JP2002294764A - Backhoe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability by easily recognizing a working status only at a glance during working in a backhoe constituted in a manner that the backhoe can be changed over to an excavation working mode using a front device for normal excavation works and a crane working mode used by working hanging load at the front end of the front device. SOLUTION: In the backhoe with a means detecting the posture of the front device, a means detecting current hanging load, rated load arithmetically operated on the basis of the current detected posture of the front device and a display 33 displaying current detected hanging load, an analog display section is mounted on the display 33, and rated load is displayed by a spot mark ma to an analog scale while hanging load is displayed by a bar mb moved along the analog scale sc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backhoe configured to be switchable between a digging operation mode in which a front device is used for normal digging operation and a crane mode in which a hanging load is applied to the tip of the front device. .

[0002]

2. Description of the Related Art In a backhoe having the above structure, means for detecting the attitude of the front device, means for detecting the current suspension load, and a rating calculated based on the detected current attitude of the front device. A load and a display device for displaying the detected current suspended load are provided, and the rated load and the suspended load are numerically displayed on a liquid crystal display type display device.

[0003]

According to the numerical display, it is suitable for grasping the absolute values of the rated load and the suspended load.
In order to recognize the margin to the rated load and the like, it was necessary to calculate in the head, which was troublesome.

The present invention has been made in view of such a point, and has excellent workability provided with a display device capable of easily visually recognizing the work situation by being instantly visually observed during the work. The purpose is to provide a backhoe.

[0005]

Means for Solving the Problems [Structure, operation and effect of the invention according to claim 1]

(Structure) The invention according to claim 1 is an excavation operation mode in which the front apparatus is used for normal excavation operation,
In a backhoe configured to be able to switch to a crane operation mode in which a hanging load is applied to the tip of the front device, a means for detecting a posture of the front device, a means for detecting a current hanging load, and a detected front To include a rated load calculated based on the current posture of the device and a display device that displays the detected current suspended load,
The display device is provided with an analog display unit, wherein the rated load is displayed as a spot mark on the analog scale, and the hanging load is displayed as a movable mark moving along the analog scale. .

(Operation) According to the above configuration, when the posture of the front device is changed during the crane operation, the rated load capable of safely performing the hanging operation in the posture is calculated based on the detected posture, and this is displayed on the display device. Is displayed as a spot mark located at a predetermined position with respect to the analog scale. Also, the actual hanging load is detected, and this is displayed on the analog display unit as a movable mark. Therefore,
At a glance at the display panel of the display device, the rated load and the suspended load can be recognized as the respective mark positions, and the size of the interval between the two marks can be recognized as a margin.

(Effects) Therefore, according to the first aspect of the present invention, it is easy to intuitively recognize the magnitude of the rated load and the lifting load, particularly the allowance of the lifting operation, which is effective in improving workability. Becomes

[Structure, operation and effect of the invention according to claim 2]

(Structure) According to a second aspect of the present invention, in the first aspect of the present invention, the movable mark for displaying the hanging load is a movable bar.

(Operation / Effect) According to the above configuration, the magnitude of the hanging load can be easily recognized as the length of the bar, and the invention of claim 1 can be suitably implemented.

[Structure, operation and effect of the invention according to claim 3]

(Structure) According to a third aspect of the present invention, in the first or second aspect of the invention, a digital display for numerically displaying the rated load and the hanging load is juxtaposed to the analog display. Features.

(Operation / Effect) According to the above configuration, the correlation between the rated load and the suspension load can be recognized not only on the analog display unit, but also the absolute values of the respective loads can be read. Become.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall side view of a backhoe. This backhoe is mounted on an upper part of a traveling machine base 2 equipped with a pair of right and left crawler type traveling devices 1L and 1R, and a swivel platform 5 equipped with an engine 3 and a driving unit 4 is capable of fully turning around a vertical axis X1. This turntable 5
Is equipped with a front device 9 in which a boom 6, an arm 7, and a bucket 8 are sequentially connected to each other, and an earth removal plate 10 for dozer work is provided at a front portion of the traveling machine base 2. I have.

