JP4450592B2 - Operation device, construction machine, and operation signal output method - Google Patents

Description

  The present invention relates to an operating device and an operation signal output method using a potentiometer, and a construction machine including the operating device.

  An operation device using a potentiometer for detecting the operation position of an operation lever is known. In this operating device, a voltage is applied to both ends of the fixed terminal of the potentiometer to detect the voltage of the movable terminal. The detected voltage is converted into an operation amount signal of the operation lever and output. When the detected voltage of the movable terminal is ½ of the voltage applied to both ends of the fixed terminal, the operation lever is determined to be in the neutral position (see Patent Document 1).

Japanese Utility Model Publication No. 6-75022

  However, there is a possibility that the voltage of the movable terminal at the neutral position of the operation lever may fluctuate due to uneven wear of the resistance band of the potentiometer. In this case, although the operation lever is not operated, the voltage fluctuation is converted into an operation amount signal of the operation lever and output.

(1) An operating device according to a first aspect of the present invention has an intermediate terminal and a movable terminal, and the movable terminal slides on a resistance band, and the movable terminal is driven when an operation force is inputted. The operation means, the voltage comparison means for detecting and comparing the voltages of the intermediate terminal and the movable terminal, and when the voltage difference occurs between the voltage of the intermediate terminal and the voltage of the movable terminal compared by the voltage comparison means. Comprises an operation signal output means for outputting a signal indicating the operation amount of the operation means based on the voltage difference, a storage means for storing the voltage of the intermediate terminal as a reference value, and a voltage of the intermediate terminal stored in the storage means An intermediate terminal voltage management means for comparing the current intermediate terminal voltage detected by the voltage comparison means and instructing the display means to display maintenance information when the difference exceeds a predetermined value; It is characterized by providing.
(2) The invention of claim 2 is the operation device according to claim 1, wherein the operation signal output means has an absolute value of a voltage difference between the voltage of the intermediate terminal and the voltage of the movable terminal compared by the voltage comparison means. Regardless of the absolute value if it is equal to or less than the first predetermined value, a signal indicating that the operation amount of the operation means is zero is output, and the operation signal output means outputs the voltage of the intermediate terminal compared by the voltage comparison means. If the absolute value of the voltage difference from the voltage of the movable terminal is equal to or greater than the second predetermined value, a signal indicating that the operation amount of the operation means is maximum is output regardless of the absolute value.
(3) The operating device according to the invention of claim 3 has an intermediate terminal and a movable terminal, and the movable terminal slides on the resistance band, and when the operation force is input, the movable terminal is driven. an operation unit, a first voltage detecting means for detecting the voltage of the intermediate terminal, a second voltage detecting means for detecting the voltage of the movable terminal, the voltage of the movable pin detected by the second voltage detecting means, the Operation signal output means for generating and outputting a signal indicating the operation amount of the operation means using the corrected operation signal as a corrected operation signal for the voltage difference from the voltage at the intermediate terminal detected by one voltage detection means And the secular change is monitored based on the change in the voltage of the intermediate terminal detected every predetermined time by the first voltage detecting means, and it is determined that the amount of change from the initial value of the voltage of the intermediate terminal exceeds the predetermined value. Displays information about maintenance And an intermediate terminal voltage management means for instructing the display means to do so.
(4) A construction machine according to a fourth aspect of the invention includes the operation device according to any one of the first to third aspects and an actuator operated by the operation device.
(5) The operation signal output method according to the invention of claim 5 is a method for outputting an operation signal by an output voltage of a potentiometer in which a movable terminal slides on a resistance band. When a voltage difference occurs between the detected voltage of the intermediate terminal and the voltage of the movable terminal, a signal indicating the operation amount is output based on the voltage difference, and the resistance band is worn. The previous intermediate terminal voltage is stored as a reference value, the stored intermediate terminal voltage is compared with the current intermediate terminal voltage, and when the difference exceeds a predetermined value, information on maintenance is output. Features.
(6) According to a sixth aspect of the present invention, in the operation signal output method according to the fifth aspect, if the absolute value of the voltage difference between the compared voltage of the intermediate terminal and the voltage of the movable terminal is equal to or less than the first predetermined value. Regardless of the absolute value, a signal indicating that the operation amount is zero is output, and if the absolute value of the voltage difference between the compared intermediate terminal voltage and movable terminal voltage is equal to or greater than the second predetermined value, the absolute value Regardless of the feature, a signal indicating that the operation amount is maximum is output.
(7) The operation signal output method according to the invention of claim 7 is a method in which an operation signal is output by an output voltage of a potentiometer in which a movable terminal slides on a resistance band. As the operation signal after correcting the voltage difference between the detected voltage of the movable terminal and the detected voltage of the intermediate terminal, a signal indicating the operation amount is generated and output using the operation signal after correction , Based on the change in the voltage of the intermediate terminal detected every predetermined time, the secular change is monitored, and if it is determined that the amount of change from the initial value of the voltage of the intermediate terminal exceeds the predetermined value, information on maintenance is output. It is characterized by that.

