JPH03230209A - Electronic control lever device - Google Patents

Abstract

PURPOSE:To prevent a machine from operating in an unexpected direction by outputting a control signal corresponding to the time when a lever is neutral when electric trouble occurs during operation by lever operation. CONSTITUTION:When the lever 1 is operated in the positive direction, an opera tion signal for the positive lever direction is outputted from operation direction detection switch 36a and 36b and a signal corresponding to the lever operation angle is outputted from a potentiometer 35y. If an electric conductor is broken in this state, the same signal as that when the lever 1 is placed in negative-directional full-stroke operation is outputted by the potentiometer 35y. The lever positive-directional operation signal is outputted from the switches 36a and 36b at this time, so those two signals have a contradiction. In such a case, a control means 5 outputs a signal corresponding to the time of the lever 1 is at the neutral position to return a control valve 6 to the neutral position, and an actuator is stopped immediately. Consequently, even if electric trouble occurs in the middle of boom elevation, the boom is never moved down abruptly.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an electric control for controlling the operating direction, operating speed, or force of a machine such as a hydraulic excavator or crane by an operator operating a lever. This invention relates to a lever device.

[Prior art]

Conventionally, when a lever is operated, a potentiometer outputs an electrical signal according to the lever operating angle, and that electrical signal switches the control valve, controlling the operation of the actuator and the operation of the machine. As a lever device, for example, JP-A-61-1
Those shown in Japanese Utility Model Publication No. 90620 and Japanese Utility Model Application Publication No. 64-3935 are known. In the former case, one potentiometer (rotary type) is attached to one end of the rotating shaft of the lever, and this one potentiometer is used to detect the leftward operating angle and rightward operating angle of the lever. The latter has a potentiometer (direct-acting type) for each direction of lever operation.
are arranged to face each other, and the leftward and rightward operating angles of the lever are detected by a pair of potentiometers.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, in the method of detecting the operating angle in two directions, right and left, using one potentiometer, as in the former method,
Compared to the latter method, which uses independent potentiometers for each operating direction to detect the operating angle, it is possible to reduce the number of installed potentiometers and reduce costs, but electrical wiring for the potentiometers etc. is required during work. If an electrical problem occurs, such as disconnection of the connector, poor contact or disconnection of the connector, there is a risk that the machine will move in an unexpected direction, and to prevent this, it is necessary to provide a separate safety device.

That is, a potentiometer generally has an output that changes proportionally from zero to maximum when operated in one direction. Therefore, when detecting the leftward operating angle and rightward operating angle with one potentiometer, the output of the potentiometer will have a minimum value when the lever is operated to the maximum leftward operating angle, and a minimum value at the neutral position. It is set to be an intermediate value, and the maximum value will be reached when the operation angle is reached to the right. For this reason, for example, when raising or lowering the boom by operating the lever in the left and right directions on a hydraulic excavator, the lever is operated in the right direction, the potentiometer outputs a signal greater than the intermediate value, and that signal is used to control the control valve. If an electrical problem like the one described above occurs when the potentiometer is switched to the boom-raising side and the boom is being raised, the output from the potentiometer becomes zero and the lever is being operated to the left, that is, in the boom-lowering direction. The situation will be the same as in , and the boom will drop suddenly.

On the other hand, if potentiometers are provided opposite each other in each direction of lever operation, as in the latter case, by setting the lever so that it is neutral and the output of each potentiometer is zero, it is possible to Even if an electrical problem occurs and the signal is no longer output from the potentiometer, the lever will be in the same state as when it is in the neutral position, so there is no risk of the boom suddenly descending like in the former case, or if an expensive potentiometer is used in each direction of left and right operation. Since a total of two units are required, there is a problem in that the cost increases.