The left and right traveling devices 1L and 1R are driven to rotate forward and backward by hydraulic motors ML and MR for traveling, respectively, and the swivel 3 is driven to rotate left and right by a hydraulic motor MT for turning. The boom 6, the arm 7, and the bucket 8 of the front device 6 are driven by a boom cylinder C1, an arm cylinder C2, and a bucket cylinder C3, respectively, and the entire front working device 9 is driven by a swing cylinder C4.
The swivel 3 is driven to swing left and right around the vertical axis X2. The earth discharging plate 10 is driven up and down by a dozer cylinder C5.

FIG. 2 shows the entire hydraulic circuit for driving the above-described various hydraulic actuators, and FIG. 3 shows the outline thereof. In the figure, V1 is a control valve for turning, V2 is a control valve for left running, V3 is a control valve for right running, V4 is a control valve for dozer, V5
Is a control valve for the arm, V6 is a control valve for the boom, V7 is a control valve for the bucket, V8 is a control valve for swing, and V9 is a control valve for auxiliary work.
The left and right traveling control valves V2 and V3 are of a manually operated type in which the spools are directly switched and operated by left and right traveling levers 13 disposed in a control tower 12 in front of a driver seat 11, respectively. Control valves V4, V8, V for swing, swing and auxiliary work
9 is an artificially operated type that directly operates the spool by lever operation or pedal operation.
Each of the control valves V1, V5, V6, V7 for the arm, boom, and bucket is of a hydraulic pilot operation type, and a pair of left and right working levers arranged in the control tower 12 so as to be able to perform a cross operation. With the pilot pressure supplied from the pilot valves PV1 and PV2 operated by the valve 14, the opening is adjusted to an opening corresponding to the lever operation amount. The valve block group of the control valves V1 to V9 is connected in parallel with each other together with an inlet block B1 and an outlet block B2, and is connected by an internal oil passage.

A hydraulic oil supply unit 15 having a main pon P1 for working and a pilot pump P2 for supplying pilot pressure.
Are driven by the engine 3. The main pon P1 is of a variable displacement type in which the discharge amount can be changed by changing the angle of the swash plate. After the discharge oil is supplied to the inlet block B1 via the oil passage a, each main control P1 is controlled. It is supplied to valves V1 to V9. Also,
As the pilot pump P2, a gear pump having a constant capacity is used, and the discharge pressure of the gear pump is set via the oil passage b to the unload section 1
9, the pilot valves PV1, PV2
Is supplied to the primary side oil passage c as a pilot source pressure.

As shown in FIG. 4, the unloading unit 19
An unload valve V10 for locking the lever and an unload valve V11 for switching between high-speed running are arranged in parallel. The unload valve V10 is electrically linked to a check lever 27 that opens and closes across the access passage to the boarding operation unit 4. When the access lever is opened by raising the restraint lever 27, the unload valve V10 is opened as shown in the figure. The load position is kept biased, and the primary oil passage c of the pilot valves PV1 and PV2 is held.
Is drained, and a state in which the control valves V1, V5, V6, and V7 cannot be switched by operating the working lever 14, that is, a lever locked state is brought about. After the operator gets on the driver's seat 11 and lowers the check lever 27 to a position crossing the entry / exit passage, this is electrically detected and switched to a position opposite to that shown in the figure, and the primary valves of the pilot valves PV1 and PV2 are switched. The supply of the pilot source pressure to the side oil passage c is performed, and the control valves V1, V5, V
6 and V7 can be switched.

The primary oil passage c of the pilot valves PV1 and PV2 is also connected to an oil passage e for releasing the negative brake NB provided in the turning motor MT.
At the time of lever lock when the unload valve V10 for lever lock is in the unload position, the negative brake N
Since the release oil passage e of B is drained, the turntable 5 is also locked so as not to turn.

The high-speed traveling switching unload valve V11 is used to switch the traveling motors ML and MR to a high-speed state during traveling traveling, and is normally in the unloading position as shown in the figure. Left and right running motors ML,
The MR employs an axial plunger type variable displacement motor capable of shifting between two high and low stages by changing the angle of the swash plate.
It is configured such that “high speed” is provided by supplying pressure oil to 28R, and “low speed” is provided by discharging oil from the cylinders 28L and 28R. And the cylinder 28
Flow path switching valves V12, V13 for controlling the operation of L, 28R
Is connected to the unload valve V11.

