JPS624189A - Flexible structure working machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flexible structure working machine suitably used, for example, as a cargo handling machine having a low-rigidity multi-joint structure, and particularly to The present invention relates to a flexible structure work machine that can automatically perform landing work.

[Prior art]

For example, in construction machinery such as cargo handling equipment, multiple long arms are connected to form a multi-jointed mechanism with a total length of 20 to 30 joints because of the need to handle large and heavy objects. In construction machinery, each arm has become larger and heavier, and not only is a large inertial force acting on it, but also the actuator that drives each arm must be larger, leading to a rise in manufacturing costs.

For this reason, there is an increasing need for a work machine with a flexible structure in which each arm is made longer and lighter in weight.

Therefore, FIG. 5 shows an example of a conventional material handling machine having a flexible structure.

In the figure, reference numeral 1 denotes a working machine main body, and the main body 1 consists of a lower traveling body IA and an upper rotating body IB that is rotatably mounted on the lower traveling body LA.

Reference numeral 2 denotes an arm rotatably attached to the front part of the E section rotating body IB, and the arm 2 includes a first arm 3 rotatably connected to the upper rotating body IB with a pin; It consists of a second arm 4 rotatably connected to the tip of the arm 3 with a pin, and each arm 3.4 has a relatively long length and is lightweight, so it can be elastically bent. It is beginning to transform. 5 is a hydraulic cylinder that rotates the first arm 3, and 6 is a hydraulic cylinder that rotates the second arm 4.

Reference numeral 7 denotes a gripping device as a working device that is rotatably connected to the tip of the second arm 4 with a pin, and the gripping device 7 has a pair of gripping portions 7A, 7A, and t. are driven by a hydraulic motor 8 to approach or move away from each other, and grip a load 9 as an object to be worked on.

In the cargo handling machine configured in this way, for example, when lifting the load 9 placed on the ground, the hydraulic cylinder 5.
6 to rotate the first and second arms 3.4 to place the gripping device 7 on the load 9 and drive the hydraulic motor 8 to grip the load 9 between the respective gripping portions 7A. The hydraulic cylinder 5 is gradually extended and the first 7-m 3 is rotated upward to slowly lift the load 9 from the ground to perform the ground cutting operation. When lowering the baggage 9 onto the ground, the hydraulic cylinder 5 is gradually contracted and the first arm 3 is rotated downward to slowly lower the load 9 onto the ground.

By the way, in the cargo handling machine configured as described above, each arm 3, 4 is lightweight, so each arm 3 and 4 is light during operation.
．． In addition to reducing the inertial force acting on arm 3,
, 4 can be downsized, and manufacturing costs can be reduced.

However, in this kind of flexible construction work equipment, each arm 3.4 is made lighter and longer, so the rigidity of each arm 3, 4 is lowered, and the weight of the load 9 causes each arm to become longer. 3 and 4 are easily elastically deformed from straight lines A and B as shown by curves A' and B'. As a result, when the load 9 is lifted up or lowered as quickly as possible when the load 9 is off the ground or landed, each arm 3, 4 is elastically bent, and this reaction causes each arm 3.4 to vibrate. Become. In particular, when landing the baggage 9, the baggage 9 is landed with each arm 3, 4 bent, so unless the landing work is performed by gradually removing this bending, the baggage 9 cannot be held by the gripping device. As soon as the I7 is released, each arm 3, 4 begins to vibrate due to the reaction of the deflection, and this vibration continues for a long time, worsening operability, making it impossible to ensure the safety of one operation, and furthermore, causing damage to the cargo. This may cause load sway and damage accidents.

For this reason, in the conventional technology, the driver operates the hydraulic cylinder 5 at full speed relying on intuition and experience while visually checking the position of the tip of the arm 4 and the position of the cargo 9 to avoid the vibrations described above. However, it has the disadvantage that it can only be operated by an experienced driver, and making ground cutting and landing work extremely troublesome.

[Problem that the invention seeks to solve]

The present invention was made in view of the above-mentioned drawbacks of the prior art, and the problem to be solved by the present invention is to automatically perform ground cutting and landing operations when lifting and lowering a workpiece. To provide a flexible structure working machine which can prevent vibration of an arm and improve operability.

