JP3486299B2 - Outrigger device for work vehicle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outrigger device for a working vehicle such as a concrete pump truck with a boom. 2. Description of the Related Art FIG. 5 shows a general concrete pump car with a boom as an example of a working vehicle (hereinafter referred to as a boom car).
The appearance of is shown. When using a boom for concrete pumping, it is necessary to always use the outriggers (usually four locations in the front, rear, left and right, and sometimes additional auxiliary outriggers depending on the machine) as shown in the figure to maintain the stability of the car body. is there. [0003] Outriggers generally extend and retract legs by hydraulic cylinders. Usually, installation of a boom vehicle at a work site is performed by extending and setting the outriggers at the start of work, until the work is completed. Is usually not changed. FIG. 4 is a view showing a general arrangement of an outrigger, a frame, and a boom device. Reference numeral 6 denotes an outrigger leg, 7 denotes an outrigger casing, 8 denotes an outrigger seat plate, 30 denotes a frame, and 40 denotes a frame. Is a turning device for connecting the frame and the boom device, and 41 is a part of the base of the boom device. [0005] A boom vehicle has a weight limit for mounting necessary devices on a truck chassis.
All equipment and devices, such as a pump device, a boom, and an outrigger device, are required to be reduced in weight. In recent years, booms with longer lengths have been produced to meet market needs such as streamlining concrete pumping work and increasing efficiency, and the longer the boom, the more the overturning moment acting on the vehicle body when the boom is extended. I'm just doing it. As a result, it is necessary to increase the width of the outrigger in order to maintain the stability of the vehicle body. However, the outrigger tension is as small as possible in terms of workability at the construction site, ease of handling, and weight reduction. It needs to be narrow. As a result, if the maximum width of the outriggers is reduced to a certain extent, it will be difficult to obtain a perfect grounding state of the outriggers in all extension directions and postures of the boom, and the outriggers on the opposite side of the boom extension direction will rise. Will do. If the outrigger is not fully grounded, the apparent rigidity of the vehicle body will decrease, the boom vibration generated by pulsation during concrete pumping will increase, and workability and safety will decrease, and the boom will shake. In some cases, the metal fatigue of each part of the device progresses and the machine is damaged. SUMMARY OF THE INVENTION It is an object of the present invention to provide an outrigger device for a working vehicle which is configured to be able to automatically prevent some outriggers from floating. According to the present invention, there is provided an outrigger device for a work vehicle having the following structure to solve the above-mentioned problems. That is, in the outrigger device according to the present invention, a stroke sensor that detects a stroke of the cylinder is installed on the hydraulic cylinder for expanding and contracting the outrigger, and a pressure sensor that detects the head-side internal pressure of each hydraulic cylinder is installed. Hydraulic switching valves are individually provided in the hydraulic circuits. If the internal pressure on the head side of a specific hydraulic cylinder falls below a first set value arbitrarily set during the operation, the corresponding cylinder is extended, and when the cylinder is extended from the initial stroke, the head side When the internal pressure rises above an arbitrarily set second set value, the cylinder is shortened to the initial set position. Since the outrigger device according to the present invention is configured as described above, the hydraulic cylinder supporting the outrigger on the opposite side to the extension direction of the boom during operation, for example, by changing the extension direction or posture of the boom. When the load on the hydraulic cylinder head decreases and the internal pressure on the hydraulic cylinder head side falls below a first set value arbitrarily defined, the hydraulic switching valve for cylinder expansion and contraction automatically operates to extend the corresponding cylinder, and the internal pressure on the cylinder head side decreases. Is prevented from falling below a certain level. Also, when each of the hydraulic cylinders for expanding and contracting the outriggers extends from the initial stroke when the work vehicle is installed and the head-side internal pressure rises above a second set value arbitrarily defined, Then, the cylinder expansion / contraction hydraulic switching valve is automatically operated to shorten the cylinder to the initial set position. In this way, in the outrigger device of the present invention, all outriggers can always maintain a perfect ground state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the outrigger device for a working vehicle according to the present invention is applied to a concrete pump truck will be specifically described below with reference to FIGS.
