JPS5911794B2 - valve device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to valves, and more particularly to regulating pilot valves.

It is now known to use pilot valves to control and operate main control valves.

Among the advantages of control using a pilot valve are the ability to remotely locate the operator's control unit in addition to reducing the operator's effort when starting the control valve.

Since the capacity and pressure required for the pilot system are low, remote control can be carried out inexpensively and advantageously by this pilot control.

For these same reasons, the worker's effort is also significantly reduced.

Obviously, for example, fluid-operated machines requiring very large volumes and pressures must use very large control valves that require large forces to move and at the same time achieve their control action. In order to do this, you must necessarily do a lot of exercise.

For these reasons, pilot control is particularly desirable in the control system of fluid-driven machines.

This pilot control is particularly desirable in machines that require large pressures and capacities to operate the machine.

Examples of machines that require large volumes and pressures include loader-1 excavators and hydraulic cranes.

Fluid excavators especially require effective pilot control of the fluid system.

The need for pilot control is particularly great because extremely high pressures and volumes of fluid are typically used and required to operate this fluid system.

Pilot control is particularly desirable in such installations since the expense of providing control valves near the workroom and operating them through typical linkage systems is prohibitive.

Providing control valves in this manner requires very expensive conduits and fittings and requires complex arrangements of conduit systems.

Pilot operation is also desirable for such machines.

This is because the operator has to carry out a large number of repetitive control movements during the normal operation of the machine.

Piloting can significantly reduce the force that the operator must exert himself to start and control the fluid system.

This significantly reduces fatigue and allows the operator to continue operating the machine for a long period of time.

However, currently known pilot control systems have the disadvantage that they are not fully satisfactory for use in fluid drilling machines.

Currently known pilot control systems do not provide the operator with the precise sense of control needed or desired for this machine.

Due to the nature of the work expected of excavators, they must be capable of receiving a very wide range of power and moving at a wide range of speeds.

Many functions within these broad ranges must be performed under precise and accurate control of the operator in order for the machine to be used safely and efficiently.

To achieve this necessary control, pilot and control valves must be designed to provide effective and precisely controllable adjustments to their respective fluids.

A number of valve structures are known for regulating control fluid.

The prior art includes, for example, the following U.S. patents, namely U.S. Pat.
No. 971536, No. 3477225, No. 348641
No. 8 and No. 3,556,155.

These patents illustrate prior art solutions to regulatory control of either main control valves or fluid motors.

However, this problem is different in each case.

Although techniques for regulated control of fluid motors are often applied to pilot control of control valves and vice versa, pilot control regulation presents unique problems not found in motor control systems.

For example, the force required to move a motor is determined by the load placed on the motor, but the force required to move a main control valve depends on its position relative to its center. Normal.

Thus, although the pilot valve is displaced to position the control valve, the control valve has the function of obtaining a motor movement opposite to its positioning.

Another additional problem with pilot control systems is that the indirect connection between the operator-operated activation lever and the main control valve eliminates the sense of control over the equipment.

When this sense of mechanical control is lost, the machine typically rattles and moves erratically.

Therefore, machine operation is often dangerous and inefficient.

Therefore, the main object of the present invention is to provide a pilot control valve that solves the above-mentioned problems of the prior art.

Another object of the invention is to provide a pilot valve that operates to precisely control a control valve.

Yet another object of the invention is to provide a pilot valve with suitable adjustment means which serves to precisely and accurately control the main control valve.

Yet another object of the present invention is to provide a pilot valve adjustment means that operates to precisely step increase the control pressure that activates the main control valve.

According to the invention, the pilot valve that starts the main control valve is
Appropriate throttling means are provided for regulating the control fluid to precisely step increase the control pressure in order to completely precisely control the positioning of the main control valve.

The above and other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

Referring now to the drawings, and in particular to FIG. 1, there is shown a preferred embodiment of the invention as applied to a pilot valve, designated generally at 10.

The illustrated embodiment includes a pair of substantially parallel cylindrical holes 14.14.
The pair of cylindrical holes 14, 14' are provided with the same control spool 16°1.
6' is provided so as to be able to reciprocate.

Inlet passage 18 intersects both holes 14, 14' to supply pressurized fluid from pump 20 to be directed by these spools to various outlets.

A pair of return passages 22 , 24 are located on either side of the inlet passage 18 to return fluid to the sump 26 through the holes 14 , 14 ′.
It intersects with

Pilot control passages 28, 30 and 28', 30' are provided with separate holes 14 for communicating pilot control fluid to the main control valve.
, 14'.

Hereinafter, since the two spools are the same, only one spool will be described in detail, and the structure of the other spool will be designated by the same reference numeral with a dash.

