 14 but is relieved to the tank, so that the manipulator 3 will not malfunction. Then, as the unloading operation of the pump 21 continues, the temperature of the oil increases, and when the temperature of the oil reaches a set value, the signal input to the terminal 28 becomes high level. As a result, the signal output to the terminal 35 becomes low level, and the indicator lamp 26 turns off. Also, due to the action of the inverter 51, the AND 44, and the inverter 52, the inverter 5
Since the output signal of 2 is low level, the logical sum 4
9, inverter 56, logical product 48, logical sum 50,
Due to the operation of the inverter 57, JK flip-flop 42, and inverter 58, the signal output to the terminal 38 becomes high level, thereby opening the electromagnetic switch 24 and stopping the motor 23 and pump 21. These operations are performed only immediately after the main power switch 19 is turned on.

Next, when the start switch 18 is turned on during regeneration, a signal is supplied to the solenoid valve 22 by the operation of the command circuit 5 to open the port leading to the load and close the oil drain port. Hydraulic oil is supplied to the manipulator 3 by actuation of the solenoid valve 22 . Here, in the same way as explained in FIG. The position feedback signal is compared and the deviation is supplied to the electro-hydraulic servo valve 14 of the manipulator 3. The electro-hydraulic servo valve 14 controls the flow rate of the oil supplied via the already opened solenoid valve 22 according to the deviation, and
reproduces the taught motion through servo operation by displacement of the actuator 17. During this regeneration, the temperature of the oil is always in a pressurized state, so the temperature of the oil does not fall below a set value.

At this time, since the regeneration operation is performed while the temperature of the hydraulic oil has risen to a predetermined value, the regeneration operation can be performed immediately and accurately. Further, in this case, unlike the conventional example, a heater is not used to raise the temperature of the hydraulic oil, so it can be constructed at low cost and is also preferable from the viewpoint of safety.

As mentioned above, according to the industrial robot of the present invention, the pump can be operated independently even during teaching, so stable and accurate operation can be expected from the beginning during regeneration. Gain,
Moreover, when driving the pump, if it is detected that the oil in the tank has fallen below a predetermined temperature and the motor is activated accordingly, the pump will be in unload operation, and the oil in the tank will be activated. The motor will automatically stop rotating when the temperature reaches the set temperature, so if you drive the motor during teaching to raise the temperature of the oil, you can immediately start the regeneration operation when teaching is finished. In addition, if the regeneration operation is performed when the temperature of the oil is low, an abnormal signal will be input to the command circuit and the command circuit will malfunction, but in the present invention, the temperature of the oil is always low. This type of malfunction will not occur because the temperature is rising, and even if the start switch is pressed during unloading operation, it will not malfunction, so it is safe. Furthermore, the temperature of the oil can be raised using a heater, etc. It has features such as being able to be constructed at a lower cost and being safer than the conventional example.

[Brief explanation of the drawing]

Figures 1 and 2 are block system diagrams during teaching and playback, respectively, of an example of a general playback type industrial robot, and Figure 3 is a block system diagram when the industrial robot according to the present invention is a playback type industrial robot. FIG. 4 is a specific circuit diagram of the command circuit 5. DESCRIPTION OF SYMBOLS 1...Control device, 3...Manipulator, 4...Micro switch, 5...Command circuit, 8...Movable part, 13...
Hydraulic generator, 14...Electro-hydraulic servo valve, 17
...actuator, 18...start switch, 1
9... Main power switch, 20... Tank, 21... Pump, 22... Solenoid valve, 23... Motor, 24... Solenoid switch, 25... Temperature detection switch, 26... Display lamp, 27... Push button switch.

Claims (1)

[Claims] 1. A pump for raising the oil liquid to a predetermined pressure, a motor for rotating the pump, an electromagnetic switch for controlling the rotation of the motor, and a pump provided between the pump and the actuator. A three-way switching valve selectively supplies oil to a tank and an actuator, an operating switch for operating the electromagnetic switch when the pump is operated in an unloading operation, and detecting the temperature of the oil in the tank. an indicator light that lights up when the temperature of the oil fluid is below a set value, and output signals from the operating switch and temperature switch are input to operate the electromagnetic switch, three-way switching valve, and indicator light, respectively. The command circuit is configured to turn on the indicator light by the output of the temperature switch inputted to the command circuit when the temperature of the oil liquid is below a set value, and to turn on the indicator light by operating the operation switch. Then, the electromagnetic switch and the three-way switching valve are operated via the command circuit to cause the pump to perform an unloading operation, while the three-way switching valve is inactivated during the unloading operation, and the temperature of the oil fluid is maintained at the set value. The industrial robot is characterized in that, when the above temperature switch occurs, the electromagnetic switch is deactivated via the command circuit in response to a signal from the temperature switch, and the pump is stopped.