(1) According to the invention of claim 1 and claim 5, in simple and convenient structure, without being affected by the uneven wear resistance band of the potentiometer, it can be reliably detected in a neutral state of the operating means. Moreover, according to the invention of Claim 1 and Claim 5, preventive maintenance becomes possible and an operation rate can be improved.
(2) According to the invention of claims 3 and 7, it can be output properly reflect the signal operation amount.
(3) According to the invention of claim 4 can be accurately operations actuators.

---overall structure---
With reference to FIGS. 1-5, one Embodiment which applied the operating device by this invention to the construction machine is described. FIG. 1 is a perspective view showing an external structure of a hydraulic excavator equipped with an operating device according to the present invention. This hydraulic excavator has a traveling body 1 and a revolving body 2 provided on the traveling body 1 so as to be able to swivel. The swivel body 2 is provided with a cab 3, an engine room 4 provided on the rear side of the cab 3, a counterweight 5 attached on the rear side of the engine room 4, and a right side of the cab 3. And an articulated front device 6 including an arm and a bucket (not shown).

  The traveling body 1 includes a pair of left and right crawler belts 1a, and the crawler belts 1a are driven by a travel motor 1b. The turning body 2 is turned with respect to the traveling body 1 by a turning motor (not shown) provided at the center thereof. The boom 61, the arm, and the bucket are rotated by expansion and contraction of a boom cylinder, an arm cylinder, and a bucket cylinder (not shown), respectively. Each of these motors and each cylinder is driven by pressure oil from a hydraulic pump 45 provided in the engine chamber 4.

  The cab 3 is provided with a display monitor 190 for displaying various information and operation levers 110a and 110b. The monitor 190 displays an operating state of the excavator, maintenance information described later, and the like.

  FIGS. 2A and 2B show the appearance of the operation levers 110a and 110b. The operation levers 110 a and 110 b are arranged one by one on the left and right sides of the cab, and are fixed to the lever fixing panel 31 of the cab 3. The operation lever 110 a on the right side of the cab is an operation lever for the bucket and boom 61. When the operation lever 110a is tilted in the front-rear direction, the bucket is operated, and when the operation lever 110a is tilted in the left-right direction, the boom 61 is operated. The operation lever 110 b on the left side of the cab is an operation lever for the arm and the swing body 2. When the operation lever 110b is tilted in the front-rear direction, the arm is operated, and when the operation lever 110b is tilted in the left-right direction, the swing body 2 is operated. The grip 111 of the operation levers 110a and 110b is kept in an upright state by a spring force (not shown) when no operation force is input. The operator can operate the boom 61 and the revolving body 2 as described above by tilting the grip 111 of the operation levers 110a and 110b in the front-rear and left-right directions against the force of the spring. The tilting range of the grip portion 111 is 15 to 20 degrees in the front-rear and left-right directions from the neutral state. Reference numeral 150 denotes a potentiometer described later.

  FIG. 3 is a system block diagram relating to control of the swing motor, boom cylinder, arm cylinder, and bucket cylinder. Since the method of controlling the swing motor and each cylinder is the same, in the following description, the hydraulic control valve used to drive the swing motor, the boom cylinder, the arm cylinder, and the bucket cylinder is referred to as an actuator 200. The operation of will be described. That is, an output signal from the potentiometer 150 is input to the control circuit 160 to generate an actuator operation signal, and this operation signal is input to the actuator 200 via the actuator driver 180, thereby driving the actuator 200. Reference numeral 170 denotes a potentiometer power supply.

  Two potentiometers 150 are provided below the respective operation levers 110a and 110b. One of these two potentiometers 150 detects the operation state of the grip portion 111 in the front-rear direction, and the other detects the operation state of the grip portion 111 in the left-right direction.

  As shown in FIG. 4A, the potentiometer 150 has a resistance band 151 provided on the surface of the substrate 159 and a movable terminal 155 that can move in contact with the surface of the resistance band 151. Fixed terminals 152 and 153 are connected to the back surfaces of both ends of the resistance band 151.