[Means for solving problems]

The configuration adopted by the present invention in order to solve the above-mentioned problems includes at least one arm rotatably provided on the work machine body, a hydraulic cylinder that rotates the arm, and a hydraulic cylinder that rotates the arm based on a command signal. a control valve that controls the flow rate of oil supplied to the hydraulic cylinder; a first signal generating means that outputs a predetermined command signal to the control valve in accordance with the amount of operation of an operating lever that operates the hydraulic cylinder; Attached to the tip of the arm depending on the workpiece! load detection means for detecting the load applied to the load; and a second load detection means for outputting a command signal corresponding to when the workpiece lands or cuts off the ground to the control valve based on the load signal detected by the load detection means. and a signal switching means for selectively connecting the first and second signal generating means to the control valve.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 4.
The explanation will be given by taking a multi-3f1-section cargo handling machine as an example. In the embodiment, the same components as those of the prior art described above are given the same reference numerals, and the explanation thereof will be omitted.

In the figure, reference numeral 11 denotes an operating lever provided in the driver's cab of the L-section rotating body IB. The operating lever 11 is tilted by manual operation by the driver, and is adjusted to a tilting angle in order to extend or contract the hydraulic cylinder 5. A corresponding (proportional) tilt angle signal θ is output. Reference numeral 12 denotes a metering characteristic converter as a first signal generating means that outputs a predetermined command signal S1 to a servo valve 13, which will be described later, in accordance with a tilting angle signal θ of the operating lever 11; The rotation angle signal 0 is metered and converted into a predetermined electric current fii,i (see Fig. 3), and this is used as the command signal Sl to be used in vJit, which will be described later.
It is output to the servo valve 13 via the switch 17. Here, as shown in FIG. 3, the metering characteristic converter 12 according to this embodiment has a tilting angle signal θ of the operating lever ti equal to
Within the range of 0 to θ0, the command signal S! Let the current i of be zero,
The servo valve 13 is closed and the hydraulic cylinder 5 is stopped, while a current i proportional to the tilting angle signal θ is output to the servo valve 13 as a command signal S1 when 0×θ0 or 0>θ0. The opening degrees of the servo valves 13 are adjusted accordingly, and the hydraulic cylinder 5 is contracted or expanded.

Reference numeral 13 denotes a servo valve as a flow rate control valve that controls the flow rate of oil supplied to the hydraulic cylinder 5 based on a command signal S+ from the metering characteristic converter 12 or a command signal S2 described later. is electric-hydraulic conversion valve 1
It is configured to adjust the amount of oil to the hydraulic cylinder 5 based on the command signal Sl or S2, and to control the expansion and contraction speed of the hydraulic cylinder 5. Note that the flow 1 control valve may be replaced with the servo valve 13 and may be a control valve using an electromagnetic proportional valve or the like. A built-in load sensor serves as a load detection means, and the load sensor 14 detects the load applied to the tip of the second arm 4 by the load 9 gripped by the gripping device 7, and detects the load corresponding to the detected load value. The signal F is output to a signal control section 15, which will be described later.

Reference numeral 15 denotes a signal control section as a second signal generating means that outputs a command signal S2 corresponding to when the load 9 lands or leaves the ground to the servo valve 13 based on the load signal F. 4 Based on the function of the load signal F and the current i shown in the figure, the current i according to the load signal F is controlled by the command signal S.
As 2, the servo valve 13 is
F! is output to and supplied to the hydraulic cylinder 5 by automatically controlling the servo valve 13. ! , the amount is adjusted and the hydraulic cylinder 5 is automatically contracted or expanded at a slow speed.

