DE102007018491A1 - Pressure control valve for e.g. continuously variable transmission, has rear guiding, inlet and outlet lamellas joined with pressure level, so that pressure difference between guiding lamella and adjacent lamellas is provided - Google Patents

Abstract

The valve (1) has a valve piston (4) controlling an inlet lamella (6) and an outlet lamella (8), and a screen (12) for vibration absorption attached on a rear guiding lamella (10). The rear guiding lamella and the inlet and outlet lamellas are joined with a pressure level, so that a pressure difference between the rear guiding lamella and the adjacent lamellas is provided. A predetermined leakage flow is produced by the difference through a leakage space between the joined lamellas, and realizes a static volume flow through the screen in a screen control (11).

Description

The The present invention relates to a pressure regulating valve with at least one an inlet slat and at least one drain slat controlling the valve piston and with a return lamella, to which an aperture for shrinkage damping is connected.

such Pressure control valves are well known from the prior art. Furthermore, it is known that occur in such pressure control valves that can cause undesirable vibrations under certain operating conditions occur. A usual Possibility, To reduce these occurring vibrations, is that for Example damping panels be connected to the pressure control valves. This will cause the valve piston the pressure control valve forces fluid, such as oil or the like, to displace, if he is doing a movement should. In this way occurring vibrations are reduced. by virtue of of the quadratic relationship between the displaced volumetric flow and the pressure drop across the orifice, that of the valve piston movement counteracts, eventually the damping can be realized.

at this type of vibration damping However, there is a disadvantage. For very small movement amplitudes the valve piston occurs virtually no damping effect, since the pressure change at low flow is near zero. Consequently, in particular at small movement amplitudes of the valve piston is not sufficient damping effect be made possible in the known pressure control valves.

As a result, The present invention is based on the object, a pressure control valve to propose the type mentioned, in which the damping effect is improved so that in each operating condition sufficient damping to avoid vibrations is realized.

Therefore a pressure control valve is proposed, which at least one Valve piston having at least one inlet blade and at least activates a drain slat, and which a return slat comprises, to which a shutter is connected for shrinkage damping. According to the invention Return lamella and at least one fin with a different pressure level than the one Return lamella adjacent, so that a Druckdiffe difference between the return slat and the adjacent blade is provided. This way you can the damping effect the aperture used are changed so that their operating point is moved into an area in which even at low movement amplitudes the valve piston a sufficient pressure difference at the diaphragm is generated to the caused by the vibrations valve piston movement counteract. In this way, in the pressure control valve according to the invention in all Operating states, then even with low movement amplitudes, a sufficient damping effect realized.

If the pressure control valve according to the invention z. B. is designed as a pressure reducing valve, according to a development of the invention the return lamella and the inlet slat be adjacent to each other, so that the pressure difference built up between these two fins and a leakage current is enabled. But it is also conceivable that the proposed pressure control valve is designed as a pressure relief valve. In this embodiment are the return lamella and the drain slat arranged adjacent so that the pressure difference given to the outlet lamella

By the special arrangement of the slats or the connections at the pressure control valve according to the invention is due to the existing pressure difference a predetermined leakage current generated between the adjacent fins, which is a static Flow through the aperture allows. By this static volume flow of the above-described Operating point of the diaphragm moved in the direction of higher volume flows, so that at the same deflection of the valve piston a much larger counteracting Pressure difference is caused. As a result, with only one single aperture a much larger valve damping also be realized at low movement amplitudes of the valve piston.

at This arrangement also gives a further advantage. Because at rising temperature continues to increase this damping effect, since the leakage flow of the pressure regulating valve increases with decreasing fluid viscosity and the operating point of the pressure regulating valve on in the direction of higher flow rates shifts. This effect is quite desirable because at higher temperatures others Damping effects, how about the splitting friction can decrease and thus a corresponding Compensation requirement could exist.

In the context of an advantageous embodiment of the present invention can be provided that z. B. at a pressure reducing valve be with a predetermined system pressure aufschlagte inlet slat between the drain slat and the return slat is arranged. Thus, the applied with a system pressure inlet slat depending on the position of the valve piston to the corresponding pressure control or pressure control cause a reduced discharge pressure at the drain slat. There the return slat is arranged on the side facing away from the drain slat of the inlet slat, there may be a predetermined pressure difference between the system pressure at the inlet slat and the discharge pressure at the return slat. There are also other arrangement options conceivable.

Of the Leakage gap in the pressure control valve is radially between the inner wall of the housing of the Pressure control valve and the outer circumference formed of the valve piston and allows a predetermined Leakage current between the adjacent lamellae with different Pressure level. According to one Development of the invention can the dimensions of the leakage gap are changed to the leakage current temperature and pressure dependent to influence. Thus, a desired vibration damping at the pressure control valve can be realized.

Around the pressure difference between the inlet fin and the return fin to provide, may preferably in the pressure regulating valve designed as a pressure control valve those with the return lamella connected diaphragm line to the connected to the drain slat Drain line to be connected. However, there are also other connection options conceivable.

