JP2001099701A - Loaded weight measuring device of loading vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loaded weight measuring device capable of measuring loaded weight accurately, efficiently in a short time. SOLUTION: In this loaded weight measuring device of a loading vehicle 1 equipped with a boom 2, a hydraulic cylinder 7 for derricking the boom 2, oil pressure detectors 8, 9 for measuring oil pressure P of the hydraulic cylinder 7, and a boom angle detector 6 for detecting a boom angle θ, the oil pressure P of the hydraulic cylinder 7 is sampled over a prescribed sampling time τ, and the sampling is repeated for N times, and sampling weights WN at every N times in each number of sampling time, loaded on a freight loading part 4, are obtained, based on the boom angle θ and an average value Pτat the sampling time τ of the sampled oil pressure P, and the sampling weight WN at N times in the number of sampling times are averaged to calculate the loading weight W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loaded weight measuring device for measuring a loaded weight of a construction machine.

[0002]

2. Description of the Related Art Conventionally, in a loading vehicle such as a wheel loader for loading a load on a transport vehicle such as a dump truck, a load weight detection for measuring and displaying the weight of the load loaded on a load loading portion when the boom is raised. The method is known,
For example, it is disclosed in JP-A-62-274223.

According to the publication, a sensor for detecting that a loading section such as a bucket for loading a cargo has reached a predetermined height position, a hydraulic sensor for detecting the hydraulic pressure of a hydraulic cylinder for lifting the loading section, and Is provided. Then, the hydraulic pressure is sampled at predetermined sampling intervals over a predetermined sampling time before and after the time when the load loading unit reaches a predetermined height position. Based on the average value of the collected hydraulic pressure data, the weight of the load loaded on the load loading section is calculated and displayed.

[0004]

However, the prior art disclosed in Japanese Patent Laid-Open No. 62-274223 has the following problems.

In other words, according to the prior art, even after the loading portion is raised to a predetermined height, the oil pressure is measured for a predetermined sampling time. Therefore, the loading portion is continuously raised until the measurement is completed. There must be. As a result, when a load is loaded on a dump or the like having a low vessel height, the bucket must be raised to a height higher than the height of the vessel for measurement, which takes time and is inefficient. There's a problem.

[0006] Further, if the loading portion stops rising during the measurement, there is a problem that pulsation occurs in the hydraulic pressure of the hydraulic cylinder and measurement accuracy is reduced. Moreover,
If the loading section starts to rise from near the specified height,
Since the measurement is started before the pulsation of the hydraulic pressure due to the start is stopped, there is a problem that the measurement accuracy is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a loading weight measuring device capable of accurately and efficiently measuring a loading weight in a short time.

[0008]

In order to achieve the above object, a first aspect of the present invention is directed to a boom having a loading portion mounted at a distal end thereof, a hydraulic cylinder for raising the boom, and a hydraulic cylinder. In a loading weight measuring device for a loading vehicle equipped with a hydraulic pressure detector for measuring the hydraulic pressure of the vehicle and a boom angle detector for detecting the boom angle, after starting the boom, the hydraulic pressure of the hydraulic cylinder is sampled for a predetermined sampling time. This sampling is repeated the number of times of sampling, and the sampling weight for each number of times of sampling loaded on the loading section is obtained based on the boom angle and the average value of the sampled hydraulic pressure during the sampling time, and the sampling for the number of times of sampling is performed. A controller is provided to calculate the load weight by averaging the weight.

According to the first invention, the hydraulic pressure and the boom angle of the hydraulic cylinder are sampled, for example, N times, and a sampling weight is obtained every N times based on the hydraulic pressure and the boom angle of the hydraulic cylinder, and the sampling weight is averaged. To calculate the loading weight. Therefore, unlike the prior art, the load weight can be measured without the boom passing the predetermined height, and the boom does not need to be raised to a height higher than required for the loading operation. Therefore, working time is shortened,
Work is performed efficiently.

According to a second aspect of the present invention, in the loading weight measuring apparatus according to the first aspect, when the number of times of sampling exceeds a predetermined number of times, the controller averages the sampling weight of the predetermined number of times immediately before the stop of the boom. To calculate the loading weight.