The purpose of the present invention is to reduce costs by reducing the number of potentiometers installed, and to set the lever to a neutral state when an electrical trouble as described above occurs while operating the lever. To provide an electric control lever device capable of immediately stopping a machine and reliably preventing the machine from operating in an unexpected direction.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a lever supported by a support member so as to be rotatable in positive and negative directions from a neutral position, a neutral return spring mechanism that biases the lever to the neutral position, and a neutral return spring mechanism for urging the lever to the neutral position. An operation direction detection switch, a potentiometer that outputs an electrical signal according to the amount of lever operation, and a signal from the operation direction detection switch and a signal from the potentiometer are input to determine whether or not there is a contradiction between the two signals. When there is no contradiction, the control means outputs a control signal according to the direction and amount of operation of the lever, and when there is a contradiction, the control means outputs a control signal corresponding to when the lever is in the neutral position. There is.

In this configuration, the number of the potentiometers is one,
As a result, the lever outputs an electric signal that gradually decreases in proportion to the amount of operation in the negative direction from neutral and gradually increases in proportion to the amount of operation in the positive direction.

[For production]

In the above configuration, when the lever is operated in the forward direction, the operation direction detection switch outputs a lever operation signal in the forward direction, and the potentiometer outputs a signal corresponding to the lever operation angle. If, for example, the wiring to the power supply side or output side of the potentiometer is disconnected in this state, the output signal from the potentiometer becomes zero, and the same signal as when the lever is fully stroked in the negative direction is output from the potentiometer. However, at this time, since the switch outputs a signal for operating the lever in the forward direction, the signal from this switch and the signal from the potentiometer conflict with each other. In such a case, the control means determines that there is a contradiction between the two signals and outputs a signal corresponding to when the lever is in the neutral position. This signal returns the control valve to its neutral position and immediately stops the actuator. Therefore, even if an electrical problem such as the above-mentioned wire breakage occurs while the boom is being raised, the control valve will not be switched to the boom lowering side, and there will be no risk of the boom suddenly descending.

[Example] In FIG. 1, a lever 1 is rotatable in a front-back direction centered on the X-axis and in a left-right direction centered on the Y-axis via a universal joint 12 on a caning 2 as a support member. is supported by A pair of arms 3x, 3
y is formed of a steel band or the like to have an arcuate cross section, and elongated holes 3Lx and 31Y are provided at the center in the width direction, and each elongated hole 31x,
With lever 1 engaged with 31y, both arms 31x
31y are arranged so as to intersect in a planar cross shape.

Both ends of one arm 3x are supported by shafts 32x and 33x on the X-axis so as to be rotatable in the front and rear directions with respect to the bracket 21, and both ends of the other arm 3y are supported by shafts 32y and 33x on the Y-axis.
3y (see FIG. 2), it is rotatably supported by the bracket 21 in the left-right direction. Bracket 21 is fixed to casing 2. Cams 34x and 34y for detecting operation direction are connected to the respective negative shafts 32x and 32y on the X-axis and Y-axis, respectively, and potentiometers 35x and 35 for detecting the amount of operation (operation angle) are connected to the other shaft 33x33y.
y are each connected. Operation direction detection switches 36c are provided on both front and rear sides of the cam 34x and on both left and right sides of the cam 34y.

36d, 36a, and 36b are arranged, and each of these switches is fixed to the bracket 21.

A disc-shaped actuating member 11 is integrally connected to the base end of the lever 1, and this actuating member 11 rotates together with the lever 1. In the casing 2, bushing rods 4a are provided at predetermined intervals on the left and right and front and rear around the universal joint 12.

4b, 4c, and 4d are arranged, and are supported so as to be slidable in the vertical direction via guide bushes 41a, 41b, 41c, and 41d. Bush rod 4a, 4
At the rear end of the bushing rod 4C14d, the casing 2 is provided with spring chambers 42a, 42b, each spring chamber 42a.