Each of the spools 16 is provided with an annular groove 32 , 34 , which defines a central projecting area 36 .

Another pair of annular grooves 38.40 are formed on the outside of the previously described grooves and these grooves 3840 define a projecting area 42.4.
4 is formed.

These grooves, along with the plurality of orifices described below, operate to control fluid flow from the inlet to the pilot passage and return passage.

Regulating means in the form of a plurality of metering slots and orifices are provided for regulating the control fluid to provide single-stage or multi-stage actuation of the control valve.

The metering means includes a first fixed orifice 46 communicating between the annular groove 32 and the outer surface or outer diameter of the protruding region 36 and a first fixed orifice 46 communicating between the annular groove 34 and the outer surface or outer diameter of the protruding region 36. 2 fixed metering orifices 48.

Means in the form of transverse slots 50, 52 are provided for immediately activating the orifices 46, 48 when the spool is moved into position communicating the ends of the slots with the supply passage.

The variable orifice 54 , 56 runs parallel to the fixed orifice and has the form of a slot extending from the groove 32 , 34 to the central projecting area 36 .

The slots of the variable orifice 54.56 open the inlet 18 and the outlet 2 immediately after the fixed orifice 46.48 is fully engaged.
8.30 immediately reaches a constant minimum value, and then gradually increases from this minimum value to completely open the pilot valve.

Another pair of metering orifices or passages 58.60 are provided in series with said metering orifices, these metering orifices 58.60 are connected to the inner grooves 32, 34 and the outer grooves 38.40.
communicate with.

These passages form pilot discharge passages for the control passages 28, 30 when the valve 16 is in the neutral position, and the metering orifices communicate between the inlet 18 (!: control passages 28, 30). During at least a portion of the period, the pilot pressure to control passage 28.30 is partially reduced.

These passages 58.60 are operative when the outer grooves 38.40 communicate with the outlet passages 22.24, but become inoperable as soon as one of these grooves is blocked by moving out of the discharge passage. .

Since tight alignment of the orifice and passageway of the pilot valve spool 16 is required, suitable means are provided to prevent rotation of the pilot valve spool 16.

This means for preventing rotation of the spool consists of a flat portion 62 formed in the spool 16 into which a dowel pin 64 retained within the hole 66 engages, such as a plug or screw 68. is positioned to do so.

Suitable centering means 70 for the spool are provided, which means may take any form known in the art, but are preferably as shown.

However, this centering means must coordinate its centering action to be compatible with the other adjustment actions of the valve in order to obtain the new results sought by the present invention.

For example, in a preferred embodiment, the first spring centers the spool, so that at some point, such as just before the start of the adjustment action, the second spring centers the spool.
The spring is set to play.

The pilot valve is operatively connected to control or operate a main control valve 72 in the illustrated embodiment.

The pilot valve is connected by pilot line 74.16 to pressure chambers 78, 80 in which pressure is applied to the end of control spool 82 to move the control spool to a selected control position.

The valve 72 may be of any suitable type, such as that shown, which in the case shown has a neutral position and which, when moved to either side of this neutral position, causes the reciprocating motors to move between the two respective It has the function of supplying pressurized fluid to move in the direction.

This main control valve typically has known means for regulating the control fluid.

The valve spray also typically has a normal dead phase to properly seal the valve spool.

Dead phase is defined as movement of the valve spool that does not increase or decrease the fluid flow rate across the valve spool, and thus does not increase or decrease the speed of the machine.

The movement of main control valve spool 82 is graphically illustrated by the solid line in FIG.

The movement of the main control valve spool from point J to point J is a dead-phase movement in which fluid flow from the supply passage to the control passage is blocked by the valve spool.

This movement is about 5.6 mm (0.22 inches) of movement, which is about 33% of the total movement.

The movement of the main control valve spool from point M to point M corresponds to an adjustment range in which fluid flow from the inlet passage to the control passage is controlled by the metering orifice in the valve spool.

This movement ranges from approximately 5.6 mm (0,22 inches) to approximately 11
．． The movement is up to 9 mm (0.4 finch), which is also about 33% of the total movement.

In the movement of the main control valve spool from point M to point N, the inlet passage is fully opened to the control passage through the annular groove of the valve spool.

This movement ranges from approximately 11.9 mm (0.4 inch) to approximately 1 inch.
The movement up to 7.5 mm (0.69 inches) also accounts for about 33% of the total movement.

This final movement of the main control valve spool can also be considered a dead phase movement since it merely provides more unobstructed fluid flow without significantly increasing the speed of the controlled work equipment.

In FIG. 3, the movement of the main control valve spool 82 is shown in solid lines, while the movement of the pilot valve spool 16 is shown in dotted lines.

The corresponding manual lever movement required to move this pilot valve spool 16 is shown in dotted lines in FIG.