According to the second invention, the controller detects the loaded weight based on the predetermined number of sampling weights counted from the time when the boom stops. Therefore, since the loaded weight is detected based on the hydraulic pressure in which the influence of the pulsation of the hydraulic pressure generated at the time of starting is reduced, the measurement accuracy is improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a wheel loader, and FIG. 2 is a configuration diagram of a loaded weight measuring device installed in the wheel loader. In FIG. 1, a wheel loader 1 is attached to a boom 2 which is rotatable around a boom pin 3 attached to a base end thereof, and is attached to a tip end of the boom 2;
A bucket 4 rotatable around a bucket pin 5. A boom angle detector 6 such as a potentiometer for detecting a lifting angle of the boom 2 (hereinafter, referred to as a boom angle θ) is provided near the boom pin 3. The wheel loader 1 includes a hydraulic cylinder 7 that lifts the boom 2, and the hydraulic cylinder 7 is provided with a head pressure detector 8 and a bottom pressure detector 9 that detect the head pressure and the bottom pressure, respectively. At this time, as shown in FIG. 1, the boom angle θ is the angle of a straight line 19 connecting the boom pin 3 and the bucket pin 5 for stopping the bucket 4 at the end of the boom 2 with respect to a vertical line 18 passing through the boom pin 3. It shall be measured clockwise. That is, the case where the straight line 19 connecting the boom pin 3 and the bucket pin 5 is horizontal is defined as boom angle θ = 90 degrees, and the boom 2 is said to be horizontal.

In FIG. 2, a controller 11 is provided in the wheel loader 1, and the controller 11 is electrically connected to the boom angle detector 6, the head pressure detector 8, and the bottom pressure detector 9. Then, the load weight W of the load loaded on the bucket 4 is calculated from the detected boom angle θ and the differential pressure P between the head pressure and the bottom pressure of the hydraulic cylinder 7 according to a procedure described later. The controller 12 is connected to a display 12 installed in the cab 14 of the wheel loader 1. Display 12
Has a load weight display section 21 for displaying the load weight W of the load.
And a cumulative weight display section 22 for displaying the cumulative weight of the load loaded so far. Further, a printer 13 is connected to the controller 11, and prints out the loaded weight W and the accumulated weight according to an instruction of the print switch 20. The bucket operation lever 23 for operating the bucket 4 includes a cancel switch 15 for invalidating the measurement result of the loaded weight W so as not to be added to the accumulated weight, and a sub total switch 16 for resetting the accumulated weight to zero. Is provided. Further, the cab 14 is provided with a buzzer 17 for notifying an operator that the measurement of the weight of the cargo loaded in the bucket 4 has been completed. These cancel switch 15, sub total switch 16, and buzzer 17 are electrically connected to the controller 11.

Next, a procedure for measuring and displaying the weight of the load loaded on the bucket 4 using the loaded weight measuring device shown in FIG. 2 will be described with reference to the flowchart shown in FIG. Hereinafter, in the flowchart, each step number is denoted by adding S.

The controller 11 first determines whether or not to measure the loaded weight W according to a predetermined procedure described later (S1). When it is determined that the measurement is to be performed, the load weight W is measured according to a predetermined procedure described later (S2). When the measurement is completed (S3), the controller 11 determines the reliability of the measurement data according to a predetermined procedure described below (S4). If the reliability is high, the controller 11 displays the loaded weight W on the loaded weight display section 21 of the display 12. It is displayed in black numbers (S5). If the reliability is low in S4, the loaded weight W is displayed in red numbers (S6). At this time, the controller 11 stores the loaded weight W in both S5 and S6.

Next, the controller 11 sounds the buzzer 17 and notifies the operator that the display of the loaded weight W has been completed (S7). Then, it is determined whether or not the operator has pressed the cancel switch 15 for invalidating the current measurement within the predetermined time with respect to the buzzer 17 (S
8). If the cancel switch 15 is pressed, the controller returns to S1 and waits for the next loading. Also, S8
If the cancel switch 15 is not pressed in
The controller 11 adds the load weight W measured this time to the accumulated weight so far (S9), and displays the new accumulated weight on the accumulated weight display section 22 of the display 12 (S1).
0).

