JP3124285B2 - Control valves for flow or pressure control - Google Patents

Description

The present invention relates to a control valve according to the preamble of claims 1 and 2.

[Prior art] This type of valve is used as a flow control valve in DE-C3420194 (IP-13).
It is known based on 44). In this case, in the event of a failure, the safety hole provides a sufficient supply of liquid to the outlet side, ie the control valve closes the control hole in the event of a spring failure due to breakage or loosening of the spring or when the viscosity of the liquid increases significantly.

After a predetermined pressure difference, the safety hole is fully opened, and the control valve operates outside the control range. When the pressure difference is reduced again, for example by interrupting the liquid supply or decreasing the viscosity due to heating, the control piston, formed as a ring, is returned to the control range by the force of a spring.

In this known flow control valve, the safety hole is arranged such that the flow through the measuring orifice and thus the resulting pressure difference is zero when the control opening is closed, whereby the spring always brings the control valve into the control range. . In this case, the safety hole has the function of a bypass for the flow through the measuring orifice.

Other configurations are known which basically do not allow the provision of a safety hole as a bypass. However, even in this configuration, it is preferable to provide a safety hole in a pressure control valve for controlling oil pressure in an internal combustion engine, for example.

[Problems of the Invention] An object of the present invention is to provide a safety hole in a control valve of this kind so that the control valve returns to the control range again when a pressure peak occurs after the control valve deviates from the control range. .

[Means for Solving the Problems] The gist of the present invention that has solved the above problems is described in claims 1 and 2.
It is as described in.

Advantages of the invention The advantage of the present invention is that the cross-section of the safety bore is such that the remaining spring force always returns the control piston again to its control range and keeps the lubricating oil supply connected. The only limitation is that the pressure rise at the outlet side or the flow velocity at the measuring orifice can be limited only by the dimensions. No other measures are required. In a pressure control valve, the pressure rise on the outlet side acting on the control piston in the direction of opening the safety hole is limited, and in a flow control valve, the pressure difference acting on the measurement orifice is controlled at most by the small size of the safety hole. The piston is only returned to its control range by a spring load after the occurrence of a pressure peak. For accurate sizing of the safety hole, consumption at the outlet side of the valve is also taken into account. This is because the consumption-dependent pressure rise at the outlet side of the valve or the load-dependent flow at the measurement orifice of the valve is limited by the cross section of the safety bore. For example, the control range of such a pressure control valve lies between 4 bar and 2 bar. The ring or the control piston is always returned to the control range if the cross-section of the safety hole is designed to be narrow so that the pressure rise in this case remains below 2 bar with the safety hole opening taking into account the consumption on the outlet side.

FIG. 1 shows a control valve for controlling pressure, and FIG. 2 shows a control valve for flow. The flow direction of the control valve is indicated by the reference numeral 3. An oil line 2 opens into the valve housing 1 at its pressure medium inlet, in which a control piston 9 is guided in an axially displaceable manner. On the outlet side, the valve housing 1 is provided with two connecting lines which open into the valve housing 1 by means of a control opening 8 or a safety hole 16. Depending on the axial position of the control piston, the oil line on the inlet side is connected to the oil line on the outlet side via a control opening as well as a variable open cross section of the safety bore. For this purpose, the control piston 9 is provided with two control edges 10, 17;
Cooperates with the control opening 8 and the other control edge 17 cooperates with the safety hole 16. The important point in this case is that upon movement of the piston in the direction of closing the control opening 8, the associated safety hole is opened in the opposite direction, even before the control opening is completely closed. Due to this, the distance between the control edges 10 and 17 is made slightly larger than the distance between the control opening and the safety hole. In short, an interflow occurs between the control opening and the safety hole when the valve is opened and closed. Each of the control pistons shown in FIG. 1 and FIG.
The compression spring acts to move the control piston in the control opening opening direction. As the control piston moves in the direction of opening the control opening, it simultaneously passes through the safety hole 16 in the direction of closing. Each control piston is provided with a pressure receiving surface 20 and an opposing pressure surface 21 which moves the control piston in the direction of closing the control opening 8 when a pressure is applied. In contrast, the opposing pressure surface 21 causes the control piston to move in the direction of opening the control opening by the force of the spring when a pressure is applied. In any case, a pressure difference eventually acts on the control piston, which causes the control piston to move to a predetermined axial position depending on the spring force. This pressure difference is formed by the difference between the pressure on the outlet side and the pressure of the surrounding air in the pressure control valve shown in FIG. Via the discharge valve 13 the opposing pressure surface 21 is only in contact with the pressure of the surrounding air, and on the pressure receiving surface 20 the pressure in the outlet conduit of the valve acts. As long as the pressure difference between the outlet pressure and the counter pressure is large enough to move the control piston against the spring force in the direction of closing of the control opening 8, the counter pressure surface will be replaced by any preload instead of ambient pressure. It may be loaded.

