JPS61293306A - Apparatus for controlling rising speed of working machine oftractor - 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 This invention relates to a lifting speed control device for a hydraulic lifting mechanism for lifting and lowering a work equipment connecting link mechanism provided on a tractor. The aim is to control the rising speed in order to prevent a large impact force at the beginning of the rising movement.

Conventional technology In so-called position control, in which the work equipment connected to the work equipment connection link mechanism is controlled to the vertical position specified by the operating device, due to the sudden increase in acceleration force of the work equipment at the beginning of the upward movement, , a large impact force acts on the lift arm, lift cylinder, work equipment connection link mechanism, etc. of the hydraulic lifting mechanism, and this large impact force makes it difficult to control the work equipment to a specified position. There is a problem in that wear and tear is accelerated in the hydraulic lifting mechanism, various parts of the working machine, special trap connecting bin parts, fitting parts, etc.

Problems to be Solved by the Invention The present invention aims to prevent the generation of large impact force at the beginning of the upward movement in position control, so that position control can be performed accurately, and to prevent wear and tear of related members caused by the impact force. The aim is to reduce the

Means for Solving the Problems In order to solve the problems mentioned above, the present invention has taken the following technical means.

That is, the work equipment (5) connected via the work equipment connection link mechanism (4) is raised and lowered based on the operation of the lift cylinder (8) of the hydraulic lifting mechanism r6), and the lift detector +
81 Part 11 controls the hydraulic lifting mechanism (6) so that the detected lift value of the work equipment connection link mechanism (4) coincides with the lift setting value instructed by the lift setting device (11K). A tractor having a trowel,
The control unit I is configured to gradually increase the flow rate of pressure oil to the lift cylinder (8) at the beginning of the lifting operation of the hydraulic lifting mechanism (6) by operation in the lift setting device. control of the lifting speed of tractor work equipment,
It is.

When the hydraulic lift setting device m is operated to cause the hydraulic lifting mechanism (6) to move upward, at the beginning of the upward movement, the control unit α4 slowly increases the flow rate of the pressure oil to the lift cylinder (8). The lifting speed of the hydraulic lift control mechanism (6) increases gradually rather than suddenly, allowing it to rise accurately to the position specified in the lift setting device with little error, and the impact force exerted on related parts is also prevented. This will prevent wear and tear.

Example Next, one embodiment of the present invention will be described based on the drawings.

The tractor (1) shown in Figure @3 is connected to the work equipment connecting link mechanism (4) through the left and right lower links (2) (21 and the top link (3) at the upper center). The machine (5) can be raised and lowered by a hydraulic lifting mechanism (6), and the lift arms (7) of the hydraulic lifting mechanism (6) are connected to an oil pump (9) to a lift cylinder (8). The pressure oil in the lift cylinder (8) is supplied to the lift cylinder (8), causing it to rotate upwardly.
The supply and discharge of the pressure oil to and from the lift cylinder (8) is controlled by moving the lift switch (Il+) to the ascending position (individually) or to the descending position (individually). By operating each, the 11-ft setting value specified by the lift setting device (T), which is like a volume, and the vertical position of the working Sakaki connection link mechanism (41) detected by the lift detector (SIK) are adjusted. Based on the difference between the detected value of This is done by selectively operating the solenoid valve 09 and the lowering solenoid valve (1e). Lift detector 1s composed of kimono
It is detected by K.

In order to adjust the lifting and lowering speed of the lift arm (7), the flow t (per unit time) of pressure oil to the lift cylinder (8) is adjusted. This flow rate adjustment is performed using an electromagnetic control valve ( This is done by adjusting the opening area of the oil passage in (2), and the current for opening and closing the oil passage when closing the electromagnetic control valve is performed by a pulse current as illustrated in FIG. By command, the pulse @ (T1) of the on part of the pulse current given to the electromagnetic control valve (VIK) is widened as shown in Fig. 5.

The pulse current applied to the electric Wi control valve is connected to the opening surface P! The configuration is such that when t is widened, the flow rate is increased, and when the pulse width (T'1) T7 is narrowed, the opening area is narrowed.

Flow rate of lift cylinder (8) lol! 4WJ, that is, the speed adjustment of the lift arm (7) is performed when a lift command is issued by operating the lift setting (lift setting value>lift detector)
As shown in the characteristic diagram in Figure 6, the speed is low at the beginning of the lift operation, but gradually increases as the lift arm (7) rises, reaches (Zone Z+), and then as it approaches the lift set value. On the contrary, the speed gradually decreases (zone Zl) to alleviate the large impact force at the beginning of the rise of the hydraulic lifting mechanism (6) and near the stop, and to ensure that the stop position is accurate. When a lowering command is issued by the device (lift setting value - lift detection value), the impact force at the beginning of lowering is not a problem, so the lowering is performed rapidly (zone Z4) as shown in Figure 7 to reduce the delay in operation. However, as it approaches the set value, the speed gradually decreases (Zone Zs), so that the impact force at the time of stopping is reduced. 7 The movement is performed slowly near the upper and lower limits of the toe arm (7), but a constant rapid movement is performed outside of these areas.