The Pressure control valve according to the invention can for different Fields of application can be used. For example, the pressure control valve for translation control, especially in a CVT transmission, but also for clutch control or also be used for flow control.

following The invention will be explained in more detail with reference to the drawings. Show it:

1 a schematic view of a possible embodiment of a pressure control valve according to the invention 1 ; and

2 a diagram showing the pressure loss at the aperture over the flow through the aperture.

In 1 is a possible embodiment as a pressure reducing valve of a pressure regulating valve proposed according to the invention 1 exemplified. The pressure control valve 1 includes a housing 2 with a hole 3 in which the valve piston 4 slidably arranged. The valve piston 4 is via a spring element 5 biased.

The housing 2 of the pressure control valve 1 has several control fins, with a middle control blade as inlet slat or inlet connection 6 is trained. To the inlet lamella 6 is a supply line 7 connected, which is subjected to a system pressure. An outer control lamella is as a drain slat or drain connection 8th educated. The drain slat 8th is with a drain line 9 connected, which is acted upon by a reduced system pressure to the system pressure. At the end of the lamella 8th opposite side of the inlet lamella 6 Another outer slat is provided as a return slat 10 is trained. To the return slat or to the return connection 10 is a diaphragm cable 11 with a panel 12 finally connected to the drain line 9 empties.

In this embodiment shown by way of example, the inlet lamella 6 and the return slat 10 arranged adjacent, so that due to the pressure difference, a leakage flow from the inlet fin 6 over the return slat through the aperture 12 results.

The valve piston 4 points to between the inlet lamella 6 and the return blade 10 a leakage gap between the inner wall of the bore 3 in the case 2 and the outer circumference of the valve piston 4 is provided. Due to the leakage gap and due to the applied pressure difference of the predetermined leakage current between the inlet lamella 6 and the aperture 12 allows, as in 1 indicated by arrows.

The predetermined leakage current causes a static volume flow through the diaphragm 12 in the aperture line 11 , This is also in 1 indicated by an arrow. In this way, the supply line 7 through the leakage gap a leakage flow into the drain line 9 through the aperture 12 allows. This static flow through the aperture 12 shifts the operating point or operating point of the diaphragm 12 by the amount of the static volume flow in the direction of a higher volume flow.

This is in particular from the in 2 shown diagram. Because in the diagram according to the diaphragm equation, the relationship between the pressure drop P at the diaphragm 12 and the volume flow Q through the aperture 11 shown. It becomes clear that the pressure drop P at the diaphragm 12 proportional to the square of the volume flow Q is. The pressure drop P at the aperture 12 causes, as described above, a corresponding vibration damping, since the pressure drop allows against the valve piston movement directed damping movement to the occurrence of vibrations at the pressure control valve 1 to avoid.

In the pressure control valve according to the invention 1 is shifted by the static volume flow as a result of the leakage current of the operating point by the amount of the static volume flow in the direction of larger volume flows, so that as in 2 indicated the operating point from A) to B) shifts. This shift of the operating point has the consequence that a displacement of a certain volume flow Q generated by the valve piston movement causes a much greater counteracting pressure difference P than when this deflection of the valve piston 4 takes place at the operating point A). Accordingly, the present invention proposed pressure control valve 1 even at low vibration amplitudes of the valve piston 4 realize a sufficient vibration damping.

1

Pressure control valve

2

casing

3

drilling

4

plunger

5

spring element

6

Inlet lamella

7

supply line

8th

Flow lamella

9

drain line

10

Return lamella

11

dazzle line

12

cover

Claims (7)

Pressure control valve with at least one inlet flap and at least one drain slat controlling valve piston and at least one return slat, to which a shutter is connected to the shrinkage damping, characterized in that the return slat ( 10 ) and at least one lamella ( 6 . 8th ) are adjacent to a different pressure level, so that a pressure difference between the return slat ( 10 ) and the adjacent blade is provided. Pressure control valve according to claim 1, characterized in that the return slat ( 10 ) and the inlet lamella ( 6 ) are adjacent. Pressure control valve according to claim 1, characterized in that the return slat ( 10 ) and the drain slat ( 8th ) are adjacent. Pressure control valve according to one of the preceding claims, characterized in that a predetermined leakage flow through the leakage gap between the adjacent fins ( 6 . 8th ; 10 ), which generates a static volume flow through the diaphragm ( 12 ) in the aperture line ( 11 ) realized. Pressure control valve according to claim 4, characterized that the dimensions of the leakage gap can be changed in order to reduce the leakage current and pressure dependent to influence. Pressure control valve according to one of the preceding claims, characterized in that, in the case of a pressure-reducing valve, the inlet lamella ( 6 ) can be acted upon by a predetermined system pressure, and that the inlet slat ( 6 ) between the drain slat ( 8th ) and the return slat ( 10 ) is arranged. Pressure control valve according to claim 6, characterized in that the valve piston ( 4 ) a leakage gap between the inlet slat ( 6 ) and the return slat ( 10 ) having.