JPS60173228A - Operation mechanism for working machine - Google Patents

Abstract

PURPOSE:To save energy to be required for an operation mechanism by connecting the pressure oil of the third oil-pressure pump of the first - third oil-pressure pumps to be driven by one engine to the first and second oil-pressure circuits through a switch valve to be switched and operated by a pilot pressure. CONSTITUTION:The pressure oil of the first oil-pressure pump P1 is connected to a multiple control valve C/V through the main circuit 1 and a pressure control valve 2. On the other hand, the pressure oil of the second oil-pressure pump P2 is connected to another multiple control valve C/V through the main circuit 1 and the control valve 2. The pressure oil of the third oil-pressure pump P3 is led to the main circuit of the first and second oil-pressure pumps through a pilot direction switch valve 3 and a flow-dividing valve 7. The switch valve 3 is operated by the pilot pressure of each main circuit, and the pressure oil of the pump P3 is discharged to the tank T through the flow path 6 and also the first, second, and third pumps are connected to the same engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the operating mechanism of a type of work machine used in civil engineering construction work, agricultural work, etc. in which the engine rotational speed cannot be adjusted and operated according to the work situation.

As shown in FIG. 1, the conventional operating mechanism of this type of work machine is a fixed capacity system in which the relationship between pressure and flow rate and engine horsepower is determined. In other words, the pressure and flow rate are constant. This will be expressed as a coordinate point (P, Q) with pressure on the vertical axis and flow rate on the horizontal axis. So, in this fixed capacity system, for example, for light work such as moving quickly on level ground, a high flow rate is required to achieve speed, while a low pressure may be required. If the coordinate point for this light work is < P, , Q ), the horsepower required for it is equivalent to the low horse that passes through that point (P, , Q ), but it still has the maximum horsepower. horsepower (
pass through the point (P, Q)), and p - p
The equivalent of , is surplus (wasted) horsepower.

In addition, in such fixed capacity systems, for example,
When the pressure is high to produce force, such as when drilling hard parts, and therefore during heavy work, the flow rate is low.

If the coordinates for this heavy work are (P, Q,), the horsepower required for this is equivalent to the low horsepower that passes through the coordinates (P, Q+), but it still remains at the coordinates CP.
, Q), and Q −
Anything equivalent to Q or K results in surplus (wasted) horsepower.

In order to solve this problem, it is possible to adopt a constant horsepower control method in a variable capacity system as shown in Figure 2, but it is possible to
The cost is about twice as high and it lacks practicality.

In view of these problems, the present invention has been developed through intensive research.As shown in Fig. 3, if a dual-pressure control method is adopted in a variable capacity system, it will be possible to perform high-pressure work (heavy work) that requires exerting force. ), and also for low-pressure work (light work) that requires rapid performance, it was discovered that an engine with a low horsepower output could be used, and it was completed based on this new knowledge.

That is, the present invention provides a new operating mechanism for a work machine that is low-cost and efficient, in which a low-horsepower engine is automatically switched to an appropriate capacity depending on the type of work to perform work in an energy-saving manner. The purpose is to

For this purpose, the operating mechanism of the working machine of the present invention is provided with a main circuit that communicates between the tank and the operating cylinder of the working section, and a pilot flow path that operates the pilot directional control valve is connected to the main circuit. In this case, the pilot directional control valve is capable of switching between return times NK and NK to directly return the oil in the subcircuit connecting the tank and the main circuit to the tank by pressure fluctuations in the pilot flow path that is tilted therein, and The pump provided in the subcircuit and the pump provided in the subcircuit are connected to the output shaft of the same engine.

Hereinafter, the present invention will be described in detail with reference to illustrative embodiments.

In Fig. 4, (1) is a pair of main circuits, which connect a tank T and a cylinder of a working part (not shown) to a control valve C.
/V and a pressure control valve (2). The main circuit +11, in which the control valves C/V are arranged in multiple series and can communicate with various working parts, includes:
Connect a pilot flow path (4) that operates a pilot directional control valve (3). And the pilot directional control valve (
3) is the pressure fluctuation in the pilot flow path (4) flowing there, which causes the sub-circuit (5) connecting the tank T and the main circuit (1) to
) return circuit (6) that returns the oil directly to the tank T.
It is possible to exchange it for 1 time.

(7) is a division valve installed in the subcircuit (5), (8) is a reverse rI- valve installed between the division valve (7) and the main circuit (11), and (9) is a The throttle valve 00) interposed between the pilot flow path (4) and the return circuit (6) is a check valve interposed in the pilot flow path (4).

