JP3606650B2 - Excavator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an excavation work machine.
[0002]
[Prior art]
Conventionally, as one form of excavator, an excavating part is attached to the front end of the swivel base, and the excavating part is attached to the swivel base so that the base end of the boom can be turned up and down, and the base of the telescopic arm is attached to the tip of the boom. There is a type in which an end portion is attached to be freely rotatable up and down, and a bucket is attached to the tip of the arm to be freely rotatable.
[0003]
In such excavation work machines, the telescopic arm can be telescopically operated as necessary to perform excavation work with the bucket, or the cargo can be suspended and loaded with the bucket. I have to.
[0004]
In addition, the excavator is provided with a boom cylinder that moves the boom up and down, an oil passage is provided between the boom cylinder and the hydraulic pump, and an electromagnetic switching valve is installed in the middle of the oil passage. Install a relief valve between the electromagnetic switching valve and the boom cylinder so that when the pressure on the boom cylinder side supporting the boom reaches the relief pressure, the hydraulic oil leaks and the boom naturally descends. The machine is prevented from tipping over.
[0005]
[Problems to be solved by the invention]
However, in the excavation work machine described above, since the telescopic arm can be extended and retracted, when the cargo is suspended by extending the arm and when the cargo is suspended by extending and retracting the arm. The moment that acts on the boom is different, especially when the telescopic arm is extended, the relief pressure is reached immediately, the hydraulic oil leaks, and the boom often drops naturally. There is a problem that it cannot be performed safely and efficiently.
[0006]
[Means for Solving the Problems]
Accordingly, the present invention includes a boom that is pivotably attached to the airframe, a telescopic arm that is pivotally attached to the tip of the boom, and a bucket that is pivotally attached to the tip of the arm. In an excavating work machine provided with an excavating section, an expansion / contraction length detection sensor for detecting the expansion / contraction length of the piston rod of the cylinder is attached to an arm expansion / contraction cylinder that expands / contracts the expansion / contraction arm, and the boom is rotated up and down. An oil passage is installed between the boom cylinder and the hydraulic pump, an electromagnetic switching valve is installed in the middle of the oil passage, and a relief is placed in the middle of the oil passage located between the electromagnetic switching valve and the boom cylinder. Install an electromagnetic relief valve that can change the set value, connect the expansion / contraction length detection sensor to the input side of the control unit, and connect the electromagnetic relief valve to the output side of the control unit. The control unit increases the relief setting value of the electromagnetic relief valve in conjunction with the extension operation of the piston rod of the arm expansion / contraction cylinder, while setting the relief setting of the electromagnetic relief valve in conjunction with the shortening operation of the piston rod of the arm expansion / contraction cylinder. It is an object of the present invention to provide an excavation work machine characterized by reducing the value.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0008]
A shown in FIG. 1 is an excavation work machine according to the present invention. The excavation work machine A is constructed by installing a turning base 2 between a pair of left and right crawler type traveling units 1, 1. The swivel base 3 is mounted on the swivel base 3, the operation unit 4 and the motor unit 5 are provided on the swivel base 3, and the excavation unit 6 is attached to the front end of the swivel base 3. 7 is attached. K is cargo.
[0009]
As shown in FIG. 1, the operation unit 4 has an operation lever column 10 erected at the front of the swivel base 3, and a steering operation lever 11 and various hydraulic cylinder operation levers 12 are attached to the operation lever column 10 and operated. A pedal for arranging a seat 13 behind the lever column 10 and operating a telescopic arm 25 for telescopic arm operation, which will be described later, on the step portion 14 formed between the seat 13 and the operating lever column 10 15 are arranged.
[0010]
As shown in FIG. 1, the excavation part 6 is attached to the front end of the swivel base 3 so that the base end of the boom 16 can be pivoted up and down via a boom mounting bracket 17, and the base of the telescopic arm 18 is attached to the tip of the boom 16. An end portion is attached to be pivotable up and down via an arm mounting bracket 19, and a bucket 20 is pivotally attached to the tip of the telescopic arm 18 via a bucket mounting bracket 21. Reference numeral 22 denotes a boom cylinder for moving the boom 16 up and down, reference numeral 23 denotes an arm cylinder for moving the telescopic arm 18 up and down, and reference numeral 24 denotes a bucket cylinder for rotating the bucket 20.
[0011]
As shown in FIG. 1, the telescopic arm 18 includes a base end side arm forming body 18a attached to the boom 16, and a distal end side arm attached to the base end side arm forming body 18a so as to be extendable and slidable. Formed from the formed body 18b, and an arm extendable cylinder 25 is interposed between the arm formed bodies 18a and 18b so that the distal end side arm formed body 18b can be expanded and contracted by the cylinder 25. .
[0012]
Here, the boom cylinder 22 is provided with a pressure detection sensor 26 for detecting the pressure on the side supporting the weight of the boom 16, and the arm extension cylinder 25 is provided with an extension length for detecting the extension length of the piston rod 25a. As shown in FIGS. 1 and 2, both sensors 26 and 27 are connected to the input side of the control unit 29 disposed in the hood 28 of the prime mover unit 5.
[0013]
Further, as shown in FIG. 2, a boom cylinder 22 and an arm telescopic cylinder 25 are connected to a hydraulic pump P provided in the prime mover unit 5 through oil passages 30 and 31, respectively, A switching valve 32 is installed, an electromagnetic relief valve 33 that can change the relief setting value in the middle of the oil passage 30 located between the electromagnetic switching valve 32 and the boom cylinder 22, and a throttle that decelerates the lowering speed of the boom 16 While installing the deceleration electromagnetic switching valve 34 equipped with the valve 34a, the switching valve 36 is installed in the middle of the oil passage 31, and in the middle of the oil passage 31 located between the switching valve 36 and the arm extension cylinder 25. A locking electromagnetic switching valve 35 having a check valve 35a for locking the expansion / contraction operation of the arm expansion / contraction cylinder 25 is attached.
[0014]
As shown in FIG. 3, the valves 32, 33, 34, and 35 are connected to the output side of the control unit 29.
[0015]
In this way, the control unit 29 increases the relief set value of the electromagnetic relief valve 33 in conjunction with the extension operation of the piston rod 25a of the arm expansion cylinder 25, while in conjunction with the shortening operation of the piston rod of the arm expansion cylinder. The relief set value of the electromagnetic relief valve 33 is decreased, the relief set value is appropriately changed according to the usage form of the telescopic arm 18, and the boom 16 can be reliably rotated up and down, Thus, it is possible to perform work and the like safely and efficiently.
[0016]
When the pressure detection sensor 26 detects a preset danger setting value for preventing the machine from falling, the control unit 29 switches the electromagnetic switching valve 32 for locking to lock the expansion / contraction operation of the arm expansion / contraction cylinder 25. By switching the deceleration switching valve 34 to reduce the lowering speed of the boom 16, it is possible to ensure the safety of the machine and to prevent the machine from falling over. I can do it.
[0017]
Further, as shown in FIGS. 4 and 5, the swivel base 2 is formed with slide supports 2a and 2a extending outward and downward on the left and right sides, and slides into the slide supports 2a and 2a. The body 2b, 2b is slidably inserted, the slide cylinders 2c, 2c are interposed between the slide bodies 2b, 2b and the slide support bodies 2a, 2a, and the leading end of each slide body 2b, 2b is connected to the traveling unit 1 , 1 are attached to the traveling frames 1a, 1a.
1b is a rolling wheel and 1c is a crawler belt.
[0018]
Thus, when the excavation part 6 is arrange | positioned in the direction substantially orthogonal to the advancing direction of the traveling parts 1 and 1, and excavation part 6 is excavated in the same direction, the normal posture shown in FIG. As shown in FIG. 6, the central portion of the traveling unit 1 in the normal posture is changed by changing the posture of the slide body 2b on the excavation operation side to the inclined posture in which the slide body 2b is extended in conjunction with the extension operation of the slide cylinder 2c. The distance H1 from C to the center of gravity G of the airframe is increased to the distance H2, so that the stability of the airframe can be ensured satisfactorily.
[0019]
At this time, since a weight for improving the stability of the airframe is not necessary, the airframe can be reduced in size and a small-swivel excavation work machine can be obtained.
[0020]
In addition, when performing excavation work or earth removal work on an inclined land, the slide bodies 2b and 2b can be appropriately expanded and contracted to perform each work while the swivel base 3 is maintained in a horizontal posture.
[0021]
【The invention's effect】
According to the present invention, the following effects can be obtained.
[0022]
In the present invention, the control unit increases the relief set value of the electromagnetic relief valve in conjunction with the extension operation of the piston rod of the arm extendable cylinder, while the electromagnetic relief valve operates in conjunction with the shortening operation of the piston rod of the arm extendable cylinder. Therefore, the relief setting value is appropriately changed according to the usage type of the telescopic arm, and the boom can be reliably rotated up and down, so that loading and unloading work can be performed. It can be performed safely and efficiently.
[0023]
In addition, when the pressure sensor detects a preset danger setting value to prevent the machine from falling, the control unit switches the electromagnetic switching valve for locking to lock the expansion / contraction operation of the arm telescopic cylinder, and the switching valve for deceleration. Is switched to decelerate the lowering speed of the boom, so that the safety of the machine can be secured satisfactorily and the occurrence of a fall accident of the machine can be reliably prevented.
[Brief description of the drawings]
FIG. 1 is a side view of an excavation work machine according to the present invention.
FIG. 2 is a hydraulic circuit diagram.
FIG. 3 is a control block diagram.
FIG. 4 is a rear view of the excavator.
FIG. 5 is a partially cutaway rear view of a turning base.
FIG. 6 is a rear view illustrating the excavating machine in an inclined posture.
[Explanation of symbols]
A Excavator 1 Traveling unit 2 Swivel base 3 Swivel 4 Driving unit 5 Motor unit