Here, the signal control unit 15 controls the current i of the command signal S2 according to the characteristic 11 shown in FIG. 4 when the load 9 is lowered, and as the load signal F from the load sensor 14 becomes smaller, the command signal S2 The current 1 is decreased to gradually reduce the opening degree of the servo valve 13, thereby slowing down the contraction speed of the hydraulic cylinder 5 and lowering the first arm 3 gradually. Load signal F from
When it reaches a predetermined value Fo, the current i of the command signal S2 is made zero, the servo valve 13 is closed, and the lowering of the first arm 3 is stopped. On the other hand, when lifting the load 9, a constant minute current io is applied until the load signal F from the load sensor 14 reaches a predetermined value FO, as shown by characteristic J12-1.
is output to the servo valve 13 as a command signal S2, the first arm 3 is raised at a very slow speed via the hydraulic cylinder 5, and when the load signal F exceeds a predetermined value FO, the characteristic IL2
-2 of the command signal S2, and as the load signal F increases, the current i is increased to gradually increase the opening degree of the servo valve 13, and the first In Figure 6, numeral 16 denotes a variable setting device for appropriately setting the predetermined value FO according to the type of cargo 9; A function as shown in FIG. 4 is input to the signal control section 15 based on the predetermined value FQ set by .

Further, 17 selectively connects the metering characteristic conversion section 12 and the signal control 1115 to the servo valve 13,
The changeover switch 17 serves as a signal changeover means for inputting the command signal S1 or S2 to the servo valve 13, and the changeover switch 17 is switched from the terminal 17A to the terminal 17B by the driver when the load 9 is off the ground or landed. , the command signal S2 from the signal control part 15 is input to the servo valve 13. On the other hand, during normal operation, it is switched to terminal 17A, and the operating lever 11'+'-
The above change based on dynamic operation! I! Command signal St from section 12
is input to the servo valve 13.

Further, reference numeral 18 denotes an open signal generating unit that outputs an open signal to a servo valve 19, which will be described later, when the current i of the command signal S2 outputted from the signal control unit 15 becomes zero; Each gripping part 7A of the gripping device 7 is supplied with pressure oil.
The servo valve 19 serves as a flow rate control valve for causing the baggage 9 to be gripped or released by the gripping device 7 by moving the baggage 9 toward or away from each other. The baggage 9 is released through the . Further, when a gripping signal is input through an operation means such as an operation button (not shown) during lifting work of the luggage 9, the servo valve 19 drives the hydraulic motor 8 to cause the gripping device 7 to grip the luggage 9. It has become.

Next, the operation of the cargo handling machine configured in one or more ways will be explained.

First, when lifting the baggage 9, a gripping signal is output to the servo valve 19 via an operation means (not shown), the hydraulic motor 8 is driven, and the baggage 9 is gripped by the gripping device 7.

Then, switch the selector switch 17 to the terminal 17B side,
The load 9 is automatically cut off the ground based on the command signal S2 from the signal control section 15. That is, when the weight of the baggage 9 is the value Fl, the signal control unit 15 sends a small signal along the characteristic curve 2-1 until the detected value by the load sensor 14 reaches the predetermined value Fo (where F, <F,). A command signal S2 of current io is output to the servo valve 13, and the servo valve 1
Pressure oil is supplied to the hydraulic cylinder 5 through 3, and the arm 3 of @1 rises at a very slow speed. When the detected value of the load sensor 14 exceeds a predetermined value Fo, a command signal S2
The current i gradually increases along characteristic statement 2-2 in FIG.
arm 3 of is raised at a gradually faster speed, thereby.

Even if the first arm 3 and the second arm 4 are bent, the rising speed of the first arm 3 is controlled so that each arm 3, 4 does not vibrate. And cylinder sensor 1
When the detected value of 4 reaches value F1, which is the weight of baggage 9, the ground cutting work for baggage 9 is completed. /] Replacement switch 17
is switched to the terminal 17A side, and a lifting operation is performed by manually operating the operating lever 11.

On the other hand, when lowering the load 9 to the ground, the first arm 3 is lowered by operating the operating lever 11 via the servo valve 13 and the hydraulic cylinder 5, and the load 9 is placed at a desired height from the ground. , switch the selector switch 17 again to the terminal 17B side. At this time, the detected value of the load sensor 14 is a value F1 which is the weight of the luggage 9, and the current 1 shown in FIG.
1 command signal S? is from the signal control W section 15 to the servo valve 13
is output to. As a result, the hydraulic cylinder 5 is contracted via the servo valve 13 and the first arm 3 is automatically lowered at a slow speed. And the moment baggage 9 touches the ground,
Since the detected value of the load sensor 14 becomes smaller than the value F1, the current i of the command signal S2 gradually decreases along the characteristic line l in FIG. The first arm 3 gradually descends at a slow speed to gradually reduce the deflection of the first and second arms 3 and 4 due to the load 9, and to prevent each arm 3 and 4 from vibrating. The descending speed of arm 3 of No. 1 is controlled. Then, at the stage when the detected value of the load sensor 14 reaches the predetermined value FO, the landing work of the cargo 9 is substantially completed, the electric currents tIi, i of the command signal S2 become zero, and the signal generator 18 generates a release signal. The load is output to the servo valve 19 and the load 9 is released from the gripping device 7.