Within 42b, neutral return springs 45a, 45b are provided between the spring receivers engaged with the rear ends of the bushing rods 4a, 4b and the cover 44, and these springs 45a, 45b cause each bushing rod 4a to , 4b are urged in the projecting direction, the tips of the bushing rods 4a, 4b abut against the lower surface of the actuating member 11, and the lever 1 is held at the neutral position. A spring receiver is provided in each spring chamber 42a, 42b to regulate the stroke of the members 43a, 43b.
A stepped portion is provided to restrict the maximum stroke of the lever 1 in the left-right direction, that is, the maximum operating angle.

When the lever 1 is in the neutral position, each operating direction detection switch 36a to 36d is OFF.

When the lever 1 is operated in the left-right direction, the arm 3y rotates in the left-right direction together with the lever 1, and the operating direction detection switch 36a, 3 on either the left or right side shown in FIGS. 2 and 3
6b is actuated to detect the operating direction of the lever 1, and at the same time, the potentiometer 35y is actuated and an electric signal corresponding to the lever operating angle is output. In addition, when lever 1 is operated either forward or backward, arm 3x is integrated with lever 1.
Then, the cam 34x rotates in the front and rear directions, and the operation direction detection switches 36c and 36d on either the front or rear are activated to detect the operation direction of the lever 1, and the potentiometer 35x is activated to generate electricity according to the lever operation angle. A signal is output.

The electric control lever device constructed as described above is connected to the control block shown in FIG. 4.

Although this control block diagram only shows a control system for operating the lever 1 in the left and right directions, a control system for operating the lever 1 in the front and back directions is similarly configured. In FIG. 4, 5 is a controller (control means), 6La and 61b are electromagnetic proportional pressure reducing valves, and 6 is a control valve. controller 5
is equipped with control equipment as shown in FIG.

In FIG. 5, 51a and 51b are chattering preventers, 52 is a differential amplifier, 53 is an inverting amplifier, 54 and 5
5a and 55b are comparators, 56 is a signal selection means, 5
7a and 57b are signal generators, 58a and 58b are output terminals, and the output terminals 58a and 58b are connected to electromagnetic proportional pressure reducing valves 61a and 61b shown in FIG. 4.

Here, assuming that the leftward operation of the lever 1 is negative and the rightward operation is positive, the output voltage V of the potentiometer 35y is
As shown in Figure 6, move the lever 1 to the left at the maximum operating angle (-
The lowest value (0.5V) is when the lever is in the neutral position (200), the intermediate value (2,5V) is when the lever is in the neutral position, and the highest value (0.5V) is when the lever 1 is tilted to the right to the maximum operating angle (20G).
5v). That is, the output voltage V of the potentiometer 35y gradually decreases as the lever 1 is tilted leftward (negative direction) from the neutral position, and gradually increases as the lever 1 is tilted rightward (positive direction).

On the other hand, when the lever 1 is in the neutral position, the operating direction detection switches 36a and 36b are both turned off, and when the lever 1 is pushed to the left, the switch 36a is turned on, and when it is pushed to the right, the switch 36b is turned on. At this time, each switch 36a, 36b is controlled by the chattering preventer 53a, 5'3b.
As shown in FIG. 7, when the lever 1 is operated in the leftward and rightward directions, a constant detection signal (voltage) related to the operating angle is input to the signal selection means 56.

The differential amplifier 52 generates a reference voltage v2 when the lever 1 is neutral.
and the output signal (potential) from the potentiometer 35y is amplified and output, and when the difference is positive, that is, when the lever 1 is operated in the right (positive) direction, a positive signal corresponding to the difference is output. The control signal is input to the signal generator 58b for normal operation. Note that when the difference is negative, that is, when the lever 1 is operated in the left (negative) direction, the difference is inverted to a positive signal by the inverting amplifier 53, and is manually input to the signal generator 58a for negative operation. (See Figure 8). Each of the signal generators 58a, 58
b is composed of an analog switch, relay, or the like. Comparator 54 determines whether the output from differential amplifier 52 is positive or negative, and sends the result to signal selection means 56.