Claims (1)

A boom (16) attached to the machine body so as to be pivotable up and down, an extendable arm (18) attached to the tip of the boom (16) so as to be pivotable up and down, and pivotable to the tip of the arm (18) In an excavating work machine provided with an excavating section (6) having an attached bucket (20), an arm telescopic cylinder (25) for expanding and contracting the telescopic arm (18) is connected to a piston rod ( An expansion / contraction length detection sensor (27) for detecting the expansion / contraction length of 25a) is attached, and an oil passage (30) is provided between the boom cylinder (22) and the hydraulic pump (P) for moving the boom (16) up and down. The electromagnetic switching valve (32) is attached to the middle of the oil passage (30), and the oil passage (30) located between the electromagnetic switching valve (32) and the boom cylinder (22) is halfway. An electromagnetic relief valve (33) capable of changing the relief set value is attached to the section, and the above-mentioned expansion / contraction length detection sensor is installed. The control unit (29) is connected to the input side of the control unit (29), and the electromagnetic relief valve (33) is connected to the output side of the control unit (29). In conjunction with the extension operation of the piston rod (25a) of the cylinder (25), the relief set value of the electromagnetic relief valve (33) is increased, while it is linked to the shortening operation of the piston rod (25a) of the arm telescopic cylinder (25). An excavation work machine characterized in that the relief set value of the electromagnetic relief valve (33) is reduced.

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