The solid line in FIG. 2 indicates the movement of a manual lever attached to a conventional conventional valve spool such as the main control valve spool 82 or a conventional conventional pilot valve spool having general flow characteristics similar to the control valve spool 82. There is.

A more complete understanding of the physical characteristics of pilot valve 10 is that pilot valve spool 16 has a total travel distance of approximately 7
．． The sequence of events that occurs as the main control valve spool 82 is shifted as it travels through a 92 mm (0.312 inch) full stroke will appear from the following description.

The first O of the pilot valve spool 16 ~ 0.79 mm (
0,031 inch) in any direction (for example, to the right)
The movement to is a dead phase movement, at which time fluid flow between the inlet passage 18 and the pilot control passage 28 is blocked.

When the valve spool has moved approximately 0679 mm (0,031 inch) (point F in Figure 3), the lateral slot 50 is in the inlet passage 1.
8 and fluid flow through orifice 46 begins to provide pilot pressure to conduit 74 and pressure chamber 78 .

The transverse slot 50 allows almost instantaneous operation of the fixed orifice 46 with very little movement of the valve spool.

The restriction by the second orifice 58 on the effective cross-sectional area of the first fixed orifice establishes a pilot pressure.

The pilot pressure in the pressure chamber 78 is approximately 1.47 kg/i (2
1 psi), the main control valve spool 82 moves very quickly against only the low spring rate spring from point J to point J in FIG.

At this point the main control valve spool contacts the second control spring.

Pilot valve spool 16 is 0.79 Wtm (0,
031 inch) to approximately 1.8 (0,0 inch) (
Moving from point F to point F), the transverse slot 50 opens further into the inlet passage 18 to increase the flow through the throat 46 and the pilot pressure in the pressure chamber T8 is approximately 3.5 kg/
art (50 psi).

The two orifices 46,58 arranged in series allow precise control of the pilot pressure, from the point at which the transverse slot 50 begins to open (point F) to the point at which the orifice 46 is fully opened into the inlet passageway 18 (point D). Gives a high rate of increase in pilot pressure until

The increase in pilot pressure in pressure chamber 78 begins to compress the high spring rate control spring and moves main control valve spool 82 approximately 0.22 inches (point L in FIG. 3).

This is the beginning of the adjustment range, at which point the metering slot at the left end of the main control valve spool 82 begins to open to a supply passage connected to a main source of pressurized fluid, not shown.

The movement of the main control valve spool between point J and point J is considered a dead phase movement since the flow of fluid from the supply passage is blocked by the control valve spool.

The 1.8 mm (0,0 inch) movement of the pilot valve spool until it lights up is 7,9 tttm (0,312 inches).
This corresponds to approximately 15% to 18% of the total amount of movement.

This ranges from about 15% to 18% as shown by the dotted line in Figure 2.
Corresponds to manual lever movement of %.

The pilot valve spool 16 extends from 1.8 mm (0.0 inches) to 6.4 inches (0.25 inches) (from point G to point G).
), the fluid flow through the variable orifice 54 joins the fluid flow through the orifice 46, so that the pilot pressure directed into the pressure chamber 18 increases in proportion to the movement of the pilot valve spool. Approximately 12.3 at point G
kg/crtt (175psi).

As a result, the main control valve spool is approximately 11.9 mm (0
, 469 inches), and at this time the annular groove at the left end of the main control valve spool opens to the supply passage, so that contact point M is at the end of the adjustment range.

In order to provide a small rate of advance movement of the main control valve spool in the adjustment range between the dot and point M, the pilot pressure increase rate between the dot and point G is relatively small relative to the movement of the manual lever. .

Point M corresponds to the end of the pilot valve manual lever adjustment range corresponding to point E in FIG.

The movement of the pilot valve spool 16 from point to point G is the second
This corresponds to the movement of the manual lever from dot to E in the figure, which corresponds to about 65% of the movement of the manual lever.

The movement of the pilot valve spool 16 is approximately 6.41L7IL
(0.25 inches), the second fixed orifice or passageway 58 closes, and the pilot pressure within the pressure chamber 78 increases rapidly to approximately 22.8 kg/crit (3
A maximum pressure (point H) of 25 psi) is reached.

The sudden increase in pilot pressure within the pressure chamber 18 causes the main control valve spool 82 to rise approximately 11. It is quickly moved from 1 m (0,469 inches) to the total movement distance of 17.5 mm (0,688 inches) (from point M to point N).

This large pressure increase during movement of the pilot valve spool is obtained by approximately 16% movement of the manual lever corresponding to point E to point C in FIG. Approximately 1/3 round motion is applied to the control valve spool.