The controller 11 determines whether the sub total switch 16 for resetting the accumulated weight so far has been pressed (S11). If the sub total switch 16 has not been pressed, the process returns to S1. When the sub total switch 16 is pressed, the accumulated weight is set to 0.
Is displayed on the accumulated weight display section 22 (S12). Next, the controller 11 determines whether to print out the calculated loading weight W and the accumulated weight,
Judgment is made based on a command of a printout switch provided in the printer 13 (S13). If there is no printout command, the process returns to S1. The weight is printed out (S14), and the process returns to S1.

Next, the procedure for determining whether or not to measure the load weight W described in S1 will be described in detail with reference to the flowchart shown in FIG. First, the controller 11 determines whether the current boom angle θ is suitable for measurement based on the signal of the boom angle detector 6 (S21). At this time, it is determined that the boom angle θ is appropriate only when both of the following two conditions are satisfied. Condition 1: The current boom angle θ is lower than the boom angle θ at the end of the previous measurement by the first threshold value θt1 or more (that is, the angle is smaller). Condition 2: the boom angle θ is equal to or more than the second threshold value θt2 and equal to or less than the third threshold value θt3.

The above condition 1 prevents the weight measurement from being performed a plurality of times in one raising operation of the boom 2 by confirming that the boom 2 is lower than the time of the previous measurement. Condition 2 prevents measurement during excavation by setting the boom angle θ to be above the second threshold value θt2. At the time of excavation and immediately after that, a pressure difference P several times larger than that at the time of loading is generated in the hydraulic cylinder 7, so that it is difficult to accurately measure the loaded weight W. At the same time, in condition 2, the boom angle θ at the start of measurement is
By making the threshold value θt3 or less, the boom 2
Measurement is not started when is at a high position. That is, when the boom 2 starts measurement from a high position,
The measurement time until the lifting of the boom 2 ends is shortened, and an accurate measurement result cannot be obtained. Therefore, in such a case, the measurement is not performed.

In accordance with the above procedure, if it is determined that the boom angle θ is suitable for measurement, the process proceeds to S22, but if not, no measurement is performed (S26).
The process returns to S1 of the flowchart shown in FIG. Next, S2
In 2, the controller 11 determines, based on the signal of the boom angle detector 6, whether or not the angular velocity of the boom 2 within a predetermined measurement time is suitable for measurement. At this time,
If the boom angular velocity is not 0 rad / sec, it is determined that the angular velocity range of the boom 2 is OK. That is, by performing measurement only when the boom 2 is moving, it is possible to prevent the load weight W from being redundantly detected when the boom 2 is stopped. Then, in S22, the angular velocity of the boom 2 is OK.
If determined to be, the process proceeds to S23, but if NG, it is determined that measurement is not performed, and the process returns to S1 of the flowchart shown in FIG.

Next, in step S23, the controller 11 determines the direction in which the boom 2 moves in a predetermined time based on the signal of the boom angle detector 6. If the boom 2 is raised, it is determined that the operation direction of the boom 2 is OK, it is determined that measurement is possible (S24), and the process proceeds to S2 of the flowchart shown in FIG. Start measurement. If the boom 2 is moving downward in S23, it is determined that measurement is impossible, and the process returns to S1 in the flowchart shown in FIG. That is, the measurement is performed only when the boom 2 is raised, thereby preventing the overlapping detection of the loaded weight W when the operation of lowering the boom once raised is performed. In addition, it is possible to prevent the boom 2 from moving up and down due to vibration when the load is loaded on the boom 2 and the wheel loader 1 travels, so that it is possible to mistakenly assume that the boom 2 has been lifted and to measure the load weight W repeatedly. are doing.