FIG. 1 shows a configuration of a hydraulic circuit in an outrigger device according to one embodiment of the present invention. In FIG. 1, 1 is a hydraulic pump, 2 is a relief valve of a hydraulic circuit, 3 is an oil tank, 4 is a hydraulic switching valve for outrigger expansion / contraction operation, 5 is a hydraulic cylinder for expansion / contraction, 6 is an outrigger leg, 7 is an outrigger case, 8 is an outrigger seat plate, 9 and 10 are pilot check valves, 11
Denotes a stroke sensor, 12 denotes a pressure sensor, and 13 denotes a hydraulic piping to another hydraulic cylinder circuit for expansion and contraction. The hydraulic cylinder 5 is provided in the leg 6 of the outrigger, and the leg 6 expands and contracts by the expansion and contraction of the hydraulic cylinder 5. A stroke sensor 11 is mounted on the hydraulic cylinder 5, and the amount of expansion and contraction of the cylinder is transmitted as an electric signal. Reference numeral 7 denotes an outer case of the leg 6, which is fixed to the frame 30 on the vehicle body side shown in FIG. 4, and supports a ground reaction force acting on the vehicle body weight acting on the leg 6, a falling moment due to extension of the boom, and the like. Pilot check valves 9 and 10 are provided at the head side and rod side ports of the hydraulic cylinder 5, and the hydraulic cylinder 5 is naturally turned by an external force acting on the hydraulic cylinder 5 (ground reaction force, own weight of the outrigger, etc.). To prevent expansion and contraction. The hydraulic switching valve 4 includes a hydraulic cylinder 5
This is a solenoid valve that controls the expansion and contraction of the. The hydraulic cylinder 5 and peripheral equipment described above are constituted by the number of installed outrigger legs 6 (generally one set for each of the front, rear, left and right, a total of four sets). The expansion and contraction can be controlled independently by the hydraulic switching valves 4 installed in the respective cylinder circuits. A pressure sensor 12 is provided on the head side of the hydraulic cylinder 5, and an internal pressure on the head side of the cylinder is transmitted as an electric signal. The unload relief valve 2 normally returns the pressure oil discharged from the hydraulic pump 1 directly to the oil tank 3 and unloads it. When energized, the solenoid valve 201 of the vent circuit is energized at the same time, the relief valve 2 becomes on-load, and pressure oil is supplied to the hydraulic circuit 101 (this mechanism is a general system, so a more detailed description is omitted. Do). FIG. 2 is a schematic block diagram of the electric control device. In FIG.
Denotes a setter, 23 denotes a start signal, and 24 and 25 denote low-pass filters. As shown in FIG. 2, the outputs of the pressure sensor 12 and the stroke sensor 11 are
1 is fed back through filters 24 and 25. Inside the controller 21, a discriminator for comparing and discriminating a signal fed back from the pressure sensor 12 and the stroke sensor 11 with a value set by the setter 22 is provided.
The solenoid of the hydraulic switching valve 4 is driven by the output based on the determination result, and the expansion and contraction of the hydraulic cylinder 5 is controlled. The discriminator set value can be arbitrarily changed according to the value input by the setter 22. Further, when the start signal 23 is given, the controller 21 replaces the initial value data of the storage device in the controller 21 with the output values of the pressure sensor 12 and the stroke sensor 11 at that time. In the outrigger device of FIGS. 1 and 2 having the above configuration, when the hydraulic switching valve 4 is switched to the B position when the boom vehicle is installed for the pressure feeding operation, the hydraulic oil flows through the pipe 101 to the hydraulic cylinders. 5, the hydraulic cylinders 5 of the respective outriggers are extended, and the seat plates 8 of the respective outriggers touch the ground to lift and stabilize the vehicle body. When the start signal switch (not shown) of the control device is turned on after the setting of the outrigger is completed, a start signal 23 is input to the controller 21, and the signal is used as a trigger to set the stroke mounted on the hydraulic cylinder 5 at that time. Output values of the sensor 11 and the pressure sensor 12 are stored in a storage device of the controller 21. After that, the boom is deployed and the pumping operation is started. If the load acting on the seat plate 8 of the outrigger on the opposite side to the direction in which the boom is extended is significantly reduced due to a change in the posture or extension direction of the boom during the pressure feeding operation, the head of the hydraulic cylinder 5 of the outrigger is reduced. The lateral pressure decreases. As shown in FIG. 3, when the head side internal pressure becomes equal to or less than a first set value (PL1) arbitrarily defined, an output signal is transmitted from a discriminator of the controller 21 and a hydraulic switching valve is provided. 4 is switched to the extension side of the hydraulic cylinder 5, and the hydraulic cylinder 5 expands to stop the reduction of the head-side internal pressure (that is, the floating of the seat plate of the outrigger is prevented). Next, when the load acting on the seat plate 8 on the opposite side to the direction in which the boom is extended increases due to the change in the posture or extension direction of the boom again, the internal pressure on the head side of the hydraulic cylinder 5 of the outrigger is increased. Rises, and when the internal pressure rises to a second set value (PL2) arbitrarily defined, an output signal is transmitted from the discriminator of the controller 21 again,