  An intermediate tap 154 is connected to the substantially central back surface of the resistance band 151. The resistance value between the fixed terminal 152 and the intermediate tap 154 and the resistance value between the fixed terminal 153 and the intermediate tap 154 are substantially equal. That is, the resistance value between the fixed terminals 152 and 153 and the intermediate tap 154 is approximately ½ of the total resistance value between the fixed terminals 152 and 153.

  The movable terminal 155 slides on the surface of the resistance band 151 in conjunction with the operation of the operation levers 110a and 110b, that is, the tilt angle of the grip portion 111. When the gripper 111 is tilted in the front-rear direction, one movable terminal 155 of the two potentiometers 150 is driven, and when the gripper 111 is tilted in the left-right direction, the movable terminal 155 of the other potentiometer 150 is driven. In a neutral state in which no operating force is input to the grip portion 111, the movable terminal 155 is positioned on the substantially central surface of the resistance band 151 (FIGS. 4A and 4B). At this time, the movable terminal 155 and the intermediate tap 154 face each other across the resistance band 151.

  The control circuit 160 includes an analog input unit 161, a processing unit 162, and an output unit 163. The analog input unit 161 is provided with a reference voltage input terminal 164, a ground terminal 165, an operation signal input terminal 166, and an intermediate tap voltage input terminal 167. The analog input unit 161 converts an analog signal input to each of the terminals 164 to 167 into a digital signal and outputs the digital signal to the processing unit 162. The reference voltage input terminal 164 is connected to the positive electrode 171 of the potentiometer power supply 170 as described later, and the ground terminal 165 is connected to the negative electrode 172 of the potentiometer power supply 170. The operation signal input terminal 166 is connected to the movable terminal 155 of the potentiometer 150, and the intermediate tap voltage input terminal 167 is connected to the intermediate tap 154 of the potentiometer 150.

  The processing unit 162 performs an operation described later based on the digital signal output from the analog input unit 161 and outputs a signal to the output unit 163. The processing unit 162 includes a nonvolatile memory 162a. The nonvolatile memory 162a stores a value of an intermediate tap voltage described later.

  The output unit 163 outputs a control signal to the actuator driver 180 based on the signal output from the processing unit 162. The output unit 163 outputs a signal for causing the monitor 190 to display maintenance information to be described later, based on the signal output from the processing unit 162.

  A potentiometer power supply 170 having an output voltage of Vs is connected to the potentiometer 150 and the control circuit 160. The positive electrode 171 of the potentiometer power supply 170 is connected to the reference voltage input terminal 164 of the control circuit 160 and the fixed terminal 152 of the potentiometer 150. The negative electrode 172 of the potentiometer power supply 170 is connected to the ground terminal 165 of the control circuit 160 and the fixed terminal 153 of the potentiometer 150. The negative electrode 172, the ground terminal 165, and the fixed terminal 153 are grounded. Therefore, the voltage at the fixed terminal 152 of the potentiometer 150 is Vs, and the voltage at the fixed terminal 153 is zero.

――― Voltage of intermediate tap 154 and voltage of movable terminal 155 ―――
In the neutral state where the operating force is not input to the gripping portions 111 of the operation levers 110a and 110b, as described above, the intermediate tap 154 and the movable terminal 155 are opposed to each other with the resistance band 151 interposed therebetween. Therefore, as shown in FIG. 4C, the voltage Vm of the intermediate tap 154 and the voltage Vp of the movable terminal 155 are substantially equal. When the grip portion 111 is tilted from this state and the movable terminal 155 approaches the fixed terminal 152, the movable terminal voltage Vp becomes higher than the intermediate tap voltage Vm. Conversely, when the movable terminal 155 approaches the fixed terminal 153, the movable terminal voltage Vp becomes lower than the intermediate tap voltage Vm. Further, as the operation amount of the operation levers 110a and 110b increases, the movable terminal 155 moves away from the intermediate tap 154. Therefore, the voltage difference ΔV = Vm−Vp absolute value (| Δ) between the intermediate tap voltage Vm and the movable terminal voltage Vp. V |) increases.