Then, as shown in the flowchart of Fig. 2, when a lift command is issued by the lift setting device +11 (step ■,
■), it is determined whether the lift setting return has just been operated (for example, by determining that the number of registers increases each time step ■ is passed), and if it is, the pulse of the ON part of the pulse current The initial width value is set (step ■), the pulse width correction value (field), the maximum value and the minimum value of the pulse width are both set (steps ■, ■),
A pulse current with the pulse width of the above initial value is output from the control unit (14), the lifting solenoid valve α9 is driven, the lift cylinder (8) starts operating, and the lift arm (7) starts to rise gently. Then, the pulse width correction value (d) is added to the initial value of the pulse width (step ■), and the pulse width of the pulse current after this point is determined to be output by the correction value (φ). Solenoid valve for rising 0
The flow rate will further increase, and as long as it does not reach near the lift set value and the pulse width does not exceed the large volume value, a correction value (φ) is added to the pulse width (steps ■,
(■, ■) In this way, the pulse width of the ON part of the pulse current gradually becomes wider as shown in Fig. 5, and the flow rate of the rising solenoid valve a9 increases rapidly, and the pulse width exceeds the maximum value. When the pulse width reaches this maximum value, the flow rate is limited and the lift cylinder (8) is subsequently operated at this maximum flow rate until it reaches near the lift set point.
will move upward (zone z3 in Figure 6),
When approaching the lift setting value, the pulse width will increase by the correction value + (
! Correction is performed so that it becomes narrower by l (step ■, @
), the flow rate of the rising solenoid valve 09) gradually decreases,
When the lift arm (9) reaches the lift set value, the oil passage of the lift solenoid valve α9 is closed (step ■).
The lift arm (7) will stop.

When a descending command is issued by the lift setting device (TIK), the pulse width is set to a sufficiently wide initial value for descending, and the oil passage of the descending solenoid valve qF3 is greatly opened at 1 o'clock (step [phase ], @) Also known as K, the lift arm (7) remains at a high speed until the lift set value is reached.
continues to descend (Zone Zs) and when it reaches near the lift set value, the pulse width is sequentially corrected so that it becomes narrower by the correction value (C (step [phase], ■), and the lowering solenoid valve (The flow rate of 161 gradually decreases, and when the lift set value is reached, the oil passage of descending renoid valve 4 is closed (step ①).

In addition to the illustrated example, the lift detector +81 may be one that detects, for example, the elevation angle of the lower link (2), and is not limited to the illustrated example.

Effects of the Invention The tractor work equipment climbing speed control device according to the present invention is constructed as described above, and when the hydraulic lifting mechanism (6) is operated to ascend by operating the lift setting return, the lifting speed control device according to the present invention Since the control unit I slows down the increase in the flow rate of pressure oil to the cylinder (8), the rising speed of the hydraulic lifting control mechanism (6) can be increased, and the impact force exerted on related members is also not excessive. This made it possible to prevent wear and tear.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention, in which Fig. 1 is a control block diagram, Fig. 2 is a flowchart, Fig. 3 is a side view of the tractor, Figs. 4 and 5 are characteristic diagrams showing pulse current, and Fig. Figure 6 and Figure WC7 are characteristic diagrams for speed control. Description of symbols (4)... Work equipment connection link mechanism (5)... Work equipment (6)... Hydraulic lifting mechanism (8)... Lift cylinder a4... Control section (81...
・Lift detector (T)... Lift setting device Fig. 4 Fig. 5 Fig. 6 Mu, I1 [

Claims (1)

[Claims] The work equipment connected via the work equipment connection link mechanism is raised and lowered based on the operation of the lift cylinder of the hydraulic lifting mechanism, and the lift detection value of the work equipment connection link mechanism detected by the lift detector is The tractor has a control unit that controls the hydraulic lifting mechanism to match the lift setting value instructed by the lift setting device, and at the beginning of the lifting operation of the hydraulic lifting mechanism by operating the lift setting device,
A working machine lifting speed control device for a tractor, characterized in that the control section is configured to slow the increase in the flow rate of pressure oil to the lift cylinder.