The hydraulic switching valve 4 is switched to the contraction side of the cylinder, and the corresponding hydraulic cylinder 5 is contracted. However, when the hydraulic cylinder 5 is contracted to the initial stroke (ST0) at the time of installation, the output of the stroke sensor discriminator of the controller 21 is applied to the hydraulic switching valve 4. Energization is OF
At F, the hydraulic switching valve 4 returns to neutral and the hydraulic cylinder 5 stops at that position to support the outrigger. As described above, when the load acting on the outrigger is greatly reduced due to a change in some condition, the hydraulic cylinder 5 is automatically extended to prevent the outrigger from floating, and the extended load on the outrigger is reduced again. When it increases, it automatically returns to the original stroke set at the start of work. The filters 24 and 25 shown in FIG. 2 are low-pass filters, and when the above-described load fluctuations change rapidly and rapidly, the hydraulic cylinder 5 expands and contracts rapidly to exert a vibration action on the vehicle body. Acts to prevent the occurrence of In FIG. 3, PO indicates the initial internal pressure at the time of outrigger setting, and ST1 indicates the maximum length of extension of the cylinder due to a decrease in the internal pressure. As described above, in the outrigger device according to the present invention, the stroke sensor for detecting the stroke of the cylinder is installed in the hydraulic cylinder for expanding and contracting the outrigger, and the head side internal pressure of each hydraulic cylinder is detected. A pressure sensor is installed, and a hydraulic switching valve is individually provided in the hydraulic circuit of each hydraulic cylinder. If the internal pressure on the head side of a specific hydraulic cylinder drops below an arbitrarily set first set value during the operation, the corresponding cylinder Stretches. Then, when the cylinder is extended from the initial stroke, the second pressure on the head side is set arbitrarily.
The cylinder is shortened to the initial set position when it rises above the set value of. Therefore, when the load applied to the outrigger fluctuates significantly due to a change in the extension direction or posture of the boom, etc., it is possible to automatically prevent the outrigger on the side where the load is reduced from automatically extending and the outrigger from rising. . As a result, when a part of the outrigger normally rises due to a decrease in the load, the apparent rigidity of the vehicle body is reduced, thereby increasing the boom vibration caused by the pulsation of the pumping of the concrete pump. In addition to improving the workability and safety of the work, the variable load generated by the vibration of the device is reduced, and the durability and life of each part of the work vehicle device is greatly reduced. Can be extended.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a hydraulic circuit in an outrigger device according to an embodiment of the present invention. FIG. 2 is a control block diagram of the outrigger device according to the embodiment of the present invention. FIG. 3 is a time chart of the outrigger device according to the embodiment of the present invention. FIG. 4 is a configuration diagram of a general frame, outrigger, and boom device. FIG. 5 is an external view of a general concrete pump truck with a boom. [Description of Signs] 1 Hydraulic pump 2 Relief valve for hydraulic circuit 3 Oil tank 4 Hydraulic switching valve 5 for outrigger expansion / contraction operation Hydraulic cylinder 6 for expansion / contraction, Outrigger legs 7 Outrigger case 8 Outrigger seat plate 9, 10 Pilot Check valve 11 Stroke sensor 12 Pressure sensor 13 Hydraulic pipe to other telescopic hydraulic cylinder circuit 21 Controller 22 Setting device 23 Start signal 24, 25 Low pass filter

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B60S 9/00-9/22 B66F 9/00-11/04 B66C 13/00-15/06

Claims (1)

(1) In an outrigger of a working vehicle, a stroke sensor for detecting a stroke of a cylinder is installed in a hydraulic cylinder for expanding and contracting the outrigger, and a head side internal pressure of each hydraulic cylinder is detected. A pressure sensor is installed, and a hydraulic switching valve is individually provided in the hydraulic circuit of each hydraulic cylinder. If the internal pressure on the head side of a specific hydraulic cylinder drops below an arbitrarily set first set value during the operation, the corresponding cylinder Is extended, and when the cylinder side is extended from the initial stroke, when the head side internal pressure rises above a second set value arbitrarily set, the cylinder is shortened to the initial set position. Outrigger device for work vehicles.