Next, the outline of the means for measuring the load weight W will be described first. FIG. 5 shows a temporal transition of the differential pressure P between the head pressure and the bottom pressure when the wheel loader 1 raises the boom 2. The operator sets the time S
It is assumed that the boom 2 is activated at R and the boom 2 is stopped at time SP. At this time, in the vicinity of time SR, the differential pressure P pulsates violently due to the start-up.
Does not detect the differential pressure P until a predetermined time m0 has elapsed from the time SR and the differential pressure P has settled. Then, from time M1 at which a predetermined time m0 has elapsed from time SR, differential pressure sampling for detecting the differential pressure P at predetermined sampling intervals is repeated N times over a sampling time τ. Then, the detected differential pressure P is converted to the sampling time τ.
On average for each, the average differential pressure Pτ1, Pτ2, Pτ3 ...
Ask for. That is, in the example shown in the figure, differential pressure sampling is performed four times, and the average differential pressure P
That is, τ1 to Pτ4 have been obtained. Before the fifth (N = 5) differential pressure sampling ends, time S
At P, the boom 2 is stopped.

Further, the controller 11 continuously detects the boom angle θ from time SR based on the output signal of the boom angle detector 6. At this time, as shown in FIG.
Assuming that a time at which a predetermined sampling time τ has elapsed from the time M1 is time M2, M3, M4,..., The controller 11 calculates time m from time M1, M2, M3,.
The average boom angles θ1, θ2, θ3,... At times m1, m2, m3,. The average boom angles θ1, θ2, θ3,... Are set as the boom angles θ at the time of each differential pressure sampling. FIG. 6 shows an example of the relationship between the boom angle θ and the average differential pressure Pτ for each loading weight W. In the figure, curves A, B, and C show the cases where the bucket 4 is empty, half loaded, and fully loaded, respectively. That is,
Based on a graph of the relationship between the boom angle θ and the average differential pressure Pτ at two or more loaded weights W measured in advance, as shown in FIG. 7, the relationship between the loaded weight W and the average differential pressure Pτ for each boom angle θ Can be obtained. Therefore, when the boom angle θ and the average differential pressure Pτ are known, the sampling weight WN at each differential pressure sampling can be obtained. For example, at a certain time mk, the boom angle θ = θk,
Assuming that the average differential pressure Pτ = Pτk, the sampling weight WN can be obtained from FIG. Or,
It is also possible to obtain the sampling weight WN based on a numerical table storing such a relationship in advance.

Then, the controller 11 obtains the sampling weight WN at the time of n-time differential pressure sampling before the time SP at which the movement of the boom 2 stops, and calculates the load weight W by averaging the sampling weights WN. For example, as shown in the figure, it is assumed that the sampling is completed at the sampling frequency N = 4, and at this time, if n = 3, the sampling frequency N
= 2 to 4 are obtained at the time of differential pressure sampling, and the load weight W is calculated by averaging these weights. At this time, if the time from the end of the last differential pressure sampling to the time SP is less than m0, the sampling weight WN in the last differential pressure sampling is not adopted. This is because the boom 2 immediately before stopping is considered to be in a deceleration state.
The head pressure in the hydraulic cylinder in the decelerated state rises independently of the loaded weight W, and it becomes difficult to accurately measure the loaded weight W. Therefore, by invalidating the sampling weight WN in such a case, the error of the loading weight W is reduced.

Next, the procedure for measuring the load weight W will be described with reference to FIG.
This will be described in detail with reference to the flowchart shown in FIG. In the flowchart of FIG. 2, two parallel horizontal lines indicate the same time, and between these two lines, each step proceeds in parallel.

First, the controller 11 determines whether or not to measure the loaded weight W according to the procedure described in the flowchart of FIG. That is, this step corresponds to S1 in the flowchart of FIG. If the measurement is possible in S1, the process proceeds to S31 to S35. These steps correspond to time M1 to time M1 in FIG. 5, and during this time, measurement of differential pressure P is not performed. First, the controller 11 sets a counter N indicating the number of times of sampling to 0 (S31), and simultaneously starts a timer for a time m0 (S32). During this time, the detection of the boom angle θ is continued (S3
3). When the time m0 has elapsed, the angle change Δθ of the boom angle θ during the time m0 is stored (S34). In addition, stop determination 1 is performed during the progress of these steps, and it is determined whether or not to continue the measurement (S35). At this time, stop judgment 1 is
Only when both of the following two conditions are satisfied, the measurement is continued until time M1. If any one of these conditions is not satisfied, the process returns to S1. Condition 3: The angle change Δθ of the boom 2 during the time m0 is larger than a predetermined angle change. Condition 4: The transition of the boom angle θ during the time period m0 is always in the direction in which the boom 2 rises.