, the controller 55a is such that the output signal (potential) from the potentiometer 35 is equal to or higher than the reference voltage ■1 corresponding to the potential when the lever 1 is operated to the stroke end (-200) in the left (negative) direction. When the output signal is equal to or higher than the reference voltage v4, an actuation enable (ON) signal is output, and when the output signal is less than the reference voltage V, the output is set to zero (OFF). The comparator 55b is connected to a base 1 whose output signal from the potentiometer 35y corresponds to the potential when the lever 1 is operated to the right (positive) stroke end (200).
! determines whether the voltage is higher than or equal to voltage v3, and outputs an operation enable (ON) signal when the output signal is lower than or equal to reference voltage v3;
When the reference voltage v3 is exceeded, the output is set to zero (OFF).

The signal selection means 56 inputs the signals from the switches 36a, 36b (chattering preventers 51a, 51b) and the signals from the comparators 54, 55a, 55b, and determines whether there is any contradiction between the signals. determine whether
When there is no conflict, a signal generator 57a corresponds to the operation of the switches 36a and 36b.

An activation signal is output to 57b.

In the above configuration, when the lever 1 is operated in the right direction, the operation direction detection switch 36b is operated by the above-described action, and the potentiometer 357 is also operated, and these signals are transmitted to the controller shown in FIGS. 4 and 5. 5
is input.

Here, if each electrical system is operating normally, the signal from the switch 36b is input to the signal selection means 56 via the chattering preventer 51b in FIG. 5. On the other hand, the differential amplifier 52 controls the potentiometer 35y.
The difference between the 8-force signal from the 8-force signal and the reference voltage v2 when the lever is in the neutral position is amplified and extracted. At this time, since the lever 1 is operated in the right (positive) direction, the output signal from the differential amplifier 52 is positive and corresponds to the operating angle of the lever 1 in the right direction. Then, a signal corresponding to the lever operation angle is sent to the normal operation signal generator 57b. Further, since the output signal from the differential amplifier 52 is positive, a positive signal is sent from the comparator 54 to the signal selection means 56. Further, since the output signal from the potentiometer 35y is within the reference voltage V3 (the maximum operating angle of the lever in the right direction), the signal selection means 56 is output from the comparator 55b.
An operation (ON) signal is sent to the Also, since the output signal from potentiometer 35y is within the reference voltage (maximum operating angle in the left direction of the lever), comparator 5
An operation (ON) signal is sent to the signal selection means 56 from 5a.

In this case, since there is no contradiction between the signals input to the signal selection means 56, an activation signal is output from the signal selection means 56 to the signal generator 57b on the normal operation side, and the signal generator 57b is activated. Then, a control signal (see FIG. 8) corresponding to the lever operation angle determined by the differential amplifier 52 is output from the signal generator 57b, and the control signal is transmitted via the output terminal 58b to the electromagnetic proportional ratio shown in FIG. It is input to the pressure reducing valve 61b.

As a result, a pilot pressure corresponding to the lever operation angle is output from the electromagnetic proportional pressure reducing valve 61b, and the control valve 6 is switched using the pilot pressure.

As a result, the actuator (not shown) is operated in the forward direction, and operations such as raising the boom are performed normally.

Next, while operating the lever 1 in the right direction, an electrical problem such as a poor connection, disconnection, or disconnection of the connector occurs at the power (+) side connection or the output side connection of the potentiometer 35. In this case, the output from the potentiometer 35 becomes zero. At this time, the lever 1 is being operated rightward, and a rightward operation signal of the lever 1 is input from the switch 36b to the signal generator 56 via the chattering preventer 51b. On the other hand, the differential amplifier 5
2 outputs a negative signal lower than the reference voltage v2. Therefore, the negative signal output from the differential amplifier 52 is inverted to a positive signal by the inverting amplifier 53, and the signal is sent to the negative operation signal generator 57a. However, in this case, since the output signal from the differential amplifier 52 is negative, a negative signal is sent from the comparator 54 to the signal selection means 56.