Each of the main circuit fi+ (1) and the sub circuit (5) is provided with pumps P, P2, 1, respectively, and each pump P, -P,
- P3 operates in conjunction with the output shaft 01)K of the same engine E. (121 is a strainer. Pump P.

Pump P2 has the same capacity as pump P2, and pump P3 often has a different capacity from them.

Now, if we use pumps P1 and P2 with a capacity per revolution of 25cc and pump P3 with a capacity of 30cc, and select an engine output shaft with a revolutions per minute of 20ORPM, the capacity per minute of each pump will be For pump P1, 25 x 2000-501/mi
.

For pump P2, 25 x 2000 = 50
For pump P3, add 210'/,! Assuming that a pressure of
(5 (1 + 50) x 210 x 1.1 = 50.7
ps56 On the other hand, during light work, set the pilot flow path (・1) to 130~
Assuming that a pressure of Horsepower is similarly calculated as (nu) + 50 with a margin of 11.
+60) X 130-4.6×1゜I=50.2P
Therefore, in both high-pressure work and low-pressure work, the horsepower is approximately equal to 2, and the engine E with the same horsepower can be set.

This will be explained in comparison with that of a conventional fixed capacity system. In Figure 3, C is a straight line of engine horsepower based on the relationship between pressure and flow rate in a conventional fixed displacement system, and point C
P, Q), the engine horsepower capable of low-pressure work that increases the flow rate and increases speed for flat driving etc. is represented by a separate straight line A, and the point (210-160
), so in this system, if the direct MC represents the maximum engine horsepower, it would have to be replaced with an engine of a different capacity represented by straight line A. However, the two-pressure control method using the variable capacity system of the present invention is as shown by the straight line BK in Figure 3, and by making the product of pressure and flow rate the same, one side of the current or pressure is increased, For example, point (210・100)
Or, it can be a point (130/160), and the line C is 1. The capacity can be increased by that much, resulting in the ability of the straight line A.

As described above, the operating mechanism of the working machine of the present invention is provided with a main circuit that communicates between the tank and the operating cylinder of the working part, and the main circuit includes a pilot flow path that operates the pilot directional control valve. connected, the pilot directional valve is
Due to pressure fluctuations in the pilot flow path flowing therein, the oil in the sub-circuit connecting the tank and the main circuit can be switched to a return circuit where the oil is returned to the tank, and a pump provided in the main circuit and a pump provided in the sub-circuit are provided. Since the two are connected to the output shaft of the same engine, the engine horsepower is lower than that of conventional fixed capacity systems.
It is efficient and meets the goal of energy conservation because it can accomplish tasks of the same capacity, and it has the advantage of being highly mobile because it can automatically respond to various tasks.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between pressure, flow rate, and engine horsepower in a conventional work equipment operating mechanism that uses a fixed capacity system, and Figure 2 is a chart that shows the constant horsepower in a conventional work equipment operating mechanism that uses a variable capacity system. Chart showing the relationship between pressure, flow rate, and engine horsepower using the control method, Part 3
The figure is a chart showing the relationship between pressure, flow rate, and engine horsepower in a working machine operating mechanism of the present invention that employs a two-pressure control method of a variable displacement system. Figure 4 shows the operating mechanism of a working machine of the present invention. It is a circuit diagram. Explanation of drawing symbols T...Tank E...Engine C/V...Control valve PIIIP2φP3
...Bonbuto...Main circuit 2...Pressure control valve 3...Pilot directional control valve 4...Pilot flow path 5-way subcircuit 6...Return circuit 7...Diversion valve 3...Reverse Stop valve 9... Throttle valve ]0... Check valve 1
1... Output shaft 12... Strainer - Patent applicant Handozer Kogyo Co., Ltd. Figure 1 Figure 3 Figure 3 Δ Weight

Claims (1)

[Claims] A main circuit is provided that communicates between the tank and the operation cylinder of the working part, and a pilot flow path that operates a pilot direction operation valve is connected to the main circuit, and the pilot direction operation valve is configured to control the pressure of the pilot flow path flowing therethrough. The oil in the subcircuit that connects the tank and the main circuit can be switched to a return circuit that returns directly to the tank by fluctuation, and the pump provided in the main circuit and the pump provided in the subcircuit are linked to the output shaft of the same engine. An operating mechanism for a working machine, characterized in that the operating mechanism is configured as follows.