Condition 3 is such that measurement is not performed when the boom 2 is slowly raised. That is, when the boom 2 is slowly raised, the head pressure in the hydraulic cylinder increases irrespective of the loaded weight W due to the characteristics of the control valve in the hydraulic pipe, and it becomes difficult to measure the loaded weight W accurately. It is because it becomes. Condition 4 is
By not measuring when the boom 2 descends,
Prevents duplicate measurements.

Next, the controller 11 performs steps S41 to S52.
, The differential pressure P is sampled over the sampling time τ, and the boom angle θ at the intermediate time m1 is detected. That is, these steps correspond to time M1 to time M2 in FIG. First, the counter N is incremented by 1 (S41), and a timer for a time τ / 2 is started (S42). During this time, the boom angle θ is continuously detected (S43),
The angle change Δθ of the boom angle θ during the time τ / 2 is stored (S44). Further, a stop determination 2 is made while these steps are in progress to determine whether to continue the measurement (S
45).

At this time, if all of the following three conditions are satisfied, the stop determination 2 continues the measurement until time m1. Condition 5: boom angle θ is equal to or smaller than fourth threshold value θt4. Condition 6: The angle change Δθ of the boom 2 during the time τ / 2 is larger than a predetermined angle change (same as the above condition 3). Condition 7: change rate of boom angle θ (= angle change Δθ during latest time τ / 2 / angle change Δθ during previous time τ / 2)
Is greater than or equal to a predetermined value.

The condition 5 is a condition for stopping the measurement when the boom 2 rises. Since the measurement is started from the angle where the boom angle θ is equal to or less than the third threshold value θt3 under the condition 2, it is considered that if the boom 2 rises to the fourth threshold value θt4, a sufficient number of differential pressure samplings can be performed. I have. At this time, the fourth threshold θt4 may be an angle at which the differential pressure sampling can be performed three times from the third threshold θ3 when the boom 2 is raised at the high idle. Condition 7 is to terminate the measurement when the rise of the boom 2 is decelerating. During deceleration, the above condition 3
Similarly to the above, the head pressure in the hydraulic cylinder rises irrespective of the load weight W, and it becomes difficult to accurately measure the load weight W. In such a case, the measurement is terminated to avoid the occurrence of an error. Then, when the measurement is completed by the stop determination in S45, it is determined that the measurement value during the immediately preceding time τ is invalid, and the process proceeds to S71.

If the counter N indicating the number of times of sampling is 1 or 2 in S71, it is determined that a sufficient measurement time has not been given after the start of the boom 2, and the measurement of the current loading weight W is invalidated. Return to S1. If the counter N is 3 or more, the boom angle θ at the time of stop is stored (S72), and the case is classified by the counter N (S73 to S75). That is, if N = 3, go to S91; if N = 4, go to S92; if N = 5, go to S91.
93, and if N> 5, the process proceeds to S94. These S91 to S94 will be described later.

At time m1, the controller 11
The timer for the time τ / 2 is started (S46). During this time, the boom angle θ is detected (S47), and the angle change Δθ of the boom angle θ during the time τ / 2 is stored (S48). Further, a stop judgment 2 is made while these steps are in progress,
It is determined whether to continue the measurement (S49). In S49, when all of the above-mentioned conditions 5 to 7 are satisfied, the measurement is continued until time M2. During the sampling time τ, the controller 11 samples the differential pressure P at a predetermined sampling interval (S5).
0). Then, the differential pressure P sampled during the time τ,
And the sampling weight WN is calculated from the boom angle θ at the time m1 (S51), and this is stored (S52).