According to this, normally, the unload valve V11 is biased and held at the illustrated unload position, and when the pilot oil passage f is drained, the flow path switching valves V12 and V13 operate at the illustrated "low speed". "It is in. When the speed-up pedal 29 provided at the lower side of the control tower 12 is depressed, this is electrically detected, and the unload valve V11 is switched to the reverse position. The switching valves V12 and V13 are switched from the illustrated position to the reverse position. In a state where the flow path switching valves V12 and V13 are switched to the reverse positions, the cylinders 28L and 28R are driven by the hydraulic pressure of the motor driving high-pressure side oil passage,
The motor swash plate is moved to the high-speed position.

The discharge flow rate of the pon P 1 is controlled by a load sensing system, and a flow rate control section 16 is provided adjacent to the pressure oil supply section 15. The flow control unit 16 is provided with a flow compensation valve V14, and the pressure oil supply unit 15 is provided with a flow compensation piston Ac for adjusting the flow rate of the pump P1.
Piston Ac for flow compensation by flow compensation valve V14
Is controlled to operate. Then, the discharge pressure PPS of the main pump P1 and the control signal pressure PLS which takes out the maximum negative pressure from the load detection lines in each section are respectively transmitted via the signal lines L1 and L2 derived from the inlet block B1. The pressure is applied to the flow rate compensating valve V14.
And the control signal pressure PLS is maintained at a set value (control differential pressure) such that the pump P
The discharge flow rate of 1 is controlled.

The load sensing system controls the discharge amount of the pump in accordance with the work load pressure, and discharges hydraulic power required for the load from the pump, thereby saving power and improving operability. In this example, an after-orifice type load sensing system in which pressure compensating valves CV are respectively connected after spools of the control valves V1 to V9 is used.

In this example, the unload valve V15 and the main relief valve V16 of the load sensing system are used.
Are incorporated in the inlet block B1. The control differential pressure set in the flow rate compensating valve V14 in the flow rate control unit 16 is provided by a spring 17 and a differential pressure piston 18 as shown in FIG. When the speed increases and the discharge amount of the pilot pump P2 increases, the control differential pressure component provided by the differential pressure piston 18 increases, and the pump P1
When the rotational speed of the engine 3 decreases and the discharge amount of the pilot pump P2 decreases, the control differential pressure component provided by the differential pressure piston 18 decreases, and the pump P1 The flow rate is controlled by the small eyes.

The backhoe is provided with an automatic idling control system for automatically operating the accelerator device of the engine 3. That is, as shown in FIG. 3, the governor 21 of the engine 3 is operated by an electric actuator 22 such as an electromagnetic solenoid or a motor. An accelerator setting device 24 using a potentiometer provided in 4 and a pressure switch 25 for detecting the pressure of the pilot oil passage g for detecting valve operation are connected.

The pilot oil passage g for valve operation detection is connected in series to the spools of the control valves V1 to V9, and the downstream thereof is connected to the oil discharge passage d. The upstream side is connected via a throttle s to an oil passage h branching out from an oil passage b of the pilot pump P2. Therefore, when all of the control valves V1 to V9 are in a neutral state, the valve operation detecting pilot oil passage g is communicated with the drain oil passage d so that its pressure decreases to almost zero and the control valves V1 to V9 Is operated, the communication of the pilot oil passage g for valve operation detection with the oil drain passage d is cut off, and the oil passage g
Rises to near the original pressure of the pilot pump P2.
Is detected by the pressure switch 25 to determine whether or not the control valve is operated.

Therefore, when the driver sets the accelerator setting device 24 to the high-speed working position, the control valve V
When all of the pressures 1 to V9 are neutral, the pressure oil of the pilot oil passage g for valve operation detection flows out to the oil discharge passage d and drops greatly, so that the pressure switch 25 does not perform pressure-sensitive operation.
In this state, the governor 21 is automatically accelerator-down controlled by the electric actuator 22 to a preset idling position. When the operation is started and any one of the control valves V1 to V9 is operated, the pilot oil passage g for valve operation detection rises, and this is detected by the pressure switch 25. When the pressure switch 25 performs a pressure-sensitive operation, the governor 21 moves the electric actuator 22 to the high-speed position set by the accelerator setting device 24.
Is automatically controlled by the accelerator. That is,
When the front work or running is not performed, the engine speed is automatically reduced to a predetermined idling speed to reduce noise and improve fuel efficiency while the front work or running is not performed.
By automatically increasing the rotation speed to the set rotation speed and supplying necessary hydraulic power, front work or traveling can be efficiently performed.