  When a part of the resistance band 151 is partially worn due to the sliding of the movable terminal 155, the resistance value of the resistance band 151 changes. When the wear portion of the resistance band 151 is biased toward any one of the fixed terminals 152 and 153 when viewed from the connection position of the intermediate tap 154, the intermediate tap voltage Vm changes compared to before the wear of the resistance band 151. However, since the movable terminal 155 and the intermediate tap 154 are opposed to each other with the resistance band 151 interposed therebetween as described above in the neutral state where no operating force is input to the grip portion 111, the movable terminal voltage Vp is also the same. It changes and becomes substantially equal to the intermediate tap voltage Vm. Further, the relationship between the tilting direction of the grip portion 111 and the level of the movable terminal voltage Vp with respect to the intermediate tap voltage Vm does not change. Therefore, in the present embodiment, the voltage difference ΔV between the intermediate tap voltage Vm and the movable terminal voltage Vp is used to detect the operation amount of the operation levers 110a and 110b. That is, the voltage difference ΔV between the intermediate tap voltage Vm and the movable terminal voltage Vp is used as the corrected operation signal. Details will be described below.

――― Operation amount detection of control levers 110a and 110b ―――
The operation amount of the operation levers 110a and 110b is input to the analog input unit 161 of the control circuit 160 as a voltage difference ΔV between the intermediate tap voltage Vm and the movable terminal voltage Vp as shown in FIG. Converted to a signal. Then, a comparison operation is performed by the processing unit 162 as follows.

  FIG. 5 is a graph showing the relationship between the position of the movable terminal 155, the movable terminal voltage Vp, and the driving amount of the actuator 200. The thick solid line in FIG. 5 indicates the movable terminal voltage Vp at an arbitrary movable terminal position (the amount of operation of the operation levers 110a and 110b). The thin solid line shows the drive amount of the actuator 200 calculated by the control circuit 160 based on the voltage difference ΔV between the intermediate tap voltage Vm and the movable terminal voltage Vp in relation to the movable terminal position.

  In the neutral state where the operating force is not input to the gripping portions 111 of the operation levers 110a and 110b (the neutral position in FIG. 5), the voltage Vp of the movable terminal 155 is substantially equal to the voltage Vm of the intermediate tap 154 as described above. . Therefore, if the absolute value | ΔV | of the voltage difference ΔV between the intermediate tap voltage Vm and the movable terminal voltage Vp is substantially zero as a result of the comparison calculation in the processing unit 162, the operation levers 110a and 110b are operated. The control signal is output to the output unit 163 by determining that there is no signal.

  Even if the operation levers 110a and 110b are slightly operated to generate the voltage difference ΔV, if the absolute value | ΔV | of the voltage difference ΔV is smaller than the predetermined value V1, the operation levers 110a and 110b are not operated. Judge that. This determination process is called a dead zone addition process, and is a process for preventing the actuator 200 from being driven sharply only by slightly tilting the operation levers 110a and 110b from the neutral position. The predetermined value V1 is a preset value. Thereby, the actuator 200 is not driven when the movable terminal position is within the range of Xa to Xb.

  If the absolute value | ΔV | of the voltage difference ΔV is not less than the predetermined value V1 and not more than the predetermined value V2 as a result of the comparison calculation in the processing unit 162, the control lever 110a, A signal is output to the output unit 163 so as to output a control signal corresponding to the operation amount 110b. When the absolute value | ΔV | of the voltage difference ΔV is equal to the predetermined value V2, the actuator 200 is driven to the upper and lower limits of the movable range. Even if the operation levers 110a and 110b are operated so that the absolute value | ΔV | exceeds the predetermined value V2, the control signal is output to the output unit 163 on the assumption that the absolute value | ΔV | is equal to the predetermined value V2. Is done. This process is called a saturation area addition process, and is a process for electrically regulating the upper and lower limits of the control signal of the actuator 200. The predetermined value V2 is a value set in advance so that the actuator 200 is driven to the upper and lower limits of the movable range even when the intermediate tap voltage Vm varies as will be described later. Thus, even if the movable terminal position does not reach the upper and lower limits of the movable range, if it reaches Xc or Xd, the actuator 200 is driven to the upper and lower limits of the movable range.

  Thus, even when the resistance band 151 is unevenly worn, it is always determined that the operation levers 110a and 110b are not operated in the neutral state where the operation force is not input to the grip portion 111 of the operation levers 110a and 110b. A control signal is output to the actuator driver 180. When the operation levers 110a and 110b are operated, the control signal corrected by the dead zone addition processing and the saturation region addition processing according to the operation amount is output to the actuator driver 180 as the operation amount signal of the operation levers 110a and 110b. Is done.