If the measurement has been completed by the stop judgment in S49, it is determined that the measurement value for the immediately preceding time τ is valid, and the flow shifts to S81. In S81,
If the counter N indicating the number of times of sampling is 1, it is determined that a sufficient measurement time has not been given after the start of the boom 2, and the measurement of the current loaded weight W is invalidated, and the process returns to S1. If the counter N is 2 or more, the boom angle θ at the time of stop is stored (S82), and the case is classified by the counter N (S83 to S85). That is, if N = 2, go to S91; if N = 3, go to S92.
If N = 5, go to S93, and if N> 4, go to S93
Go to 95.

After the end of differential pressure sampling, the controller compares the number of samplings N with 7 in S61,
If it is less than 7, steps S41 to S52 are repeated. At this time, the time M1 is M2, M3,.
.., The time M2 is M3, M4,..., And the intermediate time m1 is m2, m3,. In S61, if the number of times of sampling N is 7, the controller 11 determines that the measurement is completed, and performs the steps of S62 to S66. That is, the counter N is incremented by 1 (S62), and the timer for the time τ / 2 is started (S63). During this time, the boom angle θ is detected (S6
4) The angle change Δθ of the boom angle θ during the time τ / 2 is stored (S65). In addition, stop determination 2 is performed during the progress of these steps (S66), and it is determined whether or not the sampling weight WN of the differential pressure sampling immediately before the end of the measurement is valid. That is, if all of the above conditions 5 to 7 are satisfied in S66, it is determined that the data is valid, and the process proceeds to S95. If any of the conditions is not satisfied, the last data is determined to be invalid. Proceed to S94.

In S91, the effective sampling weight WN stored in the controller 11 is only the sampling weight W1. Therefore, the controller 1
1 displays W1 as the loading weight W. In S92, the controller 11 stores an effective sampling weight W
1, W2 are stored. Therefore, the controller 1
1 calculates the average value of W1 and W2 and displays it as the loaded weight W. In S93, the controller 11 stores the effective sampling weights W2 and W3. Therefore, the controller 11 sets the sampling weights W2 and W
The average value of the load weight 3 is calculated and displayed as the load weight W. S
At 94, three or more valid sampling weights WN are stored. The controller 11 employs three (= n) pieces of data from those effective sampling weights WN that are closer to the stop time SP of the boom 2. That is, the average value of W (N−4) to W (N−2) is calculated and displayed as the loaded weight W. In S95, three or more effective sampling weights WN are stored. The controller 11 employs three pieces of data from among those effective sampling weights WN that are closer to the time when the boom 2 stops. That is, W (N-3)
ＷW (N−1) is calculated and displayed as the loaded weight W.

At this time, S73 to S75, S83 to S8
5 and S91 to S95 correspond to the reliability determination of the measurement data in S4 in the flowchart of FIG. That is, in S91, since only one effective sampling weight WN is obtained at this time, the reliability is determined to be low (S102), and the loaded weight W is displayed in red (S6). In S92 to S95, since a plurality of effective sampling weights WN have been obtained, it is determined that the reliability is high (S101), and the loading weight W is displayed in black (S5).

As described above, according to the present embodiment,
The controller 11 samples the differential pressure P and the boom angle θ of the hydraulic cylinder 7 from the start of the rise of the boom 2 over a predetermined sampling time τ to obtain a sampling weight WN. Then, such sampling is repeated, for example, N times, and the loaded weight W is calculated by averaging the sampled weight WN. Therefore, even if the boom 2 does not pass the predetermined height as in the prior art, the load weight W
Can be measured, and it is not necessary to raise the boom 2 to a height higher than that required for the loading operation, so that the operation time is shortened and the operation is performed efficiently.