Thus, according to this embodiment, the signal control section 15 can automatically control the servo valve 13 by simply switching the changeover switch 17 to the terminal 17B side when the cargo 9 is off the ground and when it lands. , i' of the load 9 so as not to cause vibrations in the second arm 3.4. ! ! Cutting work and landing work can be performed automatically, and operability can be reliably improved. Additionally, work that conventionally relied on the skill of the driver can be automated, and safety can be reliably improved.

In the above embodiment, the hydraulic motor 8 is used to drive each gripping part 7A of the gripping device 7, but
Instead of this, a hydraulic cylinder may be used. Furthermore, the gripping device 7 may be a hook. In this case, the hook may be attached to or detached from the load 9 manually by the worker, and the hook may be attached to or detached from the load 9 by the signal generator 18 or the servo valve 1.
9, hydraulic motor 8, etc. can be omitted.

Further, in the embodiment, the load sensor 14 is connected to the second arm 4.
Although it has been described that the second arm 4 is built in the pin connecting portion between the tip of the second arm 4 and the gripping device 7, the load applied to the tip of the second arm 4 may be detected using a known load cell or the like instead.

Furthermore, although the above embodiments have been described using a cargo handling machine as an example, the present invention is not limited to this, and can be applied to other working machines having a flexible structure, such as a hydraulic crane.

In this case, the arm 2 may be composed of one or three or more arms. Furthermore, in addition to the first arm 3, the hydraulic cylinder 6 of the second arm 4 is connected to the servo valve 13 during landing work. Pressure oil may be supplied and discharged, or more generally, pressure oil may be supplied and discharged from the servo valves 13 to the hydraulic cylinders 5 and 6, respectively.

〔Effect of the invention〕

As detailed above, according to the present invention, when the workpiece lands on the ground or leaves the ground, the signal switching means is switched, and the command signal corresponding to the load value detected by the load detection means is sent from the second signal generation means. Since the signal is output to the servo valve, the servo valve can be controlled by the second signal generating means according to the detected value of the load detecting means, and the flow is controlled so that each front arm does not vibrate. It is possible to automatically raise or lower the vehicle and perform landing or cutting operations, thereby reliably improving operability and safety.

[Brief explanation of drawings]

1 to 4 relate to embodiments of the present invention, FIG. 1 is an overall view of the cargo handling machine, and FIG.
FIG. 3 is a metering characteristic diagram generated in the metering characteristic conversion section in FIG. 2. FIG. FIG. 4 is a diagram showing functions generated in the signal control section in FIG. 2, and FIG. 5 is an explanatory diagram of a conventional cargo handling machine. l...Main body, 3...First arm, 4...Second arm, 5, 6...Hydraulic cylinder, 7...Gripping device, 9...Luggage, 11... Operation lever, 12... Metering characteristic conversion section, 13... Servo valve, 14...
- Load sensor, 15... Signal control section, 17... Changeover switch. Patent Applicant Hitachi Construction Machinery Co., Ltd. Agent Patent Attorney Kazuhiko Hirose
Naoki Nakamura Figure 1 Figure 2

Claims (1)

[Claims] At least one flexible arm rotatably provided on a work machine body, a hydraulic cylinder that rotates the arm, and a control that controls the flow rate of oil supplied to the hydraulic cylinder based on a command signal. a valve, a first signal generating means for outputting a predetermined command signal to the control valve according to the amount of operation of a control lever for operating the hydraulic cylinder, and a load applied to the tip side of the arm by the work object. a second signal generating means for outputting a command signal corresponding to when the workpiece lands or cuts off the ground to the control valve based on the load signal detected by the load detecting means; and a signal switching means for selectively connecting the first and second signal generating means to the control valve.