――― Fluctuation of intermediate tap voltage Vm ―――
As described above, when the resistance band 151 is partially worn due to the sliding of the movable terminal 155, the resistance value of the resistance band 151 changes and the intermediate tap voltage Vm changes. Therefore, in the control circuit 160, the intermediate tap voltage Vm before the resistance band 151 is worn is stored in the nonvolatile memory 162a as a reference value (intermediate tap voltage initial value Vm0). Then, the intermediate tap voltage Vm is compared with the intermediate tap voltage initial value Vm0, and when the absolute value | ΔVm | = | Vm−Vm0 | of the difference exceeds a predetermined value V3, maintenance information that prompts inspection of the operating device. Is output to the output unit 163 so as to be displayed on the display monitor 190. This predetermined value V3 is a preset value. In order to store the detected intermediate tap voltage Vm as the intermediate tap voltage initial value Vm0, a specific command needs to be input from an input device (not shown).

――― Example of fluctuation of intermediate tap voltage Vm and driving amount of actuator 200 ―――
FIG. 6 is an example of a graph showing the relationship between the position of the movable terminal 155, the movable terminal voltage Vp, and the drive amount of the actuator 200 when the resistance band 151 is unevenly worn. In the following description, the state before the resistance band 151 is unevenly worn is simply referred to as before wear, and the state where the resistance band 151 is unevenly worn is simply referred to as after wear. A thick solid line in FIG. 6 indicates the movable terminal voltage Vp at an arbitrary movable terminal position (the amount of operation of the operation levers 110a and 110b) before wear. The thin solid line shows the drive amount of the actuator 200 calculated by the control circuit 160 based on the voltage difference ΔV between the intermediate tap voltage Vm before wear and the movable terminal voltage Vp in relation to the movable terminal position. . A thick two-dot chain line and a thin two-dot chain line are the movable terminal voltage Vp after wear and the driving amount of the actuator 200, respectively.

  Usually, the place where the partial wear of the resistance band 151 occurs is a part of the resistance band 151 that is frequently operated. In the graph of FIG. 6, for ease of explanation, it is assumed that the resistance band 151 from the intermediate tap 154 to the fixed terminal 152 is uniformly worn. Since the resistance band 151 of the portion where the voltage is higher than that of the intermediate tap 154 is uniformly worn, the resistance value of this portion increases uniformly. Therefore, since the voltage drop at this portion increases, the intermediate tap voltage Vm becomes lower than the intermediate tap voltage before wear (intermediate tap voltage initial value) Vm0.

  Since the potentiometer power supply 170 whose output voltage is Vs is connected to the fixed terminals 152 and 153, the voltage of the fixed terminal 152 is Vs and the voltage of the fixed terminal 153 is zero. The voltages of the fixed terminals 152 and 153 are not affected by the wear of the resistance band 151. On the other hand, the intermediate terminal voltage Vm after wear is lower than that before wear. Therefore, when the movable terminal position in FIG. 6 is from the neutral position to the fixed terminal 153 side, the voltage change amount per movement amount of the movable terminal 155, that is, the slope of the graph representing the movable terminal voltage Vp is small. On the contrary, when the movable terminal position is from the neutral position to the fixed terminal 152 side, the voltage change amount per movement amount of the movable terminal 155, that is, the slope of the graph representing the movable terminal voltage Vp becomes large. Therefore, when the movable terminal position is from the neutral position to the fixed terminal 153 side, the amount of movement from the neutral position of the movable terminal 155 necessary to obtain the same voltage difference ΔV = Vm−Vp increases. Conversely, when the movable terminal position is from the neutral position to the fixed terminal 152 side, the amount of movement from the neutral position of the movable terminal 155 necessary to obtain the same voltage difference ΔV = Vm−Vp decreases.

  The relationship between the movable terminal position and the actuator drive amount when the movable terminal 155 is positioned on the fixed terminal 153 side from the neutral position will be described. For example, the actuator driving amount when the movable terminal position is X1 before wear is Y1. Further, an intermediate tap voltage Vm when the movable terminal position before wear is X1, that is, a voltage difference ΔV between the intermediate tap voltage initial value Vm0 and the movable terminal voltage Vp is set to ΔV (X1). That is, in order to obtain the actuator drive amount Y1, the voltage difference ΔV may be ΔV (X1). Since the actuator drive amount is calculated based on the voltage difference ΔV, the voltage difference ΔV only needs to be ΔV (X1) in order to obtain the actuator drive amount Y1 regardless of wear.

  As described above, after wear, the slope of the graph representing the movable terminal voltage Vp is smaller than that before wear. Therefore, in order to make the voltage difference ΔV equal to ΔV (X1), it is movable compared to before wear. The terminal 155 needs to be moved to a position (X2) away from the intermediate tap 154. Since the voltage difference ΔV is expressed by the product of the slope of the graph and the distance from the neutral position of the movable terminal 155, the larger the voltage difference ΔV, the greater the difference in the movable terminal position before and after wear. Become.