The backhoe can perform a crane operation using the front device 9 in addition to the original excavation operation. That is, as shown in FIG. 1, a suspension link 31 is pivotally connected to a bracket 8a provided on the back surface of the bucket 8 so as to be rotatable. The suspension link 31 is connected to the front device 9.
When the bucket link 8 is used for normal excavation work
When the crane operation is carried out using the front device 9, the hanging device 32 is swung out at the back of the bucket 8 in the raked position, as shown in FIG. Be attached.

Also, some modifications have been made to the hydraulic system to carry out crane work. That is, as shown in FIG. 5, when the boom 6 moves down, the oil passage t serves as an oil discharge passage from the boom cylinder C1, and when the arm 7 moves down (pulls down), the oil discharge from the arm cylinder C2 occurs. Lock valves RV1 and RV2 are interposed in the oil passage u serving as an oil passage, respectively, so that when the crane operation is performed using the backhoe, the boom 6 and the arm 7 are prevented from unexpectedly descending. . The lock valve RV1 for preventing the boom descent is unlocked by the pilot pressure of the pilot oil passage v for lowering the boom, and the lock valve RV2 for preventing the arm descent is connected to a pilot oil passage for scraping the arm. The lock is released by the pilot pressure of w.

Also, an electromagnetic valve MV is interposed in the pilot oil passage x on the dump side connected to the bucket control valve V7. When the crane mode is selected, the electromagnetic valve MV is shut off, and the scraping posture is set. Of the bucket 12 is not inadvertently dumped.

Further, the following detecting means are provided for crane operation. That is, at the base of the boom cylinder C1 and the base of the arm 11, angle sensors S1 and S2 using potentiometers are provided as means for detecting the attitude of the front device, respectively. A pressure sensor PS is connected to the oil passage on the oil supply side, so that a load pressure generated in the boom cylinder C1 during crane operation is detected. A display device 33 as shown in FIG. 7 is connected to the control device 23. The display device 33 has a horizontally long liquid crystal display panel 34, a crane switch 35 for turning on and off a crane mode, and a display. A display changeover switch 36 for changing the display mode on the panel 34
Is provided.

In the state where the crane mode is selected, the suspension turning radius, which is the horizontal distance from the vertical axis X1 for suspension to the suspension point Y, and the suspension radius The ground height at the lowering point Y is calculated, and the suspending load acting on the suspending point Y is calculated from the load pressure acting on the boom cylinder C1. The load, the calculated current suspension load, the calculated suspension turning radius, the suspension height, and the like are displayed as described below, so that the driver can recognize the current work situation. I have.

The form of display on the display panel 34 will be described below.

In the normal excavation operation mode in which the crane switch 35 is turned off, as shown in FIG. 8, when this switch is pressed, a message for switching to the crane mode is displayed.

When the crane switch 35 is turned on and the mode is switched to the crane mode, the lower part of the display panel 34 becomes an analog display section, and the rated load in the current attitude of the front apparatus is changed to a cross-shaped spot at a predetermined position with respect to the analog scale sc. In addition to being displayed as the mark ma, the current suspension load is displayed as a bar graph that moves along the analog scale sc. The upper side of the analog display section is a character display section, and the absolute values of the rated load and the suspended load are displayed by letters and numbers.

When the display changeover switch 36 is pressed,
As shown in FIG. 9 from the display of FIG. 7, while the analog display is left, the display is switched to a state in which the hanging turning radius (displayed as turning) and the hanging height are displayed in characters, and the display changeover switch 36 is pressed again. Is returned to the display state of FIG.

Then, as shown in FIG. 10A, when the suspended load approaches the rated load (for example, 90 to 90% of the rated load).
100%), the alarm buzzer sounds intermittently,
The alarm lamp flashes. Further, as shown in FIG. 10 (b), when the hanging load exceeds the rated load (100% of the rated load).
% Or more), the alarm buzzer 37 continuously sounds, and the alarm lamp 38 continuously lights to call the driver's attention.