Also, the output signal from the potentiometer 35y is zero,
Since the reference voltage is below v3, the comparator 55b outputs an operation (ON) signal to the signal selection means 56, or the output signal from the potentiometer 357 is less than the reference voltage v3, so the comparator 55a selects the signal. A disable (OFF) signal is sent to the means 56.

In this case, a contradiction will occur between the signals input to the signal selection means 56. Therefore, the signal selection means 56 outputs an OFF signal to each signal generator 57a, 57b, and the electromagnetic proportional pressure reducing valves 61a, 61b shown in Fig. 4 are output.
Neither operates, and the control valve 6 is returned to the neutral position.

In this way, even if an electrical problem occurs on the power supply side or output side of the potentiometer 35y and the output becomes zero while operating the lever 1 in the right (positive) direction, the controller 5
A negative operation signal is not output from the lever, and a signal corresponding to when the lever is in the neutral position is output. As a result, the control valve 6 is returned to the neutral position, so the actuator is immediately stopped, and the boom is immediately stopped without descending suddenly.

Further, if an electrical trouble as described above occurs on the ground (-) side of the potentiometer 35 during the above operation, the potentiometer 35 outputs a high voltage close to the power supply voltage. Therefore, the differential amplifier 52 outputs a positive signal to the signal generator 57b for positive operation as if the lever 1 had been operated more than a full stroke in the right direction, and the comparator 54 outputs a positive signal to the signal selection means 56. A signal is output from the comparator 55a as well as from the signal selection means 56.
An operation (ON) signal will be output. However, in this case, since the output signal from the potentiometer 35y exceeds the reference voltage v3, the comparator 55b
An inoperable (OFF) signal is output from the signal selection means 56.

In this case as well, there will be a contradiction between the signals input to the signal selection means 56. Therefore, the signal selection means 56 outputs an OFF signal to each signal generator 57a, 57b, and the electromagnetic proportional pressure reducing valves 61a, 61 in FIG.
Neither b is activated, and the control valve 6 is returned to the neutral position.

In this way, even if an electrical problem occurs on the ground (-) side of the potentiometer 35y and the output becomes higher than necessary while the lever 1 is being operated in the right (positive) direction, the controller 5 will send a signal that exceeds the lever operating angle. No operation signal is output. Then, the controller 5 outputs a signal corresponding to when the lever is in the neutral position. As a result, the control valve 6 is returned to the neutral position, the actuator is immediately stopped, and the boom is immediately stopped without any sudden rise.

In addition, if the above electrical trouble occurs when lever 1 is in the neutral position, when it is operated to the left, or when it is operated either forward or backward to operate other actuators. Almost the same control as above is also performed to ensure that the machine does not move in an unexpected direction.

FIG. 9 shows an embodiment in which the above device is provided with reaction force control means. In FIG. 9, 62 is a sensor 63a that detects the operating state of the actuator, such as the load pressure.
, 63b is an electromagnetic proportional pressure reducing valve, 64 is a hydraulic power source, and the pilot pressure output from the secondary side of the electromagnetic proportional pressure reducing valves 63a, 63b is transferred to the spring chamber 42 provided in the casing 2.
a, 42b.

In this embodiment, when lever 1 is operated to the right,
The control valve 6 is switched by the same action as described above, and the actuator (not shown) is operated in the forward direction. At this time, the operating state of the actuator, such as the load pressure, is detected by the sensor 62, and the detection signal is input to the controller 5. The controller 6 outputs an electric signal according to the operating state of the actuator to the electromagnetic proportional pressure reducing valve, in this case 63b. As a result, pilot pressure corresponding to the operating state of the actuator is output from the electromagnetic proportional pressure reducing valve 63b, and the pilot pressure is applied to the spring chamber 4.
2b.