Further, the controller 11 detects the loaded weight W based on the sampling weight WN of a predetermined number of samplings counted from the time when the boom 2 stops.
That is, since the detection is performed based on the differential pressure P before the boom 2 stops, the influence of the pulsation of the hydraulic pressure of the hydraulic cylinder 7 generated when the boom 2 starts is reduced, and the measurement of the loaded weight W becomes accurate. . Further, the sampling weight WN at a predetermined time m0 immediately after the start of the boom 2 is invalidated. Accordingly, the influence of the pulsation of the hydraulic pressure immediately after the start of the boom 2 is reduced, and the measurement of the loaded weight W becomes accurate. When the boom 2 stops within a predetermined time (time m0 in the embodiment) after the differential pressure sampling is completed,
The immediately preceding sampling weight WN is invalidated. Since the boom 2 is decelerated before the stop, the head pressure in the hydraulic cylinder increases irrespective of the loaded weight W, and it becomes difficult to accurately measure the loaded weight W. Therefore, by invalidating the sampling weight WN at the time of deceleration, the measurement of the loading weight W becomes accurate.

Further, when the boom 2 is out of the predetermined angle range, the detection is not performed. Accordingly, it is possible to avoid measuring the load weight W during excavation or running when a force other than the load weight W is applied to the hydraulic cylinder 7, and thus the measurement of the load weight W becomes accurate. Also, boom 2
The detection is not performed when the robot moves down or moves at a very slow angular velocity. Thus, the detection of the load weight W in one loading operation can be prevented from being detected repeatedly, so that the measurement of the load weight W becomes accurate.

In the embodiment, the differential pressure P of the hydraulic cylinder 7 is
Has been described to measure the loaded weight W, but only the bottom pressure may be detected to reduce the number of detectors and simplify the configuration of the loaded weight measuring device.
In addition, the cumulative weight is described by adding the load weight W, but, for example, when a load is put in a hopper or the like, the total weight is displayed in advance, and the load weight W is subtracted. To

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a wheel loader according to an embodiment.

FIG. 2 is a configuration diagram of a loaded weight measuring device.

FIG. 3 is a flowchart showing a procedure for performing weight measurement and display.

FIG. 4 is a flowchart showing a procedure for determining whether to perform weight measurement.

FIG. 5 is a graph showing a temporal change of a differential pressure.

FIG. 6 is a graph showing a relationship between a boom angle and a differential pressure for each load weight.

FIG. 7 is a graph showing a relationship between an average differential pressure and a load weight at a certain boom angle.

FIG. 8 is a flowchart showing a detailed measuring procedure of a loaded weight.

FIG. 9 is a flowchart showing a detailed measurement procedure of a loaded weight.

[Explanation of symbols]

1: wheel loader, 2: boom, 3: boom pin,
4: bucket, 5: bucket pin, 6: boom angle detector, 7: hydraulic cylinder, 8: head pressure detector, 9: bottom pressure detector, 11: controller, 12: display, 13: printer, 14: operation Room, 15: Cancel switch, 16: Subtotal switch, 17: Buzzer, 18: Vertical line, 19: Straight line, 20: Print switch, 21: Load weight display section, 22: Cumulative weight display section, 2
3: Bucket operating lever.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masamichi Ueda 2597 Shinomiya, Hiratsuka-shi, Kanagawa Prefecture Komatsu Ltd. Electronics Business Unit

Claims (2)

[Claims] 1. A boom (2) having a loading portion (4) attached to a tip thereof, a hydraulic cylinder (7) for raising the boom (2), and a hydraulic pressure (P) of the hydraulic cylinder (7). Oil pressure detector (8,9)
And a boom angle detector (6) for detecting a boom angle (θ) .In the loading weight measuring device of the loading vehicle (1), after starting the boom (2), the hydraulic pressure of the hydraulic cylinder (7) is (P) is sampled over a predetermined sampling time (τ), this sampling is repeated a number of times (N) times, and the boom angle (θ) and the average value (Pτ) of the sampled hydraulic pressure (P) at the sampling time (τ) The sampling weight (WN) for each number of samplings (N) loaded on the loading section (4) is calculated based on the above, and the sampling weight (WN) for the number of samplings (N)
A loading weight measuring device for a loading vehicle (1), comprising a controller (11) for calculating a loading weight (W) by averaging the weights. 2. The load weight measuring device according to claim 1, wherein the controller (11) performs the predetermined number of times immediately before the stop of the boom (2) when the number of samplings (N) exceeds the predetermined number of times. A load weight (W) calculated by averaging a sampling weight (WN) of the load weight.