A measuring orifice is arranged in the oil conduit on the inlet side of the flow control valve, and the entire oil quantity on the inlet side must pass through this measuring orifice. Control conduits 22, 23 branch off from before and after the measurement orifice, respectively. Control conduits 22 each branching out of the measuring orifice
Is loaded by the conduit pressure before the measuring orifice, and the control conduit 23 branching off from the measuring orifice is loaded by a relatively low conduit pressure behind the measuring orifice. A relatively high pressure control conduit 22 communicates with a chamber closed by a pressure receiving surface 20, and a control conduit 23 opens into a closed spring chamber which includes an opposing pressure receiving surface 21.
Is located. Also in this case, the control piston 9 is under the influence of the compression spring in the opening direction of the control opening 8, and
It is important that a relatively high pressure before the measuring orifice loads the pressure receiving surface 20 in the direction of closing the control opening 8 against the spring force. The relatively low pressure behind the measuring orifice is guided via a second control conduit 23 into the closed spring chamber and loads the opposing pressure surface 21 in the opening direction of the control opening 8.
The pressure rise behind the measuring orifice causes the control piston 9 to move in the direction of opening the control opening 8.

3 to 6 show the built-in valve 4. FIG. 3 and 4 are pressure control valves, and the built-in valves shown in FIGS. 5 and 6 are flow control valves. Each built-in valve has a valve element 15. This valve element 15 is adapted to be inserted into the machine block by the expanded insertion part 5. The extended insertion portion 5 has the hole 2
This hole 2 forms a hydraulic conduit in the machine block. This conduit may be a lubricating conduit in a lubrication circuit of an internal combustion engine. The flow direction of the medium is arrow 3
Indicated by The shaft part 6 reduced in size compared to the insertion part 5 is located downstream in the flow direction starting from the expansion part in FIGS. 3 to 5, and is located upstream in the flow direction in FIG. Third
The valve shown in FIGS. 5 to 5 is provided with an axial hole 7 which opens in a co-current direction, which hole extends completely through the insert and down to the reduced shaft. At the shank, this hole communicates via a radial control opening 8 with the downstream portion of the oil conduit. In the case of FIG. 6, the flow flows through the control opening 8 into the axial passage 7 and flows out axially downstream of the outlet.

The shaft 6 is provided with an axially guided control piston 9 which is formed as a sliding ring. In the case of a pressure control valve (Figs. 3, 4, 4a
In the figure, the sliding ring is guided in a piston-like manner on the inner and outer peripheral surfaces thereof in a dense manner along the shaft and the bore of the oil conduit. In the case of a flow control valve, the sliding ring is provided with an annular ridge 19 on the outside, which, together with the surrounding oil conduit, forms an annular restriction gap or a measuring gap for forming a pressure difference in the medium flow. Orifice 18
Is formed. All sliding rings are provided with a reduced diameter section starting from a collar 12 (FIGS. 3, 4 and 4a) or an annular ridge 19 (FIGS. 5 and 6) located upstream. I have. An annular flow chamber for the hydraulic medium is formed on the sliding ring between the inner peripheral surface of the oil conduit and the outer peripheral surface of the reduced diameter portion. The slide ring is provided with a radial bore 10 in the axial area of the reduced diameter portion, which depends on the position of the slide ring the radial control opening 8 of the valve body and the downstream oil conduit. Are arranged to open a predetermined cross section therebetween. The radial bore 10 of the sliding ring therefore forms a control edge for controlling the cross section of the control opening 8 of the shaft 6. The sliding ring is supported via a compression spring 11 on the expanded insert 5 (FIGS. 3, 4a, 6) or on a snap ring 14 (FIG. 5), The spring opposes the pressure on the outlet side (FIGS. 3, 4, and 4a),
Alternatively, it is supported so as to act in the direction of full opening of the radial control opening 8 against the flow direction (FIGS. 5 and 6).