Initially, when the lever 1 is operated in the right direction, the actuating member 11 is rotated in the same direction, and the bushing rod 4b is pushed down by the actuating member 11 against the spring 45b. 42b, the bushing rod 4b is urged in the protruding direction,
A force, ie, an operation reaction force, acts on the actuating member 11 and the lever 1 integrated therewith to push it back to the neutral position. In this case, since a pilot pressure corresponding to the operating state of the actuator is input to the spring chamber 42b, the operation reaction force is controlled according to the operating state of the actuator. Therefore, by sensing changes in the operational reaction force with the operator's hand operating the lever 1, the operating state of the actuator, such as the start of movement, the magnitude of the load pressure, etc., can be easily determined.

Note that when the lever 1 is operated to the left, the operation reaction force is controlled by the same effect as described above, and it is possible to easily know the movement of the actuator in the negative direction.

In the above embodiment, potentiometer 35x.

35y is not limited to a rotary type, but a direct acting type may also be used. Furthermore, in the above embodiment, one lever 1 is used to perform two systems of operation in the front-rear direction and left-right direction, but the device of the present invention performs only one system of operation in either the front-rear or left-right direction. It can also be applied to

Furthermore, in the above embodiment, the boom is raised and lowered by operating the lever 1 in the left and right directions. The device of the present invention is not limited and can be arbitrarily selected, and the device of the present invention can be applied to the operation of the boom, arm, and packet of a hydraulic excavator, the boom of a hydraulic crane, a hoisting rope, and other construction machines.

〔Effect of the invention〕

As described above, the present invention uses one potentiometer to detect the amount of operation of the lever in the two positive and negative directions, so it is possible to reduce costs compared to the case where two potentiometers are used, and there are fewer failures. can. In addition, if an electrical problem occurs during work by operating the lever, such as disconnection of the electrical wiring to the potentiometer, poor contact or disconnection of the connector, etc., the control means will control the lever in the neutral position. By outputting a signal and immediately returning the control valve etc. to the neutral position,
It is possible to reliably prevent the machine from operating in an unexpected direction, and it is also possible to stop the machine immediately, greatly improving safety.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the device of the present invention, Fig. 2 is a schematic plan view for explaining the positional relationship between the lever and the potentiometer, etc., and Fig. 3 is a schematic plan view for explaining the positional relationship between the cam and the operating direction detection switch. 4 is a schematic block diagram of the control system, FIG. 5 is a block diagram showing a specific example of control by the controller, FIG. 6 is a diagram showing the relationship between the lever operation angle and the output of the potentiometer, and FIG. Figure 9 shows the relationship between lever operation angle and operation force - operation angle and controller output.
The figure is a sectional view showing another embodiment of the invention. 1... Lever 2... Casing (supporting member), 3
x, 3y...arm, 34x, 34y---cam, 3
5x, 35y...potentiometer, 36a, 36b
. 36c, 36d...operation direction detection switch, 5...
Controller, 6... Control valve, 61a. 61b...Solenoid proportional pressure reducing valve.

Claims (2)

[Claims] 1. a lever supported by a support member so as to be rotatable in positive and negative directions from a neutral position; a neutral return spring mechanism that urges the lever to the neutral position; a lever operating direction detection switch;
A potentiometer outputs an electric signal according to the amount of lever operation, and a signal from the operation direction detection switch and a signal from the potentiometer are input to determine whether there is a contradiction between the two signals.If there is no contradiction, An electric control characterized in that the control means outputs a control signal according to the direction and amount of operation of the lever, and when there is a discrepancy, outputs a control signal corresponding to when the lever is in a neutral position. lever device. 2. 2. The electric device according to claim 1, wherein the potentiometer is one, and the lever outputs an electric signal that gradually decreases in proportion to the amount of operation in the negative direction from neutral and gradually increases in proportion to the amount of operation in the positive direction. type control lever device.