Further, when the attitude of the front device 9 and the above-mentioned sensors are recognized, the following display is performed using the display device 33.

(1) When the boom 6 reaches the upper limit,
Since the correct load pressure cannot be detected by entering the hydraulic cushion area and performing the relief operation, a message prompting the boom lowering operation is displayed as shown in FIG.

(2) When the boom 6 is raised and the arm 7 is extended, the suspending device 32 is in a posture of interfering with the bucket 8, so that when the front device 9 is in such a posture, FIG.
As shown in 1 (b), a message prompting the boom lowering and arm scraping operation is displayed.

(3) Since the lock valve is not provided in the dump direction of the arm 7, depending on the posture of the front device 9, when the hydraulic hose is broken, the arm 7 may descend in the dump direction by its own weight. Therefore, since such a posture of the front device is recognized, a message prompting an arm extending operation is displayed as shown in FIG.

(4) As shown in FIGS. 12 (a) to 12 (g), if there is an abnormality in the sensors, the contents of the abnormality and a message urging the prohibition of the crane operation are displayed alternately, and the alarm buzzer 37 is activated. The alarm sounds continuously while the alarm lamp 38 is lit continuously.

When a plurality of warning items occur at the same time, only one item is displayed in accordance with a priority set in advance, and when the warning item is eliminated, the next item is displayed. For example, the above-mentioned states (1), (2), and (3) have the highest priority. Next, (4) when the suspended load exceeds the rated load, (5) when the suspended load approaches the rated load,
It becomes.

When the crane mode is selected, the above-described auto idling control system is stopped, and the engine speed is set by the accelerator set by the accelerator setting device 24. Moreover, in the crane mode, the upper limit of the accelerator set by the accelerator setting device 24 is limited to a lower rotation than the normal upper limit, and even if the accelerator setting device 24 is inadvertently operated to the maximum rotational speed position in the crane mode, the actual accelerator position is not changed. The set is limited to a preset maximum rotation speed for the crane mode, and it is possible to prevent the front device 9 from operating at a high speed with a load suspended.

[Another Embodiment] In the analog display section of the display device, as the movable mark for displaying the hanging load, in addition to the bar display as described above, a spot-shaped mark different from the spot mark for displaying the rated load is used. Can also be used.

[Brief description of the drawings]

FIG. 1 is an overall side view of a backhoe.

FIG. 2 is an overall hydraulic circuit diagram

FIG. 3 is a schematic diagram of an entire hydraulic circuit diagram.

FIG. 4 is a hydraulic circuit diagram of a traveling and turning section.

FIG. 5 is a hydraulic circuit diagram of a boom, an arm, and a bucket section.

FIG. 6 is a control block diagram.

FIG. 7 is a front view of a display device.

FIG. 8 is a front view showing a display state when the crane mode is switched off.

FIG. 9 is a front view showing a display example in a crane mode.

FIG. 10 is a front view showing a display example in a crane mode.

FIG. 11 is a front view showing a display example in a crane mode.

FIG. 12 is a front view showing a display example in a crane mode.

[Explanation of symbols]

 9 Front device 33 Display device ma Spot mark mb Movable mark sc Analog scale

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B66C 23/90 B66C 23/90 Y (72) Inventor Eiji Nishi 64 Ishizukitamachi, Sakai-shi, Osaka Kubo Co., Ltd. F-term in the Sakai Plant (reference) 2D015 HA03 HB01 HB05 3F205 AA20 BA06 HA06 HC05 HC06 HC07

Claims (3)

[Claims] A backhoe configured to be able to switch between a digging operation mode in which the front device is used for a normal digging operation and a crane mode in which a hanging load is applied to a tip of the front device to change a posture of the front device. Means for detecting, means for detecting the current suspension load, a rated load calculated based on the detected current posture of the front device, and a display device for displaying the detected current suspension load. The display device further includes an analog display unit, and the rated load is displayed as a spot mark on the analog scale, and the hanging load is displayed as a movable mark moving along the analog scale. Backhoe to do. 2. The backhoe according to claim 1, wherein a movable mark for displaying the hanging load is a movable bar. 3. The backhoe according to claim 1, wherein a digital display for numerically displaying the rated load and the suspended load is juxtaposed to the analog display.