In the pressure control valve (FIGS. 3, 4 and 4a), a closed annular chamber is formed on all sides between the expanded insert 5 and the spring-side end face of the collar 12 of the sliding ring. The annular chamber is sealed to the outlet side of the oil passage by a flange 12 of the piston. This annular chamber is connected to the return line (not shown) only via the load-reducing passage 13, so that it is protected from the effect of pressure on the outlet side. The sliding ring is thereby loaded by the pressure difference between the outlet side of the valve and the return conduit, and is thereby moved to a predetermined axial position depending on the spring force. To this end, the slide ring has a pressure-receiving surface 20 for outlet pressure and an opposing pressure surface for relatively low return conduit pressure. In the flow control valve,
As the pressure oil rubs the throttle orifice, a differential pressure is created which moves the sliding ring to a predetermined axial position depending on the spring force. The pressure-receiving or counter-pressure surface is the annular surface of the annular ridge before and after the measurement orifice. The displacement of the sliding ring is downstream in the pressure control valve (Fig.
(Fig. 4a), upstream of the flow control valve (Figs.
(Figure) Limited. In this position, the radial outlet passage formed by the control opening 8 and the radial hole 10 is fully open. In this fully open position, the radial bore 10 of the sliding ring coincides with the control opening 8 of the valve body. In FIG. 3, on the downstream side, behind the radial control opening 8 of the valve body, a radial hole 16 is provided, which serves the function of a safety hole. For this purpose, the slide ring is provided with a further control edge 17, which is in this case formed by the downstream end of the slide ring. In FIG. 4, the safety hole 16 is located upstream of the radial control opening and the associated control edge 17 is formed by the radial hole 10.

In FIG. 4a, a safety hole 16 is located upstream and in front of the radial control opening, and the associated control edge is the piston collar 12
Is formed by the end face facing the valve outlet side. In the flow control valves (FIGS. 5 and 6), the radial safety holes are each located before the radial control opening 8 as viewed in the flow direction indicated by the arrow 3, so that the flow through the measuring orifice is achieved. Also forms a flow through the safety hole when the control opening is closed.

Function: As the pressure on the outlet side or the flow velocity through the measuring orifice decreases, the spring 11 moves the control piston and increases the control opening 8. This replenishes the pressure oil and increases the pressure at the outlet or the flow velocity at the measuring orifice again, whereby the control piston is pushed back against the force of the spring, which results in a force at the control piston. Balance occurs. The balance of this force depends on the preload of the spring 11, so that the pressure rise or the flow velocity on the outlet side likewise depends on the preload of the spring. For example, in order to secure a pressure rise or a flow velocity when the spring is broken, the valve inlet and the valve outlet are connected by a safety hole 16 provided within the range of the movement of the control piston 9. This safety hole is located on the control edge 17 of the control piston.
And the control piston opens just before closing the radial control opening 8 in the region of its closed position. In the event of an increase in the conduit pressure at the outlet side of the oil conduit 2 or an increase in the flow velocity at the measuring orifice 18, for example due to the occurrence of a pressure peak, the control piston moves against the spring force and completely closes the radial control opening 8. To close. At the same time, the safety hole 16 is fully opened, which ensures communication between the inlet and outlet sides of the valve, but a correspondingly large amount of pressure oil is replenished, which increases the pressure on the outlet side or the measuring orifice. It must be taken into account that a speed increase occurs. This increase in pressure or speed causes a pressure difference at the collar 12 or the annular ridge 19 of the ring or at the control surfaces 20, 21 of the control piston, which forces the ring or control piston to the spring force still present. Contrary to keep the maximum opening. The pressure or flow velocity on the outlet side increases in view of the consumption on the outlet side, so that the control piston is in the control range, ie, for example, in the sliding ring, where the radial bore 10 communicates with the radial control opening 8. The cross section of the safety hole must be sized such that the pressure differential acting on the control piston is always smaller than the dependent spring return force in order to avoid inability to return to is there. A sufficiently small cross-section limits the pressure rise at the outlet or the flow velocity at the throttle gap, resulting in a sliding ring or The control piston is again brought back into the control range by the spring force still present.

The size of the cross section of the safety hole is determined in consideration of the pressure oil consumption on the outlet side in the pressure control valve, while the flow control valve is determined in consideration of the flow of the pressure oil depending on the load. In the pressure control valve, when the consumption on the outlet side reaches the maximum value, the pressure on the outlet side becomes minimum. If, for example, a minimum consumption on the outlet side within the control range of the control piston results in an outlet pressure of 2 bar, the pressure rise to allow the safety hole to be fully open must be less than 2 bar. Only a small amount of lubricating oil needs to be replenished through the safety hole because the lubricating oil is consumed at the valve outlet side, so that the pressure at the outlet side has a lower working pressure difference than the force of the return spring. Lower until it becomes. Thus, the control piston is pushed back into its control range by the tensioned spring.