  In order for the actuator driving amount to be −100%, the voltage difference ΔV may be V2, as described above. Before wear, the voltage difference ΔV is V2 when the movable terminal position is Xd. After the wear, the voltage difference ΔV becomes V2 when the movable terminal position is Xf.

  As described above, in the example of partial wear shown in FIG. 6, when the movable terminal 155 is positioned on the fixed terminal 153 side from the neutral position, in order to obtain the same actuator driving amount as before wear, the operation lever operation is performed as described above. It is necessary to increase the amount slightly. In the operating device of the present embodiment, even if the absolute value | ΔVm | = | Vm−Vm0 | of the intermediate tap voltage Vm and the intermediate tap voltage initial value Vm0 becomes the above-mentioned predetermined value V3, the actuator drive amount The predetermined values V2 and V3 are set so that is driven to −100% and + 100%.

  When the movable terminal 155 is positioned closer to the fixed terminal 152 than the neutral position, the relationship between the movable terminal position and the actuator driving amount is opposite to the case where the movable terminal 155 is positioned closer to the fixed terminal 153 than the neutral position. It becomes the tendency. That is, since the slope of the graph representing the movable terminal voltage Vp increases, in order to obtain the same actuator drive amount as before the wear, it is necessary to slightly reduce the operation lever operation amount as described above.

  Note that the upper and lower limit positions Xa and Xb of the movable terminal position in the dead zone also differ before and after wear, but the difference is negligibly small. That is, since the value of V1 is small, even if the movable terminal position for making the voltage difference ΔV equal to V1 is compared before and after wear, the difference is slight.

In the example of the uneven wear of the resistance band 151 described above, it is assumed that the resistance band 151 from the intermediate tap 154 to the fixed terminal 152 is uniformly worn. The movable terminal voltage Vp at an arbitrary position changes as follows.
(1) When the movable terminal 155 is located closer to the fixed terminal 152 than the uneven wear point, the movable terminal voltage Vp increases from before the wear.
(2) When the movable terminal 155 is positioned closer to the fixed terminal 153 than the uneven wear location, the movable terminal voltage Vp is lower than before the wear.
(3) As described above, regardless of the uneven wear position, the movable terminal voltage Vp at the neutral position is always substantially equal to the intermediate tap voltage Vm.

――― Explanation by flowchart ―――
FIG. 7 is a flowchart showing the operation of the program executed by the control circuit 160. When an engine switch (not shown) is turned on, a program for performing the processing shown in FIG. 7 is started and executed by the control circuit 160. In step S1, the intermediate tap voltage Vm is detected, and the process proceeds to step S3. In step S3, it is determined whether or not the intermediate tap voltage Vm detected in step S1 is stored as an initial value. That is, it is determined whether or not a specific command is input from an input device (not shown) and an instruction is given to store the intermediate tap voltage Vm detected in step S1 as an initial value. When an affirmative determination is made in step S3, the process proceeds to step S5, and the intermediate tap voltage Vm detected in step S1 is stored as the intermediate tap voltage initial value Vm0.

  If a negative determination is made in step S3, the process proceeds to step S7, where the intermediate tap voltage Vm detected in step S1 is compared with the intermediate tap voltage initial value Vm0 stored in the nonvolatile memory 162a, and the absolute value of the difference | Δ Vm | is obtained and the process proceeds to step S9. In step S9, it is determined whether or not the absolute value | ΔVm | obtained in step S7 exceeds a predetermined value V3. If an affirmative determination is made in step S9, the process proceeds to step S21, and a signal is output to the display monitor 190 so as to display maintenance information that prompts inspection of the operating device.

  If a negative determination is made in step S9, or if step S5 or step S21 is executed, the process proceeds to step S11. In step S11, the movable terminal voltage Vp is detected, and the process proceeds to step S13. In step S13, a voltage difference ΔV between the intermediate tap voltage Vm detected in step S1 and the movable terminal voltage Vp detected in step S11 is calculated, and the process proceeds to step S15. In step S15, a control signal is generated based on ΔV calculated in step S13, such as the dead zone addition processing and saturation region addition processing described above, and the process proceeds to step S17. In step S17, the control signal generated in step S15 is output to the actuator driver 180 as an operation amount signal of the operation levers 110a and 110b, and the process returns.