The solid line in FIG. 2 shows the relationship between the movement rate of the manual lever and the speed ratio of the machine in the control means using the known valve spool having the above-described configuration, in which control over the entire speed ratio range of the machine is possible. This is done within a range of 1/3 of the manual lever movement rate.

That is, a conventional valve must travel from zero to approximately 33% of its total movement (point A) before machine movement begins.

Therefore, the adjustment range is from 33% when the machine starts moving to about 66% of the lever movement when the machine speed reaches 100% (point B
).

Valve movement from this point B to 100% (point C) covers the dead phase motion range where more unobstructed fluid flow is provided without increasing the speed of machine motion.

On the other hand, as described above, the case using the piedant control valve according to the present invention is shown by the dashed line, and as shown by the dashed line, the band movement extends to only about 15-18% (point D);
At this point, accommodation begins and extends to around 80-85% of the total movement (point E).

The use of a pilot valve according to the invention thus has the advantage of reducing the band movement of the control lever, while at the same time widening the adjustment range to around 65% of the lever movement.

Referring again to FIG. 3, the pilot spool travel compared to the control spool travel is shown.
Both are graphed against pilot pressure.

From this diagram, it is also possible to read the multiple of the amount of movement of the control spool due to the movement of the pilot spool.

Comparing these two graphs, the advantages of the pilot system according to the invention can be seen from the figures.

The relative position of the pilot valve spool and the main control valve spool and the pilot pressure that moves the main valve spool to a predetermined position can be determined by simply projecting a vertical line and a horizontal line between the curve and the coordinates of the graph in Figure 3. can be measured against.

For example, to measure the amount of movement of the main control valve spool relative to the amount of movement of the pilot valve spool of 1/10 of an inch, first 2.541! on the horizontal axis! ! 71 (0,10
Draw a vertical line upward until it intersects the dashed curve of the pilot valve spool.

Next, draw a horizontal line from this intersection to the right until it intersects the solid curve of the main valve spool.

Further, draw a vertical line downward from the intersection point until it intersects the horizontal axis of the graph, and from the intersection point on the horizontal axis, the main valve spool will move approximately 6.5 mm (0.1 inch) for the pilot valve spool's movement of 2.54 mm (0.1 inch). A movement of 6 mm (0.26 inches) is measured.

The amount of pilot pressure to move the main valve spool 6.6 mm (0,26 inches) by extending the horizontal line between these curves to the vertical axis is approximately 492.19
/ff1 (70 PSI) is required.

As can be seen from the above description, a novel pilot control valve arrangement is provided having means for providing stepwise modulated control to extend the control range of the main control valve and reduce its dead phase.

According to the invention, the pilot pressure rises rapidly and displaces the main control valve through the non-operating position, i.e. the round band position, to the point where regulation begins, and at this regulation start point the pressure increase is caused by a long movement of the pilot valve. Gradually increases over the range to give a wide range of adjustment control to the main valve spool.

Once the adjustment range is exceeded, the pilot pressure rises rapidly again, rapidly displacing the main control valve to its fully open position.

Although the invention has been described with respect to one particular embodiment, it should be understood that various changes may be made in the structure and arrangement of the parts of the invention without departing from the spirit and scope of the invention.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of a pilot control valve to which the present invention is applied, Fig. 2 is a graph of machine speed versus control movement, and Fig. 3
The figure is a graph of pilot pressure versus valve spool movement. 10... Pilot valve, 12... Housing, 13.14'... Cylindrical hole, 16.16
'... Control spool, 18... Inlet passage, 20... Pump, 22° 24...
Return passage, 28, 28', 30, 30'...Pilot control passage, 32, 34, 32', 34'
......Annular groove, 46.46'...First fixed orifice, 48.48'...Second fixed orifice, 50°52... Horizontal slot, 54
, 56...variable orifice, 72...
Main control valve, 82... Main control spool. 199-

Claims (1)

[Claims] 1 a main control valve spool for controlling fluid that operates a motor, a source of pressurized pilot control fluid, and a pilot control valve operative to direct the pilot fluid to operate the main control valve spool. , the pilot control valve has a fixed axial orifice extending from the annular groove to the projecting region, and a variable orifice extending from the annular groove to the projecting region, the fixed orifice and the variable orifice defines a regulating means operable to communicate pilot fluid from the inlet passageway to the pilot control passageway, the annular groove communicating with the pilot control passageway and the projecting area facing the inlet passageway; The pilot control valve has a first position in which the fixed orifice supplies pressurized fluid to the main control valve to accelerate movement of the main control valve spool through a dead zone range and movement of the pilot valve through a range of adjustment. A valve arrangement movable to a variable position in which said variable orifice adjustably supplies pilot fluid to a main control valve in addition to that supplied by said fixed orifice for proportional movement.