What has been said above also applies to the flow control valve.
However, in this case, the pressure oil flow flowing through the safety hole also passes through the measuring orifice. When the safety hole is fully opened, the control piston 9 is completely out of its control range. If the maximum flow through the measuring orifice is significantly increased, this keeps the control piston in the fully open position. This maximum flow rate also depends on the predetermined inlet pressure, which again depends on the load before the measuring orifice, and on the maximum available outlet pressure of the flow control valve. In addition, it goes without saying that the pressure on the outlet side of the flow control valve also depends on the flow resistance of the pipe system on the outlet side. Due to the small cross-sectional dimension of the safety bore 16, the pressure oil flow at the measurement orifice is kept large enough to limit the pressure drop at the measurement orifice. As a result, the pressure difference acting on the control piston in the closing direction of the control opening 8 is always smaller than the force of the spring 11 acting in the opening direction of the control opening 8, so that the control piston is again returned to its control range. It is.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a first embodiment of the present invention, FIG. 2 is a schematic diagram of a second embodiment of the present invention, FIG. 3 is a schematic diagram of a third embodiment of the present invention, FIG. Is a schematic view of a fourth embodiment of the present invention, FIG. 4a is a schematic view of a fifth embodiment of the present invention, FIG. 5 is a schematic view of a sixth embodiment of the present invention, and FIG. FIG. 14 is a schematic view of a seventh embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Valve casing, 2 ... Oil conduit, 4 ... Built-in valve, 5 ... Insertion part, 6 ... Shaft part, 7 ... Axial hole, 8 ...
... control opening, 9 ... control piston, 10 ... radial hole (control edge), 11 ... compression spring, 12 ... collar, 13 ... load reduction passage, 14 ... snap ring, 15 ... valve body , 16 ……
Safety hole, 17 ... Control edge, 18 ... Measurement orifice, 19 ...
Annular ridge, 20 …… Pressure receiving surface, 21 …… Counter pressure surface, 22,23
…… Control conduit

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Helmut Rommerzheim, Hützkeswagen Weilhelm-Bussieu-Week 18 Federal Republic of Germany 18 (72) Inventor Hans-Reiner Schulz Remscheid 11, Germany SHUTATUT VALT 41 (56) References JP-A-55-19816 (JP, A) JP-A-57-14912 (JP, A) JP-A-48-1000073 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G05D 7/01

Claims (2)

(57) [Claims] A control valve for controlling a flow, wherein a slidable control piston has a control opening such that the control opening is closed by movement of the control piston and a safety hole is then opened. The pressure medium inlet and the pressure medium outlet are connected to each other so as to control the cross section of the safety hole and the cross section of the safety hole which is opened and closed in a manner opposite to the opening and closing of the control opening. A pressure orifice which has two opposing control surfaces which are spring-loaded in the direction of opening of the control opening and in which the measuring orifice is arranged in the pressure medium inlet or in the pressure medium outlet; The higher pressure is withdrawn in front of the measuring orifice in direction and directed to a control surface acting against the spring force, and the lower pressure is withdrawn behind the measuring orifice and works with the spring force. Safety holes are arranged so that the flow through the safety hole always passes through the measuring orifice, and the safety hole has a maximum cross section of at least the safety hole. When the pressure medium flow on the outlet side is taken into account when the valve is fully opened, the acting pressure difference between the control surface loaded with the lower pressure and the control surface loaded with the higher pressure is smaller than the return force of the spring. A control valve for controlling a flow, characterized in that it is sized to always be small. 2. A control valve for controlling pressure, said slidable control piston having a control opening such that a control opening is closed by movement of the control piston and a safety hole is then opened. The pressure medium inlet and the pressure medium outlet are connected to each other so as to control the cross section of the safety hole and the cross section of the safety hole which is opened and closed in the opposite manner to the opening and closing of the control opening. A control surface that is spring-loaded in two directions and acts in two opposite directions,
Both control surfaces are loaded by the higher pressure and the lower pressure, where the higher pressure acts against the spring force, the higher pressure being the outlet pressure of the control valve and the lower pressure being the lower pressure. Where the pressure is of the type of ambient air or of a suitable preload, the safety holes are arranged so that they open into the room connected to the control surface which is loaded by the higher pressure. At the maximum, the control surface loaded at the lower pressure and the control surface loaded at the higher pressure, considering the pressure medium flow at the outlet side when the safety hole is fully open, A control pressure for flow control, characterized in that the pressure difference acting on the control valve is set so as to always be smaller than the return force of the spring.