The operating device of the present invention has the following effects.
(1) Based on the voltage difference ΔV between the intermediate tap 154 of the potentiometer 150 and the movable terminal 155, the operation amount of the operation levers 110a and 110b is detected. When the voltage difference ΔV is 0, it is determined that the operation levers 110a and 110b are in a neutral state. Accordingly, the neutral state of the operation levers 110a and 110b can be reliably detected with a simple structure and without being affected by the uneven wear of the resistance band 151.

(2) When the operation levers 110a and 110b are operated, a voltage difference ΔV is generated between the intermediate tap 154 and the movable terminal 155, and a control signal calculated according to the voltage difference ΔV is transmitted to the operation lever 110a. , 110b is output as an operation amount signal. Thereby, the operation state of the operation levers 110a and 110b can be reliably detected, and the malfunction of the actuator 200 can be prevented.

(3) A signal indicating the operation amount generated based on the movable terminal voltage Vp is corrected and output based on the intermediate tap voltage Vm and the movable terminal voltage Vp. Thereby, a signal appropriately reflecting the operation amount of the operation levers 110a and 110b can be output.
(4) A control signal is generated based on the voltage difference ΔV generated between the intermediate tap 154 and the movable terminal 155, such as performing a dead zone addition process and a saturation area addition process. Accordingly, the actuator 200 is appropriately driven according to the operation amount of the operation levers 110a and 110b.

(5) The intermediate tap voltage initial value Vm0 in a state where uneven wear does not occur in the resistance band 151 is stored, and compared with the intermediate tap voltage Vm during operation of the hydraulic excavator. When the difference between the intermediate tap voltage initial value Vm0 and the intermediate tap voltage Vm exceeds a predetermined value V3, maintenance information is displayed on the display monitor 190. As a result, preventive maintenance can be performed, and sudden machine stoppage can be prevented, so that the operation rate can be improved. In particular, in the case of a long-running equipment machine such as an ultra-large excavator, the effect of improving the operating rate is remarkable.

――― Modifications ――――
(1) In the above description, when the difference between the intermediate tap voltage initial value Vm0 and the intermediate tap voltage Vm exceeds the predetermined value V3, the maintenance information is displayed on the display monitor 190. However, the present invention is not limited to this. For example, the change with time (aging) of the intermediate tap voltage Vm is stored every predetermined time, and the maintenance information is displayed when a predetermined change such as an increase in the change rate of the intermediate tap voltage Vm is observed. Also good. Moreover, you may use together alert | report with an audio | voice with the display of maintenance information.

(2) In the above description, the potentiometer 150 uses the resistance band 151, but the present invention is not limited to this. For example, a potentiometer using a winding may be used as long as it has an intermediate tap.
(3) In the above description, a hydraulic excavator is used as an example of a construction machine, but the present invention is not limited to this. For example, the present invention can be applied to a crane having a hoisting mechanism using a hydraulic motor and a hydraulic cylinder, and an articulated arm working machine having a plurality of arms connected to each other so as to be rotatable.

(4) In the above description, the operated actuator 200 is a hydraulic motor or a hydraulic cylinder, but the present invention is not limited to this. An actuator driven by a driving force other than hydraulic pressure may be used.
(5) You may combine each embodiment and modification which were mentioned above, respectively.

  In the above-described embodiment and its modifications, for example, the operation means corresponds to the operation levers 110a and 110b, and the storage means corresponds to the nonvolatile memory 162a. The voltage comparison means, operation signal output means, intermediate terminal voltage management means, first voltage detection means, and second voltage detection means are realized by the control circuit 160. Furthermore, as long as the characteristic functions of the present invention are not impaired, the present invention is not limited to the device configuration in the above-described embodiment.

It is a perspective view which shows the external appearance structure of the hydraulic shovel carrying the operating device by this invention. It is a figure which shows the external appearance of the operation levers 110a and 110b, (a) is a front view, (b) is a top view. 2 is a system block diagram relating to control of an actuator 200. FIG. It is a figure which shows the general | schematic structure and electrical characteristic of the potentiometer 150, (a) is sectional drawing of the board | substrate 159, (b) is a circuit diagram, (c) is a position and movable terminal voltage of a movable terminal. It is a graph which shows the relationship with an actuator drive amount. It is a graph which shows the relationship between the position of the movable terminal 155, the movable terminal voltage Vp, and the drive amount of the actuator 200. FIG. It is an example of the graph which shows the relationship between the position of the movable terminal 155 when the resistance belt | band | zone 151 carries out partial wear, the movable terminal voltage Vp, and the drive amount of the actuator 200. FIG. 5 is a flowchart showing the operation of a program executed by the control circuit 160.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling body 2 Revolving body 3 Driver's cab 6 Front apparatus 45 Hydraulic pump 61 Boom 110a, 110b Operation lever 111 Gripping part 150 Potentiometer 154 Intermediate tap 155 Movable terminal 160 Control circuit 161 Analog input part 162 Processing part 162a Non-volatile memory 163 Output part 170 Potentiometer power supply 180 Actuator driver 190 Monitor 200 Actuator

Claims (7)

A potentiometer having an intermediate terminal and a movable terminal, the movable terminal sliding on a resistance band;
An operation means for driving the movable terminal when an operation force is input and operated;
Voltage comparison means for detecting and comparing voltages of the intermediate terminal and the movable terminal;
When a voltage difference occurs between the voltage of the intermediate terminal and the voltage of the movable terminal compared by the voltage comparison means, a signal indicating the operation amount of the operation means is output based on the voltage difference. Operation signal output means,
Storage means for storing the voltage of the intermediate terminal as a reference value;
Display means for comparing the voltage of the intermediate terminal stored in the storage means with the current intermediate terminal voltage detected by the voltage comparing means, and displaying information relating to maintenance when the difference exceeds a predetermined value And an intermediate terminal voltage management means for instructing the operation device. The operating device according to claim 1,
If the absolute value of the voltage difference between the voltage of the intermediate terminal and the voltage of the movable terminal compared by the voltage comparison means is equal to or less than a first predetermined value, the operation signal output means, regardless of the absolute value, Outputting a signal indicating that the operation amount of the operation means is zero;
The operation signal output means, regardless of the absolute value, if the absolute value of the voltage difference between the voltage of the intermediate terminal and the voltage of the movable terminal compared by the voltage comparison means is greater than or equal to a second predetermined value, An operation device that outputs a signal indicating that the operation amount of the operation means is maximum. A potentiometer having an intermediate terminal and a movable terminal, the movable terminal sliding on a resistance band;
An operation means for driving the movable terminal when an operation force is input and operated;
First voltage detecting means for detecting the voltage of the intermediate terminal;
Second voltage detecting means for detecting the voltage of the movable terminal;
The corrected operation signal as a corrected operation signal for a voltage difference between the voltage of the movable terminal detected by the second voltage detection means and the voltage of the intermediate terminal detected by the first voltage detection means. Operation signal output means for generating and outputting a signal indicating the operation amount of the operation means using
Based on the change in the voltage at the intermediate terminal detected at predetermined time intervals by the first voltage detection means, the secular change is monitored, and it is determined that the amount of change from the initial value of the voltage at the intermediate terminal exceeds a predetermined value. And an intermediate terminal voltage management means for instructing the display means to display information relating to maintenance. The operating device according to any one of claims 1 to 3,
A construction machine comprising an actuator operated by the operating device. In a method of outputting an operation signal by an output voltage of a potentiometer in which a movable terminal slides on a resistance band,
Detecting and comparing the voltage difference between the intermediate terminal and the movable terminal of the potentiometer,
When a voltage difference occurs between the compared voltage of the intermediate terminal and the voltage of the movable terminal, a signal indicating an operation amount is output based on the voltage difference,
Store the voltage of the intermediate terminal before the resistance band is worn as a reference value,
An operation signal output method comprising: comparing a stored intermediate terminal voltage with a current intermediate terminal voltage, and outputting information related to maintenance when the difference exceeds a predetermined value. The operation signal output method according to claim 5,
If the absolute value of the voltage difference between the compared voltage at the intermediate terminal and the voltage at the movable terminal is equal to or less than a first predetermined value, a signal indicating that the operation amount is zero is output regardless of the absolute value. ,
If the absolute value of the voltage difference between the compared voltage at the intermediate terminal and the voltage at the movable terminal is equal to or greater than a second predetermined value, a signal indicating that the operation amount is maximum is output regardless of the absolute value. An operation signal output method characterized by the above. In a method of outputting an operation signal by an output voltage of a potentiometer in which a movable terminal slides on a resistance band,
Detect the voltage at the middle terminal
Detecting the voltage of the movable terminal;
As the operation signal after correcting the voltage difference between the detected voltage of the movable terminal and the detected voltage of the intermediate terminal, a signal indicating an operation amount is generated and output using the operation signal after correction ,
Based on the change in the voltage of the intermediate terminal detected every predetermined time, the secular change is monitored, and if it is determined that the amount of change from the initial value of the voltage of the intermediate terminal exceeds the predetermined value, information related to maintenance is output. An operation signal output method characterized by:

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